EP0181890A1 - A low-light miniature flash light - Google Patents

A low-light miniature flash light

Info

Publication number
EP0181890A1
EP0181890A1 EP85902416A EP85902416A EP0181890A1 EP 0181890 A1 EP0181890 A1 EP 0181890A1 EP 85902416 A EP85902416 A EP 85902416A EP 85902416 A EP85902416 A EP 85902416A EP 0181890 A1 EP0181890 A1 EP 0181890A1
Authority
EP
European Patent Office
Prior art keywords
light
emitting diode
light emitting
casing
low
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP85902416A
Other languages
German (de)
French (fr)
Inventor
Ralph Lazic
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Commonwealth of Australia
Original Assignee
Commonwealth of Australia
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Commonwealth of Australia filed Critical Commonwealth of Australia
Publication of EP0181890A1 publication Critical patent/EP0181890A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21L—LIGHTING DEVICES OR SYSTEMS THEREOF, BEING PORTABLE OR SPECIALLY ADAPTED FOR TRANSPORTATION
    • F21L4/00—Electric lighting devices with self-contained electric batteries or cells
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
    • F21Y2115/00—Light-generating elements of semiconductor light sources
    • F21Y2115/10—Light-emitting diodes [LED]

Definitions

  • This invention relates to a low light miniature flash light, and in particular it relates to a flash light which is sufficiently economical in cell life to allow the unit to be discarded when the energising cells are exhausted.
  • Flash lights of many kinds are of course well known and these usually comprise a lamp having a filament energised by one or more cells held in a case and including switch means to allow the filament to be energised at required times, the cells being replaceable when exhausted.
  • Such flash lights are generally of relatively high brilliance and may be provided with reflectors or otherwise to help concentrate the beam from the light source, and more recently transistorised flash lights using a fluorescent tube are available.
  • the object of the present invention is to provide a small low intensity flash light which can be used for map reading, examination of areas where a strong beam is not required, and which is of relatively low cost and rugged to be reliable under adverse conditions, which can be used in the field and is waterproof.
  • the object can be achieved by using a throw-away construction which allows the torch to be discarded when the energising cells are exhausted.
  • Such a flash light which can be built to have a selected intensity when used in complete or semi-darkness whereby to minimise image retentivity in the eye, and can be used without attracting attention to make it useful to army or other personnel examining maps or the like which requires minimum scattering of light.
  • the device is also useful for signalling.
  • the invention comprises a low-light miniature flash light comprising a light source, battery means, and switch means connecting the light source with the bat-tery means, characterised as a throw-away package in which the light source is a light emitting diode connected by a resistor to the battery means all housed in and held by a resilient shrink fit casing arranged to allow the switch means to be actuated by pressure on the casing, the light emitting diode having a light-transmitting face projecting from the casing.
  • the flash light has a resilient supportive case and a simple switch.
  • a light emitting diode (LED) energised by cells through switch means and a resistance to control the current flow through the LED so that by selecting a suitable value the light intensity is selected.
  • the LEDs used are high efficiency types which give longer battery life for a given light output. Also LEDs are inherently rugged as well as economical, and the light-emitting face can be polished to a flat surface with minimum detection from the side of the flash light.
  • FIG. 1 is a perspective view of such a flash light using two energising cells
  • FIG. 2 is an enlarged side elevation of same with the outer case longitudinally sectioned.
  • the device comprises a pair of cells 1 and 2 which are oppositely orientated so that the positive terminal of one is at the end opposite to the positive terminal of the other.
  • the two cells are connected at one end to the LED 3 through a cathode lead 4 from the negative end of one of the cells, the lead 4 being soldered or otherwise secured permanently to this end of the cell, the anode lead 5 of the LED 3 being connected to the positive end of the other cell so that there is a connection from the negative end of one cell to the positive end of the other cell via the LED 3.
  • the negative end of the cell 2 is connected by a lead 6 to a resistor 7 the other end of which has its lead bent at the end to form a switch 8.
  • the cell 1 at the area of the switch 8 has its sheath removed to expose the positive outer wall of the cell, the lead being so bent that it can be deflected onto the body of the cell 1 to form a switch to make the necessaryy flow connection to energise the LED 3 through the resistor 7.
  • the cells 1 and 2 can have an insulating separator 11 between them, and the positive core of the cell 1 is exposed at 12 to be engaged by the lead 8.
  • a "Thick dual wall heat-shrink tubing with meltable adhesive" inner wall 9 is placed over the complete assembly and is shrunk into position to lock the assembly tightly together and to provide the necessary support for the LED 3 from the cells 1 and 2, while at the other end it is preferred to allow the tube 9 to extend beyond the cells 1 and 2 and to place an eyelet 10 through the wall of the tube.
  • the heat shrink tubing before the heat shrink tubing is applied it is advantageous to build up the LED with two layers of white heat shrink tubing to ensure an effective seal between the LEDs and the outer heat shrink tubing 9, and In this way a very small flash light is provided which is permanently encased in the tubing 9 after it is shrunk into position and, as well as holding the components together, and thus a completely sealed unit is provided which can be operated underwater and in other adverse conditions.
  • the two layers of white heat shrink material are designated 13 and 14, but it will be realised that a single white heat shrink tube could be used.
  • the face 15 is polished to be flat, but for some uses this may not be necessary. However, the flat face allows ready cleaning and ensures that even under adverse conditions, the maximum light is emitted.
  • the LED can be arranged by appropriate use of resistances to have a different current consumption, for example in the optimum range, of between 1 milliamp and 5 milliamps, and it will be realised that LEDs are available in various colours, thus making the colour of the emitted light readily selectable and, as said, that by using appropriate resistances the light intensity can be controlled and from this it follows that battery life is also controllable. It has been found that by reasonable use such a flash light can have a life of up to twelve months.
  • the unit is completely sealed and is of small dimension, such a flash light can be readily carried and is generally proof against shock or the ingress of moisture particularly as the switching means are also within the enclosing casing which because of its resilience, allows the switch to be actuated by simple pressure on the wall of the heat-shrink tubular casing.
  • these cells can be of larger capacity where a larger flash light is required, as higher power LEDs are being developed but generally the object is to provide a relatively small completely sealed unit with a light intensity such that it minimises image retentivity in the eye at night, making it suitable for use, for instance, where the user is avoiding detection.
  • the effect of image retentivity of eye at night is less severe if longer wavelength light is used, the eye recovering quicker from red than from green or yellow light.
  • the invention comprises a flash light having a light source connected through switch means to a cell or cells arranged to energise the light source, the flash light being characterised in that the light source is a LED and is connected to energising cell means through switch means and if necessary a resistance arranged to control flow through the LED to regulate the light emission.
  • the pair of cells are oppositely orientated with a light emitting diode connected across one end of the cells and the other end of one cell is connected to the bared case of the other cell through a resistance by a switch in the form of the tail of the resistance, bent so that it can be pressed against the negative outer case of one of the cells.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Radiation-Therapy Devices (AREA)
  • Arrangement Of Elements, Cooling, Sealing, Or The Like Of Lighting Devices (AREA)

Abstract

Torche miniature jetable de faible puissance lumineuse, la source de lumière étant une diode électroluminescente (3) reliée par un transistor (7) à une batterie (1, 2). Le boîtier (9) est une enveloppe résiliente à serrage permettant à un commutateur (8) d'être actionné par une pression sur l'enveloppe.Disposable miniature torch of low light power, the light source being a light-emitting diode (3) connected by a transistor (7) to a battery (1, 2). The housing (9) is a resilient tightening envelope allowing a switch (8) to be actuated by pressing on the envelope.

Description

A LOW-LIGHT MINIATURE FLASH LIGHT:
This invention relates to a low light miniature flash light, and in particular it relates to a flash light which is sufficiently economical in cell life to allow the unit to be discarded when the energising cells are exhausted.
Flash lights of many kinds are of course well known and these usually comprise a lamp having a filament energised by one or more cells held in a case and including switch means to allow the filament to be energised at required times, the cells being replaceable when exhausted.
Such flash lights are generally of relatively high brilliance and may be provided with reflectors or otherwise to help concentrate the beam from the light source, and more recently transistorised flash lights using a fluorescent tube are available.
It is known to use a low intensity light source for night-time viewing, see for instance the specification of United States Patent No. 4,409,643 of Livermore and Edwards assigned to the United States Department of Energy which uses a diode and lens, also.
The specification of United States Patent No. 4,808,261 of Polakoff which uses a light emitting diode electrically connected across a battery.
The object of the present invention is to provide a small low intensity flash light which can be used for map reading, examination of areas where a strong beam is not required, and which is of relatively low cost and rugged to be reliable under adverse conditions, which can be used in the field and is waterproof. The object can be achieved by using a throw-away construction which allows the torch to be discarded when the energising cells are exhausted.
Such a flash light which can be built to have a selected intensity when used in complete or semi-darkness whereby to minimise image retentivity in the eye, and can be used without attracting attention to make it useful to army or other personnel examining maps or the like which requires minimum scattering of light. The device is also useful for signalling.
The invention comprises a low-light miniature flash light comprising a light source, battery means, and switch means connecting the light source with the bat-tery means, characterised as a throw-away package in which the light source is a light emitting diode connected by a resistor to the battery means all housed in and held by a resilient shrink fit casing arranged to allow the switch means to be actuated by pressure on the casing, the light emitting diode having a light-transmitting face projecting from the casing. The flash light has a resilient supportive case and a simple switch.
Thus the objects are achieved according to this invention by using, instead of a filament type light source, a light emitting diode (LED) energised by cells through switch means and a resistance to control the current flow through the LED so that by selecting a suitable value the light intensity is selected. The LEDs used are high efficiency types which give longer battery life for a given light output. Also LEDs are inherently rugged as well as economical, and the light-emitting face can be polished to a flat surface with minimum detection from the side of the flash light.
Such a flash light can be variously constructed, but to enable the invention to be fully appreciated an embodiment will be described with reference to the accompanying drawings in which :-
FIG. 1 is a perspective view of such a flash light using two energising cells, and
FIG. 2 is an enlarged side elevation of same with the outer case longitudinally sectioned.
In the form illustrated in the drawings the device comprises a pair of cells 1 and 2 which are oppositely orientated so that the positive terminal of one is at the end opposite to the positive terminal of the other.
The two cells are connected at one end to the LED 3 through a cathode lead 4 from the negative end of one of the cells, the lead 4 being soldered or otherwise secured permanently to this end of the cell, the anode lead 5 of the LED 3 being connected to the positive end of the other cell so that there is a connection from the negative end of one cell to the positive end of the other cell via the LED 3.
The negative end of the cell 2 is connected by a lead 6 to a resistor 7 the other end of which has its lead bent at the end to form a switch 8. The cell 1 at the area of the switch 8 has its sheath removed to expose the positive outer wall of the cell, the lead being so bent that it can be deflected onto the body of the cell 1 to form a switch to make the necesary flow connection to energise the LED 3 through the resistor 7. The cells 1 and 2 can have an insulating separator 11 between them, and the positive core of the cell 1 is exposed at 12 to be engaged by the lead 8.
After this assembly is completed a "Thick dual wall heat-shrink tubing with meltable adhesive" inner wall 9 is placed over the complete assembly and is shrunk into position to lock the assembly tightly together and to provide the necessary support for the LED 3 from the cells 1 and 2, while at the other end it is preferred to allow the tube 9 to extend beyond the cells 1 and 2 and to place an eyelet 10 through the wall of the tube. However, before the heat shrink tubing is applied it is advantageous to build up the LED with two layers of white heat shrink tubing to ensure an effective seal between the LEDs and the outer heat shrink tubing 9, and In this way a very small flash light is provided which is permanently encased in the tubing 9 after it is shrunk into position and, as well as holding the components together, and thus a completely sealed unit is provided which can be operated underwater and in other adverse conditions. The two layers of white heat shrink material are designated 13 and 14, but it will be realised that a single white heat shrink tube could be used.
As referred to earlier herein to ensure that the light is not observable from the side of the flash light the face 15 is polished to be flat, but for some uses this may not be necessary. However, the flat face allows ready cleaning and ensures that even under adverse conditions, the maximum light is emitted.
The light of such a flash light is satisfactory because of the economic operation of a LED 3 as opposed to filament energisation as used hitherto, and light intensity and cell life is readily selectable during construction of the flash light.
As an example of the type of cell which can be used, these can be miniature alkaline cells as used for instance as a group in the well known 9 volt batteries. Two of these cells are required to produce the correct operating condition for the LED (red, yellow or green) i.e., each alkaline cell produces 1.5v (per cell). Two of these cells connected in series produces 3v which is of sufficient magnitude to operate red, yellow or green LEDs (the requirement being that the excitation voltage be greater than 1.6v for red LED and greater than 2.0v for yellow or green). Alternatively, only one lithium cell would be required as these produce 3v per cell. These cells have the advantage of very long shelf life 5 to 10 years (compared to 1 to 2 years for alkaline cells) but have the disadvantage of higher initial cost. The modest current requirement is due to the high efficiency nature of these LEDs as a light emitting source.
As an example the LED can be arranged by appropriate use of resistances to have a different current consumption, for example in the optimum range, of between 1 milliamp and 5 milliamps, and it will be realised that LEDs are available in various colours, thus making the colour of the emitted light readily selectable and, as said, that by using appropriate resistances the light intensity can be controlled and from this it follows that battery life is also controllable. It has been found that by reasonable use such a flash light can have a life of up to twelve months.
Moreover, because the unit is completely sealed and is of small dimension, such a flash light can be readily carried and is generally proof against shock or the ingress of moisture particularly as the switching means are also within the enclosing casing which because of its resilience, allows the switch to be actuated by simple pressure on the wall of the heat-shrink tubular casing.
It will be realised that these cells can be of larger capacity where a larger flash light is required, as higher power LEDs are being developed but generally the object is to provide a relatively small completely sealed unit with a light intensity such that it minimises image retentivity in the eye at night, making it suitable for use, for instance, where the user is avoiding detection. The effect of image retentivity of eye at night is less severe if longer wavelength light is used, the eye recovering quicker from red than from green or yellow light.
From the foregoing it will be realised that the invention comprises a flash light having a light source connected through switch means to a cell or cells arranged to energise the light source, the flash light being characterised in that the light source is a LED and is connected to energising cell means through switch means and if necessary a resistance arranged to control flow through the LED to regulate the light emission. According to the preferred construction described the pair of cells are oppositely orientated with a light emitting diode connected across one end of the cells and the other end of one cell is connected to the bared case of the other cell through a resistance by a switch in the form of the tail of the resistance, bent so that it can be pressed against the negative outer case of one of the cells.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:-
1. A low-light miniature flash light comprising a light source, battery means, and switch means connecting said light source with said battery means, characterised in that the flash light is formed as a throw-away package in which the light source is a light emitting diode connected by a resistor to the said battery means all housed in and held by a resilient shrink fit casing arranged to allow the switch means to be actuated by pressure on said casing, said light emitting diode having a light-transmitting face projecting from said casing.
2. A low-light miniature flash light according to Claim 1 further characterised in that the light emitting diode is itself housed in at least a first tubular layer of white material engaged by the heat shrink casing, and further characterised in that the light emitting face of the light emitting diode is polished to be flat whereby to enhance light transmission.
3. A lew-light miniature flash light according to Claim 1 or 2 further characterised in that the said battery means comprise first and second battery cells placed side by side with the light emitting diode adjacent one end thereof and electrically connected across the said cells, and by a resistor connected to the other end of the said first cell by a tail extending from the said resistor, a second tail at the opposite end of the said resistor being arranged to lie adjacent to an exposed part of the case of the said second cell to contact the said cell when the said resilient casing is depressed to energise the said light emitting diode.
4. A low-light miniature flash light comprising a light source (3), battery means (1-2), and switch means (8) connecting said light source (3) with said battery means (1-2), characterised in that the flash light is formed as a throw-away package comprising. a light emitting diode (3) forming the said light source, battery means (1-2) interconnected electrically to energise said light emitting diode (3), a resilient shrink fit casing (9) encasing the said battery means (1-2) and light emitting diode but allowing a light emitting face (15) of the said light emitting diode (3) to be exposed through said casing (9), switch means (1-8) in the said electrical connecting means arranged to be actuated by pressure on said casing (9) to complete the circuit to the light emitting diode (3) when the said case is depressed.
5. A low-light miniature flash light according to Claim 4 further characterised by at least a first tubular layer (14) of light reflective material engaged by the heat shrink casing (9) to enhance light transmission.
6. A low-light flash light according to Claim 5 wherein two layers (13-14) of heat shrink material are used.
7. A low-light miniature flash light according to any one of preceding claims 4, 5 or 6 characterised in that the face (15) of the said light emitting diode (3), and optionally the layers (13-14) of light reflective material, are polished to be flat whereby to enhance light transmission.
8. A low-light miniature flash light according to Claim 4 characterised in that the said battery means (1-2) comprise first and second battery cells placed side by side but oppositely polarised with the light emitting diode (3) adjacent one end thereof and electrically connected across the said cells at contiguous ends thereof, and by a resistor (7) connected to the other end of the said first cell (1) by a tail (6) extending from the said resistor (7), a second tail (8) at the opposite end of the said resistor (7) being arranged to lie adjacent to an exposed part of the case (12) of the said second cell (2) to contact the said cell (2) when the said resilient casing (9) is depressed adjacent the said second tail (8) whereby to energise the said light emitting diode.
9. A low-light emitting diode constructed and operating substantially as described and illustrated in the accompanying drawings.
EP85902416A 1984-05-16 1985-05-13 A low-light miniature flash light Withdrawn EP0181890A1 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
AU5025/84 1984-05-16
AU502584 1984-05-16
AU519884 1984-05-25
AU5198/84 1984-05-25

Publications (1)

Publication Number Publication Date
EP0181890A1 true EP0181890A1 (en) 1986-05-28

Family

ID=25611038

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85902416A Withdrawn EP0181890A1 (en) 1984-05-16 1985-05-13 A low-light miniature flash light

Country Status (3)

Country Link
EP (1) EP0181890A1 (en)
IL (1) IL75209A0 (en)
WO (1) WO1985005432A1 (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4774643A (en) * 1986-11-17 1988-09-27 Diagin, Inc. Illuminator for radiation dosimeter and method of manufacture
GB2220735A (en) * 1988-07-04 1990-01-17 Geoffrey Philip Beastall Light emitting diode torch
GB9126299D0 (en) * 1991-12-09 1992-02-12 Hi Tech Batteries Ltd A torch

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2483820A (en) * 1946-04-09 1949-10-04 Raymond L Falge Flashlight
US2632094A (en) * 1949-02-07 1953-03-17 Robert G Akerley Flashlight having a sealed flexible casing
US2694772A (en) * 1949-12-14 1954-11-16 Gelardin Albert Flashlight with hermetically sealed casing
US3795830A (en) * 1972-08-17 1974-03-05 Shelton J Led slidebase switchboard lamp
US4310873A (en) * 1978-06-06 1982-01-12 Bean Stanley R Key hole light illuminator
US4228484A (en) * 1978-12-04 1980-10-14 Johnstone Malcolm D LED flasher for battery cell-powered lamp
US4242724A (en) * 1979-04-27 1980-12-30 Stone Wilfred S Disposable floating flashlight

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8505432A1 *

Also Published As

Publication number Publication date
IL75209A0 (en) 1985-09-29
WO1985005432A1 (en) 1985-12-05

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