Patent Publication Number: US-2020298760-A1

Title: Vehicle rearview mirror

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is a rearview mirror for general vehicles. 
     2. Description of the Related Art 
     A blind spot monitoring system detects objects around the body of a vehicle by a detector installed on the body of the vehicle. When the detector detects an object such as another vehicle, the driver is alerted through vision, hearing or vibration, which aids the driver to compensate the visual blind spots around the vehicle to ensure driving safety. 
     In the conventional art, for example, U.S. Pat. No. 9,227,557 B2 describes a vehicle rearview mirror with an indicate function. Referring to  FIG. 2  of the aforementioned patent, it is noted that the mirror surface  20  is provided with a light-transmissive zone  21  and an indicator device  30  is disposed behind the mirror surface  20 . The indicator device  30  includes a reflection base  31  and light emitting members  32 . The light emitting members  32  face a reflecting surface  311  of the reflection base  31 , so that the light emitted by the light emitting members  32  is reflected by the reflecting surface  311  to the light-transmissive zone  21  to indicate the user. 
     However, the conventional indicator device  30  of the rearview mirror usually uses LEDS (light emitting diodes) as the light emitting members  32 , and the LEDS are linear light sources only applicable to a small-area light-transmissive zone  21  as described in the above-mentioned patent, but inapplicable to a light-transmissive zone with a large area or a customized pattern, thereby limited in usage and still improvable. 
     SUMMARY OF THE INVENTION 
     It is one of the objectives of the present invention to make an improvement aimed at the defects of the conventional rearview mirrors so as to provide an improved vehicle rearview mirror which can show a customized pattern with a larger area. 
     A vehicle rearview mirror according to an embodiment of the present invention is provided to include a reflector and a light emitting module. The reflector has a back surface provided with a light-transmissive pattern for alerting or instructing the driver. The light emitting module is disposed behind the reflector and includes a case, a light source and a light guide. The light guide is disposed in the case and has an illuminating surface and a prism surface provided opposite to the illuminating surface for total reflection. The light guide is provided on a side thereof with an incidence surface. The light source is disposed in the case and faces the incidence surface in a way that light emitted by the light source enters the light guide through the incidence surface and the aforementioned prism surface reflects the light emitted by the light source to the illuminating surface which faces the light-transmissive pattern, thereby showing the light-transmissive pattern. 
     Through the structural design of the above-described rearview mirror, the light emitted by the light source is affected by the light guide to be uniformly projected from the illuminating surface and evenly distributed over the entire illuminating surface, so that the light emitting module is capable of emitting a large-area light. In other words, the whole light emitting module can be regarded as a surface light source, thereby applicable to various light-transmissive patterns with large area and customized design. 
     In one of the aspects, the rearview mirror may be a rear-view mirror inside the vehicle or a side-view mirror outside the vehicle. 
     In another aspect, the prism surface is a sawtooth surface. 
     In another aspect, the light source includes an LED array and the light source is fixed in the case. 
     In another aspect, the illuminating surface is a flat plane. 
     In another aspect, the light guide includes light diffusing agent therein. 
     In another aspect, for making the light emitting module stably fixed to the reflector and face the light-transmissive pattern, the light emitting module may be directly connected to the back surface of the reflector. In an alternative, the case of the light emitting module may be provided on the outer surface thereof with a bump in a way that the light emitting module can be directly connected to the back surface of the reflector by the bump. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The detailed structure, features and assembly or usage manners of the vehicle rearview mirror of the present invention will be specified in a following embodiment, but it should be understood that the following embodiment and the accompanying drawings are given for illustration only, not limitative of the claimed scope of the present invention, and wherein: 
         FIG. 1  is a perspective view of a vehicle rearview mirror of the embodiment; 
         FIG. 2  is approximately a side view of  FIG. 1 , but doesn&#39;t show a mirror mount of the rearview mirror; 
         FIG. 3  is an exploded perspective view of a light emitting module of the embodiment; 
         FIG. 4  is a sectional view of the light emitting module of the embodiment; 
         FIG. 5  is a perspective view of a light guide of the light emitting module of the embodiment; and 
         FIG. 6  is a block diagram showing the operation of a blind spot monitoring system of the embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The technology and features of the present invention will be specified in a following embodiment and the appendix drawings. The directional terms mentioned in the contents of the specification, such as ‘above’, ‘below’, ‘inside’, ‘outside’, ‘top’ and ‘bottom’, are just for illustrative description on the basis of normal usage direction, not intended to limit the claimed scope. 
     For specifying the technical features of the present invention, a following embodiment and the appendix drawings are given here under. This embodiment takes a side-view mirror outside the vehicle as an illustrative example of the rearview mirror of the present invention. 
     As shown in  FIGS. 1-2 , a rearview mirror  10  includes a reflector  20 , a light emitting module  30  and a mirror mount  40 , wherein the reflector  20  is a mirror mounted to the mirror mount  40  and the light emitting module  30  is disposed inside the mirror mount  40 . 
     The reflector  20  is adapted to show objects located around the vehicle and provided on a back surface  21  thereof with a cladding layer of aluminum or chromium for reflecting function. The cladding layer is usually very thin, thereby it is not illustrated in  FIG. 2 . Besides, the cladding layer is engraved with a light-transmissive pattern  22  by laser engraving, which is provided at a proper position on the back of the reflector  20 , such as the position relatively far away from a connecting member  41  of the mirror mount  40  as shown in this embodiment, so that light can be transmitted through the light-transmissive pattern  22  from the back surface  21  of the reflector  20  to the front surface  23  of the reflector  20 . 
     Referring to  FIGS. 2-5 , the light emitting module  30  includes a case  31 , a light source  32  and a light guide  33 . The case  31  is hollow-shaped and has an accommodating room  311 , an opening  312  and an installation surface  314 . The accommodating room  311  communicates with the outside of the light emitting module through the opening  312 . The case  31  is made of plastic and provided on the inner wall thereof with a smooth metal layer by coating for reflecting function. Besides, the case  31  is provided on the outer surface thereof with two bumps  315  in a way that the light emitting module  30  can be disposed behind the reflector  20  by the bumps  315 . Only one of the bumps  315  is shown in  FIGS. 2 and 3 . As shown in  FIGS. 3-5 , the light guide  33  is made of acrylic and includes light diffusing agent therein for increasing the light diffusivity of the light guide  33 . The light guide  33  is fixed to the case  31  by ultrasonic welding (or gluing) and covers the opening  312 . The light guide  33  has a prism surface  331  and an illuminating surface  332  which are provided opposite to each other. Besides, the light guide  30  is provided on a side thereof with an incidence surface  333 . The illuminating surface  332  is a flat plane. The prism surface  331  is a sawtooth surface including a plurality of triangle sections  334  as shown in  FIG. 5 . The triangle sections  334  extend transversely and are arranged equidistantly. The incidence surface  333  is a flat plane facing the installation surface  314 . The light source  32  in this embodiment uses LED, which includes an LED array  321  fixed on a substrate  322  by integrated circuit packaging. The light source  32  is fixed on the installation surface  314  in the accommodating room  311 . The LED array  321  can be controlled to emit light in a way that the light emitted by the light source  32  enters the light guide  33  through the incidence surface  333  and reflected or totally reflected to the illuminating surface  332  by the prism surface  331 , so that a large-area light is uniformly projected from the illuminating surface  332  to illuminate and show the light-transmissive pattern  22 , thereby enabling the driver to see the illuminated pattern  22  from the outside of the rearview mirror  10 . 
     Referring to  FIG. 6 , through the structural design of the above-described rearview mirror  10 , when a detector  71  of a blind spot monitoring system  7  of the vehicle detects another vehicle  8  (or a pedestrian) around the vehicle, the blind spot monitoring system  7  activates the light source  32  to emit light, so that the light emitted by the light source  32  is affected by the light guide  33  to be projected uniformly as a large-area light to the light-transmissive pattern  22 , thereby showing the light-transmissive pattern  22  to alert the driver for ensuring the driving safety. Through the effect of the light guide  33  broadening the area of the light, the entire light emitting module  30  can be regarded as a surface light source, thereby applicable to various light-transmissive patterns  22  with large area and customized design. 
     The above description is only an instanced embodiment of the present invention, and all equivalent changes and modifications made in accordance with the following claims should be included within the scope of the present invention.