Patent Description:
In recent years, various sensor devices such as light detection and ranging (LiDAR) have been developed. A sensor device includes a movable reflection unit such as a micro-electro-mechanical systems (MEMS) mirror. The sensor device scans a target object such as an object existing outside the sensor device by reflecting electromagnetic waves such as infrared radiation toward a predetermined scanning range by the movable reflection unit.

<CIT> describes placing a reflection member at one end of a scanning range of a movable reflection unit in order to find a direction in which laser light reflected by the movable reflection unit is output. The laser light reflected by the reflection member is received by a light receiving unit. Based on the receiving result by the light receiving unit, the distance from the movable reflection unit to the reflection member is calculated. Based on the distance from the movable reflection unit to the reflection member, the direction in which the laser light reflected by the movable reflection unit is output is calculated.

<CIT> describes providing a reflection member on a housing accommodating members constituting a sensor device, such as a movable reflection unit, and detecting a deviation of a scanning position of the movable reflection unit with laser light reflected by the reflection member.

<CIT> discloses an emission timing controller comprising: a storage part for storing the relation between a mirror angle of a rotary-reciprocating mirror for deflecting a laser beam and an emission angle of the laser beam from a scan-angle-enlarging lens for enlarging a scan angle of the laser beam deflected by the mirror using mirror angles represented by lapsed times from a reference position of the mirror; a detector for detecting the reference position based on an output signal of a sensor which detects a mirror angle; a measurement part for measuring a time based on the reference position detected by the detector; and a controller for driving a laser source to emit a laser beam when the measured time by the measurement part coincides with the lapsed time stored in the storage part and for correcting driving timing based on a mirror angular amplitude. <CIT> discloses an image display device comprising: a first scanner and a second scanner for scanning a light beam emitted from a light source; a half mirror provided on a light path between the first scanner and the second scanner; a light detector for detecting the intensity and timing of the incident light beam scanned by the first scanner and reflected by the half mirror; a first reflector and a second reflector arranged at an image plane position formed by the light beam scanned by the second scanner for reflecting the light beam scanned by the second scanner; and an optical member for bringing the light path of the incident light beam scanned by the first scanner, reflected by each of the first reflector and the second reflector, and reflected by the half mirror to enter the light detector to the same light path as the light path of the light beam scanned by the first scanner and reflected by the half mirror. <CIT> discloses a method of correcting angular drift of a laser radar system, the method comprising: providing a plurality of virtual fiducials targets into an xy scanner; providing a plurality of auxiliary laser sources into the xy scanner; routing a plurality of auxiliary laser beams from the plurality of auxiliary laser sources into the xy scanner; and calibrating an angular position of a plurality of laser directing means.

A sensor device may be provided with a detection unit for detecting a deflection angle of a movable reflection unit. However, the sensitivity of the detection unit may have temperature dependence. In this case, a detection result by the detection unit may deviate from a detection result in a design state.

Examples of a problem to be solved by the present invention include amending a deviation of a detection result of a deflection angle of a movable reflection unit by a detection unit from a detection result in a design state.

The invention according to claim <NUM> is a sensor device including:.

An embodiment of the present invention will be described below by using drawings. Note that, in every drawing, similar components are given similar signs, and description thereof is omitted as appropriate.

<FIG> is a diagram illustrating a sensor device <NUM> according to the embodiment.

In <FIG>, a first direction X and a second direction Y intersect each other and specifically are orthogonal to each other. In <FIG>, the first direction X is a horizontal direction. A positive direction of the first direction X being a direction of an arrow indicating the first direction X is leftward viewed from a movable reflection unit <NUM> to be described later toward a scanning range, to be described later, of the movable reflection unit <NUM>. A negative direction of the first direction X being a direction opposite to the direction of the arrow indicating the first direction X is rightward viewed from a side on which the movable reflection unit <NUM> is positioned toward the scanning range of the movable reflection unit <NUM>. The second direction Y is a vertical direction. A positive direction of the second direction Y being a direction of an arrow indicating the second direction Y is upward. A negative direction of the second direction Y being a direction opposite to the direction of the arrow indicating the second direction Y is downward.

As is obvious from the description herein, the first direction X may be a direction different from the horizontal direction, and the second direction Y may be a direction different from the vertical direction.

The sensor device <NUM> includes an emission unit <NUM>, the movable reflection unit <NUM>, a detection unit <NUM>, a receiving unit <NUM>, a beam splitter <NUM>, an amendment unit <NUM>, a first adjustment unit <NUM>, and a second adjustment unit <NUM>. In <FIG>, a dotted line extending over the emission unit <NUM>, the movable reflection unit <NUM>, the receiving unit <NUM>, the beam splitter <NUM>, and a scanning line L indicates electromagnetic waves propagating over the emission unit <NUM>, the movable reflection unit <NUM>, the receiving unit <NUM>, the beam splitter <NUM>, and the scanning line L. In <FIG>, the electromagnetic waves reflected from the movable reflection unit <NUM> toward the scanning line L are projected toward a roughly central part of a region where the scanning line L is formed.

The emission unit <NUM> emits electromagnetic waves such as pulse-shaped infrared radiation a certain time intervals. For example, the emission unit <NUM> is an element, such as a laser diode (LD), that can convert electricity such as current into electromagnetic waves such as light. The electromagnetic waves emitted from the emission unit <NUM> are reflected by the beam splitter <NUM> and enters the movable reflection unit <NUM>.

The movable reflection unit <NUM> reflects electromagnetic waves emitted from the emission unit <NUM> toward inside a predetermined scanning range. The scanning range of the movable reflection unit <NUM> is a range on which the electromagnetic waves reflected by the movable reflection unit <NUM> can be projected. For example, the movable reflection unit <NUM> is a biaxial MEMS mirror. For example, the movable reflection unit <NUM> is sinusoidally driven along the first direction X and is driven in a sawtooth wave shape along the second direction Y at a frequency lower than that of the sinusoidal wave along the first direction X. In other words, the first direction X is a resonance drive direction of the movable reflection unit <NUM>, and the second direction Y is a linear drive direction of the movable reflection unit <NUM>.

The detection unit <NUM> detects deflection angles of the movable reflection unit <NUM> in the first direction X and the second direction Y. For example, the detection unit <NUM> is a piezoresistor provided on the movable reflection unit <NUM>. The deflection angles of the movable reflection unit <NUM> in the first direction X and the second direction Y are controlled based on a detection result by the detection unit <NUM>. Accordingly, when the sensitivity of the detection unit <NUM> has temperature dependence, the detection result of the deflection angles of the movable reflection unit <NUM> by the detection unit <NUM> may vary according to the temperature, and as a result, the deflection angles of the movable reflection unit <NUM> may vary according to the temperature. As will be described later, a detection result of the deflection angles of the movable reflection unit <NUM> by the detection unit <NUM> can be amended by the amendment unit <NUM>, according to the present embodiment.

Some of electromagnetic waves being emitted from the emission unit <NUM> and being reflected by the movable reflection unit <NUM> are reflected or scattered by a target object such as an object existing outside the sensor device <NUM>. The electromagnetic waves return to the movable reflection unit <NUM>, enter the receiving unit <NUM> after sequentially undergoing reflection by the movable reflection unit <NUM> and transmission by the beam splitter <NUM>, and are received by the receiving unit <NUM>. For example, the receiving unit <NUM> is an element, such as an avalanche photodiode (APD), that can convert electromagnetic waves such as light into an electric signal such as current.

Some other of the electromagnetic waves being emitted from the emission unit <NUM> and being reflected by the movable reflection unit <NUM> are reflected or scattered by a structure <NUM> positioned closer to the movable reflection unit <NUM> than the target object is. The electromagnetic waves return toward the movable reflection unit <NUM>, enter the receiving unit <NUM> after sequentially undergoing reflection by the movable reflection unit <NUM> and transmission by the beam splitter <NUM>, and are received by the receiving unit <NUM>. Examples of the structure <NUM> to be used include metal applied with surface treatment, such as plating, with high stability over time.

The distance from the movable reflection unit <NUM> to the structure <NUM> is shorter than the distance from the movable reflection unit <NUM> to the target object. Accordingly, the time elapsed between emission of the electromagnetic waves from the emission unit <NUM> and receiving of the electromagnetic waves by the receiving unit <NUM> with reflection of the electromagnetic waves by the structure <NUM> in between is shorter than the time elapsed between emission of the electromagnetic waves from the emission unit <NUM> and receiving of the electromagnetic waves by the receiving unit <NUM> with reflection of the electromagnetic waves by the target object in between. Accordingly, based on the time difference between signals generated in the receiving unit <NUM>, the sensor device <NUM> can determine whether a signal generated in the receiving unit <NUM> is a signal caused by the structure <NUM> or a signal caused by the target object.

The sensor device <NUM> may include the structure <NUM>. Alternatively, the structure <NUM> may be provided outside the sensor device <NUM>. When the sensor device <NUM> includes the structure <NUM>, for example, the structure <NUM> may be provided in a window part of a housing accommodating members constituting the sensor device <NUM>, such as the emission unit <NUM>, the movable reflection unit <NUM>, the receiving unit <NUM>, and the beam splitter <NUM>, that is, a part between the inside and the outside of the housing through which electromagnetic waves are transmitted. However, a location where the structure <NUM> is provided is not limited to the window part.

According to the present embodiment, the amendment unit <NUM>, the first adjustment unit <NUM>, and the second adjustment unit <NUM> represent function-based blocks rather than a hardware-based configuration. The amendment unit <NUM>, the first adjustment unit <NUM>, and the second adjustment unit <NUM> are provided by any combination of hardware and software centered on a CPU, a memory, a program loaded into the memory, a storage medium storing the program, such as a hard disk, and a network connection interface of any computer. Then, various modifications to the providing method and the device can be made.

The amendment unit <NUM> amends a detection result by the detection unit <NUM>, based on a receiving result of electromagnetic waves by the receiving unit <NUM>, the electromagnetic waves being reflected or scattered by the structure <NUM>. Amendment by the amendment unit <NUM> enables amendment of a deviation of a detection result of the deflection angle of the movable reflection unit <NUM> by the detection unit <NUM> from a detection result in a design state.

<FIG> is a diagram illustrating an example of a relation among the structure <NUM>, the scanning line L of the movable reflection unit <NUM>, and spots projected on the scanning line L.

In <FIG>, the scanning line L extends from the positive direction toward the negative direction of the second direction Y, that is, the linear drive direction of the movable reflection unit <NUM> while being folded back in the first direction X, that is, the resonance drive direction of the movable reflection unit <NUM>.

<FIG> illustrate eight spots positioned on the scanning line L, that is, a first spot S1, a second spot S2, a third spot S3, a fourth spot S4, a fifth spot S5, a sixth spot S6, a seventh spot S7, and an eighth spot S8. Each spot is generated by electromagnetic waves being emitted from the emission unit <NUM> and being reflected toward the structure <NUM> by the movable reflection unit <NUM>.

Each of the first spot S1, the second spot S2, the third spot S3, and the fourth spot S4 is a spot used for amendment by the amendment unit <NUM>. At least part of the first spot S1, the second spot S2, the third spot S3, and the fourth spot S4 is projected on the structure <NUM>. Note that the first spot S1, the second spot S2, the third spot S3, and the fourth spot S4 may be used for sensing by the sensor device <NUM>. The first spot S1 and the second spot S2 deviate in the linear drive direction of the movable reflection unit <NUM>, that is, the second direction Y. The second spot S2 is positioned outside the first spot S1 in the second direction Y in a region where the scanning line L is formed. The third spot S3 and the fourth spot S4 deviate in the resonance drive direction of the movable reflection unit <NUM>, that is, the first direction X. The fourth spot S4 is positioned outside the third spot S3 in the first direction X in the region where the scanning line L is formed.

Each of the fifth spot S5, the sixth spot S6, the seventh spot S7, and the eighth spot S8 is part of spots used for sensing by the sensor device <NUM>. No part of the fifth spot S5, the sixth spot S6, the seventh spot S7, and the eighth spot S8 is projected on the structure <NUM>. Accordingly, energy of electromagnetic waves projected on the target object is not reduced by the structure <NUM> for the fifth spot S5, the sixth spot S6, the seventh spot S7, and the eighth spot S8, and sensing of the target object can be efficiently performed. The fifth spot S5 and the sixth spot S6 deviate leftward relative to the first spot S1 and the second spot S2, respectively. The seventh spot S7 and the eighth spot S8 deviate upward relative to the third spot S3 and the fourth spot S4, respectively.

The structure <NUM> is positioned outside the region where the scanning line L of the movable reflection unit <NUM> is formed. Assuming that the movable reflection unit <NUM> is positioned inside the region where the scanning line L is formed, the sensor device <NUM> may not be able to detect a target object in a region where the structure <NUM> is placed, or detection performance of the device may be degraded. On the other hand, in the example illustrated in <FIG>, a region where the sensor device <NUM> cannot detect a target object or detection performance of the device is degraded can be limited to outside the region where the scanning line L of the movable reflection unit <NUM> is formed.

The amendment unit <NUM> may amend a detection result by the detection unit <NUM>, based on a relation between a first receiving value of electromagnetic waves by the receiving unit <NUM>, the electromagnetic waves being reflected or scattered by a predetermined first part of the structure <NUM>, and a second receiving value of electromagnetic waves by the receiving unit <NUM>, the electromagnetic waves being reflected or scattered by a predetermined second part of the structure <NUM>. In this case, the amendment unit <NUM> may amend the detection result by the detection unit <NUM>, based on a relation between a relation between the first receiving value and the second receiving value, such as at least either one of the difference and the ratio between the first receiving value and the second receiving value, and a deviation of the detection result by the detection unit <NUM> from a detection result in a reference state such as a design state or an initial state.

According to the claimed invention the amendment unit <NUM> amends the detection result by the detection unit <NUM>, based on a comparison result between a relation between the first receiving value and the second receiving value, and a relation between a first reference receiving value of electromagnetic waves by the receiving unit <NUM>, the electromagnetic waves being reflected or scattered by the first part of the structure <NUM> when the detection unit <NUM> operates in the reference state, and a second reference receiving value of electromagnetic waves by the receiving unit <NUM>, the electromagnetic waves being reflected or scattered by the second part of the structure <NUM> when the detection unit <NUM> operates in the reference state. The relation between the first reference receiving value and the second reference receiving value may be a known predetermined reference relation. For example, at least either one of the difference and the ratio between the first reference receiving value and the second reference receiving value may be a known predetermined reference value. In this case, when the sensitivity of the detection unit <NUM> varies from the sensitivity when the detection unit <NUM> is in the reference state due to a certain factor such as temperature and, as a result, the deflection angle of the movable reflection unit <NUM> varies from the deflection angle when the detection unit <NUM> is in the reference state, the relation between the first receiving value and the second receiving value varies from the predetermined reference relation. The amendment unit <NUM> may amend the detection result by the detection unit <NUM> such that the relation between the first receiving value and the second receiving value returns to the predetermined reference relation. For example, the first reference receiving value and the second reference receiving value may be substantially equal to each other.

In one example, the first part of the structure <NUM> may be a region on the structure <NUM> on which the first spot S1 is projected and the vicinity of the region, and the second part of the structure <NUM> may be a region on the structure <NUM> on which the second spot S2 is projected and the vicinity of the region. In other words, the first part and the second part of the structure <NUM> may deviate from each other in the linear drive direction of the movable reflection unit <NUM>, that is, the second direction Y.

The first adjustment unit <NUM> can adjust the position of the structure <NUM> so that the relation between the first reference receiving value and the second reference receiving value is a predetermined reference relation. For example, the first adjustment unit <NUM> can move the structure <NUM> along the second direction Y. Thus, a relation between the first reference receiving value for the first spot S1 and the second reference receiving value for the second spot S2 can be the predetermined reference relation.

In another example, the first part of the structure <NUM> may be a region on the structure <NUM> on which the third spot S3 is projected and the vicinity of the region, and the second part of the structure <NUM> may be a region on the structure <NUM> on which the fourth spot S4 is projected and the vicinity of the region. In other words, the first part and the second part of the structure <NUM> may deviate from each other in the resonance drive direction of the movable reflection unit <NUM>, that is, the first direction X.

The second adjustment unit <NUM> can adjust an emission timing of electromagnetic waves from the emission unit <NUM> so that the relation between the first reference receiving value and the second reference receiving value is a predetermined reference relation. Thus, a relation between the first reference receiving value for the third spot S3 and the second reference receiving value for the fourth spot S4 can be the predetermined reference relation.

Adjustment of the position of the structure <NUM> by the first adjustment unit <NUM> and adjustment of the emission timing of electromagnetic waves from the emission unit <NUM> by the second adjustment unit <NUM> may be combined as appropriate. For example, the first adjustment unit <NUM> may move the structure <NUM> in the second direction Y to amend a detection result of the deflection angle of the movable reflection unit <NUM> in the second direction Y by the detection unit <NUM>, and the second adjustment unit <NUM> may adjust the emission unit <NUM> to amend a detection result of the deflection angle of the movable reflection unit <NUM> in the first direction X by the detection unit <NUM>. In this case, the structure <NUM> may be unmovably fixed along the first direction X. Alternatively, the first adjustment unit <NUM> may move the structure <NUM> in both the first direction X and the second direction Y to amend a detection result of the deflection angle of the movable reflection unit <NUM> in the first direction X and second direction Y by the detection unit <NUM>. In this case, the second adjustment unit <NUM> may not adjust the emission unit <NUM>.

<FIG> is a graph illustrating an example of signals generated in the receiving unit <NUM> by the first spot S1 and the second spot S2 that are illustrated in <FIG>. <FIG> is a graph illustrating an example of changes in a receiving value S(S1) of a signal generated in the receiving unit <NUM> by the first spot S1 and a receiving value S(S2) of a signal generated in the receiving unit <NUM> by the second spot S2 when the deflection angle of the movable reflection unit <NUM> in the second direction Y varies. <FIG> is a graph illustrating the difference S(S1) - S(S2) between the receiving values S(S1) and S(S2) illustrated in <FIG>. <FIG> is a graph illustrating an example of changes in a receiving value S(S3) of a signal generated in the receiving unit <NUM> by the third spot S3 and a receiving value S(S4) of a signal generated in the receiving unit <NUM> by the fourth spot S4 when the deflection angle of the movable reflection unit <NUM> in the first direction X varies. <FIG> is a graph illustrating the difference S(S3) - S(S4) between the two receiving values S(S3) and S(S4) illustrated in <FIG>.

In <FIG>, a signal having a peak value a indicates the signal generated by the first spot S1. A signal having a peak value b indicates the signal generated by the second spot S2. A receiving value of a signal generated in the receiving unit <NUM> by each spot such as the receiving value S(S1), S(S2), S(S3), or S(S4) in <FIG> is a peak value of the signal generated in the receiving unit <NUM> by the spot, such as the peak value a or b in <FIG>.

The horizontal axis of the graph in <FIG> indicates the deflection angle of the movable reflection unit <NUM> in the second direction Y. The vertical axis of the graph in <FIG> indicates the intensity of each of the two receiving values S(S1) and S(S2). A solid line labeled "PY" indicates the deflection angle of the movable reflection unit <NUM> in the second direction Y in the reference state. For example, when the movable reflection unit <NUM> deflects significantly in the second direction Y in the example illustrated in <FIG>, the first spot S1 and the second spot S2 move outward, leading to decrease in the area of the first spot S1 projected on the structure <NUM> and resulting decrease in the receiving value S(S1), and increase in the area of the second spot S2 projected on the structure <NUM> and resulting increase in the receiving value S(S2). Accordingly, the receiving values S(S1) and S(S2) change in response to the change in the deflection angle of the movable reflection unit <NUM> in the second direction Y, as illustrated in the graph in <FIG>.

The horizontal axis of the graph in <FIG> indicates the deflection angle of the movable reflection unit <NUM> in the second direction Y. The vertical axis of the graph in <FIG> indicates the difference between the two receiving values S(S1) and S(S2). A solid line labeled "PY" indicates the deflection angle of the movable reflection unit <NUM> in the second direction Y in the reference state.

The horizontal axis of the graph in <FIG> indicates the deflection angle of the movable reflection unit <NUM> in the first direction X. The vertical axis of the graph in <FIG> indicates the intensity of each of the two receiving values S(S3) and S(S4). A solid line labeled "PX" indicates the deflection angle of the movable reflection unit <NUM> in the first direction X in the reference state. As the value on the horizontal axis increases, the deflection of the movable reflection unit <NUM> in the first direction X increases. For example, when the movable reflection unit <NUM> deflects significantly in the first direction X in the example illustrated in <FIG>, the third spot S3 and the fourth spot S4 move outward, leading to decrease in the area of the third spot S3 projected on the structure <NUM> and resulting decrease in the receiving value S(S3), and increase in the area of the fourth spot S4 projected on the structure <NUM> and resulting increase in the receiving value S(S4). Accordingly, the receiving values S(S3) and S(S4) change in response to the change in the deflection angle of the movable reflection unit <NUM> in the first direction X, as illustrated in the graph in <FIG>.

The horizontal axis of the graph in <FIG> indicates the deflection angle of the movable reflection unit <NUM> in the first direction X. The vertical axis of the graph in <FIG> indicates the difference between the two receiving values S(S3) and S(S4). A solid line labeled "PX" indicates the deflection angle of the movable reflection unit <NUM> in the first direction X in the reference state.

For example, the difference between the first reference receiving value for the first spot S1 and the second reference receiving value for the second spot S2 may be zero. For example, in <FIG> and <FIG>, the first reference receiving value is the receiving value S(S1) in the reference state, and the second reference receiving value is the receiving value S(S2) in the reference state. In <FIG>, S(S1) - S(S2) may be set to be zero in the reference state. When the deflection angle of the movable reflection unit <NUM> in the second direction Y is smaller than the deflection angle of the movable reflection unit <NUM> in the second direction Y in the reference state, S(S1) - S(S2) is a positive value. In this case, the amendment unit <NUM> may amend the detection result by the detection unit <NUM> such that S(S1) - S(S2) returns to zero, in other words, the deflection angle of the movable reflection unit <NUM> in the second direction Y increases. When the deflection angle of the movable reflection unit <NUM> in the second direction Y is greater than the deflection angle of the movable reflection unit <NUM> in the second direction Y in the reference state, S(S1) - S(S2) is a negative value. In this case, the amendment unit <NUM> may amend the detection result by the detection unit <NUM> such that S(S1) - S(S2) returns to zero, in other words, the deflection angle of the movable reflection unit <NUM> in the second direction Y decreases. Accordingly, amendment of the detection result by the amendment unit <NUM> amends a drive signal of the movable reflection unit <NUM>, and the deflection angle of the movable reflection unit <NUM> in the second direction Y is kept to the deflection angle in the reference state.

For example, the difference between the first reference receiving value for the third spot S3 and the second reference receiving value for the fourth spot S4 may be zero. For example, in <FIG> and <FIG>, the first reference receiving value is the receiving value S(S3) in the reference state, and the second reference receiving value is the receiving value S(S4) in the reference state. In <FIG>, S(S3) - S(S4) may be set to be zero in the reference state. When the deflection angle of the movable reflection unit <NUM> in the first direction X is smaller than the deflection angle of the movable reflection unit <NUM> in the first direction X in the reference state, S(S3) - S(S4) is a positive value. In this case, the amendment unit <NUM> may amend the detection result by the detection unit <NUM> such that S(S3) - S(S4) returns to zero, in other words, the deflection angle of the movable reflection unit <NUM> in the first direction X increases. When the deflection angle of the movable reflection unit <NUM> in the first direction X is greater than the deflection angle of the movable reflection unit <NUM> in the first direction X in the reference state, S(S3) - S(S4) is a negative value. In this case, the amendment unit <NUM> may amend the detection result by the detection unit <NUM> such that S(S3) - S(S4) returns to zero, in other words, the deflection angle of the movable reflection unit <NUM> in the first direction X decreases. Accordingly, amendment of the detection result by the amendment unit <NUM> amends the drive signal of the movable reflection unit <NUM>, and the deflection angle of the movable reflection unit <NUM> in the second direction Y is kept to the deflection angle in the reference state.

<FIG> is a diagram illustrating an example of a relation among a structure <NUM>, a scanning line L of a movable reflection unit <NUM>, and spots projected on the scanning line L in a sensor device <NUM> according to a modified example. <FIG> is a diagram of a region where the scanning line L is formed, the region being viewed from the movable reflection unit <NUM> side.

In <FIG>, a ninth spot S9 and a tenth spot S10 that are arranged roughly at the center of the region in a second direction Y where the scanning line L is formed and along a resonance drive direction of the movable reflection unit <NUM>, that is, a first direction X are indicated by open circles. An eleventh spot S11 and a twelfth spot S12 that are arranged in an upper part of the region in the second direction Y where the scanning line L is formed and along the resonance drive direction of the movable reflection unit <NUM>, that is, the first direction X are indicated by open circles.

The structure <NUM> intersects the scanning line L of the movable reflection unit <NUM>. Specifically, the structure <NUM> is a member such as a wire linearly extending along the second direction Y. The width of the structure <NUM> in the first direction X is narrower than the width of a spot in the first direction X, the spot being generated by the movable reflection unit <NUM>. Accordingly, electromagnetic waves attenuated by the structure <NUM> can be kept low.

In the example illustrated in <FIG>, for example, a first part of the structure <NUM> may be a part of the structure <NUM> on which the ninth spot S9 is projected. A second part of the structure <NUM> may be a part of the structure <NUM> on which the tenth spot S10 is projected. The intensity of a signal generated in a receiving unit <NUM> by electromagnetic waves reflected by the structure <NUM>, such as a first reference receiving value or a second reference receiving value, varies with a projection area of a spot on the structure <NUM> and an intensity distribution of the spot.

<FIG> is a graph illustrating an example of changes in a receiving value S(S9) generated in the receiving unit <NUM> by the ninth spot S9 and a receiving value S(S10) generated in the receiving unit <NUM> by the tenth spot S10 when a deflection angle of the movable reflection unit <NUM> in the first direction X varies. <FIG> is a graph illustrating the difference between the two receiving values S(S9) and S(S10) illustrated in <FIG>.

The horizontal axis of the graph in <FIG> indicates the deflection angle of the movable reflection unit <NUM> in the first direction X. The vertical axis of the graph in <FIG> indicates the intensity of each of the two receiving values S(S9) and S(S10). A solid line labeled "PX" indicates the deflection angle of the movable reflection unit <NUM> in the first direction X in a reference state. As the value on the horizontal axis increases, the deflection of the movable reflection unit <NUM> in the first direction X increases.

The horizontal axis of the graph in <FIG> indicates the deflection angle of the movable reflection unit <NUM> in the second direction Y. The vertical axis of the graph in <FIG> indicates the difference S(S10) - S(S9) between the two receiving values S(S9) and S(S10). A solid line labeled "PY" indicates the deflection angle of the movable reflection unit <NUM> in the second direction Y in the reference state.

<FIG> is a diagram illustrating an example of a relation among the structure <NUM>, the ninth spot S9, and the tenth spot S10 in the reference state. <FIG> is a diagram illustrating an example of a relation among the structure <NUM>, the ninth spot S9, and the tenth spot S10 when the deflection angle of the movable reflection unit <NUM> in the first direction X is smaller than the deflection angle in the reference state. <FIG> is a diagram illustrating an example of a relation among the structure <NUM>, the ninth spot S9, and the tenth spot S10 when the deflection angle of the movable reflection unit <NUM> in the first direction X is greater than the deflection angle in the reference state. A double-pointed arrow passing through the ninth spot S9 and the tenth spot S10 in <FIG> indicates a direction of oscillation of the movable reflection unit <NUM> in the first direction X.

In <FIG>, the area of the ninth spot S9 projected on the structure <NUM> is substantially equal to the area of the tenth spot S10 projected on the structure <NUM>. Accordingly, S(S10) - S(S9) in the reference is zero, as illustrated in <FIG>.

In <FIG>, the area of the tenth spot S10 projected on the structure <NUM> is greater than the area of the ninth spot S9 projected on the structure <NUM>. Accordingly, S(S10) - S(S9) illustrated in <FIG> is a positive value, and the deflection angle of the movable reflection unit <NUM> in the first direction X being smaller than the deflection angle in the reference state can be detected.

In <FIG>, the area of the tenth spot S10 projected on the structure <NUM> is smaller than the area of the ninth spot S9 projected on the structure <NUM>. Accordingly, S(S10) - S(S9) illustrated in <FIG> is a negative value, and the deflection angle of the movable reflection unit <NUM> in the first direction X being greater than the deflection angle in the reference state can be detected.

For example, the difference between the first reference receiving value for the ninth spot S9 and the second reference receiving value for the tenth spot S10 may be zero. For example, in <FIG> and in <FIG>, the first reference receiving value is the receiving value S(S9) in the reference state, and the second reference receiving value is the receiving value S(S10) in the reference state. In <FIG>, S(S10) - S(S9) may be set to be zero in the reference state. When the deflection angle of the movable reflection unit <NUM> in the second direction Y varies from the deflection angle of the movable reflection unit <NUM> in the second direction Y in the reference state, and S(S10) - S(S9) is a positive or negative value, the amendment unit <NUM> may amend a detection result by a detection unit <NUM> such that S(S10) - S(S9) returns to zero.

An example of using the ninth spot S9 and the tenth spot S10 has been described in <FIG>. However, use of the eleventh spot S11 and the twelfth spot S12 may be the same as the example described by using <FIG>.

<FIG> is a graph illustrating an example of a relation between the deflection angle of the movable reflection unit <NUM> in the second direction Y and the difference S(S11) - S(S12) between a receiving value S(S11) of a signal generated in the receiving unit <NUM> by the eleventh spot S11 and a receiving value S(S12) of a signal generated in the receiving unit <NUM> by the twelfth spot S12.

In <FIG>, the horizontal axis of the graph indicates the deflection angle of the movable reflection unit <NUM> in the second direction Y. The vertical axis of the graph indicates the difference S(S11) - S(S12) between the receiving value S(S11) of the signal generated in the receiving unit <NUM> by the eleventh spot S11 and the receiving value S(S12) of the signal generated in the receiving unit <NUM> by the twelfth spot S12.

<FIG> is a diagram illustrating an example of a relation among the structure <NUM> in the reference state, the ninth spot S9, the tenth spot S10, the eleventh spot S11, and the twelfth spot S12. <FIG> is a diagram illustrating an example of a relation among the structure <NUM>, the ninth spot S9, the tenth spot S10, the eleventh spot S11, and the twelfth spot S12 when the deflection angle of the movable reflection unit <NUM> in the second direction Y is smaller than the deflection angle in the reference state. <FIG> is a diagram illustrating an example of a relation among the structure <NUM>, the ninth spot S9, the tenth spot S10, the eleventh spot S11, and the twelfth spot S12 when the deflection angle of the movable reflection unit <NUM> in the first direction X is greater than the deflection angle in the reference state. In <FIG>, each of a double-pointed arrow passing through the ninth spot S9 and the tenth spot S10, and a double-pointed arrow passing through the eleventh spot S11 and the twelfth spot S12 indicates a direction of oscillation of the movable reflection unit <NUM> in the first direction X.

In <FIG>, the area of the ninth spot S9 projected on the structure <NUM> is substantially equal to the area of the tenth spot S10 projected on the structure <NUM>.

The difference between the area of the eleventh spot S11 projected on the structure <NUM> and the area of the twelfth spot S12 projected on the structure <NUM> in <FIG> is smaller than the difference between the area of the eleventh spot S11 projected on the structure <NUM> and the area of the twelfth spot S12 projected on the structure <NUM> in <FIG>. Accordingly, as illustrated in <FIG>, the difference S(S11) - S(S12) when the deflection angle of the movable reflection unit <NUM> in the second direction Y is smaller than the deflection angle in the reference state is smaller than the difference S(S11) - S(S12) in the reference state. In this case, the amendment unit <NUM> may amend the detection result by the detection unit <NUM> such that that the difference S(S11) - S(S12) returns to the difference S(S11) - S(S12) in the reference state.

The difference between the area of the eleventh spot S11 projected on the structure <NUM> and the area of the twelfth spot S12 projected on the structure <NUM> in <FIG> is greater than the difference between the area of the eleventh spot S11 projected on the structure <NUM> and the area of the twelfth spot S12 projected on the structure <NUM> in <FIG>. Accordingly, as illustrated in <FIG>, the difference S(S11) - S(S12) when the deflection angle of the movable reflection unit <NUM> in the second direction Y is greater than the deflection angle in the reference state is greater than the difference S(S11) - S(S12) in the reference state. In this case, the amendment unit <NUM> may amend the detection result by the detection unit <NUM> such that the difference S(S11) - S(S12) returns to the difference S(S11) - S(S12) in the reference state.

While the embodiment and the modified example have been described above with reference to the drawings, the embodiment and the modified example are exemplifications of the present invention, and various configurations other than those described above may be employed.

For example, the sensor device <NUM> according to the embodiment is a coaxial LiDAR. However, the sensor device <NUM> may be a biaxial LiDAR.

Claim 1:
A sensor device (<NUM>) comprising:
a movable reflection unit (<NUM>) reflecting an electromagnetic wave toward inside a predetermined scanning range;
a detection unit (<NUM>) detecting a deflection angle of the movable reflection unit (<NUM>); and
a receiving unit (<NUM>) receiving the electromagnetic wave reflected or scattered by a structure (<NUM>) positioned in the scanning range; characterized in that
the sensor device (<NUM>) further comprises an amendment unit (<NUM>) amending a detection result by the detection unit (<NUM>), based on a receiving result of the electromagnetic wave by the receiving unit (<NUM>), the electromagnetic wave being reflected by the structure (<NUM>), wherein
the amendment unit (<NUM>) amends the detection result by the detection unit (<NUM>), based on a relation between a first receiving value of the electromagnetic wave by the receiving unit (<NUM>), the electromagnetic wave being reflected or scattered by a first part of the structure (<NUM>), and a second receiving value of the electromagnetic wave by the receiving unit (<NUM>), the electromagnetic wave being reflected or scattered by a second part of the structure (<NUM>), wherein
the amendment unit (<NUM>) amends the detection result by the detection unit (<NUM>), based on a comparison result between the relation between the first receiving value and the second receiving value, and a relation between a first reference receiving value of the electromagnetic wave by the receiving unit (<NUM>), the electromagnetic wave being reflected or scattered by the first part of the structure (<NUM>), when the detection unit (<NUM>) operates in a reference state and a second reference receiving value of the electromagnetic wave by the receiving unit (<NUM>), the electromagnetic wave being reflected or scattered by the second part of the structure (<NUM>), when the detection unit (<NUM>) operates in the reference state.