Abstract:
A light emitting module includes a light-emitting unit, a wavelength converting element and an optical convergent element for partially or totally converting the wavelength of incident light. The light-emitting unit includes a light-emitting element which emits a first light, the wavelength converting element and an optical convergent element disposed in a light path of the first light from the light-emitting element, such that the first light is converted into a particular light at a specific area with a reduced beam diameter after passing through the optical convergent element and before entering the wavelength converting element.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims priority to Taiwan Application Serial Number 102105857, filed Feb. 20, 2013, which is herein incorporated by reference. 
       BACKGROUND 
       [0002]    1. Field of Invention 
         [0003]    The present invention relates to a light emitting module. More particularly, the present invention relates to a light-emitting module having an optical convergent element. 
         [0004]    2. Description of Related Art 
         [0005]    Light sources used in modern lighting devices normally includes incandescent light, halogen light, fluorescent light, cold cathode fluorescent lighting (CCFL), light emitting diode (LED) and so on. Once the light sources have been made, it is hard to modify their color temperature and color rendering. General incandescent light bulbs have good color temperature and color rendering, but suffer a relatively short lifetime and low luminous efficiency. Compare with incandescent lamps, halogen lamps have improved the shortcoming of lifetime and luminous efficiency, but have problems about high heat generation and ultraviolet. In addition, traditional lighting devices with the application of an incandescent principle have limitations of high heat generation, and fixed color temperature and color rendering after they leave the factory. As to the CCFL, it has problems about environment protection because containing mercury, and also has the problems about insufficient color temperature and color rendering. 
         [0006]    In recent years, the LED has the predominance of other traditional lighting sources because of its merits of small volume, long lifetime, short reaction time, and the environmental protection without contamination problem about e.g. thermal radiation, mercury and other toxic substance. Two approaches are used in the industry now to emit white LED light, in which one is to combine different wavelength emitting LED chips, and another is using wavelength division converting materials, like semiconductor, phosphor or dye, cooperate with a monochromatic light LED. 
         [0007]    However, the emergent LED lighting sources still cannot totally replace traditional lighting sources. The main reason is that the commercialized LED lighting production lacking of the feature to present consistent color temperature accurately, so that inevitably having color temperature differences between the productions. A remote phosphor technique has been provided to solve the non-consistent color temperature problem. However, because the usage of the phosphor in remote phosphor is more than traditional LED, using this technique on fluorescent tube need large area of phosphor, and made high raise in cost inevitably. 
       SUMMARY 
       [0008]    In this regard, one embodiment of the present invention provides a light emitting module, so as to mainly apply an optical convergence component to converge the light beams emitted by the light-emitting element in the light emitting module. As such, the required area phosphor is decreased. 
         [0009]    To reach the abovementioned purpose, according to one embodiment of the present invention, a light emitting module includes a light-emitting unit, an optical convergent element, and a wave converting element. The light-emitting unit includes a light-emitting element. In which the light-emitting element emits a first light in wavelength λ 1 , and the optical convergent element disposed in a light path of the first light from the light-emitting element, making the first light in wavelength λ 1  converge to a specific area. After passing through the optical convergent element, the first light becomes a second light in wavelength λ 1  of the specific area. The wave converting element is disposed in a light path of the second light from the optical convergent element, and the wave converting element having a wave converting material and an incident plane, making the second light in wavelength λ 1 , after entering the incident plane and the wavelength converting element, be converted to a third light in wavelength λ 2 . 
         [0010]    In some embodiments of the present invention, the light-emitting unit also have a reflecting element, surrounding the abovementioned light-emitting unit and directing the first light in the wavelength λ 1  emitted from the light-emitting element to be reflected first by the reflecting element, and then to enter the optical convergent element. 
         [0011]    In some embodiments of the present invention, the light emitting module, further including a diffusion element, disposed on the top of the emitting direction of the third light in wavelength λ 2 , to uniformly diffuse and receive the third light in wavelength λ 2 , which passing through the wavelength converting element. 
         [0012]    In some embodiments of the present invention, the area of the incident plane for the wavelength converting element, substantially equal to the specific area of the second light in the wavelength λ 1 , which comes from the optical convergent element. 
         [0013]    In some embodiments of the present invention, the wavelength converting element includes: a body; and at least one wavelength converting material, which is separated in the body in a uniform or patterned or laminar way. 
         [0014]    In some embodiments of the present invention, the wavelength converting material is one selected from the group consisting of phosphor, dye, pigments, quantum dots (QDs) and combinations thereof. 
         [0015]    In some embodiments of the present invention, the phosphor is a phosphor that is capable of emitting visible light; and base on one embodiment of the invention, a light color of the visible light emitted from the phosphor is one selected from the group consisting of red, green, blue and combinations thereof. 
         [0016]    In some embodiments of the present invention, the light-emitting element is a light emitting diode chip. According to one embodiment of the invention, the light emitting diode chip is an ultraviolet light chip or a blue light chip. 
         [0017]    In some embodiments of the present invention, the optical convergent element is a condensing lens. Following one embodiment of the invention, condensing lens can be one selected from the group consisting of a convex lens, spherical lens, hemispherical lens, spherocylinder lens, cylindrical lens, molded lens, Fresnel lens and combinations thereof. And in another embodiment of the invention, the convex lens is selected from the group consisting of plane-convex lens, double-convex lens, concave-convex lens and combinations thereof. 
         [0018]    In some embodiments of the present invention, the light emitting module further includes encapsulating glue, covering the abovementioned light-emitting element. 
         [0019]    By the abovementioned embodiments of the present invention, the area of the incident plane used on the wavelength converting element for lens can be reduced effectively. In other words, it can save the wavelength converting material effectively. 
         [0020]    It is to be understood that both the foregoing general description and the following detailed description are by examples, and are intended to provide further explanation of the invention as claimed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    The invention can be more fully understood by reading the following detailed description of the embodiment, with reference made to the accompanying drawings as follows: 
           [0022]      FIG. 1  is a schematic diagram of light emitting module; and 
           [0023]      FIG. 2  is a schematic diagram of light emitting module; and 
           [0024]      FIG. 3  is a schematic diagram of light emitting module; and 
           [0025]      FIG. 4A  is a schematic diagram of light emitting module using in a strip lamp; and 
           [0026]      FIG. 4B  is a schematic diagram of light emitting module using in a strip lamp according to one embodiment of this invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0027]    Reference will now be made in detail to the present embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts. 
         [0028]      FIG. 1  is a schematic diagram of light emitting module according to one embodiment of this invention. As shown in  FIG. 1 , the light emitting module of this embodiment includes a light-emitting unit, an optical convergent element  104  and a wavelength converting element  106 . In which, the light-emitting unit includes a light-emitting element  102 . The light-emitting element  102  emits a first light  103  with wavelength λ 1 , passing through an optical convergent element  104 , which disposed in a light path of the first light  103  from the light-emitting element  102 , making the first light  103  in wavelength λ 1  converge to a specific area, and the first light  104  becomes a second light  105  in wavelength λ 1 . The second light  105  emits from the optical convergent element  104 , irradiating on an incident plane of the wavelength converting element  106 . Having a wavelength converting material in the wavelength converting element  106  makes the second light  105  in wavelength λ 1 , after entering the incident plane and the wavelength converting element  106 , be converted to a third light  107  in wavelength λ 2 . 
         [0029]    According to one embodiment of the present invention, the light-emitting element  102  includes a light emitting diode chip, mounted on a substrate  108 . The surface of substrate  108 , which the light emitting diode chip mounted, can coat a retro-reflective material layer on it, or the substrate  108  is made by retro-reflective material. In which, the light emitting diode chip may be an ultraviolet light chip or a blue light chip. 
         [0030]    According to one embodiment of the present invention, the area of the incident plane on the wavelength converting element  106  , essentially equal to the specific area of the second light  105  in wavelength λ 1 , which comes from the optical convergent element  104 . 
         [0031]    According to one embodiment of the present invention, the wavelength converting element  106  includes a body and at least one wavelength converting material, which is separated in the body in a uniform or graphical or laminar way. 
         [0032]    According to one embodiment of the present invention, the light emitting module includes a diffusion element, which is disposed on the top of the emitting direction of the third light  107  in wavelength λ 2 , in order to diffuse, unify and receive the third light  107  in wavelength λ 2 , which passing through the wavelength converting element. 
         [0033]    According to one embodiment of the present invention, the optical convergent element  104  is a condensing lens. In some embodiments of the present invention, the condensing lens is selected from the group consisting of a convex lens, spherical lens, hemispherical lens, spherocylinder lens, cylindrical lens, molded lens, Fresnel lens and combinations thereof. In another embodiment, convex lens is selected from the group consisting of plane-convex lens, double-convex lens, concave-convex lens and combinations thereof. 
         [0034]      FIG. 2  depicts a schematic diagram of light emitting module according to one embodiment of this invention. As shown in  FIG. 2 , the light emitting module in the embodiment includes a light unit, an optical convergence element  204 , a reflecting element  209  and a wavelength converting element  206 . The light unit contains a light-emitting element  202 . The light-emitting element  202  emits a first light  203  in wavelength λ 1 . The first light  203  in wavelength λ 1  is first reflected by the reflecting element  209 , changing the optical pathway, and then passing through the optical convergence element  204 . After passing through the optical convergence element  204 , the first light  203  in wavelength λ 1  is converged to a specific area and becoming a second light  205  in wavelength λ 1 . The second light  205  is first emitted from the optical convergence element  204 , then irradiate on an incident plane of a wavelength converting element  206 , which includes a wavelength converting material, after passing through the wavelength converting element  206 , the second light  205  in wavelength λ 1  is converted to a third light  207  in wavelength λ 2 . 
         [0035]    According to one embodiment of the present invention, the light-emitting element  202  includes a light emitting diode chip, mounted on a substrate  208 . The surface of substrate  208 , which the light emitting diode chip mounted, can coat a retro-reflective material layer on it, or the substrate  208  is made by retro-reflective material. 
         [0036]    According to one embodiment of the present invention, the area of the incident plane on the wavelength converting element  206 , essentially equal to the specific area of the second light  205  in wavelength λ 1 , which comes from the optical convergent element  204 . 
         [0037]    According to one embodiment of the present invention, the wavelength converting element  206  includes a body and at least one wavelength converting material, which is separated in the body in a uniform or graphical or laminar way. 
         [0038]    According to one embodiment of the present invention, the light emitting module includes a diffusion element, which is disposed on the top of the emitting direction of the third light  207  in wavelength λ 2 , in order to diffuse, unify and receive the third light  207  in wavelength λ 2 , which passing through the wavelength converting element. 
         [0039]    According to one embodiment of the present invention, the optical convergent element  204  is a condensing lens. In some embodiments of the present invention, the condensing lens is selected from the group consisting of a convex lens, spherical lens, hemispherical lens, spherocylinder lens, cylindrical lens, molded lens, Fresnel lens and combinations thereof. In another embodiment, convex lens is selected from the group consisting of plane-convex lens, double-convex lens, concave-convex lens and combinations thereof. 
         [0040]      FIG. 3  depicts a schematic drawing of light emitting module according to one embodiment of this invention. As shown in  FIG. 3 , the light emitting module in the embodiment includes a light unit, an optical convergence lens array  304 , a reflecting substrate  308  and a wavelength converting element array  306 . In which, the light unit includes a light emitting diode chip array  302 . In one embodiment of the present invention, every light emitting diode chip array  302  includes encapsulating glue covering every light emitting diode chips. Refer to  FIG. 1  and  FIG. 2 , the light emitting diode chip array  302  emits first light in wavelength λ 1 , then the first light in wavelength λ 1  passing through the optical convergence lens array  304 . The first light is converged to a specific area and becoming a second light in wavelength λ 1 , after passing through the optical convergence lens array  304 . The second light is first emitted from the optical convergence lens array  304 , then irradiate on the incident plane of the wavelength converting element array  306 . 
         [0041]    Because the wavelength converting element array  306  includes a wavelength converting material, after entering the incident plane and passing through the wavelength converting element array  306 , the second light in wavelength λ 1  is converted to a third light in wavelength λ 2 . Then, the third light after being received and passing through wavelength converting element array  306 , entering a diffusion element  310  to diffuse and unify the third light. 
         [0042]      FIG. 4A  and  FIG. 4B  depict schematic diagrams of light emitting module using in a strip lamp according to one embodiment of this invention.  FIG. 4B  is a cross-sectional view of strip lamp  400  plane A in  FIG. 4A . 
         [0043]    As shown in  FIG. 4B , the strip lamp  400  includes a light-emitting unit, an optical convergent lens  404 , an optical reflecting element  408  and a strip-shape wavelength converting element  406 . Abovementioned light-emitting unit includes a plurality of light emitting diodes  402  arranged in lines. Refer to  FIG. 1  and  FIG. 2 , a plurality of light emitting diode chips emit first light, then the first light in wavelength λ 1  passing through the optical convergence lens  404 . The first light is converged to a specific area and becoming a second light in wavelength λ 1 , after passing through the optical convergence lens  404 . The optical convergence lens  404  is on the top of the light emitting diode chips, covering all the irradiation range with the emission angle of the light emitting diode chips  402 . For example, the emission angle of the light emitting diode chip  402  can be 120 degrees, and the optical convergence lens  404  can cover the irradiation range for at least 120 degree for the light emitting diode chip  402 . After that, the second light irradiate on the incident plane of the strip-shape wavelength converting element  406 , after being emitted from the optical convergence lens  404 . 
         [0044]    Because the strip-shape wavelength converting element  406  includes a wavelength converting material, after entering the incident plane and passing through the strip-shape wavelength converting element  406 , the second light in wavelength λ 1  is converted to a third light in wavelength λ 2 . Then, the third light after being received and passing through the strip-shape wavelength converting element  406 , entering a diffusion lens  409  to diffuse and unify the third light. 
         [0045]    In some embodiments, the light emitting diode chip  402  may be a light emitting diode chip which emits blue or ultraviolet light in wavelength λ 1 . The strip-shape wavelength converting element  406  can contain a wavelength converting material, which convert λ 1  to λ 2  , where λ 2  is larger than λ 1 . To be specific, the light emitting diode chip  402  emits a light having wavelength λ 1  (e.g., short wavelength light like ultraviolet light or blue light), which can excite the wavelength converting element, making the light having wavelength λ 1  (e.g., ultraviolet light or blue light) convert to a light having wavelength λ 2  (e.g., red light, green light or yellow light) after passing through the strip-shape wavelength converting element  406 . 
         [0046]    For example, when the light emitting diode chip  402  emits ultraviolet light, the wavelength converting element can emit phosphor, which is selected from the group consisting of red color, green color, blue color, and combinations thereof, to convert the ultraviolet light to the different color emergent light. In one embodiment of the invention, the wavelength converting material is selected from the group consisting of phosphor, dye, pigments, quantum dots (QDs) and combinations thereof. 
         [0047]    Although the present invention has been described in considerable detail with reference to certain embodiments thereof, other embodiments are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein. 
         [0048]    It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims.