Patent Application
20160290598
The present invention relates to illumination device, and more particularly to an LED tube lamp with a reflective film layer disposed on an inner circumferential surface of a lamp tube thereof.
Today LED lighting technology is rapidly replacing traditional incandescent and fluorescent lights. Even in the tube lamp applications, instead of being filled with inert gas and mercury as found in fluorescent tube lamps, the LED tube lamps are mercury-free. Thus, it is no surprised that LED tube lamps are becoming highly desired illumination option among different available lighting systems used in homes and workplace, which used to be dominated by traditional lighting options such as compact fluorescent light bulbs (CFLs) and fluorescent tube lamps. Benefits of the LED tube lamps include improved durability and longevity, and far less energy consumption, therefore, when taking into of all factors, they would be considered as cost effective lighting option.
There are several types of LED tube lamps that are currently available on the market today. Many of the conventional LED tube lamp has a housing that use material such as an aluminum alloy combined with a plastic cover, or made of all-plastic tube construction. The lighting sources usually adopt multiple rows of assembled individual chip LEDs (single LED per chip) being welded on circuit boards, and the circuit boards are secured to the heat dissipating housing. Because this type of aluminum alloy housing is a conductive material, thus is prone to result in electrical shock accidents to users. In addition, the light transmittance of the plastic cover or the plastic tube diminish over time due to aging, thereby reducing the overall lighting or luminous efficiency of the conventional LED tube lamp. Furthermore, grainy visual appearance and other derived problems reduce the luminous efficiency, thereby reducing the overall effectiveness of the use of LED tube lamp. The LED light sources are typically a plurality of spatially arranged LED chips. With respect to each LED chip, due to its intrinsic illumination property, if there was no any sufficient further optical processing, the entire tube light will exhibit grainy or non-uniform illumination effect; as a result, grainy effect is produced to the viewer or user, thereby negatively affect visual aesthetics thereof. In other words, the overall illumination distribution uniformity of the light outputted by the LED light sources without having additional optical processing techniques or structures for modifying the illumination path and uniformity would not be sufficient enough to satisfy the quality and aesthetics requirements of average consumers.
Referring to US patent publication no. 2014226320, as an illustrative example of a conventional LED tube lamp, the two ends of the tube are not curved down to allow the end caps at the connecting region with the body of the lamp tube (including a lens, which typically is made of glass or clear plastic) requiring to have a transition region. During shipping or transport of the LED tube lamp, the shipping packaging support/bracket only makes direct contact with the end caps, thus rendering the end caps as being the only load/stress points, which can easily lead to breakage at the transition region with the glass lens.
With regards to the conventional technology directing to glass tube of the LED tube lamps, LED chip on board is mounted inside the glass-tubed tube lamp by means of adhesive. The end caps are made of a plastic material, and are also secured to the glass tube using adhesive, and at the same time the end cap is electrically connected to the power supply inside tube lamp and the LED chip on boards. This type of LED tube lamp assembly technique resolves the issue relating to electrical shocks caused by the housing and poor luminous transmittance issues. But this type of conventional tube lamp configured with the plastic end caps requires a tedious process for performing adhesive bonding attachment because the adhesive bonding process requires a significant amount of time to perform, leading to production bottleneck or difficulties. In addition, manual operation or labor are required to perform such adhesive bonding process, thus would be difficult for manufacturing optimization using automation. In addition, sometimes the end cap and the glass lamp tube may come apart from one another when the adhesive does not sufficiently bond the two, thus the detachment of the end cap and the glass lamp tube can be a problem yet to be solved.
In addition, the glass tube is a fragile breakable part, thus when the glass tube is partially broken in certain portion thereof, would possibly contact the internal LED chip on boards when illuminated, causing electrical shock incidents. Referring to Chinese patent publication no. 102518972, which discloses the connection structure of the lamp caps and the glass tube, as shown in FIG. 1 of the aforementioned Chinese patent reference, it can be seen that the lamp end cap protrudes outward at the joining location with the glass tube, which is commonly done in the conventional market place. According to conducted studies, during the shipping process of the LED tube lamps, the shipping packaging support/bracket only makes contact with the lamp end caps, which make the end caps as being the only load/stress points, which can easily lead to breakage at the transition coupling regions at the ends of the glass tube. In addition, with regards to the secure mounting method of the lamp end caps and the glass tube, regardless of whether using hot melt adhesive or silicone adhesive, it is hard to prevent the buildup and light blockage of excess (overflown) leftover adhesive residues, as well as having unpleasant aesthetic appearance thereof. In addition, large amount of manpower is required for cleaning off of the excessive adhesive buildup, creating further production bottleneck and inefficiency. As shown also from FIGS. 3 and 4 of the aforementioned Chinese patent application, the LED lighting elements and the power supply module require to be electrically connected via wire bonding technique, and can be a problem or issue during shipping due to the concern of breakage.
Based on the above, it can be appreciated that the LED tube lamp fabricated according to the conventional assembly and fabrication methods in mass production and shipping process can experience various quality issues and are in need of improvements to be made. Referring to US patent publication no. 20100103673, which discloses of an end cap substitute for sealing and inserting into the housing. However, based on various experimentation, upon exerting a force on the glass housing, breakages can easily occur, which lead to product defect and quality issues. Meanwhile, grainy visual appearances are also often found in the aforementioned conventional LED tube lamp.
To solve at least one of the above problems, the present invention provides an LED tube lamp having an LED light bar, in which the LED light bar is a bendable circuit sheet.
The present invention provides an LED tube lamp that includes a plurality of LED light sources, a LED light bar, a lamp tube, at least one end cap and at least one power supply.
The present invention provides the LED light bar to be disposed inside the lamp tube, the LED light sources are mounted on the LED light bar, the LED light sources and the power supply are electrically connected by the LED light bar.
In an embodiment of the present invention, two end caps are provided, in which each end cap is equipped with one power supply. The sizes of the two end caps are different in some embodiments, and the size of one end cap is 30%-80% of the size of the other end cap in some other embodiments.
The present invention provides the chip LEDs/chip LED modules mounted and fixed on the inside wall of the glass lamp tube by a bonding adhesive.
In alternative embodiment, the lamp tube can be a plastic tube, and in several embodiments, the lamp tube is a glass tube. In a preferred embodiment, the lamp tube can be a transparent glass tube, or a glass tube with coated adhesive film on the inner walls thereof.
The present invention provides the LED light bar being the bendable circuit sheet to include a wiring layer and a dielectric layer, the LED light sources are disposed on the wiring layer and are electrically connected to the power supply by the wiring layer therebetween, the wiring layer and the dielectric layer are stackingly arranged, the dielectric layer is disposed on a surface of the wiring layer which is away from the LED light sources, and is fixed to an inner circumferential surface of the lamp tube. Furthermore, the bendable circuit sheet (the LED light bar) is extending along a circumferential direction of the lamp tube, the circumferential length of the bendable circuit sheet along the inner circumferential surface of the lamp tube and the circumferential length of the inner circumferential surface of the lamp tube is at a ratio of 0.3 to 0.5. Moreover, the bendable circuit sheet can further include a circuit protection layer, the circuit protection layer can be of one layer, and the circuit protection layer can be disposed on an outermost layer of the wiring layer of the bendable circuit sheet. In another preferred embodiment, the bendable circuit sheet further includes a circuit protection layer being of two layers respectively disposed on outermost layers of the wiring layer and the dielectric layer of the bendable circuit sheet.
In embodiments of the present invention, the bendable circuit sheet can be electrically connected to the power supply by wire bonding or by soldering, not to be fixed to an inner circumferential surface of the lamp tube by forming a freely extending end portion at the two ends thereof, respectively.
The present invention provides the lamp tube to include a main region, a transition region, and a plurality of rear end regions, wherein a diameter of one of the rear end regions is less than a diameter of the main region, and the one of the rear end regions of the lamp tube is fittingly sleeved with the end cap. The transition region is formed between the main region and the rear end region. The present invention provides the bendable circuit sheet to pass through the transition region and to be electrically connected to the power supply. The present invention provides each of the transition regions to have a length of 1 mm to 4 mm in some embodiments, but other lengths are also possible for the transition region.
The present invention provides the LED tube lamp to further comprising a diffusion film layer and a reflective film layer, in which the diffusion film layer is disposed above the LED light sources, the light emitting from the LED light sources is passed through the diffusion film layer and the lamp tube. Furthermore, the reflective film layer is disposed on an inner circumferential surface of the lamp tube, and the bendable circuit sheet is disposed on the reflective film layer or one side of the reflective film layer. A ratio of a circumferential length of the reflective film layer fixed along an inner surface of the lamp tube and a circumferential length of the lamp tube is 0.3 to 0.5.
In a preferred embodiment, the diffusion film layer is made of a diffusion coating comprising at least one of calcium carbonate, halogen calcium phosphate and aluminum oxide, a thickening agent, and a ceramic activated carbon.
In an embodiment of the present invention, the diffusion film layer is an optical diffusion coating coated on an inner wall or an outer wall of the lamp tube.
In another embodiment of the present invention, the diffusion film layer is an optical diffusion coating coated directly on a surface of the LED light sources.
In another embodiment of the present invention, the diffusion film layer is an optical diffuser covering above the LED light sources without directly contacting thereof.
In one embodiment of the present invention, a reflective film layer is disposed on an inner circumferential surface of the lamp tube, and occupying a portion of the inner circumferential surface of the lamp tube along a circumferential direction thereof. The LED light bar can be bondedly attached to the inner circumferential surface of the lamp tube, and the reflective film layer can be contacting one end or two ends of the LED light bar when extending along the circumferential direction of the lamp tube. The LED light bar can be disposed above the reflective film layer or adjacently to one side of the reflective film layer.
The present invention provides the LED tube lamp to further comprising a reflective film layer. The reflective film layer is disposed on an inner circumferential surface of the lamp tube, the LED light bar is disposed on the reflective film layer or one side of the reflective film layer.
In one embodiment of the present invention, the reflective film layer can be divided into two distinct sections of a substantially equal area, the LED light bar are disposed in between the two distinct sections of the reflective film layer.
In yet another embodiment of the present invention, the LED light sources are disposed on the inner circumferential surface of the lamp tube, the reflective film layer has one or more openings configured and arranged to locations of the LED light sources correspondingly, and each of the LED light sources is disposed in one of the one or more openings of the reflective film layer, respectively.
In yet another embodiment of the present invention, the thickness of the diffusion film layer arranges from 20 μm to 30 μm.
In yet another embodiment of the present invention, the ratio of light transmittance of the diffusion film layer arranges from 85% to 96%.
In yet another embodiment of the present invention, the ratio of the light transmittance of the diffusion film layer arranges from 92% to 94% while the thickness of the diffusion film layer arranges from 200 μm to 300 μm.
The present invention provides another embodiment for the LED tube lamp, in which the LED light bar being the bendable circuit sheet, includes a plurality of wiring layers and a plurality of dielectric layers, the dielectric layers and the wiring layers are sequentially and staggerly stacked, respectively, on a surface of one wiring layer that is opposite from the surface of another wiring layer that has the LED light sources disposed thereon, the LED light sources are disposed on an uppermost layer of the wiring layers, and are electrically connected to the power support by the uppermost layer of the wiring layers.
The present invention provides a hot melt adhesive to bond together the end cap and the lamp tube, thus allowing for realization of manufacturing automation for LED tube lamps.
The present invention provides the power supply for the LED tube lamp may be in the form of a singular unit, or two individual units, and the power supply can be purchased readily from the marketplace because it is of conventional design.
The present invention provides the LED light bar to be adhesively mounted and secured on the inner wall of the lamp tube, thereby having an illumination angle of at least 330 degrees.
In a preferred embodiment, the lamp tube can be a transparent glass tube, or a glass tube with coated adhesive film on the inner walls thereof.
To solve one of the above problems, the present invention provides a LED tube lamp having a substantially uniform exterior diameter from end to end thereof by having a glass lamp tube having one or more narrowly curved end regions at two ends thereof for engaging with a plurality of end caps, and the end caps are enclosing around the narrowly curved end regions of the glass lamp tube, in which the outer diameter of the end caps is substantially equal to the outer diameter of the lamp tube thereby forming the LED tube lamp of substantially uniform exterior diameter from end to end thereof.
The present invention provides an LED tube lamp that includes a plurality of chip LEDs, an LED light bar, a lamp tube, at least two end caps, an insulation adhesive, an optical adhesive, a hot melt adhesive, a bonding adhesive, and at least one power supply.
The present invention provides the chip LEDs/(chip LED modules) mounted and fixed on the inside wall of the glass lamp tube by the bonding adhesive. The chip LED has a female plug, and containing a LED light source. The end cap is configured with a plurality of hollow conductive pins, and a power supply installed therein, where the power supply at one end thereof has a male plug, while the other end thereof has a metal pin. The male plug of the power supply is engageably fittingly inserted into the female plug of the chip LED. The other end of the power supply with the metal pin is inserted into the hollow conductive pin, thereby enabling an electrical connection. The power supply can be of one singular unit (which is disposed in one end cap) or two units located in two end caps, respectively. In an embodiment having a singular narrowly curved end region and a singular power supply, the power supply is preferred to be disposed in the end adjacent to the corresponding singular narrowly curved end region of the glass tube.
The present invention provides the insulation adhesive coated and encapsulated over the chip LEDs, while the optical adhesive is coated and encapsulated over the surfaces of the LED light source (LED chip). Thus, the entire chip LED is thereby electrically insulated from the outside, so that even when the lamp tube is partially broken into pieces, would not cause electrical shock. The end caps are secured by using a hot melt adhesive, for completing the assembling of the LED tube lamp of present invention.
The present invention provides the glass lamp tube to be curved and narrowly at the opening regions or end regions thereof, so as to be narrower in diameter at the ends thereof. The hot melt adhesive is used to secure the end caps to the narrowly curved end region of the lamp tube, so that the end region is restricted to a “transition region”. The hot melt adhesive is prevented from spillover or forming a flash region due to the presence of excessive adhesive residues. The outer diameter of the end cap and the outer diameter of the glass lamp tube should have a difference therebetween with an average tolerance of up to +/−0.2 mm, with the maximum tolerance up to +/−1 mm. Due to the substantial aligning of the center line of the end cap and the center line of the glass lamp tube combined with the fact that the width/outer diameter of the end cap and the outer diameter of the glass lamp tube (in the middle region of the lamp tube, but not including the two narrowly curved end regions at the ends thereof) are substantially equal, so that the entire LED tube lamp (assembly) appears to have an integrated planar flat surface. As a result, during shipping or transport of the LED tube lamp, the shipping packaging support or bracket would not just only make direct contact with the end caps, but also the entire LED tube lamp, including the glass lamp tube, thus entire span or length of the LED tube lamp serves or functions as being multiple load/stress points, which thereby distribute the load/stress more evenly over a wider surface, and can lead to lesser risks for breakage of the glass lamp tube.
The present invention provides the hot melt adhesive (includes a so-called commonly known as “welding mud powder”) included in the LED tube lamp to have the following material compositions: phenolic resin 2127, shellac, rosin, calcium carbonate powder, zinc oxide, and ethanol.
To solve at least one of the above problems, the present invention provides a LED tube lamp having a magnetic metal member disposed between an end cap and the end of a lamp tube thereof.
To solve at least one of the above problems, the present invention provides the end cap, configured to be attached over an end of the lamp tube, comprising an electrically insulating tubular part, sleeving over the end of the lamp tube, and a magnetic object, the magnetic object is disposed between an inner circumferential surface of the electrically insulating tubular part of the end cap and the end of the lamp tube.
The present invention provides that the magnetic object can be a magnetic metal member fixedly disposed on an inner circumferential surface of the electrically insulating tubular part, at least a portion of the magnetic metal member is disposed between the inner circumferential surface of the electrically insulating tubular part and the end of the lamp tube.
In embodiments of the present invention, the magnetic metal member and the end of the lamp tube are adhesively bonded, such as by a hot melt adhesive.
In an embodiment of the present invention, the electrically insulating tubular part further comprises a plurality of protruding portions formed on the inner circumferential direction of the electrically insulating tubular part to be extending inwardly thereof, the protruding portion is disposed between an outer circumferential surface of the magnetic metal member and the inner circumferential surface of the electrically insulating tubular part, thereby forming a gap or space therebetween, a thickness of the protruding portion is less than that of the supporting portion.
In another embodiment of the present invention, an electrically insulating tubular part sleeves over the end of the lamp tube, an inner circumferential surface of the electrically insulating tubular part has a plurality of protruding portions extending inwardly in a radial direction, and a magnetic metal member is fixedly disposed in the end cap, the protruding portions of the electrically insulating tubular part are disposed between an outer circumferential surface of the magnetic metal member and an inner circumferential surface of the electrically insulating tubular part, wherein the magnetic metal member is at least partially disposed between an inside surface of the protruding portions of the electrically insulating tubular part and the end of the lamp tube, the protruding portions are to form a plurality of gaps between the outer circumferential surface of the magnetic metal member and the inner circumferential surface of the electrically insulating tubular part, and the protruding portions are equally and spatially arranged along the inner circumferential surface of the electrically insulating tubular part, meanwhile the gaps and the protruding portions are staggeredly arranged.
To solve at least one of the above problems, the present invention provides a LED tube lamp having a lamp tube and an end cap, in which the end cap includes an electrically insulating tubular part and a thermal conductive ring, the electrically insulating tubular part has a first tubular part and a second tubular part, the first tubular part is connected to the second tubular part along an axial direction of the lamp tube, an outer diameter of the second tubular part is less than an outer diameter of the first tubular part, the thermal conductive ring sleeves over the second tubular part, whereby an outer surface of the thermal conductive ring and an outer circumferential surface of the first tubular part are substantially flush with each other. The thermal conductive ring can be a metal ring.
The present invention provides a hot melt adhesive to bond together the end cap and the lamp tube, thus allowing for realization of manufacturing automation for LED tube lights. The thermal conductive ring is adhesively bonded to the lamp tube by the hot melt adhesive. In addition, the thermal conductive ring is fixedly arranged on a circumferential surface of the electrically insulating tubular part. An inner surface of the second tubular part, the inner surface of the thermal conductive ring, the outer surface of the rear end region and the outer surface of the transition region together form an accommodation space in which the hot melt adhesive is disposed in the accommodation space, such as only partially filing thereof. Portion of the hot melt adhesive is disposed between the inner surface of the second tubular part and the outer surface of the rear end region. Upon filling and curing of the hot melt adhesive, the thermal conductive ring is bonded to an outer surface of the lamp tube by the hot melt adhesive therebetween at a first location. Upon filling and curing of the hot melt adhesive, the second tubular part is bonded to the rear end region of the lamp tube by the hot melt adhesive therebetween at a second location. Due to the difference in height between the outer surface of the rear end region and the outer surface of the main region of the lamp tube and the presence and location of the thermal conductive ring in relation to the transition region and the main region of the lamp tube, overflow or spillover of the hot melt adhesive to the main region of the lamp tube can be avoided, forsaking or avoiding having to perform manual adhesive wipe off or clean off, thus improving LED tube lamp production efficiency.
In a preferred embodiment, the lamp tube can be a transparent glass tube, or a glass tube with coated adhesive film on the inner walls thereof. In another embodiment, an end of the second tubular part located away from the first tubular part includes a plurality of notches, the notches are spatially arranged along a circumferential direction of the second tubular part.
In several of the embodiments, due to the substantial aligning of the center line of the end cap and the center line of the glass lamp tube, the width/outer diameter of the end cap, including the thermal conductive ring and the first tubular part, are substantially equal, so that the entire LED tube lamp (assembly) appears to have an integrated planar flat surface.
To solve at least one or more of the above problems, the present invention provides a LED tube lamp having a plurality of LED lead frames in which a plurality of LED chips are disposed therein, respectively.
The present invention provides an LED tube lamp that includes a plurality of LED light sources and a plurality of LED lead frames.
The present invention provides an LED tube lamp that includes a lamp tube and a plurality of LED light sources, disposed inside the lamp tube. Each of the LED light sources comprises an LED lead frame and an LED chip. The LED lead frame has two first sidewalls, two second sidewalls and a recess. The LED chip is disposed in the recess. A height of the first sidewall is lower than a height of the second sidewall.
In one embodiment, the first sidewalls of the LED lead frame are arranged along a length direction of the lamp tube, the second sidewalls of the LED lead frame are arranged along a width direction of the lamp tube.
In another embodiment, each of the first sidewalls of the LED lead frame is extending along the width direction of the lamp tube, each of the second sidewalls of the LED lead frame is extending along the length direction of the lamp tube.
The present invention provides a LED light bar to be disposed inside the lamp tube and fixed closely to an inner surface of the lamp tube. The LED light sources are mounted within the LED lead frames, respectively, which then together are mounted on the LED light bar, respectively. The LED light sources and the power supply are electrically connected by the LED light bar.
The present invention provides an LED light source, which includes an LED chip and an LED lead frame. The LED lead frame includes a recess, a first sidewall and a second sidewall. The LED chip is disposed in the recess. A height of the first sidewall is lower than a height of the second sidewall.
In an embodiment, an inner surface of the first sidewall is a sloped flat surface that is facing towards outside of the recess.
In another embodiment, an inner surface of the first sidewall is a sloped curved surface that is facing towards outside of the recess.
In an embodiment, the first sidewall of the LED lead frame is configured to have an included angle between the bottom surface of the recess and the inner surface thereof between 105 degrees to 165 degrees.
In a preferred embodiment, the included angle between the bottom surface of the recess and the inner surface of the first sidewall can be between 120 degrees and 150 degrees.
The present invention provides the LED chips mounted and fixed on the LED lead frames, respectively, by a bonding adhesive. The LED chips can be in rectangular shape as a strip with the dimension of the length side to the width side at a ratio range from 2:1 to 10:1, preferably at a ratio range from 2.5:1 to 5:1, and further preferably at a ratio range from 3:1 to 4.5:1.
In an embodiment, the LED tube lamp further includes a reflective film layer, in which the reflective film layer is disposed on two sides of the LED light bar, and is extending along a circumferential direction of the lamp tube. The reflective film layer is occupying 30% to 50% of the inner surface area of the lamp tube.
In various embodiments, the LED tube lamp has the LED light sources therein to be arranged in one or more rows, and each row of the LED light sources is extending along a length direction of the lamp tube.
In an embodiment, the LED lead frames of the LED light sources have all of the second sidewalls thereof disposed in one straight line along the length direction of the lamp tube, respectively.
In another embodiment, the LED light sources are arranged and disposed in more than one rows, and each row of the LED light sources are arranged along the length direction of the lamp tube. The LED lead frames of the LED light sources disposed in the outermost two rows along in the width direction of the lamp tube, the LED lead frames of the LED light sources have all of the second sidewalls thereof disposed in one straight line along the length direction of the lamp tube, respectively. The second sidewalls disposed on a same side of the same row are collinear to one another. The LED lead frame disposed in the outermost two rows to have two first sidewalls configured along the length direction and two second sidewalls configured along the width direction, so that the second sidewalls located at the outermost two rows can block the user's line of sight for directly seeing the LED light sources, the reduction of visual graininess unpleasing effect can thereby be achieved.
One benefit of the LED tube lamp fabricated in accordance with the embodiments of present invention is that as compared to having rigid aluminum plate or FR4 board as the LED light bar, when the lamp tube has been ruptured, the entire lamp tube is still maintaining a straight tube configuration, then the user may be under a false impression the LED tube lamp would remain usable and fully functional. As a result, electric shock can occur upon handling or installation thereof. On the other hand, because of added flexibility and bendability of the bendable circuit sheet for the LED light bar according to embodiments of present invention, the problems faced by the aluminum plate, FR4 board, conventional 3-layered flexible board having inadequate flexibility and bendability are thereby solved. Due to the adopting of the flexible substrate/bendable circuit sheet for the LED light bar of embodiments of present invention, the bendable circuit sheet (the LED light bar) renders a ruptured or broken lamp tube to being not able (unable) to maintain a straight pipe or tube configuration so as to better inform the user that the LED tube lamp is deemed unusable so as to avoid potential electric shock accidents from occurring.
Another benefit of the LED tube lamp fabricated in accordance with the embodiments of present invention is that the bendable circuit sheet (LED light bar) having a freely extending end portion together with the soldered connection between the output terminal of the power supply, and the freely extending end portion can be coiled to be fittingly accommodating inside the lamp tube, so that the freely extending end portions of the bendable circuit sheet can be deformed in shape due to contracting or curling up to fit inside the lamp tube, and when using a solder bonding technique having a pad of the power supply being of different surface to one of the surfaces of the bendable circuit sheet that is mounted with the LED light sources, a downward tension is exerted on the power supply at the connection end of the power supply and the bendable circuit sheet, so that the bendable circuit sheet with through-holes configured bond pad would form a stronger and more secure electrical connection between the bendable circuit sheet and the power supply. Another benefit of the LED tube lamp fabricated in accordance with the embodiments of present invention is that the bendable circuit sheet allows for soldering for forming solder joints between the flexible substrate and the power supply, and the bendable circuit sheet can be used to pass through the transition region and soldering bonded to the output terminal of the power supply for providing electrical coupling to the power supply, so as to avoid the usage of bonding wires, and improving upon the reliability thereof.
Another benefit of the LED tube lamp fabricated in accordance with the embodiment of present invention is that the lamp tube having the diffusion film layer coated and bonded to the inner wall thereof allows the light outputted or emitted from the LED light sources to be more uniformly transmitted through the diffusion film layer and then through the lamp tube. In other words, the diffusion film layer provides an improved illumination distribution uniformity of the light outputted by the LED light sources so as to avoid the formation of dark regions seen inside the illuminated or lit up lamp tube.
Another benefit of the LED tube lamp fabricated in accordance with the embodiment of present invention is that the applying of the diffusion film layer made of optical diffusion coating material to outer surface of the rear end region along with the hot melt adhesive would generate increased friction resistance between the end cap and the lamp tube due to the presence of the optical diffusion coating (when compared to that of an example that is without any optical diffusion coating), which is beneficial for preventing accidental detachment of the end cap from the lamp tube. In addition, using this optical diffusion coating material for forming the diffusion film layer, a superior light transmittance ratio of about 85%-96% can be achieved.
Another benefit of the LED tube light fabricated in accordance with the embodiments of present invention is that the diffusion film layer can also provide electrical isolation for reducing risk of electric shock to a user upon breakage of the lamp tube. Meanwhile, in some embodiment, the particle size of the reflective material such as strontium phosphate or barium sulfate will be much larger than the particle size of the calcium carbonate. Therefore, selecting just a small amount of reflective material in the optical diffusion coating can effectively increase the diffusion effect of light.
Another benefit of the LED tube lamp fabricated in accordance with the embodiments of present invention is that the reflective film layer when viewed by a person looking at the lamp tube from the side serve to block the LED light sources, so that the person does not directly see the LED light sources, thereby reducing the visual graininess effect. Meanwhile, reflection light passes through the reflective film layer emitted from the LED light source, can control the divergence angle of the LED tube lamp, so that more light is emitted in the direction that has been coated with the reflective film, such that the LED tube lamp has higher energy efficiency when providing same level of illumination performance. Preferably, reflectance at more than 95% can also be achievable.
Another benefit of the LED tube lamp fabricated in accordance with the embodiments of present invention is that the glass lamp tube containing an adhesive film layer would allow the broken glass pieces to be adhere together even upon breakage thereof, without forming shattered openings, thus can preventing accidental electrical shock caused by physical contact of the internal electrical conducting elements residing inside the glass lamp tube by someone, at the same time, through having the adhesive film layer of this type of material composition, would also include light diffusing and light transmitting properties, so as to achieve more evenly distributed LED lamp tube illumination, and higher light transmittance. In an embodiment, the glass lamp tube is coated with the adhesive film layer on its inside wall surface, the adhesive film layer is made primarily of calcium carbonate, along with a thickening agent, ceramic activated carbon, and deionized water, which are mixed and combined together to be evenly coated on the side wall surface of the glass tube, with average thickness of 2030 micron meters, which can lead to about 85%-96% light transmittance ratio. Finally, the deionized water is evaporated, so as to leave behind the calcium carbonate, the thickening agent, and the ceramic activated carbon.
One benefit of the LED tube lamp fabricated in accordance with the embodiment of present invention is that the magnetic metal member is out of sight when viewed by a user of the LED tube lamp, thus the flush surface of the end cap can be more aesthetically pleasing.
Another benefit of the LED tube lamp fabricated in accordance with the embodiment of present invention is that actual curing of the hot melt adhesive by the energized induction coil is performed more uniformly and done more precisely, thus the bonding of the end cap, the magnetic metal member, and the lamp tube are more secure and lasting.
Another benefit of the LED tube lamp fabricated in accordance with the embodiments of present invention is that due to the difference in height between the outer surface of the rear end region and the outer surface of the main region of the lamp tube and the presence and location of the magnetic metal member in relation to the transition region and the main region of the lamp tube, overflow or spillover of the hot melt adhesive to the main region of the lamp tube can be totally avoided, forsaking or avoiding having to perform manual adhesive wipe off or clean off, thus improving LED tube lamp production efficiency.
Another benefit of the LED tube lamp fabricated in accordance with the embodiments of present invention is that due to the substantial aligning of the center line of the end cap and the center line of the glass lamp tube, the outer diameter of the end cap and of lamp tube are substantially equal, so that the entire LED tube lamp (assembly) appears to have an integrated planar flat surface. As a result, during shipping or transport of the LED tube lamp, the shipping packaging support or bracket would not just only make direct contact with the end caps, but also the entire LED tube lamp, including the glass lamp tube, thus entire span or length of the LED tube lamp serves or functions as being multiple load/stress points, which thereby distribute the load/stress more evenly over a wider surface, and can lead to lesser risks for breakage of the glass lamp tube.
One benefit of the LED tube lamp fabricated in accordance with the embodiments of present invention is that when the user is viewing along the width direction toward the lamp tube, the second sidewall can block the line of sight of the user to the LED light source, thus reducing unappealing grainy spots. In addition, the sloped first sidewall also enhances light extraction from the LED light source.
Another benefit of the LED tube lamp fabricated in accordance with the embodiments of present invention is that by having the LED lead frames with the height of the first sidewall being lower than that of the second sidewall, more light emitted from the LED chips can be effectively transmitted along a length direction out of the recesses of the LED lead frames, while lesser light can be transmitted along a width direction out of the recesses thereof.
Meanwhile, yet another benefit of the LED tube lamp fabricated in accordance with the embodiments of present invention is that the LED lead frames serve to protect the LED chips from potential damages.
The present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which:
The present invention will now be described more specifically with reference to the following embodiments. It is to be noted that the following descriptions of preferred embodiments of this invention are presented herein for purpose of illustration and description only. It is not intended to be exhaustive or to be limited to the precise form disclosed.
According to an embodiment of present invention, an LED tube lamp is shown in
In the present embodiment, the lamp tube 1 is made of tempered glass. The method for strengthening or tempering of glass tube can be done by a chemical tempering method or a physical tempering method for further processing on the glass lamp tube 1. For example, the chemical tempering method is to use other alkali metal ions to exchange with the Na ions or K ions. Other alkali metal ions and the sodium (Na) ions or potassium (K) ions on the glass surface are exchanged, in which an ion exchange layer is formed on the glass surface. When cooled to room temperature, the glass is then under tension on the inside, while under compression on the outside thereof, so as to achieve the purpose of increased strength, including but not limited to the following glass tempering methods: high temperature type ion exchange method, the low temperature type ion exchange method, dealkalization, surface crystallization, sodium silicate strengthening method. High-temperature ion exchange method includes the following steps. First, glass containing sodium oxide (Na2O) or potassium oxide (K2O) in the temperature range of the softening point and glass transition point are inserted into molten salt of lithium, so that the Na ions in the glass are exchanged for Li ions in the molten salt. Later, the glass is then cooled to room temperature, since the surface layer containing Li ions has different expansion coefficient with respect to the inner layer containing Na ions or K ions, thus the surface produces residual stress and is reinforced. Meanwhile, the glass containing AL2O3, TiO2 and other components, by performing ion exchange, can produce glass crystals of extremely low coefficient of expansion. The crystallized glass surface after cooling produces significant amount of pressure, up to 700 MPa, which can enhance the strength of glass. Low-temperature ion exchange method includes the following steps: First, a monovalent cation (e.g., K ions) undergoes ion exchange with the alkali ions (e.g. Na ion) on the surface layer at a temperature range that is lower than the strain point temperature, so as to allow the K ions penetrating the surface. For example, for manufacturing a Na2O+CaO+SiO2 system glass, the glass can be impregnated for ten hours at more than four hundred degrees in the molten salt. The low temperature ion exchange method can easily obtain glass of higher strength, and the processing method is simple, does not damage the transparent nature of the glass surface, and not undergo shape distortion. Dealkalization includes of treating glass using platinum (Pt) catalyst along with sulfurous acid gas and water in a high temperature atmosphere. The Na+ ions are migrated out and bleed from the glass surface to be reacted with the Pt catalyst, so that whereby the surface layer becomes a SiO2 enriched layer, which results in being a low expansion glass and produces compressive stress upon cooling. Surface crystallization method and the high temperature type ion exchange method are different, but only the surface layer is treated by heat treatment to form low expansion coefficient microcrystals on the glass surface, thus reinforcing the glass. Sodium silicate glass strengthening method is a tempering method using sodium silicate (water glass) in water solution at 100 degrees Celsius and several atmospheres of pressure treatment, where a stronger/higher strength glass surface that is harder to scratch is thereby produced. The above glass tempering methods described including physical tempering methods and chemical tempering methods, in which various combinations of different tempering methods can also be combined together.
In the illustrated embodiment as shown in
Referring to
In the present embodiment, the outer diameter of the end caps 3 are the same as the outer diameter of the main region 102, and the tolerance for the outer diameter measurements thereof are preferred to be within +/−0.2 millimeter (mm), and should not exceed +/−1.0 millimeter (mm). The difference between an outer diameter of the rear end region 101 and the outer diameter of the main region 102 can be 1 mm to 10 mm for typical product applications. Meanwhile, for preferred embodiment, the difference between the outer diameter of the rear end region 101 and the outer diameter of the main region 102 can be 2 mm to 7 mm. The length of the transition region 103 along the axial direction of the lamp tube 1 is between 1 mm to 4 mm. Upon experimentation, it was found that when the length of the transition region 103 along the axial direction of the lamp tube 1 is either less than 1 mm or more than 4 mm, problems would arise due to insufficient strength or reduction in light illumination surface of the lamp tube. In alternative embodiment, the transition region 103 can be without curve or arc in shape. Upon adopting the T8 standard lamp format as an example, the outer diameter of the rear end region 101 is configured between 20.9 mm to 23 mm. Meanwhile, if the outer diameter of the rear end region 101 is less than 20.9 mm, the inner diameter of the rear end region 101 would be too small, thus rendering inability of the power supply to be fittingly inserted into the lamp tube 1. The outer diameter of the main region 102 is preferably configured to be between 25 mm to 28 mm.
Referring to
Referring to
The hot melt adhesive 6 (includes a so-called commonly known as “welding mud powder”) includes phenolic resin 2127, shellac, rosin, calcium carbonate powder, zinc oxide, and ethanol, etc. The lamp tube 1 at the rear end region 101 and the transition region 103 (as shown in
In the present embodiment, the electrically insulating tubular part 302 of the end cap 3 includes a first tubular part 302a and a second tubular part 302b. The first tubular part 302a and the second tubular part 302b are connected along an axis of extension of the electrically insulating tubular part 302 or an axial direction of the lamp tube 1. The outer diameter of the second tubular part 302b is less than the outer diameter of the first tubular part 302a. The outer diameter difference between the first tubular part 302a and the second tubular part 302b is between 0.15 mm to 0.30 mm. The thermal conductive ring 303 is fixedly configured over and surrounding the outer circumferential surface of the second tubular part 302b. The outer surface of the thermal conductive ring 303 is coplanar or substantially flush with respect to the outer circumferential surface of the first tubular part 302a, in other words, the thermal conductive ring 303 and the first tubular part 302a have substantially uniform exterior diameters from end to end. As a result, the end cap 3 achieves an outer appearance of smooth and substantially uniform tubular structure. In the embodiment, ratio of the length of the thermal conductive ring 303 along the axial direction of the end cap 3 with respect to the axial length of the electrically insulating tubular part 302 is from 1:2.5 to 1:5. In the present embodiment, the inner surface of the second tubular part 302b and the inner surface of the thermal conductive ring 303, the outer surface of the rear end region 101 and the outer surface of the transition region 103 together form an accommodation space. In order to ensure bonding longevity using the hot melt adhesive, in the present embodiment, the second tubular part 302b is at least partially disposed around the lamp tube 1, the hot melt adhesive 6 is at least partially filled in an overlapped region (shown by a broken/dashed line identified as “A” in
During fabrication of the LED tube lamp, the rear end region 101 of the lamp tube 1 is inserted into one end of the end cap 3, the axial length of the portion of the rear end region 101 of the lamp tube 1 which had been inserted into the end cap 3 accounts for one-third (⅓) to two-thirds (⅔) of the total length of the thermal conductive ring 303 in an axial direction thereof. One benefit is that, the hollow conductive pins 301 and the thermal conductive ring 303 have sufficient creepage distance therebetween, and thus is not easy to form a short circuit leading to dangerous electric shock to individuals. On the other hand, due to the electrically insulating effect of the electrically insulating tubular part 302, thus the creepage distance between the hollow conductive pin 301 and the thermal conductive ring 303 is increased, and thus less people are likely to obtain electric shock caused by operating and testing under high voltage conditions. In this embodiment, the electrically insulating tube 302 in general state, is not a good conductor of electricity and/or is not used for conducting purposes, but not limited to the use made of plastics, ceramics and other materials. Furthermore, for the hot melt adhesive 6 disposed in the inner surface of the second tubular part 302b, due to presence of the second tubular part 302b interposed between the hot melt adhesive 6 and the thermal conductive ring 303, therefore the heat conducted from the thermal conductive ring 303 to the hot melt adhesive 6 may be reduced. Thus, referring to
The thermal conductive ring 303 can be made of various heat conducting materials, the thermal conductive ring 303 of the present embodiment is a metal sheet, such as aluminum alloy. The second tubular part 302b is sleeved with the thermal conductive ring 303 being tubular or ring shaped. The electrically insulating tubular part 302 may be made of electrically insulating material, but would have low thermal conductivity so as to prevent the heat conduction to reach the power supply components located inside the end cap 3, which then negatively affect performance of the power supply components. In this embodiment, the electrically insulating tubular part 302 is a plastic tube. In other embodiments, the thermal conductive ring 303 may also be formed by a plurality of metal plates arranged along a plurality of second tubular part 302b in either circumferentially-spaced or not circumferentially-spaced arrangement. In other embodiments, the end cap may take on or have other structures. Referring to
In other embodiments, the end cap 3 can also be made of all-metal, which requires to further provide an electrically insulating member beneath the hollow conductive pins as safety feature for accommodating high voltage usage.
In other embodiments, the magnetic metal member 9 can have at least one opening 901 as shown in
Referring again to
In the embodiment, the LED light bar 2 is fixed by the adhesive sheet 4 to an inner circumferential surface of the lamp tube 1, so that the LED light sources 202 are mounted in the inner circumferential surface of the lamp tube 1, which can increase the illumination angle of the LED light sources 202, thereby expanding the viewing angle, so that an excess of 330 degrees viewing angle is possible to achieve. Through the utilization of applying the insulation adhesive sheet 7 on the LED light bar 2 and applying of the optical adhesive sheet 8 on the LED light sources, the electrical insulation of the LED light bar 2 is provided, so that even when the lamp tube 1 is broken, electrical shock does not occur, thereby improving safety.
Furthermore, the LED light bar 2 may be a flexible substrate, an aluminum plate or strip, or a FR4 board, in an alternative embodiment. Since the lamp tube 1 of the embodiment is a glass tube. If the LED light bar 2 adopts rigid aluminum plate or FR4 board, when the lamp tube has been ruptured, e.g., broken into two parts, the entire lamp tube is still able to maintain a straight pipe or tube configuration, then the user may be under a false impression the LED tube lamp can remain usable and fully functional and easy to cause electric shock upon handling or installation thereof. Because of added flexibility and bendability of the flexible substrate for the LED light bar 2, the problem faced by the aluminum plate, FR4 board, conventional 3-layered flexible board having inadequate flexibility and bendability are thereby solved. Due to the adopting of the flexible substrate/bendable circuit sheet for the LED light bar 2 of present embodiment, the LED light bar 2 allows a ruptured or broken lamp tube not to be able to maintain a straight pipe or tube configuration so as to better inform the user that the LED tube lamp is rendered unusable so as to avoid potential electric shock accidents from occurring. The following are further description of the flexible substrate/bendable circuit sheet used as the LED light bar 2. The flexible substrate/bendable circuit sheet and the output terminal of the power supply 5 can be connected by wire bonding, the male plug 501 and the female plug 201, or connected by soldering joint. The method for securing the LED light bar 2 is same as before, one side of the flexible substrate is bonded to the inner surface of the lamp tube 1 by using the adhesive sheet 4, and the two ends of the flexible substrate/bendable circuit sheet can be either bonded (fixed) or not bonded to the inner surface of the lamp tube 1. If the two ends of the flexible substrate are not bonded or fixed to the inner surface of the lamp tube, and also if the wire bonding is used, the bonding wires are prone to be possibly broken apart due to sporadic motions caused by subsequent transport activities as well as being freely to move at the two ends of the flexible substrate/bendable circuit sheet. Therefore, a better option may be by soldering for forming solder joints between the flexible substrate and the power supply. Referring to
Referring to illustrated embodiment of
In a preferred embodiment, the lamp tube 1 can be a glass tube with a coated adhesive film on the inner wall thereof (not shown). The coated adhesive film also serves to isolate and segregate the inside and the outside contents of the lamp tube 1 upon being ruptured thereof. The coated adhesive film material includes methyl vinyl silicone oil, hydro silicone oil, Xylene, and calcium carbonate The methyl vinyl silicone oil chemical formula is: (C2H8OSi)n.C2H3. The hydrosilicon oil chemical formula is: C3H9OSi.(CH4OSi)n.C3H9Si; and the product produced is polydimethylsiloxane (silicone elastomer), which has chemical formula as follow:
Xylene is used as an auxiliary material. Upon solidifying or hardening of the coated adhesive film when coated on the inner surface of the lamp tube 1, the xylene will be volatilized and removed. The xylene is mainly used for the purpose of adjusting the degree of adhesion or adhesiveness, which can then adjust the thickness of the bonding adhesive. In the present embodiment, the thickness of the coated adhesive film can be between 10 to 800 micron meters (μm), and the preferred thickness of the coated adhesive film can be between 100 to 140 micron meters (μm). This is because the bonding adhesive thickness being less than 100 micron meters, does not have sufficient shatterproof capability for the glass tube, and thus the glass tube is prone to crack or shatter. At above 140 micron meters of bonding adhesive thickness would reduce the light transmittance rate, and also increase material cost. Vinyl silicone oil+hydrosilicone oil allowable ratio range is (19.8-20.2):(20.2-20.6), but if exceeding this allowable ratio range, would thereby negatively affect the adhesiveness or bonding strength. The allowable ratio range for the xylene and calcium carbonate is (2-6):(2-6), and if lesser than the lowest ratio, the light transmittance of the lamp tube will be increased, but grainy spots would be produced or resulted from illumination of the LED lamp tube, negatively affect illumination quality and effect.
If the LED light bar 2 is configured to be a flexible substrate, no coated adhesive film is thereby required.
To improve the illumination efficiency of the LED tube lamp, the lamp tube 1 has been modified according to a first embodiment of present invention by having a diffusion film layer 13 coated and bonded to the inner wall thereof as shown in
Specifically, average thickness of the diffusion film layer or the optical diffusion coating falls between 20˜30 μm after being coated on the inner circumferential surface of the glass tube, where finally the deionized water will be evaporated, leaving behind the calcium carbonate, ceramic activated carbon and the thickener. Using this optical diffusion coating material for forming the diffusion film layer 13, a light transmittance of the diffusion film layer 13 about 90% can be achieved. Generally speaking, the light transmittance ratio of the diffusion film layer 13 is from 85% to 96%. Furthermore, in another possible embodiment, the light transmittance ratio of the diffusion film layer can be 92%-94% while the thickness range is between 200-300 μm which can have other effect. In addition, this diffusion film layer 13 can also provide electrical isolation for reducing risk of electric shock to a user upon breakage of the lamp tube. Furthermore, the diffusion film layer 13 provides an improved illumination distribution uniformity of the light outputted by the LED light sources 202 so as to avoid the formation of dark regions seen inside the illuminated or lit up lamp tube 1. In other embodiments, the optical diffusion coating can also be made of strontium phosphate (or a mixture of calcium carbonate and strontium phosphate) along with a thickening agent, ceramic activated carbon and deionized water, and the coating thickness can be same as that of present embodiment. In another preferred embodiment, the optical diffusion coating material may be calcium carbonate-based material with a small amount of reflective material (such as strontium phosphate or barium sulfate), the thickener, deionizes water and carbon activated ceramic to be coated onto the inner circumferential surface of the glass tube with the average thickness of the optical diffusion coating falls between 20˜30 μm. Then, finally the deionized water will be evaporated, leaving behind the calcium carbonate, the reflective material, ceramic activated carbon and the thickener. The diffusion phenomena in microscopic terms, light is reflected by particles. The particle size of the reflective material such as strontium phosphate or barium sulfate will be much larger than the particle size of the calcium carbonate. Therefore, selecting a small amount of reflective material in the optical diffusion coating can effectively increase the diffusion effect of light. In other embodiments, halogen calcium phosphate or aluminum oxide can also be served as the main material for forming the diffusion film layer 13.
Furthermore, as shown in
In another embodiment, the reflective film layer 12 and the LED light bar 2 are contacted on one side thereof as shown in
In other embodiments, the width of the LED light bar 2 (along the circumferential direction of the lamp tube) can be widened to occupy a circumference area of the inner circumferential surface of the lamp tube 1 at a ratio between 0.3 to 0.5, in which the widened portion of the LED light bar 2 can provide reflective effect similar to the reflective film. As described in the above embodiment, the LED light bar 2 may be coated with a circuit protection layer, the circuit protection layer may be an ink material, providing an increased reflective function, with a widened flexible substrate using the LED light sources as starting point to be circumferentially extending, so that the light is more concentrated. In the present embodiment, the circuit protection layer is coated on just the top side of the LED light bar 2 (in other words, being disposed on an outermost layer of the LED light bar 2 (or bendable circuit sheet).
In the embodiment shown in
Referring to
In one embodiment, the LED light bar includes a dielectric layer and one wiring layer, in which the dielectric layer and the wiring layer are arranged in a stacking manner.
The narrowly curved end regions of the glass tube can reside at two ends, or can be configured at just one end thereof in different embodiments. In alternative embodiment, the LED tube lamp to further includes a diffusion layer (not shown) and a reflective film layer 12, in which the diffusion layer is disposed above the LED light sources 202, the light emitting from the LED light sources 202 is passed through the diffusion layer and the lamp tube 1. Furthermore, the diffusion film layer can be an optical diffusion covering above the LED light sources without directly contacting thereof. In addition, the LED light sources 202 can be bondedly attached to the inner circumferential surface of the lamp tube. In other embodiment, the magnetic metal member 9 can be a magnetic substance that is magnetic without being made of metal. The magnetic substance can be mixed in the hot melt adhesive.
While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14677899 | Apr 2015 | US |
| Child | 14818194 | US | |
| Parent | 14724840 | May 2015 | US |
| Child | 14677899 | US |
