阅读说明：本技术 光设备、光检测系统及其制造方法 (Optical device, optical detection system and manufacturing method thereof ) 是由 野村幸生 佃雅彦 稻田安寿 于 2020-02-07 设计创作，主要内容包括：光设备具备：第1基板,具有第1表面；第2基板,具有与上述第1表面至少局部地对置的第2表面；至少1个光波导,在上述第1基板与上述第2基板之间沿着上述第1方向延伸；以及多个弹性间隔件,配置于上述第1表面及上述第2表面的至少一方,包括第1部分及第2部分。上述多个弹性间隔件的上述第1部分是位于上述第1基板与上述第2基板之间而且从与上述第1表面垂直的方向观察时上述第1基板与上述第2基板重叠的区域中的至少1个弹性间隔件。上述多个弹性间隔件的上述第2部分是位于从与上述第1表面垂直的方向观察时上述第1基板与上述第2基板不重叠的区域中的至少1个弹性间隔件。(The optical device includes: a 1 st substrate having a 1 st surface; a 2 nd substrate having a 2 nd surface at least partially opposed to the 1 st surface; at least 1 optical waveguide extending in the 1 st direction between the 1 st substrate and the 2 nd substrate; and a plurality of elastic spacers, which are disposed on at least one of the 1 st surface and the 2 nd surface, and include a 1 st portion and a 2 nd portion. The 1 st portion of the plurality of elastic spacers is at least 1 elastic spacer located between the 1 st substrate and the 2 nd substrate and in a region where the 1 st substrate and the 2 nd substrate overlap when viewed from a direction perpendicular to the 1 st surface. The 2 nd portion of the plurality of elastic spacers is at least 1 elastic spacer located in a region where the 1 st substrate and the 2 nd substrate do not overlap when viewed from a direction perpendicular to the 1 st surface.)

1. An optical device is provided with:

a 1 st substrate having a 1 st surface extending in a 1 st direction and a 2 nd direction intersecting the 1 st direction;

a 2 nd substrate having a 2 nd surface at least partially opposed to the 1 st surface, the 2 nd surface having an area different from the 1 st surface;

at least 1 optical waveguide extending in the 1 st direction between the 1 st substrate and the 2 nd substrate; and

a plurality of elastic spacers disposed on at least one of the 1 st surface and the 2 nd surface, including a 1 st portion and a 2 nd portion;

the 1 st portion of the plurality of elastic spacers is at least 1 elastic spacer located between the 1 st substrate and the 2 nd substrate and in a region where the 1 st substrate and the 2 nd substrate overlap when viewed from a direction perpendicular to the 1 st surface;

the 2 nd portion of the plurality of elastic spacers is at least 1 elastic spacer located in a region where the 1 st substrate and the 2 nd substrate do not overlap when viewed from a direction perpendicular to the 1 st surface.

2. The optical device of claim 1,

a plurality of partition walls arranged in the 2 nd direction between the 1 st substrate and the 2 nd substrate, each partition wall extending along the 1 st direction;

the elastic spacers have a lower elastic modulus than the partition walls.

3. The optical device of claim 2,

the plurality of partition walls are directly or indirectly clamped by the 1 st substrate and the 2 nd substrate;

the 1 st substrate and the 2 nd substrate are sandwiched, and a deformation ratio of each of the plurality of elastic spacers in a direction perpendicular to the 1 st surface is larger than a deformation ratio of each of the plurality of partition walls in the perpendicular direction.

4. The light device of any one of claims 1-3,

each of the plurality of elastic spacers has a columnar shape.

5. The light device of any one of claims 1 to 4,

the at least 1 optical waveguide includes: a 1 st portion disposed between the 1 st substrate and the 2 nd substrate and in a region where the 1 st substrate and the 2 nd substrate overlap; and a 2 nd portion disposed in a region where the 1 st substrate and the 2 nd substrate do not overlap.

6. The optical device of claim 5,

the at least one optical waveguide is a plurality of optical waveguides;

at least a part of the 2 nd portion of the plurality of elastic spacers is positioned around the 2 nd portion of each of the plurality of optical waveguides.

7. The optical device of claim 5 or 6,

the at least one optical waveguide includes a portion located between two adjacent partition walls, and the portion includes a 1 st grating.

8. The light device of any one of claims 5 to 7,

the at least one optical waveguide includes a 2 nd grating in the 2 nd portion.

9. The light device of any one of claims 1 to 8,

a sealing member for fixing a gap between the 1 st substrate and the 2 nd substrate;

the at least 1 optical waveguide has a structure in which 1 or more 1 st optical waveguides and 1 or more 2 nd optical waveguides are connected to each other;

the sealing member surrounds the 1 st or more optical waveguides 1 when viewed from a direction perpendicular to the 1 st surface.

10. The optical device of claim 9,

the 1 or more 1 st optical waveguides include 1 or more dielectric members each extending in the 1 st direction;

the region between the 1 st substrate and the 2 nd substrate and surrounded by the sealing member is filled with the same members as the 1 or more dielectric members.

11. The light device of any one of claims 1-10,

the 1 or more 1 st optical waveguides include 1 or more dielectric members each extending in the 1 st direction;

the optical device further includes 2 mirrors, and the 2 mirrors are respectively located between the 1 st substrate and the 1 or more dielectric members, and between the 2 nd substrate and the 1 or more dielectric members.

12. The optical device of claim 11,

at least a part of the 1 st portion of the plurality of elastic spacers is located outside a region sandwiched by the 2 mirrors.

13. The light device of any one of claims 10-12,

the 1 st or more optical waveguides have a structure capable of adjusting the refractive index of the 1 or more dielectric members;

by adjusting the refractive index of the 1 or more dielectric members, the direction of light emitted from the 1 or more 1 st optical waveguides through the 1 st substrate or the 2 nd substrate or the direction of incidence of light taken into the 1 or more 1 st optical waveguides through the 1 st substrate or the 2 nd substrate changes.

14. The optical device of claim 13,

a pair of electrodes sandwiching the 1 or more dielectric members;

the 1 or more dielectric members include a liquid crystal material or an electro-optical material;

the refractive index of the 1 or more dielectric members is adjusted by applying a voltage to the pair of electrodes.

15. The optical device of claim 14,

further comprising 1 or more phase shifters directly connected to the 1 st or more optical waveguides or connected to the 1 st or more optical waveguides via another waveguide;

by changing the phase difference of the light passing through the 1 or more phase shifters, the direction of the light emitted from the 1 or more 1 st optical waveguides via the 1 st substrate or the 2 nd substrate or the direction of the light incident on the 1 or more 1 st optical waveguides via the 1 st substrate or the 2 nd substrate is changed.

16. A light detection system is provided with:

the light device of any one of claims 1-15;

a photodetector for detecting light emitted from the optical device and reflected from an object; and

and a signal processing circuit for generating distance distribution data based on the output of the photodetector.

17. A method of manufacturing an optical device, comprising:

preparing a 1 st substrate having a 1 st surface and a 2 nd substrate having a 2 nd surface;

forming at least 1 optical waveguide extending in one direction on the 1 st surface of the 1 st substrate;

forming a plurality of elastic spacers on the 1 st surface of the 1 st substrate or the 2 nd surface of the 2 nd substrate;

a step of fixing the 1 st substrate and the 2 nd substrate by opposing the 1 st surface of the 1 st substrate and the 2 nd surface of the 2 nd substrate so that the plurality of elastic spacers are positioned around the at least 1 optical waveguide; and

and cutting and removing a part of the substrate, which is not provided with the plurality of elastic spacers, out of the 1 st substrate or the 2 nd substrate, to expose a part of the plurality of elastic spacers.

18. The method of manufacturing an optical device according to claim 17,

further comprising a step of forming a plurality of partition walls;

the step of forming the at least 1 optical waveguide includes a step of providing 1 or more dielectric members between the plurality of partition walls, and the step of providing 1 or more dielectric members is performed after the step of forming the plurality of partition walls.

19. The method of manufacturing an optical device according to claim 17,

further comprising a step of forming a plurality of partition walls;

the step of forming the at least 1 optical waveguide further includes a step of injecting 1 or more dielectric members including a liquid crystal material between the plurality of partition walls, and the step of injecting the 1 or more dielectric members including a liquid crystal material is performed after the step of fixing the 1 st substrate and the 2 nd substrate.

Technical Field

The invention relates to an optical device, an optical detection system and a method of manufacturing the same.

Background

Various apparatuses capable of scanning (scan) a space with light have been proposed in the past.

Patent document 1 discloses a configuration capable of scanning light passing through a mirror using a driving device for rotating the mirror.

Patent document 2 discloses an optical phased array having a plurality of nanophotonic antenna elements arranged two-dimensionally. Each antenna element is optically coupled to a variable optical delay line (i.e., a phase shifter). In the optical phased array, coherent light beams are guided to respective antenna elements through waveguides, and the phases of the light beams are shifted by phase shifters. This enables the amplitude distribution of the far-field radiation pattern to be changed.

Patent document 3 discloses an optical deflection element including: an optical waveguide having an optical waveguide layer for guiding light inside and 1 st distributed Bragg mirrors formed on upper and lower surfaces of the optical waveguide layer; a light incident port for allowing light to be incident into the optical waveguide; and a light exit port formed on a surface of the optical waveguide so as to emit light that enters from the light entrance port and is guided in the optical waveguide.

Documents of the prior art

Patent document

Patent document 1: international publication No. 2013/168266

Patent document 2: japanese patent laid-open publication No. 2016-508235

Patent document 3: japanese patent laid-open publication No. 2013-16591

Disclosure of Invention

Problems to be solved by the invention

The invention provides a novel optical device including an optical waveguide having high dimensional accuracy.

Means for solving the problems

An optical device according to an aspect of the present invention includes: a 1 st substrate having a 1 st surface extending in a 1 st direction and a 2 nd direction intersecting the 1 st direction; a 2 nd substrate having a 2 nd surface at least partially opposed to the 1 st surface; at least 1 optical waveguide extending in the 1 st direction between the 1 st substrate and the 2 nd substrate; and a plurality of elastic spacers, which are disposed on at least one of the 1 st surface and the 2 nd surface, and include a 1 st portion and a 2 nd portion. The 2 nd surface has a different area from the 1 st surface. The 1 st portion of the plurality of elastic spacers is at least 1 elastic spacer located between the 1 st substrate and the 2 nd substrate and in a region where the 1 st substrate and the 2 nd substrate overlap when viewed from a direction perpendicular to the 1 st surface. The 2 nd portion of the plurality of elastic spacers is at least 1 elastic spacer located in a region where the 1 st substrate and the 2 nd substrate do not overlap when viewed from a direction perpendicular to the 1 st surface.

The inclusion or specific aspects of the present invention may also be achieved by an apparatus, system, method, or any combination thereof.

Effects of the invention

According to an aspect of the present invention, an optical device including an optical waveguide with high dimensional accuracy can be realized.

Drawings

Fig. 1 is a perspective view schematically showing the structure of an optical scanning apparatus.

Fig. 2 is a diagram schematically showing an example of the structure of the cross section of one waveguide element and light propagating.

Fig. 3A is a view showing a cross section of the waveguide array that emits light in a direction perpendicular to an emission surface of the waveguide array.

Fig. 3B is a view showing a cross section of the waveguide array that emits light in a direction different from a direction perpendicular to the emission surface of the waveguide array.

Fig. 4 is a perspective view schematically showing a waveguide array in a three-dimensional space.

Fig. 5 is a schematic view of the waveguide array and the phase shifter array viewed from the normal direction (Z direction) of the light exit surface.

Fig. 6 is a view schematically showing an example of a lower structure of the optical device when viewed from the Z direction.

Fig. 7A is a view showing a cross section taken along line a-a shown in fig. 6.

Fig. 7B is a view showing a cross section taken along line B-B shown in fig. 6.

Fig. 7C is a cross-sectional view taken along line C-C of fig. 6.

Fig. 8A is a diagram schematically showing an example of an optical device in which the lower structure and the upper structure shown in fig. 7A are bonded.

Fig. 8B is a diagram schematically showing an example of an optical device in which the lower structure and the upper structure shown in fig. 7B are bonded.

Fig. 8C is a diagram schematically showing an example of an optical device in which the lower structure and the upper structure shown in fig. 7C are bonded.

Fig. 9 is a view schematically showing an example of the lower structure of the optical device of the present embodiment when viewed from the Z direction.

Fig. 10A is a view showing a cross section taken along line a-a shown in fig. 9.

Fig. 10B is a view showing a cross section taken along line B-B shown in fig. 9.

Fig. 10C is a cross-sectional view taken along line C-C of fig. 9.

Fig. 11A is a diagram schematically showing an example of an optical device in which the lower structure and the upper structure shown in fig. 10A are bonded.

Fig. 11B is a diagram schematically showing an example of an optical device in which the lower structure and the upper structure shown in fig. 10B are bonded.

Fig. 11C is a diagram schematically showing an example of an optical device in which the lower structure and the upper structure shown in fig. 10C are bonded.

Fig. 12A is a diagram schematically showing an example of an optical device in which the unnecessary portion is cut after the lower structure and the upper structure shown in fig. 11A are bonded.

Fig. 12B is a diagram schematically showing an example of an optical device in which the unnecessary portion is cut after the lower structural body and the upper structural body shown in fig. 11B are bonded.

Fig. 13 is a diagram showing a configuration of an optical scanning apparatus according to a modification.

Fig. 14 is a diagram schematically showing light emission from an optical device.

Fig. 15 is a flowchart showing a manufacturing process of the optical device.

Fig. 16 is a diagram showing an example of the configuration of an optical scanning device in which elements such as a beam splitter, a waveguide array, a phase shifter array, and a light source are integrated on a circuit substrate.

Fig. 17 is a schematic diagram showing a state where two-dimensional scanning is performed by irradiating a laser beam such as a laser beam from an optical scanning device to a far side.

FIG. 18 is a block diagram showing an example of a configuration of a LiDAR system capable of generating ranging images.

Detailed Description

In the present specification, "at least one of the refractive index, the thickness, and the wavelength" means at least one selected from the group consisting of the refractive index of the optical waveguide layer, the thickness of the optical waveguide layer, and the wavelength input to the optical waveguide layer. In order to change the light emission direction, any one of the refractive index, the thickness, and the wavelength may be controlled independently. Alternatively, any two or all of the 3 may be controlled to change the light emission direction. In each of the following embodiments, the wavelength of light input to the optical waveguide layer may be controlled instead of or in addition to the control of the refractive index or the thickness.

The basic principle described above can be applied not only to the use of emitting light but also to the use of receiving optical signals. By changing at least one of the refractive index, the thickness, and the wavelength, the direction of the receivable light can be changed in one dimension. Further, if the phase difference of light is changed by a plurality of phase shifters respectively connected to a plurality of waveguide elements arranged in one direction, the direction of receivable light can be changed two-dimensionally.

The optical scanning device and the optical receiving device according to the embodiments of the present invention can be used as an antenna of a light Detection system such as a lidar (light Detection and ranging) system. The LiDAR system uses electromagnetic waves having a shorter wavelength (visible light, infrared light, or ultraviolet light) than a radar system using radio waves such as millimeter waves, and thus can detect the distance distribution of an object with a higher resolving power. Such a LiDAR system is mounted on, for example, an automobile or a UAV (Unmanned aerial vehicle)_ia moving body such as an unmanned aerial Vehicle (so-called "drone"), an automated Guided Vehicle (agv), and the like can be used as one of the collision avoidance techniques. In this specification, the optical scanning device and the light receiving device may be collectively referred to as an "optical device". Further, as for a device used in an optical scanning device or an optical receiving device, there is also a case of being referred to as an "optical device".

< example of Structure of optical scanning apparatus >

The following describes, as an example, a configuration of an optical scanning device that performs two-dimensional scanning. However, the above detailed description may be omitted. For example, detailed descriptions of already known matters and repetitive descriptions of substantially the same configuration may be omitted. This is to avoid unnecessarily lengthy descriptions that will be presented below to facilitate understanding by those skilled in the art. The present inventors have provided the drawings and the following description in order to fully understand the present invention, and do not intend to limit the subject matter described in the claims. In the following description, the same or similar components are denoted by the same reference numerals.

In the present invention, "light" means electromagnetic waves including not only visible light (having a wavelength of about 400nm to about 700nm), but also ultraviolet light (having a wavelength of about 10nm to about 400nm) and infrared light (having a wavelength of about 700nm to about 1 mm). In the present specification, ultraviolet light may be referred to as "ultraviolet light" and infrared light may be referred to as "infrared light".

In the present invention, "scanning" based on light means changing the direction of light. The "one-dimensional scanning" means that the direction of light is linearly changed along a direction intersecting with the direction. "two-dimensional scanning" means that the direction of light is changed two-dimensionally along a plane intersecting the direction.

Fig. 1 is a perspective view schematically showing the structure of an optical scanning apparatus 100 of the embodiment. The optical scanning device 100 is provided with a waveguide array including a plurality of waveguide elements 10. Each of the plurality of waveguide elements 10 has a shape extending in the 1 st direction (X direction in fig. 1). The plurality of waveguide elements 10 are regularly arranged in a 2 nd direction (Y direction in fig. 1) intersecting the 1 st direction. The plurality of waveguide elements 10 emit light in the 3 rd direction D3 intersecting a virtual plane parallel to the 1 st and 2 nd directions while propagating the light in the 1 st direction. The 1 st direction (X direction) is orthogonal to the 2 nd direction (Y direction), but may not be orthogonal to each other. The plurality of waveguide elements 10 are arranged at equal intervals in the Y direction, but need not be arranged at equal intervals.

The orientation of the structure shown in the drawings of the present application is set in consideration of ease of understanding of the description, and is not at all limited to the orientation of the structure in actual implementation. The shape and size of the whole or a part of the structure shown in the drawings are not limited to actual shapes and sizes.

Each of the plurality of waveguide elements 10 includes a 1 st mirror 30 and a 2 nd mirror 40 (hereinafter, each will be simply referred to as a "mirror") facing each other, and an optical waveguide layer 20 located between the mirrors 30 and 40. Each of the mirrors 30 and 40 has a reflecting surface intersecting the 3 rd direction D3 at an interface with the optical waveguide layer 20. The mirrors 30 and 40 and the optical waveguide layer 20 have a shape extending in the 1 st direction (X direction).

As will be described later, the 1 st mirrors 30 of the waveguide elements 10 may be integrally formed as a plurality of portions of a mirror. The plurality of 2 nd mirrors 40 of the plurality of waveguide elements 10 may be a plurality of portions of a mirror integrally configured. Further, the plurality of optical waveguide layers 20 of the plurality of waveguide elements 10 may be a plurality of portions of an integrally configured optical waveguide layer. A plurality of waveguides can be formed by at least (1) configuring each 1 st mirror 30 separately from the other 1 st mirrors 30, (2) configuring each 2 nd mirror 40 separately from the other 2 nd mirrors 40, or (3) configuring each optical waveguide layer 20 separately from the other optical waveguide layers 20. The term "divided structure" includes not only a physical space but also a structure separated from each other with a material having a different refractive index interposed therebetween.

The reflection surface of the 1 st mirror 30 and the reflection surface of the 2 nd mirror 40 are substantially parallel to each other. Of the two mirrors 30 and 40, at least the 1 st mirror 30 has a characteristic of transmitting a part of light propagating through the optical waveguide layer 20. In other words, the 1 st mirror 30 has a higher light transmittance for the light than the 2 nd mirror 40. Therefore, a part of the light propagating through the optical waveguide layer 20 is emitted from the 1 st mirror 30 to the outside. Such mirrors 30 and 40 may be multilayer film mirrors formed of a dielectric multilayer film (also referred to as a "multilayer reflective film"), for example.

By controlling the phase of light input to each waveguide 10, the refractive index or thickness of the optical waveguide layer 20 of the waveguide 10 or the wavelength of light input to the optical waveguide layer 20 can be simultaneously changed in synchronization with each other, and two-dimensional scanning by light can be realized.

The present inventors analyzed the operation principle of the waveguide element 10 in order to realize such two-dimensional scanning. Based on the result, the two-dimensional scanning by light is successfully achieved by driving the plurality of waveguide elements 10 in synchronization.

As shown in fig. 1, if light is input to each waveguide element 10, the light is emitted from the emission surface of each waveguide element 10. The exit surface is located on the opposite side of the reflection surface of the 1 st mirror 30. The direction D3 of the emitted light depends on the refractive index and thickness of the optical waveguide layer and the wavelength of the light. At least one of the refractive index, thickness, and wavelength of each optical waveguide layer is synchronously controlled so that the light emitted from each waveguide element 10 is in substantially the same direction. This enables the component in the X direction of the wave number vector of the light emitted from the plurality of waveguide elements 10 to be changed. In other words, the direction D3 of the emitted light can be changed along the direction 101 shown in fig. 1.

Further, since the light emitted from the plurality of waveguide elements 10 is directed in the same direction, the emitted light interferes with each other. By controlling the phase of the light emitted from each waveguide element 10, the direction in which the lights mutually reinforce by interference can be changed. For example, when a plurality of waveguide elements 10 having the same size are arranged at equal intervals in the Y direction, light having a certain phase difference is input to each of the plurality of waveguide elements 10. By changing this phase difference, the component in the Y direction of the wave number vector of the emitted light can be changed. In other words, by changing the phase difference of the light introduced into each of the plurality of waveguide elements 10, the direction D3 in which the emitted lights mutually reinforce each other by interference can be changed along the direction 102 shown in fig. 1. This enables two-dimensional scanning by light.

The operation principle of the optical scanning apparatus 100 is explained below.

< principle of operation of waveguide element >

Fig. 2 is a diagram schematically showing an example of the structure of the cross section of one waveguide element 10 and light propagating. Fig. 2 schematically shows a cross section of the waveguide element 10 parallel to the XZ plane, with the Z direction being a direction perpendicular to the X direction and the Y direction shown in fig. 1. In the waveguide element 10, a pair of mirrors 30 and 40 is disposed so as to sandwich the optical waveguide layer 20. The light 22 introduced from one end of the optical waveguide layer 20 in the X direction propagates through the optical waveguide layer 20 while being repeatedly reflected by the 1 st mirror 30 provided on the upper surface (upper surface in fig. 2) of the optical waveguide layer 20 and the 2 nd mirror 40 provided on the lower surface (lower surface in fig. 2). The light transmittance of the 1 st mirror 30 is higher than that of the 2 nd mirror 40. Therefore, a part of the light can be mainly output from the 1 st mirror 30.

In a waveguide such as a normal optical fiber, light propagates along the waveguide while repeating total reflection. In contrast, in the waveguide element 10 of the present invention, light propagates while being repeatedly reflected by the mirrors 30 and 40 disposed above and below the optical waveguide layer 20. Therefore, there is no restriction on the propagation angle of light. Here, the propagation angle of light is an incident angle directed to the interface of the mirror 30 or the mirror 40 with the optical waveguide layer 20. Light incident at an angle closer to normal to either mirror 30 or mirror 40 can also propagate. That is, light incident on the interface at an angle smaller than the critical angle of total reflection can also propagate. Therefore, the group velocity of light in the propagation direction of light is greatly reduced compared to the velocity of light in free space. Thus, the waveguide element 10 has the following properties: the propagation condition of light greatly changes with respect to the wavelength of light, the thickness of the optical waveguide layer 20, and the refractive index of the optical waveguide layer 20. Such a waveguide is referred to as a "reflection waveguide" or a "slow light waveguide".

The emission angle θ of light emitted from the waveguide 10 into the air is represented by the following formula (1).

[ numerical formula 1]

As can be seen from the formula (1), the wavelength λ of light in the air and the refractive index n of the optical waveguide layer 20 are changed_wAnd the thickness d of the optical waveguide layer 20, the light emission direction can be changed.

For example, at n_wWhen d is 387nm, λ is 1550nm, and m is 1, the emission angle is 0 °. If the refractive index is changed from this state to n_wThe output angle change is about 66 °, 2.2. On the other hand, if the thickness is changed to d of 420nm without changing the refractive index, the emission angle is changed to about 51 °. If the wavelength change λ is 1500nm without changing both the refractive index and the thickness, the emission angle change is about 30 °. By setting the wavelength λ of light and the refractive index n of the optical waveguide layer 20 in this manner_wAnd the thickness d of the optical waveguide layer 20 can be changedThe light emission direction can be changed greatly.

Therefore, the optical scanning device 100 controls the wavelength λ of the light inputted to the optical waveguide layer 20 and the refractive index n of the optical waveguide layer 20_wAnd the thickness d of the optical waveguide layer 20, to control the light emission direction. The wavelength λ of light may be maintained constant without changing during operation. In this case, the scanning of light can be realized with a simpler structure. The wavelength λ is not particularly limited. For example, the wavelength λ may be included in a wavelength region of 400nm to 1100nm (from visible light to near-infrared light) that can obtain high detection sensitivity by a general photodetector or image sensor that detects light by absorbing light with silicon (Si). In another example, the wavelength λ may be included in a wavelength region of 1260nm to 1625nm, which has a relatively small transmission loss in an optical fiber or a Si waveguide. These wavelength ranges are examples. The wavelength range of the light used is not limited to the wavelength range of visible light or infrared light, and may be, for example, the wavelength range of ultraviolet light.

In order to change the direction of the emitted light, the optical scanning apparatus 100 may include a 1 st adjusting element that changes at least one of the refractive index, thickness, and wavelength of the optical waveguide layer 20 in each waveguide element 10.

As described above, if the waveguide element 10 is used, the refractive index n of the optical waveguide layer 20 is adjusted_wThe emission direction of light can be greatly changed by changing at least one of the thickness d and the wavelength λ. This allows the exit angle of the light emitted from the mirror 30 to be changed in the direction along the waveguide 10. Such a one-dimensional scanning can be achieved by using at least one waveguide element 10.

In order to adjust the refractive index of at least a portion of optical waveguide layer 20, optical waveguide layer 20 may also include a liquid crystal material or an electro-optic material. The optical waveguide layer 20 can be sandwiched by a pair of electrodes. By applying a voltage to the pair of electrodes, the refractive index of the optical waveguide layer 20 can be changed.

In order to adjust the thickness of the optical waveguide layer 20, at least one actuator may be connected to at least one of the 1 st mirror 30 and the 2 nd mirror 40, for example. The thickness of the optical waveguide layer 20 can be varied by varying the distance between the 1 st mirror 30 and the 2 nd mirror 40 by at least one actuator. The thickness of the optical waveguide layer 20 can be easily varied if the optical waveguide layer 20 is formed of a liquid.

< operation principle of two-dimensional scanning >

In a waveguide array in which a plurality of waveguide elements 10 are arranged in one direction, the emission direction of light changes due to interference of light emitted from each waveguide element 10. By adjusting the phase of the light supplied to each waveguide element 10, the light emission direction can be changed. The principle of this will be described below.

Fig. 3A is a view showing a cross section of the waveguide array that emits light in a direction perpendicular to an emission surface of the waveguide array. Fig. 3A also shows the phase shift amount of light propagating through each waveguide element 10. Here, the phase shift amount is a value based on the phase of light propagating through the left waveguide element 10. The waveguide array includes a plurality of waveguide elements 10 arranged at equal intervals. In fig. 3A, the circular arcs of the broken lines indicate the wave surfaces of the light emitted from the waveguide elements 10. The straight line indicates a wave surface formed by interference of light. The arrows indicate the direction of light exiting the waveguide array (i.e., the direction of the wavenumber vector). In the example of fig. 3A, the phases of light propagating through the optical waveguide layers 20 in the respective waveguide elements 10 are the same. In this case, the light is emitted in a direction (Z direction) perpendicular to both the arrangement direction (Y direction) of the waveguide elements 10 and the direction (X direction) in which the optical waveguide layer 20 extends.

Fig. 3B is a view showing a cross section of the waveguide array that emits light in a direction different from a direction perpendicular to the emission surface of the waveguide array. In the example shown in fig. 3B, the phases of the light propagating through the optical waveguide layers 20 in the plurality of waveguide elements 10 differ from each other by a certain amount in the arrangement directionIn this case, the light is emitted in a direction different from the Z direction. By making theThe component in the Y direction of the wave number vector of light can be changed. If it is adjacent toP is the center-to-center distance between the two waveguide elements 10, the light emission angle α is₀Represented by the following formula (2).

[ numerical formula 2]

In the example shown in fig. 2, the light emission direction is parallel to the XZ plane. I.e. alpha₀0 deg.. In the example shown in fig. 3A and 3B, the direction of light emitted from the optical scanning apparatus 100 is parallel to the YZ plane. That is, θ is 0 °. However, in general, the direction of light emitted from the light scanning apparatus 100 is neither parallel to the XZ plane nor parallel to the YZ plane. I.e., θ ≠ 0 ° and α₀≠0°。

Fig. 4 is a perspective view schematically showing a waveguide array in a three-dimensional space. The thick arrows shown in fig. 4 indicate the direction of light emitted from the optical scanning apparatus 100. θ is an angle formed by the light emission direction and the YZ plane. Theta satisfies the formula (1). Alpha is alpha₀Is the angle that the light exits from the XZ plane. Alpha is alpha₀Satisfies the formula (2).

< phase control of light introduced into waveguide array >

In order to control the phase of the light emitted from each waveguide element 10, for example, a phase shifter for changing the phase of the light may be provided before the light is introduced into the waveguide element 10. The optical scanning apparatus 100 includes a plurality of phase shifters connected to the plurality of waveguide elements 10, respectively, and a 2 nd adjusting element for adjusting a phase of light propagating through each of the phase shifters. Each phase shifter includes a waveguide connected to the optical waveguide layer 20 in a corresponding one of the plurality of waveguide elements 10, directly or via another waveguide. The 2 nd adjustment element changes the direction of light emitted from the plurality of waveguide elements 10 (i.e., the 3 rd direction D3) by changing the phase difference of light propagating from the plurality of phase shifters to the plurality of waveguide elements 10, respectively. In the following description, a plurality of phase shifters arranged in a similar manner to the waveguide array may be referred to as a "phase shifter array".

Fig. 5 is a schematic diagram of the waveguide array 10A and the phase shifter array 80A viewed from the normal direction (Z direction) of the light exit surface. In the example shown in fig. 5, all the phase shifters 80 have the same propagation characteristic, and all the waveguide elements 10 have the same propagation characteristic. The phase shifters 80 and the waveguide elements 10 may have the same length, or may have different lengths. In the case where the lengths of the respective phase shifters 80 are equal, the respective phase shift amounts can be adjusted by the driving voltage, for example. Further, by configuring the phase shifters 80 to change their lengths in equal steps, equal-step phase shifts can be applied with the same drive voltage. The optical scanning device 100 further includes an optical splitter 90 that branches light and supplies the light to the plurality of phase shifters 80, a 1 st drive circuit 110 that drives each waveguide element 10, and a 2 nd drive circuit 210 that drives each phase shifter 80. The straight arrows in fig. 5 indicate the input of light. By independently controlling the 1 st drive circuit 110 and the 2 nd drive circuit 210 provided separately, respectively, two-dimensional scanning can be realized. In this example, the 1 st drive circuit 110 functions as one element of the 1 st adjustment element, and the 2 nd drive circuit 210 functions as one element of the 2 nd adjustment element.

The 1 st drive circuit 110 changes at least one of the refractive index and the thickness of the optical waveguide layer 20 in each waveguide element 10, thereby changing the angle of light emitted from the optical waveguide layer 20. The 2 nd drive circuit 210 changes the phase of light propagating through the optical waveguide 20a by changing the refractive index of the optical waveguide 20a in each phase shifter 80. The beam splitter 90 may be constituted by a waveguide through which light propagates by total reflection, or may be constituted by a reflection waveguide similar to the waveguide element 10.

Further, the respective lights branched by the beam splitter 90 may be controlled in phase and then introduced into the phase shifter 80. For this phase control, for example, a simple phase control structure can be used which is realized by adjusting the length of the waveguide up to the phase shifter 80. Alternatively, a phase shifter having the same function as the phase shifter 80 and capable of being controlled by an electric signal may be used. By such a method, for example, before being introduced into the phase shifters 80, the phase may be adjusted so that light of equal phase is supplied to all the phase shifters 80. By such adjustment, the control of each phase shifter 80 by the 2 nd drive circuit 210 can be simplified.

An optical device having the same configuration as the optical scanning device 100 described above can also be used as a light receiving device. Details of the operation principle, operation method, and the like of the optical device are disclosed in U.S. patent application publication No. 2018/0224709. The entire disclosure of this document is incorporated into this specification.

< production of optical device by bonding >

The optical device 100 can be manufactured by, for example, attaching an upper structure provided with the 1 st mirror and a lower structure provided with the 2 nd mirror. For the bonding, for example, a sealing member made of an ultraviolet curable resin, a thermosetting resin, or the like can be used. For optical scanning based on voltage application, the photoconductive layer 20 may contain, for example, a liquid crystal material. For example, the optical device 100 may be sealed in a vacuum to inject the liquid crystal material. If the liquid crystal material is injected into the space surrounded by the sealing member, vacuum leakage can be prevented when the liquid crystal material is injected.

Fig. 6 is a view schematically showing an example of the lower structure 100a of the optical device 100 when viewed from the Z direction. Fig. 7A to 7C are views showing the line a-a, the line B-B, and the line C-C shown in fig. 6, respectively. Fig. 7A to 7C schematically illustrate examples of the lower structure 100a and the upper structure 100b of the optical device 100. The downward arrows shown in fig. 7A to 7C indicate the bonding direction.

After the lower structure 100a and the upper structure 100b are bonded, the liquid crystal material is injected from the sealing port 79o shown in fig. 6. Then, the seal opening 79o is closed by the same member as the seal member 79. The lower structure 100a includes a substrate 50a, an electrode 62a, a mirror 40, a dielectric layer 51, a plurality of optical waveguides 11, a plurality of partition walls 73, and a sealing member 79. The upper structure 100b includes a substrate 50b, an electrode 62b, and a mirror 30. Details of these are described later.

Fig. 8A to 8C are views each showing an example of the optical device 100 in which the lower structure 100a and the upper structure 100b shown in fig. 7A to 7C are bonded. As shown in fig. 8A to 8C, even if the lower structure 100a and the upper structure 100b are bonded in parallel, the substrate 50a and the substrate 50b may not be parallel in practice. This is because, when the upper structure 100b and the lower structure 100a are joined, the portion where the upper structure 100b and the lower structure 100a first contact each other serves as a fulcrum. For example, a portion where the sealing member 79 contacts the electrode 62b, or a portion where 1 of the plurality of partition walls 73 contacts the mirror 30 serves as a fulcrum. If the force applied to the upper structure 100b is not uniform during bonding, the distance between the substrate 50a and the substrate 50b differs between a portion closer to the supporting point and a portion farther from the supporting point. For example, in a portion farther from the fulcrum, the distance between the substrate 50a and the substrate 50b is larger than in a portion closer to the fulcrum. Therefore, the substrate 50a and the substrate 50b may not be parallel. In this case, the intensity of light emitted from the optical device 100 and the emission angle of light may deviate from the design values.

The inventors of the present invention have conceived of the optical device described in the following items based on the above studies.

The optical device according to item 1 includes: a 1 st substrate having a 1 st surface extending in a 1 st direction and a 2 nd direction intersecting the 1 st direction; a 2 nd substrate having a 2 nd surface at least partially opposed to the 1 st surface; at least 1 optical waveguide extending in the 1 st direction between the 1 st substrate and the 2 nd substrate; and a plurality of elastic spacers, which are disposed on at least one of the 1 st surface and the 2 nd surface, and include a 1 st portion and a 2 nd portion. The 2 nd surface has a different area from the 1 st surface. The 1 st portion of the plurality of elastic spacers is at least 1 elastic spacer located between the 1 st substrate and the 2 nd substrate and in a region where the 1 st substrate and the 2 nd substrate overlap when viewed from a direction perpendicular to the 1 st surface. The 2 nd portion of the plurality of elastic spacers is at least 1 elastic spacer located in a region where the 1 st substrate and the 2 nd substrate do not overlap when viewed from a direction perpendicular to the 1 st surface.

In the optical apparatus, the interval between the 1 st substrate and the 2 nd substrate can be made uniform by the 1 st portions of the plurality of elastic spacers. As a result, the accuracy of the intensity of the emitted light and the emission angle can be greatly improved. Further, the 2 nd portions of the plurality of elastic spacers can protect the components provided in the region where the 1 st substrate and the 2 nd substrate do not overlap from external contact.

The optical device according to item 2 further includes a plurality of partition walls extending in the 1 st direction in the optical device according to item 1. The plurality of partition walls are arranged in the 2 nd direction between the 1 st substrate and the 2 nd substrate. The elastic spacers have a lower elastic modulus than the partition walls.

In this optical device, the interval between the 1 st substrate and the 2 nd substrate becomes uniform as a whole by the elastic spacer which acts and compresses like a spring.

The optical device according to item 3 is the optical device according to item 2, wherein the plurality of partition walls are directly or indirectly sandwiched between the 1 st substrate and the 2 nd substrate. The 1 st substrate and the 2 nd substrate are sandwiched, and a deformation ratio of each of the plurality of elastic spacers in a direction perpendicular to the 1 st surface is larger than a deformation ratio of each of the plurality of partition walls in the perpendicular direction.

In the optical device, the deformation ratio of each spacer is larger than that of each partition wall, so that the interval between the 1 st substrate and the 2 nd substrate becomes uniform as a whole.

The optical device according to item 4 is the optical device according to any one of items 1 to 3, wherein the plurality of elastic spacers each have a columnar shape.

In this optical device, the same effects as those of the optical device relating to items 1 to 3 can be obtained.

The optical device according to claim 5 is the optical device according to any one of claims 1 to 4, wherein the at least 1 optical waveguide includes: a 1 st portion disposed between the 1 st substrate and the 2 nd substrate and in a region where the 1 st substrate and the 2 nd substrate overlap; and a 2 nd portion disposed in a region where the 1 st substrate and the 2 nd substrate do not overlap.

In the optical device, light can be input from the 2 nd part to the 1 st part.

The optical device according to item 6 is the optical device according to item 5, wherein the at least one optical waveguide is a plurality of optical waveguides. At least a part of the 2 nd portion of the plurality of elastic spacers is positioned around the 2 nd portion of each of the plurality of optical waveguides.

In the optical device, the 2 nd portions of the plurality of optical waveguides can be protected from external contact by at least a part of the 2 nd portions of the plurality of elastic spacers.

The optical device according to item 7 is the optical device according to item 5 or 6, wherein the at least one optical waveguide includes a portion located between two adjacent partition walls, and the portion includes a 1 st grating.

In the optical device, light propagating in the optical waveguide can be coupled with high efficiency via the 1 st grating.

The optical device according to claim 8 is the optical device according to any one of claims 5 to 7, wherein the at least one optical waveguide includes a 2 nd grating in the 2 nd portion.

In this optical device, light can be input from the outside to the optical waveguide via the 2 nd grating with high efficiency.

The optical device according to claim 9 further includes a sealing member that fixes a gap between the 1 st substrate and the 2 nd substrate in the optical device according to any one of claims 1 to 8. The at least 1 optical waveguide has a structure in which 1 or more 1 st optical waveguides and 1 or more 2 nd optical waveguides are connected to each other. The sealing member surrounds the 1 st or more optical waveguides 1 when viewed from a direction perpendicular to the 1 st surface.

In this optical device, 1 or more 1 st optical waveguides can be sealed with the 1 st substrate, the 2 nd substrate, and the sealing member.

The optical device according to item 10 is the optical device according to item 9, wherein the 1 or more 1 st optical waveguides include 1 or more dielectric members extending in the 1 st direction, respectively. The region between the 1 st substrate and the 2 nd substrate and surrounded by the sealing member is filled with the same members as the 1 or more dielectric members.

In this optical device, the space enclosed by the 1 st substrate, the 2 nd substrate, and the sealing member is filled with the same member as the 1 or more dielectric members, whereby the 1 or more 1 st optical waveguides can be easily manufactured.

The optical device according to claim 11 is the optical device according to any one of claims 1 to 10, wherein the 1 or more 1 st optical waveguides include 1 or more dielectric members extending in the 1 st direction, respectively. The optical device further includes 2 mirrors, and the 2 mirrors are respectively located between the 1 st substrate and the 1 or more dielectric members, and between the 2 nd substrate and the 1 or more dielectric members.

In this optical device, each 1 st optical waveguide functions as a reflective waveguide by 2 mirrors. This allows light propagating through each 1 st optical waveguide to be emitted to the outside.

The optical device according to item 12 is the optical device according to item 11, wherein at least a part of the 1 st portion of the plurality of elastic spacers is located outside a region sandwiched between the 2 mirrors.

In this optical device, even if particles are mixed outside the region sandwiched by the 2 mirrors, the distance between the 1 st substrate and the 2 nd substrate in the direction perpendicular to the 1 st surface in the region is large, and therefore the distance between the 1 st substrate and the 2 nd substrate after bonding can be made uniform.

The optical device according to claim 13 is the optical device according to any one of claims 10 to 12, wherein the 1 or more 1 st optical waveguides include a structure capable of adjusting a refractive index of the 1 or more dielectric members. By adjusting the refractive index of the 1 or more dielectric members, the direction of light emitted from the 1 or more 1 st optical waveguides through the 1 st substrate or the 2 nd substrate or the direction of light incident into the 1 or more 1 st optical waveguides through the 1 st substrate or the 2 nd substrate changes.

In this optical device, a light scanning device capable of changing the light emission direction or a light receiving device capable of changing the light receiving direction can be realized.

The optical device according to claim 14 is the optical device according to claim 13, further comprising a pair of electrodes sandwiching the 1 or more dielectric members. The 1 or more dielectric members include a liquid crystal material or an electro-optical material. The refractive index of the 1 or more dielectric members is adjusted by applying a voltage to the pair of electrodes.

In this optical device, the optical device according to item 13 can be realized by voltage application.

The optical device according to claim 15 further includes 1 or more phase shifters directly connected to the 1 st or more optical waveguides 1 or connected to the optical waveguides via another waveguide, respectively, in the optical device according to claim 14. By changing the phase difference of the light passing through the 1 or more phase shifters, the direction of the light emitted from the 1 or more 1 st optical waveguides via the 1 st substrate or the 2 nd substrate or the direction of the light incident on the 1 or more 1 st optical waveguides via the 1 st substrate or the 2 nd substrate is changed.

In this optical device, an optical scanning device capable of independently changing the light emission direction in 2 directions by 1 or more phase shifters or an optical receiving device capable of independently changing the light receiving direction in 2 directions can be realized.

The photodetection system according to item 16 includes: the optical device according to any one of items 1 to 15; a photodetector for detecting light emitted from the optical device and reflected from an object; and a signal processing circuit for generating distance distribution data based on the output of the photodetector.

In this photodetection system, distance distribution data of the object can be obtained by measuring the time when the light reflected from the object returns.

The method of manufacturing an optical device according to item 17, comprising: preparing a 1 st substrate having a 1 st surface and a 2 nd substrate having a 2 nd surface; forming at least 1 optical waveguide extending in one direction on the 1 st surface of the 1 st substrate; forming a plurality of elastic spacers on the 1 st surface of the 1 st substrate or the 2 nd surface of the 2 nd substrate; a step of fixing the 1 st substrate and the 2 nd substrate by opposing the 1 st surface of the 1 st substrate and the 2 nd surface of the 2 nd substrate so that the plurality of elastic spacers are positioned around the at least 1 optical waveguide; and cutting and removing a part of the substrate, which is not provided with the plurality of elastic spacers, out of the 1 st substrate or the 2 nd substrate, to expose a part of the plurality of elastic spacers.

The optical device of item 1 can be manufactured by the method for manufacturing an optical device.

The method of manufacturing an optical device according to item 18 further includes a step of forming a plurality of partition walls in the method of manufacturing an optical device according to item 17. The step of forming the at least 1 optical waveguide includes a step of providing 1 or more dielectric members between the plurality of partition walls, and the step of providing 1 or more dielectric members is performed after the step of forming the plurality of partition walls.

In the method of manufacturing an optical device, 1 or more optical waveguides each having 1 or more dielectric members can be formed between the plurality of partition walls.

The method of manufacturing an optical device according to item 19 further includes a step of forming a plurality of partition walls in the method of manufacturing an optical device according to item 17. The step of forming the at least 1 optical waveguide further includes a step of injecting 1 or more dielectric members including a liquid crystal material between the plurality of partition walls, and the step of injecting the 1 or more dielectric members including a liquid crystal material is performed after the step of fixing the 1 st substrate and the 2 nd substrate.

In the method of manufacturing an optical device, 1 or more optical waveguides each having 1 or more dielectric members including a liquid crystal material can be formed between the plurality of partition walls.

Hereinafter, an optical device according to an exemplary embodiment of the present invention will be described.

(embodiment mode)

Fig. 9 is a plan view schematically showing an example of the lower structure 100a of the optical device 100 according to the present embodiment. Fig. 10A to 10C are views showing the line a-a, the line B-B, and the line C-C shown in fig. 9, respectively.

The optical device 100 includes a 1 st substrate 50a, a 2 nd substrate 50b, a plurality of partition walls 73, a plurality of 1 st optical waveguides 10, a plurality of elastic spacers 77, a sealing member 79, and a plurality of 2 nd optical waveguides 11. The number of the 1 st optical waveguides 10 is not limited, and may be 1. The same applies to the 2 nd optical waveguide 11 and the elastic spacer 77. In the following description, the "1 st substrate 50 a" and the "2 nd substrate 50 b" are referred to as a "substrate 50 a" and a "substrate 50 b", respectively, and the "1 st optical waveguide 10" and the "2 nd optical waveguide 11" are referred to as an "optical waveguide 10" and an "optical waveguide 11", respectively.

The optical device 100 of the present embodiment includes a lower structure 100a and an upper structure 100 b.

The lower structure 100a includes a substrate 50a, an electrode 62a, a mirror 40, a dielectric layer 51, a plurality of partition walls 73, a plurality of elastic spacers 77, a sealing member 79, and an optical waveguide 11. As shown in fig. 10A, the substrate 50A has a 1 st surface 50as extending in the X and Y directions. An electrode 62a is provided on the substrate 50 a. The mirror 40 is provided on the electrode 62 a. A dielectric layer 51 is provided on the mirror 40. The dielectric layer 51 is provided with partition walls 73, elastic spacers 77, a sealing member 79, and an optical waveguide 11.

The upper structure 100b includes a substrate 50b having a 2 nd surface 50bs, an electrode 62b, and a mirror 40. The 2 nd surface 50bs is opposed to the 1 st surface 50as of the substrate 50 a. The 2 nd surface 50bs has substantially the same area as the 1 st surface 50 as. An electrode 62b is provided on the substrate 50 b. The mirror 30 is provided on the electrode 62 b.

Of the substrates 50a and 50b, the substrate on the side from which light is emitted has light-transmitting properties. Both the substrate 50a and the substrate 50b may have optical transparency. Similarly, of the electrodes 62a and 62b, the electrode on the light emitting side has a light-transmitting property. Both the electrode 62a and the electrode 62b may have light-transmitting properties. At least one of the electrodes 62a and 62b may be formed of a transparent electrode, for example. In the examples shown in fig. 9 and fig. 10A to 10C, light is emitted from the optical waveguide 10 via the electrode 62b and the substrate 50b of the upper structure 100 b.

As shown in fig. 9, the plurality of partition walls 73 are positioned between the substrates 50a and 50b and arranged in the Y direction. Each partition wall 73 extends in the X direction.

The plurality of optical waveguides 10 are defined between the plurality of partition walls 73. Each optical waveguide 10 includes a dielectric member 21 extending in the X direction. Fig. 10A to 10C show a state before the material constituting the dielectric member 21 is injected. The dielectric member 21 includes, for example, a liquid crystal material or an electro-optical material. The optical waveguide 10 includes a mirror 30, a mirror 40, and a dielectric member 21. The dielectric member 21 is provided in a region surrounded by the mirrors 30 and 40 and the adjacent 2 partition walls 73. The optical waveguide 10 functions as the slow optical waveguide described above. The mirror 40 is located between the substrate 50a and the dielectric member 21. The mirror 30 is located between the substrate 50b and the dielectric member 21. The dielectric member 21 constitutes the optical waveguide layer 20 shown in fig. 2. In the example shown in fig. 9 and fig. 10A to 10C, a part of the dielectric layer 51 in the optical waveguide layer 20 is removed, and a part of the mirror 40 is exposed. The light guide layer 20 is formed in a region sandwiched by the mirror 30 and the mirror 40.

The refractive index of the dielectric member 21 is higher than the refractive indices of the partition walls 73 and the dielectric layer 51. Thus, light propagating through the optical waveguide layer 20 does not leak to the partition walls 73 and the dielectric layer 51 directly below the partition walls. The light propagating through the optical waveguide layer 20 is totally reflected at the interfaces between the optical waveguide layer 20 and the respective partitions 73 and at the interfaces between the optical waveguide layer 20 and the dielectric layers 51.

The pair of electrodes 62a and 62b directly or indirectly sandwich the dielectric member 21. "directly sandwich" means not sandwich other members. "indirectly sandwich" means sandwich via other members. By applying a voltage to the pair of electrodes 62a and 62b, the refractive index of the dielectric member 21 is adjusted. As a result, the emission angle of the light emitted from the optical waveguide 10 to the outside changes.

In addition, the optical waveguide 10 need not be a slow optical waveguide. The optical waveguide 10 may be a waveguide that propagates light by total reflection, for example. In this waveguide, light is emitted from the end of the optical waveguide 10 to the outside without passing through the substrate 50a or the substrate 50 b.

A plurality of elastomeric spacers 77 are positioned around the plurality of optical waveguides 10. In the example shown in fig. 9, a plurality of columnar elastic spacers 77 are two-dimensionally arranged. The configuration may be either regular or periodic, or irregular. The diameter of the elastic spacer 77 in the XY plane may be, for example, 10 μm or more and 100 μm or less. In the example shown in fig. 9, the elastic spacer 77 is located on both the inner side and the outer side of the region surrounded by the seal member 79. The elastic spacer 77 may be provided only on one of the inner side and the outer side of the region. Thus, the elastic spacer 77 is positioned at least on the inner side and the outer side of the region. A portion of the resilient spacer 77 may also be disposed within the optical waveguide layer 20. The elastic spacer 77 may have a shape in which 1 is connected to the inside and/or outside of the region surrounded by the seal member 79. The shape may be, for example, a linear shape, a curved shape, a wavy shape, or a zigzag shape when viewed from the Z direction.

In a state before the lower structure 100a and the upper structure 100b are bonded, the dimension of the elastic spacer 77 in the Z direction is larger than the sum of the dimensions of the partition wall 73 and the mirror 30 in the Z direction. Further, in this state, the dimension of the elastic spacer 77 in the Z direction is larger than the dimension of the seal member 79 in the Z direction. Therefore, when the lower structure 100a and the upper structure 100b are bonded, the electrode 62b of the upper structure 100b is first brought into contact with the elastic spacer 77 of the lower structure 100 a. Therefore, the portion of the sealing member 79 in contact with the electrode 62b or the portion of the partition wall 73 in contact with the mirror 30 does not serve as a fulcrum.

In the elastic spacer 77, elastic deformation occurs. In the case where a force is applied to the elastomer and a strain occurs, the modulus of elasticity is defined by dividing the applied force by the resulting strain. The elastic spacer 77 has a smaller elastic modulus than the partition wall 73 and the mirror 30. That is, the elastic spacer 77 is more easily deformed than the partition wall 73 and the mirror 30. When the lower structure 100a and the upper structure 100b are bonded, the elastic spacer 77 acts like a spring and is compressed. Thereby, the upper surface of the partition wall 73 is uniformly in contact with the reflection surface of the mirror 30, and the interval between the substrate 50a and the substrate 50b becomes uniform as a whole. As a result, the substrate 50a and the substrate 50b become substantially parallel. At this time, the elastic spacers are sandwiched between the substrate 50a and the substrate 50b, and the deformation ratio of the elastic spacers in the Z direction is larger than the deformation ratio of the partitions in the Z direction.

The sealing member 79 fixes the gap between the substrates 50a and 50 b. As shown in fig. 9, the sealing member 79 surrounds the plurality of optical waveguides 10 and the plurality of partition walls 73 when viewed from the Z direction. The sealing member 79 is provided across the optical waveguide 11 in the Y direction. The upper surface of the sealing member 79 is parallel to the XY plane. The dimension of the sealing member 79 in the Z direction on the dielectric layer 51 is equal to or larger than the sum of the dimension of the partition wall 73 and the dimension of the mirror 30 in the Z direction. The sealing member 79 may be formed of, for example, an ultraviolet curable resin or a thermosetting resin. The material of the sealing member 79 does not need to be an ultraviolet curing resin or a thermosetting resin as long as it can maintain the gap between the substrate 50a and the substrate 50b for a long period of time.

The optical waveguide 11 is connected to the optical waveguide 10. Light is supplied from the optical waveguide 11 to the optical waveguide 10. In the example shown in fig. 9 and fig. 10A to 10C, the optical waveguide 11 is located on the dielectric layer 51. The dielectric layer 51 is located between the substrate 50a and the optical waveguide 11. By adjusting the size of the dielectric layer 51 in the Z direction, light propagating through the optical waveguide 11 can be efficiently coupled to the optical waveguide 10. The size of the dielectric layer 51 in the Z direction can be adjusted, for example, so that the optical waveguide 11 is located near the center of the optical waveguide layer 20 in the Z direction. The optical waveguide 11 is a waveguide that propagates light by total reflection. Therefore, the refractive index of the optical waveguide 11 is higher than that of the dielectric layer 51. The optical waveguide 11 may be a slow optical waveguide.

The plurality of optical waveguides 11 are respectively provided with portions located between adjacent 2 partition walls among the plurality of partition walls 73. As shown in fig. 9 to 10C, each of the plurality of optical waveguides 11 includes a grating 15 in the portion. The propagation constant of the optical waveguide 11 is different from that of the optical waveguide 10. By the grating 15, the propagation constant of the optical waveguide 11 is shifted by the amount of the inverse lattice. When the propagation constant of the optical waveguide 11 shifted by the inverse lattice amount coincides with the propagation constant of the optical waveguide 10, the light propagating in the optical waveguide 11 is coupled with the optical waveguide 10 with high efficiency.

Fig. 11A to 11C are views schematically showing an example of the optical device 100 in a state in which the lower structure 100A and the upper structure 100b shown in fig. 10A to 10C are bonded to each other. As shown in fig. 11A to 11C, if the substrate 50a and the substrate 50b are bonded, the force is uniformly applied to the 1 st surface 50as and the 2 nd surface 50bs opposed to each other via the elastic spacer 77. Thereby, the substrate 50a and the substrate 50b become substantially parallel. The elastic spacer 77 is sandwiched directly or indirectly by the base plate 50a and the base plate 50 b. In the example shown in fig. 11A to 11C, the elastic spacer 77 is directly sandwiched between the dielectric layer 51 of the lower structure 100a and the electrode 62b of the upper structure 100 b. The dimension of the elastic spacer 77 in the Z direction is larger than the dimension of the partition wall 73 in the Z direction.

Fig. 12A and 12B are views schematically showing examples of cutting off a part of the substrate 50B and the electrode 62B shown in fig. 11A and 11B, respectively. By the cutting, a part of the periphery of the region surrounded by the seal member 79 is removed. As a result, the 2 nd surface 50bs has a different area from the 1 st surface 50 as. As shown in fig. 12A and 12B, the optical waveguide 11 has a portion overlapping the substrate 50a but not overlapping the substrate 50B when viewed from the Z direction. The optical waveguide 11 may be provided with a grating 13 at the non-overlapping portion. For the same reason as described above, when light is input through the grating 13, the input light can be coupled to the optical waveguide 11 with higher efficiency. The optical waveguide 11 may include a portion that overlaps the substrate 50b but does not overlap the substrate 50a, or may include a portion that does not overlap both the substrate 50a and the substrate 50 b. In this way, the optical waveguide 11 may have a portion that does not overlap with at least one of the substrate 50a and the substrate 50b when viewed from a direction perpendicular to the surface of each substrate. In this case, a part of the elastic spacer 77 remains on the dielectric layer 51 without being sandwiched between the substrate 50a and the substrate 50 b. The dimension in the Z direction of the part of the elastic spacer 77 is larger than the dimension in the Z direction of the remaining elastic spacer 77. The electrode 62a or 62b, the grating 13, and the optical waveguide 11 can be protected from external contact by the remaining elastic spacer 77.

The function of the elastic spacer 77 is summarized as follows. The elastic spacer 77 serves to make the substrates 50a and 50b parallel to each other when the optical device 100 is manufactured. The elastic spacer 77 plays a role of protecting a part of the components from external contact when the optical device 100 is used.

When the dielectric member 21 is made of a liquid crystal material, the liquid crystal material is injected from the sealing port 79o after the lower structure 100a and the upper structure 100b are bonded. After at least one of the bonded structures is partially cut, the liquid crystal material may be injected through the sealing port 79 o. After the liquid crystal material is injected, the seal opening 79o is closed with the same member as the seal member 79. The enclosed region is thus entirely filled with liquid crystal material. This region is a region located between the substrates 50a and 50b and surrounded by the sealing member 79. This area is filled with the same member as the dielectric member 21.

Hereinafter, an example of details of the materials and dimensions of the components used for manufacturing the optical device 100 will be described. Hereinafter, the dimension in the Z direction may be referred to as "thickness".

First, examples of the materials and dimensions of the components of the lower structure 100a will be described.

The substrate 50a may be made of, for example, SiO₂And (4) layer formation. The dimensions of the substrate 50a in the X direction and the Y direction may be both 15mm, for example. The thickness of the substrate 50a may be, for example, 0.7 mm.

The electrode 62a may be formed of, for example, an ITO sputtered layer. The thickness of the electrode 62a may be 50nm, for example.

The mirror 40 may be a multilayer reflective film. The multilayer reflective film can be formed, for example, by mixing Nb₂O₅Layer and SiO₂The layers are alternately deposited and stacked. Nb₂O₅The layer has a refractive index n of 2.282. Nb₂O₅The thickness of the layer may be, for example, about 100 nm. SiO 2₂The layer has a refractive index n of 1.468. SiO 2₂The thickness of the layer may be, for example, about 200 nm. Mirror 40 is, for example, Nb with 31 layers₂O₅Layer and 30 layers of SiO₂Total of layers 61 layers. The thickness of the mirror 40 may be, for example, 9.1 μm.

The dielectric layer 51 may be made of, for example, SiO₂And forming an evaporation layer. SiO 2₂The deposited layer has a refractive index n of 1.468. SiO 2₂The thickness of the deposition layer may be, for example, about 1.0 μm.

The optical waveguide 11 may be made of Nb₂O₅And forming an evaporation layer. Nb₂O₅The deposited layer has a refractive index n of 2.282. Nb₂O₅The thickness of the deposition layer may be, for example, about 300 nm. The grating 15 and the grating 13 may be formed in the optical waveguide 11. The grating 15 has, for example, a duty cycle of 1:1 and a pitch of 640 nm. The grating 13 has, for example, a duty cycle of 1:1 and a pitch of 680 nm. The grating 15 and the grating 13 can be formed by patterning by photolithography. The size of the optical waveguide 11 in the Y direction may be, for example, 10 μm.

The partition wall 73 may be made of SiO₂And forming an evaporation layer. SiO 2₂The deposited layer has a refractive index n of 1.468. SiO 2₂The thickness of the deposition layer may be 1.0 μm, for example. The size of the partition wall 73 in the Y direction may be, for example, 50 μm.

In the optical waveguide layer 20, a part of the dielectric layer 51 can be removed by patterning based on photolithography, for example. The thickness of the optical waveguide layer 20 may be, for example, 2.0 μm. The size of the optical waveguide layer 20 in the Y direction may be, for example, 10 μm.

Next, the materials and dimensions of the components of the upper structure 100b will be described in detail.

The substrate 50b may be made of, for example, SiO₂And (4) layer formation. The dimensions of the substrate 50a in the X direction and the Y direction are, for example, 8mm and 20mm, respectively, and the thickness of the substrate 50a may be, for example, 0.7 mm.

The electrode 62b may be formed of, for example, an ITO sputtered layer. The thickness of the electrode 62b may be 50nm, for example.

The mirror 30 may be a multilayer reflective film. The multilayer reflective film can be formed by mixing Nb₂O₅Layer and SiO₂The layers are alternately deposited and stacked. Nb₂O₅The layer has a refractive index n of 2.282. Nb₂O₅The thickness of the layer may be, for example, about 100 nm. SiO 2₂The layer has a refractive index n of 1.468. SiO 2₂The thickness of the layer may be, for example, about 200 nm. Mirror 30 is for example Nb with 7 layers₂O₅Layer and 6 layers of SiO₂Total of layers 13 layers. The thickness of the mirror 30 may be, for example, 1.9 μm.

Next, detailed examples of the materials and dimensions of the elastic spacer 77 and the sealing member 79 will be described.

For the elastic spacer 77, for example, Micropearl EX-003 made by water-in-volume chemistry can be used. The dimension of the elastic spacer 77 in the Z direction is, for example, 3.0 μm in a state before the lower structure 100a and the upper structure 100b are bonded. The dimension of the elastic spacer 77 is larger than the sum of the thickness of the partition wall 73 and the thickness of the mirror 30. The thickness of the partition walls 73 may be 1 μm, for example, and the thickness of the mirror 30 may be 1.9 μm, for example.

For the dielectric member 21, for example, 5CB liquid crystal can be used.

For example, a triple-bond (ThreeBond) ultraviolet curable adhesive 3026E can be used as the sealing member 79. For example, the passing wavelength is 365nm and the energy density is 100mJ/cm²The sealing member 79 is cured by the ultraviolet irradiation of (3), whereby the lower structure 100a and the upper structure 100b can be bonded to each other. Thereby, the optical device 100 of the present embodiment can be obtained.

The substrates 50a and 50b may not be made of SiO₂And (4) forming. The substrates 50a and 50b may be inorganic substrates such as glass and sapphire, or resin substrates such as acrylic and polycarbonate, for example. These inorganic substrates and resin substrates are light-transmitting.

The transmittance of the mirror 30 that emits light is, for example, 99.9%, and the transmittance of the mirror 40 that does not emit light is, for example, 99.99%. This condition can be achieved by adjusting the number of layers of the multilayer reflective film. In the combination of 2 layers in the multilayer reflective film, for example, one layer has a refractive index of 2 or more, and the other layer has a refractive index of less than 2. If the difference of the 2 refractive indices is large, high reflectance can be obtained. The layer having a refractive index of 2 or more may be composed of, for example, SiN_x、AlN_x、TiO_x、ZrO_x、NbO_xAnd TaO_xAt least 1 selected from the group consisting of. The layer with a refractive index of less than 2 may be formed, for example, from SiO_xOr AlO_xAt least 1 selected from the group consisting of.

The refractive index of the dielectric layer 51 is, for example, less than 2, and the refractive index of the optical waveguide 11 is, for example, 2 or more. If the difference of the 2 refractive indices is large, evanescent light that permeates from the optical waveguide 11 to the dielectric layer 51 can be reduced.

Next, the results of measuring the intervals at the a to i sites and the α to δ sites shown in fig. 9 will be described. The interval is investigated by phase difference (retardation) measurements. 75 optical waveguides 10 were used in this measurement. a. The b and c portions or the g, h and i portions are 3 portions of the end partition among the plurality of partitions 73. d. The e and f parts are 3 parts of the central partition among the plurality of partitions 73. The α to δ portions are 4 corner portions of the region surrounded by the seal member 79.

The interval at the a to i sites is the interval of the partition wall 73 from the mirror 30 in the Z direction, and the theoretical value of the interval is 0 nm. The interval at the α to δ portions is the interval between the dielectric layer 51 and the electrode 62b in the Z direction, and the theoretical value of the interval is 2.9 μm.

Table 1 shows the intervals at the a to i site and the α to δ site in the case where the elastic spacer 77 is not present.

[ Table 1]

In the absence of the elastic spacer 77, the average value of the intervals at the a to i sites was 0.146nm, and the standard deviation thereof was 0.128 nm. The average value of the intervals at the α to δ sites was 3.10 μm, and the standard deviation thereof was 0.154 μm. Therefore, the average value of the intervals greatly deviates from the above theoretical value, the dispersion of the intervals is large, and the intervals are not uniform.

[ Table 2]

Location	Gap (mum)	Location	Gap (mum)
				a	0.003	α	2.94
b	0.007	β	2.94
				c	0.005	γ	2.94
d	0.004	δ	2.94
				e	0.009	Mean value of	2.94
f	0.007	Standard deviation of	0.000
				g	0.003
h	0.006
				i	0.006
Mean value of	0.006
				Standard deviation of	0.002

Table 2 shows the intervals at the a to i site and the α to δ site in the case where the elastic spacer 77 is present. In the case where the elastic spacer 77 is present, the average value of the intervals at the a to i sites is 0.006nm, and the standard deviation thereof is 0.002 nm. The average value of the intervals at the α to δ sites was 2.94 μm, and the standard deviation thereof was 0.000 μm. Therefore, the average value of the intervals is close to the above theoretical value, the dispersion of the intervals is sufficiently small, and the intervals are uniform. That is, in the optical device 100 of the present embodiment, the uniformity of the interval between the substrates 50a and 50b can be greatly improved by the elastic spacer 77.

In the present embodiment, as shown in fig. 12A and 12B, a part of the upper structure 100B is cut and removed. In the example shown in fig. 12A and 12B, the XY-direction dimension of the upper structure 100B is smaller than the XY-direction dimension of the lower structure 100 a. In this case, the optical device may be manufactured by providing the elastic spacer 77 only in the region surrounded by the sealing member 79 and the periphery thereof shown in fig. 9, and bonding the lower structure 100a and the upper structure 100B shown in fig. 12A and 12B via the elastic spacer 77. The inventors of the present invention investigated that, in this case, the average value of the intervals at the a to i sites was 0.01nm, and the standard deviation thereof was 0.004 nm. The average value of the intervals at the α to δ sites was 2.94 μm, and the standard deviation thereof was 0.007 μm. In this case, the uniformity of the gap between the substrates 50a and 50b can be significantly improved. In contrast, in the optical device 100 of the present embodiment, as described above, the average value of the intervals at the a to i sites is 0.006nm, and the standard deviation thereof is 0.002 nm. The average value of the intervals at the α to δ sites was 2.94 μm, and the standard deviation thereof was 0.000 μm. Thus, by using the technique of the present invention, the uniformity of the interval between the substrates 50a and 50b can be further improved.

In the optical device 100 of the present embodiment, the mirror 30 of the upper structure 100b is not formed in the region where the elastic spacer 77 is formed. With this configuration, the Z-direction interval can be increased in the region where the elastic spacer 77 and the seal member 79 are formed. This prevents the liquid sealing member 79 before curing from spreading more than necessary. In addition, when the lower structure 100a and the upper structure 100b are bonded, if large particles are interposed between the lower structure 100a and the upper structure 100b, the gap after bonding may become uneven. In this case, in the present embodiment, the Z-direction interval of the peripheral portion where the fine particles are likely to be mixed is particularly large, and therefore the interval after bonding can be made uniform.

In the region where the elastic spacer 77 is formed, at least one of the mirror 30 and the mirror 40 may not be formed. In the above example, the mirror 30 is not formed. Conversely, the mirror 40 may not be formed. Alternatively, both the mirrors 30 and 40 may not be formed.

Next, a modification of the optical device 100 will be described. Fig. 13 is a sectional view schematically showing the structure of an optical device 100M according to a modification. The cross-section of the light device 100M shown in fig. 13 corresponds to the cross-section of line C-C shown in fig. 9. The upper diagram of fig. 13 shows a state before the lower structure 101a and the upper structure 101b are bonded. The lower diagram of fig. 13 shows a state in which the lower structure 101a and the upper structure 101b are bonded. In the above-described embodiment, the mirror 30 is not formed in the region where the elastic spacer 77 is formed in the upper structure 100 b. In contrast, in the present modification, the mirror 31 is also formed in the region where the elastic spacer 77 is formed. In the present modification, the interference between the adjacent waveguides 10, that is, the crosstalk can be significantly reduced.

Next, the results of measuring the light emitted from the optical device 100 of the present embodiment will be described.

Fig. 14 is a diagram schematically showing light emission from the optical device 100. In the example shown in fig. 14, the light emitted from the optical device 100 is measured by a photodetector, not shown, fixed in a direction in which the emission angle θ is 60 °. In this measurement, 589nm laser light is input to each optical waveguide 11 via the grating 13. It is known that in the case where the elastic spacers 77 are present, the intensity of the light measured is as high as about 100 times to about 1000 times as compared with the case where the elastic spacers 77 are not present. That is, in the optical device 100 of the present embodiment, the accuracy of the intensity and the emission angle of the emitted light can be greatly improved by the elastic spacer 77.

< production method >

An example of the method for manufacturing the optical device 100 will be described below.

Fig. 15 is a flowchart showing an example of a manufacturing process of the optical device 100. The manufacturing method of the optical device 100 of this example includes the following steps S101 to S106.

In step S101, a substrate 50a having a 1 st surface 50as and a substrate 50b having a 2 nd surface 50bs are prepared. In step S102, a plurality of partition walls 73 are formed on the 1 st surface 50 as. In step S103, elastic spacers 77 are formed on the 1 st surface 50as or the 2 nd surface 50bs and at locations located around the plurality of partition walls 73 in the finished state. In step S104, the sealing member 79 is applied to the 1 st surface 50as or the 2 nd surface 50bs and a portion which surrounds the plurality of partition walls 73 in the completed state and in which the elastic spacer 77 is not present. In step S105, the sealing member 79 is cured while the sealing member 79 is in close contact with the 1 st surface 50as and the 2 nd surface 50bs, whereby the substrate 50a and the substrate 50b are bonded to each other. In step S106, a part of the substrate 50a or 50b on which the elastic spacer 77 is not provided is cut and removed, and a part of the elastic spacer 77 is exposed.

A step of disposing the plurality of dielectric members 21 between the plurality of partition walls 73 may be included later than step S102. When the dielectric member 21 contains a liquid crystal material, a step of injecting the plurality of dielectric members 21 between the plurality of partition walls 73 may be included later than step S105.

By the above method, the optical device 100 can be manufactured.

< application example >

Fig. 16 is a diagram showing a configuration example of an optical scanning apparatus 100 in which elements such as the beam splitter 90, the waveguide array 10A, the phase shifter array 80A, and the light source 130 are integrated on a circuit substrate (for example, a chip). The light source 130 may be a light emitting element such as a semiconductor laser. The light source 130 in this example emits light of a single wavelength in free space at a wavelength λ. The optical splitter 90 branches light from the light source 130 and guides the light to the waveguides of the plurality of phase shifters. In the example shown in fig. 11, an electrode 62A and a plurality of electrodes 62B are provided on the chip. For the waveguide array 10A, a control signal is supplied from the electrode 62A. For a plurality of phase shifters 80 in the phase shifter array 80A, control signals are transmitted from a plurality of electrodes 62B, respectively. The electrode 62A and the plurality of electrodes 62B can be connected to a control circuit, not shown, that generates the control signal. The control circuit may be provided on the chip shown in fig. 11, or may be provided on another chip of the optical scanning apparatus 100.

As shown in fig. 16, by integrating all the components on a chip, a wide range of light scanning can be achieved with a small device. For example, all the components shown in fig. 11 can be integrated on a chip of about 2mm × 1 mm.

Fig. 17 is a schematic diagram showing a state where two-dimensional scanning is performed by irradiating a laser beam such as a laser beam from the optical scanning apparatus 100 to a distant place. The two-dimensional scanning is performed by moving the beam spot 310 in the horizontal and vertical directions. For example, a two-dimensional distance measurement image can be acquired by combining with a known TOF (Time Of Flight) method. The TOF method is a method of calculating the time of flight of light and determining the distance by irradiating laser light and observing reflected light from an object.

Fig. 18 is a block diagram showing a configuration example of the LiDAR system 300 as an example of a light detection system capable of generating such a distance measurement image. The LiDAR system 300 is equipped with an optical scanning device 100, a light detector 400, signal processing circuitry 600, and control circuitry 500. The photodetector 400 detects light emitted from the optical scanning apparatus 100 and reflected from the object. The light detector 400 may be, for example, an image sensor having sensitivity to the wavelength λ of light emitted from the optical scanning apparatus 100, or a light detector including a light receiving element such as a photodiode. The photodetector 400 outputs an electrical signal corresponding to the amount of received light. The signal processing circuit 600 calculates the distance to the object based on the electric signal output from the photodetector 400, and generates distance distribution data. The distance distribution data is data representing a two-dimensional distribution of distances (i.e., a range image). The control circuit 500 is a processor that controls the optical scanning apparatus 100, the photodetector 400, and the signal processing circuit 600. The control circuit 500 controls the timing of irradiation of the light beam from the optical scanning apparatus 100 and the timing of exposure and signal reading of the photodetector 400, and instructs the signal processing circuit 600 to generate a ranging image.

In the two-dimensional scanning, the frame rate for obtaining the range-finding image may be selected from, for example, 60fps, 50fps, 30fps, 25fps, 24fps, and the like, which are generally used in moving images. Further, if the application to the in-vehicle system is considered, the frequency of acquiring the range-finding image increases as the frame rate increases, and the obstacle can be detected with higher accuracy. For example, when the vehicle is traveling at 60km/h, images can be acquired at a frame rate of 60fps every time the vehicle moves by about 28 cm. At a frame rate of 120fps, images can be acquired each time the cart moves about 14 cm. At a frame rate of 180fps, images can be acquired each time the cart moves about 9.3 cm.

The time required to obtain a range image depends on the speed at which the beam is scanned. For example, in order to obtain an image with a resolution of 100 × 100 dots at 60fps, it is necessary to perform beam scanning at 1.67 μ s or less per 1 dot. In this case, the control circuit 500 controls the emission of the light beam by the optical scanning device 100 and the accumulation and readout of the signal by the photodetector 400 at an operation speed of 600 kHz.

< application example to light receiving apparatus >

The light scanning apparatus in the above-described embodiments of the present invention can also be used as a light receiving apparatus in substantially the same configuration. The light receiving device is provided with the same waveguide array 10A as the light scanning device, and a 1 st adjusting element that adjusts the direction of receivable light. Each 1 st mirror 30 of the waveguide array 10A transmits light incident from the 3 rd direction to the opposite side of the 1 st reflecting surface. Each optical waveguide layer 20 of the waveguide array 10A propagates the light transmitted through the 1 st mirror 30 in the 2 nd direction. The 1 st adjusting element can change the direction of receivable light by changing at least one of the refractive index and thickness of the optical waveguide layer 20 and the wavelength of light in each waveguide element 10. Further, in the case where the light receiving device includes the plurality of phase shifters 80, or 80a and 80b, which are the same as the light scanning device, and the 2 nd adjusting element that changes the difference in phase of the light output from the plurality of waveguide elements 10 through the plurality of phase shifters 80, or 80a and 80b, respectively, the direction of the receivable light can be changed two-dimensionally.

For example, a light receiving apparatus in which the light source 130 in the light scanning apparatus 100 shown in fig. 16 is replaced with a receiving circuit can be configured. If light of wavelength λ is incident on the waveguide array 10A, the light is transmitted to the optical splitter 90 via the phase shifter array 80A, and finally concentrated to one location to be transmitted to the receiving circuit. The intensity of the light concentrated at the one portion can be said to represent the light receiving deviceThe sensitivity of (2). The sensitivity of the light receiving device can be adjusted by adjusting elements assembled to the waveguide array and the phase shifter array 80A, respectively. In the light receiving device, for example, in fig. 4, the directions of the wave number vectors (thick arrows in the figure) become opposite. The incident light has a light component in the direction in which the waveguide elements 10 extend (X direction in the drawing) and a light component in the direction in which the waveguide elements 10 are arranged (Y direction in the drawing). The sensitivity of the light component in the X direction can be adjusted by the adjustment element assembled to the waveguide array 10A. On the other hand, the sensitivity of the light component in the alignment direction of the waveguide element 10 can be adjusted by the adjusting element assembled to the phase shifter array 80A. According to the phase difference of the light when the sensitivity of the light receiving device becomes maximumRefractive index n of optical waveguide layer 20_wAnd thickness d, theta and alpha shown in FIG. 4₀. Therefore, the incident direction of light can be determined.

From the above, the configuration and operation of the optical device 100 of the present embodiment as an optical scanning device or an optical receiving device are summarized as follows with reference to the examples shown in fig. 12A and 12B.

In the optical device 100 of the present embodiment, the plurality of dielectric members 21 include a liquid crystal material or an electro-optical material. The plurality of dielectric members 21 are sandwiched between the pair of electrodes 62a and 62b for applying a voltage. That is, the plurality of optical waveguides 10 have a structure capable of adjusting the refractive index of the plurality of dielectric members 21.

When the optical apparatus 100 of the present embodiment is used as an optical scanning apparatus, the direction of light emitted from the plurality of optical waveguides 10 through the substrate 50a or the substrate 50b is changed by adjusting the refractive index of the plurality of dielectric members 21. More specifically, the component in the X direction of the wave number vector of the light changes.

When the optical device 100 of the present embodiment is used as a light receiving device, the incident direction of light taken into the plurality of optical waveguides 10 via the substrate 50a or the substrate 50b is changed by adjusting the refractive index of the plurality of dielectric members 21. More specifically, the component in the X direction of the wave number vector of the light changes.

The optical device 100 of the present embodiment may further include a plurality of phase shifters 80 connected to the plurality of optical waveguides 10 directly or via another waveguide. When the number of optical waveguides 10 is 1, the number of phase shifters 80 is also 1.

When the optical device 100 of the present embodiment is used as an optical scanning device, the direction of light emitted from the plurality of optical waveguides 10 via the substrate 50a or 50b is changed by changing the difference in phase of light passing through the plurality of phase shifters 80. More specifically, the component in the Y direction of the wave number vector of the light changes.

When the optical device 100 of the present embodiment is used as a light receiving device, the incident direction of light taken into the plurality of optical waveguides 10 via the substrate 50a or 50b is changed by changing the phase difference of light passing through the plurality of phase shifters 80. More specifically, the component in the Y direction of the wave number vector of the light changes.

The above embodiments may be combined as appropriate.

Industrial applicability

The optical scanning device and the optical receiving device according to the embodiments of the present invention can be used for applications such as a laser radar system mounted on a vehicle such as an automobile, a UAV, or an AGV.

Description of the reference symbols

10 waveguide element and optical waveguide

11 optical waveguide

10A waveguide array

13 grating

15 grating

20 optical waveguide layer

21 dielectric member

30 st mirror

40 nd mirror

50a, 50b substrate

51 dielectric layer

62A, 62B, 62A, 62B electrode

73 multiple partition walls

80 phase shifter

80A phase shifter array

90 optical splitter

100. 100A optical scanning device

110 waveguide array driving circuit

130 light source

210 phase shifter array driving circuit

310 beam spot

400 photo detector

500 control circuit

600 signal processing circuit.