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Silicon rubber keypads and their types: (Rubber Switches Beginner Guide)

Dec 16, 2020

Major Applications of Rubber Switches

Silicon rubber keypads have become trending and crucial for the engineers and business owners. As other keypads contain the plastic or other materials, they contain silicon rubber. The silicon rubber provides the softness and elasticity to these keypads. That is why they have another name, elastomeric keypads.

Due to their soft and unique characteristics, they have several benefits over the other keypads. Therefore, these keypads are the best and popular choice for the business owners and industries. This article will provide you with the details and information necessary about the silicon rubber keypads.

Silicon rubber keypads

Silicon rubber keypads Composition

The composition of the silicon rubber keypads may vary according to the design of the keypads. The common thing about their structure is the materials used in the structure. This material is silicon rubber around the electronic switch, present at the midpoint. This silicon rubber material contains the conductive material at the bottom.

This conductive material may be gold or other metal. There is an inert gas below this conductive material. After the pocket of air, there is a switch contact. When we press the key on the keypad, the silicon material deforms its shape. During this, the conductive material becomes in direct contact with the switch contact.

Silicon rubber keypads Applications

The silicon rubber keypads provide the tactile feedback mechanism to the users. When the user presses the key, the silicon rubber deforms itself. When the user releases the key, the button pops up back. This tactile feedback tells the user that the command is successfully registered.

The advantage of the silicon rubber keypads is that they are soft and elastic to use. As compared to the other materials that are hard and non-elastic to use, they are easy to use. Therefore, they are comfortable and easy for the users.

The fundamental benefit of these keypads is that they are not vulnerable to the diverse and extreme conditions. They don’t lose their function in the undefined conditions of temperature.

The temperature extremes don’t damage these keypads as to other keypads made of hard materials. This property makes them the best choice in the areas where heat is produced excessively like factories and assembly lines.

As the silicon keypads provide the tactile feedback, it helps the users prevent the errors. This feedback increases the accuracy of the typing and prevents the false typing by providing the tactile feedback. In this way, tactile feedback confirms the user about the registration of the command.

The keypads may consist of other materials like plastics. But the tactile feedback and softness is the characteristic of the silicon rubber material. Other materials are hard and difficult to use. Therefore, silicon rubber keypads are best choice for the mechanical engineers and business owners.

Silicon rubber keypads Types

The silicon rubber keypads come in two fundamental forms. These are conductive and non-conductive silicon rubber keypads. The conductive silicon rubber keypads have the pill of conductive material in the structure. While the non-conductive silicon rubber keypads have the metal dome switch.

The term silicon rubber keypad may have two meanings in it. It can refer to the whole keypad or the silicon rubber part of the keypad. If it refers to the whole silicon rubber keypad, it also includes the printed circuit board (PCB). However, the molded rubber part of the silicon rubber keypad is a component of the keypad assembly.

The silicon rubber keypads are the unique component of the molded silicon rubber material that inserts the key tops. However, there is a network of molded rubber between the key tops and the base mat. The base mat is present at against position of the printed circuit board. The key tops are inserted on the base mat.

The process for the manufacturing of the rubber keypads is the low pressure compression method. While another method is also there for their manufacturing. This is the high pressure liquid injection method. These silicon rubber keypads may have the solid color or translucent. They may also contain the mixture of the solid and translucent colors.

The key tops of the silicon rubber keypads from the front surface have the coating of the material that is resistant to wear. For this purpose, the materials like gloss or matte are significant for the coating. However, the coating of the key tops does not affect the internal design of the silicon rubber keypads.

Silicon rubber keypads 2021

Conductive rubber keypads

The conductive rubber keypads have the pill of the conductive material present in the centre. This conductive material contains the carbon and silicon rubber. The function of the carbon particles is in the conduction. While the silicon rubber material holds the carbon particles in the position. The pill of the conductive material had the attachment and connection with the bottom part of the silicon keypad.

When we press the key top, the rubber keypads form an electrical switch closure. At the same time, the puck of the conductive material makes a contact with the inter-digitated conductor. The switch closure form at the end of the key top and the puck surface becomes parallel to the printed circuit board surface.

The conductive rubber keypads are also able to provide the feedback to the users. But the procedure for their feedback is somewhat different. These keypads give feedback by force cone. The force cone establishes between the key tops and the base. The support and protection of the key tops is the activity of the force cone.

The process of tactile feedback starts when we press the key top. The force cone compresses to the extent and then collapses. This process provides the tactile feedback to the user. For this purpose, the force cone has sufficient amount of rubber in order to provide the flexibility and durability.

Non-conductive rubber keypads

The physical appearance of the non-conductive rubber keypads may be similar to the conductive rubber keypads. But there is a difference in the internal structure of these two. The non-conductive rubber keypads have the metal dome switch inside them.

The pill or puck of the semi-conductive material is absent in these keypads. Moreover, the tactile feedback is not produced by the force cone. The metal dome switch has the function of tactile feedback in these keypads. There is a mixture of the thick substances between the key tops and the base. In this way, they are not sensitive to the tearing and cracking.

Here, the key top moves but there are not restrictions that were present in the conductive rubber keypads. In addition, the durometer of the non-conductive silicon rubber keypads is firmer than those of conductive keypads. This provides the firmer feedback to the user.

Silicon rubber keypads Switch sealing

Switch cavity is the point where the two switches contact each other. Around these contacts there is air volume boundary. In the case of conductive rubber keypads, the sealing of the switch contacts does not occur.

The reason is that during pressing the key, the volume of air should move freely. Many new features can be incorporated in these keypads in order to avoid the damage and destruction of the external part. But the sealing of switches does not occur. The volume of the air is present around the two contacts of the switches at the switch cavity.

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