JP2002310787A - Sunshine sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sunshine sensor which can solve the problem that, when the conventional sunshine sensor is attached to a dashboard, sunlight is reflected by the light receiving lens of the sensor and reaches the eyes of a crew and, when the surface of the lens is roughened, the measurement accuracy of he sensor drops and the appropriate control of an air conditioner becomes difficult. SOLUTION: This sunshine sensor is composed of a measuring module composed of a plurality of photoreceptor elements 2a-3d, and a light receiving lens 3 covering the elements 2a-2d; and a semispherical reflection preventing lens 4 which coaxially covers the lens 3 at an appropriate interval and has a fixed thickness, and the external surface of which is subjected to diffusion treatment 4b. Consequently, the surface of the sensor 1 can be roughened without exerting any influence upon the substantial measurement accuracy of the sensor 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sunshine sensor used for controlling an air conditioner provided for a vehicle, and more particularly, to measuring an elevation angle of the sun.
For example, when it is determined that direct light from the vehicle window radiates into the vehicle and the occupant feels heat, the occupant is used to perform more precise control such as increasing the output of the air conditioner.

[0002]

2. Description of the Related Art FIGS. 5 and 6 show an example of the configuration of a conventional sunshine sensor 90 of this type. The sunshine sensor 90 has four light receiving elements 91 (a to 91a) arranged in a square.
d) and a substantially hemispherical light receiving lens 92 covering the light receiving elements 91 (a to d).

At this time, when light from the front in the horizontal direction indicated by arrow H in the drawing enters the light receiving lens 92, the light reaches the rear end of the light receiving element 91b (and the light receiving element 91d). By doing so, in this state, most of the light incident on the light receiving lens 92 reaches the light receiving element 91b.

When the elevation angle of the sun gradually increases, the amount of light distributed to the light receiving element 91a also gradually increases. When the elevation angle reaches 90 °, the light receiving element 91b and the light receiving element 91a are increased.
The same light amount is distributed to a. Therefore, if the output of the light receiving element 91a is divided by the output of the light receiving element 91b, the obtained result is substantially proportional to the elevation angle of the sun, that is, the elevation angle of the sun can be measured. still,
When mounting the sunshine sensor 90 on a vehicle, a place that is easily received by sunlight, such as on a dashboard, is often selected.

[0005]

However, in the above-described conventional sunshine sensor 90, since the light receiving lens 92 is formed of a smooth surface, the sunlight is reflected by the surface of the light receiving lens 92. Such light may reach the field of view of the driver or the like, causing a dazzling sensation or disturbing the driving operation, such as distraction.

In order to solve this problem, a means has been proposed in which the surface of the light-receiving lens 92 is subjected to a roughening treatment such as graining to diffuse the reflected light. Accordingly, the light receiving lens 92 is
In addition, the performance of distributing light as an appropriate ratio also decreases, so that the measurement of the solar elevation angle becomes inaccurate, the control accuracy of the air conditioner decreases, and the comfort of the occupants is impaired, which is not an appropriate solution.

[0007]

According to the present invention, there is provided a measuring module comprising a plurality of light receiving elements arranged in a predetermined array and a light receiving lens covering the light receiving elements. And an anti-reflection lens that is coaxial with the light-receiving lens of the measurement module, has a constant thickness, is hemispherical and covers the measurement module with an appropriate gap, and has an outer surface subjected to diffusion processing. By providing a sunshine sensor, the problem is solved by reducing the light reflected by the light receiving lens to the occupant without impairing the measurement accuracy of the sun elevation angle.

[0008]

Next, the present invention will be described in detail based on an embodiment shown in the drawings. 1 and FIG.
Is a sunshine sensor according to the present invention, the sunshine sensor 1 measures the elevation angle of the sun, the azimuth angle to the vehicle,
It is the same as the conventional example in that the air conditioner is mounted on the vehicle to further control the air conditioner according to the situation inside the vehicle.

As a configuration for measuring the elevation angle and azimuth angle of the sun, a plurality of light receiving elements 2 such as four
(Ad) and one substantially hemispherical light-receiving lens 3 that covers these light-receiving elements 2 (ad). The light-receiving lens 3 may be, for example, a meniscus lens. It is. Note that the description here is made of four light receiving elements 2 (a to d) and one substantially hemispherical light receiving lens 3 as in the conventional example.

Here, in the present invention, the light receiving elements 2 (a to
In addition to d) and the light-receiving lens 3, an anti-reflection lens 4 is provided to cover the light-receiving lens 3 in a substantially hemispherical shape. Is performed, the illusion to the occupant is prevented from occurring, and a decrease in measurement accuracy due to the rough surface treatment 4b is prevented.

The anti-reflection lens 4 is formed using a transparent member such as a resin member having a refractive index equal to or higher than that of the light receiving lens 3, and the light receiving lens 3 is hemispherical. In the case, the anti-reflection lens 4
The convex spherical surface 4a is also a concentric hemisphere having a center P at the same position as the light receiving lens 3.

The antireflection lens 4 has a concave spherical surface 4c on the inner surface, and the concave spherical surface 4c also has a center P at the same position as the convex spherical surface 4a. It becomes a hollow dome shape with thickness t,
An air layer 5 having a certain interval exists between the light receiving lens 3 and the light receiving lens 3.

FIG. 3 is a diagram showing the operation of the anti-reflection lens 4. The convex spherical surface 4a of the anti-reflection lens 4 has
Since the rough surface processing 4b has been performed as described above, sunlight (parallel rays) incident on the antireflection lens 4 from, for example, a direction T at an elevation angle of 90 ° is subjected to the rough surface processing 4b.
Will cause diffusion.

The degree of diffusion of the transmitted light (diffusion angle) varies depending on the strength of the rough surface treatment 4b. Here, the degree of diffusion is as follows.
Gaussian diffusion is performed in which the light amount is diffused in a normal distribution with respect to the traveling direction of the light, and the diffusion angle is a diffusion angle with a declination at which the light amount is reduced to 60.6%. The description will be made on the assumption that the Gaussian diffusion is 20 ° which can provide a necessary and sufficient function.

With the above configuration, the elevation angle 9
The sunlight incident on the anti-reflection lens 4 from the direction T of 0 ° is diffused as a Gaussian diffusion angle of 20 ° by the rough surface treatment 4b applied to the convex spherical surface 4a. Will be reached.

The light that has reached the concave spherical surface 4c is refracted more strongly by the concave spherical surface 4c as the angle of deviation from the direction T is larger, and radiates into the air layer 5 inside the concave spherical surface 4c. Is done. However, at this time, the anti-reflection lens 4
The light which is deflected by the rough surface treatment 4b to be equal to or larger than the critical angle of the member on which the surface is formed is subjected to internal reflection toward the inside of the antireflection lens 4 at the boundary surface between the concave spherical surface 4c and the air layer 5. Becomes

Due to the above operation, the light reaching the light receiving lens 3 is limited to the light having a narrow diffusion angle in the light diffused by the rough surface treatment 4b, for example, as Gaussian diffusion 20 °. As a result, the same result as in the case where the slight rough surface treatment 4b is performed is obtained, that is, a decrease in accuracy when measuring the solar elevation angle is reduced.

Here, the spherical radius r1 of the light receiving lens 3
The relationship between the anti-reflection lens 4 and the spherical radius r2 will be described. As is clear from the above description, the larger the spherical radius r2 of the anti-reflection lens 4 is, the narrower the light receiving lens 3 is. Light having a divergence angle, in other words, light close to a parallel ray, is incident, and it is possible to reduce the decrease in measurement accuracy.

Therefore, when a strong surface is required for the rough surface treatment 4b, it is required that (the spherical radius r
2 >> The spherical radius r1) of the light receiving lens 3 may be used. Similarly, when the rough surface treatment 4b is slight, the spherical radius r2 of the antireflection lens 4 can be reduced.

Incidentally, according to the results of trial manufacture and examination by the inventor of the present invention to realize the present invention, when the strength of the rough surface treatment 4b is equivalent to Gaussian diffusion of 20 °, the spherical radius of the antireflection lens 4 is reduced. It was confirmed that good results can be obtained when r2 is at least 2.5 times the spherical radius r1 of the light receiving lens 3.

FIG. 4 shows an elevation angle measurement characteristic S when the antireflection lens 4 according to the present invention is provided, and an elevation angle measurement characteristic Q when the rough surface processing is directly performed on the light receiving lens described in the conventional example.
The graph shows the output ratio between the light receiving element 2b and the light receiving element 2a (the light receiving element 91b and the light receiving element 91a in the conventional example) when the elevation angle changes. Note that the rough surface treatments applied to both have the same Gaussian diffusion intensity of 20 °.

As is clear from the figure, the elevation angle measurement characteristic Q when the light receiving lens is directly roughened has an output ratio of about 0.5 when the sun elevation angle changes from 0 ° to 90 °.
In contrast to 6: 1, the output ratio is improved to about 0.4: 1 in the elevation angle measurement characteristic S when the antireflection lens 4 is provided, in other words, from 1.5 times to 2.5 times. And the amount of change per elevation angle is increasing.

Considering the elevation angle measurement characteristic S, the numerical value of the output ratio 0.4: 1 is the elevation angle measurement characteristic by only the light receiving elements 2 (a to d) and the light receiving lens 3. Is very similar to the numerical value obtained by the above equation, and the numerical value at the halfway angle from the elevation angle of 0 ° to 90 ° also agrees very well.

This is because the antireflection lens 4 is newly provided according to the present invention, and the outer surface (convex spherical surface 4a) of the antireflection lens 4 is roughened 4b. It is possible to apply a rough surface treatment to the outer surface of the sunshine sensor 1 without lowering it, thereby improving both measurement accuracy and anti-glare performance, which were conventionally contradictory factors. Becomes

[0025]

As described above, according to the present invention, a measuring module comprising a plurality of light receiving elements arranged in a predetermined arrangement and a light receiving lens covering the light receiving element, and a coaxial with the light receiving lens of the measuring module The measurement module is made of a sunshine sensor composed of a hemispherical lens having a constant thickness, which is covered with an appropriate gap, and an anti-reflection lens whose outer surface is subjected to diffusion treatment, thereby substantially affecting measurement accuracy. In addition, it is possible to perform a rough surface treatment so that the driver does not have a sense of dazzling or the like, and to achieve an extremely excellent effect in improving the performance of this type of sunshine sensor.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of a sunshine sensor according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an explanatory diagram showing the operation of the sunshine sensor according to the present invention in a main part.

FIG. 4 is a graph showing elevation angle measurement characteristics of the sunshine sensor according to the present invention in comparison with a conventional example.

FIG. 5 is a plan view showing a conventional example.

FIG. 6 is a sectional view taken along line BB of FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Sunshine sensor 2 (ad) ... Light receiving element 3 ... Light receiving lens 4 ... Anti-reflection lens 4a ... Convex spherical surface 4b ... Rough surface treatment 4c ... Concave spherical surface

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshihiro Oikawa 2-9-13-1 Nakameguro, Meguro-ku, Tokyo Inside Stanley Electric Co., Ltd. (72) Inventor Takuya Kushimoto 2-9-1-13 Nakameguro, Meguro-ku, Tokyo No. Within Stanley Electric Co., Ltd. (72) Inventor Masanori Ohno 2-9-13 Nakameguro, Meguro-ku, Tokyo F-term within Stanley Electric Co., Ltd. 2G065 AA03 AA15 AA17 AB04 BA01 BA34 BB05 BB06 DA20

Claims (1)

[Claims] A measuring module comprising: a plurality of light receiving elements arranged in a predetermined arrangement; and a light receiving lens covering the light receiving element;
An insolation sensor comprising an anti-reflection lens having a hemispherical shape having a constant thickness and covering the measuring module with an appropriate gap, and having an outer surface subjected to a diffusion treatment.