Optical system device and mobile object

Abstract

The purpose of the present invention is to provide an optical system device capable of irradiation with light in which the light intensity and irradiation angle are adjusted.　The optical system device is characterized by comprising: a light irradiation means 11 that is capable of irradiation with light; and a plurality of optical elements 12 that control the light from the light irradiation means 11 and perform irradiation at a prescribed irradiation angle, wherein at least two of the optical elements 12 differ in irradiation angle. When an optical axis direction of the light irradiation means 11 is a z direction, a direction perpendicular to the optical axis is an x direction, and the optical elements 12 are sequentially assigned with numbers in descending order of the irradiation angles in the x direction, the i-th (i being a natural number) optical element 12 preferably satisfies the formula, wherein Wxi is an irradiation width in the x direction at a position where the illuminance of the irradiation light from the optical element 12 is a prescribed E, and Wxavg is an average value of the irradiation widths of the optical elements 12.

Description

Optical system device and moving body

[0001] The present invention relates to an optical system device and a moving body provided with the optical system device.

[0002] A three-dimensional measurement sensor using the time-of-flight (TOF) method is being adopted for portable devices, vehicles, robots, etc. This measures the distance of an object from the time it takes for the light irradiated from a light source to be reflected back after being reflected by the object. If the light from the light source irradiates a predetermined region 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 above sensor system includes a light emitting unit that irradiates an object with light, and a light receiving unit that receives the light reflected from each point of the object by an imaging means such as a camera, and calculates the distance of the object by an arithmetic means from the signal received by the imaging means.

[0004] Since the imaging means and arithmetic means of the light receiving unit can use existing CMOS imagers and CPUs, the unique part of the above system is the light emitting unit. The light emitting unit includes a light irradiation means capable of irradiating light such as a laser, and an optical element such as a microlens array that controls the light from the light irradiation means and irradiates it at a predetermined irradiation angle.

[0005] For example, an optical element and an optical system device capable of irradiating light with a high-contrast dot pattern are known (for example, Patent Document 1).

[0006] International Publication No. 2023 / 026987

[0007] Conventionally, when measuring the position and shape of an object using such an optical system device, the light emitting unit used irradiates light at a predetermined irradiation angle with a constant light intensity. However, for example, when measuring an object on the road with an in-vehicle TOF sensor, when close to the vehicle, the light intensity may be small, so a wide irradiation angle is required. On the other hand, when far from the vehicle, a narrow irradiation angle is sufficient, so a large light intensity is required. Thus, in the conventional optical system device, the light intensity and irradiation angle are not considered, and it is not possible to irradiate light with the light intensity and irradiation angle adjusted at close and far distances.

[0008] Therefore, the present invention aims to provide an optical system capable of emitting light with adjustable light intensity and irradiation angle, and a mobile body equipped with the optical system.

[0009] To achieve the above objective, the optical system of the present invention comprises a light irradiation means capable of irradiating light, and a plurality of optical elements that control the light from the light irradiation means and irradiate it at a predetermined irradiation angle, wherein at least two or more of the optical elements have different irradiation angles.

[0010] In this case, if the optical axis direction of the light irradiation means is the z direction, and the direction perpendicular to the optical axis is the x direction, and the optical elements are arranged in order from the largest irradiation angle in the x direction, then for the i-th optical element (where i is a natural number), if the irradiation width in the x direction at the position where the illuminance of the light irradiated by the optical element is a predetermined E is Wxi, and the average value of the irradiation width of each optical element is Wxavg, then the following equation It is preferable to satisfy the following conditions.

[0011] Furthermore, if we define the direction perpendicular to the z and x directions as the y direction, and for the i-th optical element (where i is a natural number), if we define the irradiation width in the y direction at the position where the illuminance of the light irradiated by the optical element is a predetermined E as Wyi, and the average value of the irradiation widths of each optical element as Wyavg, then the following equation It is preferable to satisfy the following conditions.

[0012] Furthermore, the light irradiation means may selectively irradiate the plurality of optical elements with light.

[0013] In this case, it is preferable to include a control unit that controls the illumination of the light irradiation means.

[0014] It may also include an imaging unit that detects information about the received light.

[0015] The system may also include a calculation unit that calculates the distance to an object based on information from the imaging unit.

[0016] Furthermore, the mobile body of the present invention is a mobile body with a width in the x direction Tx, and is equipped with the optical system of the present invention, and is characterized in that Tx = Wxavg.

[0017] Furthermore, the mobile body of the present invention is a mobile body with a width in the y direction Ty, equipped with the optical system of the present invention, and characterized in that Ty = Wyavg.

[0018] The optical system of the present invention can emit light with adjusted illuminance and irradiation angle.

[0019] This is a schematic plan view showing an optical system according to the present invention. This is a schematic side view showing an optical system according to the present invention. This is a schematic plan view showing an optical system according to the present invention. This is a schematic plan view showing an example of an optical system according to the present invention. This is a schematic side view showing an optical system according to the present invention. This is a schematic plan view showing another optical system according to the present invention.

[0020] The optical system 100 of the present invention will be described below. As shown in Figure 1, the optical system 100 of the present invention has a light-emitting unit 1 which is composed of a light irradiation means 11 capable of irradiating light and a plurality of optical elements 12 that control the light from the light irradiation means 11 and irradiate it at a predetermined irradiation angle.

[0021] The light irradiation means 11 is for irradiating light. The light irradiation means 11 can be any device capable of irradiating the light necessary for the purpose. Specific examples of the light irradiation means 11 include, for example, LEDs and VCSELs (Vertical Cavity Surface Emitting Lasers) that can be expected to produce high output with low power consumption. VCSELs include single-emitter VCSELs that have one light source capable of irradiating light perpendicular to the light-emitting surface, and multi-emitter VCSELs that have multiple light sources. The light irradiation means 11 may also consist of multiple LEDs or VCSELs. The wavelength of the light irradiated by the light irradiation means 11 can be appropriately determined depending on the purpose for which the optical system 100 is to measure, but considering safety and other factors, it is preferable to use light with a longer wavelength than visible light, such as infrared light.

[0022] Furthermore, the light irradiation means 11 may irradiate multiple optical elements 12 simultaneously, as shown in Figure 1(a), or it may selectively irradiate each optical element 12, as shown in Figure 1(b). In this case, multiple light irradiation means 11 corresponding to each optical element 12 can be arranged. It is preferable that each light irradiation means 11 irradiates only the corresponding optical element 12. In addition, each light irradiation means 11 may emit light of a different wavelength. This makes it possible to distinguish the emitted light by wavelength.

[0023] The optical element 12 controls the light from the light irradiation means 11 and irradiates it at a predetermined irradiation angle. Furthermore, two or more of the optical elements 12 are designed to have different irradiation angles. The optical element 12 consists of, for example, a first surface on which the light from the light irradiation means 11 is incident and a second surface on which the controlled light is emitted. The optical element 12 also has an uneven shape 121 on at least one or both of the first and second surfaces that exhibits an optical function. The uneven shape 121 can be any shape that controls the light from the light irradiation means 11 and irradiates it at a predetermined irradiation angle. Furthermore, the optical element 12 can control how it irradiates the light emitted by the light irradiation means 11 into the irradiation area within the irradiation angle, for example, it can irradiate the entire irradiation area, irradiate in a dot pattern, irradiate in a line pattern, etc.

[0024] The material for the optical element 12 can be any material that can transmit light of at least the wavelength irradiated by the light irradiation means 11, but for example, silicon resins, epoxy resins, acrylic resins, etc., can be used. For example, polydimethylsiloxane (PDMS) is an example of a silicon resin. It is also possible to use glass as the material for the optical element 12. Furthermore, the optical element 12 can be manufactured in any way, for example, by conventionally known methods such as imprinting or injection molding.

[0025] Here, the direction of the optical axis of the light irradiation means 11 is defined as the z direction, and the direction perpendicular to the z direction is defined as the x direction. At this time, as shown in Figure 3, when the optical elements 12 are arranged in order from the largest irradiation angle in the x direction, if the irradiation width in the x direction at the position where the illuminance of the light irradiated by the i-th optical element 12 (i is a natural number) is a predetermined value E is Wxi, and the average value of the irradiation widths of each optical element 12 is Wxavg, then the following equation It is preferable to satisfy the following conditions. Here, the illuminance E of the light may be based on the average illuminance of the light irradiated onto a plane perpendicular to the z direction, or on the illuminance on the optical axis. Alternatively, if θxi is the irradiation angle in the xz plane on the optical axis of the optical element 12, and Li is the distance in the z direction from the optical element 12 at the position where the illuminance of the light irradiated by the optical element 12 is E, then Wxi may be calculated from the following formula. Furthermore, if the number of optical elements 12 is n, Wxavg can also be calculated from the above formula using the following formula.

[0026] This allows for irradiating an area with a width of 0.9 Wxavg to 1.1 Wxavg with light of roughly the same illuminance, even if the irradiation angle in the x-direction is wide near the optical element 12 and narrowed at a distance. Furthermore, the light from each optical element 12 can be efficiently delivered within a width of 0.9 Wxavg to 1.1 Wxavg. In addition, since light is not irradiated into unnecessary areas, noise such as multipath interference can be prevented. Here, the width Wxavg can be set appropriately according to the purpose of the optical system. For example, as shown in Figure 4, when used to ensure the safety of a moving object such as an automobile, if the direction of travel of the moving object is the z-direction and the horizontal direction perpendicular to the z-direction is the x-direction, the width Wxavg can be set based on the width of the moving object. Specifically, if the width of the moving object is Tx, then Tx = Wxavg or Tx = 0.9 Wxavg can be used.

[0027] Furthermore, the direction of the optical axis of the light irradiation means 11 is defined as the z direction, the direction perpendicular to the z direction is defined as the x direction, and the direction perpendicular to both the z and x directions is defined as the y direction. In this case, as shown in Figure 5, when the optical elements 12 are arranged in order from the largest irradiation angle in the y direction, if the irradiation width in the y direction at the position where the illuminance of the light irradiated by the i-th optical element 12 (where i is a natural number) is a predetermined value E is defined as Wyi, and the average value of the irradiation width of each light-emitting part is defined as Wyavg, then the following equation It is preferable to satisfy the following conditions. Here, if θyi is the irradiation angle in the yz plane on the optical axis of the optical element 12, and Li is the distance in the z direction from the optical element 12 at the position where the illuminance of the light irradiated by the optical element 12 is E, then Wyi may be calculated from the following formula. Furthermore, if the number of optical elements 12 is n, Wyavg can also be calculated from the above formula using the following formula.

[0028] As a result, even if the illumination angle in the y-direction is widened near the optical element 12 and narrowed at a distance, light of similar illuminance can be irradiated over a width of 0.9 Wyavg to 1.1 Wyavg. Furthermore, the light from each optical element 12 can be efficiently delivered over a width of 0.9 Wyavg to 1.1 Wyavg. In addition, since light is not irradiated into unnecessary areas, noise such as multipath interference can be prevented. Here, the width Wyavg can be set appropriately according to the purpose of the optical system. For example, when used to ensure the safety of a moving object such as an automobile, if the direction of travel of the moving object is the z-direction, the horizontal direction perpendicular to the z-direction is the x-direction, and the direction perpendicular to both the z-direction and the x-direction is the y-direction, then the width Wyavg can be set based on the height of the moving object. Specifically, if the height of the moving object is Ty, then Ty = Wyavg or Ty = 0.9 Wyavg can be used.

[0029] Furthermore, the optical system of the present invention may also include a control unit 2 that controls the illumination of the light irradiation means 11. The control unit 2 is, for example, electrically connected to the light irradiation means 11 and controls the ON / OFF state of the light emitted by the light irradiation means 11, as well as the change in light intensity. If the light irradiation means 11 has multiple light sources, it is also possible to control the ON / OFF state of the light and the change in light intensity of only some of the light sources. Moreover, if there are multiple light irradiation means 11, it is also possible to control the ON / OFF state of each light irradiation means 11. This makes it possible to illuminate multiple light irradiation means 11 sequentially or simultaneously. Furthermore, if the illumination of the light irradiation means 11 corresponding to each optical element 12 can be controlled, the light irradiation means can selectively irradiate multiple optical elements with light. The control unit 2 can be anything that can control the light emitted by the light irradiation means 11, but existing control devices such as a CPU or computer can be used, for example.

[0030] Furthermore, the optical system of the present invention may also include an imaging unit 3 for detecting information about the received light, as shown in Figure 6. The imaging unit 3 detects the light reflected back by an object 9 from the light emitted from the light-emitting unit 1 and converts information such as its position and light intensity into digital data. If multiple light irradiation means 11 each emit light of different wavelengths, any unit capable of detecting the wavelength of light used should be used. Such an imaging unit 3 can be anything that can detect reflected light and convert the information into digital data; for example, existing image sensors such as CMOS or CCD can be used. Also, the imaging unit 3, together with the light irradiation means 11 described above, may all be formed on the same semiconductor chip. Note that the object 9 can be anything that can be imaged by the imaging unit 3, and various objects are applicable depending on the measurement purpose of the optical system. For example, if the purpose is to prevent collisions when a car is moving, the object 9 could be other cars, motorcycles, bicycles, pedestrians, animals, utility poles, walls, curbs, etc.

[0031] Furthermore, as shown in Figure 6, the optical system of the present invention may further include a calculation unit 4 that calculates the distance to the object 9 based on information from the imaging unit 3. The calculation unit 4 is for calculating the distance to the object 9 based on information from the imaging unit 3. Here, the distance to the object 9 means the distance between the object 9 and a reference object such as the light irradiation means 11, the optical element 12, or the imaging unit 3. The calculation unit 4 may calculate the distance to the object 9 in any way, but for example, the distance between the optical element 12 and the object 9 can be calculated from the time it takes for the light irradiated from the optical element 12 to be reflected by the object 9 and received by the imaging unit 3. Also, if the light irradiated from the optical element 12 is dot-shaped or line-shaped, it is also possible to calculate the distance between the optical element 12 and the object 9 using triangulation from the change in the position of the dot or line. In addition, the presence or absence of reflected light and the light intensity of the light irradiated from each optical element 12 to the object 9 are different. Therefore, it is also possible to calculate the distance from the presence or absence of light and the light intensity that can be detected by the imaging unit 3. The distance between the optical element 12 and the object 9 calculated in this way can be used in various technologies, such as 3D measurement and autofocus.

[0032] Such an optical system of the present invention can be installed in a moving body such as an automobile, and can be used, for example, to ensure safety when a moving body such as an automobile is in motion, as described above.

[0033] 2 Control unit 3 Imaging unit 4 Calculation unit 9 Object 11 Light irradiation means 12 Optical element 100 Optical system

Claims

1. An optical system comprising: a light irradiation means capable of irradiating light; and a plurality of optical elements that control the light from the light irradiation means and irradiate it at a predetermined irradiation angle, wherein at least two or more of the optical elements have different irradiation angles.

2. Let the direction of the optical axis of the light irradiation means be the z direction, and the direction perpendicular to the optical axis be the x direction. When the optical elements are arranged in order from the largest irradiation angle in the x direction, if the irradiation width in the x direction at the position where the illuminance of the light irradiated by the i-th optical element (where i is a natural number) is a predetermined E is Wxi, and the average value of the irradiation widths of each optical element is Wxavg, then the following equation The optical system according to claim 1, characterized in that it satisfies the following conditions.

3. Let the direction perpendicular to the z and x directions be the y direction. For the i-th optical element (where i is a natural number), let Wyi be the illumination width in the y direction at the position where the illuminance of the light emitted by the optical element is a predetermined E. Let Wyavg be the average value of the illumination widths of each optical element. Then, the following equation The optical system according to claim 2, characterized in that it satisfies the following conditions.

4. The optical system according to any one of claims 1 to 3, characterized in that the light irradiation means selectively irradiates the plurality of optical elements with light.

5. The optical system according to claim 4, further comprising a control unit for controlling the illumination of the light irradiation means.

6. The optical system according to any one of claims 1 to 3, characterized by comprising an imaging unit for detecting information of received light.

7. The optical system according to any one of claims 1 to 3, further comprising a calculation unit that calculates the distance of an object based on information from the imaging unit.

8. A mobile body having a width in the x-direction Tx, comprising the optical system described in claim 2, and characterized in that Tx = Wxavg.

9. A moving body having a width in the y direction Ty, comprising the optical system described in claim 3, and characterized in that Ty = Wyavg.

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