- silicone keypad
The silicone rubber keypads are the most common form of changing the technology of today. They offer reliability, durability and design flexibility. There are some simple rules and basic design elements to consider when designing a keyboard silicon rubber.
- silicone keypad
Key design will vary with the functional and aesthetic needs of the application. E ‘can form a key in almost any shape and to fit almost any configuration. It ‘important to remember that the key shape will affect the feel of the key. While a circular-shaped key standard will look across the surface of a half moon-shaped key answer different depending on where you press the button.
- silicone keypad
Once you have decided on a key figure and presentation, the next item to consider is the method to mark the tire and the creation of legends. There are three common methods for the marking of keyboards, printing, laser engraving, plastic caps and key.
Print
The press is the most common method of marking rubber. Rubber is fixtured to flatten the top button then screen printed. There is no limit to the number of colors available. The arc of the first key determines the extent to which the press must be reported by the edge of the key.
- silicone keypad
Currently there are several options available to improve the life the legend with the molded rubber.
Or plastic key caps – custom printed clear plastic is adhered over the legend or molded rubber
or oil or epoxy coating – coating is deposited on the upper surface of the button press, available in matte, semigloss or gloss
Drip or coating – coating flow can be hard or flexible. It adds a layer of gloss over the top key. Can not be used on some buttons with sharp angles. hard coatings are subject to cracking if the key has large areas.
O Parylene Coating – provides the highest level of protection for a non-coated plastic. Parylene bond to rubber at the molecular level.
- silicone keypad
Laser engraving
Laser engraving is particularly suited for applications where the keyboard is backlit. Etching typically involves three stages of production.
1) translucent rubber (any color) is sprayed with a clear ink base layer, which will be the color legend that is visible to the user.
2) The rubber ink is sprayed with a matte finish that will be the overall color of the keyboard.
3) The top coat of ink is etched away using laser engravers at high speed to reveal the basecoat.
Alternatively, you may want to use a single ink rubber transparent or opaque and laser etch the legends that reveal the color of the rubber that is used.
Plastic caps key
The longest duration of such legend is custom molded plastic. legends of plastic is not consumed. Many keyboards of mobile phones are designed with plastic buttons made of rubber.
Functional Design Considerations
Report Snap & tactile
The ratio determines the click of a keyboard tactile sensation experienced by the user. The report recommended shooting for designers to maintain 40% -60%, in case of fall below 40% will lose the keys feel, but they have a higher life. Loss of tactile sensation means that you will not receive feedback ‘click’ start-ups.
Snap ratio is calculated by taking the [Implementation Force (F1) - CONTACT FORCE (F2)] / Implementation Force (F1).
Most customers are not web design and to contact the manufacturer to design and meet the requirements.
- silicone keypad
Action to reduce rocking
A common problem with the design of the rubber keyboard is the oscillation that can occur when a key is pressed. rocking action can reduce the length of the keyboard, make it difficult to implement for the user, and cause other problems. The following tips will help reduce this problem.
Add messages or stabilization on the basis of the main
Maintain or 0.8 mm key stroke as close as possible
o Keep the length to a minimum web
Keeping corner or near 40 ° web
Implementation Force or 80-150 grams for keys of 10-15 mm in height and 150-175 grams for the key 15-25mm high
Return force should be set at 30-35 grams to ensure that the keys do not stick.
Switch Life
The web design and the hardness of rubber are the two factors that most influence longevity keyboard. The design should reduce the stress on the rubber if long life is desired. Using silicone durometer higher, increasing the driving force, or increasing the race will all shorten the life keyboards.
- silicone keypad
Rubber hardness
hardness of rubber for a keyboard can vary between 30 and 70 durometer (Shore A). Generally, the fingerboards are between 40 and 60 durometer.
Minimum height of key
For any design, calculate the minimum height of the key, as follows, Base Keypad bezel thickness thickness + Key + race + 0.5 mm.
Contact
The pill is the contact of carbon more common because of his long life (> 10 million donations) and low resistance (Printed Circuit Board Design
The rubber contacts need to come into contact with a circuit below. rubber key mats themselves are very reliable in operation. However, when considering a PCB design, the environment in which the keyboards are used should be considered to ensure that the switching unit is fully reliable. mum of 1.25 times.
Flexible Printed Circuit Design
Rubber keypads are typically used with printed circuit boards. However, many rubber keypads are also used with flexible printed circuits. flexible circuits can be polyester or copper (Kapton).
