Abstract:
An exemplary air cleaning device includes a roller, a photo-catalyst layer and a light source. The roller includes a base and a plurality of fins installed on the base. The roller is movable to cause an air to flow. The photo-catalyst layer is formed on the fins. The light source is disposed facing toward the roller for irradiating the photo-catalyst layer to cause a photocatalytic reaction thus cleaning the air flowing therethrough.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present disclosure generally relates to an air cleaning device. 
         [0003]    2. Discussion of Related Art 
         [0004]    Air pollution has long been recognized as a threat to human health as well as to earth&#39;s ecosystems. In such, air cleaning devices are widely used to improve air quality of the environment. 
         [0005]    Most conventional air cleaning devices use activated carbon or ozone to filter and absorb contaminants and sterilize microbes in the air. Ozone has strong oxidative function, it can oxidize organic pollutant in the air immediately and decomposed into vitriol and nitric acid. But vitriol and nitric acid are also harmful to the human health and the environment. Also, activated carbon may loose its effect (e.g. absorbing efficiency) if it is exposure to air for a long time. 
         [0006]    What is needed, therefore, is an improved air cleaning device which can overcome the above shortcomings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    Many aspects of the present air cleaning device can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present air cleaning device. Moreover, in the drawings, like reference numerals designate corresponding parts throughout certain views. 
           [0008]      FIG. 1  is a schematic view of air cleaning device, according to a first exemplary embodiment. 
           [0009]      FIG. 2  is a schematic enlarged view of a circled portion of  FIG. 1 . 
           [0010]      FIG. 3  is a schematic view of air cleaning device, according to a second exemplary embodiment. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0011]    Reference will now be made to the drawings to describe embodiments of the present air cleaning device, in detail. 
         [0012]    Referring to  FIGS. 1 and 2 , an air cleaning device  100 , according to a first embodiment, includes a roller  101 , a photo-catalyst layer  102  and a light source  103 . 
         [0013]    The roller  101  comprising a columnar base  1010  and a plurality of fins  1011  installed on the base  1010 . The base  1010  has a central axis OO′. The fins  1011  extend outwards from the roller  101  and are inclined in a direction opposite to the rotational direction of the roller  101 . In the present embodiment, each of the fins  1011  extend at an acute angle measured clockwise from an imaginary line tangential to the circumference of the roller  101 . In an exemplary embodiment, the base  1010  is integrally formed with the fins  1011 . Each of the fins  1011  has an external surface  1013 , and the base  1010  has a discontinuous external surface  1012  between every two adjacent fins  1011 . The roller  101  is capable of rotating manually or automatically and the fins  1011  rotate with the roller  101  to create an airflow. The photo-catalyst layer  102  is formed on the external surface  1012  of the base  1010  and the external surfaces  1013  of the fins  1011 . The photo-catalyst layer  102  contains titanium dioxide (TiO 2 ), tin oxide (SnO 2 ), zinc oxide (ZnO), tungsten oxide (WO 3 ), iron oxide (Fe 2 O 3 ), SeTiO 3 , cadmium selenide (CdSe), KTaO 3 , cadmium sulfide (CdS) or niobium oxide (Nb 2 O 5 ). Generally, the photo-catalyst layer  102  contains a material selected from the group consisting of chromium, vanadium, carbon, nitrogen and sulfur and any combination thereof. When airflow is generated, the photo-catalyst layer  102  can initiate photocatalytic reactions with organic contaminants contained in the air, excited by the light from the light source  103 . Therefore, the organic contaminants can be oxidized and decomposed into carbon dioxide (CO 2 ) and water (H 2 O). It can be understood that the photo-catalyst layer  102  may be only formed on the external surfaces  1013  of the fins  1011 . 
         [0014]    The light source  103  comprising a substrate  1031  and a plurality of light emitting elements  1032 . The light emitting elements  1032  are arranged on the substrate  1031  and facing toward external surfaces  1013  of the fins  1011 , therefore, light emitted from the light emitting elements  1032  can irradiate the photo-catalyst layer  102 . The light emitting elements  1032  are selected from the group consisting of a light emitting diode chip, a light emitting diode and a light emitting diode module. In the present embodiment, the light emitting elements  1032  are white light emitting diodes and can be used for illuminating. 
         [0015]    The air cleaning device  100  further comprises a drive module  104 . The drive module  104  is mechanically connected with the base  1010  of the roller  101 . The drive module  104  is configured for driving the roller  101  rotates around the central axis OO′. In general, the drive module  104  is a motor. 
         [0016]    In the present embodiment, the drive module  104  drives the roller  101  rotate and creates airflow with rotating of the fins  1011 . Thus, an inlet and an outlet are not needed. Additionally, the photo-catalyst layer  102  is formed on the external surfaces  1013  of the fins  1011 , the area of the photo-catalyst layer  102  is enlarged, therefore, the efficiency of the air cleaning device  100  is improved. 
         [0017]    Referring to  FIG. 3 , an air cleaning device  200 , in accordance with a second embodiment. The air cleaning device  200  is similar to the air cleaning device  100  except that an ultraviolet (UV) light source  2033  and a light pervious board  205  are included. 
         [0018]    The light pervious board  205  is arranged between a light source  203  and a roller  201 . A plurality of through holes  2051  are formed in the light pervious board  205 . The light pervious board  205  is doped with a phosphors layer thereon. The material of phosphors can absorb UV light and change the wavelength of UV light to visual light. 
         [0019]    The light source  203  includes a substrate  2031  and an UV light source  2033 . The UV light source  2033  is arranged on the substrate  2031  and opposite to the light pervious board  205 . Preferably, the UV light source  2033  is a UV light emitting diode. Additionally, there can be more than one UV light source  2033  arranged on the substrate  2031 . 
         [0020]    A part of UV light form the UV light source  2033  can pass the through holes  2051  to irradiate the photo-catalyst layer  202 , and the photo-catalyst layer  202  initiate photocatalytic reactions with organic contaminants adsorbed in the air and decomposed into carbon dioxide (CO 2 ) and water (H 2 O). 
         [0021]    Other part of UV light form the UV light source  2033  irradiate to the light pervious board  205 , and the phosphors in the light pervious board  205  can absorb UV light and change the wavelength of UV light to visual light. The visual light not only can be used to excite the photo-catalyst layer  202  but also can be used to illuminate. 
         [0022]    Preferably, the light pervious board  205  is movable relative to the light source  203  by manually or automatically. Therefore, when the air cleaning device  200  is only used for cleaning air, the light pervious board  205  is moved away from the light path of the UV light source  2033 , so that all UV light emitted from the UV light source  2033  can irradiate the photo-catalysis layer  202  and improve efficiency of the air cleaning device  200 . 
         [0023]    The photocatalytic reactions of the photo-catalyst layer  202  with the UV light is much faster than that of the visual light, therefore, the efficiency of the air cleaning device  200  is improved. Additionally, the air cleaning device  200  includes a light pervious board  205  which has phosphor therein, the phosphor can absorb part of the UV light to limit excess UV light that is harmful to human health. 
         [0024]    Advantageously, the air cleaning device can be used for illumination. 
         [0025]    It is to be understood, however, that even though numerous characteristics and advantages have been set forth in the foregoing description of embodiments, together with details of the structures and functions of the embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.