Lighting device

There is provided a lighting device for illuminating objects inside an enclosure including a housing, an array of light emitting diodes enclosed by the housing consisting of at least two groups of diodes, one group emitting substantially white light and one group emitting colored light, a DC to DC converter feeding the light-emitting diodes and enclosed by the housing, and a light intensity controller for operating each of the groups of diodes at variable light intensities.

FIELD OF THE INVENTION

The present invention relates to a lighting device and more particularly, to a lighting device suitable for military use, especially in vehicles.

BACKGROUND OF THE INVENTION

There often exists a need, both for military and civilian purposes, to utilize a lighting device which can provide regular bright illumination as commonly required, as well as to selectively provide lighting of a different nature, e.g., white and colored lights of limited illumination or of controllable light intensity.

DISCLOSURE OF THE INVENTION

According to the present invention, there is therefore provided a lighting device for illuminating objects inside an enclosure comprising a housing, an array of light emitting diodes enclosed by said housing consisting of at least two groups of diodes, at least one group emitting substantially white light and at least one group emitting colored light, a DC to DC converter feeding said light-emitting diodes and enclosed by said housing, and at least one light intensity control means for operating each of said groups of diodes at variable light intensities.

DETAILED DESCRIPTION

A first embodiment of a lighting device2according to the present invention is illustrated inFIGS. 1 and 2. Seen is a housing4advantageously a two-part housing composed of an enclosure6and a base plate8of a curved configuration, hermetically sealed to render it waterproof. The housing parts6and8are interconnectable in any per-se known manner such as by press fitting and/or by screws. The enclosure6has an opening10, protected by a transparent cover, preferably made of polycarbonate, accommodating an array of LEDs12, details of which will be described hereinafter. Further seen is a selector embodied by a toggle switch16and a member18for adjusting a light intensity controller, e.g., a potentiometer or a logic circuit, for dimming or brightening the LEDs12. Also provided is an inlet electrical port20. The base plate8is preferably made with flanges22, facilitating anchoring of the housing4to a wall or ceiling.

The PCB-mounted array of LEDs12, advantageously consists of 32 white LEDs24interlaced with 16 blue (wavelength ˜470 nm), green or red LEDs26providing an active LED area of approximately 30×68 mm. The 32 white LEDs24are energized from a 160 mA, 14 Vdc source, while the 16 blue LEDs26are energized from 100 mA, 14 Vdc source. The desired luminous intensity of each white LED is typically ˜400 mcd at 120 degrees.

The white LEDs provide light for general activity, e.g., map reading, orientation etc. during daytime and nocturnal non-combat activities, whereas the blue LEDs provide light for nocturnal combat activity. The advantage of blue light during combat activity is that blue light is less detectable by night vision equipment of the enemy in the event that some of it leaks out through openings in the vehicle, e.g., periscope. Alternatively, red (wavelength ˜630 nm) LEDs may be used instead of the blue ones during nocturnal activity. The advantage of red light is that (although detectable by night vision equipment) it does not impair the high sensitivity of the dark-adapted human eye.

Referring toFIGS. 3 and 4, there is illustrated a further embodiment of the lighting device2according to the present invention. Seen is the enclosure6, the base plate8to which the enclosure6is attachable, the opening10, protected by a transparent cover, the array of white and colored LEDs12, an emergency button28, as well as other parts of the device numbered by the same numbers allocated to the various parts shown inFIGS. 1 and 2. Inside the enclosure6(FIG. 4) there are further located a powerpack30held in position by a support plate32, a PCB34and a heat sink36for dispersing the heat generated by the LEDs12.

The device2is externally powered from a DC source, e.g., 18-36 Vdc of a vehicle's battery38(FIG. 5), through input plugs and/or sockets20and optionally includes an internal rechargeable powerpack30, which is held in position by a support plate32. The powerpack30may be formed by two sub-units, one operable for short periods of time using a super-capacitor, while the other sub-unit for a longer period of time, utilizing rechargeable batteries. The internal powerpack30enables the lighting device to provide light even in a damaged vehicle thus, for example, assisting the crew to escape and/or be rescued from the damaged vehicle. Furthermore, the internal powerpack30facilitates utilization of the device as an independent portable flashlight.

Turning now toFIG. 5, there is illustrated a block diagram of the lighting device according to the present invention, illustrating the structure and operation of the lighting device. Under normal conditions the vehicle's battery38feeds the driver and power electronics40,42, the LEDs12via a DC to DC converter44and the powerpack charger46. When the vehicle's battery is disconnected due to some reason, the internal powerpack30, which may be of a lower voltage than the vehicle's voltage, e.g., 3.6 Vdc, is automatically enabled for a predetermined short period of emergency operation, e.g., 30 seconds. An additional period (e.g., 15 minutes) of emergency operation is selectable by briefly pressing the emergency pushbutton28. This can be repeated several times with total emergency capacity of at least 60 minutes. The isolation switch48prevents unnecessary discharge of the powerpack30. The controller50controls the entire electronic circuit (the circuit may also include a low noise built-in EMI RFI filter) during normal and emergency operations according to the program fused into its memory, as well as the data that flows into its inputs from the circuit components, the vehicle's battery and the environment. Furthermore, the controller50also monitors the voltage of the vehicle's battery38and renders the LEDs12blinking when this voltage falls under a predetermined value. This feature is particularly important during a silent ambush, when the vehicle's engine is not working and the vehicle's restart is dependable on the vehicle's batteries being sufficiently charged.

The light intensity control52serves for controlling the variable light intensity of at least one group of the two groups of light emitting diodes, for the purpose of dimming or brightening same. It may be activated manually by the manipulatable member18or by any per-se known manner such as a selector, a keypad, a proximity sensor, etc. It can also be activated by a software program either directly or via a communication line.