The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 24, 1989
Filed:
Feb. 12, 1988
Ralph F Osterhout, San Francisco, CA (US);
Paul L Howard, Belmont, CA (US);
Greta G Light, San Mateo, CA (US);
Tekna, Inc., Redwood City, CA (US);
Abstract
A battery life indicator module that is mounted between a flashlight head assembly containing the light reflector and a battery casing assembly for holding the batteries is disclosed. The battery life indicator module contains an indicator, such as a light-emitting diode (LED). Internal to the battery life indicator module is a circuit which measures the battery level and activates the indicator to display the battery level. The module also provides the necessary electrical connection between the batteries and the light bulb of the flashlight. In the preferred embodiment, three LEDs are used to indicate various levels of charge. The monitoring circuit is activated by the ON/OFF switch of the flashlight so that power is not drained when the flashlight is not in use. The module has threads at its two ends for coupling to the flashlight head assembly and the battery casing assembly. The monitoring circuit contains a pair of voltage dividers for providing two voltages references. These references are provided to two comparators which also monitor the voltage level on the battery. The output of the comparators are provided to two of the LEDs, while the third LED is connected to the output of a NAND gate which has inputs from each of the comparators.