Touch panel device and electronic device with improved haptic feedback
A touch panel device, includes a transparent protective substrate disposed on a front side of the touch panel, the protective substrate being configured by joining a first glass substrate residing on a front side and a second glass substrate residing on a touch panel side, wherein either one of the first and second glass substrates is configured to have one or more stepped portions formed either on a rear surface of the first glass substrate or a front surface of the second glass substrate, the rear surface of the first glass substrate and the front surface of the second glass substrate facing one another; and one or more piezo vibration elements each disposed within one of the stepped portions so as to be acoustically coupled with the first glass substrate, wherein each of said one or more stepped portions is configured thicker than the corresponding piezo vibration element.
1. A touch panel device, comprising:
a touch panel;
a display unit disposed on a rear side of the touch panel so that the touch panel is above the display unit as seen from a side of a user;
a transparent protective substrate disposed on a front side of the touch panel so that the transparent protective substrate is above the touch panel as seen from the side of the user, the protective substrate being configured by joining a first glass substrate residing on a front side and a second glass substrate residing on a touch panel side, wherein either one of the first and second glass substrates is configured to have one or more stepped portions formed either on a rear surface of the first glass substrate or a front surface of the second glass substrate, the rear surface of the first glass substrate and the front surface of the second glass substrate fixed side by side facing one another so that said one or more stepped portions are embedded in the transparent protective substrate;
one or more piezo vibration elements each disposed within one of the stepped portions in the transparent protective substrate so as to be acoustically coupled with the first glass substrate of the transparent protective substrate, the one or more piezo vibration elements thereby being disposed in the transparent protective substrate,
wherein each of said one or more stepped portions is configured thicker than the corresponding piezo vibration element.
2. The touch panel device of claim 1 , wherein at least one of the piezo vibration elements includes a plurality of piezoelectric layers and a plurality of electrode layers laminated in an alternate manner.
3. The touch panel device of claim 1 , wherein at least one of the piezo vibration elements has a bimorph structure.
4. The touch panel device of claim 1 , wherein each of vibrations generated by the piezo vibration elements is conveyed to the first glass substrate in a form of a surface elastic wave.
5. An electronic device, comprising a touch panel device of claim 1 .
6. The touch panel device of claim 1 , wherein at least one of the stepped portions is formed on the second glass substrate.
7. The touch panel device of claim 6 , wherein at least one of the stepped portions is formed as a through-hole.
8. The touch panel device of claim 7 , further comprising one or more buffers each disposed between one of the piezo vibration elements and the touch panel.
9. The touch panel device of claim 6 , wherein the first glass substrate is configured thinner than the second glass substrate.
10. The touch panel device of claim 6 , wherein the at least one of the stepped portions is formed to have a tapered wall configured such that a cross section of said at least one of the stepped portions becomes wider as approaching the first glass substrate.