Abstract:
Disclosed is a light source device which is made compact while suppressing increase in non-uniformity of brightness caused by existence of a non-light emitting portion between a plurality of light sources. A light source device is characterized in that a plurality of light diffusers have a first light diffuser located in front of a first light source in the light exit direction closely thereto, and a second light diffuser located in front of a second light source in the light exit direction closely thereto. The first light diffuser includes a first light absorbing material which absorbs visible light emitted from the first light source more easily than visible light emitted from the second light source, and the second light diffuser includes a second light absorbing material which absorbs visible light emitted from the second light source more easily than visible light emitted from the first light source.

Description:
TECHNICAL FIELD   
       [0001]    The present invention relates to a light source device and a display unit equipped with the light source device. 
       BACKGROUND ART  
       [0002]    An exemplary light source device is a backlight device of a liquid crystal display unit. Such a light source device emits light from a main surface of a light guide plate on which light from a light source is incident. The light source may be a cold cathode fluorescent lamp (CCFL) which is a linear light source and a light emitting device (LED) which is a point light source. 
         [0003]    With the above light source device, however, when, for example, plural linear light sources are arranged to provide a large-sized light source device or plural point light sources are arranged to provide even a small-sized light source device, a degree of non-uniformity in brightness tends to increase in a vicinity of a light incident portion of the light guide plate in which light from the plural light sources is introduced because of the existence of non-light emitting portions between the light sources. Under these circumstances, techniques of controlling an increase in the degree of non-uniformity in brightness have been developed and disclosed in, for example, PTLs 1 and 2. 
       CITATION LIST  
     Patent Literatures 
       [0004]    PTL 1: Japanese Unexamined Patent Application Publication No. 9-259623 
         [0005]    PTL 2: Japanese Unexamined Patent Application Publication No. 2001-110224 
       SUMMARY OF INVENTION  
     Technical Problem 
       [0006]    In an LED light source back light module disclosed in PTL 1, since it is necessary to provide an area in which a recessed portion for introduction of light and a reflective surface on a side of the light guide plate on which the light sources are mounted, that area cannot be used as a display area. Similarly, in a surface emitting device disclosed in PTL 2, since it is necessary to provide an area for the formation of shaped parts or other parts integrated with the light guide plate, the area cannot be used as a display area. Accordingly, it is difficult to provide a compact light source device with the techniques disclosed in PTLs 1 and 2 because of the large dead space. 
         [0007]    The present invention has been devised in view of the foregoing circumstances and an object thereof is to provide a compact light source device with a reduced degree of non-uniformity in brightness in light emitted by plural light sources, and a display unit equipped with the light source device. 
       Solution to Problem 
       [0008]    A light source device according to the present invention includes; plural light sources disposed in a line and spaced apart from each other; a light guide which includes a first main surface, a second main surface and a surface disposed to face the light sources, the light guide causing light from the light sources to emit through the first main surface; and plural light diffusers disposed on the second main surface of the light guide, the plural light diffusers diffusing light incident on the light guide. The plural light sources include a first light source group consisting of plural first light sources and a second light source group consisting of plural second light sources. Each of the plural second light sources is disposed between adjacent first light sources of the first light source group and emits light different from light emitted by the first light sources. The plural light diffusers include first light diffusers and second light diffusers. The first light diffusers are located near the first light sources and in front of the first light sources in a light emitting direction. The second light diffusers are located near the second light sources and in front of the second light sources in a light emitting direction. The first light diffusers include a first light absorbing material which absorbs visible light emitted by the first light sources more easily than visible light emitted by the second light sources. The second light diffusers include a second light absorbing material which absorbs visible light emitted by the second light sources more easily than visible light emitted by the first light sources. 
       Advantageous Effects of Invention 
       [0009]    According to the present invention, a compact light source device with a reduced degree of non-uniformity in brightness can be provided. 
         [0010]    According to the present invention, a compact display unit with improved display quality can be provided. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0011]      FIG. 1(   a ) is a plan view and  FIG. 1(   b ) is a sectional view taken along line Ib-Ib in  FIG. 1(   a ), each schematically illustrating a light source device according to a first embodiment of the present invention. 
           [0012]      FIG. 2  is a graph illustrating an exemplary relationship between a light distribution angle of a light source and brightness. 
           [0013]      FIG. 3(   a ) is a plan view and  FIG. 3(   b ) is an enlarged plan view of a main part, each schematically illustrating plural light sources and a light guide illustrated in  FIGS. 1(   a ) and  1 ( b ). 
           [0014]      FIG. 4(   a ) is a plan view and  FIG. 4(   b ) is a sectional view taken along line IIb-IIb in  FIG. 4(   a ), each schematically illustrating a light source device according to a second embodiment of the present invention. 
           [0015]      FIG. 5(   a ) is a plan view and  FIG. 5(   b ) is an enlarged plan view of a main part, each schematically illustrating plural light sources and a light guide illustrated in  FIGS. 4(   a ) and  4 ( b ). 
           [0016]      FIG. 6(   a ) is a plan view and  FIG. 6(   b ) is a sectional view taken along line IIIb-IIIb in  FIG. 6(   a ), each schematically illustrating a light source device according to a third embodiment of the present invention. 
           [0017]      FIG. 7(   a ) is a plan view and  FIG. 7(   b ) is an enlarged plan view of a main part, each schematically illustrating plural light sources and a light guide illustrated in  FIGS. 6(   a ) and  6 ( b ). 
           [0018]      FIG. 8(   a ) is a plan view and  FIG. 8(   b ) is a sectional view taken along line IVb-IVb in  FIG. 8(   a ), each schematically illustrating a light source device according to a fourth embodiment of the present invention. 
           [0019]      FIG. 9(   a ) is a plan view and  FIG. 9(   b ) is an enlarged plan view of a main part, each schematically illustrating plural light sources and a light guide illustrated in  FIGS. 8(   a ) and  8 ( b ). 
           [0020]      FIG. 10(   a ) is a plan view and  FIG. 10(   b ) is a sectional view taken along line Vb-Vb in  FIG. 10(   a ), each schematically illustrating a light source device according to a fifth embodiment of the present invention. 
           [0021]      FIG. 11(   a ) is a plan view and  FIG. 11(   b ) is an enlarged plan view of a main part, each schematically illustrating plural light sources and a light guide illustrated in  FIGS. 10(   a ) and  10 ( b ). 
           [0022]      FIG. 12(   a ) is a plan view and  FIG. 12(   b ) is a sectional view taken along line VIb-VIb in  FIG. 12(   a ), each schematically illustrating a light source device according to a sixth embodiment of the present invention. 
           [0023]      FIG. 13(   a ) is a plan view and  FIG. 13(   b ) is an enlarged plan view of a main part, each schematically illustrating plural light sources and a light guide illustrated in  FIGS. 12(   a ) and  12 ( b ). 
           [0024]      FIG. 14  is a sectional view which schematically illustrates a display unit equipped with the light source device illustrated in  FIG. 1 . 
           [0025]      FIG. 15  is a perspective view which schematically illustrates a display panel in the display unit illustrated in  FIG. 14 . 
       
    
    
     DESCRIPTION OF EMBODIMENTS  
       [0026]      FIGS. 1(   a ) and  1 ( b ) schematically illustrate a light source device X 1  according to a first embodiment of the present invention. 
         [0027]    The light source device X 1  includes plural light sources  10 , a light guide  20 , plural light diffusers  30 , a reflector  40 , a diffuser plate  50  and a prism  60 . 
         [0028]    The light sources  10 , which emit light toward the light guide  20 , are arranged in a line and spaced apart from each other as illustrated in  FIG. 1 . The light sources  10  may be LEDs, cathode fluorescent lamps (CFL), halogen lamps, xenon lamps and electro-luminescence (EL) light sources. Among these, LEDs are preferably selected to provide low power consumption and low noise products. 
         [0029]    The plural light sources  10  include a first light source group  10 A consisting of plural first light sources  10   a  and a second light source group  10 B consisting of plural second light sources  10   b . The second light sources  10   b  emit light different from that emitted by the first light sources  10   a . The first light sources  10   a  are arranged in a line and spaced apart from each other and each of the plural second light sources  10   b  is disposed between adjacent first light sources  10   a.    
         [0030]    In the light source device X 1 , angles at which brightness of the light emitted by the light sources  10   a  of the first light source group  10 A is at or higher than a reference value are defined as first high-intensity distribution angles, and angles at which the brightness is at or lower than the reference value are defined as first low-intensity distribution angles. In the light source device X 1 , angles at which brightness of the light emitted by the light sources  10   b  of the second light source group  10 B is at or higher than a reference value are defined as second high-intensity distribution angles, and angles at which the brightness is at or lower than the reference value are defined as second low-intensity distribution angles. The reference value may be selected desirably depending on required performance and, preferably, may be determined such that a degree of uniformity in brightness on a light emission surface  20   a  which emits light toward a target to be irradiated might be increased. For example, if the brightness of light incident from the light sources  10  in a direction perpendicular to a light incident surface  20   b  of the light guide  20  on which the light from the light source  10  is incident is defined as 1 (i.e., standardized), the reference value is preferably selected to be not smaller than 0.4 but not larger than 0.6.  FIG. 2  is a graph illustrating an exemplary relationship between a light distribution angle of a light source and brightness. According to this graph, if the reference value (i.e., a standard value) is 0.5, angles in a range of −60 degrees to 60 degrees are the high-intensity distribution angles and angles in a range of −90 degrees to −60 degrees and 60 degrees to 90 degrees are low-intensity distribution angles. 
         [0031]    The light guide  20  guides the light emitted by the plural light sources  10  to a target to be irradiated. The light guide  20  is formed in, for example, a rectangular parallelepiped shape including the light emission surface  20   a  as a first main surface, a lower surface  20   c  as a second main surface and the light incident surface  20   b  as a surface facing the light sources. The light emission surface  20   a  is an area through which light is emitted toward a target to be irradiated, such as a display panel. The lower surface  20   c  is disposed opposite to the light incident surface  20   c . The light incident surface  20   b  is an area on which the light from the plural light sources  10  is incident. The light incident surface  20   b  is disposed to face the plural light sources  10 . The light guide  20  may be formed of a translucent material, such as acrylic resin and polycarbonate resin. The “translucent material” herein has transmittance to visible light. 
         [0032]    In the light source device X 1 , the light guide  20  includes first high-intensity distribution areas, first low-intensity distribution areas, second high-intensity distribution areas and second low-intensity distribution areas. The first high-intensity distribution areas are defined as areas on which the light emitted by the first light sources  10   a  of the first light source group  10 A at the first high-intensity distribution angles is incident. The first low-intensity distribution areas are defined as areas other than the first high-intensity distribution areas and are areas on which the light emitted at the first low-intensity distribution angles is incident. In the light guide  20 , the second high-intensity distribution areas are defined as areas on which the light emitted by the second light sources  10   b  of the second light source group  10 B at the second high-intensity distribution angles is incident. The second low-intensity distribution areas are defined as areas other than the second high-intensity distribution areas and are areas on which the light emitted at the second low-intensity distribution angles is incident. 
         [0033]    The light guide  20  includes first sections  21 , second sections  22 , third sections  23  and fourth sections  24 . In  FIGS. 3(   a ) and  3 ( b ), boundaries of the sections  21 ,  22 ,  23  and  24  are indicated by dashed lines. The first sections  21  are located in the first high-intensity distribution areas and also in the second low-intensity distribution areas, and the first light sources  10   a  are disposed to face the first sections  21 . The second sections  22  are located in the first low-intensity distribution areas and also in the second high-intensity distribution areas, and the second light sources  10   b  are disposed to face the second sections  22 . The third sections  23  are located in the first low-intensity distribution areas and also in the second low-intensity distribution areas, and no light sources  10  are disposed to face the third sections  23 . The fourth sections  24  are located in the first high-intensity distribution areas and also in the second high-intensity distribution areas, and at a side of the light sources  10   a  and  10   b  from a base line BL which connects intersections of the boundary lines of the first high-intensity distribution areas and the first low-intensity distribution areas. 
         [0034]      FIGS. 3(   a ) and  3 ( b ) are plan views which illustrate the plural light sources  10 , the light guide  20  and the plural light diffusers  30 . 
         [0035]    The plural light diffusers  30  diffuse light incident thereon via the light guide  20 , and are located on the lower surface  20   c  of the light guide  20 . The plural light diffusers  30  include plural first light diffusers  30   a , plural second light diffusers  30   b , plural third light diffusers  30   c  and plural fourth light diffusers  30   d.    
         [0036]    The plural first light diffusers  30   a  are located in areas corresponding to the first sections  21  and include a first light absorbing material. The first light absorbing material has a function to absorb at least a part of visible light from the light sources  10 . The first light absorbing material absorbs the visible light of the first light sources  10   a  more easily than that of the second light sources  10   b . The first light absorbing material includes, for example, a pigment of a color similar to a complementary color of the light emitted by the first light sources  10   a.    
         [0037]    The plural second light diffusers  30   b  are located in areas corresponding to the second sections  22  and include a second light absorbing material. The second light absorbing material has a function to absorb at least a part of visible light from the light sources  10 . The second light absorbing material absorbs the visible light of the second light sources  10   b  more easily than that of the first light sources  10   a . The second light absorbing material includes, for example, a pigment of a color similar to a complementary color of the light emitted by the second light sources  10   b . Here, an absorption rate of the visible light is determined in, for example, the following manner: a light absorbing material is irradiated with light from a light source; a light emission spectrum of transmitted light and a light emission spectrum of emitted light are measured and represented by a graph of a relationship between light intensity and a wavelength standardized by the maximum intensity; and the absorption rate is determined from an area difference in a visible light region of each spectrum. 
         [0038]    The third light diffusers  30   c  are located in areas corresponding to the third sections  23  and the fourth light diffusers  30   d  are located in areas corresponding to the fourth sections  24 . The third light diffusers  30   c  and the fourth light diffusers  30   d  have controlled absorption of the visible light emitted by the first light sources  10   a  and the visible light emitted by the second light sources  10   b  and include, for example, a white pigment. In the present embodiment, abundance ratios of the third light diffusers  30   c  and the fourth light diffusers  30   d  are substantially the same as abundance ratios of the first light diffusers  30   a  and the first light diffusers  30   b . Here, the abundance ratios of the light diffusers  30   a ,  30   b ,  30   c  and  30   d  are obtained by dividing the total of plan view areas of the light diffusers  30   a ,  30   b ,  30   c  and  30   d  located in the sections corresponding to the areas  21 ,  22 ,  23  and  24  by the total of plan view areas of the sections  21 ,  22 ,  23  and  24 . The term “substantially the same” means that variations within tolerance or manufacturing errors (for example, not greater than ±2%) are included. 
         [0039]    In the present embodiment, the light diffusers  30  are plural point structures arranged in predetermined patterns. The light diffusers  30  may be formed of materials similar to those of the light guide  20 . The light diffusers  30  are formed by, for example, applying the above-described material by known screen printing, ink jet printing or other method or providing grooves of predetermined shape (i.e., projections and depressions) on the lower surface  20   c  itself of the light guide  20  by molding or other method. 
         [0040]    The reflector  40  reflects light emitted from surfaces other than the light emission surface  20   a  of the light guide  20  to be directed to the light guide  20 . In the present embodiment, the reflector  40  is disposed to face the lower surface  20   c  of the light guide  20 . The reflector  40  also reflects light not incident on the light guide  20  among the light emitted by the plural light sources  10  to be directed to the light guide  20 . A part of the reflector  40  covers a part of the plural light sources  10 . The reflector  40  may be formed of, for example, metals, such as silver, aluminum and alloys thereof, white foam fabricated by stretching a polyethylene terephthalate (PET)-based material, and a sheet consisting of a PET-based material-containing base on which a metal, such as silver, is deposited. 
         [0041]    The diffuser plate  50  increases a degree of uniformity in brightness in the light emitted by the light emission surface  20   a  of the light guide  20  toward a target to be irradiated. The diffuser plate  50  is disposed to face the light emission surface  20   a  of the light guide  20 . The diffuser plate  50  may be formed of, for example, a sheet consisting of a base which includes a resin material, such as PET, on which silica bead-containing resin is cured and a sheet in which silica beads are mixed in a resin material, such as polycarbonate (PC). 
         [0042]    The prism  60  refracts incident light. The light incident on the prism  60  is refracted and emitted in a direction substantially perpendicular to the light emission surface  20   a  of the light guide  20 . The prism  60  may be fabricated by, for example, stacking a prism structure formed of an acrylic material on a base which includes a resin material, such as PET, or forming a prism structure in the base itself which includes a resin material, such as PC. 
         [0043]    In the light source device X 1  according to the present embodiment, the first light diffusers  30   a  corresponding to the first sections  21  include the first light absorbing material, and the second light diffusers  30   b  corresponding to the second sections  22  include the second light absorbing material. That is, in the light source device X 1 , at least a part of the visible light from the first light sources  10   a  is absorbed in the first sections  21  in which brightness tends to increase when the light sources  10   a  emit light because the first sections  21  are located near the light sources  10   a  of the first light source group  10 A among other places in the first high-intensity distribution areas. Similarly, in the light source device X 1 , at least a part of the visible light emitted by the second light sources  10   b  is absorbed in the second sections  22  in which brightness tends to increase when the light sources  10   b  emit light because the second sections  22  are located near the light sources  10   b  of the second light source group  10 B among other places in the second high-intensity distribution areas. Thus, in the light source device X 1 , brightness can be reduced in sections in which brightness tends to increase relatively as in the first sections  21  when the light sources  10   a  of the first light source group  10 A emit light or the second sections  22  when the light sources  10   b  of the second light source group  10 B emit light. Accordingly, in the light source device X 1 , a degree of non-uniformity in brightness resulting from relatively increased brightness in the first sections  21  and the second sections  22  can be reduced. 
         [0044]    In the light source device X 1 , the first sections  21 , the second sections  22  and the third sections  23  can be used as display areas. Thus, creation of unnecessary dead space can be avoided when the light from the plural light sources  10  is incident on the light guide  20  and, therefore, a compact light source device X 1  can be provided. 
         [0045]    In the light source device X 1 , if the first light absorbing material includes a pigment of a color similar to a complementary color of the light emitted by the first light sources  10   a , light can be reduced more efficiently in the first sections  21  by the first light absorbing material. If the second light absorbing material includes a pigment of a color similar to a complementary color of the second light sources  10   b , light can be reduced more efficiently in the second sections  22  by the second light absorbing material. In the light source device X 1 , if the third light diffusers  30   c  corresponding to the third sections  23  include a white pigment, a decrease in brightness in the third sections  23  in which brightness tends to decrease relatively because of their being located in the first low-intensity distribution areas and in the second low-intensity distribution areas can be controlled. Accordingly, in the light source device X 1 , a degree of non-uniformity in brightness resulting from relatively decreased brightness in the third sections  23  can be reduced. 
         [0046]      FIGS. 4(   a ) and  4 ( b ) schematically illustrate a light source device X 2  according to a second embodiment of the present invention.  FIGS. 5(   a ) and  5 ( b ) are plan views illustrating plural light sources  10 , a light guide  20  and plural light diffusers  30 A. 
         [0047]    The light source device X 2  differs from the light source device X 1  in that the light diffusers  30 A are employed in place of the light diffusers  30 . Components of the light source device X 2  that are common to those of the above-described light source device X 1  will not be described. 
         [0048]    The plural light diffusers  30 A differ from the above-described light diffusers  30  in that an abundance ratio of the third light diffusers  30 Ac is set higher than abundance ratios of the first light diffusers  30 Aa and the second light diffusers  30 Ab, and an abundance ratio of the fourth light diffusers  30 Ad is set lower than an abundance ratio of the third light diffusers  30 Ac. 
         [0049]    The light source device X 2  according to the present embodiment provides the same advantageous effects as those provided by the light source device X 1 . In addition, in the light source device X 2  according to the present embodiment, since the abundance ratio of the third light diffusers  30 Ac corresponding to the third sections  23  is higher than the abundance ratio of the first light diffusers  30 Aa corresponding to the first sections  21  and is higher than the abundance ratio of the second light diffusers  30 Ab corresponding to the second sections  22 , brightness in the third sections  23  in which brightness tends to decrease can be further increased. Accordingly, in the light source device X 2 , a degree of non-uniformity in brightness resulting from relatively decreased brightness in the third sections  23  can be further reduced. 
         [0050]    In the light source device X 2 , the abundance ratio of the fourth light diffusers  30 Ad corresponding to the fourth sections  24  is lower than the abundance ratio of the third light diffusers  30 Ac corresponding to the third sections  23 . Accordingly, in the light source device X 2 , a difference between brightness in the fourth sections in which brightness tends to increase because of their being located in the first high-intensity distribution areas and also in the second high-intensity distribution areas and brightness in the third sections  23  can be reduced. Accordingly, in the light source device X 2 , a degree of non-uniformity in brightness resulting from the difference between brightness in the third sections  23  and brightness in the fourth sections  24  can be reduced. 
         [0051]      FIGS. 6(   a ) and  6 ( b ) schematically illustrate a light source device X 3  according to a third embodiment of the present invention.  FIGS. 7(   a ) and  7 ( b ) is a plan view illustrating plural light sources  10 , a light guide  20  and plural light diffusers  30 B. 
         [0052]    The light source device X 3  differs from the light source device X 2  in that the light diffusers  30 B are employed in place of the light diffusers  30 . Components of the light source device X 3  that are common to those of the above-described light source device X 1  will not be described. 
         [0053]    The plural light diffusers  30 B differ from the above-described light diffusers  30  in that second light diffusers  30 Bd includes both a first light absorbing material and a second light absorbing material. 
         [0054]    The light source device X 3  according to the present embodiment provides the same advantageous effects as those provided by the light source device X 1 . In addition, in the light source device X 3  according to the present embodiment, since the fourth light diffusers  30 Bd corresponding to the fourth sections  24  include both the first light absorbing material and the second light absorbing material, a difference between brightness in the fourth sections  24  in which brightness tends to increase because of their being located in the first high-intensity distribution areas and also in the second high-intensity distribution areas and brightness in the sections  21 ,  22  and  23  can be reduced. Accordingly, in the light source device X 3 , a degree of non-uniformity in brightness resulting from the difference between brightness in the sections  21 ,  22  and  23  and brightness in the fourth sections  24  can be reduced. 
         [0055]      FIGS. 8(   a ) and  8 ( b ) schematically illustrate a light source device X 4  according to a fourth embodiment of the present invention.  FIGS. 9(   a ) and  9 ( b ) are plan views illustrating plural light sources  10 , a light guide  20  and plural light diffusers  30 C. 
         [0056]    The light source device X 4  differs from the light source device X 3  in that the light diffusers  30 C are employed in place of the light diffusers  30 B. Components of the light source device X 4  that are common to those of the above-described light source devices X 1  and X 3  will not be described. 
         [0057]    The plural light diffusers  30 C in the present embodiment differ from the above-described light diffusers  30 B in that an abundance ratio of fourth light diffusers  30 Cd is set lower than abundance ratios of first light diffusers  30 Ca and second light diffusers  30 Cb. 
         [0058]    The light source device X 4  according to the present embodiment provides the same advantageous effects as those provided by the light source device X 3 . In addition, in the light source device X 4  according to the present embodiment, the abundance ratio of the fourth light diffusers  30 Cd corresponding to the fourth sections  24  is lower than the abundance ratio of the first light diffusers  30 Ca corresponding to the first sections  21  and is lower than the abundance ratio of the second light diffusers  30 Cb corresponding to the second sections  22 . Thus, even when brightness in the fourth sections  24  tends to be higher than brightness in the sections  21 ,  22  and  23  as in a case in which the light sources  10   a  of the first light source group  10 A and the light sources  10   b  of the second light source group  10 C are made to emit light simultaneously, a difference between brightness in the fourth sections  24  and brightness in the sections  21 ,  22  and  23  can be reduced. Accordingly, in the light source device X 4 , a degree of non-uniformity in brightness resulting from the difference between brightness in the sections  21 ,  22  and  23  and brightness in the fourth sections  24  can be reduced even in a case of simultaneous light emission as described above. 
         [0059]      FIGS. 10(   a ) and  10 ( b ) schematically illustrate a light source device X 5  according to a fifth embodiment of the present invention.  FIGS. 11(   a ) and  11 ( b ) are plan views illustrating plural light sources  10 , a light guide  20  and plural light diffusers  30 D. 
         [0060]    The light source device X 5  differs from the light source device X 1  in that the light diffusers  30 D are employed in place of the light diffusers  30 . Components of the light source device X 5  that are common to those of the above-described light source device X 1  will not be described. 
         [0061]    The plural light diffusers  30 D differ from the light source device X 2  in that an abundance ratio of fourth light diffusers  30 Dd is lower than an abundance ratio of first light diffusers  30 Da and is lower than an abundance ratio of first light diffusers  30 Db. 
         [0062]    The light source device X 5  according to the present embodiment provides the same advantageous effects as those provided by the light source device X 1 . In addition, in the light source device X 5  according to the present embodiment, the abundance ratio of the fourth light diffusers  30 Dd corresponding to the fourth sections  24  is lower than the abundance ratio of the first light diffusers  30 Da corresponding to the first sections  21  and is lower than the abundance ratio of the second light diffusers  30 Db corresponding to the second sections  22 . Thus, in the light source device X 5 , even when brightness in the fourth sections  24  tends to be higher than brightness in the sections  21 ,  22  and  23  as in a case in which the light sources  10   a  of the first light source group  10 A and the light sources  10   b  of the second light source group  10 B are made to emit light simultaneously, a difference between brightness in the fourth sections  24  and brightness in the sections  21 ,  22  and  23  can be reduced. Accordingly, in the light source device X 5 , a degree of non-uniformity in brightness resulting from the difference between brightness in the sections  21 ,  22  and  23  and brightness in the fourth sections  24  can be reduced even in a case of simultaneous light emission as described above. 
         [0063]      FIGS. 12(   a ) and  12 ( b ) schematically illustrate a light source device X 6  according to a sixth embodiment of the present invention.  FIGS. 12(   a ) and  12 ( b ) are plan views illustrating plural light sources  10 , a light guide  20 A and plural light diffusers  30 E. 
         [0064]    The light source device X 6  differs from the light source device X 1  in that the light guide plate  20 A is employed in place of the light guide plate  20  and that the light diffusers  30 E are employed in place of the light diffusers  30 . The light sources  10  according to the present embodiment are constituted only by a first light source group  10 A which includes plural first light sources  10   a . Components of the light source device X 6  that are common to those of the above-described light source device X 1  will not be described. 
         [0065]    In the present embodiment, the light sources  10  are constituted only by the first light source group  10 A which includes the plural first light sources  10   a . In the light source device X 6 , angles at which brightness of light emitted by the first light sources  10   a  is at or higher than a reference value are defined as high-intensity distribution angles, and angles at which the brightness is at or lower than the reference value are defined as low-intensity distribution angles. 
         [0066]    The light guide  20 A includes first sections  21 A, second sections  22 A and third sections  23 A. In  FIGS. 13(   a ) and  13 ( b ), boundaries of the sections  21 A,  22 A and  23 A are indicated by dashed lines. The first sections  21 A are located in high-intensity distribution areas of the first light sources  10   a  and also in low-intensity distribution areas of adjacent first light sources  10   a . The first light sources  10   a  are disposed to face the first sections  21 A. The second sections  22 A are located in the low-intensity distribution areas and no first light sources  10   a  are disposed to face the second sections  22 A. The third sections  23 A are located in the high-intensity distribution areas of the first light sources  10   a  and also in the high-intensity distribution areas of adjacent first light sources  10   a , and at a side of the first light sources  10   a  from a base line BL which connects intersections of the boundary lines of the high-intensity distribution areas and the low-intensity distribution areas. 
         [0067]    The plural light diffusers  30 E include plural first light diffusers  30 Ea, plural second light diffusers  30 Eb and plural third light diffusers  30 Ec. The plural first light diffusers  30 Ea are located in sections corresponding to the first sections  21 A. The plural second light diffusers  30 Eb are located in sections corresponding to the second sections  22 A. The plural third light diffusers  30 Ec are located in sections corresponding to the third sections  23 A. The first light diffusers  30 Ea include a light absorbing material. The light absorbing material has a function to absorb at least a part of visible light from the first light sources  10   a  and includes, for example, a pigment of a color similar to a complementary color of the light emitted by the first light sources  10   a . The second light diffusers  30 Eb include, for example, a white pigment which controls the absorption of the visible light from the first light sources  10   a . In the present embodiment, the third light diffusers  30 Ec include a light absorbing material, and an abundance ratio of the third light diffusers  30 Ec is lower than abundance ratios of the first light diffusers  30 Ea and the second light diffusers  30 Eb. 
         [0068]    In the light source device X 6  according to the present embodiment, the first light diffusers  30 Ea corresponding to the first sections  21 A include the light absorbing material. That is, in the light source device X 1 , at least a part of the visible light from the first light sources  10   a  is absorbed in the first sections  21 A in which brightness tends to increase when the light sources  10   a  emit light because the first sections  21 A are located near the light sources  10   a  among other places in the high-intensity distribution areas. Thus, in the light source device X 6 , brightness can be reduced in sections in which brightness tends to increase as in the first sections  21 A when the light sources  10  emit light. Accordingly, in the light source device X 1 , a degree of non-uniformity in brightness resulting from relatively increased brightness in the first sections  21 A can be reduced. 
         [0069]    In the light source device X 6 , the first sections  21 A and the second sections  22 A can be used as display areas. Thus, creation of unnecessary dead space can be avoided when the light emitted by the light sources  10   a  is incident on the light guide  20 A and, therefore, a compact light source device X 6  can be provided. 
         [0070]    In the light source device X 6 , if the second light diffusers  30 Eb corresponding to the second sections  22 A include a white pigment, a decrease in brightness in the second sections  22 A in which brightness tends to decrease relatively can be controlled. Accordingly, in the light source device X 6 , a degree of non-uniformity in brightness resulting from relatively decreased brightness in the second sections  22 A can be reduced. If the abundance ratio of the second light diffusers  30 Eb corresponding to the second sections  22 A is set higher than the abundance ratio of the first light diffusers  30 Ea corresponding to the first sections  21 A, a degree of non-uniformity in brightness resulting from a difference between brightness in the first sections  21 A and brightness in the second sections  22 A can be reduced. 
         [0071]    In the light source device X 6 , the third light diffusers  30 Ac corresponding to the third sections  23 A include the light absorbing material. Thus, even when brightness in the third sections  23 A tends to be higher than brightness in the sections  21 A and  22 A, a difference between brightness in third sections  23 A and brightness in the sections  21 A and  22 A can be reduced. Accordingly, in the light source device X 6 , a degree of non-uniformity in brightness resulting from the difference between brightness in the first sections  21 A and the second sections  22 A and brightness in the third sections  23 A can be reduced. 
         [0072]    In the light source device X 6 , the abundance ratio of the third light diffusers  30 Ec corresponding to the third sections  23 A is lower than the abundance ratio of the first light diffusers  30 Ea corresponding to the first sections  21 A and is lower than the abundance ratio of the second light diffusers  30 Eb corresponding to the second sections  22 A. Thus, even when brightness in the third sections  23 A tends to be higher than brightness in the sections  21 A and  22 A, a difference between the third sections  23  and brightness in the sections  21 A and  22 A can be reduced. Accordingly, a degree of non-uniformity in brightness resulting from the difference between brightness in the sections  21 A and  22 A and brightness in the third sections  23 A can be reduced. 
         [0073]      FIG. 12  is a sectional view schematically illustrating a display unit Y equipped with the light source device X 1  according to the present invention. The display unit Y includes the light source device X 1 , a display panel  70  and a housing  80 . Although the display unit Y will be described with reference to the light source device X 1 , the light source devices X 2 , X 3 , X 4 , X 5  and X 6  may also be employed similarly. 
         [0074]    The display unit Y includes the light source device X 1  and the display panel  70 . 
         [0075]    The display panel  70  is disposed to face the light emission surface  20   a  of the light guide  20  of the light source device X 1  via the diffuser  50  and the prism  60 . 
         [0076]    The display panel  70  includes a first base  71 , a second base  72  and a sealing member  73 . As illustrated in  FIG. 15 , a display area P consisting of plural pixels for displaying images is formed by a first base  71 , a second base  72  and a liquid crystal layer (not illustrated) which is disposed between the first base  71  and the second base  72  and is sealed with a sealing member  73 . 
         [0077]    The housing  80  accommodates the display panel  70  and the light source device X 1 , and includes an upper housing  81  and a lower housing  82 . The housing  80  may be formed of, for example, resin, such as polycarbonate resin, and metal, such as stainless steel (SUS) or aluminum. 
         [0078]    Since the display unit Y according to the present embodiment is equipped with the light source device X 1 , the same advantageous effects as those of the above-described light source device X 1  can be provided. In particular, a compact display unit Y with improved display quality can be provided. 
         [0079]    Although embodiments of the present invention have been described, the present invention is not limited to the same. 
         [0080]    In the light source devices X 1 , X 2 , X 3 , X 4  and X 5 , the first light diffusers  30 ,  30 Aa,  30 Ba,  30 Ca and  30 Da corresponding to the first sections  21  may further include a first light reflective material. The first light diffusers  30 ,  30 Aa,  30 Ba,  30 Ca and  30 Da may be, for example, plural point structures which include the first light absorbing material and the first light reflective material in predetermined amounts or, alternatively, may be a combination of point structures which only include the first light absorbing material and point structures which only include the first light reflective material. The first light reflective material has a function to reflect a part of the light emitted by the first light sources  10   a  and includes, for example, at least one of a pigment of a color similar to that of the light emitted by the first light sources  10   a  and a white pigment. With this, the difference in brightness in the first sections  21  and brightness in other sections  22 ,  23  and  24  can be reduced more appropriately. Note that it is preferred that the first light diffusers  30 ,  30 Aa,  30 Ba,  30 Ca and  30 Da include a component which reflects light emitted by the first light sources  10   a  in an amount greater than a component which reflects light emitted by the first light sources  10   a.    
         [0081]    In the light source devices X 1 , X 2 , X 3 , X 4  and X 5 , the second light diffusers  30   b ,  30 Ab,  30 Bb,  30 Cb and  30 Db corresponding to the second sections  22  may further include a second light reflective material. The first light diffusers  30   a ,  30 Ab,  30 Bb,  30 Cb and  30 Db may be, for example, plural point structures which include the second light absorbing material and the second light reflective material in predetermined amounts or, alternatively, may be a combination of point structures which only include the second light absorbing material and point structures which only include the second light reflective material. The second light reflective material has a function to reflect the light emitted by the second light sources  10   b  and includes, for example, at least one of a pigment of a color similar to that of the light emitted by the second light sources  10   b  and a white pigment. With this, the difference in brightness in the second sections  22  and brightness in other sections  21 ,  23  and  24  can be reduced more appropriately. Note that it is preferred that the second light diffusers  30 Ab,  30 Bb,  30 Cb,  30 Db and  30 Ea include a component which reflects light emitted by the second light sources  10   b  in an amount greater than a component which reflects light emitted by the second light sources  10   b.    
         [0082]    In the light source devices X 1 , X 2 , X 3 , X 4 , X 5  and X 6 , the point structures are formed in a substantially circular cylindrical shape which is substantially circular in a plan view in order to improve manufacturability of the light diffusers  30 ,  30 A,  30 B,  30 C,  30 D and  30 E. However, shapes of the point structures are not limited thereto. For example, the point structures may be formed in a substantially hemispheric shape which is substantially circular in a plan view, a substantially circular cylindrical shape which is substantially elliptical in a plan view, or a substantially polygonal column shape which is substantially polygonal shape in a plan view, which increases arrangement density. Here, the “polygonal shape” is a shape with (2n+1) or greater number of vertices where n is a natural number. 
         [0083]    Although in the light source devices X 1 , X 2 , X 3 , X 4 , X 5  and X 6 , the plural light sources  10  are constituted by a single light source group  10 A or two light source groups  10 A and  10 B, three or more light source groups may also be employed. 
       REFERENCE SIGNS LIST  
       [0084]    X 1 , X 2 , X 3 , X 4 , X 5 , X 6  light source device 
         [0085]    Y display unit 
         [0086]      10  light source 
         [0087]      10 A first light source 
         [0088]      10 B second light source 
         [0089]      20 ,  20 A light guide 
         [0090]      30 ,  30 A,  30 B,  30 C,  30 D,  30 E light diffusers 
         [0091]      40  reflector 
         [0092]      50  diffuser plate 
         [0093]      60  prism 
         [0094]      70  display panel