Illumination and distance measuring devices

Abstract

Provided is, for example, an illumination device having improved uniform irradiation characteristics.　This illumination device comprises: a light-emitting element that has a plurality of first light-emitting units and a plurality of second light-emitting units; a first optical member that substantially collimates and outputs a plurality of first light beams output from the plurality of first light-emitting units and a plurality of second light beams output from the plurality of second light-emitting units; a second optical member that shapes a beam shape of the plurality of first light beams and / or the plurality of second light beams and outputs the plurality of first light beams and the plurality of second light beams as light beams having mutually differing beam shapes; and a third optical member. The third optical member is disposed on the optical paths of the plurality of first light beams and the plurality of second light beams, wherein the third optical member acts on the plurality of first light beams and on the plurality of second light beams differently.

Description

[Technical Field]

[0001] The present technology relates to an illumination device and a distance measuring device. [Background technology]

[0002] Illumination devices that irradiate an object with a light beam are used for applications such as measuring distances using time of flight (ToF) or structured light, and recognizing the shape of an object. Some distance measuring devices use illumination devices that use, for example, vertical cavity surface-emitting lasers (VCSELs) as light-emitting elements, and some devices include such illumination devices. One method for measuring a wide range of short distances using the ToF method is to diffuse light emitted from multiple light-emitting elements using a diffuser plate, uniformly irradiate the entire measurement area (hereinafter also referred to as uniform irradiation), and detect the light using a photodetector with two-dimensionally divided light-receiving elements. One method for extending the distance measurement distance is to collimate the light emitted from multiple light-emitting elements using a collimator lens and irradiate the measurement object with a point-like light beam (hereinafter also referred to as spot irradiation). Another method has been proposed for achieving spot irradiation and uniform irradiation by shifting the entire focus of the spot light (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2019 / 0018137 Summary of the Invention [Problem to be solved by the invention]

[0004] In this field, it is desirable to improve the uniformity of the uniform illumination without reducing the light intensity of the spot illumination.

[0005] An object of the present technology is to provide an illumination device that improves the uniformity of uniform illumination without reducing the light intensity of spot illumination, and a distance measuring device that includes the illumination device. [Means for solving the problem]

[0006] This technology is a light emitting element having a plurality of first light emitting portions and a plurality of second light emitting portions; a first optical member that outputs the plurality of first light beams emitted from the plurality of first light-emitting units and the plurality of second light beams emitted from the plurality of second light-emitting units in substantially parallel form; a second optical member that shapes the beam shape of at least one of the plurality of first light beams and the plurality of second light beams and emits the plurality of first light beams and the plurality of second light beams as light beams having beam shapes different from each other; The third optical element Equipped with The third optical member is disposed on the optical paths of the plurality of first light beams and the plurality of second light beams, and the third optical member has different effects on the plurality of first light beams and the plurality of second light beams. the law of nature, the third optical member does not act on the plurality of first light beams, but refracts or diffracts the plurality of second light beams in a predetermined direction; the plurality of first light beams emitted from the plurality of first light-emitting units are light beams that are irradiated onto an irradiation object in the form of spots that are independent from each other; The plurality of second light beams emitted from the plurality of second light-emitting units are light beams that are irradiated approximately uniformly over a predetermined range on an irradiation target by a portion of the second light beams superimposed on the second light beams emitted from adjacent second light-emitting units. It is a lighting device.

[0007] This technology is The lighting device described above; a control unit that controls the lighting device; a light receiving unit that receives light reflected from an object to be irradiated; a distance measuring unit that calculates the distance from the image data obtained by the light receiving unit; have It is a distance measuring device. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic cross-sectional view of a lighting device according to an embodiment. [Figure 2]FIG. 2 is a block diagram showing an example of a schematic configuration of a distance measuring device equipped with an illumination device. [Figure 3] FIG. 3 is a diagram showing an irradiation pattern when the lighting device is performing spot irradiation. [Figure 4] FIG. 4 is a diagram showing an irradiation pattern when the lighting device is irradiating uniformly. [Figure 5] FIG. 5 is a diagram showing an irradiation pattern when spot irradiation and uniform irradiation are performed simultaneously. [Figure 6] FIG. 6 is a cross-sectional view illustrating an example of a light-emitting device according to an embodiment. [Figure 7] FIG. 7 is a diagram illustrating an example of the configuration of a light-emitting unit according to an embodiment. [Figure 8] FIG. 8 is an enlarged view of the configuration of the light-emitting unit in one embodiment. [Figure 9] 9A is a schematic plan view illustrating an example of the configuration of the microlens array of FIG. 1, and FIG. 9B is a schematic view illustrating an example of the cross-sectional configuration of the microlens array of FIG. [Figure 10] Figure 10A is a schematic diagram showing the position of a light-emitting unit for uniform irradiation relative to the microlens array shown in Figure 9A, and Figure 10B is a schematic diagram showing the position of a light-emitting unit for spot irradiation relative to the microlens array shown in Figure 9A. [Figure 11] FIG. 11 is a diagram illustrating the beam forming function in one embodiment. [Figure 12] FIG. 12 is a diagram illustrating an irradiation pattern for an object in one embodiment. [Figure 13] FIG. 13 is a schematic diagram illustrating an example of a diffraction element. [Figure 14] FIG. 14 is a schematic diagram showing the pattern of a light beam that has passed through a diffraction element. [Figure 15] 15A and 15B are schematic cross-sectional views of a diffraction element according to one embodiment. [Figure 16] 16A and 16B are schematic diagrams showing a liquid crystal element that can be used in place of a diffraction element. [Figure 17]17A and 17B are schematic diagrams showing metamaterials that can be used in place of diffraction elements. [Figure 18] FIG. 18 is a diagram illustrating an example of the configuration of a drive circuit of a lighting device. [Figure 19] FIG. 19 is a diagram illustrating another example of the configuration of a driving circuit for a lighting device. [Figure 20] FIG. 20 is a diagram illustrating the light emission sequence of the lighting device. [Figure 21] FIG. 21 is a diagram showing a first example of grouping of light emitting elements in a modified example. [Figure 22] FIG. 22 is a diagram showing a second example of grouping of light emitting elements in the modified example. [Figure 23] FIG. 23 is a diagram showing a third example of grouping of light emitting elements in a modified example. [Figure 24] FIG. 24 is a diagram showing a fourth example of grouping of light emitting elements in the modified example. [Figure 25] FIG. 25 is a diagram showing an example of a top view of a semiconductor laser driving device in an application example. [Figure 26] FIG. 26 is a diagram showing an example of a cross section of a semiconductor laser driving device in an application example. [Figure 27] FIG. 27 is a diagram showing another example of a cross-sectional view of the semiconductor laser driving device in the application example. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present technology will be described with reference to the drawings. The description will be made in the following order. <1. One embodiment> <2. Modifications> <3. Application Examples>

[0010] <1. One embodiment> Fig. 1 is a cross-sectional view schematically illustrating an example of a schematic configuration of an illumination device (illumination device 1) according to an embodiment of the present technology. Fig. 2 is a block diagram illustrating a schematic configuration of a distance measuring device (distance measuring device 100) including the illumination device 1 illustrated in Fig. 1. The distance measuring device 100 includes the illumination device 1, a control unit 220 that controls the illumination device 1, a light receiving unit 210 that receives light reflected from an object to be measured, and a distance measuring unit 230 that calculates a distance from image data obtained by the light receiving unit 210.

[0011] The distance measuring device 100 employs, for example, a ToF (Time of Flight) method or a Structured Light method. The ToF method is a method for calculating distance from the time it takes for a light beam emitted from the distance measuring device to be reflected by an object to be measured and return to the distance measuring device. The Structured Light method is a method for calculating distance from the distortion of the pattern of a light beam emitted from the distance measuring device to an object to be measured and returned to the distance measuring device.

[0012] An illumination device 1 according to one embodiment emits light from a plurality of light-emitting units (light-emitting units 110 (first light-emitting unit) and 120 (second light-emitting unit); see FIG. 7). A diffraction element 14, which will be described later, is an optical element that tiled light L1 and expanded the illumination range to light L2, and is capable of expanding the illumination range by tiling 3x3. Lights L110 and L120 perform, for example, spot illumination as shown in FIG. 3, uniform illumination as shown in FIG. 4, and simultaneous illumination as shown in FIG. 5.

[0013] [Lighting equipment configuration] The lighting device 1 includes, for example, a light-emitting element 11, a microlens array 12 (an example of a second optical member), a collimator lens 13 (an example of a first optical member), a diffraction element 14, a diffraction element 34, and a quarter-wave plate 35.

[0014] The microlens array 12, collimator lens 13, diffraction element 14, diffraction element 34, and quarter-wave plate 35 are arranged, for example, in this order, on the optical path of light (light L1, L2) emitted from the light-emitting element 11. The light-emitting element 11 and the microlens array 12 are held, for example, by a holder 21, and the collimator lens 13 and diffraction element 14 are held, for example, by a holder 22. The holder 21 has, for example, one anode electrode unit 23 and two cathode electrode units 24, 25 on a surface 21S2 opposite to a surface 21S1 that holds the light-emitting element 11 and the microlens array 12. Each of the components that make up the lighting device 1 will be described in detail below.

[0015] (About light-emitting elements) The light-emitting element 11 is, for example, a surface-emitting surface-emitting semiconductor laser. Fig. 6 is a schematic diagram showing an example of a cross-sectional configuration of the light-emitting section (light-emitting sections 110, 120) of the light-emitting element 11. Although two light-emitting sections (light-emitting sections 110, 120) are shown in Fig. 6, the number of light-emitting sections may be at least two. Unless otherwise specified, the description of the light-emitting section 110 can also be applied to the light-emitting section 120.

[0016] The light-emitting element 11 generally comprises an n-type substrate 130 having a main surface 130A and a main surface 130B opposite to the main surface 130A, a lower electrode 152 provided on the main surface 130A of the n-type substrate 130, a p-type DBR layer 145 provided on the main surface 130B side of the n-type substrate 130 and having a main surface 145A, and at least two light-emitting sections (e.g., light-emitting sections 110, 120) provided on the side of the p-type DBR layer 145 opposite the main surface 145A.

[0017] A tunnel junction layer 160 is provided between the principal surface 130B of the n-type substrate and the principal surface 145A of the p-type DBR layer 145. Note that "between" simply means that the layer is provided between them, and does not necessarily have to be in contact with them. Note that "on the side" simply means that the layer is present in that direction, and does not necessarily have to be in contact with them. The light-emitting section 110 is stacked on the p-type DBR layer 145 and includes an n-type DBR layer 141 having a principal surface 141A and a principal surface 141B opposite to the principal surface 141A, and an upper electrode 151 (an example of a second electrode) provided on the principal surface 141B side of the n-type DBR layer 141. The light-emitting element 11 also has a cathode electrode lead-out portion divided into at least two regions. For example, the upper electrode 151 of the light-emitting section 110 is connected to an electrode pad 240, and the upper electrode 151 of the light-emitting section 120 is connected to an electrode pad 250.

[0018] More specifically, an n-type buffer layer 161 is provided between the major surface 130A of the n-type substrate 130 and the tunnel junction layer 160. The light-emitting section 110 has a configuration in which a p-type spacer layer 144, an active layer 143, an n-type spacer layer 142, an n-type buffer layer 149, a current constriction layer 148, an n-type DBR layer 141, and an n-type contact layer 146 are stacked in this order from the side opposite to the major surface 145A of the p-type DBR layer 145, and these components (hereinafter also referred to as semiconductor layers as appropriate) form a columnar mesa section 147. An upper electrode 151 is attached to the n-type contact layer 146. Each component of the light-emitting element 11 will be described in detail below.

[0019] The n-type substrate 130 is, for example, an n-type GaAs substrate. Examples of n-type impurities include silicon (Si) and selenium (Se). The semiconductor layers are each made of, for example, an AlGaAs-based compound semiconductor. An AlGaAs-based compound semiconductor refers to a compound semiconductor that contains at least aluminum (Al) and gallium (Ga) from the group 13 elements in the periodic table, and at least arsenic (As) from the group 15 elements in the periodic table.

[0020] The n-type DBR layer 141 is formed by alternately stacking a low refractive index layer and a high refractive index layer (both not shown). The low refractive index layer is, for example, n-type Al with a thickness of λ0 / 4n1 (λ0 is the emission wavelength, n1 is the refractive index). x1 Ga 1-x1 As (0 < x1 < 1). The high refractive index layer is, for example, n-type Al with a thickness of λ0 / 4n2 (n2 is the refractive index). x2 Ga 1-x2 As (0 < x2 < x1).

[0021] The n-type spacer layer 142 is composed of, for example, n-type Al x3 Ga 1-x3 As (0 < x3 < 1). The p-type spacer layer 144 is composed of, for example, p-type Al x5 Ga 1-x5 As (0 < x5 < 1). Examples of p-type impurities include zinc (Zn), magnesium (Mg), and beryllium (Be).

[0022] The active layer 143 has a multi-quantum well structure (Multi Quantum well, MQW). The active layer 143 is, for example, composed of a structure in which a thin film of n-type Al x6 Ga 1-x6 As (0 < x6 < 1) and a tunnel junction layer are alternately stacked.

[0023] The p-type DBR layer 145 is formed by alternately stacking a low refractive index layer and a high refractive index layer (both not shown). The low refractive index layer is, for example, p-type Al with a thickness of λ0 / 4n3 (n3 is the refractive index). x8 Ga 1-x8 As (0 < x8 < 1). The high refractive index layer is, for example, p-type Al with a thickness of λ0 / 4n4 (n4 is the refractive index). x9 Ga 1-x9 As (0 < x9 < x8). The contact layer 16 is composed of, for example, p-type Al x10 Ga 1-x10 As (x10 < 1).

[0024] The current confinement layer 148 and the n-type buffer layer 149 are provided, for example, in the n-type DBR layer 141. The current confinement layer 148 is formed at a position away from the active layer 143 in relation to the n-type buffer layer 149. The current confinement layer 148 is provided, for example, in the n-type DBR layer 141 in place of a low refractive index layer, for example, several layers away from the active layer 143. The current confinement layer 148 has a current injection region 148A and a current confinement region 148B. The current injection region 148A is formed in a central region within the plane. The current confinement region 148B is formed on the periphery of the current injection region 148A, i.e., in the outer edge region of the current confinement layer 148, and has an annular shape.

[0025] The current injection region 148A is, for example, n-type Al x11 Ga 1-x11 The current confinement region 148B is made of, for example, aluminum oxide (Al2O3), for example, n-type Al x11 Ga 1-x11 It is obtained by oxidizing an oxidizable layer (not shown) made of As from the side surface of the mesa portion 147. As a result, the current confinement layer 148 has the function of confining the current.

[0026] The n-type buffer layer 149 is formed closer to the active layer 143 in relation to the current confinement layer 148. The n-type buffer layer 149 is formed adjacent to the current confinement layer 148. For example, as shown in FIG. 6, the n-type buffer layer 149 is formed in contact with the surface (lower surface) of the current confinement layer 148 facing the active layer 143. Note that a thin layer having a thickness of, for example, several nanometers may be provided between the current confinement layer 148 and the n-type buffer layer 149. The n-type buffer layer 149 is provided, for example, in the n-type DBR layer 141 in place of a high refractive index layer at a location several layers away from the current confinement layer 148.

[0027] The n-type buffer layer 149 has an unoxidized region and an oxidized region (both not shown). The unoxidized region is mainly formed in the central region in the plane, for example, at a site contacting the current injection region 148A. The oxidized region is formed at the periphery of the unoxidized region and has an annular shape. The oxidized region is mainly formed in the outer edge region in the plane, for example, at a site contacting the current constriction region 148B. The oxidized region is formed biased toward the current constriction layer 148 in a portion other than the portion corresponding to the outer edge of the n-type buffer layer 149.

[0028] The unoxidized region is composed of a semiconductor material containing Al, for example, n-type Al x12 Ga 1-x12 As (0.85 < x12 ≦ 0.98) or n-type In a Al x13 Ga 1-x13-a As (0.85 < x13 ≦ 0.98). The oxidized region is composed of, for example, aluminum oxide (Al2O3) and is obtained by oxidizing a oxidized layer (not shown) composed of, for example, n-type Al x12 Ga 1-x12 As or n-type In b Al x13 Ga 1-x13-b As from the side surface side and the oxidized layer side of the mesa portion 147. The oxidized layer of this n-type buffer layer 149 is composed of a material and thickness such that the oxidation rate is faster than that of the p-type DBR layer 145 and the n-type DBR layer 141, and slower than that of the oxidized layer of the current constriction layer 148.

[0029] The tunnel junction layer 160 is a substance through which a tunnel current flows in this section when energized, for example, n-type and p-type Al doped at a high concentration x14 Ga 1-x14It is composed of a thin film of As(0 < x14 < 1). The tunnel junction layer 160 can be any material as long as a tunnel current can flow through it, as exemplified above. An n-type buffer layer 161 is provided between the tunnel junction layer 160 and the n-type substrate 130. As the n-type buffer layer, the same type as the n-type buffer layer 149 can be applied.

[0030] On the upper surface of the mesa portion 147 (the upper surface of the n-type contact layer 146), an annular upper electrode 151 having an opening (light emitting port 151A) is formed at least in the region facing the current injection region 148A. Also, an insulating layer (not shown) is formed on the side surface and the peripheral surface of the mesa portion 147. The upper electrode 151 is connected to the electrode pad 240 or the electrode pad 250 by wiring (not shown) for each of the light emitting unit groups X1 to X9 and the light emitting unit groups Y1 to Y9, respectively (see FIG. 7). For example, the electrode pad 240 or the electrode pad 250 is electrically connected by wire bonding. Also, a lower electrode 152 is provided on the other surface of the n-type substrate 130. The lower electrode 152 is electrically connected to, for example, the anode electrode portion 23. Thus, one embodiment is an embodiment in which the anode electrode portion is used as a common electrode and the cathode electrode portions are provided separately.

[0031] Here, the upper electrode 151 is formed by laminating titanium (Ti), platinum (Pt), and gold (Au) in this order, and is electrically connected to the n-type contact layer 146 above the mesa portion 147. The lower electrode 152 has a structure in which an alloy of gold (Au) and germanium (Ge), nickel (Ni), and gold (Au) are laminated in this order from the n-type substrate 130 side, and is electrically connected to the n-type substrate 130.

[0032] (Regarding the light emitting unit) The plurality of light-emitting units have a configuration in which, for example, a plurality of light-emitting units used for spot irradiation (a plurality of light-emitting units 110 for spot irradiation) and a plurality of light-emitting units used for uniform irradiation (a plurality of light-emitting units 120 for uniform irradiation) are arranged in an array on an n-type substrate 130. The plurality of light-emitting units 110 and the plurality of light-emitting units 120 are electrically isolated from each other. In this embodiment, the polarization direction of the laser beam L110 emitted from the plurality of light-emitting units 110 is different from the polarization direction of the laser beam L120 emitted from the plurality of light-emitting units 120.

[0033] While the light-emitting element 11 described above has two mesa portions 147, the distance measuring device 100 has a plurality of light-emitting units, for example, a plurality of light-emitting units 110 and a plurality of light-emitting units 120. The plurality of light-emitting units 110 and the plurality of light-emitting units 120 are electrically connected to each other. Specifically, as shown in FIG. 7, the plurality of light-emitting units 110 form a plurality of (e.g., nine in FIG. 7) light-emitting unit groups X (light-emitting unit groups X1 to X9) each consisting of n (e.g., 12 in FIG. 7) light-emitting units 110 extending in one direction (e.g., the Y-axis direction). Similarly, the plurality of light-emitting units 120 form a plurality of (e.g., nine in FIG. 7) light-emitting unit groups Y (light-emitting unit groups Y1 to Y9) each consisting of m (e.g., 12 in FIG. 7) light-emitting units 120 extending in one direction (e.g., the Y-axis direction). The light-emitting unit groups X1-X9 and light-emitting unit groups Y1-Y9 are alternately arranged on a rectangular n-type substrate 130, as shown in FIG. 7 . The light-emitting unit groups X1-X9 are electrically connected to electrode pads 240 provided along one side of the n-type substrate 130, and the light-emitting unit groups Y1-Y9 are electrically connected to electrode pads 250 provided along the other side of the n-type substrate 130 opposite the one side. While FIG. 7 illustrates an example in which the light-emitting unit groups X1-X9 and Y1-Y9 are alternately arranged, this is not limiting. For example, the number of light-emitting units 110 and the number of light-emitting units 120 can be arbitrarily arranged depending on the desired number, positions, and amount of light output of the light-emitting points. As an example, the light-emitting units 120 may be arranged every two rows of the light-emitting units 110.

[0034] 8 is an enlarged view of a portion of the arrangement of the plurality of light-emitting units 110 and the plurality of light-emitting units 120 shown in FIG. 7. The plurality of light-emitting units 110 and the plurality of light-emitting units 120 preferably have different light-emitting areas (OA diameters W3 and W4). Specifically, the light-emitting area (OA diameter W3) of the plurality of light-emitting units 110 for spot irradiation is preferably smaller than the light-emitting area (OA diameter W4) of the plurality of light-emitting units 120 for uniform irradiation. This allows the light beams for spot irradiation (laser beams L110 (first light) irradiated onto the irradiation object 1000 in the form of spots independent of each other, see FIG. 12) irradiated from the plurality of light-emitting units 110 to be more finely focused, thereby enabling irradiation of the object with a smaller spot. Furthermore, the light beam for uniform irradiation irradiated from the plurality of light-emitting units 120 (laser beam L120 (second light) that is superimposed with light emitted from adjacent light-emitting units 120 and irradiates the irradiation object 1000 approximately uniformly over a predetermined range, see FIG. 12) can irradiate a wider range, enabling more uniform and high-power uniform irradiation of the irradiation object 1000. Accordingly, the opening width W1 of the wiring connecting each of the plurality of light-emitting units 110 is smaller than the opening width W2 of the wiring connecting each of the plurality of light-emitting units 120. The number of light-emitting units for spot irradiation and the number of light-emitting units for uniform irradiation are the same, but may be different. Furthermore, the FFP (Far Field Pattern) may be different between the light-emitting units for spot irradiation and the light-emitting units for uniform irradiation.

[0035] (Microlens arrays, collimator lenses, and diffraction elements) The microlens array 12 shapes and emits at least one of the beams (laser beam L110, laser beam L120) emitted from, for example, the plurality of light-emitting units 110 for spot irradiation and the plurality of light-emitting units 120 for uniform irradiation. Fig. 9A is a schematic diagram showing an example of the planar configuration of the microlens array 12, and Fig. 9B is a schematic diagram showing the cross-sectional configuration of the microlens array 12 taken along line II shown in Fig. 9A. The microlens array 12 has a plurality of microlenses arranged in an array, and includes a plurality of lens portions 12A and a parallel plate portion 12B.

[0036] In one embodiment, the microlens array 12 is arranged so that the lens portion 12A faces the plurality of light-emitting units 120 for uniform irradiation as shown in Fig. 10A, and so that the parallel plate portion 12B faces the plurality of light-emitting units 110 for spot irradiation as shown in Fig. 10B. As a result, as shown in Fig. 11, the laser beams L120 emitted from the plurality of light-emitting units 120 are refracted by the lens surfaces of the lens portion 12A to form, for example, a virtual light-emitting point P2' within the microlens array 12. That is, the light-emitting points P2 of the plurality of light-emitting units 120, which were at the same height as the light-emitting points P1 of the plurality of light-emitting units 110, are shifted in the optical axis direction (e.g., the Z-axis direction) of the light (laser beams L110, L120) emitted from the plurality of light-emitting units 110 and the plurality of light-emitting units 120.

[0037] Therefore, by switching the light emission of the multiple light-emitting units 110 and the multiple light-emitting units 120, the laser beams L110 emitted from the multiple light-emitting units 110 pass directly through the microlens array 12 and form spot-shaped irradiation patterns such as those shown in FIGS. 3 and 12. Furthermore, the laser beams L120 emitted from the multiple light-emitting units 120 are refracted by the microlens array 12 and partially overlap with the laser beams L120 emitted from adjacent light-emitting units 120, as shown in FIGS. 4 and 12, thereby forming an irradiation pattern that irradiates a predetermined range with approximately uniform light intensity. In the lighting device 1, by switching the light emission of the multiple light-emitting units 110 and the light emission of the multiple light-emitting units 120, it is possible to switch between spot irradiation and uniform irradiation.

[0038] 11 shows an example in which the microlens array 12 functions as a relay lens, but the present invention is not limited to this. For example, the virtual light-emitting points P2′ of the plurality of light-emitting units 120 may be formed between the light-emitting units 120 and the microlens array 12.

[0039] The collimator lens 13 outputs the laser beams L110 emitted from the plurality of light-emitting units 110 and the laser beams L120 emitted from the plurality of light-emitting units 120 as substantially parallel light. The collimator lens 13 is a lens for collimating the laser beams L110 and L120 emitted from the microlens array 12, for example, and combining them with the diffraction element 14.

[0040] The diffraction element 14 splits and emits each of the laser beams L110 emitted from the plurality of light-emitting units 110 and the laser beams L120 emitted from the plurality of light-emitting units 120. As the diffraction element 14, for example, a diffractive optical element (DOE) that splits the laser beams L110 emitted from the plurality of light-emitting units 110 and the laser beams L120 emitted from the plurality of light-emitting units 120 into 3 x 3 beams can be used. By disposing the diffraction element 14, it is possible to tile the respective light beams of the laser beams L110 and L120, thereby increasing the number of spots during spot irradiation or expanding the irradiation range during uniform irradiation, for example.

[0041] (Regarding the holding part) The holders 21 and 22 are used to hold the light emitting element 11, the microlens array 12, the collimator lens 13, and the diffraction element 14. Specifically, the holder 21 holds the light emitting element 11 in a recess C provided on the upper surface (surface 21S1) and holds the microlens array 12 along the surface 21S1. The holder 22 holds the collimator lens 13 and the diffraction element 14. The microlens array 12, the collimator lens 13, and the diffraction element 14 are held by the holders 21 and 22, respectively, by, for example, an adhesive. The holders 21 and 22 are connected to each other so that light L1 (specifically, laser beam L110) and light L2 (specifically, laser beam L120) emitted from the light emitting element 11 are incident on predetermined positions of the microlens array 12, and so that the light L1 and L2 transmitted through the collimator lens 13 become approximately parallel light.

[0042] A plurality of electrode portions are provided on the rear surface (surface 21S2) of the holder 21. Specifically, an anode electrode portion 23 common to the plurality of light-emitting portions 110 for spot irradiation and the plurality of light-emitting portions 120 for uniform irradiation, a cathode electrode portion 24 of the plurality of light-emitting portions 110 for spot irradiation, and a cathode electrode portion 25 of the plurality of light-emitting portions 120 for uniform irradiation are provided on the surface 21S2 of the holder 21.

[0043] The configuration of the plurality of electrode units provided on the surface 21S2 of the holder 21 is not limited to the above. For example, the anode electrode units of the plurality of light-emitting units 110 for spot irradiation and the plurality of light-emitting units 120 for uniform irradiation may be formed separately, or the anode electrode units of the plurality of light-emitting units 110 for spot irradiation and the plurality of light-emitting units 120 for uniform irradiation may be formed as a common electrode unit. While FIG. 1 shows an example in which the microlens array 12 is held by the holder 21, this is not limiting, and the microlens array 12 may be held by the holder 22, for example. The collimator lens 13 and the diffraction element 14 may also be held by the holder 21.

[0044] (Regarding the third optical element) FIG. 13 shows the shape of the diffraction element 34 in one embodiment. In one embodiment, the diffraction element 34 diffracts (or refracts) the light beam emitted from the light-emitting unit for uniform irradiation to increase the number of light beams. For example, as shown by the thin dotted and solid circles in FIG. 14, one light beam can be divided into five. In contrast, the light beam emitted from the light-emitting unit for spot irradiation is not diffracted by the diffraction element 34, and is not divided. Instead, the light beam is irradiated as is, as shown by the thick dotted circles in FIG. 14. Due to the action of the diffraction element 34, the light beam for uniform irradiation is superimposed with adjacent light beams, increasing the overlapping range of adjacent light beams, and more uniform light is irradiated. The light beam for spot irradiation is irradiated while maintaining high light intensity without reducing the light intensity of each individual beam.

[0045] 15A and 15B show cross-sectional views of a diffraction element 34 according to one embodiment. The diffraction element 34 in FIGS. 15A and 15B has a three-layer structure in which a first layer 171, a second layer 172, and a third layer 173 are bonded together in this order. The refractive index of the first layer 171 is n1, and the refractive index of the third layer 173 is n3. The refractive index of the second layer 172 varies depending on the direction. The refractive index in the Y direction shown in FIG. 15A is n2y, and the refractive index in the X direction shown in FIG. 8B is n2x. The diffraction element 34 having a three-layer structure is formed by stacking anisotropic materials, where n1 and n2x are the same (n1=n2x), but n1 and n2y are different (n1≠n2y). Each layer can be made of any material as long as these refractive index relationships are satisfied.

[0046] As described above, the diffraction element 34 has different refractive indices in the X and Y directions, and therefore acts as a parallel plate for light polarized in a certain direction (X direction), and as a diffraction element that diffracts (refracts) the light beam for light polarized in a direction perpendicular to the certain direction (Y direction). Thus, the diffraction element 34 is a polarizing diffraction element that refracts or diffracts a light beam traveling in a predetermined direction (specific direction), and can change the polarization characteristics of the light beam emitted from the uniformly irradiated light-emitting unit. A volume hologram may be used instead of the diffraction element 34. The diffraction element 34 may also be a device that refracts light, such as a Fresnel lens.

[0047] The diffraction element 34 diffracts or refracts the laser beam L120 emitted from the light-emitting unit for uniform irradiation, but has no effect on the laser beam L110 emitted from the light-emitting unit for spot irradiation, allowing it to pass through as is. That is, the diffraction element 34 acts differently on the laser beam L110 and the laser beam L120. This allows distance measurement without reducing the intensity of the light beam emitted from the light-emitting unit for spot irradiation. Note that the positions of the diffraction element 14 and the diffraction element 34 described above may be reversed, or an optical diffracting surface may be positioned on both sides of a single optical element or on one side of a single optical surface. When superimposed, the function of the diffraction grating 14 is the same regardless of the polarization direction of the light.

[0048] Furthermore, a quarter-wave plate 35 is disposed on the diffraction element 34. The quarter-wave plate 35 causes the light beam irradiated onto the object to be measured to become circularly polarized, thereby suppressing changes in the reflection characteristics of the object to be measured due to its material and orientation. Note that the diffraction element 34 and the quarter-wave plate 35 may both be formed on a single optical element.

[0049] (Another example of the third optical member) Another example of the third optical member will now be described. Instead of the diffraction element 34 described above, an organic liquid crystal element 175 having different orientations in the X and Y directions, as shown schematically in FIGS. 16A and 16B, can be used. In this case, the polarization direction of the beam light can be changed by switching the light emission of the VCSEL, so there is no need to switch the orientation of the organic liquid crystal element 175 to change the polarization direction of the beam light. This eliminates the need for a circuit configuration or flexible cable for switching the orientation of the organic liquid crystal element 175, and also eliminates the problem of the time required to switch the orientation of the organic liquid crystal element 175. An inorganic liquid crystal element may be used instead of the organic liquid crystal element 175. Inorganic liquid crystal elements have better temperature characteristics and heat resistance than organic liquid crystal elements, and can be used in applications requiring high reliability, such as automotive applications.

[0050] Instead of the diffraction element 34, a so-called metamaterial 176 having a microstructure on a scale equal to or smaller than the wavelength of the light beam, as shown schematically in FIGS. 17A and 17B, can be used. FIG. 17B is an enlarged view of a portion of the metamaterial 176 shown in FIG. 17A. The metamaterial 176 can generate diffraction characteristics that vary depending on the polarization direction. The use of the metamaterial 176 allows the polarization to be changed along with the diffraction direction, and the metamaterial 176 can also have the function of the quarter-wave plate 35 (e.g., the function of converting circularly polarized light into linearly polarized light). In other words, the configuration related to the quarter-wave plate 35 can be eliminated, resulting in a smaller device and reduced costs. Furthermore, the function of the collimator lens 13 may also be realized by a metamaterial, and the collimator lens 13, diffraction element 34, and quarter-wave plate 35 may all be formed in a single optical element.

[0051] [Lighting device driving method] 18 shows an example of the configuration of a drive circuit of the lighting device 1. As shown in the figure, the anodes of the first light-emitting unit group 181 and the second light-emitting unit group 182 are connected to a power supply (VCC). The cathode of the first light-emitting unit group 181 is connected to a drive unit 265, and the cathode of the second light-emitting unit group 182 is connected to a drive unit 266. The first light-emitting unit group 181 is, for example, a group of light-emitting units 110 connected to an electrode pad 240. The second light-emitting unit group 182 is, for example, a group of light-emitting units 120 connected to an electrode pad 250. For example, switching between the light-emitting unit groups can be achieved by outputting modulation signals from two drive units and using an external selector switch.

[0052] An n-type MOSFET (Metal Oxide Semiconductor Field Effect Transistor) can be used as the driving unit 265 and the driving unit 266. When a modulation signal that defines the timing of ON / OFF modulation is supplied to each of the driving units 265 and 266, the driving unit 265 and the driving unit 266 connects the ground to the first group of light-emitting units 181 or the second group of light-emitting units 182 at the ON timing. As a result, a current flows through the first group of light-emitting units 181 and the second group of light-emitting units 182 at the ON timing, causing light to be emitted. The cathodes of the first group of light-emitting units 181 and the second group of light-emitting units 182 are completely separated and are provided with the driving unit 265 and the driving unit 266, respectively, so that the first group of light-emitting units 181 and the second group of light-emitting units 182 can be driven with different waveforms (timing and current).

[0053] Each of the driving units 265 and 266 may be a P-type MOSFET or a bipolar transistor.

[0054] The driving units 265 and 266 may be provided, for example, outside the lighting device 1, or may be built into the holding unit 21. The light-emitting elements 11 may be directly connected to the driving units. In the example shown in FIG. 18, a common anode electrode is used, but as shown in FIG. 19, a circuit configuration in which a common cathode electrode is used may also be used. In the circuit configuration shown in FIG. 19, switching between the first light-emitting unit group 181 and the second light-emitting unit group 182 is performed, for example, by using a single driving unit 270 and complementarily turning on / off external switches SW1 and SW2.

[0055] FIG. 20 shows an example of the light emission sequence of the lighting device 1. The period during which one distance measurement image is generated is called a "frame," and one frame is set to a time of, for example, 33.3 msec (frequency 30 Hz). For example, a rectangular continuous wave of 100 MHz·Duty=50% is used as the distance measurement pulse, which is emitted continuously during the accumulation period. Multiple accumulation periods with different conditions can be set within a frame. Although FIG. 20 shows eight accumulation periods, this number is not limited.

[0056] As shown in the figure, in the illumination device 1, the first light-emitting unit group 181 emits light in one frame, and the light-receiving unit 210 (see FIG. 2) receives the reflected light to generate a distance measurement image. In the next frame, the second light-emitting unit group 182 emits light, and the light-receiving unit 210 receives the reflected light to generate a distance measurement image. Note that while FIG. 20 shows the first light-emitting unit group 181 and the second light-emitting unit group 182 switching every frame, they may also be switched every several frames. Note that the switching of the light emission of the first light-emitting unit group 181 and the second light-emitting unit group 182 may be performed, for example, on a frame-by-frame basis, on a block-by-block basis, or on a multiple-block basis. This enables faster switching between spot illumination and uniform illumination than, for example, a method of mechanically switching the focal positions of laser beams emitted from multiple light-emitting units.

[0057] According to this embodiment, the third optical member diffracts or refracts the light beam emitted from the light-emitting unit for uniform irradiation, thereby increasing the overlapping range of the uniform irradiation pattern. This improves the accuracy of distance measurement. Furthermore, by making the third optical member have no effect on the light beam emitted from the light-emitting unit for spot irradiation, distance measurement can be performed without reducing the intensity of the light beam emitted from the light-emitting unit for spot irradiation.

[0058] <2. Modifications> Although the embodiments of the present disclosure have been specifically described above, the contents of the present disclosure are not limited to the above-described embodiments, and various modifications based on the technical concepts of the present disclosure are possible. Each of the multiple modifications will be described below. Note that the same reference numerals will be used to designate the same or similar components as those in the first embodiment, and redundant description will be omitted as appropriate.

[0059] The microlens array 12 described in the embodiment may be omitted. In this case, for example, the laser beam L110 emitted from the light-emitting unit 110 is light for spot irradiation that passes directly through the diffraction element 14, etc., and the laser beam L120 emitted from the light-emitting unit 120 is light for spot irradiation that is diffracted by the diffraction element 14, etc., and the number of spots in the laser beam L120 is increased. The laser beam L110 has a high light intensity, which enables long-distance distance measurement, and the laser beam L120 has a large number of spots, which has the advantage of providing relatively high resolution in distance measurement.

[0060] The light emitting elements 11 in one embodiment may be divided into groups. Figures 21 to 23 are diagrams showing examples of grouping the light emitting elements 11 in application examples of the present technology.

[0061] In the example shown in Fig. 21, it is assumed that one region is formed for every several columns (two columns in this example) and switching is performed for each region. In the example shown in Fig. 22, it is assumed that one frame is further divided vertically into two to form rectangular regions and switching is performed for each region. In the example shown in Fig. 23, it is assumed that the number of divisions in the vertical direction is three and switching is performed for each region.

[0062] Increasing the number of spots and maintaining the light intensity per spot increases power consumption and may even exceed eye safety standards. However, switching the light emission in units of illuminated areas allows for flexible adjustment. Light emission can be switched for each frame, or for blocks within a frame. It is also possible to recognize the position of the object to be measured and illuminate that area.

[0063] 24 is a diagram showing another example of grouping of light-emitting elements 11 in a modified example of the present technology. This example shows an example of grouping two columns at a time so that each column is staggered. For example, the first and third columns form region A1, the second and fourth columns form region A2, the fifth and seventh columns form region A3, the sixth and eighth columns form region A4, the ninth and eleventh columns form region A5, and the tenth and twelfth columns form region A6. This allows for controlled switching of light emission every two columns. This allows for multipath countermeasures while reducing power consumption through region switching and achieving high optical output within laser safety standards.

[0064] <3. Application Examples> Next, an application example will be described. In this application example, the present technology is configured as a semiconductor laser driving device 300. FIG. 25 is a diagram showing an example of a top view of the semiconductor laser driving device 300 in the application example. The semiconductor laser driving device 300 is designed to measure distance using ToF. ToF has the feature of high depth accuracy, although not as high as structured light, and can operate without problems even in dark environments. In addition, it is thought to have many advantages over other methods such as structured light and stereo cameras in terms of simplicity of device configuration, cost, etc.

[0065] In the semiconductor laser driving device 300, the semiconductor laser 301, the photodiode 420, and the passive components 430 are mounted on the surface of a substrate 400 that incorporates a laser driver 500 (an example of a driving element) and are electrically connected by wire bonding. The substrate 400 is assumed to be a printed wiring board. Here, the above-mentioned lighting devices 1 and 1B can be applied to the semiconductor laser 301, and the light receiving unit 210 in FIG. 1, for example, can be applied to the photodiode.

[0066] The semiconductor laser 301 is a semiconductor device that emits laser light by passing a current through a PN junction of a compound semiconductor. Examples of the compound semiconductor that can be used here include aluminum gallium arsenide (AlGaAs), indium gallium arsenide phosphide (InGaAsP), aluminum gallium indium phosphide (AlGaInP), and gallium nitride (GaN).

[0067] The laser driver 500 is a driver integrated circuit (IC) for driving the semiconductor laser 301. The laser driver 500 is built into the substrate 400 in a face-up state. For the electrical connection with the semiconductor laser 301, it is necessary to reduce wiring inductance, so it is desirable to make the wiring length as short as possible.

[0068] The photodiode 420 is a diode for detecting light, and is used for APC (Automatic Power Control) to monitor the light intensity of the semiconductor laser 301 and maintain the output of the semiconductor laser 301 constant.

[0069] The passive components 430 are circuit components other than active elements such as capacitors and resistors, and include a decoupling capacitor for driving the semiconductor laser 301.

[0070] 26 is a diagram showing an example of a cross section of a semiconductor laser driving device 300 in an application example of the present technology. As described above, the substrate 400 has the laser driver 500 built in, and the semiconductor laser 301 and the like mounted on its surface. The connection between the semiconductor laser 301 and the laser driver 500 on the substrate 400 is made through a connection via 401. By using the connection via 401, it is possible to shorten the wiring length.

[0071] The semiconductor laser 301 is assumed to be a vertical-cavity surface-emitting laser (VCSEL). The VCSEL has a substrate 310 as a substrate material, and a common anode provided underneath. The light-emitting points are formed as trapezoidal mesas, each including a light-emitting element 341.

[0072] The anode electrode of the light-emitting element 341 is connected to the signal line pattern 406 on the substrate 400 via a connection layer. The cathode electrodes of the light-emitting element are connected to the metal layers 330A and 330B, and one end of the driver elements 501A and 501B is connected to the metal layers 330A and 330B via wire bonding 410A and 410B. Here, the connection layer can be formed of either silver paste or solder. The wire bonding 410A and 410B are connected to the driver elements 510A and 510B by connection vias 411A and 411B.

[0073] In addition, in the application example, the light emitting point of the semiconductor laser 301 is located immediately above the substrate 400, so that the heat generated at the light emitting point can be efficiently dissipated to the component-embedded substrate.

[0074] The board 400 also includes thermal vias for heat dissipation. Each component mounted on the board 400 is a heat source, and by using thermal vias, the heat generated in each component can be dissipated from the rear surface of the board 400.

[0075] 26, in the application example, a capacitor 409 is mounted on a substrate 400 as a decoupling capacitor and is connected between a pattern 406 and a ground (GND) 408. By providing the capacitor 409 as a decoupling capacitor, the charge stored in the capacitor 409 can be used as a drive current for the semiconductor laser 301. Thus, according to the application example, when modulating the laser at high speed, the charge stored in the capacitor 409 mounted in close proximity to the semiconductor laser 301 becomes the drive current for the semiconductor laser 301, thereby realizing even higher speed modulation.

[0076] As shown in FIG. 27, the light emitting element 341 may be installed upside down. In this case, the emitted light 309 from the light emitting element 341 is emitted through the substrate 310. The cathode of the light emitting element 341 is connected to a signal line pattern 406 on the substrate 400 via bumps 349A and 349B, and is connected to one end of driver elements 501A and 501B of a laser driver 500 built into the substrate 400 via connection vias 411A and 411B. The other ends of the driver elements 501A and 501B are connected to a ground (GND) 408. A metal layer 330 is provided on the surface of the substrate 310 on the light emitting point side, and is connected to a power supply pattern 407 of the substrate 400 via wire bonding 410. Here, the metal layer 330 may be a transparent electrode such as ITO (Indium Tin Oxide). The non-light-emitting side of the light-emitting element 341 is connected to the driver elements 501A and 501B via bumps 349A and 349B, patterns 406A and 406B, and connection vias 411A and 411B. Here, the bumps 349A and 349B may be made of gold (Au), copper (Cu), or solder.

[0077] Note that the above-described embodiment shows an example for realizing the present technology, and the matters in the embodiment and the matters specifying the invention in the claims correspond to each other. Similarly, the matters specifying the invention in the claims and the matters in the embodiment of the present technology having the same name correspond to each other. However, the present technology is not limited to the embodiment, and can be realized by applying various modifications to the embodiment within the scope of the gist thereof.

[0078] The effects described in this specification are merely examples and are not limiting, and other effects may also be obtained.

[0079] The present technology can also be configured as follows. (1) a light emitting element having a plurality of first light emitting portions and a plurality of second light emitting portions; a first optical member that outputs the plurality of first light beams emitted from the plurality of first light-emitting units and the plurality of second light beams emitted from the plurality of second light-emitting units in a substantially parallel manner; a second optical member that shapes the beam shape of at least one of the plurality of first light beams and the plurality of second light beams and emits the plurality of first light beams and the plurality of second light beams as light beams having beam shapes different from each other; The third optical element Equipped with The third optical member is disposed on the optical paths of the plurality of first light beams and the plurality of second light beams, and the action of the third optical member on the plurality of first light beams is different from the action of the third optical member on the plurality of second light beams. Lighting equipment. (2) The third optical member does not act on the plurality of first light beams, but refracts or diffracts the plurality of second light beams in a predetermined direction. The lighting device according to (1). (3) the plurality of first light beams emitted from the plurality of first light-emitting units are light beams that are irradiated onto an irradiation object in the form of spots that are independent from each other, The plurality of second light beams emitted from the plurality of second light-emitting units are light beams that are irradiated approximately uniformly over a predetermined range on an irradiation target by a portion of the second light beams superimposed on second light beams emitted from adjacent second light-emitting units. The lighting device according to (1) or (2). (4) The third optical member is an optical member that increases an overlapping range in which parts of the second light beams overlap with each other. (3) The lighting device according to (3). (5) The plurality of first light beams emitted from the plurality of first light-emitting units and the plurality of second light beams emitted from the plurality of second light-emitting units have different polarization characteristics. A lighting device according to any one of (1) to (4). (6) The third optical member is a polarizing diffraction element. A lighting device according to any one of (1) to (5). (7) The third optical member is a liquid crystal element. A lighting device according to any one of (1) to (6). (8) The third optical member is a metamaterial. A lighting device according to any one of (1) to (7). (9) The lighting device according to any one of (1) to (8), a control unit that controls the lighting device; a light receiving unit that receives light reflected from an object to be irradiated; a distance measuring unit that calculates a distance from image data obtained by the light receiving unit; have Ranging device. [Explanation of symbols]

[0080] 1···Illumination device, 11···Light emitting element, 12···Microlens array, 13···Collimator lens, 34···Diffraction element, 35···1 / 4 wavelength plate, 110, 120···Light emitting unit, 210···Light receiving unit, 220···Control unit, 230···Distance measuring unit, 1000···Irradiation object, L110, L120···Laser beam

Claims

1. a light emitting element having a plurality of first light emitting portions and a plurality of second light emitting portions; a first optical member that outputs the plurality of first light beams emitted from the plurality of first light-emitting units and the plurality of second light beams emitted from the plurality of second light-emitting units in substantially parallel beams; a second optical member that shapes a beam shape of at least one of the plurality of first light beams and the plurality of second light beams and emits the plurality of first light beams and the plurality of second light beams as light beams having beam shapes different from each other; a third optical member; Equipped with the third optical member is disposed on optical paths of the plurality of first light beams and the plurality of second light beams, and an action of the third optical member on the plurality of first light beams is different from an action of the third optical member on the plurality of second light beams; the third optical member does not act on the plurality of first light beams, but refracts or diffracts the plurality of second light beams in a predetermined direction; the plurality of first light beams emitted from the plurality of first light-emitting units are light beams that are irradiated onto an irradiation object in the form of spots that are independent from each other, The plurality of second light beams emitted from the plurality of second light-emitting units are light beams that are irradiated approximately uniformly over a predetermined range on an irradiation target by a portion of the second light beams superimposed on second light beams emitted from adjacent second light-emitting units. Lighting equipment.

2. The third optical member is an optical member that increases an overlapping range in which parts of the second light beams overlap with each other. The lighting device according to claim 1 .

3. The plurality of first light beams emitted from the plurality of first light-emitting units and the plurality of second light beams emitted from the plurality of second light-emitting units have different polarization characteristics. The lighting device according to claim 1 .

4. The third optical member is a polarizing diffraction element. The lighting device according to claim 1 .

5. The third optical member is a liquid crystal element. The lighting device according to claim 1 .

6. The third optical member is a metamaterial. The lighting device according to claim 1 .

7. The lighting device according to claim 1 ; a control unit that controls the lighting device; a light receiving unit that receives light reflected from an object to be irradiated; a distance measuring unit that calculates a distance from image data obtained by the light receiving unit; have Ranging device.

Images