AT-Cut Single Crystal Quartz Wafers

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What is the Most Common Quartz Cut?

AT-Cut Quartz is the most common cut, particularly used for electronic instrument that require frequency range of 0.5 - 300MHz.

In the early 1990s, AT-cut or At-Cutter quartz crystal microprocessor was introduced as an improved alternative to standard mechanical microprocessors. The AT-cut crystal made use of a unique microdomain which has only two working directions. This small feature gave the AT-cut the ability to scale up its processing capability, and its ease of fabrication influenced the introduction of many different applications for AT-cut crystal logic elements. With the success of this device comes myriad of other related products such as logic level shift (LSS), avalanche detection, and avalanche response. Here is a short list of applications for AT-cut logic elements.

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AT-Cut Quartz Applications

Microphone - The use of at-cut quartz crystals for microphones has become a popular choice due to their excellent ability to operate at high frequencies. Using ultrasonic waves as carriers, these devices are able to achieve extremely high bandwidth and sensitivity. With the addition of a directional coupler, they can be tuned to the desired frequency. The addition of a second carrier can increase the bandwidth by a factor of three, and consequently increase the signal-to-noise ratio (SN/PI) of the microphone.

Vibration Analysis - One can simulate a large number of vibration states using a single crystal and a random background. One of the advantages of using AT-cut crystal blank is that it is inherently multi-frequency sensitive. For example, if one puts a voltmeter on a piece of graph paper and places a series of capacitors on it, one can generate a number of sinusoscaled voltage fields with varying waveform and amplitude. The resulting signals are then shown on a plot (a displacement map) by the method described above. This method can also be used to simulate an electric field that is parallel to the crystal lattice.

Densitometry - This technique uses a series of at-cut quartz crystals to obtain densitometry information on the electrical properties of a piece of material. The product characteristics can be found on the basis of the dimensions of the various interfaces. Various modeling techniques and analytical software are used to derive the electrical resistivity, density, porosity, sheath thickness, dielectric strength and hardness of the material. This method is ideal for analyzing non-porous materials like ceramics and stainless steel.

Structural Analysis - The measurement of structures is an important part of Material Science research. It is useful in the areas of bending, compressive stresses, tensile strength and strain relief, etc. In many cases, stiffness is not directly proportional to bulk thickness; however, the principle of governing tensile strengths by using at-cut quartz crystals is also applicable to thin films and thin layers. Various parameters can be measured to evaluate structural thickness including porosity, density, hardness, slip resistance, grain boundary, grain size and hardness. Some other important parameters that can be determined with the help of at-cut quartz crystals include the tensile strength, moments of instability, critical points, moments of compressive stress and compressive bending loads.

Circuit Testing - During testing, it is necessary to control the operating potentials of the device under test. For this purpose, a number of different parameters can be used like current-voltage (Ivy) and time-averaged changes in voltage across terminals. The frequency of operation of terminals can also be evaluated in relation to the quartz crystal characteristics of interest. Generally, terminals are tested at the lowest possible current setting while maximum voltage is maintained across the terminals.

Product Analysis - This technique evaluates the mechanical properties of a device. The evaluation is done through the use of tensile testing or mechanical tensile testing. The process of product analysis begins with the identification of the crystalline structure of the product being tested. Different aspects such as impurity formation, crystal lattice, structure distortion and additive manufacturing can be studied to find out about product characteristics. Then all these aspects can be compared with the expected behavior of the crystal structure during the experimental procedure to find out the deviation from the anticipated behavior.

Crystal Blanking - It is another popular technique of quality testing using at-cut quartz crystals. For this, a very small amount of the crystal blank is passed through the quartz crystal wires to make the crystal blanks. Then electric potentials are observed between the areas where the wire is passed through. If there are discontinuous changes in the electric potential at these points, then the crystal blanks have been successfully bypassed. In addition to these common methods of bypassing, some other unique characteristics of at-cut products can also be found which can only be found with the actual sample characteristics.

 


 

 

What Applications Use AT-Cut Quartz?

Quartz crystals have established themselves as precise frequency generators, but how does a thin quartz disk determine the heartbeat of an application? Quartz crystals work by determining the angle between the quartz crystals, which determine their exact frequencies as generators.

It sounds simple, but it is very complex because not all quartz blanks are the same and every quartz blank is different. The ambient temperature changes slightly, so does the frequency of the desired frequency. This affects the stability of the frequencies produced by the quartz and can cause the temperature to change more, which in turn can lead to more change.

Quartz crystals also differ in their oscillations, but not as much as other types of quartz blanks, such as quartz crystals from other parts of the world.

They act like bow tendons, alternately tensed and relieved, and the longitudinal oscillator stretches its longitudinal axis as if stretched by a rubber band. Quartz crystals made of flexible U-tube quartz vibrate mainly in the middle of the blank.

The most common type of oscillation, however, is the thick shear oscillator, and at the same time the quartz disk changes its thickness. The figure shows the vibrations of a thick - scissor oscillator and a thin - hearing oscillator.

AT-Cut Vibration Type and Temperature Coefficient Defined

Cutting quartz crystals based on mathematical calculations and removing the quartz disk from the crystal is crucial. These changes can have a serious impact on the quality of the part and can be influenced during the production process.

One of the most common angle cuts is the at-cut, which is used in the production of Jauch crystals, which is cut at an angle of 90 degrees from the centre of a crystal.

Quartz blanks produced in this way have a good temperature coefficient, and the at-cut is one of the most frequently selected angle cuts for the production of Jauch crystals. This cut can be performed at temperatures of up to 1,000 degrees Celsius and is the second most popular and popular cut in the world in the field of angle cutting.

How to Make Quartz Vibrate

To make quartz vibrate, fine electrodes must be attached to the quartz, but quartz crystals are passive components and completely useless without external voltage. The big advantage of the further processing is that the quartz crystal produced during AT grinding is twice as thick as a sheroscillator.

However, the application of electrodes is a big challenge depending on the type of vibration and the thickness of the shear oscillator makes it much easier than with the above mentioned bending and longitudinal oscillators. Nevertheless, a further processing step in quartz is also necessary: electrodes should be attached to the quartz in such a way that they only deform minimally, even when voltage is applied.

The thin metal electrodes evaporate, attach the quartz holder to the tapered end and sand the blank before removing it.

Firstly, it ensures the shape of the blank and the thickness of its scissors and oscillator, and secondly, it determines the width and length of the AT and AT section. The AT cut thus fulfils the dual function of quartz production: Firstly, it ensures the smoothness and uniformity of all the scissors in the quartz and the stability and stability of each individual scissors.

Quartz Temperature Vs. Frequency

The FV performance is measured in parts per billion (ppb), and the SC cut will provide improved oscillator performance. Frequency and temperature stability is a specification that describes how the frequency output of an oscillator changes at each temperature.

Normally the incline of the SC section is bent, and the main reason for this is the steep curve (crystal bending point).

Compared to 27C. AT, SC will achieve greater stability in this range, and this improvement could be up to 5x over the extended temperature range. SCs can be cut at a bending temperature of 30 - 40C, which is much higher than for downhole applications. This is a great opportunity to improve the performance of the FAT, but not as much as the bending temperatures.

Quartz Crystal Aging

The ageing of a crystal is described in the specification described in the first part of this article "Aging of a crystal: a chemical analysis of crystal ageing."

Crystal aging is caused by impurities in the oscillator and is also measured with ppb. SC grinding is measured in ppB for the aging effect of the casting molding and the aging effect of the crystals when casting.

What is G-Sensitivity?

G - Sensitivity describes the sensitivity of the human body to changes in temperature, pressure, humidity and other environmental factors.

Quartz crystal is an electromechanical device that vibrates at a voltage potential and measures the sensitivity G with PPB - G. The noise is fed gradually into the oscillator and the electrical output characteristics change.

at cut quartz applications