Patent Publication Number: US-2016238207-A1

Title: Vehicle lamp module and lens

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of Taiwan application serial no. 104104722, filed on Feb. 12, 2015. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification. 
     FIELD OF THE INVENTION 
     The invention relates to a light source module and an optical device; more particularly, the invention relates to a vehicle lamp module and a lens. 
     DESCRIPTION OF RELATED ART 
     The lens in most of the vehicle lamps, for example, the vehicle lamp using a light emitting diode (LED) as the light source, is characterized by one single lens. According to the optical principle, the thickness ratio of the lens determines the level of dispersion. 
     The color shift issue is normally resolved by using a doublet lens consisting of a positive lens and a negative lens which are respectively made of materials with different dispersion characteristics and are adhered to each other, and thereby the dispersion issue can be resolved. However, the use of the doublet lens may reduce the optical efficiency, increase weight and the manufacturing costs, and increase the back focal length which may have influence on the volume of the entire system. Besides, the adhesive used to adhere the two lenses to each other may have an issue on reliability. For example, the adhesive may be degraded if it is placed in a high-temperature environment for a long period of time. Moreover, it is difficult to find two compatible plastic materials for mass production by using an injection molding process. 
     China Patent Application Publication No. 103629625A discloses a light guiding unit featuring microstructures. China Utility Patent No. 201017045Y discloses an aspheric lens with the design of one single lens. U.S. Pat. No. 6,352,359B1 discloses a lens cap or a cap located on the casing. 
     The information disclosed in this “Description of Related Art” section is only for enhancement understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Furthermore, the information disclosed in this “Description of Related Art” section does not mean that one or more problems to be solved by one or more embodiments of the invention were acknowledged by a person of ordinary skill in the art. 
     SUMMARY OF THE INVENTION 
     The invention is directed to a vehicle lamp module capable of effectively resolving the issue of dispersion. 
     The invention is also directed to a lens capable of effectively resolving the issue of dispersion. 
     Other objectives and advantages of the invention can be further illustrated by the technical features broadly embodied and described as follows. 
     To achieve one, a part, or all of the above advantages or other advantages, an embodiment of the invention provides a vehicle lamp module and a lens having microstructures. In an embodiment of the invention, a vehicle lamp module including a light emitting device and a lens is provided. The light emitting device is capable of emitting light, and the lens has a light input surface and a light output surface opposite to each other. At least a portion of the light from the light emitting device sequentially passes through the light input surface and the light output surface. A central region of the light output surface has a plurality of cylindrical surface microstructures. A depth of the cylindrical surface microstructures in a direction parallel to an optical axis of the lens is within a range from 0.02 millimeter to 0.2 millimeter. 
     To achieve one, a part, or all of the above advantages or other advantages, an embodiment of the invention provides a lens that includes a light input surface and a light output surface. The light output surface is opposite to the light input surface. A central region of the light output surface has a plurality of cylindrical surface microstructures. A depth of the cylindrical surface microstructures in a direction parallel to an optical axis of the lens is within a range from 0.02 millimeter to 0.2 millimeter. 
     According to an embodiment of the invention, the central region substantially coincides with an orthogonal projection of the light input surface along the optical axis on the light output surface. 
     According to an embodiment of the invention, the light output surface is a convex curved surface. 
     According to an embodiment of the invention, the cylindrical surface microstructures are convex cylindrical surfaces or concave cylindrical surfaces. 
     According to an embodiment of the invention, the cylindrical surface microstructures are arranged along a first direction, each of the cylindrical surface microstructures extends along a second direction, and curvature radii of the cylindrical surface microstructures gradually decrease from a central portion of the central region to two end portions of the central region along a direction substantially parallel to the first direction. 
     According to an embodiment of the invention, the cylindrical surface microstructures are arranged along a first direction, each of the cylindrical surface microstructures extends along a second direction, and curvature radii of the cylindrical surface microstructures gradually increase from a central portion of the central region to two end portions of the central region along a direction substantially parallel to the first direction. 
     According to an embodiment of the invention, the cylindrical surface microstructures are arranged along a first direction, each of the cylindrical surface microstructures extends along a second direction, and a pitch of the cylindrical surface microstructures along the first direction is within a range from 0.1 millimeter to 3 millimeters. 
     According to an embodiment of the invention, the cylindrical surface microstructures are arranged along a first direction, each of the cylindrical surface microstructures extends along a second direction, and the cylindrical surface microstructures closely adjoin each other along the first direction. 
     According to an embodiment of the invention, the cylindrical surface microstructures are arranged along a first direction, each of the cylindrical surface microstructures extends along a second direction, and the cylindrical surface microstructures are spaced from each other along the first direction. 
     According to an embodiment of the invention, the lens further includes an inner surrounding surface and an outer connection surface. The inner surrounding surface is connected to the light input surface, and the inner surrounding surface and the light input surface constitute a recess containing the light emitting device. The outer connection surface connects the inner surrounding surface and the light output surface. 
     In the embodiments of the vehicle lamp module and the lens of the present invention, the central region of the light output surface has the cylindrical surface microstructures, and the depth of the cylindrical surface microstructures in the direction parallel to the optical axis of the lens is within a range from 0.02 millimeter to 0.2 millimeter. Therefore, the embodiments can achieve favorable light diffusion effects and further effectively resolve the issue of dispersion resulting from the refraction by the lens. 
     Other features and advantages of the invention will be further understood from the further technological features disclosed by the embodiments of the invention wherein there are shown and described embodiments of this invention, simply by way of illustration of modes suited to carry out the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
         FIG. 1A  is a schematic front view illustrating a vehicle lamp module according to an embodiment of the invention. 
         FIG. 1B  is a schematic side view illustrating the vehicle lamp module depicted in  FIG. 1A . 
         FIG. 1C  is a schematic cross-sectional view illustrating the vehicle lamp module depicted in  FIG. 1A  along a line I-I. 
         FIG. 1D  is a schematic three-dimensional view illustrating the cylindrical surface microstructures depicted in  FIG. 1A . 
         FIG. 2  is a schematic cross-sectional view illustrating a portion of a lens according to another embodiment of the invention. 
         FIG. 3  is a schematic cross-sectional view illustrating a portion of a lens according to still another embodiment of the invention. 
         FIG. 4  is a schematic cross-sectional view illustrating a portion of a lens according to still another embodiment of the invention. 
         FIG. 5  is a schematic cross-sectional view illustrating a portion of a lens according to still another embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS 
     In the following detailed description of the embodiments, reference is made to the accompanying drawings which form a part hereof, and in which are shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology, such as “top,” “bottom,” “front,” “back,” etc., is used with reference to the orientation of the Figure(s) being described. The components of the invention can be positioned in a number of different orientations. As such, the directional terminology is used for purposes of illustration and is in no way limiting. 
     On the other hand, the drawings are only schematic and the sizes of components may be exaggerated for clarity. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the invention. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless limited otherwise, the terms “connected,” “coupled,” and “mounted” and variations thereof herein are used broadly and encompass direct and indirect connections, couplings, and mountings. Similarly, the terms “facing,” “faces” and variations thereof herein are used broadly and encompass direct and indirect facing, and “adjacent to” and variations thereof herein are used broadly and encompass directly and indirectly “adjacent to”. Therefore, the description of “A” component facing “B” component herein may contain the situations that “A” component directly faces “B” component or one or more additional components are between “A” component and “B” component. Also, the description of “A” component “adjacent to” “B” component herein may contain the situations that “A” component is directly “adjacent to” “B” component or one or more additional components are between “A” component and “B” component. Accordingly, the drawings and descriptions will be regarded as illustrative in nature and not as restrictive. 
       FIG. 1A  is a schematic front view illustrating a vehicle lamp module according to an embodiment of the invention.  FIG. 1B  is a schematic side view illustrating the vehicle lamp module depicted in  FIG. 1A .  FIG. 1C  is a schematic cross-sectional view illustrating the vehicle lamp module depicted in  FIG. 1A  along a line I-I.  FIG. 1D  is a schematic three-dimensional view illustrating the cylindrical surface microstructures depicted in  FIG. 1A . With reference to  FIG. 1A  to  FIG. 1D , the vehicle lamp module  100  provided in the present embodiment includes a light emitting device  110  and a lens  200 . The light emitting device  110  serves to emit light  112 . According to the present embodiment, the light emitting device  110  is, for instance, a light emitting diode (LED). However, in other embodiments, the light emitting device  110  may also be a mercury light bulb, a halogen light bulb, an incandescent light bulb, a laser diode, a solid state light source, or any other appropriate light emitting device. 
     As exemplarily indicated in  FIG. 1C , the lens  200  has a light input surface (i.e., light incident surface)  210  and a light output surface  220  opposite to each other. At least a portion of the light  112  from the light emitting device  110  sequentially passes through the light input surface  210  and the light output surface  220 . As shown in  FIG. 1A  and  FIG. 1C , a central region C of the light output surface  220  has a plurality of cylindrical surface microstructures  222 . The cylindrical surface microstructures  222 , for example, are the lenticular lenses. A depth D of the cylindrical surface microstructures  222  in a direction parallel to an optical axis A of the lens  200  is within a range from 0.02 millimeter to 0.2 millimeter. 
     According to the present embodiment, the lens  200  further includes an inner surrounding surface  230  and an outer connection surface  240 . The inner surrounding surface  230  is connected to the light input surface  210 , and the inner surrounding surface  230  and the light input surface  210  constitute a recess  205  containing the light emitting device  110 . As exemplarily indicated in  FIG. 1C , the top surface of the recess  205  is the light input surface  210 , and the lateral surface of the recess  205  is the inner surrounding surface  230 . The outer connection surface  240  connects the inner surrounding surface  230  and the light output surface  220 . In the present embodiment, a portion  112   a  of the light  112  emitted from the light emitting device  110  sequentially passes through the light input surface  210  and the cylindrical surface microstructures  222 , and the cylindrical surface microstructures  222  are capable of diffusing the portion  112   a  of the light  112 . In addition, a portion  112   b  of the light  112  emitted from the light emitting device  110  sequentially passes through the light input surface  210  and the region of the light output surfaces  220  other than the central region C, i.e., the portion  112   b  of the light  112  does not pass through the cylindrical surface microstructures  222 , and the portion  112   b  is refracted by the light input surface  210  and the light output surface  220 . A portion  112   c  of the light  112  emitted from the light emitting device  110  sequentially passes through the inner surrounding surface  230 , is reflected (e.g., totally internally reflected) by the outer connection surface  240 , and passes through the region of the light output surface  220  other than the central region C. Hence, the portion  112   c  of the light  112  is subject to the refraction by the inner surrounding surface  230  and the light output surface  220  and the reflection by the outer connection surface  240 . When the regions illuminated by the portions  112   a ,  112   b , and  112   c  of light are added up, the diffusion of the portion  112   a  of the light  112  by the cylindrical surface microstructures  222  can effectively lower the level of dispersion in the whole illuminated region. That is, color breakup caused by dispersion cannot be easily observed on the edges of the illuminated region. As exemplarily indicated in  FIG. 1C , in one embodiment, the light input surface faces the emitting side (e.g., emitting surface) of the light emitting device  110 . The light output surface  220  having the cylindrical surface microstructures  222  and the light emitting device  110  are located at the opposite sides of the light input surface  210 . When the portion  112   c  of light entering the inner surrounding surface  230 , the inner surrounding surface  230  serves as the second light input surface, while the light input surface  210  facing the emitting side of the light emitting device  110  serves as the first light input surface. 
     According to the present embodiment, in the vehicle lamp module  100  and the lens  200 , the central region C of the light output surface  220  has the cylindrical surface microstructures  222 , and the depth D of the cylindrical surface microstructures  222  in the direction parallel to the optical axis A of the lens  200  is within a range from 0.02 millimeter to 0.2 millimeter so that the embodiment can achieve favorable light diffusion effects and further effectively resolve the issue of dispersion resulting from the refraction by the lens  200 . In the present embodiment, the cylindrical surface microstructures  222  are located on the central region C rather than on the entire light output surface  220 . Therefore, the light loss of the vehicle lamp module  100  at the center of the illuminated region (i.e., the location on or near the optical axis) with the maximum brightness can be reduced. Additionally, the depth D of the cylindrical surface microstructures  222  is within the range from 0.02 millimeter to 0.2 millimeter and is not excessively large, the light loss at the center of the illuminated region with the maximum brightness can be effectively reduced as well. Moreover, the depth D of the cylindrical surface microstructures  222  is not excessively small, therefore, the difficulties of forming the cylindrical surface microstructures  222  by performing the injection molding process can be prevented to better extent. 
     According to the present embodiment, the cylindrical surface microstructures  222  are arranged along a first direction D 1 , and each of the cylindrical surface microstructures  222  extends along a second direction D 2 . For instance, the first direction D 1  is substantially parallel to the direction x, and the second direction D 2  is substantially parallel to the direction y as observed in the front view of the lens  100  from the side of the output surface as exemplarily shown in  FIG. 1A . As exemplarily indicated in  FIG. 1A , in one embodiment, the second direction D 2  is substantially parallel to the widthwise of the lens  200 , and the first direction D 1  is perpendicular to the second direction D 2 . However, in the side view as shown in  FIG. 1B , for instance, the first direction D 1  may conform to the shape (e.g., bending) of the light output surface  220 ; similarly, the second direction D 2  may conform to the shape (e.g., bending) of the light output surface  220 . In other words, in one embodiment, the cylindrical surface microstructures  222  can be arranged in an arc shape along the first direction D 1 , and each of the cylindrical surface microstructures  222  can extend in an arc shape along the second direction D 2 . According to the present embodiment, the cylindrical surface microstructures  222  closely adjoin each other along the first direction D 1 . Here, the directions x, y, and z are perpendicular to one another, and the direction z is substantially parallel to the optical axis A. 
     In the present embodiment, the light output surface  220  and the light input surface  210  can both be curved surfaces, e.g., convex curved surfaces, so as to condense light or diffuse light. In addition, according to the present embodiment, the cylindrical surface microstructures  222  may be convex cylindrical surfaces. However, in another embodiment, the cylindrical surface microstructures  222  may be concave cylindrical surfaces. In an embodiment of the invention, a pitch P of the cylindrical surface microstructures  222  along the first direction D 1  is within a range from 0.1 millimeter to 3 millimeters. In the present embodiment, the curvature radius (i.e., the curvature radius shown in the cross-sectional view of  FIG. 1C ) of each of the cylindrical surface microstructures  222  are substantially the same. However, in another embodiment of the invention, the curvature radii of the cylindrical surface microstructures  222  may be completely different; alternatively, some of the curvature radii are the same, while some of the curvature radii are different. 
     In the present embodiment, an orthogonal projection of the light input surface  220  along the optical axis A on the light output surface  220  (e.g., the orthogonal projection on the light output surface  220  within a range defined by two dotted lines on two sides of the optical axis A, as exemplarily shown in  FIG. 1C ) substantially coincides with the central region C (e.g., the region of the light output surface  220  within the range defined by the two dotted lines). 
       FIG. 2  is a schematic cross-sectional view illustrating a portion of a lens according to still another embodiment of the invention. With reference to  FIG. 2 , the lens  200   a  provided in the present embodiment is similar to the lens  200  depicted in  FIG. 1C , and the difference between these two lenses  200   a  and  200  is described below. In the lens  200   a  according to the present embodiment, the cylindrical surface microstructures  222   a  of the light output surface  220   a  are concave cylindrical surfaces. 
       FIG. 3  is a schematic cross-sectional view illustrating a portion of a lens according to still another embodiment of the invention. With reference to  FIG. 3 , the lens  200   b  provided in the present embodiment is similar to the lens  200  depicted in  FIG. 1C , and the difference between these two lenses  200   b  and  200  is described below. In the lens  200   b  according to the present embodiment, the curvature radii R (e.g., the curvature radii shown in the cross-sectional view as shown in  FIG. 3 ) of the cylindrical surface microstructures  222   b  of the light output surface  220   b  gradually decreases from a central portion of the central region C to two end portions of the central region C along a direction substantially parallel to the first direction D 1 . The change of the curvature radii R of the cylindrical surface microstructures in gradual  222   b  is facilitate the alleviation of the dispersion and the increase in the large-angle illumination brightness. 
       FIG. 4  is a schematic cross-sectional view illustrating a portion of a lens according to still another embodiment of the invention. With reference to  FIG. 4 , the lens  200   c  provided in the present embodiment is similar to the lens  200  depicted in  FIG. 1C , and the difference between these two lenses  200   c  and  200  is described below. In the lens  200   c  according to the present embodiment, the curvature radii R (e.g., the curvature radii shown in the cross-sectional view as shown in  FIG. 4 ) of the cylindrical surface microstructures  222   c  of the light output surface  220   c  gradually increases from a central portion of the central region C to two end portions of the central region C along a direction substantially parallel to the first direction D 1 . 
       FIG. 5  is a schematic cross-sectional view illustrating a portion of a lens according to still another embodiment of the invention. With reference to  FIG. 5 , the lens  200   d  provided in the present embodiment is similar to the lens  200  depicted in  FIG. 1C , and the difference between these two lenses  200   d  and  200  is described below. In the lens  200   d  provided in the present embodiment, the cylindrical surface microstructures  222   d  of the light output surface  220   d  are spaced from each other along the first direction D 1  by the same interval T, for instance. Such a design may further reduce the light loss at the center of the illuminated region, and the issue of dispersion can be resolved to a certain degree. 
     Table 1 provided below lists a vehicle lamp module having no cylindrical surface microstructure according to an embodiment, the vehicle lamp module  100  shown in  FIG. 1C , and the vehicle lamp module having the lens  200   b  depicted in  FIG. 3 , and also indicates the simulation results of brightness at different test points according to Transport Regulation No. 112 stipulated by the United Nations Economic Commission for Europe (ECE). 
     
       
         
           
               
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                   
                   
                   
                   
                 Loss ratio of brightness of 
               
               
                   
                 vehicle lamp 
                   
                 vehicle lamp 
                 the vehicle lamp module having 
               
               
                   
                 module having 
                 vehicle lamp 
                 module having 
                 the lens depicted in FIG. 3 to 
               
               
                   
                 no cylindrical 
                 module 100 
                 the lens 
                 brightness of vehicle lamp 
               
               
                   
                 surface 
                 shown 
                 depicted 
                 module having no cylindrical 
               
               
                 ECE R112 
                 microstructure 
                 in FIG. 1C 
                 in FIG. 3 
                 surface microstructure 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 Imax (maximum 
                 47,376 
                 47,491 
                 45,855 
                 −3.21% 
               
               
                 brightness) 
               
               
                 H-5L (5 degrees 
                 11,465 
                 9,988 
                 10,100 
                 −11.91% 
               
               
                 left from the 
               
               
                 center) 
               
               
                 H-2.5L(2.5 
                 31,014 
                 29,600 
                 29,677 
                 −4.31% 
               
               
                 degrees left 
               
               
                 from the center) 
               
               
                 H-2.5R(2.5 
                 29,963 
                 29,659 
                 28,770 
                 −3.98% 
               
               
                 degrees right 
               
               
                 from the center) 
               
               
                 H-5R(5 degrees 
                 10,526 
                 9,863 
                 9,543 
                 −9.34% 
               
               
                 right from the 
               
               
                 center) 
               
               
                   
               
            
           
         
       
     
     The “center” shown in Table 1 indicates the center of the illuminated region, i.e., where the optical axis A is located. “2.5 degrees right from the center” indicates a test point deviated from the optical axis A by 2.5 degrees along the direction +x, and the other test points can be deduced therefrom by analogy. It can be learned from Table 1 that the dispersion can be effectively alleviated while the brightness is not reduced significantly (especially the brightness at the center of the illuminated region is not reduced significantly) according to an embodiment of the invention. Besides, the lenses  200 ,  200   a ,  200   b ,  200   c , and  200   d  can be made of single one material, and thus the conventional issue of using the doublet lens can be prevented. Further, according to Table 1, the lenses  200 ,  200   a ,  200   b ,  200   c , and  200   d  provided in the embodiments of the invention are applicable to high beam lamps for vehicles and are compliant with relevant laws and regulations. 
     In the embodiments of the vehicle lamp module and the lens of the present invention, the central region of the light output surface has the cylindrical surface microstructures, and the depth of the cylindrical surface microstructures in the direction parallel to the optical axis of the lens is within a range from 0.02 millimeter to 0.2 millimeter. Therefore, the embodiments can achieve favorable light diffusion effects and further effectively resolve the issue of dispersion resulting from the refraction by the lens. 
     The foregoing description of the preferred embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form or to exemplary embodiments disclosed. Accordingly, the foregoing description should be regarded as illustrative rather than restrictive. Obviously, many modifications and variations will be apparent to practitioners skilled in this art. The embodiments are chosen and described in order to best explain the principles of the invention and its best mode practical application, thereby to enable persons skilled in the art to understand the invention for various embodiments and with various modifications as are suited to the particular use or implementation contemplated. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents in which all terms are meant in their broadest reasonable sense unless otherwise indicated. Therefore, the term “the invention” or the like does not necessarily limit the claim scope to a specific embodiment, and the reference to particularly preferred exemplary embodiments of the invention does not imply a limitation on the invention, and no such limitation is to be inferred. The invention is limited only by the spirit and scope of the appended claims. Moreover, these claims may refer to use “first”, “second”, etc. following with noun or element. Such terms should be understood as a nomenclature and should not be construed as giving the limitation on the number of the elements modified by such nomenclature unless specific number has been given. The abstract of the disclosure is provided to comply with the rules requiring an abstract, which will allow a searcher to quickly ascertain the subject matter of the technical disclosure of any patent issued from this disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Any advantages and benefits described may not apply to all embodiments of the invention. It should be appreciated that variations may be made in the embodiments described by persons skilled in the art without departing from the scope of the invention as defined by the following claims. Moreover, no element and component in the present disclosure is intended to be dedicated to the public regardless of whether the element or component is explicitly recited in the following claims.