Abstract:
A display device and wearable glasses that includes a fixing unit for maintaining the relative position between the display device and a user wearing same; an image source for generating corresponding image light according to image data; a first optical component for receiving the image light and transmitting the polarized light having a first polarization direction in the image light; and a second optical component for receiving and changing the polarized light having the first polarization direction into the polarized light having a second polarization direction perpendicular to the first polarization direction, and transmitting the polarized light having the second polarization direction to the first optical component, such that the polarized light having the second polarization direction is reflected to the eyes of the user by the first optical component.

Description:
This application claims priority to International Application No. PCT/CN2013/089564 filed Dec. 16, 2013 and to Chinese Patent Appln. 201210548711.3 filed Dec. 17, 2012; the entire contents of each are incorporated herein by reference. 
     BACKGROUND 
     This disclosure relates to optical display technique, and more particularly to a display device and a wearable glasses apparatus. 
     Wearable displays are generally divided into two kinds of wearable displays of immerging type and see-through type. Wearable displays of see-through type have got more and more attention from people since they allow a user to see a picture displayed by a display and surrounding environment of the user at the same time. 
     The wearable displays of see-through type can be applied in augmented reality (AR for short hereinafter), and the AR is a technique for applying virtual information to real world and overlapping the virtual information and real environment together in real time and interacting, which is also referred as mix reality. Information that can&#39;t be known directly in the real world can be provided to us through the AR, so as to expand our sensing ability. For example, Google glasses is a wearable glasses display device of see-through type, which allows the user to see a real surrounding environment of the user through spectacle lenses of the glasses and allows the user to see virtual image through the spectacle lenses of the glasses at the same time. 
     The current wearable displays of see-through type usually adopt a multiple layers light splitting structure to implement lightening of a wave guide system, and this structure may enlarge an exit pupil distance and an exit pupil diameter of the overall system so that a watching range of human eyes is relatively comfortable at the same time. However, a manufacturing process of such multiple layers light splitting structure is relative complex, and an ability of mass production is poor, and stray light is easy to influence a quality of a whole picture. 
     There is another kind of wearable display of see-through type, which uses a layer of semi-reflective and semi-transmitted membrane to implement the light guide system, and it is obvious that it lowers an optical utilization ratio. 
     Therefore, there needs a new display device which is easy to be manufactured and has higher optical utilization ratio. 
     SUMMARY 
     This disclosure is suggested in consideration of above problems. A purpose of this disclosure is to provide a display device which constitutes the light guide system by using a polarization light splitter and resin material to improve efficiency of light utilization significantly and easy to implement lightening. 
     According to one aspect of this disclosure, there provides a display device including: a holding unit for holding a relative position relationship between the display device and a user when the user wears the display device; an image source for generating image light corresponding to image data according to the image data; a first optical component for receiving the image light and making polarized light having a first polarization direction in the image light to pass through; and a second optical component for receiving the polarized light having the first polarization direction and converting it to a polarized light having a second polarization direction which is perpendicular to the first polarization direction, and propagating the polarized light having the second polarization direction to the first optical component, to make the polarized light having the second polarization direction to be reflected to eyes of the user by the first optical component. 
     In the display device, the first optical component is a polarization light splitter; and the second optical component includes a quarter-wave plate and a reflector, wherein, the quarter-wave plate receives the polarized light having the first polarization direction passing through the first optical component, and the reflector receives light passing through the quarter-wave plate and reflects it back to the quarter-wave plate, and then the quarter-wave plate propagates the polarized light having the second polarization direction to the first optical component. 
     The display device further includes: a third optical component which is between the image source and the first optical component and is used for propagating the image light generated by the image source to the first optical component; and a fourth optical component which is between the first optical component and the second optical component and is used for propagating the polarized light having the first polarization direction passing through the first optical component to the second optical component and for propagating the polarized light having the second polarization direction from the second optical component to the first optical component. 
     In the display device, the first optical component, the third optical component and the fourth optical component satisfy predetermined light transmittance, so that the user can not only see an image corresponding to the image data by the display device and also see the surrounding environment of the user through the display device. 
     In the display device, the third optical component and the fourth optical component are made of resin material, and a refractivity and a transmittance of the resin material is similar to those of glasses. 
     According to another aspect of this disclosure, there provides a wearable glasses apparatus including: a holding unit for holding a relative position relationship between the wearable glasses apparatus and a user when the user wears the wearable glasses apparatus; a left display unit; and a right display unit. 
     The left display unit includes: a left image source for generating left image light for being watched by a left eye of the user and corresponding to left image data according to the left image data; a first left optical component for receiving the left image light and making polarized light having a first polarization direction in the left image light to pass through; and a second left optical component for receiving the polarized light having the first polarization direction and converting it to a polarized light having a second polarization direction which is perpendicular to the first polarization direction, and propagating the polarized light having the second polarization direction to the first left optical component, to make the polarized light having the second polarization direction to be reflected to the left eye of the user by the first left optical component. 
     The right display unit includes: a right image source for generating right image light for being watched by a right eye of the user and corresponding to right image data according to the right image data; a first right optical component for receiving the right image light and making polarized light having a third polarization direction in the right image light to pass through; and a second right optical component for receiving the polarized light having the third polarization direction and converting it to a polarized light having a fourth polarization direction which is perpendicular to the third polarization direction, and propagating the polarized light having the fourth polarization direction to the first right optical component, to make the polarized light having the fourth polarization direction to be reflected to the right eye of the user by the first right optical component. 
     The left image data is same as or different from the right image data, and the first polarization direction is same as or different from the third polarization direction, and the second polarization direction is same as or different from the fourth polarization direction. 
     In the wearable glasses apparatus, the first left optical component is a left polarization light splitter and the first right optical component is a right polarization light splitter; and the second left optical component includes a left quarter-wave plate and a left reflector, and the second right optical component includes a right quarter-wave plate and a right reflector. 
     In the wearable glasses apparatus, the left display device further includes: a third left optical component which is between the left image source and the first left optical component and for propagating the left image light generated by the left image source to the first left optical component; and a fourth left optical component which is between the first left optical component and the second left optical component and for propagating the polarized light having the first polarization direction passing through the first left optical component to the second left optical component and for propagating the polarized light having the second polarization direction from the second left optical component to the first left optical component. 
     In the wearable glasses apparatus, the right display device further includes: a third right optical component which is between the right image source and the first right optical component and for propagating the right image light generated by the right image source to the first right optical component; and a fourth right optical component which is between the first right optical component and the second right optical component and for propagating the polarized light having the first polarization direction passing through the first right optical component to the second right optical component and for propagating the polarized light having the second polarization direction from the second right optical component to the first right optical component. 
     In the wearable glasses apparatus, the holding unit holds the left display unit and the right display unit in front of the left eye and the right eye of the user respectively, and holds the left display unit at a first position having a first predetermined distance from the left eye of the user and holds the right display unit at a second position having a second predetermined distance from the right eye of the user, and wherein the first predetermined distance is approximately equal to the second predetermined distance. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various kinds of features and advantages of the embodiments are more obvious and more understanding by describing the embodiments with reference to accompanying drawings, in the figures: 
         FIG. 1  schematically illustrates a schematic diagram of a structure of a display device according to a first embodiment of the disclosure; 
         FIG. 2  schematically illustrates a schematic diagram of a structure of a display device according to a second embodiment of the disclosure; 
         FIG. 3  schematically illustrates a schematic diagram of a structure of a wearable glasses apparatus according to a first embodiment of the disclosure; 
         FIG. 4  schematically illustrates a schematic diagram of a structure of a wearable glasses apparatus according to a second embodiment of the disclosure; and 
         FIG. 5  schematically illustrates appearance structures of the wearable glasses apparatus according to the first and second embodiments of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, the display device and the wearable glasses apparatus according to embodiments of this disclosure are described with reference to the accompanying drawings. 
     As shown in  FIG. 1 , it schematically illustrates a schematic diagram of structure of a display device  100  according to the first embodiment of the disclosure. 
     The display device  100  according to the first embodiment of the disclosure includes an image source  150 , a first optical component  110  and a second optical component  120 . 
     The image source  150  generates image light corresponding to image data according to the image data. 
     The first optical component  110  receives the image light and makes polarized light having a first polarization direction in the image light to pass through. 
     The second optical component  120  receives the polarized light having the first polarization direction and converts it to a polarized light having a second polarization direction which is perpendicular to the first polarization direction, and propagates the polarized light having the second polarization direction to the first optical component  110 , to make the polarized light having the second polarization direction to be reflected to eyes of a watcher (a user) by the first optical component  110 . 
     As described before, the image light is propagated to the first optical component  110  after being generated by the image source  150 , and the polarized light having the first polarization direction in the image light passes through the first optical component  110  to be propagated to the second optical component  120 , and the second optical component  120  converts the polarized light having the first polarization direction to the polarized light having the second polarization direction and propagates the polarized light having the second polarization direction to the first optical component  110 , and then the first optical component  110  reflects the polarized light having the second polarization direction to the eyes of the user. 
     Since only the polarized light having the first polarization direction in the image light can pass through the first optical component  110 , in order to improve the efficiency for light utilization, preferably, the image source  150  generates image light having the first polarization direction, in other words, the image light is preferably the polarized light having the first polarization direction. 
     The first optical component  110  may be the polarization light splitter, and the polarized light having the first polarization direction can pass through the polarization light splitter, and the polarized light having the second polarization direction which is perpendicular to the first polarization direction is reflected by the polarization light splitter. 
     The second optical component  120  may include a quarter-wave plate  122  and a reflector  121 . As shown in  FIG. 1 , the quarter-wave plate  122  receives the polarized light having the first polarization direction passing through the first optical component  110 , and the reflector  121  receives light passing through the quarter-wave plate  122  and reflects it back to the quarter-wave plate  122 , and then the quarter-wave plate  122  propagates the polarized light having the second polarization direction to the first optical component  110 . 
     In the first embodiment, preferably, a third optical component  130  is arranged between the image source  150  and the first optical component  110 . The third optical component is between the image source  150  and the first optical component  110  and is used for propagating the image light generated by the image source  150  to the first optical component  110 . 
     In the first embodiment, preferably, a fourth optical component  140  is arranged between the first optical component  110  and the second optical component  120 . The fourth optical component  140  is between the first optical component  110  and the second optical component  120  and is used for propagating the polarized light having the first polarization direction passing through the first optical component  110  to the second optical component  120  and is used for propagating the polarized light having the second polarization direction from the second optical component  120  to the first optical component  110 . 
     As shown in  FIG. 1 , the third optical component  130  may include a first optical part and a second optical part. Cross sections of the first optical part and the second optical part are shown in  FIG. 1 , wherein the cross section of the first optical part is a rectangle, the cross section of the second optical part is a triangle, and a boundary between the first optical part and the second optical part is shown by a dotted line. The first optical part and the second optical part can be provided separately, or can be provided as a whole. 
     Preferably, the first optical part is a columnar body, and the image source  150  is jointed with a first end surface of the first optical part, so that the image light generated by the image source  150  is vertically incident on the first end surface of the first optical part. 
     Preferably, the second optical part is a triangular prism, and a first edge of the second optical part is overlapping with a second end surface of the first optical part. 
     The polarization light splitter is adhered to a second edge of the triangular prism of the second optical part. 
     A cross section of the fourth optical part  140  is also shown in  FIG. 1 , and the cross section of the fourth optical part  140  is triangular. 
     Preferably, the fourth optical component  140  is a triangular prism, and the quarter-wave plate  122  is adhered to a first edge of the fourth optical component  140 , and the polarization light splitter is adhered to a second edge of the fourth optical component  140 , and light transmitted from a third edge of the fourth optical component  140  is incident to the eyes of the user. 
     Preferably, the first optical component  110  is sandwiched between the third optical component  130  and the fourth optical component  140 . 
     Further, though not shown in  FIG. 1 , the display device  100  according to the first embodiment of the disclosure may also includes a holding unit for holding a relative position relationship between the display device and the user when the user wears the display device. In particular, the holding unit is used for holding the second optical component  120  of the display device or the combination of the second optical component  120  and the fourth optical component  140  at a position of a predetermined distance from the eyes of the user. 
     The display device  100  according to the first embodiment of the disclosure as shown in  FIG. 1  may be made for being watched by one eye, or may be made for being watched by two eyes of the user at the same time. 
     Further, preferably, the first optical component  110 , the third optical component  130  and the fourth optical component  140  satisfy predetermined light transmittance, so that the user can not only see an image corresponding to the image data by the display device  100  and also see the surrounding environment of the user through the display device  100 . 
     Preferably, as shown in  FIG. 1 , in the display device  100  according to the first embodiment of the disclosure, the first edge of the triangular prism of the first optical part is perpendicular to the third edge thereof, and an angle between the first edge and the second edge is 45 degrees, and the first edge of the triangular prism of the fourth optical component is perpendicular to the third edge thereof, and an angle between the first edge and the second edge is 45 degrees. However, the present disclosure is not limited thereto. 
     The third optical component  130  and the fourth optical component  140  are preferably made of resin material, and a refractivity and a transmittance of the resin material is similar to those of glasses. Since weight of the resin material is relatively light, the display device  100  according to the first embodiment of the disclosure is easy to implement lightening. 
     On the other hand, in the display device  100  according to the first embodiment of the disclosure, an interface from an optically denser medium to an optically thinner medium is formed between the third optical component  130  and its surrounding medium, and the polarized light implements a propagation of total reflection in the third optical component  130 , a light guide is constituted by using the third optical component  130 , the polarization light splitter  110 , the fourth optical component  140  and the second optical component  120  together, so that the efficiency for light utilization is very high. 
     In another aspect, a structure of the display device  100  according to the first embodiment of the disclosure is simple, and the resin material is easy to be processed, so that a mass production is easy to be implemented. 
     As shown in  FIG. 2 , it schematically illustrates a schematic diagram of structure of a display device  200  according to the second embodiment of the disclosure. 
     The display device  200  according to the second embodiment of the disclosure includes an image source  250 , a first reflector  260 , a first optical component  210  and a second optical component  220 . 
     The image source  250  is used for generating image light corresponding to image data according to the image data. 
     The first reflector  260  receives the image light from the image source  250  and reflects the image light. 
     The first optical component  210  receives the image light and makes polarized light having a first polarization direction in the image light to pass through. 
     The second optical component  220  receives the polarized light having the first polarization direction and converts it to a polarized light having a second polarization direction which is perpendicular to the first polarization direction, and propagates the polarized light having the second polarization direction to the first optical component  210 , to make the polarized light having the second polarization direction to be reflected to eyes of a watcher (a user) by the first optical component  210 . 
     As described before, the image light is propagated to the first reflector  260  after being generated by the image source  250 , and the reflector  260  reflects the image light, so that the image light may be incident to the first optical component  210 , the polarized light having the first polarization direction in the image light passes through the first optical component  210  to be propagated to the second optical component  220 , and the second optical component  220  converts the polarized light having the first polarization direction to the polarized light having the second polarization direction and propagates the polarized light having the second polarization direction to the first optical component  210 , and then the first optical component  210  reflects the polarized light having the second polarization direction to the eyes of the user. 
     In the second embodiment, preferably, a fourth optical component  240  is arranged between the first optical component  210  and the second optical component  220 . 
     The image source  250 , the first optical component  210 , the second optical component  220  and the fourth optical component  240  are same as the image source  150 , the first optical component  110 , the second optical component  120  and the fourth optical component  240  in the display device  100  according to the first embodiment of the disclosure, and it is no longer described here for redundancy. 
     The second optical component  220  may include a quarter-wave plate  222  and a second reflector  221 , as shown in  FIG. 2 . The quarter-wave plate  222  and the second reflector  221  are same as the quarter-wave plate  122  and the second reflector  121  in the display device  100  according to the first embodiment of the disclosure, and it is no longer described here for redundancy. 
     In the second embodiment, preferably, a third optical component  230  for propagating the image light generated by the image source  250  to the first optical component  210  is further arranged between the image source  250 , the first reflector  260  and the first optical component  210 . 
     As shown in  FIG. 2 , the third optical component  230  may include a first optical part, a second optical part and a third optical part, and cross sections of the first optical part, the second optical part and the third optical part are shown, wherein the cross section of the first optical part is rectangle, the cross sections of the second optical part and the third optical part are triangle. A boundary between the first optical part and the third optical part and a boundary between the first optical part and the second optical part are shown in dotted line in  FIG. 2  respectively. The first optical part, the second optical part and the third optical part can be provided separately, or can be provided as a whole. 
     The third optical part may be a triangular prism. The image source  250  is jointed with a first edge of the third optical part, so that the image light generated by the image source  250  is incident to a second edge of the third optical part from the first edge of the third optical part. 
     The first reflector  260  is adhered to the second edge of the third optical part, and reflects the image light incident to the second edge of the third optical part to a third edge of the third optical part. 
     The first optical part is a columnar body, and the third edge of the third optical part is overlapped with a first end surface of the first optical part, so that the image light reflected by the first reflector is vertically incident on the first end surface of the first optical part. 
     Further, the first optical part and the second optical part in the display device  200  according to the second embodiment of the disclosure are same as the first optical part and the second optical part in the display device  100  according to the first embodiment of the disclosure respectively, and it is no longer described for redundancy. 
     Though the first reflector  250  and the third optical component  230  are described separately above, in case that they exist at the same time, the first reflector  260  can be as a part of the third optical component  222 , that is, the second embodiment also includes the following case: the third optical component  222  includes the first optical part, the second optical component, the third optical component and the first reflector  260 . 
     Preferably, as shown in  FIG. 2 , and in the display device  200  according to the second embodiment of the disclosure, the first edge of the triangular prism of the first optical part is perpendicular to the third edge thereof, and an angle between the first edge and the second edge is 45 degrees, and the first edge of the triangular prism of the third optical part is perpendicular to the third edge thereof, and an angle between the first edge and the second edge is 45 degrees, and a first edge of the triangular prism of the fourth optical component is perpendicular to the third edge thereof, and an angle between the first edge and the second edge is 45 degrees. 
     Preferably, the first optical component  210 , the third optical component  230  and the fourth optical component  240  satisfy predetermined light transmittance, so that the user can not only see an image corresponding to the image data by the display device  200  and also see the surrounding environment of the user through the display device  200 . 
     Further, though not shown in  FIG. 2 , the display device  200  according to the second embodiment of the disclosure may also includes a holding unit for holding a relative position relationship between the display device  200  and the user when the user wears the display device  200 . In particular, the holding unit is used for holding the second optical component  220  of the display device  200  or the combination of the second optical component  220  and the fourth optical component  240  at a position of a predetermined distance from the eyes of the user. 
     The display device  200  according to the second embodiment of the disclosure may be made for being watched by one eye, or may be made for being watched by two eyes of the user at the same time as the display device  100  according to the first embodiment of the disclosure. 
     In the display device  200  according to the second embodiment of the disclosure, the third optical component  230  and the fourth optical component  240  are preferably made of resin material, and a refractivity and a transmittance of the resin material is similar to those of glasses. Since weight of the resin material is relatively light, the display device  200  according to the second embodiment of the disclosure is easy to implement lightening. 
     On the other hand, in the display device  200  according to the second embodiment of the disclosure, an interface from an optically denser medium to an optically thinner medium is formed between the third optical component  230  and its surrounding medium, and the polarized light implements a propagation of total reflection in reflector  230 , a light guide is constituted by using the third optical component  230 , the reflector  260 , the polarization light splitter  110 , the fourth optical component  240  and the second optical component  220  together, so that the efficiency for light utilization is very high. 
     In another aspect, a structure of the display device  200  according to the second embodiment of the disclosure is simple, and the resin material is easy to be processed, so that a mass production is easy to be implemented. 
     As shown in  FIG. 3 , it schematically illustrates a schematic diagram of structure of a wearable glasses apparatus  300  according to the first embodiment of the disclosure. 
     The wearable glasses apparatus  300  of the first embodiment of the disclosure includes a holding unit (not shown in  FIG. 3 ), a left display unit  300   a  and a right display unit  300   b.    
     The left display device  300   a  and the right display unit  300   b  can adopt the display device  100  as shown in  FIG. 1 . The holding unit is for holding a relative position relationship between the wearable glasses apparatus and a user when the user wears the wearable glasses apparatus.  FIG. 5  shows an example of the holding unit. In  FIG. 5 , the left display unit  300   a  is accommodated in a first left part  511  and a second left part  521 , and the right display unit  300   b  is accommodated in a first right part  512  and a second right part  522 . 
     As shown in  FIG. 5 , the holding unit holds the left display unit  300   a  and the right display unit  300   b  in front of a left eye and a right eye of the user respectively, and in particular holds the left display unit  300   a  at a first position of a first predetermined distance from the left eye of the user, and holds the right display unit  300   b  at a second position of a second predetermined distance from the right eye of the user. The first predetermined distance is approximately equal to the second predetermined distance. 
     The left display unit  300   a  includes: a left image source  350   a , a first left optical component  310   a  and a second left optical component  320   a.    
     The left image source  350   a  generates left image light which is corresponding to left image data and being watched by the left eye of the user according to the left image data. 
     The first left optical component  310   a  receives the left image light and makes polarized light having a first polarization direction in the left image light to pass through. 
     The second left optical component  320   a  receives the polarized light having the first polarization direction and converts it to a polarized light having a second polarization direction which is perpendicular to the first polarization direction, and propagates the polarized light having the second polarization direction to the first left optical component  310   a , to make the polarized light having the second polarization direction to be reflected to the left eye of the user by the first left optical component  310   a.    
     The right display unit  300   b  includes: a right image source  350   b , a first right optical component  310   b  and a second right optical component  320   b.    
     The right image source  350   b  generates right image light which is corresponding to right image data and being watched by the right eye of the user according to the right image data. 
     The first right optical component  310   b  receives the right image light and makes polarized light having a third polarization direction in the right image light to pass through. 
     The second right optical component  320   b  receives the polarized light having the third polarization direction and converts it to a polarized light having a fourth polarization direction which is perpendicular to the third polarization direction, and propagates the polarized light having the fourth polarization direction to the first right optical component  310   b , to make the polarized light having the fourth polarization direction to be reflected to the right eye of the user by the first right optical component  310   b.    
     The left image data may be same as or different from the right image data. 
     The first polarization direction may be same as or different from the third polarization direction, correspondingly, the second polarization direction may be the same as or different from the fourth polarization direction. 
     The first left optical component  310   a  may be a left polarization light splitter and the first right optical component  310   b  may be a right polarization light splitter. 
     The second left optical component  320   a  includes a left quarter-wave plate  322   a  and a left reflector  321   a , and the second right optical component  320   b  includes a right quarter-wave plate  322   b  and a right reflector  321   b.    
     The left quarter-wave plate  322   a  receives the polarized light having the first polarization direction passing through the first left optical component  310   a , and the left reflector  321   a  receives light passing through the left quarter-wave plate  322   a  and reflects it back to the left quarter-wave plate  322   a , and then, the left quarter-wave plate  322   a  propagates the polarized light having the second polarization direction to the first left optical component  310   a.    
     Similarly, the right quarter-wave plate  322   b  receives the polarized light having the third polarization direction passing through the first right optical component  310   b , and the right reflector  321   b  receives light passing through the right quarter-wave plate  322   b  and reflects it back to the right quarter-wave plate  322   b , and then the right quarter-wave plate  322   b  propagates the polarized light having the fourth polarization direction to the first right optical component  310   b.    
     As shown in  FIG. 3 , the left display unit  300   a  may also include: a third left optical component  330   a  and a fourth left optical component  340   a.    
     The third left optical component  330   a  is between the left image source  350   a  and the first left optical component  310   a  and is used for propagating the left image light generated by the left image source  350   a  to the first left optical component  310   a.    
     The fourth left optical component  340   a  is between the first left optical component  310   a  and the second left optical component  320   a  and is used for propagating the polarized light having the first polarization direction passing through the first left optical component  310   a  to the second left optical component  320   a  and is used for propagating the polarized light having the second polarization direction from the second left optical component  320   a  to the first left optical component  310   a.    
     The right display unit  300   b  may also include: a third right optical component  330   b  and a fourth right optical component  340   b.    
     The third right optical component  330   b  is between the right image source  350   b  and the first right optical component  310   b  and is used for propagating the right image light generated by the right image source  350   b  to the first right optical component  310   b.    
     The fourth right optical component  340   b  is between the first right optical component  310   b  and the second right optical component  320   b  and is used for propagating the polarized light having the first polarization direction passing through the first right optical component  310   b  to the second right optical component  320   b  and is used for propagating the polarized light having the second polarization direction from the second right optical component  320   b  to the first right optical component  310   b.    
     Further, the first left optical component  310   a , the second left optical component  320   a , the third left optical component  330   a  and the fourth left optical component  340   a  are same as the first optical component  110 , the second optical component  120 , the third optical component  130  and the fourth optical component  140  shown in  FIG. 1  respectively, and it is no longer described here for redundancy. 
     Further, the first right optical component  310   b , the second right optical component  320   b , the third right optical component  330   b  and the fourth right optical component  340   b  are same as the first optical component  110 , the second optical component  120 , the third optical component  130  and the fourth optical component  140  shown in  FIG. 1  respectively, and it is no longer described here for redundancy. 
       FIG. 4  schematically illustrates a schematic diagram of structure of a wearable glasses apparatus according to the second embodiment of the disclosure. 
     As shown in  FIG. 4 , the wearable glasses apparatus  400  of the second embodiment of the disclosure also includes a holding unit (not shown in  FIG. 4 ), a left display unit  400   a  and a right display unit  400   b.    
     The left display device  400   a  and the right display unit  400   b  can adopt the display device as shown in  FIG. 2 . The holding unit is for holding a relative position relationship between the wearable glasses apparatus and a user when the user wears the wearable glasses apparatus.  FIG. 5  shows an example of the holding unit. In  FIG. 5 , the left display unit  400   a  is accommodated in a first left part  511  and a second left part  521 , and the right display unit  400   b  is accommodated in a first right part  512  and a second right part  522 . 
     The left display unit  400   a  includes a left image source  450   a , a first left reflector  460   a , a first left optical component  410   a  and a second left optical component  410   b.    
     The left image source  450   a  generates left image light which is corresponding to left image data and being watched by the left eye of the user according to the left image data. 
     The first left reflector  460   a  receives the left image light from the left image source  450   a  and reflects the left image light. 
     The first left optical component  410   a  receives the left image light and makes polarized light having a first polarization direction in the left image light to pass through. 
     The second left optical component  420   a  receives the polarized light having the first polarization direction and converts it to a polarized light having a second polarization direction which is perpendicular to the first polarization direction, and propagates the polarized light having the second polarization direction to the first left optical component  410   a , to make the polarized light having the second polarization direction to be reflected to the left eye of the user by the first left optical component  410   a.    
     The right display unit  400   b  includes: a right image source  450   b , a first right reflector  460   b , a first right optical component  410   b  and a second right optical component  420   b.    
     The right image source  450   b  generates right image light which is corresponding to right image data and being watched by the right eye of the user according to the right image data. 
     The first right reflector  460   b  receives the right image light from the right image source  450   b  and reflects the right image light. 
     The first right optical component  410   b  receives the right image light and makes polarized light having a third polarization direction in the right image light to pass through. 
     The second right optical component  420   b  receives the polarized light having the third polarization direction and converts it to a polarized light having a fourth polarization direction which is perpendicular to the third polarization direction, and propagates the polarized light having the fourth polarization direction to the first right optical component  410   b , to make the polarized light having the fourth polarization direction to be reflected to the right eye of the user by the first right optical component  410   b.    
     The left image data may be same as or different from the right image data. 
     The first polarization direction may be same as or different from the third polarization direction, correspondingly, the second polarization direction may be the same as or different from the fourth polarization direction. 
     The first left optical component  410   a  may be a left polarization light splitter and the first right optical component  410   b  may be a right polarization light splitter. 
     The second left optical component  420   a  includes a left quarter-wave plate  422   a  and a left reflector  421   a , and the second right optical component  420   b  includes a right quarter-wave plate  422   b  and a right reflector  421   b.    
     The left quarter-wave plate  422   a , the left reflector  421   a , the right quarter-wave plate  422   b  and the right reflector  421   b  are same as the left quarter-wave plate  322   a , the left reflector  321   a , the right quarter-wave plate  322   b  and the right reflector  321   b  shown in  FIG. 3  respectively, and it is no longer described here for redundancy. 
     As shown in  FIG. 4 , the left display unit  400   a  may also include: a third left optical component  430   a  and a fourth left optical component  440   a.    
     The right display unit  400   b  may also include: a third right optical component  430   b  and a fourth right optical component  440   b.    
     Further, the first left optical component  410   a , the second left optical component  420   a , the third left optical component  430   a  and the fourth left optical component  440   a  are same as the first optical component  210 , the second optical component  220 , the third optical component  230  and the fourth optical component  240  shown in  FIG. 2  respectively, and it is no longer described here for redundancy. 
     Further, the first right optical component  410   b , the second right optical component  420   b , the third right optical component  430   b  and the fourth right optical component  440   b  are same as the first optical component  210 , the second optical component  220 , the third optical component  230  and the fourth optical component  240  shown in  FIG. 2  respectively, and it is no longer described here for redundancy. 
       FIG. 5  schematically illustrates appearance schematic diagrams of the wearable glasses apparatus according to the first and second embodiments of the disclosure. 
     As shown in  FIG. 5 , the holding device includes a first holding portion  540 , a second holding portion  510  and a third holding portion  530 . 
     The first holding portion  540  is positioned at left side of the left display unit ( 300   a  or  400   a ) accommodated in  512  and  522 , and includes a straight line portion and a bent portion for bracketing on a left ear of the user. 
     The second holding portion  530  is positioned at right side of the right display unit ( 300   b  or  400   b ) accommodated in  511  and  521 , and includes a straight portion and a bent portion for bracketing on a right ear of the user. 
     The third holding portion  510  is positioned between the left display unit and the right display unit for bracketing on a nose of the user. 
     However, implement forms of the wearable glasses apparatus according to the first and second embodiments of the disclosure are not limited to appearance shapes as shown in  FIG. 5 , but have different appearance shapes according to different needs, this disclosure is not limited to a specific implement form of appearance thereof. 
     The display device and the wearable glasses apparatus according to this disclosure not only have a higher optical utilization ratio and also easy to implement lightening, and is easier to implement mass production. 
     The display device and the wearable glasses apparatus according to this disclosure are described with reference to the accompanying drawings above. Those skilled in the art can understand, this disclosure is not limited to the above-described embodiments, and various modifications can be made without departing from a spirit of this disclosure, and these modifications should be included in a range of this disclosure. The range of this disclosure should be defined by append claims and equivalence thereof.