Wide angle mini-LEDs combined with multifocal micro reflector cavity for thin portable device flashlight

Abstract

LEDs employed in portable device flashes are Lambertian light sources, additional optical components such as Fresnel lenses and reflector cups must be incorporated to adjust the light distribution. This results in a need for a certain module thickness or high alignment precision. This paper introduces a modification in the packaging structure of mini-LEDs by employing a first optical design to create wide-angle mini-LEDs (WA mini-LEDs) with a light emission angle of 180°. A multi-focal micro-reflector cavity (MF-MRC) is included in the packaging process, thus enabling the achievement of a slim flash module. For the prototype design, measurements were conducted using WA mini-LEDs combined with a 2 mm height MF-MRC. The full width at half maximum can be reduced to 56° while maintaining a uniformity of up to 60% across all measurement points. Additionally, the center illuminance is 3.24 times higher compared to Lambertian mini-LED light sources.

Keywords:

• Wide angle mini-LEDs
• flashlight
• first optical design
• multi-focal
• micro-reflector cavity
• full width at half maximum
• portable device

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Authors contributions

Zhi Ting Ye and Chia Chun Hu are responsible for the structure and conception of the entire article. Zhi Ting Ye and Chia Chun Hu is responsible for the simulation data of the article. Zhi Ting Ye and Chang Che Chiu is responsible for the initial writing of the manuscript.

Disclosure statement

The authors declare that they have no competing interests.

Data availability statement

The data presented in this study are available on request from the all authors.

Additional information

Funding

This work was supported by the National Science and Technology Council of Taiwan (NTSC 112-2622-E-194-004).