Optical measurement device

Abstract

The present disclosure provides an optical measurement device capable of enhancing resolution without increasing a physical size of an optical device.　An optical measurement device (1) according to an embodiment of the present disclosure is provided with: an optical device (100) that emits variable-wavelength light; a lens (200) through which the light passes; and a diffraction grating (300) that converts the light into a plurality of diffracted lights.

Description

Optical Measurement Device

[0001] The present disclosure relates to optical metrology devices.

[0002] In recent years, light detection and ranging (LiDAR) has been developed as an optical measurement device that uses a photonic integration circuit (PIC) in which optical components such as silicon (Si) waveguides are stacked on a silicon-on-insulator (SOI) substrate. Among light detection and ranging (LiDAR), a frequency-modulated continuous wave (FMCW) LiDAR is known, which includes an optical device that emits laser light whose wavelength changes over time.

[0003] In an optical measurement instrument equipped with the above-described optical device, in order to increase the resolution, it becomes necessary to physically increase the number of beam irradiation points on the optical device, which results in an increase in the physical size of the optical device.

[0004] US Patent Application Publication No. 2021 / 0018598

[0005] The present disclosure provides an optical metrology apparatus that can increase resolution without increasing the physical size of an optical device.

[0006] An optical measurement apparatus according to an embodiment of the present disclosure includes an optical device that emits wavelength-tunable light, a lens through which the light passes, and a diffraction grating that converts the light into a plurality of diffracted beams.

[0007] The plurality of lenses may be arranged in a straight line along the direction in which the light travels.

[0008] The lens may have a diffraction grating pattern radiating from the center of the body.

[0009] The diffraction grating may have a blade-like uneven shape.

[0010] The diffraction grating may have a columnar concave-convex shape.

[0011] The diffraction grating pattern may be a square arrangement.

[0012] The diffraction grating pattern may be a hexagonal arrangement.

[0013] The planar shape of the diffraction grating may be circular, polygonal, or cross-shaped.

[0014] The diffraction grating may have a plurality of slits, and the spacing between the slits formed in the central region of the diffraction grating may be largest.

[0015] The diffraction grating may have a plurality of diamond-shaped slits arranged in a multi-layered manner.

[0016] A plurality of the lenses and a plurality of the diffraction gratings may be arranged in a row.

[0017] A plurality of the lenses and a plurality of the diffraction gratings may be arranged in a matrix.

[0018] The lens may be disposed between the optical device and the diffraction grating.

[0019] The diffraction grating may be disposed between the optical device and the lens.

[0020] The lens may include: a first lens disposed between the optical device and the diffraction grating; and a second lens disposed in front of the diffraction grating in the direction in which the diffracted light travels.

[0021] The first lens may be divided into a first portion and a second portion.

[0022] The optical measurement apparatus may further include a microlens array disposed between the optical device and the lens.

[0023] The microlens array may be integrated with the optical device.

[0024] The diffraction grating may be a reflective diffraction grating.

[0025] The lens and the diffraction grating may be integrated.

[0026] 1B is a plan view of an optical measurement device according to the first embodiment; FIG. 1C is a cross-sectional view of the optical detection device shown in FIG. 1A; FIG. 1D is a block diagram showing a configuration of an optical device according to the first embodiment; FIG. 1E is a diagram showing a first layout example of an optical antenna 150; FIG. 1F is a diagram showing a second layout example of the optical antenna 150; FIG. 1G is a plan view showing a first structural example of an optical antenna; FIG. 1H is a cross-sectional view showing a first structural example of an optical antenna; FIG. 1I is a plan view showing a second structural example of an optical antenna; FIG. 1J is a cross-sectional view showing a second structural example of an optical antenna; FIG. 1J is a cross-sectional view showing a second structural example of an optical antenna; FIG. 1J is a cross-sectional view showing a third structural example of an optical antenna; FIG. 1J is a cross-sectional view showing a third structural example of an optical antenna; FIG. 1J is a cross-sectional view showing a fourth structural example of an optical antenna; FIG. 1J is a cross-sectional view showing a fourth structural example of an optical antenna; FIG. 1J is a plan view showing a second structural example of a lens; FIG. 1J is a cross-sectional view showing a second structural example of a lens; FIG. 1J is a cross-sectional view showing a third structural example of a lens; FIG. 1J is a cross-sectional view showing a third structural example of a lens; FIG. 1J is a plan view showing a first structural example of a diffraction grating; FIG. 1J is a cross-sectional view showing a first structural example of a diffraction grating; FIG. 1J is a cross-sectional view showing a second structural example of a diffraction grating; FIG. 1J is a cross-sectional view showing a third structural example of a diffraction grating. 16A ; FIG. 17A is an enlarged view of a diffraction grating pattern of a diffraction grating according to a third structural example; FIG. 18 is a plan view showing a fourth structural example of a diffraction grating; FIG. 19 is a plan view showing a fifth structural example of a diffraction grating; FIG. 20 is a plan view showing a sixth structural example of a diffraction grating; FIG. 21 is a plan view showing a seventh structural example of a diffraction grating; FIG. 22 is a graph showing the relationship between position and phase in a cross section taken along the cutting line A1-A1 of FIG. 15A; FIG. 23 is a plan view showing an eighth structural example of a diffraction grating; FIG. 24 is a graph showing the relationship between position and phase in a cross section taken along the cutting line A2-A2 of FIG. 16A; FIG. 25 is a plan view showing a ninth structural example of a diffraction grating; FIG. 26 is a graph showing the relationship between position and phase in a cross section taken along the cutting line A3-A3 of FIG. 17A; FIG. 27 is a diagram showing a projected spot distribution when first light is diffracted by a diffraction grating divided by equally spaced slits; FIG. 28 is a diagram showing a projected spot distribution when first light is diffracted by a diffraction grating divided by slits according to a seventh structural example; FIG. 29 is a diagram showing a projected spot distribution when first light is diffracted by a diffraction grating divided by slits according to an eighth structural example; 10A and 10B are plan views of an optical measurement device according to a first modified example and a second modified example, respectively.1. A cross-sectional view of an optical measurement device according to a third modified example. 2. A cross-sectional view of an optical measurement device according to a fourth modified example. 3. A cross-sectional view of an optical measurement device according to a fifth modified example. 4. A cross-sectional view of an optical measurement device according to the second embodiment. 5. A cross-sectional view of an optical measurement device according to the sixth modified example. 6. A cross-sectional view of an optical measurement device according to the seventh modified example. 7. A cross-sectional view of an optical measurement device according to the third embodiment. 8. A cross-sectional view of an optical measurement device according to the fourth embodiment. 9. A plan view of an optical measurement device according to the fifth embodiment. 10. A cross-sectional view of an optical measurement device according to the fifth embodiment. 11. A block diagram showing an example of a schematic configuration of a vehicle control system. 12. An explanatory diagram showing an example of the installation positions of an outside vehicle information detection unit and an imaging unit.

[0027] Hereinafter, specific embodiments to which the present technology is applied will be described in detail with reference to the drawings. The drawings are schematic or conceptual, and the proportions of each part are not necessarily the same as those in reality. In the specification and drawings, elements similar to those described above with reference to the previous drawings are designated by the same reference numerals, and detailed descriptions thereof will be omitted as appropriate.

[0028] First Embodiment Fig. 1A is a plan view of an optical measurement device according to a first embodiment. Fig. 1B is a cross-sectional view of the optical detection device shown in Fig. 1A. As shown in Figs. 1A and 1B, an optical device 100 according to this embodiment includes an optical device 100, a lens 200, and a diffraction grating 300. In this embodiment, the lens 200 is disposed on the optical device 100. Furthermore, the diffraction grating 300 is disposed on the lens 200. Each optical element will be described below.

[0029] Fig. 2 is a block diagram showing the configuration of an optical device according to the first embodiment. The optical device 100 shown in Fig. 1 is an example of a distance measuring device, and includes a light source 101, a splitter 102, a circulator 103, a switch array 104, an antenna array 105, a coupler 106, a photodetector 107, and a switch control circuit 108.

[0030] The light source 101 emits wavelength-tunable laser light L0. Examples of light sources that can be used as the light source 101 include a distributed feedback (DFB) laser, a distributed Bragg reflector (DBR) laser, a ring resonator laser, a vertical cavity surface emitting laser (VCSEL), and a photonic crystal laser. When the light source 101 is a ring resonator laser or a DBR laser, the linewidth of the laser light L0 can be narrowed and the wavelength tunable range can be expanded compared to a DFB laser. Furthermore, when the light source 101 is a surface-emitting light source such as a VCSEL, the power conversion efficiency can be improved compared to a DFB laser.

[0031] The splitter 102 splits the laser light L0 into a first light L1 and a second light L2. The split ratio between the first light L1 and the second light L2 may be 1:1 or any other ratio. The first light L1, which is one of the split lights of the laser light L0, enters the circulator 103. The second light L2, which is the other of the split lights of the laser light L0, enters the coupler 106. The splitter 102 may be, for example, a 1x2 multimode interference (MMI) coupler, a 2x2 MMI coupler, a directional coupler, or a bending directional coupler.

[0032] The circulator 103 transfers the first light L1 split by the splitter 102 to the switch array 104. The circulator 103 also transfers the third light L3 input from the antenna array 105 via the switch array 104 to the coupler 106. The circulator 103 can be a polarization-independent optical circulator element including, for example, a 2×2 coupler, a directional coupler, a bending directional coupler, a Faraday rotator, a half-wave plate, and a polarization beam splitter, a reflecting mirror, or a prism.

[0033] The switch array 104 performs a switching operation to selectively pass the first light L1 to each optical antenna 150 of the antenna array 105. The switch array 104 also performs a switching operation to selectively pass the third light L3 from the antenna array 105 to the circulator 103. The multiple switch elements that make up the switch array 104 can be, for example, a Mach-Zehnder interferometer including a heater for a waveguide, a ring modulation switch including a heater for a waveguide, a Mach-Zehnder interferometer including a junction (PN interface), a ring modulation switch including a junction (PN interface), a MEMS (Micro Electro Mechanical Systems) optical switch, a Mach-Zehnder interferometer having a ferroelectric film, and a ring modulation switch including a ferroelectric film.

[0034] An arrayed waveguide grating (AWG) can also be used as the switch element of the switch array 104. In this case, the light source 101 is provided with a circuit for controlling the wavelength of the laser light L0, and each switch array 104 outputs the laser light L0 corresponding to the controlled wavelength.

[0035] The antenna array 105 has a plurality of optical antennas 150 arranged in a two-dimensional array. The optical antenna 150 selected by the switch array 104 emits a first light L1 toward the object 1000. The optical antenna 150 selected by the switch array 104 also outputs a third light L3 reflected by the object 1000 as received light to the circulator 103. Each optical antenna 150 can be, for example, a fan grating coupler, a wide waveguide grating coupler, a waveguide with a diffraction grating, a photonic crystal waveguide with a diffraction grating, or a spot size converter.

[0036] Fig. 3A is a diagram showing a first layout example of the optical antenna 150. In Fig. 3A, the multiple optical antennas 150 are arranged in a square. That is, the multiple optical antennas 150 are arranged at equal intervals in the vertical and horizontal directions at a pitch P. However, the layout of the optical antennas 150 is not limited to the square arrangement shown in Fig. 3A.

[0037] Fig. 3B is a diagram showing a second layout example of the optical antenna 150. In Fig. 3B, the optical antennas 150 are arranged in a staggered manner. That is, the rows of the optical antennas 150 arranged in the vertical direction are shifted by half a pitch (1 / 2P).

[0038] FIG. 4A is a plan view showing a first structural example of the optical antenna. FIG. 4B is a cross-sectional view showing the first structural example of the optical antenna. The optical antenna 150a shown in FIGS. 4A and 4B is a passive optical antenna and includes a waveguide 151, a diffraction grating 152, and a cladding layer 153. The waveguide 151 guides the first light L1. The diffraction grating 152 is formed on the surface of the first light L1. The cladding layer 153 covers the first light L1 and the diffraction grating 152. In this optical antenna 150a, the first light L1 traveling through the waveguide 151 is converted by the diffraction grating 152 into a plurality of diffracted light beams L11 that form a refractive index distribution with a constant period. Controlling the periodic refractive index distribution in this manner enables fine adjustment of beam formation according to the optical characteristics of the lens 200.

[0039] Fig. 5A is a plan view showing a second structural example of the optical antenna. Fig. 5B is a cross-sectional view showing the second structural example of the optical antenna. The optical antenna 150b shown in Figs. 5A and 5B is an active optical antenna, and has a waveguide 151, a diffraction grating 152, a cladding layer 153, and a heater 154. The waveguide 151, the diffraction grating 152, and the cladding layer 153 are the same as those in the first structural example, and therefore their description will be omitted.

[0040] The heater 154 is disposed within the cladding layer 153. When a current I is applied to the heater 154, the heater 154 generates heat and heats the diffraction grating 152. As a result, the refractive index of the first light L1 can be controlled by the thermo-optic effect. This allows the operating wavelength of the first light L1 to be controlled, thereby achieving a calibration effect. Furthermore, the diffraction grating 152 forms a refractive index distribution for the first light L1, thereby improving the degree of freedom in beam formation. Note that, although the heater 154 indirectly heats the diffraction grating 152 via the cladding layer 153 in FIG. 5A , the heater 154 may also heat the diffraction grating 152 directly by contacting it.

[0041] FIG. 6A is a plan view showing a third example structure of the optical antenna. FIG. 6B is a cross-sectional view showing the third example structure of the optical antenna. In the optical antenna 150c shown in FIGS. 6A and 6B, the diffraction grating 152 is formed in a stepped shape within the cladding layer 153. Therefore, it is possible to impart two or more steps of refractive index difference between the top and bottom of the first light L1 traveling through the waveguide 151. This strengthens the asymmetry between the top and bottom of the diffracted light, thereby enhancing the interference of the upper diffracted light L11 with the lower diffracted light. As a result, it is possible to obtain the effect of improving the upward emissivity of the diffracted light.

[0042] Fig. 7A is a plan view showing a fourth structural example of the optical antenna. Fig. 7B is a cross-sectional view showing the fourth structural example of the optical antenna. The optical antenna 150d shown in Figs. 7A and 7B does not include a diffraction grating 152. Therefore, the first light L1 is emitted from the end face of the waveguide 151. In this structural example, the first light L1 is emitted directly into space, unlike radiation from the diffraction grating 152. As a result, the optical antenna 150d has a structure that is highly dependent on the wavelength of the first light L1.

[0043] The coupler 106 outputs a composite wave obtained by combining the second light L2 input from the splitter 102 and the third light L3 input from the circulator 103 to the photodetector 107 .

[0044] The photodetector 107 is a photodiode that photoelectrically converts the combined wave combined by the coupler 106 into an analog optical signal. For the coupler 106 and the photodetector 107, for example, a heterodyne detector, a homodyne detector, or a balance photodiode (BPD) can be used.

[0045] The switch control circuit 108 outputs a control signal to the switch array 104 for turning on and off each switch element of the switch array 104 .

[0046] 1 , the lens 200 will be described. The lens 200 focuses the first light L1 emitted from the antenna array 105 of the optical device 100 onto the diffraction grating 152. The collimator 19 also focuses the third light L3, which is reflected by the object 1000 and transmitted through the diffraction grating 152, onto the antenna array 105.

[0047] Lens 200 may be a spherical lens or an aspherical lens. In the first structural example of lens 200 shown in Fig. 1, one lens is disposed between optical device 100 and diffraction grating 300, but the number of lenses is not limited to one.

[0048] Fig. 8A is a plan view showing a second example structure of the lens. Fig. 8B is a cross-sectional view showing the second example structure of the lens. In the lens 200b shown in Figs. 8A and 8B, multiple lenses are arranged in a straight line along the traveling direction of the first light L1. With this lens 200b, the number of lenses is increased compared to the first example structure, and therefore aberration is reduced. As a result, light receiving efficiency is improved.

[0049] FIG. 9A is a plan view showing a third example structure of a lens. FIG. 9B is a cross-sectional view showing the third example structure of a lens. Lens 200c shown in FIGS. 9A and 9B is composed of a main body 201 and at least one metalens having a diffraction grating pattern 202. As shown in FIG. 9A, diffraction grating pattern 202 is a pattern that spreads radially from the center of main body 201. As shown in FIG. 9B, the thickness t of the diffraction grating formed in main body 201 is designed to be several tens of nanometers to several micrometers. In lens 200c, the diffraction grating pattern 202 quantizes the phase distribution of incident light, i.e., first light L1.

[0050] 1 , the diffraction grating 300 will be described. The diffraction grating 300 converts the first light L1 transmitted through the lens 200 into a plurality of diffracted light beams L11. The plurality of diffracted light beams L11 include, for example, a diffracted light beam having a wavelength λ component of the first light L1, a diffracted light beam having a wavelength (λ+Δλ) component longer than the wavelength λ, and a diffracted light beam having a wavelength (λ−Δλ) component shorter than the wavelength λ.

[0051] 10A is a plan view showing a first example structure of the diffraction grating. FIG. 10B is a cross-sectional view showing the first example structure of the diffraction grating. The diffraction grating 300a shown in FIGS. 10A and 10B has a blade-like uneven shape. The height h of the convex portions of this uneven shape is designed to be on the order of μm. The diffraction grating 300a diffracts the first light L1 in accordance with the wavelength λ, incident angle, and diffraction pitch of the first light L1.

[0052] 11A is a plan view showing a second example structure of the diffraction grating. FIG. 11B is a cross-sectional view showing the second example structure of the diffraction grating. The diffraction grating 300b shown in FIGS. 11A and 11B has a single-step uneven shape. This uneven shape may be columnar, as shown in FIG. 11B, or may be multi-step blade-like. The height h of the protrusions is designed to be on the order of μm.

[0053] The diffraction grating 300b configured as above also diffracts the first light L1 in accordance with the wavelength λ, the incident angle, and the diffraction pitch of the first light L1.

[0054] FIG. 12A is a plan view showing a third example structure of the diffraction grating. FIG. 12B is a cross-sectional view showing the third example structure of the diffraction grating. The diffraction grating 300c shown in FIGS. 12A and 12B is composed of a main body 301 and at least one metagrating having a diffraction grating pattern 302. As shown in FIG. 12A, the diffraction grating pattern 302 is a square pattern. As shown in FIG. 12B, the thickness t of the diffraction grating pattern 302 formed in the main body 201 is designed to be on the order of nanometers.

[0055] In diffraction grating 300c, the thickness t of diffraction grating pattern 302 is smaller than the height of the concave-convex shapes of diffraction gratings 300a and 300b. This reduces unwanted light components due to wall reflection. As a result, the diffraction efficiency of diffraction grating 300c is higher than the diffraction efficiency of each of diffraction gratings 300a and 300b.

[0056] Fig. 13A is an enlarged view of a diffraction grating pattern of a diffraction grating according to a third structural example. In the diffraction grating 300c shown in Fig. 13A, diffraction gratings each having a circular planar shape are arranged in one direction at equal intervals of a pitch p. In addition, in the diffraction grating rows of the diffraction grating pattern 302, the diameter of the diffraction gratings increases in stages.

[0057] 13B is an enlarged view of the diffraction grating pattern of the diffraction grating according to the fourth structural example. In the diffraction grating 300d shown in FIG. 13B, the diffraction grating pattern 302 is a hexagonal arrangement pattern. Specifically, in two adjacent diffraction grating rows in the vertical direction, the circular diffraction gratings are arranged with a half-pitch (½p) offset. This hexagonal arrangement pattern increases the packing factor of the diffraction grating, thereby improving the phase distribution reproducibility. This improves the diffraction efficiency.

[0058] In the first to fourth structural examples described above, the planar shape of the diffraction grating is circular. However, the planar shape of the diffraction grating is not limited to a circular shape. Other examples of the planar shape of the diffraction grating will be described below.

[0059] Fig. 14A is a plan view showing a fifth structural example of a diffraction grating. The planar shape of diffraction grating 300e shown in Fig. 14A is quadrangular. The planar shape of diffraction grating 300f is rhombic. The planar shape of diffraction grating 300g is hexagonal. Note that in the fourth structural example, the planar shapes of the diffraction gratings are not limited to these shapes and may be other polygonal shapes.

[0060] 14B is a plan view showing a sixth example structure of a diffraction grating. The planar shape of the diffraction grating 300h shown in FIG. 14B is a cross. Note that the shape of the diffraction grating is not limited to geometric shapes such as a polygon and a cross, and may be a free-form shape.

[0061] When the planar shape of the diffraction grating is circular, it can be designed independently of the polarization of the first light L1, whereas when the planar shape of the diffraction grating is a polygonal or cross-shaped shape with corners, it can be designed depending on the polarization of the first light L1.

[0062] 15A is a plan view showing a seventh structural example of a diffraction grating. In the diffraction grating 300i shown in FIG. 15A, a plurality of slits 303 extend in the vertical direction. The slits 303 formed in the central region of the diffraction grating 300i have the largest spacing d1 between them, and in regions other than the central region, the slits 303 are formed at spacing d2.

[0063] Figure 15B is a graph showing the relationship between position and phase in a cross section taken along the cutting line A1-A1 in Figure 15A. In Figure 15B, the horizontal axis represents the horizontal position in the cross section taken along the cutting line A1-A1, and the vertical axis represents the phase. When the diffraction grating 300i is divided by the slits 303 as shown in Figure 15A, the phase distribution is concentrated toward the central region of the diffraction grating 300i.

[0064] 16A is a plan view showing an eighth example structure of a diffraction grating. In the diffraction grating 300j shown in FIG. 16A, a plurality of slits 303 extend in the horizontal direction. The slits 303 formed in the central region of the diffraction grating 300j have the largest spacing d1 between them, and in regions other than the central region, the slits 303 are formed at spacing d2.

[0065] Figure 16B is a graph showing the relationship between position and phase in a cross section taken along the cutting line A2-A2 in Figure 16A. In Figure 16B, the horizontal axis represents the horizontal position in the cross section taken along the cutting line A2-A2, and the vertical axis represents the phase. When diffraction grating 300j is divided by slits 303 as shown in Figure 16A, the phase distribution is concentrated toward the central region of diffraction grating 300j.

[0066] Fig. 17A is a plan view showing a ninth structural example of a diffraction grating. In a diffraction grating 300k shown in Fig. 18A, diamond-shaped slits 303 are arranged in multiple layers. The slits 303 are formed at intervals d.

[0067] Figure 17B is a graph showing the relationship between position and phase in a cross section taken along the cutting line A3-A3 in Figure 17A. In Figure 17B, the horizontal axis represents the horizontal position in the cross section taken along the cutting line A3-A3, and the vertical axis represents the phase. When diffraction grating 300k is divided by slits 303 as shown in Figure 17A, the phase distribution is concentrated toward the central region of diffraction grating 300k.

[0068] As described above, when the diffraction grating 300 is divided by the slits 303, the distribution of projection spots indicating beam irradiation points where the first light L1 diffracted by the diffraction grating 300 is irradiated on the object 1000 changes. Here, the projection spot distribution of the first light L1 will be described.

[0069] 18A is a diagram showing a projection spot distribution when the first light L1 is diffracted by a diffraction grating divided by equally spaced slits. In the projection spot distribution 310a shown in FIG. 18A, the projection spots of the first light L1 are distributed in a square arrangement.

[0070] 18B is a diagram showing a projection spot distribution when the first light L1 is diffracted by a diffraction grating divided by slits according to the seventh structural example. In the projection spot distribution 310b shown in FIG. 18B, the projection spots of the first light L1 are distributed so as to be dense in a vertically elongated central region 401 of the projection region.

[0071] 18C is a diagram showing a projection spot distribution when the first light L1 is diffracted by a diffraction grating divided by slits according to the eighth structural example. In the projection spot distribution 310c shown in FIG. 18C, the projection spots of the first light L1 are distributed so as to be dense in a horizontally elongated central region 402 of the projection region.

[0072] 18D is a diagram showing a projection spot distribution when the first light L1 is diffracted by a diffraction grating divided by slits according to the ninth structural example. In the projection spot distribution 310d shown in FIG. 18D, the projection spots of the first light L1 are distributed so as to be dense in a central region 403 of the cross-shaped projection region.

[0073] According to the first embodiment described above, the diffraction grating 300 converts the first light L1 emitted from the optical device 100 into a plurality of diffracted light beams L11. Therefore, the number of beam irradiation points increases without increasing the physical size of the optical device. Therefore, it is possible to improve the resolution.

[0074] (First Modification) Fig. 19 is a plan view of an optical measurement apparatus according to a first modification. In an optical measurement apparatus 1a according to the first modification, a plurality of optical devices 100, a plurality of lenses 200, and a plurality of diffraction gratings 300 are arranged in a row. Note that the optical measurement apparatus 1a may have a single diffraction grating 300. In this case, one diffraction grating 300 is shared by the plurality of optical devices 100 and the plurality of lenses 200.

[0075] According to this modification, similar to the first embodiment, the diffraction grating 300 converts the first light L1 into a plurality of diffracted light L11, thereby making it possible to increase the resolution without increasing the physical size of the optical device.

[0076] (Second Modification) Fig. 20 is a plan view of an optical measurement apparatus according to a second modification. In an optical measurement apparatus 1b according to the second modification, a plurality of optical devices 100, a plurality of lenses 200, and a plurality of diffraction gratings 300 are arranged in a matrix. Note that the optical measurement apparatus 1b may have a single diffraction grating 300. In this case, one diffraction grating 300 is shared by the plurality of optical devices 100 and the plurality of lenses 200.

[0077] According to this modification, similar to the first embodiment, the diffraction grating 300 converts the first light L1 into a plurality of diffracted light L11, thereby making it possible to increase the resolution without increasing the physical size of the optical device.

[0078] 21 is a cross-sectional view of an optical measurement device according to a third modification. In an optical measurement device 1c according to the third modification, a diffraction grating 300 is disposed between an optical device 100 and a lens 200. That is, in this modification, the positional relationship between the optical device 100 and the lens 200 is opposite to that in the first embodiment.

[0079] In the optical measurement apparatus 1c according to this modification, the first light L1 emitted from the optical device 100 is converted into a plurality of diffracted light beams by the diffraction grating 300. Subsequently, the plurality of diffracted light beams are condensed by the lens 200 toward the object 1000.

[0080] According to this modification, similar to the first embodiment, the diffraction grating 300 converts the first light L1 into a plurality of diffracted light L11, thereby making it possible to increase the resolution without increasing the physical size of the optical device.

[0081] 22 is a cross-sectional view of an optical measurement device according to a fourth modification. In an optical measurement device 1d according to the fourth modification, a diffraction grating 300 is disposed between a first lens 210 and a second lens 211. The structures of the first lens 210 and the second lens 211 are similar to those of the lens 200 described in the first embodiment, and therefore description thereof will be omitted.

[0082] In the optical measurement apparatus 1d according to this modification, the first light L1 emitted from the optical device 100 is collected by the first lens 210 and enters the diffraction grating 300. Next, the first light L1 is converted into a plurality of diffracted light beams by the diffraction grating 300. Finally, the plurality of diffracted light beams are collected by the second lens 211 and are irradiated toward the object 1000.

[0083] According to this modification, similar to the first embodiment, the diffraction grating 300 converts the first light L1 into a plurality of diffracted light L11, thereby making it possible to increase the resolution without increasing the physical size of the optical device.

[0084] 23 is a cross-sectional view of an optical measurement device according to Modification 5. In the optical measurement device 1e according to Modification 5, the first lens 210 described in Modification 4 is divided into a first portion 210a and a second portion 210b.

[0085] In the optical measurement apparatus 1e according to this modification, the first light L1 emitted from the optical device 100 is collected by the first portion 210a and the second portion 210b, respectively, and then incident on the diffraction grating 300. Subsequently, the first light L1 is converted into a plurality of diffracted light beams by the diffraction grating 300. Finally, the plurality of diffracted light beams are collected by the second lens 211 and then irradiated toward the object 1000.

[0086] According to this modification, similar to the first embodiment, the diffraction grating 300 converts the first light L1 into a plurality of diffracted light L11, thereby making it possible to increase the resolution without increasing the physical size of the optical device.

[0087] 24 is a cross-sectional view of an optical measurement device according to a second embodiment. The same optical elements as those in the optical measurement device 1 according to the first embodiment described above are denoted by the same reference numerals, and duplicated explanations will be omitted.

[0088] The optical measurement apparatus 2 according to this embodiment further includes a microlens array 400 in addition to the optical device 100 , the lens 200 , and the diffraction grating 300 .

[0089] The microlens array 400 is disposed between the optical device 100 and the lens 200. A plurality of microlenses 401 are arranged in an array in the microlens array 400. Each of the plurality of microlenses 401 converts the first light L1 emitted from the optical device 100 into a parallel light. The parallel light passes through the lens 200 and is converted into a plurality of diffracted light beams by the diffraction grating 300.

[0090] Therefore, according to this embodiment, similar to the first embodiment, the diffraction grating 300 converts the first light L1 into multiple diffracted lights L11, making it possible to increase the resolution without increasing the physical size of the optical device.

[0091] Furthermore, according to the present embodiment, the microlens array 400 functions as a collimator of the first light L1, which suppresses diffusion of the first light L1 and improves the collimation characteristics of the first light L1, thereby enabling the lens 200 to be made low-profile.

[0092] 25 is a cross-sectional view of an optical measurement device according to a sixth modification. In an optical measurement device 2a according to this modification, a microlens array 410 is formed on an optical device 100 by a semiconductor process. The microlens array 410 according to this modification has a plurality of microlenses 411 arranged in an array. The plurality of microlenses 411 converts the first light L1 into parallel light. The parallel light then passes through a lens 200 and is converted into a plurality of diffracted light beams by a diffraction grating 300.

[0093] Therefore, according to this modified example, similar to the second embodiment, the diffraction grating 300 converts the first light L1 into multiple diffracted lights L11, making it possible to increase the resolution without increasing the physical size of the optical device.

[0094] In addition, in this modification, the microlens array 410 suppresses diffusion of the first light L1 and improves the collimation characteristics of the first light L1, thereby enabling a reduction in the height of the lens 200. Furthermore, in this modification, the microlens array 410 is provided integrally with the optical device 100. Therefore, compared to the second embodiment, the accuracy of alignment of the microlenses 411 is improved.

[0095] 26 is a cross-sectional view of an optical measurement device according to a seventh modification. The optical measurement device 2b according to this modification includes the microlens array 400 described in the fifth modification and the microlens array 410 described in the sixth modification. Therefore, the first light L1 emitted from the optical device 100 is collimated sequentially by the microlens 411 and the microlens 401. The collimated first light L1 passes through the lens 200 and is converted into a plurality of diffracted light beams by the diffraction grating 300.

[0096] Therefore, according to this modified example, similar to the second embodiment, the diffraction grating 300 converts the first light L1 into multiple diffracted lights L11, making it possible to increase the resolution without increasing the physical size of the optical device.

[0097] In this modification, the microlens array 400 and the microlens array 410 further suppress diffusion of the first light L1, thereby further improving the collimation characteristics of the first light L1. This makes it possible to further reduce the height of the lens 200. Furthermore, in this modification, the microlens array 410 is also provided integrally with the optical device 100, thereby improving the accuracy of alignment of the microlenses 411 compared to the second embodiment.

[0098] 27 is a cross-sectional view of an optical measurement device according to a third embodiment. The same optical elements as those in the optical measurement device 1 according to the first embodiment described above are denoted by the same reference numerals, and duplicated explanations will be omitted.

[0099] The optical measurement apparatus 3 according to this embodiment includes an optical device 100, a first lens 210, a second lens 211, and a diffraction grating 300. The first lens 210 is disposed between the optical device 100 and the diffraction grating 300. The second lens 211 is disposed in front of the diffraction grating 300 in the traveling direction of the diffracted light L11. However, the second lens 211 is not an essential optical element and may not be provided in the optical measurement apparatus 3.

[0100] In the optical measurement apparatus 3 according to this embodiment, the first light L1 emitted from the optical device 100 passes through the first lens 210 and is incident on the diffraction grating 300. The diffraction grating 300 according to this embodiment is a reflective diffraction grating. Therefore, the first light L1 is reflected by the diffraction grating 300 and converted into a plurality of diffracted light beams L11. Each diffracted light beam L11 passes through the second lens 211 and is irradiated toward the object 1000.

[0101] According to the present embodiment described above, similarly to the first embodiment, the diffraction grating 300 converts the first light L1 into a plurality of diffracted light L11, thereby making it possible to increase the resolution without increasing the physical size of the optical device 100.

[0102] Furthermore, in this embodiment, the diffraction grating 300 is a reflective diffraction grating, so that the focal length can be increased and the NA (Numerical Aperture) can be increased.

[0103] 28 is a cross-sectional view of an optical measurement device according to a fourth embodiment. The same optical elements as those in the optical measurement device 1 according to the first embodiment described above are denoted by the same reference numerals, and duplicated explanations will be omitted.

[0104] The optical measurement apparatus 4 according to this embodiment further includes a movable mirror 500 in addition to the optical device 100, the lens 200, and the diffraction grating 300. The movable mirror 500 is disposed in front of the diffraction grating 300 in the traveling direction of the diffracted light L11.

[0105] The diffracted light L11 is reflected by the movable mirror 500. This reflected light L12 is irradiated toward the object 1000. At this time, when the movable mirror 500 moves, the incident angle of the diffracted light L11 changes. As a result, the traveling direction of the reflected light L12 also changes.

[0106] According to the present embodiment described above, similarly to the first embodiment, the diffraction grating 300 converts the first light L1 into a plurality of diffracted light beams L11, thereby enabling an increase in resolution without increasing the physical size of the optical device 100. Furthermore, in this embodiment, a movable mirror 500 capable of adjusting the angle of incidence of the diffracted light beam L11 is provided. By adjusting the angle of incidence of the diffracted light beam L11, the traveling direction of the reflected light beam L12 can be set. This allows a larger amount of reflected light beam L12 to be irradiated toward the object 1000, thereby enabling an even greater increase in resolution.

[0107] (Fifth embodiment) Fig. 29A is a plan view of an optical measurement device according to a fifth embodiment. Fig. 29B is a cross-sectional view of the optical measurement device according to the fifth embodiment. In Fig. 29A and Fig. 29B, the same optical elements as those in the optical measurement device 1 according to the first embodiment described above are denoted by the same reference numerals, and duplicated explanations will be omitted.

[0108] The optical measurement apparatus 5 according to this embodiment has an optical device 100 and an optical component 600. The optical component 600 is disposed on the optical device 100, as shown in Fig. 29B.

[0109] The optical component 600 has a lens portion 601 and a diffraction grating portion 602. The lens portion 601 has a function equivalent to that of the lens 200 described in the first embodiment. The diffraction grating portion 602 has a function equivalent to that of the diffraction grating 300 described in the first embodiment. In this embodiment, the diffraction grating portions 602 are arranged radially from the center of the lens portion 601.

[0110] In the optical measurement apparatus 5 configured as described above, the first light L1 emitted from the optical device 100 is incident on the optical component 600. In the optical component 600, the first light L1 passes through the lens portion 601 and is converted into a plurality of diffracted light beams by the diffraction grating portion 602.

[0111] Therefore, according to this embodiment, it is possible to increase the resolution without increasing the physical size of the optical device 100, as in the first embodiment. Furthermore, in this embodiment, the optical component 600 functions as both a lens and a diffraction grating. In other words, in this embodiment, the lens 200 and the diffraction grating 300 are integrated as the optical component 600. Therefore, the number of parts is reduced compared to the first embodiment, making it possible to make the device thinner and reduce costs.

[0112] <Application to a Mobile Body> The technology according to the present disclosure (the present technology) can be applied to various products. For example, the technology according to the present disclosure may be realized as a device mounted on any type of mobile body, such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, personal mobility, an airplane, a drone, a ship, or a robot.

[0113] FIG. 30 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile object control system to which the technology according to the present disclosure can be applied.

[0114] The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in Fig. 30 , the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an outside-vehicle information detection unit 12030, an inside-vehicle information detection unit 12040, and an integrated control unit 12050. Also shown as functional components of the integrated control unit 12050 are a microcomputer 12051, an audio / video output unit 12052, and an in-vehicle network I / F (interface) 12053.

[0115] The drivetrain control unit 12010 controls the operation of devices related to the drivetrain of the vehicle in accordance with various programs. For example, the drivetrain control unit 12010 functions as a control device for a drive force generating device for generating a drive force of the vehicle, such as an internal combustion engine or a drive motor, a drive force transmission mechanism for transmitting the drive force to the wheels, a steering mechanism for adjusting the steering angle of the vehicle, and a braking device for generating a braking force of the vehicle.

[0116] The body system control unit 12020 controls the operation of various devices equipped in the vehicle body according to various programs. For example, the body system control unit 12020 functions as a control device for a keyless entry system, a smart key system, a power window device, or various lamps such as headlamps, backup lamps, brake lamps, turn signals, and fog lamps. In this case, radio waves transmitted from a portable device that serves as a key or signals from various switches can be input to the body system control unit 12020. The body system control unit 12020 receives these radio waves or signals and controls the vehicle's door lock device, power window device, lamps, etc.

[0117] The outside-vehicle information detection unit 12030 detects information outside the vehicle equipped with the vehicle control system 12000. For example, an imaging unit 12031 is connected to the outside-vehicle information detection unit 12030. The outside-vehicle information detection unit 12030 causes the imaging unit 12031 to capture images outside the vehicle and receives the captured images. The outside-vehicle information detection unit 12030 may perform object detection processing or distance detection processing for people, cars, obstacles, signs, characters on the road surface, etc. based on the received images.

[0118] The imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal corresponding to the amount of light received. The imaging unit 12031 can output the electrical signal as an image or as distance measurement information. The light received by the imaging unit 12031 may be visible light or invisible light such as infrared light.

[0119] The in-vehicle information detection unit 12040 detects information inside the vehicle. For example, a driver state detection unit 12041 that detects the state of the driver is connected to the in-vehicle information detection unit 12040. The driver state detection unit 12041 includes, for example, a camera that captures an image of the driver, and the in-vehicle information detection unit 12040 may calculate the degree of fatigue or concentration of the driver based on the detection information input from the driver state detection unit 12041, or may determine whether the driver is dozing off.

[0120] The microcomputer 12051 can calculate control target values ​​for the driving force generating device, steering mechanism, or braking device based on the information inside and outside the vehicle acquired by the outside-vehicle information detection unit 12030 or the inside-vehicle information detection unit 12040, and output control commands to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control aimed at realizing the functions of an ADAS (Advanced Driver Assistance System), including vehicle collision avoidance or impact mitigation, following driving based on the inter-vehicle distance, vehicle speed maintenance driving, vehicle collision warning, vehicle lane departure warning, etc.

[0121] In addition, the microcomputer 12051 can perform cooperative control for the purpose of autonomous driving, which allows the vehicle to travel autonomously without relying on driver operation, by controlling the driving force generating device, steering mechanism, braking device, etc. based on information about the surroundings of the vehicle obtained by the outside vehicle information detection unit 12030 or the inside vehicle information detection unit 12040.

[0122] Furthermore, the microcomputer 12051 can output a control command to the body system control unit 12020 based on the information outside the vehicle acquired by the outside information detection unit 12030. For example, the microcomputer 12051 can control the headlamps according to the position of a preceding vehicle or an oncoming vehicle detected by the outside information detection unit 12030, and perform cooperative control aimed at preventing glare, such as switching from high beams to low beams.

[0123] The audio / video output unit 12052 transmits at least one of audio and video output signals to an output device capable of visually or audibly notifying information to vehicle occupants or the outside of the vehicle. In the example of Fig. 30, the output devices are exemplified by an audio speaker 12061, a display unit 12062, and an instrument panel 12063. The display unit 12062 may include, for example, at least one of an on-board display and a head-up display.

[0124] FIG. 31 is a diagram showing an example of the installation position of the imaging unit 12031.

[0125] In FIG. 31 , a vehicle 12100 has imaging units 12101, 12102, 12103, 12104, and 12105 as the imaging unit 12031.

[0126] The imaging units 12101, 12102, 12103, 12104, and 12105 are provided, for example, at positions such as the front nose, side mirrors, rear bumper, back door, and the top of the windshield inside the vehicle cabin of the vehicle 12100. The imaging unit 12101 provided on the front nose and the imaging unit 12105 provided on the top of the windshield inside the vehicle cabin mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 provided on the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 provided on the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The forward images acquired by the imaging units 12101 and 12105 are mainly used to detect preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, lanes, etc.

[0127] 31 shows an example of the imaging ranges of the imaging units 12101 to 12104. Imaging range 12111 indicates the imaging range of the imaging unit 12101 provided on the front nose, imaging ranges 12112 and 12113 indicate the imaging ranges of the imaging units 12102 and 12103 provided on the side mirrors, respectively, and imaging range 12114 indicates the imaging range of the imaging unit 12104 provided on the rear bumper or back door. For example, by overlaying the image data captured by the imaging units 12101 to 12104, an overhead image of the vehicle 12100 viewed from above can be obtained.

[0128] At least one of the image capturing units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the image capturing units 12101 to 12104 may be a stereo camera made up of multiple image capturing elements, or may be an image capturing element having pixels for phase difference detection.

[0129] For example, based on the distance information obtained from the imaging units 12101 to 12104, the microcomputer 12051 can calculate the distance to each three-dimensional object within the imaging ranges 12111 to 12114 and the change in this distance over time (relative speed with respect to the vehicle 12100), thereby extracting as a preceding vehicle, in particular, the three-dimensional object that is the closest three-dimensional object on the path of the vehicle 12100 and traveling in approximately the same direction as the vehicle 12100 at a predetermined speed (e.g., 0 km / h or higher). Furthermore, the microcomputer 12051 can set a vehicle-to-vehicle distance to be maintained in advance in front of the preceding vehicle, and perform automatic braking control (including follow-up stop control), automatic acceleration control (including follow-up start control), etc. In this way, cooperative control can be performed for the purpose of autonomous driving, which runs autonomously without relying on driver operation.

[0130] For example, the microcomputer 12051 classifies and extracts three-dimensional object data regarding three-dimensional objects into two-wheeled vehicles, ordinary vehicles, large vehicles, pedestrians, utility poles, and other three-dimensional objects based on distance information obtained from the imaging units 12101 to 12104, and can use the data for automatic obstacle avoidance. For example, the microcomputer 12051 distinguishes obstacles around the vehicle 12100 into obstacles that are visible to the driver of the vehicle 12100 and obstacles that are difficult to see. The microcomputer 12051 determines a collision risk that indicates the risk of collision with each obstacle, and when the collision risk is equal to or greater than a set value and a collision is possible, the microcomputer 12051 can provide driving assistance for collision avoidance by outputting an alarm to the driver via the audio speaker 12061 or the display unit 12062, or by performing forced deceleration or avoidance steering via the drive system control unit 12010.

[0131] At least one of the image capturing units 12101 to 12104 may be an infrared camera that detects infrared rays. For example, the microcomputer 12051 can recognize a pedestrian by determining whether a pedestrian is present in the images captured by the image capturing units 12101 to 12104. Such pedestrian recognition is performed, for example, by extracting feature points from the images captured by the image capturing units 12101 to 12104 as infrared cameras and performing pattern matching on a series of feature points that indicate the outline of an object to determine whether the object is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the images captured by the image capturing units 12101 to 12104 and recognizes the pedestrian, the audio / image output unit 12052 controls the display unit 12062 to superimpose a rectangular outline on the recognized pedestrian for emphasis. The audio / image output unit 12052 may also control the display unit 12062 to display an icon or the like indicating the pedestrian at a desired position.

[0132] An example of a vehicle control system to which the technology according to the present disclosure can be applied has been described above. The technology according to the present disclosure can be applied to, for example, the image capturing unit 12031 among the components described above. Applying the technology according to the present disclosure to the image capturing unit 12031 can improve distance measurement accuracy. As a result, the performance of the vehicle 12100 can be improved.

[0133] The present technology can be configured as follows:

[0134] (1) An optical measurement device comprising: an optical device that emits wavelength-tunable light; a lens through which the light passes; and a diffraction grating that converts the light into a plurality of diffracted beams.

[0135] (2) The optical measurement device according to (1), wherein the plurality of lenses are arranged in a straight line along the traveling direction of the light.

[0136] (3) The optical measurement device according to (1) or (2), wherein the lens has a diffraction grating pattern that radiates from the center of the body.

[0137] (4) The optical measurement device according to any one of (1) to (3), wherein the diffraction grating has a blade-like concave-convex shape.

[0138] (5) The optical measurement device according to any one of (1) to (4), wherein the diffraction grating has a columnar concave-convex shape.

[0139] (6) The optical measurement device according to any one of (1) to (5), wherein the diffraction grating pattern is a square arrangement.

[0140] (7) The optical measurement device according to any one of (1) to (5), wherein the diffraction grating pattern is a hexagonal arrangement.

[0141] (8) The optical measurement device according to any one of (1) to (7), wherein the planar shape of the diffraction grating is circular, polygonal, or cross-shaped.

[0142] (9) The optical measurement device according to (1), wherein the diffraction grating has a plurality of slits, and the spacing between the slits formed in the central region of the diffraction grating is the largest.

[0143] (10) The optical measurement device according to (1), wherein the diffraction grating has a plurality of diamond-shaped slits arranged in a multiplicity.

[0144] (11) The optical measurement device according to any one of (1) to (10), wherein the plurality of lenses and the plurality of diffraction gratings are arranged in a line.

[0145] (12) The optical measurement device according to any one of (1) to (10), wherein the plurality of lenses and the plurality of diffraction gratings are arranged in a matrix.

[0146] (13) The optical measurement device according to any one of (1) to (12), wherein the lens is disposed between the optical device and the diffraction grating.

[0147] (14) The optical measurement apparatus according to any one of (1) to (12), wherein the diffraction grating is disposed between the optical device and the lens.

[0148] (15) The optical measurement device according to (1), wherein the lens includes: a first lens disposed between the optical device and the diffraction grating; and a second lens disposed in front of the diffraction grating in the direction of propagation of the diffracted light.

[0149] (16) The optical measurement device according to (15), wherein the first lens is divided into a first portion and a second portion.

[0150] (17) The optical measurement device according to (1), further comprising a microlens array disposed between the optical device and the lens.

[0151] (18) The optical measurement instrument according to (17), wherein the microlens array is integrated with the optical device.

[0152] (19) The optical measurement device according to (15), wherein the diffraction grating is a reflective diffraction grating.

[0153] (20) The optical measurement device according to (1), wherein the lens and the diffraction grating are integrated.

[0154] 1 to 5: Optical measurement device 100: Optical device 200: Lens 210: First lens 210a: First portion 220a: Second portion 211: Second lens 300: Diffraction grating 303: Slit 400: Microlens array 410: Microlens array

Claims

1. An optical measurement apparatus comprising: an optical device that emits light of a tunable wavelength; a lens through which the light passes; and a diffraction grating that converts the light into a plurality of diffracted beams.

2. The optical measurement device according to claim 1, wherein the plurality of lenses are arranged in a straight line along the direction in which the light travels.

3. The optical metrology device of claim 1, wherein said lens has a diffraction grating pattern radiating from the center of the body.

4. The optical measurement device according to claim 1, wherein said diffraction grating has a blade-like uneven shape.

5. The optical measurement device according to claim 1, wherein said diffraction grating has a columnar uneven shape.

6. The optical measurement device according to claim 1, wherein the diffraction grating pattern is a square arrangement.

7. The optical metrology device of claim 1, wherein the diffraction grating pattern is a hexagonal arrangement.

8. The optical measurement device according to claim 1, wherein the planar shape of said diffraction grating is circular, polygonal, or cross-shaped.

9. The optical measurement device according to claim 1, wherein the diffraction grating has a plurality of slits, and the spacing between the slits formed in the central region of the diffraction grating is the largest.

10. The optical measurement device according to claim 1, wherein said diffraction grating has a plurality of diamond-shaped slits arranged in a multiplicity.

11. The optical metrology device of claim 1, wherein a plurality of said lenses and a plurality of said diffraction gratings are aligned in a row.

12. The optical measurement device according to claim 1, wherein a plurality of said lenses and a plurality of said diffraction gratings are arranged in a matrix.

13. The optical metrology apparatus of claim 1, wherein the lens is positioned between the optical device and the diffraction grating.

14. The optical metrology instrument of claim 1, wherein the diffraction grating is disposed between the optical device and the lens.

15. The optical measurement device according to claim 1, wherein the lens comprises: a first lens disposed between the optical device and the diffraction grating; and a second lens disposed in front of the diffraction grating in the direction of propagation of the diffracted light.

16. The optical metrology device of claim 15, wherein the first lens is divided into a first portion and a second portion.

17. The optical metrology apparatus of claim 1, further comprising a microlens array disposed between said optical device and said lens.

18. The optical metrology instrument of claim 17, wherein the microlens array is integral with the optical device.

19. The optical metrology device of claim 15, wherein the diffraction grating is a reflective diffraction grating.

20. The optical measurement device of claim 1, wherein the lens and the diffraction grating are integrated.

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