DK178279B1

DK178279B1 - Emergency marine light including visible and infra red light sources

Info

Publication number: DK178279B1
Application number: DK201470393A
Authority: DK
Inventors: Lars Nørgaard Bjørn
Original assignee: Daniamant Aps
Priority date: 2014-06-27
Filing date: 2014-06-27
Publication date: 2015-11-02

Abstract

The present invention relates to an emergency marine light for a life jacket or a raft, said emergency marine light comprising a first light source for emitting light in a first frequency range in a first time period, a second light source for emitting light in a second frequency range in a second time period, and control means for controlling light emission from the first and the second light sources in accordance with a predetermined light emission scheme. The present invention further relates to an associated method.

Description

EMERGENCY MARINE LIGHT INCLUDING VISIBLE AND INFRA RED LIGHT SOURCES FIELD OF THE INVENION

The present invention relates to an emergency marine light having at least two different types of light sources. In particular, the present invention relates to an emergency marine light having one light source being dedicated for use i daylight and another light source being dedication for use during night time.

BACKGROUND OF THE INVENTION

Various emergency marine light devices have been suggested over the years. The development of these have been driven by a variety of parameters, such as international regulations. According to these international regulations emergency lights (visible light) should be flashed between 50 and 70 times per minute for a period of at least 8 hours.

As an example of prior art systems US 2012/265788 A1 teaches a visibility system that includes a portable navigation lighting system including a housing and a light source. When being switched on the light source is visible from outside the housing in such a manner that at least a first and a second colour are displayed.

It is a drawback of conventional emergency marine lights that it may be difficult to see and spot them during night hours, in particular over rough seas.

In view of the above it may be seen as an object of embodiments of the present invention to provide an emergency marine light having an enhanced visibility.

It may be seen as a further object of embodiments of the present invention to provide an emergency marine light having an enhanced visibility during night time.

DESCRIPTION OF THE INVENTION

The above-mentioned objects are complied with by providing, in a first aspect, an emergency marine light for a life jacket or a raft, said emergency marine light comprising - a first light source for emitting light in a first frequency range in a first time period, - a second light source for emitting light in a second frequency range in a second time period, and - control means for controlling light emission from the first and the second light sources in accordance with a predetermined light emission scheme.

The aim and associated advantage of the emergency marine light of the present invention is to enhance visibility and thereby the chances of getting spotted and saved on the open sea. The emergency marine light according to the present invention may in principle be used in connection with any kind of life saving equipment, such as life jackets, rafts etc.

The enhanced visibility offered by the present invention is of particular importance during night hours and in connection with poor visibility. With this in mind the emergency marine light of the present invention provides a light source having optimal performance during day hours, and another light source having optimal performance during night hours or in connection with other low-visibility conditions, such as rain, fog, haze etc.

The first and second light sources may be separate light sources or they may be combined into a single light source is possible.

The predetermined light emission scheme may involve light emission as a function external parameters, such as time, battery capacity, detected light intensity or even a combination thereof.

The first light source may comprise a first LED adapted to emit visible light, i.e. in the 400-700 nm range. The second light source may comprise a second LED adapted to emit infrared light, i.e. typically in the 700-2000 nm range. Laser diodes may also be applicable light sources. It is advantageous that the infrared light source is visible through infrared night vision systems in for example helicopters, warships, coastguards etc.

The control means may be configured to control that the second time period follows the first time period so that only one of the light sources is emitting light at a given time. Thus, the second time period may immediately follow the first time period. Alternatively, both light sources may be switched off between the first and second time periods.

The emergency marine light may further comprise a light detector for detecting the intensity of the surrounding light. In this way the actual visibility may be determined. It may also be determined whether it is day of night. The detected light intensity may be provided as a control signal to the control means.

In a second aspect, the present invention relates to a method for operating an emergency marine light for a life jacket or a raft, said method comprising the steps of - activating a first light source adapted to emit light in a first frequency range in a first time period, and - activating a second light source adapted to emit light in a second frequency range in a second time period, wherein the second time period follows the first time period so that only one of the light sources is activated at a given time.

Again, the first light source may comprise a first LED adapted to emit visible light, i.e. in the 400-700 nm range. The second light source may comprise a second LED adapted to emit infrared light, i.e. typically in the 700-2000 nm range. Laser diodes may also be applicable light sources. It is advantageous that the infrared light source is visible through infrared night vision system in for example helicopters, warships, coastguards etc.

The duration of the first time period may be shorter than 0.5 s, such as shorter than 0.4 s, such as approximately 0.3 s. The duration of the second time period may be shorter than 0.7 s, such as shorter than 0.6 s, such as shorter than 0.5 s, such as shorter than 0.4 s. As mentioned above the second time period may immediately follow the first time period. Alternatively, both light sources may be switched off between the first and second time periods.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described in further details with reference to the accompanying figures, where

Fig. 1 shows a block diagram of the electronics of the emergency light source, and

Fig. 2 shows a typical light emission pattern of the two light sources.

While the invention is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of examples in the drawings and will be described in detail herein. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE INVENTION

In its most general aspect the present invention relates to an emergency marine light with enhanced visibility and thereby increased chances of getting spotted and saved in particular during night hours. The emergency marine light according to the present invention finds its primary use in connection with marine life saving equipment, such as life jackets and rafts.

Fig. 1 shows a schematic block diagram of an embodiment of the present invention. As seen Fig. 1 the emergency marine light 100 comprises a battery 101, a microprocessor 102 and two light sources 103, 104 here shown as light emitting diodes (LEDs). However, for example semiconductor laser diodes may be applicable as well. Also, the emergency marine light may involve two different types of light sources, such as an LED and a laser diode.

The microprocessor 102 generates respective turn on/off signals to the two light sources via switches 105, 106. Moreover, the microprocessor 102 generates pulse width modulated (PWM) drive signals PWM2 and PWM4 signals to switches 107, 108, respectively. The PWM drive signals are provided to switches 107, 108 during the respective on-time of the switches 105, 106. The PWM2 signal is at least partly generated on the basis of the current feedback 109. Similarly, the PWM4 signal is at least partly generated on the basis of the current feedback 110.

The controllable switch 107 form a first voltage booster in combination with inductance 111 and diode 113. Similarly, the controllable switch 108 form a second voltage booster in combination with inductance 112 and diode 114. The two voltage boosters ensure that the battery voltage level is matched to voltage levels of LEDs 103, 104.

Preferably, one of the LEDs, say 103, is adapted to emit visible light, i.e. in the 400-700 nm range, whereas the other LED, say 104, is adapted to emit infrared light, i.e. typically in the 700-2000 nm range, such as around 1.3 pm and 1.5 pm. The aim of incorporating an infrared light source is to make the emergency marine light highly visible on for example infrared detection systems of the coastguard.

The battery 101 may in principle be any kind of battery, such as a lithium battery or a standard alkaline battery. The physical size of the battery chosen may comply with the AA, AAA or AAAA standards.

The block diagram depicted in Fig. 1 is encapsulated in some sort of waterproof shell having two transparent regions or zones for light emission. Moreover, a push button for manual activation and/or a sensor for automatic water activation may advantageously be provided.

Fig. 2 shows a possible light emitting sequence where visible light is emitting in 0.3 s (solid line) and infrared light is emitting in the time period between tx and t2 (dashed line). In principle the infrared LED may be emitting at any time between t=0.3 s and t=l s, i.e. in a time period ranging from 0.7 s to only a short flash. Another emitting sequence may involve that the visible light flashes constantly, i.e. day and night, whereas the infrared light source is only active during night hours.

As to the possible light emitting sequence suggested in connection with Fig. 2 the emission sequence of the visible light source is regulated by international regulations whereas the emission sequence of the infrared light source can be set more or less arbitrary. Thus, the visible light source may be set to emit light during daytime in accordance with international regulations, whereas the infrared light source may be set to emit light during night time in accordance with a preselected scheme.

Claims

1. Maritime emergency light for a life jacket or fleet, comprising maritime emergency light - a first light source for emission of light within a first frequency range in a first period, - a second light source for emission of light in a second frequency interval for a second period, and - a control means for controlling light emission from the first and second light sources according to a predetermined light emission plan.

A marine emergency light according to claim 1, wherein the predetermined light emission plan involves light emission as a function of time, battery capacity, detected light intensity or a combination thereof.

Maritime emergency light according to claim 1 or 2, wherein the first light source comprises a first LED adapted to emit visible light.

A marine emergency light according to any one of claims 1-3, wherein the second light source comprises a second LED adapted to emit infrared light.

Maritime emergency light according to any one of claims 1-4, wherein the control means is configured to control that the second period follows the first period, so that only one of the light sources emits light at a given time.

A marine emergency light according to any one of claims 1-5, further comprising a light detector for detecting the intensity of the ambient light.

The marine emergency light of claim 6, wherein the detected light intensity is provided as a control signal to the control means.

A method of operating a marine emergency light for a life jacket or fleet, comprising the steps of - activating a first light source adapted to emit light within a first frequency range for a first period of time, and - activating a a second light source adapted to emit light at a different frequency range for a second period, the second period following the first period, so that only one of the light sources is activated at a given time.

The method of claim 8, wherein the first light source comprises a first LED adapted to emit visible light.

The method of claim 8 or 9, wherein the second light source comprises a second LED adapted to emit infrared light.

A method according to any of claims 8-10, wherein the duration of the first period is shorter than 0.5 s, such as shorter than 0.4 s, such as approx. 0.3 s.

The method of any of claims 8-11, wherein the duration of the second period is shorter than 0.7 s, such as shorter than 0.6 s, such as shorter than 0.5 s, such as shorter than 0.4 s. p.