JP2827763B2 - Solar radiation sensor for automotive air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar radiation sensor for detecting the amount of solar radiation, converting the amount of solar radiation into a signal necessary for controlling the air conditioner, and outputting the signal in an automotive air conditioner.

[0002]

2. Description of the Related Art A solar radiation sensor of an air conditioner for a vehicle is generally mounted on an instrument panel in a passenger compartment, detects the intensity of sunlight and outputs a signal for controlling the air conditioner. Is required to output a signal corresponding to the amount of heat of sunlight and radiation caused by sunlight felt by the occupant.

Hereinafter, an example of a solar radiation sensor of a conventional automotive air conditioner will be described with reference to the drawings.

FIG. 6 shows the structure of a solar radiation sensor of a conventional automotive air conditioner. In FIG. 6, reference numeral 11 denotes a photodetector, which includes a photodetection element 12, detects the amount of solar radiation and outputs a signal corresponding to the solar radiation. 13 is a lens and a photodetector 1
It also has the function of a lens that collects light and the design function to improve the appearance when it is attached to the instrument panel in the passenger compartment.

[0005]

However, in the above configuration, most of the light incident from the vertical direction of the photodetector 11 reaches the photodetector 12. On the other hand, the light incident from the horizontal direction is bent by the lens 13 and a part thereof reaches the light detecting element 12, but the amount thereof is very small.

FIG. 7 is a diagram showing a change in the amount of light detected by the incident angle when the irradiation light amount (sunlight) is constant, that is, a change in the output value of the solar radiation sensor.

When the incident angle is 90 °, that is, when the amount of light detected from the vertical direction of the photodetector 11 is 100, the incident angle is 0 °, that is, when the light is incident from the horizontal direction of the photodetector 11, the value is 0. It will be a close value. That is, when a conventional concave lens composed of a spherical surface is used as a lens, the incident light has a high dependency on the incident angle, and depending on the position (altitude) of sunlight,
Even with the same amount of sunlight irradiation, the output value of the solar radiation sensor changes greatly. Particularly, at a low incident angle, almost no detection is performed, and there is a problem that the air conditioner cannot be accurately controlled according to the amount of solar radiation.

Further, the degree of influence of the amount of heat perceived by the occupant due to the sunlight varies depending on the difference in the altitude of the sun even for the same amount of solar radiation, and also varies variously depending on the shape of the automobile, the shape of the vehicle interior members, the material, etc. The characteristics required for, including the mounting position of the solar radiation sensor and the positional relationship with the occupant,
Each type of vehicle is different, and in providing a solar radiation sensor for a vehicle air conditioner, it is necessary to easily cope with various required characteristics.

Therefore, as disclosed in JP-A-1-316618 and JP-A-2-112735, means for obtaining necessary output characteristics of a solar radiation sensor using transmission, reflection and refraction of a lens is considered. Can be

For example, a solar radiation sensor as shown in FIG. 1 will be described with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a photodetector, which includes a photodetector element 2. The photodetector 1 detects the amount of solar radiation striking the photodetector 2, and outputs a signal corresponding to the intensity of the amount of solar radiation. Output. This signal is sent to the control unit of the air conditioner, and the air conditioner is controlled in consideration of the amount of solar radiation. Reference numeral 3 denotes a lens, which comprises a light source side surface (lens outer surface) 4 and a photodetector side surface (lens inner surface) 5, the surface of which is usually finished with a roughness of 1 μ or less.

The function of the lens 3 of the solar radiation sensor configured as described above will be described. FIGS. 2A and 2B
(C) shows how the light source at each incident angle reaches the light detecting element 2. When the light source is right above, that is, when the incident angle is 90 °, as shown in FIG. 2A, the slope 5a of the photodetector side face 5 reflects the incident light, and the light on the photodetector side face 5 is reflected. Only light incident from the plane portion 5b parallel to the surface of the detection element 2 reaches the light detection element 2. When the light source is obliquely upward, that is, when the incident angle is, for example, 45 °, the light incident on the slope 5a reaches the photodetector 2 as shown in FIG. When the light source is right beside, that is, when the incident angle is 0 °, the light incident on the surface 5c of the photodetector side surface 5 perpendicular to the surface of the photodetector 2 as shown in FIG. Reach 2. Therefore, a lens having various characteristics can be provided by changing the length and inclination of the slope portion 5a, the area of the flat portion 5b, and the length of the vertical surface 5c.

However, in the manufacture of lenses, even slight dimensional variations and surface finish variations (including sink marks and warpage on molding) change the transmission and refraction characteristics of light.
In order to manufacture a lens having the output characteristics that are actually required, highly sophisticated techniques such as mold accuracy and molding accuracy are required, and the cost is higher than that of a conventional lens.

Further, the output characteristics of the solar radiation sensor are combined into a single output characteristic by combining the characteristics of the inner and outer surfaces of the lens constituting the lens, so that even if the output characteristics are slightly changed, the output characteristics are complicated. The lens design had to be redone from the beginning, and it took a considerable amount of time for the design to change even slightly.

[0015] Therefore, there has been a demand for a means for facilitating manufacture and making it possible to easily change a small output characteristic.

[0016]

In order to achieve the above object, a solar radiation sensor for a vehicle air conditioner according to the present invention has
A lens consisting of multiple surfaces with different angles to the photodetector
To obtain a predetermined output characteristic with respect to the incident angle of light
Configure and part of the inner surface of the lens has its surface roughened
The output characteristic is adjusted by providing a rough surface portion.

[0017]

According to the present invention, the amount of light that reaches the photodetector by transmitting, reflecting, or refracting incident light through the lens is controlled by the above-described structure, and is most suitable for the target vehicle type. An insolation sensor having an output characteristic capable of controlling the air conditioner according to the occupant's feeling can be easily manufactured at low cost.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG. As described above, in FIG. 1, reference numeral 1 denotes a photodetector, which includes at least one photodetector 2. The photodetector 1 detects the amount of solar radiation hitting the photodetector 2, and detects the amount of solar radiation. Outputs a signal according to the strength of. This signal is sent to the control unit of the air conditioner, and the air conditioner is controlled in consideration of the amount of solar radiation. Reference numeral 3 denotes a lens. The lens 3 includes a light source side surface (lens outer surface) 4 and a photodetector side surface (lens inner surface) 5.

Regarding the lens 3 of the solar radiation sensor configured as described above, both the light source side surface (lens outer surface) 4 and the photodetector side surface (lens inner surface) 5 of the lens 3 have normal lens surface finishing accuracy. In this case, the output characteristics of the solar radiation sensor with respect to the incident angle of light are as shown in FIG. 3 due to the transmission, reflection and refraction properties of the lens 3.

If the output value per 80 ° to 90 ° of the incident angle of light is to be reduced in relation to the shape of the roof of the automobile or the position where the solar radiation sensor is mounted, the conventional method uses the light on the side surface 5 of the photodetector. This can be achieved by reducing the area of the plane portion 5b parallel to the surface of the detection element 2. In this case, it is physically necessary to configure the slope portion 5a of the photodetector side surface 5 at the same position as in the related art. It becomes impossible, and as a result, the slope portion 5a changes, so that the characteristics of the solar radiation sensor change even in a region where the incident angle of light is 80 ° or less, and it is necessary to redesign the lens.

By the way, if the surface finish of the lens is rough,
A phenomenon occurs that transmitted light causes irregular reflection on the surface of the lens. Now, if irregular reflection occurs on the plane portion 5b parallel to the surface of the photodetector 2 on the photodetector side surface 5 in FIG. 1, the amount of light that passes through the plane portion 5b and reaches the photodetector 2 decreases. Therefore, the output value of the solar radiation sensor decreases. Therefore, the output value per 80 ° to 90 ° of the incident angle of light can be reduced by making the plane portion 5b entirely or partially rough, and the width of reduction can be set according to the degree of roughness and the range of roughening. It is possible to easily provide a solar radiation sensor having a relative output characteristic as shown in FIG.

On the contrary, from the incident angle of light of 0 ° to 2
In order to increase the output characteristic per 0 °, the irregular reflection characteristic of the light on the lens surface described above is used in reverse, and the light of the lens 3 which affects the output value of the solar radiation sensor at an incident angle of 0 ° to 20 ° is used. By making the photodetector side surface 5 rough except the surface 5c perpendicular to the surface of the photodetecting element 2 on the detector side surface 5, the output value of the solar radiation sensor for light having an incident angle of about 30 ° or more decreases. . Then, as a result, the relative output characteristic of the solar radiation sensor increases from the incident angle of light of about 0 ° to about 20 °, and for example, a solar radiation sensor having the relative output characteristic as shown in FIG. 5 can be provided.

Also, if the output characteristics of the solar radiation sensor partially differ from the required characteristics because the dimensional finishing accuracy of the mold is poor or the surface finishing accuracy is poor,
A part of the lens photodetector side surface 5 related to the incident angle of light having different characteristics can be easily dealt with by changing the surface roughness in the same manner as in the above two examples.

Although all of the above-described examples have been achieved by means of partially roughening the surface of the photodetector side surface 5 of the lens 3, the same effect can be expected on the light source side surface 4. However, if the surface roughness of the light source side surface 4 of the lens 3 is partially changed, the light source side surface 4 becomes a part that can be seen by an occupant when mounted on an automobile, which is not preferable in terms of design. When the part is roughened, the range of the affected incident angle is generally wider than when the roughened part is set on the side of the photodetector, so the side of the photodetector that can easily limit the range of the incident angle is more easily formed. The effect can be exhibited.

[0025]

As described above, according to the present invention, the inner surface is provided with a photodetector.
Light from multiple lenses with different angles
Is configured to obtain a predetermined output characteristic with respect to the incident angle of
Provide a rough surface part with a rough surface on a part of the inner surface of the lens,
By adjusting the output characteristics, a solar radiation sensor having an output characteristic suitable for the amount of heat such as solar radiation and radiation by sunlight felt by the occupant can be manufactured without advanced technology in mold accuracy and molding accuracy, and output can be achieved. Since it is possible to easily cope with a case where the characteristics are slightly changed, it can be provided at a low cost and quickly.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a solar radiation sensor of a vehicle air conditioner serving as a base of the present invention.

FIG. 2A is a cross-sectional view illustrating a state of light incident on the solar radiation sensor at an incident angle of 90 °. FIG. 2B is a cross-sectional view illustrating a state of light incident on the solar radiation sensor at an incident angle of 45 °. ) Is a sectional view showing a state of light incident on the solar radiation sensor at an incident angle of 0 °.

FIG. 3 is a characteristic diagram showing a relationship between a light incident angle and a relative output value of a solar radiation sensor serving as a base of the present invention.

FIG. 4 is a characteristic diagram showing a relationship between a light incident angle and a relative output value of the solar radiation sensor according to one embodiment of the present invention.

FIG. 5 is a characteristic diagram showing a relationship between a light incident angle and a relative output value of a solar radiation sensor according to another embodiment of the present invention.

FIG. 6 is a cross-sectional view of a solar radiation sensor of a conventional automotive air conditioner.

FIG. 7 is a characteristic diagram showing a relationship between a light incident angle and a relative output value of a conventional solar radiation sensor.

[Explanation of symbols]

 Reference Signs List 1 photodetector 2 photodetector 3 lens 4 light source side surface (lens outer surface) 5 photodetector side surface (lens inner surface) 5a slope portion 5b flat portion 5c vertical surface

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Tsugio Sakamoto 1006 Kazuma Kadoma, Kazuma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References Japanese Utility Model Hei 5-87535 (JP, U) (58) Field (Int.Cl. ⁶ , DB name) G01J 1/02-1/04 B60H 1/00 101

Claims (1)

(57) [Claims] 1. A photodetector, the photodetector source side provided <br/> et al are of, and a plurality of different inner surface angles with respect to said photodetector
With a lens consisting of
In a solar radiation sensor configured to obtain output characteristics,
Provide a roughened surface with a rough surface on a part of the inner surface of the lens
A solar radiation sensor for a vehicle air conditioner , wherein the output characteristics are adjusted .