Generally, the classification of desktop keyboards can be classified according to the number of keystrokes, the working principle of the keys, and the appearance of the keyboard. There are many types of keyboards. Generally, they can be divided into three types: contact type, non-contact type and laser type (laser laser keyboard). The former uses metal to connect or disconnect two contacts to input signals, and the latter The input signal is generated by means of Hall effect switches (using magnetic field changes) and capacitive switches (using current and voltage changes).
According to code points
From the function of coding, the keyboard can be divided into two types: fully coded keyboard and non-coded keyboard.
The full coded keyboard is the hardware to complete the keyboard recognition function, it by identifying whether the key is pressed and the position of the pressed key, the full coding circuit generates a corresponding code information (such as ASCII code). The non-coding keyboard is the software to complete the keyboard recognition function, it uses simple hardware and a set of special keyboard coding program to recognize the position of the key, and then the CPU converts the position code into the corresponding code information through the table lookup program. The speed of the non-coding keyboard is low, but the structure is simple, and the software can provide great convenience for the redefinition of some keys.
According to the application, it can be divided into seven categories: desktop keyboards, laptop keyboards, mobile phone keyboards, industrial computer keyboards, speed recorder keyboards, dual-control keyboards, and ultra-thin keyboards.
According to the nature of the code element
According to the nature of the code element, it can be divided into two categories: alphabetical keyboard and numeric keyboard.
According to the working principle
1. Mechanical keyboard (Mechanical) uses a similar metal contact switch. The working principle is to make the contacts on or off. It has the characteristics of simple technology, high noise, easy maintenance, strong rhythm when typing, and will not change the hand feeling after long-term use.
2. Plastic membrane keyboard (Membrane) keyboard is divided into four layers in total, realizing no mechanical abrasion. Its characteristics are low price, low noise and low cost, but after long-term use, the hand feel will change due to material problems. Has occupied most of the market share.
3. Conductive rubber keyboard (Conductive Rubber) contact structure is connected by conductive rubber. There is a layer of conductive rubber with conductive bumps inside the keyboard. Each button corresponds to a bump. When pressed, the contacts below are connected. This type of keyboard is a transitional product from a mechanical keyboard to a membrane keyboard in the market.
4. Capacitives without contact use a principle similar to capacitive switches. Changing the distance between the electrodes when pressing the keys causes the capacitance to change to drive the encoder. It is characterized by no wear and good sealing.
Enter points by text
The number of keystrokes that can be pressed at the same time according to text input can be divided into single-key input keyboard, double-key input keyboard and multi-key input keyboard. The commonly used keyboards belong to single-key input keyboards, and the shorthand keyboard belongs to multi-key input keyboards, the latest ones appearing. The four-section input method keyboard is a two-key input keyboard.
According to the regular points
Conventional keyboards have mechanical keys and capacitive keys. In the industrial computer keyboard, there is also a keyboard that touches the membrane keys. Mechanical keyboard is the first structure to be adopted. Generally, it is similar to the principle of contact switch to make the contacts turn on or off. It has the characteristics of simple technology, convenient maintenance, general feel, high noise, and easy to wear. Most of the cheap mechanical keyboards The copper spring is used as the elastic material, and the copper is easy to fold and lose its elasticity, and the failure rate increases over time. The capacitive keyboard. It is a keyboard based on a capacitive switch. The principle is to change the distance between the electrodes by pressing the keys to produce a change in capacitance, temporarily forming a condition for allowing the oscillating pulse to pass. Theoretically, this kind of switch is non-contact and non-contact type, the wear rate is very small or even negligible, and there is no hidden danger of poor contact. It has low noise, easy to control the feel, and can produce high-quality keyboards, but the process is more mechanical. complex structure. There is also a keyboard for industrial computer, which adopts light-touch membrane keys in order to be completely sealed, which is only suitable for special occasions.
According to the shape
The appearance of the keyboard is divided into a standard keyboard and an ergonomic keyboard.