Patent Publication Number: US-2015062541-A1

Title: Light emitting device and projector

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 element which achieves incoherence like an ordinary light emitting diode and also achieves a broad-range spectral shape while having a light output characteristic such that an output up to several hundred mW can be provided by a single element, as in a semiconductor laser. Such an SLD is used, for example, as a light source of a projector. 
     For example, JP-A-2010-141241 discloses an SLD in which light emitted from two light emitting sections is reflected in a stacking direction (stacking direction of an active layer and a cladding layer) by an inclined surface provided on a lateral side of a light emitting device. 
     However, in the case where the SLD of JP-A-2010-141241 is used as the light source of a projector, when the gain region (optical waveguide) is elongated in order to increase light output, the distance between lenses corresponding to the two light emitting sections increases. On the other hand, when the distance between the lenses corresponding to the two light emitting sections is decreased, the optical waveguide is shortened, reducing light output. In this way, in the SLD of JP-A-2010-141241, it is difficult to decrease the distance between the lenses without reducing the length of the optical waveguide. 
     SUMMARY 
     An advantage of some aspects of the invention is that a light emitting device is provided in which the distance between lenses can be decreased without reducing the length of the optical waveguide. Another advantage of some aspects of the invention is that a projector including the light emitting device is provided. 
     An aspect of the invention is directed to a light emitting device including: an active layer which is injected with current and generates light; a first cladding layer and a second cladding layer which sandwich the active layer; and a first lens, a second lens, a third lens, and a fourth lens on which the light generated by the active layer becomes incident. The active layer forms a first optical waveguide and a second optical waveguide which guide light. The first optical waveguide has a first bouncing section and a second bouncing section which change a traveling direction of the light guided by the first optical waveguide. The second optical waveguide has a third bouncing section and a fourth bouncing section which change a traveling direction of the light guided by the second optical waveguide. The first lens is provided at a position overlapping with the first bouncing section, as viewed from a stacking direction of the active layer and the first cladding layer. The second lens is provided at a position overlapping with the second bouncing section and the second optical waveguide, as viewed from the stacking direction. The third lens is provided at a position overlapping with the third bouncing section and the first optical waveguide, as viewed from the stacking direction. The fourth lens is provided at a position overlapping with the fourth bouncing section, as viewed from the stacking direction. 
     In such a light emitting device, three lenses can be arranged in an overlapping manner on one optical waveguide in plan view. Specifically, the first optical waveguide overlaps with the first lens, the second lens and the third lens. The second optical waveguide overlaps with the second lens, the third lens and the fourth lens. Therefore, in such a light emitting device, the distance between the first lens, the second lens, the third lens and the fourth lens can be decreased without reducing the length of the first optical waveguide and the second optical waveguide, compared with the case where lenses overlap only with both ends of the optical waveguide. 
     In the light emitting device according to the aspect of the invention, the first bouncing section, the second bouncing section, the third bouncing section and the fourth bouncing section may change the traveling direction of light by diffraction. 
     In such a light emitting device, manufacturing cost can be reduced, for example, compared with the case where the traveling direction of light is changed by using a prism. Moreover, in such a light emitting device, the distance between the first optical waveguide and the second optical waveguide can be decreased, thus achieving miniaturization, compared with the case where the traveling direction of light is changed by using a prism. 
     In the light emitting device according to the aspect of the invention, the first optical waveguide may have a fifth bouncing section provided at a position overlapping with the third lens, as viewed from the stacking direction. 
     In such a light emitting device, the number of light emitting sections (sections that emit light) of a light emitting element including the active layer, the first cladding layer and the second cladding layer can be increased. 
     In the light emitting device according to the aspect of the invention, the second optical waveguide may have a sixth bouncing section provided at a position overlapping with the second lens, as viewed from the stacking direction. 
     In such a light emitting device, the number of light emitting sections of a light emitting element including the active layer, the first cladding layer and the second cladding layer can be increased. 
     In the light emitting device according to the aspect of the invention, the first optical waveguide may have a seventh bouncing section provided at a position overlapping with the fourth lens, as viewed from the stacking direction. 
     In such a light emitting device, the length of the first optical waveguide can be increased. Therefore, in such a light emitting device, light output can be increased. 
     In the light emitting device according to the aspect of the invention, the second optical waveguide may have an eighth bouncing section provided at a position overlapping with the first lens, as viewed from the stacking direction. 
     In such a light emitting device, the length of the second optical waveguide can be increased. Therefore, in such a light emitting device, light output can be increased. 
     In the light emitting device according to the aspect of the invention, the first optical waveguide and the second optical waveguide may be integrally formed. 
     In such a light emitting device, the distance between the first lens, the second lens, the third lens and the fourth lens can be decreased without reducing the length of the first optical waveguide and the second optical waveguide. 
     Another aspect of the invention is directed to a projector including: the light emitting device according to the aspect of the invention; a light modulation device which modulates light emitted from the light emitting device, according to image information; and a projection device which projects an image formed by the light modulation device. 
     Such a projector can include the light emitting device in which the length of the first optical waveguide and the second optical waveguide can be increased and the distance between the first lens, the second lens, the third lens and the fourth lens can be decreased. 
    
    
     
       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 a first embodiment. 
         FIG. 2  is a plan view schematically showing the light emitting device according to the first embodiment. 
         FIG. 3  is a cross-sectional view schematically showing the light emitting device according to the first embodiment. 
         FIG. 4  is a cross-sectional view schematically showing the light emitting device according to the first embodiment. 
         FIG. 5  is a perspective view schematically showing the light emitting device according to the first embodiment. 
         FIG. 6  is a perspective view schematically showing the light emitting device according to the first embodiment. 
         FIG. 7  is a cross-sectional view schematically showing a manufacturing process of the light emitting device according to the first embodiment. 
         FIG. 8  is a cross-sectional view schematically showing the manufacturing process of the light emitting device according to the first embodiment. 
         FIG. 9  is a cross-sectional view schematically showing the manufacturing process of the light emitting device according to the first embodiment. 
         FIG. 10  is a plan view schematically showing a light emitting device according a first modification of the first embodiment. 
         FIG. 11  is a plan view schematically showing a light emitting device according a second modification of the first embodiment. 
         FIG. 12  is a plan view schematically showing a light emitting device according a third modification of the first embodiment. 
         FIG. 13  is a plan view schematically showing a light emitting device according to a second embodiment. 
         FIG. 14  is a plan view schematically showing the light emitting device according to the second embodiment. 
         FIG. 15  is a plan view schematically showing a light emitting device according to a modification of the second embodiment. 
         FIG. 16  schematically shows a projector according to a third embodiment. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings. The following embodiments should not unduly limit the contents of the invention described in the appended claims. Not all the configurations described below are essential components of the invention. 
     1. First Embodiment 
     1.1. Light Emitting Device 
     First, a light emitting device according to a first embodiment will be described with reference to the drawings.  FIGS. 1 and 2  are plan views schematically showing a light emitting device  100  according to the first embodiment.  FIG. 3  is a cross-sectional view taken along III-III in  FIG. 2 , schematically showing the light emitting device  100  according to the first embodiment.  FIG. 4  is a cross-sectional view taken along IV-IV in  FIG. 2 , schematically showing the light emitting device  100  according to the first embodiment.  FIG. 5  is a perspective view schematically showing the light emitting device  100  according to the first embodiment. 
     For convenience, in  FIGS. 1 and 2 , a second electrode  122  is omitted and a part of a lens array  190  is transparently shown.  FIG. 2  is an enlarged view of a part of the light emitting device  100  shown in  FIG. 1 . In  FIGS. 3 and 4 , a wiring substrate  2  and the lens array  190  are omitted from the illustrations. 
     The light emitting device  100  includes a light emitting element  101 , a lens array  190 , and a wiring substrate  2 , as shown in  FIG. 5 . The light emitting element  101  includes a substrate  102 , a first cladding layer  104 , an active layer  106 , a second cladding layer  108 , a contact layer  110 , an insulation layer  114 , a first electrode  120 , and a second electrode  122 , as shown in  FIGS. 3 to 5 . 
     Hereinafter, the case where the light emitting element  101  is an InGaAlP-based (red-colored) SLD will be described. In the SLD, unlike a semiconductor laser, laser oscillation can be prevented by suppressing the formation of a resonator formed by edge reflections. Therefore, speckle noise can be reduced. 
     The substrate  102  is, for example, a GaAs substrate of a first conduction type (for example, n-type). The substrate  102  may be capable of transmitting light generated by the active layer  106  (by optical waveguides  160 ,  162 ). 
     The first cladding layer  104  is formed on the substrate  102 . The first cladding layer  104  is, for example, an n-type InGaAlP layer. Although not shown, a buffer layer may be formed between the substrate  102  and the first cladding layer  104 . The buffer layer is, for example, an n-type GaAs layer, AlGaAs layer, InGaP layer or the like. The buffer layer can improve the crystal quality of the layers formed above the buffer layer. 
     The active layer  106  is formed on the first cladding layer  104 . The active layer  106  has, for example, a multiple quantum well (MQW) structure in which three quantum well structures are superimposed, each including an InGaP well layer and an InGaAlP barrier layer. 
     The active layer  106  has, for example, a rectangular shape as viewed from the stacking direction of the active layer  106  and the first cladding layer  104  (hereinafter also referred to as “as viewed in a plan view”). The active layer  106  has a first lateral surface  105  and a second lateral surface  107 , as shown in  FIGS. 1 and 2 . The lateral surfaces  105 ,  107  are opposite each other (parallel surfaces) and are not in surface contact with the cladding layers  104 ,  108 . The lateral surfaces  105 ,  107  are, for example, cleavage planes formed by cleavage. 
     Apart of the active layer  106  forms a first optical waveguide  160  and a second optical waveguide  162  which guide light. In the active layer  106 , the optical waveguides  160 ,  162  can generate light by injection current. The light guided by the optical waveguides  160 ,  162  can receive gain at the portion where current is injected. 
     The first optical waveguide  160  has, for example, a strip-like and straight longitudinal shape, as viewed in a plan view. In the illustrated example, the first optical waveguide  160  is in the shape of a parallelogram, as viewed in a plan view. The length of the first optical waveguide  160  (size in the longitudinal direction) is, for example, approximately 3 mm. The first optical waveguide  160  has a first waveguide section  170 , a first bouncing section  181 , and a second bouncing section  182 , as shown in  FIGS. 2 and 3 . 
     As viewed in a plan view, the first waveguide section  170  is a portion that does not overlap with a grating section  109 , described later, which is provided on the second cladding layer  108  of the first optical waveguide  160 . The first waveguide section  170  extends from the first bouncing section  181  to the second bouncing section  182 . That is, one end of the first waveguide section  170  is connected to the first bouncing section  181 , while the other end of the first waveguide section  170  is connected to the second bouncing section  182 . It can also be said that the first waveguide section  170  connects the first bouncing section  181  and the second bouncing section  182 . The first waveguide section  170  is provided at a position overlapping with a third lens  193  of the lens array  190 , as viewed in a plan view. The first waveguide section  170  has a strip-like and straight longitudinal shape with a predetermined width and along an extending direction of the first waveguide section  170 , as viewed in a plan view. 
     The “extending direction of the first waveguide section  170 ” is, for example, the extending direction of an imaginary straight line L passing through the center of the one end of the first waveguide section  170  and the center of the other end. Also, the “extending direction of the first waveguide section  170 ” may be the extending direction of the boundary of the first waveguide section  170  (and the area excluding the first waveguide section  170 ). This also applies to a second waveguide section  172  of the second optical waveguide  162 . 
     The first waveguide section  170  is in the shape of a parallelogram, as viewed in a plan view. In the example shown in  FIG. 2 , the bouncing sections  181 ,  182  are also in the shape of a parallelogram, as viewed in a plan view. The first waveguide section  170  is inclined with respect to an imaginary straight line P orthogonal to a first boundary B 1  with the first bouncing section  181 . An inclination angle θ of (the imaginary straight line L of) the first waveguide section  170  with respect to the imaginary straight line P is, for example, 0.5° or greater and 1.5° or smaller, though the angle varies depending on the length of the first waveguide section  170 . Similarly, the first waveguide section  170  is inclined with respect to an imaginary straight line (not shown) orthogonal to a second boundary B 2  with the second bouncing section  182 . Thus, direct multiple reflection between the first bouncing section  181  and the second bouncing section  182 , of the light generated in the first waveguide section  170 , can be suppressed. Therefore, formation of a direct resonator can be avoided and laser oscillation of the light generated in the first optical waveguide  160  can be suppressed. Moreover, since the small inclination angle θ of 1.5° or smaller is applied, distortion of the radiation pattern of the light emitted from the light emitting element  101  can be reduced. 
     The boundaries B 1 , B 2  are the boundaries between the first waveguide section  170  and the bouncing sections  181 ,  182 , as viewed in a plan view. In the example shown in  FIG. 2 , the boundaries B 1 , B 2  are parallel to the lateral surfaces  105 ,  107  of the active layer  106 . 
     The inclination angle θ of the first waveguide section  170  with respect to the imaginary straight line P may be 0°. That is, the first waveguide section  170  may be provided orthogonally to the boundaries B 1 , B 2 . For example, by reducing the number of protrusions  108   a , described later, provided on the second cladding layer  108 , laser oscillation of the light generated in the first optical waveguide  160  can be suppressed even in the case of θ=0°. 
     The first waveguide section  170  generates light with the current that is injected by the electrodes  120 ,  122 . The light generated in the first waveguide section  170  is guided by the first waveguide section  170  while receiving gain. 
     As viewed in a plan view, the bouncing sections  181 ,  182  are portions overlapping with the grating section  109 , described later, provided on the second cladding layer  108  of the first optical waveguide  160 . The first bouncing section  181  is provided at the one end of the first waveguide section  170 , and in the illustrated example, on the side of the first lateral surface  105 . The second bouncing section  182  is provided at the other end of the first waveguide section  170 , and in the illustrated example, on the side of the second lateral surface  107 . 
     The bouncing sections  181 ,  182  function as a diffraction grating by the grating section  109 . The bouncing sections  181 ,  182  changes the traveling direction of the light guided by the first waveguide section  170  and causes the light to become incident on lenses  191 ,  192  of the lens array  190 . That is, the bouncing sections  181 ,  182  change the traveling direction of light by diffraction. Specifically, the bouncing sections  181 ,  182  change the traveling direction of the light (bounce the light) that travels through the first waveguide section  170  in a direction (hereinafter referred to as “planar direction”) orthogonal to the stacking direction of the active layer  106  and the first cladding layer  104 , and cause the light to become incident on the lenses  191 ,  192  of the lens array  190 . The bouncing sections  181 ,  182  are, for example, DBRs (distributed Bragg reflectors). 
     The light bounced by the bouncing sections  181 ,  182  travels in a direction that is not parallel to the stacking direction of the active layer  106  and the first cladding layer  104 , when the inclination angle is not θ=0°. Specifically, when the inclination angle θ is 1° or smaller, the traveling direction of the light bounced by the bouncing sections  181 ,  182  is inclined at angle of 5° or smaller with respect to the stacking direction of the active layer  106  and the first cladding layer  104 . 
     The order of the bouncing sections  181 ,  182  (order of the diffraction grating) n is, for example, an even number, though it is not particularly limited as long as the bouncing section  181 ,  182  can cause the light guided by the first waveguide section  170  to become incident on the lenses  191 ,  192  of the lens array  190 . The diffraction grating of the n-th order generates diffracted light of the m-th order (0≦m≦n, m being an integer). When n is an even number, the bouncing sections  181 ,  182  can cause diffracted light of the m=(n/2)-th order to become incident on the lenses  191 ,  192 . Preferably, n=2 may be employed. As n increases above 2, diffracted light of a higher order is generated by the bouncing sections  181 ,  182 . That is, diffracted light that travels in a greater number of directions is generated and this is not preferable in view of light efficiency. 
     The m-th order of the diffracted light is expressed by the following equation (1), where d represents the period of the grating in the grating section  109 , λ represents the wavelength in the first waveguide section  170  of the light generated in the first waveguide section  170 , α represents the incident angle of the light that becomes incident on the bouncing sections  181 ,  182  from the first waveguide section  170 , and β represents the exit angle of the light exiting the bouncing sections  181 ,  182 . 
         d  sin α+ d  sin β= mλ   (1)
 
     In a diffraction grating of the second order (n=2), that is, when d=λ is applied to the equation (1), a component of the light traveling through the first waveguide section  170  in a direction orthogonal to the stacking direction of the active layer  106  and the first cladding layer  104 ) (α=90°) can become a diffracted light of the first order (m=1), a component of the diffracted light traveling in the stacking direction) (β=0°). 
     The bouncing sections  181 ,  182  are situated between the electrodes  120 ,  122 , as shown in  FIG. 3 , and injected with a current by the electrodes  120 ,  122 . The bouncing sections  181 ,  182  can generate light with the injection current. The light guided by the bouncing sections  181 ,  182  can receive gain. 
     Although not shown, the bouncing sections  181 ,  182  may not overlap with the electrodes  120 ,  122  as viewed in a plan view and may not be injected with a current, as long as the bouncing sections  181 ,  182  can guide light. The light guided by the bouncing sections  181 ,  182  may not receive gain. 
     The second optical waveguide  162  is provided at a position overlapping with the second lens  192  of the lens array  190 , as viewed in a plan view, as shown in  FIG. 2 . The second optical waveguide  162  is spaced apart from the first optical waveguide  160 . The distance between the optical waveguides  160 ,  162  is not particularly limited, as long as the second lens  192  overlaps with the second optical waveguide  162  and the third lens  193  overlaps with the first optical waveguide  160 , as viewed in a plan view. 
     The second optical waveguide  162  is situated at a position shifted toward the second lateral surface  107  from the first optical waveguide  160 , as viewed in a plan view. Moreover, the second optical waveguide  162  is situated at a position shifted along the in-plane direction of the first lateral surface  105  or the second lateral surface  107  from the first optical waveguide  160 , as viewed in a plan view. 
     The second optical waveguide  162  may be provided in parallel with the first optical waveguide  160 , as viewed in a plan view. The second optical waveguide  162  may have the same shape and function as the first optical waveguide  160 . Hereinafter, the portions of the second optical waveguide  162  to which the description of the first optical waveguide  160  can be applied will not be described further in detail. 
     The second optical waveguide  162  has the second waveguide section  172 , a third bouncing section  183 , and a fourth bouncing section  184 . 
     As viewed in a plan view, the second waveguide section  172  is a portion that does not overlap with the grating section  109  provided on the second cladding layer  108  of the second optical waveguide  162 . The second waveguide section  172  extends from the third bouncing section  183  to the fourth bouncing section  184 . The second waveguide section  172  is inclined with respect to an imaginary straight line (not shown) orthogonal to a third boundary B 3  with the third bouncing section  183 . Similarly, the second waveguide section  172  is inclined with respect to an imaginary straight line (not shown) orthogonal to a fourth boundary B 4  with the fourth bouncing section  184 . Thus, direct multiple reflection between the third bouncing section  183  and the fourth bouncing section  184 , of the light generated in the second waveguide section  172 , can be suppressed. Therefore, formation of a direct resonator can be avoided and laser oscillation of the light generated in the second optical waveguide  162  can be suppressed. 
     As viewed in a plan view, the bouncing sections  183 ,  184  are portions overlapping with the grating section  109  provided on the second cladding layer  108  of the second optical waveguide  162 . The third bouncing section  183  is provided at the end of the second waveguide section  172 , and in the illustrated example, on the side of the first lateral surface  105 . The fourth bouncing section  184  is provided at the other end of the second waveguide section  172 , and in the illustrated example, on the side of the second lateral surface  107 . The bouncing sections  183 ,  184  function as a diffraction grating by the grating section  109 . The bouncing sections  183 ,  184  change the traveling direction of the light guided by the second waveguide section  172  and cause the light to become incident on the lenses  193 ,  194  of the lens array  190 . That is, the bouncing sections  183 ,  184  change the traveling direction of light by diffraction. 
     The optical waveguides  160 ,  162  are provided in a plural number, as shown in  FIG. 1 . In the illustrated example, optical waveguides  160 ,  162  are alternately arrayed in a direction orthogonal to the direction from the first lateral surface  105  to the second lateral surface  107  (in other words, a direction parallel to the in-plane direction of the first lateral surface  105  or the second lateral surface  107 ). 
     The second cladding layer  108  is formed on the active layer  106 , as shown in  FIGS. 3 and 4 . The second cladding layer  108  is, for example, an InGaAlP layer of a second conduction type (for example, p-type). The cladding layers  104 ,  108  are layers with a greater band gap and a lower refractive index than the active layer  106 . The cladding layers  104 ,  108  have the function of preventing leakage of injected carriers (electrons and positive holes) and light from both sides of the active layer  106 . 
     The second cladding layer  108  has plural protrusions  108   a  on an upper surface thereof (surface contacting the contact layer  110 ), as shown in  FIG. 3 . The number of the protrusions  108   a  is not particularly limited. The protrusions  108   a  may have a parallelogrammatic planar shape and a triangular cross-sectional shape, as shown in  FIGS. 2 and 3 . 
     The protrusions  108   a  on the second cladding layer  108  are arrayed along the extending direction of the waveguide sections  170 ,  172  of the optical waveguides  160 ,  162 . The protrusions  108   a  are arranged with the period d=λ=λ 0 /n eff  along the extending direction of the waveguide sections  170 ,  172  (traveling direction of the light guided by the waveguide sections  170 ,  172 ) and form the grating section  109 , as shown in  FIG. 3 . Specifically, each of the protrusions  108   a  has a size of d/2 (that is, λ 0 /(2n eff )) in the extending direction of the waveguide sections  170 ,  172 , and the width between the neighboring protrusions  108   a  is d/2 (that is, λ 0 /(2n eff )). Here, λ 0  represents the wavelength in a vacuum or atmosphere, of the light generated in the optical waveguides  160 ,  162 , and n eff  represents the effective refractive index in a vertical cross section (stacking direction) of the portion where the protrusions  108   a  are provided. 
     With the grating section  109  provided on the second cladding layer  108 , the bouncing sections  181 ,  182 ,  183 ,  184  can function as diffraction gratings and change the traveling direction of the light guided by the waveguide sections  170 ,  172 . 
     The shape of the grating section  109  is not particularly limited as long as the grating section  109  can enable the bouncing sections  181 ,  182 ,  183 ,  184  to function as diffraction gratings. For example, the grating section  109  may have a recess-protrusion shape having a rectangular recess and protrusion, as viewed in a plan view. Also, the grating section  109  may be provided at the boundary between the first cladding layer  104  and the active layer  106  or the boundary between the second cladding layer  108  and the active layer  106 . 
     In the light emitting element  101 , the p-type second cladding layer  108 , the active layer  106  that is not doped with impurities, and the n-type first cladding layer  104  form a pin diode. In the light emitting element  101 , as a forward bias voltage of the pin diode is applied (a current is injected) between the electrodes  120 ,  122 , optical waveguides  160 ,  162  are generated in the active layer  106  and recombination of electrons and positive holes occurs in the optical waveguides  160 ,  162 . This recombination generates light. Starting with the generated light, stimulated emission occurs and the intensity of the light is amplified within the optical waveguides  160 ,  162 . The optical waveguides  160 ,  162  are formed by the active layer  106 , which guides light, and the cladding layers  104 ,  108 , which prevent leakage of light. 
     For example, as shown in  FIG. 3 , light  10  generated in the first waveguide section  170  of the first optical waveguide  160  and propagating toward the first bouncing section  181  is amplified by the first waveguide section  170  and subsequently changes the traveling direction thereof at the first bouncing section  181 . Specifically, the light  10  changes the traveling direction thereof at the first bouncing section  181  and advances toward the second electrode  122  and toward the first electrode  120 . The light  10  may be amplified at the first bouncing section  181 . Similarly, light  12  generated in the first waveguide section  170  and propagating toward the second bouncing section  182  is amplified by the first waveguide section  170  and subsequently changes the traveling direction thereof at the second bouncing section  182 . The light  12  may be amplified at the second bouncing section  182 . 
     Meanwhile, light generated in the second waveguide section  172  of the second optical waveguide  162  and propagating toward the third bouncing section  183  is amplified by the second waveguide section  172  and subsequently changes the traveling direction thereof at the third bouncing section  183 . This light may be amplified at the third bouncing section  183 . Similarly, light generated in the second waveguide section  172  and propagating toward the fourth bouncing section  184  is amplified by the second waveguide section  172  and subsequently changes the traveling direction thereof at the fourth bouncing section  184 . This light may also be amplified at the fourth bouncing section  184 . 
     The contact layer  110  is formed on the second cladding layer  108 , as shown in  FIG. 4 . The contact layer  110  is in ohmic contact with the second electrode  122 . In the illustrated example, the planar shape of the upper surface (a contact surface with the second electrode  122 ) of the contact layer  110  is the same as the planar shape of the optical waveguides  160 ,  162 . The contact layer  110  is, for example, a p-type GaAs layer. 
     The contact layer  110  and a part of the second cladding layer  108  form a pillar-shaped section  112 . The planar shape of the pillar-shaped section  112  is, for example, the same as the planar shape of the optical waveguides  160 ,  162 . The planar shape of the pillar-shaped section  112  determines the current route between the electrodes  120 ,  122 , and consequently determines the planar shape of the optical waveguides  160 ,  162 . Although not shown, a lateral surface of the pillar-shaped section  112  may be inclined. 
     The insulation layer  114  is formed on the second cladding layer  108  and the lateral side of the pillar-shaped section  112  (around the pillar-shaped section  112 , as viewed in a plan view). The insulation layer  114  is in contact with the lateral surfaces of the pillar-shaped section  112 . The upper surface of the insulation layer  114  may continue to the upper surface of the contact layer  110 , as shown in  FIG. 4 . The insulation layer  114  is, for example, a SiN layer, SiO2 layer, SiON layer, Al2O3 layer, or polyimide layer. When these materials are used as the insulation layer  114 , the current between the electrodes  120 ,  122  avoids the insulation layer  114  and flows to the pillar-shaped section  112  held between the insulation layers  114 . 
     The insulation layer  114  has a lower refraction index than the refractive index of the second cladding layer  108 . The effective refractive index of the vertical cross section in the portion where the insulation layer  114  is formed is lower than the effective refractive index of the vertical cross section of the portion where the insulation layer  114  is not formed, that is, the portion where the pillar-shaped section  112  is formed. Thus, in the planar direction, the light can be efficiently confined within the optical waveguides  160 ,  162 . Although not shown, the insulation layer  114  may not be provided. In this case, an air surrounding the pillar-shaped section  112  realizes the similar function to the insulation layer  114 . 
     The first electrode  120  is formed on the entire surface under the substrate  102 . Specifically, the first electrode  120  is formed in contact with the lower surface of the layer (in the illustrated example, the substrate  102 ) that is in ohmic contact with the first electrode  120 . The first electrode  120  is electrically connected to the first cladding layer  104  via the substrate  102 . The first electrode  120  is one electrode for driving the light emitting device  100 . As the first electrode  120 , for example, a Cr layer, an AuGe layer, Ni layer and an Au layer are stacked in this order from the side of the substrate  102 . The first electrode  120  may be composed of other materials capable of transmitting the light generated in the active layer  106 . 
     It is also possible to provide a second contact layer (not shown) between the first cladding layer  104  and the substrate  102 , then expose the surface of this second contact layer opposite to the substrate  102  by dry etching from the side opposite to the substrate  102  or the like, and provide the first electrode  120  on the second contact layer. This can provide a single-sided electrode structure. This configuration is particularly effective in the case where the substrate  102  is insulative. 
     The second electrode  122  is formed on the contact layer  110 . Specifically, the second electrode  122  is formed in contact with the upper surface of the contact layer  110 . The second electrode  122  may also be formed on the insulation layer  114 , as shown in  FIG. 4 . The second electrode  122  is electrically connected to the second cladding layer  108  via the contact layer  110 . The second electrode  122  is the other electrode for driving the light emitting device  100 . As the second electrode  122 , for example, a Cr layer, an AuZn layer and an Au layer are stacked in this order from the side of the contact layer  110 . The second electrode  122  may be composed of other materials capable of transmitting the light generated in the active layer  106 . 
     The wiring substrate  2  supports the light emitting element  101 , as shown in  FIG. 5 . In the example shown in  FIG. 5 , the light emitting element  101  mounted on the wiring substrate  2 , with the side of the second electrode  122  facing the wiring substrate  2  (so-called junction-down mounting). The wiring substrate  2  is formed, for example, by a silicon substrate with wires to be electrically connected to the electrode  120 ,  122 . Although not shown, the light emitting element  101  may be mounted on the wiring substrate  2 , with the side of the first electrode  120  facing the wiring substrate (so-called junction-up mounting). Also, the electrical connection between the wires and the first electrode  120  or the second electrode  122  can be realized by direct contact or via an electrically conductive material such as a solder, sliver paste or gold wire. 
     As shown in  FIG. 5 , in the light emitting element  101  that is mounted by a junction-down mounting, the light traveling toward the first electrode  120  via the bouncing sections  181 ,  182 ,  183 ,  184  is transmitted through the substrate  102  and the first electrode  120  and becomes incident on the lens array  190 . The light traveling toward the second electrode  122  via the bouncing sections  181 ,  182 ,  183 ,  184  may be reflected by the second electrode  122  and reach the lens array  190 . 
     When the substrate  102  and the first electrode  120  are not transparent to the light generated in the optical waveguides  160 ,  162 , the substrate  102  may be eliminated, as shown in  FIG. 6 . When the substrate  102  is a GaAs substrate, for example, the substrate  102  can be eliminated by diluted hydrochloric acid or the like. Although not shown, the first electrode  120  may be formed on a surface of the first cladding layer  104  that does not overlap with the optical waveguides  160 ,  162 , as viewed in a plan view, or may be formed as the above-described single-sided electrode structure. 
     The light emitted from the light emitting element  101  becomes incident on the lens array  190 . The lens array  190  is arranged in the stacking direction of the active layer  106  and the first cladding layer  104  with respect to the light emitting element  101 . In the example shown in  FIG. 5 , the lens array  190  is spaced apart from the light emitting element  101  and provided on the side of the first electrode  120  of the light emitting element  101 . The wiring substrate  2  may have a support member (not shown) to support the lens array  190 . The material of the lens array  190  is glass, for example. 
     The lens array  190  has the first lens  191 , the second lens  192 , the third lens  193  and the fourth lens  194 . The lenses  191 ,  192 ,  193 ,  194  may have the same size and shape as each other. The lenses  191 ,  192 ,  193 ,  194  are, for example, condensing lenses or collimator lenses. The light generated in the active layer  106  becomes incident on the lenses  191 ,  192 ,  193 ,  194 . The light exiting the lenses  191 ,  192 ,  193 ,  194  may be superimposed on each other (partly superimposed). 
     The first lens  191  is provided at a position overlapping with the first bouncing section  181 , as viewed in a plan view, as shown in  FIG. 2 . The light bounced by the first bouncing section  181  (light having the traveling direction changed) becomes incident on the first lens  191 . 
     The second lens  192  is provided at a position overlapping with the second bouncing section  182  and the second waveguide section  172 , as viewed in a plan view. The light bounced by the second bouncing section  182  becomes incident on the second lens  192 . 
     The third lens  193  is provided at a position overlapping with the third bouncing section  183  and the first waveguide section  170 , as viewed in a plan view. The light bounced by the third bouncing section  182  becomes incident on the third lens  193 . 
     The fourth lens  194  is provided at a position overlapping with the fourth bouncing section  184 , as viewed in a plan view. The light bounced by the fourth bouncing section  184  becomes incident on the fourth lens  194 . 
     The lenses  191 ,  192 ,  193 ,  194  are arranged in a staggered form (zigzag form) in the order of the first lens  191 , the third lens  193 , the second lens  192 , and the fourth lens  194  in the direction from the first lateral surface  105  toward the second lateral surface  107 . Thus, the lenses  191 ,  192 ,  193 ,  194  can be arranged with a high density and can illuminate an object with high uniformity, for example, compared with the case where lenses are provided in a matrix form. The distance between the neighboring lenses (for example, the distance between the center of the first lens  191  and the center of the third lens  193  as viewed in a plan view) is approximately 1.5 mm, for example. The lenses  191 ,  192 ,  193 ,  194  are provided in a plural number corresponding to the bouncing sections  181 ,  182 ,  183 ,  184 , as shown in  FIG. 1 . 
     While the AlGaInP-based light emitting element  101  is described above, the light emitting element according to the invention can use any material that enables formation of an optical waveguide. As such a material, for example, semiconductor materials such as AlGaN-based, GaN-based, InGaN-based, GaAs-based, AlGaAs-based, InGaAs-based, InGaAsP-based, InP-based, GaP-based, AlGaP-based, or ZnCdSe-based can be used. 
     In the above, the light emitting element  101  is described as a so-called index-guiding type in which a difference in refractive index is provided between the area where the insulation layer  114  is formed and the area where the insulation layer  114  is not formed, that is, the area where the pillar-shaped section  112  is formed, so as to confine light. However, the light emitting element according to the invention may be a so-called gain-guiding type in which optical waveguides  160 ,  162  generated by injection current function as waveguide areas without providing a difference in refractive index by forming a pillar-shaped section, though not shown. 
     The light emitting device  100  can be applied, for example, to the light source of a projector, display, illumination device, measurement device or the like. 
     The light emitting device  100  has the following features, for example. 
     In the light emitting device  100 , the first optical waveguide  160  has bouncing sections  181 ,  182  that change the traveling direction of the light guided by the first optical waveguide  160 , and the second optical waveguide  162  has the bouncing sections  183 ,  184  that change the traveling direction of the light guided by the second optical waveguide  162 . As viewed in a plane view, the first lens  191  is provided at a position overlapping with the first bouncing section  181 . The second lens  192  is provided at a position overlapping with the second bouncing section  182  and the second optical waveguide  162 . The third lens  193  is provided at a position overlapping with the third bouncing section  183  and the first optical waveguide  160 . The fourth lens  194  is provided at a position overlapping with the fourth bouncing section  184 . In this way, in the light emitting device  100 , three lenses can be arranged to overlap with one optical waveguide, as viewed in a plan view. Specifically, the first optical waveguide  160  overlaps with the lenses  191 ,  192 ,  193 . The second optical waveguide  162  overlaps with the lenses  192 ,  193 ,  194 . Therefore, in the light emitting device  100 , the distance between the lenses  191 ,  192 ,  193 ,  194  can be decreased without reducing the length of the optical waveguides  160 ,  162 , compared with the case where lenses overlap only with both ends of the optical waveguide. 
     In the light emitting device  100 , the bouncing sections  181 ,  182 ,  183 ,  184  change the traveling direction of light by diffraction. Therefore, in the light emitting device  100 , manufacturing cost can be reduced, for example, compared with the case where the traveling direction of light is changed using a prism. Moreover, in the light emitting device  100 , the distance between the optical waveguides  160 ,  162  can be reduced and miniaturization of the device can be realized compared with the case where the traveling direction of light is changed using a prism. 
     1.2. Method for Manufacturing Light Emitting Device 
     Next, a method for manufacturing the light emitting device according to the first embodiment will be described with reference to the drawings.  FIGS. 7 to 9  are cross-sectional views schematically showing the manufacturing process of the light emitting device  100  according to the first embodiment, and corresponding to  FIG. 3 . 
     As shown in  FIG. 7 , the first cladding layer  104 , the active layer  106 , and the second cladding layer  108  are formed on the substrate  102  in this order by epitaxial growth. As a method for epitaxial growth, for example, the MOCVD (metal organic chemical vapor deposition) method or MBE (molecular beam epitaxy) method may be employed. 
     As shown in  FIG. 8 , the second cladding layer  108  is patterned to form plural protrusions  108   a . The patterning is carried out, for example, by photolithography and etching. This process can form the grating section  109 . 
     As shown in  FIG. 9 , the contact layer  110  is formed on the second cladding layer  108  by epitaxial growth. As a method for epitaxial growth, for example, the MOCVD method or MBE method may be employed. 
     As shown in  FIG. 4 , the contact layer  110  and the second cladding layer  108  are patterned. The patterning is carried out, for example, by photolithography and etching. This process can form the pillar-shaped section  112 . 
     Next, the insulation layer  114  is formed to cover the lateral surface of the pillar-shaped section  112 . Specifically, first, an insulation member (not shown) is deposited above the second cladding layer  108  (including the surface on the contact layer  110 ), for example, by the CVD (chemical vapor deposition) method, coating method or the like. Next, the upper surface of the contact layer  110  is exposed, for example, by etching. This process can form the insulation layer  114 . 
     As shown in  FIGS. 3 and 4 , the second electrode  122  is formed on the contact layer  110 . Next, the first electrode  120  is formed below the lower surface of the substrate  102 . The electrodes  120 ,  122  are formed, for example, by the vacuum evaporation method. The order of forming the electrodes  120 ,  122  not particularly limited. This process can form the light emitting element  101 . 
     As shown in  FIG. 5 , the light emitting element  101  is mounted on the wiring substrate  2  in a junction-down manner. Next, the lens array  190  is arranged in such a way that each of the bouncing sections  181 ,  182 ,  183 ,  184  of the light emitting element  101  overlaps with each of the corresponding lenses  191 ,  192 ,  193 ,  194 . 
     This process can produce the light emitting device  100 . 
     1.3. Modifications of Light Emitting Device 
     1.3.1. First Modification 
     Next, a light emitting device according to a first modification of the first embodiment will be described with reference to the drawings.  FIG. 10  is a plan view schematically showing a light emitting device  200  according to the first modification of the first embodiment, and corresponding to  FIG. 2 . 
     Hereinafter, member of the light emitting device  200  according to the first modification of the first embodiment that have similar functions to component members of the light emitting device  100  are denoted by the same reference numerals and will not be described further in detail. 
     In the light emitting device  100 , the first optical waveguide  160  has the bouncing sections  181 ,  182 , and the second optical waveguide  162  has the bouncing sections  183 ,  184 , as shown in  FIG. 2 . Meanwhile, in the light emitting device  200 , the first optical waveguide  160  also has a fifth bouncing section  185 , and the second optical waveguide  162  also has a sixth bouncing section  186 , as shown in  FIG. 10 . 
     The fifth bouncing section  185  is provided at a position overlapping with the third lens  193 , as viewed in a plan view. The fifth bouncing section  185  may have the same shape and the same function as the bouncing sections  181 ,  182 . The fifth bouncing section  185  is provided at a part of the first waveguide section  170 . The first waveguide section  170  extends from the first bouncing section  181  to the fifth bouncing section  185  and further extends from the fifth bouncing section  185  to the second bouncing section  182 . Unlike the bouncing sections  181 ,  182 , the fifth bouncing section  185  bounces only a part of the light and therefore an adjustment can be made thereto, for example, reducing the number of the protrusions  108   a  or the like. 
     The fifth bouncing section  185  changes the traveling direction of a part of the light guided by the first optical waveguide  160 . Specifically, a part of the light guided by the first optical waveguide  160  is bounced by the fifth bouncing section  185  and becomes incident on the third lens  193 . 
     The sixth bouncing section  186  is provided at a position overlapping with the second lens  192 , as viewed in a plan view. The sixth bouncing section  186  may have the same shape and the same function as the bouncing sections  183 ,  184 . Unlike the bouncing sections  183 ,  184 , the sixth bouncing section  186  bounces only a part of the light and therefore an adjustment can be made thereto, for example, reducing the number of the protrusions  108   a  or the like. The sixth bouncing section  186  is provided at a part of the second waveguide section  172 . The second waveguide section  172  extends from the third bouncing section  183  to the sixth bouncing section  186  and further extends from the sixth bouncing section  186  to the fourth bouncing section  184 . 
     The sixth bouncing section  186  changes the traveling direction of a part of the light guided by the second optical waveguide  162 . Specifically, a part of the light guided by the second optical waveguide  162  is bounced by the sixth bouncing section  186  and becomes incident on the second lens  192 . 
     In the light emitting device  200 , the number of light emitting sections in the light emitting element  101  can be increased, compared with the light emitting device  100 . 
     1.3.2. Second Modification 
     Next, a light emitting device according to a second modification of the first embodiment will be described with reference to the drawings.  FIG. 11  is a plan view schematically showing a light emitting device  300  according to the second modification of the first embodiment, and corresponding to FIG.  2 . 
     Hereinafter, members of the light emitting device  300  according to the second modification of the first embodiment that have similar functions to component members of the light emitting device  100  are denoted by the same reference numerals and will not be described further in detail. 
     In the light emitting device  100 , the first optical waveguide  160  has the bouncing sections  181 ,  182 , and the second optical waveguide  162  has the bouncing sections  183 ,  184 , as shown in  FIG. 2 . Meanwhile, in the light emitting device  300 , the first optical waveguide  160  also has a seventh bouncing section  187 , and the second optical waveguide  162  also has a eighth bouncing section  188 , as shown in  FIG. 11 . 
     The seventh bouncing section  187  is provided at a position overlapping with the fourth lens  194 , as viewed in a plan view. The seventh bouncing section  187  may have the same shape and the same function as the bouncing sections  181 ,  182 . Unlike the bouncing sections  181 ,  182 , the seventh bouncing section  187  bounces only a part of the light and therefore an adjustment can be made thereto, for example, reducing the number of the protrusions  108   a  or the like. The first waveguide section  170  extends from the first bouncing section  181  to the second bouncing section  182  and further extends from the second bouncing section  182  to the seventh bouncing section  187 . 
     The seventh bouncing section  187  changes the traveling direction of the light guided by the first optical waveguide  160 . Specifically, the light guided by the first optical waveguide  160  is bounced by the seventh bouncing section  187  and becomes incident on the fourth lens  194 . 
     The eighth bouncing section  188  is provided at a position overlapping with the first lens  191 , as viewed in a plan view. The eighth bouncing section  188  may have the same shape and the same function as the bouncing sections  183 ,  184 . Unlike the bouncing sections  183 ,  184 , the eighth bouncing section  188  bounces only a part of the light and therefore an adjustment can be made thereto, for example, reducing the number of the protrusions  108   a  or the like. The second waveguide section  172  extends from the eighth bouncing section  188  to the third bouncing section  183  and further extends from the third bouncing section  183  to the fourth bouncing section  184 . 
     The eighth bouncing section  188  changes the traveling direction of the light guided by the second optical waveguide  162 . Specifically, the light guided by the second optical waveguide  162  is bounced by the eighth bouncing section  188  and becomes incident on the first lens  191 . 
     In the light emitting device  300 , the length of the optical waveguides  160 ,  162  can be increased, compared with the light emitting device  100 . Therefore, in the light emitting device  300 , light output can be increased. In the light emitting device  300 , the length of the optical waveguides  160 ,  162  is approximately 4.5 mm, for example. 
     1.3.3. Third Modification 
     Next, a light emitting device according to a third modification of the first embodiment will be described with reference to the drawings.  FIG. 12  is a plan view schematically showing a light emitting device  400  according to the third modification of the first embodiment, and corresponding to  FIG. 2 . 
     Hereinafter, members of the light emitting device  400  according to the third modification of the first embodiment that have similar functions to component members of the light emitting device  100  are denoted by the same reference numerals and will not be described further in detail. 
     In the light emitting device  100 , the bouncing sections  181 ,  182 ,  183 ,  184  function as diffraction gratings and change the traveling direction of the light guided by the optical waveguides  160 ,  162 , as shown in  FIG. 2 . Meanwhile, in the light emitting device  400 , the bouncing sections  181 ,  182 ,  183 ,  184  are prisms that change the traveling direction of the light guided by the optical waveguides  160 ,  162 , as shown in  FIG. 12 . The shape of the bouncing sections  181 ,  182 ,  183 ,  184  is not particularly limited as long the bouncing sections can cause the light guided by the optical waveguides  160 ,  162  to become incident on the lenses  191 ,  192 ,  193 ,  194 . 
     In the light emitting element  101  of the light emitting device  400 , a first opening  410  and a second opening  412  are formed. The openings  410 ,  412  are, for example, closed-bottom holes penetrating the light emitting element from the second electrode  122  to the first cladding layer  104 . In the illustrated example, the openings  410 ,  412  have a rectangular shape, as viewed in a plan view. The openings  410 ,  412  may be formed by patterning based on photolithography and etching. 
     In the light emitting device  400 , the first waveguide section  170  of the first optical waveguide  160  extends from the first lateral surface  105  to the first opening  410 . In the illustrated example, the first bouncing section  181  is provided in contact with the first lateral surface  105 . The second bouncing section  182  is provided in contact with the inner surface of the first opening  410 . 
     In the light emitting device  400 , the second waveguide section  172  of the second optical waveguide  162  extends from the second opening  412  to the second lateral surface  107 . In the illustrated example, the third bouncing section  183  is provided in contact with the inner surface of the second opening  412 . The fourth bouncing section  184  is provided in contact with the second lateral surface  107 . 
     In the light emitting device  400 , as in the light emitting device  100 , the distance between the lenses  191 ,  192 ,  193 ,  194  can be decreased without reducing the length of the optical waveguides  160 ,  162 . 
     2. Second Embodiment 
     2.1. Light Emitting Device 
     Next, a light emitting device according to a second embodiment will be described with reference to the drawings. 
       FIGS. 13 and 14  are plan views schematically showing a light emitting device  500  according to the second embodiment. In  FIGS. 13 and 14 , the second electrode  122  is omitted and a part of the lens array  190  is shown perspectively.  FIG. 14  is an enlarged view of a part of the light emitting device  500  shown in  FIG. 13 . 
     Hereinafter, member of the light emitting device  500  according to the second embodiment that have similar functions to component members of the light emitting devices  100 ,  200 ,  300  are denoted by the same reference numerals and will not be described further in detail. 
     In the light emitting device  100 , the first optical waveguide  160  and the second optical waveguide  162  are spaced apart from each other, as shown in  FIGS. 1 and 2 . Meanwhile, in the light emitting device  500 , the first optical waveguide  160  and the second optical waveguide  162  are integrally formed, as shown in  FIGS. 13 and 14 . It can also be said that the optical waveguides  160 ,  162  contact each other and form a single optical waveguide. The optical waveguides  160 ,  162  are integrally formed, thus forming an integrated optical waveguide  560 . 
     In the light emitting device  500 , the first optical waveguide  160  has the bouncing sections  181 ,  182 ,  185 ,  187 , as shown in  FIG. 14 . The first waveguide section  170  extends from the first bouncing section  181  to the fifth bouncing section  185 , then extends from the fifth bouncing section  185  to the second bouncing section  182 , and further extends from the second bouncing section  182  to the seventh bouncing section  187 . 
     In the light emitting device  500 , the second optical waveguide  162  has the bouncing sections  183 ,  184 ,  186 ,  188 . The second waveguide section  172  extends from the eighth bouncing section  188  to the third bouncing section  183 , then extends from the third bouncing section  183  to the sixth bouncing section  186 , and further extends from the sixth bouncing section  186  to the fourth bouncing section  184 . 
     The first waveguide section  170  and the second waveguide section  172  are integrally formed, thus forming an integrated waveguide section  570 . The first bouncing section  181  and the eighth bouncing section  188  are integrally formed, thus forming a first integrated bouncing section  581 . The third bouncing section  183  and the fifth bouncing section  185  are integrally formed, thus forming a second integrated bouncing section  582 . The second bouncing section  182  and the sixth bouncing section  186  are integrally formed, thus forming a third integrated bouncing section  583 . The fourth bouncing section  184  and the seventh bouncing section  187  are integrally formed, thus forming a fourth integrated bouncing section  584 . 
     The second integrated bouncing section  582  has a smaller width than the width of the integrated waveguide section  570  (the size in the direction orthogonal to the extending direction of the waveguide sections  170 ,  172 ). The third integrated bouncing section  583  has a smaller width than the integrated waveguide section  570 . In the illustrated example, the second integrated bouncing section  582  is provided in contact with a boundary (boundary along the longitudinal direction) B 5  on one side of the integrated waveguide section  570 , and the third integrated bouncing section  583  is provided in contact with a boundary (boundary along the longitudinal direction) B 6  on the other side of the integrated waveguide section  570 . Thus, direct multiple reflection between the second integrated bouncing section  582  and the third integrated bouncing section  583 , of the light generated in the integrated optical waveguide  560 , can be suppressed. Therefore, formation of a direct resonator can be avoided and laser oscillation of the light generated in the integrated optical waveguide  560  can be suppressed. Although not shown, the width of the integrated bouncing sections  582 ,  583  may be the same as the width of the integrated optical waveguide  560 . 
     In the light emitting device  500 , as in the light emitting device  100 , the distance between the lenses  191 ,  192 ,  193 ,  194  can be decreased without reducing the length of the optical waveguides  160 ,  162 . 
     2.2. Method for Manufacturing Light Emitting Device 
     The method for manufacturing the light emitting device  500  according to the second embodiment is basically the same as the method for manufacturing the light emitting device  100  according to the first embodiment and therefore will not be described further in detail. 
     2.3. Modification of Light Emitting Device 
     Next, a light emitting device according to a modification of the second embodiment will be described with reference to the drawings.  FIG. 15  is a plan view schematically showing a light emitting device  600  according to the modification of the second embodiment, and corresponding to  FIG. 14 . 
     Hereinafter, member of the light emitting device  600  according to the modification of the second embodiment that have similar functions to component members of the light emitting devices  400 ,  500  are denoted by the same reference numerals and will not be described further in detail. 
     In the light emitting device  500 , the integrated bouncing sections  581 ,  584  function as diffraction gratings and change the traveling direction of the light guided by the integrated optical waveguide  560 , as shown in  FIG. 14 . Meanwhile, in the light emitting device  600 , the integrated bouncing sections  581 ,  584  are prisms that change the traveling direction of the light guided by the integrated optical waveguide  560 , as shown in  FIG. 15 . In the illustrated example, the first integrated bouncing section  581  is provided in contact with the first lateral surface  105 . The fourth integrated bouncing section  584  is provided in contact with the second lateral surface  107 . 
     In the light emitting device  600 , as in the light emitting device  500 , the distance between the lenses  191 ,  192 ,  193 ,  194  can be decreased without reducing the length of the optical waveguides  160 ,  162 . 
     3. Third Embodiment 
     Next, a projector according to a third embodiment will be described with reference to the drawings.  FIG. 16  schematically shows a projector  700  according to the third embodiment. In  FIG. 16 , for convenience, a casing that forms the projector  700  is omitted and the light emitting device  100  is simplified. 
     The projector  700  includes a red light source  100 R, a green light source  100 G, and a blue light source  100 B that emit red light, green light, and blue light, respectively, as shown in  FIG. 16 . The red light source  100 R, the green light source  100 G and the blue light source  100 B are light emitting devices according to the invention. Hereinafter, an example using the light emitting device  100  as a light emitting device according to the invention will be described. 
     The projector  700  includes the light emitting devices  100  (light sources  100 R,  100 G,  100 B), transmission-type liquid crystal light valves (light modulation devices)  704 R,  704 G,  704 B, and a projection lens (projection device)  708 . 
     The light emitted from the light sources  100 R,  100 G,  100 B becomes incident on the respective liquid crystal light valves  704 R,  704 G,  704 B. Each of the respective liquid crystal light valves  704 R,  704 G,  704 B modulates the incident light according to image information. The projection lens  708  magnifies and projects images formed by the liquid crystal light valves  704 R,  704 G,  704 B on a screen (display surface)  710 . 
     The projector  700  also include a cross dichroic prism (color combining unit)  706  that combines the light emitted from the liquid crystal light valves  704 R,  704 G,  704 B and guides the combined light to the projection lens  708 . 
     The three color light beams modulated by the respective liquid crystal light valves  704 R,  704 G,  704 B become incident on the cross dichroic prism  706 . The cross dichroic prism.  706  is formed by four right-angled prisms bonded together, and a dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light are arranged on the inner surfaces of the prisms in a cruciform. The three color beams are combined by these dielectric multilayer films, thus forming light that represents a color image. The combined light is projected on the screen  710  by the projection lens  708  composing a projection optical system. Thus, an enlarged image is displayed. 
     The projector  700  can include the light emitting device  100  in which the distance between the lenses  191 ,  192 ,  193 ,  194  can be decreased without reducing the length of the optical waveguides  160 ,  162 . 
     The projector  700  employs an optical system in which the light emitting device  100  is arranged directly below the liquid crystal light valve  704  so that condensing of light and uniform illumination are simultaneously carried out using the lens array  190  of the light emitting device  100  (backlight system). Therefore, in the projector  700 , reduction in loss and reduction in the number of components in the optical system can be achieved. 
     In the above example, the transmission-type liquid crystal light valves are used as light modulation devices. However, other types of light valves than liquid crystal or reflection-type light valves may be used. Such light valves may be, for example, reflection-type liquid crystal light valves or digital micromirror devices. The configuration of the projection optical system may be changed properly according to the type of the light valves to be used. 
     The light emitting device  100  can also be applied to the light source of a scanning-type image display device (projector) in which the light from the light emitting device  100  is swept to display an image with a desired size on a screen. 
     The embodiments and modifications are non-limiting examples. For example, each of the embodiments and modifications can be suitably combined. 
     The invention includes substantially the same configurations as the configurations described in the embodiments (for example, a configuration with the same function, method and result, or a configuration with the same objective and effect). The invention also includes configurations in which a non-essential part of the configurations described in the embodiments is replaced. The invention also includes configurations that have the same advantageous effects as the configurations described in the embodiments, or configurations that can achieve the same objective. Moreover, the invention includes configurations in which a known technique is added to the configurations described in the embodiments. 
     The entire disclosure of Japanese Patent Application No. 2013-179094, filed Aug. 30, 2013 is expressly incorporated by reference herein.