Holographix was awarded several patents in the area of grating-based scanners:
4,488,042 — Line scan reader/writer by holographic collection (Re 32735)
4,923,262 — Scanner system having rotating deflector hologram
5,182,659 — Holographic recording and scanning system and method
5,270,842 — Holographic recording and scanning system and method
6,288,817 — High duty cycle synchronized multi-line scanner
Holographic-based scanning systems have been used for years in the high resolution prepress markets where monochromatic lasers are generally utilized. However, until recently, due to the dispersive properties of holographic optical elements (HOEs), along with the high cost associated with recording “master” HOEs, holographic scanners have not been able to penetrate major scanning markets such as the laser printer and digital copier markets, low to mid-range imagesetter markets, and the non-contact inspection scanner market. Each of these markets has developed cost effective laser diode based solutions using conventional scanning approaches such as polygon/f-theta lens combinations. In order to penetrate these markets, holographic-based systems must exhibit low cost and immunity to wavelength shifts associated with laser diodes. This paper describes recent developments in the design of holographic scanners in which multiple HOEs, each possessing optical power, are used in conjunction with one curved mirror to passively correct focal plane position errors and spot size changes caused by the wavelength instability of laser diodes. This paper also describes recent advancements in low cost production of high quality HOEs and curved mirrors. Together these developments allow holographic scanners to be economically competitive alternatives to conventional devices in every segment of the laser scanning industry.
There are several methods currently available for replicating high-quality patterned optical surfaces. This paper investigates the optical performance of replicated imaging quality diffraction gratings, interferometric encoders, and performance enhancing surface relief structures manufactured with ultraviolet curable photopolymers (UVPP) as an integral part of the replication process. Through the development of a UVPP replication process, fabrication times of the desired optical components are decreased while product quality is maintained, and in many cases increased. Attractive low cost replication based solutions to several optical manufacturing problems are discussed.
Replication techniques based on light-cured photopolymers make possible the mass-production of microstructured optics with feature sizes of much less than a micron.