JP2012163642A - Optical deflection element, laser device, and sensing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical deflection element which can be easily miniaturized and with which a large deflection angle can be obtained.SOLUTION: A plurality of optical deflection units each containing a periodical polarization inversion structure that deflects incident light in an XY plane according to an applied voltage and a grating for deflecting the light transmitted through the periodical polarization inversion structure in a plane containing the travelling direction of the light and perpendicular to the XY plane are stacked in a direction perpendicular to the XY plane (Z axis direction). A groove period of each grating in the plurality of optical deflection units is different from each other. In this case, the miniaturized optical deflection element can emit light with a large deflection angle in two directions.

Description

  The present invention relates to an optical deflection element, a laser device, and a sensing device. More specifically, the present invention relates to an optical deflection element capable of individually deflecting incident light in two planes intersecting each other, and a laser apparatus having the optical deflection element. The present invention relates to a sensing device including the laser device.

  Conventionally, as an optical deflector for deflecting light, one using a galvanometer mirror, a polygon mirror, an acoustooptic device, an electrooptic device, or the like is known.

  An optical deflector using a galvanometer mirror has the disadvantage that it is difficult to scan light at high speed.

  An optical deflector using a polygon mirror is advantageous in that it can scan light at a high speed and has a large deflection angle. However, since it has a mechanical part, vibration and enlargement of the optical system are inevitable. .

  On the other hand, an optical deflector using an acousto-optic element and an electro-optic element does not have a mechanical part, and thus does not have a problem of vibration or an increase in size.

  For example, Patent Document 1 discloses a two-dimensional optical deflector that two-dimensionally controls the traveling direction of light using an acousto-optic effect and a thermo-optic effect in a thin-film optical waveguide formed on a substrate. .

  Patent Document 2 discloses a two-dimensional optical deflector that two-dimensionally controls the traveling direction of light using an acousto-optic effect, an electro-optic effect, and a thermo-optic effect in a thin-film optical waveguide formed on a substrate. Is disclosed.

  Patent Document 3 discloses an optical deflection element that includes an optical waveguide having an electro-optic effect and an output prism, and deflects a light beam in a first direction and a second direction that intersects the first direction. Is disclosed.

  However, the two-dimensional optical deflectors disclosed in Patent Document 1 and Patent Document 2 have the disadvantage that the amount of change in the deflection angle in a direction different from the plane of the optical waveguide, that is, the exit angle, is extremely small.

  In addition, the optical deflection element disclosed in Patent Document 3 requires an expensive prism, which has the disadvantage of increasing the cost. Further, since it is necessary to align the prism with high accuracy, there is a disadvantage that adjustment work takes time. Further, since it is not suitable for integration of elements, there is a disadvantage that it is difficult to reduce the size.

  The present invention has been made under such circumstances, and a first object of the invention is to provide an optical deflection element that can be easily miniaturized and can obtain a large deflection angle in two directions.

  A second object of the present invention is to provide a laser apparatus that is small and can greatly change the emission angle of laser light in a two-dimensional manner without causing an increase in cost.

  A third object of the present invention is to provide a sensing device that is capable of sensing a small and wide range without incurring an increase in cost.

  From a first viewpoint, the present invention provides a light incident portion, a first deflection portion that deflects light via the light incident portion in a first plane according to an applied voltage, and the first deflection. A light deflecting unit including a second deflecting unit including a grating that deflects light that has passed through the second part within a second surface that includes a traveling direction of the light and is orthogonal to the first surface. A plurality of light deflection elements which are stacked in a direction orthogonal to each other and have different groove periods of the gratings in the plurality of light deflection units.

  According to this, downsizing is easy and a large deflection angle can be obtained in two directions.

  According to a second aspect of the present invention, the light deflection element of the present invention, a plurality of laser light sources that emit light respectively incident on the plurality of light deflection units of the light deflection element, and the plurality of light deflection units And a voltage control device that controls a voltage applied to each first deflection unit.

  According to this, since the optical deflecting element of the present invention is provided, as a result, the emission angle of the laser beam can be greatly changed two-dimensionally without increasing the cost.

  According to a third aspect of the present invention, the laser device of the present invention, a light receiver that receives light emitted from the laser device and reflected by an object, the emission direction of the light from the laser device, and the light reception A signal processing device for obtaining position information of the object based on an output signal of the device.

  According to this, since the laser device of the present invention is provided, as a result, it is possible to sense a small and wide range without increasing the cost.

1 is an external view of a vehicle equipped with a laser radar according to an embodiment of the present invention. It is a block diagram for demonstrating the structure of the front monitoring apparatus which concerns on one Embodiment of this invention. It is a block diagram for demonstrating the structure of a laser radar. It is a figure for demonstrating the structure of the light source device in FIG. FIG. 4 is a diagram (No. 1) for describing a configuration of an optical deflection element in FIG. 3; FIG. 4 is a (second) diagram for explaining the configuration of the optical deflection element in FIG. 3; It is a figure for demonstrating the structure of an optical deflection | deviation unit. It is a figure for demonstrating the periodic polarization inversion structure body and grating in a core layer. FIG. 9A to FIG. 9D are views (No. 1) for describing a method of creating an optical deflection unit, respectively. FIG. 10A to FIG. 10C are views (No. 2) for describing a method of creating an optical deflection unit, respectively. FIG. 11A to FIG. 11C are views (No. 3) for describing a method of creating an optical deflection unit, respectively. FIGS. 12A to 12C are views (No. 4) for describing the method of creating the optical deflection unit, respectively. FIGS. 13A to 13C are views (No. 5) for describing a method of creating the optical deflection unit, respectively. It is a figure for demonstrating stacking of three light deflection | deviation units. It is a figure for demonstrating the light beam which injects into three light deflection | deviation units. It is a figure for demonstrating the application of the voltage from a voltage control apparatus. 17A and 17B are diagrams for explaining the deflection of the light beam in the XY plane, and FIG. 17C explains the deflection angle of the light beam in the XY plane. It is a figure for doing. It is a figure for demonstrating the deflection | deviation by each grating. It is a figure for demonstrating drive control of each semiconductor laser by a sensing control apparatus. It is a figure for demonstrating the deflection surface of each light beam inject | emitted from an optical deflection | deviation element. It is a figure for demonstrating the optical path of each light beam in XY plane when the voltage is not applied. It is a figure for demonstrating the optical path of each light beam inject | emitted from three light deflection units, when three light deflection units are arrange | positioned at the Y-axis direction. It is a block diagram for demonstrating the structure of an audio | voice / alarm generator. It is a figure for demonstrating the modification of a light source device. It is a figure for demonstrating the modification 1 of a light receiver. It is a figure for demonstrating the modification 2 of a light receiver. It is a figure for demonstrating the modification 3 of a light receiver. It is a figure for demonstrating the example in which the grating is formed also in the incident side of the core layer. It is a figure for demonstrating an example of the light source device corresponding to FIG.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows an appearance of a vehicle 1 equipped with a vehicle-mounted laser radar 20 as a sensing device according to an embodiment.

  As an example, the laser radar 20 is attached in the vicinity of a license plate in front of the vehicle 1. In the present specification, in the XYZ three-dimensional orthogonal coordinate system, the gravity direction is described as the Z-axis direction, and the forward direction of the vehicle 1 is described as the + X direction.

  As shown in FIG. 2 as an example, the vehicle 1 includes a display device 30, a main control device 40, a memory 50, a sound / alarm generating device 60, and the like. These are electrically connected via a bus 70.

  Here, the forward monitoring device 10 is configured by the laser radar 20, the display device 30, the main control device 40, the memory 50, and the sound / alarm generating device 60.

  As shown in FIG. 3 as an example, the laser radar 20 includes a light source device 220, a voltage control device 230, a light deflection element 240, a sensing control device 300, a light receiver 350, and the like.

  Here, as shown in FIG. 4 as an example, the light source device 220 includes three semiconductor lasers (221a, 221b, 221c), three coupling lenses (223a, 223b, 223c), a condensing lens 225, and a cylindrical lens. A lens 227 is provided.

  Each semiconductor laser emits laser light having a wavelength of 650 nm in the + X direction.

  The coupling lens 223a is disposed on the optical path of the light beam emitted from the semiconductor laser 221a, and makes the light beam substantially parallel light.

  The coupling lens 223b is disposed on the optical path of the light beam emitted from the semiconductor laser 221b, and makes the light beam substantially parallel light.

  The coupling lens 223c is disposed on the optical path of the light beam emitted from the semiconductor laser 221c, and makes the light beam substantially parallel light.

  Hereinafter, for convenience, the light beam emitted from the semiconductor laser 221a is referred to as “light beam LBa”, the light beam emitted from the semiconductor laser 221b is referred to as “light beam LBb”, and the light beam emitted from the semiconductor laser 221c is referred to as “light beam LBc”.

  The condenser lens 225 is disposed on the optical path of the light beam LBa via the coupling lens 223a, the light beam LBb via the coupling lens 223b, and the light beam LBc via the coupling lens 223c.

  The cylindrical lens 227 is disposed on the + X side of the condenser lens 225, and focuses the light beam LBa, the light beam LBb, and the light beam LBc via the condenser lens 225 in the Z-axis direction.

  Returning to FIG. 3, the light deflection element 240 is arranged on the + X side of the light source device 220.

  As shown in FIG. 5 and FIG. 6 as an example, the light deflection element 240 has three light deflection units (240a, 240b, 240c). Each light deflection unit has a different dimension (length) in the X-axis direction. Here, the length La of the light deflection unit 240a> the length Lb of the light deflection unit 240b> the length Lc of the light deflection unit 240c is set.

  The three light deflection units (240a, 240b, 240c) are stacked in the + Z direction in the order of the light deflection unit 240a, the light deflection unit 240b, and the light deflection unit 240c. The positions of the end portions on the −X side of the respective light deflection units are substantially the same with respect to the X-axis direction.

  The three light deflection units (240a, 240b, 240c) have the same configuration. Therefore, when it is not necessary to distinguish the three light deflection units (240a, 240b, 240c), they are collectively referred to as the light deflection unit 240x.

  As shown in FIG. 7 as an example, the optical deflection unit 240x includes a substrate 241, an adhesive 242, a lower electrode 243, a lower cladding layer 244, a core layer 245, an upper cladding layer 246, an upper electrode 247, and the like. Yes.

The core layer 245 is a plate-like member having a thickness of about 10 μm of lithium niobate (LiNbO ₃ ) crystal to which MgO is added.

  As an example, as shown in FIG. 8, the core layer 245 includes a grating 260 in which a plurality of grooves are formed in an arc shape in the vicinity of the end on the + X side. In the grating 260, the width of the concave portion and the width of the convex portion are the same. The depth of the recess is 50 nm. In the three light deflection units (240a, 240b, 240c), the groove periods of the grating 260 are different from each other. Here, the groove period Λa of the grating 260 in the light deflection unit 240a> the groove period Λb of the grating 260 in the light deflection unit 240b> the groove period Λc of the grating 260 in the light deflection unit 240c is set.

  Further, the core layer 245 has a periodically poled structure 250 from the −X side end portion to the vicinity of the grating 260 in the X-axis direction.

  In the periodically poled structure 250, two regions (250a, 250b) in which the directions of spontaneous polarization are opposite to each other are formed in prism shapes having opposite shapes in the XY cross section.

Returning to FIG. 7, the upper cladding layer 246 is a TaO ₅ layer having a thickness of 1 μm, and is formed on the + Z side of the periodically poled structure 250 in the core layer 245.

The lower cladding layer 244 is a TaO ₅ layer having a thickness of 1 μm, and is formed on the −Z side of the core layer 245.

  The upper electrode 247 is a Ti (titanium) layer having a thickness of 200 nm, and is formed on the + Z side of the upper cladding layer 246.

  The lower electrode 243 is a Ti (titanium) layer having a thickness of 200 nm, and is formed on the −Z side of the lower cladding layer 244.

The substrate 241 is a lithium niobate (LiNbO ₃ ) substrate. The substrate 241 is bonded to the lower electrode 243 with an adhesive 242.

  Here, since the same material is used for the core layer 245 and the substrate 241, the influence (separation) of thermal expansion can be reduced.

  Next, a method for creating the light deflection unit 240x will be briefly described.

(1) A core layer 245 having a periodically poled structure 250 is prepared (see FIGS. 9A to 9C). Note that FIG. 9C is a cross-sectional view taken along line AA in FIG.

(2) A lower cladding layer 244 is formed on the surface of the core layer 245 on the + Z side (see FIG. 9D).

(3) A lower electrode 243 is formed on the surface of the lower cladding layer 244 (see FIG. 10A). In the following description, the film in which the lower electrode 243 is formed is referred to as a “primary stacked body” for convenience.

(4) A substrate 241 is prepared, and an adhesive 242 is applied to the surface of the substrate 241 (see FIG. 10B).

(5) The primary laminate is turned upside down on the adhesive 242 and placed with the lower electrode 243 facing down (see FIG. 10C). In addition, what the board | substrate 241 and the primary laminated body were joined by the adhesive agent 242 is called "secondary laminated body" for convenience below.

(6) When the adhesive 242 is cured, the secondary laminated body is turned upside down, and the other surface of the core layer 245 is turned down (see FIG. 11A).

(7) The other surface of the core layer 245 in the secondary laminated body is polished so that the thickness of the core layer 245 is about 10 μm (see FIG. 11B).

(8) The secondary laminated body is turned upside down and the photoresist PR is applied to the other surface of the core layer 245 (see FIG. 11C).

(9) A grating pattern is drawn on the photoresist PR using an electron beam drawing apparatus. At this time, in the case of the optical deflection unit 240a, a pattern is drawn so that the groove period is Λa, in the case of the optical deflection unit 240b, a pattern is drawn so that the groove period is Λb, and in the case of the light deflection unit 240c, A pattern is drawn so that the groove period is Λc. Specifically, Λa = 500 nm, Λb = 420 nm, and Λc = 350 nm. Note that a grating pattern may be transferred to the surface of the photoresist PR using an exposure apparatus.

(10) A predetermined process is performed on the photoresist PR to form an etching mask (see FIG. 12A). Here, the resist pattern is used as an etching mask. However, the present invention is not limited to this. For example, metal may be deposited on the resist pattern, the metal pattern may be formed by lift-off, and the metal pattern may be used as the etching mask. .

(11) The other surface of the core layer 245 is dry-etched through the etching mask (see FIG. 12B).

(12) The etching mask is removed (see FIG. 12C). Thereby, the grating 260 is formed.

(13) An upper clad layer 246 is formed on a portion of the other surface of the core layer 245 excluding the grating 260 (see FIG. 13A).

(14) The upper electrode 247 is formed on the surface of the upper cladding layer 246 (see FIGS. 13B and 13C). Thereby, the light deflection unit 240x is obtained.

  Then, the three light deflection units (240a, 240b, 240c) individually created in this way are bonded with an adhesive as shown in FIG.

  In the light deflection element 240, the light beam LBa emitted from the light source device 220 is incident on the core layer 245 of the light deflection unit 240a, the light beam LBb is incident on the core layer 245 of the light deflection unit 240b, and the light beam LBc is incident on the light deflection unit 240c. It is positioned so as to be incident on the core layer 245 (see FIG. 15). That is, each core layer 245 is an optical waveguide.

  The voltage control device 230 individually applies a voltage to the upper electrode 247 of each light deflection unit based on an instruction from the sensing control device 300 (see FIG. 16). The lower electrode 243 of each light deflection unit is grounded.

  When a voltage is applied to the upper electrode 247 of each light deflection unit, a refractive index difference is generated between the region 250a and the region 250b in the periodically poled structure 250. This refractive index difference Δn is expressed by the following equation (1). Here, r is the Pockels constant, n is the refractive index of the material of the core layer 245, d is the thickness of the core layer 245, and V is the applied voltage.

Δn = −1 / 2 · r · n ³ · V / d (1)

  Therefore, when a voltage is applied from the voltage control device 230 to the upper electrode 247 while the light beam from the light source device 220 is incident on the core layer 245, the light beam is deflected in the XY plane according to the applied voltage. .

  For example, when V = + 150 [V], the light beam is deflected to the + Y side as shown in FIG. 17A as an example.

  Further, when V = −150 [V], the light beam is deflected to the −Y side as shown in FIG. 17B as an example.

  Thus, for example, when a voltage of −150 [V] to +150 [V] is applied to the upper electrode 247, the light beam can be deflected at a deflection angle (deflection angle) θx = 10 ° in the XY plane ( FIG. 17C). Note that the difference in the deflection direction in the XY plane due to the difference in wavelength is hardly the difference in wavelength used in this embodiment.

  The light beam that has passed through the periodically poled structure 250 is deflected by the grating 260 in a plane that includes the traveling direction of the light beam and that is orthogonal to the XY plane. The angle θz with respect to the Z-axis direction at this time is expressed by the following equation (2). Here, n (a) is the refractive index around the grating 260 (here, air), N is the effective refractive index of the core layer 245, q is the order of diffraction, λ is the wavelength of the light beam, and Λ is the groove of the grating 260. It is a period.

  n (a) · sin θz = N + q · λ / Λ (2)

  For example, when λ = 650 nm, N = 2.2, and q = −1, θz = 64 ° when Λ = 500 nm, θz = 41 ° when Λ = 420 nm, and θz = 20 ° when Λ = 350 nm. .

  That is, when viewed from the Y-axis direction, the light beam LBa incident on the light deflection unit 240a is emitted in a direction inclined by 64 ° (θa in FIG. 18) on the + X side with respect to the YZ plane. Further, the light beam LBb incident on the light deflection unit 240b is emitted in a direction inclined by 41 ° (θb in FIG. 18) on the + X side with respect to the YZ plane. Further, the light beam LBc incident on the light deflection unit 240c is emitted in a direction inclined by 20 ° (θc in FIG. 18) on the + X side with respect to the YZ plane. Therefore, the deflection angle (deflection angle) in the XZ plane is 44 ° (= 64 ° −20 °).

  The sensing control device 300 controls each drive signal so that the three semiconductor lasers (221a, 221b, 221c) of the light source device 220 are sequentially turned on (see FIG. 19). At the same time, the sensing control device 300 notifies the voltage control device 230 of information (timing information) regarding the lighting timing and extinguishing timing of each semiconductor laser.

  The voltage control device 230 controls the applied voltage V based on the timing information. Here, for each semiconductor laser, the applied voltage V is changed from −150 [V] → + 150 [V] or +150 [V] → −150 [V] within the time when the semiconductor laser is turned on. As a result, the light beam emitted from the optical deflection element 240 can be deflected two-dimensionally at a deflection angle (fluff angle) of 10 ° in the XY plane and at a deflection angle (fluff angle) of 44 ° in the XZ plane. Yes (see FIG. 20).

  Thus, the light deflection element 240 can emit a light beam in a wide area in front of the vehicle 1.

  By the way, when no voltage is applied from the voltage control device 230 to the upper electrode 247, as shown in FIG. 21, the optical paths of the light beams emitted from the respective light deflection units substantially coincide with each other when viewed from the Z-axis direction. As described above, adjustment is made when three light deflection units are stacked. In this case, since the centers of deflection in the core layer 245 coincide between the respective light deflection units, if the same voltage is applied to each upper electrode 247, the light flux emitted from each light deflection unit is The positions in the Y axis direction can be matched.

  As shown in FIG. 22, when three light deflection units are arranged along the Y-axis direction, the emission positions in the Y-axis direction are different among the light deflection units. Alignment of the luminous flux in the Y-axis direction becomes difficult, and adjustment is necessary depending on the projection distance.

  In the present embodiment, since the three light deflection units are superposed, the area occupied by the light deflection element can be reduced, which is suitable for downsizing of the laser radar 20. This becomes more effective as the number of light deflection units in the light deflection element increases.

  The light receiver 350 receives a light beam emitted from the light deflection element 240 and reflected by an object (for example, another vehicle) in front of the vehicle 1. The light receiver 350 generates a signal (photoelectric conversion signal) corresponding to the amount of received light, and outputs the signal to the sensing control device 300.

  The sensing control device 300 obtains the emission direction of the light flux from the semiconductor laser that is lit at that time and the applied voltage V at that time, and based on the emission direction and the signal from the light receiver 350, the size of the object, The position of the object with respect to the vehicle 1 is obtained. The data obtained here is stored in the memory 50 as monitoring data together with time information.

  Based on the monitoring data stored in memory 50, main controller 40 determines whether there is an object ahead of vehicle 1, whether the object is moving when there is an object, and whether the object is moving. When it is, the moving direction and moving speed are obtained. Then, the information is displayed on the display device 30.

  Further, when determining that there is a danger, main controller 40 outputs alarm information to voice / alarm generator 60.

  As shown in FIG. 23 as an example, the voice / alarm generator 60 includes a voice synthesizer 61, an alarm signal generator 62, a speaker 63, and the like.

  The voice synthesizer 61 has a plurality of voice data, and when alarm information is received from the main controller 40, the corresponding voice data is selected and output to the speaker 63.

  When the alarm signal generator 62 receives alarm information from the main controller 40, the alarm signal generator 62 generates a corresponding alarm signal and outputs it to the speaker 63.

  As apparent from the above description, the sensing device of the present invention is configured by the forward monitoring device 10 according to the present embodiment. The sensing control device 300 constitutes a signal processing device in the sensing device of the present invention. The main control device 40 and the sound / alarm generating device 60 constitute a monitoring control device in the sensing device of the present invention.

  Further, the light source device 220, the voltage control device 230, the light deflection element 240, and the sensing control device 300 constitute a radar device of the present invention. The sensing control device 300 constitutes a light source control device in the radar device of the present invention.

  As described above, according to the light deflection element 240 according to the present embodiment, the periodically poled structure 250 (first polarization) that deflects the incident light in the XY plane (in the first plane) according to the applied voltage. 1) and a grating 260 (second deflection unit) that deflects light that has passed through the periodically poled structure 250 within a plane (second plane) that includes the traveling direction of the light and is orthogonal to the XY plane. ) Are stacked in a direction perpendicular to the XY plane (Z-axis direction). The groove periods of the grating 260 in the plurality of light deflection units are different from each other.

In this case, it is small and can emit light with a large deflection angle in two directions. Further, the periodically poled structure 250 and the grating 260 can be easily provided on the core layer 245 which is a plate member of lithium niobate (LiNbO ₃ ) crystal to which MgO is added. That is, integration is easy and a large deflection angle can be obtained in a plane intersecting the optical waveguide surface.

  In addition, since the grating 260 is formed in the core layer 245 having the periodically poled structure 250, alignment between the periodically poled structure 250 and the grating 260 is not necessary.

  Unlike Patent Document 2 (Japanese Patent Laid-Open No. 58-130327), it is not necessary to supply electric power from the outside in order to deflect light in the XZ plane. That is, light can be deflected two-dimensionally with low power consumption.

  Further, since the emission angle from the light deflection element 240 can be changed by switching the light source to be turned on, the emission angle from the light deflection element 240 can be controlled at a very high speed.

  In addition, by designating the applied voltage from the voltage control device 230 and the light source to be lit, the emission direction of the light emitted from the light deflection element 240 can be directed to an arbitrary direction at a very high speed.

  Further, by controlling the applied voltage from the voltage control device 230 and the light source to be lit, light can be emitted within a specified range.

  Further, according to the front monitoring apparatus 10 according to the present embodiment, the light source device 220 having three semiconductor lasers (221a, 221b, 221c), the light deflection element 240 on which the light from the light source device 220 is incident, And a voltage control device 230 that individually controls the voltage applied to each upper electrode 247 of the light deflection element 240. Therefore, the laser beam emission angle can be greatly changed two-dimensionally in a small size.

  Further, according to the front monitoring apparatus 10 according to the present embodiment, the light receiver 350 that receives the light emitted from the light deflection element 240 and reflected by the object, the light emission direction from the light deflection element 240 and the light receiver 350. And a sensing control device 300 for obtaining the position information of the object based on the output signal. In this case, it is possible to sense a small and wide range without increasing the cost.

  In addition, since light can be emitted from the light deflection element 240 in a designated direction and a designated range, it is possible to focus on a range where danger is expected.

  In the above embodiment, as shown in FIG. 24 as an example, a semiconductor laser 221 having three light emitting units may be used in place of the three semiconductor lasers (221a, 221b, 221c). In place of the three coupling lenses (223a, 223b, 223c), a coupling lens 223 in which they are integrated may be used.

  Moreover, although the said embodiment demonstrated the case where the wavelength of the laser beam inject | emitted from three semiconductor lasers (221a, 221b, 221c) was the same, it is not limited to this, Three semiconductor lasers (221a, 221b and 221c) may have different wavelengths of laser light.

  In this case, three semiconductor lasers (221a, 221b, 221c) may be turned on simultaneously. However, in this case, instead of the light receiver 350, a light receiver 350A having a light receiving element for each wavelength is used as shown in FIG. 25 as an example. The light receiver 350A includes three band pass filters (BPF1, BPF2, and BPF3) and three light receiving elements (PD1, PD2, and PD3).

  The bandpass filter BPF1 is a narrowband bandpass filter having the same center wavelength as the wavelength λ1 of the laser light emitted from the semiconductor laser 221a, and the bandpass filter BPF2 is the wavelength λ2 of the laser light emitted from the semiconductor laser 221b. The bandpass filter BPF3 is a narrowband bandpass filter having the same center wavelength as the wavelength λ3 of the laser light emitted from the semiconductor laser 221c.

  The light receiving element PD1 receives the light beam transmitted through the bandpass filter BPF1, the light receiving element PD2 receives the light beam transmitted through the bandpass filter BPF2, and the light receiving element PD3 receives the light beam transmitted through the bandpass filter BPF3. .

  In this case, it is possible to speed up the acquisition of the monitoring data in the sensing control device 300.

  Further, in this case, instead of the three band pass filters (BPF1, BPF2, and BPF3), a diffraction grating 351 may be used as shown in FIG. 26 as an example, and as shown in FIG. 27 as an example. As described above, a prism 352 may be used.

  In this case, a tunable laser capable of changing the wavelength of the emitted light beam may be used instead of the three semiconductor lasers (221a, 221b, 221c). As the wavelength tunable laser, a distributed feedback (DFB) laser, a distributed Bragg reflection (DBR) laser, a wavelength tunable laser having a Littrow configuration, or the like can be used, but a DFB laser or DBR laser capable of current control and temperature control. Is preferred. At this time, the light of wavelength λ1 emitted from the wavelength tunable laser is guided to the light deflection unit 240a, the light of wavelength λ2 is guided to the light deflection unit 240b, and the light of wavelength λ3 is guided to the light deflection unit 240c. It will have an optical system.

  Moreover, although the said embodiment demonstrated the case where the light deflection | deviation element 240 had three light deflection | deviation units stacked | stacked on the Z-axis direction, it is not limited to this. For example, if the light deflection element 240 has four or more light deflection units stacked in the Z-axis direction and the groove periods of the gratings in each light deflection unit are different from each other, a wider range can be sensed. .

  Moreover, although the said embodiment demonstrated the case where two area | regions (250a, 250b) where the direction of the spontaneous polarization in the periodic polarization inversion structure 250 was mutually opposite was a prism shape, it is not limited to this. In short, it is sufficient that light can be deflected in the plane of the optical waveguide in accordance with the applied voltage.

  Moreover, although the said embodiment demonstrated the case where the applied voltage to the upper electrode 247 was -150 [V]-+150 [V], it is not limited to this. The applied voltage to the upper electrode 247 may be set according to the characteristics of the periodically poled structure 250 and the necessary deflection angle.

  In the above embodiment, the case of Λ1 = 500 nm, Λ2 = 420 nm, and Λ3 = 350 nm has been described. However, the present invention is not limited to this. It can be set according to the required deflection angle (deflection angle) in the XZ plane.

  In the above embodiment, as shown in FIG. 28 as an example, a grating 261 is provided separately from the grating 260 at the −Y side end of the + Z side surface of the core layer 245 of each optical deflection unit. Also good.

  In this case, as shown in FIG. 29 as an example, the light emitted from the three light sources (221a, 221b, 221c) is converted into the corresponding coupling lens (223a, 223b, 223c) and the condensing lens (225a, 225b and 225c) to be incident on the grating 261 of the corresponding optical deflection unit and coupled to the optical waveguide.

  Moreover, although the said embodiment demonstrated the case where the front monitoring apparatus 10 was provided with one laser radar 20, it is not limited to this. A plurality of laser radars 20 may be provided according to the size of the vehicle, the monitoring area, and the like.

  Moreover, although the said embodiment demonstrated the case where the laser radar 20 was used for the front monitoring apparatus 10 which monitors the advancing direction (front) of a vehicle, it is not limited to this. For example, you may use for the apparatus which monitors the back of a vehicle.

  Furthermore, the laser radar 20 can also be used for sensing devices other than those for in-vehicle use. In this case, main controller 40 outputs alarm information corresponding to the purpose of sensing.

  The laser radar 20 can also be used for applications other than the sensing device (for example, a measuring device).

  The light deflection element 240 can also be used for applications other than laser radar (for example, medical devices).

  As described above, the optical deflection element of the present invention can be easily miniaturized and is suitable for obtaining a large deflection angle in two directions. The laser apparatus of the present invention is small and suitable for greatly changing the laser beam emission angle two-dimensionally. Further, the sensing device of the present invention is suitable for sensing a small and wide range without incurring an increase in cost.

  DESCRIPTION OF SYMBOLS 1 ... Vehicle, 10 ... Forward monitoring apparatus (sensing apparatus), 20 ... Laser radar, 40 ... Main control apparatus (part of monitoring control apparatus), 50 ... Memory, 60 ... Voice / alarm generating apparatus (one of the monitoring control apparatus) Part), 221a to 221c ... semiconductor laser (laser light source), 230 ... voltage control device, 240 ... light deflection element, 240a, 240b, 240c ... light deflection unit, 250 ... periodic polarization reversal structure (first deflection part) , 260... Grating (second deflection unit), 300... Sensing control device (light source control device, signal processing device).

JP 58-125023 A JP 58-130327 A JP 2000-330143 A

Returning to FIG. 7, the upper clad layer 246 is a Ta ₂ O ₅ layer having a thickness of 1 μm, and is formed on the + Z side of the periodically poled structure 250 in the core layer 245.

The lower cladding layer 244 is a Ta ₂ O ₅ layer having a thickness of 1 μm, and is formed on the −Z side of the core layer 245.

Claims (15)

  A light incident part, a first deflecting part for deflecting light through the light incident part in a first plane in accordance with an applied voltage, and light traveling through the first deflecting part in the traveling direction of the light And a plurality of optical deflection units including a second deflecting unit including a grating that deflects in a second plane orthogonal to the first plane, the optical deflection units being stacked in a direction orthogonal to the first plane. Optical deflecting elements having different groove periods of the gratings in the optical deflecting unit. In the plurality of light deflection units, when no voltage is applied to each first deflection unit, or when the same voltage is applied,
The optical path of the light which passes each 1st deflection | deviation part in these optical deflection units, when seeing from the direction orthogonal to the said 1st surface, is mutually substantially corresponded to Claim 1 characterized by the above-mentioned. The light deflection element described.   3. The optical deflection element according to claim 1, wherein in each of the optical deflection units, the first deflection unit and the second deflection unit are arranged on the same substrate.   4. The light according to claim 1, wherein the first deflecting unit includes a structure having a periodically poled structure and an electrode for applying a voltage to the structure. Deflection element.   In each said light deflection | deviation unit, the grating different from the grating of a said 2nd deflection | deviation part is formed in the surface of the said light-incidence part, The Claim 1 characterized by the above-mentioned. Optical deflection element. The light deflection element according to any one of claims 1 to 5,
A plurality of laser light sources for emitting light respectively incident on a plurality of light deflection units of the light deflection element;
And a voltage control device that controls a voltage applied to each first deflection unit of the plurality of light deflection units.   The laser apparatus according to claim 6, further comprising an optical system that guides a plurality of lights emitted from the plurality of laser light sources to a light incident portion of a corresponding light deflection unit.   The laser apparatus according to claim 6, wherein the plurality of laser light sources emit light having the same wavelength.   The laser apparatus according to claim 8, further comprising a light source control device that sequentially turns on the plurality of laser light sources one by one.   The laser apparatus according to claim 6, wherein the plurality of laser light sources emit light having different wavelengths.   The laser device according to claim 10, further comprising a light source control device that simultaneously turns on the plurality of laser light sources. The laser device according to any one of claims 6 to 11,
A light receiver that receives light emitted from the laser device and reflected by an object;
A signal processing apparatus comprising: a signal processing device that obtains positional information of the object based on an emission direction of light from the laser device and an output signal of the light receiver.   The sensing device according to claim 12, further comprising a display device that displays position information of the object.   The sensing device according to claim 12 or 13, further comprising a memory for storing position information of the object. Mounted on the vehicle,
The sensing device according to any one of claims 12 to 14, further comprising a monitoring control device that outputs alarm information when it is determined that there is a danger based on position information of the object.