JPS5985944A - Liquid detector for automatic wind shield wiper controller device - Google Patents

Abstract

PURPOSE:To facilitate the fixing work to a wind shield and to ensure the fixed state all the time regardless of the change in thermal expansion of the wind shield, by forming a supporting member of a liquid detector with a material whose refractive index is the same as the refractive index of a front glass for light and coefficient of thermal expansion is the same as the cefficient of thermal expansion of the front glass. CONSTITUTION:In order to attach a liquid detector 20 to a front glass 10, a light emitting element 24 and a light receiving element 25 are assembled to both protruded parts 23a and 23b of a supporting member 23, a thin reflecting plate 22 is stuck to the lower surface of a supporting member 21, and the lower surface of the supporting member 23 is bonded to the upper surface of the supporting member 21. Then the supporting member 21 for the liquid detector 20 is bonded to a front glass inner surface 12 through the thin reflecting plate 22 at a lower surface 21a. Thereafter, the supporting member 23 is coated by a cover 16. At this time, even though the glass 10 is changed by the thermal expansion due to the ambient temperature, the supporting member 21 follows the change in thermal expansion of the glass 10 since the member has approximately the same coefficient of thermal expansion as that of the glass 10. Therefore, the lower surface 21a of the supporting member 21 is always closely bonded to the front glass inner surface 12.

Description

[Detailed Description of the Invention] The present invention relates to a windshield wiper automatic control device,
In particular, a windshield that uses photoelectric conversion to detect the adhesion of liquid such as raindrops on the outer surface of the windshield wiper of vehicles, aircraft, ships, etc., and generates this detection result as a detection signal necessary for automatic control of the windshield wiper. The present invention relates to a liquid detector for an automatic wiper control device.

Conventionally, this type of liquid detector is provided, for example, on a part of the inner surface of the windshield corresponding to the sliding area on the outer surface of the windshield of the wiper blade constituting the windshield wiper, and includes a light emitting element and a light receiving element. When there is no liquid such as raindrops adhering to the outer surface of the windshield, the light generated from the light receiving element is made to enter the windshield so as to be totally reflected within the windshield, and the adhering liquid is is present, the amount of light reflected within the windshield is reduced, and the light emitted from the windshield after reflection within it is received by the light receiving element, and the result of this light reception is transmitted to the windshield wiper. Some devices are designed to generate detection signals necessary for automatic control.

However, in such a liquid detector, the light emitting element is formed of a material having a refractive index substantially the same as the refractive index of the windshield for light so that the light can be incident on the windshield. A support member similar to the support member is fixed to a part of the inner surface of the windshield through a support member, and another support member similar to the support member is provided so that the light receiving element can receive light emitted from the windshield. The supporting members must be fixed to a part of the inner surface of the windshield through the support members, and prior to these fixing operations, the optical axis alignment between the light emitting axis of the light emitting element and the light receiving axis of the light receiving element is performed using the support members. This has to be done properly in relation to the optical function of the windshield, and there is a problem in that the above-mentioned work requires unnecessary effort and time. Further, when each of the supporting members has a coefficient of thermal expansion different from that of the windshield, the difference in thermal expansion between each of these supporting members and the windshield causes each of the supporting members to move away from the windshield at the joint surface thereof. There is a problem in that the peeling makes it impossible for light from the light emitting element to enter the windshield and for the light receiving element to receive light emitted from the windshield.

The present invention has been made with this in mind, and its purpose is to facilitate the fixing work to the windshield and to ensure that the state of fixation to the windshield is independent of changes in thermal expansion of the windshield. An object of the present invention is to provide a liquid detector for an automatic windshield wiper control device that is always maintained without fail.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. The drawings show a state in which a liquid detector 20 according to the present invention is assembled to a windshield 10 of a vehicle. Liquid detector 2
-0 has a support member 21, and this support member 21
is formed of a glass material having a refractive index substantially the same as the refractive index for light of the windshield 10 and a coefficient of thermal expansion substantially the same as the coefficient of thermal expansion of the windshield 10, and at its lower surface ILa. , an appropriate transparent adhesive (windshield adhesive) is applied to a portion of the inner surface 12 of the windshield 10 corresponding to the sliding area on the outer surface 11 of the windshield 10 of the wiper blade constituting the windshield wiper of the vehicle through the reflective thin plate 22. 10, respectively). The reflective thin plate 22 is made of a reflective material having almost the same coefficient of thermal expansion as the windshield 10, and is attached to the center of the lower surface 21H of the support member 21 by a stamping method so as to be in close contact with the inner surface 12 of the windshield. , totally reflects the incident light on its lower surface.

The liquid detector 20 also includes a support member 23 that is assembled to the support member 21 and integrally supports the light emitting element 24 and the light receiving element 25. The support member 23 is not understood from the illustrated cross section. As shown, the pair of left and right raised portions 23a, 2
3b are arranged symmetrically on both sides of the thin part 23C,
It is formed from a synthetic resin material by an integral molding method, and its lower surface is attached to the upper surface of the support member 21 by adhesive. In this case, where the thin wall portion 23C of the support member 23 is joined to the upper surface of the support member 21 at its lower surface, the recesses 23d and 23e formed on the lower surface of the rain shower portions 23a and 23b during molding are formed. , are connected to the respective protrusions 21b' and 21c formed on the upper surface of the support member 21 correspondingly, so that the support member 2 of the support member 23
The assembly position relative to 1 is uniquely and easily determined.

A stepped through hole 23 is provided in the left raised portion 23a of the support member 23.
f is formed in the inclined shape shown in the figure when molding the support member 23, and the light emitting element 24 is fitted and inserted into this stepped through hole 23f, and the stepped through hole 23f is formed with epoxy resin at the base thereof.
It is fixed to the stepped part. In such a case, the stepped through hole 23
The central axis of f, that is, the light emitting axis of the light emitting element 24 is
1 and the windshield outer surface 11 of the light emitting axis of the light emitting element 24.
The angle between the light emitting axis and the normal to the windshield outer surface 11 determined at the intersection 11a with the windshield 1 is
Critical angle and windshield 10 in relation to air at 0
The value is between the critical angle in relation to liquids such as rain. This means that when no liquid is attached to the outer surface 11 of the windshield, the light emitted from the light emitting element 24 along its light emitting axis passes straight through the left protrusion 21b of the support member 21 into the windshield 10, and the light that is emitted from the light emitting element 24 passes straight into the windshield 10 and passes through the outer surface of the windshield. 11 and enters the reflective thin plate 22, and the windshield outer surface 1
This means that when a liquid adheres to a portion including the intersection 11a of 1, the amount of light reflected at the intersection 11a decreases. Note that the light emitting element 24 has a built-in near-infrared light emitting diode, and when this light emitting diode is turned on, it emits light in the form of a beam along its light emitting axis.

On the other hand, in the right raised portion 23b of the support member 23, a stepped through hole 23g is formed in an inclined shape as shown in the figure at a position symmetrical to the stepped through hole 23f with respect to the point of incidence of light on the reflective thin plate 22. This stepped through hole 23 is formed when the support member 23 is molded.
The light receiving element 25 is fitted and inserted into the hole g, and its base is fixed to the stepped portion of the stepped through hole 23g using epoxy resin. In such a case, the central axis of the stepped through hole 23g, that is, the light receiving axis of the light receiving element 25 is perpendicular to the illustrated inclined surface provided on the right protrusion 21c of the support member 21, and
0 corresponds to the direction of the light that is reflected by the reflective thin plate 22 and the outer surface 11 and then travels straight into the protrusion 21C of the support member 21. The light-receiving element 25 has a built-in near-infrared photodiode, which becomes conductive upon receiving light and outputs a light-receiving signal.

The cover 26 is made of a light-resistant material such as rubber that does not transmit light, and is formed by a molding method to have the cross section shown in the figure, except for the lower surface of the support member 23 (the surface portion is
4 and the light-receiving element 25, thereby shielding the light-receiving element 25 from disturbance light and enhancing the external appearance of the liquid detector 2o itself. In addition, a lead wire 24a extending from the input terminal of the light emitting element 240 through between the surface of the support member 23 and the inner surface of the cover 26 is inserted into the insertion hole 26a formed at the base of the cover 26 to the output terminal of the light receiving element 25. The lead wire 25a extending from the connector 27 is inserted through the lead wire 25a and connected to the connector 27.

Note that the light emitting diode of the light emitting element 24 is connected to the connector 27.
Lead wire 24 from a control circuit (not shown) connected to
On the other hand, the photodiode of the light-receiving element 25 applies the received light signal to the control circuit through the lead wire 25a as a detection signal necessary for automatic control of the windshield wiper.

In this embodiment configured as above, the liquid detector 2
0 to the windshield 10, as described above, the light emitting element 24 and the light receiving element 25 are assembled to the rain shower parts 23a, 23b of the support member 23, and the reflective thin plate 22 is attached.
is attached to the lower surface of the support member 21, and the lower surface of the support member 23 is adhered to the upper surface of the support member 21, and the cover 2 is attached to the lower surface of the support member 21.
6 removed from the support member 23
is prepared in advance, and the support member 21 of the liquid detector 20 is adhered to the windshield inner surface 12 at its lower surface 21a via the reflective thin plate 22 as described above, and then the support member 23 is covered with a cover 26. The illustrated mounting state of the liquid detector 20 can be easily achieved by simply performing the following steps. In this case, even if the windshield 10 undergoes a change in thermal expansion in relation to the ambient temperature, the support member 21 will not follow the change in thermal expansion of the windshield 10 because it has almost the same coefficient of thermal expansion as the windshield 10. As a result, the lower surface 21a of the support member 21 can be reliably maintained in a bonded state in which it is always closely bonded to the inner surface 12 of the windshield. Further, since the support member 23 is an integrally molded component made of synthetic resin material, it is easy to form, and there is no need for troublesome optical axis alignment work when assembling the light emitting element 24 and the light receiving element 25 to the support member 23. Also, when adhering the support member 23 to the support member 21, the support member 23, That is, the light emitting element 24 and the light receiving element 25
can be easily and precisely positioned with respect to the support member 21.

In the above embodiment, the support member 23 is formed as an integrally molded part, but instead, for example, the support member 23 may be formed as two molded parts by omitting the thin wall portion 23C. , these patterned parts may be adhered to both protrusions 21b and 21c of the support member 21, respectively.

Further, in the above embodiment, the support member 21 is made of a glass material, but the support member 21 is not limited to this, and the windshield 1
Even if the support member 21 is formed of a material having refraction characteristics and thermal expansion characteristics similar to those of 0, it is possible to achieve the same effects as in the above embodiment.

Further, in the above embodiment, an example was explained in which the thin reflective plate 22 was attached to the lower surface 21a of the supporting member 21, but instead of this, the thin reflective plate 22 could be attached to the center of the upper surface of the supporting member 21.
In such a case, the bonding state between the lower surface 21a of the support member 21 and the inner surface 12 of the windshield is further improved.

Further, in implementing the present invention, the windshield 10
The present invention is not limited to, but can also be applied to windshields such as rear windows of vehicles, windshields of aircraft, ships, etc.

As explained above, the liquid detector for the windshield wiper automatic control device according to the present invention has almost the same coefficient of thermal expansion as the windshield and emits light, as shown in the above embodiment. A first support made of a material that transmits light and a second support made of a synthetic resin material are used, and a light-emitting element and a light-receiving element constituting the liquid detector are arranged so that the light emitted from the light-emitting element to the windshield is Since the liquid detector is previously supported above the first support via the second support so as to allow transmission of both the light and the emitted light from the windshield to the light receiving element. to the inner surface of the windshield, it is only necessary to fix the lower surface of the first support in place on the inner surface of the windshield, and in this case, both the first support and the windshield have substantially the same thermal expansion characteristics. Therefore, the bonding surfaces of both of them are always maintained in a securely adhered state regardless of changes in thermal expansion, and as a result, the incidence of light from the light emitting element to the windshield via the first support body or Emission of light from the windshield to the light receiving element via the first support can be reliably realized. Further, since the second support is formed of a synthetic resin material, the dimensions and shape of the second support necessary for supporting the light emitting element and the light receiving element can be easily realized with high precision.

[Brief explanation of the drawing]

The drawing is a sectional view showing a state in which a liquid detector according to the present invention is attached to a windshield of a vehicle. Explanation of symbols 10...windshield, 11...outer surface of windshield, 12...inner surface of windshield, 21.23...
- Supporting member, 24... Light emitting element, 25... Light receiving element. Applicant Nippondenso Co., Ltd. Agent Patent Attorney Teru Hase −

Claims (1)

[Claims] It is provided on a part of the inner surface of the windshield corresponding to the sliding area on the outer surface of the windshield of the wiper blade constituting the windshield wiper, and has a light emitting element and a light receiving element. When there is no liquid attached, the light generated from the light receiving element is incident on the windshield so as to be totally reflected within the windshield, and when there is the attached liquid, the amount of light reflected within the windshield. liquid detection, wherein the light emitted from the windshield after reflection inside the windshield is received by the light receiving element, and the result of the light reception is generated as a detection signal necessary for automatic control of the windshield wiper. a first support member having a lower surface fixed to the inner surface of the windshield, the first support member being formed of a material having substantially the same coefficient of thermal expansion as the windshield and transmitting light; The light-emitting element and the light-receiving element are supported by the first support body so that incident light from the light-emitting element to the windshield and light emitted from the windshield to the light-receiving element are transmitted through the first support. A liquid detector for an automatic windshield wiper control device, characterized in that a second support made of a synthetic resin material is provided above the first support.