Transceiver

Abstract

To provide a transceiver in which degradation of quality of a signal can be suppressed.SOLUTION: A transceiver includes: a housing; a sending unit arranged in the housing, the sending unit sending an electromagnetic wave; a reception unit arranged in the housing, the reception unit receiving an electromagnetic wave; a transmission unit 50 covering an opening unit of the housing; a diffraction grating 60 formed in the transmission unit 50; and a heat generator 70 for heating the transmission unit 50. The heat generator 70 is arranged in a surface of the transmission unit 50 and is shaped to diffract an electromagnetic wave sent from the sending unit 20. At least a part of the diffraction grating is formed of the heat generator.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present disclosure relates to a transmitting / receiving device. [Background technology]

[0002] An optical transmitter / receiver used in LiDAR (Light Detection And Ranging) for detecting objects around an automobile includes a housing with an opening, a light source and a light receiving element disposed inside the housing, a diffraction grating for diffracting the output light of the light source, and an optical window for covering the opening of the housing. The light is scanned within a detection range, for example, by combining wavelength control of the output light with a diffraction function. The light is also scanned by changing the angle of incidence of the output light to the diffraction grating, for example, by a rotating element (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-28594 Summary of the Invention [Problem to be solved by the invention]

[0004] If the diffraction grating is disposed in front of the optical window, the optical window must be made large depending on the distance between the diffraction grating and the optical window and the desired detection range, which may result in an increase in the size of the optical transmitter / receiver.

[0005] In response to this, it is conceivable to reduce the distance between the diffraction grating and the optical window by arranging a diffraction grating on the optical window, thereby suppressing the increase in size of the optical window and the optical transmitting / receiving device. However, the optical window is often composed of multiple layers having various functions. For example, since there is a risk of the performance being reduced if snow, water droplets, etc. adhere to the optical window, it is conceivable to arrange a layer on the optical window on which a heating element made of a conductive material is formed, and to pass an electric current through the heating element to remove snow, etc., that adheres to the optical window. Furthermore, if the number of layers of the optical window is increased in order to arrange a diffraction grating on the optical window, there is a risk of the signal quality being reduced. This is also true when transmitting and receiving electromagnetic waves other than light.

[0006] In view of the above, an object of the present disclosure is to provide a transmitting / receiving device capable of suppressing degradation of signal quality. [Means for solving the problem]

[0007] In order to achieve the above object, according to one aspect of the present disclosure, a transceiver device comprises a housing (10), a transmitting unit (20) disposed inside the housing and transmitting electromagnetic waves, a receiving unit (20) disposed inside the housing and receiving electromagnetic waves, a transparent unit (50) covering an opening of the housing, a diffraction grating (60) formed in the transparent unit, and a heating element (70) for heating the transparent unit, the heating element being disposed on the surface of the transparent unit and shaped to diffract the electromagnetic waves transmitted by the transmitting unit, and at least a portion of the diffraction grating being composed of the heating element.

[0008] According to this, since at least a part of the diffraction grating is formed by a heating element, an increase in the number of layers in the transmission section due to the arrangement of the diffraction grating can be suppressed, and a deterioration in signal quality can be suppressed.

[0009] The reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and specific components described in the embodiments described below. [Brief description of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view of a transmitting / receiving device according to a first embodiment. [Diagram 2] 1 is a cross-sectional view of a transmitting / receiving device according to a first embodiment. [Diagram 3] This is a top view of a Photonic Integrated Circuit (PIC). [Figure 4] FIG. 4 is a diagram showing a change in the wavelength of emitted light. [Diagram 5] FIG. 2 is a diagram showing a configuration of a lens unit. [Figure 6] FIG. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII of FIG. [Figure 8] 11A and 11B are diagrams for explaining a deflection angle of emitted light. [Figure 9A] 5A to 5C are cross-sectional views showing a method for manufacturing a diffraction grating. [Figure 9B] 9B is a cross-sectional view showing the method of manufacturing the diffraction grating subsequent to FIG. 9A. [Figure 10] FIG. 11 is a top view of an optical window in the second embodiment. [Figure 11] FIG. 13 is a top view of an optical window in the third embodiment. [Figure 12] FIG. 13 is a top view of an optical window in the third embodiment. [Figure 13] FIG. 13 is a top view of an optical window in the third embodiment. [Figure 14] FIG. 13 is a top view of an optical window in the fourth embodiment. [Figure 15] FIG. 13 is a top view of an optical window in the fifth embodiment. [Figure 16] FIG. 13 is a diagram illustrating a configuration of a transmission unit in another embodiment. [Figure 17] FIG. 13 is a diagram illustrating a configuration of a transmission unit in another embodiment. [Figure 18] FIG. 13 is a diagram illustrating a configuration of a transmission unit in another embodiment. [Figure 19] FIG. 13 is a top view of an optical window in another embodiment. [Figure 20] FIG. 13 is a top view of an optical window in another embodiment. [Figure 21] FIG. 13 is a top view of a diffraction grating according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other will be denoted by the same reference numerals.

[0012] (First embodiment) A first embodiment will be described. In this embodiment, a case where the transceiver is used in a LiDAR of the FMCW (Frequency Modulated Continuous Wave) type will be described, but the transceiver may be used in a LiDAR of the TOF (Time of Flight) type. As shown in Figs. 1 and 2, the transceiver includes a housing 10, a PIC 20, a lens unit 30, a deflector 40, a transmission unit 50, a diffraction grating 60, and a diffraction grating 60. Note that the PIC 20 and the lens unit 30 are not shown in Fig. 2.

[0013] The housing 10 is made of a material that does not transmit light. A space is formed inside the housing 10, and the PIC 20, the lens unit 30, and the deflector 40 are arranged in this internal space.

[0014] 3, the PIC 20 includes a light source 21 that transmits an optical signal, and a light receiving element 22 that receives the optical signal. Inside the PIC 20, a coaxial optical system is configured in which the light source 21 and the light receiving element 22 are integrated. The PIC 20 corresponds to a transmitting unit and a receiving unit.

[0015] The PIC20 of this embodiment includes four light sources 21 that emit light of different wavelengths. The four light sources 21 are referred to as light sources 211, 212, 213, and 214. The light sources 211 to 214 include waveguides (not shown) arranged in parallel so as to be exposed at an end face of the PIC20, and the light sources 211 to 214 emit light from the end face of the PIC20.

[0016] The wavelengths of the light emitted from the light sources 211-214 are λ1, λ2, λ3, and λ4, respectively. The wavelengths λ1-λ4 are, for example, wavelengths included in the O-band or C-band, but the wavelengths λ1-λ4 may be wavelengths included in other wavelength bands. The light sources 211-214 are configured to change the wavelengths λ1-λ4 over time, and the wavelengths λ1-λ4 change within bandwidths of Δλ1, Δλ2, Δλ3, and Δλ4, respectively.

[0017] Specifically, as shown in Fig. 4, the light sources 211 and 212 change the wavelengths λ1 and λ2 into a triangular waveform for distance measurement using the FMCW method. Then, at a predetermined time t1, the light sources 211 and 212 change the wavelengths λ1 and λ2 for scanning the emitted light in the Y direction, which will be described later. Here, the wavelengths λ1 and λ2 are longer after time t1 than before. Similarly, the light sources 213 and 214 change the wavelengths λ3 and λ4 for distance measurement using the FMCW method and for scanning the emitted light. These changes are performed in the bandwidths of Δλ1, Δλ2, Δλ3, and Δλ4.

[0018] The PIC 20 includes four light receiving elements 22, and the four light receiving elements 22 are configured to receive optical signals of wavelengths λ1 to λ4 that change in the bandwidths Δλ1, Δλ2, Δλ3, and Δλ4, respectively.

[0019] The lens unit 30 expands and collimates the light emitted from the light source 21. The lens unit 30 is configured by combining two lenses. Specifically, as shown in FIG. 5, the lens unit 30 includes a support 31, a first lens 32, and a second lens 33. The support 31 is a cylindrical member with both ends open, and the first lens 32 and the second lens 33 are disposed inside the support 31. The lens unit 30 is configured such that light incident from an opening on one end side of the support 31 passes through the first lens 32 and the second lens 33 in this order and is emitted from an opening on the other end side.

[0020] The deflector 40 changes the direction of the light emitted from the light source 21 and scans the light emitted to the outside of the housing 10. As shown in FIG. 1, the deflector 40 is composed of a polygonal prism-shaped member, and the surface is a mirror that reflects light. The deflector 40 rotates around the central axis, and the light emitted from the light source 21 is reflected by the surface of the rotating deflector 40, thereby changing the direction of the light emitted to the outside of the housing 10. Note that, although the deflector 40 is shaped like a hexagonal prism in FIG. 1, it may be shaped like another polygonal prism. For example, the deflector 40 may be shaped like a pentagonal prism or a heptagonal prism.

[0021] An opening is formed on the upper surface of the housing 10, and the transmission section 50 is arranged to cover this opening. The transmission section 50 includes a plate-shaped optical window 51 made of a material that transmits optical signals, such as glass (SiO2), and the opening of the housing 10 is covered by the optical window 51. Two directions parallel to the upper surface of the optical window 51 and perpendicular to each other are defined as the X direction and the Y direction, respectively, and a direction perpendicular to the X direction and the Y direction is defined as the Z direction. As shown in FIG. 6, a diffraction grating 60 is formed on the upper surface of the optical window 51. Note that the optical window 51 may have a multilayer structure in which a functional film (not shown) is laminated on either or both of the upper and lower surfaces.

[0022] The diffraction grating 60 is for changing the direction of light emitted to the outside of the housing 10. As shown in FIG. 7, the diffraction grating 60 is a blazed diffraction grating having a sawtooth cross section. By forming the diffraction grating 60 as a blazed diffraction grating, it is possible to suppress the occurrence of interference fringes and reduce light loss. The diffraction grating 60 is formed by processing the upper surface of the transmission section 50 into a sawtooth wave shape by a semiconductor process. A part of the diffraction grating 60 is composed of a heating element 70.

[0023] The heating element 70 is for heating the transmission portion 50 to remove snow and the like adhering to the transmission portion 50, and is made of a conductive metal such as aluminum. The heating element 70 is integrally formed with the diffraction grating 60, and a part of the diffraction grating 60 is formed by the heating element 70. Specifically, the diffraction grating 60 has a valley part in a sawtooth cross section removed, and the heating element 70 is embedded in the removed part, so that the diffraction grating 60 and the heating element 70 form a sawtooth cross section. With this configuration, the heating element 70 is shaped to diffract the output light of the light source 21. Wiring (not shown) connected to the heating element 70 is formed on the outer periphery of the optical window 51, and by passing a current through the heating element 70 through the wiring, the heating element 70 generates heat and melts and removes the snow adhering to the optical window 51. In addition, when the optical window 51 has a multi-layer structure, a portion of the diffraction grating 60 is formed by the heating element 70, and the diffraction grating 60 and the heating element 70 are formed in the same layer among the multiple layers that make up the optical window 51.

[0024] 6, the heating elements 70 are arranged in stripes parallel to the X direction on the surface of the optical window 51. The heating elements 70 are arranged at a predetermined pitch that functions as a diffraction grating for the output light of the light source 21. Note that only a portion of the heating elements 70 may be arranged in stripes at this predetermined pitch.

[0025] As shown in Fig. 8, the pitch of the diffraction grating 60 and the heating element 70 is d, the angle of incidence of light to the diffraction grating 60 and the heating element 70 is α, and the angle of emergence is β. Furthermore, the refractive index of the diffraction grating 60 and the heating element 70 is n. If the wavelength of the light incident on the diffraction grating 60 and the heating element 70 is λ, then dsinα+dsinβ=λ / n. Rearranging this, β=arcsin(λ / dn-sinα).

[0026] For example, the pitch d is set to 700 nm, the refractive index n is set to 1.55, and the wavelength λ is changed with a central wavelength of 1550 nm and a bandwidth of 200 nm. If the angle of incidence α is 45 deg and the deflection angle Δβ of the output angle β is desired to be 15.45 deg, the pitch d is set so that λ / dn-sinα is 0.63 to 0.81. For example, the pitch d is set so that λ / dn-sinα is greater than 0.6, that is, d<λ / n(0.6+sinα).

[0027] In this embodiment, the pitch d is set so as to obtain the desired deflection angle Δβ for the wavelengths λ1 to λ4 and the bandwidths Δλ1 to Δλ4.

[0028] The diffraction grating 60 and the heating element 70 are manufactured, for example, as follows. First, a plate-shaped optical window 51 made of SiO2 is prepared. Then, as shown in FIG. 9A, stripe-shaped recesses parallel to the X direction are formed on the upper surface of the optical window 51 by etching. Then, as shown in FIG. 9B, an aluminum film 80 is vapor-deposited in the recesses formed in the step shown in FIG. 9A. Next, the optical window 51 and a portion of the aluminum film 80 are removed by etching to form the diffraction grating 60 and the heating element 70 in the shape shown in FIG. 7.

[0029] The operation of the transmitting and receiving device will be described. When the light source 21 emits light, the emitted light is expanded and collimated by the lens unit 30, and then irradiated onto the deflector 40. The light irradiated onto the deflector 40 is reflected on the surface of the deflector 40, passes through the transmission section 50, and is emitted to the outside of the housing 10.

[0030] As the deflector 40 rotates around its axis as shown by the arrow A1 in Fig. 1, the light irradiated to the deflector 40 is emitted upward in the Z direction and scanned in the X direction as shown by the arrow A2. In addition, since the diffraction grating 60 is formed in stripes parallel to the X direction, the emission angle at the diffraction grating 60 changes as shown in Fig. 8 by the light source 21 changing the wavelength of the emitted light, and the emitted light to the outside of the housing 10 is scanned in the Y direction. In addition, by the light sources 211 to 214 changing the wavelengths λ1 to λ4 in different wavelength bands, the light of the wavelengths λ1 to λ4 is scanned in different regions as shown by the arrows A3 to A6 in Fig. 2, and the LiDAR can detect objects over a wide range.

[0031] When the emitted light is reflected by an object, the reflected light passes through the optical window 51 and enters the light receiving element 22. A reception signal is output from the light receiving element 22 according to the intensity of the incident light, and an ECU (Electronic Control Unit) (not shown) or the like performs object detection determination based on this reception signal.

[0032] As described above, in this embodiment, the heating element 70 is configured integrally with the diffraction grating 60, and a portion of the diffraction grating 60 is configured by the heating element 70, so that it is possible to arrange the diffraction grating 60 and the heating element 70 in the same layer of the optical window 51. This makes it possible to suppress degradation of signal quality due to an increase in the number of layers of the optical window 51.

[0033] Moreover, it is possible to prevent the optical window 51 from becoming larger than when the diffraction grating 60 is disposed inside the housing 10 away from the optical window 51. Moreover, it is possible to reduce the size of the transceiver device compared to when the diffraction grating 60 is disposed outside the housing 10 away from the optical window 51.

[0034] Second embodiment The second embodiment will be described. This embodiment is different from the first embodiment in that the configuration of the heating element 70 is changed, and other aspects are the same as those of the first embodiment, so only the differences from the first embodiment will be described.

[0035] 10, the heating element 70 includes a first heating element 71 and a second heating element 72. A direction parallel to the surface of the optical window 51 is defined as a first direction, and a direction parallel to the surface of the optical window 51 and inclined with respect to the first direction is defined as a second direction. The first heating element 71 is arranged in stripes parallel to the first direction, and the second heating element 72 is arranged in stripes parallel to the second direction.

[0036] In this embodiment, the first heating elements 71 are arranged in stripes parallel to the X direction, and have the same configuration as the heating elements 70 of the first embodiment. The second heating elements 72 are arranged in stripes parallel to the Y direction.

[0037] The diffraction grating 60 and the heating element 70 of this embodiment are manufactured, for example, as follows. First, a plate-shaped optical window 51 made of SiO2 is prepared. Then, stripe-shaped recesses parallel to the X direction and stripe-shaped recesses parallel to the Y direction are formed on the upper surface of the optical window 51 by etching. Next, an aluminum film is vapor-deposited into these recesses. Next, the optical window 51 and a part of the aluminum film are removed by etching so that the cross section perpendicular to the X direction has a sawtooth wave shape, thereby forming the diffraction grating 60 and the heating element 70 having the shape shown in FIG. 10.

[0038] This embodiment has the same configuration and operation as the first embodiment, and therefore can obtain the same effects as the first embodiment.

[0039] Furthermore, according to the above embodiment, the following effects can be obtained.

[0040] (1) The heating element 70 includes a first heating element 71 arranged in stripes parallel to a first direction, and a second heating element 72 arranged in stripes parallel to a second direction. This allows the second heating element 72 to ensure a current path and maintain heat generation performance even if the first heating element 71 is broken. Furthermore, by arranging the second heating element 72 in addition to the first heating element 71, the amount of heat generated by the heating element 70 can be increased.

[0041] Third embodiment The third embodiment will be described. This embodiment is the same as the second embodiment except that the pitch of the second heating elements 72 is changed from that of the second embodiment, and therefore only the differences from the second embodiment will be described.

[0042] In this embodiment, the pitch of the first heating elements 71 is constant, whereas the pitch of the second heating elements 72 varies depending on the location.

[0043] 11, the second heating element 72 includes a portion arranged at a pitch d1 and a portion arranged at a pitch d2 larger than the pitch d1. The portion arranged at the pitch d2 is sandwiched between the portions arranged at the pitch d1. This can reduce interference fringes compared to when the second heating elements 72 are arranged at equal intervals.

[0044] 12, the pitch of the second heating elements 72 at both ends of the optical window 51 in the X direction may be made smaller than the pitch at the center of the optical window 51 in the X direction. This makes it possible to maintain the heating performance while reducing the light loss at the center of the optical window 51 in the X direction and maintaining the object detection performance.

[0045] 13, the pitch of the second heating elements 72 at one end of the optical window 51 in the X direction may be smaller than the pitch at the center and the other end of the optical window 51 in the X direction. This makes it possible to maintain the heating performance while maintaining the object detection performance by reducing the light loss at the center and the other end of the optical window 51 in the X direction.

[0046] This embodiment has the same configuration and operation as the first and second embodiments, and therefore can obtain the same effects as the first and second embodiments.

[0047] Furthermore, according to the above embodiment, the following effects can be obtained.

[0048] (1) The pitch of the first heating elements 71 is constant, and the pitch of the second heating elements 72 varies depending on the location. This makes it possible to reduce interference fringes compared to a case in which the second heating elements 72 are arranged at equal intervals.

[0049] (Fourth embodiment) A fourth embodiment will be described. This embodiment is the same as the second embodiment except for the line width of the second heating element 72, and therefore only the differences from the second embodiment will be described.

[0050] 14, in this embodiment, the line width of the second heating element 72 is made larger than that of the first heating element 71. This increases the amount of heat generated in the second heating element 72, thereby improving the heat generation performance of the heating element 70.

[0051] This embodiment has the same configuration and operation as the first and second embodiments, and therefore can obtain the same effects as the first and second embodiments.

[0052] Fifth embodiment A fifth embodiment will be described. This embodiment is the same as the second embodiment except for the line width of the second heating element 72, and therefore only the differences from the second embodiment will be described.

[0053] In this embodiment, the line width of the first heating element 71 is constant, whereas the line width of the second heating element 72 varies depending on the location. Specifically, as shown in Fig. 15, the line width of the second heating element 72 at both ends in the X direction of the optical window 51 is made larger than the line width at the central part of the optical window 51 in the X direction. This makes it possible to reduce light loss at the central part of the optical window 51 in the X direction, thereby improving heat generation performance while maintaining object detection performance.

[0054] This embodiment has the same configuration and operation as the first and second embodiments, and therefore can obtain the same effects as the first and second embodiments.

[0055] Furthermore, according to the above embodiment, the following effects can be obtained.

[0056] (1) The line width of the first heating element 71 is constant, and the line width of the second heating element 72 varies depending on the location. This makes it possible to increase the amount of heat generated in the area with a large line width. Also, it is possible to reduce light loss in the area with a small line width.

[0057] (Other embodiments) The present disclosure is not limited to the above-described embodiments, and can be modified as appropriate. The above-described embodiments are not unrelated to each other, and can be combined as appropriate, except when the combination is clearly impossible. In the above-described embodiments, it goes without saying that the elements constituting the embodiments are not necessarily essential, except when they are specifically stated to be essential or when they are clearly considered to be essential in principle. In the above-described embodiments, when the numbers, values, amounts, ranges, etc. of the components of the embodiments are mentioned, they are not limited to the specific numbers, except when they are specifically stated to be essential or when they are clearly limited to a specific number in principle. In the above-described embodiments, when the shapes, positional relationships, etc. of the components are mentioned, they are not limited to the shapes, positional relationships, etc., except when they are specifically stated to be essential or when they are clearly limited to a specific shape, positional relationship, etc. in principle.

[0058] The transmitting section and the receiving section may have a different configuration from those of the above-mentioned embodiments. For example, as shown in FIG. 16, a microlens 23 may be arranged on the end face of the PIC 20, and the output light of the light source 21 may enter the lens unit 30 through the microlens 23. As shown in FIG. 17, a mirror 24 may be arranged to face the end face of the PIC 20 obliquely, and the emitted light of the light source 21 may enter the lens unit 30 after being reflected by the mirror 24. As shown in FIG. 18, the mirror 24 may be arranged inside the PIC 20. The PIC 20 may have only one light source 21, and the light source 21 may output a plurality of light beams with different wavelengths in a superimposed manner. The PIC 20 may have only one light source 21, and the light source 21 may output light of a single wavelength.

[0059] The light source 21 may not change the wavelength for scanning, but may only change the wavelength for distance measurement using the FMCW method.

[0060] The first lens 32 and the second lens 33 constituting the lens unit 30 may be bonded together. The lens unit 30 may include only one lens. The transmitting / receiving device may not include the lens unit 30, and the light emitted from the light source 21 may be directly irradiated onto the polarizer 40.

[0061] The deflector 40 may be composed of a liquid crystal polarizing element, a MEMS (Micro Electro Mechanical Systems) mirror, a mirror oscillating with a voice coil motor, or a focal plane array. When the deflector 40 is composed of a focal plane array, a plurality of light sources 21 emitting light of the same wavelength are arranged, and the light sources 21 emitting light are periodically switched to change the location where the light is incident on the focal plane array, thereby scanning the light emitted to the outside of the housing 10.

[0062] The transmitting / receiving device does not necessarily have to include the deflector 40. In other words, the emitted light may not be scanned in the X direction, but may only be scanned in the Y direction by changing the wavelength.

[0063] In the second embodiment, the first heating element 71 and the second heating element 72 are arranged with the X direction as the first direction and the Y direction perpendicular to the X direction as the second direction, but the second direction does not have to be perpendicular to the first direction. The conductors constituting the heating element 70 may extend in three or more directions. For example, as shown in FIG. 19, the heating element 70 may include a third heating element 73 in addition to the first heating element 71 and the second heating element 72, and the second heating element 72 and the third heating element 73 may be arranged in stripes parallel to the directions inclined in both the X direction and the Y direction. By extending the second heating element 72 in the directions inclined in both the X direction and the Y direction, interference fringes can be reduced.

[0064] In Fig. 10 and other figures, the second heating element 72 is formed in a continuous straight line from one end side to the other end side in the Y direction of the region in which the first heating element 71 is formed, but the second heating element 72 may be interrupted midway. For example, as shown in Fig. 20, the second heating element 72 may be formed in a broken line. This makes it possible to prevent disconnection and reduce light loss compared to when the second heating element 72 is formed in a continuous straight line.

[0065] The heating element 70 may constitute a VPH (Volume Phase Holographic) diffraction grating. For example, the heating element 70 may be constituted by an ITO (Indium Tin Oxide) film laminated over the entire upper surface of the optical window 51, and the diffraction grating 60 may be constituted by providing a refractive index distribution in the plane as shown in FIG. 21. In FIG. 21, the refractive index is represented by the density of dotted hatching. By making the diffraction grating 60 a VPH diffraction grating, it is possible to reduce optical loss. The entire diffraction grating 60 may be constituted by the heating element 70, for example, by making the diffraction grating 60 a VPH diffraction grating constituted by the heating element 70.

[0066] The transmitting / receiving device may be configured to transmit and receive electromagnetic waves other than optical signals. That is, the transmitting / receiving device may include a transmitting section that transmits electromagnetic waves, a receiving section that receives the electromagnetic waves, and a transmitting section that transmits the electromagnetic waves, and the heating element 70 may be shaped to diffract the electromagnetic waves transmitted by the transmitting section. [Explanation of symbols]

[0067] 10. Chassis 20 PIC 50 Transparent part 60 Diffraction Grating 70 Heating element

Claims

1. A transmitting / receiving device, A housing (10); A transmitter (20) arranged inside the housing and transmitting electromagnetic waves; A receiving unit (20) arranged inside the housing and receiving electromagnetic waves; A transparent portion (50) that covers the opening of the housing; A diffraction grating (60) formed in the transmission portion; A heating element (70) for heating the transmission portion, the heating element is disposed on a surface of the transmitting portion and has a shape that diffracts the electromagnetic wave transmitted by the transmitting portion, A transmitting / receiving device, wherein at least a portion of the diffraction grating is formed by the heating element.

2. The transmitting unit includes a light source (21) for transmitting an optical signal, The receiving unit includes a light receiving element (22) for receiving an optical signal, The transmission portion includes an optical window (51) through which an optical signal passes, The transmitting / receiving device according to claim 1 , wherein the heating element is shaped to diffract the optical signal transmitted by the light source.

3. The transmitting / receiving device according to claim 1 , wherein the heating elements are arranged in a striped pattern on the surface of the transmitting portion, and are arranged at a pitch that functions as a diffraction grating for the electromagnetic wave transmitted by the transmitting portion.

4. 4. The transmitting / receiving device according to claim 3, wherein the pitch of the heating element varies depending on the location.

5. 4. The transmitting / receiving device according to claim 3, wherein the line width of the heating element varies depending on the location.

6. A direction parallel to a surface of the transmission portion is defined as a first direction, a direction parallel to a surface of the transmission portion and inclined with respect to the first direction is defined as a second direction, A transmitting / receiving device as described in any one of claims 3 to 5, wherein the heating element includes a first heating element (71) arranged in a stripe pattern parallel to the first direction, and a second heating element (72) arranged in a stripe pattern parallel to the second direction.

7. The pitch of the first heating element is constant, The transmitting / receiving device according to claim 6 , wherein the pitch of the second heating element varies depending on the location.

8. The line width of the first heating element is constant, The transmitting / receiving device according to claim 6 , wherein the line width of the second heating element varies depending on the location.

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