Diffuser engine for barcode imaging scanner

A method comprising:

• illuminating an target object with diffusive light from a diffusive plate by projecting light from an illumination light source onto the diffusive plate that is substantially perpendicular to the optical axis of an imaging lens arrangement and covers a side face of a solid rectangular defining a volume space within which parts of a scan engine are deposited, said parts of the scan engine including at least the illumination light source, the imaging lens arrangement, an imaging sensor, and a controller for controlling both the illumination light source and the imaging sensor, wherein the diffusive plate comprises a first opening to allow light enter the imaging lens arrangement through the first opening, and wherein the area enclosed by the boundary of the diffusive plate substantially equal to the area of the side face having the dimension of a height H and a width W of the solid rectangular;
• detecting light from the target object through the imaging lens arrangement with photosensitive elements in the imaging sensor during a time period when the target object is illuminated by the diffusive light from all of a front surface of the diffusive plate;
• and
• mounting an auxiliary diffusive plate detachably on the scan engine with the auxiliary diffusive plate positioned outside the boundary of the diffusive plate, wherein the auxiliary diffusive plate is made of volume diffusion material and has two surfaces separated from each other by a distance that is less than one fifth (⅕) of both the height H and the width W of said volume space.

An apparatus comprising:

• an illumination light source for generating illumination light;
• an imaging lens arrangement;
• an imaging sensor having photosensitive elements;
• a controller for controlling both the illumination light source and the imaging sensor;
• wherein the controller, the imaging lens arrangement, and the imaging sensor are all deposited within the volume space of a solid rectangular having a height H, width W, and length L, and wherein the illumination light source includes one or more LEDs deposited outside the volume space of the solid rectangular;
• an auxiliary diffusive plate having an inner opening in the shape of a rectangular having the height thereof substantially identical to the height H of the volume space of the solid rectangular and having the width thereof substantially identical to the width W of the volume space of the solid rectangular, wherein the auxiliary diffusive plate is made of volume diffusion material and has two surfaces separated from each other by a distance that is less than one fifth (⅕) of both the height H and the width W of said volume space;
• and
• wherein the photosensitive elements in the imaging sensor are configured to detect light from a target object within an imaging field of view through the imaging lens arrangement during a time period when the target object is illuminated by diffusive light from the auxiliary diffusive plate as light from the illumination light source is projected onto the auxiliary diffusive plate.