1. Field of the Invention
The Present invention relates to battery powered LED lamps.
2. Discussion of Related Art
There are currently many forms of small, inexpensive lamps that employ LEDs. Many of these products may be used around cabinets in the home. They usually serve to illuminate one particular spot in a cabinet, perhaps on a shelve, or under a cabinet. Another thing that most of these lamps have in common is a mechanical switch used to activate and de-activate the lamp. Some switches are placed to interface with a door. Others are manually operated. A few of these products use a photo sensor to recognize darkness and activate the lamp when the ambient light level is low.
The other common construction feature of currently available lamps is that the LEDs are always mounted perpendicular to the mounting surface of the lamp. This limits the direction that the LED light can be broadcast to a straight-ahead direction.
The Door-mounted Cabinet Lamp has one or more LEDs placed in the same plane as the plane of the mounting surface. In a favorite embodiment, the lamp is disc shaped with a series of LEDs around the perimeter of the disc. When the lamp is attached to the inside surface of a cabinet door and the cabinet door is in the open position, the LEDs will broadcast light into the cabinet in a very helpful manner. The use of multiple LEDs, placed around the perimeter of the disc shaped lamp, provides light into the contents of several shelves at the same time.
In lieu of a mechanical switch, a photo sensor is used to detect a rapid change from dark to tight as the cabinet door is opened. The signal from the photo sensor is analyzed by a microprocessor so that a prescribed increase in ambient light within a prescribed time is sufficient to activate the LEDs. A timer within the program of the microprocessor controls the de-activation of the LEDs. In order to be activated again, the photo sensor must first see a decrease in ambient light, as would happen when the cabinet door is closed again.
Referring to
Starting with the Power Source, it can be any source of DC power suitable for operating the Microprocessor, Photo Sensor, and LEDs. In the simplest case, batteries are used.
The Photo Sensor sends a signal to the Microprocessor that represents the light level at the Photo Sensor. When the cabinet door is closed, the Photo Sensor sends a signal that represents relative darkness. When the door is opened, the signal represents a increased light level.
The Microprocessor does not react to prescribed light levels, but rather it reacts to a sudden increase in light level, which happens when the door is opened and the Photo Sensor is exposed to the ambient light in the room. U.S. Pat. No. 5,892,331, Hollaway, describes this unique method of operation and its application in a closet. The Hollaway patent also describes a timer function which de-activates the light bulb after a prescribed period of time. The Door-mounted Cabinet Lamp operates the same way as the Hollaway invention.
The Microprocessor is programmed to control power to one or more LEDs in response to signals from the Photo Sensor, so that each time the door is opened the LEDs are activated. The Microprocessor is also programmed to de-active the LEDs after a short period of time, perhaps in 15 seconds.
Referring now to
Photo Sensor 11 is connected to Circuit Board 3 and positioned within an opening that senses ambient light outside Enclosure 1. When the cabinet door is closed Photo Sensor 11 will be in a relatively dark environment, but when the door is opened Photo Sensor 11 will view the ambient light outside the cabinet and activate LEDs 4, 5, 6, and 7.
Although a preferred embodiment has been described, there are many variations of the present invention that may be used. The Power Source, for example, may be 120 VAC household power. The Photo Sensor may be mounted in the Lamp in various locations, as long as an increase in light occurs at the Photo Sensor whenever the Door is opened. The LEDs can be arranged in many ways, or even replaced with other types of light producing elements, as long as light is broadcast into the cabinet when the door is in the open position.