Light emitting device and measuring device

Abstract

To reduce the size of a light emission device in comparison to a case where an electrode unit is arranged in the longitudinal direction of the light emission device.SOLUTION: A light emission device comprises: a substrate; a light emission unit which is made of a plurality of light emission elements; a transfer unit which outputs a signal with which the light emission states of the light emission elements sequentially propagate; and electrode units for inputting / outputting signals for driving the transfer unit. The substrate is in a rectangular shape having the long sides and the short sides and the electrode units are arranged along the short sides of the substrate with the transfer unit held therebetween. The electrode units each have a transfer signal electrode applied with a transfer signal for transferring the light emission states of the light emission elements in the control order, and a power source electrode which applies a power source potential and a reference potential to the transfer unit. The transfer signal electrodes and the power source electrodes are arranged in plurality on the same straight line with respect to the transfer unit.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a light emitting device and a measurement device. [Background technology]

[0002] A light-emitting element array is known in which a large number of light-emitting elements whose threshold voltage or threshold current can be controlled externally by light are arranged one-dimensionally, two-dimensionally, or three-dimensionally, and at least a portion of the light generated from each light-emitting element is incident on other light-emitting elements in the vicinity of each light-emitting element, and a clock line that applies a voltage or current from the outside is connected to each light-emitting element (Patent Document 1).

[0003] A self-scanning light-emitting device is also known in which a light-emitting element is constructed with a pnpnpn six-layer semiconductor structure, electrodes are provided on the p-type first layer and n-type sixth layer at both ends and on the p-type third layer and n-type fourth layer in the center, and the pn layer is made to function as a light-emitting diode and the pnpn fourth layer is made to function as a thyristor (Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 01-238962 [Patent Document 1] JP 2001-308385 A Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to reduce the size of a light emitting device compared to a case in which electrode portions are arranged in the longitudinal direction of the light emitting device. [Means for solving the problem]

[0006] In order to solve the above problem, the light emitting device according to claim 1 comprises: A substrate; A light emitting section including a plurality of light emitting elements; a transfer unit that outputs a signal for controlling a light-emitting state of the light-emitting element; an electrode unit for inputting and outputting a signal for driving the transfer unit; Equipped with The substrate has a rectangular shape having long and short sides, The electrode sections are arranged along the short sides of the substrate, sandwiching the transfer section. Cage , an area of ​​the light emitting portion is larger than an area of ​​the transfer portion; The light-emitting unit includes a plurality of light-emitting element groups each of which includes a plurality of light-emitting elements and which are independently drivable and are arranged two-dimensionally; a light-emitting electrode portion that is commonly connected to the plurality of light-emitting elements and supplies a current, the light-emitting electrode portion being formed across the long side of the substrate, and the electrode portion and the light-emitting electrode portion being arranged side by side in the longitudinal direction; It is characterized by:

[0014] In order to solve the above problem, the following claims are provided: 2 The measuring device described in A light emitting device according to claim 1; a light receiving unit that receives reflected light from an object irradiated with light from the light emitting device; a processing unit that measures a three-dimensional shape of the object based on a time from when light is irradiated from the light emitting device to when the light is received by a light receiving unit of the optical device, thereby measuring the three-dimensional shape of the object; Equipped with It is characterized by: Effect of the Invention

[0015] According to the invention described in claim 1, the size of the light emitting device can be made smaller than when the electrode portion is disposed in the longitudinal direction of the light emitting device. At the same time, the light-emitting electrode and the wiring connected to the electrode can be placed closer to each other. .

[0024] Claim 2 According to the invention described in the above, a measuring device capable of measuring a three-dimensional shape is provided. [Brief description of the drawings]

[0025] [Figure 1] FIG. 2 is a diagram showing an example of a planar layout of the light emitting device according to the embodiment. [Diagram 2]1 is a schematic equivalent circuit diagram of a light emitting device according to an embodiment of the present invention. [Diagram 3] FIG. 13 is a diagram showing an example of a planar layout of a light emitting device according to Modification 1. [Figure 4] FIG. 13 is a diagram showing an example of a planar layout of a light emitting device according to Modification 2. [Diagram 5] 1 is a diagram showing an example of a planar layout of a light emitting device according to an embodiment of the present invention, focusing on a transfer section; [Figure 6] FIG. 1 is a diagram showing a cross-sectional structure of a light emitting device. [Figure 7] FIG. 1 is a diagram illustrating a measurement device using a light emitting device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] The present invention will be described in more detail below with reference to the drawings, showing embodiments and specific examples, but the present invention is not limited to these embodiments and specific examples. In addition, in the following explanation using the drawings, it should be noted that the drawings are schematic and the ratios of the dimensions, etc. may differ from the actual ones, and in order to make it easier to understand, illustrations other than those of parts necessary for the explanation have been omitted as appropriate.

[0027] (1) Overall configuration of the light-emitting device Fig. 1 is a diagram showing an example of a planar layout of a light emitting device 100 according to this embodiment, and Fig. 2 is a schematic equivalent circuit diagram of the light emitting device 100 according to this embodiment. In Fig. 2, a control unit 200 that controls the light emitting device 100 is also shown. As shown in FIG. 1, the light emitting device 100 includes a substrate 110, a light emitting section 120 consisting of a plurality of light emitting elements, a transfer section 130 that controls the light emission of the light emitting elements, and a common signal line 150 that connects the light emitting section 120 and the transfer section 130 to each other.

[0028] The light emitting unit 120 includes a plurality of laser diodes that emit laser light as an example of a light emitting element. The light emitting device 100 is configured as a self-scanning light emitting element array (SLED: Self-Scanning Light Emitting Device) as described below. In this embodiment, the laser diode is, for example, a vertical cavity surface emitting laser (VCSEL). In the following description, the light emitting element is described as a VCSEL, but may be another light emitting device such as a light emitting diode (LED).

[0029] (2) Equivalent circuit of light-emitting device First, the functional configuration of the light emitting device 100 will be described with reference to the equivalent circuit in FIG. The light emitting unit 120 includes a plurality of VCSELs. As an example, one VCSEL group is made up of 15 VCSELs. In FIG. 1, 12 VCSEL groups (VCSEL groups #1 to #12) are shown, and in the equivalent circuit diagram of FIG. 2, four VCSEL groups (VCSEL groups #1 to #4) which are a part of the VCSEL groups are shown. In this embodiment, the 15 VCSELs included in one VCSEL group are arranged adjacent to each other, so that the area of ​​the VCSEL group is not dispersed. The light emitting device 100 includes a drive thyristor S for each VCSEL group. The VCSEL group and the drive thyristor S are connected in series. The drive thyristor S is also assigned the letter "i", which is the number of the VCSEL group. For example, the drive thyristor S included in VCSEL group #1 is drive thyristor S1.

[0030] The light emitting device 100 further includes a plurality of transfer thyristors T, a plurality of coupling diodes D, a plurality of power supply line resistors Rg, a start diode SD, and current limiting resistors R1 and R2. Here, when the plurality of transfer thyristors T are to be distinguished from one another, they are distinguished by adding "i", which is the number of the VCSEL group, such as the transfer thyristors T1, T2, T3, .... The same applies to the coupling diode D and the power supply line resistor Rg. As will be described later, for example, the transfer thyristor T1 is provided so as to correspond to the VCSEL group #1. FIG. 2 shows a portion where i corresponds to 1 to 4. "i" in the light emitting device 100 may be a predetermined number. For example, it may be 128, 512, 1024, etc. The number of the transfer thyristors T may be the same as the number of the VCSEL groups. The number of the transfer thyristors T may be greater than or less than the number of the VCSEL groups.

[0031] The transfer thyristors T are arranged in the order of transfer thyristors T1, T2, T3, ..., and the coupling diodes D are arranged in the order of coupling diodes D1, D2, D3, .... The coupling diode D1 is provided between the transfer thyristor T1 and the transfer thyristor T2. The other coupling diodes D are arranged in the same manner. Moreover, the power supply line resistances Rg are also arranged in the order of power supply line resistances Rg1, Rg2, Rg3, ....

[0032] The VCSEL and the coupling diode D are two-terminal elements having an anode and a cathode. The drive thyristor S and the transfer thyristor T are three-terminal elements having an anode, a cathode, and a gate. Here, the gate of the transfer thyristor T is referred to as gate Gt, and the gate of the drive thyristor S is referred to as gate Gs. When distinguishing between them, the letter "i" is added as described above. The portion composed of the VCSEL is referred to as the light-emitting unit 120.

[0033] Next, the connection relationship of each element (VCSEL, drive thyristor S, transfer thyristor T, etc.) will be described. As described above, VCSELij and drive thyristor Si are connected in series. That is, the anode of the drive thyristor Si is connected to a reference potential Vga (ground potential (GND), etc.), and the cathode is connected in parallel to the anode of VCSELij. The cathodes of VCSELij are commonly connected to a light-up signal line 56 to which a light-up signal ΦI that controls VCSELij to a light-emitting or non-light-emitting state is supplied.

[0034] The reference potential Vga is supplied via a Vga terminal (see FIGS. 1 and 3, which will be described later) provided on the rear surface of a substrate 110 constituting the light emitting device 100, as will be described later.

[0035] The anode of the transfer thyristor T is connected to a reference potential Vga. The cathodes of the odd-numbered transfer thyristors T1, T3, ... are connected to a transfer signal line 52. The transfer signal line 52 is connected to a Φ1 terminal, which is one of the electrode pads constituting the electrode unit 140, via a current limiting resistor R1. The even-numbered transfer thyristors T2, T4, . . . have their cathodes connected to a transfer signal line 53. The transfer signal line 53 is connected to a Φ2 terminal, which is one of the electrode pads constituting the electrode unit 140, via a current limiting resistor R2.

[0036] The coupling diodes D are connected in series with each other. That is, the cathode of one coupling diode D is connected to the anode of the adjacent coupling diode D. The start diode SD has an anode connected to the transfer signal line 53 and a cathode connected to the anode of the coupling diode D1.

[0037] The cathode of the start diode SD and the anode of the coupling diode D1 are connected to the gate Gt1 of the transfer thyristor T1. The cathode of the coupling diode D1 and the anode of the coupling diode D2 are connected to the gate Gt2 of the transfer thyristor T2. The same applies to the other coupling diodes D.

[0038] The gate Gt of the transfer thyristor T is connected to a power line 51 via a power line resistance Rg. The power line 51 is connected to a Vgk terminal, which is one of the electrode pads constituting the electrode unit 140. The gate Gti of the transfer thyristor Ti is connected to the gate Gsi of the drive thyristor Si.

[0039] The following describes the configuration of the control unit 200. The control unit 200 generates signals such as a lighting signal ΦI and supplies them to the light emitting device 100. The light emitting device 100 operates according to the signals supplied via the electrode unit 140. The control unit 200 is configured with an electronic circuit. For example, the control unit 200 may be an integrated circuit (IC) configured to control the operation of the light emitting device 100. The control unit 200 includes a transfer signal generating unit 210, a lighting signal generating unit 220, a power supply potential generating unit 230, and a reference potential generating unit 240.

[0040] The transfer signal generating unit 210 generates transfer signals Φ1 and Φ2, supplies the transfer signal Φ1 to a Φ1 terminal as an example of a transfer signal electrode of the light emitting device 100, and supplies the transfer signal Φ2 to a Φ2 terminal as an example of a transfer signal electrode of the light emitting device 100. The lighting signal generating unit 220 generates a lighting signal ΦI and supplies it to a ΦI terminal, which is an example of a lighting signal electrode, of the light emitting device 100 via a current limiting resistor RI. The current limiting resistor RI may be provided within the light emitting device 100. Furthermore, if the current limiting resistor RI is not necessary for the operation of the light emitting device 100, the current limiting resistor RI does not need to be provided.

[0041] The power supply potential generating unit 230 generates a power supply potential Vgk and supplies it to a Vgk terminal as an example of a power supply electrode of the light emitting device 100. The reference potential generating unit 540 generates a reference potential Vga and supplies it to a Vga terminal as an example of a power supply electrode of the light emitting device 100. The power supply potential Vgk is, for example, −3.3 V. As described above, the reference potential Vga is, for example, the ground potential (GND). The transfer section is driven based on signals from the power supply electrodes and transfer signal electrodes.

[0042] The transfer signals Φ1 and Φ2 generated by the transfer signal generating unit 210 and the light-up signal ΦI generated by the light-up signal generating unit 220 will be described later.

[0043] In the light emitting device 100 shown in FIG. 2, 15 VCSELij (j=1 to 15) are connected as a VCSEL group to one transfer thyristor Ti via a drive thyristor Si. As described later, when the transfer thyristor Ti is turned on, it sets the drive thyristor Si connected to the transfer thyristor Ti to be able to transition to the on state. Furthermore, when the drive thyristor Si is turned on, the VCSELij emits light. Note that the transfer thyristors Ti are driven to transfer the on state in the order of "i". In other words, the on state propagates sequentially in the transfer thyristors Ti. In this way, the transfer thyristors Ti cause the VCSEL group to emit light sequentially. Here, one VCSEL group is made up of a plurality of VCSELs (15 in this embodiment). The VCSEL group is connected to each transfer thyristor T, and the plurality of VCSELs included in the VCSEL group emit light in parallel. Note that, in the example shown in FIG. 2, each VCSEL group includes the same number of VCSELs (15 in this embodiment), but the number of VCSELs may differ between the VCSEL groups.

[0044] It is preferable for a VCSEL to oscillate in a low-order single transverse mode (single mode). In the single mode, the intensity profile of the light (emitted light) emitted from the light-emitting point of the VCSEL (light output port 310 in FIG. 3 described later) is unimodal (having one intensity peak). On the other hand, a VCSEL that oscillates in multiple transverse modes (multimodes) including higher orders is likely to have a distorted intensity profile, such as multiple peaks. Also, in the single mode, the spread angle of the light (emitted light) emitted from the light-emitting point is smaller than in the multimode.

[0045] The smaller the area of ​​the light-emitting point of a VCSEL, the more likely it is to oscillate in a single transverse mode (single mode). For this reason, single-mode VCSELs have low optical output. If the area of ​​the light-emitting point is increased in an attempt to increase optical output, it is likely to transition to multimode. For this reason, multiple VCSELs are grouped into a VCSEL group, and the multiple VCSELs in the VCSEL group are made to emit light in parallel, thereby increasing the optical output.

[0046] (3) Planar layout of the light-emitting device Returning to Fig. 1, we will first describe the planar layout of the transfer section 130 and the electrode section 140 in the light emitting device 100. The substrate 110 of the light emitting device 100 is rectangular with long sides 110a and short sides 110b, and in Fig. 1, the x direction is the long side direction and the y direction is the short side direction. As shown in FIG. 1, in the light emitting device 100, the electrode section 140 is disposed along the short side 110b of the substrate 110 with the transfer section 130 interposed therebetween.

[0047] The electrode section 140 comprises a Φ1 terminal and a Φ2 terminal as transfer signal electrodes receiving transfer signals Φ1 and Φ2 generated by the transfer signal generating section 210 of the control section 200, a Vgk terminal as a power supply electrode receiving a power supply potential Vgk generated by the power supply potential generating section 230, and a Vga terminal receiving a reference potential Vga generated by the reference potential generating section 540, and each terminal is a bonding pad.

[0048] In the transfer section 130 of the light emitting device 100, a transfer signal line 52 extending from the Φ1 terminal of the electrode section 140, a transfer signal line 53 extending from the Φ2 terminal, a power supply line 51 extending from the Vgk terminal, and a reference potential line 54 extending from the Vga terminal are formed as conductive patterns. In the transfer unit 130, the cathodes of the odd-numbered transfer thyristors T1, T3, . . . are connected to a transfer signal line 52, and the cathodes of the even-numbered transfer thyristors T2, T4, .

[0049] 1, the Φ1 terminal and Φ2 terminal for inputting and outputting the transfer signals Φ1 and Φ2, and the Vgk terminal and Vga terminal for inputting and outputting the power supply potential Vgk and the reference potential Vga are arranged in a straight line with respect to the transfer section 130. This makes it possible to reduce the size of the light emitting device 100 compared to the case where the electrode section 140 is arranged in the long side direction of the substrate 110.

[0050] In addition, the ΦI terminal, which is a light-up signal electrode that receives the light-up signal ΦI generated by the light-up signal generating unit 220 and controls the VCSELij to emit or not emit light, is disposed along the long side 110a of the substrate 110, sandwiching the light-emitting unit 120 therebetween. As shown in FIG. 1, the ΦI terminal is formed along the longitudinal direction of the light-emitting unit 120, and is connected to the electrode unit 1 4 0 are arranged side by side in the longitudinal direction of the substrate 110. 4 The wiring leading to 0 can be brought closer.

[0051] The light emitting section 120 is configured with 12 VCSEL groups (VCSEL groups #1 to #12) each consisting of 15 VCSELs, arranged in a 4×3 two-dimensional pattern with four in the x direction (first direction) and three in the y direction (second direction) intersecting (orthogonal) with the x direction, allowing for divided illumination. The area of ​​the light emitting section 120 is larger than the area of ​​the transfer section 140, allowing the light emission amount of the light emitting device 100 to be increased.

[0052] The transfer units 130 that output transfer signals to the VCSEL groups arranged two-dimensionally in the first and second directions are arranged along the short side 110b of the substrate 110, with the first direction transfer unit outputting transfer signals to the VCSEL groups in the first direction and the second direction transfer unit outputting transfer signals to the VCSEL groups in the second direction being united. In other words, none of the transfer units 130 are arranged in the long side direction (x direction) of the substrate 110. This allows the size of the light emitting device 100 to be reduced.

[0053] "Variation 1" FIG. 3 is a diagram showing an example of a planar layout of a light emitting device 100A according to the first modification. In the light emitting device 100A according to the first modification, the Φ1 terminal, Φ2 terminal for inputting and outputting the transfer signals Φ1, Φ2, and the Vgk terminal, Vga terminal for inputting and outputting the power supply potential Vgk and the reference potential Vga are arranged in a line in a direction intersecting (orthogonal to) the transfer section 130 between the control section 200 and the transfer section 130 as shown in Fig. 3. This makes it possible to reduce the size of the light emitting device 100 compared to the case where the electrode section 140 is arranged in the long side direction of the substrate 110.

[0054] "Variation 2" FIG. 4 is a diagram showing an example of a planar layout of a light emitting device 100B according to the second modification. In the light emitting device 100 according to the present embodiment, including the first modification, a case has been described in which the Vgk terminal and the Vga terminal for inputting and outputting the power supply potential Vgk and the reference potential Vga are provided, but the Vgk terminal and the Vga terminal can be omitted, and in that case, as shown in Fig. 4, one Φ1 terminal and one Φ2 terminal for inputting and outputting the transfer signals Φ1 and Φ2 may be disposed on either side of the transfer unit 130 between the control unit 200 and the transfer unit 130. This allows the size of the light emitting device 100 to be made smaller than when the electrode unit 140 is disposed in the long side direction of the substrate 110.

[0055] FIG. 5 is a diagram showing an example of a planar layout of the light emitting device 100 according to this embodiment, focusing on the transfer section 130. As shown in FIG. The light emitting device 100 is made of a semiconductor material capable of emitting laser light, for example, a GaAs-based compound semiconductor. As shown in a cross-sectional view (FIG. 6) described later, the light emitting device 100 is made of a semiconductor layer stack in which a plurality of GaAs-based compound semiconductor layers are stacked on a p-type GaAs substrate 110, and is made of a plurality of islands in which elements are separated by mesa etching. Here, the planar layout of the light emitting device 100 will be described using islands 301 to 306 shown in FIG. 5. Note that the islands 301, 302, and 303 are provided for each VCSEL group. Therefore, when the islands 301, 302, and 303 are to be distinguished from one another by one VCSEL group, the islands may be labeled as islands 301-i, 302-i, and 303-i, with "i" added as described above. Note that in FIG. 5, i indicates the range of 1 to 12. The number of VCSELs in the VCSEL group is labeled as "j" as described above. Here, j is 1 to 15. In this manner, the light emitting device 100 is constructed on a common semiconductor substrate and is miniaturized.

[0056] The island 301-i is provided with VCSELij and a drive thyristor Si. As shown in FIG. 6, which will be described later, the VCSELij and the drive thyristor Si are stacked. In FIG. 5, the VCSELij and the drive thyristor Si are expressed as VCSELij / Si. For example, when "i" is 1, it is expressed as VCSEL1j / S1. In FIG. 5, the islands 301-1, 301-4, and 301-12 are illustrated, and the other islands 301-i are omitted. In the island 301-i, 15 VCSELs are arranged.

[0057] The island 302-i is provided with a transfer thyristor Ti and a coupling diode Di. The islands 302-i are provided in parallel in the y direction (short side direction).

[0058] The island 303-i is provided with a power supply line resistance Rgi. The islands 303-i are arranged in parallel in the y direction (short side direction).

[0059] A start diode SD is provided in the island 304. A current limiting resistor R1 is provided in the island 305, and a current limiting resistor R2 is provided in the island 306.

[0060] (4) Cross-sectional structure of the light-emitting device Next, before describing the connection relationship of these islands 301 to 306, the cross-sectional structure of the islands 301 and 302 will be described. Fig. 6 is a diagram showing a cross-sectional structure of the light emitting device 100. Fig. 6 is a cross-sectional view of the light emitting device 100 taken along line AA in Fig. 5. In other words, the cross-sectional view shown in Fig. 6 is a cross section across the coupling diode D1, the transfer thyristor T1, VCSEL11 / S1, and VCSEL12 / S1 from the left side of the paper, and shows the portions of island 301-1 and island 302-1.

[0061] First, the island 301-1 in which the drive thyristor S and the VCSEL are provided will be described. Here, the drive thyristor S and the VCSEL are stacked (VCSEL11 / S1, VCSEL12 / S1). As shown in Fig. 6, a p-type anode layer (hereinafter referred to as p-anode layer, the same applies below) 11 constituting the drive thyristor S1, an n-type gate layer (n-gate layer) 12, a p-type gate layer (p-gate layer) 13, and an n-type cathode layer (n-cathode layer) 14 are stacked on a p-type GaAs substrate 110. That is, the drive thyristor S is configured with the p-anode layer 11 as the anode, the n-gate layer 12 as the n-gate, the p-gate layer 13 as the p-gate, and the n-cathode layer 14 as the cathode.

[0062] Next, a tunnel junction layer 15 is laminated on the n-cathode layer 14. Then, a p-type anode layer (p-anode layer) 16, a light-emitting layer 17, and an n-type cathode layer (n-cathode layer) 18 constituting the VCSEL 11 and the VCSEL 12 are laminated on the tunnel junction layer 15. That is, the VCSEL is configured with the p-anode layer 16 as the anode, the light-emitting layer 17 as the light-emitting layer, and the n-cathode layer 18 as the cathode. The drive thyristor S1, the VCSEL 11, and the VCSEL 12 are connected in series via a tunnel junction layer 15. The tunnel junction layer 15 will be described later.

[0063] In the VCSEL 11 and VCSEL 12 portions, the n-cathode layer 18, the light-emitting layer 17, and the p-anode layer 16 are removed by etching so as to expose the tunnel junction layer 15 around the VCSEL. Here, the cross-sectional shape of the VCSEL is circular. In other words, the VCSEL portion is formed in a cylindrical shape. Therefore, the VCSEL portion is referred to as a post 311 (see FIG. 5).

[0064] The p-anode layer 11, n-gate layer 12, p-gate layer 13, n-cathode layer 14 and tunnel junction layer 15 constituting the drive thyristor S are continuous between the VCSELs belonging to the VCSEL group #1.

[0065] Furthermore, in the island 301-1, in a portion where the tunnel junction layer 15 and the n cathode layer 14 are removed to expose the p gate layer 13, a p ohmic electrode 331 made of a metal material that easily forms ohmic contact with a p-type semiconductor layer such as the p gate layer 13 is provided as the gate Gs1 of the drive thyristor S1.

[0066] An n-ohmic electrode 321 made of a metal material that easily forms ohmic contact with an n-type semiconductor layer such as the n-cathode layer 18 is provided on the n-cathode layer 18 of the VCSEL. The n-ohmic electrode 321 is provided in a circular shape so as to surround the light emission aperture 310 (see FIG. 5).

[0067] The p anode layer 16 of the post 311 includes a current confinement layer 16b. Here, as an example, the p anode layer 16 is composed of three layers: a lower p anode layer 16a, a current confinement layer 16b, and an upper p anode layer 16c. The current confinement layer 16b is composed of a material with a high Al composition ratio, such as AlAs, and refers to a layer in which the electric resistance increases when Al becomes Al2O3 through oxidation, forming a portion through which a current does not easily flow (the black portion in FIG. 6).

[0068] Since the post 311 is cylindrical, when the current confinement layer 16b is oxidized from the side of the exposed p-anode layer 16, the oxidation proceeds from the periphery to the center in the circular cross section. By not oxidizing the center, the center in the cross section of the VCSEL becomes the current passing region 16d where current easily flows, and the periphery becomes the current blocking region 16e where current does not easily flow. The VCSEL emits light in a portion where the current path is restricted by the current passing region 16d of the light emitting layer 17. The area on the surface of the VCSEL corresponding to the current passing region 16d is the light emitting point and the light exit 310.

[0069] The current confinement layer 16b is provided in order to make the VCSEL oscillate in a low-order single transverse mode (single mode). In other words, the cross-sectional shape of the post 311 on which the VCSEL is formed is made circular and oxidized from the periphery, thereby making the cross-sectional shape of the light emission aperture 310 circular and reducing its area. In addition, the periphery of the VCSEL has many defects due to mesa etching, making it easy for non-radiative recombination to occur. Therefore, by providing the current blocking region 16e, the power consumed by non-radiative recombination is suppressed. This leads to low power consumption and improved light extraction efficiency. The light extraction efficiency is the amount of light that can be extracted per unit of power.

[0070] Next, the island 302-1 in which the transfer thyristor T1 and the coupling diode D1 are provided will be described. The transfer thyristor T1 is composed of a p-anode layer 11, an n-gate layer 12, a p-gate layer 13, and an n-cathode layer 14, similar to the drive thyristor S. That is, the transfer thyristor T1 is composed of the p-anode layer 11 as the anode, the n-gate layer 12 as the n-gate, the p-gate layer 13 as the p-gate, and the n-cathode layer 14 as the cathode. Here, a gate electrode (a p-ohmic electrode 332, described later) is provided on the p-gate layer 13.

[0071] The coupling diode D1 is composed of a p-gate layer 13 and an n-cathode layer 14. That is, the coupling diode D1 is composed of the p-gate layer 13 as the anode and the n-cathode layer 14 as the cathode.

[0072] In the island 302-1, the n-cathode layer 18, the light emitting layer 17, the p-anode layer 16, and the tunnel junction layer 15 are removed from the portion where the drive thyristor S and the VCSEL are stacked. Then, in the portion of the transfer thyristor T1 and the portion of the coupling diode D1, the n-cathode layer 14 is removed so that the n-cathode layer 14 remains as a post 312 and a post 313.

[0073] An n-ohmic electrode 322 is provided as a cathode electrode of the transfer thyristor T1 on the n-cathode layer 14 of the post 312. Similarly, an n-ohmic electrode 323 is provided as a cathode electrode of the coupling diode D1 on the n-cathode layer 14 of the post 313. A p-ohmic electrode 332 provided on the p-gate layer 13 functions as the gate Gt1 of the transfer thyristor T1 and the anode electrode of the coupling diode D1.

[0074] An interlayer insulating layer 21 is provided to cover the surface. A signal line 55 is provided on the interlayer insulating layer 21 via a through hole, connecting the p-ohmic electrode 331 (gate Gs1) provided on the island 301-1 and the p-ohmic electrode 332 (gate Gt1) provided on the island 302-1. A transfer signal line 52 connected to the n-ohmic electrode 322 is provided on the interlayer insulating layer 21. A transfer signal line 53 is provided on the interlayer insulating layer 21. A wiring 54-2 connected to the n-ohmic electrode 323 is provided on the interlayer insulating layer 21 via a through hole.

[0075] Furthermore, an interlayer insulating layer 22 is provided so as to cover the surface. A light-up signal line 56 is provided on the interlayer insulating layer 22, and is connected to an n-ohmic electrode 321 provided on the island 301-1 via a through hole provided in the interlayer insulating layer 22 and the interlayer insulating layer 21. In other words, the signal line 55 and the light-up signal line 56 form a multilayer wiring structure with the interlayer insulating layer 22 interposed therebetween.

[0076] If the interlayer insulating layers 21 and 22 have poor transparency to the emitted light of the VCSEL, the interlayer insulating layers 21 and 22 on the light emission aperture 310 may be replaced with a light emission layer having excellent transparency to the emitted light of the VCSEL.

[0077] The islands 301, 302, 303, 304, 305, and 306 are separated from one another by removing the surrounding semiconductor layer stack by etching down to the substrate 110. Note that the etching may be performed down to the p anode layer 11, or down to a part of the p anode layer 11 in the thickness direction.

[0078] Returning to FIG. 5, the other islands 303, 304, 305, and 306 will be described. A power line resistance Rg1 is configured in the island 303. In the island 303-1, the n-cathode layer 18, the light emitting layer 17, the p-anode layer 16, the tunnel junction layer 15, and the n-cathode layer 14 in the semiconductor layer stack are removed to expose the p-gate layer 13. A pair of p-ohmic electrodes is provided on the exposed p-gate layer 13. The p-gate layer 13 between the p-ohmic electrodes is used as a resistor.

[0079] A start diode SD is provided on the island 304. The n-cathode layer 18, the light-emitting layer 17, the p-anode layer 16, and the tunnel junction layer 15 in the semiconductor layer stack are removed from the island 304. The p-gate layer 13 is exposed except for the post 314 where the n-cathode layer 14 remains. In the start diode SD, the n-cathode layer 14 constituting the post 314 is the cathode, and the p-gate layer 13 is the anode. The n-ohmic electrode provided on the n-cathode layer 14 of the post 314 is the cathode electrode, and the p-ohmic electrode provided on the exposed p-gate layer 13 is the anode electrode.

[0080] A current limiting resistor R1 is provided in the island 305, and a current limiting resistor R2 is provided in the island 306. The islands 305 and 306 have the same configuration as the island 303, and the p-gate layer 13 between a pair of p-ohmic electrodes provided on the exposed p-gate layer 13 serves as the current limiting resistors R1 and R2, respectively.

[0081] The islands 301 to 306 and the connections between the islands will be described. As described above, the n-cathode layer 18, which is the cathode of the VCSEL provided on the post 311 of the island 301-1, is connected in parallel to the light-up signal line 56 via the n-ohmic electrode 321. The other islands 301 are similarly connected. The n-cathode layer 18, which is the cathode of the transfer thyristor T1 provided on the post 312 of the island 302-1, is connected to the transfer signal line 52 via an n-ohmic electrode 322. The same is true for the transfer thyristor T3 provided on the island 302-3. In other words, the cathode (n-cathode layer 18) of the odd-numbered transfer thyristor Ti is connected to the transfer signal line 52.

[0082] On the other hand, the cathode (n cathode layer 18) of the transfer thyristor T2 provided in the island 302-2 is connected to the transfer signal line 53. In other words, the cathode (n cathode layer 18) of the transfer thyristor Ti with the even number i is connected to the transfer signal line 53.

[0083] A p-ohmic electrode 331 serving as the gate Gs1 of the island 301-1 and a p-ohmic electrode 332 serving as the gate Gt1 of the island 302-1 are connected by a signal line 55-1. The cathode (n-cathode layer 18) of the coupling diode D1 provided on the post 313 of the island 302-1 is connected to a wiring 57-2 via an n-ohmic electrode 323. The wiring 57-2 is connected to the p-ohmic electrode of the adjacent island 302-2 and the p-ohmic electrode of the power supply line resistance Rg2 of the island 303-2. Incidentally, the signal from the signal line 55-1 is transmitted not only to the multiple VCSELs 11 but also to the VCSELs in group #1 such as VCSEL 12. Something equivalent to the signal line 55-1 is provided for each light-emitting element group, and the signal line 55-1 serves as a common signal line.

[0084] A p-ohmic electrode 333 (provided on the p-gate layer 13 in the same manner as the p-ohmic electrode 332 of the gate Gt1) provided on the island 302-1, one of the p-ohmic electrodes of the power supply line resistor Rg1 provided on the island 303-1, and an n-ohmic electrode which is the cathode electrode of the start diode SD provided on the island 304 are connected by wiring 57-1.

[0085] The other p-ohmic electrode of the power supply line resistor Rg1 of the island 303-1 is connected to the power supply line 51. The power supply line 51 is connected to the Vgk terminal. The other islands 303 are similarly connected.

[0086] The transfer signal line 52 is connected to one p-ohmic electrode of the current limiting resistor R1 of the island 305. The other p-ohmic electrode of the current limiting resistor R1 is connected to the Φ1 terminal. The transfer signal line 53 is connected to the p-ohmic electrode of the start diode SD of the island 303 and is also connected to one p-ohmic electrode of the current limiting resistor R2 of the island 306. The other p-ohmic electrode of the current limiting resistor R2 of the island 306 is connected to the Φ2 terminal.

[0087] In the above, the islands 301-1, 302-1, and 303-1 have been described as examples, but the other islands 301, 302, and 303 are similar.

[0088] (5) Operation of the light-emitting device (5.1) Thyristor Next, a description will be given of the operation of the drive thyristor S and the transfer thyristor T. The drive thyristor S and the transfer thyristor T are collectively referred to as thyristors. The thyristor is configured by laminating a p-anode layer 11, an n-gate layer 12, a p-gate layer 13, and an n-cathode layer 14. As described above, the thyristor is a semiconductor element having three terminals, an anode, a cathode, and a gate, and is configured by laminating a p-type semiconductor layer (p-anode layer 11, p-gate layer 13) and an n-type semiconductor layer (n-gate layer 12, n-cathode layer 14) made of GaAs, GaAlAs, AlAs, or the like. In other words, the thyristor has a pnpn structure. Here, as an example, the forward potential (diffusion potential) Vd of the pn junction configured by the p-type semiconductor layer and the n-type semiconductor layer is set to 1.5 V.

[0089] As an example, the reference potential Vga of the p anode layer 11 is set to 0V as a high-level potential (hereinafter referred to as "H"), and the power supply potential Vgk supplied to the Vgk terminal (see FIG. 2) is set to -3.3V as a low-level potential (hereinafter referred to as "L"). Therefore, these may be expressed as "H (0V)" and "L (-3.3V)". As shown in FIG. 2, the Vgk terminal is connected to the gate (gate Gt1 when the thyristor is the transfer thyristor T1) via a power supply line resistance Rg1.

[0090] In the off state, when no current flows between the anode and cathode, the thyristor has a threshold voltage When a lower potential (a negative potential with a larger absolute value) is applied to the cathode, the device transitions to the on state (the transistor Here, the threshold voltage of the thyristor is the forward voltage of the pn junction from the gate potential. This is the value minus the forward potential Vd (1.5 V). When the thyristor is turned on, the gate of the thyristor has a potential close to that of the anode. In this case, the anode is 0V, so the gate is assumed to be 0V. Also, the cathode of a thyristor in the on state has a potential close to the potential obtained by subtracting the forward potential Vd (1.5V) of the pn junction from the potential of the anode (the absolute value is denoted as the holding voltage). In this case, the anode is 0V, so the cathode of a thyristor in the on state has a potential close to -1.5V (a negative potential with an absolute value greater than 1.5V). In this case, the holding voltage is assumed to be 1.5V.

[0091] A thyristor in the on state will maintain its on state when a potential lower than the potential required to maintain the on state (a negative potential with a large absolute value) is continuously applied to the cathode and a current sufficient to maintain the on state (maintenance current) is supplied. On the other hand, a thyristor in the on state transitions to the off state (turns off) when the cathode reaches a potential higher than the potential required to maintain the on state (a potential close to -1.5V as mentioned above) (a negative potential with a small absolute value, 0V or a positive potential).

[0092] (5.2) Operation of stacked drive thyristors and VCSELs Next, the operation of the stacked drive thyristor S and VCSEL will be described. Here, the VCSEL has a turn-on voltage of 1.5V. In other words, if a voltage of 1.5V or more is applied between the anode and cathode of the VCSEL, the VCSEL will emit light. The light-up signal ΦI is 0V ("H (0V)") or -3.3V ("L (-3.3V)"). 0V is the potential that turns the VCSEL off, and -3.3V is the potential that turns the VCSEL from the off state to the on state.

[0093] When the VCSEL is to be switched from the OFF state to the ON state, the lighting signal ΦI is set to "L (-3.3V)". At this time, when -1.5V is applied to the gate Gs of the driving thyristor S, the threshold voltage of the driving thyristor S becomes -3V, which is the potential of the gate Gs (-1.5V) minus the forward potential Vd (1.5V) of the pn junction. At this time, since the lighting signal ΦI is -3.3V, the driving thyristor S turns on and switches from the OFF state to the ON state, and the VCSEL also switches from the OFF state to the ON state. In other words, the VCSEL emits light by laser oscillation. Then, since the voltage (holding voltage Vr) applied to the driving thyristor S in the ON state is 1.5V, 1.8V is applied to the VCSEL. Since the rise voltage of the VCSEL is 1.5V, the VCSEL continues to emit light.

[0094] On the other hand, when the lighting signal ΦI is set to 0 V, both the driving thyristor S and the VCSEL connected in series When the voltage at the terminal becomes 0V, the driving thyristor S transitions from the on state to the off state (turns off), and the VCSEL stops emitting light.

[0095] (6) Measuring equipment The light emitting device 100 according to the present embodiment described above can be used for optical measurement. FIG. 7 is a diagram illustrating a measuring device 1 using a light emitting device 100. As shown in FIG. The measurement device 1 includes the above-mentioned light emitting device 100, a light receiving unit 101 that receives light, and a processing unit 102 that processes data. An object to be measured (object) 103 is placed facing the measurement device 1. In Fig. 7, the object to be measured 103 is a person as an example, and Fig. 7 is a view seen from above.

[0096] As described above, the light emitting device 100 lights up the two-dimensionally arranged VCSEL group, and emits light that spreads in a cone shape with the light emitting device 100 at the center, as indicated by the solid line.

[0097] The light receiving unit 101 is a device that receives light reflected by a measurement object 103. The light receiving unit 101 receives light directed toward the light receiving unit 101 as indicated by a dashed line. The light receiving unit 101 may be an imaging device that receives light from two-dimensional directions.

[0098] The processing unit 102 is configured as a computer equipped with an input / output unit for inputting and outputting data. The processing unit 102 processes information related to light to calculate the distance to the measurement object 103 and the three-dimensional shape of the measurement object 103. The processing unit 102 of the measurement device 1 controls the light emitting device 100 to emit light from the light emitting device 100 for a short period of time. That is, the light emitting device 100 emits light in a pulsed form, and the processing unit 102 calculates the optical path length from when the light is emitted from the light emitting device 100, reflected by the measurement object 103, to when it reaches the light receiving unit 101, based on the time difference between when the light emitting device 100 emits light and when the light receiving unit 101 receives the reflected light from the measurement object 103. The positions of the light emitting device 100 and the light receiving unit 101 and the interval between them are determined in advance. Therefore, the processing unit 102 measures the distance from the light emitting device 100 and the light receiving unit 101, or the distance from a point used as a reference (hereinafter, referred to as a reference point) to the measurement object 103. The reference point is a point (point) provided at a predetermined position from the light emitting device 100 and the light receiving unit 101.

[0099] This method is based on the arrival time of light and is called the time-of-flight (TOF) method. If this method is performed for a plurality of points on the measurement object 103, the three-dimensional shape of the measurement object 103 is measured. As described above, the emitted light from the light emitting device 100 spreads two-dimensionally and is irradiated onto the measurement object 103. Then, the reflected light from the portion of the measurement object 103 that is close to the light emitting device 100 is incident on the light receiving unit 101 first. When the imaging device for acquiring the above-mentioned two-dimensional image is used, a bright spot is recorded in the frame image at the portion where the reflected light reaches. From the bright spots recorded in a series of a plurality of frame images, the optical path length is calculated for each bright spot. Then, the distance from the light emitting device 100 or the light receiving unit 101 or the distance from the reference point is calculated. In this manner, the three-dimensional shape of the measurement object 103 is calculated.

[0100] As another method, the light emitting device 100 of this embodiment can also be used in a photometry method using a structured light method. The device used is almost the same as the measurement device 1 using the light emitting device 100 shown in Fig. 9. The difference is that the pattern of light irradiated onto the measurement object 103 is an innumerable number of light dots (random pattern), which are received by the light receiving unit 101. The processing unit 102 processes information about the light. Here, the processing method does not involve calculating the time difference as described above, but calculates the amount of positional deviation of countless light dots to calculate the distance to the measurement object 103 and the three-dimensional shape of the measurement object 103. Conventionally, the light source used in this method is a randomly arranged two-dimensional VCSEL array or the like, but the random pattern to be irradiated is about 1 to 4 predetermined patterns (structured light fixed method). On the other hand, the light emitting device 100 of the present embodiment can irradiate light in more random patterns because the light dots to be irradiated can be freely set by an external signal (structured light programmable method).

[0101] The measuring device 1 as described above can be applied to calculating the distance to an object. It can also be applied to identifying an object by calculating the shape of the object. And it can be applied to face recognition by calculating the shape of a person's face. Furthermore, by loading it into a car, it can be applied to detecting obstacles in front, behind, or to the sides. In this way, the measuring device 1 can be widely used to calculate distance, shape, and the like.

[0102] In the above embodiment, the light emitting device 100 is used for measurement, but the present invention is not limited thereto. The light emitting device may be used together with an optical transmission path as a light emitting device for optical transmission, or may be used as a light emitting device for biometric authentication that emits light toward the inside of a target object.

[0103] In the above embodiment, the VCSEL group is configured so that light emitting elements of the same group are adjacent to each other. In this way, the area of ​​the VCSEL group is not dispersed, and the configuration such as simplifying the common signal line is easy. In this case, since the light emitting elements connected to the same common signal line can be regarded as one light emitting group, the area of ​​the VCSEL group is dispersed, and the shape of the VCSEL group does not need to be divided into neat sections.

[0104] In the above embodiment, an example has been described in which the on state is propagated in sequence in the transfer thyristor Ti, whereby the transfer thyristor Ti sequentially lights up the VCSEL groups. However, the transfer thyristor Ti may further have a memory unit, and after the on state is propagated in sequence in the transfer thyristor Ti, a signal may be temporarily stored in the memory unit and the signal may be sent simultaneously to the multiple VCSEL groups, causing the multiple VCSEL groups to light up simultaneously. [Explanation of symbols]

[0105] 1 Measuring device, 101 Light receiving unit, 102 Processing unit, 103 Measurement object 100, 100A, 100B... Light-emitting device 110... Substrate 120 Light emitting part S: Drive thyristor, VCSEL: Vertical-cavity surface-emitting laser element 130...Transfer section Φ1, Φ2... Transfer signal, ΦI... Illumination signal, D... Coupling diode, SD... Start diode, T... Transfer thyristor, Rg... Power line resistance, R1, R2... Current limiting resistor 140...electrode section Φ1...Φ1 terminal, Φ2...Φ2 terminal, Vgk...Vgk terminal, Vga...Vga terminal 150 Common signal line 51 power supply line, 52, 53 transfer signal line, 54 reference potential line, 56 lighting signal line 200...Control section 210 transfer signal generating section, 220 lighting signal generating section, 230 power supply potential generating section, 240 reference potential generating section 301~306···Island

Claims

1. A substrate; A light emitting section including a plurality of light emitting elements; a transfer unit that outputs a signal for controlling a light-emitting state of the light-emitting element; an electrode unit for inputting and outputting a signal for driving the transfer unit; Equipped with The substrate has a rectangular shape having long and short sides, The electrode units are disposed along the short sides of the substrate with the transfer unit therebetween, an area of ​​the light emitting portion is larger than an area of ​​the transfer portion; The light-emitting unit includes a plurality of light-emitting element groups each of which includes a plurality of light-emitting elements and which are independently drivable and are arranged two-dimensionally; a light-emitting electrode portion that is commonly connected to the plurality of light-emitting elements and supplies a current, the light-emitting electrode portion being formed across the long side of the substrate, and the electrode portion and the light-emitting electrode portion being arranged side by side in the longitudinal direction; A light emitting device characterized by:

2. A light emitting device according to claim 1 ; a light receiving unit that receives reflected light from an object irradiated with light from the light emitting device; A processing unit that measures a distance from the light emitting device to the object or a three-dimensional shape of the object based on a time from when the light is irradiated from the light emitting device to the object to when the light is received by the light receiving unit. A measuring device characterized by:

Images