1 EXHIBIT 99.1 June 18, 1998 Mr. Douglas P. Baker Vice President and Chief Financial Officer SI Diamond Technology, Inc. 12100 Technology Blvd. Austin, TX 78727 Dear Mr. Baker: This is to confirm that the client-auditor relationship between SI Diamond Technology, Inc. (Commission File Number 1-11602) and Coopers & Lybrand L.L.P. has ceased. Very truly yours, /s/ COOPERS & LYBRAND L.L.P. Coopers & Lybrand L.L.P. cc: Office of the Chief Accountant SECPS Letter File Securities and Exchange Commission Mail Stop 11-3 450 Fifth Street, N.W. Washington, D.C. 20549