JP2019003079A - Light deflector, drawing device, illumination device, obstruction detection device, and light deflection method - Google Patents

Abstract

To make it possible to realize a light deflection technique using a periodically polarization-reversed structure.SOLUTION: A diffraction grating generated in a polarization-reversed region Sa, to which light is made incident first among polarization-reversed regions Sa, Sa, Sa, deflects light L incident from an X direction by Bragg diffraction. Further, a diffraction grating generated in a polarization-reversed region Sa, to which the light L is made incident at the Ma-th time, deflects by Bragg diffraction the light L that was deflected by Bragg diffraction by a diffraction grating generated in a polarization-reversed region Sa, to which the light L is made incidence at the (Ma-1)-th time. Thus, the deflection angle of the light L to one side can be adjusted by changing the number of polarization-reversed regions Sa, Sa, Sa, where a diffraction grating is generated, counted from the first region in the order in which the light L passes.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an optical deflection technique for deflecting light using an electro-optic crystal substrate having a periodically poled structure.

  Non-Patent Document 1 describes an optical deflector that vibrates a micromirror using MEMS (Micro Electro Mechanical Systems) technology and deflects laser light incident on the micromirror. Such an optical deflector is deflected by a vibrating mirror that vibrates mechanically, so that the deflection speed is slow, and since it uses reflection by a micromirror, the laser power resistance is low. For this reason, there is a limit to an optical deflector that vibrates a micromirror by MEMS technology for use in deflecting high-power laser light at high speed. Therefore, an optical deflector that can be used for such applications has been desired.

  On the other hand, Non-Patent Document 2 discloses an electro-optic deflector using an electro-optic effect. The electro-optic deflector creates a prism-shaped domain-inverted part inside the electro-optic crystal and refracts the light by refracting light by the difference in refractive index between the domain-inverted part and the non-inverted part generated by applying a voltage. To deflect. Therefore, since the deflection speed is high and the light transmission type configuration is adopted, the laser power resistance is high. However, there is a problem that the angle at which light can be deflected is small.

Non-Patent Document 3 discloses a Bragg deflector using an electro-optic crystal substrate having a periodically poled structure composed of lithium niobate (LiNbO ₃ ). The Bragg deflector includes an electro-optic crystal substrate, a signal electrode provided on one main surface of the electro-optic crystal substrate, and a common electrode provided on the other main surface of the electro-optic crystal substrate. The signal electrode is formed parallel to the light traveling direction, and when a voltage is applied to the signal electrode, a periodic refractive index distribution is generated in the electro-optic crystal substrate between the signal electrode and the common electrode, and a diffraction grating is generated. Is done. Such a Bragg deflector is characterized by high deflection speed and high laser power resistance. However, there is a problem that the angle at which the light can be deflected is small, only selectively performing whether the light is deflected or not.

Ulrich Hofmann, etc, “High-Q MEMS Resonators for Laser Beam Scanning Displays”, Micromachines 2012, 3, 509-528; doi: 10.3390 / mi3020509 Y. Zuo, etc, “Bulk electro-optic deflector-based switches”, APPLIED OPTICS, Vol. 46, No. 16, pp 3323-3331, 1 June 2007 Harald Gnewuch, etc, “Nanosecond Response of Bragg Deflectors in Periodically Poled LiNbO3”, IEEE PHOTONICS TECHNOLOGY LETTERS, VOL. 10, NO. 12, DECEMBER 1998

  As described above, although the technique using the periodically poled structure has the possibility of being used for the purpose of deflecting high-power laser light at high speed, it is difficult to ensure the deflection angle.

  The present invention has been made in view of the above problems, and provides a technique that enables high-definition laser light to be deflected at a high speed by using a periodically poled structure while ensuring a deflection angle. Objective.

  The optical deflector according to the present invention is an optical deflector that deflects light incident from the traveling direction, and each has a periodic polarization reversal structure in which areas in which the directions of polarization are reversed are periodically arranged. A multistage deflecting element having one deflection region of Na (Na is an integer of 2 or more) passing in order, and an electrode having Na one deflection electrode provided corresponding to the Na one deflection region Each of the one deflection regions includes a diffraction grating that diffracts light in a direction inclined to one side with respect to the traveling direction when a voltage is applied to the corresponding one deflection electrode. The diffraction grating generated in the first deflection region where light enters first among the Na one deflection regions is deflected by Bragg diffraction, and Ma (Ma Is an integer greater than 2 and less than Na) There diffraction grating produced in one deflecting region the incident is deflected by Bragg diffraction of light diffraction grating is deflected by a Bragg diffraction generated on one deflecting region for incident light to (Ma-1) -th.

  The light deflection method according to the present invention is a light deflection method for deflecting light incident from the traveling direction, and each has a periodic polarization reversal structure in which areas in which the directions of polarization are reversed are periodically arranged. The step of causing light to enter from the traveling direction with respect to one Na deflection area (Na is an integer of 2 or more) that passes through in sequence, and Na pieces of Na provided corresponding to the Na one deflection area And a step of controlling a voltage applied to the deflection electrode, and each of the deflection areas emits light in a direction inclined to one side with respect to the traveling direction when a voltage is applied to the corresponding one deflection electrode. Is generated in the periodic polarization reversal structure, and the diffraction grating generated in the first deflection region where light enters first among the Na one deflection regions is incident from the traveling direction. The light is deflected by Bragg diffraction, and Ma ( (a is an integer greater than or equal to 2 and less than or equal to Na) The diffraction grating generated in the first deflection area where the light is incident is the (Ma-1) diffraction grating generated in the first deflection area where the light is incident. Light deflected by Bragg diffraction is deflected by Bragg diffraction.

  In the present invention thus configured (optical deflector, optical deflection method), Na one deflection regions each having a periodically poled structure in which areas in which the directions of polarization are reversed are periodically arranged are provided, Light sequentially passes through the Na one deflection region. Further, Na one deflection electrodes are provided corresponding to Na one deflection regions. Each one deflection region generates a diffraction grating in the periodically poled structure that diffracts light in a direction inclined to one side with respect to the traveling direction when a voltage is applied to the corresponding one deflection electrode. .

  In particular, the Na one deflection region is configured to be able to deflect light by Bragg diffraction in order. That is, the diffraction grating generated in the first deflection region where light enters first among the Na one deflection regions deflects the light incident from the traveling direction by Bragg diffraction. Further, the diffraction grating generated in the first deflection area where light enters Ma (Ma is an integer of 2 or more and Na or less) is generated in the first deflection area where light enters (Ma-1) th. The light deflected by Bragg diffraction is deflected by Bragg diffraction. Therefore, by increasing the number of the deflection regions for generating the diffraction grating, counted from the beginning of the light passing sequence, the deflection angle of the light toward one side can be increased.

  As described above, according to the present invention, since the electro-optic effect of the periodically poled structure is used, high-speed deflection is possible, and since a light transmission type structure using the periodically poled structure is adopted, high optical power resistance is also achieved. realizable. In addition, the deflection angle can be secured by arranging the deflection regions in multiple stages. In this way, by using the periodically poled structure, it is possible to secure a deflection angle while enabling high-speed deflection of high-power laser light.

  The multistage deflection element further includes Nb (Nb is an integer of 2 or more) other deflection regions each having a periodically poled structure, and the electrode portion is provided corresponding to the Nb other deflection regions. Nb number of other deflection electrodes, and each of the other deflection regions diffracts light in a direction inclined to the other side when a voltage is applied to the corresponding other deflection electrode. The diffraction grating is generated in the periodically poled structure, and the diffraction grating generated in the other deflection region where the light is incident first among the Nb other deflection regions is configured to receive the light incident from the traveling direction. The diffraction grating which is deflected by Bragg diffraction and is generated in the other deflection region where light enters Mb (Mb is an integer of 2 or more and Nb or less) is used for the other deflection where light enters (Mb-1). Diffraction grating generated in the region is used for Bragg diffraction Ri deflected light to deflect by Bragg diffraction, it may constitute an optical deflector.

  In this configuration, each of the other deflection regions has a diffraction grating that diffracts light in a direction inclined to the other side with respect to the traveling direction in the periodic polarization inversion structure when a voltage is applied to the corresponding other deflection electrode. Generate. In particular, the Nb other deflection regions are configured so as to be able to deflect light by Bragg diffraction in order. That is, among the Nb other deflection regions, the diffraction grating generated in the other deflection region where light enters firstly deflects light incident from the traveling direction by Bragg diffraction. Furthermore, the diffraction grating generated in the other deflection region where light enters Mb (Mb is an integer of 2 or more and Nb or less) th is generated in the other deflection region where light enters (Mb-1) th. The light deflected by Bragg diffraction is deflected by Bragg diffraction. Therefore, by increasing the number of the other deflection regions for generating the diffraction grating, counted from the beginning of the light passing sequence, the deflection angle of the light toward the other side can be increased. Thus, it is possible to realize an optical deflection technique that can secure a deflection angle to both one side and the other side while enabling high-speed deflection of high-power laser light by using the periodic polarization inversion structure.

  Furthermore, the optical deflector may be configured such that the number Na of one deflection area is equal to the number Nb of the other deflection area. In such a configuration, light can be deflected equally in a balanced manner on both the one side and the other side, and the deflection angle can be further increased.

  At this time, various variations are conceivable for the arrangement of the one deflection region and the other deflection region. For example, the optical deflector may be configured such that Nb other deflection regions are arranged after Na one deflection regions in the order in which light passes. Alternatively, the optical deflector may be configured such that one deflection region and the other deflection region are alternately arranged in the order in which light passes.

  Further, the optical deflector may be configured to further include a scanning control unit that controls the voltage applied to the electrode unit to scan the light with the multistage deflection element in the first scanning direction that intersects the traveling direction. good. In such a configuration, it is possible to scan light using a periodically poled structure.

  In addition, it further includes a continuous deflection unit that continuously deflects the light that has passed through the multistage deflection element in the first scanning direction, and the scanning control unit adjusts the deflection angle of the light by the continuous deflection unit, The light deflector may be configured to continuously scan light in the first direction by irradiating light between a plurality of discrete positions where light can be irradiated. In such a configuration, it is possible to realize continuous light scanning by supplementing the discrete light scanning by the multistage deflecting element with the continuous deflection unit.

  Specifically, the continuous deflection unit includes a plurality of prisms through which light sequentially passes and a common electrode provided in common to the plurality of prisms, and the polarization directions of the plurality of prisms are in the order in which the light passes through. Inverted alternately, and the scanning control unit controls the voltage applied to the common electrode, so that the light that has passed through the multistage deflection element is deflected continuously in the first scanning direction by the continuous deflection unit. A vessel may be configured.

  Further, the light deflector may be configured so that the light passage surface of the prism has a shape that is convexly curved in the traveling direction. Thus, vignetting on the light passage surface (prism surface) of the prism can be suppressed.

  Further, the optical deflector may be configured so that the passing surface has a shape in which the deflection angle of each prism is the minimum deflection angle. Thereby, vignetting on the prism surface can be more reliably suppressed.

  Further, in the continuous deflection unit, the optical deflector is arranged such that a plurality of prism groups composed of a plurality of prisms whose polarization directions are alternately reversed in the order in which the light passes are arranged in a direction orthogonal to the traveling direction. May be configured. In such a configuration, since a large number of minute prisms can be arranged in a matrix, the number of refractive surfaces can be increased without increasing the size of the optical deflector. Therefore, since the refraction angle of each refracting surface can be reduced, the voltage applied to the prism (polarization inversion structure) can be set low, and higher-speed light deflection can be achieved.

  In addition, the optical deflector may be configured to further include a scanning deflection unit that deflects light that has passed through the multistage deflection element in a second scanning direction orthogonal to the first scanning direction. This makes it possible to scan light two-dimensionally.

In addition, in the periodic polarization reversal structure of the one deflection region where light enters the I (I is an integer of 1 or more) -th among the Na one deflection regions, the sections are periodically arranged with the period Λ _i and The boundary of the adjacent area is inclined by the angle φ _{i with} respect to the traveling direction, and the following relational expression φ _i = θ _i−1 + arcsin (λ / 2nΛ _i )
n: Refractive index of the crystal constituting the periodically poled structure θ _i-1 : Angle between the light incident on the I-th one deflection region and the traveling direction λ: Light deflection so that the wavelength of the light is satisfied A vessel may be configured. In such a configuration, it is possible to reliably deflect the light incident on the one deflection region by Bragg diffraction.

  Various uses of the above optical deflector are conceivable. For example, by controlling the deflection of the light by the light deflector, the light deflector that deflects the light from the light source, and the position where the light that has passed through the light deflector is irradiated onto the drawing object. A drawing apparatus may be configured that includes a control unit that adjusts and draws a pattern on a drawing target.

  A lighting device comprising a light source unit, the above-described optical deflector that deflects light from the light source unit, and a control unit that irradiates light to an irradiation target by controlling light deflection by the optical deflector is configured. Also good.

  Alternatively, a light source unit, the above-described optical deflector that scans light from the light source unit, a detection unit that detects reflection of the scanned light by an obstacle, and the presence or absence of an obstacle are determined based on the detection result of the detection unit You may comprise an obstacle detection apparatus provided with the control part to perform.

  As described above, according to the present invention, it is possible to secure a deflection angle while enabling high-speed deflection of high-power laser light by using a periodically poled structure.

The perspective view which shows typically the optical deflector which concerns on 1st Embodiment of this invention. The disassembled perspective view which shows typically arrangement | positioning of the several polarization inversion area | region with which the optical deflector of FIG. 1 is provided. The top view which shows typically an example of operation | movement of the optical deflector of FIG. FIG. 4 is a diagram illustrating an example of the operation illustrated in FIG. 3 in a table format. The top view which shows typically the optical deflector which concerns on 2nd Embodiment of this invention. The perspective view which shows typically an example of the continuous deflection | deviation part with which the optical deflector of FIG. 5 is provided. The top view which shows typically the optical deflector which concerns on 3rd Embodiment of this invention. The top view which shows typically the optical deflector which concerns on 4th Embodiment of this invention. The top view which shows typically the optical deflector which concerns on 5th Embodiment of this invention. The figure which shows typically the optical deflector which concerns on 6th Embodiment of this invention. The front view which shows typically schematic structure of one Embodiment of the drawing apparatus provided with the optical deflector which concerns on this invention. The figure which shows typically schematic structure of one Embodiment of the illuminating device provided with the optical deflector which concerns on this invention. The figure which shows typically one Embodiment of the obstruction detection apparatus provided with the optical deflector which concerns on this invention. The figure which shows typically the modification of the optical deflector shown in 2nd Embodiment. The figure which shows typically the modification of the deflector shown in 3rd Embodiment. The contour map of the light intensity distribution which shows an example of the concrete simulation result of this invention.

  FIG. 1 is a perspective view schematically showing an optical deflector according to the first embodiment of the present invention. FIG. 2 is an exploded perspective view schematically showing the arrangement of a plurality of polarization inversion regions provided in the optical deflector of FIG. FIG. 3 is a plan view schematically showing an example of the operation of the optical deflector of FIG. FIG. 4 is a diagram showing an example of the operation shown in FIG. 3 in a table format. 1 to 3 and the following drawings appropriately show an XYZ orthogonal coordinate system in which the traveling direction of the light L incident on the optical deflector 1 is the X direction. In particular, one side in the X direction (traveling side of the light L) is the + X side, the other side in the X direction is the -X side, one side in the Y direction is the + Y side, and the other side in the Y direction is the -Y side. One side in the Z direction is referred to as + Z side, and the other side in the Z direction is referred to as -Z side as appropriate.

  The optical deflector 1 includes a multistage deflection element 2, an electrode section 3 attached to the multistage deflection element 2, a drive section 41 that applies a voltage corresponding to a signal to the electrode section 3, and a drive control section 5 that controls the drive section 41. The light L that has entered while traveling from the −X side to the + X side in the X direction is deflected in the Y direction orthogonal to the X direction.

The multistage deflection element 2 is an electro-optic crystal substrate formed of, for example, lithium niobate (LiNbO ₃ ) single crystal, and in the electro-optic crystal substrate, there are three polarization inversion regions Sa ₁ , Sa ₂ , Sa _3. Is formed. The polarization inversion regions Sa ₁ , Sa ₂ , Sa ₃ are arranged in series in the X direction, and the light L incident on the optical deflector 1 passes through these in order. Incidentally, when there is no need to distinguish between the polarization inversion region _{Sa 1, Sa 2, Sa 3} is collectively referred them appropriately and polarization inversion region Sa. In addition, the periods Λa ₁ , Λa ₂ , Λa ₃ and the inclination angles φa ₁ , φa ₂ , φa _3, etc., which characterize the configurations of the domain-inverted regions Sa ₁ , Sa ₂ , Sa _{3, which} are described later, These are collectively referred to as a period Λa and an inclination angle φa as appropriate.

  The domain-inverted region Sa has a rectangular parallelepiped shape, the light incident surface 22 and the exit surface 23 of the domain-inverted region Sa are parallel to the YZ plane, and one main surface 24 and the other main surface 25 of the domain-inverted region Sa are XY planes. Parallel to The domain-inverted region Sa has a periodically domain-inverted structure in which areas where the directions of polarization are inverted are periodically arranged with a period Λa. That is, in the polarization inversion region Sa, there are a polarization area 26 polarized toward the −Z side (lower side in FIG. 2) in the Z direction and a polarization area 27 polarized toward the + Z side (upper side in FIG. 2) in the Z direction. Alternatingly arranged, each of the polarization sections 26, 27 has a strip-like quadrangular prism shape that is half the width of the period Λa. At this time, the arrangement direction of the polarization sections 26 and 27, in other words, the direction in which the polarization inversion appears periodically is inclined with respect to the Y direction. As a result, the boundary plane 28 between the adjacent polarization sections 26 and 27 is X (In other words, the boundary plane 28 advances toward the + X side in the Y direction as it advances toward the + X side in the X direction, which is the traveling direction of the light L). Thus, it is inclined at an inclination angle φa with respect to the X direction).

The electrode unit 3 includes three signal electrodes Ea ₁ , Ea ₂ , and Ea ₃ that are individually provided corresponding to the _three polarization inversion regions Sa ₁ , Sa ₂ , and Sa ₃ . Each of the signal electrodes Ea ₁ , Ea ₂ , Ea ₃ has a flat plate shape extending in parallel with the Y direction, and is attached to one main surface 24 of the corresponding domain-inverted regions Sa ₁ , Sa ₂ , Sa _3. ing. The electrode unit 3 has a ground electrode Eg provided in common on the other main surface 25 of each of the _three polarization inversion regions Sa ₁ , Sa ₂ , Sa ₃ . Thus, each of the three polarization inversion regions Sa ₁ , Sa ₂ , Sa ₃ is sandwiched between the corresponding signal electrodes Ea ₁ , Ea ₂ , Ea ₃ and the ground electrode Eg.

The drive unit 41 can individually apply a voltage corresponding to a signal to each of the signal electrodes Ea ₁ , Ea ₂ , and Ea ₃ . On the other hand, the drive control unit 5 is a processor in charge of the function of controlling the drive unit 41, and includes a CPU (Central Processing Unit) and a RAM (Random Access Memory). In particular, the drive control unit 5 controls the application of voltages corresponding to the signals to the signal electrodes Ea ₁ , Ea ₂ , and Ea ₃ by the drive unit 41, thereby diffracting the polarization inversion regions Sa ₁ , Sa ₂ , and Sa ₃ . A grating is generated and the deflection direction of the light L is adjusted.

That is, the polarization inversion regions Sa ₁ , Sa ₂ , Sa ₃ receive a voltage corresponding to the signal applied to the corresponding signal electrodes Ea ₁ , Ea ₂ , Ea ₃ , and are Bragg type in each periodic polarization inversion structure. The diffraction grating is generated. The diffraction grating diffracts the light L in a direction inclined to the + Y side in the Y direction with respect to the X direction. Referring to FIG. 3 in detail, the diffraction grating generated in the first-stage polarization inversion region Sa ₁ causes the light L incident parallel to the X direction to be incident on the light L only at a diffraction angle α _1. Diffracted by Bragg diffraction in a direction inclined to the + Y side in the Y direction. The diffraction grating generated in the second-stage polarization inversion region Sa ₂ tilts the light L diffracted by the previous-stage polarization inversion region Sa ₁ toward the + Y side in the Y direction by the diffraction angle α _{2 with} respect to the light L. Diffracted by Bragg diffraction in the specified direction. The diffraction grating generated in the third-stage polarization inversion region Sa ₃ tilts the light L diffracted by the previous-stage polarization inversion region Sa ₂ with respect to the light L by the diffraction angle α ₃ toward the + Y side in the Y direction. Diffracted by Bragg diffraction in the specified direction.

Accordingly, as shown in FIG. 4, the signal electrodes Ea _1, Ea _2, when no voltage is applied which corresponds to one to signal also the Ea _3, the light has been incident on the parallel multistage deflecting element 2 in the X direction L Passes through the polarization inversion regions Sa ₁ , Sa ₂ , Sa ₃ without being diffracted, and is emitted in a direction Da ₀ parallel to the X direction. When a voltage corresponding to a signal is applied only to the first-stage signal electrode Ea ₁ , the light L incident on the multistage deflection element 2 in parallel to the X direction is diffracted by the polarization inversion region Sa ₁ , It is deflected in a direction Da ₁ inclined to the + Y side of the Y direction with respect to the direction. When a voltage corresponding to a signal is applied only to the _first and _second stage signal electrodes Ea ₁ and Ea ₂ , the light L incident on the multistage deflection element 2 parallel to the X direction is converted into the polarization inversion regions Sa ₁ , It is diffracted by Sa ₂ and deflected in a direction Da ₂ that is inclined further to the + Y side in the Y direction with respect to the X direction than the direction Da ₁ . When a voltage corresponding to a signal is applied to any of the _first to third stage signal electrodes Ea ₁ , Ea ₂ , Ea ₃ , the light L incident on the multistage deflection element 2 in parallel to the X direction is polarized. is diffracted by the inversion region _{Sa 1, Sa 2, Sa 3} , is deflected in a direction Da ₃ inclined to the + Y side of Y-direction relative to the further X-direction than in the direction Da _2. Therefore, the drive controller 5 changes the deflection direction of the light L by controlling the application of voltages corresponding to the signals to the signal electrodes Ea ₁ , Ea ₂ , and Ea ₃ , and changes the light L to + Y in the Y direction. Can be scanned on both the side and the -Y side.

As described above, in the optical deflector 1 according to the first embodiment, Na polarization inversion regions Sa ₁ and Sa ₂ each having a periodically poled structure in which the polarization areas 26 and 27 in which the polarization directions are inverted are periodically arranged. , Sa ₃ are provided, and the light L sequentially passes through the Na polarization inversion regions Sa ₁ , Sa ₂ , Sa ₃ . Here, Na is an integer of 2 or more, and is “3” in the first embodiment. Further, Na signal electrodes Ea ₁ , Ea ₂ , Ea ₃ are provided corresponding to the Na polarization inversion regions Sa ₁ , Sa ₂ , Sa ₃ . Each domain-inverted regions _{Sa 1, Sa 2, Sa 3} is the voltage corresponding to the signal to the corresponding signal electrodes _{Ea 1, Ea 2, Ea 3} is applied, it is inclined to the X-direction + Y side A diffraction grating that diffracts the light L in the direction is generated in the periodically poled structure.

In particular, the Na polarization inversion regions Sa ₁ , Sa ₂ , Sa ₃ are configured so that the light L can be deflected by Bragg diffraction in order. That is, among the Na polarization inversion regions Sa ₁ , Sa ₂ , Sa ₃ , the diffraction grating generated in the polarization inversion region Sa ₁ where light is incident _first is Bragg diffraction of the light L incident from the X direction. To deflect. Furthermore, the diffraction grating generated in the polarization inversion region Sa _Ma where the light L is incident on the Math is Bragg is the diffraction grating generated in the polarization inversion region Sa _Ma-1 where the light L is incident on the (Ma-1) th. Light L deflected by diffraction is deflected by Bragg diffraction. Here, Ma is an integer of 2 or more and Na or less, and is “2” or “3” in the first embodiment. Therefore, the deflection angle of the light L toward the + Y side is increased by increasing the number of polarization inversion regions Sa ₁ , Sa ₂ , Sa ₃ for generating the diffraction grating, counted from the beginning of the light L passing sequence. Can do.

As described above, according to the first embodiment, high-speed deflection is possible because the electro-optic effect of the periodically poled structure is used, and high light power is achieved because the light transmission type structure using the periodically poled structure is employed. Resistance can also be realized. In addition, by arranging the polarization inversion regions Sa ₁ , Sa ₂ , Sa ₃ in multiple stages, a deflection angle can be secured. In this way, by using the periodically poled structure, it is possible to secure a deflection angle while enabling high-speed deflection of high-power laser light.

Further, the drive control unit 5 controls the voltages corresponding to the signals applied to the signal electrodes Ea ₁ , Ea ₂ , and Ea ₃ , thereby scanning the light L by the multistage deflection element 2 in the Y direction orthogonal to the X direction. To do. In this way, it is possible to scan the light L using the periodically poled structure.

  Subsequently, an embodiment different from the above embodiment will be described. At this time, differences from the above-described embodiment will be mainly described, and common portions will be denoted by corresponding reference numerals, and description thereof will be omitted as appropriate. However, it goes without saying that the same effect can be obtained by providing the configuration common to the above embodiment.

  FIG. 5 is a plan view schematically showing an optical deflector according to the second embodiment of the present invention. FIG. 6 is a perspective view schematically showing an example of a continuous deflection unit provided in the optical deflector of FIG. The second embodiment is different from the first embodiment in that the optical deflector 1 includes a continuous deflection unit 6 provided in a subsequent stage of the multistage deflection element 2 and a drive unit 42 that drives the continuous deflection unit 6. It is. That is, the light L that has passed through the multistage deflection element 2 is further irradiated through the continuous deflection unit 6 and then irradiated onto the irradiation object J. At this time, the continuous deflection unit 6 can deflect the light L incident from the multistage deflection element 2 in the Y direction.

  That is, the continuous deflection unit 6 includes a continuous deflection element 61 that is an electro-optic crystal substrate formed of, for example, a lithium niobate single crystal. The continuous deflection element 61 has a rectangular parallelepiped shape, the light incident surface 62 and the emission surface 63 of the continuous deflection element 61 are parallel to the YZ plane, and the one main surface 64 and the other main surface 65 of the continuous deflection element 61 are XY. Parallel to the plane. In this continuous deflection element 61, prisms 66 and 67 (triangular prisms in this example) whose polarization directions are reversed are alternately arranged in series in the X direction (in other words, the light L passing sequence). The polarization of the prism 66 faces the + Z side (upper side in FIG. 6) in the Z direction, the polarization of the prism 67 faces the -Z side (lower side in FIG. 6) in the Z direction, and the prism surfaces 68 of the adjacent prisms 66 and 67 respectively. Are in contact with each other.

  Further, the continuous deflection unit 6 has an electrode unit 69 attached to the continuous deflection element 61. The electrode portion 69 includes a common signal electrode 691 attached to one main surface 64 of the continuous deflection element 61 and a ground electrode 692 attached to the other main surface 65 of the continuous deflection element 61. Each of the common signal electrode 691 and the ground electrode 692 is provided in common to the plurality of prisms 66 and 67, and each prism 66 and 67 is sandwiched between the common signal electrode 691 and the ground electrode 692.

The driving unit 42 can apply a voltage corresponding to the signal to the common signal electrode 691. In the state where no voltage corresponding to the signal from the drive unit 42 to the common signal electrode 691 is applied, the prisms 66 and 67 have the same refractive index. Therefore, the light L emitted from the multistage deflection element 2 passes through the continuous deflection element 61 without being deflected by the continuous deflection element 61 and is irradiated to the irradiation object J. That is, according to the deflection directions Da ₀ , Da ₁ , Da ₂ , Da ₃ by the multistage deflection element 2, the irradiation positions Pa ₀ , Pa ₁ , Pa ₂ , Pa ₃ of the irradiation target J arranged in the Y direction are arranged. Either one is irradiated with light L.

On the other hand, when a voltage corresponding to the signal is applied from the driving unit 42 to the common signal electrode 691, a difference in refractive index corresponding to the magnitude of the voltage corresponding to the signal is generated between the prisms 66 and 67. Therefore, the light L emitted from the multistage deflecting element 2 is deflected by the continuous deflecting element 61 and then irradiated to the irradiation object J. At this time, the drive unit 42 can continuously change the angle at which the continuous deflection element 61 deflects the light L by changing the magnitude of the voltage corresponding to the signal to the common signal electrode 691. Therefore, the light L can also be irradiated to the ranges Ra ₁ , Ra ₂ , Ra ₃ between the irradiation positions Pa ₀ , Pa ₁ , Pa ₂ , Pa _3, respectively. In such a configuration, the drive control unit 5 controls the voltage corresponding to the signal applied by the drive unit 41 and the drive unit 42 to continuously emit the light L in the Y direction in a range including the irradiation positions Pa _{0 to} Pa _3. Can be scanned.

As described above, the optical deflector 1 according to the second embodiment is provided with the continuous deflecting unit 6 that continuously deflects the light L that has passed through the multistage deflecting element 2 in the Y direction. Then, the drive control unit 5 adjusts the deflection angle of the light L by the continuous deflection unit 6 and a plurality of discrete irradiation positions Pa ₀ , Pa ₁ , Pa ₂ , which can be irradiated with the light L by the multistage deflection element ₂ . By irradiating the light L during Pa ₃ , the light L is continuously scanned in the Y direction. In such a configuration, it is possible to realize continuous light scanning by supplementing the discrete light scanning by the multistage deflecting element 2 with the continuous deflection unit 6.

  FIG. 7 is a plan view schematically showing an optical deflector according to the third embodiment of the present invention. The third embodiment differs from the second embodiment in the specific configuration of the continuous deflection unit 6 provided in the optical deflector 1. That is, the prism surfaces 68 of the prisms 66 and 67 constituting the continuous deflection element 61 of the continuous deflection unit 6 have a curved shape that is convex in the light traveling direction, that is, in the X direction. By finishing the prism surface 68 in such a shape, vignetting on the prism surface 68 (the surface through which the light L passes) can be suppressed. Particularly in the third embodiment, the prism surface 68 has a shape in which the declination of each of the prisms 66 and 67 is the minimum declination. This makes it possible to more reliably suppress vignetting on the prism surface 68.

FIG. 8 is a plan view schematically showing an optical deflector according to the fourth embodiment of the present invention. The fourth embodiment is different from the above-described embodiment in that the multistage deflection element 2 has three polarization inversion regions Sb ₁ , Sb ₂ , Sb in addition to the three polarization inversion regions Sa ₁ , Sa ₂ , Sa ₃ described above. ₃ is a point. That is, in the multistage deflection element 2, the polarization inversion regions Sa ₁ , Sa ₂ , Sa ₃ , Sb ₁ , Sb ₂ , Sb ₃ are arranged in series in this order. In the case where the domain-inverted regions Sb ₁ , Sb ₂ , and Sb ₃ are not distinguished, these are collectively referred to as domain-inverted regions Sb as appropriate. Further, periods Λb ₁ , Λb ₂ , Λb _3, etc., which characterize the configuration of each of the domain-inverted regions Sb ₁ , Sb ₂ , Sb ₃ , are collectively referred to as a period Λb as appropriate unless they are distinguished from each other.

  The domain-inverted region Sb is formed in an electro-optic crystal substrate that is a single crystal of lithium niobate, and has a rectangular parallelepiped outer shape similar to that of the domain-inverted region Sa. This domain-inverted region Sb has a periodic domain-inverted structure in which areas in which the directions of polarization are inverted are periodically arranged with a period Λb. At this time, the direction in which the boundary plane 28 of each section where the directions of polarization are reversed is inclined with respect to the X direction is opposite between the polarization inversion region Sa and the polarization inversion region Sb. That is, in the domain-inverted region Sa, the boundary plane 28 is inclined on the + Y side in the Y direction with respect to the X direction, whereas in the domain-inverted region Sb, on the −Y side in the Y direction with respect to the X direction. The boundary plane 28 is inclined.

The electrode unit 3 includes three signal electrodes Eb ₁ , Eb ₂ , and Eb ₃ that are individually provided corresponding to the _three polarization inversion regions Sb ₁ , Sb ₂ , and Sb ₃ . Each of the signal electrodes Eb ₁ , Eb ₂ , Eb ₃ has a flat plate shape extending in parallel with the Y direction, and is attached to one main surface of the corresponding polarization inversion regions Sb ₁ , Sb ₂ , Sb _3. Yes. The ground electrode Eg of the electrode unit 3 is provided in common on the other main surface of each of the _three polarization inversion regions Sb ₁ , Sb ₂ , Sb ₃ . Thus, each of the three polarization inversion regions Sb ₁ , Sb ₂ , Sb ₃ is sandwiched between the corresponding signal electrodes Eb ₁ , Eb ₂ , Eb ₃ and the ground electrode Eg.

The drive unit 41 can individually apply a voltage corresponding to a signal to each of the signal electrodes Ea ₁ , Ea ₂ , Ea ₃ , Eb ₁ , Eb ₂ , Eb ₃ . And the drive control part 5 controls the application of the voltage corresponding to the signal to the signal electrodes Ea ₁ , Ea ₂ , Ea ₃ , Eb ₁ , Eb ₂ , Eb ₃ by the drive part 41, and thereby the polarization inversion region Sa. ₁ , Sa ₂ , Sa ₃ , Sb ₁ , Sb ₂ , Sb ₃ , a diffraction grating is generated, and the deflection direction of the light L is adjusted. Since the deflection of the light L by the polarization inversion regions Sa ₁ , Sa ₂ , Sa ₃ is the same as described above, the description thereof is omitted.

Inverted regions _{Sb 1, Sb 2, Sb 3} is subjected to a voltage corresponding to the signal to the corresponding signal electrodes _{Eb 1, Eb 2, Eb 3} , Bragg diffraction of the respective periodic polarization inversion structure Generate a grid. The diffraction grating diffracts the light L in a direction inclined to the −Y side in the Y direction with respect to the X direction. In other words, the diffraction grating generated in the first-stage polarization inversion region Sb ₁ causes the light L that has passed through the polarization inversion regions Sa ₁ , Sa ₂ , Sa ₃ and entered in parallel in the X direction to the light L. diffracted by Bragg diffraction in the direction inclined by the diffraction angle beta ₁ in the Y direction to the -Y side against. The diffraction grating generated in the second-stage polarization inversion region Sb ₂ causes the light L diffracted by the previous-stage polarization inversion region Sb ₁ to the −Y side in the Y direction by the diffraction angle β _{2 with} respect to the light L. Diffracted by Bragg diffraction in an inclined direction. The diffraction grating generated in the third-stage polarization inversion region Sb ₃ causes the light L diffracted by the previous-stage polarization inversion region Sb ₂ to move toward the −Y side in the Y direction by the diffraction angle β _{3 with} respect to the light L. Diffracted by Bragg diffraction in an inclined direction.

Therefore, the light L can be selectively deflected in any one of the directions Db _{0 to} Db ₃ by controlling the application of the voltage corresponding to the signal to the signal electrodes Eb ₁ , Eb ₂ , Eb ₃ . When the light L is deflected to the −Y side in the Y direction by the polarization inversion region Sb, a voltage corresponding to the signal is applied to the signal electrodes Ea ₁ , Ea ₂ , Ea ₃ attached to the polarization inversion region Sa. Not. Similarly, when the light L is deflected to the + Y side in the Y direction by the polarization inversion region Sa, a voltage corresponding to the signal is applied to the signal electrodes Eb ₁ , Eb ₂ , Eb ₃ attached to the polarization inversion region Sb. Not.

Thus, in the fourth embodiment, the multistage deflection element 2 further includes Nb polarization inversion regions Sb ₁ , Sb ₂ , and Sb ₃ each having a periodic polarization inversion structure, and the light L has Nb polarization inversion regions. It passes through Sb ₁ , Sb ₂ and Sb ₃ in order. Here, Nb is an integer equal to or greater than 2, and is “3” in the fourth embodiment. The electrode unit 3 further includes Nb signal electrodes Eb ₁ , Eb ₂ , Eb ₃ provided corresponding to the Nb polarization inversion regions Sb ₁ , Sb ₂ , Sb ₃ . Each polarization inversion region Sb ₁ , Sb ₂ , Sb ₃ is inclined to the −Y side with respect to the X direction when a voltage corresponding to the signal is applied to the corresponding signal electrodes Eb ₁ , Eb ₂ , Eb _3. A diffraction grating that diffracts the light L in the selected direction is generated in the periodically poled structure.

In particular, the Nb polarization inversion regions Sb ₁ , Sb ₂ , Sb ₃ are configured so as to be able to deflect the light L by Bragg diffraction in order. That is, among the Nb polarization inversion regions Sb ₁ , Sb ₂ , Sb ₃ , the diffraction grating generated in the polarization inversion region Sb ₁ where the light L is incident first Braggs the light L incident from the X direction. Deflection by diffraction. Further, the diffraction grating generated in the polarization inversion region Sb _Mb where the light L is incident on the Mb-th is Bragg is the diffraction grating generated in the polarization inversion region Sb _Mb-1 where the light L is incident on the (Mb-1) -th. Light L deflected by diffraction is deflected by Bragg diffraction. Here, Mb is an integer of 2 or more and Nb or less, and is “2” or “3” in the fourth embodiment. Therefore, by increasing the number of polarization inversion regions Sb ₁ , Sb ₂ , Sb ₃ for generating a diffraction grating, counted from the beginning of the light L passing sequence, the deflection angle of the light L toward the −Y side is increased. be able to. In this way, it is possible to realize an optical deflection technique that can secure a deflection angle of the light L to both the + Y side and the -Y side while enabling high-speed deflection of high-power laser light by using the periodically poled structure. It has become.

Furthermore, the number of polarization inversion regions Sa ₁ , Sa ₂ , Sa ₃ that deflect the light L toward the + Y side is equal to the number of polarization inversion regions Sb ₁ , Sb ₂ , Sb ₃ that deflect the light L toward the −Y side. . As a result, the light L can be deflected evenly with good balance to both the + Y side and the −Y side, and the deflection angle can be further increased.

FIG. 9 is a plan view schematically showing an optical deflector according to the fifth embodiment of the present invention. The fifth embodiment differs from the fourth embodiment in the arrangement relationship between the _three domain-inverted regions Sa ₁ , Sa ₂ , Sa ₃ and the three domain-inverted regions Sb ₁ , Sb ₂ , Sb _3. . That is, in the fourth embodiment, the three polarization inversion regions Sb ₁ , Sb ₂ , and Sb ₃ are arranged in the subsequent stage of the polarization inversion regions Sa ₁ , Sa ₂ , Sa _{3 in} the light L passing sequence. On the other hand, in the fifth embodiment, the polarization inversion regions Sa and the polarization inversion regions Sb are alternately arranged in the light L passing sequence.

Even in such a configuration, the drive control unit 5 applies the voltage corresponding to the signal to the signal electrodes Ea ₁ , Ea ₂ , Ea ₃ , Eb ₁ , Eb ₂ , Eb ₃ by the drive unit 41 as in the fourth embodiment. To generate a diffraction grating in the polarization inversion regions Sa ₁ , Sa ₂ , Sa ₃ , Sb ₁ , Sb ₂ , Sb ₃ , and adjust the deflection direction of the light L on both the + Y side and the −Y side. can do. In particular, the diffraction grating that deflects light toward the + Y side and the −Y side appears and disperses alternately on the optical axis as compared with the fourth embodiment, so there is no difficulty in the optical system arranged at the subsequent stage of the optical axis. , + Y side, −Y side.

Furthermore, the number of polarization inversion regions Sa ₁ , Sa ₂ , Sa ₃ that deflect the light L toward the + Y side is equal to the number of polarization inversion regions Sb ₁ , Sb ₂ , Sb ₃ that deflect the light L toward the −Y side. . As a result, the light L can be deflected evenly in a well-balanced manner to both the + Y side and the −Y side.

  FIG. 10 is a diagram schematically showing an optical deflector according to the sixth embodiment of the present invention. The optical deflector 1 according to the sixth embodiment includes a polygon mirror PM that deflects the light L that has passed through the multistage deflection element 2, and a drive unit 43 that rotationally drives the polygon mirror PM. The polygon mirror PM is rotatable in a rotation direction C that is orthogonal to the Y direction. In this optical deflector 1, the drive control unit 5 controls the drive unit 41 to scan the light L in the Y direction (main scanning direction) with the multistage deflection element 2 (main scanning). The main scanning in the Y direction may be continuously performed by the multistage deflection element 2 and the continuous deflection unit 6 as shown in the second embodiment.

  Further, the drive control unit 5 displaces the light L scanned by the multistage deflection element 2 in the rotation direction C (sub-scanning direction) by rotating the polygon mirror PM in the rotation direction C in synchronization with the main scanning of the light L. (Sub-scan). In such a configuration, the multi-stage deflecting element 2 scans the light L in the main scanning direction Y (first scanning direction), and deflects the light L in the sub-scanning direction C (second scanning direction) by the polygon mirror PM. The light L can be scanned two-dimensionally.

  By the way, various uses of the optical deflector 1 exemplified through the first to sixth embodiments are conceivable. Then, the specific example of the use of the optical deflector 1 is shown suitably. However, the use of the optical deflector 1 is not limited to the following devices, and can be applied to other devices.

  FIG. 11 is a front view schematically showing a schematic configuration of an embodiment of a drawing apparatus having an optical deflector according to the present invention. The drawing device 7 is a device that draws a pattern by irradiating light onto the upper surface of the substrate W on which a layer of a photosensitive material such as a resist is formed. The substrate W may be any of various substrates such as a semiconductor substrate, a printed substrate, a color filter substrate, a glass substrate for a flat panel display provided in a liquid crystal display device or a plasma display device, and an optical disk substrate. In the illustrated example, the upper layer pattern is drawn so as to overlap the lower layer pattern formed on the upper surface of the circular semiconductor substrate.

  The drawing device 7 includes a main body inside formed by attaching cover panels (not shown) to the ceiling surface and the peripheral surface of the skeleton composed of the main body frame 701, and a main body exterior that is outside the main body frame 701. It has a configuration in which various components are arranged. The inside of the main body of the drawing apparatus 7 is divided into a processing area 702 and a delivery area 703. Of these areas, a stage 71, a stage moving mechanism 72, and an optical head 73 are mainly arranged in the processing area 702. On the other hand, in the transfer area 703, a transfer device 74 such as a transfer robot for transferring the substrate W to and from the processing area 702 is arranged. Further, a drawing control unit 75 that is electrically connected to each unit of the drawing device 7 and controls the operation of each unit is disposed in the main body of the drawing device 7.

  The stage 71 has a flat outer shape, and holds the substrate W in a horizontal posture on the upper surface thereof. A plurality of suction holes (not shown) are formed on the upper surface of the stage 71, and by applying a negative pressure (suction pressure) to the suction holes, the substrate W placed on the stage 71 is placed on the stage 71. It can be fixed to the upper surface of. Then, the stage 71 is moved in the sub-scanning direction (left and right direction in FIG. 11) by the stage moving mechanism 72.

  The optical head 73 scans the laser beam based on the strip data corresponding to the drawing pattern. Specifically, the optical head 73 includes a laser light source 731 (light source unit), an optical deflector 732 that scans the laser light emitted from the laser light source 731 in the main scanning direction (the direction perpendicular to the plane of FIG. 11), and an optical head. And a scanning optical system 733 that forms an image of the laser beam scanned by the deflector 732 on the substrate W on the stage 71. Here, the optical deflector 732 has the same configuration as the optical deflector 1 according to any of the above-described embodiments.

  Then, the drawing control unit 75 (control unit) moves the substrate W on the stage 71 in the sub-scanning direction by the stage moving mechanism 72, and the laser beam from the laser light source 731 modulated based on the strip data is an optical deflector 732. To scan in the main scanning direction. Thus, the upper layer pattern (drawing pattern) is overlaid and exposed on the lower layer pattern formed on the unprocessed substrate W. In other words, the drawing apparatus 7 adjusts the position where the laser light that has passed through the optical deflector 732 is irradiated on the substrate W by controlling the deflection of the laser light by the optical deflector 732, and thereby creates a drawing pattern on the substrate W. draw.

  FIG. 12 is a diagram schematically illustrating a schematic configuration of an embodiment of an illumination device including the optical deflector according to the present invention. The illumination device 8 emits four light sources 81r, 81g, 81b, 81y (light source units) that emit light L of different colors (red, green, blue, yellow) and light sources 81r, 81g, 81b, 81y. And an illumination optical system 83 for irradiating the irradiation target with the light L deflected by the light deflector 82.

  The optical deflector 82 includes four multistage deflecting elements 2r, 2g, 2b, and 2y corresponding to the four light sources 81r, 81g, 81b, and 81y, respectively. These multistage deflection elements 2r, 2g, 2b, 2y have the same configuration as any of the multistage deflection elements 2 described above. Similarly to the above, the electrode section 3 is provided for each of the four multistage deflection elements 2r, 2g, 2b, 2y. Accordingly, the light L emitted from the light sources 81r, 81g, 81b, and 81y is deflected by the corresponding multistage deflection elements 2r, 2g, 2b, and 2y, and irradiated to the position SP by the illumination optical system 83.

  Furthermore, the illumination device 8 includes an operation unit 84 that receives a user operation, and an illumination control unit 85 that controls the light deflector 82 in accordance with an operation on the operation unit 84. The illumination control unit 85 determines the irradiation direction of the position SP based on the content of the input to the operation unit 84 and outputs this to the drive control unit 5 of the optical deflector 82. And the drive control part 5 controls the drive part 41 based on the irradiation direction received from the illumination control part 85, and deflects the light by the multistage deflection | deviation elements 2r, 2g, 2b, 2y in the direction according to the said irradiation direction. Adjust the direction.

  In this example, the light L is deflected by the multistage deflecting elements 2r, 2g, 2b, and 2y. However, as shown in the second embodiment, the multistage deflecting element 2 and the continuous deflecting unit 6 continuously Alternatively, the light L may be deflected. In this example, four multistage deflection elements 2r, 2g, 2b, and 2y are arranged in a planar shape. However, the four multistage deflecting elements 2r, 2g, 2b, and 2y and the electrode portions 3 provided corresponding to these may be stacked on each other.

  FIG. 13 is a diagram schematically showing an embodiment of an obstacle detection apparatus including an optical deflector according to the present invention. The obstacle detection device 9 is a so-called LIDAR (Laser Imaging Detection and Ranging) device that detects the obstacle B. The obstacle detection device 9 includes a light source 91 (light source unit), a beam splitter 92, an optical deflector 93 that deflects the light L emitted from the light source 91 and passed through the beam splitter 92, and is deflected by the optical deflector 93. An imaging optical system 94 that forms an image of the generated light L.

  The optical deflector 93 includes the multistage deflection element 2. The multistage deflection element 2 has the same configuration as any of the multistage deflection elements 2 described above. Similarly to the above, the electrode unit 3 is provided for the multistage deflection element 2. Therefore, the drive control unit 5 can scan the light L emitted from the light source 91 in the Y direction by the multistage deflection element 2 by controlling the voltage corresponding to the signal applied from the drive unit 41 to the electrode unit 3. it can. In this example, the light L is scanned by the multistage deflecting element 2, but as shown in the second embodiment, the light L is continuously scanned by the multistage deflecting element 2 and the continuous deflecting unit 6. May be.

  The obstacle detection device 9 detects the obstacle B by confirming that the light L thus scanned is reflected by the obstacle B. That is, the obstacle detection device 9 includes an optical sensor 95 (detection unit) and a rider control unit 96 (control unit). A part of the light L reflected by the obstacle B passes through the imaging optical system 94 and the multistage deflection element 2 and is reflected by the beam splitter 92 to the optical sensor 95. And the rider control part 96 judges the presence or absence of the obstruction B by confirming that the optical sensor 95 received light.

Thus, in the above-described embodiment, the optical deflector 1 corresponds to an example of the “optical deflector” of the present invention, the multistage deflecting element 2 corresponds to an example of the “multistage deflecting element” of the present invention, and the domain-inverted region. Sa ₁ , Sa ₂ , Sa ₃ correspond to an example of the “one deflection region” of the present invention, the electrode unit 3 corresponds to an example of the “electrode unit” of the present invention, and the signal electrodes Ea ₁ , Ea ₂ , Ea ₃ corresponds to an example of the “one deflection electrode” of the present invention, and the domain-inverted regions Sb ₁ , Sb ₂ , Sb ₃ correspond to an example of the “other deflection region” of the present invention, and the signal electrodes Eb ₁ , Eb ₂ and Eb ₃ correspond to an example of the “other deflection electrode” of the present invention, the drive control unit 5 corresponds to an example of the “scanning control unit” of the present invention, and the continuous deflection unit 6 corresponds to the “continuous deflection” of the present invention. The prisms 66 and 67 correspond to an example of the “prism” of the present invention, and the common signal 691 corresponds to an example of the “common electrode” of the present invention, the polygon mirror PM corresponds to an example of the “scanning deflection unit” of the present invention, the light L corresponds to an example of “light” of the present invention, and the X direction Corresponds to an example of the “traveling direction” of the present invention, the main scanning direction Y corresponds to an example of the “first scanning direction” of the present invention, and the rotation direction C corresponds to an example of the “second scanning direction” of the present invention. Equivalent to.

  The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention. For example, the number of polarization inversion regions Sa constituting the multistage deflection element 2 may be two or more and can be changed as appropriate. Specifically, the number of polarization inversion regions Sa may be changed according to the performance required for the optical deflector 1. Therefore, when a wide deflection angle is required, the multistage deflection element 2 may be configured by 10 or more polarization inversion regions Sa.

  Similarly, the number of polarization inversion regions Sb can be changed as appropriate. At this time, the number of polarization inversion regions Sb may be different from the number of polarization inversion regions Sa.

  In the multistage deflection element 2, adjacent polarization inversion regions Sa are not necessarily in contact with each other, and a gap may be provided between them. The same applies to the domain-inverted region Sb.

In addition, the specific values of the period Λa and the inclination angle φa in the domain-inverted region Sa may be set as appropriate according to the specifications required for the optical deflector 1. At this time, in the periodic polarization inversion structure of the polarization inversion region Sa _{I in} which the light L is incident on the I (I is an integer of 1 or more) out of the Na polarization inversion regions Sa, the polarization sections 26 and 27 have the period Λa _i. interface plane 28 of the polarization regions 26 and 27 adjacent to each other with periodically arranged in the angularly .phi.a _i inclined with respect to a given traveling direction, the following relationship _{φa i = θ i-1 +} arcsin (λ / 2nΛa i)
n: Refractive index of the crystal constituting the periodically poled structure θ _i-1 : Angle between the light L incident on the I-th domain-inverted region Sa _I and the traveling direction X λ: The wavelength of the light L is satisfied In addition, the optical deflector 1 may be configured. As a result, the light L incident on the domain-inverted region Sa can be reliably deflected by Bragg diffraction. The same applies to the polarization inversion region Sb.

In the above embodiment, the domain-inverted regions Sa ₁ , Sa ₂ , and Sa ₃ are formed in the same electro-optic crystal substrate. However, the polarization inversion regions Sa ₁ , Sa ₂ , Sa ₃ may be formed in different electro-optic crystal substrates. The same applies to the domain-inverted regions Sb ₁ , Sb ₂ , Sb ₃ .

  Further, the configuration of the continuous deflection unit 6 shown in the second and third embodiments can be modified. FIG. 14 is a diagram schematically showing a modification of the optical deflector shown in the second embodiment, and FIG. 15 is a diagram schematically showing a modification of the deflector shown in the third embodiment. In the continuous deflection unit 6 shown in FIGS. 14 and 15, prisms 66 and 67 whose polarization directions are reversed are alternately arranged in the X direction to form a prism group 667, and a plurality of prism groups 667 are arranged in the Y direction. It is arranged.

When a voltage corresponding to the signal is applied from the driving unit 42 to the common signal electrode 691, a difference in refractive index corresponding to the magnitude of the voltage corresponding to the signal is generated between the prisms 66 and 67. Therefore, the drive unit 42 can continuously change the angle at which the continuous deflection element 61 deflects the light L by changing the magnitude of the voltage corresponding to the signal to the common signal electrode 691. Therefore, the drive control unit 5 continuously scans the light L in the Y direction in a range including the irradiation positions Pa _{0 to} Pa ₃ by controlling the voltage corresponding to the signal applied by the drive unit 41 and the drive unit 42. it can.

  In these modifications, a large number of minute prisms 66 and 67 can be arranged in a matrix in the X direction and the Y direction, so that the refracting surface (prism surface 68) can be formed without increasing the size of the optical deflector 1. Can be increased. Therefore, since the refraction angle of each refracting surface can be reduced, the voltage applied to the prisms 66 and 67 (polarization inversion structure) can be set low, and light deflection can be performed at higher speed.

  In the modification shown in FIG. 15, the prism surfaces 68 of the prisms 66 and 67 have a curved shape that is convex in the light traveling direction, that is, in the X direction. By finishing the prism surface 68 in such a shape, vignetting on the prism surface 68 (the surface through which the light L passes) can be suppressed. In particular, the prism surface 68 has a shape in which the declination of each of the prisms 66 and 67 is the minimum declination. This makes it possible to more reliably suppress vignetting on the prism surface 68. In addition, since the refraction angle of each refracting surface can be reduced, the voltage applied to the prisms 66 and 67 (polarization inversion structure) can be set low, and higher-speed light deflection is possible as described above.

  Next, examples of the present invention will be shown. However, the present invention is not limited by the following examples as a matter of course, and it is of course possible to implement the present invention with appropriate modifications within a range that can meet the gist of the preceding and following descriptions. They are all included in the technical scope of the present invention.

FIG. 16 is a contour map of the light intensity distribution showing an example of a specific simulation result of the present invention. As a result, a state in which the light L traveling in the + X direction is deflected by the optical deflector 1 according to the first embodiment in which the three-stage domain-inverted regions Sa ₁ , Sa ₂ , Sa ₃ are arranged in series is shown as BPM (Beam It was obtained by simulation by Propagation Method). Further, the period Λ = 10 μm of the periodically poled structure, the wavelength λ = 633 nm of the light L, the length L = 2 mm in the X direction of the domain-inverted region Sa, the thickness t = 50 μm of the electro-optic crystal substrate, The simulation was performed under numerical conditions of refractive index n _e = 2.1936 and drive voltage 30V.

In FIG. 16, the deflection angle of the light L is shown with the horizontal axis as the Y direction and the vertical axis as the X direction. The result with the numeral “0” indicates the case where no voltage is applied to all the polarization inversion regions Sa ₁ , Sa ₂ , Sa ₃ of the three stages. The result with the numeral “1” indicates the case where a voltage is applied only to the first-stage polarization inversion region Sa ₁ . The result with the numeral “2” indicates the case where a voltage is applied only to the first and second polarization inversion regions Sa ₁ and Sa ₂ . The result with the numeral “3” indicates the case where a voltage is applied to all three domain-inverted regions Sa ₁ , Sa ₂ , Sa ₃ . In this way, by increasing the number of polarization inversion regions Sa ₁ , Sa ₂ , Sa ₃ for generating diffraction gratings, counted from the beginning of the light L passing sequence, the deflection angle of the light L in the Y direction is increased. I understand that I can do it.

  The present invention can be applied to all techniques for deflecting light.

1 ... Optical deflector,
2 ... Multi-stage deflection element,
3 ... electrode part,
5 ... Drive control unit (scanning control unit),
6 ... Continuous deflection part,
66, 67 ... Prism,
691 ... Common signal electrode (common electrode),
C: Rotation direction (second scanning direction)
Ea ₁ , Ea ₂ , Ea ₃ ... Signal electrode (one deflection electrode),
Eb ₁ , Eb ₂ , Eb ₃ ... Signal electrode (the other deflection electrode),
Sa ₁ , Sa ₂ , Sa ₃ ... Domain inversion region (one deflection region),
Sb ₁ , Sb ₂ , Sb ₃ ... Domain inversion region (the other deflection region),
L ... light,
PM: Polygon mirror (scanning deflection unit),
X ... X direction (traveling direction),
Y: main scanning direction (first scanning direction),
+ Y ... one side,
-Y ... the other side

Claims (17)

An optical deflector for deflecting light traveling in a predetermined traveling direction,
A multistage deflecting element having periodic polarization reversal structures in which areas in which the directions of polarization are reversed are periodically arranged, and having Na (Na is an integer of 2 or more) one deflection region through which the light passes in order; ,
An electrode portion having Na one deflection electrodes provided corresponding to the Na one deflection regions,
Each of the one deflection regions includes a diffraction grating that diffracts the light in a direction inclined to one side with respect to the traveling direction when a voltage is applied to the corresponding one deflection electrode. To generate
The diffraction grating generated in the one deflection region where the light is incident first among the Na one deflection regions deflects the light incident from the traveling direction by Bragg diffraction,
The diffraction grating generated in the one deflection area where the light enters Ma (Ma is an integer not less than 2 and not more than Na) is generated in the one deflection area where the light enters (Ma-1) th. An optical deflector for deflecting the light deflected by Bragg diffraction by the diffraction grating to be deflected by Bragg diffraction. The multistage deflection element further includes Nb (Nb is an integer of 2 or more) other deflection regions each having the periodic polarization inversion structure,
The electrode portion further includes Nb other deflection electrodes provided corresponding to the Nb other deflection regions,
Each of the other deflection regions includes a diffraction grating that diffracts the light in a direction inclined to the other side with respect to the traveling direction when a voltage is applied to the corresponding other deflection electrode. To generate
The diffraction grating generated in the other deflection region where the light is incident first among the Nb other deflection regions deflects the light incident from the traveling direction by Bragg diffraction,
The diffraction grating generated in the other deflection region where the light is incident on Mb (Mb is an integer not smaller than 2 and Nb) is generated in the other deflection region where the light is incident on the (Mb-1) th. The optical deflector according to claim 1, wherein the diffraction grating deflects the light deflected by Bragg diffraction by Bragg diffraction.   3. The optical deflector according to claim 2, wherein the number Na of the one deflection region is equal to the number Nb of the other deflection region.   4. The optical deflector according to claim 3, wherein the Nb other deflection regions are arranged after the Na one deflection regions in the order in which the light passes.   The optical deflector according to claim 3, wherein the one deflection region and the other deflection region are alternately arranged in the order in which the light passes.   The scanning control unit according to claim 1, further comprising a scanning control unit that controls the voltage applied to the electrode unit to scan the light with the multistage deflection element in a first scanning direction that intersects the traveling direction. The optical deflector according to one item. A continuous deflecting unit that continuously deflects the light that has passed through the multistage deflecting element in the first scanning direction;
The scanning control unit adjusts a deflection angle of the light by the continuous deflecting unit, and irradiates the light between a plurality of discrete positions where the light can be irradiated by the multistage deflecting element. The optical deflector according to claim 6, wherein light is continuously scanned in the first direction. The continuous deflection unit includes a plurality of prisms through which the light sequentially passes and a common electrode provided in common to the plurality of prisms, and the polarization direction of the plurality of prisms in the order in which the light passes through Inverted alternately
8. The scanning control unit according to claim 7, wherein the scanning control unit deflects the light that has passed through the multistage deflection element continuously in the first scanning direction by the continuous deflection unit by controlling a voltage applied to the common electrode. The optical deflector as described.   The light deflector according to claim 8, wherein the light passage surface of the prism has a shape curved convexly in the traveling direction.   The optical deflector according to claim 9, wherein the passage surface has a shape in which a deflection angle of each prism is a minimum deflection angle.   The said continuous deflection | deviation part WHEREIN: The prism group comprised by these prisms by which the direction of polarization alternates in the order which the said light passes alternately is arranged in the direction orthogonal to the said advancing direction. The optical deflector according to claim 10.   The optical deflector according to claim 7, further comprising a scanning deflecting unit that deflects the light that has passed through the multistage deflecting element in a second scanning direction orthogonal to the first scanning direction. In the periodic polarization reversal structure of the one deflection region in which the light enters I (I is an integer of 1 or more) of the Na one deflection regions, the section is periodically arranged with a period Λ _i. The boundaries of the areas that are arranged and adjacent to each other are inclined by an angle φ _{i with} respect to the traveling direction, and the following relational expression φ _i = θ _i−1 + arcsin (λ / 2nΛ _i )
n: refractive index of the crystal constituting the periodically poled structure θ _i-1 : angle between the light incident on the I-th one deflection region and the traveling direction λ: the wavelength of the light is satisfied The optical deflector according to any one of 1 to 12. A light source unit;
The optical deflector according to any one of claims 1 to 13, which deflects light from the light source unit,
A control unit that adjusts a position at which the light passing through the optical deflector is irradiated onto the drawing target by controlling the deflection of the light by the optical deflector and draws a pattern on the drawing target; Drawing device. A light source unit;
The optical deflector according to any one of claims 1 to 13, which deflects light from the light source unit,
An illuminating device comprising: a control unit configured to irradiate the irradiation target with the light by controlling the deflection of the light by the optical deflector. A light source unit;
The light deflector according to any one of claims 1 to 13, which scans light from the light source unit,
A detection unit for detecting reflection of the scanned light by an obstacle;
An obstacle detection apparatus comprising: a control unit that determines presence or absence of the obstacle based on a detection result of the detection unit. An optical deflection method for deflecting light incident from a traveling direction,
Each of the one-polarization regions (Na is an integer of 2 or more) through which the light sequentially passes has a periodic polarization reversal structure in which areas where the directions of polarization are reversed are periodically arranged. Injecting the light from a direction;
A step of controlling a voltage applied to the Na one deflection electrode provided corresponding to the Na one deflection region,
Each of the one deflection regions includes a diffraction grating that diffracts the light in a direction inclined to one side with respect to the traveling direction when a voltage is applied to the corresponding one deflection electrode. To generate
The diffraction grating generated in the one deflection region where the light is incident first among the Na one deflection regions deflects the light incident from the traveling direction by Bragg diffraction,
The diffraction grating generated in the one deflection area where the light enters Ma (Ma is an integer not less than 2 and not more than Na) is generated in the one deflection area where the light enters (Ma-1) th. An optical deflection method for deflecting the light deflected by Bragg diffraction by a diffraction grating to be deflected by Bragg diffraction.