Force sensor with high impact resistance designed for stylus pens

These days, electronic blackboards and tablets are being used on several occasions, such as school sessions and company meetings. Therefore, demand for pen-shaped devices (stylus pen), which are mostly used for the purpose of working creatively - including digital drawing and painting - has been growing.

Stylus pens, or styli, contain force sensors that trace the trajectory of the pen tip and then reproduce different thicknesses in the artwork corresponding to the pressure applied. Styli require a sensor with high resolution and linearity, but also need to be sturdy enough to not break when the pen is unintentionally dropped.

The HSFPAR004A lives up to these requirements because it maintains the features of already existing products for high linearity (<2%FS), high resolution (detects micro force with less than 0.01N), and small size of 2.00x1.60x0.66mm, while at the same time realising an improvement in impact resistance of up to 55N.

The sensor offers an operating life of 1,000,000 cycles and is resistant to external magnetic and electric fields. Besides its use in input devices, the sensor is suitable for industrial machines handling precision equipment and a range of diverse applications, especially on the grip parts of robot arms for precision grip force adjustments.

Key features

• High impact resistance proved by a breaking load of 55N
• Detects micro force of less than 0.01N
• Long operating life of more than one million cycles
• Resistant to external magnetic fields and electric fields

The improved impact resistance of the sensor is achieved with the extension of the actuator diameter of the sensing zone from the existing 0.20 to the new 0.40mm, while at the same time keeping the rounded peripheral edge to disperse impacts.

Therefore, the breakage risk of the sensor in stylus pens is reduced in case the pen is unintentionally dropped, while still guaranteeing smooth pen pressure expression without spoiling the easy integration into end products. Mass production has been underway since March.