Patent Publication Number: US-2015076453-A1

Title: Ultraviolet organic light-emitting apparatus

Description:
FIELD OF THE INVENTION 
     The present invention relates to an ultraviolet (UV) light field, and more particularly to a UV organic light-emitting apparatus for emitting UV light. 
     BACKGROUND OF THE INVENTION 
     Ultraviolet (UV) light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays. It is named because the spectrum consists of electromagnetic waves with frequencies higher than those that humans identify as the colour violet. 
     UV light is found in sunlight and can be emitted by electric arcs and specialized lights such as black lights. It can cause chemical reactions, and causes many substances to glow or fluoresce. Although ultraviolet radiation is invisible to the human eye, most people are aware of the effects of UV through sunburn. However, the UV spectrum has many effects, both beneficial and damaging, to human health. For example, UV light is applicable to medical treatments. 
     However, a conventional UV light lamp, such as a mercury lamp, may have poisonous materials or gas and is breakable. Moreover, an irradiation area of the conventional UV light lamp is limited, and the conventional UV light lamp is difficult for portability. 
     As a result, it is necessary to provide a UV organic light-emitting apparatus to solve the problems existing in conventional technologies such as above-mentioned. 
     SUMMARY OF THE INVENTION 
     The present invention provides a UV organic light-emitting apparatus to solve the problems existing in the conventional UV lamp. 
     A primary object of the present invention is to provide a UV organic light-emitting apparatus, and the UV organic light-emitting apparatus comprises: a UV organic light-emitting device comprising: a UV organic material layer for emitting a UV light; a first electrode formed at one side of the UV organic material layer; and a second electrode formed at another opposite side of the UV organic material layer; and a passivation layer disposed at a light emitting side of the UV organic light-emitting device, wherein the passivation layer is made of a transparent material showing a weak absorption in a UV spectral region. 
     A secondary object of the present invention is to provide a UV organic light-emitting apparatus, and the UV organic light-emitting apparatus comprises: a UV organic light-emitting device comprising: a UV organic material layer for emitting a UV light, wherein a band gap of a material of the UV organic material layer is greater than 3.1 eV; a first electrode formed at one side of the UV organic material layer; and a second electrode formed at another opposite side of the UV organic material layer; and a passivation layer disposed at a light emitting side of the UV organic light-emitting device, wherein the passivation layer is made of a transparent material showing a weak absorption in a UV spectral region, and an absorptivity of the transparent material to the UV light is less than an absorptivity of a glass substrate to the UV light. 
     In one embodiment of the present invention, the passivation layer is substrate structure, and the first electrode, the UV organic material layer and the second electrode are formed on the passivation layer in sequence. 
     In one embodiment of the present invention, the UV organic material layer is made of a UV organic material containing carbazole, fluorine, triphenylamine or quinquephenyl. 
     In one embodiment of the present invention, a band gap of a material of the UV organic material layer is greater than 3.1 eV. 
     In one embodiment of the present invention, the band gap of the material of the UV organic material layer is in a range of 3.1 eV to 3.9 eV. 
     In one embodiment of the present invention, the passivation layer is made of a quartz glass. 
     In one embodiment of the present invention, the passivation layer is made of Poly(methyl methacrylate). 
     In one embodiment of the present invention, the UV organic light-emitting device further comprises a substrate, and the first electrode, the UV organic material layer and the second electrode are stacked on the substrate in sequence. 
     In one embodiment of the present invention, a starting voltage of the UV organic light-emitting apparatus is lower than 10 V. 
     In one embodiment of the present invention, an absorptivity of the transparent material to the UV light is less than an absorptivity of a glass substrate to the UV light. 
     In comparison to the conventional UV lamp, the UV organic light-emitting apparatus of the present invention can have less poisonous materials or gas for reducing contamination. Moreover, the UV organic light-emitting apparatus of the present invention can mitigate the breakable problem and the limited irradiation area problem of the conventional UV lamp. In addition, the substrate of the UV organic light-emitting apparatus can be a flexible substrate, and thus it is allowable to be a portable apparatus, thereby improving the practicality and convenience thereof. Furthermore, the UV organic light-emitting apparatus can have a lower starting voltage, thereby having a higher power conversion efficiency. 
     The structure and the technical means adopted by the present invention to achieve the above-mentioned and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings: 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram showing a UV organic light-emitting apparatus according to one embodiment of the present invention; 
         FIG. 2  is a specific diagram showing the UV organic light-emitting apparatus according to one embodiment of the present invention; 
         FIG. 3  is a schematic diagram showing a UV organic light-emitting apparatus according to another embodiment of the present invention; and 
         FIG. 4  is a specific diagram showing the UV organic light-emitting apparatus according to another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following embodiments are exemplified by referring to the accompanying drawings, for describing specific embodiments implemented by the present invention. Furthermore, directional terms described by the present invention, such as upper, lower, front, back, left, right, inner, outer, side and etc., are only directions by referring to the accompanying drawings, and thus the used directional terms are used to describe and understand the present invention, but the present invention is not limited thereto. 
     In the drawings, like reference numerals indicate like components or items. 
     Referring to  FIG. 1 , a schematic diagram showing a UV organic light-emitting apparatus according to one embodiment of the present invention is illustrated. The UV organic light-emitting apparatus  100  can cat as a UV light source or a UV lamp. The UV organic light-emitting apparatus  100  can comprises a UV organic light-emitting device  110  and a passivation layer  120 . The UV organic light-emitting device  110  is configured to emit a UV light having a wavelength which is less than 400 nm, such as in a range of 280 nm to 400 nm. The passivation layer  120  is disposed at a light emitting side of the UV organic light-emitting device  110  for protecting the UV organic light-emitting device  110 , wherein the passivation layer  120  is made of a transparent material showing a weak absorption in a UV spectral region. 
     Referring to  FIG. 2 , a specific diagram showing the UV organic light-emitting apparatus according to one embodiment of the present invention is illustrated. The UV organic light-emitting device  110  can comprise a first electrode  111 , a UV organic material layer  112  and a second electrode  113 . The first electrode  111  is formed at one side of the UV organic material layer  112  to act as an anode, and the second electrode  113  is formed at another opposite side of the UV organic material layer  112  to act as a cathode. In the present embodiment, the UV organic light-emitting device  110  can be a bottom-emitting type organic light-emitting device, and the passivation layer  120  can be a substrate structure. At this time, the first electrode  111 , the UV organic material layer  112  and the second electrode  113  are formed on the passivation layer  120  in sequence. The first electrode  111  is disposed close to the light emitting side of the UV organic light-emitting device  110 . The first electrode  111  is preferably made of a transparent conductive material, such as ITO, IZO, AZO, GZO, TCO or ZnO, for allowing the UV light to pass through. The second electrode  113  may be made of Ag, Li, Mg, Al or any alloy thereof. The UV organic material layer  112  is configured to emit the UV light, and the material of the UV organic material layer  112  can have a wide band gap, and may be a UV organic material containing carbazole, fluorine, triphenylamine, quinquephenyl and the like, wherein a band gap of the UV organic material of the UV organic material layer  112  is preferably greater than 3.1 eV, such as in a range of 3.1 eV to 3.9 eV. In that manner, a wavelength of the UV light emitted by the UV organic material layer  112  can be less than 400 nm. 
     For example, in the UV organic material layer  112 , the UV organic material containing carbazole has a band gap of about 3.25 eV and a spectral peak at about 394 nm. Moreover, for example, in the UV organic material layer  112 , the UV organic material containing quinquephenyl has a band gap of about 3.48 eV and a spectral peak at about 310 nm. 
     In one embodiment, the UV organic material layer  112  may comprise a hole injection layer, a hole transportation layer, an emission layer, an electron transportation layer and an electron injection layer stacked on the first electrode  111  in sequence for improving a light emitting efficiency of the UV organic material layer  112 . 
     In this embodiment, referring to  FIG. 2  again, the passivation layer  120  is disposed at an outer side of the first electrode  111 . The passivation layer  120  can be made of a transparent material showing a weak absorption in a UV spectral region, such as a quartz glass or an organic material (for example Poly(methyl methacrylate), PMMA), and an absorptivity of the transparent material to the UV light is less than an absorptivity of a glass substrate to the UV light, so as to prevent most of the UV light emitted by the UV organic material layer  112  from being absorbed by the passivation layer  120 . Therefore, the passivation layer  120  can protect the UV organic light-emitting device  110  from environmental damages, and can ensure the light emitting efficiency thereof. 
     Therefore, the UV organic light-emitting apparatus  100  can be configured to emit the UV light. In comparison with the conventional UV lamp, with the use of the UV organic light-emitting apparatus  100 , the use of poisonous materials or gas can be omitted or reduced to reduce contamination. Furthermore, the UV organic light-emitting apparatus  100  can act as a planar light source to mitigate the breakable problem, and can have a large irradiation area. In addition, the substrate (for example the passivation layer  120 ) of the UV organic light-emitting apparatus  100  can be a flexible substrate, and thus it is allowable to be a portable apparatus. 
     In this embodiment, a starting voltage of the UV organic light-emitting apparatus  100  can be lower than 10 V. Accordingly, in comparison with the conventional UV lamp, the UV organic light-emitting apparatus  100  of the present embodiment can have a lower energy consumption and a higher power conversion efficiency. 
     Referring to  FIG. 3 , a schematic diagram showing a UV organic light-emitting apparatus according to another embodiment of the present invention is illustrated. In another embodiment, the UV organic light-emitting device  210  can comprise a first electrode  211 , a UV organic material layer  212 , a second electrode  213  and a substrate  214 . In this embodiment, the UV organic light-emitting device  210  can be a top-emitting type organic light-emitting device, and the passivation layer  220  can cover the second electrode  213  of the UV organic light-emitting device  210 . At this time, the first electrode  211 , the UV organic material layer  212  and the second electrode  213  are stacked on the substrate  214  in sequence. The material of the first electrode  211  may be a high reflective metal, such as silver, silver oxide, gold, aluminum or any alloy thereof. The second electrode  213  is disposed close to the light emitting side of the UV organic light-emitting device  210 , and is preferably made of a transparent conductive material, such as ITO, IZO, AZO, GZO, TCO or ZnO, for allowing the UV light to pass through. The UV organic material layer  212  is configured to emit the UV light, and is preferably made of a material having a wide band gap. The substrate  214  may be a glass substrate, a flexible plastic substrate, a wafer substrate or a heat dissipation substrate for supporting the first electrode  211 , the UV organic material layer  212  and the second electrode  213 . The passivation layer  220  covers the second electrode  213  and protects the second electrode  213  from environmental damages. The passivation layer  220  can be made of a transparent material showing a weak absorption in the UV spectral region, such as quartz glass or organic material (for example PMMA), so as to prevent most of the UV light emitted by the UV organic material layer  212  from being absorbed by the passivation layer  220 . In this embodiment, an absorptivity of the passivation layer  220  to the UV light is less than the absorptivity of the glass substrate to the UV light. 
     Referring to  FIG. 4 , a specific diagram showing the UV organic light-emitting apparatus according to another embodiment of the present invention is illustrated. In one embodiment, the passivation layer  220  may be made of a composite material. At this time, the passivation layer  220  can comprise sub-passivation layers  221  and organic layers  222  which are stacked on the second electrode  213  in an alternating manner. The material of the sub-passivation layers  221  may be SiN x  and/or SiO x , and the organic layers  222  are configured to prevent the sub-passivation layers  221  from fragility, so as to enhance the structure of the passivation layer  220 . 
     As described above, the UV organic light-emitting apparatus of the present invention can be used for emitting the UV light. In comparison with the conventional UV lamp, the UV organic light-emitting apparatus of the present invention can have less poisonous materials or gas for reducing contamination. Moreover, the UV organic light-emitting apparatus of the present invention can mitigate the breakable problem and the limited irradiation area problem. In addition, the substrate of the UV organic light-emitting apparatus can be a flexible substrate, and thus it is allowable to be a portable apparatus, thereby improving the practicality and convenience thereof. Furthermore, the UV organic light-emitting apparatus can have a lower starting voltage, thereby having a higher power conversion efficiency. 
     The present invention has been described with a preferred embodiment thereof and it is understood that many changes and modifications to the described embodiment can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims.