JPH08228179A - Light receiving module - Google Patents

Abstract

(57) Abstract: An object of the present invention is to provide a light receiving module which can obtain a good light receiving sensitivity characteristic in a wide range. According to the present invention, a plurality of light receiving elements 11 provided in different directions, and a widening device 200 that receives a sum of outputs of the plurality of light receiving elements 11 and widens only a signal having a predetermined frequency width. It is characterized by having. Also, the present invention
A plurality of light receiving elements 11 which are provided in different directions and which receive modulated light rays such as infrared rays and photoelectrically convert the light rays, and an output sum of the plurality of light receiving elements 11 are amplified to increase only a signal having a predetermined frequency width. And a thickening device 200, which has a notch filter characteristic in the vicinity of the fundamental frequency of the modulation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light receiving module suitable for a control device using an optical signal.

[0002]

2. Description of the Related Art Conventionally, modulated light rays such as infrared rays have been used for remote control operations in air conditioners, television receivers and the like. In this case, JP-A-58-204573 and JP-B-61-17643 are used. As described in Japanese Patent Laid-Open Publication No. 2004-242242, it has a light receiving element that receives the light and performs photoelectric conversion, and a widening device that widens the output of the photoelectric conversion element. Since this amplifier has a large amplification factor of about 80 to 90 dB so that it can respond even if the optical signal is weak, it is vulnerable to noise.

[0003]

The noise is usually dealt with by using a shield case or a filter. However, in the above-described modulation of infrared rays and the like, since a transmitter such as a remote controller is often a low power mobile type, a relatively simple modulation method is adopted and a weak signal is generated.
Therefore, even if a shield case is used,
It was necessary to satisfy certain requirements in consideration of directionality, etc., and it was not possible to provide a sharp filter characteristic in consideration of oscillator power fluctuations and oscillation during movement.

For this reason, the widened waveform is shaped to obtain a constant O
Even if the N / OFF signal is taken out, the extracted signal still has a high frequency superimposed on it as shown in FIG. 7, which causes the control circuit of the device to make a judgment error. Of these high frequencies, the most frequent are the noise of the flyback transformer of the television receiver (near 16.6 KH _Z ) and the driving of the fluorescent lamp (100 to 120).
Harmonic components of H _Z) (2KH _Z ~6KH _Z was confirmed experimentally)
Met. In addition, in recent years, fluorescent lamps and the like are often turned on at a high frequency, and these generate noise electromagnetically and electromagnetically, so it is difficult to remove this noise with the filter characteristics having a low sharpness (Q). there were. Furthermore, a large circuit is required to shape the output once amplified by the light receiving module inside the equipment and extract the signal wave of the specific frequency component. At this time, noise is more likely to be added to the signal line. Therefore, mounting the light receiving module on the device was a complicated task.

In the equipment using these light receiving modules, particularly in the upper part of the room (ceiling or wall near the ceiling)
When installed at, the influence of noise has increased because the light from the transmitter such as a remote controller is difficult to identify and receive.

In view of the above points, the present invention has a main object to provide a light receiving module which can obtain a good light receiving sensitivity characteristic in a wide range.

[0007]

DISCLOSURE OF THE INVENTION The present invention is directed to a plurality of light receiving elements provided in different directions, and a width increasing means for receiving a sum of outputs of the light receiving elements and increasing only a signal having a predetermined frequency width. It is characterized by having a container.

Further, according to the present invention, a plurality of light receiving elements which are provided in different directions and receive a modulated light beam such as an infrared ray and photoelectrically convert it, and a predetermined frequency for receiving the output sum of the plurality of light receiving elements. A widening device for widening only a signal having a width is provided, and the widening device has a notch filter characteristic in the vicinity of the fundamental frequency of the modulation.

[0009]

1 is a sectional view of a light receiving module according to an embodiment of the present invention, and FIG. 2 is a block diagram thereof. In these figures, (1) is a light-receiving element that receives a modulated light beam such as infrared rays and photoelectrically converts it by reverse biasing, such as a silicon PIN photodiode, a phototransistor,
It consists of a pyroelectric element and the like. (2) is an amplifier that amplifies the output of the light receiving element (1), for example, an amplifier (21), a filter (22),
It consists of detection (23) and waveform shaping (24) circuits.
6), a block resistor (27), a capacitor (28), etc. and is fixed to the substrate (3) together with the light receiving element (1). The output of the amplifier (2) is output as it is or via a transistor. (5) is these light receiving element (1) and amplifier (2)
In a shield case containing a light receiving window (6), which is formed of a through hole, a mesh hole or a light transmitting electromagnetic shield film,
Only the terminal pins (7), (7), (7) implanted in (3) protrude from the shield case.

In such a configuration, the amplifier (2) has an amplification factor of 80 to 90 dB around the fundamental frequency of modulation of infrared rays and the like, and has notch filter characteristics in the vicinity of the fundamental frequency. There is. More specifically, as shown in FIG. 3, the amplifier (2) includes an operational amplifier (2a) which constitutes a bandpass filter having an amplification factor and an operational amplifier (which constitutes a notch filter having a high Q). 2b) (2b). In such a configuration, the modulation frequency f _O = 37 to 40 KH _Z , Q = f _O / ([ff _B ] × as the center frequency of the bandpass filter.
2) = 10 to 15 are selected and set (note that [A] indicates the absolute value of A.), and the center frequency f ₁ of the notch filter (the series resistance of the double T bridge is R, the branch resistance is R / 2, respectively). , When each series capacitor is C and each branch capacitor is 2C, f ₁ = 1 /
2πRC) 48-52KH _Z which is often used for high frequency lighting fluorescent lamps
If selected and set to, the amplifier characteristics as shown by the solid line in FIG. 4 can be obtained. Thus, for example 38KH _Z can be maintained the property that more than -10dB in rice 20KH _Z ~43KH _Z peak.

With respect to the above-mentioned high-frequency components shown in FIG. 7, a light-receiving module is arranged in front of a fluorescent lamp, in front of a neon tube or the like which is directly irradiated with illumination light, and a noise figure with respect to a remote control signal and a judgment error of a control circuit occur. I examined the rate. Consequently 50H _Z or 60H _Z despite the using commercial power, high noise frequency of incidence of determination errors of a commercial frequency
It is 100 times the harmonic from 40 times, particularly 2KH _Z ~6KH _Z range (neon tubes 2.2~2.4KH _Z) was substantially gain 30dB~40dB in. Therefore, such noise at a distance from the center frequency f _O can be removed by reducing the sharpness Q of the bandpass filter to deal with it. And even more preferable to attenuate the following 17KH _Z noisy f ₂ ≒ 16.6KH _Z of the flyback transformer in characteristics such as shown by the broken line in FIG. 4 by the high-pass filter (low-cut filter).

[0012] In this way, when selectively increasing the increasing width ratio of Zohaba instrument at approximately 20～43KH _Z, since the operation even near such appliances using commercial frequency is ensured, for example, the ceiling lamps It can be used as a light-receiving module for an optical remote controller with very few malfunctions even in a ceiling-mounted air conditioner installed nearby.

However, in the equipment installed above the remote controller, the elevation angle from the remote controller (transmitter) to the light receiving module is large, and the effective light receiving angle of the light receiving module is too narrow with respect to the movement of the operator. However, in such a case, the light receiving distribution of the light receiving module itself may be expanded instead of using two light receiving modules. One method is to cover the silicon light-receiving pellets in the light-receiving element with an amorphous film having a refractive index of 3 or more. However, it is simpler and more effective to use two light receiving elements in the light receiving module.

FIGS. 5 and 6 show a sectional view and a block diagram of such a light receiving module, in which the light receiving elements (11) and (11) are provided in different directions (X) and (Y), and a shield case is provided.
(50) has a light receiving window (60) on the top surface and a total of 5 surfaces around it,
When the aperture ratio of the light receiving window (60) is large, the light transmissive electromagnetic shield film (61) is provided along the inner wall of the shield case (50). The light receiving elements (11) and (11) are connected in parallel, and the output terminal of the amplifier broadens only the signal of a predetermined frequency width (200).
, The output sum of the two light receiving elements (11) and (11) is input to the amplifier 200.

More specifically, the light receiving element (1
(1) and (11) are light receiving elements (11) and (11) with an effective light receiving angle of ± 45 degrees, arranged and fixed so that their light receiving surfaces are orthogonal to each other.
It is connected to the first stage amplifier (201) of (200). Magnifier (20
In addition to the first stage amplifier (201), 0) is a limiter (202), bandpass filter (203), detector (204), and waveform shaping circuit (20).
Consists of 5), the sharpness Dosa of Q of the bandpass filter (203), or well in the frequency band 20～45KH _Z by bandwidth limitations and combinations or bandwidth limit and the notch filter and the combination of the high-pass filter of the notch filter a gain is made so as to obtain, as a whole 2～17KH _Z to the peak value, the frequency band more than 60dB attenuation at the 48～52KH _Z of the amplifier (200), for example, a _{f = 2.4 kHz} -60 dB ≦ A _{f = 40KHZ} ≧ A
_The constant is set so that _{f = 50KHz} -60dB.

In such a light receiving module, the light receiving sensitivity characteristic (azimuth dependence) of each light receiving element (11) (11)
(A) The center of (A) is oriented in the X-axis and Y-axis directions, but even in the intermediate direction S-axis, high photosensitivity (B) is obtained as the output sum of the two photodetectors (11) (11). To be This is a light receiving element
(11) Considering the case where the magnitude of the photocurrent in (11) or the magnitude of the voltage drop that occurs depending on the magnitude of the photocurrent is guided to the first-stage amplifier (201), the X-axis or Y-axis Light-receiving element that is either in front of incident light from any direction
(11) While the saturation current flows in (11), both light receiving elements (11) (1
Since the operating current i of 1) flows, the first-stage amplifier (201) is equivalent to the operating current of approximately 2i flowing through one light receiving element, and also has a role of averaging the noise component due to the phase difference due to reflection or the like. . Therefore, the output of the amplifier (200) has excellent light-receiving sensitivity characteristics, which cannot be obtained when two light-receiving modules are arranged in two places in the same form, even with respect to the S-axis in the intermediate direction. As a result, reliable light reception control can be performed even when there is a lighting device in front of the air conditioner, such as the ceiling of a general household, and the remote controller moves greatly in the room.

[0017]

As described above, the light receiving module of the present invention comprises a plurality of light receiving elements provided in different directions,
Since it is equipped with an amplifier that receives the output sum of the multiple light-receiving elements and widens only the signals of a predetermined frequency width, the light-receiving sensitivity characteristic (azimuth dependence) of each light-receiving element is in the middle direction of the center direction. In addition, since a high light receiving sensitivity can be obtained as the sum of the outputs of the respective light receiving elements, and the noise component due to the phase difference due to reflection or the like can be averaged, when a plurality of light receiving modules are arranged in the same form, Can't get
Good light receiving sensitivity characteristics can be obtained. As a result, even if there is a lighting device in front of the air conditioner, such as the ceiling of a general household, and the remote controller moves greatly in the room, reliable light reception control can be performed.

Further, by providing the amplifier with a notch filter characteristic in the vicinity of the fundamental frequency of the modulation, the receiving sensitivity can be kept high with a certain frequency width around the modulation frequency, so that the signal of the oscillator fluctuates. Even if it is, it can be surely received.

[Brief description of drawings]

FIG. 1 is a sectional view of a light receiving module according to an embodiment of the present invention.

FIG. 2 is a block diagram of the light receiving module of FIG.

FIG. 3 is a circuit diagram of the amplifier of FIG.

FIG. 4 is a frequency characteristic diagram of the amplifier shown in FIG.

FIG. 5 is a sectional view of a light receiving module according to an embodiment of the present invention.

FIG. 6 is a block diagram of the light receiving module of FIG.

FIG. 7 is an output waveform diagram of a conventional light receiving module.

[Explanation of symbols]

 1 Light receiving element 11 Light receiving element 2 Magnifier 200 Magnifier 5 Shield case 500 Shield case

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H01L 31/02 31/10

Claims (2)

[Claims] 1. A plurality of light-receiving elements provided in different directions, and an amplifier that receives the sum of outputs of the plurality of light-receiving elements and increases only a signal having a predetermined frequency width. Light receiving module. 2. A plurality of light receiving elements, which are provided in different directions and receive photoelectrically converted light rays such as infrared rays, and a signal having a predetermined frequency width for receiving the output sum of the plurality of light receiving elements. A light-receiving module comprising: a widening device for increasing the width of the light receiving device, wherein the widening device has a notch filter characteristic in the vicinity of the fundamental frequency of the modulation.