Browse Prior Art Database

AUTOMATIC BACKLIGHTING DEVICE

IP.com Disclosure Number: IPCOM000006626D
Original Publication Date: 1992-Aug-01
Included in the Prior Art Database: 2002-Jan-17
Document File: 1 page(s) / 48K

Publishing Venue

Motorola

Related People

Mike Goldenberg: AUTHOR [+2]

Abstract

When an electronic product incorporates a display which might be used in low light conditions, it becomes desirable to provide a backlighting means to illuminate the display. One drawback with backlighting is that an extra button is often needed to turn on the device. An approach to eliminating the lamp button includes hury- ing the switching process in a software algorithm, which is c&en confusing and unappealing to the consumer. What is needed is backlighting which is automatically activated by product use.

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 99% of the total text.

Page 1 of 1

MOTOROLA INC. Technical Developments Volume 16 August 1992

AUTOMATIC BACKLIGHTING DEVICE

by Mike Goldenberg and Evencio Fernandez

  When an electronic product incorporates a display which might be used in low light conditions, it becomes desirable to provide a backlighting means to illuminate the display. One drawback with backlighting is that an extra button is often needed to turn on the device. An approach to eliminating the lamp button includes hury- ing the switching process in a software algorithm, which is c&en confusing and unappealing to the consumer. What is needed is backlighting which is automatically activated by product use.

  An illumination circuit could be constructed which utilized a light sensing device to determine if backlighting were necessary to the user. The circuit would require the simultaneous occurrence of two factors to turn on the lighting device. Upon the actuation of any button (meaning that the display is about to be read), the circuit turns on the phototransistor, and ifthe device generates a signal indicating that the ambient light level is too low to read the display message, the light is turned on. The light stays on for a predetermined length of time (about 10 seconds) following the last button actuation. After the time period expires without a button actuation, the light turns off.

PHOTOTRANSISTOR ON

PHOTOTRANSISTOR

OFF

PHOTOTRANSISTOR

OFF

BACKL.IGHT OFF

1

BACKLIGHT ON

YES

NO

ACTUATION ?

167

[This page contains 14 pictures or ot...