JP3412215B2 - Optical position detector - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light position detecting device capable of detecting the incident direction of light and its intensity, and more particularly to controlling the temperature, blown amount, blown direction, etc. of conditioned air in an air conditioner for automobiles. The present invention relates to an optical position detection device suitable for

[0002]

2. Description of the Related Art Conventionally, in an air conditioner for an automobile, in order to optimally control the temperature, the amount of air blown, the direction of the conditioned air, etc. according to the intensity of the solar radiation and the direction of the solar radiation, An optical position detecting device capable of detecting

As such an optical position detecting device, for example,
As disclosed in JP-A-56-64611,
2. Description of the Related Art There is known a sun angle measuring device including a light-shielding plate having a pinhole formed therein and a two-dimensional light-receiving sensor arranged so as to face the light-shielding plate. In such an apparatus, a plurality of light receiving elements are two-dimensionally arranged, and the light irradiation position is detected by checking which light receiving element receives the light transmitted through the pinhole. It is necessary to provide an analog switch or the like for selectively outputting an output from each light receiving element in the detection circuit of the light receiving element.

As a detection circuit of this type, for example, as shown in FIG. 10, n photodiodes D1 to Dn forming a light receiving sensor are respectively provided with capacitors C1.
.About.Cn are connected in parallel and the capacitors C1 to C are connected.
By providing CMOS type transistors TR1 to TRn for taking out the terminal voltage of n to the outside and CMOS type transistor TR0 for charging the capacitors C1 to Cn for each pixel, each pixel of the light receiving sensor Detection circuits K1 to Kn are formed in each of the detection circuits K1 to Kn, and each of the detection circuits K1 to Kn is sequentially turned on to charge the capacitors C1 to Cn with the reference voltage V1. It is known that the amount of electric charge discharged through Dn is detected by turning on a transistor TRi (i = 1 to n), and this is output as a detection signal representing the amount of light received by each photodiode D1 to Dn. ing.

[0005]

However, in the detection circuit configured as described above, the photodiodes D1 to Dn which are light receiving elements and the detection circuits K1 to Kn for detecting the signals of the photodiodes D1 to Dn are provided. Since the constituent elements are adjacent to each other, the light emitted to the photodiodes D1 to Dn is also emitted to the transistors TR1 to TRn which are analog switches. The characteristics of the element formed of a semiconductor such as a transistor change when irradiated with strong light, and as a result, the detection circuits K1 to K1.
Since the output voltage and the like output from n fluctuates, there is a problem that accurate detection cannot be performed.

In order to avoid this, it may be possible to install an analog switch or the like away from the light receiving element at a position where light is not emitted. However, the wiring from each light receiving element becomes enormous, so that the device scale is small. There was a problem that I could not do it. Further, since the signal detected here is very small, there is a problem that if the wiring is too long, accurate detection cannot be performed due to the influence of the wiring capacitance and the like.

In order to solve such problems, it is an object of the present invention to provide an optical position detecting device which can always perform accurate detection regardless of the light irradiation state.

[0008]

The optical position detecting device of the present invention, which has been made to achieve the above object, faces a light shielding plate having a light introduction port and a predetermined distance to the light shielding plate. A light-transmitting portion in which pixels of a liquid crystal element that are arranged and that transmit / block light according to an applied electric field are two-dimensionally arranged;
A transmission control unit that sequentially drives the pixels of the liquid crystal element so that any one of the pixels of the liquid crystal element arranged in the light transmission unit transmits the light, and a light receiving unit that receives the light transmitted through the light transmission unit. And an output signal from the above-mentioned light receiving element
The received light intensity of the light radiated to the light receiving element section detected from
Degree, and the light irradiation position on the transmission part,
It is characterized by detecting the intensity and incident direction of the emitted light .

[0009]

In the optical position detecting device of the present invention configured as described above, the light transmitted through the introduction port formed in the light shielding plate is transmitted to the light transmitting portion in which the pixels of the liquid crystal element are two-dimensionally arranged. Is irradiated. The transmission controller sequentially drives the pixels of the liquid crystal element so that any one of the pixels of the liquid crystal element transmits light. Then, when the pixel illuminated with light is driven, the light passes through the light transmitting portion and is received by the light receiving element portion. Then, it is detected from the output signal of the light receiving element section.
Intensity of the light radiated to the light receiving element part
Based on the light irradiation position at
Detects the shooting direction. The incident direction of light and its intensity can be known by examining the intensity of light received when the element portion is irradiated with light and the pixel of the liquid crystal element that is being driven at that time.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 2, the optical position detecting device 1 of the present embodiment is
It is attached to the front position in the passenger compartment 3 of the automobile,
It is a so-called solar radiation sensor for detecting the intensity I and direction of insolation that intrudes into the interior (the left and right incident angle φ of solar radiation with respect to the straight-ahead direction of the vehicle and the elevation angle θ representing the solar radiation altitude), and in an automobile air-conditioning system, It is used to control the temperature of conditioned air, the amount of air blown, the direction of air blow, and so on.

As shown in FIG. 3, the optical position detecting device 1 includes a detecting element section 10, a clip terminal 12 serving as an electrode of the detecting element section 10, and the detecting element section 10 via the clip terminal 12.
And a printed circuit board 16 for electrically connecting a microcomputer 30 for air conditioning control described later and the detection element unit 10 by connecting the external connector 14 from the air conditioner and the clip terminal 12 with each other. 1
The tubular casing 18 that grips 6 to project the detection element portion 10 from the opening, and the detection element portion 10 is fitted and fixed to the opening edge of the tubular casing 18 to cover the detection element portion 10 and And a light-transmitting filter 20 for protection.

Here, as shown in FIG. 1A, the detection element portion 10 has a glass substrate 22 having a refractive index of 1.5 and a light shielding film 24 as a light shielding plate formed on the surface of the glass substrate 22. And the light receiving portion 26 fixed to the back surface of the glass substrate 22.
It consists of and. In addition, the light-shielding film 24 is shown in FIG.
As shown in (b), a pinhole 24a is formed on the surface of the glass substrate 22, and the portion other than the pinhole 24a is for shielding sunlight, and is formed by printing or the like.

On the other hand, in the light receiving section 26, as shown in FIG. 1B, the liquid crystal panel 2 in which pixels are arranged in a matrix.
5, and a liquid crystal driver circuit 27 that drives the liquid crystal panel 25 so that each pixel of the liquid crystal panel 25 sequentially transmits light.
A photodiode D (see FIG. 1) which is provided below the liquid crystal panel 25 and receives the light transmitted through the pixels of the liquid crystal panel 25.
(See (a)), and a signal processing circuit 28 for sequentially extracting light reception signals from the photodiode D.

The light receiving section 26 has the electrode pattern of the signal processing circuit 28 formed on the chip and the glass substrate 2.
The electrode pattern formed in 2 is fixed to the glass substrate 22 by soldering as shown by H in FIG. 1A, and the surface of the light receiving portion 26 other than the soldered portion is covered by the glass substrate 22. It is protected by a silicone gel 29 having a refractive index of 1.4 provided between and.

Next, the liquid crystal panel 25 is one in which an antiferroelectric liquid crystal is sealed between two electrode substrates each having a transparent glass plate coated with electrodes, and one of the electrode substrates has:
m row electrodes are formed in parallel, and the other electrode substrate is
It is a well-known one in which n rows of column electrodes are formed so as to be orthogonal to the respective row electrodes, and m × n pixels are formed in a matrix by the respective row electrodes and column electrodes.

The liquid crystal panel 25 blocks light unless a voltage is applied between the electrodes, and when a voltage is applied between the electrodes, light is emitted only to the pixels sandwiched between the electrodes to which the voltage is applied. It is configured as a transparent light shutter. In the optical position detecting device 1 of the present embodiment configured in this way, as shown in FIG. 4, when sunlight A is incident, a part of the sunlight A passes through the pinhole 24a, and the pinhole 24a The light becomes B, and a part of the pixels of the liquid crystal panel 25 is irradiated according to the direction of solar radiation (that is, the incident angle φ and the elevation angle θ of sunlight).

On the other hand, each pixel of the liquid crystal panel 25 is driven so as to sequentially transmit light at a predetermined timing,
When the pixel irradiated with the pinhole light B is driven,
The pinhole light B passes through the liquid crystal panel 25 and is received by the light receiving section 26.
The light is received by the upper photodiode D, and the photodiode D sequentially outputs detection signals corresponding to the amount of received light in each pixel.

Since the pixels of the liquid crystal panel 25 are smaller than the diameter of the pinhole 24a, a plurality of pixels are irradiated at the same time, and the central pixel G (Xi, Yj) is the pinhole light B
It represents the center of. Therefore, the photodiode D
If the center pixel G (Xi, Yj) of the pixels of the liquid crystal panel 25 which is being irradiated with the pinhole light B is detected based on the output signal of the above, the center position P1 of the pinhole light B on the liquid crystal panel 25 is determined. It can be detected and this center position P1
It becomes possible to detect the incident angle φ and the elevation angle θ of the sunlight based on the deviation from the reference position P0 when the sunlight A is incident from directly above the light position detection device 1.

In the liquid crystal panel 25, the incident light from the pinhole 24a is refracted by the glass substrate 22 when the sun is at a low altitude so that the center position P1 of the pinhole light can always be detected. The one that is large enough to cover all the irradiated positions is used.

Next, the light receiving section 26 fixed to the glass substrate 22 is, via the glass substrate 22, the clip terminal 12, the printed board 16 and the external connector 14, a microcomputer for controlling the air conditioner as shown in FIG. Connected to 30. With this connection, the liquid crystal driver circuit 2
7 and the signal processing circuit 28 are the microcomputer 3
0 power supply (VDD) terminal and ground (GND) terminal connected to the microcomputer 30 power supply (VDD)
The reset signal (RST) and the clock signal (C) output from the microcomputer 30 while being supplied.
LK) to operate and output the detection signal SOUT.

The configurations and operations of the liquid crystal driver circuit 27 and the signal processing circuit 28 will be described below. In FIG. 5, the microcomputer 30 and the light receiving unit 2
A capacitor and a resistor are connected to the signal line between the signal line 6 and 6, but this is for removing noise on the signal line and protecting the circuit. In this embodiment, the capacitor and the resistor are provided on the printed circuit board 16. There is.

First, the liquid crystal driver circuit 27 comprises a row electrode driving circuit for driving the row electrodes of the liquid crystal panel 25 and a column electrode driving circuit for driving the column electrodes. Both the row electrodes and the column electrodes are driven at one time. A predetermined voltage necessary for transmitting light is applied to the pixel.

Then, the row electrode drive circuit sequentially applies a voltage to each row electrode for a predetermined time period for driving one pixel, while
The column electrode driving circuit operates so as to sequentially apply a voltage to each column electrode for a time period during which the row electrode driving circuit drives the m number of row electrodes. As a result, the m arranged in the first row
Pixels are sequentially driven, then m pixels arranged in the second column are sequentially driven, and all the pixels are driven one pixel at a time for a predetermined time, and the driven pixels are driven. Light is transmitted only for a while.

On the other hand, the signal processing circuit 28, as shown in FIG. 6, has a photodiode D biased by a power supply voltage.
And a detection circuit K configured by a detection resistor R that detects a current output from the photodiode D when illuminated with light, and a terminal voltage VC appearing at a terminal of the detection resistor R are sampled and held at a predetermined timing. , A sample-hold circuit 32 that outputs this as a detection signal SOUT indicating the amount of light received by the photodiode D, and a timing generation circuit 34 that outputs the timing at which the terminal voltage VC of the detection resistor R is sampled by the sample-hold circuit 32.
And consists of.

Then, a detection current corresponding to the amount of received light flows from the photodiode D and is converted into a voltage value by the detection resistor R. In the sample hold circuit 32, the timing signal S output from the timing circuit 34 after a predetermined time has elapsed from the start of driving one pixel of the liquid crystal panel 25.
A signal obtained by amplifying the terminal voltage VC of the detection resistor R is sampled in accordance with AM, the signal is held until the next sampling, and this signal is output as a detection signal SOUT indicating the amount of light received by the photodiode D. That is, the detection signal SOUT increases in accordance with the amount of light received by the photodiode D, the greater the amount of light received, and if no light strikes the photodiode D, no detection current will flow, so that the detection resistor R The terminal voltage VC does not appear and the detection signal SOUT becomes 0V.

Then, such processing in the signal processing circuit 28 is repeatedly executed every time the liquid crystal driver circuit 27 drives one pixel. Therefore, as shown in FIG. 7, the signal processing circuit 28 sequentially outputs the detection signal SOUT indicating the amount of received light in each pixel of the liquid crystal panel 25.

The first m pixels of the detection signal SOUT are transferred to the photodiode D by scanning the m pixels arranged in the first column in the pixels of the liquid crystal panel 25 arranged in a matrix. Represents the amount of received light detected by the detection signal SOU, and the next m pixels represent the result of scanning m pixels similarly arranged in the second column.
T represents the result of sequentially scanning each pixel of the liquid crystal panel 25 for each column (pixel column). Then, the detection signal SOUT of the pixel row including the pixels irradiated with light has a voltage due to the reception of the pinhole light B shown in FIG. 4, and among them, the detection signal level becomes closer to the pixel located closer to the irradiation center. Grows larger.

Therefore, the microcomputer 30 for detecting the solar radiation intensity and direction (incident angle φ and elevation angle θ of sunlight) using the optical position detecting device 1 of this embodiment first operates the optical position detecting device 1. By doing so, the detection signal SOUT sequentially output from the optical position detecting device 1 is sampled for each pixel, and the sampled detection signal SOUT is sampled.
Among them, the pixel row including the pixel with the highest level is detected, and the central pixel row j is detected. Further, the center pixel G (Xi, Yj) of the highest level pixel in the center pixel column j is detected. Then, the deviation of the central pixel G (Xi, Yj) from the pixel G (XP0, YP0) corresponding to the reference position P0 on the liquid crystal panel 25 shown in FIG. 4 is obtained to obtain the central pixel G (Xi, Yj) is the vector X indicating the sun direction
Components are converted into components and Y components, and the intensities I and directions of the solar radiation (incident angle φ and elevation angle θ) are calculated using the conversion results X and Y.

The following equations (1) to (4) are used for this calculation.

[0030]

[Equation 1]

That is, as shown in FIG. 4, the elevation angle θ'obtained from the pinhole light B incident on the liquid crystal panel 25 is an intermediate medium between the pinhole 24a and the liquid crystal panel 25, that is, the glass substrate 22 and the silicone gel. Since it is affected by the refractive index k of 29, first, the elevation angle θ ′ in the intermediate medium is obtained by the above equation (1), and the value θ ′ and the refractive index k (=
(2) above with cos θ / cos θ ′) as parameters
The elevation angle θ of the sunlight is calculated using the formula.

In the equation (1), t is the distance between the pinhole 24a and the liquid crystal panel 25, in other words, the thickness of the intermediate medium composed of the glass substrate 22 and the silicone gel 29. Further, when the elevation angle θ of sunlight is calculated using the above formula (2), the silicone gel 29 is much thinner than the glass substrate 22, and therefore the silicone gel 29 is also made of glass having a refractive index of 1.5. Assuming that the substrate 22 is used, the refractive index k in the above equation (2) is calculated as the glass substrate 22.
There is no problem even if the elevation angle θ is calculated assuming that the refractive index is 1.5.

Next, since the incident angle φ is not affected by the refractive index k of the intermediate medium, it is obtained by using the above equation (3). As for the solar radiation intensity I, the solar radiation intensity Io on the central pixel G (Xi, Yj) is obtained by converting the voltage value of the central pixel G (Xi, Yj) that changes depending on the intensity of light, and this is calculated. It is obtained by substituting in the above equation (4).

As described above, in the optical position detecting device 1 of the present embodiment, sunlight (pinhole light) transmitted through the pinhole 24a is applied to the liquid crystal panel 25 that operates as an optical shutter, and a predetermined amount is obtained. LCD panel 2 at the timing
Each pixel 5 is driven so that light is sequentially transmitted, and the light transmitted through the liquid crystal panel 25 is detected by one photodiode D.

Therefore, according to the present embodiment, the detection circuit for extracting the detection signal corresponding to the amount of received light from the photodiode D can be configured without including an analog switch, and the light irradiation unlike the conventional device can be performed. As a result, the characteristic of the analog switch or the like forming the detection circuit does not change and the level of the output signal does not change, and accurate detection can be performed.

That is, it is necessary to provide a detection circuit for taking out a detection signal of the photodiode in the vicinity of the photodiode for detecting the amount of received light, and in the conventional device in which a plurality of photodiodes are two-dimensionally arranged, An analog switch or the like is provided in each detection circuit to selectively extract output from each photodiode in order to detect the position where the light is irradiated by checking which photodiode received the light when the light is irradiated. Although it was necessary in this embodiment, since the position where the light is irradiated is detected by checking the pixel of the liquid crystal panel 25 which is driven when the photodiode D detects the light, the received light amount is 1
It suffices to detect with only one photodiode D, and the detection circuit K can be configured without including an analog switch whose characteristics change due to light irradiation.
Since the liquid crystal driver circuit 27 for driving the pixels of FIG. 3 only needs to drive the row electrodes and the column electrodes, the liquid crystal driver circuit 27 can be arranged at a position where the light is not irradiated to the edge portion of the liquid crystal panel 25.

Therefore, the optical position detecting device 1 of this embodiment is
Since it operates without being affected by light irradiation, accurate detection can be performed no matter how the light is irradiated. Furthermore, in this embodiment, the pinhole 24a
The glass substrate 22 and the silicone gel 29 are disposed between the liquid crystal panel 25 and the liquid crystal panel 25. Since pinhole light enters the liquid crystal panel 25 through the glass substrate 22 and the silicone gel 29, the pinhole 24a LCD panel 2
5, the liquid crystal panel 2 with respect to the change in the incident angle of the sunlight on the pinhole 24a, as compared with the case where the space between 5 and 5 is simply formed.
The change in the light receiving position on the liquid crystal panel 5 is reduced, and the liquid crystal panel 25 and the photodiode D provided below the liquid crystal panel 25 can be downsized.

Here, in the above embodiment, the liquid crystal panel 25 is provided directly on the photodiode D, but
As shown in FIG. 8, the liquid crystal panel 25 and the photodiode D
A convex lens 40 may be arranged between the and. In this case, since the light transmitted through the liquid crystal panel 25 is collected, the photodiode D provided below the liquid crystal panel 25 can be further downsized.

In the above embodiment, the photodiode D is used as the element for detecting the amount of received light.
Not only the photodiode D but also a charge coupled device (CCD)
It is possible to use various kinds of light receiving devices known in the related art, such as using. Further, in the above-described embodiment, the light-shielding film 24 is provided with the pinhole 24a. However, as shown in FIG. 9, an L-shaped slit 24b may be formed by intersecting two slits at one end.

Then, such an L-shaped slit 24 is formed.
When b is formed, the liquid crystal panel 25 does not need to have a two-dimensional expansion, and the liquid crystal panel 2 is formed in one row so as to be orthogonal to the two slits forming the L shape.
It is sufficient to arrange 5X and 25Y, and each liquid crystal panel 25
The irradiation position can be detected by detecting the central pixel of the pixels irradiated in X and 25Y. In this case, since the liquid crystal panels 25X and 25Y have a small number of pixels, the liquid crystal drive circuit can be simplified. Moreover, since the amount of detected signal is small, the processing of the detected signal is simplified.

Although the embodiment in which the optical position detecting device of the present invention is applied to a so-called solar radiation sensor for an automobile air conditioner has been described above, the optical position detecting device of the present invention is not limited to such a so-called solar radiation sensor. It can also be used as, for example, an optical position sensor that detects the incident direction and intensity of light from a predetermined light source, or a position sensor that further detects the mounting position of the sensor with the light source as the reference position from the detection result. .

[0042]

As described above, in the optical position detecting device of the present invention, the light transmitting portion is arranged opposite to the light shielding plate, and the light incident from the light entrance of the light shielding plate is the liquid crystal element. Of the pixels are radiated to the light transmitting portion arranged two-dimensionally, and further, the light transmitted through the light transmitting portion that is sequentially driven so that any one of the pixels transmits the light is transmitted to the light receiving element portion. It is configured to receive light.

Therefore, according to the light position detecting device of the present invention, the light irradiation position can be found by checking the pixel of the light transmitting portion which is driven when the light is detected in the light receiving element.
Unlike the conventional device, it is not necessary to provide a plurality of light receiving elements in the light receiving element section, and the light receiving element section can be configured without including an analog switch whose characteristics change due to light irradiation.

Therefore, the optical position detecting device of the present invention operates without being affected by the irradiation of light, so that accurate detection can be performed regardless of how the light is irradiated.

[Brief description of drawings]

FIG. 1 is an explanatory diagram illustrating a configuration of a detection element unit 10 of a light position detection device 1.

FIG. 2 is an explanatory diagram showing how the optical position detecting device 1 is attached to an automobile.

FIG. 3 is a cross-sectional view showing the overall configuration of the optical position detection device 1.

FIG. 4 is an explanatory diagram for explaining an incident state of sunlight in the light position detection device 1.

FIG. 5 is an explanatory diagram illustrating a connection state between the optical position detection device 1 and a microcomputer 30 for air conditioning control.

FIG. 6 is a block diagram showing a configuration of a signal processing circuit 28.

FIG. 7 is a detection signal S output from the signal processing circuit 28.
It is explanatory drawing showing OUT.

8 is an explanatory diagram illustrating a configuration example in which a convex lens 40 is inserted between the liquid crystal panel 25 and the photodiode D. FIG.

FIG. 9 is an explanatory diagram illustrating another configuration example of the detection element unit 10.

FIG. 10 is an explanatory diagram illustrating a configuration of a detection circuit in a conventional device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical position detection device 10 ... Detection element part 12 ... Clip terminal 14 ... External connector 16 ... Printed circuit board 18 ...
Cylindrical casing 20 ... Light transmitting filter 22 ... Glass substrate 24
... Light-shielding film 24a ... Pinhole 25 ... Liquid crystal panel 26 ... Light receiving part 27 ... Liquid crystal driver circuit 28 ... Signal processing circuit 29 ... Silicone gel 30 ... Microcomputer D ... Photodiode

Continuation of the front page (56) Reference JP-A-5-52921 (JP, A) JP-A-4-104019 (JP, A) JP-A-3-50017 (JP, A) JP-A-6-117924 (JP , A) JP-A-5-289815 (JP, A) JP-A-2-264320 (JP, A) JP-A-63-205724 (JP, A) Practical application Sho-64-46722 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B60H 1/00 101

Claims (3)

(57) [Claims] 1. A light-shielding plate having a light-introducing port formed therein, and a pixel of a liquid crystal element , which is disposed opposite to the light-shielding plate at a predetermined interval and which transmits / blocks light in accordance with an applied electric field. Two
A light transmission section arranged in a dimension, and a transmission control section sequentially driving the pixels of the liquid crystal element so that any one of the pixels of the liquid crystal element arranged in the light transmission section transmits light, A light-receiving element portion for receiving light transmitted through the light-transmitting portion, and the light- receiving element portion detected by the output signal of the light-receiving element portion.
Received light intensity of light applied to the light-receiving element section, and the transmitting section
The intensity of the incident light and
An optical position detector characterized by detecting an incident direction . 2. The light inlet of the light shielding plate is a pinhole.
Made, the light-transmitting portion, pixels are formed in a matrix liquid crystal
The light position according to claim 1, characterized by comprising a panel.
Detection device. 3. The light inlet of the light-shielding plate has a double-threaded slit.
It consists of an L-shaped slit that intersects at one end, The light-transmitting part has two liquid crystal panels formed in a line.
Directly to the two slits forming the L-shape.
Characterized by being arranged to intersect
The optical position detecting device according to claim 1.