Optical system device

Abstract

The purpose of the invention is to provide an optical system device capable of improving an SN ratio by reducing noise due to background light such as multipath.　Provided is an optical system device comprising: a light irradiation means 10 capable of irradiating with dot-like or line-like light by switching to different positions of an object 9; an imaging means 20 for detecting information on the received light; and a calculation means 30 for switching the position of the light radiated by the light irradiation means 10 and reducing noise due to multipath or the like from the information on the light, which has been detected by the imaging means 20, on the basis of the information.

Description

optical system equipment

[0001] The present invention relates to an optical system device.

[0002] Three-dimensional measurement optical systems using the time-of-flight (TOF) method are being adopted in mobile devices, automobiles, robots, etc. This system measures the distance to an object from the time it takes for light irradiated from a light source onto the object to be reflected and returned. If the light from the light source is irradiated uniformly over a predetermined area of ​​the object, the distance at each irradiated point can be measured, and the three-dimensional structure of the object can be detected.

[0003] The optical system device comprises a light irradiation unit that irradiates light onto an object, an imaging unit that detects light reflected from each point on the object, and a calculation unit that calculates the distance to the object from the signal received by the imaging unit (for example, Patent Document 1).

[0004] Patent 7418050

[0005] However, TOF technology has a problem in that noise such as background light due to multipath occurs. Multipath is a phenomenon in which transmitted light travels multiple paths before reaching its destination. Particularly in indoor environments or complex terrain, light often reflects off walls and other objects, taking multiple paths. As a result, if the received light contains noise such as background light due to multipath, the signal-to-noise ratio decreases, making accurate distance measurement difficult.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an optical system that can reduce the influence of noise caused by background light such as multipath light and can perform accurate distance measurement.

[0007] In order to achieve the above object, the optical system device of the present invention is characterized by comprising a light irradiation means capable of switching light irradiation to different positions, an imaging means for detecting information about the received light, and a calculation means for switching the position of light irradiated by the light irradiation means and reducing noise from the information about the light detected by the imaging means based on the information.

[0008] The light irradiation means includes an optical element in which lenses that transmit light of wavelength λ are periodically arranged, a plurality of irradiation units having light sources that irradiate the plurality of lenses with light of wavelength λ, and a control unit that controls lighting of each of the irradiation units, wherein m and n are natural numbers of 1 or more, and the focal length of the cross-sectional shape of the lens perpendicular to the y direction is f １ , the focal length of the cross-sectional shape perpendicular to the x direction is f ２ , the size of the pitch of the lens in the x direction is P １ , the size of the pitch in the y direction is P ２ Then, the distance L between the irradiation unit and the first focal plane of the lens is １ , distance L to the second focal plane ２ is expressed by the following formula 1 and formula 2 It is preferable to satisfy the following.

[0009] The irradiation units may include different types of irradiation units in which, when the positions of the light sources relative to the lenses are superimposed on one lens for each irradiation unit, the positions of the aggregated apparent light sources are different from each other.

[0010] The light sources included in the same irradiation unit are a plurality of light sources that are periodically arranged, and the pitch of the light sources in the x direction is equal to the lens pitch P １ and the pitch in the y direction is the lens pitch P ２ It may be a natural number multiple or a reciprocal multiple of a natural number.

[0011] In addition, the distance L １ and L ２ is expressed by the following formula 3 and formula 4. It is preferable to satisfy the following.

[0012] The light irradiating means has lenses that transmit light of wavelength λ at a pitch P ｘ , pitch P in the y direction perpendicular to the x direction ｙ and a light source that irradiates a plurality of the lenses with light of wavelength λ is arranged at a pitch Q in the x direction. ｘ , pitch Q in the y direction ｙand a control unit that controls lighting of each of the irradiation units, where j, k, m, and n are natural numbers of 1 or more, and the focal length to a first focus of the cross-sectional shape of the lens perpendicular to the y direction is f １ , the focal length to the second focus according to the cross-sectional shape perpendicular to the x direction is f ２ , a plane perpendicular to the z direction including the first focal point is defined as a first focal plane, and a plane perpendicular to the z direction including the second focal point is defined as a second focal plane, the distance L between the irradiation unit and the first focal plane of the lens is defined as １ is expressed by the following formula 1 and the pitch of the light sources of the irradiation unit is Q ｘ =jp ｘ or jQ ｘ =P ｘ and the distance L between the irradiation unit and the second focal plane of the lens is ２ is expressed by the following formula 2 does not satisfy, or the pitch of the light source of the irradiation unit is Q ｙ = kP ｙ and kQ ｙ =P ｙ It is preferable that the above condition is not satisfied.

[0013] The light irradiating means has lenses that transmit light of wavelength λ at a pitch P ｘ , pitch P in the y direction perpendicular to the x direction ｙ and a light source that irradiates a plurality of the lenses with light of wavelength λ is arranged at a pitch Q in the y direction. ｙ and a control unit that controls the lighting of each of the irradiation units, wherein k, m, and n are natural numbers of 1 or more, and the focal length to a first focus of the cross-sectional shape of the lens perpendicular to the y direction is f １ , the focal length to the second focus according to the cross-sectional shape perpendicular to the x direction is f ２ , a plane perpendicular to the z direction including the first focal point is defined as a first focal plane, and a plane perpendicular to the z direction including the second focal point is defined as a second focal plane, the distance L between the irradiation unit and the first focal plane of the lens is defined as １ is expressed by the following formula 1 and the distance L between the irradiation unit and the second focal plane of the lens is ２ is expressed by the following formula 2 does not satisfy, or the pitch of the light source of the irradiation unit is Q ｙ = kP ｙ and kQ ｙ =P ｙ It is preferable that the above condition is not satisfied.

[0014] The light irradiation means may also include a plurality of irradiation units, each of which emits a line-shaped light in the x direction and is arranged in a y direction perpendicular to the x direction; a cylindrical lens that converts the light from the irradiation units into light having a different elevation angle with respect to the y direction for each irradiation unit; a diffuser that spreads the light that has passed through the cylindrical lens in the x direction; and a control unit that controls the lighting of each irradiation unit.

[0015] The cylindrical lens may convert the light from each of the irradiation units into parallel light.

[0016] The cylindrical lens may change the light from each of the irradiation units into different light beams with equal elevation angles.

[0017] The optical system device of the present invention can reduce noise caused by background light such as multipath light, thereby improving the signal-to-noise ratio.

[0018] FIG. 1 is a schematic plan view showing an optical system device of the present invention. FIG. 1 is a schematic plan view showing an example of two-dimensional image data. FIG. 2 is a diagram for explaining a noise reduction method. FIG. 3 is a schematic plan view showing another example of two-dimensional image data. FIG. 4 is a diagram for explaining another noise reduction method. (a) A schematic view in the xz plane, (b) A schematic view in the yz plane, and (c) A perspective view showing a lens, showing a light irradiation means according to the present invention. FIG. 1 is a plan view for explaining an overview of an irradiation unit and a light source according to the present invention. FIG. 2 is a plan view for explaining the position of a light source relative to a lens according to the present invention and the position of an apparent light source. FIG. 3 is a plan view for explaining the position of dots formed by transmission through an optical element according to the present invention. (a) A schematic view in the xz plane, (b) A schematic view in the yz plane, and (c) A perspective view showing a lens, showing another light irradiation means according to the present invention. FIG. 4 is a plan view for explaining an overview of an irradiation unit and a light source according to the present invention.

[0019] The optical system device of the present invention will be described below. As shown in FIG. 1, the optical system device of the present invention is mainly composed of a light irradiation means 10, an imaging means 20, and a calculation means 30. This optical system device can be used for the time-of-flight (TOF) method, and can perform three-dimensional measurement of an object 9. In this invention, noise means information unnecessary for measurement due to background light. Background light includes light other than that from the light irradiation means 10 and light due to multipath of the light irradiation means 10.

[0020] The light irradiation means 10 is capable of switching the light irradiation position to irradiate the light. In this way, the light irradiation means 10 can switch the light irradiation position, so that the imaging means 20, which will be described later, can detect and compare information when light is irradiated at multiple positions on the object 9 and information when light is not irradiated. The light irradiation means 10 may be any means that can switch the light irradiation position to irradiate the light. For example, the light irradiation means 10 may be one that irradiates dot-shaped or line-shaped light. Specific light irradiation means 10 will be described later.

[0021] The imaging means 20 detects information about the received light. Specifically, it detects light irradiated from the light irradiation means 10 and reflected by the object 9, and converts information about the position, light intensity, light quantity, etc. into digital data. This allows two-dimensional image data of the light captured by the imaging means 20 to be acquired. Here, two-dimensional image data refers to, for example, light distribution data such as the amount of light and light intensity on an x-y coordinate system. The imaging means 20 may be any device capable of detecting the received light and converting that information into digital data; for example, an existing image sensor such as a CMOS or CCD may be used. Furthermore, the imaging means 20 and the above-mentioned irradiation unit may all be formed on the same semiconductor chip.

[0022] The calculation means 30 switches the position of the light irradiated by the light irradiating means 10 and reduces noise from the information based on the light information detected by the imaging means 20. For example, the calculation means 30 switches the position of the light irradiated by the light irradiating means 10, compares two or more pieces of light information detected by the imaging means 20, calculates information such as the amount of light that becomes noise, and reduces the noise. The more light information compared here, the more accurately the noise can be calculated. Furthermore, the closer the switched light position is, the more accurately the noise can be calculated. By reducing noise in this way, the signal-to-noise ratio can be increased. The calculation means 30 may be any device that can switch the position of the light irradiated by the light irradiating means 10 and reduce noise from the information based on the light information detected by the imaging means 20. For example, a central processing unit (CPU) or a computer including such a CPU can be used.

[0023] Any noise reduction method can be used as long as it can reduce noise from the light information detected by the imaging means 20. For example, noise can be reduced by the following methods (1) to (4). Here, the following explanation will be given using the light irradiation means 10 irradiating dot-shaped light 8A and 8B as shown in FIG. 2 . (1) Light is irradiated by the light irradiation means 10, and the imaging means 20 detects two-dimensional image data A1 with the light intensity shown in FIG. 2(a). The dashed line in FIG. 3(a) is an example of a graph showing the light intensity along the X-X line in FIG. 2(a). (2) Next, the position of the light irradiated by the light irradiation means 10 is switched, and the imaging means 20 similarly detects two-dimensional image data B1 with the light intensity shown in FIG. 2(b). FIG. 2(c) shows two-dimensional image data A1 and B1 superimposed on each other. The dashed line in FIG. 3(a) is an example of a graph showing the light intensity along the X-X line in FIG. 2(b). (3) Next, these two-dimensional image data are compared, and the difference in light intensity at each position is calculated. In other words, the second image data A2 (A1-B1) is calculated by subtracting the light intensity at each position of the two-dimensional image data B1 from the light intensity at each position of the two-dimensional image data A1, and the second image data B2 (B1-A1) is calculated by subtracting the light intensity at each position of the two-dimensional image data B1 from the light intensity at each position of the two-dimensional image data A1. Figures 3(c) and (d) are graphs showing the calculation results on the X-X line. (4) Finally, as shown in Figure 3(e), third image data A3 is created by extracting only the data of the positive portion of the second image data A2, and as shown in Figure 3(f), third image data B3 is created by extracting only the data of the positive portion of the second image data B2. Then, the third image data A3 and the third image data B3 can be made to have a light distribution with reduced noise.

[0024] In the above description, the original two-dimensional image data was of two types, A1 and B1. However, the original two-dimensional image data may be of three or more types. If there are n types of original two-dimensional image data, n-1 types of third image data corresponding to the original two-dimensional image data can be created. In this case, fourth image data may be created by calculating the average light intensity at each position of the n-1 types of third image data, and this data may be used as a light distribution with reduced noise. Specifically, if the original two-dimensional image data is of three types, A1, B1, and C1, the second image data that can be generated from these three types are A21 (A1-B1), A22 (A1-C1), B21 (B1-A1), B22 (B1-C1), C21 (C1-A1), and C22 (C1-B1). Then, the third image data corresponding to A1 will be of two types: A31 (the positive part of A21) and A32 (the positive part of A22), the third image data corresponding to B1 will be of two types: B31 (the positive part of B21) and B32 (the positive part of B22), and the third image data corresponding to C1 will be of two types: C31 (the positive part of C21) and C32 (the positive part of C22). In this case, the average values ​​of the third image data A31 and A32, B31 and B32, and C31 and C32 may be set as the fourth image data A4, B4, and C4, respectively.

[0025] Another method for reducing noise is, for example, the following (1) to (4). Here, the following explanation will be given using the light irradiation means 10 that emits dot-shaped light 8A to 8D as shown in FIG. 4. (1) The position of the light emitted by the light irradiation means 10 is switched, and the light is emitted by the light irradiation means 10, and multiple two-dimensional image data of light intensity are detected by the imaging means 20. FIGS. 4(a) to 4(d) show an example in which four types of two-dimensional image data A1, B1, C1, and D1 are detected. FIG. 4(e) shows two-dimensional image data A1, B1, C1, and D1 superimposed to clearly illustrate the positions of the dots. FIG. 5(1) is an example of a graph showing the light intensity on the X-X line of FIGS. 4(a) to 4(d). (2) Based on the information in (1), positions with and without a light intensity above a predetermined threshold are classified. Then, as shown in FIG. 5(2), the positions where the light intensity is equal to or greater than the predetermined threshold and the corresponding light intensity are determined to be foreground light data A21, B21, C21, and D21 that can be used in the TOF method. Also, as shown in FIG. 5(2), the positions where the light intensity is not equal to or greater than the predetermined threshold and the corresponding light intensity are determined to be background light data A22, B22, C22, and D22. The threshold value may be determined arbitrarily, taking into account information about the surface condition of the object 9 known in advance and information about the measurement environment, such as the ambient brightness. For example, the average light intensity of each 2D image data may be used as the threshold. (3) Next, as shown in FIG. 5(3), data β of the estimated background light intensity at each position is calculated. Here, the estimated background light intensity may be calculated in any way. For example, the average background light intensity at each position can be calculated and used from the background light data A22, B22, C22, and D22. Specifically, if there is multiple light intensity data for a certain position, the average light intensity is used; if there is only one light intensity, the light intensity is used as is. Furthermore, if there is a position for which there is no data on the amount of background light, the average value of the amounts of light on both sides of the position may be used.(4) Finally, as shown in Fig. 5 (4), the difference data A3, B3, C3, D3 between the light intensity of each of the two-dimensional image data A1, B1, C1, D1 and the data β of the estimated value of the background light intensity calculated in (3) are calculated. The calculation results can then be used as the noise-reduced light distribution.

[0026] Of course, values ​​other than the average value can be used to calculate the estimated value. For example, when calculating the amount of background light contained in foreground light at a certain position, other two-dimensional image data having foreground light closer to the position of the foreground light may be more representative of background light due to the effects of multipath or the like. Therefore, in such cases, the estimated value may be calculated by weighting the amount of background light in other two-dimensional image data having foreground light closer to the position of the foreground light compared to the amount of background light in other two-dimensional image data having foreground light further away. Alternatively, the estimated value may be the amount of light calculated from the distance between the foreground light and the foreground light in other two-dimensional image data and the tendency of the background light. This calculation may be performed using a conventionally known method, such as the least squares method.

[0027] Next, the light irradiation means 10 that irradiates dot-shaped or line-shaped light will be specifically described. As the light irradiation means 10 that irradiates dot-shaped light, for example, as shown in Figures 6(a) and 6(b), one that is mainly composed of an optical element 1, a plurality of irradiation units 2, and a control unit 5 can be used.

[0028] As shown in Figures 6(a) and 6(b), the optical element 1 is composed of a periodic arrangement of lenses 11 that transmit light of wavelength λ. Here, the lens 11 has a focal point at a predetermined distance f (f>0) from the lens 11. Note that, in this specification, the focal length refers to the distance between the focal point and the lens surface closest to the focal point, as shown in Figure 6. Here, the x-, y-, and z-directions are perpendicular to each other, and the optical axis direction of the optical element 1 is the z-direction. Figure 6(a) is a view of the optical system device viewed in the y-direction, and Figure 6(b) is a view of the optical system device viewed in the x-direction.

[0029] The shape of the lens 11 can be freely designed to match the spreading pattern of the dots to be projected (hereinafter referred to as the dot pattern). For example, if you want to make the dot pattern circular, you can make the lens 11 a spherical lens. Also, if you want to make the dot pattern non-circular, you can make the lens 11 a suitably designed aspherical lens. In the case of an aspherical lens, the focal length differs depending on the direction. Figure 6(c) shows a cross-sectional shape perpendicular to the y direction where the focal length is f １ , the focal length due to the cross-sectional shape perpendicular to the x direction is f ２ (f １ ≠f ２ ), the pitch in the x direction is P １ , the size of the pitch in the y direction is P ２ The optical element is an example of an aspherical lens with a focal length f １ ya f ２ These can also be used in wide-angle lenses with a refractive index of 20 μm or less, 15 μm or less, and 10 μm or less, and in narrow-angle lenses with a refractive index of 60 μm or more, 65 μm or more, and 70 μm or more.

[0030] Furthermore, examples of the periodic arrangement of lenses include a square array of square or rectangular lenses 11 in a plan view, and a hexagonal array of hexagonal lenses 11 in a plan view. The lenses 11 may be of any material that functions as a lens, and in addition to general lenses such as convex lenses and concave lenses, Fresnel lenses, DOE lenses, metalenses, and the like may also be used. In the case of a convex lens, it is preferable that the convex lens portion faces the irradiation unit 8. The lenses may be made of any material, such as resin or glass.

[0031] The irradiation unit 2 has a light source 7 that irradiates a plurality of lenses 11 with light of wavelength λ. The irradiation unit 2 may be a single light source as shown in FIG. 7(c) or a plurality of light sources as shown in FIG. 7(b). When one irradiation unit 2 includes a plurality of light sources 7, the light sources 7 are formed so that when the positions of the light sources 7 relative to the lens 11 are overlapped and aggregated on one lens, the aggregated apparent positions of the light sources 7 coincide with each other. For example, the light sources included in the same irradiation unit are periodically arranged, and the pitch Px of the light sources in the x direction is equal to the pitch P of the lenses. １ and the pitch Py in the y direction is the lens pitch P ２ In other words, the light sources 7 included in the same irradiation unit 2 have a pitch in the x direction of Px, a pitch in the y direction of Py, and j and k are natural numbers of 1 or more, where Px=jP １ or jPx = P １ and Py = kP ２ or kPy = P ２ The elements may be arranged regularly so as to satisfy the following equation.

[0032] In addition, when the light sources 7 of the irradiation unit 2 are arranged in a square, the pitch P １ and Pitch P ２ P １ =P ２ In addition, when the light sources 7 of the irradiation unit 2 are arranged in a hexagonal array, the pitch P of the lenses 11 can be １ and Pitch P ２ 2P １ =√3P ２ or √3P １ =2P ２ It can be said that:

[0033] The light source 7 may be any type as long as it can irradiate multiple lenses 11 with light of wavelength λ. It is preferable that the light source 7 is formed on the same plane. The irradiation unit 2 and the optical element 1 may be arranged so that the optical axis direction of the light source of the irradiation unit 2 coincides with the optical axis direction of the lens 11 of the optical element 1. A specific example of the irradiation unit 2 is a VCSEL (Vertical Cavity Surface Emitting Laser), which is expected to achieve high output with low power consumption. VCSELs include single-emitter VCSELs, which have one light source 7 capable of irradiating light in a direction perpendicular to the light-emitting surface, and multi-emitter VCSELs, which have multiple light sources 7.

[0034] Furthermore, all of the irradiation units 2 may be formed on the same semiconductor chip, which eliminates the need to align the irradiation units or light sources in the x, y, and z directions when assembling the optical system device.

[0035] [Positional Relationship Between Irradiation Unit and Optical Element] As shown in FIG. 6, the distance L between the irradiation unit 2 and the first focal plane 111 of the lens 11 is １ , the distance L to the second focal plane 112 ２ can convert incident light into a dot pattern with high contrast when the following formulas α and β are satisfied: where m and n are natural numbers equal to or greater than 1, １ is the pitch of the lens 11 in the x direction, P ２ is the pitch in the y direction, λ is the wavelength of the light incident from the irradiation unit 2, and f １ is the focal length of the lens 11 due to the cross-sectional shape perpendicular to the y direction, and f ２ is the focal length of the lens 11 according to the cross-sectional shape perpendicular to the x-direction, and a, b, c, and d are coefficients indicating the allowable error.

[0036] The first focal plane 111 is a plane that is perpendicular to the optical axis (z direction) of the lens 11 and is located at the focal position of the cross-sectional shape of the lens 11 that is perpendicular to the y direction. The second focal plane 112 is a plane that is perpendicular to the optical axis (z direction) of the lens 11 and is located at the focal position of the cross-sectional shape of the lens 11 that is perpendicular to the x direction. The distance L １ , L２ means the distance (optical path length) that light travels in a vacuum in the same time as it travels in a medium, and is expressed as the product NL, where N is the refractive index of the medium and L is the actual distance. In addition, when the focal points are on both sides of the lens 11, it is preferable to use the first focal plane 111 and the second focal plane 112 located on the irradiation unit 2 side of the lens 11 as the reference.

[0037] Furthermore, the smaller the coefficient a in formula α, the more preferable it is, such as a = 1, a = 0.5, a = 0.3, and a = 0.1. The smaller the coefficient b, the more preferable it is, such as b = 1, b = 0.5, b = 0.3, and b = 0.1. The smaller the coefficient c in formula β, the more preferable it is, such as c = 1, c = 0.5, c = 0.3, and c = 0.1. The smaller the coefficient d, the more preferable it is, such as d = 1, d = 0.5, d = 0.3, and d = 0.1. When the coefficients of formula α and formula β are a = b = c = d = 1, formula α and formula β become formula 1 and formula 2 below, respectively.

[0038] In particular, when the coefficients of the formulas α and β are a=b=c=d=0, that is, when the distance L １ and L ２ However, when the following formulas 3 and 4 are satisfied, the light can be most reinforced.

[0039] Also, pitch P １ , P ２ If the pitch P is too small compared to the wavelength λ of the light from the light source 7, diffraction is unlikely to occur. Therefore, as long as the light distribution angle of the light source 7 includes a sufficient number of aspherical lenses 11 to cause diffraction, １ , P ２ is preferably sufficiently larger than the wavelength λ of the light from the light source 7, for example, 5 times or more, and preferably 10 times or more.

[0040] Furthermore, each irradiation unit 2 can be configured to include different types of irradiation units in which, when the positions of the light sources 7 relative to the lens 11 are superimposed on one lens for each irradiation unit and aggregated, the aggregated apparent positions of the light sources 7 are different from each other (hereinafter, irradiation units having such a relationship will be referred to as different types of irradiation units). In this way, by using different types of irradiation units 2, the positions of the dots formed when the light irradiated from each irradiation unit 2 passes through the optical element 1 will not all be completely aligned, so the number and positions of the dots can be adjusted by controlling the lighting of each irradiation unit. In this way, the light irradiation means 10 can switch and irradiate light to different positions.

[0041] This will be specifically explained using the four types of irradiation units 2A to 2D shown in FIG. 7( a). The optical element 1 is assumed to have square lenses 11 with sides of length P in a plan view arranged in a square array. For simplicity's sake, the light sources 7 included in each of the irradiation units 2A to 2D are assumed to be periodically arranged, as shown in FIG. 7( b), to have the same pitch as the pitch P of the lenses 11 of the optical element 1. The irradiation units 2A and 2B are assumed to be arranged such that the periodic positions of the light sources differ by a half pitch only in the x-axis direction, the irradiation units 2A and 2C are assumed to be arranged such that the periodic positions of the light sources differ by a half pitch only in the y-axis direction, and the irradiation units 2A and 2D are assumed to be arranged such that the periodic positions of the light sources differ by a half pitch in each of the x-axis and y-axis directions. When the positions of the light sources 7A of the irradiation unit 2A relative to the lenses 11 are arranged as shown in FIG. 8( A1 ), the apparent positions of the light sources 7A aggregated on a single lens 11 are as shown in FIG. 8( A2 ). Similarly, when the positions of the light sources 7B to 7D of the irradiation units 2B to 2D relative to the lens 11 are arranged as shown in Figures 8(B1) to 8(D1), the apparent positions of the light sources 7B to 7D when superimposed and aggregated on one lens 11 are as shown in Figures 8(B2) to 8(D2), respectively.

[0042] When the light sources 7A-7D of the irradiation units 2A-2D configured in this manner are turned on, the positions of the dots formed by light passing through the optical element 1 are all different. Therefore, for example, when only the irradiation unit 2A is used, the positions of the dots are as shown in FIG. 9(a). Furthermore, the positions of the dots formed by the irradiation units 2B, 2C, and 2D by light passing through the optical element 1 are as shown in FIGS. 9(b)-2(d), respectively, relative to the dots formed by the irradiation unit 2A by light passing through the optical element 1. Therefore, when the irradiation units 2A-2D are switched between, the positions of the dots formed by light passing through the optical element 1 are four, as shown in FIG. 2(e). Therefore, the positions of the formed dots can be adjusted by controlling the lighting of each irradiation unit. In other words, the light irradiation means 10 can switch between irradiating light to different positions. This allows the influence of background light due to multipath or other factors to be detected, thereby reducing noise and improving the signal-to-noise ratio.

[0043] The control unit 5 controls the lighting of each of the irradiation units 2. The control unit 5 may control the irradiation units 2 in any manner, but may, for example, control the different types of irradiation units 2 so that they are turned on in sequence. This allows light to be switched to be irradiated at different positions, and as described above, it is possible to reduce noise and increase the signal-to-noise ratio.

[0044] The control unit 5 may be any device that can control the lighting of the light source for each irradiation unit based on information from the imaging means 20, and for example, an existing computer, CPU, etc. may be used.

[0045] 10, the light irradiation means 10 for irradiating the line-shaped light may be mainly composed of an optical element 1, a plurality of irradiation units 2, and a control unit 5. The optical element 1 has lenses 11 that transmit light of wavelength λ and are arranged at a pitch P in the x direction. ｘ , pitch P in the y direction perpendicular to the x direction ｙ The lens 11 has a cross-sectional shape perpendicular to the y direction, and the focal length to the first focus is f １ , the focal length to the second focus according to the cross-sectional shape perpendicular to the x direction is f ２The lens 11 is disposed so that the focal point is located on the side of the lens 11 facing the irradiation unit 2. The optical element 1 can improve the contrast as the focal length f increases, for example, 10 μm or more, 20 μm or more, 40 μm or more, or 60 μm or more.

[0046] The shape of the lens 11 can be freely designed to satisfy the conditions described below. For example, the shape of the lens 11 can be set to f １ = f ２ A spherical lens with f １ ≠f ２ The lens 11 can be an aspherical lens in which the lens shape is such that the lens 11 is an aspherical lens having a shape similar to that of the lens 11. Specific lens shapes include, for example, convex lenses and concave lenses. The periodic arrangement of the lenses 11 can be a quadrangular arrangement of square or rectangular lenses in a plan view, or a hexagonal arrangement of hexagonal lenses in a plan view. The lens 11 can be any material that functions as a lens, and for example, a Fresnel lens, a DOE lens, a metalens, or the like can be used. In the case of a convex lens, it is preferable that the convex lens portion faces the irradiation unit 8. The lens can be made of any material, such as resin or glass.

[0047] The irradiation unit 2 has a plurality of light sources 7 that irradiate a plurality of lenses 11 with light of wavelength λ, the light sources 7 being spaced apart at a pitch Q in the x direction. ｘ , pitch Q in the y direction ｙ The light sources 7 may be arranged in any pattern as long as they are periodically arranged, and for example, as shown in Figures 11(a) and 11(b), a square pattern or a hexagonal pattern may be used. In addition, as shown in Figure 11(c), for example, the irradiation unit 2 has light sources 7 that irradiate a plurality of lenses 11 with light of wavelength λ, arranged at a pitch Q in the x direction. ｘThe light source 7 may be arranged in a line. Alternatively, multiple light sources may be formed by passing light from a single light source or multiple light sources through an aperture having multiple holes. When the irradiation unit 2 is configured with multiple light sources, it is preferable that the light sources 7 are formed on the same plane. A specific example of the irradiation unit 2 is a VCSEL (Vertical Cavity Surface Emitting Laser), which is expected to achieve high output with low power. A VCSEL has multiple light sources that can irradiate light in a direction perpendicular to the light-emitting surface. The light source 7 used in the irradiation unit 2 may be any light source that irradiates multiple lenses 11 with light of wavelength λ.

[0048] The irradiation unit 2 and the optical element 1 are arranged so that the optical axis direction of the light source 7 of the irradiation unit 2 and the optical axis direction of the lens 11 of the optical element 1 are aligned.

[0049] [Positional Relationship Between Irradiation Unit and Optical Element] Next, as the irradiation unit 2, the light source 7 is arranged at a pitch Q in the x direction. ｘ , pitch Q in the y direction ｙ The positional relationship between the irradiation unit 2 and the optical element 1 will be described below in the case where j, k, m, and n are natural numbers of 1 or more, and the focal length to the first focal point of the cross-sectional shape of the lens 11 perpendicular to the y direction is f. １ , the focal length to the second focus according to the cross-sectional shape perpendicular to the x direction is f ２ In addition, a plane perpendicular to the z direction including the first focal point is defined as a first focal plane, and a plane perpendicular to the z direction including the second focal point is defined as a second focal plane. In this case, the distance L between the irradiation unit 2 and the first focal plane 111 of the lens 11 is １ is expressed by the following formula 5 and the pitch of the light sources 7 of the irradiation unit 2 is Q ｘ =jp ｘ or jQ ｘ =P ｘ The distance L between the irradiation unit 2 and the second focal plane 112 of the lens 11 is ２ is expressed by the following formula 6 does not satisfy the above condition, or the pitch of the light source 7 of the irradiation unit 2 is ｙ = kP ｙ and kQ ｙ =P ｙBy arranging the light beams in this way, a line of light extending in the Y direction is emitted.

[0050] Here, the distance L １ It is most preferable that the following formula 7 is satisfied.

[0051] In addition, the distance L ２ does not satisfy the above formula 6, and further, Q ｙ = kP ｙ and kQ ｙ =P ｙ It is preferable to arrange them so that the above condition is not satisfied.

[0052] The light sources 7 of the irradiation unit 2 are arranged at a pitch Q in the y direction. ｙ The positional relationship between the irradiation unit 2 and the optical element 1 will be described below in the case where k, m, and n are natural numbers of 1 or more, and the focal length of the lens 11 according to the cross-sectional shape perpendicular to the y direction is f １ , the focal length of the cross-sectional shape perpendicular to the x direction is f ２ In this case, the distance L between the irradiation unit 2 and the first focal plane 111 of the lens 11 is １ is expressed by the following formula 5 The distance L between the irradiation unit 2 and the second focal plane 112 of the lens 11 is ２ is expressed by the following formula 6 does not satisfy the above condition, or the pitch of the light source 7 of the irradiation unit 2 is ｙ = kP ｙ or kQ ｙ =P ｙ By arranging the light beams in this way, a line of light extending in the Y direction is emitted.

[0053] Here, the distance L １ It is most preferable that the following formula 3 is satisfied.

[0054] In addition, the distance L ２ does not satisfy the above formula 2, and further, Q ｙ = kP ｙ and kQ ｙ =P ｙ It is preferable to arrange them so that the above condition is not satisfied.

[0055] By irradiating the irradiation portions of the optical element arranged in this way with light sources that are turned on in sequence, for example, it is possible to switch the light to irradiate different positions. This makes it possible to detect the influence of background light due to multipath, etc., thereby reducing noise and increasing the signal-to-noise ratio.

[0056] The control unit 5 controls the lighting of each of the irradiation units 2. The control unit 5 may control the irradiation units 2 in any way, but for example, it may control different types of irradiation units 2 to light up in sequence. This makes it possible to switch and irradiate light to different positions, and as described above, it is possible to reduce noise and increase the signal-to-noise ratio.

[0057] The control unit 5 may be any device that can control the lighting of the light source for each irradiation unit based on information from the imaging means 20, and for example, an existing computer, CPU, etc. may be used.

[0058] As another light irradiation means 10 for irradiating line-shaped light, for example, as shown in FIG. 12, one mainly composed of a plurality of irradiation units 2, a cylindrical lens 3, a diffuser 4, and a control unit 5 can be used.

[0059] As shown in Figures 12 and 13, the cylindrical lens 3 is used to convert the light from the irradiation unit 2 into light at a predetermined elevation angle relative to the y direction (the angle relative to the y axis in the zy plane). The cylindrical lens 3 also converts the light into light with a different elevation angle for each irradiation unit 2. This allows the irradiation units 2 to be turned on in the appropriate order, thereby irradiating light of the required intensity at the required angle without using any moving parts. The irradiation units 2 and the cylindrical lens 3 are arranged so that the optical axis direction of the irradiation unit 2 and the optical axis direction of the cylindrical lens 3 are aligned. It is preferable that the cylindrical lens 3 converts the light from each irradiation unit 2 into parallel light.

[0060] Furthermore, it is preferable that the cylindrical lens 3 converts the light from each irradiation unit 2 into different light at equal elevation angles. In this case, it is preferable that the angle be such that the light from each irradiation unit 2 that has passed through the cylindrical lens 3 is filled in just the right amount.

[0061] The cylindrical lens 3 may be designed by a conventionally known method. The cylindrical lens 3 may be made of any material, such as resin or glass.

[0062] The diffuser 4 is used to spread the light transmitted through the cylindrical lens 3 in the x direction. Well-known technologies can be used as long as they can spread the light transmitted through the cylindrical lens 3 in the x direction. For example, methods using a diffractive optical element (DOE) or a microlens array are known for the diffuser 4. Furthermore, an optical element with high optical efficiency and reduced uneven light distribution, such as the optical element described in WO 2023 / 032094 A1, may be used. Here, the diffuser 4 may spread the transmitted light in the x direction so that the light intensity is uniform, or it may change the light intensity in a specific direction along a line. For example, in an optical system device in which light is reflected by an object 9 and returned to a camera, the intensity of the light returning to the camera weakens as the exit angle of the irradiated light increases. Therefore, taking into account the intensity of the light returning to the camera, the light intensity may be increased as the exit angle increases. The diffuser 4 may be made of any material, such as resin or glass.

[0063] The irradiation unit 2 is for irradiating the cylindrical lens 3 with light. If the optical axis direction of the irradiation unit 2 is the z direction, the irradiation unit 2 irradiates linear light in the x direction perpendicular to the z direction. As shown in Fig. 13, a plurality of irradiation units 2 are arranged at intervals in the y direction perpendicular to the x and z directions. Each irradiation unit 2 can irradiate light independently.

[0064] The irradiation unit 2 may be any type capable of irradiating light onto the cylindrical lens 3. For example, a unit consisting of multiple light sources arranged in the x direction may be used. In this case, the light sources of one irradiation unit 2 may be arranged in a single row or multiple rows. Another irradiation unit may be one that irradiates light from the light sources through linear slits in the x direction. The light intensity of each irradiation unit 2 may be the same or different. For example, in an optical system device in which light is reflected by an object 9 and returned to a camera, the intensity of the light returning to the camera decreases as the exit angle of the irradiated light increases. Therefore, taking into account the intensity of light returning to the camera, the light intensity may be increased for light with a larger exit angle. A specific example of the irradiation unit 2 is a VCSEL (Vertical Cavity Surface Emitting Laser), which can irradiate light perpendicular to the light-emitting surface and is expected to achieve high output with low power consumption.

[0065] The interval between each of the irradiation units 2 may be determined in any manner depending on the application, but a smaller interval is preferable in that it allows for a reduction in the size of the cylindrical lens 3 and the diffuser 4. Specifically, the interval between each of the irradiation units 2 may be set at a pitch of 100 to 200 μm.

[0066] Furthermore, it is preferable that the irradiation units 2 are formed on the same plane. More preferably, all of the irradiation units 2 are formed on the same semiconductor chip. For example, a multi-emitter VCSEL having multiple light sources can be used, in which each light source on a line in the x direction can be controlled independently. This makes it possible to eliminate the need to align the irradiation units in the x, y, and z directions when assembling the optical system device.

[0067] In this way, the illumination unit 2 can illuminate different positions by, for example, switching the light sources that are turned on in order, which makes it possible to detect the influence of background light due to multipath or the like, thereby reducing noise and increasing the signal-to-noise ratio.

[0068] The control unit 5 is for controlling the lighting of each of the irradiation units 2. The control unit 5 may control the irradiation units 2 in any way, but for example, it may be possible to light each of the irradiation units 2 in sequence. By controlling in this way, it is possible to switch and irradiate light to different positions by changing the order of the irradiation units that are turned on, and as described above, it is possible to reduce noise and increase the S / N ratio.

[0069] The control unit 5 may be any device that can control the lighting of each irradiation unit 2, and may be, for example, an existing CPU or computer. The control unit 5 may also be formed on the same semiconductor chip as each irradiation unit 2. This can further reduce energy consumption and assembly costs.

[0070] REFERENCE SIGNS LIST 1 Optical element 2 Irradiation unit 3 Cylindrical lens 4 Diffuser 5 Control unit 7, 7A to 7D Light source 8A to 8D Dot-shaped light 9 Object 11 Lens 10 Light irradiation means 20 Imaging means 30 Computing means 111 First focal plane 112 Second focal plane

Claims

1. An optical system device comprising: a light irradiation means capable of switching light irradiation to different positions; an imaging means for detecting information about the received light; and a calculation means for switching the position of the light irradiated by the light irradiation means and reducing noise from the information based on the light information detected by the imaging means.

2. The light irradiation means comprises an optical element in which lenses that transmit light of wavelength λ are periodically arranged, a plurality of irradiation units having light sources that irradiate a plurality of the lenses with light of wavelength λ, and a control unit that controls the lighting of each of the irradiation units, where m and n are natural numbers of 1 or more, and the focal length of the cross-sectional shape of the lens perpendicular to the y direction is f １ , the focal length of the cross-sectional shape perpendicular to the x direction is f ２ , the size of the pitch of the lens in the x direction is P １ , the size of the pitch in the y direction is P ２ Then, the distance L between the irradiation unit and the first focal plane of the lens is １ , distance L to the second focal plane ２ is expressed by the following formula 1 and formula 2 2. The optical system according to claim 1, wherein the following is satisfied:

3. The optical system device according to claim 2, characterized in that the illumination units include different types of illumination units in which the positions of the light sources relative to the lenses are superimposed on one lens for each illumination unit, and the positions of the aggregated apparent light sources are different from each other.

4. The light sources included in the same irradiation unit are a plurality of light sources that are periodically arranged, and the pitch of the light sources in the x direction is the same as the lens pitch P １ and the pitch in the y direction is the lens pitch P ２ 4. The optical system according to claim 2, wherein the optical axis is a natural number multiple or an inverse multiple of a natural number.

5. Distance L １ and L ２ is expressed by the following formula 3 and formula 4.

4. The optical system according to claim 2, wherein the following is satisfied:

6. The light irradiation means has lenses that transmit light of wavelength λ arranged at a pitch P in the x direction. ｘ , pitch P in the y direction perpendicular to the x direction ｙ and a light source that irradiates a plurality of the lenses with light of wavelength λ is arranged at a pitch Q in the x direction. ｘ , pitch Q in the y direction ｙ and a control unit that controls lighting of each of the irradiation units, wherein j, k, m, and n are natural numbers of 1 or more, and a focal length to a first focus according to a cross-sectional shape of the lens perpendicular to the y direction is f. １ , the focal length to the second focus according to the cross-sectional shape perpendicular to the x direction is f ２ , a plane perpendicular to the z direction including the first focal point is defined as a first focal plane, and a plane perpendicular to the z direction including the second focal point is defined as a second focal plane, the distance L between the irradiation unit and the first focal plane of the lens is defined as １ is expressed by the following formula 1 and the pitch of the light sources of the irradiation unit is Q ｘ =jp ｘ or jQ ｘ =P ｘ and the distance L between the irradiation unit and the second focal plane of the lens is ２ is expressed by the following formula 2 does not satisfy, or the pitch of the light source of the irradiation unit is Q ｙ = kP ｙ and kQ ｙ =P ｙ 2. The optical system according to claim 1, wherein the following condition is not satisfied:

7. The light irradiation means has lenses that transmit light of wavelength λ arranged at a pitch P in the x direction. ｘ , pitch P in the y direction perpendicular to the x direction ｙ and a light source that irradiates a plurality of the lenses with light of wavelength λ is arranged at a pitch Q in the y direction. ｙ and a control unit that controls the lighting of each of the irradiation units, wherein k, m, and n are natural numbers of 1 or more, and the focal length to a first focus of the cross-sectional shape of the lens perpendicular to the y direction is f. １ , the focal length to the second focus according to the cross-sectional shape perpendicular to the x direction is f ２ , a plane perpendicular to the z direction including the first focal point is defined as a first focal plane, and a plane perpendicular to the z direction including the second focal point is defined as a second focal plane, the distance L between the irradiation unit and the first focal plane of the lens is defined as １ is expressed by the following formula 1 and the distance L between the irradiation unit and the second focal plane of the lens is ２ is expressed by the following formula 2 does not satisfy, or the pitch of the light source of the irradiation unit is Q ｙ = kP ｙ and kQ ｙ =P ｙ 2. The optical system according to claim 1, wherein the following condition is not satisfied:

8. The optical system device according to claim 1, characterized in that the light irradiation means comprises a plurality of irradiation units, each of which emits a line-shaped light in the x direction and is arranged in the y direction perpendicular to the x direction; a cylindrical lens that converts the light from the irradiation units into light having a different elevation angle with respect to the y direction for each irradiation unit; a diffuser that spreads the light that has passed through the cylindrical lens in the x direction; and a control unit that controls the lighting of each of the irradiation units.

9. The optical system according to claim 8, wherein said cylindrical lens converts the light from each of said irradiating units into parallel light.

10. An optical system according to claim 8, wherein said cylindrical lens converts the light from each of said irradiating sections into different light beams with equal elevation angles.

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