RANGING SYSTEM, DRIVE METHOD, AND ELECTRONIC DEVICE

The present technology relates to a ranging system, a drive method, and an electronic device that are capable of measuring distances to multiple objects at different distances in a single screen. The ranging system includes a lighting device for irradiating, of multiple divided areas obtained by dividing an entire area where irradiation is allowed, two or more divided areas that correspond to some portions of the entire area with irradiation light, and a ranging sensor for receiving reflected light that is the irradiation light reflected from an object. The ranging sensor drives only some portions of an entire light-receiving area that correspond to the two or more divided areas, to receive the reflected light. The present technology is applicable to, for example, ranging modules for measuring distances to objects.

TECHNICAL FIELD

The present technology relates to a ranging system, a drive method, and an electronic device, and in particular, to a ranging system, a drive method, and an electronic device that are capable of measuring distances to multiple objects at different distances in a single screen.

BACKGROUND ART

In recent years, by virtue of advances in semiconductor technology, ranging modules for measuring distances to objects have been reduced in size. With this, for example, mobile devices such as smartphones having ranging modules mounted thereon have been fabricated.

As a ranging method for such ranging modules, for example, the Indirect ToF (Time of Flight) system is available. The Indirect ToF system is a system that irradiates an object with light and that detects the light reflected from a surface of the object to measure the time of flight of the light, to thereby calculate the distance to the object on the basis of the measurement value. As a distance to an object is increased, the light emission intensity of irradiation light with which the object is irradiated needs to be increased. PTL 1 discloses a technology for performing control to change the light amount of a laser light source depending on a distance to be detected.

CITATION LIST

Patent Literature

SUMMARY

Technical Problem

However, in a case where multiple objects are present at different distances in a single screen, since the reflected light amount is different between an object at a long distance and an object at a short distance, it is difficult to acquire the distances to both the objects at the same time.

The present technology has been made in view of such a circumstance and makes it possible to measure distances to multiple objects at different distances in a single screen.

Solution to Problem

According to a first aspect of the present technology, there is provided a ranging system including a lighting device for irradiating, of multiple divided areas obtained by dividing an entire area where irradiation is allowed, two or more divided areas that correspond to some portions of the entire area with irradiation light, and a ranging sensor for receiving reflected light that is the irradiation light reflected from an object. The ranging sensor drives only some portions of an entire light-receiving area that correspond to the two or more divided areas, to receive the reflected light.

According to a second aspect of the present technology, there is provided a drive method for a ranging system including a lighting device and a ranging sensor. The drive method includes irradiating, by the lighting device, of multiple divided areas obtained by dividing an entire area where irradiation is allowed, two or more divided areas that correspond to some portions of the entire area with irradiation light, and driving, by the ranging sensor, only some portions of an entire light-receiving area that correspond to the two or more divided areas, to receive reflected light that is the irradiation light reflected from an object.

According to a third aspect of the present technology, there is provided an electronic device including a ranging system. The ranging system includes a lighting device for irradiating, of multiple divided areas obtained by dividing an entire area where irradiation is allowed, two or more divided areas that correspond to some portions of the entire area with irradiation light, and a ranging sensor for receiving reflected light that is the irradiation light reflected from an object. The ranging sensor drives only some portions of an entire light-receiving area that correspond to the two or more divided areas, to receive the reflected light.

In the first to third aspects of the present technology, the lighting device irradiates, of the multiple divided areas obtained by dividing the entire area where irradiation is allowed, the two or more divided areas that correspond to the some portions of the entire area with irradiation light, and the ranging sensor drives only the some portions of the entire light-receiving area that correspond to the two or more divided areas, to receive the reflected light that is the irradiation light reflected from the object.

The ranging system and the electronic device may be individual devices or may be modules that are incorporated in another device.

DESCRIPTION OF EMBODIMENT

Now, a mode for carrying out the present technology (hereinafter referred to as an “embodiment”) is described with reference to the attached drawings. Note that, in the present specification and the drawings, components having substantially the same functional configurations are denoted by the same reference signs to omit the overlapped description. The following items are described in order.

1. Configuration Example of Ranging System

2. Principle of Indirect ToF Ranging

3. Detailed Configuration Example of Ranging Sensor

4. Configuration Example of Lighting Device

5. Processing Flow of Distance Measurement Processing

6. Configuration Example of Electronic Device

7. Application Example to Mobile Body

<1. Configuration Example of Ranging System>

FIG. 1is a block diagram depicting a configuration example of a ranging system to which the present technology is applied.

A ranging system1inFIG. 1includes a lighting device11, a light emission control section12, a ranging sensor13, and a signal processing section14and performs Indirect ToF ranging.

That is, the ranging system1irradiates a predetermined object15that is an object to be measured, with light (irradiation light), and receives the light reflected from the object15(reflected light). On the basis of the light reception result, the ranging system1then outputs, as measurement results, a confidence map and a depth map that represents information regarding the distance to the object15.

The lighting device11includes, for example, multiple light-emitting elements such as VCSELs (Vertical Cavity Surface Emitting Lasers) arranged in the planar direction.

The lighting device11modulates and emits light at a timing based on a light emission timing signal supplied from the light emission control section12, to irradiate the object15with the irradiation light. The irradiation light is infrared light having a wavelength in a range of approximately 850 to 940 nm, for example.

The lighting device11can turn on and off its irradiation on a divided-area basis. The divided area is obtained by dividing the entire irradiatable area where irradiation can be performed, into multiple divided areas. For example, the lighting device11can perform entire irradiation to irradiate the entire irradiatable area at a uniform light emission intensity in a predetermined luminance range, as depicted in A ofFIG. 2. The lighting device11can also perform partial irradiation to irradiate only one or more divided areas with light, as depicted in B ofFIG. 2. B ofFIG. 2depicts an example in which, of the entire area divided into 5×5=25 divided areas, two divided areas separated from each other are irradiated. In A and B ofFIG. 2, the region indicated by the dot pattern represents an irradiation area. Which divided area is to be irradiated by the lighting device11is controlled with a to-be-illuminated area signal supplied from the light emission control section12.

The light emission control section12supplies a light emission timing signal having a predetermined modulation frequency (for example, 20 or 100 MHz), to the lighting device11, to control the light emission timing of the lighting device11. Further, the light emission control section12supplies the light emission timing signal also to the ranging sensor13to drive the ranging sensor13in synchronization with the light emission timing of the lighting device11.

Moreover, the light emission control section12supplies, to the lighting device11, a to-be-illuminated area signal for controlling the irradiation area of the lighting device11. Further, the light emission control section12supplies the to-be-illuminated area signal also to the ranging sensor13to drive only an area corresponding to the irradiation area of the lighting device11. Thus, the to-be-illuminated area signal also functions as a light-receiving area signal for controlling the light-receiving area of the ranging sensor13, and it can be said that the light emission control section12is a control section for controlling the drive of the entire ranging system1.

The ranging sensor13receives reflected light from the object15by a pixel array section63(FIG. 6) in which multiple pixels are two-dimensionally arranged in a row direction and a column direction, that is, in a matrix. Then, the ranging sensor13supplies a detection signal based on the light amount of the received reflected light, to the signal processing section14pixel by pixel of the pixel array section63.

The signal processing section14calculates, on the basis of the detection signal supplied from the ranging sensor13for each pixel in the pixel array section63, a depth value that is the distance from the ranging system1to the object15. Then, the signal processing section14generates a depth map in which a depth value is stored as a pixel value of each pixel and a confidence map in which a confidence degree is stored as the pixel value of each pixel, and outputs the depth map and the confidence map to the outside. Calculation methods for a depth value and a confidence degree are described later.

Further, the signal processing section14supplies the generated depth map and confidence map also to the light emission control section12. On the basis of the depth map and the confidence map that are supplied from the signal processing section14, the light emission control section12decides an irradiation area, a light emission intensity, and the like, and generates and outputs a to-be-illuminated area signal. The to-be-illuminated area signal includes information regarding the control of light emission, such as irradiation area or light emission intensity information.

The ranging system1configured as described above can control whether or not to perform irradiation with irradiation light, on a divided-area basis. The divided area is obtained by dividing the entire irradiatable area into the multiple divided areas. The ranging sensor13can drive only an area corresponding to a divided area which is irradiated with irradiation light by the lighting device11, to perform reception operation.

For example, in a case where the lighting device11irradiates, as depicted in B ofFIG. 2, only the two divided areas of the entire irradiation area which is divided into the 5×5=25 divided areas, the two divided areas can be irradiated at the same light emission intensity as depicted in A ofFIG. 3, or the two divided areas can be irradiated at different light emission intensities as depicted in B ofFIG. 3. The divided area for which a strong light emission intensity is set corresponds to an object at a long distance from the object15that is a measurement subject, and the divided area for which a weak light emission intensity is set corresponds to an object at a short distance from the object15that is a measurement subject.

Further, as depicted in C ofFIG. 3, on the basis of a to-be-illuminated area signal, the ranging sensor13drives, as a light-receiving area, only an area corresponding to the irradiation area of the lighting device11and supplies the detection signal of each pixel in the light-receiving area to the signal processing section14.

Note that, in the ranging system1, one of the light emission control section12and the signal processing section14can be incorporated in the other as a part thereof, and the light emission control section12and the signal processing section14can be configured as a single signal processing chip.

A ofFIG. 4depicts a chip configuration example in a case where the light emission control section12and the signal processing section14are configured as a single signal processing chip.

For example, the ranging sensor13is formed as a first chip31that is a single chip, and the light emission control section12and the signal processing section14are formed as a second chip32that is a single chip. Further, the first chip31and the second chip32are formed on a relay substrate33, and signals are transferred between the first chip31and the second chip32through the relay substrate33. The relay substrate33has one surface on which the first chip31and the second chip32are mounted, and the opposite surface on which external output terminals such as solder balls are formed.

Further, as depicted in B ofFIG. 4, the ranging sensor13, the light emission control section12, and the signal processing section14may be configured as a single chip.

A single chip35in B ofFIG. 4includes a first die (substrate)36and a second die (substrate)37that are stacked. For example, the first die36includes the ranging sensor13, and the second die37includes the light emission control section12and the signal processing section14.

Note that the single chip35may include three layers including, in addition to the first die36and the second die37, another logic die stacked or include four or more layers of dies (substrates) stacked.

<2. Principle of Indirect ToF Ranging>

Next, with reference toFIG. 5, the principle of Indirect ToF ranging is briefly described.

A depth value d [mm] corresponding to the distance from the ranging system1to the object15can be calculated by the following expression (1).

In the expression (1), At denotes time required for irradiation light to enter the ranging sensor13after being emitted from the lighting device11and then reflected from the object15, and c denotes the speed of light.

As the irradiation light that is emitted from the lighting device11, pulse light in a light emission pattern in which light is repetitively turned on and off at high speed at a predetermined modulation frequency f as depicted inFIG. 5is employed. A single period T in the light emission pattern is 1/f. The ranging sensor13detects reflected light (light reception pattern) in a phase shifted depending on the time Δt required for light to travel from the lighting device11to the ranging sensor13. The time Δt can be calculated by the following expression (2) where φ denotes the phase shift amount (phase difference) between the light emission pattern and the light reception pattern.

Thus, the depth value d from the ranging system1to the object15can be calculated by the following expression (3) according to the expression (1) and the expression (2).

Next, a technique of calculating the phase difference φ described above is described.

Each pixel in the pixel array formed in the ranging sensor13repetitively performs ON/OFF operations at high speed and accumulates charges only in the ON period.

The ranging sensor13sequentially changes the timing of executing the ON/OFF operations in each pixel in the pixel array, accumulates charges at each execution timing, and outputs a detection signal based on the accumulated charges.

The timing of executing the ON/OFF operations includes, for example, four types, namely, a phase of zero degrees, a phase of 90 degrees, a phase of 180 degrees, and a phase of 270 degrees.

The execution timing at the phase of zero degrees is a timing at which the ON timing (light reception timing) of each pixel in the pixel array is in the same phase as the phase of pulse light that the lighting device11emits, that is, the phase of the light emission pattern.

The execution timing at the phase of 90 degrees is a timing at which the ON timing (light reception timing) of each pixel in the pixel array is in a phase delayed by 90 degrees from the phase of pulse light that the lighting device11emits (light emission pattern).

The execution timing at the phase of 180 degrees is a timing at which the ON timing (light reception timing) of each pixel in the pixel array is in a phase delayed by 180 degrees from the phase of pulse light that the lighting device11emits (light emission pattern).

The execution timing at the phase of 270 degrees is a timing at which the ON timing (light reception timing) of each pixel in the pixel array is in a phase delayed by 270 degrees from the phase of pulse light that the lighting device11emits (light emission pattern).

The ranging sensor13sequentially changes the light reception timing in the order of, for example, the phase of zero degrees, the phase of 90 degrees, the phase of 180 degrees, and the phase of 270 degrees and acquires the received light amount (accumulated charges) of reflected light at each light reception timing. InFIG. 5, at the light reception timing (ON timing) in each phase, timings at which reflected light enters are indicated by the diagonal lines.

When, as depicted inFIG. 5, charges accumulated at the light reception timing changed in the order of the phase of zero degrees, the phase of 90 degrees, the phase of 180 degrees, and the phase of 270 degrees are denoted by Q0, Q90, Q180, and Q270, the phase difference φ can be calculated by the following expression (4) using Q0, Q90, Q180, and Q270.

The phase difference φ calculated by the expression (4) can be input to the expression (3) above to calculate the depth value d from the ranging system1to the object15.

Further, a confidence degree conf is a value that indicates the intensity of light received by each pixel, and can be calculated by the following expression (5), for example.

Moreover, a reflectance ref of an object to be measured can be calculated by multiplying the square of the depth value d [mm] and the confidence degree conf as in an expression (6).

When the ranging sensor13includes a single charge accumulation section in each pixel in the pixel array as in the case with a general image sensor, the light reception timing is changed in the order of the phase of zero degrees, the phase of 90 degrees, the phase of 180 degrees, and the phase of 270 degrees by the frame as described above, and detection signals based on accumulated charges (charge Q0, charge Q90, charge Q180, and charge Q270) in the respective phases are sequentially supplied to the signal processing section14. In this case, detection signals for four frames are needed to acquire detection signals in the four phases, namely, the phase of zero degrees, the phase of 90 degrees, the phase of 180 degrees, and the phase of 270 degrees.

In contrast to this, in a case where the ranging sensor13includes two charge accumulation sections in each pixel in the pixel array as described later, charges can be accumulated in the two charge accumulation sections alternately to acquire detection signals at two light reception timings in the opposite phases, such as the phase of zero degrees and the phase of 180 degrees, in a single frame. In this case, detection signals for two frames are only required to acquire detection signals in the four phases, namely, the phase of zero degrees, the phase of 90 degrees, the phase of 180 degrees, and the phase of 270 degrees.

The signal processing section14calculates, on the basis of a detection signal supplied from the ranging sensor13for each pixel in the pixel array, the depth value d that is the distance from the ranging system1to the object15. Then, the signal processing section14generates a depth map in which the depth value d is stored as the pixel value of each pixel and a confidence map in which the confidence degree conf is stored as the pixel value of each pixel, and outputs the depth map and the confidence map to the outside.

<3. Detailed Configuration Example of Ranging Sensor>

FIG. 6is a block diagram depicting a detailed configuration example of the ranging sensor13.

The ranging sensor13includes a timing control section61, a row scanning circuit62, the pixel array section63, multiple AD (Analog to Digital) conversion sections64, a column scanning circuit65, and a signal processing section66. In the pixel array section63, multiple pixels71are two-dimensionally arranged in the row direction and the column direction, that is, in the matrix. Here, the row direction is the arrangement direction of the pixels71in the horizontal direction, and the column direction is the arrangement direction of the pixels71in the vertical direction. The row direction is the horizontal direction inFIG. 6, and the column direction is the vertical direction inFIG. 6.

The timing control section61includes, for example, a timing generator for generating various timing signals. The timing control section61generates various timing signals in synchronization with a light emission timing signal supplied from the light emission control section12(FIG. 1) and supplies the timing signals to the row scanning circuit62, the AD conversion sections64, and the column scanning circuit65. Further, the timing control section61controls, on the basis of a to-be-illuminated area signal supplied from the light emission control section12, the row scanning circuit62, the AD conversion sections64, and the column scanning circuit65to drive only a desired area of the pixel array section63.

The row scanning circuit62includes, for example, a shift register or an address decoder and drives the pixels71in the pixel array section63all at once or row by row, for example. The pixel71receives reflected light under the control of the row scanning circuit62and outputs a detection signal (pixel signal) at a level based on the amount of the received light. The details of the pixel71are described later with reference toFIG. 7.

In the matrix pixel arrangement of the pixel array section63, a pixel drive line72is wired along the horizontal direction in each pixel row, and a vertical signal line73is wired along the vertical direction in each pixel column. The pixel drive line72transmits a drive signal for driving for reading out detection signals from the pixels71. Although the pixel drive line72is depicted as a single wire inFIG. 6, the pixel drive line72includes multiple wires in practice. In a similar manner, although the vertical signal line73is depicted as a single wire, the vertical signal line73includes multiple wires in practice.

The AD conversion section64is provided in each pixel column, for example, and performs, in synchronization with a clock signal CK supplied from the timing control section61, the AD conversion of a detection signal supplied from each of the pixels71in the corresponding pixel column through the vertical signal line73. Under the control of the column scanning circuit65, the AD conversion section64outputs the detection signal (detection data) that has been subjected to the AD conversion, to the signal processing section66. Note that the AD conversion section64may be arranged in each unit of multiple pixel columns instead of being arranged in each single pixel column. The column scanning circuit65selects the AD conversion sections64one by one and causes the AD conversion section64to output detection data that has been subjected to the AD conversion, to the signal processing section66.

The signal processing section66has at least an arithmetic processing function and performs various types of signal processing such as arithmetic processing on the basis of detection data output from the AD conversion sections64.

<Configuration Example of Pixel>

FIG. 7is a block diagram depicting a configuration example of the pixel71.

The pixel71includes a photoelectric conversion element81, a transfer switch82, charge accumulation sections83and84, and selection switches85and86.

The photoelectric conversion element81includes, for example, a photodiode and performs the photoelectric conversion of reflected light to generate charges.

The transfer switch82transfers charges generated by the photoelectric conversion element81, to either the charge accumulation section83or84on the basis of a transfer signal SEL_FD. The transfer switch82includes, for example, a pair of MOS (Metal-Oxide-Semiconductor) transistors.

The charge accumulation sections83and84include, for example, floating diffusion layers. The charge accumulation sections83and84accumulate charges and generate voltages based on the accumulated charges. The charges accumulated in the charge accumulation sections83and84can be reset on the basis of a reset signal RST.

The selection switch85selects the output of the charge accumulation section83on the basis of a selection signal RD_FD1. The selection switch86selects the output of the charge accumulation section84on the basis of a selection signal RD_FD2. That is, when the selection switch85or86is turned on according to the selection signal RD_FD1or RD_FD2, a voltage signal based on the charges accumulated in the charge accumulation section83or84that has been turned on is output to the AD conversion section64as a detection signal through the vertical signal line73. The selection switches85and86each include, for example, a MOS transistor.

The wire for transmitting the transfer signal SEL_FD, the reset signal RST, and the selection signals RD_FD1and RD_FD2corresponds to the pixel drive line72inFIG. 6.

When the charge accumulation section83and the charge accumulation section84are referred to as a “first tap” and a “second tap,” respectively, the pixel71accumulates charges generated by the photoelectric conversion element81, in the first tap and the second tap alternately, for example, so that detection signals at two light reception timings in the opposite phases, such as the phase of zero degrees and the phase of 180 degrees, can be acquired in a single frame. In the next frame, detection signals at two light reception timings in the phase of 90 degrees and the phase of 270 degrees can be acquired.

The ranging sensor13described with reference toFIG. 6, in which the AD conversion section64is arranged in each pixel column, is of a system called the column AD system.

The ranging sensor13can perform reception operation with the light-receiving area divided in association with the 5×5=25 divided areas serving as an irradiation control unit, which are depicted inFIG. 2. Specifically, the pixel array section63that is the entire light-receiving area of the ranging sensor13is divided into 5×5=25 divided areas in association with the irradiation area of the lighting device11.

As depicted inFIG. 8, the rows of the divided areas arranged in the column direction of the pixel array section63are sequentially denoted by 1 to 5, and the columns of the divided areas arranged in the row direction are sequentially denoted by A to E. It is assumed that, as depicted in B ofFIG. 2, the two divided areas, namely, a divided area (2, B) in the area row2and the area column B and a divided area (4, D) in the area row4and the area row D, correspond to the light-receiving area of the pixel array section63that corresponds to the irradiation area of the lighting device11.

In this case, the timing control section61of the column AD ranging sensor13drives the row scanning circuit62such that the pixels71in the respective divided areas in the area row2and the area row4perform reception operation, and drives only the AD conversion sections64corresponding to the pixel columns in the area column B and the area column D. With such partial drive, as compared to a case where the entire light-receiving area of the pixel array section63is driven, the power consumption can be reduced to 2/5, and in a case of the same power consumption, the light emission intensity per divided area can be increased.

As the arrangement method for the AD conversion sections64in the ranging sensor13, other than the column AD system described above, there is a system called the area AD system in which the AD conversion section64is arranged in each unit of M×N pixels (M and N are integers equal to or larger than 1).

FIG. 9depicts a configuration example of the ranging sensor13in a case where the AD conversion sections64are arranged on the basis of the area AD system.

In the case where the AD conversion sections64are arranged on the basis of the area AD system, the ranging sensor13includes, for example, a sensor die101and a logic die102that are stacked. The pixel array section63is formed on the sensor die101, and the multiple AD conversion sections64are formed on the logic die102.

The pixel array section63formed on the sensor die101is divided into L columns and K rows of the pixel blocks111(L and K are integers equal to or larger than 1), and the single pixel block111includes M columns and N rows of the pixels71(M and N are integers equal to or larger than 1).

On the logic die102, the AD conversion sections64equal in number to the pixel blocks111, that is, the L×K AD conversion sections64arranged in L columns and K rows, are formed. On the logic die102, the single AD conversion section64has substantially the same size as the single pixel block111and is placed at a position facing the single pixel block111.

There is a one-to-one correspondence between the AD conversion sections64of the logic die102and the pixel blocks111formed at the same planar positions on the sensor die101, and the AD conversion section64performs the AD conversion of a detection signal output from each of the pixels71in the corresponding pixel block111. Thus, as depicted inFIG. 10, the multiple AD conversion sections64are provided such that the (L×K) pixel blocks111and the (L×K) AD conversion sections64are in a one-to-one correspondence.

Each of the pixels71in the pixel block111formed on the sensor die101inFIG. 9and the AD conversion section64corresponding to the pixel block111are electrically connected to each other by a signal line121. The sensor die101and the logic die102can electrically be connected to each other by, for example, a same metal junction such as a conductor via (VIA), a through-silicon via (TSV), a Cu—Cu junction, an Au—Au junction, or an Al—Al junction, or a different metal junction such as a Cu—Au junction, a Cu—Al junction, or an Au—Al junction.

In a case where such an area ADC ranging sensor13performs reception operation with respect to the 5×5=25 divided areas as depicted inFIG. 2andFIG. 8, for example, the number of the pixel blocks111in each of the vertical direction and horizontal direction is set to five to divide the pixel array section63into the L×K=5×5=25 pixel blocks111.

Further, when the two divided areas, namely, the divided area (2, B) in the area row2and the area column B and the divided area (4, D) in the area row4and the area column D, correspond to the irradiation area of the lighting device11as described with reference toFIG. 8, the timing control section61of the area ADC ranging sensor13drives only the pixel blocks111in the divided area (2, B) and the divided area (4, D) to perform reception operation. With such partial drive, as compared to the case where the entire light-receiving area of the pixel array section63is driven, the power consumption can be reduced to 2/25, and in a case of the same power consumption, the light emission intensity per divided area can be increased.

Further, in a case where the lighting device11irradiates the two divided areas, namely, the divided area (2, B) and the divided area (4, D), sequentially (in a time division manner) instead of irradiating the two divided areas at the same time, and where the ranging sensor13performs reception operation in the divided area (2, B) and the divided area (4, D) sequentially, as compared to the case where the entire light-receiving area of the pixel array section63is driven, the power consumption can be reduced to 1/25, and in a case of the same power consumption, the light emission intensity per divided area can be further increased.

Moreover, M and N can be 1, that is, the single pixel block111can include a single pixel, and the AD conversion section64can be arranged in each pixel. This drive control is called the pixel AD system. In this case, whether or not to perform reception operation can be controlled on a pixel basis instead of an area basis including multiple pixels.

<4. Configuration Example of Lighting Device>

Next, described is a specific configuration example of the lighting device11that is capable of controlling an on-and-off state of irradiation on a divided-area basis. The divided areas are obtained by dividing the entire irradiatable area into multiple areas.

FIG. 11depicts a circuit configuration example of the lighting device11, more specifically, a circuit configuration example corresponding to a predetermined area column which is one of the area columns A to E in the case where the entire irradiatable area of the lighting device11is divided into the 5×5=25 divided areas depicted inFIG. 2.

The lighting device11inFIG. 11includes a DC/DC converter141serving as a power source, a drive section142, and a light-emitting section143.

The drive section142includes a drive control section151, a constant current source161, transistors162and163ato163e, and switches164ato164e. The light-emitting section143includes light-emitting elements165ato165d. The transistors162and163ato163einclude, for example, P channel MOSFETs (MOS: metal-oxide-semiconductor and FET: field-effect transistor). The switches164ato164einclude, for example, N channel MOSFETs. The light-emitting elements165ato165dinclude, for example, VCSELs.

The transistor162has a source connected to an output line of the DC/DC converter141, a drain connected to a ground (GND) through the constant current source161, and a gate connected to the drain. Further, the gate of the transistor162is connected to respective gates of the transistors163ato163ethrough the switches164ato164e.

Sources of the transistors163ato163eare connected to the output line of the DC/DC converter141, drains of the transistors163ato163eare connected to anodes of the corresponding light-emitting elements165ato165d, and the gates of the transistors163ato163eare connected to the gate and drain of the transistor162through the switches164ato164e.

The DC/DC converter141converts a DC input voltage Vin to an output voltage Vd and supplies the output voltage Vd to the sources of the transistors162and163ato163e.

The drive control section151turns on and off the switches164ato164eon the basis of a light emission timing signal and a to-be-illuminated area signal that are supplied from the light emission control section12(FIG. 1). Specifically, the drive control section151turns on the switches164ato164ecorresponding to divided areas for which a light emission timing signal of High and a to-be-illuminated area signal indicating irradiation are given.

In a case where the switches164ato164eare turned on, the constant current source161and the transistors162and163ato163eform a current mirror circuit, so that a current Id that is the same as a current Id flowing through the transistor162flows through the transistors163ato163eand is also supplied to the light-emitting elements165ato165das a drive current Id. As a result, the light-emitting elements165ato165demit light.

In a case where the switches164ato164eare turned off, the drive current Id does not flow through the light-emitting elements165ato165d, so that the light-emitting elements165ato165ddo not emit light.

The lighting device11includes the circuit depicted inFIG. 11, in each of the area columns A to E in the 5×5=25 divided areas depicted inFIG. 8, for example.

In the circuit configuration inFIG. 11, the same drive current Id flows through the light-emitting elements165ato165din the case where the switches164ato164eare controlled to be turned on. Therefore, in a case where the light emission intensity is changed in each divided area, the light emission period integration time (total time) is changed. That is, in a case where the light emission intensity is to be increased, the light emission period integration time is controlled to be lengthened, and in a case where the light emission intensity is to be reduced, the light emission period integration time is controlled to be shortened.

Besides, as a control method performed in a case where the light emission intensity is changed in each divided area, there can be employed a method that varies, with the divided areas having the same light emission period integration time, the output voltage Vd of the DC/DC converter141to make the drive current Id that flows through the light-emitting elements165ato165ddifferent.

FIG. 12is a sectional view depicting a substrate structure example of the light-emitting section143of the lighting device11.

InFIG. 12, on a chip Ch1having a drive circuit formed thereon, a chip Ch2having the light-emitting elements165ato165dformed thereon is mounted.

In the chip Ch2, on the front side (lower side inFIG. 12) of a semiconductor substrate201, five mesas M corresponding to the light-emitting elements165are arranged in the planar direction. The semiconductor substrate201is used as a substrate of the chip Ch2, and as the semiconductor substrate201, for example, a GaAs (gallium arsenide) substrate is used. InFIG. 12, the light-emitting elements165each have a back-illuminated cross-sectional structure that emits light toward a back surface of the semiconductor substrate201, and a cathode electrode Tc is formed on the back side, which is the upper side inFIG. 12, of the semiconductor substrate201.

In each of the mesas M on the front side of the semiconductor substrate201, in order from the upper layer side to the lower layer side, a first multilayer reflective mirror layer221, an active layer222, a second multilayer reflective mirror layer225, a contact layer226, and an anode electrode Ta are formed.

A current confining layer224is formed in part of the second multilayer reflective mirror layer225. Further, a portion that includes the active layer222and is sandwiched between the first multilayer reflective mirror layer221and the second multilayer reflective mirror layer225serves as a resonator223.

The first multilayer reflective mirror layer221includes an N-type conductivity compound semiconductor, and the second multilayer reflective mirror layer225includes an N-type conductivity compound semiconductor.

The active layer222is a layer for generating laser light, and the current confining layer224is a layer for efficiently injecting a current into the active layer222and providing the lens effect.

The current confining layer224which is not oxidized is subjected to selective oxidation after the formation of the mesas M, and thus have a central oxidized region (or selectively oxidized region)224aand a non-oxidized region224bwhich is not oxidized and which surrounds the oxidized region224a. In the current confining layer224, the oxidized region224aand the non-oxidized region224bform a current confining structure, and a current flows through a current confining region that is the non-oxidized region224b.

The contact layer226is provided for enhancing the ohmic contact with the anode electrode Ta.

The light-emitting elements165each have a pad Pa for an electrical connection with the anode electrode Ta. In the wiring layer of the chip Ch1, a wire Ld is formed for each of the pads Pa. Although not depicted, by the wire Ld, each of the pads Pa is connected to the drain of the corresponding transistor163in the chip Ch1.

Further, in the chip Ch2, the cathode electrode Tc is connected to an electrode Tc1through a wire Lc1and to an electrode Tc2through a wire Lc2. The electrode Tc1is connected to a pad Pc1formed on the chip Ch1through a solder bump Hb, and the electrode Tc2is connected to a pad Pc2formed on the chip Ch1through the solder bump Hb.

In the wiring layer of the chip Ch1, a ground wire Lg1connected to the pad Pc1and a ground wire Lg2connected to the pad Pc2are formed. Although not depicted, the ground wires Lg1and Lg2are connected to the ground.

Although the substrate structure example of the lighting device11depicted inFIG. 12is a back-illuminated example that emits light from the back side of the semiconductor substrate201, a front-illuminated structure can also be used. In this case, the contact layer226toward which light is emitted is formed into a shape with an opening formed at the central part thereof in plan view, such as an annular (ring) shape, that is, has an opening. Light generated by the active layer222oscillates back and forth in the resonator223and is then emitted to the outside through the opening portion.

On the upper side of the mesas M toward which the light-emitting elements165ato165demit light, projection lenses241ato241eare arranged for the respective mesas M. The projection lens241irradiates the corresponding area with infrared light emitted from the mesa M located under the projection lens241. For example, in a case where the projection lenses241ato241einFIG. 12correspond to the area column B in the 5×5=25 divided areas depicted inFIG. 8, the projection lens241airradiates the divided area (1, B) with infrared light, the projection lens241birradiates the divided area (2, B) with infrared light, the projection lens241cirradiates the divided area (3, B) with infrared light, the projection lens241dirradiates the divided area (4, B) with infrared light, and the projection lens241eirradiates the divided area (5, B) with infrared light.

FIG. 12is the example of the case where the light-emitting elements165and the divided areas are in a one-to-one correspondence and where the light-emitting elements165are the same in light distribution characteristics, but the light-emitting elements165may be different from each other in light distribution characteristics as depicted inFIG. 13.

For example, the light-emitting elements165can also have the following light distribution characteristics: in a case where a single light-emitting element165emits light, only an area261of all the 5×5=25 divided areas that is indicated by the diagonal lines inFIG. 14is irradiated with infrared light, in a case where another single light-emitting element165emits light, only a central 3×3 area262indicated by the dots inFIG. 14is irradiated with infrared light, and in a case where still another single light-emitting element165emits light, a 5×5 area263that is the entire area is irradiated with infrared light.

With such a combination of the light-emitting elements165and the to-be-illuminated areas, the number of the light-emitting elements165can be smaller than the number of divided areas.

On the other hand, with the light-emitting elements165greater in number than the divided areas, finer light emission control may be performed.

For example, as depicted inFIG. 15, a light-emitting unit282including three light-emitting elements281ato281ccan be provided in each of the 5×5=25 divided areas depicted inFIG. 8, and irradiation angles can be made different depending on which of the light-emitting elements281ato281cis caused to emit light.

<5. Processing Flow of Distance Measurement Processing>

Next, with reference to the flowchart ofFIG. 16, distance measurement processing by which the ranging system1inFIG. 1measures the distance to the object15that is an object to be measured is described.

This processing starts when a distance measurement start instruction is supplied from a control section of a host device in which the ranging system1is incorporated, for example.

First, in Step S1, the light emission control section12supplies, to the lighting device11and the ranging sensor13, a light emission timing signal and a to-be-illuminated area signal which indicates that an area to be illuminated is the entire irradiatable area of the lighting device11.

In Step S2, the lighting device11irradiates, on the basis of the to-be-illuminated area signal and the light emission timing signal, the entire irradiatable area of the lighting device11that is the irradiation area, with irradiation light.

In Step S3, the ranging sensor13drives, on the basis of the to-be-illuminated area signal and the light emission timing signal, the entire area of the pixel array section63as a light-receiving area and receives the reflected light. The ranging sensor13supplies a detection signal based on the light amount of the received reflected light, to the signal processing section14pixel by pixel of the pixel array section63.

In Step S4, the signal processing section14calculates, on the basis of the detection signal supplied from the ranging sensor13for each pixel71in the pixel array section63, a depth value that is the distance from the ranging system1to the object15. Then, the signal processing section14generates a depth map in which the depth value is stored as the pixel value of each of the pixels71and a confidence map in which a confidence degree is stored as the pixel value of each of the pixels71, and outputs the depth map and the confidence map to the light emission control section12and the outside.

In Step S5, the light emission control section12uses the depth map and the confidence map that are supplied from the signal processing section14, to decide one or more divided areas to be irradiated next, decide irradiation conditions and exposure conditions (light reception conditions), and generate a to-be-illuminated area signal and a light emission timing signal.

Specifically, first, the light emission control section12decides one or more divided areas to be irradiated next. In the following, divided areas for the lighting device11that have been decided to be irradiated next and portions of the light-receiving area of the pixel array section63that correspond to the divided areas are also collectively referred to as a “drive area.” The drive area can be decided by identifying a light-receiving area with the use of a depth map and a confidence map, as described below.

For example, the light emission control section12uses a depth map and a confidence map to detect, as an area of interest, a face region of a person who is an object, a body region of a person who is an object, a region in which a moving object that is an object is present, a gaze region at which a person who is an object gazes, a saliency region in which a person is interested, or other regions. Thus, the light emission control section12can decide the detected area of interest as a light-receiving area. Alternatively, the light emission control section12may acquire a user specified region that is specified by the user, as an area of interest from the outside (host control section) and may then decide the user specified region as a light-receiving area. With the use of any other region detection techniques, a region having unique features in the maps can be detected as an area of interest and decided as a light-receiving area.

Then, the light emission control section12decides irradiation conditions and exposure conditions (light reception conditions) for each of the one or more drive areas.

The irradiation conditions for a drive area include, for example, the modulation frequency, the light emission period integration time, the Duty ratio indicating the ratio between the ON period and the OFF period of light emission in a single period, or the light emission intensity indicating the intensity of irradiation light. Those irradiation conditions can be set to different values between drive areas.

Meanwhile, the exposure conditions for a drive area include the frame rate, the exposure period integration time, the light sensitivity, or the like. The frame rate and the exposure period integration time correspond to the modulation frequency on the light emission side, the exposure period integration time corresponds to the light emission period integration time on the light emission side, and the light sensitivity corresponds to the light emission intensity on the light emission side. The light sensitivity can be changed as follows: in a case where the charge accumulation sections83and84of the pixel71each include two floating diffusion layers connected to each other in parallel through a switching MOS transistor, the connection and disconnection between the two floating diffusion layers is controlled by the MOS transistor to increase or decrease the storage capacitance, thereby changing the conversion efficiencies of the charge accumulation sections83and84in converting the accumulated charges to a voltage.

The irradiation conditions and exposure conditions for each drive area can be decided depending on the distance (depth value d) to an object, the reflectance ref of the object, the motion amount of the object, or the like.

In the end of Step S5, the light emission control section12generates a to-be-illuminated area signal and a light emission timing signal corresponding to the one or more divided areas that have been decided and the irradiation conditions and exposure conditions that have been decided, and supplies the to-be-illuminated area signal and the light emission timing signal to the lighting device11and the ranging sensor13.

In Step S6, the lighting device11controls, on the basis of the light emission timing signal and the to-be-illuminated area signal that are supplied from the light emission control section12, only some of the light-emitting elements165to emit light, thereby performing partial irradiation with the irradiation light.

In Step S7, the ranging sensor13drives, on the basis of the light emission timing signal and the to-be-illuminated area signal that are supplied from the light emission control section12, only some portions of the light-receiving area of the pixel array section63to perform partial exposure with the reflected light from the object15. The ranging sensor13supplies a detection signal based on the light amount of the reflected light received in the driven portions of the light-receiving area, to the signal processing section14pixel by pixel of the pixel array section63.

The light emission by the lighting device11in Step S6and the light reception by the ranging sensor13are partial irradiation and partial exposure in which only some of the multiple divided areas obtained by dividing the entire area are driven.

In Step S8, the signal processing section14generates, on the basis of the detection signal of each pixel in the portions of the light-receiving area supplied from the ranging sensor13, a depth map and a confidence map and outputs the depth map and the confidence map to the light emission control section12and the outside.

In Step S9, the light emission control section12calculates the motion amount of the object included in the light-receiving area, on the basis of the depth map and the confidence map that are supplied from the signal processing section14and a depth map and a confidence map in the previous frame. Then, the light emission control section12determines, on the basis of the calculated motion amount, whether the object is going to get out of the driven portions of the light-receiving area.

In a case where it is determined in Step S9that the object is going to get out of the driven portions of the light-receiving area, the processing returns to Step S1, and Steps S1to S9described above are repeated. That is, the ranging system1executes light emission and light reception with respect to the entire area to identify a light-receiving area over again.

On the other hand, in a case where it is determined in Step S9that the object is not going to get out of the driven portions of the light-receiving area, the processing proceeds to Step S10, and the light emission control section12determines whether an interval period has elapsed. The interval period is a time interval in which light emission and light reception with respect to the entire area are executed, and can be set in advance on a setting screen.

In a case where it is determined in Step S10that the interval period has not elapsed yet, the processing returns to Step S6, and Steps S6to S10described above are repeated. That is, partial irradiation and partial exposure are continuously executed.

On the other hand, in a case where it is determined in Step S10that the interval period has elapsed, the processing returns to Step S1, and Steps S1to S9described above are executed. With this, light emission and light reception with respect to the entire area are executed again to identify a light-receiving area over again.

The processing in Steps S1to S10described above is continuously executed until a distance measurement end instruction is supplied from the control section of the host device, for example, and ends when the distance measurement end instruction is supplied. Alternatively, the distance measurement processing may end when the object gets out of the entire area of the lighting device11.

As described above, with the distance measurement processing that is executed by the ranging system1, the lighting device11can perform partial irradiation to irradiate only some portions of the entire irradiatable area, and the irradiation area in partial irradiation can include multiple divided areas separated from each other. Further, the irradiation area in partial irradiation can adaptively be changed depending on an area of interest. The ranging sensor13can drive, in the distance measurement processing, only some portions corresponding to an irradiation area in partial irradiation, to receive light.

With the lighting device11for performing partial irradiation, the power consumption of the lighting device11can be reduced, and the measurement accuracy can also be improved by virtue of the increased light emission intensity with a narrowed irradiation area.

With the ranging sensor13for driving some portions corresponding to an irradiation area in partial irradiation, the power consumption of the ranging sensor13can be reduced, and signals can be read out at high speed with a narrowed signal read-out area.

Further, since the lighting device11can individually adjust the light emission intensity for each of multiple divided areas to be set to an irradiation area, a strong light emission intensity can be set for an object at a long distance that is present in a first divided area, and a weak light emission intensity can be set for an object at a short distance that is present in a second divided area. Therefore, the distances to the multiple objects at different distances can be measured in a single screen.

<6. Configuration Example of Electronic Device>

The ranging system1described above can be mounted on an electronic device such as a smartphone, a tablet device, a cell phone, a personal computer, a game console, a television receiver, a wearable device, a digital still camera, or a digital video camera.

FIG. 17is a block diagram depicting a configuration example of a smartphone that is an electronic device having the ranging system1mounted thereon.

As depicted inFIG. 17, a smartphone601includes a ranging module602, an imaging device603, a display604, a speaker605, a microphone606, a communication module607, a sensor unit608, a touch panel609, and a control unit610that are connected to each other through a bus611. Further, the control unit610functions, by running programs by the CPU, as an application processing section621and an operation system processing section622.

The ranging system1inFIG. 1that has been modularized is applied as the ranging module602. For example, the ranging module602is placed on a front surface of the smartphone601. The ranging module602can perform ranging with respect to a user of the smartphone601and output, as a ranging result, the depth value of the surface shape of the face, hands, fingers, or the like of the user.

The imaging device603is placed on the front surface of the smartphone601and images the user of the smartphone601as a subject to acquire the image of the user. Note that, although not depicted, the imaging device603may also be placed on a back surface of the smartphone601.

The display604displays an operation screen for performing processing by the application processing section621and the operation system processing section622, and displays an image captured by the imaging device603, for example. In a call with the smartphone601, the speaker605outputs the voice of a party on the other side, and the microphone606collects the voice of the user, for example.

The communication module607performs communication via a communication network. The sensor unit608senses speed, acceleration, proximity, or the like, and the touch panel609acquires a touch operation performed by the user on the operation screen displayed on the display604.

The application processing section621performs processing for providing various services by the smartphone601. For example, the application processing section621can perform processing of generating, on the basis of the depth supplied from the ranging module602, a face by virtually reproducing the facial expressions of the user with the use of computer graphics and displaying the generated face on the display604. Further, the application processing section621can perform processing of generating three-dimensional shape data of any three-dimensional object on the basis of the depth supplied from the ranging module602, for example.

The operation system processing section622performs processing for realizing the basic functions and actions of the smartphone601. For example, the operation system processing section622can perform processing of identifying the face of the user on the basis of a depth value supplied from the ranging module602, to unlock the smartphone601. Further, the operation system processing section622can perform processing of recognizing, for example, the user's gesture on the basis of a depth value supplied from the ranging module602, to receive various operations based on the gesture as input.

With the application of the ranging system1described above, the smartphone601configured in such a manner can calculate, for example, ranging information regarding different objects at a long distance and a short distance. With this, the smartphone601can more accurately detect ranging information.

<7. Application Example to Mobile Body>

The technology according to the present disclosure (present technology) is applicable to various products. For example, the technology according to the present disclosure may be realized as a device that is mounted on any type of a mobile body such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, a personal mobility, an airplane, a drone, a ship, or a robot.

FIG. 19is a diagram depicting an example of the installation position of the imaging section12031.

An example of the vehicle control system to which the technology according to the present disclosure is applicable has been described above. The technology according to the present disclosure is applicable to the outside-vehicle information detecting unit12030or the in-vehicle information detecting unit12040among the above-mentioned configurations. Specifically, through ranging by the ranging system1serving as the outside-vehicle information detecting unit12030or the in-vehicle information detecting unit12040, processing of recognizing the driver's gesture can be performed to execute various (for example, audio system, navigation system, or air conditioning system) operations based on the gesture or more accurately detect the driver's conditions. Further, through ranging by the ranging system1, the irregularities of the road surface can be recognized to be reflected in the control of the suspension.

The embodiment of the present technology is not limited to the embodiment described above, and various modifications can be made within the scope of the gist of the present technology.

The multiple present technologies described herein can be implemented independently of each other as long as no contradiction arises. Needless to say, the multiple present technologies can be implemented in any combination. Further, part or whole of any of the present technologies described above can be implemented in combination with another technology not described above.

Further, for example, the configuration described as a single device (or processing unit) may be divided into multiple devices (or processing units). In contrast, the configurations described above as multiple devices (or processing units) may be put into a single device (or processing unit). In addition, needless to say, a configuration other than the ones described above may be added to the configuration of each device (or each processing unit). Moreover, as long as the configuration and operation of the entire system is substantially unchanged, the configuration of a certain device (or processing unit) may be partially included in the configuration of another device (or another processing unit).

Furthermore, herein, a “system” means an aggregation of multiple components (devices, modules (parts), or the like), and it does not matter whether or not all the components are in the same cabinet. Thus, multiple devices that are accommodated in separate cabinets and that are connected to each other via a network and a single device including multiple modules accommodated in a single cabinet are both “systems.”

Note that the effects described herein are merely exemplary and are not limited to them, and effects other than the ones described herein may be provided.

Note that the present technology can also take the following configurations.

A ranging system including:

a lighting device for irradiating, of multiple divided areas obtained by dividing an entire area where irradiation is allowed, two or more divided areas that correspond to some portions of the entire area with irradiation light; and

a ranging sensor for receiving reflected light that is the irradiation light reflected from an object,

in which the ranging sensor drives only some portions of an entire light-receiving area that correspond to the two or more divided areas, to receive the reflected light.

The ranging system according to (1), in which at least two divided areas irradiated with irradiation light by the lighting device are different from each other in light emission intensity.

The ranging system according to (1) or (2), in which at least two divided areas irradiated with irradiation light by the lighting device are different from each other in modulation frequency.

The ranging system according to any one of (1) to (3), in which at least two divided areas irradiated with irradiation light by the lighting device are different from each other in light emission period integration time.

The ranging system according to any one of (1) to (4), in which at least two divided areas irradiated with irradiation light by the lighting device are different from each other in ratio between an on-period and an off-period of a light emission period.

The ranging system according to any one of (1) to (5), in which two portions of the light-receiving area of the ranging sensor that correspond to two or more divided areas irradiated with irradiation light by the lighting device are different from each other in frame rate.

The ranging system according to any one of (1) to (6), in which two portions of the light-receiving area of the ranging sensor that correspond to two or more divided areas irradiated with irradiation light by the lighting device are different from each other in exposure period integration time.

The ranging system according to any one of (1) to (7), in which two portions of the light-receiving area of the ranging sensor that correspond to two or more divided areas irradiated with irradiation light by the lighting device are different from each other in light sensitivity.

The ranging system according to any one of (1) to (8), in which the ranging sensor includes, in each of one or more pixel columns, an AD conversion section for performing AD conversion of a detection signal that is output from a pixel according to the reflected light.

The ranging system according to any one of (1) to (8), in which the ranging sensor includes, in each unit of M×N pixels (M and N are integers equal to or larger than 1) arranged in M rows and N columns, an AD conversion section for performing AD conversion of a detection signal that is output from a pixel according to the reflected light.

The ranging system according to any one of (1) to (10), in which the lighting device includes multiple light-emitting elements, and the multiple light-emitting elements are the same in light distribution characteristic.

The ranging system according to any one of (1) to (11), in which the lighting device includes multiple light-emitting elements, and the multiple light-emitting elements are different from each other in light distribution characteristic.

The ranging system according to any one of (1) to (12), further including:

a control section for controlling the two or more divided areas that are irradiated with irradiation light by the lighting device and the some portions of the light-receiving area that correspond to the two or more divided areas.

The ranging system according to (13), in which the control section decides the two or more divided areas that are to be irradiated and the some portions of the light-receiving area that correspond to the two or more divided areas, on the basis of a light reception result obtained when the lighting device irradiates the entire area with irradiation light and the ranging sensor receives the irradiation light in the entire light-receiving area.

The ranging system according to (14), in which the control section decides an area of interest on the basis of a light reception result obtained when the lighting device irradiates the entire area with irradiation light and the ranging sensor receives the irradiation light in the entire light-receiving area, to thereby decide the two or more divided areas and the some portions of the light-receiving area that correspond to the area of interest.

The ranging system according to (15), in which the area of interest includes any of a face region of a person, a body region of the person, a region in which a moving object is present, a gaze region of the person, a saliency region, or a user specified region.

The ranging system according to any one of (14) to (16), in which the control section decides the two or more divided areas that are to be illuminated and the some portions of the light-receiving area that correspond to the two or more divided areas, on the basis of a depth map and a confidence map obtained when the lighting device irradiates the entire area with irradiation light and the ranging sensor receives the irradiation light in the entire light-receiving area.

A drive method for a ranging system including a lighting device and a ranging sensor, the drive method including:

irradiating, by the lighting device, of multiple divided areas obtained by dividing an entire area where irradiation is allowed, two or more divided areas that correspond to some portions of the entire area with irradiation light; and

driving, by the ranging sensor, only some portions of an entire light-receiving area that correspond to the two or more divided areas, to receive reflected light that is the irradiation light reflected from an object.

An electronic device including:

a ranging system includinga lighting device for irradiating, of multiple divided areas obtained by dividing an entire area where irradiation is allowed, two or more divided areas that correspond to some portions of the entire area with irradiation light, anda ranging sensor for receiving reflected light that is the irradiation light reflected from an object,

the ranging sensor being configured to drive only some portions of an entire light-receiving area that correspond to the two or more divided areas, to receive the reflected light.

REFERENCE SIGNS LIST