U.S. Precision Lens Delta II CRT Projection TV Focusing Lens 240-350mm f/2.8

U.S. Precision Lens Delta II CRT Projection TV Focusing Lens 240-350mm f/2.8

The U.S. Precision Lens Delta II is a glass optical focusing lens designed for CRT-based rear projection televisions. Manufactured by U.S. Precision Lens Incorporated of Cincinnati, Ohio, the Delta II mounts directly to a CRT projection tube to focus the image onto the projection screen. It features an adjustable focal range and a large-diameter glass element suited to the high-brightness CRT light path.

Specifications & What's Included

• Model: Delta II (Patent Pending)
• Manufacturer: U.S. Precision Lens Incorporated, Cincinnati, Ohio USA
• Lens Type: Glass optical lens
• Focal Length: 240mm to 350mm (approx.)
• Aperture: f/2.8
• Diameter: 5.25 inches
• Height: 8.25 inches
• Mounting: Four-tab bayonet-style mount for CRT tube fitment
• Adjustable focus via set screw on barrel
• Compatible with Sony CRT rear projection TV systems
• Lens only — no protective covers included

Applications

The Delta II focusing lens was designed for use in CRT-based rear projection televisions (RPTVs), primarily Sony and other large-screen projection TV systems that used three-tube CRT projection engines. In this type of system, three separate CRT tubes (red, green, and blue) each have a dedicated focusing lens mounted to their face; the Delta II is one such tube-mounted lens. The lens gathers and focuses the CRT's light output through the projection optics and onto the rear-projection screen. U.S. Precision Lens was a well-regarded Cincinnati-based specialty optics manufacturer whose projection lenses were used across a range of consumer and commercial CRT projection systems from the 1980s through the 1990s — the era when large-screen CRT rear projection was the dominant technology for big-picture home theater before LCD and DLP projectors took over. Today, Delta II lenses are sought by technicians and hobbyists restoring or maintaining vintage Sony and compatible RPTV systems, as well as by DIY projector builders who use surplus CRT tubes for large-format projection applications.