GB2530006A

GB2530006A - Low power lighting

Info

Publication number: GB2530006A
Application number: GB1412262.6A
Authority: GB
Inventors: Robert Stewart
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-07-10
Filing date: 2014-07-10
Publication date: 2016-03-16
Also published as: GB201412262D0

Abstract

Four LEDs, or groups of LEDs 3,4,5,6, are mounted facing outwards 7, or towards the area to be illuminated 8, at 90 degree angles to each other on a printed circuit board 1.The lights are flickered on and off sequentially to spin a beam of light through a wide area at a frequency fast enough so that due to visual persistence the lights appear to be constantly on. A frequency of 40hz would be sufficient for this purpose. The printed circuit board may have a hole 2 in the centre to allow it to be mounted on a pole or walking stick. A diffuser 9 may be used for visual safety. The device may be powered by a solar panel and may have a USB port for charging other devices.

Description

Low power lighting This invention relates to the problem of illuminating a wide area, in darkness, where portability and illumination power demands, reduce the effective beam width to maintain satisfactory visibility. It also relates to use on bicycles, walking poles, and applications which collect solar power in the day for night-time illumination.

To overcome this, the present invention spins a beam of light through a wider area, at speeds above the human visual flicker frequency (40Hz) utilising 1/4 to 1/3w of the power that would normally be required to do so, using visual persistence; the human eye's ability to remember what has been seen, to create the illusion that the whole area is illuminated at once.

By lowering power consumption, portable battery lifetime is extended, compared to an equivalent fixed beam design, and the swept area extends visibility dramatically.

Examples of the invention will now be described by referring to the accompanying drawings * Figure 1 shows the the practical layout of the device, and the swept area.

* Figure 2 shows the circuit design, and led driving timing diagram.

* Figure 3 shows the cubic housing proposed and how it would be used * Figure 4 shows the housing design for a walking stick or pole Referring to figure 1.

A circular, or rectangular printed circuit (1) above the area being illuminated, with control electronics on board, has 4 individual, or groups, of wide beam (90-120 degree) dome lens leds (3,4,5,6) mounted on, or above the 4 cardinal points of the compass, 0, 90, 180, 270 degrees, projecting outwards (7), or towards the area being illuminated (8). The printed circuit board may have a hole (2) in the centre to allow it to be mounted on a walking pole, or stick. Due to the point source brightness of the leds a diffuser (9) may be needed for visual safety, especially with children.

Referring to Figure 2 The control electronics consist ofabattery, or series group of batteries (i), powering a microcontroller (2) via a voltage regulator (4). The microcontroller obtains a clock signal from connected quartz crystal (3), and drives the 4 individual, or groups of leds (5) using a driver circuit (6). The following can also be connected; a temperature sensor (7) , light sensor (8) (either linear or digital in output), EEprom memory circuit (9), tilt switch (10), and vibration sensor(i 1), powered by the voltage regulator. For indication purposes an LED (17) can also be used and connected to the microcontroller.

The four leds are driven sequentially according to the waveforms shown in the timing diagram such that there is a projected visual overlap between the sequentially illuminated areas. The on pulses (12,13,14,15) are of variable length, or fixed duration, however the total contiguous duration (16) of each swept rotation, stays the same at <25ms or > 40Hz. For use in cycling the swept speed must increase to accommodate visual stroboscopic effects possible in passing objects close to the light.

Referring to Figure 3 Two half cubic clear plastic housings (1,2) are designed to mate together to form a cubic enclosure (9), held together by a set of 4 screws and PCB pillars. The pillars inside support a rectangular PCB described in figure 2 such that the LEDs on this point downward or upwards depending on which way round the cube is oriented from hanging eyelets (3,4), The mated cubic assembly is designed to also mate with a solar panel holder (5) which allows the unit to be charged from the sun via a solar panel held in the tray (6). The solar panel is held in place by magnets (7), allowing power to flow from the solar panel through the cubic housing via through connectors (8) inserted into the housing. Four connectors are proposed to allow for power and data transfer to and from the cubic assembly. The solar panel assembly (10) has an infra red light reflective coating which reflects the heat that builds up in the panel away from the cubic enclosure below. This prevents the batteries inside the cubic enclosure, from overheating while charging in full sun. It also may contain a charging circuit to provide power via a IJSB connector for mobile phone charging using the device batteries as a charging source. The solar panel can also be remotely located and connected by cable to the device.

The cubic assembly (9) is made watertight using membrane seals, and has no through switches or pushbuttons. Referring to Figure 2, instructions and data are conveyed by either closure of the tilt switch (10) or movement of the vibration sensor (11) Referring to Figure 4 A cylindrical housing is positioned either at the centre of balance (1), or at the handle end (2) of a walking pole. The housing (I) has a tubular centre and can be moved along the length of the walking pole (3), to suit user height, or it can be incorporated into the handle (2). Inside the housing resides the PCB, batteries, and associated circuits (see figure 2). The batteries which power the device can alternately reside inside the shaft of the walking stick itself, if hollow. The housing is keyed (4) to prevent rotation on the shaft.

Claims

Claims 1. A swept light beam device which digitally rotates a beam of light at speeds above 40Hz, at adjustable duty cycle.
2. A device which can be handheld, or suspended, or attached to a bicycle, or walking pole.

3, A device which can be charged via solar photovoltaic, or other source, and can independently charge a mobile phone, or other battery operated device.