Range imaging device

Abstract

To provide a distance image pickup device capable of efficiently dissipating heat while ensuring watertightness inside. [Solution] The distance image capturing device includes an imaging section having a VCSEL (42), an optical unit, and an imaging element, a main board that controls the imaging section, and a metal housing (10) that houses the imaging section and the main board. The imaging section has a light source board (41) on which the VCSEL (42) is attached, an element board (55) on which the imaging element is attached, and a metal support block (60) that is thermally connected to the housing and supports the optical unit from below, and the light source board and element board are thermally connected to the support block.

Description

[Technical Field]

[0001] The present invention relates to a distance imaging device. [Background technology]

[0002] 2. Description of the Related Art Imaging devices equipped with a light source are known, and a typical example of the use of the light source is a flash used for taking pictures in dark places. A distance image capturing device, which is a type of imaging device, uses an imaging element to acquire a distance image based on the light reflected by the target object when reference light is irradiated from a light source, and measures the distance to the object using a predetermined processing method such as the time-of-flight (TOF) method.

[0003] Light sources generate heat when they emit light, and reach high temperatures. Furthermore, in imaging devices, the imaging elements also generate heat when driven. If the internal temperature becomes too high due to this heat generation, it can cause malfunctions. In relation to this problem, Patent Document 1 describes an imaging device that includes a duct with a first intake port through which outside air can flow in, and a centrifugal fan that forcibly flows the outside air from the first intake port into the duct. By using the centrifugal fan to forcibly flow the outside air into the duct that is thermally connected to the heat-generating body, efficient heat dissipation is possible. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2024-136476 Summary of the Invention [Problem to be solved by the invention]

[0005] Since range imaging devices are often installed in harsh environments such as factories, it is necessary to ensure that the interior is watertight. Therefore, it is difficult to apply the technology of Patent Document 1, which requires the installation of an air intake. On the other hand, as will be described in more detail below, there are other situations in which distance imaging devices are prone to high temperatures, so there is a need for more efficient heat dissipation than in general imaging devices equipped with a flash light source.

[0006] In view of the above circumstances, an object of the present invention is to provide a range image pickup device that is capable of efficiently dissipating heat while ensuring watertightness inside. [Means for solving the problem]

[0007] The present invention is a distance imaging device that includes an imaging unit having a light source, an optical unit, and an imaging element, a main board that controls the imaging unit, and a metal housing that houses the imaging unit and main board inside. The imaging unit has a light source board on which a light source is attached, an element board on which an imaging element is attached, and a metal support block that is thermally connected to the housing and supports the optical unit from below, and the light source board and element board are thermally connected to the support block. The element substrate has columnar thermal wiring exposed on the surface opposite to the side on which the imaging element is arranged, and the imaging element and the housing are thermally connected via the thermal wiring. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a range image pickup device that is capable of efficiently dissipating heat while ensuring watertightness inside. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view showing a camera according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram showing the general configuration of the camera. [Figure 3] FIG. [Figure 4] FIG. 2 is an exploded view showing the imaging unit of the camera. [Figure 5] FIG. 2 is a rear view of the light source board of the imaging unit. [Figure 6] FIG. 2 is a diagram showing the imaging unit in one cross section. [Figure 7]7 is a diagram showing the same imaging unit at a cross section different from that in FIG. 6. [Figure 8] 10A and 10B are diagrams showing modified examples of the element substrate of the imaging unit. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of the present invention will be described with reference to FIGS. 1 is a perspective view showing a camera 1, which is a distance imaging device according to this embodiment. The camera 1 has a rectangular parallelepiped shape defined by a metal housing 10. Housing 10 has, on its front side, a first opening 2 for imaging and a second opening 3 for a light source that irradiates reference light. Two second openings 3 are provided, one on either side of first opening 2.

[0011] 2 is a schematic diagram showing the overall configuration of the camera 1. Inside the housing 10, a power supply board 20, a main board 30, and an imaging unit 40 are arranged. The power supply board 20 is connected to the power supply Es and generates voltages for driving the various components of the camera 1. The main board 30 includes integrated circuits and is connected to the power supply board 20 and the imaging unit 40. The main board 30 controls the operation of the power supply board 20 and the imaging unit 40 and performs correction processing of data handled by the imaging unit 40. A hub 31 is connected to the main board 30 and is used for connecting to the power supply Es and the external computer 200. There are no particular restrictions on the integrated circuits provided on the main board 30, and an FPGA (Field-Programmable Gate Array), ASIC (Application Specific Integrated Circuit), CPU, etc. can be selected and used as appropriate.

[0012] 3 is an exploded view of camera 1. Housing 10 has main body 11 with an internal space and lid 12. Power supply board 20, main board 30, and imaging unit 40 are arranged inside main body 11, and lid 12 is screwed to main body 11 to seal the interior of housing 10. Rubber gasket 13 is arranged between main body 11 and lid 12, ensuring waterproofing inside housing 10 when lid 12 and hub 31 are attached. A light-shielding cover 4 is attached to the first opening 2 and the second opening 3, and is configured to prevent natural light and the like that is not used to acquire a distance image (described later) from entering the housing 10.

[0013] 4 shows an exploded view of the imaging unit 40. The imaging unit 40 includes a light source substrate 41 on which a light source is attached, and an optical unit 50 including a lens and an imaging element. The imaging unit 40 of this embodiment uses two vertical cavity surface emitting lasers (VCSELs) as light sources, and two VCSELs 42 are attached to the light source substrate 41. The VCSELs 42 are just an example, and it is of course possible to use other light sources. The optical unit 50 includes a lens barrel 51 to which a lens 52 is attached, a lens holder 53 to which the lens barrel 51 is fixed, and an element substrate 55 to which an imaging element 56 is mounted. The imaging element 56 may be, for example, a CMOS image sensor, and is attached to the surface of the element substrate 55 facing the first opening 2. The imaging element 56 is further covered by a sensor cover 61 to which a bandpass filter is attached, and is configured so that light that passes through the lens 52 and enters the imaging element 56 passes through the bandpass filter before reaching the imaging element 56. In the camera 1, the lens holder 53 is fixed to the sensor cover 61, so that the lens 52 is aligned with respect to the imaging element 56.

[0014] A metal support block 60 is disposed around the lens 52 and lens holder 53 between the light source substrate 41 and the element substrate 55. The support block 60 is in contact with the light source substrate 41 and the element substrate 55, and is configured so that heat generated by the VCSEL 42 and the image sensor 56 when they are driven is dissipated to the outside of the housing 10 via the support block 60.

[0015] The camera 1 acquires a distance image based on the reflected light from the target object, which is the reference light emitted from the VCSEL 42, which is the light source, using the image sensor 56, and measures the distance to the object using the time-of-flight (TOF) method.

[0016] The VCSEL 42 or the like used as a light source of reference light in a range imaging device becomes much hotter during operation than a light source used in a flash, etc. Furthermore, the driver IC for controlling the VCSEL 42 also generates heat when driven, and if this heat is not properly released to the outside of the camera 1, the temperature inside the housing 10 can easily exceed 100°C, increasing the possibility of adversely affecting the operation of the camera 1. To prevent this, the camera 1 employs a heat dissipation mechanism that uses a metal support block 60. This will be explained in detail below.

[0017] FIG. 5 is a view of the light source substrate 41 as seen from the rear side. On the rear surface, two first heat dissipation pads 46 for dissipating heat from the VCSELs 42 are formed in positions directly behind the VCSELs 42, one for each VCSEL 42. The VCSELs 42 and the corresponding first heat dissipation pads 46 are thermally connected by a plurality of thermal wirings 47 (see FIG. 6) that penetrate the light source substrate 41 from front to back. In this embodiment, the thermal wirings 47 are through-holes, but a conductive layer may be formed on the inner surface or the pads may be filled with a conductor. The first heat dissipation pads 46 may be, for example, a square with sides of 3 mm. Two second heat dissipation pads 48 for dissipating heat from the driver ICs 43 are formed on the upper side of the first heat dissipation pad 46, one for each driver IC 43. The driver ICs 43 and the corresponding second heat dissipation pads 48 are thermally connected by thermal wiring (not shown) that penetrates the light source substrate 41. In this embodiment, the first heat dissipation pad 46, the second heat dissipation pad 48 and the wiring are all made of copper, but may be made of other materials with excellent thermal conductivity, such as aluminum. 4, driver ICs 43 corresponding to the two VCSELs 42 are attached to the front surface of the light source substrate 41. The driver ICs 43 may be arranged on the rear surface of the light source substrate 41.

[0018] The support block 60 according to this embodiment is made of die-cast aluminum, taking thermal conductivity into consideration. As shown in Fig. 4, the support block 60 has a space in the center in the left-right direction for arranging the optical unit 50, and has heat dissipation sections 71 fixed to the housing 10 on both left and right sides of this space. Each heat dissipation section 71 is located behind the first heat dissipation pad 46 and the second heat dissipation pad 48, and has a vertical hole 72 formed therein for fixing the support block 60 to the main body 11 of the housing 10.

[0019] FIG. 6 shows a cross-sectional view of the imaging unit 40 passing through the vertical hole 72. The vertical hole 72 has a first region 72a on the lower side and a second region 72b on the upper side, with a partition 73 having a through-hole provided between the first region 72a and the second region 72b. The columnar portion 11a of the main body 11 extends into the first region 72a. The support block 60 and the main body 11 are fixed to each other by a screw 76 disposed in the second region 72b that extends beyond the partition 73 and engages with the columnar portion 11a. At the same time, the inner circumferential surface of the first region 72a and the outer circumferential surface of the columnar portion 11a come into contact with each other, thereby thermally connecting the two at locations other than the lower surface of the support block 60.

[0020] The first heat dissipation pad 46 and the second heat dissipation pad 48 are thermally connected to the front surface of the heat dissipation section 71 with a heat dissipation sheet 75 sandwiched therebetween. There are no restrictions on the material of the heat dissipation sheet 75, and any known material can be appropriately selected and used, with suitable examples including silicone, acrylic resin, graphite, etc.

[0021] The back surface of the heat dissipation unit 71 is in contact with the element substrate 55 located around the imaging element 56. An L-shaped heat dissipation plate 81 is thermally connected to the back surface of the element substrate 55 on the side opposite to the heat dissipation unit 71. The portion of the element substrate 55 to which the heat dissipation plate 81 is connected is located directly behind the imaging element 56, and in a front view of the element substrate 55 seen from the first opening 2 side, at least a portion of the imaging element 56 and the heat dissipation plate 81 overlap. One end of the heat dissipation plate 81 is fixed to the main body 11 of the housing 10 by screws. The material of the heat sink 81 is preferably a metal with good thermal conductivity, such as aluminum, etc. In this embodiment, the housing 10 including the main body 11 is also made of aluminum.

[0022] FIG. 7 shows a cross-sectional view of the imaging unit 40 passing through the imaging element 56. A heat dissipation pad 57 is provided on the back surface of the element substrate 55 at a location directly behind the imaging element 56. The imaging element 56 and the heat dissipation pad 57 are thermally connected by columnar thermal wiring 58 made of a conductor arranged to fill a through-hole in the element substrate 55. Because there is more space on the back surface of the element substrate 55 than on the back surface of the light source substrate 41, the radial dimension of the thermal wiring 58 is larger than the thermal wiring 47 arranged on the light source substrate 41. A heat dissipation sheet 82 is arranged between the heat dissipation pad 57 and the heat dissipation plate 81, and the heat dissipation pad 57 and the heat dissipation plate 81 are thermally connected via the heat dissipation sheet 82. The heat dissipation pad 57 and the heat dissipation sheet 82 may be the same as or different from those provided on the light source substrate 41.

[0023] In the camera 1 according to this embodiment configured as described above, heat generated in each section during operation is smoothly transferred to the housing 10 and dissipated from the outer surface of the housing 10. Specifically, heat generated by the VCSEL 42 is transferred to the heat dissipation portion 71 of the support block 60 through the thermal wiring 47, the first heat dissipation pad 46, and the heat dissipation sheet 75, and then transferred from the bottom surface of the support block and the inner surface of the vertical hole 62 to the main body 11. Heat generated by the driver IC is transferred to the heat dissipation portion 71 of the support block 60 through the wiring on the light source board 41, the second heat dissipation pad 48, and the heat dissipation sheet 75. Heat generated by the imaging element 56 is transferred to the main body 11 through the thermal wiring 58, the heat dissipation pad 57, the heat dissipation sheet 82, and the heat dissipation plate 81. In addition, some of the heat is also transferred to the support block 60 through the element substrate 55.

[0024] In this way, in the camera 1, a heat dissipation path with good thermal conductivity that reaches the main body 11 of the housing 10 is formed for all of the VCSEL 42, the driver IC 43, and the image sensor 56, so that the generated heat can be efficiently dissipated to the outside and excessive temperature rise inside can be suitably suppressed. Furthermore, the heat dissipation path on the light source substrate 41 side, which includes the VCSEL 42 and driver IC 43 that generate a large amount of heat, passes through the support block 60, which has excellent thermal conductivity and a large volume. Therefore, the support block 60 functions as a buffer that temporarily stores heat when the heat dissipation from the main body 11 is not enough. As a result, the external dimensions of the housing 10 are reduced to a volume of 300 cm. 3 Even if the device is made small, such as below, it can dissipate heat smoothly and sufficiently prevent malfunctions caused by high temperatures.

[0025] As described above, in the camera 1 according to this embodiment, the light source substrate 41 is in contact with the metal support block 60 that is thermally connected to the housing 10, thereby achieving efficient heat dissipation while ensuring watertightness inside the housing 10. As a result, it becomes easier to increase the output of the light source, which also contributes to extending the measurable distance.

[0026] Although one embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and configuration changes and combinations within the scope that do not deviate from the gist of the present invention are also included.

[0027] For example, as in the modified element substrate 55A shown in Fig. 8, an element heat dissipation pad 59 may be provided on the surface on which the imaging element 56 is arranged. By thermally connecting the imaging element to the element heat dissipation pad 59 with wiring or the like (not shown) and bringing the element heat dissipation pad 59 into contact with the support block 60, heat can be dissipated more efficiently from the front side of the element substrate 55A. Furthermore, a heat dissipation sheet may be disposed between the element heat dissipation pad 59 and the support block 60.

[0028] Furthermore, the shape of the vertical hole of the support block and the columnar portion of the housing is not limited to the cylindrical shape shown in the embodiment, but can also be a rectangular column. By using a rectangular column shape, the contact area between the support block and the housing in the vertical hole can be further increased, making it easier to improve heat dissipation efficiency. However, increasing the contact area requires higher processing precision and can make the assembly process more complicated. Therefore, it is also effective to make the columnar portion slightly smaller and wrap a heat dissipation sheet around it that is easy to deform.

[0029] Furthermore, a portion of the heat dissipation unit can be extended upward so that it also comes into contact with the lid of the housing when the lid is closed. In this case, if the portions of the housing body and lid where the upper and lower surfaces of the heat dissipation unit come into contact are recessed with bottoms, the support block and the housing can also come into contact around the upper and lower surfaces, further increasing the contact area between them. [Explanation of symbols]

[0030] 1. Camera (distance imaging device) 10. Cabinet 30 Main board 40 Imaging unit 41 Light source board 42 VCSEL (laser light source) 43 Driver IC 46 First heat dissipation pad (pad) 48 Second heat dissipation pad (second pad) 50 Optical Unit 55 Element substrate 56 image sensor 59 Element heat dissipation pad (pad) 60 Support Block

Claims

1. an imaging unit having a light source, an optical unit, and an imaging element; a main board that controls the imaging unit; a metal housing that houses the imaging unit and the main board; Equipped with The imaging unit a light source substrate on which the light source is mounted; an element substrate on which the imaging element is mounted; a metal support block that is thermally connected to the housing and supports the optical unit from below, the light source substrate and the element substrate are thermally connected to the support block; the element substrate has columnar thermal wiring exposed on a surface opposite to the side on which the imaging element is arranged, and the imaging element and the housing are thermally connected via the thermal wiring; Range imaging device.

2. A heat sink arranged in contact with the housing; a heat dissipation pad covering the exposed surface of the thermal wiring; a heat dissipation sheet that thermally connects the heat dissipation pad and the heat dissipation plate; Further provided with 2. The distance imaging device according to claim 1.

3. the light source substrate has a conductive pad thermally connected to the light source on a surface opposite to the side on which the light source is arranged, and the light source substrate and the support block are thermally connected at the portion where the pad is arranged.

2. The distance imaging device according to claim 1.

4. the light source substrate has a driver IC that drives the light source and a second pad made of a conductor that is thermally connected to the driver IC, and the light source substrate and the support block are thermally connected at a location where the pad and the second pad are arranged.

4. The distance imaging device according to claim 3.

5. The light source is a laser light source.

2. The distance imaging device according to claim 1.

6. the element substrate has a conductive pad on a surface on which the imaging element is arranged, the conductive pad being thermally connected to the imaging element, and the element substrate and the support block are thermally connected at the portion where the pad is arranged; 2. The distance imaging device according to claim 1.

Images