JPH0677525A - Solar radiation sensor - Google Patents

Abstract

PURPOSE:To detect azimuth, altitude and intensity of solar light with high precision even when the altitude of solar light is low or when it is cloudy. CONSTITUTION:A solar radiation sensor 41 is constituted of a position detecting element 42, a case 43 accommodating the element 42, a lens 44 mounted on the upper surface of the case 43, etc. In the position detecting element 42, a light shielding film 46 having a light introducing hole 49 is formed on the upper surface of a glass substrate 45, and a light detecting part 47 is formed on the lower surface. As to the lens 44, a convex part 44a is formed on the upper surface side, and a concave part 44b is formed on the lower surface side. By the effect of light refraction due to the lens 44, the incident elevation of solar light into the upper surface of the position detecting element 42 becomes larger than the altitude (incident elevation of solar light into the concave part 44a), so that the reflection of the solar light on the upper surface of the position detecting element 42 is reduced, and the incident light amount into the position detecting element 42 is increased even in the case that the altitude of the solar light is low or it is cloudy.

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 having a built-in position detection element for detecting the azimuth, altitude and intensity of sunlight based on the position / amount of light of the incident light spot. It is a thing.

[0002]

2. Description of the Related Art Recently, for example, in an air conditioner for an automobile, aiming at more comfortable air conditioning, the temperature / air volume and the air blow mode (left / right air flow ratio) of the blown air are adjusted according to the direction, altitude and intensity of sunlight. A so-called solar radiation correction control for controlling has been proposed. In order to improve the accuracy of this solar radiation correction control, it is necessary to develop a solar radiation sensor that can accurately detect the azimuth, altitude and intensity of sunlight.

[0003]

Therefore, in order to detect the azimuth, altitude, and intensity of sunlight, the inventors of the present invention make the sunlight incident in a spot shape, and determine the position / light amount of the light spot by an electric signal. We are developing a solar radiation sensor with a built-in position detection element that detects automatically.

In this solar radiation sensor, a protective transparent cover is mounted on the upper surface of a case containing a position detecting element, and the sunlight transmitted through the transparent cover is guided to the upper surface side of the position detecting element. The structure is such that the light is incident in a spot shape from the hole. In order to increase the detection accuracy of the solar radiation sensor, it is necessary to increase the amount of sunlight incident on the light guide hole as much as possible (however, the light guide hole should be small).

However, the solar radiation sensor currently developed by the present inventors has good detection accuracy when the altitude of sunlight (hereinafter referred to as "solar radiation altitude") is relatively high in fine weather.
When detecting low-altitude sunlight with an insolation altitude of 15 ° or less, the amount of reflected light on the upper and lower surfaces of the transparent cover and the upper surface of the position detecting element is too large, and the amount of light reaching the light detecting portion of the position detecting element is too large. There is a drawback that the detection accuracy becomes poor because the amount is too small [see FIG. 11 (b) and FIG. 12 (b)]. In other words, the reflection of light on both the upper and lower surfaces of the transparent cover and the upper surface of the position detection element increases as the solar radiation height decreases, so that the current solar radiation sensor reaches the position detection element when the solar radiation altitude is 15 ° or less. It is difficult to accurately detect the solar radiation altitude and the like because the amount of light to be emitted is insufficient.

On a cloudy day, since the total amount of sunlight reaching the ground is small, even if the solar radiation height is relatively high, there is the amount of reflected light on the upper and lower surfaces of the transparent cover and the upper surface of the position detecting element. It cannot be ignored, and it is still difficult to accurately detect the solar radiation altitude and the like.

The present invention has been made in consideration of such circumstances, and an object thereof is to provide a solar radiation sensor capable of accurately detecting the direction, altitude and intensity of sunlight even when the solar radiation altitude is low or on a cloudy day. To provide.

[0008]

In order to achieve the above object, the solar radiation sensor of the present invention is a solar radiation sensor in which sunlight is incident in a spot shape and the direction and direction of the sunlight are determined from the position / light quantity of the light spot.
A device having a built-in position detecting element for detecting altitude and intensity is configured to suppress reflection of sunlight incident on the position detecting element (claim 1).

More specifically, an optical element for refracting incident sunlight is provided so as to increase the incident elevation angle of sunlight on the upper surface of the position detecting element (claim 2).

Alternatively, at least the position detecting element may be installed so as to be inclined so as to increase the incident elevation angle of sunlight on the upper surface of the position detecting element (claim 3).

Alternatively, a transparent filler having a refractive index close to that of both the transparent cover covering the position detecting element and the position detecting element may be filled between the position and the position detecting element (claim 4). ).

[0012]

According to the structure of claim 1, if the reflection of sunlight incident on the position detecting element is suppressed, the amount of light reaching the position detecting element is increased even when the solar radiation altitude is low or on a cloudy day. It becomes possible to accurately detect the like.

In this case, according to the second aspect, the incident sunlight is refracted by the optical element and is incident on the position detecting element, whereby the incident elevation angle of the sunlight with respect to the upper surface of the position detecting element is increased, and the position detecting element is increased. It suppresses the reflection of sunlight incident on.

Further, according to the third aspect, by tilting the position detecting element, the incident elevation angle of sunlight with respect to the upper surface of the position detecting element is increased to obtain the same light reflection suppressing effect as described above.

In general, in light of the fact that the reflection of light occurs in the process of passing through the interface of media having different refractive indexes, in claim 4, the refraction of both the transparent cover and the position detecting element is performed. A transparent filler having a refractive index close to that of the refractive index is filled to reduce the difference in the refractive index of the medium in the light incident path, thereby obtaining the same light reflection suppressing effect as described above.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS.
It will be described based on. As shown in FIG. 1, the solar radiation sensor 41 includes a position detecting element 42, a case 43 accommodating the position detecting element 42, a lens 44 as an optical element mounted on the upper surface of the case 43, and the like. The lens 44 also functions as a transparent cover that protects the position detection element 42.

The position detecting element 42 is a glass substrate 45.
The light-shielding film 46 is formed on the upper surface and the photodetector 47 is formed on the lower surface. The position detecting element 42 is molded with a light-shielding molding resin 48 except for the central portion of the upper surface (the central portion of the light shielding film 46). The light-shielding film 46 is formed to be extremely thin, for example, by printing a black epoxy resin or vapor-depositing a metal thin film, and a light guide hole 49 having a diameter of, for example, about 2 mm for introducing sunlight is formed in the center thereof. As the depth dimension of the light guide hole 49 (thickness dimension of the light-shielding film 46) becomes thinner, the rate at which sunlight entering the light guide hole 49 from obliquely above is blocked by the end surface of the light guide hole 49 decreases. It is preferable that the light-shielding film 46 has a small thickness because the amount of sunlight passing through at a low altitude increases.

On the other hand, the glass substrate 45 has, for example, a thickness of 1.
An 8 mm soda glass plate coated with SiO ₂ is used. As shown in FIG. 4, the photo-detecting section 47 formed on the lower surface of the glass substrate 45 includes an X-direction resistor film 50, a photoelectric conversion film 51, and a Y-direction resistor film 52 which are transparent in order from the light incident direction. The X-direction resistor film 50 and the Y-direction resistor film 52 are laminated, and lead electrodes X1, X2, Y1, and Y2 are provided at the respective ends.

In the first embodiment, the photoelectric conversion film 51 is
Amorphous silicon (hereinafter “a
Abbreviated as “-Si”).
i-type semiconductor film 54, p-type semiconductor film 55, i-type semiconductor film 5
Although it has a nipin layer structure in which 6 and the n-type semiconductor film 57 are laminated, a pinip layer structure may be used. In any of these cases, the photoelectric conversion film 51 has a structure in which two diode components are connected in series with their polarities opposite to each other, and a current does not flow even if a voltage of any polarity is applied to the diode components connected in series. It has become. Thereby, in the photoelectric conversion film 51, even if the temperature rises, the leakage current in the opposite direction is blocked by one diode component, and the fluctuation of the output voltage due to the temperature rise is suppressed,
Accurate position detection is possible. However, when the operating temperature of the solar radiation sensor 41 is, for example, 65 ° C. or lower, the photoelectric conversion film 5
1 may be an i-type semiconductor only.

On the other hand, the necessary function of the X-direction resistor film 50 is to transmit light and to have an appropriate sheet resistance value. For example, SnO ₂ , ZnO, ITO or the like having a thickness of about 600 angstroms. Is formed into a thin film. The sheet resistance value of the X-direction resistor film 50 may be, for example, 10 Ω / cm ² or more and 1 MΩ / cm ² or less, but is preferably 100 Ω / cm ² or more and 50 KΩ.
/ Cm ² or less. The reason for this is that if the sheet resistance value of the X-direction resistor film 50 is too low, the lead electrode X
This is because there is no difference between the resistance values of 1 and X2 and it does not make sense as a resistor. On the contrary, if the sheet resistance value of the X-direction resistor film 50 is too high, photoelectric conversion when light is irradiated is generated. Resistance value of the conversion film 51 (a-Si: about 1 KΩ to 500 K
Ω), and an appropriate output cannot be obtained.

Similarly, the sheet resistance value of the Y-direction resistor film 52 may be set to be the same as that of the X-direction resistor film 50. Therefore, the Y-direction resistor film 52 may be formed of the same material as the X-direction resistor film 50, but since the Y-direction resistor film 52 does not need to transmit light, for example, Ti, Cr, Ni or the like is used. A metal thin film, Ag paste, Ni paste, Cu paste or the like may be used. For example, when Ti is used, the thickness may be about 400 angstrom.

The position detecting element 42 configured as described above
1, is mounted on a wiring board 58 having double-sided patterns and through holes via a spacer 59, and the lead electrodes X1, X2, Y1, Y2 are soldered to the wiring board 58. An end of a lead wire 61 is pressure-bonded and fixed to a connection terminal 60 soldered to the wiring board 58, and a detection signal is taken out through the lead wire 61.

On the other hand, the lens 44 mounted on the upper surface of the case 43 by adhesion or the like is made of, for example, polycarbonate resin,
It is made of a transparent resin such as acrylic resin, a convex surface portion 44a is formed on the upper surface side, and a concave surface portion 44b is formed on the lower surface side. Both the convex surface portion 44a and the concave surface portion 44b are mirror-finished. However, only the convex surface portion 44a may be finely roughened on the surface without being mirror-finished so as to improve the appearance in design. The dimensions of each part of the lens 44 are shown in FIG. This lens 4
When the sunlight enters the light source 4, the sunlight is refracted by the convex surface portion 44a and the concave surface portion 44b and guided to the position detecting element 42 as shown in FIG. Therefore, the convex portion 44
When the incident elevation angle (altitude) of sunlight with respect to a is θ o and the incident elevation angle of sunlight with respect to the upper surface of the position detecting element 42 is θ 1, the relationship between θ o and θ 1 is shown in FIG. 7 due to the photorefractive action of the lens 44. Thus, in the case of the dimension setting shown in FIG. 6, θ1 = 2/3 × θo + 30. The lens 44 has an infinite focal length, and is designed so that the light flux of sunlight toward the light guide hole 49 is refracted in parallel.

As shown in FIG. 1, positioning boss portions 71 are integrally formed downward at a plurality of positions on the outer peripheral surface of the lower surface of the lens 44, and small protrusions formed at the lower end of the positioning boss portion 71. 72 is fitted in a positioning hole 73 formed in the mold resin 48 of the position detection element 42. Accordingly, the lens 44 for the position detecting element 42
Are positioned in the horizontal and vertical directions.

The solar radiation sensor 41 constructed as described above
Is horizontally attached to the upper surface of a dashboard 63 of an automobile 62, for example, as shown in FIG. As shown in FIG. 9, in this automobile 62, in addition to the solar radiation sensor 41,
An outside air temperature sensor 64, an indoor air temperature sensor 65, an after air temperature sensor 66 for detecting a rear temperature of a cooler (not shown), a water temperature sensor 67 for detecting a temperature of engine cooling water, and various operation switches (not shown). An operation panel 68 and the like provided with are provided, and the data input from these are processed by the control circuit 69 to control the temperature / air volume of the air blown from the air conditioner 70 and the blowout mode (left / right airflow ratio). Has become.

The control circuit 69 detects the azimuth, altitude and intensity of sunlight on the basis of the signal output from the solar radiation sensor 41 as follows. Here, the three-dimensional coordinates that are the basis of the azimuth and altitude of sunlight are, as shown in FIG. 13, the horizontal right direction is the X-axis direction, the horizontal rear direction is the Y-axis direction, and the vertically upper direction is the Z-axis direction. The position of the light spot on 51 is P (x, y).

(A) Method for detecting X coordinate of light spot P (x, y) As shown in the left column of FIG. 5, 5V and 0V are applied to the lead electrodes X1 and X2 on both ends of the X-direction resistor film 50, respectively. Y
A voltage (hereinafter referred to as "X coordinate voltage") Vx corresponding to the X coordinate of the light spot P (x, y) is obtained from one or both of the lead electrodes Y1 and Y2 on both ends of the directional resistor film 52. At this time, the current flows from the X-direction resistor film 50 side to the Y-direction resistor film 52 side at the light spot irradiation position in the photoelectric conversion film 51.

As a circuit (for example, a digital multimeter) for detecting the X coordinate voltage Vx, it is desirable that the input impedance is 1 MΩ or more, that is, the voltage value can be detected with almost no current flowing. This is because if this input impedance is small, the voltage drop due to the existing resistance of the Y-direction resistor film 52 cannot be ignored, and the X coordinate voltage Vx drops.

Here, the X coordinate voltage obtained from the center point O of the photoelectric conversion film 51 located directly below the light guide hole 49 is Vox,
The electric potential gradient [V / mm] of the photoelectric conversion film 51 in the X-axis direction is ΔV
If x is set, the light spot P (x, y) is converted from the X-coordinate voltage Vx detected corresponding to the X coordinate of the light spot P (x, y).
The X coordinate of y) is expressed as follows.

X = (Vx-Vox) / ΔVx

(B) Method for detecting Y coordinate of light spot P (x, y) As shown in the middle column of FIG. 5, 5V and 0V are applied to the lead electrodes Y1 and Y2 on both ends of the Y-direction resistor film 52, respectively. X
A voltage (hereinafter referred to as “Y coordinate voltage”) Vy corresponding to the Y coordinate of the light spot P (x, y) is obtained from one or both of the lead electrodes X1 and X2 at both ends of the directional resistor film 50. At this time, the direction of the flowing current is opposite to the above-mentioned case, and the X-direction resistor film 5 is moved from the Y-direction resistor film 52 side.
It flows to the 0 side. Other than this, it is the same as the X coordinate detection described above.

Here, the Y coordinate voltage obtained from the center point O of the photoelectric conversion film 51 located directly below the light guide hole 49 is Voy,
The potential gradient [V / mm] of the photoelectric conversion film 51 in the Y-axis direction is ΔV
Let y be the light spot P (x, y) from the Y coordinate voltage Vy detected corresponding to the Y coordinate of the light spot P (x, y).
The Y coordinate of y) is represented as follows.

Y = (Vy-Voy) / ΔVy

(C) Method of detecting solar radiation intensity (photocurrent) As shown in the right column of FIG. 5, 5V is applied to both lead electrodes Y1 and Y2 on both ends of the Y-direction resistor film 52 to apply the Y-direction resistor. The entire area of the membrane 52 is kept at the same potential. In this state, the photocurrent (current flowing from the Y-direction resistor film 52 side to the X-direction resistor film 50 side) generated at the position where the light spot is irradiated is detected. This photocurrent does not change wherever the light spot is irradiated (because the entire region of the Y-direction resistor film 52 has the same potential), and becomes a signal that changes according to the solar radiation intensity (incident light amount).

Contrary to the above, the X-direction resistor film 50 is formed.
Apply 5V to the lead electrodes X1 and X2 on both ends of
It goes without saying that the photocurrent flowing from the direction resistor film 50 side to the Y direction resistor film 52 side may be detected.

Here, when the photocurrent generated in the light spot P (x, y) is J, the solar radiation intensity is I, and the incident elevation angle (altitude) of sunlight obtained as described later is θo.
Since the photocurrent A is J = I × sin θo, the solar radiation intensity I is obtained by the following equation (1).

I = J / sin θo (1) However, in reality, since it is affected by the reflection of light generated on the surface of the lens 44 and the glass substrate 45, the following (1) is given by the following equation (2). ) Is approximated to obtain the insolation intensity I.

[0038]

[Equation 1] In this equation (2), a, b, c, d, e and f are constants.

(D) Method of Detecting Sunlight Direction φ As shown in FIG.
Assuming the angle between (x, y) and the Y-axis, the azimuth φ of sunlight is calculated as follows from the coordinates of the light spot P (x, y) calculated as described above.

[0040]

[Equation 2]

(E) Method of detecting altitude θo of sunlight Since sunlight passes through the lens 44 and enters the glass substrate 45 of the position detecting element 42, the sunlight is convex on the lens 44 as shown in FIG. The light is refracted by the portion 44a and the concave portion 44b and is guided to the glass substrate 45 of the position detecting element 42. Therefore, the incident elevation angle (altitude) of sunlight on the convex surface portion 44a of the lens 44 is θo, and the position detection element 42
The incident elevation angle of sunlight on the upper surface of the glass substrate 45 of
If set to 1, θo and θ1
As shown in FIG. 7, the relationship between and is expressed by a linear function, and in the case of the dimension setting shown in FIG. 6, θ1 = 2/3 × θo + 30 (4). The formula for obtaining the altitude θo of the sunlight from the formula (4) is as the following formula (5).

Θo = 3/2 × θ1 −45 (5) Further, the angle of incident light refracted by the glass substrate 45 of the position detecting element 42 is θ2, and the refractive index of the glass substrate 45 is n.
Then, assuming that the refractive index of air is 1, the relationship between the incident elevation angle θ1 to the glass substrate 45 and the angle θ2 of the incident light refracted by the glass substrate 45 is expressed by the following equation (6).

Sin (π / 2−θ1) / sin (π / 2−θ2) = n (6) Then, assuming that the thickness dimension of the glass substrate 45 is t, the incident elevation angle θ1 to the glass substrate 45 is It is calculated from the following equation (7).

[0044]

[Equation 3] In the equation (7), α is a correction coefficient that takes into account the deviation of the center position of the light spot depending on the depth of the light guide hole 49 (thickness of the light shielding film 46). By substituting θ1 calculated by the equation (7) into the equation (5), the altitude θo of the sunlight can be obtained. When the influence of the depth of the light guide hole 49 can be ignored, α = 0, and A is expressed as follows using the equation (6).

[0045]

[Equation 4]

Next, the flow of air conditioning control by the control circuit 69 will be described with reference to the flowchart of FIG. First, various data are initialized (step 201), and the data input from the solar radiation sensor 41 or other sensors 64 to 67 and the operation panel 68 are read (step 202). After this,
Calculate the altitude θo and direction φ of the sunlight (step 20)
3). Here, the altitude θo of the sunlight is calculated using the equations (7) and (5) described above, and the azimuth φ is the equation (3) described above.
Calculate using a formula. Next, the solar radiation intensity I is calculated using the above-mentioned equation (2) (step 204).

After that, the correction coefficient K corresponding to the altitude θo of the sunlight is obtained from the data stored in the ROM (not shown), and the correction coefficient K is multiplied by the solar radiation intensity I to obtain the sun. A solar heat load amount Qs corrected according to the light altitude θo is calculated (step 205). Next, the amount of heat required for air conditioning in the passenger compartment (target blowout temperature TAO) is calculated by the following equation using the above-mentioned amount of solar heat load Qs (step 206).

TAO = Kset.Tset-Kr.Tr-Kam.Tam-Ks.Qs + C where Kset, Kr, Kam.Ks and C are constants and Tset
Is a set temperature manually set by a temperature setting switch (not shown) on the operation panel 68, and Tr is the indoor temperature sensor 65.
The room temperature Tam detected by Tam is the outside air temperature detected by the outside air temperature sensor 64.

The target outlet air temperature TAO thus obtained,
Based on the post-evaporator temperature detected by the post-evaporator temperature sensor 66, the blown air volume and the blown-out temperature are calculated (step 207),
Further, based on the altitude θo of the sunlight and the azimuth φ calculated in step 203, the ratio of the air volume blown out from the left and right vent outlets (not shown) is calculated (step 208). After that, the above-described steps 202 to 208 are repeatedly executed, and the air conditioner 70 is controlled according to the calculated blown air volume, blown air temperature, and left / right air volume ratio each time.

According to the first embodiment described above, the sunlight incident on the solar radiation sensor 41 is refracted by the lens 44. Therefore, even if the altitude θo of the sunlight is low, the upper surface of the position detecting element 42 is prevented. The incident elevation angle θ1 of the sunlight with respect to can be increased, and the reflection of the sunlight incident on the position detection element 42 can be suppressed. As a result, even when the altitude θo of sunlight is low or on a cloudy day, the position detection element 4
It is possible to secure a large amount of light incident on the light source 2, and it is possible to accurately detect the azimuth, altitude, and intensity of sunlight.

The present inventors conducted a test for comparing the performance with the lens-unmounted product in order to evaluate the detection performance of the lens-mounted product as in the first embodiment. The test results are shown in FIG.
And shown in FIG. In each of these figures, (a) shows a test result of a lens-mounted product, and (b) shows a test result of a lens-unmounted product. As is clear from these test results, in the lens-unmounted product (b), the altitude of sunlight is 15 ° or less, which makes it difficult to detect the insolation intensity and significantly deteriorates the accuracy of altitude detection. It has been confirmed that in the lens-mounted product (a) as in the first embodiment, both the solar radiation intensity and the altitude can be accurately detected even when the altitude of sunlight is 15 ° or less.

The lens 44 used in the first embodiment described above.
Has an infinite focal length and is designed so that the light flux of the sunlight toward the light guide hole 49 is refracted in parallel. However, as in the second embodiment of the present invention shown in FIG. Alternatively, the lens 75 having a finite focal length in which the light flux of sunlight is not refracted in parallel may be used as an optical element. In this case, only the sun rays passing through the center of the light guide hole 49 are correctly converted, and the sun rays passing through the periphery of the light guide hole 49 deviate from the ideal values, but the diameter of the light guide hole 49 can be reduced. If so, the detection error is at a level that can be ignored.

Further, the shape of the lens (optical element) mounted on the upper surface of the solar radiation sensor is not limited to the above-mentioned respective embodiments, and for example, the lens 76 as in the third embodiment of the present invention shown in FIGS. May be formed. The lens 76 has a tapered surface portion 76b having a flat portion 76a on the upper surface side and a concave surface portion 76d having a flat portion 76c on the lower surface side. The dimensions of each part of the lens 76 are shown in FIG. When the incident elevation angle (altitude) of the sunlight on the lens 76 is θo and the incident elevation angle of the sunlight on the upper surface of the position detecting element 42 is θ1, the relationship between θo and θ1 is shown in FIG. In the case of the dimension setting shown in FIG. 16 and shown in FIG.

When 0 ≦ θo <50 °, θ1 = θo / 2 + 25 When 50 ° ≦ θo ≦ 90 °, θ1 = θo

In the third embodiment, the center of the lens 76, through which sunlight at an altitude of 50 ° or higher is transmitted, has a flat portion 76a,
Since it is 76c, the high altitude sunlight passing through the flat portions 76a and 76c is not unnecessarily refracted, which facilitates the arithmetic processing and avoids an unnecessary lens action. is there.

On the other hand, in the first embodiment described above, the lens 4
By fitting the small projection 72 at the lower end of the positioning boss portion 71 formed on the lower surface side of 4 into the positioning hole 73 formed in the mold resin 48 of the position detecting element 42, Since the lens 44 is positioned in the horizontal direction and the vertical direction, there is an advantage that the assembly accuracy can be improved. The positioning structure of the lens 44 can be modified in various ways. For example, the fourth structure of the present invention shown in FIG.
As in the embodiment, the small projection 72 at the lower end of the positioning boss portion 71 formed on the lower surface side of the lens 44 is fitted into the positioning hole 77 of the wiring board 58 on which the position detection element 42 is mounted. Is also good. Of course, it goes without saying that a positioning structure other than this may be adopted.

The first to fourth embodiments described above are
It is an embodiment embodying the invention of claim 2 described in the claims.

On the other hand, the fifth embodiment of the present invention shown in FIGS. 19 to 23 embodies the invention of claim 3. The solar radiation sensor 81 of the fifth embodiment is also the same as the first embodiment described above.
Similar to the embodiment (see FIG. 8), for example, the solar sensor 41 is mounted on the upper surface of the dashboard 63 of the automobile 62. The position detecting element 42 is installed so as to be inclined so as to face obliquely upward in the traveling direction of the automobile 62. The tilt angle α of the position detecting element 42 may be 30 ° or less, but is preferably about 10 °.

The solar radiation sensor 81 has the same structure as the solar radiation sensor 41 of the first embodiment described above, except that the solar radiation sensor 81 is inclined and the transparent cover 82 is mounted on the upper surface. The transparent cover 82 is formed in a slightly convex lens shape in order to improve the transparency of low altitude sunlight, but it goes without saying that it may be a simple flat plate shape or a curved surface shape.

Next, a method for obtaining the altitude θ, azimuth φ and intensity I of sunlight using this solar radiation sensor 81 will be described.

In the coordinate setting shown in FIG. 21 (when the light guide hole 49 is the origin and the XY coordinate axes are horizontal), the incident direction of sunlight is (-cos θcos φ, −cos θsin φ, −
sin θ). Here, the X-axis direction is the traveling direction of the automobile 62, the Y-axis direction is the horizontal left direction when viewed from the driver's seat side, and the Z-axis direction is Z.
The axial direction is set vertically above.

The coordinate system of FIG. 21 is rotated by an angle α around the Y axis.
When tilted only (see FIG. 22), the incident direction (X, Y, Z) of sunlight is expressed by the following equation in the new coordinate system.

[0063]

[Equation 5] Here, if the refraction direction of the incident light is (X ', Y', Z '),

[Equation 6] Further, assuming that the refractive index of the glass substrate 45 is n, from the law of refraction,

[Equation 7] Therefore, from these equations and the equation (8), the refraction direction (X
′, Y ′, Z ′) is calculated by the following equation.

[0064]

[Equation 8] Furthermore, z = t (t is the thickness of the glass substrate 45), x / X '
= Y / Y '= z / Z', the light spot P (x,
The coordinates of y) are calculated by the following equation.

[0065]

[Equation 9] Therefore, the altitude θ and the azimuth φ of sunlight are calculated by the following equations.

[0066]

[Equation 10] On the other hand, the solar radiation intensity I is calculated by the following equation.

[0067]

[Equation 11] Here, A (θ) is the output current. Also, f (θ,
φ) is the inner product of the incident direction (X, Y, Z) and the normal vector (0, 0, −1) of the position detection element 42, and f (θ, φ) = (X, Y, Z)・ (0,0, -1) = sin θcos α + sin αcos θcos φ

In the fifth embodiment described above, the position detecting element 42 is tilted by the angle α, so that the lenses 44, 75 and 76 shown in the first to fourth embodiments are not used. The same light reflection suppressing effect as can be obtained.

By the way, when the position detecting element 42 is installed horizontally as in the comparative example shown in FIG. 20B, if the altitude θ of sunlight is low, the amount of reflected light on the upper surface of the glass substrate 45 is too large. As a result, the amount of light of the light spot P reaching the photoelectric conversion film 51 decreases. For this reason, the photocurrent A ′ generated at the position of the light spot P becomes small, and this photocurrent A ′ is generated directly below the light guide hole 49 due to scattered light from the sky (sky radiation). It approaches ´.
Normally, the position detecting element 42 detects the position of the center of gravity of the photocurrents A ′ and B ′ as the light spot position. Therefore, when A ′ approaches B ′, the detected light spot position is P, as described above. There is a drawback that the altitude θ of the sunlight is detected to be considerably higher than the actual value because it is largely shifted from P to P ′ (see x mark in FIG. 23).

In this regard, in the fifth embodiment, as shown in FIG. 20 (a), the position detecting element 42 is tilted by the angle α, so that it is higher than the actual insolation altitude θ by the angle α. Since the sunlight is incident on the position detecting element 42 at an angle, the amount of reflected light on the upper surface of the position detecting element 42 is reduced accordingly, and the amount of incident light spot is reduced by the inclination angle α.
Increase by minutes. For this reason, the photocurrent A due to the light spot of the incident sunlight becomes sufficiently larger than the photocurrent B due to the scattered light (sky radiation) from the sky, and for example, the scattered light (sky radiation) is low even at a low altitude of 15 ° or less. ), It is possible to detect the altitude, direction and intensity of sunlight with high accuracy.

Incidentally, according to the performance comparison test conducted by the present inventors (see FIG. 23), when the position detecting element 42 is installed horizontally (inclination angle α = 0 °), the mark x in FIG. The detection accuracy is significantly reduced at 15 ° or less, as shown in FIG. 4, whereas when the position detection element 42 is tilted as in the fifth embodiment, the sunlight is indicated by black squares in FIG. It has been confirmed that the detection accuracy can be maintained well even when the altitude of 15 ° or less.

Although the solar radiation sensor 41 is tilted in the fifth embodiment, only the position detecting element 42 is tilted without tilting the case 43 or the transparent cover 82, or the position detecting element is tilted. It is also possible to incline only 42 and the wiring board 58 and the like associated therewith, and even in this case, substantially the same effect can be obtained.

On the other hand, the sixth embodiment of the present invention shown in FIGS. 24 to 26 embodies the invention of claim 4. In the sixth embodiment, attention is paid to the fact that a large amount of light reflection occurs at the interface of media having a large difference in refractive index.
5, a transparent filler 86 having a refractive index close to that of the transparent cover 86 and the glass substrate 45 is filled between the transparent cover 86 mounted on the upper surface of the case 43 and the glass substrate 45 of the position detection element 42. There is. In this case, the transparent cover 86 is
For example, the glass substrate 45 is formed of a transparent resin having a refractive index of 1.4 to 1.6, and the glass substrate 45 has a refractive index of about 1.5. Therefore, the transparent filler 87 has, for example, a refractive index of 1.43.
A transparent silicone resin of ˜1.48 [KE109 (A, B) manufactured by Shin-Etsu Chemical Co., Ltd.] is used. The transparent silicone resin is in a solidified state after, for example, 1 hour at 100 ° C. after filling.

The solar radiation sensor 85 of the sixth embodiment is, for example, an automobile 6 as in the first embodiment (see FIG. 8) described above.
It is horizontally attached to the upper surface of the second dashboard 63. The configuration other than this is the same as that of the first embodiment described above.

By the way, as in the comparative example shown in FIG.
If there is an air layer (refractive index = 1) between the transparent cover 86 and the glass substrate 45 of the position detection element 42, the transparent cover 86
Reflection of light is likely to occur at the interface between the air layer and the air layer and the interface between the air layer and the glass substrate 45. The greater the difference in refractive index, the greater the amount of light reflected, and the poorer the light transmittance. In particular, the amount of light reflected when refracting from a medium with a large refractive index (transparent cover 86) to a medium with a small refractive index (air layer) is the largest.

Therefore, in the sixth embodiment, a transparent filler 87 having a refractive index close to that of the transparent cover 86 and the glass substrate 45 is filled between the transparent cover 86 and the glass substrate 45 of the position detecting element 42. By doing so, the difference in the refractive index between these three is reduced. Therefore, the reflection of light at the interface between the three is suppressed, the light transmittance is increased, and the light amount of the light spot reaching the photoelectric conversion film 51 is increased.

Incidentally, according to the calculation result of the light transmittance by the present inventors, as shown in FIG.
Has a refractive index of 1.45, and the transparent filler 87 has a refractive index of 1.4.
8. When the refractive index of the glass substrate 45 is 1.52, a sufficiently large light transmittance can be secured even at a low altitude of 15 ° or less, and the light quantity of the light spot reaching the photoelectric conversion film 51 can be sufficiently increased. . Therefore, the photocurrent A due to the light spot of the incident sunlight is sufficiently larger than the photocurrent B due to the scattered light (sky radiation) from the sky, and the scattered light (sky radiation) is generated even at a low altitude of 15 ° or less, for example. It is possible to detect the altitude, azimuth and intensity of sunlight with high accuracy without being significantly affected by.

In this case, as shown in FIG. 26, the altitude of sunlight is θo, and the incident elevation angles of light refracted sequentially by the transparent cover 86 → transparent filler 87 → glass substrate 45 are θ1, θ2, θ3, respectively. Assuming that the refractive index of the transparent cover 86 is n1, the refractive index of the transparent filling material 87 is n2, and the refractive index of the glass substrate 45 is n3, the following formulas are established.

[0079]

[Equation 12] By solving these mathematical expressions, the altitude θo of the sunlight can be obtained.

The transparent filler 87 may be any solid (eg, epoxy resin, acrylic resin, etc.), liquid, semi-fluid, or elastic body as long as it is a transparent material. Is used, there is an advantage that the sealing structure of the transparent filler 87 can be simplified. Further, the shape of the transparent cover 86 can be variously changed, and may be formed in a slightly convex lens shape as in the fifth embodiment described above, or may be formed in a simple flat plate shape.

Further, each of the first to sixth embodiments may be appropriately combined and implemented. For example, the transparent filler may be filled between the lens (transparent cover) and the position detecting element in any of the embodiments other than the sixth embodiment, and the positions of the embodiments other than the fifth embodiment may be changed. You may make it install a detection element inclining.

In addition, the solar radiation sensor of the present invention is not limited to the one used in the air conditioner for automobiles, and can be used in various places.
It can be widely modified as a solar radiation sensor for detecting the altitude, direction, and intensity of sunlight, and various modifications can be made.

[0083]

As is apparent from the above description, according to the present invention, an optical element is provided above the position detecting element,
By tilting the position detection element or filling a transparent filler between the position detection element and the transparent cover, it is possible to suppress reflection of sunlight incident on the position detection element. Therefore, it is possible to increase the amount of sunlight that is generated, and it is possible to accurately detect the altitude, direction, and intensity of sunlight even when the altitude of sunlight is low or on a cloudy day.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a solar radiation sensor showing a first embodiment of the present invention.

FIG. 2 is a perspective view of the position detection element when viewed from diagonally above.

FIG. 3 is a perspective view of the position detection element shown with a mold resin removed, as viewed from obliquely below.

FIG. 4 is a vertical sectional view schematically showing the structure of a position detection element.

FIG. 5 is a diagram for explaining a method of detecting an X coordinate, a Y coordinate, and a photocurrent.

FIG. 6 is a diagram showing dimensions of each part of the lens.

FIG. 7 is a diagram showing the relationship between the altitude θo of sunlight and the incident elevation angle θ1 of the position detection element.

FIG. 8 is a perspective view of the automobile showing the installation location of the solar radiation sensor.

FIG. 9 is a block diagram showing an electrical configuration.

FIG. 10 is a flowchart showing the flow of control.

FIG. 11 is a lens-mounted product (a) and a lens-unmounted product (b).
About the set altitude and detected insolation intensity

[FIG. 12] Lens-equipped product (a) and lens-unequipped product (b)
About the relationship between the set altitude and the detected altitude

FIG. 13 is an explanatory diagram for calculating the altitude and direction of sunlight.

FIG. 14 is a vertical cross-sectional view of a main part showing a second embodiment of the present invention.

FIG. 15 is a vertical cross-sectional view of a main part showing a third embodiment of the present invention.

FIG. 16 is a diagram showing the dimensions of each part of the lens.

FIG. 17 is a diagram showing the relationship between the altitude θo of sunlight and the incident elevation angle θ1 of the position detection element.

FIG. 18 is a vertical cross-sectional view of a main part showing a fourth embodiment of the present invention.

FIG. 19 is a vertical sectional view of a solar radiation sensor showing a fifth embodiment of the present invention.

FIG. 20 is a view for explaining the action and effect by comparing the case where the position detecting element is tilted (a) and the case where the position detecting element is installed horizontally (b).

FIG. 21 is a diagram illustrating how to take a reference coordinate axis (tilt angle α = 0 °).

FIG. 22 is a diagram for explaining coordinate conversion when the coordinate axis is tilted according to the tilt angle α of the position detection element.

FIG. 23 is a diagram showing the results of a performance comparison test on the detected altitude.

FIG. 24 is a vertical cross-sectional view of the essential parts showing the sixth embodiment of the present invention.

FIG. 25 is a diagram showing the relationship between altitude and light transmittance when a transparent filler is used.

FIG. 26 is a diagram illustrating a refraction angle of incident light.

FIG. 27 is a diagram illustrating a defect of the comparative example.

[Explanation of symbols]

41 is a solar radiation sensor, 42 is a position detection element, 43 is a case, 44 is a lens (optical element), 45 is a glass substrate, 4
6 is a light-shielding film, 47 is a light detecting portion, 48 is a molding resin, 4
9 is a light guide hole, 50 is an X-direction resistor film, 51 is a photoelectric conversion film, 52 is a Y-direction resistor film, 53 is an n-type semiconductor film, 54
Is an i-type semiconductor film, 55 is a p-type semiconductor film, 56 is an i-type semiconductor film, 57 is an n-type semiconductor film, 75 and 76 are lenses (optical elements), 81 is a solar sensor, 82 is a transparent cover, 85
Is a solar radiation sensor, 86 is a transparent cover, and 87 is a transparent filler.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yutaka Maeda, 1-1, Showa-cho, Kariya city, Aichi Prefecture, Nihon Denso Co., Ltd. (72) Inventor, Tomoji Terada, 1-1, Showa-cho, Kariya city, Aichi prefecture Within the corporation

Claims (4)

[Claims] 1. A solar radiation sensor having a built-in position detecting element for detecting the azimuth, the altitude and the intensity of sunlight from the position / light quantity of the light spot by injecting sunlight in a spot shape, to the position detecting element. A solar radiation sensor, which is configured to suppress reflection of incident sunlight. 2. The solar radiation sensor according to claim 1, further comprising an optical element that refracts incident sunlight so as to increase an incident elevation angle of sunlight on the upper surface of the position detection element. 3. The solar radiation sensor according to claim 1, wherein at least the position detecting element is installed so as to be inclined so as to increase an incident elevation angle of sunlight on the upper surface of the position detecting element. 4. A transparent cover is provided to cover the position detecting element from above, and a transparent filler having a refractive index close to that of the transparent cover and the position detecting element is filled between the transparent cover and the position detecting element. The solar radiation sensor according to claim 1.