阅读说明：本技术 光源设备和感测模块 (Light source device and sensing module ) 是由 田畑满志 増田贵志 汤胁武志 大场康雄 于 2019-08-05 设计创作，主要内容包括：本发明对设置有发光部的光源设备中的温度升高进行抑制,在发光部中排列多个基于垂直腔面发射激光器的发光元件。根据发明的光源设备设置有发光部和驱动部,在所述发光部中排列有多个垂直腔面发射激光器的发光元件,所述驱动部使所述发光部的所述多个发光元件发光,其中在驱动部中的具有驱动元件的区域的至少一部分被布置为不与发光部重叠。(The present invention suppresses a temperature rise in a light source apparatus provided with a light emitting section in which a plurality of light emitting elements based on vertical cavity surface emitting lasers are arrayed. A light source device according to the invention is provided with a light emitting section in which light emitting elements of a plurality of vertical cavity surface emitting lasers are arrayed, and a driving section that causes the plurality of light emitting elements of the light emitting section to emit light, wherein at least a part of a region having the driving element in the driving section is arranged so as not to overlap with the light emitting section.)

1. A light source apparatus, comprising:

a light emitting section in which light emitting elements of a plurality of vertical cavity surface emitting lasers are arranged; and

a driving section configured to cause the plurality of light emitting elements of the light emitting section to emit light, wherein

At least a part of a region including a driving element in the driving portion is arranged so as not to overlap with the light emitting portion.

2. The light source apparatus of claim 1, wherein

A chip in which the light emitting portion is formed is mounted on a chip in which the driving portion is formed, and at least a part of the region of the driving portion including the driving element is arranged so as not to overlap with the light emitting element of the light emitting portion.

3. The light source apparatus of claim 1, wherein

The driving section includes a plurality of wiring layers in which leads for electrically connecting the driving element and the light emitting element are formed.

4. The light source apparatus of claim 3, wherein

The leads are formed such that the distance between the driving element and the light emitting element connected to each other is longer toward the lower layer of the wiring layer.

5. The light source apparatus of claim 4, wherein

A plurality of regions including a driving element are disposed in the driving part.

6. The light source apparatus of claim 3, wherein

As the length of the lead increases, a portion whose cross-sectional area increases when taken in a cross-section in a plane perpendicular to the extending direction of the lead is formed in the lead.

7. The light source apparatus of claim 6, wherein

In the portion of the lead, a width increases in a thickness direction of the wiring layer.

8. The light source apparatus of claim 6, wherein

In the portion of the lead, a width increases in a planar direction of the wiring layer.

9. The light source apparatus of claim 6, wherein

The cross-sectional area of the lead provided in the wiring layer is larger toward the lower layer of the wiring layer.

10. The light source apparatus of claim 1, wherein

The driving section is configured to be capable of individually driving a light emitting operation for each predetermined unit of the plurality of light emitting elements.

11. The light source apparatus of claim 1, wherein

The light emitting section is configured to emit light in synchronization with a frame period of an image sensor configured to receive light emitted by the light emitting section and reflected by an object.

12. A sensing module, comprising:

a light source device provided with a light emitting section in which light emitting elements of a plurality of vertical cavity surface emitting lasers are arrayed, and a driving section configured to cause the plurality of light emitting elements of the light emitting section to emit light, wherein at least a part of a region including a driving element in the driving section is arranged so as not to overlap with the light emitting section; and

an image sensor configured to capture an image by receiving light emitted by the light emitting section and reflected by an object.

Technical Field

The present technology relates to a light source device provided with a light emitting section in which light emitting elements of a plurality of vertical cavity surface emitting lasers are arrayed, and a sensing module provided with an image sensor that captures an image by receiving light emitted by the light emitting section and then reflected by an object.

Background

A Vertical Cavity Surface Emitting Laser (VCSEL) is called a laser light emitting element as described in patent documents 1 and 2 below.

The VCSEL light emitting element is configured such that an oscillator is formed perpendicular to a surface of a semiconductor substrate and laser light is emitted in a vertical direction, and in recent years, the VCSEL has been widely used as a light source when measuring a distance to an object according to, for example, a structured light (STL) method and a time-of-flight (ToF) method.

CITATION LIST

Patent document

Patent document 1: japanese patent application laid-open No. 2012-195436

Patent document 2: japanese patent application laid-open No. 2015-103727.

Disclosure of Invention

Problems to be solved by the invention

Here, in the case of measuring the distance to the object according to the STL method or the ToF method, a light source in which a plurality of VCSEL light emitting elements are arranged in a two-dimensional array is used. Specifically, the object is irradiated with light emitted from a plurality of light emitting elements, and the distance to the object is measured based on an image obtained by receiving reflected light from the object.

When the distance is measured in this way, the plurality of light emitting elements are caused to emit light, but the temperature of a chip forming the light emitting elements is easily increased by heat generated by a driving circuit or the like for causing the light emitting elements to emit light, which may cause a heat-induced failure such as a decrease in emission efficiency of the light emitting elements. Moreover, the temperature of the light emitting element is increased due to emission, and the heat thus generated may cause deterioration of circuit characteristics in a driving circuit that drives the light emitting element.

The present technology has been devised in view of the above circumstances, and an object thereof is to suppress a temperature rise in a light source device provided with a light emitting section in which light emitting elements of a plurality of vertical cavity surface emitting lasers are arranged.

Problem solving scheme

A light source device according to the present technology includes a light emitting section in which light emitting elements of a plurality of vertical cavity surface emitting lasers are arrayed, and a driving section configured to cause the plurality of light emitting elements of the light emitting section to emit light, wherein at least a part of a region including the driving element in the driving section is arranged so as not to overlap with the light emitting section.

With this configuration, heat generated from the driving element and transferred to the light emitting element is reduced. In addition, heat generated by the light emitting element and transferred to the driving circuit of the driving portion is also reduced.

In the light source device according to the present technology described above, it is desirable that a chip in which the light emitting section is formed is mounted on a chip in which the driving section is formed, and at least a part of a region of the driving section including the driving element is arranged so as not to overlap with the light emitting element of the light emitting section.

With this configuration, the wiring connecting the light emitting section and the driving section can be shortened, and an increase in wiring resistance can be alleviated. Further, the region including the driving element may be disposed at a distance from the light emitting element generating heat.

In the above-described light source apparatus according to the present technology, it is desirable that the driving section includes a plurality of wiring layers in which leads for electrically connecting the driving element and the light emitting element are formed.

With this configuration, it is possible to arrange the lead while maintaining the cross-sectional area of the lead, and to alleviate an increase in wiring resistance.

In the above-described light source apparatus according to the present technology, it is desirable that the lead lines are formed such that the distance between the driving element and the light emitting element connected to each other is longer toward the lower layer of the wiring layer.

With this configuration, when the lead is drawn from a lower layer to an upper layer, it is possible to avoid a situation in which the lead of the upper layer interferes with the lead drawing of the lower layer.

In the light source apparatus according to the present technology described above, it is desirable to provide a plurality of regions including the driving elements in the driving section.

By dividing the region including the driving element into a plurality of regions, the length of the wiring connecting the driving element and the light emitting element can be shortened.

In the above-described light source apparatus according to the present technology, it is desirable that, as the length of the lead wire increases, a portion whose cross-sectional area increases when taken in a cross-section in a plane perpendicular to the extending direction of the lead wire is formed in the lead wire.

Since the lead line is lengthened due to an increase in distance from the driving element to the light emitting element, wiring resistance increases. For this reason, the cross-sectional area of the lead is increased to mitigate the increase in wiring resistance.

In the above-described light source apparatus according to the present technology, it is desirable to increase the width in the thickness direction of the wiring layer in the portion of the lead.

By increasing the width in the thickness direction of the wiring layer, the cross-sectional area of the lead increases, and the increase in wiring resistance is alleviated.

In the light source apparatus according to the present technology described above, it is desirable to increase the width of the portion of the lead in the plane direction of the wiring layer.

By increasing the width in the plane direction of the wiring layer, the cross-sectional area of the lead increases, and the increase in wiring resistance is alleviated.

In the above-described light source apparatus according to the present technology, it is desirable that the cross-sectional area of the lead provided in the wiring layer is larger toward the lower layer of the wiring layer.

The further down the wiring layer, the greater the distance from the driving element to the light emitting element, and as a result, the longer the lead becomes. With this configuration, the wiring resistance of the lead provided in the lower layer increases. For this reason, the cross-sectional area of the lead in the lower layer is increased to mitigate the increase in wiring resistance.

In the light source device of the present technology described above, it is desirable to configure the driving section to be capable of driving the light emitting operation of each predetermined unit of the plurality of light emitting elements, respectively.

The predetermined unit may be a unit containing a single light emitting element, a unit containing a block of a plurality of light emitting elements, or the like.

With this configuration, for example, the light emission drive current can be set to turn on/off light emission individually for each light emitting element or in units of blocks as a plurality of light emitting element groups.

In the above-described light source device according to the present technology, it is desirable that the light emitting section is configured to emit light in synchronization with a frame period of the image sensor configured to receive light emitted by the light emitting section and reflected by the object.

With this configuration, in order to deal with a case where a distance is measured by irradiating an object with light emitted by the light emitting section and receiving the light with the image sensor, the light emitting element can be caused to emit light at an appropriate timing according to the frame period of the image sensor.

Further, the sensing module according to the above-described present technology includes a light source device provided with a light emitting section in which light emitting elements of a plurality of vertical cavity surface emitting lasers are arrayed, and a driving section configured to cause the plurality of light emitting elements of the light emitting section to emit light, wherein at least a part of a region including the driving element in the driving section is arranged so as not to overlap with the light emitting section, and an image sensor configured to capture an image by receiving light emitted by the light emitting section and reflected by an object.

Actions similar to those of the light source device according to the present technology described above are also obtained by such a driving method and sensing module.

Effects of the invention

According to the present technology, suppression of temperature rise can be obtained for a light source apparatus provided with a light emitting section in which light emitting elements of a plurality of vertical cavity surface emitting lasers are arrayed.

Note that the effect described herein is not necessarily restrictive, and may be any effect described in the present disclosure.

Drawings

Fig. 1 is a diagram showing an exemplary configuration of a distance measuring apparatus as an embodiment of a light source apparatus according to the present technology.

Fig. 2 is a diagram illustrating a technique of measuring a distance according to a structured light (STL) method.

Fig. 3 is a diagram showing an exemplary circuit configuration of a light source device as an embodiment.

Fig. 4 is a diagram showing a variation of the driving circuit provided in the light source device as an embodiment.

Fig. 5 is a diagram showing a circuit configuration of a variation of the light source device as the embodiment.

Fig. 6 is a diagram showing an exemplary substrate configuration of a light source device as an embodiment.

Fig. 7 is a diagram showing another exemplary substrate configuration of a light source device as an embodiment.

Fig. 8 is a diagram showing still another exemplary substrate configuration of a light source device as an embodiment.

Fig. 9 is a diagram showing an exemplary configuration of a temperature sensor provided in a light source device as an embodiment.

Fig. 10 is a diagram illustrating an exemplary structure of a light emitting portion provided in a light source device as an embodiment.

Fig. 11 is a diagram illustrating another exemplary structure of a light emitting portion provided in a light source device as an embodiment.

Fig. 12 is a diagram showing a configuration relationship between the light emitting section and the driving section as an embodiment.

Fig. 13 is a diagram showing another arrangement relationship between the light emitting section and the driving section as an embodiment.

Fig. 14 is a diagram showing an exemplary configuration of a light emitting section and a driving section as an embodiment.

Fig. 15 is a diagram showing another arrangement relationship between the light emitting section and the driving section as an embodiment.

Fig. 16 is a diagram for explaining a lead connecting a light emitting section and a driving section as an example.

Fig. 17 is another diagram for explaining a lead wire connecting the light emitting section and the driving section as an example.

Fig. 18 is another diagram for explaining a lead wire connecting the light emitting section and the driving section as an example.

Detailed Description

Hereinafter, embodiments according to the present technology will be described with reference to the drawings in the following order.

<1. configuration of distance measuring apparatus >

<2. distance measurement technique >

<3. Circuit configuration relating to light emission drive >

<4. variations in substrate arrangement >

<5. exemplary VCSEL Structure >

<6. arrangement relationship between light emitting element and driving transistor >

<7 > lead line connecting light emitting element and driving transistor >

<8. summary of examples and modifications >

<9 > the present technology >

<1. configuration of distance measuring apparatus >

Fig. 1 shows an exemplary configuration of a distance measuring apparatus 1 as an embodiment of a light source apparatus according to the present technology.

As shown in the figure, the distance measuring apparatus 1 is provided with a light emitting section 2, a driving section 3, a power supply circuit 4, a light emitting side optical system 5, an imaging side optical system 6, an image sensor 7, an image processing section 8, a control section 9, and a temperature detection section 10.

The light emitting section 2 emits light from a plurality of light sources. As will be described later, the light emitting section 2 in this example includes Vertical Cavity Surface Emitting Laser (VCSEL) light emitting elements 2a as a light source, and these light emitting elements 2a are arranged in a predetermined pattern (e.g., matrix).

The driving section 3 includes a circuit for driving the light emitting section 2.

The power supply circuit 4 generates a power supply voltage (a drive voltage Vd described later) for the drive section 3 based on an input voltage (an input voltage Vin described later) from a power supply such as a battery (not shown) provided in the distance measuring apparatus 1. The driving section 3 drives the light emitting section 2 based on the power supply voltage.

The light emitted by the light emitting section 2 irradiates the object S as a distance measurement target through the light emitting-side optical system 5. Thereafter, reflected light from the subject S among the light emitted in this manner is incident on the imaging surface of the image sensor 7 through the imaging side optical system 6.

The image sensor 7 is an image sensor such as a Charge Coupled Device (CCD) sensor or a Complementary Metal Oxide Semiconductor (CMOS) sensor, which receives the reflected light from the subject S incident through the imaging side optical system 6 as described above, and converts the received light into an output electric signal.

The image sensor 7 performs processing such as Correlated Double Sampling (CDS) processing and Automatic Gain Control (AGC) processing on an electric signal obtained by photoelectric conversion of received light, and further performs analog/digital (a/D) conversion processing. The image signal is then output as digital data to the downstream image processing section 8.

In addition, the image sensor 7 in this example outputs a frame synchronization signal Fs to the driving section 3. With this configuration, the driving section 3 can cause the light emitting elements 2a of the light emitting section 2 to emit light at a timing according to the frame period of the image sensor 7.

The image processing section 8 is configured as an image processor such as a Digital Signal Processor (DSP). The image processing unit 8 performs various image signal processes on the digital signal (image signal) input from the image sensor 7.

The control section 9 is provided with an information processing apparatus such as a microcomputer including a component such as a Central Processing Unit (CPU), a Read Only Memory (ROM), a Random Access Memory (RAM), or a DSP. The control section 9 controls the driving section 3 for controlling the light emitting operation of the light emitting section 2, and controls the image forming operation of the image sensor 7.

The control section 9 includes a function as a distance measuring section 9 a. The distance measuring section 9a measures the distance to the object S based on the image signal input through the image processing section 8 (i.e., the image signal obtained by receiving the reflected light from the object S). The distance measuring section 9a in this example measures distances to different portions of the object S, thereby enabling recognition of the three-dimensional shape of the object S.

Here, a specific technique of measuring the distance in the distance measuring apparatus 1 will be described later in more detail.

The temperature detection unit 10 detects the temperature of the light emitting unit 2. As the temperature detection unit 10, for example, a configuration in which a diode is used to detect the temperature can be adopted.

In this example, information on the temperature detected by the temperature detection section 10 is supplied to the driving section 3, thereby enabling the driving section 3 to drive the light emitting section 2 based on the information on the temperature.

<2. distance measurement technique >

As the distance measuring technique in the distance measuring apparatus 1, for example, a distance measuring technique according to a structured light (STL) method or a time-of-flight (ToF) method may be employed.

The STL method measures a distance based on an image obtained by imaging the subject S irradiated with light having a predetermined bright/dark pattern (e.g., a dot pattern or a grating pattern).

Fig. 2 is a diagram illustrating the STL method.

In the STL method, for example, the subject S is irradiated with pattern light Lp having a dot pattern as shown in a of fig. 2. The pattern light Lp is divided into a plurality of blocks BL, and a different dot pattern is assigned to each block BL (the dot pattern is not repeated in the block BL).

B of fig. 2 is a diagram illustrating the principle of distance measurement according to the STL method.

In the example here, the wall W and the frame BX placed on the front are taken as the object S, and the object S is irradiated with the pattern light Lp. In the figure, "G" schematically indicates the angle of view of the image sensor 7.

Further, "BLn" in the drawing indicates light from a certain block BL in the pattern light Lp, and "dn" indicates a dot pattern of the block BLn appearing in the captured image obtained by the image sensor 7.

Here, in the case where the frame BX in front of the wall W does not exist, the dot pattern of the block BLn appears at the position "dn'" in the figure in the captured image. In other words, the position where the pattern of the block BLn appears in the captured image differs between the case where the frame BX exists and the case where the frame BX does not exist, more specifically, distortion occurs in the pattern.

The STL method is a method of thus obtaining the shape and depth of the object S by using how the illumination pattern is deformed by the physical shape of the object S. Specifically, the STL method is a method of acquiring the shape and depth of the object S from a pattern deformation mode.

In the case of adopting the STL method, for example, an Infrared (IR) image sensor having a global shutter is used as the image sensor 7. In addition, in the case of the STL method, the distance measuring section 9a controls the driving section 3 so that the light emitting section 2 emits pattern light, and detects pattern deformation in the image signal obtained by the image processing section 8, and calculates the distance based on the manner of the pattern deformation.

Next, the ToF method measures the distance to the target by detecting the time of flight (time difference) of light emitted by the light emitting section 2, reflected by the target, and reaching the image sensor 7.

In the case of adopting a so-called direct ToF method as the ToF method, a Single Photon Avalanche Diode (SPAD) is used as the image sensor 7, and the light emitting section 2 is pulse-driven. In this case, the distance measuring section 9a calculates a time difference from emission to reception of light emitted by the light emitting section 2 and received by the image sensor 7 based on the image signal input through the image processing section 8, and calculates distances to different parts of the object S based on the time difference and the speed of light.

Note that, in the case of adopting a so-called indirect ToF method (phase difference method) as the ToF method, an IR image sensor is used as the image sensor 7, for example.

<3. Circuit configuration relating to light emission drive >

Fig. 3 shows an exemplary circuit configuration of the light source device 100 including the light emitting section 2, the driving section 3, and the power supply circuit 4 shown in fig. 1. Note that fig. 3 shows the image sensor 7 and the control section 9 shown in fig. 1 in addition to an exemplary circuit configuration of the light source device 100.

In the present example, the light emitting section 2, the driving section 3, and the power supply circuit 4 are formed on a common substrate (substrate B described below). Here, a configuration unit that includes at least the light emitting portion 2 and is formed on a substrate common to the light emitting portion 2 is referred to as a light source device 100.

As shown in the figure, the light source apparatus 100 is provided with a temperature detection section 10 in addition to the light emitting section 2, the driving section 3, and the power supply circuit 4.

The light emitting section 2 is provided with a plurality of VCSEL light emitting elements 2a as described above. In fig. 3, the number of the light emitting elements 2a is regarded as "4" for convenience, but the number of the light emitting elements 2a of the light emitting section 2 is not limited thereto, and is sufficiently at least two or more.

The power supply circuit 4 is provided with a DC/DC converter 40, and generates a driving voltage Vd (DC voltage) for the driving section 3 to drive the light emitting section 2 based on an input voltage Vin supplied as a DC voltage.

The drive section 3 is provided with a drive circuit 30 and a drive control section 31.

The drive circuit 30 includes a drive transistor Q1 and a switch SW for each light emitting element 2a, and a transistor Q2 and a constant current source 30 a.

Field Effect Transistors (FETs) are used to drive transistor Q1 and transistor Q2, and in this example, P-channel Metal Oxide Semiconductor (MOS) FETs or MOSFETs are used.

The driving transistor Q1 is connected in parallel relation to an output line of the DC/DC converter 40, i.e., a supply line of the driving voltage Vd, and the transistor Q2 is connected in parallel with the driving transistor Q1.

Specifically, the source of each of the driving transistor Q1 and the driving transistor Q2 is connected to the output line of the DC/DC converter 40. The drain of each of the driving transistors Q1 is connected to the anode of the corresponding one of the light emitting elements 2a in the light emitting section 2.

As shown in the figure, the cathode of each light emitting element 2a is Grounded (GND).

The drain of the transistor Q2 is grounded through the constant current source 30a, and the gate is connected to a node between the drain and the constant current source 30 a.

The gate of each drive transistor Q1 is connected to the gate of transistor Q2 through a respective switch SW.

In the drive circuit 30 having the above configuration, the drive transistor Q1 with the switch SW turned on is turned on, the drive voltage Vd is applied to the light emitting element 2a connected to the turned-on drive transistor Q1, and the light emitting element 2a emits light.

At this time, the drive current Id flows to the light emitting element 2a, but in the drive circuit 30 having the above configuration, the drive transistor Q1 and the transistor Q2 form a current mirror circuit, and the current value of the drive current Id is set to a value corresponding to the current value of the constant current source 30 a.

The drive control section 31 controls the on/off state of the light emitting element 2a by controlling the on/off state of the switch SW in the drive circuit 30.

The frame synchronization signal Fs is supplied from the image sensor 7 to the drive control section 31, so that the drive control section 31 synchronizes the on timing and the off timing of the light emitting element 2a with the frame period of the image sensor 7.

The drive control unit 31 can control the on/off state of the light emitting element 2a based on an instruction from the control unit 9.

In addition, the drive control section 31 in this example controls the on/off state of the light emitting element 2a based on the temperature of the light emitting section 2 detected by the temperature detection section 10.

Here, fig. 3 shows an example of a configuration in which the driving transistor Q1 is provided on the anode side of the light emitting element 2a, but like the driving circuit 30A shown in fig. 4, a configuration in which the driving transistor Q1 is provided on the cathode side of the light emitting element 2a may be adopted.

In this case, the anode of each light emitting element 2a in the light emitting section 2 is connected to the output line of the DC/DC converter 40.

For each of the driving transistor Q1 and the transistor Q2 forming the current mirror circuit, an N-channel MOSFET is used. The drain and gate of the transistor Q2 are connected to the output line of the DC/DC converter 40 through the constant current source 30a, and the source is grounded.

The drain of each driving transistor Q1 is connected to the cathode of the corresponding light emitting element 2a, and the source is grounded. The gate of each drive transistor Q1 is connected to the gate and drain of transistor Q2 through each corresponding switch SW.

Also in this case, the drive control section 31 can turn on/off the light emitting element 2a by controlling the on/off state of the switch SW.

Fig. 5 shows an exemplary configuration of the light source device 100A as a modification.

The light source device 100A has a power supply circuit 4A instead of the power supply circuit 4 and a driving section 3A instead of the driving section 3.

The power supply circuit 4A includes a plurality of (two, in the illustrated example) DC/DC converters 40. The input voltage Vin1 is provided to the DC/DC converter 40, while the input voltage Vin2 is provided to the other DC/DC converter 40. The drive unit 3A is provided with a plurality of drive circuits 30 that receive input of drive voltages Vd from different DC/DC converters 40. As shown in the drawing, in each of the drive circuits 30, a variable current source 30b is provided instead of the constant current source 30 a. The variable current source 30b is a current source having a variable current value.

In this case, the light emitting elements 2a of the light emitting section 2 are divided into a plurality of light emitting element groups on/off-controlled by different drive circuits 30.

In this case, the drive control section 31 controls the on/off state of the switch SW in each of the drive circuits 30.

Like the light source device 100A, by adopting a configuration in which at least one pair of the DC/DC converter 40 and the drive circuit 30 is reproduced as a plurality of subsystems, the drive current Id of the light emitting element 2a can be set to different values for each subsystem. For example, by making the voltage value of the driving voltage Vd and the current value of the variable current source 30b different for each subsystem, the value of the driving current Id may be made different for each subsystem. Further, in the configuration in which the DC/DC converter 40 keeps the drive current Id constant, the value of the drive current Id can be made different for each subsystem by making the target value of the constant current control for each DC/DC converter 40 different.

In the case of adopting the configuration like fig. 5, it is conceivable that the values of the driving voltage Vd and the driving current Id are made different for each subsystem according to factors such as the light emission intensity distribution and the temperature distribution in the light emitting section 2. For example, it is conceivable to take measures such as increasing the drive current Id and also raising the drive voltage Vd for the subsystem corresponding to the high temperature position in the light emitting section 2.

<4. variations in substrate arrangement >

Here, the light source apparatus 100 may employ the configurations shown in fig. 6 to 8.

As shown in a of fig. 6, the light source apparatus 100 may adopt a configuration in which a chip Ch2 containing a circuit as the light emitting section 2, a chip Ch3 containing a circuit as the driving section 3, and a chip Ch4 containing the power supply circuit 4 are formed on the same substrate B.

In addition, the driving section 3 and the power supply circuit 4 may also be formed in the same chip Ch34, and in this case, the light source apparatus 100 may take a configuration in which the chip Ch2 and the chip Ch34 are formed on the same substrate B, as shown in B of fig. 6.

A configuration may also be adopted in which the chip Ch is mounted on another chip Ch.

In this case, the light source apparatus 100 may adopt, for example, a configuration as shown in a of fig. 7 in which the chip Ch3 and the chip Ch4 on which the chip Ch2 is mounted are formed on the substrate B, a configuration as shown in B of fig. 7 in which the chip Ch3 on which the chip Ch2 and the chip Ch4 are mounted is formed on the substrate B, or a configuration as shown in C of fig. 7 in which the chip Ch34 on which the chip Ch2 is mounted is formed on the substrate B.

In addition, the light source device 100 may also adopt a configuration including the image sensor 7.

For example, a of fig. 8 shows an example of the configuration of the light source apparatus 100 in which the chip Ch2, the chip Ch3, and the chip Ch4, and the chip Ch7 containing a circuit serving as the image sensor 7 are formed on the same substrate B.

Further, B of fig. 8 shows an example of the configuration of the light source apparatus 100, in which the chip Ch34 on which the chip Ch2 is mounted and the chip Ch7 are formed on the same substrate B.

Note that the light source device 100A described above may also adopt configurations similar to those described using fig. 6 to 8.

Here, in the temperature detection unit 10, for example, in the case where the chip Ch2 is formed on the substrate B as in a of fig. 6, B of 6, and a of 8, it is sufficient that a temperature detection element such as a diode is formed at a position near the chip Ch2 in the substrate B (for example, a position near the chip Ch2 on the substrate B).

Further, in the case of mounting the chip Ch2 on another chip Ch, it is sufficient to form a temperature detection element in a position close to the chip Ch2 (e.g., a position under the chip Ch2) in the other chip Ch, as shown in fig. 7 a to 7C and fig. 8B.

The temperature detection section 10 may include a plurality of temperature sensors 10a including temperature detection elements such as diodes.

Fig. 9 shows an exemplary configuration of the temperature sensor 10a in the case where the temperature detection section 10 includes a plurality of temperature sensors 10 a.

In the example of fig. 9, the plurality of temperature sensors 10a are not concentrated at a single position, but are dispersed in a plane parallel to the plane in which the light emitting elements 2a are arranged. Specifically, the plurality of temperature sensors 10a may be arranged such that 1 temperature sensor 10a is disposed for each light-emitting block including a predetermined number of light-emitting elements 2a, for example, a2 × 2 block including a total of 4 light-emitting elements 2 a. In this case, the temperature sensors 10a may be arranged at equal intervals on a plane parallel to the plane in which the light emitting elements 2a are arranged.

Note that, although fig. 9 shows an example in which 4 temperature sensors 10a are arranged with respect to 9 light emitting elements 2a, the number of the light emitting elements 2a and the number of the temperature sensors 10a arranged are not limited thereto.

Further, by dispersing the plurality of temperature sensors 10a as in the example of fig. 9, the in-plane temperature distribution of the light emitting section 2 can be detected. Further, different temperatures may be detected for different regions of the light emitting surface, and by increasing the number of the temperature sensors 10a disposed, different temperatures may be detected for the respective light emitting elements 2 a.

<5. exemplary VCSEL Structure >

Next, an exemplary structure of the chip Ch2 in which the light emitting portion 2 is formed will be described with reference to fig. 10 and 11.

Fig. 10 shows an exemplary structure of the chip Ch2 in the case of being formed on the substrate B as in a of fig. 6, B of fig. 6, and a of fig. 8, and fig. 11 shows an exemplary structure of the chip Ch2 in the case of being mounted on another chip Ch as in a of fig. 7 to C of fig. 7 and B of fig. 8.

Note that, as an example, fig. 10 and 11 show an exemplary structure corresponding to a case where the drive circuit 30 is inserted to the anode side of the light emitting element 2a (see fig. 3).

As shown in fig. 10, in the chip Ch2, a portion corresponding to each light emitting element 2a is formed as a mesa (mesa) M.

The semiconductor substrate 20 serves as a substrate of the chip Ch2, and a cathode electrode Tc is formed on the lower side of the semiconductor substrate 20. For the semiconductor substrate 20, for example, a gallium arsenide (GaAs) substrate is used.

On the semiconductor substrate 20, in each mesa M, a first multilayer reflective layer 21, an active layer 22, a second multilayer reflective layer 25, a contact layer 26, and an anode electrode Ta are formed in this order from bottom to top.

The current constriction layer 24 is formed in a part (particularly, a lower part) of the second multilayer reflective layer 25. Also, a portion including the active layer 22 sandwiched between the first multilayer reflective layer 21 and the second multilayer reflective layer 25 functions as a resonator 23.

The first multilayer reflective layer 21 is formed using a compound semiconductor exhibiting N-type conductivity, and the second multilayer reflective layer 25 is formed using a compound semiconductor exhibiting P-type conductivity.

The active layer 22 serves as a layer for generating laser light, and the current confinement layer 24 serves as a layer for effectively injecting current into the active layer 22 and achieving a lens effect.

After the formation of the mesa M, the current constriction layer 24 is selectively oxidized in an unoxidized state, and includes a central oxidized region (also referred to as a selectively oxidized region) 24a and an unoxidized region 24b unoxidized around the oxidized region 24 a. In the current constriction layer 24, the oxidized region 24a and the unoxidized region 24b form a current constriction structure, and a current is conducted to the current constriction region as the unoxidized region 24 b.

The contact layer 26 is provided to ensure ohmic contact with the anode electrode Ta.

The anode electrode Ta is formed on the contact layer 26 in an annular (ring) shape or the like that is open at the center, for example, when the substrate B is viewed in plan view. In the contact layer 26, a portion where the anode electrode Ta is not formed on the top serves as an opening 26 a.

The light generated in the active layer 22 travels back and forth within the resonator 23 and is then emitted to the outside through the opening 26 a.

Here, the cathode electrode Tc in the chip Ch2 is grounded through a ground lead Lg formed in the wiring layer of the substrate B.

Further, in the drawing, a pad Pa denotes a pad for an anode electrode formed on the substrate B. The pad Pa is connected to the drain of any one of the driving transistors Q1 included in the driving circuit 30 through a lead Ld formed in the wiring layer of the substrate B.

In the figure, the anode electrode Ta is shown to be connected to a single pad Pa through an anode lead La formed on a chip Ch2 and a bonding wire BW for only one light-emitting element 2a, but the pad Pa and the lead Ld are formed for each light-emitting element 2a on a substrate B, and further, the anode lead La is formed for each light-emitting element 2a on a chip Ch2, and the anode electrodes Ta of the respective light-emitting elements 2a are connected to the respective pads Pa through the respective anode leads La and bonding wires BW.

Next, in the case of fig. 11, the back-side illumination chip Ch2 is used as the chip Ch 2. In other words, instead of emitting light in the upward direction (surface direction) of the semiconductor substrate 20 like the example in fig. 10, a type of chip Ch2 that emits light in the backward direction of the semiconductor substrate 20.

In this case, an opening for light emission is not formed in the anode electrode Ta, and an opening 26a is not formed in the contact layer 26.

In chip Ch3 (or chip Ch 34; the same applies to the description of fig. 11 below) forming driving section 3 (driving circuit 30), pad Pa for establishing electrical connection with anode Ta is formed for each light emitting element 2 a. In the wiring layer of the chip Ch3, a lead Ld is formed for each pad Pa. Although omitted from the illustration, each pad Pa is connected to the drain of the corresponding drive transistor Q1 in the drive circuit 30 formed in the chip Ch3 through these leads Ld.

Further, in the chip Ch2, the cathode electrode Tc is connected to the electrode Tc1 and the electrode Tc2 via leads Lc1 and Lc2, respectively. The electrode Tc1 and the electrode Tc2 are electrodes connected to a pad Pc1 and a pad Pc2 formed in the chip Ch3, respectively.

In the wiring layer of the chip Ch3, a ground lead Lg1 connected to the pad Pc1 and a ground lead Lg2 connected to the pad Pc2 are formed. Although not shown, these ground leads Lg1 and Lg2 are grounded.

The connection between each anode electrode Ta in chip Ch2 and each pad Pa in chip Ch3 and the connection between electrodes Tc1 and Tc2 in chip Ch2 and pads Pc1 and Pc2 in chip Ch3 are established by respective solder bumps Hb.

In other words, the mounting of chip Ch2 on chip Ch3 is realized in this case by so-called flip-chip mounting.

<6. arrangement relationship between light emitting element and driving transistor >

Next, fig. 12 to 15 will be used to describe the configuration relationship between the light emitting portion 2 and the drive circuit 30 in the case where the chip Ch2 is mounted on the chip Ch3 (or the chip Ch 34; the same applies to the following description), as shown in fig. 7 a to 7C and fig. 8B in the light source apparatus 100.

In the present embodiment, the back side illumination chip Ch2 shown in fig. 11 is used as an example. In this example, a structure corresponding to the case where the drive circuit 30 is inserted into the anode side of the light emitting element 2a as shown in fig. 3 is adopted.

Note that the chip Ch2 is not limited to the back-illumination type, and may be structured as shown in fig. 10. As in the drive circuit 30A shown in fig. 4, the drive transistor Q1 may be provided on the cathode side of the light-emitting element 2 a.

In the drive circuit 30 of the drive section 3 of fig. 3, the drive transistor Q1 whose switch SW is turned on, the drive voltage Vd is applied to the light emitting element 2a of the light emitting section 2 connected to the turned-on drive transistor Q1, and the light emitting element 2a emits light.

Like the distance measuring apparatus 1 described above, when measuring a distance by causing the light emitting portions 2 in which the plurality of VCSEL light emitting elements 2a are arrayed to emit light, the plurality of light emitting elements 2a are caused to emit light simultaneously or in a time-division manner.

When such light emission is performed, the driving transistor Q1 in the driving circuit 30 of the chip Ch3 generates heat, which makes the temperature of the chip Ch2 in which the light emitting element 2a is formed easy to rise, and depending on the ambient temperature, which may cause a heat-induced failure such as a decrease in the emission efficiency of the light emitting element 2 a.

In addition, the temperature of the light emitting element 2a increases due to light emission, and the heat thus generated may cause deterioration in circuit characteristics of the driving circuit 30 that drives the light emitting element 2 a.

Therefore, fig. 12 will be used to describe the configuration relationship between the light emitting section 2 (chip Ch2) and the driving section 3 (chip Ch3) to avoid interference due to mutual heat. A of fig. 12 is a diagram schematically showing the arrangement relationship of the chip Ch2 and the chip Ch3 provided on the substrate B, and B of fig. 12 is a cross-sectional view schematically showing the internal structure of the chip Ch3 on which the chip Ch2 is mounted.

As shown in a of fig. 12, 3 regions (hereinafter, also referred to as driving transistor placement regions ar) including driving transistors Q1 for causing the light-emitting elements 2a to emit light are provided in the chip Ch3 in a state where the chip Ch2 is mounted on the chip Ch 3. As shown in B of fig. 12, a plurality of driving transistors Q1 are provided in each driving transistor placement region ar of the driving circuit 30. In the drawing, all the driving transistor placement regions ar are provided at positions overlapping the plane of the chip Ch 2.

Note that although an example in which three driving transistor placement regions ar are provided is described here as an example for convenience of explanation, the driving transistor placement regions ar are not limited to three, and one or more driving transistor placement regions ar may be provided (the same applies to the following description).

In such a configuration, in the case where the plurality of light emitting elements 2a are caused to emit light simultaneously or in a time-division manner, the corresponding drive transistor placement regions generate heat. Therefore, the temperature of the chip Ch2 in contact with the driving transistor placement region ar increases with this heat generation.

Further, the plurality of light emitting elements 2a provided in the light emitting section 2 emit light simultaneously or in a time-division manner to generate heat, and the heat raises the temperature of the driving circuit 30 included in the driving transistor placement region ar.

Therefore, in the present embodiment, the driving transistor placement region ar is disposed at a position not overlapping with the chip Ch2 containing the light emitting element 2 a.

Fig. 13 shows an example of this configuration. A of fig. 13 is a diagram schematically showing the arrangement relationship of chip Ch2 and chip Ch3, and B of fig. 13 is a cross-sectional view schematically showing the internal structure of chip Ch3 on which chip Ch2 is mounted.

As shown in a of fig. 13 and B of fig. 13, two driving transistor placement regions ar are provided in the chip Ch3, the driving transistor placement regions ar being arranged to face each other with the chip Ch2 therebetween. At this time, the driving transistor placement region ar is arranged so as not to overlap with the plane of the chip Ch2 (light emitting section 2).

In this way, by disposing the driving transistor placement region ar at a position not lower than the lower side of the chip Ch2, the distance between the driving transistor Q1 of the driving transistor placement region ar and the chip Ch2 is increased, and the influence of heat generated by the driving transistor Q1 on the light emitting section 2 can be reduced. Further, the influence of heat generated when the light emitting element 2a provided in the light emitting section 2 emits light on the drive circuit 30 of the drive transistor placement area ar can be reduced.

In this way, since the influence of heat can be reduced by disposing the driving transistor placement region ar at a position away from the light emitting element 2a of the heat generating light emitting part 2, a part of the light emitting part 2 (chip Ch2) can be mounted on the driving part 3 (chip Ch3) so as to overlap the driving transistor placement region ar as long as the light emitting element 2a is configured not to overlap the driving transistor placement region ar.

Similarly, since the influence of heat can be reduced by disposing the light emitting section 2 at a position of the driving transistor Q1 distant from the driving transistor placement region ar generating heat, the light emitting section 2 (chip Ch2) may be mounted on the driving section 3 (chip Ch3) so as to overlap a part of the driving transistor placement region ar as long as the driving transistor Q1 is configured not to overlap with the light emitting section 2.

Further, in mounting the light emitting section 2 (chip Ch2) to the driving section 3 (chip Ch3), in order to prevent heat from concentrating at a single position, it is desirable to arrange the light emitting element 2a and the driving transistor Q1 so as not to overlap.

Also, by arranging the arranged driving transistor placement regions ar in a plurality of dispersed manners, such as by arranging the driving transistor placement regions ar at positions facing each other with the chip Ch2 therebetween, as shown in a of fig. 13, heat dissipation of each driving transistor placement region ar is improved, and a temperature rise in the driving transistor Q1 can be alleviated. With this configuration, the influence of heat generated by the driving transistor Q1 on the chip Ch2 can be reduced.

Note that the position of the driving transistor placement region ar in the chip Ch3 is not limited to the above, and various modes can be conceived. Fig. 14 shows an example of the configuration of the driving transistor placement region ar in the chip Ch 3.

For example, as shown in a of fig. 14, the driving transistor placement region ar may be arranged at a position not overlapping with the chip Ch2 in a single combination region in the chip Ch 3.

Also, as shown in B of fig. 14, the driving transistor placement region ar may be disposed along a first edge of the chip Ch2, or may be disposed along an edge adjacent to the first edge.

Further, as shown in C of fig. 14, it is also conceivable to arrange the driving transistor placement region ar so as to surround the chip Ch 2.

Also, the driving transistors Q1 in all the driving transistor placement regions ar are not necessarily disposed so as not to overlap with the chip Ch 2. In other words, the drive transistor placement region ar may also be set to overlap with the chip Ch2 as long as the temperature rise in the chip Ch2 does not exceed a value that would cause a malfunction.

For example, as shown in a of fig. 15 and B of fig. 15, in the case where three driving transistor placement regions ar are provided in the chip Ch3, two of the driving transistor placement regions ar may be provided at positions facing each other with the chip Ch2 therebetween, and the remaining single driving transistor placement region ar may be provided to overlap with the chip Ch2 (light emitting section 2). In this case, some of the driving transistors Q1 are arranged at positions overlapping with the chip Ch 2.

<7 > lead line connecting light emitting element and driving transistor >

Next, the structure of the lead line Lt for electrically connecting the light-emitting element 2a and the driving transistor Q1 will be described with reference to fig. 16 and 17. For the lead line Lt, for example, a metal lead such as a Cu lead is used.

If the wiring resistance value of the lead line Lt rises, the rise time of the signal pulse increases, which may cause phenomena such as an increase in power consumption due to ohmic loss and a rise in temperature associated therewith. Therefore, it is necessary to form the lead to mitigate an increase in wiring resistance of the lead Lt.

Fig. 16 is a cross-sectional view schematically showing chip Ch3 on which chip Ch2 is mounted.

As shown in a of fig. 16, the chip Ch3 is formed in a multilayer structure, and includes a plurality of wiring layers Ly1, Ly2, Ly3, and the like. The chip Ch3 may also be configured as a single-layer structure, but a multi-layer structure is desirable. Note that, hereinafter, a component such as an insulating layer will be omitted from the description to avoid confusion, and the driving transistor Q1 will be schematically illustrated.

The reason why the chip Ch3 has a multilayer structure is that the light emitting section 2 is provided with hundreds of light emitting elements 2a, and if it is attempted to provide leads Lt for connecting these light emitting elements 2a to the driving transistor Q1 in a single layer structure, the wiring cross-sectional area SA per lead Lt (hereinafter also simply referred to as cross-sectional area SA) becomes very small, making it difficult to secure a sufficient area to mitigate an increase in wiring resistance per lead Lt.

Here, the wiring cross-sectional area means a cross-sectional area when taken in a plane perpendicular to the extending direction of the lead. The extending direction is a direction in which the lead line Lt extends from the driving transistor Q1 to the light emitting element 2a, and for example, is a longitudinal direction of the lead line Lt.

Although not shown, the chip Ch3 according to the present embodiment has 7 wiring layers Ly.

In the drive transistor placement region ar of the chip Ch3, a drive transistor Q1 is provided in each wiring layer Ly, and the drain of each drive transistor Q1 is connected to the anode of a corresponding one of the light emitting elements 2a in the light emitting section 2 through a wire Lt.

The driving transistor Q1 provided in the uppermost wiring layer Ly1 is connected to a predetermined light emitting element 2a located near the periphery of the chip Ch2 (i.e., the light emitting element 2a spaced apart from the driving transistor Q1 by a short distance) via a wire Lt 1.

Further, the driving transistor Q1 in the wiring layer Ly2 provided below the wiring layer Ly1 is connected to a predetermined light emitting element 2a more inside than the light emitting element 2a connected in the wiring layer Ly1 through a wire Lt 2.

Further, the driving transistor Q1 in the wiring layer Ly3 provided below the wiring layer Ly2 is connected to a predetermined light emitting element 2a more inside than the light emitting element 2a connected in the wiring layer Ly2 through a wire Lt 3.

Therefore, as the wiring layer Ly goes to a lower layer, the distance from the driving transistor Q1 to the light emitting element 2a increases, and the length of the wire Lt connecting the driving transistor Q1 and the light emitting element 2a also increases accordingly. Specifically, when comparing the lead line Lt1 provided in the wiring layer Ly1, the lead line Lt2 provided in the wiring layer Ly2, and the lead line Lt3 provided in the wiring layer Ly3, the lead line Lt2 is longer than the lead line Lt1, and the lead line Lt3 is longer than the lead line Lt 2.

In this way, by connecting the driving transistor Q1 on the upper layer to the light emitting element 2a having a short distance, a layout in which the leads Lt do not intersect with each other is easily realized. Therefore, the wiring length can be prevented from becoming longer than necessary to avoid the intersection between the leads Lt, and as a result, the increase in wiring resistance of the leads Lt can be mitigated.

Further, as the length of the lead Lt continuously increases toward the lower layer, the wiring resistance of the lead Lt connecting the light emitting element 2a and the driving transistor Q1 increases. Therefore, there is a problem that power consumption for causing the light emitting element 2a to emit light increases, and a phenomenon such as a temperature rise associated therewith occurs.

Therefore, in the present embodiment, the wiring cross-sectional area SA of the lead Lt is increased in accordance with the wiring length, and by increasing the wiring cross-sectional area SA, an increase in wiring resistance of the lead Lt is alleviated. In a of fig. 16, cross-sectional areas SA1 to SA6 of the leads Lt1 to Lt3 at any positions are shown.

For example, in the lead Lt2, the wiring cross-sectional area SA changes from SA2 to SA3 as the wiring length becomes longer.

At this time, by making the cross-sectional area SA3 have a larger wiring width in the vertical direction (thickness direction) of the wiring layer Ly than the cross-sectional area SA2, a cross-sectional area SA3 having a larger wiring cross-sectional area than the cross-sectional area SA2 is formed.

Similarly, the wiring cross-sectional area SA of the lead Lt3 changes from SA4 to SA5 and SA6 according to the wiring length, and the lead Lt3 having a larger wiring cross-sectional area is formed by continuously increasing the wiring width in the vertical direction (thickness direction) of the wiring layer Ly.

In addition, as described above, with respect to the lead Lt provided in the lower wiring layer Ly, the wiring length is further increased, and as a result, the lead Lt having a larger wiring cross-sectional area SA is formed. For example, the maximum cross-sectional area SA6 of the lead line Lt3 provided in the lower wiring layer Ly3 is larger than the maximum cross-sectional area SA3 of the lead line Lt2 provided in the wiring layer Ly 2.

At this time, in order to enlarge the wiring cross-sectional area SA of the lead Lt, it is also conceivable to provide the lead Lt across a plurality of wiring layers. For example, when the lead line Lt2 provided in the wiring layer Ly2 shown in a of fig. 16 is enlarged from the cross-sectional area SA2 to the cross-sectional area SA3, an unnecessary region in the wiring layer Ly1 may be used. In other words, by forming the lead Lt2 to cross the wiring layer Ly2 and the wiring layer Ly1, the cross-sectional area SA3 can be made larger than the cross-sectional area SA 2.

Similarly, when the lead line Lt3 provided in the wiring layer Ly3 is enlarged from the cross-sectional area SA4 to the cross-sectional area SA5, an unnecessary region in the wiring layer Ly2 may be used in addition to the wiring layer Ly 3. Also, when the lead Lt3 formed across the wiring layer Ly3 and the wiring layer Ly2 is enlarged from the cross-sectional area SA5 to the cross-sectional area SA6, the lead Lt may be formed using an unnecessary region in the wiring layer Ly1 in addition to the wiring layer Ly3 and the wiring layer Ly 2.

In this way, by increasing the wiring cross-sectional area SA by the redundant region of the wiring layer Ly, an increase in wiring resistance of the lead Lt can be alleviated.

Note that, for example, as shown in B of fig. 16, the lead line Lt3 which has been provided in the lower wiring layer Ly3 may also be arranged in the wiring layer Ly1 along the route.

Fig. 17 is a diagram schematically showing chip Ch3 on which chip Ch2 is mounted. As described above, in the driving transistor placement region ar of the chip Ch3, the driving transistors Q1 are provided, and the drain of each driving transistor Q1 is connected to the anode of a corresponding one of the light emitting elements 2a in the light emitting section 2 through the wire Lt.

Note that, although the chip Ch3 is actually formed to have a multilayer structure, of the plurality of wiring layers Ly, only the wiring layer Ly1 is shown in the drawing in order to avoid confusion. Similarly, although the light-emitting section 2 actually includes a plurality of light-emitting elements 2a, the light-emitting element 2a will be described here by taking only three light-emitting elements 2a as an example.

First, in the wiring layer Ly1, a predetermined driving transistor Q1 is connected to a predetermined light emitting element 2a located near the periphery of the chip Ch2 (i.e., the light emitting element 2a spaced apart from the driving transistor Q1 by a short distance) through a wire Lt 4.

In addition, the next driving transistor Q1 provided in the same wiring layer Ly1 is connected to a predetermined light emitting element 2a inside of the light emitting element 2a connected by the wire Lt4 through the wire Lt 5.

Further, the next driving transistor Q1 provided in the same wiring layer Ly1 is connected to a predetermined light emitting element 2a inside of the light emitting element 2a connected by the wire Lt5 through the wire Lt 6.

Thus, when the driving transistor Q1 is connected to the light emitting element 2a via the lead Lt in this order, the distance from the driving transistor Q1 to the light emitting element 2a gradually increases, and the length of the lead Lt to which the driving transistor Q1 is connected to the light emitting element 2a gradually increases. Specifically, when comparing the lead line Lt4, the lead line Lt5, and the lead line Lt6, the lead line Lt5 is longer than the lead line Lt4, and the lead line Lt6 is longer than the lead line Lt5 (and the lead line Lt 4).

In fig. 17, cross-sectional areas SA7 to SA11 of the leads Lt4 to Lt6 at any positions are shown.

For example, in the lead Lt5, the wiring cross-sectional area SA changes from SA8 to SA9 as the wiring length becomes longer.

At this time, by making the cross-sectional area SA9 have a larger wiring width than the cross-sectional area SA8 in the planar direction (planar direction) perpendicular to the perpendicular direction (thickness direction) of the wiring layer Ly, the cross-sectional area SA9 is formed to have a larger wiring cross-sectional area than the cross-sectional area SA 8.

Similarly, the wiring cross-sectional area SA of the lead Lt6 changes from SA10 to SA11 according to the wiring length, and by continuously increasing the wiring width in the plane direction of the wiring layer Ly, the lead Lt6 having a larger wiring cross-sectional area is formed.

Thus, as the wiring length becomes longer, the wiring cross-sectional area SA of the lead Lt becomes larger. For example, the maximum cross-sectional area SA11 of the lead line Lt6 having a longer wiring length than the lead line Lt5 has a larger wiring cross-sectional area than the maximum cross-sectional area SA9 of the lead line Lt 5.

With this configuration, an increase in wiring resistance can be alleviated by increasing the wiring width in the planar direction of the wiring layer Ly.

Note that, in the above, the wiring width in the plane direction of the wiring layer Ly and the wiring width in the thickness direction of the wiring layer Ly are described separately, but the wiring cross-sectional area may be enlarged by increasing the wiring width in the plane direction of the wiring layer Ly and the wiring width in the thickness direction of the wiring layer Ly. By this configuration, a relaxation of an increase in wiring resistance is also obtained.

Next, an example of a lead line Lt electrically connecting the light-emitting element 2a and the driving transistor Q1 will be described with reference to fig. 18.

First, as shown in a of fig. 14, in the case where the driving transistor placement region ar in which the driving transistor Q1 is arranged is provided in a single position with respect to the chip Ch2, the driving transistor Q1 is always connected to the light emitting element 2a (refer to a distance X1 in fig. 18) provided on the opposite side of the chip Ch2 from the driving transistor placement region ar. For this reason, the wiring resistance increases due to the longer lead line Lt, and as a result of increasing the wiring cross-sectional area SA of the lead line Lt to mitigate the increase in the wiring resistance, more space is required to dispose the lead line Lt.

Therefore, as shown in a and 18 of fig. 13, it is conceivable to arrange the driving transistor placement regions ar (ar1 and ar2) at positions facing each other in the chip Ch3 with the chip Ch2 therebetween.

Fig. 18 schematically shows a cross section of chip Ch3 on which chip Ch2 is mounted.

Here, for convenience, an example in which the light emitting section 2 is provided with 6 light emitting elements 2a (2a-1 to 2a-6) will be described. Each of the light emitting elements 2a-1 to 2a-6 provided is not limited to a single light emitting element, and may be formed as a plurality of light emitting elements 2a, for example.

In the present example, the driving transistor Q1 provided in the uppermost wiring layer Ly1 of the driving transistor placement region ar1 is connected to the predetermined light emitting element 2a-1 near the periphery of the chip Ch2 arranged near the driving transistor placement region ar1 side via a wire Lt 1. In addition, as the wiring layers go further to the lower layers Ly2, Ly3, and the like, the driving transistor Q1 is connected to predetermined light emitting elements 2a-2, 2a-3, and the like further inward than the light emitting element 2a connected to the lead Lt in the higher layer, respectively, through the leads Lt2, Lt3, and the like.

At this time, for example, in a case where it is assumed that the driving transistor placement region ar is provided only at a single position as the driving transistor placement region ar1, a new driving transistor Q1 is provided in a wiring layer such as Ly4, Ly5, Ly6, not shown, and is connected to the light emitting elements 2a-4, 2a-5, and 2a-6 through the wiring lines Lt4, Lt5, and Lt6, not shown. In this case, the length of the wire Lt6 joining the light-emitting element 2a-6 farthest from the driving transistor placement region ar1 to the corresponding driving transistor Q1 is a distance X1.

However, in this example, in addition to the driving transistor placement region ar1, a driving transistor placement region ar2 is provided, and like the driving transistor placement region ar1, the driving transistor Q1 is connected in order to the light emitting elements 2a to 6 through the wiring layer Lya, in order to the light emitting elements 2a to 5 through the wiring layer Lyb, and in order to the light emitting elements 2a to 4 through the wiring layer Lyc.

In this case, since the number of light emitting elements 2a connected to the driving transistor Q1 in each driving transistor placement region ar is reduced, the length of the wire Lt3 joining the light emitting element 2a-3 farthest from the driving transistor placement region ar1 to the corresponding driving transistor Q1 is a distance X2, which is shorter than the distance X1 in the case where the driving transistor placement region ar is provided at only a single position. This can shorten the maximum length of the lead line Lt to be provided.

With this configuration, an increase in wiring resistance of the lead line Lt can be alleviated. Further, it is possible to prevent the wiring cross-sectional area SA of the lead Lt from becoming larger than necessary, which is advantageous in designing the wiring in the wiring layer Ly.

<8. summary of examples and modifications >

The light source device (distance measuring device 1) as the above-described embodiment includes the light emitting section 2 in which the light emitting elements 2a of the vertical cavity surface emitting lasers are arrayed, and the driving section 3 configured to cause the plurality of light emitting elements 2a of the light emitting section 2 to emit light, and at least a part of the region (driving transistor placement region ar) including the driving element (driving transistor Q1) in the driving section 3 is arranged so as not to overlap with the light emitting section 2 (see fig. 7, B of fig. 8, fig. 13, and the like).

With this configuration, heat generated from the driving transistor Q1 and transferred to the light emitting element 2a is reduced. In addition, heat generated by the light emitting element 2a and transferred to the drive circuit 30 of the drive section 3 is also reduced.

This can prevent a failure due to heat generated when the temperature of the chip Ch2 (light emitting section 2) forming the light emitting element 2a is likely to increase due to heat generated by a component such as the driver circuit 30(30A) for causing the light emitting element 2a to emit light, and thus prevent the emission efficiency of the light emitting element 2a from being lowered.

In addition, it is also possible to prevent a failure such as deterioration of circuit characteristics of the drive circuit 30(30A) that drives the light emitting element 2a due to heat generated by light emission from the light emitting element 2 a.

Further, in the light source apparatus (distance measuring apparatus 1) as the embodiment, the chip Ch2 formed with the light emitting section 2 is mounted on the chip Ch3 formed with the driving section 3, and at least a part of the region (driving transistor placement region ar) including the driving element (driving transistor Q1) of the driving section 3 is arranged so as not to overlap with the light emitting element 2a of the light emitting section 2 (for example, see fig. 13 and 15).

With this configuration, the lead line Lt connecting the light emitting section 2 and the driving section 3 can be shortened, and an increase in wiring resistance of the lead line Lt can be alleviated. Further, the driving transistor placement region ar may be disposed at a distance from the light emitting element 2a generating heat.

Therefore, when the light emitting element 2a is caused to emit light, phenomena such as an increase in power consumption and a temperature rise associated therewith can be prevented. Further, since the light emitting section 2 is mounted on the driving section 3, the distance between the light emitting element 2a and the driving transistor Q1 is easily shortened. Under such a condition, it is more important not to arrange the driving transistor Q1 to overlap the light emitting element 2a to prevent a heat-induced malfunction.

Further, in the light source apparatus (distance measuring apparatus 1) as an embodiment, the driving section 3 includes a plurality of wiring layers Ly, and a lead line Lt for electrically connecting the driving element (driving transistor Q1) to the light emitting element 2a is formed in the wiring layers Ly (for example, see a of fig. 16 and 18).

With this configuration, it is possible to configure the lead Lt while maintaining the size of the wiring cross-sectional area SA of the lead Lt, and to alleviate an increase in wiring resistance of the lead Lt.

If it is attempted to provide all the leads Lt for connecting hundreds of light emitting elements 2a provided in the chip Ch2 (light emitting section 2) to the driving transistor Q1 in a single wiring layer Ly, it is necessary to reduce the cross-sectional area SA of each lead Lt, so that it is difficult to secure a sufficient cross-sectional area SA to mitigate an increase in wiring resistance of each lead Lt.

Therefore, by adopting the above configuration, the cross-sectional area SA of each lead Lt can be sufficiently ensured, so that phenomena such as an increase in power consumption and a temperature rise associated therewith, which are caused by failure to ensure a sufficiently large cross-sectional area SA of the lead Lt, can be avoided.

Further, in the light source device (distance measuring device 1) as an embodiment, the lead line Lt is formed such that the distance between the driving element (driving transistor Q1) and the light emitting element 2a connected to each other is longer toward the lower layer wiring layer Ly (for example, see a of fig. 16 and 18).

With this arrangement, when the lead line Lt is drawn from a lower layer to an upper layer, it is possible to avoid the situation where the lead line Lt of the lower layer is obstructed by the lead line Lt of the upper layer.

Thus, the length of each lead line Lt can be shortened without complicating the arrangement of the lead lines Lt. Therefore, an increase in wiring resistance of the lead line Lt is alleviated, and phenomena such as an increase in power consumption and a temperature rise associated therewith can be prevented.

Further, in the light source device (distance measuring device 1) as the embodiment, a plurality of regions (driving transistor placement regions ar) including the driving element (driving transistor Q1) are provided in the driving section 3 (see, for example, fig. 13, 14, and 18).

By dividing the driving transistor placement region ar into a plurality of regions in this manner, the length of the lead line Lt connecting the driving transistor Q1 and the light-emitting element 2a can be shortened. Therefore, an increase in wiring resistance of the lead line Lt is alleviated, and phenomena such as an increase in power consumption and a temperature rise associated therewith can be prevented.

Further, in the light source device (distance measuring device 1) as an embodiment, as the length of the lead line Lt becomes longer, portions (for example, SA3, SA5, and SA6 in fig. 16, and SA9 and SA11 in fig. 17) in which the cross-sectional area (wiring cross-sectional area SA) increases when the cross-section is taken in a plane perpendicular to the extending direction of the lead line Lt are formed in the lead line Lt.

Since the wiring Lt becomes longer as the distance between the driving transistor Q1 and the light emitting element 2a increases, the wiring resistance of the wiring Lt increases. Therefore, by increasing the cross-sectional area SA of the lead Lt, an increase in the wiring resistance of the lead Lt is alleviated. Therefore, phenomena such as an increase in power consumption and a temperature rise associated therewith can be prevented.

Further, in the light source apparatus (distance measuring apparatus 1) as an embodiment, in the portion of the lead line Lt (for example, SA3, SA5, and SA6 in fig. 16), the width in the thickness direction of the wiring layer Ly increases.

With this configuration, by increasing the width in the thickness direction of the wiring layer Ly, the cross-sectional area SA of the lead increases, and the increase in wiring resistance is alleviated. Also, by increasing the width in the thickness direction of the wiring layer Ly to mitigate the increase in wiring resistance, a wiring design that leaves an unnecessary space in the plane direction of the wiring layer Ly is possible.

Further, in the light source apparatus (distance measuring apparatus 1) as an embodiment, in the portion of the lead line Lt (for example, SA9 and SA11 in fig. 17), the width in the plane direction of the wiring layer Lt is increased.

With this configuration, by increasing the width of the wiring layer Ly in the plane direction, the cross-sectional area SA of the lead increases, and the increase in wiring resistance is alleviated. Also, by increasing the width of the wiring layer Ly in the plane direction to mitigate the increase in wiring resistance, a wiring design that leaves an unnecessary space in the other wiring layer Ly is possible.

Further, in the light source apparatus (distance measuring apparatus 1) as an embodiment, the cross-sectional area (wiring cross-sectional area SA) of the lead line Lt provided in the wiring layer Ly increases in the wiring layer Ly of the lower layer.

The wiring layer Ly is located at a lower level, and the distance between the driving transistor Q1 and the light emitting element 2a is increased, so that the lead line Lt is increased. Therefore, the wiring resistance of the lead Lt increases. Therefore, by increasing the cross-sectional area SA of the lead Lt, an increase in the wiring resistance of the lead Lt is alleviated. Therefore, phenomena such as an increase in power consumption and a temperature rise associated therewith can be prevented.

Further, in the light source device (distance measuring device 1) as an embodiment, the driving section 3 is configured to be able to drive the light emitting operation individually for each predetermined unit of the plurality of light emitting elements 2a (see fig. 3).

With this configuration, for example, the light emission drive current is set to individually turn on/off the light emission for each light emitting element, or in units of blocks as a plurality of light emitting element groups.

This configuration realizes a configuration that can be controlled according to the temperature condition of each predetermined unit determined as the temperature detection value from each temperature sensor 10 a.

In addition, driving control according to the in-plane temperature distribution of the light emitting section 2 is possible.

With the distance measuring apparatus 1, by controlling the light emitting element 2a of each predetermined unit, exposure with uniform light emission and light energy can be realized, and the brightness of an image of reflected light from a target (object S) appearing in an image captured by the image sensor 7 can be made nearly uniform. By this configuration, the distance measurement sensing accuracy is also improved.

Further, in the light source device (distance measuring device 1) as the embodiment, an example has been described in which the light emitting section 2 emits light in synchronization with the frame period of the image sensor 7, and the image sensor 7 receives the light emitted by the light emitting section 2 and reflected by the object.

With this configuration, in order to deal with a case where a distance is measured by irradiating an object with light emitted by the light emitting section and receiving the light with the image sensor, the light emitting element can be caused to emit light at an appropriate timing according to the frame period of the image sensor.

Therefore, the distance measurement accuracy can be improved. Further, suppression of temperature increase corresponding to a case where the light source device is used as a light source that measures a distance to an object can be obtained.

With the sensing module according to such an embodiment, actions and effects similar to those of the light source device according to the above-described embodiment can also be obtained.

In addition, although an example in which the switch SW is provided for each light emitting element 2a so that the arrangement of each light emitting element 2a can be controlled individually has been described above, in the present technology, the arrangement in which each light emitting element 2a can be driven individually is not necessary, but at least each simultaneous light emitting group can be controlled individually.

In addition, although an example in which the present technology is applied to a distance measuring apparatus is described above, the present technology is not limited to being applied to a light source for distance measurement.

Note that the effects described in this specification are merely non-limiting examples, and other effects may exist.

<9 > the present technology >

Note that the present technology can be configured as follows.

(1) A light source apparatus comprising:

a light emitting section in which light emitting elements of a plurality of vertical cavity surface emitting lasers are arranged; and

a driving section configured to cause the plurality of light emitting elements of the light emitting section to emit light, wherein

At least a part of a region including the driving element in the driving portion is arranged so as not to overlap with the light emitting portion.

(2) The light source device according to (1), wherein

A chip in which a light emitting section is formed is mounted on a chip in which a driving section is formed, and at least a part of a region of the driving section including a driving element is arranged so as not to overlap with the light emitting element of the light emitting section.

(3) The light source device according to (1) or (2), wherein

The driving section includes a plurality of wiring layers in which leads for electrically connecting the driving element and the light emitting element are formed.

(4) The light source device according to (3), wherein

The lead is formed such that the distance between the driving element and the light emitting element connected to each other is longer toward the lower layer of the wiring layer.

(5) The light source device according to (4), wherein

A plurality of regions including a driving element are provided in the driving portion.

(6) The light source device according to any one of (3) to (5), wherein

As the length of the lead increases, a portion in which the cross-sectional area increases greatly when the cross-section is taken in a plane perpendicular to the extending direction of the lead is formed in the lead.

(7) The light source device according to (6), wherein

In the portion of the lead, a width increases in a thickness direction of the wiring layer.

(8) The light source device according to (6) or (7), wherein

In the portion of the lead, a width increases in a planar direction of the wiring layer.

(9) The light source device according to any one of (6) to (8), wherein

The cross-sectional area of the lead provided in the wiring layer is larger toward the lower layer of the wiring layer.

(10) The light source device according to any one of (1) to (9), wherein

The driving section is configured to be capable of individually driving a light emitting operation for each predetermined unit of the plurality of light emitting elements.

(11) The light source device according to any one of (1) to (10), wherein

The light emitting section is configured to emit light in synchronization with a frame period of an image sensor configured to receive the light emitted by the light emitting section and reflected by the object.

(12) A sensing module, comprising:

a light source device provided with a light emitting section in which light emitting elements of a plurality of vertical cavity surface emitting lasers are arrayed, and a driving section configured to cause the plurality of light emitting elements of the light emitting section to be emitted to emit light, wherein at least a part of a region including a switching element in the driving section is arranged so as not to overlap with the light emitting section; and

an image sensor configured to capture an image by receiving light emitted by the light emitting section and reflected by the object.

List of reference numerals

1 distance measuring device

2 light emitting part

2a light emitting element

3. 3A drive part

7 image sensor

10 temperature detecting part

S object

B substrate

Ch2, Ch3, Ch4, Ch34 and Ch7 chips

30. 30A drive circuit

31 drive control part

Q1, Q2 drive transistor

SW switch

100. 100A light source device.