Title: LED flashlight
Abstract: A flashlight configured to durably provide an effective beam of light for extended periods of time. The flashlight features a high-power, directed LED configured to produce a divergent beam of light that is characterized by an optical directivity angle extending from a vertex point. The flashlight includes a lens having a first portion forming a convergent lens, where the LED is located such that its vertex point coincides with the lens' focal point. The convergent lens is sized and positioned such that substantially all of the directed light from the LED passes through the convergent lens portion to emerge in a first beam of parallel light. The LED emits additional light through a tip. A parabolic reflector has the tip at its focal point to reflects the additional light into a second beam of parallel light that is parallel to and surrounding the first beam, thus forming a single and more efficient useful beam. The LED and parabolic reflector are formed into an illuminator assembly that is contained within a housing of the flashlight so as to hold the LED in alignment with its preferred position with respect to the parabolic reflector.
Patent Number: 6,932,490 Issued on 08/23/2005 to Emil, et al.
| Inventors:
|
Emil; Chan Ka Ming (Sunshine, HK);
Ellis; Hon Siu Cheong (Sunshine, HK)
|
| Assignee:
|
The Brinkmann Corporation (Dallas, TX)
|
| Appl. No.:
|
606118 |
| Filed:
|
June 25, 2003 |
| Current U.S. Class: |
362/202; 362/200; 362/308; 362/328; 257/98 |
| Intern'l Class: |
F21L 004/04 |
| Field of Search: |
362/200,201,202,204,205,208,800,240,241,308,309,310,336,346,311,327,328,307
359/721
257/98
|
References Cited [Referenced By]
U.S. Patent Documents
| 1219583 | Mar., 1917 | Perry.
| |
| 2362176 | Nov., 1944 | Swanson.
| |
| 2469080 | May., 1949 | Rosin et al.
| |
| 4336580 | Jun., 1982 | Mouyard et al.
| |
| 4530040 | Jul., 1985 | Petterson.
| |
| 4698730 | Oct., 1987 | Sakai et al.
| |
| 4733335 | Mar., 1988 | Serizawa et al.
| |
| 4853531 | Aug., 1989 | Rejc.
| |
| 4920404 | Apr., 1990 | Shrimali et al.
| |
| 4920469 | Apr., 1990 | Harding.
| |
| 5093768 | Mar., 1992 | Ohe.
| |
| 5490045 | Feb., 1996 | Lindner.
| |
| 5534718 | Jul., 1996 | Chang.
| |
| 5698866 | Dec., 1997 | Doiron et al.
| |
| 5803579 | Sep., 1998 | Turnbull et al.
| |
| 5894196 | Apr., 1999 | McDermott.
| |
| 6220719 | Apr., 2001 | Vetorino et al.
| |
| 6244723 | Jun., 2001 | Talamo.
| |
| 6260994 | Jul., 2001 | Matsumoto et al.
| |
| 6361190 | Mar., 2002 | McDermott.
| |
| 6585391 | Jul., 2003 | Koch et al.
| |
| 6686691 | Feb., 2004 | Mueller et al.
| |
| 6814463 | Nov., 2004 | Mele.
| |
| Foreign Patent Documents |
| 810256 | May., 1959 | GB.
| |
Primary Examiner: Husar; Stephen
Assistant Examiner: Sawhney; Hargobind S.
Attorney, Agent or Firm: Sheppard, Mullin, Richter & HamptonLLP
Parent Case Text
This is a continuation of U.S. patent application Ser. No. 09/637,344, filed
Aug. 11, 2000, which has been abandoned.
Claims
1. A flashlight, comprising:
an illuminator assembly including an LED, a printed circuit board, a flange,
and a parabolic reflector;
a lens having a convergent portion, a nonconvergent portion, and a lens flange,
wherein the convergent portion is characterized by a focal point; and
a housing conformingly receiving the illuminator assembly so as to contain the
illuminator assembly within the housing;
wherein associated circuitry is mounted on the printed circuit board, the associated
circuitry configured to provide power to the LED;
wherein the LED has a light emitting element, a parabolic micro-reflector and
a transparent tip, the LED being mounted in the printed circuit board and configured
to emit light from its light emitting element and produce by reflection from the
parabolic micro-reflector a divergent beam of light that is characterized by an
optical directivity angle extending from a vertex point, and also to produce additional
light extending in a direction outside of the divergent beam of light and emanating
from the tip of the LED;
wherein the parabolic reflector is connected to the printed circuit board such
that the focal point of the parabolic reflector coincides with the transparent
tip;
wherein the flange is configured to engage the lens flange to position the LED
so that the light emitting element is positioned at the focal point of the convergent
portion and the divergent beam is centered on the focal center point of the convergent
portion;
wherein substantially all of the divergent beam of light from the LED passes
through the convergent lens to emerge in a first beam of parallel light; and
wherein the parabolic reflector reflects at least a portion of the additional
light into a second beam of parallel light that is parallel to the first beam of
parallel light and extending through the nonconvergent portion of the lens.
2. The flashlight of claim 1, and further comprising a body portion defining
one or more battery compartments configured to receive one or more batteries, wherein:
the illuminator assembly is conformingly received by the body portion; and
the housing conformingly receiving the body portion so as to contain the body
portion within the housing.
3. The flashlight of claim 1 wherein:
the portion of the lens that is convergent comprises a focal center point and
is characterized by a convergence diameter D,
wherein the distance between the focal point and the focal center point defines
a focal distance L, and wherein the relationship between the convergence diameter
D, the focal distance L, and the optical directivity angle A is described by the
relation D≧2L Tan (A/2).
4. The flashlight of claim 1, wherein the directivity angle is about 20°.
5. The flashlight of claim 1, wherein the non-convergent portion of the lens
surrounds the convergent portion of the lens.
6. The flashlight of claim 1, and further comprising:
a switch;
at least one battery compartment configured to hold at least one battery, the
battery compartment having contacts that are connected in a circuit that includes
the LED and the switch such that the switch can close and open the circuit to energize
and deenergize the LED when the battery is installed in the battery compartment;
and
a housing configured to house the LED, the lens, the switch and the battery compartment.
7. A flashlight comprising:
a lens having a convergent portion, a nonconvergent portion, and a lens flange,
wherein the convergent portion is characterized by a focal point;
an illuminator assembly including an LED, a flange, and a parabolic reflector,
the LED having a light emitting element and a transparent tip, and the LED connected
to a structure containing circuitry connecting the LED with a battery, wherein
the LED emits a divergent beam of light that is characterized by an optical directivity
angle extending from a vertex point, and wherein the LED emits additional light
extending in a direction outside of the divergent beam of light and emanating from
the tip of the LED; and
a housing conformingly receiving the illuminator assembly so as to contain the
illuminator assembly within the housing,
wherein the parabolic reflector is connected to the circuitry-containing structure
such that the focal point of the parabolic reflector coincides with the transparent
tip of the LED,
wherein the flange is configured to engage the lens flange to position the LED
so that the light emitting element is positioned at the focal point of the convergent
portion of the lens and the divergent beam of light is centered on the focal center
point of the convergent portion of the lens,
wherein a beam of light from the LED passes through the convergent portion of
the lens to emerge in a first beam of parallel light; and
wherein the parabolic reflector reflects at least a portion of the additional
light into a second beam of parallel light that is parallel to the first beam of
parallel light and extends through the nonconvergent portion of the lens.
8. The flashlight of claim 7, wherein the non-convergent portion of the lens
surrounds the convergent portion of the lens.
9. The flashlight of claim 7, and further comprising:
a switch;
at least one battery compartment configured to hold at least one battery, the
battery compartment having at least one contact that is connected in a circuit
that includes the LED and the switch such that the switch can close and open the
circuit to energize and deenergize the LED when the battery is installed in the
battery compartment; and
a housing configured to house the LED, the lens, the switch and the battery compartment.
10. The flashlight of claim 7, wherein the divergent beam of light passes substantially
through the convergent portion of the lens to form a first parallel beam of light.
11. A flashlight comprising:
an illuminator assembly including an LED, a flange, and a parabolic reflector,
a lens having a convergent portion, a nonconvergent portion, and a lens flange,
wherein the convergent portion is characterized by a focal point; and
a housing conformingly receiving the illuminator assembly so as to contain the
illuminator assembly within the housing;
wherein the LED has a light emitting element, a parabolic micro-reflector and
a transparent tip, and the LED is mounted on a circuit board and configured to
emit light from its light emitting element and produce by reflection from the parabolic
micro-reflector a divergent beam of light that is characterized by an optical directivity
angle extending from a vertex point, and also to produce additional light extending
in a direction outside of the divergent beam of light and emanating from the tip
of the LED;
wherein the parabolic reflector is positioned such that the focal point of the
parabolic reflector coincides with the transparent tip of the LED;
wherein the flange is configured to engage the lens flange to position the LED
so that the light emitting element is positioned at the focal point of the convergent
portion of the lens and the divergent beam is centered on the focal center point
of the convergent portion of the lens;
wherein the divergent beam of light from the LED passes through the convergent
lens to emerge in a first beam of parallel light; and
wherein the parabolic reflector reflects at least a portion of the additional
light into a second beam of parallel light that is parallel to the first beam of
parallel light and extending through the nonconvergent portion of the lens.
12. The flashlight of claim 11, wherein the non-convergent portion of the lens
surrounds the convergent portion of the lens.
13. The flashlight of claim 11, and further comprising:
a switch;
at least one battery compartment configured to hold at least one battery, the
battery compartment having at least one contact that is connected in a circuit
that includes the LED and the switch such that the switch can close and open the
circuit to energize and deenergize the LED when the battery is installed in the
battery compartment; and
a housing configured to house the LED, the lens, the switch and the battery compartment.
14. A flashlight comprising:
a lens having a convergent portion, a nonconvergent portion, and a lens flange,
wherein the convergent portion is characterized by a focal point;
an illuminator assembly including a LED, a flange, a mounting structure and a
parabolic reflector, the LED characterized by emitting a divergent beam of light,
the LED and the parabolic reflector connected to the mounting structure, and the
focal point of the parabolic reflector coinciding with a light emitting area of
the LED;
a housing conformingly receiving the illuminator assembly so as to contain the
illuminator assembly and the lens within the housing;
wherein the flange is configured to engage the lens flange to position the LED
so that the light emitting area of the LED is positioned at the focal point of
the convergent portion of the lens,
wherein the divergent beam of light from the LED passes through the convergent
portion of the lens to emerge in a first beam of parallel light, and
wherein the parabolic reflector reflects light from the divergent light emitting
area of the LED into a second beam of parallel light that is parallel to the first
parallel beam and exits through the nonconvergent portion of the lens.
15. The flashlight of claim 14, wherein the non-convergent portion of the lens
surrounds the convergent portion of the lens.
16. The flashlight of claim 14, and further comprising:
a switch;
at least one battery compartment configured to hold at least one battery, the
battery compartment having at least one contact that is connected in a circuit
that includes the LED and the switch such that the switch can close and open the
circuit to energize and deenergize the LED when the battery is installed in the
battery compartment; and
a housing configured to house the LED, the lens, the switch and the battery compartment.
17. The flashlight of claim 14, wherein the divergent beam of light passes substantially
through the convergent portion of the lens to form a first parallel beam of light.
Description
BACKGROUND OF THE INVENTION
The present invention pertains to the field of portable or battery-operated lighting
products. More particularly, this invention relates to hand-held, battery operated flashlights.
Flashlights are used to cover a variety of household, workplace and recreational
needs. Common-flashlights often include a head that contains a relatively fragile
incandescent bulb, and a cylindrical body configured to hold batteries. A switch,
commonly mounted in the body, completes a circuit between the batteries and the
bulb. A parabolic mirror or reflector is located within the head, with the filament(s)
of the bulb positioned at the focal point of the mirror. The mirror directs rays
of light from the filament forward in a parallel direction, creating a useful beam,
as depicted in FIG.
1A. In some cases, such flashlights are provided with
rubber o-rings to form a water-tight seal on the flashlight.
Many flashlights are stored without usage for great periods of time, and can
be then called upon to provide light for long periods with little notice. Other
flashlights are used frequently, and can be subject to significant environmental
extremes such as shock and temperature. In either case, failure of the flashlight's
fragile bulb is an all-to-frequent occurrence, leaving a user without a useful
light source. Time efficiency often dictates that the entire flashlight, rather
than just the bulb, be replaced, making the loss of a bulb relatively expensive.
As much as 50% of the light produced by the filament will miss the parabolic
mirror
(in either a forward or rearward direction), causing a large portion of the light
to be widely radiated out in many directions, as depicted in FIG.
1B. While
this peripheral light is sometimes useful, it is nothing but wasted glare in many
situations. Other common problems experienced by such flashlights include batteries
that do not provide light for an adequately extended period, particularly after
the flashlight has been in use or in storage. A further problem is that if the
bulb filaments are not precisely positioned at the focal point of the parabolic
mirror, the light striking the mirror will not be directed in a parallel beam,
further reducing the effectiveness and efficiency of the flashlight.
Accordingly, there has existed a definite need for a durable flashlight
configured to provide, an effective useful beam for an extended period, particularly
after extended storage. The present invention satisfies these and other needs,
and provides further related advantages.
SUMMARY OF THE INVENTION
The present invention provides a flashlight configured to durably provide an
effective useful beam of light for extended periods. The flashlight will typically
have low power requirements, and will therefore last for extended periods on a
given set of batteries. Because of the low power requirements, it will generally
function on the limited power available after a battery has been stored for an
extended period.
The flashlight features a high-power, directed LED configured to produce a divergent
beam of light characterized by an optical directivity angle extending from a vertex
point. Because the flashlight preferably derives all its illumination from the
LED, the flashlight will typically have low power requirements and be significantly
more durable than a flashlight deriving its light from an incandescent bulb.
Another feature of the invention is that the flashlight includes a lens having
a first portion that is convergent, where the LED is located such that its vertex
point coincides with the lens' focal point. This feature provides for the divergent
beam of light to be focused into a useful beam of parallel light, providing for
efficient use of the often-limited light available from an LED. Preferably, the
convergent lens is sized and positioned such that substantially all of the directed
light from the LED passes through the convergent lens portion to emerge in a first
beam of parallel light.
Yet another feature of the invention is that the flashlight also includes a parabolic
reflector. The LED emits additional light through a tip, and the tip is located
at a focal point of the parabolic reflector. An advantage of this feature is that
at least some, or preferably a substantial portion of the additional light strikes
the parabolic reflector to form a second beam of parallel light. The second beam
of parallel light preferably passes through a preferably flat lens that does not
change the overall direction of the second beam. The second beam is preferably
parallel to and surrounding the first beam, thus forming a single and more efficient
useful beam.
The invention also features an illuminator assembly contained within a housing
of the flashlight. The illuminator assembly includes both the LED and the parabolic
reflector. This feature advantageously provides for the LED to be held substantially
in its preferred position with respect to the parabolic reflector.
Other features and advantages of the invention will become apparent from the
following detailed description of the preferred embodiments, taken with the accompanying
drawings, which illustrate, by way of example, the principals of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is a schematic representation of a useful beam produced by a typical
bulb in an ordinary, prior-art flashlight.
FIG. 1B is a schematic representation of wasted glare produced by a typical
bulb in an ordinary, prior-art flashlight.
FIG. 2 is an exploded perspective view of a flashlight embodying features of
the present invention.
FIG. 3A is a front elevational view of the flashlight depicted in FIG. 2.
FIG. 3B is a side elevational view of the flashlight depicted in FIG. 2.
FIG. 3C is a rear elevational view of the flashlight depicted in FIG. 2.
FIG. 4A is a plan cross-section view of the flashlight depicted in FIG. 2.
FIG. 4B is an elevational cross-section view of the flashlight depicted in FIG. 2.
FIG. 5 is a side elevational view of a directional LED used in the flashlight
depicted in FIG. 2.
FIGS. 6A and 6B are front and side elevational views, respectively, of a lens
used in the flashlight depicted in FIG. 2.
FIG. 7A is a side elevational view of a forward portion of the flashlight used
in the flashlight depicted in FIG. 2, depicting the directed light from the LED
being made parallel by the lens.
FIG. 7B is a side elevational view of nondirected light being emitted by a directional
LED due to internal reflection.
FIG. 7C is a side elevational, view of a forward portion of the flashlight used
in the flashlight depicted in FIG. 2, depicting a significant portion of the emitted
non-directional light being made parallel by a parabolic mirror.
FIG. 7D is a side elevational view of a forward portion of the flashlight used
in the flashlight depicted in FIG. 2, depicting both the directed LED light and
a significant portion of the emitted non-directional light being made parallel.
FIG. 8 presents specifications of a preferred LED
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A flashlight
10 according to the present invention is shown in FIGS. 2,
3A-
3C and
4A-
4B. The flashlight includes a front housing
portion
12, a lens
14, an illuminator assembly
16, a body
portion
18, a switch assembly
20 and a rear housing portion
22.
The front housing portion is a hollow, approximately cylindrical tube with a forward-facing
orifice
30 at a front end
32 and a threaded, rearward-facing opening
34 at a rear end
36. The rear housing portion is a hollow, approximately
cylindrical tube with a threaded, forward-facing opening
40 at a front end
42 and a rearward facing orifice
44 at a rear end
46. The
rear end of the front housing portion and the front end of the rear housing portion
are configured to threadedly engage each other, forming a cylindrical, hollow housing
to contain the lens, illuminator assembly, body portion and switch assembly.
The flashlight
10 is configured with a first rubber o-ring
50 conformingly
received between the lens
16 and the front end
32 of the front housing
portion
12, to form a watertight seal over the forward-facing orifice
30.
Likewise, the flashlight
10 is configured with a rubber cap
52 conformingly
received between the lens switch assembly
20 and the rear end
46
of the rear housing portion
22, to form a watertight seal over the rearward-facing
orifice
44. Additionally, the flashlight is configured with a second o-ring
54 between the rear end
36 of the front housing portion and the front
end
42 of the rear housing portion
22, forming a watertight seal
between the front and rear housing portions. Thus, the housing (i.e., the combined
front and rear housing portions) is watertight.
With reference to FIGS. 4A,
4B and
5, the illuminator assembly
16 has a high-power, white LED
60. Preferably the LED is the only
light source in the flashlight, as preferably no bulb is present. The LED has a
filament
62 that produces rays of light when energized. The LED also has
a built-in, parabolic micro-reflector
63 that directs a significant portion
(preferably more than 50%) of the filaments light rays in a divergent beam
64
from a vertex point through a transparent tip
66 of the LED over a directivity
angle
68, preferably of 20 degrees. The vertex point is normally the location
of the filament. Preferably around 10% of the light from the filament is emitted
directly into the divergent beam without first reflecting off the micro reflector.
A preferred LED is the High-power White LED, NSPW500BS, by NICHIA CORPORATION
of
Japan. It includes stoppers to aid in positioning the LED, and has a preferred
electrical and optical characteristics, as well as preferred light directivity.
The characteristics of the High-power White LED, NSPW500BS, by NICHIA CORPORATION
are depicted in FIG.
8.
With reference to FIGS. 6A and 6B, the lens
14 is a transparent body
having a circular flat portion
80 surrounding a concentric, circular, convergent-lens
portion
82. The convergent-lens portion forms a biconvex lens having a focal
point
84 on each side of the convergent-lens portion, each focal point being
a focal distance away from a focal center point
86 of the convergent-lens
portion. A flange
88 surrounds the flat portion
80, adding rigidity
to the lens in the vicinity where it will compress the first o-ring
50 against
the forward end
32 of the front housing portion
12 (see, FIG.
2).
Preferably the lens is made of acrylic plastic by injection molding.
As depicted in FIGS. 2 and 7A, besides the LED
60, the illuminator assembly
16 includes a flange
90, a parabolic portion
92, support legs
94, and a printed circuit board
96 associated circuitry
98
configured to make the LED compatible with battery power levels that are available
in the flashlight. A parabolic inner face
100 of the parabolic portion
92
is a reflective, preferably mirror-like surface, having a focal point. Likewise,
an inner face
102 of the illuminator assembly's flange
90 is a reflective,
preferably mirror-like surface.
The illuminator assembly's flange
90 is sized and shaped to be conformingly
received within the lens' flange
88 and against a peripheral portion of
the lens' circular flat portion
80, thereby serving to position the LED
60 with respect to the lens' convergent-lens portion
82. In particular,
the LED's filament
62 is positioned at the focal point
84 of the
convergent-lens portion
82, and the divergent beam
64 is centered
on the focal center point
86 of the lens. Additionally, the convergent-lens
portion
82 is sized such that the outer limits of the beam preferably pass
through the convergent-lens portion, and most preferably through a periphery
104
of the convergent-lens portion. In other words, the relationship between the diameter
of the convergent-lens portion D, the focal distance L, and the directivity angle
68 is preferably stated as follows:
D≧2
LTan(
A/2)
Most preferably the above equation is an equality. As a result of the above-described
configuration, a divergent beam
64 produced by the LED
60 will pass
through the convergent-lens portion
82 to become a first parallel beam
110
of light, having a diameter of D, as shown in FIG.
7A.
As seen in FIG. 7B, some light emitted by the LED's filament
62 does not
get directed by the micro reflector
63 into the divergent beam, and does
not enter the divergent beam directly. Instead, after total internal reflection,
it reaches the transparent tip
66 and exits the LED
60 in a direction
extending, outside the divergent beam. This is typically accented by passing through
the tip at an angle not normal to the surface of the tip at that location, causing
the light to refract to an angle further outside the divergent beam.
With reference to FIGS. 7B and 7C, a, significant portion of this side-emitted
light
120 extends from the tip
66 of the LED
60 toward the
reflective inner face
100 of the parabolic portion
92. The illuminator
assembly
16 is configured such that the tip of the LED is located at the
focal point of the parabolic surface. Thus, the side-emitted light
120 that
strikes the inner face
100 of the parabolic portion
92 reflects to
form a second parallel beam of light
122.
As seen in FIG. 7D, preferably the parabolic inner face,
100 is sized
and
positioned such that the second parallel beam
122 is parallel to the first
parallel beam
110. Likewise, preferably the parabolic inner face
100
is sized and positioned such that light emitted in a direction normal
124
to the center of the directed beam reflects off the inner face and then passes
through the circular flat portion
80 immediately outside the periphery
104
of the convergent-lens portion
82. Thus, most of the light produced by the
LED, and preferably more than 90% of the light, will be directed in a parallel,
useful beam.
Because such a large portion of the generated light is in the useful beam,
the total amount of light emitted by the LED's filament (which is typically substantially
less than that of an incandescent bulb) is adequate to produce a useful beam. Furthermore,
the LED uses substantially less energy, extending battery life of the flashlight
by a substantial margin, preferably to at least 50 hours with two AA batteries.
This is roughly 20 times the battery life of common flashlights. Even after extended
storage, the LED can continue to function on the reduced battery power that is
available. Furthermore, because LEDs are not as fragile and short lived as incandescent
bulbs, the flashlight preferably has an effectively infinite bulb life (up to approximately
100,000 hours) with high durability and little likelihood of LED failure due to
rough handling.
Returning to FIGS. 2,
4A and
4B, the parabolic portion
92
is supported with respect to the circuit board
96 by the support legs
94.
The LED
60 is mounted directly in the circuit board, and thus the support
legs and circuit board contribute to holding the LED in position with respect to
the parabolic portion and the lens
14. The circuit board and its associated
circuitry
98 provide the power to energize the LED.
The circuit board is sized and otherwise configured to be received within a holding-cavity
128 in the body portion
18. The power is provided to the circuit
board through lead wires
130 connecting to contacts
132 in the body
portion
18. The body portion includes compartments
134 for holding
two batteries
136, where the contacts are positioned in the compartments
to contact the batteries.
The circuit including the two batteries
136, the circuit board
96
and its associated circuitry
98 and the LED
60 also passes through
two contacts
140 on the switch assembly
20. When a person depresses
the rubber cap
52, which extends through the rearward facing orifice
44,
the switch assembly alternates between opening and closing the circuit, thereby
alternating the flashlight between an "on" and an "off" state.
From the foregoing description, it will be appreciated that the present invention
provides a durable flashlight, which is water and shock resistant, configured to
provide an effective useful beam for an extended period, particularly after extended
storage. While a particular form of the invention has been illustrated and described,
it will be apparent that various modifications can be made without departing from
the spirit and scope of the invention. Thus, although the invention has been described
in detail with reference only to the preferred embodiments, those having ordinary
skill in the art will appreciate that various modifications can be made without
departing from the invention. Accordingly, the invention is not intended to be
limited, and is defined with reference to the following claims.
*
