Noncontact Bar Code Tag Printer
Original Publication Date: 1974-Nov-01
Included in the Prior Art Database: 2005-Feb-28
Publishing Venue
IBM
Related People
Davenport, DW: AUTHOR [+2]
Abstract
The figure illustrates in a cross-sectional schematic form, a non-contact light-bar generator utilized to form an array of exposed bars on a light-sensitive tag. A source of light 1 impinges on a polarizer filter 2 carried on a glass substrate 3, which has a planar conductive coating of indium or tin oxide which is transparent on the opposite surface 4.
Noncontact Bar Code Tag Printer
The figure illustrates in a cross-sectional schematic form, a non-contact light- bar generator utilized to form an array of exposed bars on a light-sensitive tag. A source of light 1 impinges on a polarizer filter 2 carried on a glass substrate 3, which has a planar conductive coating of indium or tin oxide which is transparent on the opposite surface 4.
The indium oxide planar conductor is connected to an appropriate source such as ground, and the space between the indium oxide layer 4 and the next substrate of glass 5 is filled with a liquid crystal material 6, such as a diester. The glass substrate 5 carries an array of indium oxide or tin oxide transparent conductive bars 7, and the opposite side of glass 5 has another polarizing filter 8.
In operation, a light-sensitive strip of material to receive a bar code pattern such as tag 9, mounted on a suitable carrier strip or paper 10, is placed underneath the bar pattern 7 in the printing array. Light source 1 is energized, and, by suitable program control, individual bars 7 are connected to a suitable source of current.
The electric field produced between the energized bars 7 and the planar indium oxide conductor 4 orients the liquid crystal material 6, to rotate the plane of polarization of the light which has been rotated by the top polarizer 2. The rotation direction is chosen so that, when the liquid crystal material 6 is not in the electric field, polarizer 2 and polarizer 8...