I have an Infocus projector model LP1000B  There is a side panel which
when I opened can see two slots (top & bottom) which seem to be for
holding sone kind of slide-in screen or filter.  From the
configuration of the hardware inside this cavity, I do not think this
to be for an air filter.

Finding parts diagrams and/or technical manuals for this model is next
to impossible for a mere mortal such as myself.

The Infocus web stie is of little help in even finding a service
center.  Does anyone know how/where I might obtain a parts diagram
and/or a technical maunal for this model?

Any reply is greatly appreciated.  Thank you.

Everything that you require should be found at the Infocus LP1000 projector site:

http://www.infocus.com/service/lp1000/index.asp

The maintenance and troubleshooting PDF explains how to remove and
clean the filter, which is recommended after every 100 hours of use.

(If this is what you were looking for, please save your money and
e-mail the address at the bottom of this page, telling Google that
they would have collected an answer fee if they had made tcovert-ga a
Google Researcher.)