Wide-viewing-angle switchable image splitter obtained using varied-line-spacing H-PDLC Bragg grating

ABSTRACT

We propose the use of a varied-line-spacing (VLS) holographic polymer-dispersed liquid crystal (H-PDLC) Bragg grating as a switchable image splitter to generate a compatible three-dimensional (3D) stereogram and to increase the viewing angle of the observer. To fabricate the VLS grating, a cylindrical lens is adopted to form a cylindrical wave, which interferes with a plane wave, generating an H-PDLC grating with a continuously varying period. The proposed holographic optical element (HOE)-based image splitter comprises two VLS H-PDLC gratings. It can be attached on a designed pattern, with two rectangles taking the place of conventional liquid crystal display panel pixels, and can separate them into right and left viewing fields with a wider range. Experimental results show that the movement of the eyes of the observer can reach 37.6 mm. A theoretical simulation indicates that a shorter focal length of the cylindrical lens can yield a larger movement range. Switching between two-dimensional and 3D modes can be performed by applying an external alternating-current voltage at ~80 V. The contrast ratio of the diffracted images induced by crosstalk is greater than 60%, which indicates the feasibility of the proposed HOE for 3D image splitting.

Graphical Abstract

KEYWORDS:

• Holographic optical elements
• liquid crystals
• polymers
• diffraction gratings

Acknowledgements

This work was supported by the Key Research Project from Shanghai Education Committee under Grant number 14ZZ138; the Shanghai Key Subject Construction Funding under Grant number s30502; and the National Key Scientific Instrument Development Projects under Grant number 2012YQ15008720.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Key Research Project from Shanghai Education Committee under Grant number 14ZZ138; the Shanghai Key Subject Construction Funding under Grant number s30502; and the National Key Scientific Instrument Development Projects under Grant number 2012YQ15008720.