In our daily life, we often see a very strange phenomenon on some machines, that is, there are no key switches on the entire machine. When you touch a hidden area, or touch a location with characters or patterns, the machine is turns on. At this time, the name and location of the luminous buttons will be displayed on the surface. It is very beautiful, and it also looks particularly mysterious and has a strong sense of technology.



The surface key area of this type of product is made of ABS or PC plastic shell, or a whole piece of PMMA acrylic panel, or a whole piece of tempered glass panel, and the buttons with character patterns are made into a translucent effect. When the machine is turned off, the LED inside the machine does not emit light, the machine is dark inside, and the characters or patterns on the panel cannot be seen from the outside. When turned on, the LED emits light from the inside, and the light is emitted from the position of the characters or patterns, while other positions are opaque, thereby displaying the complete keys.

A printed FPC flexible capacitive touch sensing circuit board is attached to the back of the panel, and the functions of all buttons are transmitted through this flexible circuit board. Each button has a wire running from the main circuit board to the button area. The button is similar to one electrode of a capacitor, and the other electrode is connected to the main circuit board IC. When a finger approaches a button from a distance and then touches the button, the IC can sense this change and know which button the finger touched, and then issue corresponding instructions to make the machine work.



Capacitive touch key switches can penetrate insulating material shells within 8mm, including but not limited to ABS, PC, PMMA, glass and other materials. Accurately detect effective finger touches and ensure the sensitivity, stability and reliability of the product. Because touch buttons do not require drilling on the product casing like traditional buttons, the sealing and waterproof and dustproof performance of this kind of switch are better than traditional buttons. Also because there is no mechanical movement of traditional mechanical switches, touch key switches have no friction loss, perform better in terms of sensitivity, stability and reliability, have a longer service life than ordinary mechanical switches, and have low maintenance costs in the future.

Capacitive touch sensing proximity switches have been widely used in audio panels, telephone control keyboards, instrument control panels, washing machine control panels, intelligent access control system control panels, various small household appliance panels (such as induction cookers, disinfection cabinets, microwave ovens) and other products. Covering almost all application fields involving control button operation panels such as household appliances, handheld devices, industrial control, automotive electronics, military products, etc.



Rechan Electronic Technology Co., Ltd. is a manufacturer of capacitive and resistive touch sensing proximity switches. The company has advanced technical experience and a professional design team, as well as a high-quality and mature production workshop. It has performed well in the fields of membrane switches, control panels, touch sensor switches, medical electrodes, etc. Welcome to come to the factory to discuss customization. Email: kevin@rechan.com
 

As electronic technology becomes more and more developed, touch screens and touch-sensitive switches have gradually replaced ordinary traditional mechanical switches. After powering on, as long as your finger touches the button sensing area, the switch command will be triggered to make the machine work. But if there is grease on our hands, fingerprints will remain on the key panel over time. Will such fingerprints directly cause the machine to automatically start up? The answer is no, of course not!



Touch-sensitive proximity switches can be divided into resistive touch switches and capacitive touch-sensitive switches. The principle of a resistive touch switch is actually the same as that of a traditional mechanical switch. When pressed, the two contacts conduct, and the current passes through the printed soft circuit to form a closed loop. After receiving it, the CPU issues instructions to make the machine work, and the contacts are automatically disconnected after the finger leaves.

It's just that the touch switch makes the two contacts very close and the stroke is very short, so the key area can be turned on with just a light touch. The fingerprint left on the surface of the key has no pressure on the key, so it has no effect.



The working principle of capacitive touch sensing switches is completely different from resistive switches. The biggest difference is that each button has only one wire connected to the motherboard PCB and does not require a closed loop. The button is equivalent to one capacitor pole of the capacitor, and the other capacitor pole is connected to the IC on the PCB circuit board. When a finger approaches a button from a distance and then touches the button, the entire process will cause the dielectric constant of the capacitor to change. When the IC senses this change, it will know which button was touched and give corresponding instructions to make the machine work. Similarly, fingerprints on the surface of the keys will not cause changes in capacitance and will not trigger the switch function.



Rechan Electronic Technology Co., Ltd. is a manufacturer specializing in the production of capacitive touch sensing proximity switch circuits. The company has an advanced technical team and many years of experience in membrane switch and touch switch design. Use high-quality PET or imported diffusion film and other raw materials, screen-print transparent conductive oil, silver paste, carbon paste, UV, 3M glue, etc. 

It is attached to the PC or PMMA acrylic panel on the surface, and the other end is connected to the motherboard PCB with FPC to form a capacitive touch sensing proximity switch. kevin@rechan.com
 

Screen-printed products have thick ink and bright colors, so they have always had an irreplaceable position in the printing industry. With technological upgrades in recent years, precision has improved and printing positions have become more accurate. We have added a large number of large-area screen printing machines, roll-to-roll fully automatic screen printing machines. It has laid a better and solid foundation for the quality of membrane switches, capacitive touch sensing switches, FPC flexible circuits and other products. But no matter how the technology is upgraded, its basic principles and operating methods remain the same, which can be roughly summarized as the following points:



1. Choose the mesh of the silk screen according to different materials.
Different printing products require different screens, such as synthetic fiber mesh, stainless steel mesh, natural fiber screen, etc. Various wire meshes are also divided into 50T, 100T, 120T, etc. due to different mesh aperture sizes. The larger the mesh number, the less the amount of ink that flows down, and the printed fonts are clearer. On the contrary, the smaller the mesh number, the more ink will be printed, and the printed color will be thicker.

2. Screen frame
Square screen frame, generally made of aluminum alloy, is similar to a square frame and is used to fix the wire mesh in the middle. The size of the screen frame is selected based on the size of the printed pattern. The larger the screen frame, the wider the printable area and the larger the size of the printed membrane switch panel.

3. Printing screen production
It is the process of fixing the mesh into the mesh frame. First, use equipment to flatten the mesh. It is required that the pulled out mesh has uniform tension and the warp and weft are vertical. Apply glue to the edge of the screen frame, and then fix the finished mesh into the screen frame. After the glue dries, the screen plate is ready.



4. Screen exposure
Use photosensitive paste to copy the film pattern onto the screen. First, apply photosensitive paste evenly on the stencil and let it dry. Then put the film and stencil into the exposure machine and expose it with a cold light source. The exposure time is determined by the size of the pattern.

5. Ink preparation
In general product design, not all colors have the corresponding original ink. The color needs to be adjusted according to the actual situation. The prepared ink is compared with the international Pantone color card under different light sources to confirm the color difference before printing to meet the customer's requirements.

6. Printing
Rechan Electronic Technology Co., Ltd. has multiple semi-automatic screen printing machines, large-area screen printing machines, and roll-to-roll fully automatic screen printing machines. Different printing machines are selected for production according to product size and order volume.



Rechan Electronic Technology Co., Ltd. is a manufacturer of capacitive and resistive touch sensing proximity switches. The company has advanced technical experience and a professional design team, as well as a high-quality and mature production workshop. Excellent performance in membrane switches, control panels, light touch switches, medical electrodes and other fields. Welcome to the factory to discuss customization. kevin@rechan.com
 

Medical devices generally refer to hospital electronic equipment testing instruments and home physical therapy, rehabilitation and correction equipment. Because it is used in special places and often needs to be cleaned with liquid, the dustproof, waterproof and antibacterial requirements are higher than those of ordinary electronic equipment. Water and dust will damage the equipment and affect the measurement accuracy. When designing and using a membrane switch control panel, consider using a waterproof ring sealing structure, and use high-viscosity sealant around the entire perimeter of the product. As shown in the figure below, the structure is the penultimate waterproof outer ring. All circuits and shrapnel switches are inside the waterproof ring. The surface is covered with a PET panel. The FPC flexible circuit tail connector is penetrated through the waterproof ring and inserted into the chassis.




You can also just make a PET printed panel, use 3M strong and high-viscosity double-sided tape on the back to stick it on the control handle case, and use bulging buttons to match the mechanical switches, which can also be dust-proof and waterproof. As shown above, the medical device control panel.


Antibacterial ink can be printed on the surface of the membrane switch to reduce the chance of virus cross-infection. Luminous ink can also be printed to accurately identify key switches in dark environments after turning off the lights.


The surface of the membrane switch can also be made with special-shaped convex hulls and convex edges. The touch feel is strong and distinct, making it convenient for people with special groups such as amblyopia or blind people to touch and use.


Display of inpatient medical rehabilitation physiotherapy bed control handle membrane switch panels from DEWERT, LINET, and MEDISA, the top medical device manufacturers in the United States, the United Kingdom, and Germany.

Rechan Electronic Technology Co., Ltd. specializes in the design and production of membrane switch control panels on medical equipment, inpatient rehabilitation physiotherapy beds, and recliner handles. Long-term service to internationally renowned brand medical device sellers. Familiar with the top standards and quality requirements of membrane switches and medical electrodes. The professional team has many years of design experience and provides one-stop service from quotation, design, drawing, proofing, testing, to mass production. kevin@rechan.com
 

Will update later, thanks for visiting!

Will update later, thanks for visiting!