WO2010116200A1

WO2010116200A1 - Energy saving led lamp and tube

Info

Publication number: WO2010116200A1
Application number: PCT/IB2009/051447
Authority: WO
Inventors: Song Lee
Original assignee: Yipi Pte Ltd
Priority date: 2009-04-07
Filing date: 2009-04-07
Publication date: 2010-10-14

Abstract

The invention discloses LED lamps (10) and tubes that are energy saving. The LED lamp (10) comprises of lamp head (11 ), lamp casing (12), lamp cover (13), electrical control circuits (20), passive infrared sensor (16) with Fresnel lens (18) and light sensor (19). The passive infrared sensor (16) is used to detect the presence of human motion. The light sensor (19) points in the direction outside the viewing angle of the LEDs (14) so that it is not affected by the light from the LEDs (14) and is used to detect the surrounding brightness. The LED tube comprises of end caps, longitudinal tube, electrical control circuits, passive infrared sensor with Fresnel lens and light sensor. Based on the input from the sensors, the electrical control circuits in the LED lamps and tubes can control the LEDs to be fully on (full brightness), fully off (totally no light), or dimmed (some light). When no persons are around, the LED lamps and tubes can be dimmed or turned off. When the surrounding is bright, the LED lamps and tubes can be dimmed or turned off. In so doing, significant amount of energy can be saved.

Description

Description Title of Invention: ENERGY SAVING LED LAMP AND TUBE

Technical Field Technical Field

[1] The present invention relates to energy saving light emitting diode (LED) lamp and tube , more particularly, LED lamp and tube that consumes significantly less energy and has longer lifespan using passive infrared sensor and light sensor. Background Art Background Art

[2] LED lamps and tubes have been in existence for many years now and its merits over fluorescent or incandescent lighting are well know. One main advantage is that LEDs produce more lumens per watt compared to fluorescent or incandescent lighting. In other words, LED lamps and tubes use less energy than fluorescent or incandescent lighting to produce the same amount of light.

[3] In order to further save energy, motion sensors are used to detect the presence of humans. Traditionally, an external motion sensor is mounted in the area of interest and controls a group of lamps, which belong to the same electrical circuit. When motion is detected, all the lamps are turned on. When there is no one around, the motion sensor triggers a device which cuts off power to the lighting circuit, turning off all the lamps in the same group. Similar principle is applied when using photo sensors. An external photo sensor is mounted in the area of interest and controls a group of lamps, which belong to the same electrical circuit. The photo sensor provides signals to a device which can either provide or cut off power to the lighting circuit. Sometimes the lights belonging to the same electric circuit are in different physical locations and this method of control is not effective. For example, a lighting circuit controls the lights in the lift lobbies from the first floor to the tenth floor. The motion or photo sensor can be used to either turn on or off all the lights. If the motion sensor is installed on the first floor and detects the presence of someone on the first floor, the lights on the first floor and the other floors will be turned on. Further energy savings and finer control will require rewiring of the electrical circuits if external sensors are used.

[4] One method around this problem is to incorporate the motion sensor or photo sensor into each lamp. One such invention is disclosed in US Patent No. 6,820,998. Referring to FIG. 1, the LED lamp 1 comprises of a lamp head 2, a lamp casing 3, and a lamp cover 4. The LED lamp 1 further comprises LEDs 5, human body sensor 6 and a light sensor 7. The LEDs 5 and human body sensor 6 are mounted together and enclosed in a lamp casing 5 and lamp cover 6. The light sensor 7 is positioned on the side of the light casing 7. The human body sensor 6 and photo sensor 7 provide input signals to the circuit (not shown), which controls the lighting of the LEDs 5.

[5] Another invention is disclosed in US Patent No. 7,067,992. The invention discloses electrical circuit means of providing power to the LEDs. A computer within the LED tube controls the power switch or dimmer. Sensors, such as occupancy motion detection sensor, can provide signals to the computer to trigger the switch or control a dimmer.

Disclosure of Invention Technical Problem

[6] Lights are used everywhere and any inefficiency or ineffectiveness in the design of lights will result in a lot of extra energy consumption worldwide. As such, it is an object of this invention to provide efficient and effective energy saving LED lamp or tube.

[7] There are various types of human detection sensors, such as active ultrasonic sensors, active microwave sensors, active infrared sensors and passive infrared sensors. The active sensors continuously send out signals, such as sound waves, microwaves or infrared waves and measures the reflected signals to determine whether there is motion. The active sensors consume energy continuously and do not maximize the savings of energy. The passive infrared sensor is passive in nature, that is, it does not consume energy in order to detect motion.

[8] Referring to FIG 1, the lamp cover 4 is often made of glass or transparent plastics such as polycarbonate. The lamp cover 4 allows light from the LEDs 5 to go through, but does not allow or allows very little infrared radiation of the correct wavelength from the outside to pass through. If the human body sensor 6 is a passive infrared sensor, then the energy saving lamp 1 is ineffective as infrared radiation from the outside cannot pass through the lamp cover 4 and reach the passive infrared sensor 6. Furthermore, passive infrared sensors have low operating temperatures, such as 40 degree Celsius or below, while LEDs tend to generate heat, especially the high power LEDs, and the printed circuit board (PCB) on which the LED is mounted is often higher than 40 degree Celsius. This will make the passive infrared sensor fail or misbehave if it is mounted on the same PCB as the LEDs and when the temperature is more than 40 degree Celsius.

[9] Again referring to FIG 1, the photo sensor 7 is also ineffective. Starting from the situation where it is dark, the photo sensor 7 will feedback to the control circuit and turn on the LEDs 5. When the LEDs 5 are turned on, the LEDs will light up surfaces which will reflect the light from the LEDs back to the photo sensor 7. The photo sensor 7 will then feedback to the control circuit that the environment is bright. The LEDs 5 will be turned off. The cycle repeats and the LEDs 7 are turned on and off continuously, leading to inefficiency, shorter lifespan of the LED lamp or discomfort to users. Technical Solution

[10] For the passive infrared sensor to work effectively, it needs to be able to receive infrared radiation. The lamp cover directly over the passive infrared sensor will need to let infrared radiation through. One way is to have a hole there. This opening at the lamp cover will allow infrared radiation through to the passive infrared sensor. Furthermore, as the infrared sensor is passive (does not consume energy), its effective distance for sensing is very limited. To increase this distance, a focusing lens, such as a Fresnel lens, can be used to increase the amount of infrared radiation it receives. Of course, the Fresnel lens must be made of materials which allow infrared radiation to pass through. This can increase the effective distance in sensing human body motion from 0.3 meters to more than 5 meters.

[11] The passive infrared sensor is preferred to be mounted on a separate printed circuit board, so as to separate the heat from the LEDs from it. Thus even though the temperature of the PCB where the LEDs are mounted is above 40 degree Celsius, the passive infrared sensor can still be below 40 degree Celsius and operate normally.

[12] For the photo sensor to differentiate between day and night, the simplest solutions is to position the photo sensor such that it points in the direction opposite from the LEDs. So if the LEDs face forward, the photo sensor should face backwards. This will allow the photo sensor to receive significant light from the sun and not the LEDs. Thus even if the LEDs are turned on, the photo sensor will still be able to differentiate between day and night. The reason why this works is because light from the sun is strong and is reflected by many bodies and are in all directions whereas light from LEDs are directional. The photo sensor can also point in other directions, as long as the direction of the photo sensor is beyond the areas directly illuminated by the LEDs.

[13] The signals from the passive infrared sensor or light sensor are fed into an electrical control circuit which controls the brightness of the LEDs. The electrical control circuit can turn on, turn off or dim the LEDs. The electrical control circuit could include an LED driver, which takes in alternating current and provides the required direct current to the LEDs, a passive infrared sensor circuit which amplifies the signal from the passive infrared sensor. The electrical control circuit could further include electrical relays, transistors and MOSFETs which acts like switches and aids in the control of the amount of current going to the LEDs based on the signals from sensors. The electrical control circuit is well known in the art. Some simple electrical control circuits can be bought directly from suppliers, while special electrical control circuits can be custom made. Advantageous Effects

[14] This invention overcomes the disadvantages and limitations of prior art. This invention discloses effective and efficient energy saving LED lamp and tube. Energy savings by the LED lamps and tubes can be optimized and maximized at the individual lamp level, which is better in many situations compared to controlling the lamps as a group. In certain applications, such as night time corridor lighting, whereby there are no users most of the time, this invention can result in over 90 percent in energy savings compared to a lamp without effective sensors. Description of Drawings

[15] The accompanying drawings are solely for purposes of illustrating the concepts of the invention and are not drawn to scale. The embodiments shown in the accompany drawings, and described in the accompanying detailed description, are used as illustrative embodiments and should not be construed as the only manner of practicing the invention. Also, the same reference numerals, possibly supplemented with reference characters where appropriate, have been used to identify similar parts. These and other objects and features of this invention will be clear and apparent to those skilled in the art upon reading the detailed description together with the drawings, wherein:

[16] FIG. 1 shows a prior art of an energy saving LED lamp;

[17] FIG. 2 shows a part section view of an energy saving LED lamp with passive infrared sensor and light sensor;

[18] FIG. 3 shows various lamp heads for LED lamp;

[19] FIG. 4 shows a part section view of an energy saving LED tube with passive infrared sensor and light sensor;

[20] FIG. 5 shows a part section view of an energy saving LED lamp with passive infrared sensor mounted on extensible tube, and light sensor;

[21] FIG. 6 shows a part section view of another configuration of an energy saving LED lamp with passive infrared sensor mounted on extensible tube and light sensor. Best Mode

[22] Referring to FIG. 2, it shows an energy saving LED lamp 10 comprising of a lamp head 11, a lamp casing 12, and a lamp cover 13. The lamp head 11 is a typical screw type lamp head, such as type E27. The lamp casing 12 can be made of plastic, metal or glass. The lamp cover 13 is transparent or translucent and allows light to pass through. The lamp cover 13 can be made of glass or plastics, such as polycarbonate (PC) or poly(methyl methacrylate) (PMMA) . The lamp cover 13 can be smooth or have patterns to help diffuse the light and reduce glare.

[23] The LED lamp 10 further comprises plurality of LEDs 14, which are mounted on a printed circuit board (PCB) 15, electrical control circuit 20 and electrical wires or connections 21. The electrical control circuit 20 accepts alternating current power supply through the lamp head 11 via electrical connections 21, rectifies the alternating current to direct current and drives the LEDs 14 via electrical connections 22.

[24] The energy saving LED lamp 10 also has sensors like the passive infrared sensor 16 and light sensor 19. The passive infrared sensor 16 does not need power to operate, unlike active sensors which continuously consumes energy and sends out signals. The passive infrared sensor 16 will produce a pulse when there is human motion. Its range is very limited, such as 0.3 meters from the sensor, as it is passive in nature. A Fresnel lens 17 made of material which is transparent to infrared radiation, such as polyethylene, is added in front of the passive infrared sensor 16 to focus more infrared radiation on it. Often, the material that lets light through, such as glass, does not allow infrared radiation (or more specifically the infrared radiation that is in the body temperature range) through, and material that lets infrared radiation through is not good at letting light through. So, an opening in the LED cover 13 in front of the passive infrared sensor 16 is required. The Fresnel lens 18 covers the opening in the lamp cover 13. In so doing, the passive infrared sensor 16 is able to detect human body motion more than 5 meters away. The passive infrared sensor 16 is not able to operate well at high temperatures. It is best for the passive infrared sensor 16 to operate at below 40 degrees. LEDs generate lots of heat and the PCB 15 on which they are mounted gets heated up. Sometimes, the temperature can be more than 60 degrees. As such, the passive infrared sensor 16 is mounted on PCB 17, which is separate from PCB 15 where the LEDs 14 are mounted. While it is described here that the LEDs 14 and the passive infrared sensor 16 are mounted on PCBs 15 and 17 respectively, they can also be mounted on other boards or substrates and the term PCB is meant to also include any other boards or substrates.

[25] The light sensor 19 can be a light dependant resistor or other photo sensitive devices such as a photo transistor. For a light dependant resistor, its resistance will change base on the amount of light it receives. The purpose of the light sensor 19 is to detect the amount of ambient light, so as to determine whether the environment is bright (day) or dark (night). The positioning of the light sensor 19 is very important. The light sensor 19 should not be placed in the same or similar directions as the LEDs 14. Otherwise, the energy saving LED lamp 10 will not be able to operate effectively. This is because the light from the LED lamp 10 or neighboring lamps will significantly influence the amount of light reaching the light sensor 19. The light sensor 19 needs to be positioned generally pointing outside the area directly illuminated by the LEDs 14, or in other words, pointing outside the light cone of the LEDs 14. The further the light sensor 19 points away from the light cone of the LEDs 14 the better. And so it is preferable for the light sensor 19 to point in the opposite direction from the LEDs 14. This is so that the light sensor is influence by sunlight, which tends to generate significant reflected light in many directions, but the not light from the LEDs 14 or from neighbouring LED lamps, which tend to generate directional light.

[26] The passive infrared sensor 16 and light sensor 19 are connected to the electrical control circuit 20 via electrical connections 23 and 24 respectively. The electrical control circuit 20 can be designed to operate in various states according to whether there is human body motion or not, whether the environment is bright or dark, so as to maximize the savings of energy. For example, for open corridor lighting that operates non-stop, the energy saving LED lamp 10 can be off (no light) when the surrounding is bright (day). When the surrounding becomes dark (at night or at times when there is little sunlight like when it is raining), the energy saving LED lamp 10 is turned on but dimmed (some light). When people move near the LED lamp 10, it is fully on (full brightness). The electrical control circuit 20 can have a timer which keeps the LED lamp 10 fully on for a period of time, say 1 minute, after the people leave the vicinity of the LED lamp 10. This is to avoid the situation when the LED lamp 10 changes state from bright to dim when the people around the LED lamp 10 do not move for a short period of time. While an example of the state of lighting according to the state of the sensors is provided here, it is not the only possibility. It is obvious that other combinations of lighting states and sensor states are possible.

[27] The electrical control circuit 20 could include an LED driver, which takes in alternating current and provides the required direct current to the LEDs 14, a passive infrared sensor circuit which amplifies the signal from the passive infrared sensor. The electrical control circuit 20 could further include electrical relays, transistors and MOSFETs which acts like switches and aids in the control of the amount of current going to the LEDs based on the signals from sensors. The electrical control circuit 20 is well known in the art and is not described in very much details as it is obvious to those skilled in the art. Mode for Invention

[28] Other modes of invention exist. Depending on the need, various configurations using the concept above can be used.

[29] While the invention was described with a typical E27 screw type lamp head, it could be fitted with other types of lamp heads. Referring to FIG. 3, it shows different common types of lamp heads, such as an E14 screw type lamp head 30a, a BA22 lamp head 30b, a GuIO lamp head 30c, a G5.3 lamp head 3Od and a G24d lamp head 3Oe. Other lamp heads not shown here can also be used.

[30] The same applies to the lamp casing and lamp cover. Other shapes and material can be used for the invention, while keeping to the concepts of the invention. The principles of the invention can also be applied to energy saving LED tubes. Referring to FIG. 4, it shows a LED tube 50 comprising end caps 51 with electrical pins 52 and plastic tube 53. The front of the plastic tube 54 is transparent and allows light to pass through. Within the tube 53, there are LEDs 55 pointing downwards, which are mounted on PCB 56, electric control circuit 60, passive infrared sensor 62 and light sensor 65. There is a hole at the front of the plastic tube 54 where the passive infrared sensor 62, which is mounted on a PCB 63 separate from the LED PCB 56, is placed. In front of the passive infrared sensor 62, there is a Fresnel lens 64 which focuses infrared radiation to the passive infrared sensor 62. The light sensor 65 is placed at the back of the plastic tube 53. A hole or window is provided at the back of the plastic tube 53 if the back of the plastic tube is opaque to light, so that the light sensor 65 can receive light from the environment. Again, the position of the light sensor 65 is important. It is in the direction away from the direction of the LEDs 55 and outside the light cone of the LEDs 55. The passive infrared sensor 62 and light sensor 65 are connected to the electrical control circuit 60 via electrical connections 66 and 67 respectively.

[31] In certain cases, lamps or tubes are installed in lighting fixtures that have an additional cover over them. The additional cover might be a grating or a frosted flat piece and the purpose is to avoid glare from the light reaching users. In such a situation, the passive infrared sensor might not operate well as infrared radiation might not be able to reach it. To overcome this problem, the passive infrared sensor together with the Fresnel lens can be attached to the end of conduit, which allows the passive infrared sensor to extend beyond the surface of the lamp cover. Referring to FIG. 5, the energy saving LED lamp 10a, is similar to the LED lamp 10 described earlier, except that the passive infrared sensor 16, PCB 17 and Fresnel lens 18 are attached to the end of a conduit 25a, like an extensible tube 25a. The conduit 25a refers to any structure containing one or more ducts. The conduit 25a allows the passive infrared sensor 16 to be extended down to the additional cover 26 of the lighting fixture, while keeping the LED lamp or LED tube at the same place. Of course, the electrical connection 23a between the passive infrared sensor and the electrical control circuit 20 needs to be maintained and sufficient wire needs to be provided for this. Other modes are also possible. Referring to FIG. 6, the LED lamp 10b has the conduit or extensible tube 25b starting from the lamp casing 12b instead of the lamp cover 13b. The electrical connection 23b is made sufficient long. The same function is achieved and other configurations will be obvious to those skilled in the art.

[32] The same principle of having the passive infrared sensor attached to the end of a conduit can be applied to the energy saving LED tube to overcome the same problem. Also, instead of placing the infrared sensor at the plastic tube area, it could be placed at either of the end caps. The end caps can be made longer if required to accommodate the passive infrared senor, Fresnel lens or the conduit.The light sensor can also be placed at one of the end caps.

[33] While the present invention has been explained by reference to the preferred embodiments described above, it will be appreciated that the embodiments are only illustrated as examples to assist understanding of the present invention and are not meant to be restrictive on its scope. In particular, the scope, ambit and spirit of this invention are meant to include the general principles of the invention as inferred or exemplified by the embodiments described above. More particularly, variations or modifications which are obvious or trivial to persons skilled in the art, as well as improvements made on the basis of the present invention, should be considered as falling within the scope and boundary of the present invention.

[34] Furthermore, while the present invention has been explained by reference to energy saving LED lamp and LED tube, it should be appreciated that the invention can apply, whether with or without modifications, to other types LED lighting without loss of generality. Industrial Applicability

[35] This invention allows for the replacement of existing incandescent lamps, fluorescent lamps and tubes, and LED lamps and tubes with energy saving LED lamps and tubes. This will reduce energy consumption, especially at times when no one is around or when the environment is bright.

Claims

Claims[Claim 1] What is claimed is:

1. An energy saving LED lamp comprising: a lamp head, wherein said lamp head can connect to lamp socket; a lamp casing, wherein said lamp casing is attached to said lamp head; a lamp cover, wherein said lamp cover is attached to lamp casing and said lamp cover is transparent or translucent to light; a plurality of LEDs, wherein said LEDs are mounted on a first printed circuit board placed within said lamp; a passive infrared sensor; wherein said passive infrared sensor is not blocked by the said lamp cover, and is mounted on a second printed circuit board separate from said first printed circuit board; a Fresnel lens, wherein said Fresnel lens is made of material transparent to infrared radiation, and said Fresnel lens is positioned in front of said passive infrared sensor and focuses infrared radiation on said passive infrared sensor; an electrical control circuit, wherein said electrical control circuit is connected to power source via said lamp head and controls the brightness of the LEDs based on the signal of said passive infrared sensor.

[Claim 2] 2. The energy saving LED lamp of claim 1, further comprising of a conduit, wherein said conduit connects the said Fresnel lens and said passive infrared sensor to said lamp cover.

[Claim 3] 3. The energy saving LED lamp of claim 1, further comprising of a conduit, wherein said conduit connects said Fresnel lens and said passive infrared sensor to said lamp casing.

[Claim 4] 4. The energy saving LED lamp of claim 1, further comprising of a light sensor, wherein said light sensor is positioned such that said light sensor points in the opposite direction of said LEDs or in the direction outside of the light cone of said LEDs, wherein said light sensor is connected to said electrical control circuit and said electrical control circuit controls the brightness of the LEDs based on the signal of said light sensor.

[Claim 5] 5. An energy saving LED lamp comprising: a lamp head, wherein said lamp head can connect to lamp socket; a lamp casing, wherein said lamp casing is attached to said lamp head; a lamp cover, wherein said lamp cover is attached to lamp casing and said lamp cover is transparent or translucent to light; a plurality of LEDs, wherein said LEDs are mounted on a first printed circuit board placed within said lamp; a light sensor, wherein said light sensor is positioned such that said light sensor points in the direction opposite the direction of said LEDs or in the direction outside the light cone of said LEDs; an electrical control circuit, wherein said electrical control circuit is connected to power source via said lamp head and controls the brightness of the LEDs based on the signal of said light sensor.

[Claim 6] 6. An energy saving LED tube comprising: a first end cap, further comprising electrical pins; a second end cap, further comprising electrical pins; a longitudinal tube, wherein said tube has one end capped with said first end cap and another end capped with said second end cap, and said tube has at least one part transparent or translucent to light; a plurality of LEDs, wherein said LEDs are mounted on a first printed circuit board placed within said tube; a passive infrared sensor; wherein said passive infrared sensor is not blocked by the said longitudinal tube and said end caps, and is mounted on a second printed circuit board separate from said first printed circuit board; a Fresnel lens, wherein said Fresnel lens is made of material transparent to infrared radiation, and said Fresnel lens is positioned in front of said passive infrared sensor and focuses infrared radiation on said passive infrared sensor; an electrical control circuit, wherein said electrical control circuit is connected to power source via said electrical pins and controls the brightness of the LEDs based on the signal of said passive infrared sensor.

[Claim 7] 7. The energy saving LED tube of claim 6, further comprising of a conduit, wherein said conduit connects said Fresnel lens and said passive infrared sensor to said longitudinal tube.

[Claim 8] 8. The energy saving LED lamp of claim 6, further comprising of a conduit, wherein said conduit connects said Fresnel lens and said passive infrared sensor to either said first end cap or said second end cap.

[Claim 9] 9. The energy saving LED tube of claim 6, further comprising of a light sensor, wherein said light sensor is positioned such that said light sensor points in the opposite direction of said LEDs or in the direction outside of the light cone of said LEDs, wherein said light sensor is connected to said electrical control circuit and said electrical control circuit controls the brightness of the LEDs based on the signal of said light sensor.

[Claim 10] 10. An energy saving LED tube comprising: a first end cap, further comprising electrical pins; a second end cap, further comprising electrical pins; a longitudinal tube, wherein said tube has one end capped with said first end cap and another end capped with said second end cap, and said tube has at least a part that is transparent or translucent to light; a plurality of LEDs, wherein said LEDs are mounted on a first printed circuit board placed within said tube; a light sensor, wherein said light sensor is positioned such that said light sensor points in the direction opposite the direction of said LEDs or in the direction outside the light cone of said LEDs; an electrical control circuit, wherein said electrical control circuit is connected to power source via said electrical pins and controls the brightness of the LEDs based on the signal of said light sensor.