it seems to me that the list of files could be greater than Rick estimates, because there are 54 combinations per industry, and an unspecified number of industries. Still, if once written the number of overall PDF files remains reasonably static, this could still be dealt with in an array without the added complexity of a database. However, the larger the array, the more I would opt for a server-side solution.
Also PHP offers an alternative to having to amend the code every time a new PDF file is added, or an old one deleted (or even just a change to the title!). That is of storing the options in a CSV file, and dynamically creating the array. Then maintenance of the list of PDF files would be segregated from the maintenance of the code. You also have the option to maintain a list per industry, if appropriate. Assuming a list per industry, the CSV file could be something like:
camera,display,controller,product_code,filename,title,description
cam1,disp1,cont1,p111,p111.pdf,title,blah blah blah...
cam1,disp1,cont2,p112,p112.pdf,title,blah blah blah...
cam1,disp1,cont3,p112,p113.pdf,title,blah blah blah...
cam1,disp2,cont1,p121,p121.pdf,title,blah blah blah...
cam1,disp2,cont2,p122,p122.pdf,title,blah blah blah...
etc...
Note: One issue with CSV files is that spurious commas can blow the building of the array. That is why the text description (if included) is put at the end of the line. If it happens to contain commas, they merely truncate the description, and the remainder of the line is ignored.