Browse Prior Art Database

LIGHT SCATTERING DUAL DIFFUSER SYSTEM FOR LOW PROFILE PAGERS

IP.com Disclosure Number: IPCOM000006001D
Original Publication Date: 1990-Oct-01
Included in the Prior Art Database: 2001-Nov-23
Document File: 2 page(s) / 69K

Publishing Venue

Motorola

Related People

Tuan Nguyen: AUTHOR [+2]

Abstract

For low profile LCD pagers the problem is to develop a very low profiled diffuser that allows the end user to perceive an evenly lit LCD display. Commonly the diffusers are optic clear plastics with a light source entry point, usually a flat plane. This poses a problem in that, a) it does not optimize light entry, and b) the end user generally will end up with darker and lighter zones.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 57% of the total text.

Page 1 of 2

m

MOIYlROLA Technical Developments Volume 11 October 1990

LIGHT SCATTERING DUAL DIFFUSER SYSTEM FOR LOW PROFILE PAGERS

by Tuan Nguyen and Tom Rollins

   For low profile LCD pagers the problem is to develop a very low profiled diffuser that allows the end user to perceive an evenly lit LCD display. Commonly the diffusers are optic clear plastics with a light source entry point, usually a flat plane. This poses a problem in that, a) it does not optimize light entry, and b) the end user generally will end up with darker and lighter zones.

   Some pagers are tending towards the EL panel for perceived light diffusion. The problem encountered here is the cost of an added circuit with a tall component being the transformer. The EL panel reliability is also aconcern especially in a high temperature and humidity climate region. Therefore this design uses the LED's as a light source and a dual light scattering diffuser to create the effect of an EL panel even light diffusion.

   An N th number of LED's are located such that the die direction is pointed towards the diffuser and is each partially placed into the concave features of the diffuser. The concave feature is the first light scattering system used to diverge incident light, resulting into a negative focal length that cannot form a visible light pattern. For additional light scattering effect the wncave surface has a multiplicity of diamond cut shapes. As the light enters the body of the diffuser an angled base (approx 6") is...