Optical device

Abstract

To provide an optical device capable of relatively easily changing spreading degree of a light beam.SOLUTION: The optical device comprises: an optical deflector emitting a light beam a beam spread angle of which is wider in a second direction intersecting a first direction than in the first direction, the optical deflector capable of changing the emission direction of the light beam along the first direction; and an optical element arranged on a path of the light beam and further spreading the beam spread angle of the light beam in the second direction.SELECTED DRAWING: Figure 1A

Description

[Technical field]

[0001] The present disclosure relates to optical devices. [Background technology]

[0002] Conventionally, various devices have been proposed that scan a scene with a light beam, detect reflected light from an object included in the scene, and measure the distance to the object (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-128663 A [Patent Document 2] US Patent Application Publication No. 2018 / 0224709 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides an optical device that allows the degree of divergence of a light beam to be changed relatively easily. [Means for solving the problem]

[0005] An optical device according to one embodiment of the present disclosure includes an optical deflection device that emits a light beam having a shape extending in a first direction from a light exit surface parallel to a first direction and a second direction intersecting the first direction, toward a direction intersecting the light exit surface, the optical deflection device being capable of changing the emission direction of the light beam along the first direction, and an optical element that is arranged on a path of the light beam and changes the degree of spread of the light beam in the second direction. Effect of the Invention

[0006] According to the technique of the present disclosure, it is possible to realize an optical device that can relatively easily change the degree of divergence of a light beam. [Brief description of the drawings]

[0007] [Figure 1A] FIG. 1A is a perspective view illustrating a schematic example of an optical deflection device. [Figure 1B] FIG. 1B is a view of the configuration shown in FIG. 1A taken along the +Y direction. [Diagram 2] FIG. 2 is a perspective view illustrating a schematic example of an optical device according to the first embodiment of the present disclosure. [Figure 3A] FIG. 3A is a view of the configuration shown in FIG. 2 taken along the +Y direction. [Figure 3B] FIG. 3B is a view of the configuration shown in FIG. 2 taken along the +Y direction. [Figure 4] FIG. 4 is a view of the configuration shown in FIG. 2 taken along the +X direction. [Figure 5A] FIG. 5A is a plot of the calculation results of the relationship between the width of the optical deflection device and the divergence angle of the light beam when no optical element is present. [Figure 5B] FIG. 5B is a plot of the calculation results of the relationship between the width of the optical deflection device and the divergence angle of the light beam when an optical element is present. [Figure 6A] FIG. 6A is a perspective view illustrating an example of an optical device according to a first modified example of the first embodiment. FIG. [Figure 6B] FIG. 6B is a view of the configuration shown in FIG. 6A taken along the +X direction. [Figure 7A] FIG. 7A is a perspective view illustrating a schematic example of an optical device according to a second modification of the first embodiment. FIG. [Figure 7B] FIG. 7B is a view of the configuration shown in FIG. 7A taken along the +X direction. [Figure 8A] FIG. 8A is a perspective view illustrating an example of an optical device according to a third modified example of the first embodiment. [Figure 8B] FIG. 8B is a view of the configuration shown in FIG. 8A taken along the +X direction. [Figure 8C] FIG. 8C is a diagram showing a schematic diagram of intensity distribution in the far field of a light beam emitted from a lens array and a single lens. [Figure 9] FIG. 9 is a perspective view illustrating a schematic example of an optical device according to a fourth modified example of the first embodiment. [Figure 10A] FIG. 10A is a perspective view illustrating an example of an optical device according to a fifth modified example of the first embodiment. FIG. [Figure 10B] FIG. 10B is a view of the configuration shown in FIG. 10A taken along the +Y direction. [Figure 10C] FIG. 10C is a perspective view illustrating an example of an optical device according to a sixth modified example of the first embodiment. [Figure 10D] FIG. 10D is a view of the configuration shown in FIG. 10C taken along the +Y direction. [Figure 10E] FIG. 10E is a perspective view illustrating an example of an optical device according to a seventh modification of the first embodiment. [Figure 10F] FIG. 10F is a view of the configuration shown in FIG. 10E taken along the +Y direction. [Figure 11] FIG. 11 is a perspective view illustrating a schematic example of an optical device according to the second embodiment of the present disclosure. [Figure 12A] FIG. 12A is a view of the configuration shown in FIG. 11 as viewed along the +Y direction. [Figure 12B] FIG. 12B is a view of the configuration shown in FIG. 11 as viewed along the +Y direction. [Figure 13] FIG. 13 is a view of the configuration shown in FIG. 11 viewed along the +X direction. [Figure 14] FIG. 14 is a perspective view diagrammatically illustrating an example of an optical device 300 according to the third embodiment of the present disclosure. [Figure 15A] FIG. 15A is a view of the configuration shown in FIG. 14 as viewed along the +Y direction. [Figure 15B] FIG. 15B is a view of the configuration shown in FIG. 14 taken along the +X direction. [Figure 16A] FIG. 16A is a perspective view diagrammatically illustrating an example of an optical device 310 according to a modification of the third embodiment. [Figure 16B] FIG. 16B is a view of the configuration shown in FIG. 16A viewed along the +Y direction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Before describing the embodiments of the present disclosure, the findings on which the present disclosure is based will be described.

[0009] FIG. 1A is a perspective view showing an example of a structure of an optical deflection device 10 according to an exemplary embodiment. FIG. 1B is a view showing the structure shown in FIG. 1A along the +Y direction. For reference, mutually orthogonal X-axis, Y-axis, and Z-axis are shown diagrammatically. In this specification, the direction of the axis arrow is the + direction, and the opposite direction is the - direction. The +Z direction is the upward direction, and the -Z direction is the downward direction. However, these names are used merely for convenience of explanation, and do not limit the posture of the optical deflection device 10 when actually used. Furthermore, the shape and size of the whole or part of the structure shown in the drawing do not limit the actual shape and size.

[0010] The optical deflection device 10 emits a light beam emitted from a light source (not shown) in a predetermined direction. The optical deflection device 10 includes a first mirror 10m. 1、 The mirror 10 includes a second mirror 10m2 and an optical waveguide layer 10w. The first mirror 10m1 and the second mirror 10m2 face each other and extend in the X direction. The transmittance of the first mirror 10m1 is higher than that of the second mirror 10m2. At least one of the first mirror 10m1 and the second mirror 10m2 may be formed of a multilayer reflective film in which a plurality of high refractive index layers and a plurality of low refractive index layers are alternately stacked, for example. The first mirror 10m1 and the second mirror 10m2 may be formed of a multilayer reflective film including the same high refractive index layers and the same low refractive index layers. In this case, if the number of layers of the first mirror 10m1 is smaller than the number of layers of the second mirror 10m2, the transmittance of the first mirror 10m1 will be higher than that of the second mirror 10m2. The optical waveguide layer 10w is located between the first mirror 10m1 and the second mirror 10m2.

[0011] The first mirror 10m1 has a light exit surface 10s parallel to the XY plane on the side opposite to the optical waveguide layer 10w. The light 10L propagates in the optical waveguide layer 10w along the X direction while being reflected by the first mirror 10m1 and the second mirror 10m2. At that time, a part of the light 10L is emitted from the light exit surface 10s to the outside as a light beam 10b. The direction of the central axis of the light beam 10b depends on the refractive index and / or thickness of the optical waveguide layer 10w. In this specification, the direction of the central axis of the light beam 10b is simply referred to as the "emission direction of the light beam 10b."

[0012] The optical waveguide layer 10w may have a configuration in which the refractive index and / or thickness change according to the change in the applied driving voltage. In the example shown in FIG. 1B, the optical waveguide layer 10w includes a liquid crystal material, and the optical waveguide layer 10w may be provided with two electrodes 10e for applying a driving voltage. When the driving voltage changes due to the input of a control signal from a control circuit (not shown), the refractive index of the optical waveguide layer 10w changes, and the emission direction of the light beam 10b emitted from the light emission surface 10s changes along the X direction. In another example, the optical waveguide layer 10w may include a gas or liquid, and an actuator that deforms when a driving voltage is applied may be attached to the first mirror 10m1 and / or the second mirror 10m2. When the driving voltage changes due to the input of a control signal from a control circuit (not shown), the thickness of the optical waveguide layer 10w changes with the change in the mirror interval due to the deformation of the actuator, and the emission direction of the light beam 10b emitted from the light emission surface 10s changes along the X direction. As described above, the optical deflection device 10 can change the emission direction of the light beam 10b emitted from the light emitting surface 10s along the X direction in response to an external control signal. The thick line parallel to the X direction in Fig. 1A indicates the scanning direction of the light beam 10b.

[0013] Details of the optical deflection device 10, including its operating principle and method, are disclosed in U.S. Patent Application Publication No. 2018 / 0224709, the disclosure of which is incorporated herein by reference in its entirety.

[0014] Next, the shape of the light beam 10b will be described. The shape of the light beam 10b means the shape of a light spot obtained by irradiating a screen perpendicular to the emission direction of the light beam 10b with the light beam 10b in the far field, assuming that the screen exists. As shown in FIG. 1A, the light beam 10b emitted from the light emission surface 10s extending along the X direction has a shape extending along the Y direction, such as a line shape or an ellipse shape, in the far field. As shown in FIG. 1A, the spread angle of the light beam 10b in the Y direction is larger than the spread angle of the light beam 10b in the X direction.

[0015] When the optical deflection device 10 is used in a LiDAR (Light Detecting And Ranging) system that measures the distance to an object by light, the degree of spread of the light beam 10b in the Y direction is appropriately adjusted according to the application of the LiDAR system. When the LiDAR system is applied to a moving object such as an automobile, the distance to an object at a short distance can be measured with a small number of scans by changing the light beam extending along the horizontal direction of the road along the vertical direction of the road. On the other hand, the distance to an object at a long distance can be measured by relatively reducing the degree of spread of the light beam 10b in the horizontal direction of the road and increasing the irradiation energy per unit area of ​​the light beam 10b.

[0016] The degree of spread in the Y direction of the light beam 10b emitted from the light deflection device 10 is determined by the structure of the light deflection device 10, specifically, the width in the Y direction of the light exit surface 10s. The narrower the width in the Y direction of the light exit surface 10s, the greater the spread in the Y direction of the light beam 10b, and the wider the width in the Y direction of the light exit surface 10s, the smaller the spread in the Y direction of the light beam 10b. However, the spread of the light beam 10b cannot be significantly changed by structural design alone.

[0017] In the optical device according to the embodiment of the present disclosure, by arranging an optical element on the path of the light beam 10b emitted from the optical deflection device 10, the degree of spread of the light beam 10b in the Y direction can be significantly changed.

[0018] The optical device according to the first item is an optical deflection device that emits a light beam having a shape extending in a second direction from a light exit surface that is parallel to a first direction and a second direction intersecting the first direction, toward a direction intersecting the light exit surface, and is equipped with an optical deflection device capable of changing the emission direction of the light beam along the first direction, and an optical element that is arranged on the path of the light beam and increases the degree of spread of the light beam in the second direction.

[0019] In this optical device, the light beam with an increased divergence can scan a wider range with fewer scans.

[0020] The optical device according to the second item is the optical device according to the first item, wherein the optical element includes at least one lens having a curvature in the second direction.

[0021] In this optical device, the degree of divergence of a light beam emitted from an optical element is changed as a result of the light beam passing through a lens.

[0022] An optical device according to a third aspect is the optical device according to the second aspect, wherein the lens is a concave lens.

[0023] In this optical device, the concave lens can increase the degree of spread of the light beam emitted from the optical element.

[0024] An optical device according to a fourth aspect is the optical device according to the second aspect, wherein the lens is a convex lens.

[0025] In this optical device, the convex lens can increase or decrease the degree of spread of the light beam emitted from the optical element.

[0026] An optical device according to a fifth item is the optical device according to any one of the second to fourth items, wherein the optical element has a portion where the curvature of the lens changes along the first direction.

[0027] In this optical device, even if the emission angle of the light beam changes, the change in the spread of the light beam emitted from the optical element can be suppressed.

[0028] An optical device according to a sixth aspect is the optical device according to any one of the first to fifth aspects, wherein the optical element is in contact with the light exit surface of the optical deflection device.

[0029] In this optical device, the overall size can be reduced by bringing the optical element into contact with the light exit surface of the optical deflection device.

[0030] An optical device according to a seventh aspect is the optical device according to any one of the first aspects, wherein the optical element includes at least one mirror having a curvature in the second direction, the mirror reflecting the light beam emitted from the light emission surface of the optical deflection device.

[0031] In this optical device, the light beam emitted from the optical element is reflected by a mirror, and as a result, the degree of spread of the light beam is changed.

[0032] An optical device according to an eighth aspect is the optical device according to the seventh aspect, wherein the mirror is a convex mirror.

[0033] In this optical device, the convex mirror can increase the degree of spread of the light beam emitted from the optical element.

[0034] An optical device according to a ninth aspect is the optical device according to the seventh aspect, wherein the mirror is a concave mirror.

[0035] In this optical device, the concave mirror can increase or decrease the degree of spread of the light beam emitted from the optical element.

[0036] An optical device according to a tenth item is the optical device according to any one of the seventh to ninth items, wherein the optical element has a portion where the curvature of the mirror changes along the first direction.

[0037] In this optical device, even if the emission angle of the light beam changes, the change in the spread of the light beam reflected by the mirror can be suppressed.

[0038] An optical device according to an eleventh item is an optical device according to any one of the first to tenth items, wherein the optical deflection device comprises a first mirror and a second mirror facing each other and extending in the first direction, and an optical waveguide layer located between the first mirror and the second mirror and guiding light in the first direction.

[0039] In this optical device, a portion of the light propagating through the optical waveguide layer is emitted to the outside.

[0040] An optical device according to a twelfth item is an optical device according to any one of the first to tenth items, wherein the optical deflection device comprises a plurality of optical waveguides arranged along the first direction and extending along the second direction, and a plurality of phase shifters respectively connected to the plurality of optical waveguides.

[0041] In this optical device, a portion of the light that passes through the multiple phase shifters and enters each of the multiple optical waveguides is emitted to the outside.

[0042] An optical device according to a thirteenth aspect is the optical device according to the twelfth aspect, wherein a grating is provided in each of the plurality of waveguides. The light beam is output via the grating.

[0043] In this optical device, a light beam formed by overlapping a plurality of diffracted lights passes through a grating and is output.

[0044] The optical device according to the 14th item is an optical deflection device that emits a light beam having a shape extending in a second direction from a light exit surface parallel to a first direction and a second direction intersecting the first direction, toward a direction intersecting the light exit surface, the optical deflection device being capable of changing the exit direction of the light beam along the first direction, and an optical element that is arranged on the path of the light beam and changes the degree of spread of the light beam in the second direction, the optical element having a first surface onto which the light beam is incident and a second surface from which the light beam exits, and the distance between the light exit surface and the first surface or the second surface of the optical element along a direction perpendicular to the light exit surface changes along the first direction.

[0045] This optical device can suppress changes in the shape and intensity distribution of a light beam that occur during beam scanning.

[0046] An optical device according to the fifteenth item is an optical device according to the fourteenth item, wherein the optical element includes at least one lens having a curvature in the second direction and has a portion where the curvature of the lens changes along the first direction.

[0047] In this optical device, even if the curvature of the lens with respect to the light beam is not strictly constant regardless of the emission angle, it is possible to suppress changes in the shape and intensity distribution of the light beam caused by changes in the emission angle.

[0048] The optical device according to the 16th item is the optical device according to the 14th item, wherein the optical element includes at least one lens having a curvature in the second direction and has a portion where the curvature of the lens is constant along the first direction, and the first surface or the second surface in the portion of the optical element is inclined along the first direction with respect to the light exit surface.

[0049] In this optical device, the lens curvature is kept constant along the first direction, and the change in the optical path length that depends on the output angle can be suppressed, thereby suppressing the change in the shape and intensity distribution of the light beam caused by beam scanning.

[0050] In the present disclosure, all or part of a circuit, unit, device, member or part, or all or part of a functional block in a block diagram may be implemented by one or more electronic circuits including, for example, a semiconductor device, a semiconductor integrated circuit (IC), or an LSI (large scale integration). The LSI or IC may be integrated into one chip, or may be configured by combining multiple chips. For example, functional blocks other than memory elements may be integrated into one chip. Here, although it is called an LSI or an IC, the name may change depending on the degree of integration, and it may be called a system LSI, a VLSI (very large scale integration), or an ULSI (ultra large scale integration). A Field Programmable Gate Array (FPGA), which is programmed after the manufacture of the LSI, or a reconfigurable logic device, which can reconfigure the junction relationship inside the LSI or set up the circuit partition inside the LSI, can also be used for the same purpose.

[0051] Furthermore, all or part of the functions or operations of a circuit, unit, device, member, or section can be executed by software processing. In this case, the software is recorded in one or more non-transitory recording media such as ROMs, optical disks, hard disk drives, etc., and when the software is executed by a processor, the functions specified in the software are executed by the processor and peripheral devices. The system or device may include one or more non-transitory recording media on which the software is recorded, a processor, and necessary hardware devices, such as interfaces.

[0052] In this disclosure, "light" refers to electromagnetic waves including not only visible light (wavelength of about 400 nm to about 700 nm), but also ultraviolet light (wavelength of about 10 nm to about 400 nm) and infrared light (wavelength of about 700 nm to about 1 mm).

[0053] Hereinafter, more specific embodiments of the present disclosure will be described. However, more detailed explanations than necessary may be omitted. For example, detailed explanations of already well-known matters and overlapping explanations of substantially identical configurations may be omitted. This is to avoid the following explanation becoming unnecessarily redundant and to facilitate understanding by those skilled in the art. Note that the inventors provide the accompanying drawings and the following explanation so that those skilled in the art can fully understand the present disclosure, and do not intend to limit the subject matter described in the claims by them. In the following description, the same reference numerals are used for identical or similar components.

[0054] (Embodiment 1) First, a basic configuration example of the optical device according to the first embodiment of the present disclosure will be described with reference to Fig. 2. Fig. 2 is a perspective view that shows a schematic example of the optical device 100 according to the first embodiment of the present disclosure. In Fig. 2, for ease of understanding, components are shown in a separated state, but these components may be in contact with each other. The same applies to the following perspective views. The optical device 100 according to the first embodiment includes an optical deflection device 10 and an optical element 20.

[0055] The optical deflection device 10 in the first embodiment is as described with reference to Figs. 1A and 1B. The light source described above may include, for example, a semiconductor laser element. The wavelength of the light beam emitted from the light source may be selected depending on the application. When measuring the distance to the object by infrared rays, the wavelength of the light beam may be, for example, 700 nm or more and 2.5 μm or less. The wavelength of the light beam may be a wavelength in the visible range, that is, about 400 nm or more and about 700 nm or less. The wavelength of the light beam may be 2.5 μm or more.

[0056] The optical element 20 in the first embodiment includes a lens 20a and a medium 20b supporting the lens 20a. The optical element 20 is disposed on the path of the light beam 10b emitted from the light deflection device 10. The lens 20a is a plano-concave lens having an upper surface 20as1 and a lower surface 20as2. In FIG. 2, the curvature of the lens 20a is exaggerated. The lens 20a has a curvature in the Y direction at the upper surface 20as1 and a flat bottom surface at the lower surface 20as2. The curvature is defined by the reciprocal of the radius of curvature. The lens 20a is a cylindrical lens having a structure extending in the X direction. The lens 20a may have a curvature in the Y direction on at least one of the upper surface 20as1 and the lower surface 20as2. The radius of curvature may be, for example, 1 mm or more and 100 mm or less. The medium 20b has the same refractive index as the lens 20a, but may have a different refractive index. The medium 20b is in contact with the light exit surface 10s of the optical deflection device 10. The medium 20b may not be in contact with the light exit surface 10s of the optical deflection device 10 depending on the application. The medium 20b may be air, water, or vacuum. The optical element 20 does not need to include both the lens 20a and the medium 20b, and may include at least one of them. The length of the optical element 20 in the X direction may be, for example, 1 mm or more and 5 mm or less, the width in the Y direction may be, for example, 1 mm or more and 10 mm or less, and the height in the Z direction may be, for example, 1 mm or more and 10 mm or less.

[0057] Next, referring to FIG. 3A and FIG. 3B, the change in the emission direction of the light beam 10b emitted from the light emission surface 10s in the light deflection device 10 will be described. FIG. 3A and FIG. 3B are views of the configuration shown in FIG. 2 viewed along the +Y direction. In the example shown in FIG. 3A and FIG. 3B, the light deflection device 10 and the optical element 20 are arranged so that their surfaces viewed along the +X direction are aligned. By changing the refractive index and / or thickness of the optical waveguide layer 10w, the emission direction of the light beam 10b changes along the X direction. In the example shown in FIG. 3A and FIG. 3B, the emission angle of the light beam 10b changes from φ1 to φ2. The emission angle of the light beam 10b corresponds to the angle between the light beam 10b and a plane parallel to the YZ plane. Both φ1 and φ2 have positive values. As shown in Figures 3A and 3B, a part of the light 10L propagating in the optical waveguide layer 10w is output from the light output surface 10s, so that the intensity of the light 10L decreases along the X direction. The distance at which the intensity of the light 10L becomes 1 / e times is called the propagation length l x In order to efficiently emit all of the light beam 10b that has passed through the optical element 20 to the outside from the upper surface 20as1 of the lens 20a of the optical element 20, the length L x is the propagation length l x Specifically, the length L of the optical element 20 is designed to be longer than x is the propagation length l x , the maximum emission angle φ2 of the light beam 10b, and the height L of the optical element 20 in the Z direction. z The light beam 10b is refracted at the upper surface 20as1 of the lens 20a and emitted to the outside.

[0058] Next, referring to FIG. 4, the degree of spread in the Y direction of the light beam 10b that has passed through the optical element 20 will be described. FIG. 4 is a view of the configuration shown in FIG. 2 as seen along the +X direction. The arrowed light rays represent the propagation of the light beam 10b emitted from the light deflection device 10. The optical element 20 emits the light that has entered the optical element 20 in a direction different from the direction of incidence by the refraction effect. A diffraction effect may be used instead of the refraction effect, or both the refraction effect and the diffraction effect may be used. Note that the light beam 10b is emitted from a light emission surface 10s that has a width in the Y direction microscopically, but is described as being emitted from one point for ease of explanation.

[0059] The structure of the optical element 20 is as follows. The refractive index of the lens 20a and the medium 20b is n. The spread angle of the light beam 10b emitted from the light emission surface 10s and propagating in the medium 20b is expressed by a half angle, θ1. The spread angle of the light beam 10b emitted to the outside from the lens 20a is expressed by a half angle, θ2. The width of the light deflection device 10 is w. The width of the light deflection device 10 is equal to the width of the light emission surface 10s. The half width of the lens 20a in the y direction is r0, and the focal length of the lens 20a when viewed along the emission direction of the beam 10b is f. The distance between the principal point H of the lens 20a and the focusing point F of the light beam propagating in the medium 20b is s1. The distance between the principal point H of the lens 20a and the focusing point F of the light beam emitted to the outside is -s2. Note that the principal point H is the principal point when the emission direction of the light beam 10b in the optical element 20 is taken as the optical axis, and s1 and -s2 are distances within the optical element 20 along the emission direction of the light beam 10b.

[0060] First, the spread angle θ1 of the light beam 10b emitted from the light emitting surface 10s will be described. It is assumed that the intensity distribution in the Y direction of the light beam 10b emitted from the light emitting surface 10s shows a shape close to a rectangle in the near field, and its width is the width w of the light deflection device 10. If the wavelength of the light beam 10b is λ, the light intensity I at a point y away from the center of the light deflection device 10 along the Y direction and z away from the light emitting surface 10s along the Z direction is expressed by the following formula (1).

number

[0061] The distribution of light intensity I in the Y direction has a central peak called the main lobe and multiple smaller peaks on either side of it. If the width of light beam 10b is the width of the main lobe, the half width of this main lobe is expressed by the following equation (2).

number

[0062] The divergence angle θ1 of the light beam 10b is expressed by the following formula (3).

number

[0063] From equations (2) and (3), the divergence angle θ1 is expressed by the following equation (4).

number

[0064] When the divergence angle θ1 is sufficiently small, the divergence angle θ1 is approximately represented by the following equation (5).

number

[0065] From equation (4) or equation (5), it can be seen that when the wavelength λ is constant, the divergence angle θ1 increases as w becomes smaller, and decreases as w becomes larger.

[0066] Next, a description will be given of the divergence angle θ2 of the light beam 10b emitted to the outside from the optical element 20. In the example shown in Fig. 4, the lens 20a is actually gently curved, and the distance between the upper surface 20as1 and the lower surface 20as2 of the lens 20a is relatively short compared to the distance s1. When the light beam 10b with a divergence angle θ1 is incident on the lens 20a with a radius r, the distance s1 is approximately represented by the following equation (6).

number

[0067] Here, the distance s1 and the distance s2 satisfy the following formula (7).

number

[0068] By modifying equation (7), the distance s2 is expressed by the following equation (8).

number

[0069] Therefore, the divergence angle θ2 of the light beam 10b is approximately expressed by the following equation (9).

number

[0070] When lens 20a is a plano-concave lens, focal length f is expressed as a negative value, so the smaller the absolute value of focal length f and the larger r, the larger the spread angle θ2. Here, assuming that lens 20a is a lens having a plano-concave shape at least in the y direction and the radius of curvature of the plano-concave lens is R, focal length f is expressed by the following formula (10).

number

[0071] By substituting equation (10) into equation (9), the divergence angle θ2 is expressed by the following equation (11).

number

[0072] From equation (11), it can be seen that the divergence angle θ2 increases as R decreases and increases as r increases.

[0073] Next, with reference to Figures 5A and 5B, the extent to which the spread angle θ2 of the light beam 10b changes compared to the spread angle θ1 will be described. Figure 5A is a diagram plotting the results of calculations of the relationship between the width w of the light deflection device 10 and the spread angle θ1 of the light beam 10b when the optical element 20 is not present. Figure 5B is a diagram plotting the results of calculations of the relationship between the width w of the light deflection device 10 and the spread angle θ2 of the light beam 10b when the optical element 20 is present. In the example shown in Figures 5A and 5B, the wavelength of the light beam 10b is λ=940 nm, and the width w of the light deflection device 10 is 1 μm or more and 10 μm or less.

[0074] The reason for designing the width w of the optical deflection device 10 within this range is as follows. If the optical deflection device 10 is manufactured with high processing accuracy to make the width w of the optical deflection device 10 narrower than 1 μm, the manufacturing cost will be high. In addition, the narrower the width w of the optical deflection device 10, the greater the leakage of the light 10L propagating in the optical waveguide layer 10w to the outside in the Y direction. The large leakage to the outside reduces the propagation efficiency of the light 10L in the optical waveguide layer 10w, and the efficiency of the light beam 10b emitted from the light exit surface 10s decreases. In addition, since the large leakage to the outside also contributes to the light beam 10b, the width of the light exit surface 10s in the Y direction is substantially widened, and the spread angle θ1 of the light beam 10b cannot be increased as expected. On the other hand, if the width w of the optical deflection device 10 is made wider than 10 μm, the size of the chip including the optical deflection device 10 will increase, and the manufacturing cost will increase.

[0075] 5A, the relationship between the width w of the optical deflection device 10 and the divergence angle θ1 of the light beam 10b is calculated by taking into consideration the leakage of light from the optical waveguide layer 10 to the outside in addition to formula (4). When the width w of the optical deflection device 10 is designed to be in the range of 1 μm or more and 10 μm or less, the divergence angle θ1 of the light beam 10b is 6° or more and 34° or less.

[0076] In the example shown in Fig. 5B, the relationship between the width w of the optical deflection device 10 and the divergence angle θ2 of the light beam 10b was calculated by taking into consideration the seepage of light from the optical waveguide layer 10 to the outside in addition to formulas (4), (6), and (11). The refractive index of the optical element 20 was set to n = 1.451, the radius of curvature of the plano-concave lens was set to R = 2.5 mm, and the distance from the focusing point F of the light beam propagating in the medium 20b to s1 = 2 mm, 4 mm, or 6 mm. The dashed line portion shown in Fig. 5B represents the divergence angle θ2 that cannot be realized because the radius r of the light beam 10b exceeds the radius of curvature R of the lens 20a.

[0077] In the example shown in Fig. 5B, when s1 = 2 mm, if the width w of the optical deflection device 10 is designed to be in the range of 1 μm to 10 μm, the spread angle θ2 of the light beam 10b is in the range of 8° to 42°. In the example shown in Fig. 5A, in the same range of width w, the spread angle θ1 of the light beam 10b is in the range of 6° to 34°.

[0078] Similarly, in the example shown in Fig. 5B, when s1 = 4 mm, if the width w of the optical deflection device 10 is designed to be in the range of 2 μm to 10 μm, the spread angle θ2 of the light beam 10b is in the range of 10° to 36°. In the example shown in Fig. 5A, in the same range of width w, the spread angle θ1 of the light beam 10b is in the range of 6° to 23°.

[0079] Similarly, in the example shown in Fig. 5B, when s1 = 6 mm, if the width w of the optical deflection device 10 is designed to be in the range of 3 μm to 10 μm, the spread angle θ2 of the light beam 10b is in the range of 12° to 33°. In the example shown in Fig. 5A, in the same range of width w, the spread angle θ1 of the light beam 10b is in the range of 6° to 17°.

[0080] In any of the cases where s1=2 mm, 4 mm, and 6 mm, the spread angle θ2 of the light beam 10b when the optical element 20 is present is enlarged compared to the spread angle θ1 of the light beam 10b when the optical element 20 is not present. In this way, by providing the optical element 20 on the light deflection device 10, the spread angle θ2 of the light beam 10b can be enlarged without narrowing the width w of the light deflection device 10 with high processing accuracy. This light beam 10b can scan a wider area with fewer scans. In the optical device 100 in the first embodiment, the light beam 10b having a spread degree according to the application can be easily obtained.

[0081] (Modification of the first embodiment) Next, first to fifth modified examples of the optical device 100 in the first embodiment will be described with reference to Fig. 6A to Fig. 10B. The optical element 20 in the optical device 100 may include a lens other than the plano-concave lens 20a extending in the X direction shown in Fig. 2.

[0082] FIG. 6A is a perspective view showing a schematic example of an optical device 110 according to a first modification of the first embodiment. FIG. 6B is a view showing the configuration shown in FIG. 6A viewed along the +X direction. The optical device 110 according to the first modification is different from the optical device 100 according to the first embodiment in that the lens 20a included in the optical element 20 is a plano-convex lens. In the example shown in FIG. 6A and FIG. 6B, the curvature of the plano-convex lens 20a in the Y direction is relatively small. In this case, unlike the above-mentioned example, the spread angle θ2 of the light beam 10b is small. Since the irradiation energy per unit area of ​​the light beam 10b is high, an object at a long distance can be scanned by the light beam 10b.

[0083] Fig. 7A is a perspective view showing a schematic example of an optical device 120 according to a second modification of the first embodiment. Fig. 7B is a view showing the configuration shown in Fig. 7A viewed along the +X direction. The optical device 120 according to the second modification is different from the optical device 110 according to the first modification in that the curvature of the convex lens 20a in the Y direction is relatively large. After being emitted from the convex lens 20a, the light beam 10b is once focused and then diffused. In this case, the spread angle θ2 of the light beam 10b is large.

[0084] As shown in FIGS. 6B and 7B, the spread angle θ2 of the light beam 10b can be increased or decreased depending on the curvature of the convex lens 20a.

[0085] FIG. 8A is a perspective view showing a schematic example of an optical device 130 in a third modified example of the first embodiment. FIG. 8B is a view showing the configuration shown in FIG. 8A viewed along the +X direction. The optical device 130 in the third modified example is different from the optical device 100 in the first embodiment in that the lens 20a included in the optical element 20 is a lens array including a plurality of concave lenses regularly arranged along the Y direction. The plurality of concave lenses may be arranged randomly along the Y direction, or the curvature of each concave lens may vary. The lens array 20a covers the spot range of the light beam 10b incident on the lens array 20a. In the first embodiment, there is a restriction that the beam radius r on the lens 20a cannot exceed the curvature radius R of the lens. In contrast, there is no such restriction in the third modified example. This is because the plurality of concave lenses cover the spot range of the light beam 10b even if the curvature radius R of each concave lens is smaller than the beam radius r of the light beam 10b. As a result, the divergence angle θ2 of the light beam 10b in the dashed line portion shown in FIG. 5B can be realized, and the divergence angle θ2 can be further increased.

[0086] FIG. 8C is a schematic diagram showing the intensity distribution in the far field of the light beam 10b emitted from the lens array and the single lens. The solid line and the dashed line respectively represent the intensity distribution of the light beam 10b emitted from the lens array and the single lens. In the case of the single lens, the intensity of the light beam 10b is almost zero at both ends of the main lobe. In contrast, in the case of the lens array, the intensity of the light beam 10b is higher at both ends, and the maximum intensity at the center of the light beam 10b is lower. In the lens array, the individual concave lenses diffuse the incident light as shown in FIG. 8B, so that the non-uniformity of the intensity distribution can be mitigated as shown in FIG. 8C. Therefore, a wider area in the Y direction can be irradiated with the light beam 10b with a lower intensity.

[0087] FIG. 9 is a perspective view showing a schematic example of an optical device 140 in a fourth modification of the first embodiment. The optical device 140 in the fourth modification is different from the optical device 130 in the third modification in that the lens 20a included in the optical element 20 is a lens array including a plurality of concave lenses regularly arranged along the X direction and the Y direction. The plurality of concave lenses may be arranged randomly along the X direction and the Y direction, or the curvature of each concave lens may vary. The light beam 10b emitted from the light emission surface 10s is diffused in both the X direction and the Y direction. For the reasons described with reference to FIG. 8C, a wider area in the X direction and the Y direction can be irradiated with the light beam 10b with a low intensity.

[0088] The intensity of laser light is classified into classes according to JIS (Japanese Industrial Standards) C6802 "Safety Standards for Laser Products." From the viewpoint of eye safety, it is desirable that the intensity of laser light is Class 1. Even if the intensity distribution of the light beam 10b emitted from the light emission surface 10s does not satisfy Class 1, the intensity distribution of the light beam 10b emitted from the optical element 20 can be made to satisfy Class 1 by diffusing the light beam 10b using the optical element 20 shown in FIG. 8A and FIG. 9.

[0089] FIG. 10A is a perspective view showing a schematic example of an optical device 150 according to a fifth modification of the first embodiment. FIG. 10B is a view showing the configuration shown in FIG. 10A viewed along the +Y direction. The dashed lines shown in FIGS. 10A and 10B are lines connecting stationary points of the concave lens 20a in the Y direction. The optical device 130 according to the fifth modification is different from the optical device 100 according to the first embodiment in that the curvature in the Y direction of the lens 20a included in the optical element 20 changes monotonically along the X direction. Thus, the optical element 20 has a portion in which the curvature in the Y direction of the lens 20a changes along the X direction. As shown in FIG. 10B, when the emission angle of the light beam 10b increases from φ1 to φ2, the passing distance of the light beam 10b in the lens 20a increases. The curvature of the lens 20a for the light beam 10b at a certain emission angle can be known from the cut surface of the lens 20a when the lens 20a is cut along the following plane. The plane is parallel to both the emission direction of the light beam 10b and the Y direction in the optical element 20. If the curvature of the lens 20a in the Y direction is constant along the X direction, the curvature of the lens 20a with respect to the light beam 10b increases with the emission angle of the light beam 10b. In contrast, in the example shown in FIG. 10B, the curvature of the lens 20a in the Y direction is monotonically decreased along the +X direction, so that the curvature of the lens 20a with respect to the light beam 10b can be made constant regardless of the emission angle. In the optical device 150 in the fifth modification, the spread angle θ2 of the light beam 10b is constant regardless of the emission angle of the light beam 10b. The shape and intensity distribution of the light beam 10b do not depend on the emission angle of the light beam 10b. Even if the curvature of the lens 20a with respect to the light beam 10b is not strictly constant regardless of the emission angle, the change in the shape and intensity distribution of the light beam 10b due to the change in the emission angle can be suppressed.

[0090] In the fifth modified example, the upper surface 20as1 of the optical element 20 is a lens surface, and the curvature of the upper surface 20as1 is changed along the X direction, but the lower surface 20as2 of the optical element 20 may be a lens surface, and the curvature of the lower surface 20as2 may be changed along the X direction. In this case, the upper surface 20as1 may be flat.

[0091] FIG. 10C is a perspective view showing a schematic example of an optical device 160 in a sixth modified example of the first embodiment. FIG. 10D is a view showing the configuration shown in FIG. 10C viewed along the +Y direction. As in the above-mentioned embodiment, the medium 20b may not be in contact with the light exit surface 10s of the optical deflection device 10. The optical element 20 of the optical device 160 in the sixth modified example has a portion in which the curvature of the lens 20a in the Y direction is constant along the X direction. The optical device 160 in the sixth modified example is different from the optical device 100 in the first embodiment in that the upper surface 20as1, which is the light exit side surface of the optical element 20 in the lens 20a and is a lens surface, is inclined along the X direction with respect to the light exit surface 10s of the deflection device 10. That is, the distance between the light exit surface 10s and the lens surface 20as1 along the direction perpendicular to the light exit surface 10s is changed along the X direction. In FIG. 10D, the angle between the lens surface 20as1 and the light exit surface 10s when viewed in the X direction is denoted as δ.

[0092] When the curvature of the lens 20a is constant along the X direction, the focal length of the lens 20a is constant along the X direction. On the other hand, macroscopically, the light 10b from the optical deflection element 10 can be considered to be emitted from a sufficiently small point. When the emission angle of the light beam 10b is changed between φ1 and φ2, the shape and intensity distribution of the light beam 10b change depending on the emission angle. This is because the optical path length from the emission point of the light beam 10b to the lens surface 20as1 varies even though the focal length of the lens 20a is constant. In the optical device 160 in the sixth modified example, this variation in the optical path length can be suppressed. Here, it is most preferable that the angle δ is equal to the middle of the emission angle range of the light beam 10b (i.e., (φ1+φ2) / 2).

[0093] A calculation example for explaining the effect of the sixth modified example is shown below. In the following calculation example, φ1=5°, φ2=35°. In addition, the optical path length from the emission point of the optical deflection element 10 to the lens surface at the intermediate emission angle of 20° is 10 mm. When δ=0°, the optical path length from the emission point to the lens surface in the direction perpendicular to the surface 10 of the optical deflection element (i.e., the direction corresponding to the emission angle of 0°) is 10×cos20°=9.40 mm. The optical path length at an emission angle of 5° is (10×cos20°) / cos5°=9.43 mm, and the optical path length at an emission angle of 35° is (10×cos20°) / cos35°=11.47 mm. Therefore, the variation width of the optical path length when the emission angle changes from 5° to 35° is 2.04 mm.

[0094] On the other hand, in the configuration shown in Figures 10C and 10D, when δ = (5° + 35°) / 2 = 20°, the optical path length at an output angle of 5° is 10 x cos (20° - 5°) = 10.35 mm, and the optical path length at an output angle of 35° is 10 x cos (20° - 35°) = 10.35 mm. Therefore, the fluctuation range of the optical path length is 0.35 mm. In other words, it can be seen that the fluctuation range can be suppressed to 17% compared to the case of δ = 0°.

[0095] In this way, in the optical device 160 of the sixth modification, the curvature of the lens 20a is kept constant along the X direction, and the change in the optical path length that depends on the emission angle can be suppressed. As a result, the change in the shape and intensity distribution of the light beam 10b caused by the beam scanning can be suppressed.

[0096] In the sixth modified example, the lower surface 20as2 of the optical element 20 is inclined along the X direction, but may be parallel to the light exit surface 10s of the light deflection device 10. In addition, the light incident surface of the medium 20 is parallel to the light exit surface 10s, but may be inclined along the X direction.

[0097] The lens surface of the lens 20a may be formed on the lower surface 20as2, which is the incident side surface. Figures 10E and 10F are perspective views that typically show an example of an optical device 170 in a seventh modified example of the first embodiment. The optical device 170 in the seventh modified example differs from the optical device 160 in the sixth modified example in that the distance between the light exit surface 10s and the lower surface 20as2 of the optical element 20 along the direction perpendicular to the light exit surface 10s is changed along the X direction.

[0098] In the seventh modification, the upper surface 20as1 of the optical element 20 is parallel to the light exit surface 10s of the optical deflection device 10, but may be tilted along the X direction. Also, the light incident surface of the medium 20 is parallel to the light exit surface 10s, but may be tilted along the X direction.

[0099] (Embodiment 2) Next, a basic configuration example of an optical device according to the second embodiment of the present disclosure will be described with reference to Fig. 11. Fig. 11 is a perspective view that illustrates an example of an optical device 200 according to the second embodiment of the present disclosure. In Fig. 11, for ease of understanding, components of the optical device 200 are illustrated in a separated state, but these components may be in contact with each other. The optical device 200 according to the second embodiment includes an optical deflection device 30 and an optical element 20.

[0100] The optical deflection device 30 in the second embodiment includes a plurality of optical waveguides 30w and a plurality of phase shifters 30p connected to the plurality of optical waveguides 30w, respectively. The plurality of optical waveguides 30w are aligned along the X direction and extend along the Y direction. The number of the plurality of optical waveguides 30w may be, for example, 8 to 64. Each of the plurality of optical waveguides 30w includes a light output region 30r on the surface thereof for outputting light. Each of the plurality of light output regions 30r is provided with a grating 30g. The optical waveguide 30w has a refractive index higher than that of an external medium such as air. The optical waveguide 30w propagates light along the Y direction by total reflection. The light propagating along the Y direction in the optical waveguide 30w is emitted to the outside from the light output region 30r as a plurality of diffracted lights parallel to the YZ plane due to diffraction by the grating 30g. The length of the light emission region 30r in the Y direction may be, for example, 1 μm or more and 10 μm or less. The number of recesses in the grating 30g may be set to, for example, 4 to 16. The length of the recesses in the Y direction per period in the grating 30g, i.e., the duty ratio, may be appropriately changed depending on the depth and number of the recesses in the grating. In the optical deflection device 30 in the second embodiment, a light beam is formed by the interference of light emitted from a plurality of optical waveguides 30w. It can also be said that the light beam is emitted to the outside from a light emission surface 30s including a plurality of light emission regions 30r. The light beam has a shape extending in the Y direction by the overlapping of a plurality of diffracted lights parallel to the YZ plane.

[0101] The multiple phase shifters 30p are arranged along the X direction and extend along the Y direction, similar to the multiple optical waveguides 30w. The phase shifter 30p may have a configuration in which the refractive index changes according to a change in the applied drive voltage. In one example, the phase shifter 30p may be formed from a thermo-optical material whose refractive index changes with a change in temperature. The phase shifter 30p includes a heater (not shown) that changes the temperature of the thermo-optical material. The heater (not shown) is provided with two electrodes for applying a drive voltage. In another example, the phase shifter 30p may be formed from an electro-optical material whose refractive index changes with a change in drive voltage. The phase shifter 30p is provided with two electrodes for applying a drive voltage to the electro-optical material. When the drive voltage changes due to the input of a control signal from a control circuit (not shown), the refractive index of the phase shifter 30p changes, and the phase of the light passing through the phase shifter 30p changes. In the optical deflection device 30 in the second embodiment, the driving voltage changes in response to a control signal, and the phases of the light incident from the phase shifters 30p to the optical waveguides 30w change by a constant amount in the order in which the optical waveguides 30w are arranged. This phase shift allows the emission direction of the light beam to be changed along the X direction.

[0102] Next, referring to Fig. 12A and Fig. 12B, a change in the emission direction of the light beam emitted from the light emission surface 30s in the light deflection device 30 will be described. Fig. 12A and Fig. 12B are views of the configuration shown in Fig. 11 viewed along the +Y direction. In the example shown in Fig. 12A and Fig. 12B, the light deflection device 30 and the optical element 20 are in contact with each other and are arranged symmetrically with respect to a plane parallel to the YZ plane. In the example shown in Fig. 12A and Fig. 12B, the emission angle of the light beam 30b changes from φ1 to φ2. In the light deflection device 30 in the second embodiment, unlike the light deflection device 10 in the first embodiment, φ1 has a negative value and φ2 has a positive value. The absolute values ​​of φ1 and φ2 may be equal or different. In order to efficiently emit all of the light beam 30b that has passed through the optical element 20 to the outside from the upper surface 20as1 of the lens 20a in the optical element 20, the length L in the X direction of the optical element 20 is set to φ1 / φ2 / φ1. x is the length d of the optical deflection device 30 in the X directionx Specifically, the length L of the optical element 20 is designed to be longer than x is the length d of the optical deflection device 30 x , the minimum emission angle φ1 of the light beam 30b, the maximum emission angle φ2 of the light beam 30b, and the height L of the optical element 20 in the Z direction. z The light beam 30b is refracted at the upper surface 20as1 of the lens 20a and emitted to the outside.

[0103] Next, the degree of spread in the Y direction of the light beam 30b that has passed through the optical element 20 will be described with reference to Fig. 13. Fig. 13 is a view of the configuration shown in Fig. 11 viewed along the +X direction. The optical element 20 in the second embodiment has been described with reference to Fig. 4. As shown in Fig. 13, the spread angle θ2 of the light beam 30b is increased by the optical element 20. The optical elements 20 in the first to fifth modifications of the first embodiment may be used as the optical element 20 in the second embodiment.

[0104] In the optical device 200 in the second embodiment, the divergence angle θ2 of the light beam 30b can also be changed by providing the optical element 20 on the optical deflection device 30. Therefore, the light beam 30b having a degree of divergence according to the application can be easily obtained.

[0105] (Embodiment 3) Next, with reference to FIG. 14, a basic configuration example of an optical device according to the third embodiment of the present disclosure will be described. FIG. 14 is a perspective view that illustrates an example of an optical device 300 according to the third embodiment of the present disclosure. The optical device 300 according to the third embodiment is different from the optical device 100 according to the first embodiment in that the optical element 20 includes a mirror 20c instead of the lens 20a. The optical element 20 according to the third embodiment includes a mirror 20c and a medium 20b. The mirror 20c is a plano-convex mirror having an upper surface 20cs1 and a lower surface 20cs2. The mirror 20c has a flat surface on the upper surface 20as1, and has a curvature in the Y direction on the lower surface 20cs2. The lower surface 20cs2 of the mirror 20c corresponds to a reflecting surface. The reflectance of the reflecting surface can be, for example, 90% or more at the wavelength of the light beam 10b. The mirror 20c is a cylindrical mirror having a structure extending in the X direction. The curvature of the plano-convex mirror is equal to the curvature of the plano-concave lens according to the first embodiment. The medium 20b is as described above. In the example shown in Fig. 14, the medium 20b is air. In the example shown in Fig. 14, the direction in which the reflecting surface 20cs2 of the mirror 20c extends is parallel to the direction in which the light exit surface 10s of the optical deflection device 10 extends. In this way, the reflecting surface 20cs2 of the mirror 20c directly faces the light exit surface 10s of the optical deflection device 10.

[0106] 15A and 15B are views of the configuration shown in FIG. 14 as viewed in the +Y and +X directions, respectively. As shown in FIG. 15A, a light beam 10b emitted upward from the light deflection device 10 is reflected downward by the mirror 20c. The shortest distance L between the reflecting surface 20cs2 of the mirror 20c and the light emitting surface 10s of the light deflection device 10 is zis more preferably designed to satisfy the following condition. The condition is that the light beam 10b emitted at the minimum emission angle φ1 and reflected by the reflecting surface 20cs2 of the mirror 20c does not re-enter the light emission surface 10s. This is because such re-entry leads to a loss of the light beam 10b emitted to the outside. As shown in FIG. 15B, the degree of spread of the light beam 10b reflected downward increases. The focusing point F of the light beam reflected by the mirror 20c is located above the lower surface 20cs2 of the mirror 20c. As described above, when the plano-concave lens in the first embodiment is replaced with a plano-convex mirror, although there is a difference in the transmission and reflection of the light beam 10b, the degree of spread of the light beam 10b is expanded in the same manner.

[0107] (Modification of the third embodiment) Next, a modified example of the optical device 300 in the third embodiment will be described with reference to FIG. 16A and FIG. 16B. FIG. 16A is a perspective view showing a schematic example of an optical device 310 in the modified example of the third embodiment. FIG. 16B is a view showing the configuration shown in FIG. 16A viewed along the +Y direction. The optical device 310 in the modified example of the third embodiment is different from the optical device 300 in the third embodiment in that the direction in which the reflecting surface 20cs2 of the mirror 20c extends is not parallel to the direction in which the light emitting surface 10s of the light deflection device 10 extends. In this way, the reflecting surface 20cs2 of the mirror 20c is inclined with respect to the light emitting surface 10s of the light deflection device 10. Therefore, it is possible to significantly reduce the possibility that the light beam 10b reflected downward by the reflecting surface 20cs2 of the mirror 20c re-enters the light emitting surface 10s. Furthermore, as shown in FIG. 16B, the shortest distance L between the reflecting surface 20cs2 of the mirror 20c and the light emitting surface 10s of the light deflection device 10 is 1 / 2.5 mm. z The shortest distance L z If the length of the mirror 20c can be shortened, the light beam 10b emitted from the optical deflection device 10 can be reflected by the mirror 20c before the light beam 10b is largely expanded, as compared with the example shown in Fig. 15B. Therefore, the size of the mirror 20c in the Y direction can be reduced.

[0108] In the optical device of the present disclosure, the light exit surface 10s of the optical deflection device 10 faces the direction in which the reflecting surface 20cs2 of the mirror 20c is located, as shown in Figures 14 and 16A. The light beam 10b emitted from the light exit surface 10s of the optical deflection device 10 is incident on the reflecting surface 20cs2 of the mirror 20c.

[0109] In addition to the above examples, when the plano-convex lenses in the first and second modified examples of the first embodiment are replaced with plano-concave mirrors, the degree of spread of the light beam 10b is expanded or contracted in the same manner, although there is a difference in the transmission and reflection of the light beam 10b. The mirror 20c may include multiple mirrors as shown in Figures 8A and 9. The mirror 20c may have a portion whose curvature in the Y direction changes along the X direction as shown in Figure 10A. [Industrial Applicability]

[0110] The optical device according to the embodiment of the present disclosure can be used, for example, to measure the distance to an object. [Explanation of symbols]

[0111] 10 Light deflection device 10L light 10b Light beam 10e electrode 10m1 1st mirror 10m2 2nd mirror 10s light exit surface 10w optical waveguide layer 20 Optical elements 20a Lens Top of 20as1 lens Underside of 20as2 lens 20b Medium 20c Mirror Top of 20cs1 mirror 20cs2 mirror bottom 30 Light deflection device 30b Light beam 30g Grating 30p Phase Shifter 30r light output area 30s light exit surface 30w optical waveguide 100, 110, 120, 130, 140, 150, 200, 300, 310 Optical Devices

Claims

1. an optical deflection device that emits a light beam having a beam spread angle in a second direction intersecting with a first direction that is larger than the beam spread angle in the first direction, and that is capable of changing an emission direction of the light beam along the first direction; an optical element disposed on a path of the light beam and configured to further increase a beam divergence angle of the light beam in the second direction; Equipped with Optical devices.

2. The optical device of claim 1 , wherein the optical element comprises at least one lens having a curvature in the second direction.

3. The lens is a concave lens.

3. The optical device according to claim 2.

4. The lens is a convex lens.

3. The optical device according to claim 2.

5. The optical element has a portion where the curvature of the lens varies along the first direction.

5. An optical device according to claim 2.

6. The optical element is in contact with a light exit surface of the optical deflection device from which the light beam is emitted.

6. An optical device according to claim 1.

7. the optical element includes at least one mirror having a curvature in the second direction; the mirror reflects the light beam emitted from a light emitting surface of the optical deflection device from which the light beam is emitted; The optical device according to claim 1 .

8. The mirror is a convex mirror.

8. The optical device according to claim 7.

9. The mirror is a concave mirror.

8. The optical device according to claim 7.

10. The optical element has a portion where the curvature of the mirror changes along the first direction.

10. An optical device according to claim 7.

11. The optical deflection device includes: a first mirror and a second mirror facing each other and extending in the first direction; an optical waveguide layer located between the first mirror and the second mirror and guiding light in the first direction; Equipped with 11. An optical device according to claim 1.

12. The optical deflection device includes: a plurality of optical waveguides aligned along the first direction and extending along the second direction; a plurality of phase shifters respectively connected to the plurality of optical waveguides; 11. An optical device according to claim 1.

13. A grating is provided in each of the plurality of optical waveguides, and the light beam is emitted through the grating.

13. The optical device of claim 12.

14. an optical deflection device that emits a light beam having a beam spread angle in a second direction intersecting with a first direction that is larger than the beam spread angle in the first direction, and that is capable of changing an emission direction of the light beam along the first direction; an optical element disposed on a path of the light beam and configured to change a beam divergence angle of the light beam in the second direction; the optical element has a first surface onto which the light beam is incident and a second surface from which the light beam exits, a distance between a light exit surface of the optical deflection device, from which the light beam is exited, and the first surface or the second surface of the optical element along a direction perpendicular to the light exit surface varies along the first direction; Optical devices.

15. the optical element includes at least one lens having a curvature in the second direction and having a portion of the lens where the curvature varies along the first direction; 15. The optical device of claim 14.

16. the optical element includes at least one lens having a curvature in the second direction and a portion of the lens where the curvature is constant along the first direction; The optical device according to claim 14 , wherein the first surface or the second surface in the portion of the optical element is inclined along the first direction with respect to the light exit surface.

17. The optical device of claim 1 or 14, wherein the optical element changes a beam divergence angle of the light beam in the second direction to a greater extent than a beam divergence angle in the first direction.

18. The optical device according to claim 1 or 14, wherein the optical element is a diffusing member that diffuses the light beam.

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