JPH01233992A - Receiver - Google Patents

Abstract

PURPOSE:To expand a light receiving angle by providing a photodetector receiving a signal light and contained in a shield case and a lens formed with a recessed part to increase the refractive index of the lens to a face of the side of the photodetector to make a signal light incident into the photodetector and increasing the refractive index of the lens even with a thin lens. CONSTITUTION:A photodetection window 15 introducing a signal light is formed to a photodetector 11 is formed to a shield case 12 and a lens 14 condensing the signal light is arranged to the photodetecting face of the photodetector 11 is arranged on the photodetection window 15. The part of the lens 14 at the flat lower face corresponding to the photodetector 11 is recessed inward to increase the refractive index of the signal light by the recessed part 14a. Moreover, the curved face shape of the recessed part 14a of the lens 14, the thickness of the lens 14 and the rate of the recess of the recessed part 14a are selected by a position of the signal light desired to be condensed and the required photodetection angle. Thus, the position of the photodetector 11 is set comparatively freely. Furthermore, even if the thickness of the lens is thin, the refractive index of the lens is increased and the light receiving angle is widened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a receiver used in a spatial signal transmission device that uses light as a transmission medium.

[Prior Art] This type of receiver A is attached to a ceiling 13 to receive light from a transmitter, as shown in FIG. This receiver A needs to obtain a wide light receiving angle θ, and in some cases, the light receiving angle θ may be required to be up to ±90°. For this reason, in the past, multiple light receiving elements 1 were used as shown in Figure @9.
1 was used to obtain a wide acceptance angle θ. By the way, in order to improve the distance characteristics of this type of receiver, the gain of the light receiving section is increased. For this reason, the light receiving section becomes susceptible to the effects of noise, so it is necessary to provide a shield. However, if the structure is such that a wide light receiving angle θ is obtained by a plurality of light receiving elements 11 as described above, the ninth
As shown in the figure, the light receiving element 11 comes out of the shield case 12, making it susceptible to noise. In other words, there was a problem in that transmission reliability deteriorated.

[Problem to be solved by the invention 1 The present invention has been made in view of the above-mentioned 4α, and its purpose is to obtain a wide light receiving angle,
The object of the present invention is to provide a receiver that can ensure high transmission performance.

[Means for Solving the Problems 1] In order to achieve the above object, the specific invention includes a light receiving element that is housed in a shield case and receives signal light, and a light receiving element that is formed in the shield case to make the signal light enter the light receiving element. The lens is disposed above the light-receiving window and has a recess formed on the surface facing the light-receiving element to increase the refractive index of the lens.

Further, the related invention includes a light receiving element that is housed in a shield case and receives signal light, and a lens that is disposed above a light receiving window formed in the shield case to input the light into the light receiving element. , a filler having a large refractive index is filled between the light receiving element and the lens.

(Function) The specified invention reduces the influence of noise on the light receiving element by housing the light receiving element in the shield case as described above, and also reduces the effect of noise on the light receiving element side of the lens through which the signal light enters the light receiving element. By forming a recess in the lens, the refractive index of the lens is increased even when the lens is thin, and the light receiving angle is widened.

In addition, a related invention is to fill the space between the light receiving element and the lens with a filler having a large refractive index, thereby making it difficult for total reflection to occur at the interface between the lens and the filler, thereby widening the light receiving angle. This is what I did.

(Example 1) An embodiment of the specific invention is shown in FIGS. 1 to 7.

The optical transmitter/receiver equipped with the receiver of this embodiment is a remote monitoring control device that connects a central control device and a terminal device with a pair of signal lines, and performs time-division multiplex transmission of control data, monitoring data, etc. to remotely control a load. It is used in the system.

In this remote monitoring and control system, as shown in FIG.
The transmission signal Vs is sent from the central control device 4 to each terminal device 5.6 via the signal line 7, and the switches 81 to S
, and the operating states of the loads L1-L, and control the operations of the loads L1-L. This transmission signal V
As shown in FIG. 5, s is a start pulse signal ST indicating the start of signal transmission, and a mode data signal M indicating the signal mode.
D, address data signal AD for calling terminal devices 5 and 6;
A bipolar (±24v
) is a time division multiplexed signal that transmits data using pulse width modulation.

When the address data of the transmission signal Vs received via the signal 1j17 matches its own unique address data, each terminal device 5, 6 takes in the control data of the transmission signal Vs and returns the transmission signal Vs. In synchronization with the standby signal WT, the monitoring data signal is sent back as a current mode signal (a signal sent by short-circuiting signals #14 through an appropriate low impedance).

Next, an optical transmitting/receiving device that transmits and receives light using infrared rays or the like will be described. As shown in FIG. 4, this optical transmitting/receiving device is comprised of a transmitter B and a receiver A that receives signal light from the transmitter B. A unique address is set for each transmitter B, and control data for controlling on/off of loads such as lighting equipment is transmitted together with the address data as a transmission code as a signal light as shown in Fig. 6 (,). Sent. As shown in FIG. 7, the transmission code of this signal light includes address data AD and control data C.
It consists of D. Here, the mode data SI in front of the address data AD is a mode for selecting whether to perform other system operations such as a time division multiplex transmission remote control system, or to perform individual operations by the optical transmitter/receiver. .

Receiver A receives the optical signal from transmitter B with a light receiving element 11 such as a PMN diode, converts it into a baseband signal as shown in FIG. 6(1), and outputs it. The baseband signal from this reception BA is sent out on a dedicated signal line 10 and transmitted to the system receiver 9 and a plurality of individual receivers 8 connected to this signal line 10. The system receiver 9 receives the baseband signals from the receiver A all at once, and the individual receivers 8 compare the baseband signal with the setting address of each individual receiver 8, and if they match, the lighting equipment This is to control the load such as.

The signal light emitted from the transmitter B is received by the nearest receiver A, converted to a baseband signal, and transmitted to each receiver 8,
9 via wired signal #110. If the mode data SI of the transmission hood selects individual operation, the system receiver 9 does not respond and the individual receiver 8 becomes the target.

Each individual receiver 8 checks the address of the baseband signal, and if it matches the set address, controls the load operation. Here, if the mode data SI of the signal light from the transmitter B selects system operation, the system receiver 9 will respond. In other words, processing is performed according to the procedure of the multiplex transmission remote monitoring and control system described above.

By the way, in the receiver A of this embodiment, the shield case 12
One light-receiving element 11 is disposed inside the light-receiving section to reduce the influence of noise on the light-receiving section. A light-receiving window 15 is formed in the shield case 12 to introduce signal light into the light-receiving element 11, and a lens 14 is disposed above the light-receiving window 15 to fully focus the signal light on the light-receiving surface of the light-receiving element 11. . Such a lens 14 needs to be thin due to its design, and cannot obtain a sufficient refractive index for signal light. Therefore, in this embodiment, the portion of the flat lower surface of the lens 14 corresponding to the light receiving element 11 is recessed inward. In other words, this recess 14a increases the refractive index of the signal light. Note that the curved shape of the recess 14a of the lens 14, the thickness of the lens 'X14, and the recess 1
The recess ratio of 4a is determined based on the position where the signal light is desired to be focused and the required light receiving angle. Providing the recess 14a on the lower surface of the lens 14 as in this embodiment has the advantage that the position of the light receiving element 11 can be set relatively freely. In addition, the space between the light-receiving cable 11 and the lens 14 is filled to prevent an air layer from forming.
There is also an advantage α in which it is not necessary to apply ftM. In other words, as shown in FIG. 11, when a lens 14'' without a recess 14a on the lower surface is used and there is an air layer between the lens X14'' and the light receiving element 11, the lens 14'' is This is because, if the lens 14' is designed, total reflection will occur at the interface between the lens 14' and the air layer, making it impossible to obtain the required amount of received signal light.

(Embodiment 2) FIG. 8 shows an embodiment of the related invention. In the specific invention described above, the recess 14a was formed on the lower surface of the lens 14 so that a sufficient light receiving angle could be obtained even if the lens:X:14 was thin, but in the present invention, the lens is A filler 16 that prevents the formation of an air layer between the lens 14 and the light-receiving element 11 makes it possible to obtain a sufficient light-receiving angle even with a thin lens 14. . Conventionally, a silicon-based filler, which is easy to handle, is used as the filler 16. Since this silicon-based filler has a low refractive index, the signal light cannot be refracted sufficiently by the lens 14 alone, and the light receiving probe 11 Not enough signal light was received. In order to increase the refractive index, it is conceivable to use a lens 14' with a large refractive index, but when refractive index and cost are considered, only plastic lenses can be used, leaving no room for material selection. Therefore, it is not a good idea to use a lens 14 with a large refractive index. Note that the lens 14 is generally made of acrylic resin.

Therefore, in this embodiment, a sufficient refractive index can be obtained by using, for example, an optical epoxy filler having a large refractive index as the filler 16. In other words, even though the filler 16 has a larger refractive index than the lens 14, and the lens 14 is thin and designed to have a large acceptance angle, total reflection occurs at the interface between the lens 14 and the filler 16. is unlikely to occur. Therefore, a sufficient light receiving angle can be obtained. In this case as well, the position of the light receiving element 11 can be set relatively arbitrarily. Moreover, there is an advantage that the light receiving element 11 and the lens 14' can be fixed with the filler 16.

[Effect 1 of the Invention] As described above, the present invention has a specific invention in which the light-receiving element is housed in the shield case as described above, so that the influence of noise on the light-receiving part can be reduced, and the signal can be transmitted to the light-receiving element. Since a recess is formed on the surface of the lens on the light-receiving element side through which light enters, the refractive index of the lens can be increased even if the lens is thin, and there is an advantage that the light-receiving angle can be widened.

In addition, in the related invention, since a filler with a high refractive index is filled between the light receiving element and the lens, total reflection is less likely to occur at the interface between the lens and the filler, which has the advantage of widening the light receiving angle. be.

[Brief explanation of the drawing]

Figure 1 is a sectional view of the main part of an embodiment of the specified invention, PlfJ
Figure 2 is an explanatory diagram showing the optical characteristics of the same lens, and Figure 3 is a schematic configuration diagram of a remote monitoring and control system in which the same lens is used.
Fig. 4 is a block diagram of the transmitter/receiver of the remote monitoring and control system as described above, and Fig. 5 is a block diagram of the transmitter/receiver of the same as above.
Fig. 6 is a signal waveform diagram of the same as above, Fig. 7 is a 7-ohm diagram of the same transmission code as above, Fig. 8 is a sectional view of the main part of an embodiment of the related invention, and Fig. 9 is a perspective view of the main part of the conventional example. , FIG. 10 is an explanatory diagram of the light receiving angle when the same as above is attached, and FIG. 11 is a sectional view of the main part of the same as above. A is a receiver, 11 is a light receiving element, 12 is a shield case,
14 and 14' are lenses, 14a is a recess, 15 is a light receiving window, and 16 is a filler. Agent Patent Attorney Ishi 1) Ai 7 Figure 4 Figure 5 - ~

Claims (2)

[Claims] (1) In a receiver for a spatial signal transmission device that uses light as a transmission medium, there is a light receiving element that is housed in a shield case to receive the signal light, and a light receiving element that is formed in the shield case to input the signal light into the light receiving element. 1. A receiver comprising: a lens disposed above a light-receiving window and having a recess formed on a surface facing the light-receiving element to increase the refractive index of the lens. (2) In a receiver for spatial signal transmission equipment that uses light as a transmission medium, there is a light receiving element that is housed in a shield case to receive the signal light, and a light receiving element that is formed in the shield case to input the signal light into the light receiving element. 1. A receiver comprising a lens disposed above a light-receiving window, and a filler having a large refractive index is filled between the light-receiving element and the lens.