Laser Scribing Of Thin-Film Solar Cell Panel

Abstract

The present invention describes an apparatus ( 100 ) for a first laser scribing (P 1 ) on the front electrode of a thin film solar cell panel and a similar apparatus ( 100 a ) for subsequent laser scribing (P 2 , P 3 ) on the semiconductor layer and semiconductor layer/rear electrode. Before starting scribing process P 1 , the left hand edge or reference line on the left hand edge on a workpiece is aligned substantively parallel to the linear drive ( 140 ) before translating the workpiece on the apparatus ( 100 ). Similarly, the first and second scribed lines (Lp 1 , Lp 2 ) formed during the P 1 and P 2 processes are separately aligned parallel to the linear drive ( 140 ) before starting the relevant process (P 2 , P 3 ). Alternatively, parallelism of the workpiece is carried out for each batch of the workpiece. In both apparatuses ( 100, 100 a ), the laser sources ( 150 ) are mounted on independently motorized axes.

1 . A laser scribing system for manufacture of thin-film solar panel, said system comprising:
 an input section;   an output section;   a processing section between the input and output sections;   grippers associated with a linear drive operable to grip on a workpiece, wherein the linear drive is operable to translate the workpiece between the input and output sections; and   two or more laser sources disposed in a lower part of the processing section such that each laser source is operable to fire a laser beam upwardly through a transparent substrate of the workpiece to scribe the relevant layer of the thin-film solar panel as the workpiece is being translated between the input and output sections, with each laser source being independently operable to index at predetermined pitches after each scribed line is formed so that the relevant thin-film layer is divided into substantively parallel strips, which are electrically isolated one from another,   wherein each laser source is mounted on an independently motorized axes, which allows scribed lines to be calibrated accordingly.   
     
     
         2 . A laser scribing system according to  claim 1 , wherein each laser source is independently indexable by separate ballscrew and associated motor. 
     
     
         3 . A laser scribing system according to  claim 1 , wherein the input section further comprising:
 an input puller and an associated input stop sensor; and   a front stopper and rear stopper, in respect of translation of the workpiece, being associated with the linear drive, and a spring loaded roller operable to biase the workpiece against the front and rear stoppers such that scribed lines formed on the workpiece are parallel to the edge of the workpiece that is in contact with the front and rear stoppers.   
     
     
         4 . A laser scribing system according to  claim 3 , wherein the rear stopper is adjustable through a ballscrew and an associated motor. 
     
     
         5 . A laser scribing system according to  claim 4 , further comprising a camera to monitor the position of the rear stopper. 
     
     
         6 . A laser scribing system according to  claim 1 , further comprising a gantry disposed across both the linear drive and workpiece such that the gantry is substantially above the processing section. 
     
     
         7 . A laser scribing system according to  claim 6 , wherein the gantry further comprising a camera and a suction nozzle associated with each laser source. 
     
     
         8 . A laser scribing system according to  claim 5 , wherein the camera is mounted on an independent motorized axis disposed transverse to the scribed lines. 
     
     
         9 . A laser scribing system according to  claim 1 , wherein the laser sources are mounted on linear guides such that one or more laser sources are slidable during maintenance. 
     
     
         10 . A laser scribing process in the manufacture of thin-film solar panel, the process comprising:
 loading a workpiece with the transparent substrate facing downwards in an input station of a first machine;   biasing a reference edge of the workpiece against a front and rear stopper associated with a linear drive, wherein the linear drive is operable to translate the workpiece between the input station and an output station;   translating the workpiece back and forth between the input station and output station and firing two or more laser beams at a first frequency substantially vertically through a space between the input and output stations to pass through the transparent substrate of the workpiece to scribe parallel lines on the front electrodes with reference to the edge of the workpiece in contact with the front and rear stoppers, wherein each said laser beam is outputted from a separate laser source that is mounted on an independently motorized axes, which allows scribed lines to be calibrated accordingly; and   indexing the two or more laser sources at predetermined pitches and repeating the back and forth translation of the work piece between the input and output stations until the entire front electrode is divided into parallel strips that are electrically isolated one from another.   
     
     
         11 . A laser scribing process according to  claim 10 , further comprising:
 loading the workpiece formed with parallel strips of front electrodes in an input station of a second machine;   biasing the workpiece against a front stopper and a rear adjustable stopper associated with a linear drive similar to that of the first machine, wherein the linear drive is operable to translate the workpiece between the input station and an output station;   aligning a scribed line Lp 1  on the front electrode with the linear drive by using a camera disposed at the front edge of the workpiece and another camera disposed near the rear adjustable stopper to determine the correction required to achieve parallelism;   translating the workpiece back and forth between the input station and output station and firing two or more laser beams at a second frequency substantially vertically through a space between the input and output stations to pass through the transparent substrate of the workpiece to scribe parallel lines (Lp 2 , Lp 3 ) on the semiconductor layer or rear electrode with reference to the scribed lines (Lp 1 ) on the front electrode, wherein each said laser beam is outputted from a separate laser source; and   indexing the two or more laser sources and repeating the back and forth translation of the work piece between the input and output stations until the entire semiconductor layer or rear electrode is divided into parallel strips that are electrically isolated one from another.   
     
     
         12 . A laser scribing process in the manufacture of thin-film solar panel, the process comprising:
 loading a workpiece with the transparent substrate facing downwards in an input station of a machine;   biasing the workpiece against a front stopper and a rear adjustable stopper associated with a linear drive; wherein the linear drive is operable to translate the workpiece between the input station and an output station;   aligning a reference line on a reference edge of the workpiece with the linear drive by using a camera (C 1 -C 4 ) disposed near the front edge of the workpiece and another camera (C 5 ) disposed near the rear adjustable stopper to determine the correction required to achieve parallelism between the reference line and the linear drive;   translating the workpiece back and forth between the input station and output station and firing two or more laser beams at a first frequency substantially vertically, through a space between the input and output stations, through the transparent substrate of the workpiece to scribe parallel lines on the front electrode; wherein each said laser beam is outputted from a separate laser source that is mounted on an independently motorized axes, which allows scribed lines to be calibrated accordingly;   indexing the two or more laser sources at predetermined pitches and repeating the back and forth translation of the work piece between the input and output stations until the entire front electrode is divided into parallel strips that are electrically isolated one from another;   aligning a scribed line (Lp 1 ) on the front electrode with the linear drive by using the camera (C 1 -C 4 ) disposed near the front edge of the workpiece and the another camera (C 5 ) disposed near the rear adjustable stopper to determine the correction required to achieve parallelism;   translating the workpiece back and forth between the input station and Output station and firing two or more laser beams at a second frequency substantially vertically, through a space between the input and output stations, through the transparent substrate of the workpiece to scribe parallel lines (Lp 2 , Lp 3 ) on the semiconductor layer or rear electrode; wherein each said laser beam is outputted from a separate laser source; and   indexing the two or more laser sources and repeating the back and forth translation of the work piece between the input and output stations until the entire semiconductor layer or rear electrode is divided into parallel strips that are electrically isolated one from another.   
     
     
         13 . A laser scribing process according to  claim 12 , wherein parallelism alignment is carried out manually with a dummy workpiece. 
     
     
         14 . A laser scribing process according to  claim 12 , wherein the camera or cameras are mounted on independently motorized axes disposed transverse to the scribed lines and workpiece parallelism alignment is carried out automatically. 
     
     
         15 . A laser scribing process according to  claim 14 , wherein workpiece parallelism alignment and laser source/camera alignment are carried out with a precision jig. 
     
     
         16 . A laser scribing system according to  claim 7 , wherein the camera is mounted on an independent motorized axis disposed transverse to the scribed lines. 
     
     
         17 . A laser scribing process according to  claim 10 , wherein parallelism alignment is carried out manually with a dummy workpiece. 
     
     
         18 . A laser scribing process according to  claim 10 , wherein the camera or cameras are mounted on independently motorized axes disposed transverse to the scribed lines and workpiece parallelism alignment is carried out automatically. 
     
     
         19 . A laser scribing process according to  claim 18 , wherein workpiece parallelism alignment and laser source/camera alignment are carried out with a precision jig.