JP4598981B2 - Sunshine sensor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sunshine sensor used when controlling an air conditioner provided for a vehicle, and more specifically, measures the elevation angle of the sun, for example, direct light from a vehicle window enters the vehicle, When it is determined that the occupant feels hot, it is used to perform more precise control such as increasing the output of the air conditioner.
[0002]
[Prior art]
An example of the configuration of this type of conventional sunshine sensor is disclosed in Japanese Patent Application Laid-Open No. 9-311070. This sunshine sensor has two light receiving elements, a convex spherical surface on the outside, and three stages on the inner surface. The light receiving lens is shaped in combination with the prisms.
[0003]
By doing so, light reaches the light receiving element from when the sun is in the vertical direction to when it is almost in the horizontal direction, and at this time, an output difference corresponding to the elevation angle is generated between the two light receiving elements. Therefore, the comfort of the passenger compartment is further improved by controlling the air conditioner based on this output difference.
[0004]
[Problems to be solved by the invention]
However, in the above-described conventional sunshine sensor, the light receiving lens is shaped like a combination of three-stage prisms, so that, for example, the sun is directly above, horizontally, or at an elevation angle around 45 °. In some cases, it is possible to measure an almost accurate sun elevation angle, but in the middle of these, the discontinuous shape of the inner surface is bent, and the measured elevation angle value is also discontinuous.
[0005]
This is because, in the state of the intermediate elevation angle as described above, for example, the output of the air conditioner is not increased in spite of the sunlight entering from the car window, and the occupant feels the heat due to the direct sunlight that enters. There is a high possibility that problems such as loss of comfort will occur, and the solution of this point has been a problem. Further, in the above-described conventional sunshine sensor, since the light receiving element and the light receiving lens are formed as separate bodies, there is a problem that the assembling accuracy at the time of assembling as a sunshine sensor has an effect and individual differences are caused in the characteristics.
[0006]
[Means for Solving the Problems]
As a specific means for solving the above-described conventional problems, the present invention includes a plurality of light receiving elements arranged as a predetermined pattern, and a light receiving lens that covers these light receiving elements from above. In the sunshine sensor that measures the elevation angle of the sun by comparing the amount of light distributed to each of the light receiving elements, the light receiving lens has a fisheye lens shape having elements that match the number of the light receiving elements, and each of the elements corresponds to A convex spherical surface that is coaxial with a vertical axis passing through the center of the light receiving element and has a radius sufficient to accommodate the light receiving element, and the vertex of each element passes through the center of the corresponding light receiving element. located on the vertical axis, the spacing H between the apex of each element receiving surface of each light receiving element, the radius of the inscribed circle of the light receiving elements W, the light receiving lens When a critical angle α of each element surface, H = a W / tan [alpha, solve the problem by providing a sunshine sensor, wherein the plurality of light receiving elements and the light receiving lens are integrated To do.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Below, this invention is demonstrated in detail based on embodiment shown in a figure. 1 and 2 indicate a sunshine sensor according to the present invention. The sunshine sensor 1 includes, for example, four light receiving elements 2 (a to d) arranged in a predetermined shape such as a square, The light receiving lens 3 that covers the light receiving elements 2 (a to d) is the same as the conventional example.
[0008]
The light receiving lens 3 distributes the amount of light corresponding to the elevation angle to the light receiving element 2 (for example, the light receiving element 2a and the light receiving element 2b) in the front-rear direction with respect to the irradiation direction of the sun, for example. The elevation angle can be calculated from the output difference between the light receiving elements 2 that occurs, as in the conventional example.
[0009]
Here, in the sunshine sensor 1 of the present invention, unlike the conventional example in which the plurality of light receiving elements 2 (a to d) are covered with one light receiving lens 3, one light receiving element 2 (a to d) has one. The element 3a to the element 3d are formed to correspond to each other, and the entire shape of the light receiving lens 3 in which the elements 3 (a to d) are integrated is a fisheye lens. .
[0010]
Below, the structure of the said light receiving element 2 (ad) and the element 3 (ad) is demonstrated still in detail. In this description, the light receiving element 2a and the light receiving element 2b, and the element 3a and the element 3b are described, but the light receiving elements 2 (c, d) and the elements 3 (c, d) other than the above have the same configuration. Has been.
[0011]
As shown in FIG. 2, the element 3a is a convex spherical surface that is coaxial with the vertical axis X passing through the center of the light receiving element 2a. The radius r at this time is in a positional relationship with the light receiving element 2a described below. The light receiving element 2a covers the entire surface at least from the light receiving direction, and both the element 3b and the light receiving element 2b have the same configuration.
[0012]
Accordingly, the vertex P of the element 3a is located on the vertical axis X passing through the center of the light receiving element 2a, and similarly, the vertex P of the element 3b is located on the vertical axis X passing through the center of the light receiving element 2b. . Here, in the present invention, the distance H between the apex P and the light receiving element 2 (a, b) is defined based on the formula (interval H = (effective radius W / tan (critical angle α) of the light receiving element)). It is.
[0013]
Here, the effective radius W of the light receiving element 2 is a radius of an inscribed circle of the light receiving element 2 which is usually a square, and the critical angle α is a member of which the elements 3a and 3b (that is, the light receiving lens 3) are formed. The value determined by the refractive index, and by setting the interval H in this way, light incident on the element 3a from the direction perpendicular to the vertical axis X indicated by the arrow F in FIG. The end of the element 2a opposite to the incident direction is reached.
[0014]
Therefore, although the center C of the element 3a exists on the vertical axis X, it does not necessarily coincide with the surface of the light receiving element 2a. For example, the refractive index of the member on which the element 3a is formed is small. In this case, the interval H is also a small value, and the light receiving element 2a is installed closer to the apex P than the center C. Therefore, in such a case, the element 3a needs to appropriately adjust the radius r so that the light receiving element 2a can be completely covered even when the interval H from the apex P is set short as described above. Will occur.
[0015]
Next, the operation and effect of the sunshine sensor 1 of the present invention configured as described above will be described. First, when the sun is in a horizontal position, when light enters from the horizontal direction F, the light reaching the element 3a is refracted by the element 3a as shown in FIG. The light reaches the entire surface.
[0016]
At this time, since the element 3b exists in front of the irradiation direction of sunlight, the element 3b does not reach the shadow of the element 3a, so that sunlight does not reach. Therefore, the light receiving element 2b attached to the element 3b. Does not produce any output. Therefore, the output ratio between the light receiving element 2a and the light receiving element 2b when the elevation angle of the sun is horizontal is 1: 0.
[0017]
As the sun's elevation angle increases, the light reaches the element 3b, and the output from the light receiving element 2b gradually increases as the elevation angle increases, so that the sun's elevation angle is vertical (90 °). The light receiving element 2a and the light receiving element 2b produce the same output, that is, the output ratio is 1: 1.
[0018]
FIG. 3 is a graph in which the output ratio N between the light receiving element 2a and the light receiving element 2b described above is plotted for each elevation angle of the sun. When the curve of the output ratio N is examined in detail, they are adjacent to each other. The values do not become the same between the elevation angles, and the curves are ascending to the right with no extremely steep changes in inclination, so that each elevation angle can be measured almost accurately. Understandable.
[0019]
Further, in the sunshine sensor 1 of the present invention configured as described above, unlike the conventional example, there is no air layer between the light receiving lens 3 (elements 3a to 3d) and the light receiving elements 2a to 2d, Both are integrated. This means that, for example, when the LED lamp is formed, the sunshine sensor 1 can be formed by means using a mold similar to the case where the case is formed on the LED chip by epoxy resin potting mold.
[0020]
This is because the assembly process from the manufacturing process of the sunshine sensor 1 can be omitted, the production efficiency can be improved, and the use of a mold or the like enables accurate alignment with both, and individual differences in the individual sunshine sensors 1 In other words, it is possible to reduce variation in characteristics. In addition, since this kind of sunshine sensor 1 is normally installed in the dashboard of a motor vehicle, etc., since the light receiving lens 3 is formed as a combination of smaller elements 3a to 3d, reflection of sunlight, etc. This reduces the degree of driver's illusion. Accordingly, even when antireflection processing such as embossing is performed on the light receiving lens 3, it may be light and does not impair measurement accuracy.
[0021]
【The invention's effect】
As described above, according to the present invention, the light-receiving lens has a fish-eye lens shape having elements that match the number of light-receiving elements, and each element has its axis aligned with the center of the corresponding light-receiving element and houses this light-receiving element. And a distance H between the apex of the element and the light receiving surface of the light receiving element is (space H = (effective radius W / tan (critical angle α) of the light receiving element)). By adopting a sunshine sensor in which the light receiving element and the light receiving lens are integrated, it is possible to obtain an output that is approximately proportional to the increase or decrease of the sun's elevation angle. As a device that can perform such control, it has an extremely excellent effect on improving passenger comfort.
[0022]
In addition, the structure of the present invention makes it possible to integrally form the light receiving lens and the light receiving element, and has an effect of reducing cost by simplifying the production process. Assuming that no error or the like occurs and the variation in characteristics between the sunshine sensors is remarkably small, an excellent effect can be obtained in improving quality and performance.
[Brief description of the drawings]
FIG. 1 is a front view showing an embodiment of a sunshine sensor according to the present invention.
FIG. 2 is a cross-sectional view taken along the line AA in FIG.
FIG. 3 is a graph showing output characteristics of a sunshine sensor according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Sunlight sensor 2 (a-d) ... Light-receiving element 3 ... Light-receiving lens 3a-3d ... Element X ... Vertical axis P ... Vertex H ... Distance between vertex and light-receiving element r ... Element Radius W: Effective radius of light receiving element

Claims (2)

It consists of a plurality of light receiving elements arranged as a predetermined pattern and a light receiving lens that covers these light receiving elements from above, and measures the elevation angle of the sun by comparing the amount of light distributed to each light receiving element by the light receiving lens In the sunshine sensor, the light receiving lens has a fish-eye lens shape having elements that match the number of the light receiving elements, and each of the elements is coaxial with a vertical axis passing through the center of the corresponding light receiving element. It is a convex spherical surface having a required sufficient radius to, and the apex of each element is located on the vertical axis passing through the center of the corresponding light-receiving elements, the light receiving of the vertex of each element the respective light receiving elements H = W / tan α where the distance H from the surface is W, the radius of the inscribed circle of each light receiving element is W, and the critical angle α of each element surface of the light receiving lens The sunshine sensor, wherein the plurality of light receiving elements and the light receiving lens are integrated. 2. The sunshine sensor according to claim 1, wherein the convex spherical surface of the light receiving lens is subjected to an antireflection treatment by embossing .

Images