WO2009029575A1

WO2009029575A1 - Light emitting diode lamp free of melatonin-suppressing radiation

Info

Publication number: WO2009029575A1
Application number: PCT/US2008/074208
Authority: WO
Inventors: Martin C. Alpert; Edward F. Carome; Richard L. Hansler; Vilnis E. Kubulnis; James L. Spayer
Original assignee: Photonic Developments Llc
Priority date: 2007-08-24
Filing date: 2008-08-25
Publication date: 2009-03-05

Abstract

An electric lamp includes a first light source and a second light source and control circuitry configured to selectively energize the first light source and the second light source. The first light source is configured to produce white light and the second light source is configured to produce light that appears to be substantially white light, but does not include portions of the wavelength spectrum that are most effective in suppressing the production of melatonin.

Description

LIGHT EMITTING DIODE LAMP FREE OF MELATONIN-SUPPRESSING

RADIATION

RELATED APPLICATION DATA

The present application claims benefit of U.S. Provisional Application Serial Nos. 60/965,950, filed August 24, 2007, and 60/995,996, filed October 1, 2007, the disclosures of which are herein incorporated by reference in its entireties.

TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to an illumination source, and more particularly, to a light emitting diode (LED) lamp configured to produce light that is free of melatonin-suppressing radiation.

DESCRIPTION OF RELATED ART

Humans and animals live under conditions of natural illumination. Natural light is a dynamic light condition that exhibits daily and seasonal changes in intensity, color spectrum, and duration. Many species of plants, animals, and microorganisms have biological processes that are attuned to environmental illumination patterns and lighting conditions. It is well known that changes in these illumination patterns and lighting conditions can have significant physiological and behavioral effects.

Changes in illumination patterns and lighting conditions have been found to have dramatic effects on the physiology, psychology, and mood of humans. For instance, in certain geographical areas, an estimated 20% of the human population may be affected by winter depression, or seasonal affective disorder ("SAD"), a condition associated with reduced exposure to natural light during the winter season. Symptoms of this disorder can include fatigue, depression, and changes in appetite and sleep patterns. Recent research has revealed that extended exposure to bright light can help alleviate many of the symptoms of SAD in some patients. Most living creatures, including humans, have an internal biological clock that controls many life functions in rhythmic patterns, which include 24-hour patterns known as circadian rhythms. These biological rhythms help to regulate a wide variety of biological processes. A number of maladies, such as jet lag, certain mood disorders, and sleep disorders, are associated with a disruption in these intrinsic rhythms. Since environmental illumination patterns are believed to play a role in regulating the internal clock of humans and other organisms, various forms of light therapy have been used to treat many of these conditions.

Ordinary lights also can be damaging to health because they produce the blue rays that have been found to cause melatonin suppression, if used during the time when melatonin would be present. Typically, this is the period in the evening preceding normal bedtime. While melatonin is a hormone that promotes sleep, it also is believed to be a powerful cancer fighter. Melatonin has other health benefits as well.

SUMMARY

To reduce the melatonin-suppressing effects found in ordinary lighting, an electric lamp is provided with a light source configured to produce light in a wavelength range that does not include the portion of the wavelength spectrum most effective in suppressing the production of melatonin. One aspect of the disclosed technology relates to an electric lamp that includes a first light source configured to produce white light; a second light source configured to produce light in a wavelength range that does not include a portion of the wavelength spectrum most effective in suppressing the production of melatonin; and circuitry configured to selectively energize the first light source and/or the second light source.

According to another aspect, the circuitry is configured to selectively energize the first light source or the second light source the depending on the time of day.

According to another aspect, the second light source is configured to produce light that visually appears to be substantially white, but does not include a portion of the wavelength spectrum most effective in suppressing the production of melatonin.

According to another aspect, the second light source is configured to produce light having wavelengths longer than about 530 nanometers.

According to another aspect, the first light source comprises a light emitting diode (LED) chip that produces short wavelength visible light and a phosphor positioned to receive at least a portion of the short wavelength light from the LED chip, wherein the phosphor is configured to emit light in the balance of the visual spectrum upon receiving the short wavelength light.

According to another aspect, the first light source comprises a light emitting diode (LED) chip that produces light having a wavelength of about 370 nanometers to about 500 nanometers and a phosphor positioned to receive at least a portion of the light from the LED chip, wherein the phosphor is configured to emit light having wavelengths greater than about 530 nanometers.

According to another aspect, the second light source comprises a LED chip that produces ultraviolet (UV) or very short wavelength light and a phosphor positioned to receive the UV or very short wavelength light from the LED chip, wherein the phosphor is configured to emit light at wavelengths longer than about 530 nanometers.

According to another aspect, the second source is the same source as the first source in combination with a movable filter that blocks blue light having wavelengths shorter than about 530 nanometers.

According to another aspect, the circuitry includes a switch electrically coupled to the first light source and the second light source.

According to another aspect, the switch is a manual switch configured to be manipulated by a user.

According to another aspect, the circuitry includes a controller configured to actuate the switch.

According to another aspect, the circuitry includes a timer coupled to the switch, wherein the timer is configured to actuate the switch. According to another aspect, the circuitry includes a radio frequency (RF) switch operable to receive a RF actuation signal from a remote source or an infrared switch operable to receive an infrared actuation signal from a remote source.

According to another aspect, the switch is configured to receive a control signal transmitted remotely over an electric line to the electric lamp. According to another aspect, the first light source is a compact fluorescent lamp coated with a filter that blocks blue light that causes melatonin suppression in combination with blue LEDs in such number as to produce white light when combined with the light from the compact fluorescent lamp.

According to another aspect, the second light source is obtained by turning off the blue LEDs.

According to another aspect, the first light source includes a plurality of red, amber, green, and blue LEDs and in which the second source is produced by extinguishing the blue LEDs and selectively energizing the red, amber and green LEDs to produce light having the visual appearance of white light. According to another aspect, the effect of a second light source is provided by mechanically covering the first light source with a filter that blocks blue light having a wavelength shorter than about 530 nanometers.

According to another aspect, the filter is actuated manually or by electromechanical actuation.

According to another aspect, the second light source includes a plurality of LEDs mounted to a printed circuit board assembly (PCBA).

According to another aspect, the plurality of LEDs are configured to produce red light and green light having a wavelength of greater than about 530 nanometers that, when mixed, provide light output having substantially the same visual appearance as white light.

According to another aspect, the PCBA is configured as a heat sink.

According to another aspect, the PCBA is coupled to a threaded electrical connector. Another aspect of the disclosed technology relates to a light source for use in connection with an electric lamp. The light source includes a plurality of light emitting diodes (LEDs) configured to cooperate to produce light in a wavelength range that does not include a portion of the wavelength spectrum most effective in suppressing the production of melatonin; and a light-mixing optical element configured to mix light from the LEDs.

According to another aspect, the plurality of LEDs are configured to produce red light and green light having a wavelength of greater than about 530 nanometers that, when mixed, provide light output having substantially the same visual appearance as white light. According to another aspect, the light-mixing optical element includes a substantially transparent cylinder optically coupled to the plurality of LEDs and configured to mix light from the plurality of LEDs.

According to another aspect, the plurality of LEDs are arranged on a printed circuit board in a substantially circular configuration having a first diameter, and the diameter of the substantially transparent cylinder is approximately the same as the first diameter.

According to another aspect, the plurality of LEDs are arranged on a printed circuit board in a substantially circular configuration having a first diameter, and an inner diameter of the substantially transparent cylinder larger than the first diameter. According to another aspect, the substantially transparent cylinder includes a plurality of cylindrical lenses configured to mix light from the plurality of LEDs.

According to another aspect, the light-mixing element includes a plurality of substantially transparent cylinders optically coupled to the plurality of LEDs, wherein each LED includes a substantially transparent cylinder optically coupled to the respective LEDs.

According to another aspect, the light-mixing element includes a hemispherical optical element positioned above the LEDs and configured to mix light from the plurality of LEDs. According to another aspect, the light-mixing element includes a spherical optical element positioned above the LEDs and configured to mix light from the plurality of LEDs.

Another aspect of the disclosed technology relates to a light source for use in connection with an electric lamp, where the light source includes a plurality of light emitting diodes (LEDs); and a movable filter that is configured to selectively filter light emitted by the LEDs to filter out light in a wavelength range including a portion of the wavelength spectrum most effective in suppressing the production of melatonin.

According to another aspect, the filter is configured to selectively filter out light having a wavelength of less that about 530 nanometers.

According to another aspect, each LED is optically coupled to a lens configured to collimate light from each LED into a beam of a predetermined angle.

According to another aspect, the LEDs are arranged in a substantially circular configuration, and the movable filter includes a filter wheel that defines a plurality of openings, wherein the filter wheel is movable between a first position in which the openings are disposed over the LEDs and a second position in which the openings are not disposed over the LEDs, wherein light from the LEDs is filtered when the filter wheel is in the second position.

According to another aspect, the LEDs are selectively energized depending on the position of the filter.

According to another aspect, the drive current for the LEDs is increased when the filter is in the second position.

These and further features of the present invention will be apparent with reference to the following description and attached drawings. In the description and drawings, particular embodiments of the invention have been disclosed in detail as being indicative of some of the ways in which the principles of the invention may be employed, but it is understood that the invention is not limited correspondingly in scope. Rather, the invention includes all changes, modifications and equivalents coming within the spirit and terms of the claims appended thereto.

Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.

It should be emphasized that the term "comprises/comprising" when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

BRIEF DESCRIPTION OF DRAWINGS Many aspects of the invention can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present invention. Likewise, elements and features depicted in one drawing may be combined with elements and features depicted in additional drawings. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

FIG. 1 is a diagrammatic illustration of an electric lamp in accordance with one exemplary embodiment;

FIG. 2 is a diagrammatic illustration of an electric lamp in accordance with another exemplary embodiment;

FIG. 3 is a diagrammatic illustration of an electric lamp in accordance with another exemplary embodiment;

FIG. 4 is a diagrammatic illustration of an electric lamp in accordance with another exemplary embodiment; FIG. 5 is a diagrammatic illustration of an electric lamp in accordance with another exemplary embodiment;

FIG. 6A is a diagrammatic illustration of an exemplary light emitting diode (LED) for use in connection with the electric lamp; FIG. 6B is a diagrammatic illustration of another exemplary LED for use in connection with the electric lamp;

FIG. 7 is a diagrammatic illustration of an exemplary lighting assembly including a plurality of LEDs mounted on a printed circuit board (PCB); FIG. 8 is diagrammatic illustration of the exemplary assembly of FIG. 7 coupled to a threaded lamp connector;

FIG. 9 is a diagrammatic illustration of the exemplary assembly of FIG. 7 together with a first exemplary light-mixing cylinder;

FIG. 10 is a top view of the assembly of FIG. 9; FIG. 11 is a diagrammatic illustration of the exemplary assembly of FIG. 7 together with a second exemplary cylinder;

FIG. 12 is a top view of the assembly of FIG. 11;

FIG. 13 is a diagrammatic illustration of the exemplary assembly of FIG. 7 together with a plurality of cylindrical rods; FIG. 14 is a top view of the assembly of FIG. 13;

FIG. 15 is a diagrammatic illustration of the exemplary assembly of FIG. 7 together with a third exemplary cylinder including a plurality of cylindrical lenses;

FIG. 16 is a diagrammatic illustration of the exemplary assembly of FIG. 7 together with an exemplary hemispherical element; FIG. 17 is a top view of a portion of a light source in accordance with another exemplary embodiment;

FIG. 18 is a side view of FIG. 17;

FIG. 19 is a top view of FIG. 17 including a plurality of exemplary lenses;

FIG. 20 is a side view of FIG. 19; FIG. 21 is a top view of FIG. 19 including a movable filter in a first position;

FIG. 22 is a side view of FIG. 21;

FIG. 23 is a diagrammatic illustration of the light source of FIG. 21 incorporated into a socket-type lamp assembly;

FIG. 24 is a top view of FIG. 21 with the filter in a second position; FIG. 25 is a top view of a light source in accordance with another exemplary embodiment; and

FIG. 26 is a diagrammatic illustration of the light source of FIG. 25 incorporated into a socket-type lamp assembly. DETAILED DESCRIPTION OF EMBODIMENTS

In the detailed description that follows, like components have been given the same reference numerals regardless of whether they are shown in different embodiments of the present invention. To illustrate the present invention in a clear and concise manner, the drawings may not necessarily be to scale and certain features may be shown in somewhat schematic form.

It has been discovered that ordinary lights can be damaging to health because they produce the blue rays that have been found to cause melatonin suppression, especially if used during the evening preceding normal bedtime, when melatonin would be present. Melatonin is a hormone that promotes sleep, as well as being a powerful cancer fighter.

Some conventional light sources have been configured with filters to block blue light from an otherwise conventional light source, e.g., from a white-light- producing incandescent lamp. One problem discovered with respect to this technique is that the light sources appear yellow or amber, which may be undesirable and not pleasing to the eye. Also, the use of incandescent lamps requires considerable power and generates considerable heat.

The present disclosure recognizes shortcomings with conventional illumination sources, and provides an electric lamp that is configured to selectively switch between a first light source that produces white light and a second light source that produces light that appears to be substantially white light, but does not include portions of the wavelength spectrum that are most effective in suppressing the production of melatonin. In a preferred embodiment, at least a portion of the lamp includes light emitting diodes (LEDs) that are configured to emit green light and red light such that the resultant emitted light appears to be substantially white light.

Referring initially to FIGS. 1-5, an electric lamp 10 is provided. As is described in more detail below, the electric lamp 10 is configured to produce white light, e.g., from a first light source, and light that has substantially the same visual appearance as white light, e.g., from a second light source, where the light from the second light source does not include portions of the wavelength spectrum that are most effective in suppressing the production of melatonin.

As shown in FIG. 1, the electric lamp includes a first light source 12 and a second light source 14 that are coupled to circuitry (indicated generally by reference numeral 16) that is configured to selectively energize the first light source 12 and/or the second light source 14, for example, depending on the time of day. In one preferred embodiment (shown in FIG. 2), the electric lamp 10 includes a source of white light 12 and a source of non-blue light 14, e.g., light that has substantially the same visual appearance as white light, but does not include portions of the wavelength spectrum most effective in suppressing the production of melatonin (e.g., light that does not include blue light). In the exemplary embodiment illustrated in FIGS. 1-5, the circuitry 16 includes a switch 18, whereby the first and second light sources are coupled to a power supply 20 through the switch 18.

FIG. 3 shows another embodiment in which the circuitry 16 includes a controller 22 that is operatively coupled to the switch 18 and configured to actuate the switch 18 based on one or more predetermined criteria. For example, the controller 22 may include or be coupled to a timer 24 (FIG. 4), such as a timer associated with an alarm clock or other computer control, such that the controller may actuate the switch 18 to selectively energize the second light source and selectively de-energize the first light source depending on the time of day or depending on some other user- defined criteria.

It will be appreciated that the switch and control circuitry may take on a number of configurations without departing from the scope of the present invention. For example, the switch may be a simple mechanical switch or electromechanical switch that may be actuated manually by a user. Alternatively, as shown in FIG. 5, the switch 18 may be a radio frequency (RF) switch or an infrared switch that is configured to communicate wirelessly with a cooperative radio frequency controller, e.g., a controller associated with a remote control or a computer control. For example, an alarm clock may include a radio frequency transmitter or transmitter/receiver that is configured to transmit a command signal wirelessly to the RF switch at a predetermined time of day, e.g., at a predetermined time before the user's normal bedtime. Alternatively, the switch may receive command signals via an electric line coupled to the electric lamp.

As is described below, the first light source, e.g., a source of white light, and the second light source, e.g., a non-blue light source, may be selectively energized, thereby providing an electric lamp that provides normal white light during the day and light that has the appearance or substantially the same appearance as white light during the evening hours without providing the portion of the wavelength spectrum that is most effective in suppressing the production of melatonin. As is described more fully below, the first light source and the second light source may be embodied as a variety of different lamps or lamps with cooperative mechanical assemblies without departing from the scope of the present invention.

For example, the first light source may be a simple incandescent lamp that is configured to produce white light, and the second light source may be a second incandescent lamp in cooperation with a filter configured to block blue light. Alternatively, the second light source may include a simple incandescent lamp with an appropriate coating that is effective to block blue light. As a further alternative, the first light source may be a simple incandescent lamp with an appropriate coating that is effective to block blue light in combination with blue-light-producing LEDs. The second light source would then be effectuated by selectively de-energizing the blue light LEDs. However, as is described more fully below, preferred embodiments of the present invention include first and/or second light sources that are made up of light emitting diodes (LEDs) in a number of different configurations. Turning now to FIG. 6A and 6B, exemplary LED assemblies 30 are provided.

In one embodiment, the LED assembly 30 includes a semiconductor source of short or very short wavelength radiation, such as a LED chip 32, coupled to a pair of leads 34. The leads 34 may comprise in wires supported by a thicker lead frame or the leads may comprise self-supported electrodes, and the lead frame may be omitted. The leads 34 serve to provide current to the LED chip 32 causing the LED chip to emit radiation of a predetermined wavelength or range of wavelengths depending on the particular semiconductor LED chip being used. The LED assembly further includes a phosphor element or composition 36 that is optically or radiationally coupled to the LED chip 32. FIGS. 6A and 6B show two exemplary geometries for the phosphor element

36. For example, as shown in FIG. 6A, the phosphor element may include a hemispherical dome that is over or substantially on top of the LED chip 32. Alternatively, the phosphor element 36 may take on a different geometry, such as the one shown in FIG. 6B. The phosphor element may be configured and positioned to receive all of the optical radiation from the LED chip, or it may be configured to pass some of the optical radiation, while receiving or absorbing the remainder of the optical radiation. It will be appreciated that other configurations of semiconductor and cooperative phosphor elements may be provided without departing from the scope of the present invention. In a preferred embodiment, the second light source may include a number of LED assemblies 30 including a semiconductor chip configured to produce short wavelength light, e.g., light having a wavelength within the range of about 370 nanometers to about 450 nanometers or 500 nanometers, or very short wavelength light such as ultraviolet (UV) light or other blue light. Further, the phosphor element may be configured such that it emits red and green light, e.g., light having a wavelength of at least about 530 nanometers, in response to receiving short wavelength or very short wavelength light from the LED chip. It will be appreciated that other combinations of semiconductor LED chips and phosphor elements may be provided depending on the color or temperature of white light that is desired. Further, it will be appreciated that such LED assemblies may also be used to form some or the entire first light source, e.g., the light source configured to emit white light. This may be achieved by a suitable LED chip and phosphor configuration such that some of the short wavelength light may be emitted by the LED assembly and complimented by longer wavelength light emitted by the phosphor element upon receiving some short wavelength radiation from the LED chip. As will be appreciated, the LED chip 32 may be encapsulated within a shell, which encloses the LED chip, and an encapsulant material. The shell may be, for example, plastic or glass. The encapsulant may be an epoxy, plastic, low-temperature glass, polymer, resin or other type of known encapsulating material.

Alternatively, the second light source may be comprised of a plurality of LED assemblies, where some of the LED assemblies are configured to emit red light and the remainder of the of LED assemblies are configured to emit green light, such that the mix of the red light and green light is selected so that the resultant light emitted by the second light source has the appearance or substantially the same appearance as a source of white light. Preferably, the second light source is configured to produce light that does not include portions of the wavelength spectrum most effective in suppressing the production of melatonin, e.g., portions of the wavelength spectrum having a wavelength of less than about 530 nanometers. Turning now to FIGS. 7-16, a plurality of different lighting assembly configurations (also referred to simply as light sources) are provided. It will be appreciated that the various lighting assembly configurations described below may be incorporated into the second light source and/or the first light source. Further, the LEDs shown in the various exemplary embodiments, may include LEDs of the type shown in FIGS. 6 A and/or 6B or other types of LED assemblies that are configured to produce white light or configured to produce light that has the appearance of white light without including the portions of the wavelength spectrum that are effective in suppressing the production of melatonin. Turning now to FIG. 7, an exemplary LED array 40 is shown. The LED array

40 includes a plurality of LEDs 30 (for example, the types of LEDs shown in FIGS. 6A and/or 6B or other LED assemblies) mounted or otherwise electrically coupled to a printed circuit board assembly (PCBA) 42. In this exemplary embodiment, the LEDs 30 are arranged in a circular or substantially circular pattern on the PCBA 42. In this embodiment, the PCBA may also serve as a heat sink alone or together with other heat sink cooling elements, e.g., elements disposed adjacent area 46 on the PCBA 42, to help regulate the temperatures of the various LEDs during operation. The PCBA may include or otherwise be operatively coupled to suitable LED driver circuitry to selectively energize the various LEDs. FIG. 8 provides an exemplary embodiment of the LED array 40 mounted on a suitable connector element 44, such as an Edison-type threaded connector, whereby various heat sinks or other cooling mechanisms, as well as driver circuitry, may be housed within the connector 44. Of course, other geometries may be employed without departing from the scope of the present invention. Thermally connecting the LEDs to the printed circuit board assembly 42 and the connector allows for a thermal path to the base of the lamp, and in turn, to the socket, allowing the heat to flow away from the LEDs. This leaves the LEDs all concentrated and pointed away from the printed circuit board assembly.

As is described below, the LED array 40 may be incorporated with various optical assemblies to capture the light from the LEDs and redistribute to make it look like an ordinary incandescent lamp.

Turning now to FIGS. 9 and 10, one exemplary embodiment is provided in which the lighting assembly includes a transparent or substantially transparent cylinder 50 in optical communication with the plurality of LEDs 30. The cylinder 50 can be made of any suitable material, for example, a suitable transparent or substantially transparent acrylic or glass. In one embodiment, the edge of the cylinder 50 is polished and positioned to rest on the LEDs that have been arranged in a substantially circular configuration with the diameter such that the center of the wall of the cylinder rests on the centers of the respective LEDs. In this configuration, light that strikes the end of the cylinder at an angle to the normal of less than about eighty degrees will be totally internally reflected from the wall and travel away from the end. This is true if the index of refraction of the cylinder material is about 1.5. Of course other geometries may be employed to achieve the desired effect. Further, if the inside of the cylinder 50 is coated with a suitable diffuse white, highly-reflecting material that is an optical contact with the surface, the light will be redirected so that much of it will escape outward from the cylinder. It will be appreciated that the other end of the cylinder also may be covered with a diffuse white reflector that will improve uniformity of the light coming from the sides of the cylinder. Alternatively, it may be left clear to increase light intensity in the direction away from the base of the lamp. Another option is to modify the and slightly to reflect some light and transmit the balance.

Turning now to FIGS. 11 and 12, another exemplary embodiment of the lamp assembly includes LEDs 30 mounted in a circle or substantially in a circle on the PCBA/heat sink 42. The cylinder 54 is chosen to have an internal diameter that is slightly larger than the outer diameter defined by the circle of LEDs. In this embodiment, the wall of the cylinder 54 may include a diffusing material that has a high transmission so most of the light exits the cylinder. The portion reflected may be allowed to travel away from the base of the lamp or a diffuser/reflector may close that end and redirect the light to produce the desired appearance of an ordinary incandescent lamp.

FIG. 13 and FIG. 14 illustrate another exemplary embodiment in which the LEDs 30 are disposed in a circular pattern or substantially circular pattern including a plurality of transparent cylindrical rods 60. In this exemplary embodiment, each rod 60 includes a diameter slightly larger than the diameter of the individual LEDs 30, such that the rods 60 rest on the LEDs. The LEDs 30 are arranged in a circular pattern on the PCBA 42 (which also serves as a heat sink) and the cylindrical rods 60 are arranged in a circular pattern on top of the LEDs. In one embodiment, a stripe or stripes may be painted so as to be an optical contact with the surface of each rod on the inside of the circle so as to project the light by way of a cylindrical lensing action of the outer surface of the rod. It will be appreciated that by varying the width of the stripe, the amount of light at different distances along the length of the rod may be adjusted. This makes it possible to more nearly simulate the light from an ordinary incandescent lamp. The treatment of the end of the rod away from the LEDs may be varied as described above.

Turning now to FIG. 15, another embodiment of the lamp assembly is provided. This embodiment may be viewed as a combination of the two above- described embodiments in that it includes a generally cylindrical form 70 so that it may be extruded or otherwise formed from a transparent material, e.g., like acrylic, but also includes a plurality of cylindrical lenses 72 formed on both the inner and outer surfaces of the cylindrical element 70 so that when stripes are painted or otherwise produced in optical contact with the inside surface of the cylinder, light is projected outward in combination with the outer lenses.

FIG. 16 shows another exemplary embodiment in which a hemispherical optical element is supported above the ring of LEDs to direct light outwardly. A diffusing hemisphere may help mix the light to give the appearance more like an ordinary incandescent light bulb. The diameter of the hemisphere 80 may be slightly greater than the outside diameter of the ring of LEDs. While FIG. 16 illustrates a hemispherical element 80 above the ring of LEDs, it will be appreciated that a spherical element may also be employed without departing from the scope of the present invention.

Turning now to FIGS. 17-26, additional exemplary embodiments of a light source 40 are provided. FIGS. 17 and 18 show a plurality of LEDs 30, e.g., white

Luxeon™ Star LEDs, disposed in a generally circular arrangement on or above a heat sink plate 90, e.g., an aluminum heat sink plate. It will be appreciated that other plate and/or heat sink configurations and materials may be included without departing from the scope of the present invention. For example, the heat sink plate 90 may be used in conjunction with a printed circuit board assembly, or a printed circuit board assembly may be used instead of an aluminum heat sink plate.

In accordance with one embodiment, provided in FIGS. 19 and 20, each LED 30 includes light-mixing or light- focusing optics 92. For example, in the embodiment provided in FIGS. 19 and 20, each LED 30 is optically coupled to a lens 92 configured to collimate the light from each LED into a 25 -degree beam. Suitable lenses include, for example, Polymer Optics brand lenses. It will be appreciated that other lens geometries may be employed without departing from the scope of the present invention. In FIGS. 21-24, the light source 40 is shown including a movable filter 94, e.g., a filter wheel configured to selectively block light of predetermined wavelengths, such as the portion of the wavelength spectrum most effective in suppressing the production of melatonin. As is discussed above, this portion of the wavelength spectrum may include blue light and other light having a wavelength of less than about 530 nanometers. In one embodiment, the filter wheel 94 is rotatably mounted, through a center portion of the heat sink plate 90, to a motor 96 or other electromechanical device suitable for selectively rotating the filter wheel. The filter wheel may take on a number of geometries. For example, as shown in FIG. 21, the filter wheel may include or otherwise define a plurality of openings 100 such that the filter wheel may be rotated into a first position, in which light from the LEDs 30 is not filtered by the filter wheel 94, and rotated into a second position (FIG. 24) in which light from the LEDs is filtered by the filter wheel 94. In this configuration, the filter wheel may remain in the first position (FIG. 21) during daylight hours and be rotated into the second position in the evening hours to block wavelengths of light that are most effective in suppressing the production of melatonin. FIG. 23 shows how the light source may be incorporated into a socket-type housing, such as a PAR30 size package, so that the light source may be used in a conventional lamp socket. Of course, other housing geometries may be employed. Also, the motor may be operative Iy coupled to a receiver, e.g., a wireless receiver, and motor controller such that control signals for moving the filter may be received from a remote control, or through the lamp power supply.

When the filter wheel is in a position to filter light from the LEDs, e.g., in the second position shown in FIG. 24, the overall intensity of light emitted by the LEDs may be reduced due to the filtering provided by the filter wheel. In this case, the light source may be configured to selectively increase the intensity of the light from the LEDs when the filter wheel is positioned to filter light from the LEDs. For example, the LED drive current may be varied such that the LED drive current is increased when using the filter and decreased when not using the filter. Alternatively, as shown in FIGS. 25 and 26, the light source may include additional LEDs, e.g., additional LEDs near the center of the heat sink, where the additional LEDs are selectively energized, e.g., only energized when the filter is being used.

It will be appreciated that the various exemplary geometries shown in FIGS. 7-26 are shown for purposes of explanation, and aspects of the disclosed technology are not meant to be limited to only these exemplary embodiments. It will be further appreciated that other exemplary embodiments may be provided to illustrate the principle of capturing light from the LEDs and redistributing the captured light to make it look more like an ordinary incandescent lamp. Further, because the insides of the various devices are empty, they provide room for the electronic LED drivers necessary to power the lamp. The lamp assembly may also include suitable means to provide air circulation to cool the heat sinks for the LEDs and electronics. Further, the electronics may also include a receiver for a radio frequency control of the lamp and a coding that may be changed to control lamps either as a group or individually. In addition to using the above-described configurations for ordinary white or colored LEDs, these configurations may have other applications in that they mix light from individual LEDs so that the light coming out is a result of the mixing. This may be of special value in developing a special light source that appears to be producing white light, but is free of the blue light that has been shown to suppress melatonin. If one were to simply use a filter to absorb the blue light, the remaining light often appears yellow or orange. Because the eyes accommodate to light of different colors, this may not be a serious problem for some people. However, by removing both the blue light and its complimentary color, yellow, the remaining red and green light combines to produce a reasonably white appearing light. It will be appreciated that when using a ring of LEDs with the cylinder resting on top, red and green LEDs may be in alternate positions around the ring. In some cases, there may be two green LEDs for each red one. In the case of the embodiment using rods, the LEDs should be placed closely together so their light mixes within the rods. In some cases, the final mixing of the red and green light may be in a diffusing surface that surrounds the device.

The provision of an electric lamp having a first light source and a second light source in which the first light source includes white light, for example, provided by normal white LEDs (that produce all colors of light), and the second light source includes LEDs that produce light that appears to be light without providing the wavelengths that are known to suppress melatonin (especially a few hours before bedtime) results in a lamp that includes white light during the day and beneficial white-appearing, blue-free light in the evening. As is described above, the switch from one light source to the other light source may be done automatically, manually, or by means of a remote control that communicates with the circuit wirelessly with a radio frequency signal or through the house wiring.

As will be appreciated by one of skill in the art, computer program elements and/or circuitry elements of the invention may be embodied in hardware and/or in software (including firmware, resident software, micro-code, etc.). The invention may take the form of a computer program product, which can be embodied by a computer- usable or computer-readable storage medium having computer-usable or computer- readable program instructions, "code" or a "computer program" embodied in the medium for use by or in connection with the instruction execution system. In the context of this document, a computer-usable or computer-readable medium may be any medium that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. The computer-usable or computer-readable medium may be, for example but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, device, or propagation medium such as the Internet. Note that the computer-usable or computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, via, for instance, optical scanning of the paper or other medium, then compiled, interpreted, or otherwise processed in a suitable manner. The computer program product and any software and hardware described herein form the various means for carrying out the functions of the invention in the example embodiments.

Specific embodiments of an invention are disclosed herein. One of ordinary skill in the art will readily recognize that the invention may have other applications in other environments. In fact, many embodiments and implementations are possible. The following claims are in no way intended to limit the scope of the present invention to the specific embodiments described above. In addition, any recitation of "means for" is intended to evoke a means-plus-function reading of an element and a claim, whereas, any elements that do not specifically use the recitation "means for", are not intended to be read as means-plus-function elements, even if the claim otherwise includes the word "means."

Although the invention has been shown and described with respect to a certain preferred embodiment or embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In particular regard to the various functions performed by the above described elements (components, assemblies, devices, compositions, etc.), the terms (including a reference to a "means") used to describe such elements are intended to correspond, unless otherwise indicated, to any element which performs the specified function of the described element (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary embodiment or embodiments of the invention. In addition, while a particular feature of the invention may have been described above with respect to only one or more of several illustrated embodiments, such feature may be combined with one or more other features of the other embodiments, as may be desired and advantageous for any given or particular application.

Claims

1. An electric lamp comprising: a first light source configured to produce white light; a second light source configured to produce light in a wavelength range that does not include a portion of the wavelength spectrum most effective in suppressing the production of melatonin; and circuitry configured to selectively energize the first light source and/or the second light source.

2. The electric lamp of claim 1, wherein the circuitry is configured to selectively energize the first light source or the second light source the depending on the time of day.

3. The electric lamp of claim 1, wherein the second light source is configured to produce light that visually appears to be substantially white, but does not include a portion of the wavelength spectrum most effective in suppressing the production of melatonin.

4. The electric lamp of claim 1, wherein the second light source is configured to produce light having wavelengths longer than about 530 nanometers.

5. The electric lamp of claim 1, wherein the first light source comprises a light emitting diode (LED) chip that produces short wavelength visible light and a phosphor positioned to receive at least a portion of the short wavelength light from the LED chip, wherein the phosphor is configured to emit light in the balance of the visual spectrum upon receiving the short wavelength light.

6. The electric lamp of claim 1, wherein the first light source comprises a light emitting diode (LED) chip that produces light having a wavelength of about 370 nanometers to about 500 nanometers and a phosphor positioned to receive at least a portion of the light from the LED chip, wherein the phosphor is configured to emit light having wavelengths greater than about 530 nanometers.

7. The electric lamp of claim 1, wherein the second light source comprises a LED chip that produces ultraviolet (UV) or very short wavelength light and a phosphor positioned to receive the UV or very short wavelength light from the LED chip, wherein the phosphor is configured to emit light at wavelengths longer than about 530 nanometers.

8. The electric lamp of claim 5, wherein the second source is the same source as the first source in combination with a movable filter that blocks blue light having wavelengths shorter than about 530 nanometers.

9. The electric lamp of claim 1, wherein the circuitry includes a switch electrically coupled to the first light source and the second light source.

10. The electric lamp of claim 9, wherein the switch is a manual switch configured to be manipulated by a user.

11. The electric lamp of claim 9, wherein the circuitry includes a controller configured to actuate the switch.

12. The electric lamp of claim 9, wherein the circuitry includes a timer coupled to the switch, wherein the timer is configured to actuate the switch.

13. The electric lamp of claim 9, wherein the circuitry includes a radio frequency (RF) switch operable to receive a RF actuation signal from a remote source or an infrared switch operable to receive an infrared actuation signal from a remote source.

14. The electric lamp of claim 9, wherein the switch is configured to receive a control signal transmitted remotely over an electric line to the electric lamp.

15. The electric lamp of claim 1, wherein the first light source is a compact fluorescent lamp coated with a filter that blocks blue light that causes melatonin suppression in combination with blue LEDs in such number as to produce white light when combined with the light from the compact fluorescent lamp.

16. The electric lamp of claim 15, wherein the second light source is obtained by turning off the blue LEDs.

17. The electric lamp of claim 1, wherein the first light source includes a plurality of red, amber, green, and blue LEDs and in which the second source is produced by extinguishing the blue LEDs and selectively energizing the red, amber and green LEDs to produce light having the visual appearance of white light.

18. The electric lamp of claim 5, wherein the effect of a second light source is provided by mechanically covering the first light source with a filter that blocks blue light having a wavelength shorter than about 530 nanometers.

19. The electric lamp of claim 18, wherein the filter is actuated manually or by electromechanical actuation.

20. The electric lamp of claim 1, wherein the second light source includes a plurality of LEDs mounted to a printed circuit board assembly (PCBA).

21. The electric lamp of claim 20, wherein the plurality of LEDs are configured to produce red light and green light having a wavelength of greater than about 530 nanometers that, when mixed, provide light output having substantially the same visual appearance as white light.

22. The electric lamp of claim 20, wherein the PCBA is configured as a heat sink.

23. The electric lamp of claim 20, wherein the PCBA is coupled to a threaded electrical connector.

24. A light source for use in connection with an electric lamp, the light source comprising: a plurality of light emitting diodes (LEDs) configured to cooperate to produce light in a wavelength range that does not include a portion of the wavelength spectrum most effective in suppressing the production of melatonin; and a light-mixing optical element configured to mix light from the LEDs.

25. The light source of claim 24, wherein the plurality of LEDs are configured to produce red light and green light having a wavelength of greater than about 530 nanometers that, when mixed, provide light output having substantially the same visual appearance as white light.

26. The light source of claim 25, wherein the light-mixing optical element includes a substantially transparent cylinder optically coupled to the plurality of LEDs and configured to mix light from the plurality of LEDs.

27. The light source of claim 26, wherein the plurality of LEDs are arranged on a printed circuit board in a substantially circular configuration having a first diameter, and the diameter of the substantially transparent cylinder is approximately the same as the first diameter.

28. The light source of claim 26, wherein the plurality of LEDs are arranged on a printed circuit board in a substantially circular configuration having a first diameter, and an inner diameter of the substantially transparent cylinder larger than the first diameter.

29. The light source of claim 26, wherein the substantially transparent cylinder includes a plurality of cylindrical lenses configured to mix light from the plurality of LEDs.

30. The light source of claim 25, wherein the light-mixing element includes a plurality of substantially transparent cylinders optically coupled to the plurality of LEDs, wherein each LED includes a substantially transparent cylinder optically coupled to the respective LEDs.

31. The light source of claim 25, wherein the light-mixing element includes a hemispherical optical element positioned above the LEDs and configured to mix light from the plurality of LEDs.

32. The light source of claim 25, wherein the light-mixing element includes a spherical optical element positioned above the LEDs and configured to mix light from the plurality of LEDs.

33. A light source for use in connection with an electric lamp, the light source comprising: a plurality of light emitting diodes (LEDs); and a movable filter that is configured to selectively filter light emitted by the LEDs to filter out light in a wavelength range including a portion of the wavelength spectrum most effective in suppressing the production of melatonin.

34. The light source of claim 33, wherein the filter is configured to selectively filter out light having a wavelength of less that about 530 nanometers.

35. The light source of claim 33, wherein each LED is optically coupled to a lens configured to collimate light from each LED into a beam of a predetermined angle.

36. The light source of claim 33, wherein the LEDs are arranged in a substantially circular configuration, and the movable filter includes a filter wheel that defines a plurality of openings, wherein the filter wheel is movable between a first position in which the openings are disposed over the LEDs and a second position in which the openings are not disposed over the LEDs, wherein light from the LEDs is filtered when the filter wheel is in the second position.

37. The light source of claim 36, wherein the LEDs are selectively energized depending on the position of the filter.

38. The light source of claim 37, wherein the drive current for the LEDs is increased when the filter is in the second position.