JP2020009749A - Light source, projection device, measuring device, robot, electronic device, moving object, and modeling device - Google Patents

Abstract

To reduce speckle noise without increasing the size nor cost of a projection part.SOLUTION: A light source according to one embodiment of the present invention has a plurality of light emitting elements in a plane. A plurality of light emitting elements are arranged at such element intervals that irradiation lights of the plurality of light emitting elements overlap in an assumed projection region, and also at such element intervals that speckle patterns of the respective irradiation lights obtained in the assumed projection region differ with the irradiation lights.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a light source, a projection device, a measurement device, a robot, an electronic device, a moving object, and a modeling device.

  Laser light sources have advantages not found in LEDs (Light Emitting Diodes), such as higher output by resonator amplification and focus-free, and are used in various devices such as projectors and distance measurement. However, excessive coherence (coherence), which is a characteristic property of laser light, causes flickering of speckle noise called speckle noise on a retina of an eye, which is an observation surface for observing an irradiation target, or an image sensor of a camera. Speckle noise adversely affects image quality and measurement accuracy and is a disadvantage in using a laser. Therefore, it is necessary to reduce speckle noise when using a laser.

  For the purpose of reducing speckle noise, there is disclosed a surface emitting semiconductor laser array having a plurality of light emitting units and a laser light source having a control unit for controlling the plurality of light emitting units to switch a light emitting pattern (Patent) Reference 1).

  However, conventionally, in the case of reducing speckle noise, a method of changing the speckle pattern by devising a light source or a light receiving side and averaging (superimposing) them to reduce the noise has been used. To achieve this, there is a problem that the size of the light projecting section is increased and the cost is increased due to the complicated system.

  The present invention has been made in view of the above, and is a light source, a projection device, a measurement device, a robot, and an electronic device capable of reducing speckle noise without increasing the size of a light projection unit and increasing costs. , A moving body, and a modeling apparatus.

  In order to solve the above-described problem and achieve the object, a light source according to an embodiment of the present invention has a plurality of light-emitting elements in a plane, and the element arrangement of the plurality of light-emitting elements is based on an assumed projection area. , Wherein a plurality of light-emitting elements satisfy the element intervals at which the irradiation light overlaps, and a speckle pattern of each irradiation light obtained in the assumed projection area satisfies a different element distance for each irradiation light.

  ADVANTAGE OF THE INVENTION According to this invention, there exists an effect that it becomes possible to reduce speckle noise, without enlarging a light projection part and cost increase.

FIG. 1 is a conceptual diagram showing the principle of generation of speckle noise of a laser. FIG. 2 is a diagram illustrating the relationship between the interval between light sources and the angle of incidence on an observation point. FIG. 3 is a diagram showing experimental results when a 40 cH-VCSEL light source (λ = 780 nm) having a pitch between light emitting elements of 50 μm or less is used. FIG. 4 is a diagram illustrating an example of an experimental result when θ is changed. FIG. 5 is a diagram illustrating an example of a layout configuration of the VCSEL array according to the first embodiment. FIG. 6 is a diagram illustrating an example of a speckle photographed image in the case where 1 cH (one light emitting element) is turned on using the VCSEL array shown in FIG. 5 and in the case where all 100 cH are turned on. FIG. 7 is a diagram illustrating an experimental result of a speckle noise reduction effect when the VCSEL array according to the first embodiment is used. FIG. 8 is a diagram illustrating an example of a layout configuration of the VCSEL array according to the second embodiment. FIG. 9 is a diagram illustrating an example in which the arrangement order of the light emitting elements having different wavelengths in the set is random. FIG. 10 is a diagram showing a modification of the configuration of the VCSEL array. FIG. 11 is a diagram illustrating an example of a configuration of a projection device according to the second embodiment. FIG. 12 is a diagram illustrating an example of the configuration of the light deflecting element. FIG. 13 is a diagram illustrating an example of a measurement device according to the third embodiment. FIG. 14 is a diagram illustrating an example of a block configuration of the measurement device. FIG. 15 is a diagram illustrating an example of a configuration of a robot according to the fourth embodiment. FIG. 16 is a diagram illustrating an example of a configuration of an electronic device such as a smartphone according to the fourth embodiment. FIG. 17 is a diagram illustrating an example of a configuration of a vehicle according to the fifth embodiment. FIG. 18 is a diagram illustrating an example of a configuration of another moving object according to the fifth embodiment. FIG. 19 is a diagram illustrating an example of a configuration of a 3D printer according to the sixth embodiment.

  Hereinafter, embodiments of a light source, a projection device, a measurement device, a robot, an electronic device, a moving object, and a modeling device will be described with reference to the accompanying drawings. The present invention is not limited by the following embodiments.

(First Embodiment)
First, speckles appearing on the observation surface according to the first embodiment and the principle of eliminating the speckles will be described.

  FIG. 1 is a conceptual diagram showing the principle of generation of laser speckle (speckle noise). FIG. 1A shows a system including a laser light source 1000, a screen 1001, and a camera 1002. FIG. 1B shows an observation image (speckle image) 1003 observed by the camera 1002 when a solid image is projected from the laser light source 1000 onto the screen 1001. This observation image 1003 includes speckles developed on the image sensor of the camera 1002.

  When a solid image is projected from the laser light source 1000 onto the screen 1001, a part of the light P1 constituting the solid image is multiple-scattered inside the surface of the screen 1001. The multiply scattered light comes out of the surface of the screen 1001 to the outside. The scattered light P2 coming out of the screen 1001 is added with a random phase component due to the irregularity (unevenness) of the surface of the screen 1001. I have. The scattered light P2 is converged on the observation surface (imaging element) of the camera 1002 via an optical system such as a lens, and the scattered light P2 interferes with each other on the observation surface and overlaps because the laser light is coherent light. As a result, bright spots and dark spots appear randomly on the observation surface, and speckled speckle patterns are observed. The light and dark flickers are noise sources that have an adverse effect on image quality and various measurements. This phenomenon is a complicated one involving all elements of the light projecting system, the subject, and the light receiving system. The speckle pattern observed by the lens of the camera 1002 and the pixel size of the image sensor greatly changes.

  FIG. 1B shows an observation image 1003 when observed with the camera 1002. Even when the solid image projected on the screen 1001 is observed with human eyes, such as a laser display, instead of the camera 1002. A similar speckle pattern appears on the retina.

Next, the fact that speckle noise can be reduced will be qualitatively described. First, the speckle noise index will be described. The following equation (1) is an equation representing speckle contrast (Cs) used as an index of speckle noise.
Cs = σ / S (1)

  In Equation (1), S is the average luminance value of the captured image when the solid image is projected, and σ is the standard deviation. As shown in equation (1), Cs is represented by the reciprocal of the signal-to-noise ratio (SNR) indicating general signal strength. The lower the contrast value indicated by Cs in the equation (1), the lower the speckle noise and the smaller the flicker.

  The speckle pattern observed on the observation surface is a complicated pattern involving all elements of the light projecting system, the subject, and the light receiving system. In general, if there are a plurality of laser light sources 1000, the speckle pattern developed by each laser light source 1000 is not the same but random. Therefore, if a plurality of laser light sources 1000 are provided, different speckle patterns are generated for each laser light source 1000, and these speckle patterns are superimposed on the observation surface, the speckle noise of the observation surface is obtained by a plurality of random speckle patterns. Are averaged, and speckle noise is reduced.

Based on this concept, the equation (1) is further modified for the relationship between the averaging and reduction of speckle noise. For n speckle patterns (where n is a natural number) overlapping on the observation surface (an image of each speckle pattern is called a speckle image), the average luminance of the speckle image k is S _k , the standard deviation is σ _k , speckle contrast to Cs _k. In this case, when the irradiation source of the laser light source 1000 to the same power, the average luminance S _k of each speckle _image, the standard deviation sigma _k, since equal speckle contrast Cs _k, the following equation (2) to (4 ) Can be considered.
S ₁ = S ₂ = S ₃ =... = S _n = S (2)
σ ₁ = σ ₂ = σ ₃ = ... = σ _n = σ (3)
Cs ₁ = Cs ₂ = Cs ₃ =... = Cs _n = Cs (4)

Therefore, the luminance value S _SUM when the n speckle images are combined is given by the following equation (5) when the condition of the equation (2) is applied.
S _SUM = S ₁ + S ₂ + S ₃ +... + S _n = S × n (5)

For the standard deviation σ _SUM , the additive nature of the variance of the following equation (6) can be used.
^{_{σ SUM 2 = σ 1 2 +}} σ 2 2 + σ 3 2 + ··· + σ n 2 ··· (6)

When the condition of Expression (3) is applied to Expression (6), the following Expression (7) is obtained.
σ _SUM = √ (σ ² × n) = σ√n (7)

From the above, the speckle contrast (Cs _SUM ) of an observation image observed by superimposing n speckle images is given by the following equation (8).

Cs _SUM = σ√n / (S × n) = (√n / n) × (σ / S) = 1 / √n × Cs
... (8)
Equation (8) shows that averaging n speckle images improves (reduces) the speckle contrast to 1 / √n. Therefore, in the calculation, when the number of the laser light sources 1000 is n, the speckle contrast (Cs) can be expected to be improved by 1 / √n.

  Here, in order to obtain the above calculation result, it is necessary to superimpose a plurality of random speckle patterns, that is, it is premised that the speckle patterns appearing by each laser light source 1000 are different. This problem can be achieved, for example, by using multiple light source angle multiplexing. In the multiple light source angle multiplexing, a speckle image is multiplexed in such a manner that a different speckle pattern is generated for each light source by making an incident angle of light to an observation point different for each light source. Accordingly, in the following, the setting of a surface-emitting type semiconductor laser satisfying the above equation (8) will be discussed using the multiple light source angle multiplexing as an example.

  FIG. 2 is a diagram illustrating the relationship between the interval between light sources and the angle of incidence on an observation point. The system shown in FIG. 2 shows a system including a camera 1002, a screen 1001, and a VCSEL (Vertical Cavity Surface Emitting LASER) light source 1100.

  The VCSEL light source 1100 is an example of a “surface emitting semiconductor laser”. The VCSEL light source 1100 has a number of light emitting elements 1101 corresponding to the laser light source 1000 in the plane. Here, only two light emitting elements 1101 out of a large number of light emitting elements 1101 are shown for the description of the incident angle. Each light emitting element 1101 is an element such as a semiconductor laser diode that emits coherent light.

  The screen 1001 uses a white diffusion plate. In this system, by changing the distance (LWD) from the VCSEL light source 1100 to the screen 1001 and the distance (D) between the two light emitting elements 1101 of the VCSEL light source 1100, the light is incident on the screen 1001 from the two light emitting elements 1101 respectively. Changes the angle θ. For example, when the distance (D) between the light emitting elements 1101 is increased, θ increases, and when the distance (LWD) to the screen 1001 increases, θ decreases. That is, the value of θ can be changed by adjusting the interval between the light sources.

  FIG. 3 is a diagram showing an experimental result when a 40 cH-VCSEL light source having a pitch (D) between light emitting elements of 50 μm or less is used. The oscillation wavelength of each light emitting element is uniformly λ = 780 nm. In FIG. 3, the measurement results of speckle noise are plotted, with the horizontal axis representing the number of lighting light sources (n) and the vertical axis representing the rate of change of speckle contrast (Cs). The vertical axis indicates the rate of change when the speckle pattern when n = 1 is used as a reference for the speckle contrast (Cs).

  The dashed line graph in FIG. 3 is a curve (theoretical value curve) representing the theoretical value of 1 / √n indicated by the equation (8). From this measurement result, it can be seen that the speckle contrast (Cs) is reduced following the curve graph of the theoretical value and the speckle noise is reduced until the number of lighting light sources is 4 (that is, n = 4). . However, even if the number of lighting light sources is sequentially increased from four after n = 4, the speckle contrast (Cs) hardly changes and speckle noise does not decrease as expected.

  However, even if the number of lighting light sources is increased to 40, the speckle contrast (Cs) hardly changes as compared with the case where the number of lighting light sources is 4, and the actual reduction effect is only 1/3 or less of the theoretical value. .

  From this result, it can be seen that the effect of reducing speckle noise stops at a certain level only by simply increasing the number of lighting light sources, and it is not possible to expect a sufficient reduction in speckle noise even if the number of lighting light sources is increased. Therefore, it can be seen that the effect of reducing speckle noise is limited by simply using a VCSEL light source 1100 in which a plurality of light emitting elements are arranged.

  Therefore, the present inventor has studied a design in which the light emitting element that contributes to speckle reduction is efficiently integrated in the VCSEL light source 1100.

  In the experiment, θ is changed by gradually changing the element interval (D) of the VCSEL light source 1100 shown in FIG. Then, at each value of θ, one light emitting element and the light emitting elements at element intervals corresponding to θ are turned on, and the screen 1001 is photographed by the camera 1002. Then, the speckle contrast (Cs) of the overlapping speckle patterns is measured for each value of θ from the image captured by the camera 1002.

  FIG. 4 is a diagram illustrating an example of an experimental result when θ is changed. FIG. 4 shows the experimental results when the horizontal axis is θ and the vertical axis is the rate of change of speckle contrast (Cs).

  From the results shown in FIG. 4, the speckle contrast (Cs) decreases as θ increases, and when the speckle contrast (Cs) reaches approximately 0.04 to 0.05 °, the theoretical value 1 / √2 represented by the equation (8) is obtained. It turns out that it converges to. From this experimental result, it can be seen that there is θ converging to the theoretical value 1 / √2. Hereinafter, the setting that converges to the theoretical value indicated by the experimental result is collectively referred to as “setting having a speckle noise reduction effect”.

  As described above, the value of 0.04 to 0.05 ° itself is not an absolute value because it changes depending on various conditions such as the geometric conditions of the camera 1002 and the screen 1001 and the surface roughness of the measurement target. When the effect of reducing speckle noise is obtained by angle multiplexing of a plurality of light sources using the VCSEL light source 1100, a design layout (element to secure an appropriate distance between the light emitting elements 1101 in consideration of a distance to an object and the like. Placement) is required. That is, if the light emitting elements are integrated on the VCSEL light source surface at appropriate element intervals based on the experimental results, it is possible to reduce speckle noise without increasing the size of the light projecting unit and increasing the cost.

  Subsequently, an example of a layout configuration of a VCSEL light source in which a light emitting element is integrated is shown in “setting having speckle noise reduction effect” shown in the experimental results of FIG.

(Example 1)
FIG. 5 is a diagram illustrating an example of a layout configuration of the VCSEL array according to the first embodiment. The VCSEL array 11 shown in FIG. 5 has a layout configuration in which 100 surface-emitting light emitting elements a are arranged at equal pitches at the same element spacing in the VCSEL array surface.

  In FIG. 5, the number at the position of X of the light emitting element a (X, Y) represents a row number, and the number at the position of Y represents a column number. That is, the total number of the light emitting elements a is 5 rows × 20 columns = 100. Since the number of terminals is limited, each light emitting element a is not individually turned on, but is controlled to be turned on, for example, by two lines of 1, 2, 9,... However, the reason why n is set to two lines is to facilitate comparison with the theoretical value of the speckle reduction effect, and the present invention is not limited to this.

  The element interval (pitch) of each sending element a was set to 300 μm, which satisfies the following two conditions, in order to “set a speckle noise reduction effect”. Note that 300 μm is shown as an example and is not limited to this.

  Condition 1: an element interval at which irradiation light from a plurality of light emitting elements overlaps in an assumed projection area

  Condition 1 is that, for example, in consideration of an assumed screen distance (LWD) and a radiation angle (FFP) of the light emitting element, light of the light emitting elements at both ends of the VCSEL array 11 sufficiently overlaps in the irradiation area (projection area) of the screen. That is the condition. If the light from the light emitting elements at both ends is sufficiently overlapped, the light from the light emitting element between them should also be sufficiently overlapped. Note that this is an example in the case where all the arranged light sources are used, and a speckle reduction effect can be obtained as long as at least the interval between the irradiation lights of the adjacent light emitting elements among the plurality of light emitting elements overlaps.

  Condition 2: an element interval in which a speckle pattern of each irradiation light obtained in an assumed projection area is different for each irradiation light

  Condition 2 is a condition indicating that an angle (θ) formed by each laser beam required for light source multiplexing at an assumed screen distance (LWD) can secure a value that converges to a theoretical value. That the angle (θ) can secure a value that converges to the theoretical value means that the condition that the speckle pattern of each irradiation light is different for each irradiation light is satisfied even if the number of light emission is increased. .

  FIG. 6 is a diagram illustrating an example of a speckle photographed image when 1 cH (one light emitting element) is turned on using the VCSEL array 11 illustrated in FIG. 5 and when 100 cH is all turned on. FIG. 6A is a speckle photographed image when lighting at 1 cH is performed, and FIG. 6B is a speckle photographed image when lighting is performed at all 100 cH.

  Comparing these photographed images, the photographed image when 100 cH is turned on is dramatically less bright and dark flicker than the photographed image when 1 cH is turned on, and the speckle noise reduction effect by the light source multiplexing is effective. You can see that it is.

  FIG. 7 is a diagram illustrating an experimental result of a speckle noise reduction effect when the VCSEL array 11 according to the first embodiment is used. FIG. 7 is different from the experimental result of the 40cH-VCSEL light source shown in FIG. 3 in that the speckle contrast (Cs) continues to decrease and follows the dashed curve graph (theoretical value) even when the number of lighting light sources is increased. A speckle noise reduction effect close to the theoretical value can be obtained.

  In FIG. 7, there is a slight difference between the measured value of the plot and the theoretical value of the broken line. This difference is that the captured image includes all the fluctuation factors such as the pixel variation of the camera itself. It is considered as one factor. Further, as the number of lighting light sources is increased, there is a possibility that a similar speckle pattern may exist among them, which is also considered to be one factor. In order to accurately measure a slight difference, a device for measuring minute speckle noise is required because the observation system itself has a measurement limit.

  From the above results, if the element spacing of the light emitting elements is appropriately set so as to satisfy the above conditions 1 and 2, even if a large number of light emitting elements are provided in one VCSEL light source chip, the number of light emitting elements can be changed. As a result, the effectiveness of the speckle noise reduction effect of 1 / √n was obtained. Therefore, if the light emitting element is integrated in the surface of the VCSEL light source so as to satisfy the above conditions 1 and 2, it is possible to reduce speckle noise without increasing the size of the light projecting unit and increasing the cost. become.

  Note that the layout illustrated in FIG. 5 is an example, and the number of light-emitting elements, the shape of the opening, the arrangement of the light-emitting elements, and the like are not limited thereto. If the conditions 1 and 2 are satisfied, the number of light emitting elements, the shape of the opening, the arrangement of the light emitting elements, and the like may be appropriately changed.

(Example 2)
FIG. 8 is a diagram illustrating an example of a layout configuration of a VCSEL array including light emitting elements a having different oscillation wavelengths (hereinafter, abbreviated as wavelengths) according to the second embodiment. The light-emitting elements a of different wavelengths (in order of wavelength, wavelength λ1, wavelength λ2, wavelength λ3, wavelength λ4, wavelength λ5) are arranged one-dimensionally.

  The speckle pattern is formed when scattered light having a disordered phase generated when a laser is irradiated on a screen interferes with each other on an observation surface. The phase shift of the scattered light is mainly determined by the optical path length due to the undulations (irregularities) of the screen surface and the laser oscillation wavelength. In the multiple light source angle multiplexing of the first embodiment, the speckle pattern is changed by changing the optical path length according to the angle θ formed by the laser light of each light source and changing the phase of the scattered light. On the other hand, in the second embodiment, the phase of the scattered light is changed by modulating the oscillation wavelength of the laser itself, and noise is reduced by superimposing the changed speckle pattern (wavelength multiplexing). Therefore, when wavelength multiplexing is used to obtain different speckle patterns, it is not always necessary to satisfy Condition 2 for a single wavelength, and there is an advantage that layout restrictions are eased.

  In FIG. 8, light-emitting elements a (light-emitting element groups) of five different wavelengths (wavelength λ1, wavelength λ2, wavelength λ3, wavelength λ4, wavelength λ5) are set as a minimum unit, and a total of 10 sets (5 types) (Wavelength × 10 sets = 50) (light emitting elements a) are arranged one-dimensionally at a pitch of 30 μm.

  The arrangement order of the light emitting elements a in each set is a predetermined wavelength order. That is, the light emitting elements a of each wavelength are periodically arranged, and the pitch of the light emitting elements a of the same wavelength between each set is 150 μm (30 μm × 5 = 150 μm). Note that this setting is based on the premise that a system that requires an inter-element pitch of 150 μm or more to obtain a speckle reduction effect by light source multiplexing.

  By setting the inter-element pitch in such a layout, each light-emitting element a of the same wavelength included in all sets satisfies the inter-element pitch required for multiple light source angle multiplexing, so that adjacent light emitting elements a in each set are adjacent to each other. Since the light emitting elements a have different oscillation wavelengths, they have different speckle patterns. Therefore, even in the layout of the second embodiment, the effect of reducing speckle noise according to the number of light emitting elements can be expected.

  When 50 light emitting elements a are linearly and one-dimensionally arranged as in the present embodiment, each light emitting element a is 7.35 mm (calculation formula: 150 μm × (50-1)) in the case of light source multiplexing of a single wavelength. = 7.35 mm) becomes 1.47 mm (calculation formula: 30 μm x (50-1) = 1.47 mm), so even if the chip size is reduced to 1/5, the same 1 / A speckle contrast reduction effect of # 50 is obtained.

  Note that the layout illustrated in FIG. 8 is an example, and the number of light-emitting elements included in the light-emitting element group, the order of wavelength, the shape of the opening, the arrangement of the light-emitting element group, and the like are not limited thereto. If the wavelength multiplexing condition is satisfied in addition to the conditions 1 and 2, the number of light emitting elements included in the light emitting element group, the order of wavelengths, the shape of the opening, the arrangement of the light emitting element group, and the like may be appropriately modified.

  FIG. 9 shows the arrangement order of the light emitting elements of different wavelengths (wavelength λ1, wavelength λ2, wavelength λ3, wavelength λ4, wavelength λ5) in the set, and the light emitting elements of the wavelengths adjacent to λ1, λ4, λ2, λ5, λ3. This is an example in which is randomized so as not to be adjacent to each other. With this arrangement, the wavelength difference between adjacent light emitting elements is larger than in FIG. 8 arranged in order of wavelength, so that even if the finish of the wavelength of each light emitting element varies, the wavelength difference between adjacent light emitting elements is ensured. And the effect of reducing speckle noise is easily obtained.

  In addition, an increase in the wavelength difference between the elements also decreases the pitch between the elements required to obtain different speckle patterns, so that further miniaturization can be expected depending on the system. In addition, even when the pitch between the elements is maintained, the same speckle reduction effect can be obtained even when the overall wavelength difference Δλ (λ1−λ5) is narrowed, so that the light emitting element forms a structure for emitting light of different wavelengths. Becomes easier.

  Also in the second embodiment, by integrating light emitting elements having different oscillation wavelengths in the plane of the VCSEL light source, it is possible to reduce speckle noise without increasing the size of the light emitting unit and increasing the cost. Is obtained. Further, since lasers having different wavelengths are used, it is not always necessary to satisfy the condition 2 at the time of a single wavelength, and the restrictions on the layout are relaxed. Therefore, since each light emitting element can be provided at a smaller interval than in the case of multiple light source angle multiplexing, the integration density can be improved. With the increase in integration density, further effects can be expected, such as downsizing of the chip and the increase in the degree of freedom in designing because an extra area can be used.

(Example 3)
FIG. 10 is a diagram showing a modification of the configuration of the VCSEL array 11. The VCSEL array 11 illustrated in FIG. 10 includes at least one light emitting element group a1 called a layer that is controlled so that a plurality of light emitting elements emit light at the same time. FIG. 10 shows a configuration in which the light emitting element groups a1 are arranged one-dimensionally, but a configuration in which the light emitting element groups a1 are two-dimensionally arranged may be used. The light emission timing of each layer 222 is independently controlled.

  In the layer 222 shown in FIG. 10, five light emitting elements a2 are arranged in a cross shape. Each light emitting element a2 is controlled to emit light at the same timing in the same layer 222.

  The pitch A of each layer 222 and the pitch (pitch B and pitch C) of each light emitting element a2 shown in FIG. 10 are set based on the conditions 1 and 2 of the inter-element pitch of the first embodiment. When the oscillation wavelength of each light emitting element is made different, the light source of the second embodiment is applied.

  Note that here, five light-emitting elements a2 of the layer 222 are arranged in a cross shape, but the present invention is not limited to this. The number of light emitting elements a2 may be increased or decreased, or more light emitting elements a2 may be arranged in a layout such as a honeycomb structure.

  Although the opening of the light emitting element a2 is shown as a square, the opening may be another shape such as a hexagon.

(Second embodiment)
A projection device including the surface emitting semiconductor laser according to the first embodiment will be described.
FIG. 11 is a diagram illustrating an example of a configuration of a projection device according to the second embodiment. The projection apparatus 10 shown in FIG. 11 has a VCSEL array 11, an optical system 12, and a light deflecting element 13.

  The optical system 12 includes a lens, and guides light emitted from each light emitting element of the VCSEL array 11 to the light deflecting element 13.

  The light deflecting element 13 projects the projection light 14 onto the target 15 by projecting light from the optical system 12 onto a projection area.

  The projection light 14 shown in FIG. 11 is a light in which the respective emitted lights of the respective light emitting elements a of the VCSEL array 11 are overlapped, deflected on the mirror surface of the light deflecting element 13, and projected onto the object 15. Also in the second embodiment, the effect of speckle noise reduction can be obtained by projecting the projection light 14 onto an assumed projection area.

(Light deflection element)
The light deflecting element 13 is a movable mirror that can scan a laser beam in one or two axes. The movable mirror includes, for example, a MEMS (Micro Electro Mechanical Systems) mirror, a polygon mirror, a galvano mirror, and the like. However, as long as it can scan laser light in one axis or two axes, another method is used. May be used. In this embodiment, a movable mirror that uniaxially scans the line light 14 formed by the optical system 12 on the measurement target 15 in the scanning range is used. The movable mirror optically scans the line light to form a two-dimensional planar projection pattern.

  FIG. 12 is a diagram illustrating an example of a configuration of a MEMS mirror (also referred to as a MEMS mirror scanner) that is an example of the light deflecting element 13. The MEMS mirror scanner shown in FIG. 12 has a movable portion 132 and two sets of meandering beam portions 133 on a support substrate 131.

  The movable section 132 includes a reflection mirror 1320. One end of each of the two sets of meandering beam portions 133 is connected to the movable portion 132, and the other end is supported by the support substrate 131. The two sets of meandering beam portions 133 each include a plurality of meandering beam portions, and both of them have a first piezoelectric member 1331 deformed by applying a first voltage and a second piezoelectric member 1331 deformed by applying a second voltage. And every other one of the piezoelectric members 1332 in each beam portion. The first piezoelectric member 1331 and the second piezoelectric member 1332 are provided independently for each adjacent beam portion. The two sets of meandering beam parts 133 are deformed by applying a voltage to the first piezoelectric member 1331 and the second piezoelectric member 1332, respectively, and rotate the reflection mirror 1320 of the movable part 132 around the rotation axis.

  Specifically, voltages having opposite phases are applied to the first piezoelectric member 1331 and the second piezoelectric member 1332 to cause each beam portion to warp. As a result, the adjacent beam portions bend in different directions, which are accumulated, and the reflecting mirror 1320 reciprocates around the rotation axis together with the movable portion 132 connected to the two meandering beam portions 133. Furthermore, by applying a sine wave having a drive frequency matching the mirror resonance mode with the rotation axis as the rotation center to the first piezoelectric member 1331 and the second piezoelectric member 1332 in opposite phases, a very low voltage and very low voltage can be obtained. A large rotation angle can be obtained.

  The drive waveform is not limited to a sine wave. For example, a sawtooth wave may be used. Further, the drive may be performed not only in the resonance mode but also in a non-resonance mode.

  The light deflecting element 13 is not limited to the MEMS mirror, but may be any movable member having a reflecting portion for scanning light, such as a polygon mirror or a galvanometer mirror. According to the MEMS mirror, it is advantageous in miniaturization and weight reduction. The drive system of the MEMS mirror may be any of an electrostatic system, a piezoelectric system, an electromagnetic system, and the like.

(Third embodiment)
1 shows an example in which a surface emitting semiconductor laser according to a first embodiment is applied to a measuring device. Here, an example of application to a three-dimensional measurement device that measures a measurement target will be described as an example of the measurement device.

  FIG. 13 is a diagram illustrating an example of a measurement device according to the third embodiment. The measurement device 1 illustrated in FIG. 13 includes a measurement information acquisition unit 20 and a control unit 30.

  The measurement information acquisition unit 20 includes a projection device 10 as a projection unit and a camera 21 as an imaging unit. The projection device 10 has a VCSEL array 11, an optical system 12, and a light deflecting element 13. Under the control of the control unit 31 of the control unit 30, the measurement information acquisition unit 20 deflects the light of the plurality of light emitting elements a of the VCSEL array 11 by the light deflecting element 13 and projects the light on the measurement area. The control unit 31 projects the projection light 14 having a predetermined pattern on the entire measurement area by adjusting the luminance and the lighting timing of each light emitting element a of the VCSEL array 11. For example, by controlling lighting and extinguishing (on / off) of the light emitting element a, the projection light 14 of a desired projection pattern such as a black and white gray code pattern is projected.

  The position and angle of the camera 21 are fixed such that the projection center 300 of the projection light 14 projected onto the measurement target by the projection device 10 is the center of the imaging region 40. Thereby, the camera 21 captures an image of the projection area.

  The camera 21 has a lens 210 and an image sensor 211. As the imaging element 211, for example, a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) image sensor is used. The light incident on the camera 21 forms an image on the image sensor 211 via the lens 210 and is photoelectrically converted. The electric signal photoelectrically converted by the image sensor 211 is converted into an image signal, and the image signal is output from the camera 21 to the arithmetic processing unit 32 of the control unit 30.

  The control unit 30 performs control of projection of pattern light by the projection device 10 and control of imaging by the camera 21, and performs arithmetic processing such as three-dimensional measurement of a measurement target based on an image signal captured by the camera 21. The control unit 31 may perform control to switch the pattern light projected by the projection device 10 to another pattern light. Further, the control unit 31 may perform control for outputting the calibration information used by the arithmetic processing unit 32 to calculate the three-dimensional coordinates.

  The control unit 30 has an arithmetic processing unit 32 as a measuring unit. The arithmetic processing unit 32 calculates (measures) three-dimensional coordinates based on the input image signal, and acquires a three-dimensional shape. Further, the arithmetic processing unit 32 outputs three-dimensional shape information indicating the calculated three-dimensional shape to a PC or the like (not shown) according to an instruction from the control unit 31. Although FIG. 13 shows a configuration in which one set of measurement information acquisition units 20 is attached to the control unit 30, a plurality of sets of measurement information acquisition units 20 may be attached to the control unit 30.

(Explanation of the function block of the control unit)
FIG. 14 is a diagram illustrating an example of a block configuration of the measuring device 1. In FIG. 14, the same reference numerals are given to portions that have already been described, and detailed description thereof will be omitted as appropriate.

  The arithmetic processing unit 32 shown in FIG. 14 analyzes the image signal output from the camera 21. The arithmetic processing unit 32 performs a three-dimensional information restoring process by an arithmetic process using the analysis result of the image signal and the calibration information, and thereby performs three-dimensional measurement of the target. The arithmetic processing unit 32 supplies the restored three-dimensional information to the control unit 31.

  The control unit 31 includes a system control unit 310, a pattern storage unit 311, a light source driving / detecting unit 312, an optical scanning driving / detecting unit 313, and an imaging control unit 314.

  The optical scanning drive / detection unit 313 drives the light deflection element 13 under the control of the system control unit 310. The system control unit 310 controls the optical scanning drive / detection unit 313 so that the light irradiated to the center of deflection of the light deflection element 13 irradiates the measurement target. The imaging control unit 314 controls the imaging timing and the exposure amount of the camera 21 under the control of the system control unit 310.

  The light source driving / detecting unit 312 controls turning on and off of each light emitting element of the VCSEL array 11 under the control of the system control unit 310.

  The pattern storage unit 311 reads, for example, pattern information of a projection image stored in a non-volatile storage medium of the measurement device 1. The pattern information is pattern information for forming a projection image (projection pattern). The pattern storage unit 311 reads pattern information according to an instruction from the system control unit 310 and transfers the pattern information to the system control unit 310. The system control unit 310 controls the light source drive / detection unit 312 based on the pattern information passed from the pattern storage unit 311.

  The system control unit 310 instructs the pattern storage unit 311 to read out the pattern information based on the restored three-dimensional information supplied from the arithmetic processing unit 32. The system control unit 310 controls the light source drive / detection unit 312 according to the pattern information read by the pattern storage unit 311.

  Further, the system control unit 310 instructs the calculation processing unit 32 on a calculation method according to the read pattern information.

  The arithmetic processing unit 32, the system control unit 310, and the imaging control unit 314 are realized by a measurement program that operates on a CPU (Central Processing Unit). Specifically, the CPU implements the arithmetic processing unit 32, the system control unit 310, and the imaging control unit 314 by reading and executing a measurement program from a ROM (Read Only Memory). Note that this implementation method is an example, and the present invention is not limited to this. For example, a part or all of the arithmetic processing unit 32, the system control unit 310, and the imaging control unit 314 may be configured by hardware circuits operating in cooperation with each other. In addition, not only the arithmetic processing unit 32, the system control unit 310, and the imaging control unit 314, but also other blocks may be realized by a measurement program.

  In the third embodiment, each setting of the measurement device is set as “a setting having an effect of reducing speckle noise”. For this reason, spec noise is reduced in an image obtained by capturing the measurement target, and measurement accuracy when analyzing luminance information of the captured image is improved.

(Fourth embodiment)
Next, a fourth embodiment will be described. The fourth embodiment is an example in which the measuring device 1 according to the third embodiment is used in combination with a robot arm (articulated arm).

  FIG. 15 is a diagram illustrating an example of a configuration of a robot according to the fourth embodiment. FIG. 15 shows an example in which the measuring device 1 is applied to a robot arm having multiple joints. The robot arm 70 includes a hand unit 71 for picking an object, and the measuring device 1 is mounted immediately near the hand unit 71. The robot arm 70 includes a plurality of bendable movable units, and changes the position and the orientation of the hand unit 71 according to the control.

  The measuring device 1 is provided so that the projection direction of the light coincides with the direction in which the hand unit 71 faces, and measures the picking target 15 of the hand unit 71 as a measurement target.

  As described above, in the fourth embodiment, by mounting the measuring device 1 on the robot arm 70, the object to be picked can be measured from a short distance, and compared with the measurement from a distance using a camera or the like. Measurement accuracy can be improved. For example, in the field of factory automation (FA) in various assembly lines in factories, robots such as the robot arm 70 are used for inspection and recognition of parts. By mounting the measuring device 1 on the robot, it is possible to accurately inspect and recognize components.

(Fifth embodiment)
Next, a fifth embodiment will be described. The fifth embodiment is an example in which the measuring device 1 according to the third embodiment is mounted on an electronic device such as a smartphone or a PC and used.

  FIG. 16 is a diagram illustrating an example of a configuration of an electronic device such as a smartphone according to the fourth embodiment. An example in which the measuring device 1 is applied to a smartphone 80 is shown. The smartphone 80 has the measuring device 1 and a user authentication function. The user authentication function is provided, for example, by dedicated hardware. Note that the “authentication function unit” is not limited to dedicated hardware, and may be provided so that a CPU of a computer executes a program such as a ROM to realize this function. The measuring device 1 measures the shape of the user's 81 face, ears and head. Based on the measurement result, the user authentication function determines whether the user 81 is a person registered in the smartphone 80.

  As described above, in the fifth embodiment, by mounting the measuring device 1 on the smartphone 80, the shape of the face, ears, and head of the user 81 can be measured with high accuracy, and the recognition accuracy can be improved. Improvement can be achieved. In the present embodiment, the measuring device 1 is mounted on the smartphone 80, but may be mounted on an electronic device such as a PC or a printer. Also, the functional aspect is not limited to the personal authentication function, and may be used for a face shape scanner or the like.

(Sixth embodiment)
Next, a sixth embodiment will be described. The sixth embodiment is an example in which the measuring device 1 according to the third embodiment is mounted on a moving body and used.

  FIG. 17 is a diagram illustrating an example of a configuration of a vehicle according to the sixth embodiment. 1 shows an example in which a measuring device 1 is applied to an automobile. The measuring device 1 and a driving support function are mounted in the vehicle interior 85. The driving support function is provided, for example, by dedicated hardware. Note that the “drive support unit” is not limited to dedicated hardware, and the CPU of a computer configuration may execute this program by executing a program such as a ROM. The measurement device 1 measures the face, posture, and the like of the driver 86. Based on the measurement result, the driving support function provides appropriate support according to the situation of the driver 86.

  As described above, in the sixth embodiment, by mounting the measuring device 1 on an automobile, the face, posture, and the like of the driver 86 can be measured with high accuracy. Improvement can be achieved. In the present embodiment, the measuring device 1 is mounted on an automobile. However, the measuring device 1 may be mounted on a train or in a cockpit (or passenger seat) of an airplane. Further, the functional aspect is not limited to the recognition of the driver's 86 state, such as the face and posture of the driver 86, but may be used for recognition of a passenger other than the driver 86 or the state of the interior 85 of the vehicle. Further, the present invention may be used for vehicle security such as performing personal authentication of the driver 86 and determining whether or not the driver 86 is registered as a vehicle driver in advance.

  FIG. 18 is a diagram illustrating an example of a configuration of another moving object according to the sixth embodiment. FIG. 18 illustrates an example in which the measurement device 1 is applied to an autonomous mobile body. The measuring device 1 is mounted on the moving body 87 and measures around the moving body 87. Based on the measurement result, the moving body 87 determines its own moving route and calculates the layout of the room 89 such as the position of the desk 88.

  As described above, in the sixth embodiment, by mounting the measuring device 1 on the moving body 87, the periphery of the moving body 87 can be measured with high accuracy, and the driving of the moving body 87 can be supported. In the present embodiment, the measuring device 1 is mounted on a small moving body 87, but may be mounted on an automobile or the like. Further, it may be used not only indoors but also outdoors, and may be used for measuring a building or the like.

(Seventh embodiment)
Next, a seventh embodiment will be described. The seventh embodiment is an example in which the measuring device 1 according to the third embodiment is mounted on a modeling device and used.

  FIG. 19 is a diagram illustrating an example of a configuration of a modeling apparatus according to the seventh embodiment. FIG. 19 shows an example in which the measuring device 1 is applied to a head unit 91 of a 3D printer 90 which is an example of a modeling device. The head unit 91 is an example of a “head”, and has a nozzle 93 that discharges a modeling liquid for forming the formed object 92. The measuring device 1 measures the shape of the formation 92 formed by the 3D printer 90 during the formation. The formation control of the 3D printer 90 is performed based on the measurement result.

  As described above, in the seventh embodiment, by mounting the measuring device 1 on the 3D printer 90, the shape of the formed object 92 can be measured during formation, and the formed object 92 can be formed with high accuracy. In the present embodiment, the measuring device 1 is mounted on the head unit 91 of the 3D printer 90, but may be mounted at another position in the 3D printer 90.

11 VCSEL array a Light emitting element D Pitch (element interval)
LWD distance θ angle

JP 2009-146941 A

Claims (14)

Having a plurality of light emitting elements in the plane,
The element arrangement of the plurality of light emitting elements,
In the assumed projection area, the irradiation light of the plurality of light emitting elements satisfies the element interval where they overlap, and the speckle pattern of each irradiation light obtained in the assumed projection area satisfies the different element distance for each irradiation light. And light source. The element arrangement of the plurality of light emitting elements,
The speckle contrast obtained in the assumed projection area with the increase in the number of lighting of the light emitting elements satisfies the element interval that follows the theoretical value curve of the speckle contrast obtained when different speckle patterns overlap. The light source according to claim 1, wherein: The light source according to claim 1, further comprising the light emitting elements having different oscillation wavelengths in the plane. The light source according to claim 3, comprising a plurality of light emitting elements having the same oscillation wavelength in the plane. 5. The light source according to claim 4, wherein an element interval between light-emitting elements having different oscillation wavelengths in the plane is smaller than an element interval between light-emitting elements having the same oscillation wavelength. 8.   The light source according to claim 5, wherein the light emitting elements of the respective oscillation wavelengths are arranged at the same element interval. A light emitting element group including at least one light emitting element of each oscillation wavelength is a minimum unit, and a plurality of light emitting element groups of the minimum unit are arranged such that light emitting elements of the same oscillation wavelength take a periodic position. The light source according to any one of claims 4 to 6, wherein: A light source according to any one of claims 1 to 7,
An optical system for guiding the light of each light emitting element of the light source,
A light deflecting element that reflects light guided by the optical system to the projection area,
A projection device comprising: A projection device according to claim 8,
Imaging means for imaging the projection area;
A measurement unit that measures a measurement target in the projection area based on information captured by the imaging unit;
A measuring device comprising: A measuring device according to claim 9,
An articulated arm equipped with the measuring device,
A robot comprising: A measuring device according to claim 9,
An authentication unit that authenticates a user based on a measurement result of the user by the measurement device,
An electronic device comprising: A measuring device according to claim 9,
A driving support unit that supports driving of the moving object based on the measurement result by the measurement device,
A moving object comprising: A measuring device according to claim 9,
A head that forms a product based on a measurement result by the measurement device,
A shaping apparatus comprising: A light source having a plurality of surface light emitting elements,
The element arrangement of the plurality of surface light-emitting elements is, among the plurality of surface light-emitting elements, at least an element interval at which irradiation light of an adjacent surface light-emitting element overlaps, and a speckle pattern in an irradiation area of the irradiation light. The light source, wherein the element interval is set so as to be different for each irradiation light.