JP6868865B2 - Lighting device - Google Patents

Description

The present invention relates to lighting devices such as vehicle headlights.

ADB (adaptive driving beam) vehicle headlights are an example of headlamps that can dynamically control the illumination light. In general, dynamically controlled lighting includes basic lighting required for vehicle headlights, lighting directed to a specific object, lighting for displaying information on the road surface, and the like. Is done. Their basic technology is spatial modulation of light, which is common to, for example, widely used projectors. Dynamic illumination light control can be performed by an LCD (liquid crystal display) panel, an LCOS (liquid crystal on silicon) panel, a DLP (digital light processing), a MEMS (microelectromechanical systems) mirror, or the like. For example, from the viewpoint of light utilization efficiency, it is preferable to use a mirror whose inclination with respect to incident light can be changed, such as a MEMS mirror. In the method of forming the illumination light by reflecting the light emitted from the light source by using a mirror such as a MEMS mirror, for example, the light beam required for the illumination is emitted while scanning directly toward the front of the vehicle. A method of forming a desired illumination light pattern and a desired illumination light corresponding pattern are formed by scanning a light beam on a panel (such as a phosphor panel) having a light wavelength conversion action, and the desired illumination light corresponding pattern is formed in front of the vehicle by a lens. There is a method of projecting to.

Various inventions relating to headlights are known (see, for example, Patent Documents 1 and 2). Patent Document 1 describes an invention of a headlight capable of suppressing an increase in size and reducing power consumption and forming a desired shade in an illumination light pattern. Patent Document 2 describes the invention of a headlight having high color rendering properties and capable of realizing an arbitrary projection pattern.

In the headlight described in Patent Document 1, two movable mirrors are used for controlling the emission direction of the laser beam (scanning of the laser beam). Since it involves mechanically moving parts, there are problems in the size, weight, light distribution accuracy, reliability, life, etc. of the headlight.

Further, in addition to the laser driver that controls the emission of the laser beam, a driver that controls the operation of the two movable mirrors is required. Further, a configuration for monitoring the emission direction of the laser beam emitted from the movable mirror may be required.

The reflectance of the mirror is also an issue. The decrease in reflectance not only leads to a decrease in the brightness of the illumination light, but also causes thermal stress on the mirror itself, which greatly affects its reliability and life.

Further, since the illumination region is scanned by a single laser beam, the wider the illumination region is, the lower the time density at which the laser beam is incident on the central portion of the illumination region. Therefore, the central portion of the light distribution (illumination range) may be darker than the peripheral portion. In scanning a predetermined range, it may be difficult to handle partial scanning.

Since the laser light emitted from a normal laser light source has a spread at a certain angle, it may be necessary to collimate using an optical system such as a lens before incidenting the laser light on the scanner.

Research on photonic crystal lasers has been made (see, for example, Patent Documents 3 and 4). Patent Document 3 discloses an invention of a photonic crystal laser capable of stably emitting a laser beam (inclined beam) at an inclination angle of a maximum of 45 °. Patent Document 4 discloses an invention of a photonic crystal laser capable of increasing the inclination angle of laser beam emission and having a high degree of freedom in designing a two-dimensional photonic crystal layer.

Japanese Unexamined Patent Publication No. 2011-157022 Japanese Unexamined Patent Publication No. 2013-232390 Japanese Patent No. 57946687 Japanese Unexamined Patent Publication No. 2013-21152

An object of the present invention is to provide a high quality lighting device.

According to one aspect of the present invention, a first photonic crystal laser that y de laser light of a first color, the second photonic crystal morphism exiting the laser light of the second color different from said first color laser and, have a first control device for controlling the emission of the laser beam from the first photonic crystal laser and said second photonic crystal laser, the first photonic crystal laser and said second photonic crystal Each laser has a plurality of electrodes electrically separated from each other so that the laser beam is emitted in a predetermined direction in each of the plurality of regions of the photonic crystal layer corresponding to the plurality of electrodes. The first control device controls the balance of the voltages applied to the plurality of electrodes to obtain the tilted nuclei θ of the laser light from the first photonic crystal laser and the second photonic crystal laser. A vehicle headlight is provided which changes the rotation angle φ of the emission azimuth surface Ps and scans the laser beam in the elliptical region.

According to the present invention, it is possible to provide a high quality lighting device.

1A to 1C are schematic cross-sectional views showing a structural example of a photonic crystal laser. 2A and 2B are schematic views showing the laser beams α and β emitted from the photonic crystal lasers 41, 42 and 43, and FIG. 2C shows the lasers emitted from the photonic crystal lasers 41, 42 and 43. It is a schematic diagram which shows the light. 3A and 3B are schematic views showing the laser beams α and β and the emission directional plane Ps. FIG. 4 is a schematic view showing an example of laser light emission control. FIG. 5 is a schematic view showing a control example of simultaneously irradiating laser light. 6A to 6D are schematic plan views showing the configuration of the AlGaInP photonic crystal layer 3 of the photonic crystal laser 41. 7A and 7B are schematic plan views showing an arrangement example of the n-side electrode 9 and the p-side electrode 8 in the photonic crystal laser 41, respectively, and FIG. 7C is an emission azimuth plane having an azimuth angle of φ = 0 °. It is a graph which shows the relationship between the inclination angle θ and the parameters r ₁ and r _{2 when the laser beam is emitted inside.} 8A and 8B are schematic plan views showing other arrangement examples of the n-side electrode 9 and the p-side electrode 8 in the photonic crystal laser 41, respectively. 9A and 9B are schematic plan views showing still another arrangement example of the n-side electrode 9 and the p-side electrode 8 in the photonic crystal laser 41, respectively. 10A and 10B show the relationship between _{the inclination angle θ and the parameters r 1} and r _{2 when} the photonic crystal lasers 42 and 43 emit laser light in the emission azimuth plane having an azimuth angle φ = 0 °, respectively. It is a graph. 11A is a schematic view showing a basic configuration of a lighting device according to an embodiment, FIG. 11B is a schematic view showing a photonic crystal laser 30, and FIG. 11C is a red, green, and blue light emitting unit 30R. It is the schematic which shows the red light, green light, and blue light which emitted 30G, 30B. 12A is a schematic view showing a vehicle headlight according to an embodiment, FIG. 12B is a schematic perspective view showing a beam shaping diffraction element 31, and FIG. 12C is a plurality of photonic crystal laser modules. It is the schematic which shows the structure to be provided. FIG. 13 is a schematic view showing an application example of the lighting device according to the embodiment.

The photonic crystal laser, for example, uses the group velocity zero effect at the band end of a two-dimensional photonic crystal to form a standing wave resonance state in the plane, and diffracts a part of it in the direction perpendicular to the in-plane direction. It is a laser that obtains output by making it. It has a structure different from that of ordinary semiconductor lasers that emit end face light and surface emitting lasers such as VCSELs (vertical cavity surface emitting lasers), and is excellent in output and beam quality.

The photonic crystal laser used in the lighting device according to the embodiment will be described.

FIG. 1A is a schematic cross-sectional view showing an example of a structure of a photonic crystal laser. The photonic crystal laser 41 shown in this figure is, for example, a chip-shaped photonic crystal laser that emits light in the red wavelength region.

The photonic crystal laser 41 includes, for example, an n-type AlGaInP clad layer 2, an AlGaInP photonic crystal layer 3, and a GaInP / AlGaInP quantum well active layer 4 laminated on an n-type GaAs substrate 1 and an n-type GaAs substrate 1 in this order. , AlGaInP guide layer 5, p-type AlGaInP clad layer 6, and p-type GaAs contact layer 7. The n-side electrode 9 is arranged on the surface of the n-type GaAs substrate 1 opposite to the laminated structure. The p-side electrode 8 is arranged on the surface of the p-type GaAs contact layer 7 opposite to the p-type AlGaInP clad layer 6.

The photonic crystal laser 41 can be manufactured, for example, by the following method.

First, the n-type AlGaInP clad layer 2 and the AlGaInP layer are grown on the n-type GaAs substrate 1 by using the metal organic chemical vapor deposition (MOCVD) method.

_{A SiN x} film is formed on the AlGaInP layer by using a plasma CVD (chemical vapor deposition) method. A resist (for example, ZEP520A manufactured by Zeon Corporation) is applied onto the _{SiN x film by spin coating.}

The desired photonic crystal pattern is exposed using electron beam lithography.

After exposure, it is developed using a developing solution (for example, ZED-N50 manufactured by Nippon Zeon Corporation).

Using the patterned resist as a mask, the SiN _x film is etched with a dry etcher, and the pattern is transferred to the _{SiN x film.}

The resist (ZEP520A) is removed using a stripping solution (for example, ZDMAC manufactured by Nippon Zeon Corporation).

Using the SiN _x film as a mask, pores are formed in the AlGaInP layer by dry etching.

The SiN _x membrane is removed with buffered HF (hydrofluoric acid).

It is put into the MOCVD apparatus again, embedded and regrown so as to leave holes.

Up to this step, the AlGaInP photonic crystal layer 3 is formed.

The GaInP / AlGaInP quantum well active layer 4 (well layer: GaInP, barrier layer: AlGaInP), AlGaInP guide layer 5, p-type AlGaInP clad layer 6, and p-type GaAs contact layer 7 are grown in the MOCVD apparatus as they are.

It is taken out from the MOCVD apparatus, electrodes 8, 9 and the like are formed, and cut into chips.

Through such a process, the photonic crystal laser 41 is manufactured.

The above-mentioned method is a manufacturing method by regrowth. For example, a photonic crystal laser having a structure in which a laminated structure is arranged between an n-type GaAs substrate and a p-type GaAs substrate using a p-type GaAs substrate is manufactured by a method of fusing (bonding) two substrates. You can also do it. In addition, since the production method by fusion increases the occurrence of crystal defects, it is preferable to produce by using the regrowth method.

Further, in the configuration shown in FIG. 1A, the photonic crystal layer 3 is provided on the n side, but it may be arranged on the p side. In this case, the laminated structure is, for example, the n-type AlGaInP clad layer, the n-type AlGaInP crystal layer, the GaInP / AlGaInP quantum well active layer, the p-type AlGaInP photonic crystal layer, and the p-type AlGaInP clad layer in order from the n-type GaAs substrate 1 side. , P-type GaAs contact layer.

Further, the semiconductor layer may be grown by another method, for example, a molecular beam epitaxy (MBE) method, instead of the MOCVD method.

Further, the SiO ₂ film may be used instead of the SiN _{x film.} It can also be formed by using a sputtering method or a vapor deposition method instead of the plasma CVD method.

By applying a voltage between the electrodes 8 and 9 of the photonic crystal laser 41 and supplying a current to the GaInP / AlGaInP quantum well active layer 4, laser light (laser beam) is emitted from the n-type GaAs substrate 1 side. .. The emitted laser light is, for example, light having a wavelength of 650 nm (red wavelength region). If the laser structure emits red light, the substrate, the laminated structure, and the like may be formed of other materials.

In the specification and drawings of the present application, the X-axis and the Y-axis are defined in the plane of the photonic crystal laser (in the plane of the photonic crystal layer). Further, the Z-axis is defined in a direction parallel to the in-plane normal direction of the photonic crystal laser (normal direction of the photonic crystal layer), and the side on which the laser beam is emitted is the Z-axis positive direction.

FIG. 1B is a schematic cross-sectional view showing another structural example of the photonic crystal laser. The photonic crystal laser 42 shown in this figure is, for example, a chip-shaped photonic crystal laser that emits light in the green wavelength region.

The photonic crystal laser 42 includes, for example, an n-type GaN substrate 10, an n-type AlGaN clad layer 11, an n-type GaN photonic crystal layer 12, and an InGaN / InGaN quantum well activity laminated on the n-type GaN substrate 10 in this order. It has a laminated structure of layer 13, non-doped GaN layer 14, p-type AlGaN electron block layer 15, p-type AlGaN clad layer 16, and p-type GaN contact layer 17. The n-side electrode 19 is arranged on the surface of the n-type GaN substrate 10 opposite to the laminated structure. The p-side electrode 18 is arranged on the surface of the p-type GaN contact layer 17 opposite to the p-type AlGaN clad layer 16.

The photonic crystal laser 42 can be manufactured, for example, by the following method.

First, the n-type AlGaN clad layer 11 and the n-type GaN layer are grown on the n-type GaN substrate 10 by using the MOCVD method.

_{A SiN x} film is formed on the n-type GaN layer by using the plasma CVD method. A resist (for example, ZEP520A manufactured by Zeon Corporation) is applied onto the _{SiN x film by spin coating.}

The desired photonic crystal pattern is exposed using electron beam lithography.

After exposure, it is developed using a developing solution (for example, ZED-N50 manufactured by Nippon Zeon Corporation).

Using the patterned resist as a mask, the SiN _x film is etched with a dry etcher, and the pattern is transferred to the _{SiN x film.}

The resist (ZEP520A) is removed using a stripping solution (for example, ZDMAC manufactured by Nippon Zeon Corporation).

Using the SiN _x film as a mask, pores are formed in the GaN layer by dry etching.

The SiN _x membrane is removed with buffered HF (hydrofluoric acid).

It is put into the MOCVD apparatus again, embedded and regrown so as to leave holes.

Up to this step, the n-type GaN photonic crystal layer 12 is formed.

In GaN / InGaN quantum well active layer 13 (well layer: InGaN, barrier layer: InGaN), non-doped GaN layer 14, p-type AlGaN electron block layer 15, p-type AlGaN clad layer 16, p-type GaN contact in the MOCVD apparatus as it is. Layer 17 is grown.

It is taken out from the MOCVD apparatus, electrodes 18, 19 and the like are formed, and the chips are cut out.

Through such a process, the photonic crystal laser 42 is manufactured.

In the configuration shown in FIG. 1B, the photonic crystal layer 12 is provided on the n side, but it may be arranged on the p side.

Further, the semiconductor layer can be grown by using another method, for example, the MBE method, instead of the MOCVD method.

Further, a SiO ₂ film may be used _{instead of the SiN x film.} It can also be formed by using a sputtering method or a vapor deposition method instead of the plasma CVD method.

The InGaN / InGaN quantum well active layer 13 may be an InGaN / GaN quantum well active layer (well layer: InGaN, barrier layer: GaN).

By applying a voltage between the electrodes 18 and 19 of the photonic crystal laser 42 and supplying a current to the InGaN / InGaN quantum well active layer 13, laser light (laser beam) is emitted from the n-type GaN substrate 10 side. .. The emitted laser light is light having a wavelength of 560 nm (green wavelength region). If the laser structure emits green light, another material may be used. For example, the laminated structure on the n-type GaN substrate 10 is arranged in order from the n-type GaN substrate 10 side, an n-type GaN clad layer, an InGaN photonic crystal layer, an InGaN / InGaN quantum well active layer, an InGaN guide layer, and a p-type AlGaN electron. It can be a block layer, a p-type GaN clad layer, or a p-type GaN contact layer.

FIG. 1C is a schematic cross-sectional view showing still another structural example of the photonic crystal laser. The photonic crystal laser 43 shown in this figure is, for example, a chip-shaped photonic crystal laser that emits light in a blue wavelength region.

The photonic crystal laser 43 includes, for example, an n-type GaN substrate 20, an n-type AlGaN clad layer 21, an n-type GaN photonic crystal layer 22, and an InGaN / GaN quantum well activity laminated on the n-type GaN substrate 20 in this order. It has a laminated structure of a layer 23, a non-doped GaN layer 24, a p-type AlGaN electron block layer 25, a p-type AlGaN clad layer 26, and a p-type GaN contact layer 27. The n-side electrode 29 is arranged on the surface of the n-type GaN substrate 20 opposite to the laminated structure. The p-side electrode 28 is arranged on the surface of the p-type GaN contact layer 27 opposite to the p-type AlGaN clad layer 26.

The photonic crystal laser 43 can be manufactured, for example, by the following method.

First, the n-type AlGaN clad layer 21 and the n-type GaN layer are grown on the n-type GaN substrate 20 by using the MOCVD method.

_{A SiN x} film is formed on the n-type GaN layer by using the plasma CVD method. A resist (for example, ZEP520A manufactured by Zeon Corporation) is applied onto the _{SiN x film by spin coating.}

The desired photonic crystal pattern is exposed using electron beam lithography.

After exposure, it is developed using a developing solution (for example, ZED-N50 manufactured by Nippon Zeon Corporation).

Using the patterned resist as a mask, the SiN _x film is etched with a dry etcher, and the pattern is transferred to the _{SiN x film.}

The resist (ZEP520A) is removed using a stripping solution (for example, ZDMAC manufactured by Nippon Zeon Corporation).

Using the SiN _x film as a mask, pores are formed in the GaN layer by dry etching.

The SiN _x membrane is removed with buffered HF (hydrofluoric acid).

It is put into the MOCVD apparatus again, embedded and regrown so as to leave holes.

Up to this step, the n-type GaN photonic crystal layer 22 is formed.

In GaN / GaN quantum well active layer 23 (well layer: InGaN, barrier layer: GaN), non-doped GaN layer 24, p-type AlGaN electron block layer 25, p-type AlGaN clad layer 26, p-type GaN contact in the MOCVD apparatus as it is. Layer 27 is grown.

It is taken out from the MOCVD apparatus, electrodes 28, 29 and the like are formed, and cut into chips.

Through such a process, the photonic crystal laser 43 is manufactured.

In the configuration shown in FIG. 1C, the photonic crystal layer 22 is provided on the n side, but it may be arranged on the p side.

Further, the semiconductor layer can be grown by using another method, for example, the MBE method, instead of the MOCVD method.

Further, a SiO ₂ film may be used _{instead of the SiN x film.} It can also be formed by using a sputtering method or a vapor deposition method instead of the plasma CVD method.

The InGaN / GaN quantum well active layer 23 may be an InGaN / InGaN quantum well active layer (well layer: InGaN, barrier layer: InGaN).

By applying a voltage between the electrodes 28 and 29 of the photonic crystal laser 43 and supplying a current to the InGaN / GaN quantum well active layer 23, laser light (laser beam) is emitted from the n-type GaN substrate 20 side. .. The emitted laser light is light having a wavelength of 450 nm (blue wavelength region). If the laser structure emits blue light, another material may be used.

FIG. 2A shows the laser beams α and β emitted from the photonic crystal lasers 41, 42 and 43. In the photonic crystal lasers 41, 42, and 43, two laser beams (double beam) α and β are simultaneously emitted from one laser beam emission position O. The angle formed by the emission direction of the laser beam α and the in-plane normal direction of the photonic crystal lasers 41, 42, 43 (the normal direction of the photonic crystal layers 3, 12, 22) and the emission of the laser beam β. The angle formed by the direction and the in-plane normal direction of the photonic crystal lasers 41, 42, 43 (the normal direction of the photonic crystal layers 3, 12, 22) is equal to each other. Hereinafter, this angle is referred to as an inclination angle θ. The inclination angle θ is an inclination angle formed by the emission directions of the laser beams α and β with respect to the normals of the photonic crystal layers 3, 12, and 22.

Further, the outputs of the laser beam α and the laser beam β are equal to each other.

See FIG. 2B with FIG. 2A. The emission directions of the laser beams α and β are directions in one plane Ps orthogonal to the emission planes of the photonic crystal lasers 41, 42 and 43 (photonic crystal layers 3, 12 and 22 planes). Emission directions of laser beams α and β starting from the laser beam emission position O and in-plane normal directions of the photonic crystal lasers 41, 42 and 43 (normal directions of the photonic crystal layers 3, 12 and 22). Can also be said to be all in-plane directions of the plane Ps. In the examples shown in FIGS. 2A and 2B, the emission directions of the laser beams α and β are in-plane directions of the plane Ps parallel to the XZ plane including the laser light emission position O. Hereinafter, the emission directions of the laser beams α and β starting from the laser beam emission position O and the in-plane normal directions of the photonic crystal lasers 41, 42 and 43 (normals of the photonic crystal layers 3, 12 and 22). The plane Ps whose all directions are in-plane directions is called an exit azimuth plane Ps.

See FIG. 2C. The laser light of the photonic crystal lasers 41, 42, 43 is emitted from within the range of several hundred μm × several hundred μm in the plane of the photonic crystal lasers 41, 42, 43, for example. The spread angle of one laser beam is, for example, about 1 °. The total output of the two laser beams (double beam) is, for example, 1W to 10W. Further, for example, by repeatedly turning on and off the currents supplied to the quantum well active layers 4, 13 and 23, a pulse wave (pulse laser beam) up to a repetition frequency (pulse modulatorable frequency) of several hundred MHz is emitted. Can be done. If the current supply is continued without interruption, a continuous wave laser beam is emitted.

The photonic crystal lasers 41, 42, and 43 used in the lighting device according to the embodiment described later have the above-mentioned characteristics and can, for example, perform the following laser light control (emission beam control).

See FIG. 3A. The inclination angle θ can be arbitrarily changed within the range of 0 ° ≦ θ ≦ 45 °.

See FIG. 3B. The emission azimuth plane Ps passes through the laser beam emission position O and is a straight line orthogonal to the in-plane direction of the photonic crystal lasers 41, 42, 43 (a straight line parallel to the normal direction of the photonic crystal layers 3, 12, 22). Can be rotated at any angle around the axis.

Combining the change in the tilt angle θ with the change in the rotation angle of the exit azimuth surface Ps (when both the tilt angle θ and the rotation angle of the exit azimuth surface Ps are controlled), the laser in the cone whose apex is the laser beam emission position O. Light scanning (irradiation of laser light to an arbitrary position) becomes possible, and for example, an arbitrary range within an elliptical region can be illuminated.

Along with scanning the laser beam (reciprocating, rotating, etc.), for example, pulse width modulation (PWM) or blinking frequency (pulse frequency modulation; PFM) of the laser beam may be performed. Output (strength) control is also possible.

In the example shown in FIG. 4, for example, when scanning (illuminating) the inside of an elliptical region, the output p2 of the laser light irradiating the central portion of the ellipse is larger than the output p1 of the laser light irradiating the left and right regions of the ellipse. Increase (p1 <p2). Separately or in combination with this, the frequency f2 of the laser light irradiating the central portion of the ellipse is made smaller than the frequency f1 of the laser light irradiating the left and right regions of the ellipse (f2 <f1). In this way, for example, the output and frequency of the laser beam are controlled according to the incident position. For example, in a vehicle headlight, it is preferable that the output p2 of the laser light incident on the central portion of the irradiation range is larger than the output p1 of the laser light incident on the left and right regions. The frequencies f1 and f2 may be equal in the central portion and the left and right regions.

By controlling the emission of laser light (controlling the tilt angle θ, the rotation angle of the emission azimuth surface Ps, the laser light output, the blinking frequency, the pulse width, etc.), for example, the shape of the illumination area (illumination range) and illumination The light intensity distribution can be controlled (dynamic formation of illumination patterns). As will be described later, the emission control of the laser beam is performed, for example, by controlling the mode of applying the voltage to the electrodes (including the selection of the electrode to which the voltage is applied).

Further, in the photonic crystal lasers 41, 42, 43, it is possible to independently control a plurality of twin beams. For example, two sets of twin beams can be emitted at the same time, and the inclination angle θ, the rotation angle of the exit directional plane Ps, the laser beam output, the blinking frequency, the pulse width, and the like can be independently changed for each set.

Strictly speaking, laser light having different inclination angles θ and rotation angles of the emission directional planes Ps is not emitted from the same emission position, and there is a displacement of the emission position according to θ and Ps. Such a displacement is, for example, on the order of nm to μm, and is so large that it cannot be represented by a diagram such as FIGS. 3A, 3B, 4 and 5 (described later). Moreover, such displacement does not pose a problem in a lighting device that controls the arrival position of the laser beam, such as the headlight (described later) of the present case.

FIG. 5 shows an example in which a plurality of sets (4 sets) of twin beams having different inclination angles θ are simultaneously emitted. The emission directions of the four sets of twin beams are all in-plane directions of the plane Ps. Simultaneous multipoint irradiation is possible by emitting a plurality of twin beams at the same time. Due to the effect of simultaneous irradiation, the band-shaped region can be irradiated with laser light. It is also possible to control the output of the laser beam while keeping the lights on at the same time. It is also possible to perform blinking frequency control, pulse width control, and the like.

The tilt angle θ control of the laser beam and the rotation angle control of the emission directional plane Ps will be described in detail.

6A to 6D are schematic plan views showing the configuration of the AlGaInP photonic crystal layer 3 of the photonic crystal laser 41. The tilt angle θ control of the laser beam and the rotation angle control of the emission directional plane Ps can be performed by adopting, for example, the same configuration as the configuration of the two-dimensional photonic crystal layer described in Patent Document 4.

The AlGaInP photonic crystal layer 3 is formed by arranging pores (regions having a refractive index different from that of the base material) in a layered base material (AlGaInP layer) to form a photonic crystal structure for forming an optical resonance state. It has an optical resonance state forming lattice 3a (see FIG. 6A) and a light emitting lattice 3b (see FIG. 6B) forming a photonic crystal structure for emitting light.

See FIG. 6A. The optical resonance state forming lattice 3a is composed of a square lattice having a lattice constant a, and the lattice points 3a ₁ are arranged at intervals a along the X-axis direction and the Y-axis direction.

See FIG. 6B. The light emitting lattice 3b (lattice point 3b ₁ ) constitutes an orthorhombic lattice having the basic translation vectors of (r ₁ , 1) a and (r _{2, 1) a.}

See FIGS. 6C and 6D. The AlGaInP photonic crystal layer 3 has a structure in which a lattice for forming an optical resonance state 3a and a lattice for emitting light 3b are superposed. The pores 3d are arranged at _{the lattice points 3c 1} of the lattice 3c of the photonic crystal.

For example, red laser beams α and β having a wavelength of 650 nm are emitted from the photonic crystal laser 41. _{The effective refractive index n eff} of the AlGaInP photonic crystal layer 3 is determined by the refractive index of AlGaInP forming the base material and the ratio of the pores 3d in the base material. By adjusting the area of the pores 3d, for example, the effective refractive index n _eff = 3.6 was set.

The photonic crystal laser 41 _{emits laser light in a direction in which the parameters r 1} and r ₂ indicating the positions of the _{lattice points 3b 1} satisfy the following equations (1) and (2).

Here, the azimuth φ is an azimuth (azimuth with reference to the X-axis direction) representing the direction of the emitted laser beam (tilted beam) projected onto a plane parallel to the AlGaInP photonic crystal layer 3 in the plane. Represents a corner).

There is a relationship of the following equation (3) between the lattice constant a, the effective refractive index n _{eff, and the wavelength λ of the emitted laser light.}

For example, from equations (1) and (2), _{it can be seen that if r 1} and r ₂ change, the inclination angle θ and the azimuth angle φ change. Therefore, as an example, r ₁ and r ₂ can form different regions, and the emission direction of the laser beam (inclination angle θ, azimuth angle φ) can be changed. It is also possible to extract the laser beam to the outside of the photonic crystal laser 41 at a desired inclination angle θ and azimuth angle φ.

A control example of the inclination angle θ will be described with reference to FIGS. 7A to 7C.

7A and 7B are schematic plan views showing an arrangement example of the n-side electrode 9 and the p-side electrode 8 in the photonic crystal laser 41, respectively. As shown in FIG. 7A, the n-side electrode 9 is formed, for example, in the shape of a window frame when viewed along the Z axis. In the example shown in FIG. 7B, the p-side electrode 8 is configured to include a plurality of p-side electrodes 8a to 8d electrically separated from each other.

When a voltage is applied between one or more of the p-side electrodes 8a to 8d and the n-side electrode 9, for example, the quantum well activity between the voltage-applied p-side electrodes 8a to 8d and the n-side electrode 9 is applied. A current is supplied to the layer 4 (quantum well active layer 4 at positions corresponding to the respective p-side electrodes 8a to 8d), and laser light is emitted from that position. The emitted laser light passes through a region (window 9a) surrounded by the window frame-shaped n-side electrode 9, and is emitted toward the outside of the photonic crystal laser 41 at an inclination angle θ and an azimuth angle φ.

In the example shown in FIG. 7B, the quantum well active layer 4 between the p-side electrodes 8a to 8d and the n-side electrode 9 (quantum well active layer 4 at a position corresponding to each p-side electrode 8a to 8d) emits light. The AlGaInP photonic crystal layer 3 (positions corresponding to the respective p-side electrodes 8a to 8d) at the position where the light is incident is designed according to the formulas (1) and (2). That is, in response to the region of the AlGaInP photonic crystal layer 3 corresponding to the p-side electrode 8 a to 8 _d, are defined r 1, _{r 2} is are prepared AlGaInP photonic crystal layer 3. As an example, the AlGaInP photonic crystal layer 3 continuously changes the inclination angle θ from the region corresponding to the p-side electrode 8a toward the region corresponding to the p-side electrode 8d. according _2), r 1, r 2 is designed to be both increases continuously.

In the example shown in FIG. 7B, the region of the AlGaInP photonic crystal layer 3 corresponding to the p-side electrode 8a is, for example, a laser beam in the direction (θ, φ) = (0 °, 0 °) (centered on the direction). R ₁ and r ₂ are defined and formed so that The regions of the AlGaInP photonic crystal layer 3 corresponding to the p-side electrodes 8b, 8c, and 8d are, for example, (θ, φ) = (10 °, 0 °), (20 °, 0 °), (30 °), respectively. , centered on (in the direction of _{0 °)) r 1, r} 2 so that the laser beam is emitted is defined, it is formed. That is, for example, when a voltage is applied only between the p-side electrode 8a and the n-side electrode 9, the photonic crystal laser 41 directs (centered in the direction) in the direction (θ, φ) = (0 °, 0 °). The laser beam is emitted. Similarly, when a voltage is applied only between the p-side electrodes 8b, 8c, 8d and the n-side electrode 9, (θ, φ) = (10 °, 0 °), respectively, from the photonic crystal laser 41. The laser beam is emitted in the directions (20 °, 0 °) and (30 °, 0 °) (centered on the direction).

For example, depending on the balance of the voltage values applied to the electrodes 8a to 8d adjacent to each other (the current value supplied to the quantum well active layer 4 at the position corresponding to the p-side electrodes 8a to 8d), the laser beam is emitted in the intermediate inclination angle θ direction. Can be emitted.

As an example, under the condition that the voltage is applied only between the electrodes 8a and 9 and between the electrodes 8b and 9, the ratio of the voltage value applied between the electrodes 8a and 9 and the voltage value applied between the electrodes 8b and 9 is set. By changing the laser beam, the laser beam can be emitted in the directions of 0 ° <θ <10 ° and φ = 0 °. In this case, if the ratio of the voltage values applied between the electrodes 8b and 9 is increased, the inclination angle θ becomes large.

Further, under the condition that the voltage is applied only between the electrodes 8b and 9 and between the electrodes 8c and 9, the ratio of the voltage value applied between the electrodes 8b and 9 and the voltage value applied between the electrodes 8c and 9 is set. By changing the laser beam, the laser beam can be emitted in the directions of 10 ° <θ <20 ° and φ = 0 °. Increasing the ratio of the voltage values applied between the electrodes 8c and 9 increases the inclination angle θ.

Similarly, the ratio of the voltage value applied between the electrodes 8c and 9 and the voltage value applied between the electrodes 8d and 9 under the condition that the voltage is applied only between the electrodes 8c and 9 and between the electrodes 8d and 9. By changing the above, it is possible to emit the laser beam in the directions of 20 ° <θ <30 ° and φ = 0 °. Increasing the ratio of the voltage values applied between the electrodes 8d and 9 increases the inclination angle θ.

In the configuration shown in FIG. 7B, the inclination angle θ can be continuously controlled in the range of 0 ° ≦ θ ≦ 30 °.

FIG. 7C is a graph showing the relationship between _{the inclination angle θ and the parameters r 1} and r ₂ when the laser beam is emitted in the emission azimuth plane having an azimuth angle φ = 0 °. The horizontal axis of the graph represents the inclination angle θ in the unit “°”, and the vertical axis represents r ₁ and r ₂ . In the case of this design, r ₁ = r ₂ . The wavelength of the laser beam was 650 nm, and the effective refractive index n _eff of the AlGaInP photonic crystal layer 3 was 3.6.

From the graph, _{it can be seen that, for example, by continuously changing r 1} and r ₂ to prepare the AlGaInP photonic crystal layer 3, the inclination angle θ can be continuously changed to emit the laser beam.

FIGS. 7A to 7C show an example in which the emission direction (inclination angle θ) of the laser light is changed in one emission directional plane where φ = 0 °, and the laser light is scanned in the uniaxial direction. To. A control example for changing the emission direction (inclination angle θ) of the laser beam in a plurality of emission directional planes will be described with reference to FIGS. 8A and 8B. In the examples shown in FIGS. 8A and 8B, the laser beam is scanned in the biaxial direction.

8A and 8B are schematic plan views showing other arrangement examples of the n-side electrode 9 and the p-side electrode 8 in the photonic crystal laser 41, respectively. FIG. 8A is the same as that of FIG. 7A, and the n-side electrode 9 is formed, for example, in the shape of a window frame when viewed along the Z axis. In the example shown in FIG. 8B, the p-side electrode 8 is configured to include a plurality of p-side electrodes 8a to 8g electrically separated from each other.

When a voltage is applied between one or more of the p-side electrodes 8a to 8g and the n-side electrode 9, for example, the quantum well activity between the voltage-applied p-side electrodes 8a to 8g and the n-side electrode 9 is applied. A current is supplied to the layer 4 (quantum well active layer 4 at a position corresponding to each p-side electrode 8a to 8g), and laser light is emitted from that position. The emitted laser light passes through a region (window 9a) surrounded by the window frame-shaped n-side electrode 9, and is emitted toward the outside of the photonic crystal laser 41 at an inclination angle θ and an azimuth angle φ.

In the example shown in FIG. 8B, the quantum well active layer 4 between each p-side electrode 8a to 8g and the n-side electrode 9 (quantum well active layer 4 at a position corresponding to each p-side electrode 8a to 8g) emits light. The AlGaInP photonic crystal layer 3 (positions corresponding to the respective p-side electrodes 8a to 8g) at the position where the light is incident is designed according to the formulas (1) and (2). That is, in response to the region of the AlGaInP photonic crystal layer 3 corresponding to the p-side electrode 8 a to 8 _g, is defined r 1, _{r 2} is are prepared AlGaInP photonic crystal layer 3. _{As an example, in the AlGaInP photonic crystal layer 3, both r 1} and r ₂ are continuous from the region corresponding to the p-side electrode 8a toward the region corresponding to the p-side electrode 8d, as in the case shown in FIG. 7B. It is designed to be large. Further, the inclination angle θ is continuously changed from the region corresponding to the p-side electrode 8a toward the region corresponding to the p-side electrode 8g at an azimuth angle φ different from that of the p-side electrodes 8a to 8d. According to the equations (1) and (2), r ₁ is designed to be continuously increased, and r ₂ is designed to be continuously decreased.

In the example shown in FIG. 8B, the region of the AlGaInP photonic crystal layer 3 corresponding to the p-side electrode 8a is, for example, a laser beam in the direction (θ, φ) = (0 °, 0 °) (centered on the direction). R ₁ and r ₂ are defined and formed so that The regions of the AlGaInP photonic crystal layer 3 corresponding to the p-side electrodes 8b, 8c, and 8d are, for example, (θ, φ) = (10 °, 0 °), (20 °, 0 °), (30 °), respectively. , centered on (in the direction of _{0 °)) r 1, r} 2 so that the laser beam is emitted is defined, it is formed. Further, the regions of the AlGaInP photonic crystal layer 3 corresponding to the p-side electrodes 8e, 8f, and 8g are, for example, (θ, φ) = (10 °, 90 °), (20 °, 90 °), (30 °), respectively. , mainly in the direction (direction of _{90 °)) r 1, r} 2 so that the laser beam is emitted is defined, is formed.

For example, when a voltage is applied only between the p-side electrode 8a and the n-side electrode 9, the photonic crystal laser 41 directs (θ, φ) = (0 °, 0 °) (centering on the direction). Laser light is emitted. Similarly, when a voltage is applied only between the p-side electrodes 8b, 8c, 8d, 8e, 8f, 8g and the n-side electrode 9, (θ, φ) = (10 °) from the photonic crystal laser, respectively. , 0 °), (20 °, 0 °), (30 °, 0 °), (10 °, 90 °), (20 °, 90 °), (30 °, 90 °) A laser beam is emitted (in the center).

For example, depending on the balance of the voltage values applied to the electrodes 8a to 8g adjacent to each other (the current value supplied to the quantum well active layer 4 at the position corresponding to the p-side electrodes 8a to 8g), the laser beam is emitted in the intermediate inclination angle θ direction. Can be emitted.

For example, the electrodes 8a to 8d arranged in the X-axis direction are the same as those described with reference to FIG. 7B.

Regarding the electrodes 8a, 8e to 8g arranged in the Y-axis direction, as an example, the voltage applied between the electrodes 8a and 9 and the voltage applied between the electrodes 8a and 9 under the condition that the voltage is applied only between the electrodes 8a and 9 and between the electrodes 8e and 9. By changing the ratio between the value and the voltage value applied between the electrodes 8e and 9, the laser beam can be emitted in the directions of 0 ° <θ <10 ° and φ = 90 °. In this case, if the ratio of the voltage values applied between the electrodes 8e and 9 is increased, the inclination angle θ becomes large.

Further, under the condition that the voltage is applied only between the electrodes 8e and 9 and between the electrodes 8f and 9, the ratio of the voltage value applied between the electrodes 8e and 9 and the voltage value applied between the electrodes 8f and 9 is set. By changing the laser beam, the laser beam can be emitted in the directions of 10 ° <θ <20 ° and φ = 90 °. Increasing the ratio of the voltage values applied between the electrodes 8f and 9 increases the inclination angle θ.

Similarly, the ratio of the voltage value applied between the electrodes 8f and 9 and the voltage value applied between the electrodes 8g and 9 under the condition that the voltage is applied only between the electrodes 8f and 9 and between the electrodes 8g and 9. By changing the above, it is possible to emit the laser beam in the directions of 20 ° <θ <30 ° and φ = 90 °. Increasing the ratio of the voltage values applied between the electrodes 8g and 9 increases the inclination angle θ.

In the configuration shown in FIG. 8B, the inclination angle θ can be continuously controlled in the range of 0 ° ≦ θ ≦ 30 ° in the two emission directional planes where φ = 0 ° and 90 °.

A control example of the inclination angle θ and the azimuth angle φ will be described with reference to FIGS. 9A and 9B.

9A and 9B are schematic plan views showing still another arrangement example of the n-side electrode 9 and the p-side electrode 8 in the photonic crystal laser 41, respectively. 9A is the same as FIG. 7A, and the n-side electrode 9 is formed, for example, in the shape of a window frame when viewed along the Z axis. In the example shown in FIG. 9B, the p-side electrode 8 is configured to include a plurality of p-side electrodes 8a, 8h to 8l that are electrically separated from each other.

When a voltage is applied between one or more of the p-side electrodes 8a, 8h to 8l and the n-side electrode 9, for example, between the p-side electrodes 8a, 8h to 8l and the n-side electrode 9 to which the voltage is applied. A current is supplied to the quantum well active layer 4 (quantum well active layer 4 at positions corresponding to the respective p-side electrodes 8a and 8h to 18l), and laser light is emitted from that position. The emitted laser light passes through a region (window 9a) surrounded by the window frame-shaped n-side electrode 9, and is emitted toward the outside of the photonic crystal laser 41 at an inclination angle θ and an azimuth angle φ.

In the example shown in FIG. 9B, the quantum well active layer 4 between each p-side electrode 8a, 8h to 8l and the n-side electrode 9 (quantum well active layer at a position corresponding to each p-side electrode 8a, 8h to 8l). The AlGaInP photonic crystal layer 3 (positions corresponding to the respective p-side electrodes 8a and 8h to 8l) at the position where the light emitted in 4) is incident is designed according to the formulas (1) and (2). That is, each p-side electrode 8a, corresponding to the region of the AlGaInP photonic crystal layer 3 corresponding to _8H～8l, defined r 1, _{r 2} is are prepared AlGaInP photonic crystal layer 3.

_{As an example, in the AlGaInP photonic crystal layer 3, both r 1} and r ₂ are continuous from the region corresponding to the p-side electrode 8a toward the region corresponding to the p-side electrode 8i, as in the case shown in FIG. 8B. It is made to be large. _{Further, r 1} is continuously increased and r ₂ is continuously decreased from the region corresponding to the p-side electrode 8a toward the region corresponding to the p-side electrode 8k. Furthermore, the region of AlGaInP photonic crystal layer 3 corresponding to the p-side electrode 8l, rather than the region corresponding to the p-side electrode _8j, r 1, _{r 2} are both large and from the region corresponding to the p-side electrode 8h However, r ₁ is made large and r ₂ is made small.

In the example shown in FIG. 9B, the region of the AlGaInP photonic crystal layer 3 corresponding to the p-side electrode 8a is, for example, a laser beam in the direction (θ, φ) = (0 °, 0 °) (centered on the direction). R ₁ and r ₂ are defined and formed so that Further, the regions of the AlGaInP photonic crystal layer 3 corresponding to the p-side electrodes 8h and 8i are oriented in the directions (θ, φ) = (15 °, 0 °) and (30 °, 0 °), respectively. _{R 1} and r ₂ are defined and formed so that the laser beam is emitted (at the center). Further, the regions of the AlGaInP photonic crystal layer 3 corresponding to the p-side electrodes 8j and 8k are oriented in the directions (θ, φ) = (15 °, 90 °) and (30 °, 90 °), respectively. _{R 1} and r ₂ are defined and formed so that the laser beam is emitted (at the center). Further, in the region of the AlGaInP photonic crystal layer 3 corresponding to the p-side electrode 8l, for example, the laser beam is emitted in the direction (θ, φ) = (15 °, 45 °) (centering on the direction). r ₁ and r ₂ are defined and formed.

For example, when a voltage is applied only between the p-side electrode 8a and the n-side electrode 9, the photonic crystal laser 41 directs (θ, φ) = (0 °, 0 °) (centering on the direction). Laser light is emitted. Similarly, when a voltage is applied only between the p-side electrodes 8h, 8i, 8j, 8k, 8l and the n-side electrode 9, (θ, φ) = (15 °,) from the photonic crystal laser 41, respectively. Laser light is emitted in the directions (0 °), (30 °, 0 °), (15 °, 90 °), (30 °, 90 °), (15 °, 45 °) (centered on the direction). ..

For example, depending on the balance of the voltage values applied to the electrodes 8a and 8h to 8l (the current values supplied to the quantum well active layer 4 at the positions corresponding to the p-side electrodes 8a and 8h to 8l), the intermediate inclination angle θ and the azimuth angle φ It is possible to emit laser light in the direction.

For example, the electrodes 8a, 8h, and 8i arranged in the X-axis direction are the same as those described for the electrodes 8a to 8d with reference to FIG. 7B. Further, for example, the electrodes 8a, 8j, and 8k arranged in the Y-axis direction are the same as those described for the electrodes 8a, 8e to 8g with reference to FIG. 8B. Also in the configuration shown in FIG. 9B, similarly to the configuration shown in FIG. 8B, the inclination angles are continuously in the range of 0 ° ≤ θ ≤ 30 ° in the two emission directional planes where φ = 0 ° and 90 °. θ can be controlled.

Further, in the configuration shown in FIG. 9B, the voltage value applied between the electrodes 8h and 9 and the voltage value between the electrodes 8l and 9 are applied under the condition that the voltage is applied only between the electrodes 8h and 9 and between the electrodes 8l and 9. By changing the ratio with the voltage value applied to, the laser beam can be emitted in the directions of θ = 15 ° and 0 ° <φ <45 °.

Further, for example, the ratio of the voltage value applied between the electrodes 8l and 9 and the voltage value applied between the electrodes 8j and 9 under the condition that the voltage is applied only between the electrodes 8l and 9 and between the electrodes 8j and 9. By changing the above, the laser beam can be emitted in the directions of θ = 15 ° and 45 ° <φ <90 °.

As described above, in the configuration shown in FIG. 9B, the laser beam can be emitted in such a manner as to rotate the emission directional plane.

Further, in the configuration shown in FIG. 9B, for example, the voltage value applied to the electrodes 8a, 8h, 8l, 8j (the current value supplied to the quantum well active layer 4 at the position corresponding to the p-side electrodes 8a, 8h, 8l, 8j). ), It is possible to emit the laser beam in the direction in which the inclination angle θ is 0 ° ≦ θ ≦ 15 ° and the azimuth angle φ is 0 ° ≦ φ ≦ 90 °.

Although three configuration examples have been described with reference to FIGS. 7A to 9B, the configurations are not limited to these, and the ranges of the inclination angle θ and the azimuth angle φ can be arbitrarily set.

In FIGS. 7A to 9B, the number of electrodes is reduced for ease of understanding, but it is preferable to use more electrodes in order to improve the accuracy of the intermediate angle.

Although the photonic crystal laser 41 that emits red light has been described with reference to FIGS. 6A to 9B, the same applies to the photonic crystal lasers 42 and 43 that emit green light and blue light. The n-type GaN photonic crystal layers 12 and 22 of the photonic crystal lasers 42 and 43 (see FIGS. 1B and 1C) are also configured as shown in FIGS. 6A to 6D, for example. _{The effective refractive indexes n eff} of the n-type GaN photonic crystal layers 12 and 22 can be, for example, 2.4 and 2.5, respectively. In the photonic crystal lasers 42 and 43, for example, green and blue laser lights having wavelengths of 560 nm and 450 nm are emitted, and the parameters r ₁ and r ₂ are emitted in directions satisfying the equations (1) and (2), respectively. Also in the photonic crystal lasers 42 and 43, there _{is a relationship of the equation (3) between the lattice constant a, the effective refractive index n eff} , and the wavelength λ of the emitted laser light.

Also in the photonic crystal lasers 42 and 43, for example _{, n-type GaN photonic crystal layers 12 and 22 having regions in which r 1} and r ₂ are different are formed, and the laser beam is extracted at a desired inclination angle θ and azimuth angle φ. Is done. The p-side electrodes 18, 28, and n-side electrodes 19 and 29 of the photonic crystal lasers 42 and 43 can have the same configuration as the p-side electrodes 8a to 8l and n-side electrodes 9 of the photonic crystal laser 41. The regions of the n-type GaN photonic crystal layers 12 and 22 corresponding to the p-side electrodes 18 and 28 are, for example, (θ, φ) = (0 °, 0 °), (10) according to the equations (1) and (2). °, 0 °), (20 °, centered on the direction (direction of 0 °), etc.) the laser beam defines a r _1, r ₂ as emitted, are formed. The inclination angle θ and the azimuth angle φ can be controlled in the same manner as in the case of the photonic crystal laser 41 (see FIGS. 7A to 9B).

10A and 10B show the relationship between _{the inclination angle θ and the parameters r 1} and r _{2 when} the photonic crystal lasers 42 and 43 emit laser light in the emission azimuth plane having an azimuth angle φ = 0 °, respectively. It is a graph and corresponds to FIG. 7C showing the photonic crystal laser 41. In both FIGS. 10A and 10B, the horizontal axis of the graph represents the inclination angle θ in the unit “°”, and the vertical axis represents r ₁ and r ₂ . Further, the relationship when _{r 1} = r _{2 is shown.} The wavelengths of the laser beam are 560 nm (FIG. 10A) and 450 nm (FIG. 10B), and the effective refractive indexes n _eff of the n-type GaN photonic crystal layers 12 and 22 are 2.4 (FIG. 10A) and 2.5 (FIG. 10B). ).

From the graph, even in the photonic crystal laser 43, for example, by continuously changing the _{r 1} and _{r 2} to produce the n-type GaN photonic crystal layers 12 and 22, continuously change the tilt angle θ It can be seen that the laser beam can be emitted.

FIG. 11A is a schematic view showing a basic configuration of a lighting device (vehicle headlight) according to an embodiment. The vehicle headlight according to the embodiment is, for example, an automobile headlight, and includes a photonic crystal laser 30 and a first control device 60.

The photonic crystal laser 30 includes, for example, chip-shaped photonic crystal lasers 41, 42, 43. As described above, the chip-shaped photonic crystal lasers 41, 42, and 43 emit red (R), green (G), and blue (B) laser beams α and β in a plurality of directions, specifically, arbitrarily. It can be emitted at an inclination angle θ (θ ≦ 45 °) and an azimuth angle φ.

The first control device 60 controls the emission of laser light from the photonic crystal laser 30 (41, 42, 43).

The laser beam emitted from the photonic crystal laser 30 forms an automobile headlight illumination pattern in front of the vehicle as illumination light.

FIG. 11B is a schematic view showing the photonic crystal laser 30. The photonic crystal laser 30 includes, for example, a red light emitting unit 30R, a green light emitting unit 30G, and a blue light emitting unit 30B which are regularly and alternately arranged along the X-axis direction and the Y-axis direction.

The red light emitting unit 30R is formed by a single chip-shaped photonic crystal laser 41 or by arranging a plurality of photonic crystal lasers 41 in a block shape as an example. Similarly, in the green light emitting unit 30G and the blue light emitting unit 30B, a single chip-shaped photonic crystal lasers 42 and 43, or a plurality of photonic crystal lasers 42 and 43 are arranged in a block shape as an example. It is formed.

As shown in FIG. 11C, for example, the red light α, the green light α, and the blue light α emitted from the red, green, and blue light emitting units 30R, 30G, and 30B are superposed with beam spots (irradiated to the same region). ) Form white light. The same applies to the red light β, green light β, and blue light β emitted from the red, green, and blue light emitting units 30R, 30G, and 30B. Even in the emission direction control of the laser beams α and β, the red light, the green light, and the blue light are maintained in a superposed state, for example.

See FIG. 12A. The vehicle headlight according to the embodiment may further include a beam shaping diffraction element 31, a second control device 63, a sensing device 64, and the like.

FIG. 12B is a schematic perspective view showing the beam shaping diffraction element 31. In this figure, each of the red, green, and blue light emitting units 30R, 30G, and 30B (see FIG. 11B), which are two-dimensionally repeatedly arranged, is provided by a single chip-shaped photonic crystal lasers 41, 42, and 43, respectively. The case where it is formed is shown.

The beam shaping diffraction element 31 is arranged in close contact with the laser light emitting surface side of, for example, the red, green, and blue light emitting portions 30R, 30G, and 30B (chip-shaped photonic crystal lasers 41, 42, 43). Further, for example, a two-dimensional beam shaping diffraction pattern corresponding to each of the chip-shaped photonic crystal lasers 41, 42, and 43 that are repeatedly arranged two-dimensionally is provided. The beam shaping diffraction element 31 is a beam (red light, green light, blue light) emitted from each of the red, green, and blue light emitting units 30R, 30G, and 30B (chip-shaped photonic crystal lasers 41, 42, 43). It has the function of maintaining the emission direction of the light and aligning its shape and size.

Although the transmittance of the laser beam is reduced, the beam shaping diffraction element 31 can be provided with a light scattering function. The light transmittance is about 85% with the holographic beam shaping diffuser.

Again, see FIG. 12A.

In the second control device 63, for example, light distribution control software is used.

The sensing device 64 is, for example, a camera, a radar, or the like.

The first control device 60 includes, for example, a laser drive circuit 61 and a beam scanning calculation circuit 62.

As an example, the sensing device 64 senses the front of the vehicle and obtains vehicle peripheral information such as a pedestrian, an oncoming vehicle, a preceding vehicle, and an obstacle. It also includes a light distribution monitor camera that monitors the light distribution (illumination light). The obtained sensing information is input to the light distribution control software of the second control device 63. The light distribution control software determines, for example, the optimum light distribution (illumination light) pattern based on the input sensing information and the like.

The light distribution control software dynamically controls an arbitrary light distribution by a rewritable program. By rewriting the program of the light distribution control software, one lighting device, for example, a vehicle headlight according to an embodiment can be used for various lighting purposes.

Information on the light distribution pattern (shape of the light distribution pattern, brightness distribution, etc.) determined by the light distribution control software of the second control device 63 is output to the first control device 60.

The first control device 60 controls the emission of the laser light from the photonic crystal laser 30 based on the information of the light distribution pattern input from the second control device 63. Specifically, for example, for each of the chip-shaped photonic crystal lasers 41, 42, and 43, the inclination angle θ, the rotation angle of the emission azimuth surface Ps, the laser light output, the blinking frequency, the pulse width, the simultaneous emission, and the like are controlled. .. Equal control may be performed for all chip photonic crystal lasers 41, 42, 43, or equal control may be performed for some of the plurality of chip photonic crystal lasers 41, 42, 43. ..

The inclination angle θ can be controlled in the same manner as described with reference to FIGS. 7A to 9B, for example. The rotation angle of the exit directional plane Ps can be controlled in the same manner as described with reference to FIGS. 9A and 9B, for example. The laser beam output is determined by the magnitude of the voltage value (current value supplied to the quantum well active layer 4 (13, 23)) applied between the electrodes 8 (18, 28) and 9 (19, 29) and the applied voltage waveform ( It can be controlled by the high or low duty ratio of the supply current waveform). The blinking frequency can be controlled by the number of times the applied voltage (supply current) is turned on and off. The pulse width can be controlled by the length of the on period of the applied voltage (supply current). Simultaneous emission is realized, for example, in the case of red light by simultaneously applying a voltage between a plurality of the p-side electrodes 8a to 8l and the n-side electrode 9, and has been described, for example, with reference to FIG. The effect etc. can be obtained. The number of laser beams emitted from one chip-shaped photonic crystal laser 41 can be controlled by the number of p-side electrodes 8a to 8l to which a voltage is applied. Simultaneous emission control of green light and blue light can be performed in the same manner.

The beam scanning calculation circuit 62 calculates, for example, the inclination angle θ, the rotation angle of the exit azimuth surface Ps, the laser light output, the blinking frequency, the pulse width, and the like of the laser light (RGB twin beam) that realizes the optimum light distribution pattern. Ask. The laser drive circuit 61 emits laser light (RGB twin beam) from the photonic crystal laser 30 with the obtained inclination angle θ, the rotation angle of the emission azimuth surface Ps, the laser light output, the blinking frequency, the pulse width, and the like. The emitted red, green, and blue laser beams are superimposed and projected in front of the vehicle to form an automobile headlight illumination pattern.

The formed automobile headlight illumination pattern is confirmed by, for example, the light distribution monitor camera of the sensing device 64, and feedback is applied so as to match the light distribution pattern determined by the second control device 63.

For example, the information obtained by the sensing device 64 is sequentially updated. The second control device 63 repeats at predetermined time intervals, determines, for example, an optimum light distribution pattern based on the updated information, and outputs the determined optimum light distribution pattern information to the first control device 60. ..

See FIG. 12C. The vehicle headlight shown in FIG. 12A includes one photonic crystal laser module (in FIG. 12A, red, green, and blue light emitting units 30R, 30G, 30B, a beam shaping diffraction element 31, and a laser drive circuit 61. However, as shown in FIG. 12C, a configuration including a plurality of photonic crystal laser modules may be provided.

The beam scanning calculation circuit 62 is based on the information of the light distribution pattern input from the second control device 63, for example, the inclination angle θ of the laser beam (RGB twin beam) that realizes the optimum light distribution pattern, and the emission azimuth surface Ps. Calculate the rotation angle, laser light output, blinking frequency, pulse width, etc. The obtained result is output to the laser drive circuit 61 of each photonic crystal laser module, and each photo is obtained with the obtained tilt angle θ, the rotation angle of the exit azimuth surface Ps, the laser light output, the blinking frequency, the pulse width, and the like. Laser light (RGB twin beam) is emitted from the nick crystal laser module. The emitted laser light (RGB twin beam) forms an automobile headlight illumination pattern in front of the vehicle.

In the configuration shown in FIG. 12C, even when the output of each photonic crystal laser module is low, the desired light distribution can be realized by synthesizing the laser light emitted from a plurality of photonic crystal laser modules. it can. Further, for example, fail-safe against a defect of the photonic crystal laser module is achieved. Furthermore, in addition to the normal ADB function, it is possible to support various light distribution controls such as independent lighting for a plurality of objects and lighting avoiding concealed objects.

In the lighting device according to the embodiment, photonic crystal lasers 30 (chip-shaped photonic crystal lasers 41, 42, 43) having a structure and a control function different from those of a normal laser oscillator are used as a laser light source. In the lighting device according to the embodiment, the beam control functions of the photonic crystal lasers 41, 42, and 43 (tilt angle θ control, emission azimuth surface Ps rotation angle control, laser light output control, blinking frequency control, pulse width control, simultaneous It is possible to form a desired automobile headlight illumination pattern (for example, the optimum light distribution pattern determined by the second control device 63) by utilizing the emission control and the like). Dynamic headlight distribution is realized by superimposing red light, green light, and blue light emitted from the photonic crystal lasers 41, 42, and 43 (software light distribution control). In addition, the lighting pattern can be changed in various ways. The illumination pattern may include information such as characters and figures.

For example, unlike simple raster scanning control, smooth light distribution (brightness steps due to discrete lighting control and brightness discontinuities (brightness discontinuities) even in the formation of light-dark boundaries tilted from the horizontal and vertical directions and a predetermined brightness distribution (discrete lighting control). Smooth light distribution) without dark lines) can be realized. Also, the resolution does not depend on the hardware of the light source, for example in a lighting system using an LED (light emitting diode) array.

Further, in the lighting device according to the embodiment, the beam emitting characteristics of the photonic crystal lasers 41, 42, and 43 are utilized, and for example, a projection lens that requires space is unnecessary. Therefore, the lighting system can be a semiconductor package level size lighting system. Therefore, there is a high degree of freedom in installation such as the number of installations and the installation location.

Further, the lighting device according to the embodiment can be manufactured with the same equipment as the equipment for manufacturing the semiconductor light emitting element. Therefore, the accuracy and reliability of the lighting device can be improved, and the manufacturing cost can be reduced.

Further, when the illumination device is configured by using the photonic crystal lasers 41, 42, and 43, the emission control of the laser light can be performed by, for example, controlling the mode of applying the voltage to the electrodes. Since a MEMS mirror or polygon mirror having a mechanically movable part is not used, for example, a compact, lightweight, high light distribution accuracy, high reliability, and long life lighting device can be obtained. In addition, it is possible to perform various controls as compared with an irradiation device using a MEMS mirror, a polygon mirror, or the like.

As described above, the illuminating device according to the embodiment is a high-quality illuminating device.

It should be noted that, for example, instead of scanning the entire automobile headlight illumination pattern (laser light irradiation by the photonic crystal laser 30), non-scanning type illumination (illumination having a fixed light distribution including a conventional illumination device). ) May be used to scan only the part that requires dynamic light distribution control. Further, it is also possible to share the irradiation of the high-luminance region in the central portion of the illumination range with the illumination of the fixed light distribution.

Further, a laser light source that emits light in a wavelength region for sensing (for example, near infrared rays) may be added to the photonic crystal laser 30. It can perform independent control for sensing and include functions as a TOF (time of flight) sensor and a light source of LIDAR (laser imaging detection and ranging).

See FIG. The configuration of the lighting device according to the embodiment can be applied to, for example, a street light. It is possible to use a street light that has a display function on the irradiation surface (road surface) instead of a street light that only performs ordinary street lighting. For example, when it snows, lane lines, pedestrian crossings, warnings, etc. are displayed to provide information to pedestrians, vehicles, etc. It may have a function such as illuminating a specific object.

Although the present invention has been described above with reference to Examples and the like, the present invention is not limited thereto.

For example, in the embodiment, the beam shaping diffraction element 31 is arranged in close contact with the laser beam emitting surface side of the chip-shaped photonic crystal lasers 41, 42, 43, but instead of the beam shaping diffraction element 31, a cover glass or a beam A diffuser having no shaping function may be used.

Further, in the embodiment, the configuration in which white light is obtained by mixing red light, green light, and blue light (superimposition in the irradiation region) is shown, but if the configuration uses laser light of a plurality of colors, this is used. Not limited. The chromaticity can be controlled by independent control of the photonic crystal lasers 41, 42, and 43, and the chromaticity is not limited to this. For example, a desired illumination color can be obtained by mixing laser beams of a plurality of colors. it can. A first photonic crystal laser that emits a laser beam of the first color and a second photonic crystal laser that emits a laser beam of a second color different from the first color may be used.

Further, although it was mentioned that a plurality of chip-shaped photonic crystal lasers 41, 42, and 43 are arranged in a block shape to form red, green, and blue light emitting portions 30R, 30G, and 30B, they are arranged in a line shape. It may be configured.

It should be noted that, as in the embodiment, the photonic crystal lasers 30 are not configured by using the same number of photonic crystal lasers 41, 42, 43, but the outputs and lighting devices of the photonic crystal lasers 41, 42, 43 are used. Photonic crystal lasers 41, 42, and 43 can be used in a number and ratio required for synthesizing illumination colors, depending on the intended use.

Further, in the embodiment, for example, laser beams of a plurality of colors were obtained by using different materials for forming the photonic crystal lasers 41, 42, and 43, but the second harmonic generation (SHG) and the like were generated. It may be used to obtain laser beams of a plurality of colors. Further, instead of the green photonic crystal laser 42, the second harmonic generation of the infrared wavelength having the InGaAs / GaAs quantum well active layer may be used.

In addition, it will be obvious to those skilled in the art that various changes, improvements, combinations, etc. are possible.

The lighting device having a dynamic light distribution control function (including an information presentation function) according to the embodiment can be suitably used as, for example, a vehicle lighting device, for example, an automobile headlight. Further, it can be suitably used not only for vehicle lamps but also for various lighting fixtures and the like.

Automotive headlights have a characteristic light distribution with extreme light and dark regions and potentially require dynamic light distribution control. For example, in the embodiment, a lighting device used as a headlight for an automobile has been described, but the lighting device dynamically controls an arbitrary light distribution by a rewritable program. Therefore, the lighting device according to the embodiment can be said to be a programmable lighting device that can be used for various lighting purposes including general lighting and for displaying information by characters, figures, etc. by rewriting the program.

1 n-type GaAs substrate 2 n-type AlGaInP clad layer 3 AlGaInP photonic crystal layer 3a Optical resonance state forming lattice 3a ₁ lattice point 3b light emission lattice 3b ₁ lattice point 3c lattice 3c ₁ lattice point 3d vacancies 4 GaInP / AlGaInP Quantum well active layer 5 AlGaInP guide layer 6 p-type AlGaInP clad layer 7 p-type GaAs contact layer 8, 8a to 8 l p-side electrode 9 n-side electrode 9a window 10 n-type GaN substrate 11 n-type AlGaN clad layer 12 n-type GaN photo Nick crystal layer 13 InGaN / InGaN quantum well active layer 14 GaN layer 15 p-type AlGaN electron block layer 16 p-type AlGaN clad layer 17 p-type GaN contact layer 18, 18a to 18d p-side electrode 19 n-side electrode 20 n-type GaN substrate 21 n-type AlGaN clad layer 22 n-type GaN photonic crystal layer 23 InGaN / GaN quantum well active layer 24 GaN layer 25 p-type AlGaN electron block layer 26 p-type AlGaN clad layer 27 p-type GaN contact layers 28, 28a to 28d p Side electrode 29 n Side electrode 30 Photonic crystal laser 30R Red light emission unit 30G Green light emission unit 30B Blue light emission unit 31 Beam shaping diffraction elements 41, 42, 43 Photonic crystal laser 60 First controller 61 Laser drive circuit 62 Beam scanning calculation circuit 63 Second controller 64 Sensing device

Claims (9)

A first photonic crystal laser that y de laser light of a first color,
A second photonic crystal laser that morphism exiting the laser light of the second color different from the first color,
Have a first and a controller for controlling emission of laser light from the first photonic crystal laser and said second photonic crystal laser,
The first photonic crystal laser and the second photonic crystal laser have a photonic crystal layer in which a photonic crystal structure for forming an optical resonance state and a photonic crystal structure for emitting light are formed.
Each of the first photonic crystal laser and the second photonic crystal laser has a plurality of electrodes electrically separated from each other, and a plurality of regions of the photonic crystal layer corresponding to the plurality of electrodes. Is specified so that the laser beam is emitted in a predetermined direction, respectively.
By controlling the balance of the voltages applied to the plurality of electrodes, the first control device controls the inclination angle θ and the emission azimuth plane of the laser light from the first photonic crystal laser and the second photonic crystal laser. By changing the rotation angle φ of Ps,
The laser beam is a vehicle headlight that scans in an elliptical region . Further, it is arranged on the laser beam emitting surface side of the first and second photonic crystal lasers, maintains the emission direction of the laser beam emitted from the first and second photonic crystal lasers, and has the same shape and size. The vehicle headlight according to claim 1, further comprising a diffraction element. The vehicle headlight according to any one of claims 1 to 2 , wherein the first control device controls the output of laser light emitted from the first and second photonic crystal lasers. The vehicle headlight according to any one of claims 1 to 3 , wherein the first control device controls a blinking frequency of a laser beam emitted from the first and second photonic crystal lasers. The vehicle headlight according to any one of claims 1 to 4 , wherein the first control device controls a pulse width of a laser beam emitted from the first and second photonic crystal lasers. The vehicle headlight according to any one of claims 1 to 5 , wherein the first control device controls the number of laser beams emitted from the first and second photonic crystal lasers. Further, it includes a second control device that determines a light distribution pattern based on sensing information.
The first control device controls the emission of laser light from the first and second photonic crystal lasers based on the information of the light distribution pattern determined by the second control device according to claims 1 to 6 . The vehicle headlight according to any one of the items. The vehicle headlight according to claim 7 , wherein in the second control device, light distribution control software that dynamically controls an arbitrary light distribution by a rewritable program is used. The first control device is
Controlling the output of the striking laser beam that irradiates the central portion of the elliptical region so as to be larger than the output of the laser beam that irradiates the left and right regions.
Alternatively, the frequency of the striking laser beam that irradiates the central portion of the elliptical region is controlled to be smaller than the frequency of the laser beam that irradiates the left and right regions.
The vehicle headlight according to any one of claims 1 to 8, wherein one of the above is performed.

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