Browse Prior Art Database

BACKLIGHT LAMP LOCATED BY REFLECTIVE CONTACT

IP.com Disclosure Number: IPCOM000006342D
Original Publication Date: 1991-Dec-01
Included in the Prior Art Database: 2001-Dec-26
Document File: 1 page(s) / 57K

Publishing Venue

Motorola

Related People

Cliff Anderson: AUTHOR [+2]

Abstract

With the trend toward more compact electronic communication devices, backlighting for LCD displays is often compromised because of the restriction that the lamp be soldered directly to the circuit board. In the typical application, a light pipe or dBuser is assem- bled to capture the light, transport it to the area behind the LCD, and redirect it off of a diise surface or via a diffuse medium through the LCD. The geometry of the light pipe becomes complicated and its performance is compromised in terms of light distribution and throughput due to geometric restrictions associated with the placement of the lamp. In addition, the incan- descent lamps typically used radiate light in a 360" arc that would requiwa reflector to capture most of the light. This would represent an extra part.

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MOTOROLA INC. Technical Developments Volume 14 December 1991

BACKLIGHT LAMP LOCATED BY REFLECTIVE CONTACT

by Cliff Anderson and Gus Suarez

   With the trend toward more compact electronic communication devices, backlighting for LCD displays is often compromised because of the restriction that the lamp be soldered directly to the circuit board. In the typical application, a light pipe or dBuser is assem- bled to capture the light, transport it to the area behind the LCD, and redirect it off of a diise surface or via a diffuse medium through the LCD. The geometry of the light pipe becomes complicated and its performance is compromised in terms of light distribution and throughput due to geometric restrictions associated with the placement of the lamp. In addition, the incan- descent lamps typically used radiate light in a 360" arc that would requiwa reflector to capture most of the light. This would represent an extra part.

  The invention described herein is comprised of a conductive metal contact that locates the lamp for opti- mal light distribution and throughput and has a reflec- tive surface behind the lamp to increase light output. An implementation is shown in Figure 1. The positive and negative leads (2) for the lamp (1) are soldered onto the circuit board (3) and the lamp is snapped and/or soldered into the contact. The contact is designed to position the lamp for optimal light output relative to the LCD (4) and diffuser (5), and to reflect light transmitted f...