A novel optical film to provide a highly collimated planar light source

Abstract

In this paper, we proposed a novel optical film 'Collimation Film with Equivalent Focal Reflective Aperture' (CFEFRA) that can collocate with the proper light guide plate (LGP) to provide a highly collimated planar light source (HCPLS) that not only has high intensity peak but also good uniformity. The CFEFRA has micro-cylindrical lenses and inverted-prism-like micro-teeth on its upper surface and lower surface, respectively. The lower micro-teeth that are aligned with the upper lenses can deflect the light emitting from the LGP at large declination into the normal, and then the deflected light with transverse fan-out is further converged by the upper lens to become the collimated light. The exact alignment between the upper and lower micro-structures is fulfilled by the method 'auto-secure-alignment by focusing of a collimated exposure beam'. The vertical and horizontal full width at half maximum (FWHM) of angular intensity of the HCPLS for the optimal case are of 14 and 6 degrees, respectively. Moreover, it still has high optical efficiency with light output of over 90% despite the resultant emitting light is such collimated. Most importantly, CFEFRA just needs to collocate with a relatively low-cost and easily-manufactured LGP so the HCPLS adopting the CFEFRA can be extended for large-sized application. Both optical model and experimental samples are demonstrated in this paper, and the simulation results are consistent with the experimental results. The consistency proves our design concept and optical model are convincible and feasible.

Wide field of view flat-panel head-up display system

“…A possible realization of this backlight consists of an LED array matched with a custom microlens array and some engineered diffusers to improve spatial uniformity 7 , 8 . Other backlight possibilities, such as edge lit light guide plate with prism arrays, 9 scattering micro-dots and a cone prism sheet, 10 or other advanced micro optical arrays 11 , 12 have been described in the literature. The proposed LED array-based collimated backlight is capable of reaching high virtual image brightness up to 10000 cd/m2 require for a HUD in a sun-lit environment, 13 , 14 as well as it provides localized dimming enhancing the contrast ratio and saving energy.…”

A High Performance Single-Domain LCD With Wide Luminance Distribution

“…There are also multi-layer micro-structured backlight plates as described in [39], in which the main layer serves to guide the light through, and a reflective layer with micro-structures on the bottom serves to collimate the backlight. Another multi-layer QCBL employs micro-lenses to obtain a fairly collimated backlight distribution [33], [40].…”

Microstructure density generation for backlight display using probability analysis method

“…Being responsible for providing light to LCD, a conven tional backlight model (BLM) consists of light sources, a light guide plate (LGP), reflective films and brightness enhance ment films (BEFs). In order to further improve the uniformity and the light utilization efficiency, as well as reduce the thick ness of the BLM, researchers have been paying much atten tion to the optimal algorithm and optical structure design on the LGP or on the optical film [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Some researchers proposed a hybrid LGP design with microstructures on the top and bottom surfaces.…”