EP2144275A2

EP2144275A2 - Light assembly having inner illumination device

Info

Publication number: EP2144275A2
Application number: EP20090164958
Authority: EP
Inventors: Wei-ping SHAO; Shou-Yi Hung; Ping-Sung Lu
Original assignee: Candle Laboratory Co Ltd
Current assignee: Candle Laboratory Co Ltd
Priority date: 2008-07-08
Filing date: 2009-07-08
Publication date: 2010-01-13
Also published as: JP3153766U; EP2144275A3

Abstract

A light assembly having an illumination device disposed therein is provided. The light assembly includes an illumination device, an envelope, and a light-processing layer. The envelope encircles the illumination device. The light-processing layer is disposed on an inner surface of the envelope; as such, when light is emitted from the illumination device, the light-processing layer may alter the wavelength composition of the light and/or diffuse the light.

Description

RELATED APPLICATIONS

This application claims priority to Taiwan Application Serial Number 97212108, filed July 08, 2008 , Taiwan Application Serial Number 97212242, filed July 10, 2008 , and Taiwan Application Serial Number 98207483, filed May 01, 2009 , which are herein incorporated by reference.

BACKGROUND

Field of Invention

The present invention relates to a light assembly, more particularly to a light assembly having at least one illumination device disposed therein.

Description of Related Art

Illumination apparatuses play an important role in our daily life. Depending on the principles of light generation, illumination apparatuses may be categorized into incandescent lamps, halogen lamps, fluorescent lamps, arc lamps, light emitting diodes (LEDs) and discharge lamps.
Incandescent lamps and hot cathode fluorescent lamps (HCFLs) are the most commonly used illuminating device in daily lighting applications. The use of LEDs in daily illumination is limited due to the nature of the LED material; however, future applications thereof are anticipated.
Conventional HCFLs are classified into various types rage from Type T5 to T12 depending on their sizes and illumination efficiencies. However, each type of the HCFLs may have their own advantages and disadvantages regarding their respective size, color rendering property, power consumption, efficiency, service life, and/or sale price.
In view of the pursuit of ideal illumination apparatuses, there is a need for a novel light assembly.

SUMMARY

The following presents a simplified summary of the disclosure in order to provide a basic understanding to the reader. This summary is not an extensive overview of the disclosure and it does not identify key/critical elements of the present invention or delineate the scope of the present invention. Its sole purpose is to present some concepts disclosed herein in a simplified form as a prelude to the more detailed description that is presented later.
In one aspect, the present invention is directed to a light assembly. The light assembly comprises an illumination device, an envelope, and a light-processing layer. The envelope encircles the illumination device. The light-processing layer is disposed on an inner surface of the envelope; as such, when light is emitted from the illumination device, the light-processing layer may alter the wavelength composition of the light or diffuse the light.
According to embodiments of the present invention, the light-processing layer may be a wavelength-converting layer, a diffusion layer, or a combination thereof. The wavelength-converting layer may alter the wavelength composition of the light emitted from the illumination device. The diffusion layer may diffuse the light emitted from the illumination device so that the light distribution along the peripheral of the envelope is uniform.
In another aspect, the present invention is directed to a light assembly. The light assembly comprises at least one illumination device, an envelope, an electrode set, and a wavelength-converting layer and/or a diffusion layer. The illumination device is operable to emit a light. The envelope encircles the illumination device and is light-transmissive. The wavelength-converting layer and/or the diffusion layer may be disposed on an inner surface of the envelope. The electrode set is disposed on one distal end of the envelope and electrically connected to the illumination device.
According to various embodiments of the present invention, the illumination device may be an ultraviolet lamp, a cold cathode fluorescent lamp (CCFL), a light emitting diode (LED) or an ultraviolet light emitting diode (UV LED). According to various embodiments of the present invention, the envelope may have a shape of a light tube or a light bulb.
In sum, the light assembly according to embodiments of the present invention has the characteristics such as low power consumption, high illumination efficiency, long service life, and low cost, which altogether make the light assembly a candidate for replacing current illumination apparatus. According to the spirit of the present invention, the shape and size of the light assembly may follow that of the commercial light tubes or light bulbs, and hence, the light assembly of the embodiments of the present invention may be fitted into the light sockets used to accommodate those commercial light tubes or light bulbs.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be made by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, as the invention may admit to other equally effective embodiments.

FIG. 1 is a schematic diagram illustrating a light assembly according to one embodiment of the present invention.
FIG. 2A is a cross-sectional diagram illustrating a light assembly according to another embodiment of the present invention.
FIG. 2B is a cross-sectional diagram illustrating a light assembly according to another embodiment of the present invention.
FIG. 3A is a cross-sectional diagram illustrating a light assembly according to another embodiment of the present invention.
FIG. 3B is an exploded view illustrating a light assembly according to another embodiment of the present invention.
FIG. 3C is a schematic diagram illustrating a light assembly according to another embodiment of the present invention.
FIG. 4 is a schematic diagram illustrating a light assembly according to another embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The detailed description provided below in connection with the appended drawings is intended as a description of the present examples and is not intended to represent the only forms in which the present example may be constructed or utilized. The description sets forth the functions of the example for constructing the examples. However, the same or equivalent functions may be accomplished by different examples.
In one aspect, the present invention is directed to a light assembly. The light assembly comprises an illumination device, an envelope, and a light-processing layer. The envelope encircles the illumination device. The light-processing layer is disposed on an inner surface of the envelope; as such, when light is emitted from the illumination device, the light-processing layer may alter the wavelength composition of the emitted light and/or cause the emitted light to diffuse.
FIG. 1 is a schematic diagram illustrating a light assembly 100 according to one embodiment of the present invention. In FIG. 1, the light assembly 100 comprises an illumination device 102, an envelope 104 and a light-processing layer 106. In addition, the light assembly 100 further includes two electrode sets 108 respectively disposed on two opposite distal ends of the envelope 104. Each electrode set comprises at least one electrode (not shown) disposed therein. In this case, each of the electrode sets 108 has one electrode disposed therein, and each electrode is electrically connected to the illumination device 102. In other example, the electrode set 108 may have two electrodes disposed therein. The electrodes may drive the illumination device 102 disposed in the envelope 104 by use of an external power source (not shown) so that the illumination device 102 emits a light. Moreover, the electrode sets 108 may support the illumination device 102 and thus maintain the illumination device 102 in position. Also, the electrode sets 108 may serve to seal the light assembly 100. Alternatively, additional sealing members (not shown) may be used to seal the light assembly 100. Said sealing members may be metal caps, plastic caps or other suitable sealants. Generally, the wavelength-converting layer may alter the wavelength composition of the light emitted from the illumination device 102; whereas the diffusion layer may diffuse the light emitted from the illumination device 102 so that the light is distributed uniformly along the periphery of the envelope. The light processed by the light-processing layer 106 would pass the light-transmissive envelope 104 to provide illumination.
According to embodiments of the present invention, the light-processing layer 106 may be a wavelength-converting layer, a diffusion layer, or a combination thereof. Said light-processing layer 106 may be a single layer, or consist of multiple layers.
When the light-processing layer 106 is a single layer, the light-processing layer 106 may be a wavelength-converting layer or a diffusion layer. In some embodiments, the light-processing layer 106 is a single layer but possess both the abilities to alter the wavelength composition and provide uniform distribution of the light. For example, in some cases, the wavelength-converting layer itself my posses the ability to diffuse the light. Similarly, in some cases, the diffusion layer itself may possess the ability to alter the wavelength composition of the light.
Alternatively, in some other embodiments, the light-processing layer 106 may consist of multiple layers. For example, the light-processing layer 106 may have a wavelength-converting layer and a diffusion layer disposed sequentially on the inner surface of the envelope 104. Of course, the order or sequence of said two layers on the envelope 104 is not limited to the described manner and may be swapped in some examples. In some examples, the light-processing layer 106 may consist of more than two layers.
Illustrative examples of the wavelength-converting layer include, but are not limited to, a light sensitive layer, a phosphor layer, a photoluminescent layer, a quantum dot layer, a quantum line layer, a quantum well layer, and a combination thereof. Specifically, said phosphor layer may be made of any suitable phosphor powders, more particularly, the phosphor powders having high color-rendering property. For example, the phosphor powders having high color-rendering property can be hydrolyzed colloid reaction (HCR) phosphor powders. Main composition of the HCR phosphor powders comprises red phosphor powders having a formula of Y(P,V)O₄:Eu, green phosphor powders having a formula of BaMgAl₁₀O₁₇:Eu,Mn or Zn₂SiO₄:Mn, and blue phosphor powders having a formula of Sr₅(PO₄)₃CI:Eu.
Generally, the diffusion layer may include a plurality of diffusive particles dispersed therein. Illustrative examples of the diffusive particle may include, but are not limited to phosphor particles, polystyrene (PS) particles and poly(methyl methacrylate) (PMMA) particles.
According to various embodiments of the present invention, the illumination device 102 may be an ultraviolet lamp, a CCFL, an LED or a UV LED. In addition, the illumination device 102 may or may not have mercury contained therein. Regarding the shape of the illumination device 102, it can be any suitable shape including, but not limited to, a prism-shape, a cylinder-shape, a U-shape, a round-shape, and a spiral-shape. When LEDs or UV LEDs are used as the illumination device 102, the LEDs or UV LEDs may be arranged in such a way to provide ideal illumination quality. The number of the illumination device 102 is not subjected to any particular limitation; rather, the number may be determined depending on the size of the envelope 104 and/or the size of the illumination device 102. Specifically, the number of the illumination device 102 may be one or more.
In some embodiments, another wavelength-converting layer and/or another diffusion layer may be formed on the outer surface of the illumination device 102 to assist or enhance the function of the light-processing layer 106.
According to various embodiments of this invention, the envelope 104 may be made of glass or thermoplastic materials. Illustrative examples of the thermoplastic materials include, but are not limited to, poly(methyl methacrylate) (PMMA), polystyrene (PS), methyl methacrylate-co-styrene (MS), polycarbonate, (PC), polyethylene terephthalate (PET), or polyimide.
In some embodiments, diffusive particles mentioned-above may be added into the thermoplastic materials during the manufacture of the envelope 104. As such, the envelope 104 thus prepared may itself possess the ability to diffuse the light to assist or enhance the function of the light-processing layer 106.
According to the principles and spirits of the present invention, the envelope 104 may have any suitable shape. For example, in some embodiments, the envelope 104 may have a prism-shape, and the prism-shaped envelope 104 may have a cross-section that is circular, elliptic or polygonal (i.e., triangular, quadrangular, pentagonal, or polygons having more line segments) in shape. In some embodiments, the envelope 104 may have a shape of a light tube or a light bulb. In some embodiments, the shape and size of the envelope 104 are identical to those of the commercially available light tubes or light bulbs, and hence the light assembly 100 may be fitted into the light sockets used to accommodate those commercial light tubes or light bulbs. It is well known that the commercially available light tubes or light bulbs have various sizes and shapes, and the specifications thereof are easily attainable and thus are not elaborated herein.
After reading the above paragraphs, those with ordinary skill in the art would appreciate that the features concerning the species, materials, shapes and quantities of the illumination device 102, the envelope 104, and the light-processing layer 106 may be combined to obtain a variety of light assemblies. Illustrative examples of light assemblies are described hereinafter in connection with appended drawings.
FIG. 2A is a cross-sectional diagram illustrating a light assembly 200 according to another embodiment of the present invention. The light assembly 200 may be used in a lighting apparatus or a backlight module. In the example shown in FIG. 2A, three cylindrical ultraviolet lamps 202 are used as the illumination device, and a wavelength-converting layer 216 is disposed on the inner surface of the envelope 204 so as to convert the UV light emitted from the ultraviolet lamps 206 into visible light.
The wavelength-converting layer 216 may be any one of the above-mentioned wavelength-converting layers. As one example, the wavelength-converting layer 216 may be a phosphor layer, such as a phosphor layer made of phosphor powders with high color-rendering property.
In this embodiment, the envelope 204 is made of a thermoplastic material such as PET. In manufacture, phosphor powders may be coated onto a surface of a PET sheet so as to form a wavelength-converting layer 216 thereon. Afterward, the PET sheet is rolled into a hollow tube in such a way that the wavelength-converting layer 216 is located on an inner surface thereof.
As shown in FIG. 2A, the envelope 204 has a cross-section that is elliptic in shape. In this case, said three ultraviolet lamps 202 are arranged on the long axis "L" of the elliptic envelope 204 in order to achieve optimal illumination efficiency. Said light assembly 200 having a cross-section that is elliptic in shape is particularly suitable to be used as the light source of the backlight modules. However, the shape shown in FIG. 2A is only an example, and the cross-sectional shape of the envelope 204 may be chosen depending on the design needs. In addition, ultraviolet lamp 202 may have other shape other than the cylindrical shape shown in FIG. 2A.
One feature of the light assembly 200 lies in that the wavelength-converting layer 216 at the UV lamps 202 are separately disposed, so that the UV light emitted from the UV lamps 202 must first pass through the body (usually made of the glass) of the UV lamps 202 before contacting the wavelength-converting layer 216.
In contrast, the phosphor layer (wavelength-converting layer) of conventional fluorescent light tube is disposed on the inner surface of the fluorescent light tube. In this case, the plasma formed during the illumination process of the fluorescent light tube may damage the crystal structure of the phosphor powders of the phosphor layer and thereby resulting in lattice defects therein and thus decreasing the luminance of the light emitted from the phosphor powders. In addition, the mercury vapor contained in conventional fluorescent light tube is excited to emit ultraviolet light having wavelengths at about 253.7 nm and about 185 nm. Under high operating temperature, the phosphor powders of the phosphor layer of the conventional fluorescent light tube may absorb the UV light at a wavelength of about 185 nm and thereby resulting in color centers therein. As a result, the wavelength composition and the color of the light emitted from the phosphor powders having color centers are different from those of the undamaged phosphor powders. Also, the formation of color centers would lower the luminance of the light emitted from the phosphor powders. Such problems would be even more serious for the fluorescent light tubes employing phosphor powders having high color-rendering index (i.e., those having a CRI equal to or greater than 90%), wherein a service life thereof is usually less than half of that of a T5 light tube.
In view of the forgoing, it is appreciated that by separately disposing the wavelength-converting layer and the source of the ultraviolet light according to the principles and spirits of the present invention, it is possible to effectively avoid said problems in the conventional fluorescent light tube where the phosphor layer are in direct contact with the plasma and the ultraviolet light. In addition, the body of the ultraviolet lamp is usually made of glass, which would absorb most of the 185 nm-UV light passing therethrough; this may further avoid the formation of color centers of the phosphor powders of the wavelength-converting layer.
Therefore, in the light assembly according to embodiments of the present invention, the degradation rate of the phosphor powders, especially the phosphor powders with high color-rendering property, would be substantially decreased. As such, as compared with conventional fluorescent light tube with high CRI, the service life of the light assembly according to embodiments of the present invention is extended so that it is substantially equal to or longer than the service life of T5 fluorescent lamps.
Optionally, the interior space of the envelope 204 is substantially evacuated such that the light assembly 200 is more suitable to be used in environments having low working temperatures, such as at about 0°C. As will occur to those with ordinary skill in the art, the luminance of light emitted from the conventional fluorescent light assembly would be decreased as the working temperature is lowered. The luminance of a fluorescent light assembly at temperature below 0°C is less than half of the luminance of the same fluorescent light assembly at about 30°C. Therefore, by substantially evacuating the interior space defined by the envelope 204 within the light assembly 200, the heat (or the temperature) of the ambient environment is less likely to be transferred to the interior of the light assembly 200. In this way, as compared with the light assembly not being evacuated, the luminance variation of the light assembly of this embodiment under different ambient temperatures is relatively small. As such, the light assembly according to this embodiment is suitable to be used in an environment with low working temperature.
FIG. 2B is a cross-sectional diagram illustrating a light assembly 250 according to another embodiment of the present invention. In this example, two ultraviolet lamps 202 are used as the illumination device and a diffusion layer 218 (as a light-processing layer) is disposed on the inner surface of the envelope 204. In addition, a phosphor layer 216 is disposed on the outer surface of the ultraviolet lamps 202, so as to convert the UV light emitted from the ultraviolet lamps 202 into visible light. As shown in FIG. 2B, the shape of the envelope 204 is cylindrical which is identical to that of commercially available fluorescent light tubes, and thus, the light assembly 250 may be fitted into conventional lamp sockets.
Similar to the light assembly 200, the light assembly 250 is featured in that the phosphor layer for converting the wavelength composition of the UV light and the source of the UV light are disposed separately. In addition, the diffusion layer 218 disposed on the inner surface of the light assembly 250 may provide uniform light distribution along the periphery of the envelope.
In alternative embodiments, the phosphor layer 216 may be disposed on an inner surface (i.e., the surface facing the interior of the light assembly) of the diffusion layer 218, or alternatively, the phosphor layer 216 may be sandwiched between the diffusion layer 218 and the envelope 204.
FIG. 3A is a cross-sectional diagram illustrating a light assembly 300 according to another embodiment of the present invention. In this example, two cylindrical CCFLs 302 are used as illumination device, and a diffusion layer 318 is disposed on an inner surface of the envelope 304 to diffusive the light emitted from the CCFLs 302 so as to provide a uniform light distribution along the periphery of the envelope 304. In this example, the materials of the envelope 304 and the diffusion layer 318 may be any one of the materials mentioned above.
FIG. 3B is an exploded view illustrating a light assembly 350 according to another embodiment of the present invention. In this example, a U-shaped CCFL 352 is used as the illumination device, and a diffusion layer 318 is disposed on an inner surface of the tubular envelope 304 to diffusive the light emitted from the CCFLs 352 so as to provide a uniform light distribution along the periphery of the envelope 304. As shown in FIG. 3B, an electrode set 308 having a pair of electrodes (not shown) therein is disposed on one distal end of the envelope 304. The CCFL 352 is electrically connected to and driven by the electrode set 308 to emit light. In this case, a sealing member 310 is disposed on the other distal end of the envelope 304. The sealing member 310 has a support 312 disposed thereon to hold the CCFL 352 in position. According to the spirits of the present invention, the shapes and sizes of the electrode set 308 and the sealing member 310 may be identical to those of the conventional light tubes so that the light assembly 350 may be fitted into conventional light sockets. In this embodiment, the materials of the envelope 304 and the diffusion layer 318 may be any one of the materials mentioned above.
FIG. 3C is a schematic diagram illustrating a light assembly 380 according to another embodiment of the present invention. In this example, a U-shaped CCFL 352 is used as the illumination device, the envelope 384 has a bulb shape, and a diffusion layer 318 is disposed on an inner surface of the envelope 384 to diffusive the light emitted from the CCFLs 352 so as to provide a uniform light distribution along the periphery of the envelope 384. In addition, as shown inFIG. 3C, an electrode set 388 having a pair of electrodes (not shown) therein is disposed at an opening of the bulb-shaped envelope 384. The CCFL 352 is electrically connected to and driven by the electrode set 388 to emit the light. According to the spirits of the present invention, the shape and size of the electrode set 388 may be identical to those of the conventional light tubes so that the light assembly 380 may be fitted into conventional light sockets. In various embodiments of the present invention, the CCFL may have other shapes such as helical, annular or cylindrical.
In the examples shown in Figs. 3A to 3C, since the surface area of the envelope is greater than that of a single CCFL, the diffusion layer disposed on the inner surface of the envelope may broaden the illumination area of the CCFL and diffusive the light.
Moreover, another diffusion layer (not shown) may be disposed on the outer surface of the CCFL 302/352 to assist or enhance the function of the diffusion layer 318. Said another diffusion layer may include a plurality of diffusive particles described above, and the material of this diffusion layer may be the same as or different from that of the diffusion layer 318.
FIG. 4 is a schematic diagram illustrating a light assembly 400 according to another embodiment of the present invention. In this example, a plurality of LEDs or UV LEDs are used as the illumination devices 402, the envelope 404 has a shape of a light bulb, and a light-processing layer 406 is disposed on an inner surface of the envelope 404. The materials of the envelope 404 and the light-processing layer 406 may be any one of the materials described above. In addition, as shown in FIG. 4, an electrode set 408 having a pair of electrodes (not shown) therein is disposed at an opening of the bulb-shaped envelope 404. The illumination devices 402 are electrically connected to and driven by the electrode set 408 to emit the light. According to the spirits of the present invention, the shape and size of the electrode set 408 may be identical to those of the conventional light tubes so that the light assembly 400 may be fitted into conventional light sockets.
In some embodiments, when LEDs are used as the illumination devices 402, the light-processing layer 406 may be a diffusion layer for distributing the light emitted from the LEDs.
In some other embodiments, when UV LEDs are used as the illumination devices 402, the light-processing layer 406 may be a wavelength-converting layer for converting the UV light emitted from the UV LEDs into visible light. In some of the above mentioned embodiments, the wavelength-converting layer or the envelope 404 per se may have the ability to diffuse the light; while in some other embodiments, a diffusion layer (not shown) may be sandwiched between the wavelength-converting layer and the envelope 404 to diffuse the light.
In another aspect, the present invention is directed to a light assembly. The light assembly comprises at least one illumination device, an envelope, an electrode set, and a wavelength-converting layer and/or a diffusion layer. The illumination device is operable to emit a light. The envelope encircles the illumination device and is light-transmissive per se. The wavelength-converting layer and/or the diffusion layer may be disposed on an inner surface of the envelope. The electrode set is disposed on one distal end of the envelope and electrically connected to the illumination device.
In some embodiments, only one of the wavelength-converting layer and the diffusion layer is disposed on the inner surface of the envelope. In some other embodiments, the envelope may have both of the wavelength-converting layer and the diffusion layer disposed on the inner surface thereof.
According to various embodiments of the present invention, the illumination device may be an ultraviolet lamp, a CCFL, an LED or a UV LED. According to various embodiments of the present invention, the envelope may have a shape of a light tube or a light bulb. The wavelength-converting layer and the diffusion layer may be any one of the materials described above.
The electrode set may also be used to hold the illumination device in position. In some embodiments, the shape and size of the electrode set is conformed to one of the specifications of existing light sockets so that the light assembly according to embodiments of the present invention may be directly fitted into these light sockets.
It is apparent form the above description that the application of the light assemblies according to various embodiments of the present invention provides at least one of the following advantages:

(1) Avoiding the formation of crystal defects and color centers of the phosphor material, and hence extending the service life of both the phosphor material and the light assembly;
(2) Employing illumination device (such as CCFL, ultraviolet lamp, LED, and UV LED) that is compact in size, low in power consumption, and high in illumination efficiency in conjunction with an envelope having relatively large surface area, so as to broaden the illumination area of the illumination device and to diffusive the light by a light-processing layer disposed on an inner surface of the envelope;
(3) Reducing the glare of the light assembly;
(4) The size and shape of the envelope of the light assembly may be identical or similar to those of the conventional light assemblies in conjunction with the electrode set and/or sealing member conformed with existing light sockets so that the light assembly can be directly installed in the existing light sockets;
(5) The envelope according to the embodiments of the present invention can be reused, and further, the envelope itself may be made of or made from a recycled item which makes the light assembly friendly to the environment and low in manufacturing cost.

It will be understood that the above description of embodiments is given by way of example only and that various modifications may be made by those with ordinary skill in the art. The above specification, examples and data provide a complete description of the structure and use of exemplary embodiments of the invention. Although various embodiments of the invention have been described above with a certain degree of particularity, or with reference to one or more individual embodiments, those with ordinary skill in the art could make numerous alterations to the disclosed embodiments without departing from the spirit or scope of this invention.

Claims

A light assembly, comprising:
at least one illumination device being operable to emit a light;

an envelope encircling the illumination device, wherein the envelope is light-transmissive; and

a light-processing layer disposed on an inner surface of the envelope, wherein the light-processing layer is selected from a group consisting of a wavelength-converting layer, a diffusion layer, and a combination thereof.
The light assembly of claim 1, further comprising an electrode set disposed at one distal end of the envelope and electrically connected to the illumination device.
The light assembly of claim 1, wherein the illumination device is an ultraviolet lamp, cold cathode fluorescent lamp, a light emitting diode or an ultraviolet light emitting diode.
The light assembly of claim 3, wherein the illumination device is an ultraviolet lamp or an ultraviolet light emitting diode, and the light-processing layer comprises the wavelength-converting layer.
The light assembly of claim 3, wherein the illumination device is an ultraviolet lamp or an ultraviolet light emitting diode, the light-processing layer is the diffusion layer, and the illumination device further comprises another wavelength-converting layer disposed on an outer surface thereof.
The light assembly of claim 1, wherein the illumination device has a shape of a prism, a cylinder, a U-shape, a round-shape, or a spiral-shape.
The light assembly of claim 1, wherein the envelope has a shape of a light tube or a light bulb.
The light assembly of claim 1, wherein the wavelength-converting layer is a light sensitive layer, a phosphor layer, a photoluminescent layer, a quantum dot layer, a quantum line layer, or a quantum well layer.
The light assembly of claim 1, wherein the diffusion layer comprises at least one material selected from the group consisting of phosphor particles, polystyrene particles and poly(methyl methacrylate) particles.
A light assembly, comprising:
at least one illumination device being operable to emit a light, wherein the illumination device is an ultraviolet lamp, cold cathode fluorescent lamp, a light emitting diode or an ultraviolet light emitting diode;

an envelope encircling the illumination device, wherein the envelope is light-transmissive and has a shape of a light tube or a light bulb;

a wavelength-converting layer and/or a diffusion layer disposed on an inner surface of the envelope; and

an electrode set disposed on one distal end of the envelope and electrically connected to the illumination device.