Analog pointing device (APD)

Recently, there has been a growing demand for an input device that offers high operability to match advances in the functions and multi−functions of electronic equipment. “Highly operable input device” refers to the kind of device that can emulate certain human senses, i.e., an input device that has an analog output. Here, we introduce analog pointing devices (hereinafter called APDs) that use Hall sensors, to enable free movement of the cursor on screens for cellular phones, etc.

APD using Hall sensor

• Analog output of displacement of the input key and high operability can be obtained.
• Small, thin construction of the control element can be achieved.
• Durability is improved due to the non−contact detection process.
• Because magnetism is detected, the device is more resistant to tiny particles of dirt, dust, or oil.

Principle

The magnetic field produced by a magnet that is integrated with the moving element is detected by four Hall elements, and the position of the magnet is computed from the difference in magnetic flux density detected in two dimensions.

Example of composition

Here are two typical examples of composition of APDs using Hall sensors.

This example comprises a Hall effect IC integrating four Hall elements and a control IC in one package and the magnet. Four Hall elements can be installed without risk of misalignment because they are embedded in one package.

This example consists of four Hall elements that detect magnetic fields on a plane (X and Y coordinates), a control IC, and a one−ring magnet magnetized in the radial direction.
By increasing the degree of freedom in the arrangement of the four Hall elements and the control IC the mechanism can be made thinner.

Recommended products for application

We can supply the following products for use in constructing APDs:

List of applications

Cellular phones, etc.