JPH0220721Y2 - - Google Patents

Description

[Detailed Description of the Invention] <<Industrial Application Field>> This invention relates to a lamp used in a vehicle such as an automobile, and particularly to a vehicular lamp equipped with a detection device for detecting dirt on the front lens of the lamp.

<Prior Art> Conventionally, in vehicle lamps used in vehicles such as automobiles, a detection device for detecting dirt on the front lens of the lamp is installed on the outside of the lamp, or inside the lamp. Either structure is configured to optically detect dirt.

However, in a structure in which the detection device is disposed outside the lamp, there are problems in that the detection device itself becomes dirty and its detection power decreases, and the portion protruding from the vehicle body is easily damaged. On the other hand, a structure in which the detection device is placed inside the lamp does not have such a problem.

Therefore, a vehicle lamp in which a detection device is disposed inside the lamp can be seen in, for example, Japanese Utility Model Application Publication No. 165256/1983. In this structure, a detection device is installed inside the lamp, and a switch that is electrically connected to this detection device and turns on when the dirt on the lens reaches a certain level activates the cleaner to clean it. It is something.

Further, there is a vehicle lamp having a structure as shown in FIG. 3 as a vehicle lamp in which a detection device is disposed within the lamp to simply detect dirt. The vehicle lamp 1 shown in FIG. 3 includes a housing 2, a reflector 3, a bulb 5 attached to a socket 4, a lens 6 attached to cover the front opening of the housing 2, and arranged inside the housing 2. It is equipped with a detection device 7 and the like.

The detection device 7 consists of a photocoupler 8 consisting of an infrared light emitting element 11 and a phototransistor 12, and a hard printed circuit board 9 on which a plurality of control circuit elements (not shown) are mounted. Each of the 12 terminals is soldered to a circuit terminal portion on the printed circuit board 9.

Further, the photocoupler 8 is arranged behind the reflector 3 and at a position corresponding to the hole 3A formed in the reflector 3. Then, infrared light is emitted from the infrared light emitting element 11 of the photocoupler 8, and the emitted infrared light is emitted onto the lens 6 through the hole 3A. The infrared light irradiated onto the lens 6 in this manner is reflected by the housing outer boundary surface 6A of the lens 6, and the reflected light is received by the phototransistor 12 and converted into a detection signal.

FIG. 5 shows a control circuit applicable to the detection device 7. In FIG. 5, reference numeral 14 denotes a drive circuit connected in parallel with the power supply 13. The infrared light emitting element 11 is connected to the output terminal of this drive circuit 14, and the infrared light emitting element 11 is periodically supplied from the drive circuit 14. The infrared light emitting element 11 periodically emits light with the output. In addition, a resistor 15 is connected to the power supply 13.
A phototransistor 12 is connected in parallel through the phototransistor 12, a detection circuit 16 including an amplifier is connected to the collector of the phototransistor 12, and an output terminal 18 is connected to the output terminal of the detection circuit 16.
An output circuit 17 is connected thereto.

In the detection device 7 using the control circuit configured in this way, when the infrared light emitting element 11 periodically emits light under the control of the drive circuit 14, this light is transmitted to the outer boundary surface 6A of the housing of the lens 6. It is reflected and incident on the phototransistor 12. When the outer surface of the lens becomes dirty with mud, etc., the infrared light reflected by the housing outer boundary surface 6A is attenuated, and the output V1 of the phototransistor 12 changes by ΔV as shown in FIG. . This change in output ΔV is detected by a detection circuit 16, and further taken out via an output circuit 17 to detect dirt on the external surface of the lens.

In the embodiment shown in FIG. 3, the housing outer boundary surface 6A and the housing inner boundary surface 6B
The infrared light emitting element 11 and the phototransistor 12 are arranged in a very close position.

Therefore, in the detection device 7 having such a configuration,
The light emitted from the infrared light emitting element 11 is geometrically optically divided into the light reflected by the housing outer boundary surface 6A of the lens 6 and the third
As shown by the dashed line in the figure, the light reflected from the housing inner boundary surface 6B of the lens 6 is incident on the phototransistor 12. That is, in FIG. 3, a circle A drawn with a solid line surrounding the phototransistor 12 is the irradiation range of light reflected from the housing outer boundary surface 6A, and a circle B drawn with a dashed line is the irradiation area of the housing inner boundary surface 6B. This is the irradiation range of the light reflected by the However, the light reflected by the housing inner boundary surface 6B is essentially noise, and is reflected light that should not be incident on the phototransistor 12 in order to improve detection accuracy.

In the conventional detection device 7 that simultaneously receives the light reflected by the housing outer boundary surface 6A and the light reflected by the housing inner boundary surface 6B, as shown in FIG. Of the output V1, V0 is the output corresponding to the light reflected from the housing outer boundary surface 6A, and the other half of the output U0 is the output corresponding to the light reflected from the housing inner boundary surface 6A.
The output corresponds to the light reflected from B.

<<Problems to be Solved by the Invention>> As described above, in the conventional detection device 7, which receives both the light reflected from the housing outer boundary surface 6A and the housing inner boundary surface 6B by the phototransistor 12, it is difficult to avoid "contamination". Since the change ΔV between the output when there is no stain and the output when there is dirt attached is small, there is a problem in that the detection sensitivity is poor and good detection accuracy cannot be obtained. In addition, the housing inner boundary surface 6B
Since the housing outer boundary surface 6A and the housing outer boundary surface 6A are formed as substantially parallel surfaces, the hole 3A of the reflector 3 and the photocoupler 8 are directly viewed from outside the lens 6, resulting in a problem that the appearance of the lamp 1 becomes poor.

The present invention was devised in view of these conventional problems, and it is an object of the present invention to provide a structure for a vehicle lamp that can improve the detection sensitivity of a detection device that detects lens dirt and also improves the appearance of the lamp. With the goal.

<Means for Solving the Problems> In order to achieve the above objects, the present invention provides a detection light source that irradiates detection light toward the inner boundary surface of the housing of the lens, which is arranged with the front opening of the housing closed. and a photocoupler that receives the detection light incident from the inner boundary surface and reflected by the outer boundary surface of the housing of the lens and converts it into an electric signal, the vehicle lamp comprising: The lens is characterized in that the inner boundary surface and the outer boundary surface are formed at an angle to each other so that the direction of the detection light reflected by the inner boundary surface and the outer boundary surface is different. .

<<Operation>> In the vehicle lamp with the above configuration, the inner boundary surface of the lens housing and the outer boundary surface of the housing are formed at an angle with each other, and the detected light reflected by the inner boundary surface of the housing and the outer boundary surface of the housing is formed. Since the orientations of the light receiving elements are different, by placing the light receiving element at the position of the reflected light reflected from the outer boundary surface of the housing, the reflected light reflected from the inner boundary surface of the housing, which becomes noise, is incident on the light receiving element. Since it is possible to prevent this from occurring, detection sensitivity can be improved. Furthermore, the inclination between the inner boundary surface of the housing and the outer boundary surface of the housing acts as a prism, making it difficult for the detection light emitting source and the light receiving element to be viewed directly from outside the lens, thereby improving the appearance of the lamp.

<<Example>> Hereinafter, an example of the vehicle lamp according to the present invention will be described with reference to the drawings.

FIG. 1 shows a vehicle lamp 21 according to the present invention, which includes a housing 22, a reflector 23, a bulb 25 attached to a socket 24, a lens 26 attached so as to close the front opening of the housing 22, and a housing 22. It includes a detection device 27 and the like arranged inside.

The detection device 27 is similar to that used in the vehicle lamp shown in FIG. It consists of a hard printed circuit board 9 on which a control circuit element (not shown) is mounted, and each terminal of an infrared light emitting element 11 and a phototransistor 12 is soldered to a circuit terminal portion on the printed circuit board 9.

Further, the photocoupler 8 is placed behind the reflector 23 and in a hole 23A formed in the reflector 23.
are placed in corresponding positions. Then, infrared light is emitted from the infrared light emitting element 11 of the photocoupler 8, and the emitted infrared light is emitted onto the lens 26 through the hole 23A. This infrared light emitting element 1
The part on the lens 26 that receives the irradiated light from 1 is
The housing outer boundary surface 26A and the housing inner boundary surface 26B are formed in a prismatic shape with an angle θ to each other.

Therefore, by forming the prism shape, in the infrared light emitted from the infrared light emitting element 11, the lens 26 can be removed from the housing inner boundary surface 26B.
As shown by the solid line in Figure 1, the incident light is once refracted by the prism effect of the lens 6, then proceeds directly to the housing outer boundary surface 26A, and after being refracted by the housing outer boundary surface 26A, it emits infrared light. The area of a circle A centered on the phototransistor 12, which is arranged at a relatively large distance from the element 11 in the lateral direction, is irradiated. Further, a part of the infrared light emitted from the infrared light emitting element 11 is incident on the housing inner boundary surface 26B, and as shown by the dashed line in FIG. The area of a circle B centered on the light emitting element 11 is irradiated. That is, the infrared light incident on the phototransistor 12 is blocked by the hole 23A of the reflector 23, and the infrared light enters the outer boundary surface 26 of the housing.
Only the effective light reflected at A is incident.

The detection device 27 formed in this way has a fifth
The control circuit shown in the figure is applied. That is, in the detection device 27 using the control circuit shown in FIG. Only the incoming light is mainly incident on the phototransistor 12. The output V1 of this phototransistor 12 is
When the external surface of the device 6 is not contaminated, it outputs an output V0+U0 in the "no soiling" range as shown in FIG. On the other hand, if the outer surface of the lens becomes dirty with mud, etc., the infrared light reflected from the outer boundary surface of the housing will be attenuated, and the output V1 of the phototransistor 12 will be reduced.
outputs an output (V0 - △V) + U0 in the "dirt adhesion" range as shown in the second figure. Change in this output △
V is detected by the detection circuit 16, and further, the output circuit 17
By taking it out through the lens, dirt on the external surface of the lens is detected.

As shown in FIG. 2, this detection device 2
7, the housing outer boundary surface 26
There is almost no noise U0 other than the light reflected by A, so the output when there is no dirt and the output when there is dirt attached
As the output change ΔV increases, the sensitivity improves, and dirt on the external surface of the lens 26 can be detected accurately. Further, since the space between the housing outer boundary surface 26A and the housing inner boundary surface 26B of the lens 26 is formed in a prism shape, when viewed from the front of the lens 26, the infrared light emitting element 11 and the phototransistor can be connected to each other by this prism. 12 becomes difficult to see directly, and their arrangement is not noticeable from the outside.

In this example, an infrared light emitting element is used as the detection light source and a phototransistor is used as the light receiving element, but the present invention is not limited to these, and includes a wide range of light emitting elements including lamps and photoelectric conversion elements. It is possible to use a light receiving element etc. as necessary.

<<Effect of the invention>> As explained above, according to the vehicle lamp of the present invention, the detection sensitivity of the detection device for detecting dirt on the lens is improved, and the detection device can be used without impairing the appearance of the lamp. can be provided.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing one embodiment of a vehicle lamp according to the present invention, FIG. 2 is an output waveform diagram of a detection device built into the vehicle lamp shown in FIG. 1, and FIG. 3 is a diagram of a conventional vehicle lamp. A vertical cross-sectional view showing an example of a vehicle lamp, FIG. 4 is an output waveform diagram of a detection device built into the vehicle lamp shown in FIG. 3, and FIG. FIG. 2 is a circuit diagram showing an example of a control circuit applicable to a detection device built into a lamp. 21...Vehicle lamp, 22...Housing, 2
6...Lens, 26A... Lens housing outer boundary surface, 26B... Lens inner boundary surface, 27
. . . Detection device, 8 . . . Photocoupler, 11 .

Claims (1)

[Scope of utility model registration request] a detection light source that irradiates detection light toward the inner boundary surface of the housing of the lens, which is disposed with the front opening of the housing closed; A vehicular lamp equipped with a photocoupler comprising a light receiving element that receives detection light and converts it into an electrical signal, wherein the inner boundary surface and the outer boundary surface of the lens are formed at an angle to each other, and the A vehicular lamp characterized in that the direction of the detection light reflected by the inner boundary surface and the outer boundary surface is different.