Abstract:
The present invention provides a display device that can increase the apparent number of pixels. The display device includes a display panel and an optical path changing device. The optical path changing device includes a first lens and an optical path controller between the display panel and the first lens to control optical paths of respective light rays from the plurality of pixels in the display panel. The first lens has a light receiving inner surface having a plurality of inner lens surfaces and a light exit outer surface having a plurality of outer lens surfaces. The inner lens surfaces and the outer lens surfaces of the first lens are configured such that light from the display panel that has entered a prescribed portion of the inner lens surfaces exits one outer lens surface in a prescribed incident angle exits from a corresponding one of the outer lens surfaces to reach the viewer.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a display device, and more particularly to a display device provided with an optical path changing device that changes the paths taken by light emitted from pixels formed in a display panel. 
       BACKGROUND ART 
       [0002]    In recent years, display devices have been designed to feature increasingly high resolutions. As the pursuit of ever higher resolutions continues, the number of pixels used in display panels increases accordingly. As the number of pixels in display panels increases, components such as the pixel electrodes and wiring lines must be patterned with increasingly high precision. This increases the difficulty of patterning these components such as pixel electrodes and wiring lines. 
         [0003]    Moreover, as this pursuit of increasingly high resolutions continues, pixel aperture ratios become increasingly small. In liquid crystal display devices, smaller pixel aperture ratios make it more difficult for light from the backlight to pass through the display panel. As a result, the brightness of the light from the backlight must be increased. This means that as liquid crystal display devices continue to be designed with higher resolutions, power consumption continues to increase accordingly. 
       SUMMARY OF THE INVENTION 
       [0004]    An object of the present invention is to provide a display device that can increase the apparent number of pixels. 
         [0005]    A display device according to one embodiment of the present invention includes: a display panel including a plurality of pixels formed side by side in a prescribed direction; and an optical path changing device that is arranged closer to a viewer&#39;s side than the display panel and that changes paths taken by light emitted from the pixels, wherein the optical path changing device includes: a first lens; a plurality of second lenses arranged side by side in the prescribed direction and disposed closer to the display panel than the first lens; and an emission direction control device that changes a direction in which light from the pixels that has entered the second lenses is emitted therefrom, wherein the first lens includes: a plurality of inner lens surfaces formed side by side in the prescribed direction on a display panel side; and pairs of outer lens surfaces that are formed side by side in the prescribed direction on the viewer&#39;s side, overlapping each of the inner lens surfaces when the display panel is viewed from a front side, wherein light from the pixels that has entered the inner lens surface exits one of the outer lens surfaces among the respective pairs of outer lens surfaces in accordance with a direction in which the light from the pixels that has entered the second lenses is emitted therefrom. 
         [0006]    The display device according to an embodiment of the present invention can increase the apparent number of pixels. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  schematically illustrates an example configuration of a display device according to Embodiment 1 of the present invention. 
           [0008]      FIG. 2  is a plan view illustrating an optical path changing device of the display device shown in  FIG. 1 . 
           [0009]      FIG. 3A  schematically illustrates the paths taken by light emitted from pixels. 
           [0010]      FIG. 3B  schematically illustrates the paths taken by light emitted from pixels when the light takes different paths than those shown in  FIG. 3A . 
           [0011]      FIG. 4  schematically illustrates another mechanism used to move a second lens. 
           [0012]      FIG. 5  schematically illustrates an example configuration of a display device according to Embodiment 2 of the present invention. 
           [0013]      FIG. 6  is a plan view illustrating an optical path changing device of the display device shown in  FIG. 5 . 
           [0014]      FIG. 7A  schematically illustrates the paths taken by light emitted from pixels. 
           [0015]      FIG. 7B  schematically illustrates the paths taken by light emitted from pixels when the light takes different paths than those shown in  FIG. 7A . 
           [0016]      FIG. 8  schematically illustrates an example configuration of a display device according to Embodiment 3 of the present invention. 
           [0017]      FIG. 9  is an enlarged cross-sectional view of a portion of  FIG. 8 . 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0018]    A display device according to one embodiment of the present invention includes: a display panel including a plurality of pixels formed side by side in a prescribed direction; and an optical path changing device that is arranged closer to a viewer&#39;s side than the display panel and that changes paths taken by light emitted from the pixels, wherein the optical path changing device includes: a first lens; a plurality of second lenses arranged side by side in the prescribed direction and disposed closer to the display panel than the first lens; and an emission direction control device that changes a direction in which light from the pixels that has entered the second lenses is emitted therefrom, wherein the first lens includes: a plurality of inner lens surfaces formed side by side in the prescribed direction on a display panel side; and pairs of outer lens surfaces that are formed side by side in the prescribed direction on the viewer&#39;s side, overlapping each of the inner lens surfaces when the display panel is viewed from a front side, wherein light from the pixels that has entered the inner lens surface exits one of the outer lens surfaces among the respective pairs of outer lens surfaces in accordance with a direction in which the light from the pixels that has entered the second lenses is emitted therefrom. 
         [0019]    In a first configuration of an embodiment of the present invention, the light from pixels that enters the inner lens surfaces exits one outer lens surface of each pair of outer lens surfaces according to the direction in which the light from the pixels that enters the second lenses is emitted therefrom. As a result, this configuration can increase the apparent number of pixels in the prescribed direction. 
         [0020]    In a second configuration of an embodiment of the present invention, the second lenses of the first configuration are configured to be rotatable between a first position and a second position differing from the first position, and a direction in which light from the pixels is focused when the second lenses are in the first position differs from a direction in which light from the pixels is focused when the second lenses are in the second position. 
         [0021]    This makes it possible to change the direction in which light from the pixels that enters the second lenses is emitted therefrom. 
         [0022]    In a third configuration of an embodiment of the present invention, the second lenses are configured so as to be moveable laterally between a first position and a second position that differs from the first position, and a direction in which light from the pixels is focused when the second lenses are in the first position differs from a direction in which light from the pixels is focused when the second lenses are in the second position. 
         [0023]    This makes it possible to change the direction in which light from the pixels that enters the second lenses is emitted therefrom. 
         [0024]    In a fourth configuration of an embodiment of the present invention, the second lens of the first configuration includes: a substrate facing the first lens; a plurality of trenches arranged side by side in the prescribed direction on a surface of the substrate facing the first lens; a hydrophobic dielectric film formed along inner surfaces of the trenches; electrodes that are covered by the hydrophobic dielectric film, one of the electrodes being arranged on each wall among a pair of walls of each trench; an oil film housed inside the trenches and arranged in contact with the hydrophobic dielectric film; and a liquid that covers the oil film and is separated therefrom, wherein the emission direction control device changes voltages applied to the electrodes. 
         [0025]    The shape of the interface between the oil film and the liquid is changed by changing the voltages applied to the first electrodes. This makes it possible to change the direction in which light from the pixels that enters the second lens member is emitted therefrom. 
         [0026]    In a fifth configuration of an embodiment of the present invention, the pixels of any one of the first to fourth configurations each include a plurality of sub-pixels that respectively emit light of different colors and that are arranged side by side in the prescribed direction, and wherein each of the outer lens surfaces among the pairs of outer lens surfaces includes a plurality of first outer lens surfaces, each of the first outer lens surfaces corresponding to one of the sub-pixels. 
         [0027]    Next, embodiments of the present invention will be described in more detail with reference to figures. The same reference characters are used for components that are the same or equivalent in each of the figures, and duplicate descriptions of such components are omitted. Moreover, in the figures referenced below, configurations of the present invention are depicted in a simplified or schematic style for purposes of explanation. Some components are not depicted in the figures. Furthermore, the dimensional proportions depicted between the components in the figures are not necessarily the actual dimensional proportions between those components. 
       Embodiment 1 
       [0028]      FIG. 1  shows a display device  10  according to Embodiment 1 of the present invention. The display device  10  includes a display panel  12  and an optical path changing device  14 . 
         [0029]    &lt;Display Panel&gt; 
         [0030]    The display panel  12  includes a plurality of pixels  16  arranged side by side in a left-to-right direction (that is, the horizontal direction relative to the display panel  12 ). Each pixel  16  includes a plurality of sub-pixels  16 R,  16 G, and  16 B. The plurality of sub-pixels  16 R,  16 B, and  16 B are arranged side by side in the same direction in which the plurality of pixels  16  are arranged. Each sub-pixel in the plurality of sub-pixels  16 R,  16 G, and  16 B emits light of a different color. In the present embodiment, the sub-pixel  16 R emits red light, the sub-pixel  16 G emits green light, and the sub-pixel  16 B emits blue light. 
         [0031]    The display panel  12  is not particularly limited in any way. The display panel  12  may be a liquid crystal panel, an organic electroluminescent panel, or a plasma display panel, for example. When the display panel  12  is a liquid crystal panel, the display device  10  also includes a backlight (not shown in the figures). In such a configuration of the display device  10 , the pixels in the liquid crystal panel emit light that originates from the backlight and passes through the pixels. 
         [0032]    &lt;Optical Path Changing Device&gt; 
         [0033]    The optical path changing device  14  is arranged nearer to the viewer than the display panel  12  and changes the paths taken by light emitted from the pixels  16 . The optical path changing device  14  includes a first lens  18 , a plurality of second lenses  20 , and an emission direction control device  22  (shown in  FIG. 2 ). 
         [0034]    &lt;First Lens&gt; 
         [0035]    The first lens  18  has a plurality of inner lens surfaces  24  and a plurality of pairs of outer lens surfaces  26 R and  26 L. 
         [0036]    The plurality of inner lens surfaces  24  are formed on the display panel  12  side of the first lens  18  and are arranged side by side in the horizontal direction. Each inner lens surface  24  is a concave lens surface that opens towards the display panel  12 . When viewing the display panel  12  from the front side, the boundaries B 1  between adjacent inner lens surfaces  24  are positioned directly over the centers C 1  of the pixels  16  in the horizontal direction. Therefore, in the present embodiment, when viewing the display panel  12  from the front side, the boundaries B 1  are positioned directly over the centers C 2  of the sub-pixels  16 G in the horizontal direction. The length of each inner lens surface  24  in the horizontal direction is equal to the pixel pitch. 
         [0037]    The plurality of pairs of outer lens surfaces  26 R and  26 L are formed on the viewer side of the first lens  18  and are arranged side by side in the horizontal direction. When viewing the display panel  12  from the front side, each of the plurality of inner lens surfaces  24  overlaps with one pair of the outer lens surfaces  26 R and  26 L. In other words, the outer lens surfaces  26 R and  26 L are arranged alternately in the horizontal direction on the viewer side of the first lens  18 . 
         [0038]    When viewing the display panel  12  from the front side, the boundary B 2  between the outer lens surface  26 R and the outer lens surface  26 L in one pair of outer lens surfaces  26 R and  26 L that overlaps with one of the inner lens surfaces  24  is positioned directly over the center C 3  of that inner lens surface  24  in the horizontal direction. When viewing the display panel  12  from the front side, the boundary between one outer lens surface  26 R that overlaps with one of two adjacent inner lens surfaces  24  and one outer lens surface  26 L that overlaps with the other of the two adjacent inner lens surfaces  24  is positioned directly on the boundary B 1 . 
         [0039]    Each outer lens surface  26 R includes a plurality of first outer lens surfaces  28 RR,  28 GR, and  28 BR that correspond to the sub-pixels  16 R,  16 G, and  16 B, respectively, of one of the pixels  16 . The plurality of first outer lens surfaces  26 RR,  28 GR, and  28 BR are arranged side by side in the horizontal direction. The plurality of first outer lens surfaces  26 RR,  28 GR, and  28 BR are arranged side by side in the same order in which the plurality of sub-pixels  16 R,  16 G, and  16 B are arranged. Each of the plurality of first outer lens surfaces  26 RR,  28 GR, and  28 BR is a concave lens surface that opens towards the viewer side. 
         [0040]    Each outer lens surface  26 L includes a plurality of first outer lens surfaces  28 RL,  28 GL, and  28 BL that correspond to the sub-pixels  16 R,  16 G, and  16 B, respectively, of one of the pixels  16 . The plurality of first outer lens surfaces  26 RL,  28 GL, and  28 BL are arranged side by side in the horizontal direction. The plurality of first outer lens surfaces  26 RL,  28 GL, and  28 BL are arranged side by side in the same order in which the plurality of sub-pixels  16 R,  16 G, and  16 B are arranged. Each of the plurality of first outer lens surfaces  26 RL,  28 GL, and  28 BL is a concave lens surface that opens towards the viewer side. 
         [0041]    &lt;Second Lenses&gt; 
         [0042]    The plurality of second lenses  20  are arranged side by side in the horizontal direction and are nearer to the display panel  12  than is the first lens  18 . In the present embodiment, there is one second lens  20  for each pixel  16 . In other words, the number of second lenses  20  is the same as the number pixels  16  that are arranged side by side in the horizontal direction. 
         [0043]    When viewing the display panel  12  from the front side, the centers C 4  of each second lens  20  in the horizontal direction are positioned directly over the centers C 1  of each pixel  16  in the horizontal direction and align with the boundaries B 1  between adjacent inner lens surfaces  24 . 
         [0044]    Each second lens  20  is a prism-shaped member having a prescribed cross-sectional shape. The cross-sectional shape of each second lens  20  is symmetric around a reference line L 1  that runs in the horizontal direction. Each second lens  20  decreases in thickness moving from one side of the horizontal direction to the other. Each second lens  20  has two convex lens surfaces (a light-entering surface into which light enters and a light-exiting surface through which light exits). As a result, light that enters each second lens  20  is concentrated in a prescribed direction (that is, towards the thicker edge of the second lens  20 ). The length of each second lens  20  in the horizontal direction is equal to the length of each inner lens surface  24  in the horizontal direction. 
         [0045]    Each of the second lenses  20  is arranged having the same orientation. In other words, the thicker edge of one second lens  20  neighbors the thinner edge of the adjacent second lens  20 . 
         [0046]    &lt;Emission Direction Control Device&gt; 
         [0047]    Next, the emission direction control device  22  will be described with reference to  FIG. 2 . The emission direction control device  22  includes a plurality of motors  34 . The motors  34  are driven by a driver circuit (not shown in the figure). The driving force of each motor  34  is transmitted to an axle  30 A provided on one lengthwise end of each second lens  20 . This causes each second lens  20  to rotate around the centerline axis of the corresponding axle  30 A. Moreover, an axle  30 B is formed on the other lengthwise end of each second lens  20 . The axles  30 B are rotatably connected to a supporting member  32  formed on the viewer-side surface of the display panel  12 . 
         [0048]    &lt;Operation of the Optical Path Changing Device&gt; 
         [0049]    Next, operation of the optical path changing device  14  will be described with reference to  FIGS. 3A and 3B . When the second lenses  20  are in the state shown in  FIG. 3A , light emitted from the sub-pixels  16 R,  16 G, and  16 B takes the paths described below. 
         [0050]    Light emitted from the sub-pixel  16 R enters the respective second lens  20  and exits proceeding towards the left inner lens surface  24  of the two inner lens surfaces  24  that overlap with that second lens  20  when the display panel  12  is viewed from the front side. The light emitted from the sub-pixel  16 R then enters that inner lens surface  24  and exits from the first outer lens surface  28 RR that overlaps with that inner lens surface  24  when the display panel  12  is viewed from the front side. 
         [0051]    Light emitted from the sub-pixel  16 G enters the same second lens  20  and exits proceeding towards the abovementioned left inner lens surface  24 . The light emitted from the sub-pixel  16 G then enters that inner lens surface  24  and exits from the first outer lens surface  28 GR that overlaps with that inner lens surface  24  when the display panel  12  is viewed from the front side. 
         [0052]    Light emitted from the sub-pixel  16 B enters the same second lens  20  and exits proceeding towards the abovementioned left inner lens surface  24 . The light emitted from the sub-pixel  16 B then enters that inner lens surface  24  and exits from the first outer lens surface  28 BR that overlaps with that inner lens surface  24  when the display panel  12  is viewed from the front side. 
         [0053]    When the rotational force of each of the motors  34  is transmitted to the respective axles  30 A, each of the second lenses  20  rotates around the centerline axis of the respective axle  30 A. This rotates the second lenses  20  into the state shown in  FIG. 3B . In the state shown in  FIG. 3B , the second lenses  20  are rotated one half of a full rotation from the state shown in  FIG. 3A . When the second lenses  20  are in the state shown in  FIG. 3B , light emitted from the sub-pixels  16 R,  16 G, and  16 B takes the paths described below. 
         [0054]    Light emitted from the sub-pixel  16 R enters the respective second lens  20  and exits proceeding towards the right inner lens surface  24  of the two inner lens surfaces  24  that overlap with that second lens  20  when the display panel  12  is viewed from the front side. The light emitted from the sub-pixel  16 R then enters that inner lens surface  24  and exits from the first outer lens surface  28 RL that overlaps with that inner lens surface  24  when the display panel  12  is viewed from the front side. 
         [0055]    Light emitted from the sub-pixel  16 G enters the same second lens  20  and exits proceeding towards the abovementioned right inner lens surface  24 . The light emitted from the sub-pixel  16 G then enters that inner lens surface  24  and exits from the first outer lens surface  28 GL that overlaps with that inner lens surface  24  when the display panel  12  is viewed from the front side. 
         [0056]    Light emitted from the sub-pixel  16 B enters the same second lens  20  and exits proceeding towards the abovementioned right inner lens surface  24 . The light emitted from the sub-pixel  16 B then enters that right inner lens surface  24  and exits from the first outer lens surface  28 BL that overlaps with that inner lens surface  24  when the display panel  12  is viewed from the front side. 
         [0057]    As described above, as the second lenses  20  are rotated, the light emitted from the sub-pixels  16 R,  16 G, and  16 B exits alternately from the outer lens surfaces  26 R and the outer lens surfaces  26 L. Therefore, by switching the image displayed by the display panel  12  back and forth between an image formed from light emitted from the outer lens surfaces  26 R and an image formed from light emitted from the outer lens surfaces  26 L, the apparent number of pixels that the user perceives in the horizontal direction can be increased by a factor of two. 
         [0058]    It should be noted that the timing with which each second lens  20  is rotated by half of a full rotation and the timing with which the image displayed by the display panel  12  is switched must be synchronized. Moreover, all of the second lenses  20  must be rotated by half of a full rotation at the same time. 
         [0059]    Furthermore, light emitted from the pixels  16  is not separated into individual colors in the display device  10 , thereby reducing the occurrence of color breaking effects. 
         [0060]    &lt;Example Driving Method for the Second Lenses&gt; 
         [0061]    As shown in  FIG. 4 , each second lens  20  has two lens surfaces  21 A and  21 B. One lens surface is positively charged, and the other lens surface is negatively charged, for example. The second lenses  20  are then arranged between a pair of electrodes (not shown in the figure). The polarity of the charge applied to each electrode is then changed to create repulsive forces between the electrodes and the second lenses  20 . These repulsive forces cause the second lenses  20  to rotate. The second lenses  20  may be driven using this driving method. 
       Embodiment 2 
       [0062]    Next, a display device  10 A according to Embodiment 2 of the present invention will be described with reference to  FIGS. 5 and 6 . The display device  10 A includes an optical path changing device  14 A instead of the optical path changing device  14 . The second lenses and emission direction control device of the optical path changing device  14 A differ from those used in the optical path changing device  14 . 
         [0063]    As shown in  FIG. 5 , in the present embodiment, the second lenses  20  are replaced by second lenses  20 A. Each second lens  20 A is a prism-shaped member having a prescribed cross-sectional shape. The cross-sectional shape of the second lenses  20 A is symmetric around a reference line L 2  that runs in the horizontal direction and around a reference line L 3  that runs in the vertical direction. Each second lens  20 A has two convex lens surfaces (a light-entering surface into which light enters and a light-exiting surface through which light exits). As a result, light that enters each second lens  20 A is concentrated in a prescribed direction (that is, towards the center of the respective second lens  20 A in the horizontal direction). The length of each second lens  20 A in the horizontal direction is equal to two times the length of each inner lens surface  24  in the horizontal direction. In other words, the length of each second lens  20 A in the horizontal direction is equal to two times the length of each pixel  16  in the horizontal direction. 
         [0064]    As shown in  FIG. 6 , in the present embodiment, the emission direction control device  22  is replaced by an emission direction control device  22 A. The emission direction control device  22 A includes a pair of charging members  40 A and  40 B and a plurality of springs  46 . The charging member  40 A is fixed to a pair of supporting members  42 . Each supporting member  42  runs in the horizontal direction relative to the display panel  12  (that is, the left-to-right direction in  FIG. 6 ), and the pair of supporting members  42  connect together the plurality of second lenses  20 A that are arranged side by side in the horizontal direction relative to the display panel  12 . More specifically, one of the supporting members  42  supports the lengthwise ends of the second lenses  20 A on one lengthwise side thereof, and the other supporting member  42  supports the lengthwise ends of the second lenses  20 A on the other lengthwise side thereof (where the lengthwise direction is parallel to the vertical direction relative to the display panel  12  and runs in the vertical direction in  FIG. 6 ). Each supporting member  42  is housed in a guide member  44  and can therefore move in the horizontal direction. The pair of charging members  40 A and  40 B are connected together by the springs  46 . The charging member  40 A is charged positively. The charging member  40 B can be charged negatively or be put in a neutral state in which the charging member  40 B is not charged positively or negatively. A driver circuit (not shown in the figure) can be used to achieve the charged state and the neutral state in the charging member  40 B, for example. More specifically, a negative voltage can be applied to the charging member  40 B to charge the charging member  40 B negatively, and the charging member  40 B can be grounded to achieve the neutral state in which the charging member  40 B is not charged positively or negatively, for example. 
         [0065]    In the emission direction control device  22 A, negatively charging the charging member  40 B creates an attractive force between the pair of charging members  40 A and  40 B and causes the charging member  40 A to move towards the charging member  40 B. Conversely, when the charging member  40 B is in the neutral state, the charging member  40 A moves away from the charging member  40 B due to the energy stored in the springs  42 . This causes the second lenses  22 A to move back and forth in the horizontal direction. 
         [0066]    &lt;Operation of the Optical Path Changing Device&gt; 
         [0067]    Next, operation of the optical path changing device  14 A will be described with reference to  FIGS. 7A and 7B . When the second lenses  20 A are in the state shown in  FIG. 3A  (that is, when the centers C 4 A of each second lens  20 A in the horizontal direction are positioned directly over the boundaries B 3  between adjacent pixels  16 ), light emitted from the sub-pixels  16 R,  16 G, and  16 B takes the paths described below. 
         [0068]    Light emitted from the sub-pixel  16 R of the right pixel  16  of two adjacent pixels  16  enters the respective second lens  20 A and exits proceeding towards the inner lens surface  24  that overlaps with the abovementioned boundary B 3  when the display panel  12  is viewed from the front side. The light emitted from the sub-pixel  16 R then enters that inner lens surface  24  and exits from the first outer lens surface  28 RR that overlaps with that inner lens surface  24  when the display panel  12  is viewed from the front side. 
         [0069]    Light emitted from the sub-pixel  16 G of the abovementioned right pixel  16  enters the same second lens  20 A and exits proceeding towards the inner lens surface  24  that overlaps with the abovementioned boundary B 3  when the display panel  12  is viewed from the front side. The light emitted from the sub-pixel  16 G then enters that inner lens surface  24  and exits from the first outer lens surface  28 GR that overlaps with that inner lens surface  24  when the display panel  12  is viewed from the front side. 
         [0070]    Light emitted from the sub-pixel  16 B of the abovementioned right pixel  16  enters the same second lens  20 A and exits proceeding towards the inner lens surface  24  that overlaps with the abovementioned boundary B 3  when the display panel  12  is viewed from the front side. The light emitted from the sub-pixel  16 B then enters that inner lens surface  24  and exits from the first outer lens surface  28 BR that overlaps with that inner lens surface  24  when the display panel  12  is viewed from the front side. 
         [0071]    Light emitted from the sub-pixel  16 R of the left pixel  16  of two adjacent pixels  16  enters the same second lens  20 A and exits proceeding towards the inner lens surface  24  that overlaps with the abovementioned boundary B 3  when the display panel  12  is viewed from the front side. The light emitted from the sub-pixel  16 R then enters that inner lens surface  24  and exits from the first outer lens surface  28 RL that overlaps with that inner lens surface  24  when the display panel  12  is viewed from the front side. 
         [0072]    Light emitted from the sub-pixel  16 G of the abovementioned left pixel  16  enters the same second lens  20 A and exits proceeding towards the inner lens surface  24  that overlaps with the abovementioned boundary B 3  when the display panel  12  is viewed from the front side. The light emitted from the sub-pixel  16 G then enters that inner lens surface  24  and exits from the first outer lens surface  28 GL that overlaps with that inner lens surface  24  when the display panel  12  is viewed from the front side. 
         [0073]    Light emitted from the sub-pixel  16 B of the abovementioned left pixel  16  enters the same second lens  20 A and exits proceeding towards the inner lens surface  24  that overlaps with the abovementioned boundary B 3  when the display panel  12  is viewed from the front side. The light emitted from the sub-pixel  16 B then enters that inner lens surface  24  and exits from the first outer lens surface  28 BL that overlaps with that inner lens surface  24  when the display panel  12  is viewed from the front side. 
         [0074]    The second lenses  20 A then move in the horizontal direction due to an attractive force between the pair of charging members  40 A and  40 B. This moves the second lenses  20 A into the state shown in  FIG. 7B . In the state shown in  FIG. 7B , the second lenses  20 A are moved by a distance equal to the length of one pixel in the horizontal direction from the state shown in  FIG. 7A . In contrast with the state shown in  FIG. 7A , in the state shown in  FIG. 7B  the boundaries B 3  align with the boundaries between adjacent second lenses  20 A. When the second lenses  20 A are in the state shown in  FIG. 7B , light emitted from the sub-pixels  16 R,  16 G, and  16 B takes the paths described below. 
         [0075]    Light emitted from the sub-pixel  16 R of the right pixel  16  of the two adjacent pixels  16  enters the second lens  20 A positioned to the right of the boundary B 3  and exits proceeding towards the inner lens surface  24  to the right of the inner lens surface  24  that overlaps with the abovementioned boundary B 3  when the display panel  12  is viewed from the front side. The light emitted from the sub-pixel  16 R then enters that inner lens surface  24  and exits from the first outer lens surface  28 RL that overlaps with that inner lens surface  24  when the display panel  12  is viewed from the front side. 
         [0076]    Light emitted from the sub-pixel  16 G of the abovementioned right pixel  16  enters the second lens  20 A positioned to the right of the boundary B 3  and exits proceeding towards the inner lens surface  24  to the right of the inner lens surface  24  that overlaps with the abovementioned boundary B 3  when the display panel  12  is viewed from the front side. The light emitted from the sub-pixel  16 G then enters that inner lens surface  24  and exits from the first outer lens surface  28 GL that overlaps with that inner lens surface  24  when the display panel  12  is viewed from the front side. 
         [0077]    Light emitted from the sub-pixel  16 B of the abovementioned right pixel  16  enters the second lens  20 A positioned to the right of the boundary B 3  and exits proceeding towards the inner lens surface  24  to the right of the inner lens surface  24  that overlaps with the abovementioned boundary B 3  when the display panel  12  is viewed from the front side. The light emitted from the sub-pixel  16 B then enters that inner lens surface  24  and exits from the first outer lens surface  28 BL that overlaps with that inner lens surface  24  when the display panel  12  is viewed from the front side. 
         [0078]    Light emitted from the sub-pixel  16 R of the left pixel  16  of the two adjacent pixels  16  enters the second lens  20 A positioned to the left of the boundary B 3  and exits proceeding towards the inner lens surface  24  to the left of the inner lens surface  24  that overlaps with the abovementioned boundary B 3  when the display panel  12  is viewed from the front side. The light emitted from the sub-pixel  16 R then enters that inner lens surface  24  and exits from the first outer lens surface  28 RR that overlaps with that inner lens surface  24  when the display panel  12  is viewed from the front side. 
         [0079]    Light emitted from the sub-pixel  16 G of the abovementioned left pixel  16  enters the second lens  20 A positioned to the left of the boundary B 3  and exits proceeding towards the inner lens surface  24  to the left of the inner lens surface  24  that overlaps with the abovementioned boundary B 3  when the display panel  12  is viewed from the front side. The light emitted from the sub-pixel  16 G then enters that inner lens surface  24  and exits from the first outer lens surface  28 GR that overlaps with that inner lens surface  24  when the display panel  12  is viewed from the front side. 
         [0080]    Light emitted from the sub-pixel  16 B of the abovementioned left pixel  16  enters the second lens  20 A positioned to the left of the boundary B 3  and exits proceeding towards the inner lens surface  24  to the left of the inner lens surface  24  that overlaps with the abovementioned boundary B 3  when the display panel  12  is viewed from the front side. The light emitted from the sub-pixel  16 B then enters that inner lens surface  24  and exits from the first outer lens surface  28 BR that overlaps with that inner lens surface  24  when the display panel  12  is viewed from the front side. 
         [0081]    As described above, as the second lenses  20 A move, the light emitted from the sub-pixels  16 R,  16 G, and  16 B exits alternately from the outer lens surfaces  26 R and the outer lens surfaces  26 L. Therefore, by switching the image displayed by the display panel  12  back and forth between an image formed from light emitted from the outer lens surfaces  26 R and an image formed from light emitted from the outer lens surfaces  26 L, the apparent number of pixels that the user perceives in the horizontal direction can be increased by a factor of two. 
         [0082]    It should be noted that the timing with which each second lens  20 A moves by a distance equal to the length of one pixel and the timing with which the image displayed by the display panel  12  is switched must be synchronized. 
       Embodiment 3 
       [0083]    Next, a display device  10 B according to Embodiment 3 of the present invention will be described with reference to  FIGS. 8 and 9 . The display device  10 B includes an optical path changing device  14 B instead of the optical path changing device  14 . The second lenses and emission direction control device of the optical path changing device  14 B differ from those used in the optical path changing device  14 . 
         [0084]    As shown in  FIG. 8 , in the present embodiment, the second lenses  20  are replaced by a second lens member  20 B. As shown in  FIGS. 8 and 9 , the second lens member  20 B includes a substrate  50 , a plurality of trenches  52 , a hydrophobic dielectric film  54 , a plurality of electrodes  56 , an oil film  58 , and a liquid  60 . The substrate  50  is arranged facing a first lens  18 . The plurality of trenches  52  are formed side by side in the horizontal direction on the surface of the substrate  50  that faces the first lens  18 . The hydrophobic dielectric film  54  is formed along the inner surfaces of the trenches  52 . One electrode  56  is positioned on each wall in a pair of walls  52 A of each trench  52 , and the electrodes  56  are covered by the hydrophobic dielectric film  54 . The oil film  58  is formed in contact with the hydrophobic dielectric film  54  and is housed within the trenches  52 . The liquid  60  covers the oil film  58  and is separated therefrom. In the present embodiment, the liquid  60  is sealed inside the space between the hydrophobic dielectric film  54  and the first lens  18 . The liquid  60  is water, for example. 
         [0085]    As shown in  FIG. 9 , in the present embodiment, the emission direction control device  22  is replaced by an emission direction control device  22 B. The emission direction control device  22 B includes the electrodes  56  and a driver circuit  62 . The driver circuit  62  applies voltages to the electrodes  56  and also changes the voltages applied to the electrodes  56 . The interfaces between the oil film  54  and the liquid  60  are modified by applying different voltages to the right- and left-side electrodes  56  in each trench  52 . In other words, in the present embodiment the interfaces between the oil film  54  and the liquid  60  are controlled using electro-wetting. Controlling the interfaces between the oil film  54  and the liquid  60  makes it possible to make the interfaces between the oil film  58  and the liquid  60  that overlap with one of the pixels  16  when the display panel  12  is viewed from the front side function as lens surfaces similar to those in Embodiment 1 (that is, similar to the first lens  18 -side lens surfaces (light-exiting surfaces) of the second lenses  20 ). As a result, the direction of light emitted from the pixels  16  can be changed as that light exits the oil film  58 . Therefore, like in Embodiment 1, the apparent number of pixels in the horizontal direction can be increased by a factor of two. 
         [0086]    Embodiments of the present invention were described in detail above. However, these are only examples, and the present invention is not limited in any way by the embodiments described above. 
         [0087]    For example, the pixels in Embodiments 1 and 2 may further include sub-pixels that emit yellow light, or the pixels may be monochrome pixels.