PATENT DOCUMENT

Abstract:
A light emitting device includes a first layer that generates light by injection current and forms a waveguide for the light, and an electrode that injects the current into the first layer, wherein the waveguide has a first region, a second region, and a third region, the first region and the second region connect at a first reflection part, the first region and the third region connect at a second reflection part, the second region and the third region extend to an output surface, a longitudinal direction of the first region is parallel to the output surface, and a first light output from the second region at the output surface and a second light output from the third region at the output surface are output in parallel to one another.

Full Description:
BACKGROUND 
     1. Technical Field 
     The present invention relates to a light emitting device and a projector. 
     2. Related Art 
     A super luminescent diode (hereinafter, also referred to as “SLD”) is a semiconductor light emitting device that can output several hundreds of milliwatts similar to a semiconductor laser, while exhibiting a broadband spectrum and thus being incoherent similar to a typical light emitting diode. 
     An SLD is sometimes used as a light source of a projector. To realize a light source having high power and small etendue, it is desirable that light beams output from plural gain regions travel in the same direction. In JP-A-2010-3833, by combining a gain region having a linear shape and a gain region having a flexed shape via a reflection surface, light beams output from light output parts (light emitting areas) of the two gain regions travel in the same direction. 
     To reduce loss of an optical system and reduce the number of optical components, a projector that can perform light collimation and uniform illumination simultaneously by providing a light emitting device immediately below a light valve and using a lens array, has been proposed. In this type of projector, however, it is necessary to provide light output parts according to intervals of the lens array. 
     In the technology described in JP-A-2010-3833, it is difficult to arrange plural light output parts at distances according to various lens arrays with different intervals, and the technology is not applicable to the projector of the above described type. 
     SUMMARY 
     An advantage of some aspects of the invention is to provide a light emitting device that may be applied to a projector in which distances between plural light output parts may be made larger and a light emitting device is provided immediately below a light valve. Another advantage of some aspects of the invention is to provide a projector having the light emitting device. 
     A light emitting device according to an aspect of the invention includes a first layer that generates light by injection current and forms a waveguide for the light, a second layer and a third layer that sandwich the first layer and suppress leakage of the light, and an electrode that injects the current into the first layer, wherein the waveguide has a first region having a belt-like (elongated) linear shape, a belt-like second region, and a belt-like third region, the first region and the second region connect at a first reflection part provided at a first side surface of the first layer, the first region and the third region connect at a second reflection part provided at a second side surface of the first layer different from the side surface on which the first reflection part is provided, the second region and the third region connect at a third side surface of the first layer which is an output surface that is different from the first and second side surfaces, a longitudinal direction of the first region is parallel to the output surface, and a first light output from the second region at the output surface and a second light output from the third region at the output surface are output in parallel. 
     According to the light emitting device, for example, as compared to the case where the first region is not parallel to the output surface, distances between the light output parts may be made larger without increasing the total length of the first region, the second region, and the third region. That is, the distances between the light output parts may be made larger while the device lengths in the direction perpendicular to the light output surfaces are downsized. As such, a great amount of current is not necessary and electrical power consumption may be suppressed. Further, resources are not wasted and the manufacturing cost may be suppressed. 
     In the light emitting device according to the aspect of the invention, the output surface may have a reflectance lower than a reflectance of the first reflection part and the second reflection part in a wavelength range of the light generated in the first layer. 
     According to the light emitting device, the distances between the plural light output parts may be made larger. 
     In the light emitting device according to the aspect of the invention, the first region and the second region may be tilted at a first angle with respect to a perpendicular of the first side surface as seen from a stacking direction of the first layer, and the second layer, the first region and the third region may be tilted at a second angle with respect to a perpendicular of the second side surface as seen from the stacking direction of the first layer, and the second layer, and the first angle and the second angle are equal to or more than a critical angle. 
     According to the light emitting device, the first reflection part and the second reflection part may totally reflect the light generated in the first region, the second region, and the third region. Therefore, light loss in the first reflection part and the second reflection part may be suppressed and light may efficiently be reflected. 
     In the light emitting device according to the aspect of the invention, the second region and the third region may extend to the output surface in the same direction as seen from a stacking direction of the first layer, and the second layer. 
     According to the light emitting device, the distances between the plural light output parts may be made larger. 
     In the light emitting device according to the aspect of the invention, the second region and the third region may be tilted with respect to a perpendicular of the output surface and extend to the output surface as seen from the stacking direction of the first layer, and the second layer. 
     According to the light emitting device, it may be possible to prevent multiple reflections of the light generated in the first region, the second region, and the third region. As a result, it may be possible to prevent the formation of a direct resonator, and laser oscillation of the light generated in the first region, the second region, and the third region may be suppressed. 
     In the light emitting device according to the aspect of the invention, the second region and the third region may be parallel to a perpendicular of the output surface and extend to the output surface as seen from the stacking direction of the first layer, and the second layer. 
     According to the light emitting device, the design of a downstream optical system may be made easier. 
     In the light emitting device according to the aspect of the invention, the second region may have a linear first part and a linear second part, the third region may have a linear third part and a linear fourth part, the first part and the second part may connected at a third reflection part provided on a fourth side surface of the first layer that is different from the first side surface, the second side surface, and the output surface, and the third part and the fourth part may connected at a fourth reflection part provided on a fifth side surface of the first layer that is different from the first side surface, the second side surface, the fourth side surface, and the output surface. 
     According to the light emitting device, the light generated in the first region, the second region, and the third region may be easier to totally reflect in the first reflection part, the second reflection part, the third reflection part, and the fourth reflection part. 
     In the light emitting device according to the aspect of the invention, the output surface may have a reflectance lower than a reflectance of the third reflection part and the fourth reflection part in a wavelength range of the light generated in the first layer. 
     According to the light emitting device, the distances between the light output parts may be made larger. 
     In the light emitting device according to the aspect of the invention, the first part and the second part may be tilted at a third angle with respect to a perpendicular of the fourth side surface, as seen from the stacking direction of the first layer, and the second layer, the third part and the fourth part may be tilted at a fourth angle with respect to a perpendicular of the fifth side surface as seen from the stacking direction of the first layer, and the second layer, and the third angle and the fourth angle may be equal to or more than a critical angle. 
     According to the light emitting device, the third reflection part and the fourth reflection part may totally reflect the light generated in the first region, the second region, and the third region. Therefore, light loss in the third reflection part and the fourth reflection part may be suppressed and light may efficiently be reflected. 
     In the light emitting device according to the aspect of the invention, a length of the first region may be larger than a length of the second region and a length of the third region. 
     According to the light emitting device, the distances between the light output parts may reliably be made larger. 
     A light emitting device according to another aspect of the invention includes a multilayered structure having a first layer, and second and third layers that sandwich the first layer; the first layer has a first gain region, a second gain region, and a third gain region that generate and guide light; the second layer and the third layer are layers that suppress leakage of the light generated in the first gain region, the second gain region, and the third gain region; the first layer has a first surface, a second surface, and a third surface forming an outer perimeter shape of the multilayered structure; a reflectance of the first surface is lower than a reflectance of the second surface and a reflectance of the third surface in a wavelength range of the light generated in the first gain region, the second gain region and the third gain region; the first gain region is provided parallel to the first surface and extends from the second surface to the third surface as seen from a stacking direction of the multilayered structure, the second gain region overlaps the first gain region at the second surface and extends from the second surface to the first surface, the third gain region overlaps the first gain region at the third surface and extends from the third surface to the first surface, and the second gain region and the third gain region are separated from each other and tilted at the same angle and extend to the first surface as seen from the stacking direction of the multilayered structure. 
     According to the light emitting device, the distances between the light output parts may be made larger while downsizing is realized. 
     A projector according to still another aspect of the invention includes the light emitting device according to the aspect of the invention, a microlens that collimates light output from the light emitting device, a light modulation device that modulates the light collimated by the microlens in response to image information, and a projection device that projects an image formed by the light modulation device. 
     According to the projector, alignment of the lens array may be simplified and the light modulation device may be irradiated with good uniformity. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements. 
         FIG. 1  is a plan view schematically showing a light emitting device according to an embodiment of the invention. 
         FIG. 2  is a sectional view schematically showing the light emitting device according to the embodiment. 
         FIG. 3  is a sectional view schematically showing a manufacturing process of the light emitting device according to the embodiment. 
         FIG. 4  is a plan view schematically showing a manufacturing process of the light emitting device according to the embodiment. 
         FIG. 5  is a sectional view schematically showing a manufacturing process of the light emitting device according to the embodiment. 
         FIG. 6  is a plan view schematically showing a light emitting device according to a first modified example of the embodiment. 
         FIG. 7  is a sectional view schematically showing a light emitting device according to a second modified example of the embodiment. 
         FIG. 8  is a plan view schematically showing a light emitting device according to a third modified example of the embodiment. 
         FIG. 9  schematically shows a projector according to the embodiment. 
         FIG. 10  schematically shows the projector according to the embodiment. 
         FIG. 11  schematically shows a light source of the projector according to the embodiment. 
         FIG. 12  is a sectional view schematically showing the light source of the projector according to the embodiment. 
         FIG. 13  is a sectional view schematically showing the light source of the projector according to the embodiment. 
         FIG. 14  is a sectional view schematically showing the light source of the projector according to the embodiment. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Below, a preferred embodiment of the invention will be explained with reference to the drawings. 
     1. Light Emitting Device 
     First, a light emitting device according to the embodiment will be explained with reference to the drawings.  FIG. 1  is a plan view schematically showing a light emitting device  100  according to the embodiment.  FIG. 2  is a sectional view along II-II line of  FIG. 1  schematically showing the light emitting device  100  according to the embodiment. Note that, in  FIG. 1 , for convenience, an illustration of a second electrode  114  is omitted. 
     Below, the case where the light emitting device  100  is an SLD of an InGaAlP system (red) will be explained. Unlike a semiconductor laser, the SLD can prevent laser oscillation by suppressing the formation of a resonator due to edge reflection. Accordingly, speckle noise may be reduced. 
     As shown in  FIGS. 1 and 2 , the light emitting device  100  may include a multilayered structure  120 , a first electrode  112 , and the second electrode  114 . 
     The multilayered structure  120  may have a substrate  102 , a second layer  104  (also referred to as “first cladding layer  104 ”), a first layer  106  (also referred to as “active layer  106 ”), a third layer  108  (also referred to as “second cladding layer  108 ”), a fourth layer  110  (also referred to as “contact layer  110 ”), and an insulating layer  116 . 
     As the substrate  102 , for example, a first conductivity-type (for example, n-type) GaAs substrate or the like may be used. 
     The first cladding layer  104  is formed on the substrate  102 . As the first cladding layer  104 , for example, an n-type InGaAlp layer or the like may be used. Note that, although not illustrated, a buffer layer may be formed between the substrate  102  and the first cladding layer  104 . As the buffer layer, for example, an n-type GaAs layer, AlGaAs layer, InGaP layer, or the like may be used. The buffer layer may improve the crystal quality of layers formed thereon. 
     The active layer  106  is formed on the first cladding layer  104 . The active layer  106  is sandwiched between the first cladding layer  104  and the second cladding layer  108 . The active layer  106  has a multiple quantum well (MQW) structure in which three quantum well structures each including an InGaP well layer and an InGaAlP barrier layer, for example, are stacked. 
     The planar shape of the active layer  106  is the same as the planar shape of the multilayered structure  120 , for example. In the example shown in  FIG. 1 , the planar shape of the active layer  106  is a hexagonal shape and has a first surface  131 , a second surface  132 , a third surface  133 , a fourth surface  134 , a fifth surface  135 , and a sixth surface  136 . The surfaces  131  to  136  are the surfaces of the active layer  106 , do not have in plane contact with the first cladding layer  104  and the second cladding layer  108 , and form an outer shape of the multilayered structure  120 . The surfaces  131  to  136  are flat surfaces provided on the side surfaces (side walls) of the active layer  106  as seen from the stacking direction of the multilayered structure  120 , in other words, in side surface parts of the multilayered structure  120 . 
     In the example shown in  FIG. 1 , the surfaces  134 ,  135  are orthogonal to the surface  131 . The surface  136  is opposed to the surface  131 . The surface  132  is connected to the surfaces  134 ,  136  and tilted with respect to the surface  131 . The surface  133  is connected to the surfaces  135 ,  136  and tilted with respect to the surface  131 . For example, the surfaces  131 ,  134 ,  135 ,  136  are formed by cleavage and the surfaces  132 ,  133  are formed by etching. 
     Parts of the active layer  106  form a first gain region  150 , a second gain region  160 , and a third gain region  170 . The gain regions  150 ,  160 ,  170  may generate light and the light may be amplified while propagating through the gain regions  150 ,  160 ,  170 . That is, the gain regions  150 ,  160 ,  170  also serve as waveguides for the light generated in the active layer  106 . 
     The first gain region  150  has a belt-like linear longitudinal shape having a predetermined width (a shape having a longitudinal direction and a shorter direction) in a plan view from the stacking direction of the multilayered structure  120  as shown in  FIG. 1 . Further, as seen from the stacking direction of the multilayered structure  120  (in the plan view), the first gain region  150  is provided so that its longitudinal direction from the second surface  132  toward the third surface  133  may be parallel to the first surface  131 . The first gain region  150  has a first end surface  181  provided on the second surface  132  and a second end surface  182  provided on the third surface  133 . Note that the longitudinal direction of the first gain region  150  is an extension direction of a straight line passing through the center of the first end surface  181  and the center of the second end surface  182  in the plan view from the stacking direction of the multilayered structure  120 , for example. Further, the longitudinal direction may be an extension direction of a boundary line of the first gain region  150  (and the part except the first gain region  150 ). 
     Note that “the first gain region  150  is parallel to the first surface  131 ” means that the tilt angle of the first gain region  150  with respect to the first surface  131  is within ±1° in the plan view in consideration of manufacturing variations. 
     The first gain region  150  is connected to the second surface  132  tilted at a first angle α 1  with respect to a perpendicular line P 2  of the second surface  132  in the plan view from the stacking direction of the multilayered structure  120 . In other words, the longitudinal direction of the belt-like shape of the first gain region  150  has the angle α 1  with respect to the perpendicular line P 2 . Further, the first gain region  150  is connected to the third surface  133  tilted at a second angle α 2  with respect to a perpendicular line P 3  of the third surface  133 . In other words, the longitudinal direction of the belt-like shape of the first gain region  150  has the angle α 2  with respect to the perpendicular line P 3 . 
     The length of the first gain region  150  is larger than the length of the second gain region  160  and the length of the third gain region  170 . The length of the first gain region  150  may be equal to or more than the sum of the lengths of the second gain region  160  and the third gain region  170 . Note that “the length of the first gain region  150 ” is also a distance between the center of the first end surface  181  and the center of the second end surface  182 . Regarding the other gain regions, similarly, the length is also a distance between the centers of two end surfaces. 
     The second gain region  160  has, for example, a belt-like linear longitudinal shape having a predetermined width from the second surface  132  to the first surface  131  in the plan view from the stacking direction of the multilayered structure  120 . The second gain region  160  has a third end surface  183  provided on to the second surface  132  and a fourth end surface  184  provided on the first surface  131 . Note that “the longitudinal direction of the second gain region  160 ” is an extension direction of a straight line passing through the center of the third end surface  183  and the center of the fourth end surface  184  in the plan view from the stacking direction of the multilayered structure  120 , for example. Further, the longitudinal direction may be an extension direction of a boundary line of the second gain region  160  (and the part except the second gain region  160 ). The third end surface  183  of the second gain region  160  overlaps with the first end surface  181  of the first gain region  150  on the second surface  132 . In the illustrated example, the first end surface  181  and the third end surface  183  completely overlap. 
     The second gain region  160  is connected to the second surface  132  tilted at the first angle α 1  with respect to the perpendicular line P 2  in the plan view from the stacking direction of the multilayered structure  120 . In other words, the longitudinal direction of the second gain region  160  has the angle α 1  with respect to the perpendicular line P 2 . That is, the angle of the first gain region  150  with respect to the perpendicular line P 2  and the angle of the second gain region  160  with respect to the perpendicular line P 2  are the same in the range of manufacturing variations. The first angle α 1  is an acute angle and equal to or more than the critical angle. As such, the second surface  132  may totally reflect the light generated in the gain regions  150 ,  160 ,  170 . Note that “the angle of the first gain region  150  with respect to the perpendicular line P 2  and the angle of the second gain region  160  with respect to the perpendicular line P 2  are the same” means that they have an angle difference within about ±2°, for example, in consideration of manufacturing variations of etching or the like. 
     The second gain region  160  is connected to the first surface  131  tilted at an angle β with respect to a perpendicular line P 1  of the first surface  131  in the plan view from the stacking direction of the multilayered structure  120 . In other words, the longitudinal direction of the second gain region  160  has the angle β with respect to the perpendicular line P 1 . The angle β is an acute angle less than the critical angle. Note that the second gain region  160  may be parallel to the perpendicular line P 1  of the first surface  131  (β=0°). 
     The third gain region  170  has, for example, a belt-like linear longitudinal shape having a predetermined width from the third surface  133  to the first surface  131  in the plan view from the stacking direction of the multilayered structure  120 . That is, the third gain region  170  has a fifth end surface  185  provided on to the third surface  133  and a sixth end surface  186  provided on the first surface  131 . Note that “the longitudinal direction of the third gain region  170 ” is an extension direction of a straight line passing through the center of the fifth end surface  185  and the center of the sixth end surface  186  in the plan view from the stacking direction of the multilayered structure  120 , for example. Further, the longitudinal direction may be an extension direction of a boundary line of the third gain region  170  (and the part except the third gain region  170 ). The fifth end surface  185  of the third gain region  170  overlaps with the second end surface  182  of the first gain region  150  on the third surface  133 . In the illustrated example, the second end surface  182  and the fifth end surface  185  completely overlap. 
     The second gain region  160  and the third gain region  170  are separated from each other. In the example shown in  FIG. 1 , the fourth end surface  184  of the second gain region  160  and the sixth end surface  186  of the third gain region  170  are separated at a distance D. 
     The third gain region  170  is connected to the third surface  133  tilted at the second angle α 2  with respect to the perpendicular line P 3  in the plan view from the stacking direction of the multilayered structure  120 . In other words, the longitudinal direction of the third gain region  170  has the angle α 2  with respect to the perpendicular line P 3 . That is, the angle of the first gain region  150  with respect to the perpendicular line P 3  and the angle of the third gain region  170  with respect to the perpendicular line P 3  are the same in the range of manufacturing variations. The second angle α 2  is an acute angle and equal to or more than the critical angle. As such, the third surface  133  may totally reflect the light generated in the gain regions  150 ,  160 ,  170 . Note that “the angle of the first gain region  150  with respect to the perpendicular line P 3  and the angle of the third gain region  170  with respect to the perpendicular line P 3  are the same” means that they have an angle difference within about ±2°, for example, in consideration of manufacturing variations of etching or the like. 
     The third gain region  170  is connected to the first surface  131  tilted at the angle β with respect to the perpendicular line P 1  in the plan view from the stacking direction of the multilayered structure  120 . In other words, the longitudinal direction of the third gain region  170  has the angle β with respect to the perpendicular line P 1 . That is, the second gain region  160  and the third gain region  170  are connected to the first surface  131  and tilted at the same angle so as to be parallel to each other in the plan view. More specifically, the longitudinal direction of the second gain region  160  and the longitudinal direction of the third gain region  170  are parallel to each other. As such, a light  20  output from the fourth end surface  184  and a light  22  output from the sixth end surface  186  may travel in the same direction. The end surfaces  184 ,  186  may serve as light output parts (light emitting areas). Note that the third gain region  170  may be parallel to the perpendicular line P 1  of the first surface  131  (β=0°). 
     As described above, by setting the angles α 1 , α 2  equal to or more than the critical angle and the angle β less than the critical angle, reflectance of the first surface  131  may be made lower than reflectance of the second surface  132  and reflectance of the third surface  133 . That is, the first surface  131  may serve as a light output surface and the fourth end surface  184  and the sixth end surface  186  provided on the output surface may serve as light output parts (light emitting areas) that output light generated in the gain regions  150 ,  160 ,  170 . The second surface  132  and the third surface  133  may serve as reflection surfaces and the first end surface  181  and the third end surface  183  provided on the reflection surface may serve as a first reflection part (a first reflection area) that reflects the light generated in the gain regions  150 ,  160 ,  170 . Similarly, the second end surface  182  and the fifth end surface  185  provided on the reflection surface may serve as a second reflection part (a second reflection area) that reflects the light generated in the gain regions  150 ,  160 ,  170 . 
     Note that, although not illustrated, for example, the first surface  131  may be covered by an antireflection film and the second surface  132  and the third surface  133  may be covered by reflection films. As such, even when incident angles, refractive indices, and the like may not satisfy the total reflection condition, the reflectance of the first surface  131  in the wavelength band of the light generated in the gain regions  150 ,  160 ,  170  may be made lower than that of the second surface  132  and the third surface  133 . Further, since the first surface  131  is covered by the antireflection film, direct multiple reflections of the light generated in the gain regions  150 ,  160 ,  170  between the fourth end surface  184  and the sixth end surface  186  may considerably be reduced. As a result, it may be possible to prevent formation of a direct resonator, and laser oscillation of the light generated in the gain regions  150 ,  160 ,  170  may be suppressed. As the reflection film and the antireflection film, SiO 2  layers, Ta 2 O 5  layers, Al 2 O 3  layers, TiN layers, TiO 2  layers, SiON layers, SiN layers, multilayer films of them, or the like may be used. Further, higher reflectance may be obtained using DBR (Distributed Bragg Reflector) formed by etching the part of the multilayered structure  120  outside the surfaces  132 ,  133 . 
     Furthermore, the angle β may be set to an angle larger than 0°. As such, it may be possible to prevent direct multiple reflections of the light generated in the gain regions  150 ,  160 ,  170  between the fourth end surface  184  and the sixth end surface  186 . As a result, it may be possible to prevent formation of a direct resonator, and laser oscillation of the light generated in the gain regions  150 ,  160 ,  170  may be suppressed or prevented. 
     The second cladding layer  108  is formed on the active layer  106  as shown in  FIG. 2 . As the second cladding layer  108 , for example, a second conductivity-type (for example, p-type) InGaAlP layer or the like may be used. 
     For example, the p-type second cladding layer  108 , the active layer  106  not doped with impurity, and the n-type first cladding layer  104  form a pin diode. Each of the first cladding layer  104  and the second cladding layer  108  is a layer having a larger forbidden band gap and a lower refractive index than those of the active layer  106 . The active layer  106  has a function of generating light and amplifying and guiding the light. The first cladding layer  104  and the second cladding layer  108  sandwich the active layer  106  and have a function of confining injected carriers (electrons and holes) and light (suppressing leakage of light). 
     In the light emitting device  100 , when a forward bias voltage of the pin diode is applied between the first electrode  112  and the second electrode  114  (when a current is injected), the gain regions  150 ,  160 ,  170  are produced in the active layer  106  and recombination of electrons and holes occurs in the gain regions  150 ,  160 ,  170 . Light is generated by the recombination. Starting from the generated light, stimulated emission occurs and the intensity of the light is amplified within the gain regions  150 ,  160 ,  170 . 
     For example, as shown in  FIG. 1 , the light generated in the second gain region  160  and traveling toward the second surface  132  side is amplified within the second gain region  160 , and then reflected by the second surface  132  (end surfaces  181 ,  183 ) and travels in the first gain region  150  toward the third surface  133 . Then, the light is further reflected by the third surface  133  (end surfaces  182 ,  185 ), travels in the third gain region  170 , and is output from the sixth end surface  186  as the output light  22 . Concurrently, the intensity of the light is also amplified within the gain regions  150 ,  170 . Similarly, the light generated in the third gain region  170  and traveling toward the third end surface  133  side is amplified within the third gain region  170 , and then reflected by the third surface  133  and travels in the first gain region  150  toward the second surface  132 . Then, the light is further reflected by the second surface  132 , travels in the second gain region  160 , and is output from the fourth end surface  184  as the output light  20 . Concurrently, the intensity of the light is also amplified within the gain regions  150 ,  160 . 
     Note that the light generated in the second gain region  160  includes light directly output from the fourth end surface  184  as the output light  20 . Similarly, the light generated in the third gain region  170  includes light directly output from the sixth end surface  186  as the output light  22 . This light is similarly amplified in the respective gain regions  160 ,  170 . 
     The contact layer  110  is formed on the second cladding layer  108  as shown in  FIG. 2 . The contact layer  110  may have ohmic contact with the second electrode  114 . The upper surface  113  of the contact layer  110  may be a contact surface between the contact layer  110  and the second electrode  114 . As the contact layer  110 , for example, a p-type GaAs layer may be used. 
     The contact layer  110  and part of the second cladding layer  108  may compose a columnar part  111 . The planar shape of the columnar part  111  is the same as the planar shapes of the gain regions  150 ,  160 ,  170  as seen from the stacking direction of the multilayered structure  120 . That is, the planar shape of the upper surface  113  of the contact layer  110  may be the same as the planar shapes of the gain regions  150 ,  160 ,  170 . For example, current channels between the electrodes  112 ,  114  are determined by the planar shape of the columnar part  111  and, as a result, the planar shapes of the gain regions  150 ,  160 ,  170  are determined. Note that, although not illustrated, the side surface of the columnar part  111  may be inclined. 
     The insulating layer  116  may be formed at sides of the columnar part  111  on the second cladding layer  108 . The insulating layer  116  may be in contact with the side surfaces of the columnar part  111 . The upper surface of the insulating layer  116  may be continuous with the upper surface  113  of the contact layer  110 , for example. As the insulating layer  116 , for example, a SiN layer, an SiO 2  layer, an SiON layer, an Al 2 O 3  layer, a polyimide layer, or the like may be used. 
     When the above described material is used for the insulating layer  116 , the current between the electrodes  112 ,  114  may flow in the columnar part  111  sandwiched between the insulating layers  116 . The insulating layer  116  may have a smaller refractive index than the refractive index of the second cladding layer  108 . In this case, the effective refractive index of the vertical section of the part in which the insulating layer  116  is formed is smaller than the effective refractive index of the vertical section of the part in which the insulating layer  116  is not formed, i.e., the part in which the columnar part  111  is formed. As such, in the planar direction, the light may efficiently be confined within the gain regions  150 ,  160 ,  170 . Note that, although not illustrated, the insulating layer  116  may not be provided. In this case, an air surrounding the columnar part  111  may function as the insulating layer  116 . 
     The first electrode  112  is formed on the entire lower surface of the substrate  102 . The first electrode  112  may be in contact with a layer that has ohmic contact with the first electrode  112  (the substrate  102  in the illustrated example). The first electrode  112  is electrically connected to the first cladding layer  104  via the substrate  102 . The first electrode  112  is one electrode for driving the light emitting device  100 . As the first electrode  112 , for example, an electrode formed by stacking a Cr layer, an AuGe layer, a Ni layer, and an Au layer in this order from the substrate  102  side may be used. 
     Note that a second contact layer (not shown) may be provided between the first cladding layer  104  and the substrate  102 , the second contact layer may be exposed by dry etching or the like from the opposite side to the substrate  102 , and the first electrode  112  may be provided on the second contact layer. As such, a single-sided electrode structure may be obtained. This configuration is especially advantageous when the substrate  102  is insulative. 
     The second electrode  114  is formed in contact with the upper surface  113  of the contact layer  110 . Further, the second electrode  114  may be formed on the insulating layer  116  as shown in  FIG. 2 . The second electrode  114  is electrically connected to the second cladding layer  108  via the contact layer  110 . The second electrode  114  is the other electrode for driving the light emitting device  100 . As the second electrode  114 , for example, an electrode formed by stacking a Cr layer, an AuZn layer, and an Au layer in this order from the contact layer  110  side may be used. 
     So far, the case of the InGaAlP system has been explained as an example of the light emitting device  100  according to the embodiment, and any material system that can form a gain region may be used for the light emitting device  100 . For example, a semiconductor material of an AlGaN system, a GaN system, an InGaN system, a GaAs system, an AlGaAs system, an InGaAs system, an InP system, an InGaAsP system, a GaInNAs system, a ZnCdSe system, or the like may be used. 
     The light emitting device  100  according to the embodiment may be applied to a light source of a projector, a display, an illumination device, a measurement device, or the like, for example. 
     The light emitting device  100  according to the embodiment has the following characteristics, for example. 
     According to the light emitting device  100 , the first gain region  150  is provided from the second surface  132  to the third surface  133  parallel to the first surface  131  on which the light output parts  184 ,  186  are formed. Accordingly, for example, as compared to the case where the first gain region is not parallel to the first surface, distances between the light output parts may be made larger without increasing the total length of the gain region. That is, the distances between the plural light output parts may be made larger while the device length in the direction perpendicular to the light output surface is made smaller. As such, in the light emitting device  100 , a great amount of current is not necessary and electrical power consumption may be suppressed. Further, resources are not wasted and the manufacturing cost may be suppressed. More specifically, in the light emitting device  100 , the distance D between the light output parts  184 ,  186  may be set equal to or more than 0.262 mm and less than 3 mm, the angle β may be set equal to or less than 5° (including 0°), and the entire lengths of the gain regions  150 ,  160 ,  170  may be set equal to or more than 1.5 mm and equal to or less than 3 mm. 
     For example, when the entire length of the gain region becomes larger, generally, higher power may be realized, however, a great amount of current is necessary to obtain the so-called population inversion and, as a result, higher efficiency may not be realized unless the device is used unnecessarily higher light output. That is, with light output less than the predetermined light output, the efficiency is deteriorated. Further, when the entire length of the gain region becomes larger, the area of the entire device becomes larger, and problems of wasted resources, rising manufacturing costs, and the like arise. In the light emitting device  100  according to the embodiment, these problems may be avoided. 
     According to the light emitting device  100 , the first gain region  150  and the second gain region  160  are connected to the second surface  132  and may be tilted at the first angle α 1  with respect to the perpendicular line P 2  of the second surface  132 , and the first gain region  150  and the third gain region  170  are connected to the third surface  133  and may be tilted at the second angle α 2  with respect to the perpendicular line P 3  of the third surface  133 . The angles α 1 , α 2  may be equal to or more than the critical angle. Accordingly, the surfaces  132 ,  133  may totally reflect the light generated in the gain regions  150 ,  160 ,  170 . Therefore, in the light emitting device  100 , light loss on the surfaces  132 ,  133  (the end surfaces  181 ,  183  and the end surfaces  182 ,  185 ) may be suppressed and the light may efficiently be reflected. Further, the process of forming the reflection films on the surfaces  132 ,  133  is not necessary, and the manufacturing cost and the materials and resources used for manufacturing the films may be reduced. 
     According to the light emitting device  100 , the length of the first gain region  150  may be made larger than the length of the second gain region  160  and the length of the third gain region  170 . As such, the distance D between the light output parts  184 ,  186  may reliably be made larger. 
     2. Manufacturing Method of Light Emitting Device 
     Next, a manufacturing method of the light emitting device according to the embodiment will be explained with reference to the drawings.  FIG. 3  is a sectional view schematically showing a manufacturing process of the light emitting device  100  according to the embodiment corresponding to  FIG. 2 .  FIG. 4  is a plan view schematically showing a manufacturing process of the light emitting device  100  according to the embodiment corresponding to  FIG. 1 .  FIG. 5  is a sectional view schematically showing a manufacturing process of the light emitting device  100  according to the embodiment corresponding to  FIG. 2 . 
     As shown in  FIG. 3 , on the substrate  102 , the first cladding layer  104 , the active layer  106 , the second cladding layer  108 , and the contact layer  110  are epitaxially grown in this order. As the growth method, for example, an MOCVD (Metal Organic Chemical Vapor Deposition) method, an MBE (Molecular Beam Epitaxy) method, or the like may be used. 
     As shown in  FIG. 4 , the contact layer  110 , the second cladding layer  108 , the active layer  106 , the first cladding layer  104 , and the substrate  102  are patterned, and the second surface  132  and the third surface  133  are formed. The patterning is performed using photolithography and etching, for example. Note that, although not illustrated, as long as the second surface  132  and the third surface  133  of the active layer  106  are exposed, parts of the cladding layer  104  and the substrate  102  are not necessarily patterned. Further, the surfaces  134 ,  135 ,  136  may be formed at the same time with the surfaces  132 ,  133  using photolithography and etching, but they may also be formed by cleavage or the like after fabrication of the columnar part  111  and the electrodes  112 ,  114 , which will be described later. 
     As shown in  FIG. 5 , the contact layer  110  and the second cladding layer  108  are patterned. Through the process, the columnar part  111  may be formed. 
     As shown in  FIG. 2 , the insulating layer  116  is formed to cover the side surfaces of the columnar part  111 . Specifically, first, an insulating member (not shown) is deposited on the second cladding layer  108  (including the contact layer  110 ) by a CVD (Chemical Vapor Deposition) method, a coating method, or the like, for example. Then, the upper surface  113  of the contact layer  110  is exposed using etching or the like, for example. Through the above described processes, the insulating layer  116  may be formed. 
     Then, the second electrode  114  is formed on the contact layer  110  and on the insulating layer  116 . Then, the first electrode  112  is formed on the lower surface of the substrate  102 . The first electrode  112  and the second electrode  114  are formed by vacuum evaporation, for example. Note that the order of formation of the first electrode  112  and the second electrode  114  is not particularly limited. 
     Through the above described processes, the light emitting device  100  according to the embodiment may be manufactured. 
     According to the manufacturing method of the light emitting device  100 , the light emitting device  100  in which the distances of the light output parts may be made larger while downsizing is realized may be obtained. 
     3. Modified Examples of Light Emitting Device 
     Next, light emitting devices according to modified examples of the embodiment will be explained with reference to the drawings. Below, in the light emitting devices according to modified examples of the embodiment, the same signs are assigned to the members having the same functions as those of the light emitting device  100  according to the embodiment, and a detailed explanation will be omitted. 
     3.1. Light Emitting Device According to the First Modified Example 
     First, a light emitting device according to the first modified example of the embodiment will be explained with reference to the drawings.  FIG. 6  is a plan view schematically showing a light emitting device  200  according to the first modified example of the embodiment. Note that, in  FIG. 6 , for convenience, illustration of the second electrode  114  is omitted. 
     In the example of the light emitting device  100 , as shown in  FIG. 1 , the second gain region  160  has been the belt-like linear longitudinal shape provided from the second surface  132  to the first surface  131 . Similarly, the third gain region  170  has been the belt-like linear longitudinal shape provided from the third surface  133  to the first surface  131 . On the other hand, in the light emitting device  200 , as shown in  FIG. 6 , the second gain region  160  is provided from the second surface  132  to the first surface  131  via the fourth surface  134 , and the third gain region  170  is provided from the third surface  133  to the first surface  131  via the fifth surface  135 . In the light emitting device  200 , the fourth surface  134  and the fifth surface  135  are tilted with respect to the first surface  131  in the plan view from the stacking direction of the multilayered structure  120 . The surfaces  134 ,  135  are formed by etching, for example. 
     More specifically, the second gain region  160  includes a first gain part  162  having a belt-like linear longitudinal shape with a predetermined width from the second surface  132  to the fourth surface  134  and a second gain part  164  having a belt-like linear longitudinal shape with a predetermined width from the fourth surface  134  to the first surface  131 . 
     The first gain part  162  has a third end part  183  provided on the second surface  132  and a seventh end surface  187  provided on the fourth surface  134 . The second gain part  164  has an eighth end surface  188  provided on the fourth surface  134  and a fourth end surface  184  provided on the first surface  131 . The seventh end surface  187  and the eighth end surface  188  completely overlap on the fourth surface  134 , for example. In other words, the first gain part  162  and the second gain part  164  are connected on the fourth surface  134  (the end surfaces  187 ,  188 ). The fourth surface  134  (the end surfaces  187 ,  188 ) functions as a reflection surface (third reflection part:third reflection area). Note that “the longitudinal direction of the first gain part  162 ” is an extension direction of a straight line passing through the center of the third end surface  183  and the center of the seventh end surface  187  in the plan view from stacking direction of the multilayered structure  120 , for example. Further, the longitudinal direction may be an extension direction of a boundary line of the first gain part  162  (and the part except the first gain part  162 ). Similarly, the longitudinal direction of the second gain part  164  is an extension direction of a straight line passing through the center of the fourth end surface  184  and the center of the eighth end surface  188  in the plan view from the stacking direction of the multilayered structure  120 , for example. Further, the longitudinal direction may be an extension direction of a boundary line of the second gain part  164  (and the part except the second gain part  164 ). 
     Each of the first gain part  162  and the second gain part  164  is connected to the fourth surface  134  and tilted at an a third angle α 3  with respect to a perpendicular line P 4  of the fourth surface  134  in the plan view from the stacking direction of the multilayered structure  120 . In other words, each of the longitudinal direction of the first gain part  162  and the longitudinal direction of the second gain part  164  has the angle α 3  with respect to the perpendicular line P 4 . The third angle α 3  is an acute angle and equal to or more than the critical angle. As such, the fourth surface  134  may totally reflect the light generated in the gain regions  150 ,  160 ,  170 . 
     The third gain region  170  includes a third gain part  172  having a belt-like linear longitudinal shape with a predetermined width from the third surface  133  to the fifth surface  135  and a fourth gain part  174  having a belt-like linear longitudinal shape with a predetermined width from the fifth surface  135  to the first surface  131 . 
     The third gain part  172  has a fifth end part  185  provided on the third surface  133  and a ninth end surface  189  provided on the fifth surface  135 . The fourth gain part  174  has a tenth end surface  190  provided on the fifth surface  135  and a sixth end surface  186  provided in the connection part to the first surface  131 . The ninth end surface  189  and the tenth end surface  190  completely overlap on the fifth surface  135 , for example. In other words, the third gain part  172  and the fourth gain part  174  are connected on the fifth surface  135  (the end surfaces  189 ,  190 ). The fifth surface  135  (the end surfaces  189 ,  190 ) functions as a reflection surface (fourth reflection part:fourth reflection area). Note that the longitudinal direction of the third gain part  172  is an extension direction of a straight line passing through the center of the fifth end surface  185  and the center of the ninth end surface  189  in the plan view of from the stacking direction the multilayered structure  120 , for example. Further, the longitudinal direction may be an extension direction of a boundary line of the third gain part  172  (and the part except the third gain part  172 ). Similarly, “the longitudinal direction of the fourth gain part  174 ” is an extension direction of a straight line passing through the center of the sixth end surface  186  and the center of the tenth end surface  190  in the plan view of from the stacking direction the multilayered structure  120 , for example. Further, the longitudinal direction may be an extension direction of a boundary line of the fourth gain part  174  (and the part except the fourth gain part  174 ). 
     Each of the third gain part  172  and the fourth gain part  174  is connected to the fifth surface  135  and tilted at an a fourth angle α 4  with respect to a perpendicular line P 5  of the fifth surface  135  in the plan view from the stacking direction of the multilayered structure  120 . In other words, each of the longitudinal direction of the third gain part  172  and the longitudinal direction of the fourth gain part  174  has the angle α 4  with respect to the perpendicular line P 4 . The fourth angle α 4  is an acute angle and equal to or more than the critical angle. As such, the fifth surface  135  may totally reflect the light generated in the gain regions  150 ,  160 ,  170 . 
     Each of the second gain part  164  and the fourth gain part  174  is tilted at the angle β with respect to the perpendicular line P 1  of the first surface  131  so as to be parallel to each other in the plan view from the stacking direction of the multilayered structure  120 . In other words, each of the longitudinal direction of the second gain part  164  and the longitudinal direction of the fourth gain part  174  has the angle β with respect to the perpendicular line P 1 . Note that the angle β may be 0°. 
     According to the light emitting device  200 , as compared to the example of the light emitting device  100 , the first angle α 1  and the second angle α 2  may be set larger. Accordingly, in the light emitting device  200 , the light generated in the gain regions  150 ,  160 ,  170  may be easier to be totally reflected on the second surface  132  and the third surface  133 . 
     3.2. Light Emitting Device According to the Second Modified Example 
     Next, a light emitting device according to the second modified example of the embodiment will be explained with reference to the drawings.  FIG. 7  is a sectional view schematically showing a light emitting device  300  according to the second modified example of the embodiment corresponding to  FIG. 2 . 
     In the example of the light emitting device  100 , as shown in  FIG. 2 , the waveguide of the index-guiding type in which light is confined by the refractive index difference provided between the region where the insulating layer  116  is formed and the region where the insulating layer  116  is not formed, i.e., the region where the columnar part  111  is formed and the light is confined has been explained. On the other hand, in the light emitting device  300 , a waveguide of the gain-guiding type in which the columnar part  111  is not formed, i.e., the refractive index difference is not provided and the gain regions  150 ,  160 ,  170  serve as waveguide regions as they are may be employed as shown in  FIG. 7 . 
     That is, in the light emitting device  300 , the contact layer  110  and the second cladding layer  108  do not compose the columnar part  111 , and the insulating layer  116  is not formed at the sides thereof. The insulating layer  116  may be formed on the contact layer  110  except the parts of the gain regions  150 ,  160 ,  170 . That is, the insulating layer  116  may have openings at the gain regions  150 ,  160 ,  170  and the upper surface  113  of the contact layer  110  may be exposed in the openings. The second electrode  114  may be formed on the exposed parts of the contact layer  110  and the insulating layer  116 . 
     The upper surface  113  of the contact layer  110  being contact with the second electrode  114  has the same planar shape as those of the gain regions  150 ,  160 ,  170 . In the illustrated example, current channels between the electrodes  112 ,  114  are determined by the planar shape of the contact surface between the second electrode  114  and the contact layer  110  and, as a result, the planar shapes of the gain regions  150 ,  160 ,  170  are determined. Note that, although not illustrated, the second electrode  114  may not be formed on the insulating layer  116 , and instead may be formed only on the contact layer  110  at the gain regions  150 ,  160 ,  170 . 
     According to the light emitting device  300 , as in the light emitting device  100 , the distances between the light output parts may be made larger while downsizing is realized. 
     3.3. Light Emitting Device According to the Third Modified Example 
     Next, a light emitting device according to the third modified example of the embodiment will be explained with reference to the drawings.  FIG. 8  is a plan view schematically showing a light emitting device  400  according to the third modified example of the embodiment. Note that, in  FIG. 8 , for convenience, an illustration of the second electrode  114  is omitted. 
     In the example of the light emitting device  100 , as shown in  FIG. 1 , one first gain region  150 , one second gain region  160 , and one third gain region  170  have been provided. On the other hand, in the light emitting device  400 , as shown in  FIG. 8 , plural first gain regions  150 , plural second gain regions  160 , and plural third gain regions  170  are respectively provided. 
     That is, the first gain region  150 , the second gain region  160 , and the third gain region  170  may form a group of gain regions  450 , and, in the light emitting device  400 , plural groups of gain regions  450  are provided. In the illustrated example, three groups of gain regions  450  are provided, however, the number of groups is not particularly limited. 
     The plural groups of gain regions  450  are arranged in a direction orthogonal to the direction in which the perpendicular line P 1  of the first surface  131  extends. More specifically, they are arranged so that, in the adjacent groups of gain regions  450 , the distance between the sixth end surface  186  of one group of gain regions  450  and the fourth end surface  184  of the other group of gain regions  450  may be D (the distance between the light output parts). As such, the light  20 ,  22  may easily enter a lens array, which will be described later. 
     According to the light emitting device  400 , higher power may be realized as compared to the example of the light emitting device  100 . 
     4. Projector 
     Next, a projector according to the embodiment will be explained with reference to the drawings.  FIG. 9  schematically shows a projector  700  according to the embodiment.  FIG. 10  schematically shows part of the projector  700  according to the embodiment. Note that, in  FIG. 9 , for convenience, a casing forming the projector  700  is omitted, and further, a light source  600  is simplified for illustration. Further, in  FIG. 10 , for convenience, the light source  600 , a lens array  702 , and a liquid crystal light valve  704  are illustrated, and further, the light source  600  is simplified for illustration. 
     The projector  700  includes a red light source  600 R, a green light source  600 G, and a blue light source  600 B that output red light, green light, and blue light as shown in  FIG. 9 . The light sources  600 R,  600 G,  600 B have the light emitting devices according to the invention. In the following example, the light sources  600 R,  600 G,  600 B having the light emitting devices  400  as the light emitting devices according to the invention will be explained. 
       FIG. 11  schematically shows the light source  600  of the projector  700  according to the embodiment.  FIG. 12  is a sectional view along XII-XII of  FIG. 1  schematically showing the light source  600  of the projector  700  according to the embodiment. 
     The light source  600  may have the light emitting devices  400 , a base  610 , and sub-mounts  620  as shown in  FIGS. 11 and 12 . 
     The two light emitting devices  400  and the sub-mount  620  may form a structure  630 . Plural structures  630  are provided and arranged in the direction (Y-axis direction) orthogonal to the arrangement direction (X-axis direction) of the end surfaces  184 ,  186  which are the light output parts of the light emitting devices  400  as shown in  FIG. 11 . The structures  630  may be arranged so that the distance between the light output parts in the X-axis direction and the distance between the light output parts in the Y-axis direction may be equal. As such, the light output from the light emitting devices  400  may easily enter the lens array  702 . 
     The two light emitting devices  400  forming the structure  630  are provided with the sub-mount  620  sandwiched in between. In the example shown in  FIGS. 11 and 12 , the two light emitting devices  400  are provided so that the second electrodes  114  may be opposed via the sub-mount  620 . On part of the surface of the sub-mount  620  being contact with the second electrode  114 , for example, wiring is formed. As such, voltages may individually be supplied to the respective plural second electrodes  114 . As the material of the sub-mount  620 , for example, aluminum nitride and aluminum oxide may be cited. 
     The base  610  supports the structures  630 . In the example shown in  FIG. 12 , the base  610  is connected to the first electrodes  112  of the plural light emitting devices  400 . As such, the base  610  may function as a common electrode of the plural first electrodes  112 . As the material of the base  610 , for example, copper and aluminum may be cited. Although not illustrated, the base  610  may be connected to a heat sink via a Peltier device. 
     Note that the form of the structure  630  is not limited to the example shown in  FIGS. 11 and 12 . For example, as shown in  FIG. 13 , two light emitting devices  400  forming the structure  630  may be provided so that the first electrode  112  of one light emitting device  400  and the second electrode  114  of the other light emitting device  400  may be opposed via the sub-mount  620 . Alternatively, as shown in  FIG. 14 , they may be provided so that the first electrodes  112  of the two light emitting devices  400  may be a common electrode. 
     As shown in  FIG. 9 , the projector  700  further includes lens arrays  702 R,  702 G,  702 B and transmissive liquid crystal light valves (light modulation devices)  704 R,  704 G,  704 B, and a projection lens (projection device)  708 . 
     The light output from the respective light sources  600 R,  600 G,  600 B enter the respective lens arrays  702 R,  702 G,  702 B. As shown in  FIG. 10 , the lens array  702  may have flat surfaces  701  that the light  20 ,  22  output from the light output parts  184 ,  186  enters. Plural flat surfaces  701  are provided in correspondence with the plural light output parts  184 ,  186  and arranged at equal distances. Further, the normal lines of the flat surfaces  701  are tilted with respect to the optical axes of the light  20 ,  22 . By the flat surfaces  701 , the optical axes of the light  20 ,  22  may be made orthogonal to an irradiated surface  705  of the liquid crystal light valve  704 . Especially, when the angles β formed by the first surface  131  and the second and the third gain regions  160 ,  170  are not 0°, the light  20 ,  22  output from the respective light output parts  184 ,  186  are tilted with respect to the perpendicular line P 1  of the first surface  131 , and thus, it is desirable that the flat surfaces  701  are provided. 
     The lens array  702  may have convex curved surfaces  703  at the liquid crystal light valve  704  side. Plural convex curved surfaces  703  are provided in correspondence with the plural flat surfaces  701  and arranged at equal distances. The light  20 ,  22  with optical axes converted on the flat surfaces  701  are collected (collimated) or traveling at diffusion angles reduced by the convex curved surfaces  703 , and may be superimposed (partially superimposed). As such, the liquid crystal light valve  704  may be irradiated with good uniformity. 
     As described above, the lens array  702  may control the optical axes of the light  20 ,  22  output from the light source  600  and integrate the light  20 ,  22 . 
     As shown in  FIG. 9 , the light integrated by the respective lens arrays  702 R,  702 G,  702 B enters the respective liquid crystal light valves  704 R,  704 G,  704 B. The respective liquid crystal light valves  704 R,  704 G,  704 B respectively modulate the incident light in response to image information. Then, the projection lens  708  enlarges images formed by the liquid crystal light valves  704 R,  704 G,  704 B and projects them on a screen (display surface)  710 . 
     Further, the projector  700  may include a cross dichroic prism (color combining unit)  706  that combines light output from the liquid crystal light valves  704 R,  704 G,  704 B and guides the light to the projection lens  708 . 
     The three colors of light modulated by the respective liquid crystal light valves  704 R,  704 G,  704 B enter the cross dichroic prism  706 . The prism is formed by bonding four right angle prisms, and a dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light are provided crosswise on its inner surfaces. By the dielectric multilayer films, the three colors of light are combined and light representing a color image is formed. Then, the combined light is projected on the screen  710  by the projection lens  708  as a projection system, and the enlarged image is displayed thereon. 
     According to the projector  700 , the light emitting devices  400  that may make distances between the plural light output parts larger while downsizing is realized is provided. Accordingly, in the projector  700 , alignment of the lens array  702  may be easy and the liquid crystal light valve  704  may be irradiated with good uniformity. 
     Note that, in the above described example, transmissive liquid crystal light valves have been used as the light modulation devices, however, other light valves than liquid crystal, or reflective light valves may be used. As the light valves, for example, reflective liquid crystal light valves and digital micromirror devices may be used. Further, the configuration of the projection system may appropriately be changed depending on the type of the light valves employed. 
     Further, the light source  600  and the lens array  702  may be modularized in alignment with each other. Furthermore, the light source  600 , the lens array  702 , and the light valve  704  may be modularized in alignment with one another. 
     In addition, the light source  600  may also be applied to a light source device of a scanning type image display device (projector) having a means of scanning light for displaying an image in a desired size on a display surface. 
     The above described embodiments and modified examples are just examples, and the invention is not limited to these. For example, the respective embodiments and the respective modified examples may be appropriately combined. 
     The embodiments of the invention have been specifically explained above, and a person skilled in the art could easily understand that many modifications may be carried out without substantively departing from the spirit and effect of the invention. Therefore, these modified examples are included in the range of the invention. 
     The entire disclosure of Japanese Patent Application No. 2011-051570 filed Mar. 9, 2011 is expressly incorporated by reference herein.