JPH0630734U - Optical sensor - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce the manufacturing cost of an optical sensor using PBS. [Structure] Plate type PBS1 instead of cube type PBS
8 is used. The plate-shaped PBS 18 is arranged in front of the lens 10 of the light projecting section. The plate-shaped PBS 18 is supported by the slits 16 formed on the inner surfaces of the support walls 12 and 14. The slit 16 is formed so as to form an angle of 45 ° with respect to the light projecting direction.
Becomes a predetermined posture with respect to the lens 10 of the light projecting unit.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an optical sensor used in a backscattered light receiving type polarization plane radar.

[0002]

[Prior art]

 For example, an optical radar that identifies rain, snow, fog, etc. projects light of a predetermined polarization from a light projecting unit onto an object in front (raindrops, snowflakes, water drops of fog, etc.), and the backscattered light thereof. It is configured to receive by the light receiving unit, and the snow, fog, etc. are identified based on the reception result. As described above, in an optical measuring device that transmits and receives light of a predetermined polarization, a polarization beam splitter (hereinafter referred to as PBS) that aligns the polarization of the light that is projected or received is essential. Conventionally, a cube-shaped PBS having a cubic shape has been used as a PBS in this type of optical measuring device. The cube-shaped PBS is a PBS that can accurately separate a vertical polarization plane component and a horizontal polarization plane component from an unpolarized wave.

[0003]

[Problems to be solved by the device]

 However, although the cube-shaped PBS can separate the vertically polarized component and the horizontally polarized component with high accuracy, it has a problem that the cost is high. When manufacturing an optical sensor using such a cube-shaped PBS, it is difficult to reduce the product cost due to an increase in component cost.

The present invention has been made to solve the above problems, and it is possible to project and receive a light beam of a predetermined polarization without using an expensive optical component such as a cube PBS. The aim is to realize a possible optical sensor.

[0005]

[Means for Solving the Problems]

 In order to achieve such an object, in the optical sensor according to claim 1 of the present invention, the PBS used for separating the light beam of a predetermined polarization from the projected light beam is a plate type PBS having a flat plate shape. And a means for supporting the PBS by a slit formed so as to form a predetermined angle with respect to the projection direction.

Further, in the optical sensor according to claim 2 of the present invention, the PBS for separating the light beam of the predetermined polarization from the backscattered light and allowing the light receiving section to receive the light is a plate type PBS having a flat plate shape. It is characterized by comprising means for supporting the PBS by means of slits formed so as to form a predetermined angle with respect to the light receiving direction.

[0007]

[Action]

 In the first aspect of the present invention, the PBS is a plate type PBS, and the plate type PBS is supported by the slit. Since the plate-shaped PBS has a flat plate shape, in order to use it for light projection, it is necessary to support it at a predetermined angle with respect to the light projection direction. In the present invention, this support is performed by the slit formed to form a predetermined angle with respect to the light projecting direction. Therefore, according to the present invention, the plate-type PBS is used to favorably separate the predetermined polarization plane component from the light beam relating to the light projection. Further, since the plate type PBS is much cheaper than the cube type PBS, in the present claim, the optical sensor using the PBS can be manufactured much cheaper than the conventional one.

Further, also in the optical sensor according to the second aspect of the present invention, the same operation as in the first aspect can be obtained. In the present claim, the PBS provided on the light receiving portion side rather than the light projecting portion side is a plate type PBS, and this PBS is supported by the slit formed similarly to the first aspect.

[0009]

【Example】

 Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows the operation of the conventionally used cube PBS and the plate PBS according to the features of the present invention. First, as shown in FIG. 1 (a), the cube-shaped PBS separates an incident unpolarized wave into a vertical polarization plane component and a horizontal polarization plane component, and emits the vertical polarization plane component to the right in the figure. . Similarly, the plate type PBS shown in FIG. 1B also emits a vertical polarization plane component in the right direction in the figure, but at that time, an unnecessary polarization plane component from the plate PBS (horizontal polarization plane component in the figure). Component) is also emitted.

Therefore, in an optical sensor that projects and receives a light beam having a predetermined plane of polarization, it is preferable to use a cube PBS strictly from the viewpoint of separating polarization plane components, but to reduce the manufacturing cost thereof. However, it is preferable to use a plate-type PBS that can be manufactured at a cost of about one-third that of a cube-type PBS, although it has a problem of polarization plane component.

Further, since the unnecessary polarization plane component emitted from the plate-type PBS is about 10% with respect to the necessary polarization plane component, such polarization plane component has a large non-polarized wave with incident power. If it is, there is no particular problem. That is, when the incident light beam has a large power like the PBS used on the light projecting side, there is no problem, and the plate-type PBS is used in place of the cube-type PBS, which greatly reduces the cost. Can be said to be Furthermore, this merit becomes particularly remarkable when a large number of PBSs are used.

FIG. 2 shows the configuration of the optical sensor according to the first embodiment of the present invention, particularly the lens mount of the light projecting portion thereof. As shown in this figure, the projection lens mount according to the present embodiment is provided with support walls 12 and 14 on the front left and right sides of the lens 10, and inside the support walls 12 and 14 with respect to the projection direction. The slit 16 is formed to have an inclination of about 45 °, and the slit 16 supports the plate-shaped PBS 18. In this embodiment, since the plate-shaped PBS is supported by the slits 16 provided in this way, the posture of the PBS 18 as seen from the lens 10 and the light-emitting elements such as LEDs behind the lens 10 is The angle can be set to a predetermined angle (45 °) with respect to the projection direction. Therefore, when the plate-type PBS 18 is used instead of the cube-type PBS, the polarization plane separation performance can be preferably maintained.

Note that this embodiment is an example relating to a light projecting lens mount, but a plate type PBS may be used in the light receiving lens mount of the optical sensor and a supporting structure with the slit 16 may be used.

FIG. 3 shows the configuration of an optical sensor according to a second embodiment of the present invention. Shown in this figure is the structure of a front cover in which a plurality of (12 in this figure) light projecting lens mounts 20 according to the first embodiment shown in FIG. 2 are arranged in an annular shape. The light receiving window 22 is arranged at the center of the circle related to this arrangement, and the back scattered light by the object in front of the light beam emitted from the light projecting lens mount 20 is received by the light receiving portion 22. Each mount 20 is integrally formed.

Therefore, also in this embodiment, the same effect as that of the first embodiment can be obtained, and further, the effect of improving the light receiving efficiency due to the annular arrangement can be obtained. In this embodiment, a plate type PBS may be used on the light receiving window 22 side. In addition, in this embodiment, since the number of PBSs used is large, the cost reduction effect is very remarkable. In addition, even though a large number of PBSs are used, the postures of the PBSs can be matched with each other by integrally forming the front cover.

[0017]

[Effect of device]

 As described above, according to claim 1 of the present invention, the plate type PBS is used as the PBS on the light projecting side, and the plate type PBS is provided with the slit so as to have a predetermined posture in the light projecting direction. Since the plate-shaped PBS is supported by the above, it is possible to reduce the manufacturing cost while maintaining the performance related to the separation of the predetermined polarization component.

Further, according to the second aspect of the present invention, the plate type PBS is used as the PBS on the light receiving portion side, and the plate type PBS is supported by the slit so as to have a predetermined posture in the light receiving direction. The same effect as in claim 1 can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram for explaining the operation of a polarization beam splitter (PBS), and FIG.
(B) is a figure which shows the effect | action of plate type PBS.

2A and 2B are views showing a configuration of a light projecting lens mount according to a first embodiment of the present invention, FIG. 2A is a front perspective view, and FIG. 2B is an inner view of a support wall.

FIG. 3 is a front perspective view showing the structure of a front cover of an optical sensor according to a second embodiment of the present invention.

[Explanation of symbols]

 10 Lenses 12 and 14 Support Wall 16 Slit 18 Plate Polarization Beam Splitter (PBS) 20 Lens Mount for Projection 22 Light Receiving Window

Claims (2)

[Scope of utility model registration request] 1. A light projecting unit that emits a light beam, a polarization beam splitter that separates a light beam of a predetermined polarization from the light beam emitted from the light projecting unit, and projects the light beam toward an object in a predetermined direction, and backscattering by this object. In the optical sensor including a light-receiving unit that receives light, the polarization beam splitter is a plate-type polarization beam splitter having a flat plate shape, and the polarization beam splitter makes a predetermined angle with respect to the projection direction. An optical sensor comprising means for supporting by the formed slit. 2. A light projecting unit for emitting a light beam and projecting the light beam toward an object in a predetermined direction, a polarization beam splitter for separating a light beam of a predetermined polarization from backscattered light by the object, and a polarization beam splitter for separating the light beam. In the optical sensor including a light receiving unit that receives a light beam, the polarization beam splitter is a plate-type polarization beam splitter having a flat plate shape, and the polarization beam splitter makes a predetermined angle with respect to the light receiving direction. An optical sensor comprising means for supporting by the formed slit.