JP4239168B2 - Visual sensor - Google Patents

Description

  The present invention relates to a visual sensor that reflects a wide range of ambient light with a reflecting member and picks up an image by an imaging means such as a CCD (Charge Coupled Device).

Conventionally, various omnidirectional vision sensors have been proposed, and for example, disclosed in Patent Document 1 and Patent Document 2. Such an omnidirectional visual sensor 1 reflects ambient light with a hyperboloidal reflecting mirror 2 and images the surroundings with an imaging device 3 such as a CCD (see FIG. 5).
JP-A-10-160463 JP 2000-128031 A

  The image sensor 3 is mounted on the circuit board 4, and the circuit board 4 on which the image sensor 3 is mounted is disposed on the bottom wall portion 5 a of the case body 5. A cylindrical tube 6 made of a translucent material is provided on the side wall 5 b of the case body 5, and the reflection mirror 2 is disposed inside the tube 6. A lid body 7 is disposed in the upper opening 6 a of the cylindrical body 6, and the reflection mirror 2 is fixed to the lid body 7. The reflection mirror 2 has a hyperboloid shape, and is disposed so as to hang from the lid body 7 with the apex of the hyperboloid shape facing downward.

  The omnidirectional visual sensor 1 has a visual field range A1 up to an elevation angle of about 20 ° and a visual field range A2 up to a depression angle of about 50 °. Yes. The visual field range is a region that can be monitored by the image sensor 3.

  However, the omnidirectional visual sensor 1 has a problem that it cannot be provided at low cost because of the large number of parts. In particular, the cylindrical body 6 made of a translucent material has no optical effect, so if the cylindrical body 6 can be eliminated, the number of parts can be reduced. A first object of the present invention is to provide a visual sensor that has a small number of parts and can be manufactured at low cost.

  Furthermore, the omnidirectional visual sensor 1 is obstructed by the lid 7, so that the upward visual field range A1 is slightly narrower than the downward visual field range A2, and the side wall 5b of the case body 5 is obstructed. Thus, there is a problem that the blind spot range S is present below. The second object of the present invention is to provide a visual sensor having a degree of freedom in the designed visual field range.

According to a first aspect of the present invention, an optical member made of a solid translucent material having an incident surface on which ambient light is incident, and the optical member are provided integrally with the optical member and reflect the ambient light. A visual sensor comprising: a reflecting member; and an imaging unit that images the ambient light reflected by the reflecting member , wherein the optical member is reflected by the reflecting member and a base portion having a recess. And a light guide portion that guides the ambient light to the imaging means, and the reflective member is a reflective layer that is coated on the concave portion .

  According to a second aspect of the present invention, a low reflective layer is formed on at least the incident surface of the optical member.

According to a third aspect of the present invention, the reflecting layer has a hyperboloid shape.

According to a fourth aspect of the present invention, the incident surface is a spherical surface centered at the focal point of the hyperboloid shape.

According to the present invention, as described in claim 5 , the ambient light traveling toward the hyperboloid focal point is refracted by the incident surface and incident on the optical member.

  The number of parts can be reduced, and an inexpensive visual sensor can be provided.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. 1 and 2 show a first embodiment.
The visual sensor 10 includes an optical member 11, a case body 12, an imaging element 13 (imaging means), a circuit board 14, and a reflection layer 15 (reflection member).

The optical member 11 is made of a solid translucent resin (for example, polycarbonate), and has a substantially spherical base portion 16 and a substantially cylindrical light guide portion 17. The base portion 16 of the optical member 11 has a spherical incident surface 16a on which the ambient light L is incident, and a hyperboloid concave portion 16b. The incident surface 16a of the optical member 11 is a spherical surface centered on the hyperboloid focus f1. An incident surface 16a of the base 16, the outer peripheral surface 17a of the light guide portion 17, respectively the low reflective layer 19 is coated. In this specification, the “spherical surface” is at least a part of the surface of the sphere, not the entire surface of the sphere.

  A reflective layer 15 made of aluminum (Al) is formed in the recess 16 b of the optical member 11. The reflective layer 15 is formed by coating the recess 16b by a method such as vapor deposition. The light guide portion 17 of the optical member 11 guides the light reflected by the reflection layer 15 to the image sensor 13 and has an emission surface 17 b that faces the image sensor 13. The exit surface 17b of the light guide portion 17 is a spherical surface centered on the focal point f2. The focal point f2 is a focal point of a hyperboloid shape (the other of the two-leaf curved surface) that is paired with the hyperboloid shape (one of the two-lobe curved surface) of the recess 16b. The case body 12 includes a bottom wall portion 12a and a cylindrical side wall portion 12b, and the optical member 11 is fixed to the side wall portion 12b. The image sensor 13 is mounted on the circuit board 14 and is fixed to the bottom wall portion 12 b of the case body 12.

  The ambient light L is incident on the inside of the base portion 16 from the incident surface 16a, is reflected by the reflective layer 15, and is guided to the image sensor 13 by the light guide portion 17 (see FIG. 2). Since the ambient light L toward the hyperboloid-shaped focal point f1 is incident on the incident surface 16a perpendicularly, it is not refracted by the incident surface 16a. The ambient light L reflected downward by the reflective layer 15 passes through the focal point f2, exits from the exit surface 17b, and is imaged by the image sensor 13. The visual sensor 10 has a visual field C1 from 0 ° to an elevation angle of about 30 ° and a visual field C2 from 0 ° to a depression angle of 30 °. The image data output from the image sensor 13 is output to an image processing unit (not shown) and is used for recognition of obstacles around the visual sensor 10.

  3 and 4 show a second embodiment. In the second embodiment, only the optical member 21 is different, and the other configuration is the same as that of the first embodiment. Therefore, the same reference numerals are given and the description thereof is omitted.

  The optical member 21 is made of a solid translucent resin, and has a substantially hemispherical base portion 26 and a substantially cylindrical light guide portion 27. The base portion 26 of the optical member 21 has an incident surface 26a on which the ambient light L is incident, and a hyperboloid-shaped concave portion 26b. A reflective layer 25 (reflective member) is formed in the recess 26 b of the optical member 21. A low reflection layer 28 is coated on the incident surface 26 a of the base 26.

  The ambient light L is refracted by the incident surface 26a, enters the optical member 21, and is reflected by the reflection layer 25 (see FIG. 4). The ambient light L reflected downward by the reflective layer 25 is imaged by the image sensor 13. The visual sensor 20 has a field of view D up to a depression angle of 80 °. The shape of the incident surface 26a of the optical member 21 is such that each incident angle I at each incident position of the ambient light L that is incident from the field of view D, refracted by the incident surface 26a, reflected by the reflective layer 25, and directed toward the focal point f2. It is the shape which is equal and each refraction angle R becomes equal respectively.

According to the first embodiment and the second embodiment, the cylindrical body 6 and the lid body 7 which are conventionally necessary are not provided, and the number of parts is small, so that the assembly is simplified and the visual sensor 10 is manufactured at a low cost. be able to.
In addition, according to the present invention, the visual field range can be appropriately designed. In the first embodiment, since the conventional lid body 7 is not provided, the upward visual field range C1 is wider than the conventional visual field range A1, In the second embodiment, since the ambient light L incident from below is refracted by the incident surface 21a, the lower ambient light L can also be captured by the imaging device 13, and the downward visual field range D is larger than the conventional visual field range A2. Become wider.

  Further, by providing the low reflection layers 18, 19, 28 on the optical members 11, 21, when the ambient light L is incident on the optical members 11, 21, the ambient light L is not reflected, and the ambient light L Loss is reduced, and a clear image can be obtained. The reflective layer 15 is not limited to a hyperboloid shape, and may be, for example, a conical shape.

  Further, the image pickup means is the image pickup device 13 such as a CCD, but may be a CMOS camera, for example. Moreover, the low reflection layers 18, 19, and 28 are only required to be formed on at least the incident surfaces 16a and 26a, and may be provided on the emission surfaces 17b and 27b, for example.

Sectional drawing which shows 1st embodiment of this invention. Optical path explanatory drawing which shows 1st embodiment same as the above. Sectional drawing which shows 2nd embodiment of this invention. Optical path explanatory drawing which shows 2nd embodiment same as the above. Sectional drawing which shows a prior art example.

Explanation of symbols

11 Optical member 13 Image sensor 15 Reflective layer (reflective member)
16a Incident surface 16b Recess 21 Optical member 25 Reflective layer (reflective member)
26a Incident surface 26b Recess

Claims (5)

An optical member made of a solid translucent material having an incident surface on which ambient light is incident, a reflecting member that is provided integrally with the optical member and reflects the ambient light, and the surroundings reflected by the reflecting member A visual sensor comprising imaging means for imaging light ,
The optical member includes a base portion having a recess, and a light guide portion that guides the ambient light reflected by the reflecting member to the imaging unit.
The visual sensor, wherein the reflective member is a reflective layer coated on the concave portion.   The visual sensor according to claim 1, wherein a low reflection layer is formed on at least the incident surface of the optical member. The visual sensor according to claim 1 , wherein the reflective layer has a hyperboloid shape. The visual sensor according to claim 3 , wherein the incident surface is a spherical surface centering on the focal point of the hyperboloid shape. The visual sensor according to claim 3 , wherein the ambient light directed toward the focal point of the hyperboloid is refracted on the incident surface and is incident on the optical member.

Images