Hall sensor and small magnetic open/close senor: Cellular phone: Introduction of technologies: Asahi Kasei Microdevices Magnetic Sensors

Hall sensor and small magnetic open/close senor

An open/close switch with high durability and reliability and no influence to design

Various detection patterns
of cellular phones

Recently, most of cellular phones are of flip type. When a cellular phone is folded, the magnet on the key approaches the Hall sensor on the display, and the sensor detects a magnetic field and turns off the screen. When a cellular phone is unfolded, the magnet moves away from the sensor making the magnet field weak, and the sensor turns on the screen. The Hall sensor is used in such a non-contact switch.
The Hall sensor can also cover various types of cellular phones such as swivel type, cycloid type, slide type. It prolongs the useful life of batteries for cellular phones, and also serves as a new action switch.

Special features of Hall effect IC for open/close switch application

Asahi Kasei Microdevices has fulfilled a number of requirements to the open/close sensor of cellular phones with our own highly-sensitive and highly-precise Hall sensor technology.

Highly-sensitive sensor

The sensor implements downsizing and weight reduction of the magnet and extends the freedom of allocation distance.

Highly-precise and sensitive characteristic

The position detecting precision can be improved and the design margin can be reduced.

Low current consumption and low voltage drive

The average current consumption is 10 μA. The drive covers a drive voltage of between 5 V and 1.8 V and contributes to longer useful life of the batteries.

Small and thin package

The smallest package in the industry has already been added to the model line. The package complies with higher density of the board mounted and contributes to extend the freedom of allocation distance.

The most extensive lineups in the industry allow to every kinds of detection.

Asahi Kasei Microdevices provides the most extensive lineups in the industry, utilizing the special features of our Hall effect ICs which can determine the magnetic polarity.

South and North pole detection 1 output type … EM1781, etc.
South and North pole detection 2 output type … EM1791
South pole detection 1 output type … EM1771, etc.

>> Application Note > Open/close switch
>> Products > Hall effect IC > Line-up > Switch

Detection pattern examples

Detection pattern example 1

Flip (open/close)

Detection pattern example 1

Detection pattern example 2

Swivel

Detection pattern example 2

Detection pattern example 3

Slide

Detection pattern example 3

Detection pattern example 4

<Open/close and swivel, 2-axis hinge>
Main LCD cycloid
Detecting LCD orientation when enclosure is closed
(Three different statuses can be determined.)
Magnet×1
Sensor×2

Detection pattern example 4

Detection pattern example 5

<Open/close and swivel, 2-axis hinge>
Main LCD cycloid
Detecting LCD orientation when enclosure is closed
(Three different statuses can be determined.)
Magnet×2
Sensor×1(EM-1691)

Detection pattern example 5

Detection pattern example 6

<Open/close and swivel, 2-axis hinge>
Main LCD cycloid
Detecting LCD swivel and open/close of enclosure
(Four different statuses can be determined.)
Magnet×2
Sensor×2(EM-1681)

Detection pattern example 6

Actual records

Cellular phones for Japan, 90 different types and more (as of August 2005)
Many for Asia (Korea, China), etc.