Touch pad using piezo effect

Abstract

The present invention relates to a touch pad, based on piezoelectric effect, that employs a piezo film, is fabricated thin on, but not limited to, metal, exactly and stably recognizes various touch patterns a user executes such as long key, multi key, slide key, etc. and significantly improves the level of security. Disclosed is a touch pad using the piezo effect, including a touch pad equipped with touch keys; a piezo film that attaches to the bottom surface of the touch pad and radiates ultrasonic waves; and a control section that recognizes touches a user executes by analyzing the electric displacement of the piezo film and ultrasonic impedance reflected by the touch pad surface and a touch object that contacts to the surface.

Description

technical field [0001] The present invention relates to a touch panel, and more specifically, to a touch panel capable of using a piezoelectric film while being remarkably slim in a metal material, and capable of accurately and stably recognizing long keys, multi-keys, and swipes performed by a user. Various touch patterns such as keys, and a touchpad that utilizes the piezoelectric effect that can significantly improve the level of security. Background technique [0002] As prior art related to touch-sensitive switches, a (reflection mode ultrasonic) touch-sensitive switch has been developed (refer to US Patent No. 5,673,041): a substrate (substrate) with a touch area, and a piezoelectric element (piezoelectric element) with electrodes , a drive means for applying a drive signal to the electrodes, a detection means for providing a detection signal derived from the drive signal, and a discrimination means for providing an output signal. [0003] This touch-sensitive switch ...

AI Technical Summary

Problems solved by technology

[0006] Therefore, even in the case of preventing the touch area from being easily damaged, improving the reliability of the touch to a certain extent, and gradually increasing the intensity of the touch, the sensitivity of the sensor will not be greatly reduced. On the other hand, the ultrasonic method based on the prior art The touch-sensitive switch has the following fatal disadvantages, that is, touch errors caused by foreign objects such as water or tomato paste

[0007] On the other hand, there is also a problem that in the case of a simple piezoelectric system, it is easy to receive external shocks, vibrations, etc., especially when a piezoelectric element is used for touch recognition, the plate thickness of the metal or the like provided with the touch key If it is thick or the interval between touch keys is narrow, the output value of the piezoelectric element is insufficient, so that accurate and stable touch recognition by the user cannot be guaranteed

[0008] In addition, the prior art piezoelectric touch device using the piezoelectric effect (piezoeffect) cannot be directly applied to metals or new materials without additional process, or even if the touch input is performed on a metal plate with a touch key, if the If the touch object (object) is slowly released, the displacement value of the piezoelectric element cannot be output correctly.

[0009] Therefore, there are problems as follows: long key (longkey) input (key input state is maintained for a certain period of time) and multikey (multikey) input (multikey input state is carried out simultaneously) and wheel slip (wheelslide) touch input (wheelslide) cannot be recognized safely. Use drag (drag) touch and let go of the touch object in a short time)

[0010] Therefore, there is also the following problem: when a touch device utilizing the piezoelectric effect (piezoeffect) is applied to a metal plate or the like, recognition of long key (longkey) input and multikey (multikey) input is limited, and the password that the user can set The types of security keys (securitykey) such as (password) are very limited, and it is actually difficult to expect a high level of confidentiality

[0011] In addition, conventional piezoelectric touch devices utilizing the piezoelectric effect (piezoeffect) cannot be realized in a significantly thinner form when ceramic piezoelectric elements are used, so there is a problem that it is difficult to apply to ultra-thin smartphones and the like.

Images