Multifield direct design method for ultrashort throw ratio projection optics with two tailored mirrors.

Area of Science:

• Optics and Photonics
• Optical Engineering
• Display Technology

Background:

• Traditional projection systems require significant distances, limiting their application in space-constrained environments.
• Developing compact projection optics with high imaging quality remains a challenge.

Purpose of the Study:

• To present a multifield direct design method for ultrashort throw ratio projection optics.
• To enable the design of compact projection systems using freeform mirrors.

Main Methods:

• A multifield direct design method was employed to calculate two freeform mirror profiles.
• Odd polynomials were used to fit the mirror profiles, serving as an initial design in optical software.
• The mirrors were further optimized as XY polynomial freeform surfaces.

Main Results:

• The final system, incorporating two freeform mirrors and a standard lens, reduced projection distance from 2 m to 48 cm for a 78.3-inch screen.
• Modulation transfer function improved to over 0.6 at 0.5 lp/mm, compared to 0.43 for a rotationally symmetric design.
• Image distortion was reduced to less than 1.5% across the entire field of view.

Conclusions:

• The multifield direct design method effectively produces ultrashort throw ratio projection optics.
• The use of freeform mirrors significantly enhances imaging performance and reduces system size.
• This approach offers a well-tailored solution for high-quality, compact projection displays.