Internally illuminated signs shall be constructed so as to allow the illumination of only letters, numbers or other identifying symbols on the display surface. No light shall pass through the background. External illumination shall be installed so that the light source is not visible from adjoining premises and does not illuminate such premises. No external light source shall be located or arranged so as to cause confusion or a hazard to traffic or conflict with traffic control signals. Flashing signs shall not be permitted. (Ord. 2008-17. Passed 11-17-08.)