Lens unit and measuring device

Abstract

In the present invention, the configuration of a lens unit is simplified. This lens unit comprises: a meta-lens including a substrate having an effective region on a surface and allowing the transmission of light, and a plurality of micro-structures disposed in the effective region; and a heater disposed on a surface of the meta-lens.

Description

Lens unit and measuring device

[0001] The technology disclosed in this specification relates to a lens unit and a measurement device.

[0002] With the advancement of autonomous driving (AD) systems and advanced driver assistance systems (ADAS), research and development of light detection and ranging (LiDAR) is underway as one of the measurement devices used to grasp the surrounding environment and estimate the vehicle's position while driving. LiDAR includes a transmitter (light projector) that projects laser light onto a measurement target and a receiver (light receiver) that receives the light reflected from the measurement target. LiDAR measures the distance to the measurement target based on the difference between the timing at which the light projector emits the laser light and the timing at which the light receiver receives the reflected light. The light projector includes a lens that is positioned on the optical path of light emitted by a light source (see Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2021-105613

[0004] In the above-mentioned measuring device, a lens unit equipped with a heater for warming the lens is sometimes used to reduce the occurrence of condensation on the lens. There is a demand for a simpler configuration for such a lens unit. The same problem applies to a lens unit provided in a light receiver that receives reflected light.

[0005] This specification discloses a technique that can solve the above-mentioned problems.

[0006] The technology disclosed in this specification can be realized, for example, in the following forms.

[0007] (1) The lens unit disclosed in this specification comprises a metalens having a substrate having an effective area on its surface and allowing light to pass through, and a plurality of microstructures arranged in the effective area, and a heater disposed on the surface of the metalens.

[0008] According to the above configuration, the configuration of the lens unit is simplified.

[0009] (2) In the lens unit described in (1) above, the metalens may have a flat surface on its surface, and the heater may be disposed on the flat surface.

[0010] Such a configuration makes it easier to manufacture the lens unit.

[0011] (3) In the lens unit described in (1) or (2) above, the surface of the substrate may have a first surface and a second surface opposite to the first surface, the first surface having the effective area and a first peripheral area different from the effective area, the second surface having a back area located back to back with the effective area and a second peripheral area different from the back area, and the heater may be arranged in at least one of the first peripheral area and the second peripheral area.

[0012] According to this configuration, a material that does not allow light to pass through can be used as the heater material, which widens the options for heater materials.

[0013] (4) The heater according to any one of (1) to (3) above may be a transparent heater that includes a transparent conductive film and allows light to pass through.

[0014] According to the above configuration, the options for heater placement are expanded.

[0015] (5) In the lens unit described in (4) above, the surface of the substrate may have a first surface and a second surface opposite to the first surface, the first surface having the effective area, the second surface having a back area located back to back with the effective area, and the heater may be disposed in the back area.

[0016] With this configuration, the portion that functions as a lens can be efficiently heated.

[0017] (6) In the lens unit described in (4) or (5) above, the metalens may include a cover layer that covers the microstructure, and the heater may be disposed on a surface of the cover layer.

[0018] This configuration provides a wider range of heater placement options, and also allows for efficient heating of the area of ​​the metalens that functions as a lens.

[0019] (7) The measuring device disclosed in this specification may include a lens unit according to any one of (1) to (6) above, and may also include a photodetector that receives light reflected by the object to be measured.

[0020] (8) The measuring device disclosed in this specification may include the lens unit according to any one of (1) to (6) above, and may also include a projector that emits light to the outside.

[0021] 4 is a cross-sectional view of the metalens of the second embodiment taken along line V-V in FIG. 4; a cross-sectional view of the metalens of the third embodiment; a block diagram showing a schematic configuration of the measurement device of the fourth embodiment; and a cross-sectional view of the metalens of the fourth embodiment.

[0022] First Embodiment A first embodiment will be described with reference to FIGS. 1 to 3. A measurement device 10 of this embodiment is a LiDAR that uses a surface-emitting laser as a light source 110. The measurement device 10 is mounted on, for example, a vehicle equipped with an AD (autonomous drive) or an ADAS (advanced driver assistance system). The measurement device 10 assists in detecting objects such as people and other vehicles while the vehicle is traveling, and provides various information to other devices and users that is useful for ensuring the safety of the driver of the vehicle and those around the vehicle, and for reducing damage to surrounding objects while the vehicle is being driven.

[0023] As shown in FIG. 1, the measuring device 10 includes a light projector 100, a light receiver 200, an information processing device 500, and a communication interface 600.

[0024] As shown in FIG. 1 , the light projector 100 includes a light source 110 , a light projection control device 120 , a current source 130 , and a light projection optical system 180 .

[0025] The light source 110 includes a semiconductor substrate and a plurality of light-emitting elements arranged on the semiconductor substrate, each of which emits laser light. The light-emitting elements may be vertical cavity surface emitting lasers (VCSELs).

[0026] The light-projection control device 120 is, for example, a microcomputer and includes a processor and a storage device. The processor is, for example, a central processing unit (CPU). The storage device includes, for example, a read-only memory (ROM) and a random access memory (RAM). The storage device stores various programs and data, and is used as a work area for executing various processes and as a data storage area. The current source 130 is, for example, a general current circuit including a capacitor, a resistor, and a switching element. The light-projection control device 120 outputs a drive signal to the current source 130. The current source 130 receives the drive signal, generates a drive current corresponding to the drive signal, and supplies the drive current to the light source 110. In addition, the light-projection control device 120 outputs a signal indicating the light emission timing of the light source 110.

[0027] The projection optical system 180 is an optical component disposed on the optical path of the laser light emitted from the light source 110. The projection optical system 180 may be a collimating lens that adjusts the laser light emitted from the light source 110 to become parallel light.

[0028] As shown in FIG. 1, the light receiver 200 includes a light receiving optical system 210 (an example of a lens unit), a light receiving section 250, and a TOF measurement device 260.

[0029] As shown in FIGS. 2 and 3 , the light receiving optical system 210 includes a metalens 220 and a heater 230.

[0030] The metalens 220 comprises a substrate 221 and a plurality of microstructures 222 arranged on the surface of the substrate 221.

[0031] Substrate 221 is a rectangular plate material that allows the transmission of laser light emitted from light source 110. The surface of substrate 221 includes a flat exit surface SO (the surface of a metalens, an example of a first surface) and a flat entrance surface SI (the surface of a metalens, an example of a second surface) that is disposed on the opposite side of exit surface SO. The central portion of exit surface SO is the effective area Ae, and the area surrounding effective area Ae is the first peripheral area Ap1. The area of ​​entrance surface SI that is back to back with effective area Ae is the back area Ab, and the area surrounding back area Ab is the second peripheral area Ap2. Materials for substrate 221 include, for example, glass, TiO ２ , SiO ２ , synthetic resin. In this embodiment, the substrate 221 is made of glass. The thickness of the substrate 221 may be, for example, 100 nm or more and 3 mm or less.

[0032] The microstructures 222 are minute protrusions protruding from the surface of the substrate 221. The microstructures 222 are arranged in a predetermined pattern in the effective area Ae. The arrangement pattern of the microstructures 222 and the shape and size of each microstructure 222 are designed according to the optical function required of the metalens 220. In this embodiment, the microstructures 222 are designed so that the metalens 220 functions as a condenser lens that condenses light. The metalens 220 may also have a polarizing filter function that passes only light vibrating in a specific direction. The shape of each microstructure 222 may be, for example, cylindrical or rectangular. The distance between adjacent microstructures 222 is set to be small compared to the wavelength of light incident on the metalens 220. In this embodiment, the distance between adjacent microstructures 222 is set to be small compared to the wavelength of the laser light emitted from the light source 110, i.e., the wavelength of infrared light. The material of the microstructures 222 is, for example, silicon (Si), glass, TiO ２ , SiO ２ In this embodiment, the material of the minute structure 222 is silicon with a refractive index of about 3.5. The height of the minute structure 222 from the light output surface SO may be about 500 nm.

[0033] The heater 230 may be a planar heater including two films 231 and 232 stacked on top of each other and a conductive pattern 233 disposed between the two films 231 and 232. The two films 231 and 232 may be made of synthetic resin. The conductive pattern 233 is formed from a conductive material and has a predetermined pattern. The conductive pattern 233 may be formed by etching a metal foil. The heater 230 may be attached to the substrate 221 by an adhesive layer 240. The heater 230 is disposed in the second peripheral region Ap2. In this embodiment, the heater 230 has an annular shape and surrounds the entire back region Ab. Lead wires (not shown) are electrically connected to both ends of the conductive pattern 233. When a voltage is applied between the two lead wires, the conductive pattern 233 generates heat, warming the metalens 220.

[0034] The light receiving unit 250 includes a light receiving element, which may be a photodiode. The light receiving unit 250 receives the reflected laser light Lre incident from the light receiving optical system 210, converts the reflected laser light Lre into a light receiving signal corresponding to the intensity and timing of receiving the reflected laser light Lre, and outputs the light receiving signal.

[0035] The TOF measurement device 260 includes, for example, a time measurement integrated circuit (IC) equipped with a time-to-digital converter (TDC) circuit. The TOF measurement device 260 is communicatively connected to the light-projection control device 120 and the light-receiving unit 250. The TOF measurement device 260 receives a timing signal indicating the light emission timing output from the light-projection control device 120 and a light-receiving signal output from the light-receiving unit 250. Based on these signals, the TOF measurement device 260 calculates the difference between the timing at which the output laser light Lout is emitted and the timing at which the reflected laser light Lre is received, i.e., the time of flight (TOF) of the laser light. The TOF measurement device 260 outputs a signal corresponding to the calculated TOF and the light-receiving signal received from the light-receiving unit 250.

[0036] The information processing device 500 has a processor. The processor may be, for example, a central processing unit (CPU), a microprocessing unit (MPU), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or a digital signal processor (DSP). The information processing device 500 is communicatively connected to the TOF measurement device 260. The information processing device 500 receives a signal corresponding to the TOF output by the TOF measurement device 260 and a light receiving signal, and generates various information based on these signals. The information may be, for example, a histogram used in time-correlated single photon counting, distances to each point on the measurement target W, or point cloud information. The information generated by the information processing device 500 is transmitted via a communication interface 600 to an external device 700 that uses the information.

[0037] The external device 700 may be, for example, a device that creates an environmental map using a point cloud, or may be a device that performs self-location estimation (SLAM: Simultaneous Localization and Mapping) using a scan matching algorithm such as NDT (Normal Distributions Transform) or ICP (Iterative Closest Point).

[0038] Next, the basic operation of the measurement device 10 will be described. The light-projection control device 120 pulse-controls the light source 110. That is, the light-projection control device 120 outputs a drive signal to the current source 130 so that the light-emitting element provided in the light source 110 intermittently outputs laser light at predetermined timings. The current source 130 generates a pulse current having a frequency and magnitude corresponding to the received drive signal and supplies it to the light source 110. The light source 110 outputs laser light having a frequency and intensity corresponding to the supplied drive current. In addition, the light-projection control device 120 outputs a signal indicating the light emission timing at which the light source 110 emitted the laser light to the TOF measurement device 260. The output laser light passes through the light-projection optical system 180 and is emitted to the outside of the projector 100.

[0039] The reflected laser light Lre, which is the output laser light Lout reflected by the measurement target W and returned, enters the light receiving optical system 210. The reflected laser light Lre enters the incident surface SI of the metalens 220 provided in the light receiving optical system 210, is collected, and exits from the exit surface SO. The exiting reflected laser light Lre enters the light receiving unit 250. The light receiving unit 250 outputs a light receiving signal corresponding to the intensity and light receiving timing of the reflected laser light Lre to the TOF measurement device 260.

[0040] As described above, the TOF measurement device 260 determines the time of flight (TOF) of the laser light based on the timing signal indicating the light emission timing output from the light projection control device 120 and the light reception signal output from the light receiving unit 250. The determined TOF is output to the information processing device 500 and is used to generate various information.

[0041] Generally, vehicles equipped with a measuring device are used in a variety of environments. For example, when a vehicle is used in a cold climate, the lens of the measuring device may become cold and condense, which may reduce the accuracy of sensing. In such cases, it is useful to reduce the occurrence of condensation on the lens by using a heater to warm the lens.

[0042] In conventional measuring devices, in order to meet the required optical performance, lens units combining multiple refractive lenses are generally used as the light projecting and receiving optical systems, which means that the heater configuration for heating all of the multiple lenses tends to be complicated.

[0043] In this embodiment, the light receiving optical system 210 includes a metalens 220, and a heater 230 is disposed on the incident surface SI of the metalens 220. The metalens 220 has a large number of microstructures 222 disposed on the surface of a substrate 221, and the desired optical performance can be achieved by appropriately designing the shapes and arrangement patterns of the microstructures 222. In other words, because the desired optical performance can be achieved with a small number of metalenses 220, the configuration of the heater 230 for heating the metalens 220 can be simplified, and the configuration of the light receiving optical system 210 is simplified.

[0044] When a refractive lens is used as the lens, the lens needs to have a certain thickness in order to form a convex or concave surface on the surface. In addition, as described above, when multiple refractive lenses are used in a lens unit, high output power is required from the heater in order to heat all of the multiple lenses. However, in the metalens 220, optical performance is achieved by a large number of microstructures 222, and the substrate 221 does not need to be very thick, so the substrate 221 can be made thinner. In addition, as described above, the desired optical performance can be achieved with a small number of metalenses 220. Therefore, even if the heater 230 has a relatively low output power, the metalens 220 can be efficiently heated, reducing the manufacturing and operating costs of the measurement device 10.

[0045] When a refractive lens is used as the lens, the surface of the lens is convex or concave, and therefore, advanced technology is required to arrange the heater on the convex or concave surface. In this embodiment, the substrate 221 is flat and has a flat incident surface SI, so that the heater 230 can be easily arranged on this incident surface SI.

[0046] In this embodiment, the heater 230 is disposed in the second peripheral region Ap2. That is, the heater 230 is located back to back with the effective region Ae, and is disposed so as to avoid the back region Ab, which needs to transmit light. This makes it possible to use a material that does not transmit light as the material for the heater 230, increasing the degree of freedom in material selection. Furthermore, the heater 230 surrounds the entire back region Ab. This allows the portion of the metalens 220 that functions as a lens to be heated efficiently.

[0047] As described above, the measurement apparatus 10 of this embodiment includes the light-receiving optical system 210. The light-receiving optical system 210 includes a metalens 220 and a heater 230. The metalens 220 includes a substrate 221 and a plurality of microstructures 222. The substrate 221 has an effective area Ae on the emission surface SO and allows light to pass through. The microstructures 222 are arranged in the effective area Ae. The heater 230 is arranged on the incidence surface SI of the substrate 221. This configuration simplifies the configuration of the light-receiving optical system 210.

[0048] The incident surface SI is a flat surface, and the heater 230 is disposed on this incident surface SI. With this configuration, the light receiving optical system 210 can be easily manufactured.

[0049] The surface of the substrate 221 has an incident surface SI and an exit surface SO. The exit surface SO has an effective area Ae and a first peripheral area Ap1 different from the effective area Ae, and the incident surface SI has a back area Ab located back to back with the effective area Ae and a second peripheral area Ap2 different from the back area Ab. The heater 230 is disposed in the second peripheral area Ap2. With this configuration, a material that does not allow light to pass through can be used as the material for the heater 230, expanding the options for materials for the heater 230.

[0050] Second Embodiment A second embodiment will be described with reference to Figures 4 and 5. A light receiving optical system 210A (an example of a lens unit) of this embodiment is provided in a light receiver of a measurement device, similar to the first embodiment. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0051] The light receiving optical system 210A of this embodiment includes a metalens 220 and a heater 230A. The configuration of the metalens 220 is similar to that of the first embodiment.

[0052] The heater 230A is a transparent heater and includes two films 231A and 232A stacked on top of each other. A transparent conductive film 233A and a pair of electrodes 234 are disposed between the two films 231A and 232A. The films 231A and 232A allow light to pass through. The films 231A and 232A may be made of synthetic resin. The transparent conductive film 233A is a thin film formed of a conductive material that allows light to pass through. The transparent conductive film 233A is made of, for example, indium tin oxide (ITO). The pair of electrodes 234 are electrically connected to the transparent conductive film 233A. The electrodes 234 are made of a conductive material, such as a metal. In this embodiment, the transparent conductive film 233A is disposed over the entire back surface region Ab and part of the second peripheral region Ap2, and the pair of electrodes 234, 234 is disposed in the second peripheral region Ap2. The heater 230A may be attached to the substrate 221 by an adhesive layer 240A that allows light to pass through. When a voltage is applied between the electrodes 234, 234, the transparent conductive film 233A generates heat, and the metalens 220 is warmed.

[0053] In this embodiment, as in the first embodiment, the light receiving optical system 210A includes a metalens 220, and the heater 230A is disposed on the incident surface SI of the substrate 221 included in the metalens 220. This simplifies the configuration of the light receiving optical system 210A.

[0054] Additionally, in this embodiment, heater 230A is a transparent heater that includes transparent conductive film 233A and allows light to pass through. With this configuration, heater 230A can be disposed in back surface region Ab, where light transmission is required, thereby expanding the options for disposing heater 230A. Additionally, by disposing heater 230A in back surface region Ab, the region of metalens 220 that functions as a lens can be efficiently heated.

[0055] Third Embodiment A third embodiment will be described with reference to Fig. 6. The light receiving optical system 210B of this embodiment is provided in the light receiver of the measurement device, similar to the first embodiment. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0056] The light receiving optical system 210B (an example of a lens unit) of this embodiment includes a metalens 220B and a heater 230A.

[0057] The metalens 220B includes a substrate 221, a plurality of microstructures 222 arranged on the surface of the substrate 221, and a cover layer 223. The configurations of the substrate 221 and the microstructures 222 are the same as those in the first embodiment. The cover layer 223 is arranged on the emission surface SO of the substrate 221 and covers the microstructures 222. The material of the cover layer 223 may be a low-refractive-index resin with a refractive index of 1.1 to 1.3. The thickness of the cover layer 223 may be sufficient to cover the entire microstructures 222, and is, for example, approximately 1-2 μm. The surface of the cover layer 223 includes an outer surface SC on the opposite side to the emission surface SO. The outer surface SC is flat and parallel to the emission surface SO. The area of ​​the outer surface SC that covers the effective area Ae is a cover area Ac, and the area surrounding the cover area Ac is a third peripheral area Ap3.

[0058] The heater 230A is a transparent heater having a configuration similar to that of the second embodiment. The heater 230A is disposed on the outer surface SC of the cover layer 223. In this embodiment, the transparent conductive film 233A is disposed over the entire cover region Ac and part of the third peripheral region Ap3, and the pair of electrodes 234, 234 is disposed in the third peripheral region Ap3. The heater 230A may be attached to the cover layer 223 by an adhesive layer 240A. When a voltage is applied between the electrodes 234, 234, the transparent conductive film 233A generates heat, warming the metalens 220B.

[0059] In this embodiment, the light receiving optical system 210B includes a metalens 220B, and the heater 230A is disposed on the outer surface SC of the cover layer 223 included in the metalens 220B. This simplifies the configuration of the light receiving optical system 210B.

[0060] Additionally, in this embodiment, heater 230A is a transparent heater that includes transparent conductive film 233A and allows light to pass through. This configuration allows heater 230A to be disposed in cover region Ac, where light transmission is required, thereby expanding the options for disposing heater 230A. Additionally, by disposing heater 230A in cover region Ac, the region of metalens 220 that functions as a lens can be efficiently heated.

[0061] Fourth Embodiment A fourth embodiment will be described with reference to FIGS. 7 and 8. A measurement device 10C of this embodiment is a LiDAR that uses a surface-emitting laser as the light source 110 and is mounted on a vehicle. The measurement device 10C differs from the first embodiment in the configuration of a light projection optical system 180C (an example of a lens unit) provided in a projector 100C. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0062] As shown in Fig. 7 , the light projection optical system 180C is an optical component that is arranged on the optical path of the laser light emitted from the light source 110. As shown in Fig. 8 , the light projection optical system 180C includes a metalens 220C and a heater 230.

[0063] Metalens 220C includes a substrate 221 and a plurality of microstructures 222C arranged on the surface of substrate 221. The configuration of substrate 221 is the same as in the first embodiment. Microstructures 222C are minute protrusions protruding from the surface of substrate 221. The shape, size, and arrangement pattern of microstructures 222 are the same as in the first embodiment, except that metalens 220 is designed to function as a collimating lens that outputs light incident on incident surface SI as parallel light.

[0064] The heater 230 has the same configuration as in the first embodiment and is disposed in the second peripheral area Ap2, surrounding the entire back area Ab, as in the first embodiment.

[0065] As described above, the measurement apparatus 10C of this embodiment includes a light projection optical system 180C. The light projection optical system 180C includes a metalens 220C and a heater 230. The metalens 220C includes a substrate 221 and a plurality of microstructures 222C. The substrate 221 has an effective area Ae on the emission surface SO and allows light to pass through. The plurality of microstructures 222C are arranged in the effective area Ae. The heater 230 is arranged on the incidence surface SI of the substrate 221 provided in the metalens 220C. This configuration simplifies the configuration of the light projection optical system 180C.

[0066] (Modifications) The technology disclosed in this specification is not limited to the above-described embodiment and can be modified into various forms without departing from the spirit of the present invention. For example, the following modifications are also possible. (1) When the measurement device includes a light projector and a light receiver, both the light projector and the light receiver may include a lens unit, or either the light projector or the light receiver may include a lens unit. (2) In the above embodiment, the microstructures 222 and 222C are disposed on the exit surface SO of the substrate 221. However, the microstructures may be disposed on the entrance surface of the substrate. (3) In the above embodiment, both the entrance surface SI and the exit surface SO of the substrate 221 are flat. However, one of the entrance surface SI and the exit surface SO may be flat, or a portion of the entrance surface SI may be flat, or a portion of the exit surface SO may be flat, or the entire entrance surface SI and the exit surface SO may not be flat. In such a case, the heater may be disposed in a non-flat region of the surface of the substrate. (4) In the third embodiment, the outer surface SC of the cover layer 223 was a flat surface. However, a portion of the outer surface of the cover layer may be flat, and the entire outer surface may not be flat. In such cases, a heater may be disposed in the uneven region of the outer surface of the cover layer. (5) In the above embodiments, the heaters 230 and 230A were film heaters. However, the heaters do not have to be film heaters. For example, a heater pattern may be formed by applying a metal paste to the surface of the metalens by screen printing and then performing a necessary process such as heat treatment. (6) In the first and fourth embodiments, the heater 230 surrounded the entire back surface region Ab. However, the heater may partially surround the back surface region. (7) In the first and fourth embodiments, the heater 230A was disposed in the second peripheral region Ap2. However, the heater may be disposed in the first peripheral region, or in both the first and second peripheral regions. (8) In the second embodiment, the heater 230A is disposed over the entire rear surface area Ab. However, a transparent heater may be disposed in only a part of the rear surface area.In the third embodiment, the heater 230A was disposed over the entire cover region Ac, but a transparent heater may be disposed in only a portion of the cover region. (9) If the heater is a transparent heater, the transparent heater may be disposed in any region of the metalens surface except the effective region. For example, the transparent heater may be disposed in only one of the first peripheral region, the second peripheral region, and the rear surface region, or in two or more of the first peripheral region, the second peripheral region, and the rear surface region. Furthermore, if the metalens includes a cover layer, the transparent heater may be disposed in only one of the second peripheral region, the third peripheral region, the cover region, and the rear surface region, or in two or more of the second peripheral region, the third peripheral region, the cover region, and the rear surface region. (10) In the above embodiment, the light source 110 was a surface-emitting laser. However, the light source may be, for example, an edge-emitting laser, a fiber laser, or a light source other than a laser. (11) In the above embodiment, a LiDAR used in an on-vehicle AD or ADAS is exemplified as the measuring device, but the measuring device may be a device other than a LiDAR, or may be a measuring device used in a system other than an AD or ADAS. Alternatively, the lens unit may be a lens provided in a device or component other than the measuring device, for example, a lens provided in an on-vehicle lamp or camera. Alternatively, the lens may be a lens provided in a component for a purpose other than a vehicle, for example, a lens provided in a security camera or a lens provided in a smartphone camera.

[0067] This international application claims priority based on Japanese Patent Application No. 2024-125603, filed on August 1, 2024, the entire contents of which are incorporated herein by reference.

[0068] The above descriptions of specific embodiments of the present invention have been presented for purposes of illustration. They are not intended to be exhaustive or to limit the invention to the precise forms described. Numerous modifications and variations will be apparent to those skilled in the art in light of the above description.

[0069] 10, 10C: Measuring device 100, 100C: Light projector 110: Light source 120: Light projection control device 130: Current source 180: Light projection optical system 180C: Light projection optical system (lens unit) 200: Light receiver 210, 210A, 210B: Light receiving optical system (lens unit) 220, 220B, 220C: Metalens 221: Substrate 222, 222C: Microstructure 223: Cover layer 230, 230A: Heater 231, 232, 231A, 232A: Film 233: Conductive pattern 233A: Transparent conductive film 234, 234: Electrode 240, 240A: Adhesive layer 250: Light receiving unit 260: TOF measuring device 500: Information processing device 600: Communication interface 700: External device Ab: Back area Ac: Cover area Ae: Effective area Ap1: First peripheral area Ap2: Second peripheral area Ap3: Third peripheral area Lout: Output laser light Lre: Reflected laser light SC: Outer surface (surface) SI: Incident surface (surface, second surface) SO: Exit surface (surface, first surface) W: Measurement object

Claims

1. A lens unit comprising: a metalens comprising: a substrate having an effective area on its surface and allowing light to pass through; and a plurality of microstructures arranged in the effective area; and a heater disposed on the surface of the metalens.

2. A lens unit according to claim 1, wherein the metalens has a flat surface on its surface, and the heater is disposed on the flat surface.

3. A lens unit according to claim 1 or claim 2, wherein the surface of the substrate has a first surface and a second surface opposite to the first surface, the first surface has the effective area and a first peripheral area different from the effective area, the second surface has a back area located back to back with the effective area and a second peripheral area different from the back area, and the heater is disposed in at least one of the first peripheral area and the second peripheral area.

4. A lens unit according to claim 1 or 2, wherein the heater is a transparent heater that has a transparent conductive film and allows light to pass through.

5. A lens unit according to claim 4, wherein the surface of the substrate has a first surface and a second surface opposite to the first surface, the first surface has the effective area, the second surface has a back surface area located back to back with the effective area, and the heater is disposed in the back surface area.

6. A lens unit according to claim 4, wherein the metalens comprises a cover layer covering the microstructure, and the heater is disposed on a surface of the cover layer.

7. A measuring device comprising the lens unit according to claim 1 or 2 and a light receiver for receiving light reflected by an object to be measured.

8. A measuring device comprising the lens unit according to claim 1 or 2 and a projector that emits light to the outside.

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