Electromagnetic energy interference seal for light beam touch panels

An electromagnetic energy interference seal for light beam touch panel systems having a matrix of crossed light beams formed by pairs of opposing light beam sources and light beam detectors used to establish the position of an object inserted into that matrix, said matrix having a periphery comprising:

• an electrically conductive member disposed at the periphery of the matrix of crossed light beams and having a plurality of spaced apart apertures formed therethrough;
• the plurality of apertures being disposed in the member such that there are two apertures in optical alignment with each light beam, one aperture being disposed adjacent a light beam source and the second aperture being disposed adjacent the paired light beam detector;
• the apertures having a cross-sectional size to length ratio selected so that they act as waveguides having a cutoff frequency which is lower than the frequency of the passing light beams and is higher than the frequency of electromagnetic energy interference;
• and
• environmental sealing means disposed across the apertures for sealing the apertures from environmental contaminants.

An electromagnetic energy interference seal for light beam touch panel systems having a matrix of crossed light beams formed by pairs of opposing light beam sources and light beam detectors used to establish the position of an object inserted into said matrix, said matrix having a periphery comprising:

• an electrically conductive member disposed at the periphery of the matrix of crossed light beams and having a plurality of spaced apart apertures formed therethrough;
• the plurality of apertures being disposed in the member such that there are two apertures in optical alignment with each light beam, one aperture being disposed adjacent a light beam source and the second aperture being disposed adjacent the paired light beam detector;
• the apertures having a circular cross-section and having a length which is approximately four times their diameter whereby the apertures act as waveguides having a cutoff frequency below the frequency of the light beams but above the frequency of electromagnetic energy interference;
• a first cover of a dark color which is disposed over the external openings of the apertures to seal the apertures from environmental contaminants while substantially passing the light beams without attenuation;
• and
• a second cover which is disposed over the internal openings of the apertures to seal the apertures from environmental contaminants while substantially passing the light beams without attenuation.

Electromagnetic energy interference sealing apparatus for a light beam touch panel system having a matrix of crossed light beams formed in front of the face of a display device by pairs of opposing light beam sources and light beam detectors used to establish the position of an object inserted into said matrix, the sorces and detectors being arrayed around the periphery of the display device, the sealing apparatus being used for sealing of the system including the display device, sources and detectors, the sealing apparatus comprising:

• an electromagnetic interference sealing means including an embedded conductive mesh across the face of said display device;
• means including a bezel enclosing said display device;
• an electrically conductive strip disposed about said periphery between said bezel and said sealing means and having a plurality of spaced apart aperture means formed therethrough which are disposed in optical alignment with the light beams for passing the light beams therethrough;
• the aperture means each having a cross-section size-to-length ratio selected so that each said aperture means acts as a waveguide having a cutoff frequency which is lower than the frequency of the passing light beams and is higher than the frequency of electromagnetic energy interference;
• means for electrically connecting said wire mesh to said conductive strip;
• and
• environmental sealing means disposed across each said aperture means for sealing each said aperture means for environmental contaminants.