JPH0526551Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention relates to a rain/snow sensor/polarized light receiving device that detects, discriminates, and measures rainfall and snowfall at a desired spatial location using scattering in the plane of polarization. .

[Prior Art] Conventionally, when detecting rain or snow by reflection of light, it is determined whether the reflective object is a raindrop or a snowflake based on the scattering of the plane of polarization upon reflection. That is,
It emits a polarized light beam (temporarily vertically polarized light) and determines the attributes of the reflecting object by detecting how much horizontally polarized light components are included in the reflected waves.

Figure 2 is a diagram showing the configuration of a conventional device, in which 1 is reflected light, 2 is a light receiving lens system, 3 is parallel light, 4 is a polarization separation beam splitter, 5 and 9 are condensing lenses, and 6a , 6b are optical filters, and when the reflected light 1 is infrared rays, the optical filters 6a and 6b are, for example, visible light cut filters. 7 is a vertical light receiving element, 8 is a vertical receiver, 1
0 is a horizontal light receiving element, 11 is a horizontal receiver, and 12 is a signal processing section.

A vertically polarized light beam emitted from a projector (not shown) is reflected by a reflective object (not shown) and returns as reflected light 1. The light-receiving lens system 2 collects the reflected light 1 and makes the reflected beam enter the polarization-separating beam splitter 4 as parallel light 3 that is spread almost completely onto the light-receiving surface of the polarization-separating beam splitter 4. A vertically polarized component of the parallel light 3 passes through a condenser lens 5 and an optical filter 6a, is converted into an electrical signal by a vertical light receiving element 7, and enters a vertical receiver 8.

On the other hand, the horizontally polarized component passes through the condensing lens 9 and the optical filter 6b, is converted into an electrical signal by the horizontal light receiving element 10, and enters the horizontal receiver 11.

The ratio of the output of the vertical receiver 8 and the output of the horizontal receiver 11 is determined by the signal processing unit 12 as the ratio of the vertical polarization component and the horizontal polarization component included in the reflected light 1.
Processed in

[Problems to be solved by the invention] Since the conventional rain/snow sensor polarization receiver as described above is configured as described above, the optical system after the polarization separation beam splitter 4 becomes complicated.
Focus error of condensing lenses 5 and 9, optical filter 6
The variation in the characteristics of the light receiving elements 7, 10
There is a problem in that this affects the output of the signal processing unit 12 and causes an error in calculation of the ratio of the vertically polarized light component to the horizontally polarized light component in the signal processing section 12.

This invention was made in order to solve this problem, and the purpose is to obtain a polarized light receiving device for a rainfall/snowfall sensor in which the structure of the optical system is simplified and parts where errors occur are eliminated.

[Means for Solving the Problems] The rain/snow sensor polarization receiver according to this invention omits all optical systems after the polarization separation beam splitter, and each light receiving element is attached to the polarization output surface of the polarization separation beam splitter. Each was directly fixed, and a receiving lens (optical lens) was provided so that the reflected light was focused on the light-receiving surface of the light-receiving element, and an optical filter was placed in front of the polarization separation beam splitter.

[Function] In this invention, all optical systems after the polarization separation beam splitter are omitted, and the light receiving elements are directly fixed to the polarization output surface of the polarization separation beam splitter, so that the reflected light is not reflected onto the light receiving surface of the light receiving element. A receiving lens (optical lens) is provided to focus the beam, and an optical filter is placed in front of the polarization separation beam splitter, so the optical system after the polarization separation beam splitter can be omitted, simplifying the equipment. It becomes possible to remove parts where errors often occur.

[Example] Hereinafter, an example of this invention will be described using the drawings. FIG. 1 is a configuration diagram showing an embodiment of this invention. In the figure, the same reference numerals as in FIG. 2 indicate the same or corresponding parts, and 14 is a receiving lens (optical lens);
16 is an optical filter, and 18 is a first light receiving element, which is assumed to be a vertical light receiving element. 19 is the second
This is a light-receiving element, and this is temporarily assumed to be a horizontal light-receiving element.

The vertical light receiving element 18 is fixed at the center position of the output surface where the vertically polarized light beam of the polarization separation beam splitter 4 reaches, and the horizontal light receiving element 19 is fixed at the center position of the output surface where the vertically polarized light beam of the polarization separation beam splitter 4 reaches. Fix it at the center position of the output surface where it reaches.

When the single receiving lens 14 is adjusted so that the reflected light 1 is focused on the light receiving surface of the vertical light receiving element 18, the horizontally polarized light beam is focused on the light receiving surface of the horizontal light receiving element 19. Start tying.

The optical filter 16 is composed of, for example, a band pass filter or a visible light cut filter, but variations in its characteristics also occur in vertical polarization.
It also acts on horizontally polarized light, so it does not cause measurement errors.

[Effects of the device] As explained above, this device omits all optical systems after the polarization separation beam splitter, and each light receiving element is directly fixed to each polarization output surface of the polarization separation beam splitter. A single receiving lens was provided on the light receiving surface of the light receiving element so that each reflected light was focused, and an optical filter was placed in front of the polarization separation beam splitter, so that the optical filter after the polarization separation beam splitter was The system can be omitted, the apparatus can be simplified, parts where errors often occur can be removed, and precise measurements with fewer errors can be performed.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of this invention, and FIG. 2 is a block diagram showing a conventional device. 1...Reflected light, 4...Polarization separation beam splitter, 8...Vertical receiver, 11...Horizontal receiver, 1
2... Signal processing section, 14... Receiving lens, 16...
...Optical filter, 18...Vertical light receiving element, 19...
...Horizontal light receiving element. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims for Utility Model Registration] A rain/snow sensor polarization receiver that emits polarized light beams in a predetermined wavelength band onto a reflective object such as raindrops or snowflakes, and detects scattering of the polarization plane of the reflected light from the reflective object. , a polarization separation beam splitter that separates reflected lights having different incident polarization planes and outputs them in a first direction and a second direction; a first light-receiving element that is fixed; a second light-receiving element that is directly fixed to the exit surface of the polarization separation beam splitter in the second direction; The reflected light incident on the polarization separation beam splitter is transmitted to the first light receiving element and the second light receiving element.
A single optical lens that simultaneously focuses its light onto each light receiving surface of the light receiving element of A rainfall/snowfall sensor polarization receiving device comprising: