Android Object Drag With Touch Problem

So, as the title says, i have a problem with moving/darging and object with touch... I was actually succesful at draging the object BUT the thing is, when i drag the object, it doesn't quite have the same position as the touch position...

To be more specific and less confusing xD heres an image of the example :P

I have the script attached to the object i want to drag, and this happens:

This is the Script I attached to the object:

 using UnityEngine;
 using System.Collections;
 
 public class ButtonMover : MonoBehaviour {
 
     //FixedUpdate is called once per fixed time step
     void FixedUpdate()
     {
         if (Input.touchCount > 0) {
             Vector3 _deltaPosition = Input.GetTouch (0).deltaPosition;
 
             switch(Input.GetTouch (0).phase)
             {
             case TouchPhase.Began:
                     break;
 
             case TouchPhase.Moved:
                 Drag (_deltaPosition);
                     break;
 
             case TouchPhase.Ended:
                 break;
                 
 
             
             }
                 } else {
 
                 }
     }
 
     void Drag(Vector3 _deltaPosition)
     {
         this.transform.localPosition = new Vector3(_deltaPosition.x, 0, 0);
     }
 
 
 }

Pweeseee Hewp Meeee :3?