controller 23 also can control the probe 22 to move along the reverse direction of b 1 to retract the probe 22 backward in the holder 21 the direction b 1 is the direction that the probe 22 is inserted into the glass substrate not shown for inspection please refer to fig3 which shows a structure diagram of the stretch controller 23 in fig2 the stretch controller 23 comprises a movable control base 231 a stretch control component 233 and a retract control component 232 the movable control base 231 is fixedly connected with the probe 22 please refer to fig3 the stretch control component 233 comprises a first electromagnetic component 234 and a second electromagnetic component 235 the first electromagnetic component 234 is positioned on the movable control base 231 and the second electromagnetic component is positioned on the holder 21 in an exemplary embodiment the stretch control component 233 can be other structures as long as the structure is capable of moving the probe 22 with a predetermined distance d along the direction b 1 as the probes 22 are moved with the predetermined distance d along the direction b 1 the probes 22 are inserted into the glass substrate in the embodiment shown in fig2 the retract control component 232 is an elastic element and preferable a spring structure other structure also can be considered as long as the structure can move the probe 22 with the predetermined distance d along the reverse direction b 2 of the direction b 1 the top cover 24 is employed for holding the wires 25 a control circuit not shown inputs or not inputs of an electrical signal to the wires 25 the wires 25 are electrically connected to the first electromagnetic components 234 after.