Touchpad device

1. A touchpad device comprising:

a substrate having a top surface, wherein the top surface is provided with an elastic resilient member, and the elastic resilient member is on a central region of the top surface;

a touch panel disposed above the top surface, wherein the touch panel has an inner surface facing the substrate, the inner surface has a first corner, a second corner, a third corner, and a fourth corner, the first corner is opposite to the third corner, and the second corner is opposite to the fourth corner; and

a balancing assembly disposed between the touch panel and the substrate, wherein the balancing assembly comprises a first balancing bar, a second balancing bar, a third balancing bar, and a fourth balancing bar, two ends of the first balancing bar are respectively adjacent to the elastic resilient member and the first corner, two ends of the second balancing bar are respectively adjacent to the elastic resilient member and the second corner, two ends of the third balancing bar are respectively adjacent to the elastic resilient member and the third corner, and two ends of the fourth balancing bar are respectively adjacent to the elastic resilient member and the fourth corner.

2. The touchpad device according to claim 1 , wherein the inner surface of the touch panel has a first diagonal line and a second diagonal line, the first corner is connected to the third corner through the first diagonal line, the second corner is connected to the fourth corner through the second diagonal line, the first balancing bar has a first end adjacent to the elastic resilient member, the third balancing bar has a third end adjacent to the elastic resilient member, the first end and the third end are at two opposite sides of the elastic resilient member, and the first end and the third end are adjacent to the second diagonal line.

3. The touchpad device according to claim 2 , wherein the fourth balancing bar has a middle point and a fourth end adjacent to the elastic resilient member, and the first end is between the fourth end and the middle point.

4. The touchpad device according to claim 2 , wherein the second balancing bar has a second end adjacent to the elastic resilient member, the fourth balancing bar has a fourth end adjacent to the elastic resilient member, the second end and the fourth end are at the two opposite sides of the elastic resilient member, and the second end and the fourth end are adjacent to the first diagonal line.

5. The touchpad device according to claim 1 , wherein the first balancing bar has a first shaft, the third balancing bar has a third shaft, and the first shaft and the third shaft are parallel to each other.

6. The touchpad device according to claim 5 , wherein the first shaft has a first overlapped region adjacent to the elastic resilient member, the third shaft has a third overlapped region adjacent to the elastic resilient member, the elastic resilient member has a radial direction, the radial direction is perpendicular to the first shaft and the third shaft, the first overlapped region and the elastic resilient member are overlapped with each other along the radial direction, and the third overlapped region and the elastic resilient member are overlapped with each other along the radial direction.

7. The touchpad device according to claim 1 , wherein the second balancing bar has a second shaft, the fourth balancing bar has a fourth shaft, and the second shaft and the fourth shaft are parallel to each other.

8. The touchpad device according to claim 7 , wherein the second shaft has a second overlapped region adjacent to the elastic resilient member, the fourth shaft has a fourth overlapped region adjacent to the elastic resilient member, the elastic resilient member has a radial direction, the radial direction is perpendicular to the second shaft and the fourth shaft, the second overlapped region and the elastic resilient member are overlapped with each other along the radial direction, and the fourth overlapped region and the elastic resilient member are overlapped with each other along the radial direction.

9. The touchpad device according to claim 1 , wherein the first balancing bar has a first end adjacent to the elastic resilient member, the third balancing bar has a third end adjacent to the elastic resilient member, and the first end and the third end overlap with the central region.

10. The touchpad device according to claim 9 , wherein the second balancing bar has a second end adjacent to the elastic resilient member, the fourth balancing bar has a fourth end adjacent to the elastic resilient member, and the second end and the fourth end overlap with the central region.

11. The touchpad device according to claim 1 , wherein the first balancing bar, the second balancing bar, the third balancing bar, and the fourth balancing bar are arranged radially by taking the elastic resilient member as a center.

12. The touchpad device according to claim 1 , wherein the inner surface of the touch panel is provided with an assembling plate, the first balancing bar has a first shaft, the second balancing bar has a second shaft, the third balancing bar has a third shaft, the fourth balancing bar has a fourth shaft, and the first shaft, the second shaft, the third shaft, and the fourth shaft are pivotally connected to the assembling plate.

13. The touchpad device according to claim 1 , wherein the inner surface of the touch panel has a first diagonal line and a second diagonal line, the first corner is connected to the third corner through the first diagonal line, the second corner is connected to the fourth corner through the second diagonal line, the first balancing bar has a first shaft, the second balancing bar has a second shaft, the third balancing bar has a third shaft, the fourth balancing bar has a fourth shaft, the first shaft and the third shaft are parallel to the first diagonal line, and the second shaft and the fourth shaft are parallel to the second diagonal line.

14. The touchpad device according to claim 13 , wherein the first shaft and the first diagonal line are at the same plane, and the plane is perpendicular to the touch panel.

15. The touchpad device according to claim 1 , wherein the first balancing bar has a first shaft and two first side bars, the two first side bars are respectively connected to two opposite ends of the first shaft, the substrate is provided with two assembling members, and the two first side bars are movably assembled to the two assembling members, respectively.

16. The touchpad device according to claim 15 , wherein each of the assembling members comprises a longitudinal plate and a transversal plate, the longitudinal plate is integrally connected to the substrate and has a side portion, the transversal plate integrally extends from the side portion, the transversal plate has a bottom edge, and each of the two first side bars leans against the bottom edge and the side portion.

17. The touchpad device according to claim 15 , wherein an angle between each of the two first side bars and the substrate is in a range between 15 degrees and 45 degrees.

18. The touchpad device according to claim 17 , wherein the angle between each of the two first side bars and the substrate is 45 degrees.

19. The touchpad device according to claim 1 , wherein the balancing assembly comprises a fifth balancing bar and a sixth balancing bar, two ends of the fifth balancing bar are respectively adjacent to the first corner and the second corner, and two ends of the sixth balancing bars are respectively adjacent to the third corner and the fourth corner.