KR101173676B1 - Rain sensor using Speckle pattern and method thereof - Google Patents

Abstract

According to an aspect of the present invention, a method of detecting raindrops in a rain sensor using a speckle pattern and a rain sensor using a speckle pattern includes: an optical signal generator for outputting light using a laser diode; A transmission part for guiding the light into the windshield glass to form a sparkle pattern; And an optical signal receiver configured to receive the light on the basis of the optical receiver and form a speckle pattern and output the characteristic value of the pattern. The waveguide pattern is formed in the receiving element by waveguide into the windshield glass and then integrated into the receiving element. If raindrops are present, the waveguide pattern is changed. The point that changes accordingly enables effective wiper control.

Description

Rain sensor using Speckle pattern and method according to the rain sensor using the speckle pattern and the rain sensor using the speckle pattern

The present invention relates to a rain sensor, and more specifically, to generate a control signal to drive the wiper of the vehicle by detecting the amount of moisture, such as raindrops or fog falling on the windshield glass, rain sensor The present invention relates to a rain sensor detecting a rain sensor using a rain sensor and a rain sensor that induces the formation of a speckle pattern in the receiving element and detects the amount of change.

If moisture accumulates on a transparent material such as glass or Plexiglass, it can interfere with human vision through the material. The vehicle is equipped with a motor-driven windshield wiper for wiping moisture away from the exterior surface of the windshield, generally over a wider area, at least within the driver's field of view to improve visibility through the windshield. come.

In most vehicles today, the windshield wiper system is not infinitely diverse, but includes a multi-position or variable speed switch that allows the driver to vary the range of speeds depending on the situation.

Wiper control is operated manually, typically including a delay characteristic, whereby the wiper is operated intermittently at a selected time delay interval.

Recently, a wiper control system has been developed that includes a moisture sensor or a rain sensor installed in one of the vehicle windows to automatically operate the wiper motor when moisture is present on the window surface.

Wiper control systems, including moisture sensors or rain sensors, are typically typically mounted on the windshield, but the system may be mounted on the rear window or other glass surface intended to remove moisture.

This wiper control system eliminates the inconvenience of the driver frequently adjusting the wiper speed as driving conditions change.

Wiper control systems use a number of different technologies to detect the moisture conditions encountered by automobiles, including conducting, capacitive, piezoelectric and light sensors.

The optical sensor operates on the principle that the light beam is deflected and diffuses in its normal path when moisture is present on the outer surface of the windshield.

Several methods have been proposed for the rain sensor, but other electronic methods except for the optoelectronic method are simple, but they are not universally reliable because they can't achieve the electrical output proportionally to large or small water particles. It is used.

The problem to be solved by the present invention by dividing the transmission light emitted from the laser diode in the front window of the car into two to form a sparkle pattern on the light receiving element, if raindrops are present, a change in the waveguide path occurs and as a result receive Since the speckle pattern on the surface of the device changes, the present invention relates to a rain sensor and a raindrop detection method using the rain sensor, which detects this and bases the wiper driving signal.

Rain sensor using a speckle pattern according to the present invention includes an optical signal generator for outputting light using a laser diode; A transmission part for guiding the light into the windshield glass to form a sparkle pattern; And an optical signal receiving unit for receiving the light based on the optical receiving element, forming a speckle pattern, and outputting a feature value of the pattern.

Preferably, the laser diode is characterized in that the multi-mode laser diode.

Preferably, the transfer unit includes a convex lens that focuses the light output by the optical signal generator and outputs the parallel light; A beam splitter configured to split the parallel light into two lights and output the split light; A first prism for injecting the two separated lights toward a windshield glass surface to which the rain sensor is attached; And a second prism which receives the two incident light beams and collects the two light beams into the light receiving device.

Preferably, the feature value is characterized in that the average value of the speckle pattern.

Method for detecting raindrops in the rain sensor using a sparkle pattern according to the present invention comprises the steps of generating light and then guided to the windshield glass surface to form a sparkle pattern; And after receiving the light by using the light receiving element, forming a speckle pattern and outputting a feature value of the pattern.

Preferably, the transmitting of the light may include converting the generated light into parallel light; Separating the parallel light into two lights; Injecting the two separated lights in a direction of a windshield glass surface to which the rain sensor is attached; And receiving the two incident light and collecting the incident light into the light receiving device.

Preferably, the light is generated using a multimode laser.

Preferably, the step of generating a signal for adjusting the operating speed of the wiper in proportion to the speckle feature value; characterized in that it further comprises.

According to the method for detecting raindrops in a rain sensor using a sparkle pattern and a rain sensor using a sparkle pattern according to the present invention, the transmission light emitted from the light source is divided into two paths and guided into the windshield glass. To form a speckle pattern on the receiving element, and if raindrops are present, a change is made in the waveguide path, so that the wiper can be effectively used by taking advantage of the fact that the speckle pattern on the surface of the light receiving element changes accordingly. You can control it.

1 is a view showing a basic configuration for generating a sparkle pattern according to the present invention.
2 is a block diagram showing the configuration of a rain sensor using a sparkle pattern according to the present invention.
Figure 3 is a plan view of a preferred embodiment of a rain sensor using a sparkle pattern according to the present invention.
Figure 4 is a cross-sectional conceptual view of a preferred embodiment of the rain sensor using a sparkle pattern according to the present invention.
5 is a flowchart illustrating a process of detecting raindrops in a rain sensor using a speckle pattern according to the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The principle of the speckle pattern and application examples to the present invention will be described, and the configuration of the present application and more specific embodiments will be described. First, the spackle pattern will be described.

Please refer to Fig. When light emitted from a multi-mode laser diode (110) is divided into two paths using an optical device such as a beam splitter (120), the light is collected on one light receiving element 140 plane again. Because of the coherent characteristics of laser light with a certain phase characteristic, a unique pattern is created. This pattern is called a speckle pattern. In this case, a beam splitter is used to make two paths, and one path is transmitted through the reflector 130.

Since one laser beam is a set of light beams having several propagation paths, each light beam has a different length of propagation path when it arrives on the surface of the light receiving element 140. Interference occurs on the plane. Due to such interference, a unique pattern appears on the light-receiving element plane and a photoelectric conversion current corresponding to the average value of the pattern is derived.

If an external factor that changes the intensity of light propagating on either of the two paths mentioned above occurs, a change also occurs in the spackle pattern, which is a unique pattern appearing on the light-receiving element plane, which also changes the average value of the pattern. Even changes occur.

The change of the photoelectric conversion current generated in this way is generated as a wiper drive signal.

Now, with reference to FIGS. 2 and 5, the configuration of the rain sensor and the raindrop detection method using the speckle pattern according to the present invention will be described. For simplicity of explanation and clarity of understanding, methods and apparatus are described together. In the following description of the configuration and the preferred embodiment of the present invention, those skilled in the art to which the present invention belongs to those who can understand the description will be omitted.

First, the optical signal generator 210 outputs light using a laser diode. At this time, the laser diode is preferably a multi-mode laser diode (step S510).

The transmitter 220 transmits the light output from the optical signal generator 210 to the optical signal receiver 230 to guide the light into the windshield glass to form a sparkle pattern. The transmission unit 220 preferably includes a convex lens 221, a beam splitter 223, a first prism 225, and a second prism 227. The convex lens 221 condenses the light output from the optical signal generator 210 to produce parallel light (step S520), and the beam splitter 223 separates the parallel light into two lights (S530). step). The first prism 225 enters the two received lights in the direction of the windshield glass surface to which the rain sensor is attached (S540). The second prism focuses and transmits the guided light to the optical signal receiver 230.

After receiving the light, the optical signal receiver 230 forms a speckle pattern (step S550), outputs a feature value of the pattern, and may apply a light receiving device that is generally used in a rain sensor. In addition, it is preferable to make the characteristic value of a speckle pattern into an average value here (S560 system). When the feature value is generated, the feature value changes according to the degree of raindrops, and as a result, the feature value can be used as a wiper control signal (step S570).

3 is a view for explaining a planar concept to better explain the configuration of FIG. 1 in a preferred embodiment of a rain sensor using a sparkle pattern according to the present invention, Figure 4 is to be applied to the windshield glass This is a diagram showing the appearance of the time in a cross-sectional view. This will be described with reference to FIGS. 3 and 4 simultaneously. Although shown in FIG. 3 but not shown in FIG. 4, the configuration may not be included when the rain sensor according to the present invention is viewed as one module. In other words, it is implemented outside the rain sensor according to the present invention means that only signals can be transmitted and received.

The transmitter 310 generates a signal for driving the laser diode. The laser diodes 315 and 420 generate light, and the convex lenses 320 and 430 focus light emitted from the laser diode to produce parallel light. The beam splitters 325 and 440, which are optical systems, separate the parallel light into two beams. Conceptually, one beam exiting the beam splitter 325 passes through the reflector 330 and a prism 335 that is optically connected to the reflector, and the other beam passes through the prism 340 to the receiving prism 345. Pass through) and collects in the light receiving element 350. In this way, the two beams are transferred to the windshield glass 410 in FIG. 4. That is, two beams passing through the beam splitter 440 are guided through the prism 450 and inside the windshield glass 410. Although shown as one dotted line in the figure, the beam splitter is actually two beams.

The beam guided through the windshield glass is collected by the light receiving element 470 via the prism 460. The beams thus collected form a speckle pattern on the light-receiving element 470 plane and output a photoelectric conversion current corresponding to the average value of the pattern. The receiver 360 receives the photoelectric conversion current, and the signal processor 370 takes appropriate measures such as amplifying the photoelectric conversion current or removing noise, and then supplies a signal for wiper driving through the wiper drive interface 480. Output This signal is sent to the CPU to use as basic information to drive the wiper.

To sum up again, when raindrops fall on either glass surface of the two paths guided inside the windshield glass, external leakage of the guided light occurs, which causes a change in the spackle pattern formed on the light receiving element plane. A change also occurs in the photoelectric conversion current. The rain sensor according to the present invention is configured by using the change of the speckle pattern, and the raindrop is detected.

Although the present invention has been described with reference to one embodiment shown in the accompanying drawings, it is merely an example, and those skilled in the art may realize various modifications and equivalent other embodiments therefrom. I can understand. Accordingly, the true scope of protection of the present invention should be determined only by the appended claims.

The method of the present invention can also be embodied as computer readable code on a computer readable recording medium. A computer-readable recording medium includes all kinds of recording apparatuses in which data that can be read by a computer system is stored. Examples of the computer-readable recording medium include a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like, and may be implemented in the form of a carrier wave (for example, transmission via the Internet) . The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

Claims (8)

An optical signal generator for outputting light using a laser diode;
A transmission part for guiding the light into the windshield glass to form a sparkle pattern; And
And an optical signal receiver configured to form a speckle pattern and output a feature value of the pattern after receiving the light based on the optical receiver.
A convex lens for condensing the light output by the optical signal generator and outputting the light as parallel light;
A beam splitter configured to split the parallel light into two lights and output the split light;
A first prism which injects the two separated lights toward a windshield glass surface to which a rain sensor is attached; And
And a second prism for receiving the two incident light beams and collecting the two light beams into the light receiving device. The method of claim 1, wherein the laser diode
Rain sensor using a speckle pattern, characterized in that the multi-mode laser diode. The method of claim 1, wherein the feature value of the speckle pattern
Rain sensor using a speckle pattern, characterized in that the average value of the speckle pattern. The method of claim 1, wherein the rain sensor
And a signal processor for generating a signal for adjusting an operation speed of the wiper in proportion to the feature value of the speckle pattern. Generating light and transmitting the light to a windshield glass surface to form a speckle pattern; And
Receiving the light by using a light receiving element, forming a speckle pattern and outputting the feature value of the pattern; including, but the step of transmitting the light,
Focusing the generated light and converting the generated light into parallel light;
Separating the parallel light into two lights;
Injecting the two lights into the windshield glass surface to which the rain sensor is attached; And
And receiving the two incident light and collecting the incident light into the optical receiving element. The raindrop detection method of the rain sensor using a speckle pattern. The method of claim 5, wherein the light is
A method for detecting raindrops in a rain sensor using a speckle pattern, characterized in that it is generated using a multi-mode laser. The method of claim 5, wherein the feature value of the speckle pattern
Raindrops are detected by the rain sensor using a speckle pattern, characterized in that the average value of the speckle pattern. The method of claim 5,
Generating a signal for adjusting the operating speed of the wiper in proportion to the feature value of the speckle pattern; Method for detecting raindrops in the rain sensor using a speckle pattern.

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