Patent Grant
9613792
The present disclosure relates generally to ultraviolet curing lamps, and more particularly, to a microwave-powered ultraviolet (UV) light source, lamp module, and lamp system.
The microwave energy generated by the magnetron 11 is supplied to the cavity 13 thorough the waveguide 12. Inside the cavity 13, the microwave energy is coupled to the UV bulb 14, and excites one or more elements contained in the UV lamp 14 (for example, Hg), causing the UV bulb 14 to emit ultraviolet (UV) light of a line wavelength (e.g., 365 nm). In
More recently, a new type of UV lamp that does not require a cavity has been developed. For example, U.S. Pat. No. 7,095,163 describes one example of the cavity-less UV lamp.
In a UV lamp system comprising a plurality of electrodeless bulbs, a separate lamp may be required for each wavelength range for which UV exposure is required. In addition, because each bulb of the plurality of bulbs emits a sufficient amount of light to cure a substrate in a relatively narrow wavelength range. As a result, broadband exposure of a substrate cannot be achieved.
The above-described problems are addressed and a technical solution is achieved in the art by providing an elongated light source envelope having an inner wall and an outer wall formed around a longitudinal axis. The inner wall and outer wall may be connected at a first axial end by a first side wall and a second axial end by a second side wall. The inner wall, the outer wall, the first side wall, and the second side wall may define an enclosed space internal to the envelope. The light source envelope may further comprise one or more walls formed between the outer wall and the inner wall to further form at least a first enclosed region and a second enclosed region within the enclosed space.
The above-described problems are addressed and a technical solution is achieved in the art by providing a light source module comprising an elongated light source envelope having an inner wall and an outer wall formed around a longitudinal axis. The inner wall and the outer wall may be connected at a first axial end by a first side wall and a second axial end by a second side wall. The inner wall, the outer wall, the first side wall, and the second side wall may define an enclosed space internal to the envelope. The inner wall may define an inner space around the longitudinal axis. The light source envelope may further comprise one or more walls formed between the inner wall and the outer wall to further form at least a first enclosed region and a second enclosed region within the enclosed space. The light source module may further comprise an antenna inserted in the inner space.
The above-described problems are addressed and a technical solution is achieved in the art by providing lamp system, comprising a housing, a radio frequency (RF) microwave energy source located within the housing, an antenna coupled to the RF or microwave energy source, and an elongated light source envelope radiatively coupled to the RF or microwave energy source. The elongated light source envelope may comprise an inner wall and an outer wall formed around a longitudinal axis. The inner wall and the outer wall may be connected at a first axial end by a first side wall and a second axial end by a second side wall. The inner wall, the outer wall, the first side wall, and the second side wall may define an enclosed space internal to the envelope. The inner wall may define an inner space around the longitudinal axis. The elongated light source may further comprise one or more walls formed between the inner wall and the outer wall to form at least a first enclosed region and a second enclosed region within the enclosed space. In an example, the antenna may be inserted in the inner space.
The present disclosure will be more readily understood from the detailed description of examples presented below considered in conjunction with the attached drawings, of which:
It is to be understood that the attached drawings are for purposes of illustrating the concepts of the disclosure and may not be to scale.
The light source envelope 30 may comprise an outer wall 32, an inner wall 34, and side walls 36. The outer wall 32 and the inner wall 34 may be formed around a longitudinal axis 37. The outer wall 32 and the inner wall 34 may be connected at a first axial end by a first side wall 36a and a second axial end by a second side wall 36b. The outer wall 32, the inner wall 34, the first side wall 36a, and the second side wall 36b may define an enclosed space 35 internal to the light source envelope 30. The enclosed space 35 may be maintained at a reduced pressure compared to the ambient surroundings. In an example, the walls 32, 34, 36a, 36b may be made of a material that permits the transmission of a high level of ultraviolet (UV) radiation transmission, such as a glass. In one example, the glass is quartz. In another example, the walls 32, 34, 36a, 36b may be formed of sapphire. The enclosed space 35 may be further divided into a plurality of enclosed regions (e.g., 38a, 38b, forming the two enclosed regions shown in FIGS. 3A-3C) by internal walls 40. The internal walls 40 may be formed of the same material as the outer wall 32, the inner wall 34, and the side walls 36a, 36b. In an example, the side walls 36a, 36b may be formed in corresponding planes substantially perpendicular to the longitudinal axis 37.
In an example, at least one enclosed region (e.g., 38a) of the plurality of enclosed regions may be configured to emit a different spectrum of ultraviolet radiation from the other enclosed regions (e.g., 38b-38d) in response to, for example, excitation by microwave radiation. In another example, each of the enclosed regions 38a-38d may be configured to emit different spectrums of ultraviolet light. In an example, wavelengths of light emittable by plurality of enclosed regions 38a-38d may be adjustable. In an example, a first enclosed region (e.g., 38a) may be filled with a first fill material and a second enclosed region (e.g., 38b) may be filled with a second fill material different from the first fill material. In an example, a third enclosed region (e.g., 38c) may be filled with a third fill material; a fourth enclosed region (e.g., 38d) may be filled with a fourth filled material, etc. In an example, the wavelengths of light emittable from each enclosed region of the plurality of enclosed regions (e.g., 38a-38d) may be adjusted by varying a type of fill material or an amount of fill material in a corresponding one of the plurality of enclosed regions (e.g., 38a-38d), respectively.
In an example, the principal radiation emitting constituent of the electrodeless ultraviolet light source envelope may be mercury. Additive materials, such as metal halides, can be included in the fill glass in relatively low concentrations compared to the mercury. The mercury and additive materials, when vaporized and ionized, will emit the characteristic wavelengths of their component molecules. In addition, short wavelength photons emitted by the mercury may have sufficiently high energy so that when a photon-molecule collision occurs, an additive material will re-emit at its characteristic wavelengths. Additive emission and this “fluorescence” may be exhibited as an enrichment of the spectral output in longer UV wavelengths.
In an example, two or more of the plurality of enclosed regions 38a-38d may have different major emission peak wavelengths. In an example, the different major emission peak wavelengths may be selected from ranges comprising 170-240 nm, 250-330 nm, 340-390 nm, or 400-470 nm. As a result, the two or more enclosed regions 38a-38d may be configured to emit a broadband of light wavelengths resulting in a substantially broadband UV light being emitted from the light source envelope 30.
Differing spectral outputs of different types of bulbs can produce varying cure results in different inks and coatings. More specifically, the H bulb spectrum is effective in producing hard surface cures and high gloss finishes. The D bulb spectrum, on the other hand, because of the greater penetration of its longer wavelengths, may be more suitable for curing pigmented materials and thick sections of clear materials. The V bulb spectrum may be especially suited for curing white inks and basecoats, which typically contain high loadings of TiO2.
In an example, the enclosed regions 38a-38d may emit different spectrums of ultraviolet radiation. In one example, one enclosed region 38a of the bulb 30 of
In an example, the bulbs 30, 50, 60 may perform a variety of different functions, such as providing a high gloss surface cure and a deep cure at the same time. Other applications may include the curing a plurality of different materials, each of which is sensitive to a respective different wavelength(s) emitted by the different enclosed regions 38a-38d.
The light source module 80 may further comprise an antenna 70 inserted in the inner space 42 (e.g., an opening) around the longitudinal axis 37. The first enclosed region 38a may be configured to emit a different spectrum of ultraviolet radiation from the second enclosed region (not shown) in response to excitation by microwave radiation.
In an example, the antenna 70 may comprise an antenna lead. In an example, the antenna lead may be an exposed inner conductor of a coaxial cable 72. The coaxial cable 72 may comprise the inner conductor, an insulator, and an outer conductor. The insulator may be made of a heat resistant material resistant to heat emitted by the lamp module 80. The heat resistant material may be, for example, a ceramic.
In an example, the antenna lead may be inserted into the inner space 42 from first open end 44 proximal to the inner space 42 around the longitudinal axis 37, and heat generated by the antenna 72 and the light source envelope 30 while the lamp module 80 is operated may be conducted through the second open end 46.
In an example, the coaxial cable 72 may be configured to be connected to a radio frequency (RF) or microwave energy source. The RF or microwave energy source (not shown) may be a magnetron.
In an example, the side walls 36a, 36b may be formed in corresponding planes substantially perpendicular to the longitudinal axis 37. The light source envelope 30 may have substantially cylindrical shape. In an example, the light source envelope 30 may be electrodeless. In an example, the light source envelope 30 may have additional enclosed regions separated from the first enclosed region 38a and second enclosed region 38b (not shown) by additional internal walls 40.
In an example, the first enclosed region 38a may be filled with a first fill material and the second enclosed region 38b may be filled with a second fill material different from the first fill material. In an example, the wavelengths of light emittable by the first enclosed region 38a and the second enclosed region 38b are adjustable. The wavelengths of light emittable by the first enclosed region 38a and the second enclosed region 38b may be adjusted by varying a type of fill material or an amount of fill material in the first enclosed region 38a and the second enclosed region 38b, respectively.
In an example, the first enclosed region 38a and the second enclosed region 38b may have different major emission peak wavelengths. The different major emission peak wavelengths may be selected from ranges comprising 170-240 nm, 250-330 nm, 340-390 nm, or 400-470 nm. The first enclosed region 38a and the second enclosed region 38b may be configured to emit a broadband of light wavelengths resulting in a substantially broadband UV light being emitted from the light source envelope 30.
In an example, the light source module 80 may further comprise a reflector (not shown) located around the outer wall of the light source envelope.
More particularly, the elongated light source envelope (e.g., 30, 40, 50) may comprise an inner wall 34 and an outer wall 32 formed around a longitudinal axis 37. The inner wall 34 and the outer wall 32 may be connected at a first axial end by a first side wall 36a and a second axial end by a second side wall 36b. The inner wall 34, the outer wall 32, the first side wall 36a, and the second side wall 36b may define an enclosed space 35 internal to the envelope (e.g., 30, 40, 50). The inner wall 34 may define an inner space 42 around the longitudinal axis 37. The elongated light source envelope (e.g., 30, 40, 50) may further comprise one or more walls 40 formed between the inner wall 34 and the outer wall 32 to form at least a first enclosed region 38a and a second enclosed region 38b within the enclosed space 35. In an example, the antenna 70 may be inserted in the inner space 42.
In an example, the antenna 70 may comprise an antenna lead having a first end proximal to the inner space 42 around the longitudinal axis 37 and a second end configured to be connected to a radio frequency (RF) or microwave energy source 92 (e.g., a magnetron). In an example, the antenna lead may be an exposed inner conductor of a coaxial cable 72. The coaxial cable 72 may comprise the inner conductor, an insulator, and an outer conductor. The insulator may be made of a heat resistant material resistant to heat emitted by the lamp module. The heat resistant material may be, for example, a ceramic.
In an example, the first side wall 36a and the second side wall 36b may be formed in corresponding planes substantially perpendicular to the longitudinal axis 37. The light source envelope (e.g., 30, 40, 50) may have a substantially cylindrical shape. In an example, the light source envelope (e.g., 30, 40, 50) may be electrodeless. In an example, the light source envelope (e.g., 30, 40, 50) may have additional enclosed regions separated from the first enclosed region and second enclosed region by additional internal walls 40.
In an example, the light source envelope (e.g., 30, 40, 50) may have a first open end 44 and a second open end 46 enclosing the inner space 42. The antenna lead may be inserted into inner space 42 from the first open end 44, and heat generated by the antenna 70 and the light source envelope (e.g., 30, 40, 50) while the UV lamp module 80 is operated may be conducted through the second open end 46.
In an example, the first enclosed region 38a may be filled with a first fill material and the second enclosed region 38b may be filled with a second fill material different from the first fill material. In an example, the wavelengths of light emittable by the first enclosed region 38a and the second enclosed region 38b may be adjustable. The wavelengths of light emittable by the first enclosed region 38a and the second enclosed region 38b may be adjusted by varying a type of fill material or an amount of fill material in the first enclosed region and the second enclosed region, respectively.
In an example, the first enclosed region 38a and the second enclosed region 38b may have different major emission peak wavelengths. The different major emission peak wavelengths may be selected from ranges comprising 170-240 nm, 250-330 nm, 340-390 nm, or 400-470 nm. The first enclosed region 38a and the second enclosed region 38b may be configured to emit a broadband of light wavelengths resulting in a substantially broadband UV light being emitted from the light source envelope.
In an example, the UV light source module 80 may further comprise a reflector 94 located around the outer wall 32 of the light source envelope (e.g., 30, 40, 50).
It is to be understood that the above description is intended to be illustrative, and not restrictive. Many other embodiments will be apparent to those of skill in the art upon reading and understanding the above description. Although the present disclosure has been described with reference to specific exemplary embodiments, it will be recognized that the disclosure is not limited to the embodiments described, but can be practiced with modification and alteration within the spirit and scope of the appended claims. Accordingly, the specification and drawings are to be regarded in an illustrative sense rather than a restrictive sense. The scope of the disclosure should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.
This application claims the benefit of U.S. provisional patent application No. 61/791,169 filed Mar. 15, 2013, the disclosure of which is incorporated herein by reference in its entirety.
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