JP4044911B2 - Receiver - Google Patents

Description

  The present invention relates to a light receiver that receives light such as infrared rays and generates an electrical signal corresponding thereto.

  In such a light receiver, a photodiode or a phototransistor is often used as a light receiving element. For example, a photodiode has a structure in which a semiconductor portion serving as a light receiving surface is exposed and has a high impedance, and thus has a considerable sensitivity to not only light but also electromagnetic waves. Therefore, electromagnetic shielding of the photodiode is performed. A configuration in which the photodiode is electromagnetically shielded is disclosed in Patent Document 1, for example.

  In Patent Document 1, a pedestal that forms a predetermined angle with respect to a substrate is provided on the substrate. A plurality of photodiodes are attached to the pedestal so that they can receive light from the direction in which light is received. One electromagnetic shielding case is attached to the substrate so as to cover all these photodiodes.

JP 2002-190617 A

  However, in the technique disclosed in Patent Document 1, it is necessary to form an electromagnetic shield case so as to cover all the photodiodes. Therefore, the apparatus using these light receivers becomes large.

  An object of this invention is to provide the light receiver which can reduce in size the apparatus in which the light receiver is used.

The light receiving device according to the present invention has one light receiving element that generates an electrical signal in response to light received by the light receiving unit. For example, a photodiode or a phototransistor can be used as the light receiving element. A frame-like body of the electromagnetic shield cover surrounds both sides and the upper part of the light receiving part of the light receiving element, and has a light receiving window at a position corresponding to the light receiving part. The lower end of the plate-like body connected to the lower part of the frame-like body is in contact with the substrate. The light receiving element is attached to the frame of the electromagnetic shield cover. The electromagnetic shield cover has a substrate fixing portion that extends to the rear of the frame-like body and extends to the lower side of the frame-like body and both sides of the plate-like body, and the lower portion of the substrate fixing portion is the frame-like body. Is formed at a predetermined oblique angle. The substrate fixing portion is engaged with a fixing portion of the substrate, and the lower portion of the substrate fixing portion is in contact with the substrate in this engaged state.

If comprised in this way, a light receiving element makes a predetermined angle by engaging a board | substrate fixing | fixed part with a fixing | fixed part. Therefore, the angle adjustment of the light receiving element can be simultaneously performed by the attaching operation of the shield case and the light receiving element in which the substrate fixing part is engaged with the fixing part, and the angle adjustment of the light receiving element becomes unnecessary. In addition, it is possible to give the light receiving element a predetermined angle without making any changes to the substrate or the like simply by preparing an electromagnetic shield cover corresponding to the angle to be given to the light receiving element. Further, since the angle accuracy of the light receiving element is determined by the accuracy of the electromagnetic shield cover, the angle accuracy of the light receiving element is much higher than that of the conventional one. In addition, the angle accuracy of the light receiving element can be sufficiently secured only by a simple operation of engaging the substrate fixing portion with the fixing portion of the substrate, and a special operation for ensuring the angle accuracy of the light receiving element is unnecessary. Yes, the assembly work becomes easy and the assembly cost is reduced. In addition, the cost of the electromagnetic shield cover is low, and the cost of the light receiver can be reduced.

Furthermore, the light receiving element can be attached to a mounting plate. This attachment plate is attached to the frame of the electromagnetic shield cover . Since the light receiving element is attached to the mounting plate, the light receiving element can be connected to the electric circuit on the substrate via the mounting plate.

  As described above, according to the light receiver according to the present invention, since the electromagnetic shield cover is provided for each light receiver, the device using the light receiver can be reduced in size.

  The light receiver of the first embodiment of the present invention is used in, for example, an infrared light emitting / receiving device. This infrared light emitting / receiving device is used, for example, in an infrared cordless microphone system. In an infrared cordless microphone system, bidirectional optical communication using infrared rays is performed between, for example, a transmission / reception set arranged on a desk in a conference hall and an infrared light emitting / receiving device provided on a ceiling, for example.

  In the infrared light emitting and receiving device, as shown in FIGS. 1 and 2, a plurality of light receivers 4 are annularly arranged on a substrate 2. The substrate 2 is a printed circuit board that is formed in a disk shape, for example, and has a predetermined circuit pattern on the surface opposite to the installation surface of the light receiver 4. Each light receiver 4 receives infrared rays transmitted from the above-described transmission / reception set and generates an electrical signal.

  As shown in FIG. 3, these light receivers 4 have light receiving elements, for example, photodiodes 6. The photodiode 6 is a flat type, and infrared rays are incident on a light receiving surface 6a which is a surface on the front side. A plurality of leads 8 protrude from the back side of the photodiode 6. The photodiode 6 is arranged with its back side in contact with a mounting plate, for example, a mounting surface of a small printed circuit board 10, and each lead 8 is connected to a predetermined position of a pattern formed on the small printed circuit board 10. Yes. Therefore, the light receiving surface 6a of the photodiode 6 and the mounting surface of the small printed circuit board 10 are parallel. In the small printed board 10, a terminal 12 for connection with the board 2 is arranged below the photodiode 6. One end of each pin 12 a of the connection terminal 12 is inserted into a predetermined position of the small printed circuit board 10 and connected to a pattern formed on the small printed circuit board 10. The other end of each pin 12 a is inserted into a predetermined position of the substrate 2, and the photodiode 6 is connected to a predetermined pattern on the substrate 2.

  An electromagnetic shield cover 14 is disposed on the light receiving surface 6 a side of the photodiode 6. The shield cover 14 is made of a conductive material, for example, iron or aluminum, can cover both sides and the top of the photodiode 6 and the connection terminal 12, and is slightly smaller than the small printed circuit board 10. It has a frame-like body 14a. A window 14b having a size corresponding to the light receiving surface 6a of the photodiode 6 is formed on the front side of the frame 14a. A cross-shaped lattice 14c is formed in the window 14b so as to divide the window 14b vertically and horizontally. A linear substrate fixing portion 14d is formed at the lower part on both sides of the frame-like body 14 so as to extend integrally therewith and backward. As shown in FIG. 4, the substrate fixing portion 14d and the frame-like body 14a are arranged so as to form a predetermined angle, for example, an acute angle θ.

  At the rear center of both sides of the frame-shaped body 14a and the rear center of the upper part, tongue pieces 14e extending linearly rearward are integrally formed. The tongue pieces 14e are inserted through insertion holes 10a formed in the small printed circuit board 10 correspondingly, and are fixed to the small printed circuit board 10 side by soldering or the like. As a result, as shown in FIG. 5, the electromagnetic shield cover 14 is attached to the small printed circuit board 10 with the window 14b of the electromagnetic shield cover 14 parallel to the light receiving surface 6a of the photodiode 6, and the light receiving surface of the photodiode 6 6 a is covered with an electromagnetic shield cover 14. That is, the electromagnetic shield cover 14 is attached to each photodiode. In addition, since the photodiode 6 is a flat plate and the light receiving surface 6a side of the photodiode 6 is close to this and covered with the electromagnetic shield cover 14, the thickness of the light receiver 4 can be reduced.

  Further, engaging portions, for example, tongue pieces 14f, are formed at both lower centers of the substrate fixing portion 14d, integrally therewith and perpendicular to the substrate fixing portion 14d. When attaching the light receiver to the printed circuit board 2, as shown in FIG. 6, the tongue piece 14f is engaged with a fixing portion formed on the board 2 corresponding to the tongue piece 14f, for example, an insertion hole (not shown), For example, the tongue piece 14 f is soldered to a reference potential pattern (not shown) formed on the substrate 2. In this soldering state, the lower portion of the fixing portion 14 d is in contact with the substrate 2, and the electromagnetic shield cover 14 and the photodiode 6 are attached with a predetermined angle θ with respect to the substrate 2. In addition, since the electromagnetic shield cover 14 is connected to the reference potential pattern, the electromagnetic shield is performed on the photodiode 6 by the electromagnetic shield cover 14.

  Since the light receiver is configured as described above, when the electromagnetic shield cover 14 of the light receiver is attached to the substrate 2, the photodiode 6 automatically forms a predetermined light receiving angle. Therefore, it is not necessary to adjust the light receiving angle of the photodiode 6 after mounting. In addition, the light receiving angle does not change, and even when the light receiving angle is attached to another substrate 2 having the same configuration, the light receiving angle is the same, and the light receiving angle does not vary from one substrate 2 to another. The substrate 2 is attached to the ceiling so that each light receiver 4 is positioned on the lower side. Therefore, it is possible to receive infrared rays transmitted from a transmission / reception set on a desk or the like.

  In this infrared light emitting / receiving device, as shown in FIG. 1, a plurality of light emitting elements, for example, a plurality of LEDs 16, are attached inside the respective light receivers 4 so as to form a predetermined angle with respect to the substrate 2. ing. These LEDs 16 project infrared rays toward the transmitting / receiving set on the desk in a state where the substrate 2 is attached to the ceiling as described above. Although not shown, an infrared transmission type cover is attached so as to cover each light receiver 4 and the LED 16 on the substrate 2.

  In the above embodiment, each light receiver 14 and LED 16 are separately attached to the substrate 2. However, for example, the tip of the small printed circuit board 10 can be further extended, and the LED 16 can be attached to the extended portion. In this case, by attaching the shield cover 14 to the substrate 2, not only the light receiver 4 and the LED 16 can be attached at the same time, but also the light receiver 4 and the LED 16 can be simultaneously set to predetermined angles without any angle adjustment. Can do.

  The light receiver 4 of the above embodiment is provided with the electromagnetic shield cover 14 separately from the photodiode 6, but the light receiver 4 a of the second embodiment is integrated with the photodiode 60 and the electromagnetic shield cover 140. Is provided. That is, as shown in FIGS. 7A and 7B, the entire region of the photodiode 60 is accommodated in a housing 62 made of an infrared transmitting resin. An electromagnetic shield cover 140 is disposed in the housing 62 so as to be positioned in front of the light receiving surface 60a of the photodiode 60 with a predetermined interval. The electromagnetic shield cover 140 is formed in a lattice shape from a conductive material, and is disposed so as to cover the entire light receiving surface 60 a of the photodiode 60. A lead 142 is connected to the electromagnetic shield cover 140. The lead 142 is led out of the casing 62 and connected to a reference potential. In FIGS. 2A and 2B, the lead to the photodiode 6 is omitted. FIG. 2C is an equivalent circuit diagram of the light receiver 4a.

  Also in the light receiver 4a of this embodiment, since one electromagnetic shield cover 140 is provided for one photodiode 60, the light receiver 4a is further downsized than the light receiver 4 of the first embodiment. be able to. Therefore, an infrared light emitting / receiving device which is an example of a device using the light receiver 4a can be further downsized.

  In the light receiver 4a of the second embodiment, a lead 142 is provided to connect the electromagnetic shield cover 140 to a reference potential. However, the photodiode 60 is normally used in a reverse bias state, and its cathode is connected to the reference potential in an alternating manner. Therefore, if the electromagnetic shield cover 140 is connected to the cathode in the housing 62 as shown in FIG. 8, there is no need to provide the lead 142.

  In the above embodiment, the photodiode is used as the light receiving element. However, the present invention is not limited to this. For example, a phototransistor can be used.

1 is a perspective view of an infrared light emitting and receiving device using a light receiver according to an embodiment of the present invention. FIG. 2 is a side view of the infrared light emitting / receiving device of FIG. 1. FIG. 2 is an assembly diagram of the light receiver in FIG. 1. It is a side view of the light receiver of FIG. It is a perspective view of the light receiver of FIG. It is a side view of the state which attached the light receiver of FIG. 1 to the board | substrate. It is the front view of the light receiver of the 2nd Embodiment of this invention, a side view, and an equivalent circuit schematic. FIG. 8 is an equivalent circuit diagram of a modification of the light receiver in FIG. 7.

Explanation of symbols

2 Substrate 4 Receiver 6 Photodiode (light receiving element)
10 Small printed circuit board (mounting plate)
14 Electromagnetic shield cover 140 Electromagnetic shield cover

Claims (2)

One light receiving element that generates an electrical signal in response to light reception by the light receiving unit;
The frame includes a frame-like body that surrounds both sides and an upper portion of the light-receiving portion of the light-receiving element, has a light-receiving window at a position corresponding to the light-receiving portion, and has the light-receiving element attached thereto. An electromagnetic shield cover in which the lower end of the plate-like body connected to the substrate is in contact with the substrate ,
Comprising the electromagnetic shield cover has a substrate fixing portion lower and lined on either side of the plate-like member extending rearward of the frame-like member of the frame-like member, the substrate fixing portion, the lower portion is the The substrate fixing portion is formed to form a predetermined oblique angle with respect to the frame-like body, and the substrate fixing portion is engaged with the fixing portion of the substrate. In this engaged state, the lower portion of the substrate fixing portion is the substrate. Receiver in contact with The light receiving device according to claim 1, wherein the light receiving element is attached to the frame body by attaching the light receiving element to an attachment plate and attaching the attachment plate to the electromagnetic shield cover.

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