Abstract:
A head-up display device includes a housing, a guiding base, a projecting board assembly, a protecting cover and a driving mechanism. The projecting board assembly is movably arranged at the guiding base. The driving mechanism includes a link, a lever, and a drive wheel. A front end of the link is pivotally connected to the protecting cover, and a rear end of the link is engaged with the drive wheel. A lower end of the lever is pivotally connected to the projecting board assembly. The drive wheel is rotatable and can be selectively engaged with the lever. The rotation of the drive wheel can drive the link and the lever to move and thus drive the protecting cover and the projecting board assembly to move. Therefore, the driving mechanism can be more easily arranged, so as to simplify the structure and reduce cost.

Description:
TECHNICAL FIELD 
       [0001]    The present invention provides a head-up display device and particularly a head-up display device having a slidable projecting board assembly. 
       BACKGROUND ART 
       [0002]    A head-up display (HUD) is a device for projecting instrument-related information onto a windshield. Compared to a traditional instrument panel, the HUD enables a driver to see required important information without lowering his/her head. Therefore, the driver can see instrument-related information and watch out for road conditions at the same time. 
         [0003]    HUDs having a slidable projecting board assembly have been successively proposed, where vehicle information is displayed by the projecting board assembly which is slid upwards and extended outward, and when the use of the projecting board assembly is stopped, the projecting board assembly is slid downwards and retracted into a housing of an instrument panel assembly. Conventional HUDs are not provided with a protecting cover or a light source protecting cover, so they tend to be exposed to sunshine or adhered with dust, thereby resulting in the damage to the projecting board or the light source element. Some conventional HUDs are provided with a protecting cover, but the arrangement of such a protecting cover necessarily leads to complicated driving mechanisms and increased costs, let alone further arrangement of a light source protecting cover. 
         [0004]    In view of the above disadvantages, after an extensive research in conjunction with theoretical knowledge, the inventors provide this invention that is reasonably designed and effectively improves upon the above disadvantages. 
       SUMMARY OF THE INVENTION 
       [0005]    The objective of the present invention is to provide an HUD device, which has a protecting cover, thereby achieving an effect of protecting a projecting board to prevent the projecting board from being exposed to sunshine or adhered with dust. In addition, the arrangement of a driving mechanism is relatively easy, so as to simplify the structure and reduce cost. 
         [0006]    In order to achieve the above objective, the present invention provides an HUD device, comprising: a housing provided with an opening; a guiding base located below the housing; a projecting board assembly disposed at the guiding base, the projecting board assembly being slidably movable between a storing position which is located below the opening of the housing and a displaying position which is located outside the housing, the projecting board assembly comprising a holder and a projecting board which is disposed on the holder; a protecting cover disposed at the housing, the protecting cover being slidably movable between a closed position which is located at the opening of the housing and an open position which is located distal from the opening of the housing; and a driving mechanism comprising a link, a lever, and a driving wheel, wherein one end of the link is pivotally connected to the protecting cover, the other end of the link is engaged with the driving wheel, one end of the lever is pivotally connected to the projecting board assembly, and the driving wheel may be selectively engaged with the lever, such that when the driving wheel rotates, the link and the lever may be driven to move, thereby driving the protecting cover and the projecting board assembly to move; wherein when the driving wheel rotates in a direction, the driving wheel drives the link to rotate such that the protecting cover is moved from the closed position to the open position, and the driving wheel drives the lever to swing such that the projecting board assembly is moved from the storing position to the displaying position. 
         [0007]    In order to achieve the above objective, the present invention further provides an HUD device, comprising: a housing provided with an opening and a light source aperture; a guiding base located below the housing; a projecting board assembly disposed at the guiding base, the projecting board assembly being slidably movable between a storing position which is located below the opening of the housing and a displaying position which is located outside the housing, the projecting board assembly comprising a holder and a projecting board which is disposed on the holder; a protecting cover disposed at the housing, the protecting cover being slidably movable between a first closed position which is located at the opening of the housing and a first open position which is located distal from the opening of the housing; a light source protecting cover disposed at the housing, the light source protecting cover being pivotally movable between a second closed position which is located at the light source aperture of the housing and a second open position which is located distal from the light source aperture of the housing; and a driving mechanism comprising a link, a lever and a driving wheel, wherein one end of the link is pivotally connected to the protecting cover, the other end of the link is engaged with the driving wheel, one end of the lever is pivotally connected to the projecting board assembly, the other end of the lever is engaged with the light source protecting cover, and the driving wheel is capable of being engaged with the lever, such that when the driving wheel rotates, the link and the lever may be driven to move, thereby driving the protecting cover, the projecting board assembly and the light source protecting cover to move; wherein when the driving wheel rotates in a direction, the driving wheel drives the link to rotate such that the protecting cover is moved from the first closed position to the first open position, and the driving wheel drives the lever to swing such that the projecting board assembly is moved from the storing position to the displaying position and the light source protecting cover is pivoted from the second closed position to the second open position. 
         [0008]    The present invention at least has the following advantages: 
         [0009]    The projecting board assembly of the present invention comprises the holder and the projecting board, wherein the protecting cover can cover the projecting board of the projecting board assembly, thereby achieving the effect of protecting the projecting board to prevent the projecting board from being exposed to sunshine or adhered with dust. In addition, the rotation of the driving wheel may drive the link and the lever to move and thus drive the protecting cover and the projecting board assembly to move. As such, only one driving wheel is required for driving all the objects, and thus the arrangement of the driving mechanism is relatively easy, so as to simplify the structure and reduce cost. 
         [0010]    Furthermore, according to the present invention, the light source protecting cover is further disposed on the housing, and the other end of the lever is engaged with the light source protecting cover, such that the rotation of the driving wheel may drive the lever to move and thus drive the light source protecting cover to move. Thus, no other driving mechanisms are required for driving the light source protecting cover, which also simplifies the structure and reduces cost. 
         [0011]    In order to further understand the features and technical content of the present invention, reference can be made to the detailed description and accompanying drawings of the present invention. However, the accompanying drawings are only provided for reference and illustration, but not intended to limit the present invention. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0012]      FIG. 1  is a perspective view ( 1 ) of an HUD device according to the present invention. 
           [0013]      FIG. 2  is a perspective view ( 2 ) of the HUD device according to the present invention. 
           [0014]      FIG. 3  is a partially exploded view ( 1 ) of the HUD device according to the present invention. 
           [0015]      FIG. 4  is a partially exploded view ( 2 ) of the HUD device according to the present invention. 
           [0016]      FIG. 5  is an exploded view ( 1 ) of the HUD device according to the present invention. 
           [0017]      FIG. 6  is an exploded view ( 2 ) of the HUD device according to the present invention. 
           [0018]      FIG. 7  is a schematic plan view ( 1 ) of the HUD device according to the present invention. 
           [0019]      FIG. 8  is a schematic plan view ( 2 ) of the HUD device according to the present invention. 
           [0020]      FIG. 9  is a schematic diagram ( 1 ) illustrating operation of the HUD device according to the present invention. 
           [0021]      FIG. 10  is a schematic diagram ( 2 ) illustrating operation of the HUD device according to the present invention. 
           [0022]      FIG. 11  is a schematic diagram ( 3 ) illustrating operation of the HUD device according to the present invention. 
           [0023]      FIG. 12  is a schematic diagram ( 4 ) illustrating operation of the HUD device according to the present invention. 
           [0024]      FIG. 13  is a schematic diagram ( 5 ) illustrating operation of the HUD device according to the present invention. 
           [0025]      FIG. 14  is a schematic diagram ( 6 ) illustrating operation of the HUD device according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0026]    Referring to  FIG. 1  and  FIG. 2 , the present invention provides an HUD device, particularly an HUD device having a slidable projecting board assembly, comprising a housing  10 , a guiding base  11 , a projecting board assembly  12 , a protecting cover  13 , and a driving mechanism  14 . 
         [0027]    Also referring to  FIG. 3  and  FIG. 4 , the housing  10  may be a part of an instrument board housing or may be otherwise combined with the instrument board housing, and may be suitably mounted on a vehicle. The housing  10  is provided with an opening  101 . 
         [0028]    The guiding base  11  is located below the housing  10 . The guiding base  11  in the present embodiment is of a two-piece design, but also may be of a one-piece design, which may suitably vary depending upon the actual design requirements. 
         [0029]    The projecting board assembly  12  is slidably disposed at the guiding base  11 . The projecting board assembly  12  may be located outside the housing  10  by being slid upward and extended outward through the opening  101  (please refer to  FIG. 11 ), and may be located below the housing  10  by being slid downward and retracted (please refer to  FIG. 7 ). In particular, the projecting board assembly  12  comprises a holder  121  and a projecting board  122 . The projecting board  122  is preferably, but not limited to an arc board. The projecting board  122  is disposed on the holder  121 , namely, one end of the projecting board  122  may be inserted and fixed to the holder  121  (see  FIG. 1 ) such that the projecting board  122  and the holder  121  are integrally connected, so as to use the holder  121  to drive the projecting board  122  to move synchronously. The holder  121  may be connected to the driving mechanism  14 , such that the projecting board assembly  12  may be slidably disposed at the guiding base  11  through the driving of the driving mechanism  14 . The detailed construction of the driving mechanism  14  will be described later. 
         [0030]    Further, referring to  FIG. 5  to  FIG. 7 , a first guiding mechanism  15  (as shown in  FIG. 7 ) is provided between the projecting board assembly  12  and the guiding base  11 , for guiding movement of the projecting board assembly  12 . The construction of the first guiding mechanism  15  is not limited, and may be a combination of a guiding groove with a guiding post, or a combination of a guiding rail with a guiding block, or other existing guiding mechanisms. 
         [0031]    In the present embodiment, the first guiding mechanism  15  comprises a first guiding groove  151  and a first guiding post  152 . The first guiding groove  151  is disposed at the inner side of the guiding base  11 . The first guiding groove  151  is generally arc-shaped. The first guiding post  152  is disposed at the outer side of the holder  121 . The first guiding post  152  is slidably disposed in the first guiding groove  151 . The number of the first guiding post  152  may correspond to the number of the first guiding groove  151 . As shown in  FIGS. 5 and 6 , the first guiding post  152  can be disposed at two sides of the holder  121  and the first guiding groove  151  can be disposed at the opposing sides of the guiding base  11 . The driving mechanism  14  can drive the projecting board assembly  12  to move under the guidance of the first guiding mechanism  15 , which will be described later. 
         [0032]    The protecting cover  13  is slidably disposed at the housing  10 . The protecting cover  13  is a cover for covering the projecting board  122 . The protecting cover  13  can cover the projecting board  122  or uncover to expose the projecting board  122 . In particular, the protecting cover  13  may be slid in a direction away from the opening  101  to expose the opening  101  and thus expose the projecting board  122  (please refer to  FIG. 9 ). The protecting cover  13  may be slid in a direction toward the opening  101  to cover the opening  101  and thus cover the projecting board  122  to protect the projecting board  122  (please refer to  FIG. 7 ). The protecting cover  13  may be connected to the driving mechanism  14 , such that the protecting cover  13  may be slidably disposed at the housing  10  through the driving of the driving mechanism  14 . 
         [0033]    Further, a second guiding mechanism  16  (as shown in  FIG. 7 ) is provided between the protecting cover  13  and the housing  10 , for guiding movement of the protecting cover  13  at the opening  101 . The construction of the second guiding mechanism  16  is not limited, and may be a combination of a guiding groove with a guiding post, or a combination of a guiding rail with a guiding block, or other existing guiding mechanisms. 
         [0034]    In the present embodiment, the second guiding mechanism  16  comprises a second guiding groove  161  and a second guiding post  162 . The second guiding groove  161  is disposed at the housing  10 . The second guiding groove  161  is disposed at the opening  101  of the housing  10 . The second guiding groove  161  is generally arc-shaped. The second guiding post  162  is disposed at the protecting cover  13 . The second guiding post  162  is disposed at the outer side of the protecting cover  13 . The second guiding post  162  is slidably disposed in the second guiding groove  161 . The number of the second guiding post  162  may be two or more, and the number of the second guiding groove  161  is two. As shown in  FIGS. 5 and 6 , the second guiding post  162  can be disposed at two sides of the protecting cover  13  and the second guiding groove  161  can be disposed at two sides of the opening  101 . The driving mechanism  14  can drive the protecting cover  13  to move under the guidance of the second guiding mechanism  16 , which will be described later. 
         [0035]    In the present embodiment, the HUD device further comprises a light source protecting cover  17  (please refer to  FIG. 1 ). The light source protecting cover  17  is pivotally disposed at the housing  10  and the light source protecting cover  17  can cover a light source element (not shown) or uncover to expose the light source element. In particular, the light source protecting cover  17  is an opaque cover plate. The housing  10  is provided with a light source aperture  102 . The light source protecting cover  17  may be pivoted downward to expose the light source aperture  102  (please refer to  FIG. 11 ) such that the light source element is exposed from the light source aperture  102 , and the light source protecting cover  17  may be pivoted upward to cover the light source aperture  102  (please refer to  FIG. 7 ) such that the light source protecting cover  17  covers the light source element to protect the light source element. The light source protecting cover  17  may be connected to the driving mechanism  14 , such that the light source protecting cover  17  may be pivotally disposed at the housing  10  through the driving of the driving mechanism  14 , which will be described later. 
         [0036]    In the present embodiment, the light source protecting cover  17  is of a two-piece design, namely, the light source protecting cover  17  has a first protecting cover  171  and a second protecting cover  172 . The first protecting cover  171  is pivotally disposed on the housing  10 , the second protecting cover  172  is telescopically connected to the first protecting cover  171 , namely, the second protecting cover  172  may be retracted into the first protecting cover  171  or extended out of the first protecting cover  171  with the pivoting of the first protecting cover  171  (please refer to  FIG. 7  and  FIG. 11 ). Of course, the light source protecting cover  17  may be of a one-piece design or also may be a transparent cover plate and is fixedly disposed at the housing  10  and corresponds to the light source element, such that light emitted from the light source element may directly penetrate the light source protecting cover  17 . 
         [0037]    Further, a third guiding mechanism  18  (as shown in  FIG. 7 ) is provided between the light source protecting cover  17  and the housing  10 , for guiding movement of the light source protecting cover  17  at the light source aperture  102 . The construction of the third guiding mechanism  18  is not limited, and may be a combination of a guiding groove with a guiding post, or a combination of a guiding rail with a guiding block, or other existing guiding mechanisms. 
         [0038]    In the present embodiment, the third guiding mechanism  18  comprises a third guiding groove  181  and a third guiding post  182 . The third guiding groove  181  is disposed at the housing  10 . The third guiding groove  181  is disposed at the light source aperture  102  of the housing  10 . The third guiding groove  181  is generally arc-shaped. The third guiding post  182  is disposed at the outer side of the second protecting cover  172  of the light source protecting cover  17 . The third guiding post  182  is slidably disposed in the third guiding groove  181 . The number of the third guiding post  182  may correspond to the number of the third guiding groove  181 . The driving mechanism  14  can drive the light source protecting cover  17  to move under the guidance of the third guiding mechanism  18 , which will be described later. 
         [0039]    The driving mechanism  14  comprises a link  141 , a lever  142  and a driving wheel  143  (as shown in  FIGS. 7 and 8 ). One end of the link  141  is pivotally connected to the protecting cover  13 . One end of the link  141  is pivotally connected to the protecting cover  13  through the first guiding post  162  of the first guiding mechanism  16 , while the other end is engaged with the driving wheel  143 . The link  141  is generally L-shaped. One end of the lever  142  is pivotally connected to the projecting board assembly  12 . One end of the lever  142  is pivotally connected to the holder  121  of the projecting board assembly  12  through a pivot shaft  1211 , while the other end is engaged with the light source protecting cover  17 . The driving wheel  143  may be selectively engaged with the lever  142 . The rotation of the driving wheel  143  may drive the link  141  and the lever  142  to move and thus drive the protecting cover  13 , the projecting board assembly  12  and the light source protecting cover  17  to move, which will be described later. 
         [0040]    In the present embodiment, as shown in  FIGS. 3 and 4 , the driving mechanism  14  is provided with two links  141 ,  141 ′ facing each other, two levers  142 ,  142 ′ facing each other, and two driving wheels  143 ,  143 ′ facing each other. The two links  141 ,  141 ′ are connected to the protecting cover  13  and are engaged with the driving wheels  143 ,  143 ′, respectively, and the two levers  142 ,  142 ′ are connected to the projecting board assembly  12  and the light source protecting cover  17  and can be engaged with the driving wheels  143 ,  143 ′ respectively. Through the two links  141 ,  141 ′, the two levers  142 ,  142 ′ and the two driving wheels  143 ,  143 ′, the movement of the protecting cover  13 , the projecting board assembly  12  and the light source protecting cover  17  can be more stably driven. 
         [0041]    Further, the link  141 , the driving wheel  143 , the lever  142 , and the light source protecting cover  17  may be engaged with each other using engagement mechanisms. The detailed construction of the engagement mechanisms is described in detail below. 
         [0042]    Firstly, a first engagement mechanism  19  (as shown in  FIG. 7 ) is provided between the driving wheel  143  and the link  141  for providing movable engagement of the driving wheel  143  and the link  141 , whereby the driving wheel  143  rotatably drives the link  141  to rotate forward or backward (please refer to  FIG. 7  and  FIG. 9 ). 
         [0043]    Referring to  FIGS. 5 and 6 , in the present embodiment, the first engagement mechanism  19  comprises a first engagement groove  191  and a first engagement pin  192 . The first engagement groove  191  is disposed at the driving wheel  143  and the first engagement pin  192  is disposed at the link  141 . The first engagement groove  191  may be disposed at the outer side of the driving wheel  143 , the first engagement pin  192  may be disposed at one end of the link  141  distal from the protecting cover  13 , and the first engagement pin  192  is slidably disposed in the first engagement groove  191 . The first engagement pin  192  is movable along the first engagement groove  191  for providing movable engagement of the driving wheel  143  and the link  141 , whereby the driving wheel  143  rotatably drives, through the first engagement mechanism  19 , the link  141  to rotate forward or backward (please refer to  FIG. 7  and  FIG. 9 ). 
         [0044]    In particular, the first engagement groove  191  comprises an arc-shaped groove  1911  and an extension groove  1912 , the arc-shaped groove  1911  is located at a periphery of the driving wheel  143 , an end of the extension groove  1912  is in communication with a front end of the arc-shaped groove  1911 , and a front end of the extension groove  1912  extends toward a rotation axis  1431  of the driving wheel  143 . However, the present invention is not limited thereto and the extension groove  1912  may not extend toward the rotation axis  1431  of the driving wheel  143 . That is to say, the shape and angle of the extension groove  1912  may be designed depending on the time required for rotating the driving wheel  143  to open or close the protecting cover  13 , namely, designed depending on the angle of rotation of the driving wheel  143  and thus the distance of sliding of the protecting cover  13  along the curvature of the second guiding groove  161 . The first engagement pin  192  is movable between the extension groove  1912  and the arc-shaped groove  1911 , whereby the link  141  may be rotated forward and backward, namely, the link  141  may be rotated in a direction toward the rotation axis  1431  of the driving wheel  143  (please refer to  FIG. 7 ) and in a direction away from the rotation axis  1431  of the driving wheel  143  (please refer to  FIG. 10 ). Of course, the driving wheel  143  may alternatively rotatably drive the link  141  to move. 
         [0045]    In the present embodiment, the number of the first engagement grooves  191  is two, and they are disposed at the driving wheels  143 ,  143 ′ respectively, and the number of the first engagement pins  192  is two, and they are disposed at the links  141 ,  141 ′ respectively. 
         [0046]    Also, a second engagement mechanism  20  (as shown in  FIG. 7 ) is provided between the driving wheel  143  and the lever  142  for selective engagement of the driving wheel  143  and the lever  142 , whereby the driving wheel  143  rotatably drives the lever  142  to swing upward or downward (please refer to  FIG. 9  and  FIG. 10 ). 
         [0047]    In the present embodiment, the second engagement mechanism  20  comprises a second engagement groove  201  and a second engagement pin  202 , the second engagement groove  201  may be disposed at the outer side of the lever  142  distal from a rotation axis  1421  of the lever  142 , the second engagement groove  201  is generally elongated, and the second engagement pin  202  may be disposed at an inner side of the driving wheel  143  adjacent to the periphery of the driving wheel  143 . The second engagement pin  202  may be selectively moved into the second engagement groove  201  to engage the driving wheel  143  to the lever  142 , whereby the driving wheel  143  rotatably drives the lever  142  to swing upward or downward through the second engagement mechanism  20  (please refer to  FIG. 9  and  FIG. 10 ). 
         [0048]    In the present embodiment, the number of the second engagement grooves  201  is two, and they are disposed at the levers  142 ,  142 ′ respectively, and the number of the second engagement pins  202  is two, and they are disposed at the driving wheels  143 ,  143 ′ respectively. 
         [0049]    In addition, a third engagement mechanism  21  (as shown in  FIG. 8 ) is provided between the lever  142  and the light source protecting cover  17  for providing movable engagement of the lever  142  and the light source protecting cover  17 , such that when the driving wheel  143  drives the lever  142  to swing, the light source protecting cover  17  may also be driven to pivot (please refer to  FIG. 8  and  FIG. 11 ). 
         [0050]    In the present embodiment, the third engagement mechanism  21  comprises a third engagement groove  211  and a third engagement pin  212 , the third engagement groove  211  may be disposed at the inner side of the lever  142  adjacent to the rotation axis  1421  of the lever  142 , the third engagement groove  211  is generally arc-shaped, and the third engagement pin  212  may be disposed at the outer side of the light source protecting cover  17 . An engagement portion  1711  extends from the first protecting cover  171 , the third engagement pin  212  may be disposed at the engagement portion  1711 , and the third engagement pin  212  is slidably disposed in the third engagement groove  211 . The third engagement pin  212  is movable along the third engagement groove  211  for providing movable engagement of the lever  142  and the light source protecting cover  17 , such that the driving wheel  143  may rotatably drive the lever  142  to swing and thus drives the light source protecting cover  17  to pivot through the third engagement mechanism  21  (please refer to  FIG. 8  and  FIG. 11 ). 
         [0051]    In the present embodiment, the number of the third engagement grooves  211  is two, and they are disposed at the inner sides of the levers  142 ,  142 ′ respectively, and the number of the third engagement pins  212  is two, and they are disposed at the outer sides of the light source protecting cover  17  respectively. 
         [0052]    Among the driving wheels  143 ,  143 ′ and the levers  142 ,  142 ′, a positioning mechanism  22  (refer to  FIG. 12 ) may be further disposed between the driving wheel  143 ′ and the lever  142 ′ for positioning the projecting board assembly  12 . 
         [0053]    In the present embodiment, the positioning mechanism  22  comprises a positioning groove  221  and a positioning pin  222 , the positioning groove  222  is disposed at the inner side of the driving wheel  143 ′, and the positioning pin  222  is disposed at the outer side of the lever  142 . The positioning pin  222  may be selectively moved into the positioning groove  221  to engage the driving wheel  143 ′ to the lever  142 ′, such that the projecting board assembly  12  may be positioned by the driving wheel  143 ′ through the positioning mechanism  22 . 
         [0054]    In addition, among the driving wheels  143 ,  143 ′, an angle adjustment mechanism  23  (refer to  FIG. 13 ) may be further disposed between the driving wheel  143  and the projecting board assembly  12  for adjusting an inclination angle of the projecting board assembly  12 , as described in detail below. 
         [0055]    In the present embodiment, the angle adjustment mechanism  23  comprises an adjustment groove  231  and an adjustment pin  232 . The adjustment groove  231  is generally C-shaped, the adjustment groove  231  is disposed at the inner side of the driving wheel  143 , an adjustment portion  1212  extends from one side of the holder  121  of the projecting board assembly  12 , the adjustment portion  1212  is perpendicular to the first guiding post  152 , and the adjustment pin  232  may be disposed at the adjustment portion  1212 . The adjustment pin  232  may be selectively moved into the adjustment groove  231  to engage the driving wheel  143  with the projecting board assembly  12 , such that the driving wheel  143  rotatably drives the adjustment groove  231  and thus the adjustment pin  232 , thereby driving the projecting board assembly  12  to adjust the inclination angle of the projecting board assembly  12  (please refer to  FIG. 13  and  FIG. 14 ). 
         [0056]    More particular, a retaining groove  153  is also provided at a front end of the first guiding groove  151 , the retaining groove  153  is generally perpendicular to the first guiding groove  151 , the first guiding post  152  may slide into the retaining groove  153  along the first guiding groove  151  and may slide in the retaining groove  153  with the movement of the adjustment pin  232 , so as to limit, through the retaining groove  153 , the sliding travel of the first guiding post  152 , thereby limiting the inclination angle of the projecting board assembly  12  (please refer to  FIG. 13  and  FIG. 14 ). 
         [0057]    Referring to  FIG. 7  to  FIG. 14 , operation of the HUD device of the present invention is described below, starting from the position as shown in  FIG. 7  and  FIG. 8 . 
         [0058]    As shown in  FIG. 7  and  FIG. 8 , the protecting cover  13  is in a closed position A (or referred to as a first closed position), which is located at the opening  101  of the housing  10 ; the projecting board assembly  12  is in a storing position C, which is located below the opening  101  of the housing  10 ; and the light source protecting cover  17  is in a closed position E (or referred to as a second closed position), which is located at the light source aperture  102  of the housing  10 . 
         [0059]    Referring to  FIG. 7  and  FIG. 9 , when the driving wheel  143  rotates in a direction (for example, in a clockwise direction), the driving wheel  143  drives the link  141  to rotate, such that the protecting cover  13  is moved from the closed position A to an open position B, which is located distal from the opening  101  of the housing  10 . In particular, the driving wheel  143  and the link  141  are linked through the first engagement mechanism  19 , namely, when the driving wheel  143  rotates in the direction, the first engagement pin  192  is moved from the extension groove  1912  to the arc-shaped groove  1911  with the rotation of the driving wheel  143 , whereby the link  141  rotates in a direction away from the driving wheel  143  to drive the protecting cover  13  to move in a direction away from the opening  101 , such that the projecting board  122  of the projecting board assembly  12  is exposed at the opening  101 . 
         [0060]    Then, referring to  FIG. 10  and  FIG. 11 , when the driving wheel  143  continues to rotate in the direction, the driving wheel  143  drives the lever  142  to swing upward, such that the projecting board assembly  12  is moved from the storing position C to a displaying position D, which is located outside the housing  10 . In particular, the driving wheel  143  and the lever  142  are linked through the second engagement mechanism  20 , namely, when the driving wheel  143  continues to rotate in the direction, the second engagement pin  202  is moved into the second engagement groove  201  with the rotation of the driving wheel  143 , to engage the driving wheel  143  to the lever  142  and thus drive the lever  142  to swing upward, whereby the projecting board assembly  12  is raised by the lever  142  to cause the projecting board assembly  12  to slide upward and extend outward through the opening  101  to be outside the housing  10  (as shown in  FIG. 11 ). 
         [0061]    Meanwhile, referring to  FIG. 8  and  FIG. 11 , the light source protecting cover  17  is pivoted from the closed position E to an open position F, which is located distal from the light source aperture  102  of the housing  10 . In particular, the lever  142  and the light source protecting cover  17  are linked through the third engagement mechanism  21 , namely, when the driving wheel  143  drives the lever  142  to swing upward, the third engagement pin  212  is moved downward from the front end to the end of the third engagement groove  211  along with the upward swinging of the lever  142 , such that the light source protecting cover  17  is pivoted downward to expose the light source aperture  102  (as shown in  FIG. 11 ). 
         [0062]    Then, as shown in  FIG. 12  (for conciseness, only the guiding base  11 , the projecting board assembly  12 , the lever  142 ′, the driving wheel  143 ′, the second engagement mechanism  20 , and the positioning mechanism  22  are shown in the schematic view), when the projecting board assembly  12  reaches the displaying position D, the second engagement pin  202  is detached from the second engagement groove  201 , and at this time, the projecting board assembly  12  is positioned at the displaying position D by the driving wheel  143 ′ and the lever  142 ′ through the positioning mechanism  22 . That is to say, when the second engagement pin  202  is detached from the second engagement groove  201 , the positioning pin  222  has been moved into the positioning groove  221 , such that the driving wheel  143 ′ may support the lever  142 ′ and the lever  142 ′ does not swing downward because of the detachment of the second engagement pin  202 , thereby positioning the projecting board assembly  12  at the displaying position D. 
         [0063]    In addition, as shown in  FIG. 13  and  FIG. 14  (for conciseness, only the guiding base  11 , the projecting board assembly  12 , the lever  142 , the driving wheel  143 , the first guiding mechanism  15 , the light source protecting cover  17 , and the second engagement mechanism  20  are shown in the schematic views), when the projecting board assembly  12  is at the displaying position D, the driving wheel  143  and the projecting board assembly  12  are linked through the angle adjustment mechanism  23  to adjust the inclination angle of the projecting board assembly  12  at the displaying position D. That is to say, the adjustment pin  232  is moved into the adjustment groove  231  to engage the driving wheel  143  with the projecting board assembly  12 , whereby when the driving wheel  143  continues to rotate (as shown in  FIG. 14 ), the adjustment pin  232  is driven by the adjustment groove  231 , thereby driving the holder  121  of the projecting board assembly  12 , and at this time, the holder  121  of the projecting board assembly  12  is pivoted about the pivot shaft  1211  to enable the inclination angle of the projecting board  122  to be adjusted to a suitable viewing position, and the first guiding post  152  is slid into the retaining groove  153  to limit the inclination angle of the projecting board assembly  12 , thereby avoiding an overly large inclination angle. 
         [0064]    It should be understood that, when the driving wheel  143  rotates in another direction (in a counterclockwise direction), the driving wheel  143  may drive the lever  142  to swing downward, such that the projecting board assembly  12  is moved from the displaying position D to the storing position C and the light source protecting cover  17  is pivoted from the open position F to the closed position E, and the driving wheel  143  may drive the link  141  to rotate, such that the protecting cover  13  is moved from the open position B to the closed position A. 
         [0065]    The projecting board assembly  12  of the present invention comprises the holder  121  and the projecting board  122 . The protecting cover  13  can cover the projecting board  122  of the projecting board assembly  12 , thereby achieving the effect of protecting the projecting board  122  to prevent the projecting board  122  from being exposed to sunshine or adhered with dust. In addition, the rotation of the driving wheel  143  may drive the link  141  and the lever  142  to move and thus drive the protecting cover  13  and the projecting board assembly  12  to move. As such, only one driving wheel  143  is required for driving all the objects, and thus the arrangement of the driving mechanism  14  is relatively easy, so as to simplify the structure and reduce cost. 
         [0066]    Furthermore, according to the present invention, the light source protecting cover  17  is further disposed on the housing  10 , and the other end of the lever  142  is engaged with the light source protecting cover  17 , such that the rotation of the driving wheel  143  may drive the lever  142  to move and thus drive the light source protecting cover  17  to move. Thus, no other driving mechanisms are required for driving the light source protecting cover  17 , which also simplifies the structure and reduces cost. 
         [0067]    However, the description above is only preferred embodiments of the present invention and is not intended to limit the scope of the present invention. All equivalent changes made according to the specification and drawings of the present invention falls within the scope of the present invention.