VIEWING AND IMAGING SYSTEMS

摘要

A viewing and imaging system is provided for use in a screen printer. Light is supplied to the screen and/or the board from a number of independently controller light sources. According to one aspect of the invention, one light source provides substantially collimated light and another light source provides diffuse light. The light sources are controlled by a controller that pulses the light sources in order to provide a stroboscopic image of the board and screen. The duration of the pulses is adjusted to adjust the effective brightness of the light sources. The timing of the pulses are adjusted so that the temporal midpoints of pulses from each of the light sources are coincident.