Projector and measuring device

Abstract

To reduce adhesion of foreign matter to an output end of an optical fiber.SOLUTION: The projector includes a seed laser that emits seed laser light, an excitation laser that emits excitation laser light, an optical fiber that is optically connected to the seed laser and the excitation laser, is doped with a rare earth element excited by the excitation laser light, and has an output end from which output laser light is output, and a protective member that covers the output end.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] With the advancement of autonomous driving (AD) systems and advanced driver assistance systems (ADAS), research and development of LiDAR (light detection and ranging) is underway as one of the measurement devices used to grasp the surrounding environment and estimate the vehicle's self-position while driving. LiDAR includes a projector that projects laser light onto a measurement target and a photoreceiver 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 projector emits the laser light and the timing at which the photoreceiver receives the reflected light. The projector includes a fiber laser (see, for example, Patent Document 1). The fiber laser includes a seed laser that emits seed laser light, an optical fiber doped with a rare earth element and through which the seed laser light passes, and a pump laser that emits pump laser light that excites the rare earth element. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2020 / 117912 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned projector, it is desired to reduce adhesion of foreign matter to the output end of the optical fiber.

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

[0006] The technology disclosed in this specification can be realized, for example, in the following forms. (1) A light projector disclosed in this specification includes a seed laser, a pump laser, an optical fiber, and a protective member. The seed laser emits seed laser light. The pump laser emits pump laser light. The optical fiber is optically connected to the seed laser and the pump laser. The optical fiber is doped with a rare earth element that is excited by the pump laser light. The optical fiber has an output end from which output laser light is output, and the protective member covers the output end.

[0007] According to the above configuration, adhesion of foreign matter to the output end of the optical fiber is reduced.

[0008] (2) In the light projector described in (1) above, at least a part of the protective member may be a transmitting portion that transmits the output laser light.

[0009] According to this configuration, it is possible to cover the output end while allowing the output laser light to pass through the transmitting portion and be emitted to the outside of the protective member.

[0010] (3) In the floodlight described in (2) above, the protective member may comprise a base connected to the optical fiber, and a cover having the transmitting portion and removably connected to the base.

[0011] Such a configuration makes it easy to maintain the transmission section.

[0012] (4) In the light projector described in (2) or (3) above, the transmitting portion may be a beam splitter that reflects a portion of the output laser light and transmits the remainder, and the light projector may further include a sensor disposed inside the protective member that detects the output laser light reflected by the transmitting portion.

[0013] According to this configuration, there is no need to provide a separate, expensive splitter for splitting the output laser light to the sensor, and therefore the manufacturing costs of the projector are reduced.

[0014] (5) The light projector according to (2) or (3) above may further include a sensor disposed on the outer surface of the transmitting portion, for detecting the output laser light that has passed through the transmitting portion.

[0015] This configuration eliminates the need for an expensive separate splitter to split the output laser light to the sensor, reducing the manufacturing cost of the projector. In addition, maintenance of the sensor can be performed without removing the protective member from the optical fiber.

[0016] (6) In the light projector described in (1) above, the protective member may have an opening that allows the output laser light to pass through.

[0017] According to this configuration, it is possible to reduce the adhesion of foreign matter to the output end of the optical fiber while allowing the output laser light to be emitted to the outside of the protective member with a simple configuration.

[0018] (7) The measuring device disclosed in this specification includes the light projector according to any one of (1) to (6) above.

[0019] According to the above configuration, adhesion of foreign matter to the output end of the optical fiber is reduced.

[0020] The technology disclosed in this specification can be realized in various forms, for example, in the form of a projector, a measuring device, etc. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a block diagram showing a schematic configuration of a measurement device according to a first embodiment. [Figure 2] FIG. 1 is an explanatory diagram illustrating a schematic configuration of a floodlight according to a first embodiment; [Figure 3]FIG. 1 is a partially enlarged cross-sectional view showing an output end of a second optical fiber and a protective member disposed on the output end in the first embodiment; [Figure 4] FIG. 10 is a partially enlarged cross-sectional view showing the output end of the second optical fiber and the protective member disposed on the output end in the second embodiment; [Figure 5] FIG. 10 is a partially enlarged cross-sectional view showing the output end of the second optical fiber and the protective member disposed on the output end in the third embodiment; DETAILED DESCRIPTION OF THE INVENTION

[0022] (First embodiment) A first embodiment will be described with reference to FIGS. 1 to 3. A measuring device 10 of this embodiment is a LiDAR that uses a fiber laser as a light source. The measuring device 10 is mounted on a vehicle equipped with, for example, an AD (automated drive) or an ADAS (advanced driver assistance system). For example, the measuring 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 measurement device 10 includes a light projector 100, a scanning unit 300, a light receiver 400, an information processing device 500, and a communication interface 600.

[0024] As shown in FIGS. 1 and 2, the floodlight 100 includes a light source unit 110 and a control circuit board 210.

[0025] As shown in Figures 2 and 3, the light source unit 110 includes a seed laser 120, an excitation laser 130, a first optical fiber 140, a second optical fiber 150 (an example of an optical fiber), a first isolator 161, a first multiplexer 162, a second isolator 163, a second multiplexer 164, a first demultiplexer 165, a protective member 170, a light projection optical system 180, and a sensor 190.

[0026] The seed laser 120 is a laser light source that emits seed laser light La having a peak wavelength within the near-infrared range. In this embodiment, the wavelength of the seed laser light La is 1550 nm.

[0027] The pumping laser 130 is a laser light source and emits pumping laser light Lb. In this embodiment, the wavelength of the pumping laser light Lb is 940 nm.

[0028] The first optical fiber 140 includes a core doped with a rare earth element and a cladding surrounding the core and having a refractive index lower than the maximum refractive index of the core. The rare earth element is an element that is excited by the excitation laser light Lb. Examples of rare earth elements include ytterbium (Yb) and erbium (Er). The second optical fiber 150 is similar. The length of each optical fiber 140, 150 is, for example, approximately 5 m.

[0029] The first isolator 161 and the second isolator 163 are optical components that allow light to pass only in the forward direction from the seed laser 120 toward the light projecting optical system 180 and block light in the opposite direction to the forward direction. The first isolator 161 is optically connected to the seed laser 120. The second isolator 163 is optically connected to the output end of the first optical fiber 140. The isolators 161 and 163 suppress damage to the seed laser 120 due to return light from the optical fibers 140 and 150 flowing back into the seed laser 120.

[0030] The first demultiplexer 165 is an optical component that splits input light into multiple beams. The first demultiplexer 165 is, for example, a tap coupler, and includes an input port optically connected to the pump laser 130 and two output ports optically connected to the first multiplexer 162 and the second multiplexer 164, respectively.

[0031] The first multiplexer 162 and the second multiplexer 164 are optical components that multiplex multiple input beams. The first multiplexer 162 and the second multiplexer 164 are, for example, WDM (wavelength division multiplexing) couplers. The first multiplexer 162 has two input ports optically connected to the first isolator 161 and the first demultiplexer 165, respectively, and an output port optically connected to the input end of the first optical fiber 140. The second multiplexer 164 has two input ports optically connected to the second isolator 163 and the other output port of the first demultiplexer 165, respectively, and an output port optically connected to the input end of the second optical fiber 150.

[0032] The first optical fiber 140 and the second optical fiber 150 are connected in series via a second isolator 163 and a second multiplexer 164 .

[0033] The protection member 170 is attached to the second optical fiber 150 and covers the output end 151 of the second optical fiber 150. The protection member 170 includes a base 171 and a cover 172.

[0034] The base 171 is a member fixed to the second optical fiber 150. The cover 172 includes a cover main body 173 and a transparent member 175 (an example of a transparent portion). The cover main body 173 is a member that is removably attached to the base 171. The cover main body 173 has a through-hole 174. The through-hole 174 is arranged at a position on the optical path of the output laser light Lout output from the output end 151 of the second optical fiber 150. The through-hole 174 is closed by fitting the transparent member 175. In this embodiment, the transparent member 175 is a plate-type beam splitter that reflects a portion of the output laser light Lout and transmits the remainder. The transparent member 175 is arranged on the optical path of the output laser light Lout output from the output end 151.

[0035] The protective member 170 is a container sealed by a base 171 and a cover 172, and houses the output end 151 of the second optical fiber 150 and its vicinity therein. The base 171 and the cover 172 may be made of, for example, metal or synthetic resin.

[0036] The sensor 190 is a light-receiving sensor that is disposed inside the protective member 170 and detects the output laser light Lout reflected by the transparent member 175. The sensor 190 may be adhered to the inner surface of the cover main body 173. The sensor 190 includes a light-receiving element. The light-receiving element is, for example, a photodiode. The sensor 190 converts the received output laser light Lout into a detection signal corresponding to the intensity of the output laser light Lout and outputs the detection signal to the light-projection control device 211.

[0037] The projection optical system 180 is an optical component arranged on the optical path of the output laser light Lout that has passed through the transparent member 175. The projection optical system 180 may be, for example, a collimator lens that adjusts the output laser light Lout to be parallel light.

[0038] The control circuit board 210 is a circuit board on which electronic components are mounted for controlling the light emission of the seed laser 120 and the excitation laser 130, and as shown in FIG. 2, includes a light projection control device 211, a first current source 221, and a second current source 222.

[0039] The light projection control device 211 is, for example, a microcomputer and includes a processor and a storage device. The processor is, for example, a CPU (central processing unit). The storage device includes, for example, a ROM (read only memory) and a RAM (random access memory). 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. For example, the storage device stores a computer program for controlling the intensity of the excitation laser beam Lb. This computer program may be provided in a state where it is stored in a computer-readable recording medium (not shown). The computer-readable recording medium is, for example, a CD-ROM, a DVD-ROM, or a USB memory. Alternatively, the computer program may be provided in a state where it can be obtained from an external device (for example, a server on the cloud) via the communication interface 600.

[0040] The first current source 221 and the second current source 222 are general current circuits including, for example, a capacitor, a resistor, and a switching element. The first current source 221 supplies a drive current to the seed laser 120. The second current source 222 supplies a drive current to the pump laser 130.

[0041] The light-projection control device 211 outputs a drive signal to a first current source 221. The first current source 221 receives the drive signal, generates a drive current corresponding to the drive signal, and supplies the drive current to the seed laser 120. The light-projection control device 211 outputs the drive signal to a second current source 222. The second current source 222 receives the drive signal, generates a drive current corresponding to the drive signal, and supplies the drive current to the pump laser 130. In addition, the light-projection control device 211 outputs a signal indicating the light emission timing at which the seed laser 120 emits the seed laser light La.

[0042] The scanning unit 300 is disposed on the optical path of the output laser light Lout output from the projector 100. The scanning unit 300 is a device for irradiating a measurement area with the output laser light Lout in a predetermined scanning pattern. The scanning unit 300 may include, for example, a micro electro mechanical systems (MEMS) mirror, a digital micromirror device (DMD), a galvanometer mirror, or a polygon mirror.

[0043] As shown in FIG. 1, the light receiver 400 includes a light receiving optical system 410, a light receiving unit 420, and a TOF measurement device 430.

[0044] The light receiving optical system 410 is an optical component for causing the light receiving unit 420 to receive reflected laser light Lre, which is light that is output laser light Lout reflected by the measurement target W and returned. The light receiving optical system 410 may be, for example, any of various lenses such as a condenser lens, any of various filters such as a wavelength filter, or a reflecting mirror.

[0045] The light receiving unit 420 includes a light receiving element, such as a photodiode. The light receiving element receives the reflected laser light Lre incident from the light receiving optical system 410, 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 signal.

[0046] The TOF measurement device 430 has, for example, a time measurement IC (integrated circuit) equipped with a TDC (time-to-digital converter) circuit. The TOF measurement device 430 is communicably connected to the light-projection control device 211 and the light-receiving unit 420. The TOF measurement device 430 receives a timing signal indicating the light emission timing output from the light-projection control device 211 and a light-receiving signal output from the light-receiving unit 420. Based on these signals, the TOF measurement device 430 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 430 outputs a signal corresponding to the calculated TOF and the light-receiving signal received from the light-receiving unit 420.

[0047] 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 430. The information processing device 500 receives a signal corresponding to the TOF output by the TOF measurement device 430 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.

[0048] 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).

[0049] Next, the basic operation of the projector 100 will be described. The light-projection control device 211 pulse-controls the seed laser 120. That is, the light-projection control device 211 outputs a drive signal to the first current source 221 so that the seed laser 120 intermittently outputs seed laser light La at predetermined timings. The first current source 221 generates a pulse current having a frequency and magnitude corresponding to the received drive signal and supplies it to the seed laser 120. The seed laser 120 outputs seed laser light La having a frequency and intensity corresponding to the supplied drive current.

[0050] The light-projection control device 211 controls the pump laser 130 with a direct current. That is, the light-projection control device 211 outputs a drive signal to the second current source 222 so that the pump laser 130 continuously outputs the pump laser light Lb. The second current source 222 supplies the pump laser 130 with a drive current having a magnitude corresponding to the received drive signal. The pump laser 130 outputs the pump laser light Lb having an intensity corresponding to the supplied drive current.

[0051] The first demultiplexer 165 demultiplexes the pumping laser light Lb input from the pumping laser 130 into two beams, and outputs them to the first multiplexer 162 and the second multiplexer 164 .

[0052] The seed laser light La output from the seed laser 120 passes through a first isolator 161 and is input to a first multiplexer 162. The first multiplexer 162 multiplexes the seed laser light La input from the seed laser 120 and the excitation laser light Lb input from a first demultiplexer 165, and outputs the multiplexed light to the first optical fiber 140.

[0053] The rare earth element doped in the first optical fiber 140 absorbs and is excited by the pump laser light Lb. A sufficient supply of the pump laser light Lb creates a population inversion. A population inversion is a state in which the number of atoms in an excited state is greater than the number of atoms in a ground state. When seed laser light La is input to the first optical fiber 140 in this state, electrons in the excited atoms move to a lower energy level and emit light having the same wavelength as the seed laser light La. This is called stimulated emission. The seed laser light La is amplified by stimulated emission. The amplified seed laser light La output from the first optical fiber 140 passes through the second isolator 163 and is input to the second multiplexer 164. The second multiplexer 164 multiplexes this seed laser light La with the pump laser light Lb input from the first demultiplexer 165 and outputs the combined light to the second optical fiber 150.

[0054] Inside the second optical fiber 150, the seed laser light La is amplified, similarly to the first optical fiber 140. The amplified seed laser light La is output from the second optical fiber 150 as output laser light Lout. The transparent member 175 reflects a portion of the output laser light Lout and guides it to the sensor 190, and transmits the remainder and guides it to the light projecting optical system 180. The output laser light Lout that has passed through the transparent member 175 is output to the outside of the projector 100 via the light projecting optical system 180.

[0055] The output end 151 of the second optical fiber 150 has a diameter of about 10 μm and an extremely small area. From the output end 151 having such a small area, an output laser light Lout having a high optical energy of 1000 W or more is emitted. Therefore, if foreign matter such as dust, dirt, fiber waste, or deposits from metal gas adheres to the output end 151, the foreign matter may be burned by the high optical energy of the output laser light Lout, thereby reducing the intensity of the output laser light Lout.

[0056] In this embodiment, the output end 151 is covered with the protective member 170, so that adhesion of foreign matter to the output end 151 is reduced, and a decrease in the intensity of the output laser light Lout is suppressed.

[0057] Furthermore, in this embodiment, the protective member 170 includes a base 171 connected to the second optical fiber 150 and a cover 172 removably connected to the base 171. The cover 172 includes a transparent member 175 that reflects a portion of the output laser light Lout and transmits the remainder. A sensor 190 that detects the output laser light Lout reflected by the transparent member 175 is disposed inside the cover 172. With this configuration, the transparent member 175 does not prevent the output laser light Lout from being emitted to the outside of the protective member 170, and the protective member 170 can be made into a sealed container. This effectively reduces the adhesion of foreign matter to the output end 151. Furthermore, since there is no need to separately provide an expensive demultiplexer that demultiplexes the output laser light Lout to the sensor 190, the manufacturing cost of the floodlight 100 is reduced. In addition, since the cover 172 is detachable from the base 171, maintenance of the transparent member 175 and the sensor 190 is facilitated.

[0058] As described above, the measuring apparatus 10 of this embodiment includes the projector 100. The projector 100 includes the seed laser 120, the pumping laser 130, the second optical fiber 150, and the protective member 170. The seed laser 120 emits seed laser light La. The pumping laser 130 emits pumping laser light Lb. The second optical fiber 150 is optically connected to the seed laser 120 and the pumping laser 130. The second optical fiber 150 is doped with a rare earth element that is pumped by the pumping laser light Lb. The second optical fiber 150 has an output end 151 from which the output laser light Lout is output. The protective member 170 covers the output end 151.

[0059] According to the above configuration, the output end 151 of the second optical fiber 150 is covered with the protective member 170, so that adhesion of foreign matter to the output end 151 is reduced.

[0060] In this embodiment, a part of the protective member 170 is a transparent member 175 that transmits the output laser light Lout. The presence of this transparent member 175 makes it possible to make the protective member 170 into a sealed container without preventing the output laser light Lout from being emitted to the outside of the protective member 170. This effectively reduces adhesion of foreign matter to the output end 151.

[0061] In this embodiment, the protective member 170 includes a base 171 connected to the second optical fiber 150 and a cover 172 detachably connected to the base 171, and the cover 172 includes a transparent member 175. With this configuration, maintenance of the transparent member 175 becomes easy.

[0062] In this embodiment, the transparent member 175 is a beam splitter that reflects a portion of the output laser light Lout and transmits the remainder, and the projector 100 further includes a sensor 190 that is disposed inside the protective member 170 and detects the output laser light Lout reflected by the transparent member 175. With this configuration, there is no need to separately provide an expensive branching filter that branches the output laser light Lout to the sensor 190, and therefore the manufacturing cost of the projector 100 is reduced.

[0063] (Second embodiment) The second embodiment will be described with reference to FIG. 4. Similar to the first embodiment, the floodlight 100A of this embodiment is provided in a LiDAR that uses a fiber laser as a light source. The floodlight 100A of this embodiment differs from the first embodiment in the configuration of the protection member 170A. 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.

[0064] Similar to the first embodiment, the protection member 170A is a member that is attached to the second optical fiber 150 and covers the output end 151 of the second optical fiber 150. The protection member 170A includes a base 171 and a cover 172A.

[0065] The cover 172A includes a cover main body 173, as in the first embodiment, and the cover main body 173 has a through-hole 174. The through-hole 174 is closed by fitting a transparent member 175A (an example of a transparent portion). The transparent member 175A is a member that allows the output laser light Lout to pass through. The transparent member 175A of this embodiment does not necessarily have the function of reflecting a portion of the output laser light Lout. The transparent member 175A may be formed of a material that is commonly used as a cover for an illumination device, such as polycarbonate. The transparent member 175A is disposed on the optical path of the output laser light Lout output from the output end 151. The protective member 170 is a container sealed by the base 171 and the cover 172A, and the output end 151 of the second optical fiber 150 and its neighboring portion are housed therein.

[0066] The sensor 190A is a light-receiving sensor that is disposed outside the protective member 170A and detects the output laser light Lout that has passed through the transparent member 175A. The sensor 190A is bonded to the outer surface of the transparent member 175A and disposed on the optical path of the output laser light Lout. The sensor 190A includes a light-receiving element. The light-receiving element is, for example, a photodiode. The sensor 190A converts the received output laser light Lout into a detection signal corresponding to the intensity of the output laser light Lout and outputs the detection signal to the light-projection control device 211.

[0067] In this embodiment, as in the first embodiment, the output end 151 of the second optical fiber 150 is covered with the protective member 170A, thereby reducing the adhesion of foreign matter to the output end 151. In addition, the light projector 100A of this embodiment further includes a sensor 190A that is disposed on the outer surface of the transparent member 175A and detects the output laser light Lout that has transmitted through the transparent member 175A. This configuration eliminates the need to separately provide an expensive demultiplexer for demultiplexing the output laser light Lout to the sensor 190A, thereby reducing the manufacturing cost of the light projector 100A. In addition, maintenance of the sensor 190A can be performed without removing the protective member 170A from the second optical fiber 150.

[0068] (Third embodiment) A third embodiment will be described with reference to FIG. 5. A floodlight 100B of this embodiment is provided in a LiDAR that uses a fiber laser as a light source, similar to the first embodiment. The floodlight 100B of this embodiment differs from the first embodiment in the configuration of a protective member 170B. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and descriptions thereof will be omitted.

[0069] Similar to the first embodiment, the protective member 170B is a member that is connected to the second optical fiber 150 and covers the output end 151 of the second optical fiber 150. Unlike the above embodiment, the protective member 170 is integrally formed as a single member. The protective member 170 may be made of, for example, metal or resin.

[0070] The protective member 170B has a through-hole 174B (an example of an opening). The through-hole 174B is disposed at a position on the optical path of the output laser light Lout output from the output end 151 of the second optical fiber 150, and allows the output laser light Lout to pass through. Unlike the above embodiment, the protective member 170B is a container with an opening that is not sealed by a member that blocks the through-hole 174B. The output end 151 of the second optical fiber 150 and a portion nearby are housed inside the protective member 170B.

[0071] The projector 100B further includes a second demultiplexer 176 and a sensor 190B. The second demultiplexer 176 is disposed on the optical path of the output laser light Lout that passes through the through-hole 174B and is emitted to the outside of the protective member 170B. The second demultiplexer 176 is an optical component that demultiplexes the output laser light Lout and guides it to the sensor 190B and the projecting optical system 180. The second demultiplexer 176 may be a beam splitter that reflects a portion of the output laser light Lout and guides it to the sensor 190B, and transmits the remainder and guides it to the projecting optical system 180.

[0072] The sensor 190B is a light-receiving sensor that is disposed outside the protective member 170B and detects a portion of the output laser light Lout that has been branched by the second branching filter 176. The sensor 190B includes a light-receiving element. The light-receiving element is, for example, a photodiode. The sensor 190 converts the received output laser light Lout into a detection signal corresponding to the intensity of the output laser light Lout and outputs the detection signal to the light-projection control device 211.

[0073] In this embodiment, as in the first embodiment, the output end 151 of the second optical fiber 150 is covered with the protective member 170B, thereby reducing adhesion of foreign matter to the output end 151. In addition, in this embodiment, the protective member 170B has a through hole 174B that allows the output laser light Lout to pass through. With this configuration, it is possible to reduce adhesion of foreign matter to the output end 151 of the second optical fiber 150 with a simple configuration while allowing the output laser light Lout to be emitted to the outside of the protective member 170B.

[0074] (Variation) The technology disclosed in this specification is not limited to the above-described embodiments, and can be modified into various forms without departing from the spirit thereof, for example, the following modifications are also possible. (1) In the above embodiment, the projectors 100, 100A, and 100B are provided with a first optical fiber 140 and a second optical fiber 150, and the seed laser light La is amplified in two stages. However, the projector may amplify the seed laser light in only one stage using one optical fiber, or may amplify the seed laser light in three or more stages using three or more optical fibers. (2) In the above embodiment, the projectors 100, 100A, and 100B are of a forward pumping type in which the pumping laser light Lb is input from the input end of the first optical fiber 140. However, the projectors may be of a backward pumping type in which the pumping laser light is input from the output end of the optical fiber. (3) In the first embodiment, the protective member 170 includes the base 171 and the cover 172, and part of the cover 172 is the transparent member 175. However, the protective member may be integrally formed as a single member, part of which is the transparent portion. The same applies to the second embodiment. (4) In the first and second embodiments, a portion of the cover 172, 172A is the transparent member 175, 175A, but the entire cover may be the transparent portion, or both the cover and the base may be the transparent portion. Alternatively, the protective member may be integrally formed as a single member, and the entire protective member may be the transparent portion. (5) In the third embodiment, the protective member 170B is integrally formed as a single member and has a through hole 174B. However, for example, the protective member may have a base and a cover, and the cover may have an opening that allows the output laser light to pass through. (6) In the first and second embodiments, the protective members 170, 170A are in the form of sealed containers. However, the protective members may have openings for, for example, maintenance of the output terminals or sensors arranged inside. (7) In the first embodiment, the sensor 190 is disposed on the inner surface of the cover 172. However, the sensor may be disposed at any position as long as it can receive the output laser light. For example, the sensor may be disposed on the inner surface of the base. (8) In the second embodiment, the sensor 190A is disposed on the outer surface of the transparent member 175A. However, the sensor may be disposed at any position where it can receive the output laser light. For example, the sensor may be disposed outside the protective member, on the optical path of the output laser light, and away from the transparent member. Alternatively, an optical component may be disposed outside the protective member that splits the output laser light and guides it to the sensor and the projection optical system. [Explanation of symbols]

[0075] 10: Measuring device 100, 100A, 100B: Light projector 110: Light source unit 120: Seed laser 130: Pumping laser 140: First optical fiber 150: Second optical fiber (optical fiber) 151: Output end 161: First isolator 162: First multiplexer 163: Second isolator 164: Second multiplexer 165: First demultiplexer 170, 170A, 170B: Protective member 171: Base 172, 172A: Cover 173: Cover body 174: Through hole 174B: Through hole (opening) 175, 175A: Transparent member (transmitting portion) 176: Second demultiplexer 180: Light projecting optical system 190, 190A, 190B: Sensor 210: Control circuit board 211: Light projection control device 221: First current source 222: Second current source 300: Scanning unit 400: Photoreceiver 410: Light receiving optical system 420: Photoreceiving section 430: TOF measurement device 500: Information processing device 600: Communication interface 700: External device La: Seed laser light Lb: Excitation laser light Lout: Output laser light Lre: Reflected laser light W: Measurement object

Claims

1. a seed laser that emits seed laser light; an excitation laser that emits excitation laser light; an optical fiber optically connected to the seed laser and the pumping laser, doped with a rare earth element that is excited by the pumping laser light, and having an output end from which an output laser light is output; a protective member covering the output end; Equipped with Floodlight.

2. 2. The floodlight according to claim 1, At least a part of the protective member is a transmission portion that transmits the output laser beam. Floodlight.

3. 3. The floodlight according to claim 2, The protective member is a base portion connected to the optical fiber; a cover comprising the transmission portion and removably connected to the base; Floodlight.

4. The floodlight according to claim 2 or 3, the transmitting portion is a beam splitter that reflects a portion of the output laser light and transmits the remainder, a sensor disposed inside the protective member and configured to detect the output laser light reflected by the transmission portion; Floodlight.

5. The floodlight according to claim 2 or 3, a sensor disposed on an outer surface of the transmission portion and configured to detect the output laser light transmitted through the transmission portion; Floodlight.

6. 2. The floodlight according to claim 1, the protective member has an opening that allows the output laser light to pass through. Floodlight.

7. A measuring device comprising the light projector according to claim 1 or 2.

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