Method and device for exposing both sides of a sheet
AssigneeManiaBarco N.V.
InventorsMarc Vernackt, Ronny A. De Loor, Anne-Marie F. Empsten, Mark Ryvkin
Life of this patent
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Abstract
A device is described for exposing both sides of a light sensitive sheet such as a printed circuit board panel according to imaging data. The device comprises an optical system for scanning the sensitive sheet by one or more beams. The optical system scans both sides with the scan lines on one side mutually positioned with respect to the scan lines on the other side. According to one implementation, the optical system includes two optical scanning units driven by a single source, with a switch alternating the beam from the source to one then the other optical scanning unit.
Claims78
An apparatus for exposing both sides of a sheet with one or more optical beams, the apparatus comprising:
- (a) a carrier for fixing the sheet thereto;
- (b) an optical system to generating one or more moving light beams onto each side of the sheet, each light beam forming a scan line on a surface of the sheet in a scan line direction relative to the sheet;
- (c) a drive system to generate relative motion between any point on any scan line on the sheet and the sheet in a transverse direction, the transverse direction substantially transverse to the scan line direction, the drive system configured to enable each light beam to trace on each side a set of one or more substantially parallel scan lines in the scan line direction, each scan line of the set of scan lines mutually separated in the transverse direction, the sets of scan lines covering a desired region on the side of the sheet;
- and
- (d) a mutual-positioning mechanism coupled to the optical system to accurately position the sets of scan lines on one side of the sheet relative to the sets of scan lines on the other side of the sheet.
An apparatus for exposing both sides of a light sensitive sheet according to imaging data, the imaging data including a first side's imaging data for exposing a first side of the sheet and a second side's imaging data for exposing the side other than the first, the apparatus comprising:
- (a) carrier for fixing the sheet thereto
- (b) an optical system for exposing the first side's imaging data onto a first desired region on the first side of the sheet and the second side's imaging data onto a second desired region on the other side of the sheet;
- and
- (c) a mutual-positioning mechanism to accurately position the first side's imaging data on the first side relative to the second side's imaging data on the other side of the sheet, the mutual-positioning mechanism active during the exposing of the sides by the optical system.
An optical detection module for measuring the cross-scan position of a moving optical beam in a scanning apparatus, the beam moving in an in-beam direction, the detection module comprising:
- (a) a first photo-detector cell having a front edge and a back edge transverse to the in-beam direction;
- (b) a second photo-detector cell adjacent to the first cell in the in-beam direction and having a front edge and a back edge transverse to the in-beam direction, the second cell front edge and the first cell back edge adapted to fit together and mutually adjacent to form a first interface between the first cell and the second cell,
- (c) one or more preamplifiers coupled to the photo-detector cells to measure the response to light traversing the cell, the one or more preamplifier outputs processed to generate a detection module output dependent on the cross-scan position,
- the two cells positioned such that the moving beam first hits the first cell front surface, then crosses the interface, and then crosses the second cell back surface,
- the first and second cell front and back surfaces shaped such that the relative amount of time the beam traverses each of the cells is indicative of the cross-scan position of the beam,
- whereby the accuracy of the detection module output is substantially independent of the focus of the beam.
A method for exposing both sides of a sheet with optical beams the method comprising:
- (a) scanning each side of the sheet with one or more moving light beams, each moving light generating a scan line in a scan line direction;
- (b) generating relative motion between the sheet and the scan lines in a direction transverse to the scan line direction,
- wherein the scan lines on one side are accurately positioned relative to the scan lines of the other side of the sheet.
A method for scanning both sides of a light sensitive sheet,
- (a) fixing the sheet to a carrier
- (b) presenting one side of the sheet to an optical scanning unit, and exposing the one side;
- (b) presenting the side other than the one side to the optical scanning unit, and exposing the other side,
- the sheet remaining in the carrier until both sides have been exposed by the optical scanning unit such that the exposure of one side is accurately positioned relative to the exposure of the other side.
A method for exposing both sides of a PCB panel according to imaging data, the method comprising:
- (a) simultaneously generating scan lines on both side of the sheet, the scan lines modulated by the imaging data;
- and
- (b) holding the sheet in an upright position during scanning.
An apparatus for exposing both sides of a light sensitive sheet according to imaging data, the apparatus comprising:
- an optical system for scanning the sensitive sheet by one or more beams, the optical system including two optical scanning units, each for scanning one side of the sheet by one or more light beams modulated according the imaging data.
Dependencies are inferred from the claim text.