JPS6234430A - Receiver for optical communication - Google Patents

Abstract

PURPOSE:To correctly receive signal light even when the titled receiver is used outdoors, by providing a light receiving angle control means which controls the light receiving angle of a light receiving means in accordance with manual operations. CONSTITUTION:A light shielding hood 105 composed of a pair of upper and lower components is provided at the outside of a light receiving lens 104. The light shielding hood 105 is frictionally held by a revolving shaft 113 by utilizing the frictional force of a friction washer 114 provided between the revolving base section 105b of the hood 105 and the head section 113a of the revolving shaft 113 fixed to the main body 6 of this receiver. When the light shielding hood 105 is manually operated by its operating end 105a, it can revolve around the revolving shaft 113 and its opened angle can optionally be set continuously without steps. Therefore, the influences of outside-of-periphery light can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical communication device that uses optical signals for signal transmission, and more particularly to a receiving device thereof.

Obedience! So far, optical communication devices have been known that use a light receiving element such as a photodiode as a light receiving means and receive an optical signal from a transmitting device by the light receiving element to enable information transmission and remote control of other devices. It is being

However, in the receiving device of such an optical communication device, especially when used outdoors, the intensity of external light such as sunlight is much higher than the intensity of the signal light. Therefore, S/
Therefore, it is an object of the present invention to provide a receiving VC device for optical communication that can accurately receive signal light even when used outdoors.

In order to achieve the above object, the present invention provides an optical communication receiver for receiving optical signals emitted from a remote location.
The apparatus is characterized in that it has a light receiving means for receiving an optical signal, and a light receiving angle control means for controlling the light receiving angle of the light receiving means in accordance with a manual operation.

Therefore, according to the present invention, the light reception angle control means is manually operated according to the relative position of the optical communication receiver and the transmitter, or according to the external light situation, and the signal light from the transmitter is accurately controlled. The task is to adjust the light-receiving angle characteristics of the light-receiving means so that the light can be received.

(Margin below) ×111 Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is a perspective view showing a camera system that transmits photometric information and controls operations using an optical communication device according to an embodiment of the present invention. In FIG. 1, (2) is a photographing lens. (4)
(6) is a receiver of an optical communication device that is electrically and mechanically connected to the camera body (2) as described later, and (8) is a receiver on the bottom surface of the camera body (2). A bracket (10) electrically and mechanically connected to the camera body (2) is an electronic flash device electrically connected to the camera body (2) via the bracket (8).

As shown in the front view of FIG. 2, the receiving WIC 6) includes a light receiving window (101) for receiving an optical signal from the transmitter shown in FIG. 3, a power switch (102), and a battery to be described later. A voltage drop warning light emitting diode (103) is provided which is turned off when the check circuit determines that the power supply voltage is insufficient. Furthermore, a pair of light receiving lenses (10
4) and a pair of upper and lower light shielding doors (105) that can be opened and closed are respectively arranged. The light-shielding door (105) has a pair of protrusions (105) for manual opening and closing.
) is of the form J&. (106) is a reception display window, and when a normal reception operation is performed, a reception display light emitting diode (107), which will be described later, placed inside the window will blink, indicating that a normal reception operation has been performed. The naked author controlling the transmitter is informed. Behind the pair of light receiving lenses (104) are light receiving elements (P D + ) (P D
z) is located.

Then, the receiving fi (6) has an upper part (6a) and a lower part (6b
) and 7 shoes provided at the bottom (6b))
(108) is attached to the camera body (2) by fitting into the seven-piece recess of the camera body (2), and this state is fixed by the fixing collar (109). In this state, the movable contact pin (110) formed on the shoe 7 [108] comes into contact with the fixed contact provided on the 7 shoe 7 of the camera body (2), and the receiver (6) and the camera The main body (2) is electrically connected. As a result, the camera body (2) receives exposure data and control data sent from the transmitter via the receiver (6), and necessary data from the bracket (8).
It is also transmitted to the electronic flash device (10) via.

The upper part (6a) of the receiver (6) can rotate relative to the lower part (6b) about the pongee (X) extending in the vertical direction in Fig. 2, and has a light receiving window (101) and a light receiving display. window(
106) can be changed.

The exposure data received by the receiver (6) is configured to be transmitted to the camera body (2) via a signal hood (1ii) connected to the input terminal (2a) of the camera body (2). Also, exposure data can be transmitted from the movable contact bin (110) and control data can be transmitted from the signal code (111).
The configuration may be such that the information is transmitted to the camera body (2), respectively.

FIG. 3 is a block diagram showing the electric circuit of this embodiment. In Fig. 3, (12) indicates a transmitter of an optical communication device that modulates the dinotal signal to be transmitted at several tens of KHz and transmits it as infrared light, and transmits fi (12).
A meter CM) and a transmitting circuit (12a) are provided inside. Here, the meter (M) is, for example,
As proposed by the applicant in No. 9-17897, the brightness of the subject and the amount of flash light are measured and stored using the incident light method, and an appropriate value is determined from the setting data such as film sensitivity, shutter speed, aperture value, etc. and the photometry results. It calculates the shutter speed and aperture value and outputs them as exposure data.

Then, this exposure data is converted into an infrared light signal by the transmission circuit (12a) and transmitted, and the reception 1+1 (6')
A light receiving element (P D , ) (P
D2).

('E) is the power supply battery for reception 1ff (6), (SW
, ) is the power switch of the receiving 1ff (6). When the power switch (SWI) is closed, the photodetector (PD
, )(P D 2) receives the infrared light signal from the transmitter fi (12) and outputs a current (a) according to its intensity. This output current (a) is input to an amplification and detection circuit (14), which amplifies and detects this output current (a) and outputs it as a data signal (b) to a subsequent data reading circuit (16). to communicate. Furthermore, this amplification detection circuit (14
) is the light receiving element (P D , ) (P D 2) of the receiving fi (6), regardless of the infrared light signal from the transmitter (12).
A warning signal (c) is output when the steady light component (hereinafter referred to as external light) incident on the light reaches a predetermined value or more in intensity.

For the detailed configuration of this amplification/detection circuit (14), see Section 4.
It is shown in the figure and will be described in detail later.

The data reading circuit (16) is a circuit that reads and checks the data signal (b) from the amplification/detection circuit (14), stores the data in order to transmit it to the camera body (2), and transfers the data. Yes, and includes an interface circuit for data transfer. Then, the data reading circuit (1
6) transfers the read exposure data to the camera body (2) via the movable contact bin (110) shown in FIG. Furthermore, the data reading circuit (16) includes an amplification detection circuit (
If the data signal (b) transmitted from 14) is correctly read, it outputs a signal (d) indicating that the signal transmitted by optical communication has been correctly read. From then on,
This signal (d) is called the verify signal by -1.

(18) is a timer circuit, which is a power switch (SW,
) is closed for a certain period of time, the timer signal (e) that is output is set to H”.
Along with the aforementioned verify signal (d), the NOR cycle M (NOR
, ), and the output signal (g) of this NOR circuit (NOR4) is further input to one input terminal of an AND circuit (A N D , ). The output signal (f) of the oscillator (20) is connected to the other input terminal of the AND circuit (A N D l).
is entered. Then, the output signal (g) of the NOR circuit (NOR3) and the output signal (h) of the 7.71 circuit (AND, ) are the output signal (h) of the 722171 circuit (22) (2
4) is input. These one-shot circuits (2
2) (24) are the input signals (g) and (h), respectively.
It is configured to output a pulse with a constant time width in response to the rising edge of .

Output signal (i) of both one-shot circuits (22) (24)
(j) both pass through an OR circuit (OR1) to a signal (k
) is input to the battery check circuit (26). The battery check circuit (26) checks the fi source voltage Vcc at a timing according to the input signal (k), and if the power source voltage Vcc is below a predetermined value, it latches it and outputs an output signal (+). Outputs the signal and lights up the voltage drop warning light emitting diode (BCLED). The operation of this battery check will be described in detail later.

The warning signal (e) of the amplification detection circuit (14), the verify signal (d) of the data reading circuit (16), and the timer signal (e) of the timer circuit (18) are each input to an OR circuit (ORI). . And OR circuit (ORI)
The output of is input to the display drive circuit (30) as a signal (■) via the delay circuit (28), and is input to the OR circuit (O
When any one input signal of RI) becomes "H", the display drive circuit (30) lights up the verification display light emitting diode (V L E D ') after a certain period of time determined by the delay circuit (28). be done. In other words, the verification eye display light emitting diode (VLED) outputs a timer signal (e) from the timer circuit (18) when the intensity of the external light exceeds a predetermined value and when the data is accurately read. For example, it is turned on by the output signal (n) of the display drive circuit (30).

Further, when the output of the OR circuit (OR+) becomes L'', the verify display light emitting diode (VLED) is turned off by the display drive circuit (30) after a certain period of time determined by the delay circuit (28).

In addition, Fig. 4 shows the detailed configuration of the amplification/detection circuit (14) of this embodiment.
are connected in parallel with each other, and the output signal (a) is taken out from the 7th node side.
7 nodes of PD2) are grounded via an inductance (L, ) and a resistor (R1). Furthermore, the output signal (a) is input to the amplifier (32) via the capacitor (C1), and the output signal (a) is amplified by the amplifier (32). This amplified signal is sent to the detection circuit (3
4) One signal is input, and the detection circuit (34) generates several tens of kilograms.
The signal modulated to Hz is detected, demodulated to the original digital signal, and transmitted to the subsequent waveform shaping circuit (36). The waveform shaping circuit (36) shapes the waveform of the input signal to be suitable for the subsequent data reading circuit (16), and outputs it as a data signal (b).

The inductance (L,) is connected in series with the resistor (R1), and the connection point is the comparator (CON,)
is connected to the non-inverting input terminal of On the other hand, the comparator (
A reference voltage fi (Vref, ) that generates a reference voltage is connected to the inverting input terminal of CON, ). and,
The output of the comparator (CON, ) is the warning signal (
c) as well as a transistor (Tr,
) is also input to the base. This transistor (Tr,
) is connected to the detection circuit (34) via the resistor (R1).
and the emitter is grounded. Furthermore,
The detection circuit (34) is grounded via a resistor (R2). Here, the transistor (Tri) is used as a switch, and is conductive when the output signal of the comparator (CONI) is I]'', and is non-conductive when it is 'L''.

The operation of the amplification/detection circuit having such a configuration will be explained. First, when external light unrelated to the signal to be transmitted enters the photodetector (p I), ) (P D 2),
A photocurrent is generated that is proportional to the intensity of the ambient light.

Such a charging current has a direct tIL component or 60Hz×
2 (or 50 Hz x 2), the impedance in the direction of the inductance (L+) is low, and the input impedance in the direction of the capacitor (C6) is a DC component or a low frequency component of 60 Hz (or 50 Hz) x 2. Since the frequency component has a high impedance, the above photocurrent has an inductance (Ll
) flows in the direction of the rising resistance (R, ). And the resistance (
A voltage corresponding to the photocurrent is generated across R3). This voltage is detected by the comparator (CONI) as the reference voltage -@(V
When the voltage across the resistor (R1) is lower than the reference voltage, the intensity of the peripheral light component is low and the photocurrent generated in the light receiving element (P D +) (p D , ) is compared with the reference voltage of re41). Since the output of the comparator (CON, ) is low, the warning signal (c) is not generated. Therefore, in this case the transistor (T r, )
becomes non-conductive, the current flowing from the detection circuit (34) to the ground is kept small by the resistor (R2), and its detection sensitivity is set high. That is, when there are few external light components and the charging current generated in the light receiving element (p DI) (P D 2) is small, the sensitivity of the detection circuit (34) is set high.

In this state, several tens of KHz from the transmitting fi (12)
The infrared light signal modulated into the photodetector (PD, ) (PD2
), the light receiving element (P D t) (p D 2
) generates a photocurrent due to the external light component and a charging current due to the infrared light signal. However, the inductance (Ll) has a high impedance to AC components, while the impedance of the capacitor (C,) decreases, so the AC component of the output photocurrent of the photodetector (P D , ) (P D 2) decreases. The component, that is, the charging current component due to the infrared light signal component is input to the amplifier (32) via the capacitor (C1) and amplified. Then, the DC component, that is, the charging current component due to external light, is cut by the capacitor (cl), so it flows toward the inductance (L,) and the resistance (R,)! The signal amplified by the amplifier (32) is
The detection circuit (34) is set to high sensitivity as described above.
The signal is input to and detected by the waveform shaping circuit (36), and the waveform is shaped by the waveform shaping circuit (36) and outputted as a data signal (b) to the data reading circuit (16).

Conversely, the light receiving element (P D , ) (P
If the output charging current component of D2) is large and the voltage across the resistor (R,) is larger than the reference voltage, the humpator (C
ON, ) output becomes "l("), a warning signal (C) is issued, and the light emitting diode (VLED) for verify eye display
is illuminated to warn the user that external light may interfere with accurate signal transmission. Furthermore, when the output of the comparator (CON, ) becomes H", the transistor (Tr, ) becomes conductive, and the detection circuit (34) is grounded through the resistor (R3) in addition to the resistor (R2), and the detection circuit (34) ) to ground increases, so its sensitivity decreases.

This is to remove the well-known effects of shot noise and fluorescent lighting. In other words, the intensity of shot noise is approximately proportional to the square root of the brightness of the external light, and when the external light is strong,
The shot noise mentioned above may be mistaken for a signal component, and the pulsed light from a fluorescent lamp may be mistaken for a signal component. If the external light component is strong, the detection circuit (34
) to prevent these noises from being transmitted as signals.

Here, in order to prevent the output of the comparator (CON,) from repeating "H""L" due to the illumination of the AC light source, it is necessary to provide hysteresis to the comparator (C0N,). However, since it is not directly related to the present invention, its explanation will be omitted.

That is, to summarize the functions and operations of each electric element in the circuit shown in Figure 4, first, the capacitor (C1) cuts the DC component, and the inductance (Ll) and resistance (R, The photocurrent due to the component is transferred to a capacitor (C
1), and serves to cause the photocurrent due to the peripheral light component to flow in the direction of the inductance (Ll). Furthermore, the comparator (CON, ) has a resistance (CON, ) according to the intensity of the peripheral light component.
The voltage across R2) is compared with a reference voltage to determine whether the intensity of the peripheral light is equal to or higher than a predetermined value. Here, since the inductance (L,) has almost no DC resistance value, by reducing the resistance value of the resistor (R5), the light receiving element (
It is possible to improve the load characteristics when a load resistor is connected to PD, ) (PD2). In other words, it is possible to accurately receive optical signals without the circuit becoming saturated even under high illuminance. However, if the illuminance becomes too high, noise due to the external light component will be transmitted to the data reading circuit (16) as the data signal (b), so in this embodiment, the detection sensitivity is adjusted according to the judgment result by the comparator (CON). control to prevent noise from being transmitted to the data reading circuit (16);
Display is performed when the peripheral light component is strong.

The Is diagram is a circuit diagram showing a modification of the amplification/detection circuit of FIG. 4. In the configuration shown in Fig. 4, the sensitivity of the detection circuit (34) was switched according to the determination result of the comparator (CON, ), but in this modification, the sensitivity of the detection circuit (34) is changed depending on the judgment result of the comparator (CON,
The amplification degree of the amplifier (32) is adjusted according to the determination result. The difference between the configuration shown in FIG. 5 and the configuration shown in FIG. 4 is that the amplifier (32) is grounded via a resistor (R1) and a capacitor (C2). Then, the relationship between non-inverting input and inverting input is opposite to that in Figure 4.
<The output of the regulator (CONl) is a transistor (Tr) whose collector and emitter are connected in series to a resistor (R6) connected between the amplifier (32) and the capacitor (C2).
2) is connected to the base. Therefore, the amplifier (32
) is determined by the resistance (R5) (R, ).

In other words, when the outer light component is small and the resulting photocurrent is small, the output of the comparator (CON, ) is H''
And since the transistor (Tr2) is conducting,
The amplification degree of the amplifier (32) is determined by both the resistors (R2) and (R6), and is set to a high amplification degree. When the outer light component is large and the resulting photocurrent is higher than the reference voltage, the output of the comparator (CON, ) becomes L'' and the transistor (Tr2) is made non-conductive, so that the amplifier (32) The amplification degree is determined only by the resistor (R6) and is set to a lower amplification degree.Therefore, according to this modification, by lowering the amplification degree of the amplifier (32) when the external light component is strong, This prevents noise from being transmitted to the data reading circuit (16) as the data signal (b).In this modification, the output of the comparator (CON) is input to the inverter (IV), The output of this inverter (IV) is a warning signal (
Used as e).

Furthermore, FIG. 6 is a circuit diagram showing another modification of the amplification/detection circuit shown in FIG. 4. In this modification, the detection circuit (34)
The sensitivity of the camera is configured to be switched between three levels. In this modification, inductance (L, ) and resistance (R5
) is connected to the non-inverting input terminal of the second comparator (CON 2). A second reference power source (Vref2) that generates a reference voltage higher than the reference power source (Vref+) is connected to the inverting input terminal. The output of this comparator (CON 2) is output from a resistor (
It is connected to the base of a transistor (Tr3) whose collector and emitter are connected in series to R7).

With such a configuration, if the voltage across the resistor (R1) depending on the intensity of the external light component is sufficiently low, the Conhalley 9
(CON 1) (CON 2) ) Knee b I:
+ Output 1. t″L″, therefore, both the transistors (Tr, ) (Tr-) are non-conductive, so the sensitivity of the detection circuit (34) is determined only by the resistor (R2) and has the highest sensitivity. When the voltage across the resistor (R1) becomes a little higher than that, the reference power supply (Vrer
Since the reference voltage of i is lower than the reference voltage of the reference power supply (Vref2), only the output of the comparator (CON, ) becomes I('', and only the transistor (Tr, ) conducts and the resistor (R2) A resistor (R1) is connected in parallel.Therefore, in this case, the sensitivity of the detection circuit (34) is reduced by one step.Furthermore, the extraneous light component becomes even stronger (and the resistor (R1)
3) When the voltage across the terminal becomes higher, the humperator (CO
Since the outputs of both N, ) (CON2) become H" and both transistors (Tr+) and (Trz) become conductive, the resistance (R
A resistor (R1) and a resistor (R7) are connected in parallel to 2), and the sensitivity of the detection circuit (34) is further reduced to the second stage. In this way, according to this modification, the detection circuit (3
The sensitivity of 4) can be changed in three stages. still,
In this modification, the output of the comparator (CON z) is used as the warning signal (e).

If it is necessary to change the sensitivity of the detection circuit in four or more stages, the number of resistors, transistors, comparators, and reference power supplies may be increased in the same way. Further, as in the modification shown in FIG. 5, the degree of amplification of amplification "1" (32) can be easily changed in three or more stages depending on the intensity of the outer light component.

Figure 7 shows a circuit configuration in which the load characteristics of the photodiodes constituting the light receiving elements (P D 1) (P D 2) can be used even in bright areas, so that signals can be read without the circuit becoming saturated. In such a case, the input terminal of the amplifier (32) is connected to the connection point between the photodetector (PCI) (P D 2> and the inductance (Ll) via the capacitor (C1). In case l
±, DC components of the output charging currents of the light receiving elements (P D 1) (P D2) are removed by the capacitor (C1), and the DC components are input to the amplifier (32) and amplified.
), only the signal is detected by the waveform shaping circuit (36).
The output waveform is shaped by However, in this precept, the display based on the intensity of the peripheral light component as described above,
Sensitivity switching of the detection circuit (34) and amplifier (32)
) cannot be switched.

FIG. 8 is a circuit diagram showing yet another modification of the amplification/detection circuit shown in FIG. OR circuit (IC,) connected to the output of
is connected to the other input terminal of

With this configuration, when the intensity of the external light component is low, the output of the comparator (CON, ) remains at L'', so the waveform shaping circuit (36
) is output as is, and the data reading circuit (
16). On the other hand, when the intensity of the outer light component is large, the output of the humpator (CON, ) becomes H'', and the output of the OR circuit (IC, ) becomes H'', and the output of the OR circuit (IC, ) becomes H''.
It remains I-bi regardless of the output. That is, when the external light component is large, the signal from the waveform shaping circuit (36) is not input to the data reading circuit (16) and is fixed at 'H'. With this configuration, the noise due to the external light component will not be transmitted to the data reading circuit (16), and the malfunction of transmitting an erroneous signal as the data signal (b) to the data reading circuit (1G) will not occur.

FIG. 9 is a circuit diagram showing another modification example in which only the DC component corresponding to t1' is selected for the peripheral light component of the photocurrent of the light receiving element (PD, ) (PD, ). In order to extract only the DC component of the photocurrent of the photodetector (P D ,) (P D 2), a resistor (Ra) and a capacitor (
A smoothing circuit consisting of Ca) is used. and,
The time constant of this smoothing circuit is set so that the AC component of about 60 Hz, such as from fluorescent lamps, is extracted from the connection point between the resistor (Ra) and the capacitor (Ca).6Then, depending on the output of this connection point, If the intensity of the external light is fixed by f1, only the external light component can be extracted with a simple configuration.

Next, the operation of the battery check system shown in FIG. 3 will be explained using the time chart shown in FIG. 10. In FIG. 10, (1) shows the operation when the voltage of the power source battery (E) is sufficient. First, at time t. When the power switch t' (S W I) is closed, the timer circuit (18) outputs a timer signal (
e) is issued. Also, a signal ([) is emitted from the oscillator (20) by closing the power switch (SW, ).
In this case, the warning signal (e) of the amplification detection circuit (14)
and data reading circuit (16) slope 7 eye signal (d)
Neither is emitted, and both outputs are up to the quintillion of "L". Then, an OR circuit (
The output of OR1) becomes H”, and therefore the off-circuit (OR,
) becomes I]'', the output signal (m) of the delay circuit (28) becomes l('' with a delay of .).Furthermore, the output signal (-) of this delay circuit (28) The display drive circuit (30) is driven, and its output signal (n) becomes "H" and the light emitting diode (VL) for verification display is driven.
ED) is lit. Here, the timer signal (e)
becomes *Hs, so the output signal (g) of the NOR circuit (NOR, ) becomes "L", and therefore the output signal (f) of the oscillator (20) becomes the output (1+) of the AND circuit (AND, ). It does not appear.

At time t1, when the timer signal (e) of the timer circuit (18) becomes "L", the NOR circuit (NOR,)
The output signal (g) is inverted to "H", and a short pulse signal (i) is generated from the one-shot circuit (22). This pulse signal) is passed through an OR circuit (OR, ) to a signal (k
) is input to the battery check circuit (26).

Then, the battery check circuit (26) checks the voltage V of the power supply battery (E) at a timing corresponding to this input pulse (k).
cc is checked, and the power supply voltage VCC is Vrc in Figure 10.
It is determined whether t is greater than or equal to a predetermined value indicated by f3. While this battery check is being performed, the delay circuit (
The output signal (m) of 28) takes a time τ from the output of the OR circuit (OR+). Since the delay is "I("), the verify indicator light emitting diode (VLED) continues to be lit.

Then, when a certain period of time T determined by the timer circuit (18) has elapsed from time t0, the timer signal (
e) becomes "L". Then, the output signal (g) of the 77 circuit (NOR1) is inverted to "H", so the AND circuit (A
A signal synchronized with the oscillation signal (") of the oscillator (20) is output from the AND circuit (AND, ) and inputted as a signal (h) to the 722171 circuit (24).

Therefore, the one-shot circuit (24) outputs a short pulse signal (j) every time the signal (h) rises.

The period of this pulse signal (j) is determined by the oscillator (20)
It is synchronized with the oscillation signal of

This pulse signal (j) is inputted to the battery check circuit (26) as a signal (k) through an OR circuit (OR1), and 'I' is input at a timing corresponding to this pulse signal (k).
The IL source voltage Vcc is checked.

During the time T2 from time t2 to t in FIG. 10 and the time T2 from time t to t5 in FIG. (14) is amplified and detected,
The state of each signal when read by the data reading circuit (1-6) is shown. In this case, the timer circuit (
The timer signal (e) of 18) remains at "L", and since the extra-frequency light component is small, the warning signal (c) from the amplification/detection circuit (14) also remains at "L".

When the data reading circuit (16) accurately reads the transmitted data, a verification signal (d) of "H" is generated for a certain period of time T2. This verify signal (d)
Therefore, the output of the OR circuit (OR,) is "H" for a certain period of time T2, and therefore, the output from the delay circuit (28) is
. After a delay, an H'' signal (-) is output for a time T2.

The display drive circuit (30) is driven by this H'' signal (gull) and outputs an H'' signal (n) for a certain period of time T2.
) is lit for a time T2. Furthermore, the H'' Veri7F signal (d) inverts the output signal (g) of the 77 circuit (NOR, ) to 'L'', so one input of the AND circuit (AND, ) becomes "L". , AND circuit (A N D
, ) remains at "L". Therefore, the output signal m of the oscillator (2o) is generated by an AND circuit (AND,
) no longer appears in the output signal (h). Therefore, while reading data, which input (
i) Since (j) also remains at L'', no battery check operation is performed during this time.

Then, when the verify signal (d) of the data reading circuit (16) changes to "L" at time t or t, the output signal (i) of the one-shot circuit (22) shortens as at time t1. A pulse signal appears, and the W1 source voltage Vcc is checked by the battery check circuit (26) in accordance with the timing of this pulse.

At this time, the verify signal (d) is inverted by the delay circuit (28) for a time τ. The display drive circuit (30
), the verify eye display light emitting diode (V L ED ) is lit.

Next, the operation from time t6 to t7 in FIG. 10 will be explained. This is an operation when the intensity of the external light is high. First, when the amplification and detection circuit (14) determines that the intensity of the external light is equal to or higher than a predetermined value, it outputs "H" as a warning signal (c). As a result, the output of the OR circuit (OR, ) becomes H'', and a time τ has elapsed since the alarm signal (c) went up.

Light-emitting diode for 7-eye display (V L
E D ) is lit to warn the user that the intensity of the ambient light is high.

In this case, the timer signal (
e) is "L", and the data reading circuit (16) is 7
The eye signal (d) is also "L". Therefore, the NOR circuit (N
The output signal (g) of OR, ) becomes “H” and the OR circuit (
The output signal (k) of OR2) is a short pulse in response to the oscillation signal (') of the oscillator (2o).

This causes the battery check circuit (26) to
Check the source voltage Vcc periodically.

Here, the timing pulse (signal (k)) for activating the battery check circuit (26) is timed. The reason why it is not emitted during gar [, t2 to t, and t, gar L5, but is emitted only at other times is as follows. First, time 1. The period tl is immediately after the power switch (S w + ) is closed,
The verification display light emitting diode (VLED) is turned on for a certain period of time T after the power switch (SW, ) is closed, and during that time, the voltage drop warning light emitting diode (BCLED) is turned on to eliminate confusion in the display. This is to prevent the light from turning on. Then, from time t2 and from t4 to t5, if a battery check is performed during this period and it is determined that the power supply voltage Vcc is below the predetermined value Vref3, the output signal of the battery check circuit (26) ( "H" is input from o) to the data reading circuit (16), thereby inverting the verification 7 eye signal (d) to "I", turning off the verification display light emitting diode (VLED), and starting the operation. Since the NII is configured to stop, the light emitting diode for verification display (V
This is because the lighting time of the LED) becomes shorter and does not reach the fixed time T2. Therefore, in this embodiment, the battery check operation is not performed during the above three times.

Furthermore, in the receiver of such an optical communication device, the light emitting display needs to be visible from a far away position, and therefore the display light emitting diode is driven with a very large current. Therefore, the voltage drop warning light emitting diode (BCLED) is also installed in the verification display light emitting diode (VLED). ``Since it is undesirable to turn on the factory lights, the system is configured so that Saturday pantry checks are not performed from time L0 to Ll, from t2 to 1, and from 14 to t.

However, the time. +τ. From L1+τ. , t2+τoh
・Light-emitting diode for verification display of Rari, +τo1 and Rari, +τ0 to t, +τ0 (V L E D )
During lighting, this light emitting diode (V L E
τ of the light-emitting diode (VLED) being turned off, since the power supply voltage Vcc is considered to be the lowest just before the light-emitting diode (VLED) is turned off. In other words, at times t1, t5, and E, a battery check is performed to check whether the power supply voltage can be stably supplied from then on.

(2) in the time chart of FIG. 10 is the power supply voltage Vcc.
This shows the operation when Vref3 falls below the predetermined value Vref3. Battery/battery check circuit (26) is off [il
The power supply voltage Vec is checked according to the output pulse (k) from u (OR2), and if it is determined that the power supply voltage Vcc has become equal to or less than the predetermined value V-ref3 at time L6, the output (
1) Output "11" from each (o). This causes the voltage drop warning light emitting diode (BCL E
D) is turned on to display a decrease in the voltage, and at the same time, the operation of the data reading circuit (16) is stopped. And the battery check circuit (2
6), once the power supply voltage Vcc becomes less than the predetermined value Vref-, the outputs (1) and (0) remain in the "H" state even if the power supply voltage Vcc becomes equal to or more than the predetermined value Vrefs. This is done by opening the switch (SW, ).

Furthermore, (3) in the time chart of the PtSi2 diagram shows that the power switch (SWI) is closed and the timer circuit (18) is closed.
is in operation, the power supply voltage Vcc reaches the predetermined value Vref=
This shows the behavior when the value drops below. Here, as mentioned above, time 1. when the timer signal (e) of the timer circuit (18) is "H". Karari. During the time period T, the battery check is not performed and the timer signal (e) is low.
``'', the battery check circuit (26) is activated for the first time at time E1, and it is determined that the power supply voltage Vcc is below the predetermined value Vrefs, and the voltage drop warning light emitting diode (BCLED) is turned on. It will be done.

Furthermore, in (4) of the time chart, the power supply battery (E) is exhausted, and the battery voltage E decreases due to circuit operation and light emitting diode drive before the power supply off switch (SW, ) 17 (achievement point Ll+). The limit voltage of ■. indicates the operation when the voltage is lower than
Even if WI) is closed, both sales light guider-)(VLED)(B
CLED) and f: are not lit, so a drop in the voltage of the power supply battery (E) is immediately indicated. Here, as is clear from comparing (1) and (4) in the time chart, (1
) in the normal state, after the power switch (SW, ) is closed, the light emitting diode (
If the battery voltage drop (VLED) is not turned on, it will not be possible to display a display that is distinct from the case when the battery voltage drops (4). Therefore, in this embodiment, the verification display light emitting diode (VLED) is turned on for a certain period of time T1 in the normal state. It is.

(5) in the time chart indicates that the data reading circuit (16) accurately reads the transmitted data, and thereby "■4
This shows the operation when the power supply voltage Vcc becomes equal to or less than the predetermined value Vref3 while the verification signal (d) of `` is output and the 7-eye display tear light emitting diode (VLED) is lit. In this case, the battery check circuit (26) is activated by the battery check timing pulse (k) at t14 when the verify eye display light emitting diode (VLED) is turned off as described above, and the power supply voltage Vcc is checked. The voltage drop is determined and the voltage drop warning light emitting diode (
BCLED) is lit 7α to warn of a drop in power supply voltage.

Next, the internal NII structure of the receiver (6) shown in FIG. 1 will be explained. First, FIGS. 11(a) and 11(b) are cross sections B in FIG. 1. In FIGS. 11(a) and 11(b), inside the light receiving window (101) is a pair of light receiving lenses (104),
A pair of band pass filters (112) and a light receiving element (
PDIOPD2) are arranged in order from the outside world. Further, a pair of upper and lower light shielding doors (105) are provided on the outside side of the light receiving lens (1"04).
Figure 11 (a) shows the case where the opening angle of the light shielding hood (105) is increased, and Figure 11 (b) shows the case where the opening angle of the light shielding hood (105) is decreased. ) and the element chip () in the photodetector (PD, ) (PD2)
The relationship with incident light directed toward PDa) is shown.

FIG. 12 is a perspective view showing the structure of the pair of light shielding doors (105) and their rotating wheels (113).

The light shielding 7-door (105) has a rotating base (105b) and a rotating shaft (113) fixed to the receiver body (6).
) is frictionally held in rotation @ (113) by the friction force of the friction washer + (1t4) sandwiched between the rIri portion (113a) and the rIri portion (113a). The light shielding 7-door (105) can be rotated around the two rotation axes (113) by manually performing operation 1 (105a), and the state shown in FIG. 11 (a) or ( In the state b), the opening angle can be set individually and continuously as desired.

FIG.

In Figure 1513, the curve (A) is the WI! The curve (B') shows the characteristics when the opening angle of the light shielding door (105) is made small as shown in FIG. 11(b).

The light-shielding hood (105) is usually as shown in tjfJ11 (a)
It is used at the maximum opening angle shown in the figure. In this case, it is possible to capture a luminous flux incident within a range of an incident angle of 0 or less from the optical axis on the entire surface of the element chip (PDa). 20) The specific sensitivity characteristic of the light receiving part is shown in the t513 diagram for song #1t.
The width is shown in (A). On the other hand, when there is an extremely large amount of external light, that is, when the brightness of the background of the transmitter is extremely high, the receiver cannot receive signals normally. In this case f5
It is effective to reduce the opening angle of the light shielding door (105) as shown in FIG. 11(b). In this state, only the light beam incident almost parallel to the optical axis is transmitted to the element chip (PDa).
) can receive light over the entire surface, and no light beam with an incident angle of β or more reaches the element chip (PDa). In this case, the specific sensitivity characteristic of the light receiving section becomes narrow as shown by curve (B) in FIG. Comparing curve (A) and track #1l (B), both curves have almost the same specific sensitivity on the optical axis (θ=0), and the area surrounded by the curve and the horizontal axis is equal to curve CB.
) is a fraction of that of song M(A). Therefore, when the external light is strong, the light shielding 7-board (105) is operated to the state shown in FIG. 11(b) so as to obtain the specific sensitivity characteristic represented by song #1(B), ) If communication is performed by installing the transmitter fjl (12) on the optical axis of In addition, it is possible to achieve normal reception in the state shown in FIG. 11(a).

Furthermore, since the two light shielding doors (105) can be adjusted to open and close independently, it is also possible to set the center of the aperture created by the two light shielding doors at a position offset from the optical axis. . Therefore, it is also possible to set the specific sensitivity characteristic as shown by curve (B) in FIG. 13 with the center shifted from the optical axis.

FIGS. 14(a) and 14(b) respectively show cross section A in FIG. 1. In FIGS. 14(a) and (b), the reception display window (
A verify display light emitting diode (VLED') is housed inside the 10G). Figure 14 (
a) shows a reverse trace of the light rays reflected on the external side surface of the reception display window (106) when viewed from a distance on its optical axis. Further, FIG. 14(b) shows a reverse trace of the light ray when the receiving display window (ioe) is viewed from a distance shifted by a certain angle from the optical axis. Also, t51
Figure 5 shows the spectral transmittance characteristics (C) for the wavelength of the reception display window (106) and the light emitting diode (
Relative intensity characteristics (D
) are shown superimposed on each other.

Regarding the reflected light at the outer surface (106a) of the reception display window (106), as shown in FIGS. 14(a) and (b),
All the light that reaches the eye is transmitted to the pit wall (6c) of the receiver body (6).
). Therefore, the reception display window (1
06), the hole g section (6c) of the receiver body is reflected on its surface (106a). This pit wall portion (6c) is painted black or the like to have a low reflectance. Therefore, with this configuration, direct reflected light from the outside world does not appear reflected on the outer surface (106a) of the reception display window (10G), and a surface with low reflectance appears reflected. It is possible to keep the brightness of the surface of the display window (10G) low.Also, the light emitting diode side surface (106b) of the reception display window (106) can also be kept at the outer surface (10G).
It has exactly the same effect as 06b). With this configuration, it is possible to reduce the brightness of external light reflected by the reception display window (106) when viewed from the outside world, so that when the internal 7-eye display light emitting diode (VLED) is turned on, the outside world It is possible to increase the S/N ratio of brightness when viewed from above, making it easier for an observer to confirm blinking.

In addition, as shown by curve (C) in Fig. 15, the reception display window (106) transmits most of the light emitted by the verification eye display light emitting diode (VLED) in the visible range, and transmits light in other bands. Made of absorbent material. Therefore, the majority of external light that illuminates the chip surface (cb) and reflective surface (p) of the light emitting diode (VLED) is blocked by the receiving display window (106).On the other hand, the light emitting diode (vt Most of the light emitted from the receiver display window (106) can pass through the receiver display window (106) and exit to the outside world.
The spectral transmittance characteristics of the light-emitting diode for verification display (v t, ED ) can also increase the S/N ratio of the brightness seen from the outside when the internal verification display light emitting diode (v t, ED ) blinks, making it easier for observers to confirm the blinking. becomes easier.

As described in detail above, according to this embodiment, when there is a possibility that accurate data communication using the signal light is not possible due to the strong intensity of the external light, the verification display light emitting diode (
As a warning is issued by lighting up the VLED, the user can take measures such as changing the direction of the receiving FI (6) to ensure accurate data communication, and prevent malfunctions due to inaccurate information transmission. can be prevented from occurring. Furthermore, if the strength of the external force is strong, the amplification detection circuit (14)
By lowering the sensitivity of the sensor, the possibility of malfunction due to external light can be reduced. Furthermore, according to this embodiment, when the power supply voltage is sufficient, the light emitting diode for verify eye display (
V L E D ) is turned on, and if the power supply voltage has slightly decreased, the eye display light emitting diode (VLED) and the voltage drop warning light emitting diode (BCLED) are turned on. , when the power supply voltage is very low, the surface-emitting diode (V
Since neither L E D ) (B CLED) is turned on, three types of states can be distinguished and displayed using the two display elements. Further, according to this embodiment, the amplification/detection circuit (14) can separate the light 7ri current corresponding to the extra-frequency light component and the photocurrent corresponding to the signal component, and the above-mentioned process can be performed according to the extra-frequency light component. Since the display and sensitivity can be switched, accurate optical communication can be performed even in places where the external light component is strong, such as outdoors.

In addition, in this embodiment, a light receiving element (P
D1) (PD2) is configured to detect the extra-local light component from the output, but the present invention is not limited to this, and a light-receiving element may be provided separately for detecting extra-local light; however, If it is also used as a light receiving element for IBO signal reception as in this embodiment, the configuration can be simplified.

FIG. 16 is a circuit diagram showing a main part of another embodiment of the present invention in which one of the photodiodes (P D , ) (P D 2) is selected and used depending on the temperature. In Figure 16, the voltage (Vcc) from the 'ti battery (E) is
An analog switch (s
W2) (S W2) are connected to each other. And,
The inverting input terminal of the comparator (CON, ) is connected to a temperature detection circuit (TD) that detects the temperature, converts it into a voltage proportional to the detected temperature, and outputs the voltage. On the other hand, the non-inverting input terminal of the comparator (CON3) is connected to a reference power source (Vref-) that generates a reference voltage with ground as a reference. The output of the comparator (CON) is connected to the date of the analog switch (SW z ), and is also connected to the date of the analog switch (SW, ) via the inverter circuit (Ice). 7 of the element (r' D ,) (P D ,)
The node is connected to the amplification/detection circuit (14) shown in FIG. 3 as output No. 3 (a). Here, in FIG. 17, the spectral sensitivity characteristics of the light receiving elements (P D , ) (P D , ) are shown as curves (K) and (F'), respectively.

Next, the operation of this embodiment will be explained. First, in devices that perform remote communication using optical signals, it is best to match the spectral sensitivity of the light-receiving element on the receiver side with the spectral sensitivity of the light-emitting diode on the transmitter side. As shown in FIG. 18, the emission peak wave pressure shifts from (G) to (H)CI) toward longer wavelengths as the temperature rises.

Therefore, at low temperature, the photodetector 7-(p D +)(p D 2
) have the same spectral sensitivity and match the spectral sensitivity characteristics of the light emitting diode (PD), the light receiving element (PD, )
Among the photocurrents generated by (PD2), those due to signals become small, and only a large photocurrent due to external light is generated, resulting in a poor S/N ratio. Therefore, in this embodiment, two photodetectors (PD, ) (PD2) having different spectral sensitivities as shown in FIG. 17 are provided, and at low temperatures, the output of the photodetector (PD, ) is used. By configuring the device to use the output of the photodetector (PD) when the temperature reaches high temperatures, it is possible to operate with a low S/N ratio of 1 at both low and high temperatures.

Here, the temperature detection circuit (TD) used in this example
is configured to detect temperature and output a voltage proportional to the temperature. That is, when the temperature is low, the voltage output by the temperature detection circuit (TD) is small, and when the temperature is high, the voltage output is large. Therefore, when the output voltage of the temperature detection circuit (TI) is lower than the voltage from the reference power supply (VreL), that is, when the temperature is low, the output of the comparator (CON 3) becomes "I". Then, this “+(” signal enters the date of the analog switch/chi (SW2), so the analog switch (SW 2 ) becomes conductive, and the 17th
Photodetector T with spectral sensitivity characteristics shown by curve (K) in the figure
The output of (PD,) is adopted. Further, at this time, the output of the inverter circuit (Ice) becomes L'', so the analog switch (SW3) is in a non-conducting state.

And as the temperature rises, the temperature detection circuit (TD)
The voltage output by increases, and the reference? [i%2(
VrcL), the output of the comparator (CON) becomes L'' (when the temperature rises).
becomes. Then, this signal causes the analog switch (S
W2) becomes non-conductive, while the inverter circuit (I
Since the output of C, ) becomes “H”, the analog switch (S
When an "H" signal is input to the date of W3), the analog switch (SW3) becomes conductive, and the output of the photodetector (PD2) is adopted instead of the output of the photodetector (PD, ). .

In this way, two light receiving elements (P
D , ) (P D 2), at low temperatures a light receiving element (FDP) with spectral sensitivity similar to the light emitting characteristics of a light emitting diode at low temperatures is adopted, and at high temperatures the light emitting characteristics of a light emitting diode at high temperatures are used. By adopting the output of the photodetector (PD2) with similar spectral sensitivities, the spectral characteristics of the photodetector and light emitting diode can be matched to each other at both low and high temperatures, further improving the S/N ratio. You can do it.

Note that the spectral sensitivity characteristics of the light receiving element (P D +) (P D 2) only need to be similar to the spectral characteristics of the light emitting diode, and do not have to be as shown in FIG. 17.

Further, FIG. Pt519 is a circuit diagram showing a modification of the embodiment of FIG. 16. The modified example shown in the Pt519 diagram shows a configuration in which three light receiving elements (with three spectral sensitivities) are provided and one of them is adopted depending on the temperature. FIG. 20 is a graph showing the spectral sensitivity characteristics of the f53 photodetector (PD, ) used in addition to the previous two photodetectors (PD, ) (PD2). Incidentally, here, it is also possible to use four or more light-receiving elements and selectively adopt the output of one of them depending on the temperature, but this can be easily considered from Figure 11 or Figure 19. I will omit the explanation here.

In FIG. 19, the temperature detection circuit (TD) is as shown in FIG. 16, and its output is input to the comparison and selection circuit (CS). Then, the comparison and selection circuit (CS
) is connected to the date of an analog switch (SW2) connected in series to the photodetector (PD, ), and the output (OUT 2) is connected to the photodetector (PD, ).
3) is connected in series to the analog switch (SW 3).
), and the output (OUT 3) is an analog switch connected in series to the photodetector 7- (PD2).
Connected to Nochi (SW, )'s date and 1. here,
The comparison selection circuit (CS) receives a voltage proportional to the temperature from the temperature detection circuit (TD), and when the voltage is small,
In other words, when the temperature is low, only the output (OUT,) (3) is set to H''. At this time, the output (OUT,) and the upper V(O
The signals of UT, ) are both L". Then, when the temperature rises a little and the input voltage of the comparison and selection circuit (CS) increases, only the output (OUT 2) No. 44 becomes H"EL.
Output (OUT,) t; , k I/(OUT,
) noise 1; both bows are set to °゛L''.Furthermore, when the temperature rises and the input voltage of the comparison and selection circuit (O3) further increases, the comparison and selection circuit (CS) changes the output (OUT, ). Set only the signal to "H".

Next, the operation of this modified example will be explained. Here, the details of the operation will be understood from the explanation of the embodiment shown in FIG. 16, and will be briefly explained here. Temperature detection circuit (
When the temperature detected by the comparison and selection circuit (CS) is low, only the signal of the output (OUT, ) of the comparison and selection circuit (CS) is “I(
”, and as a result, only the analog switch (SW, ) becomes conductive, and the output of the photodetector (PD, ) is adopted.Then, as the temperature rises, the light receiving When the temperature reaches a point where using the output of the device (FDP) provides a better S/N ratio, the comparison and selection circuit (C
8) sets only the output (OUT z) to "H" and uses the output of the light receiving element (PD, ). Furthermore, when the temperature rises to such a temperature that the S/N ratio is better if the output of the photodetector probe (PDz) is adopted than that of the photodetector (PD, ), the comparison and selection circuit (CS) outputs the output (OUT, ). ) is set to "H" and the output of the light receiving element (P D 2) is adopted.

By using a plurality of light-receiving elements having different spectral sensitivities in this way, the S/R ratio can be further improved than in the embodiment shown in FIG.
The N ratio can be improved.

In addition, here, the light receiving element (P D ,) (P D 2) (P
The spectral sensitivity characteristics of Dco) are shown in Figure 17 above [/'! 2't
The ridges do not have to be as shown in FIG. 20, and may be similar to the spectral characteristics of the light emitting diode.

As described in detail above, the present invention provides an optical receiver for receiving optical signals (i.e., δ) for receiving light (i.e., It is characterized by having a light receiving means and a light receiving angle control means for controlling the light receiving angle of the light receiving means in accordance with manual operation, and by configuring it in this way, a receiving device and a transmitting device for optical communication can be obtained. The light receiving angle control means can be manually operated according to the relative position of the receiver or according to the external light situation, and the light receiving angle characteristics of the light receiving stage can be adjusted so that the signal light from the transmitting device can be accurately received. Even when used outdoors, the signal light from the transmission Vcr!1 can be accurately received without being affected by external light.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing a camera system using an optical communication receiving device according to an embodiment of the present invention, Fig. 2 is a front view of the receiving device, Fig. 3 is a block diagram showing the electric circuit of the system, and Fig. 4 The figure is a circuit diagram showing the specific configuration of the amplification/detection circuit, Figures m5 to 9 are circuit diagrams showing modified examples of the amplification/detection circuit, and Figure f510 is a time chart showing the operation of the system in Figure 3. , Pt1111 is a cross-sectional view of B in FIG. 1, FIG. 12 is a perspective view showing the configuration of the light shielding 7-door, and FIG. 13 is a graph showing changes in the specific sensitivity of the light receiving element due to opening and closing of the light-shielding 7-door. , FIG. 14 is a cross-sectional view of A in FIG. 1, FIG. Figure 17 is a graph showing the spectral sensitivity characteristics of the light receiving element, Figure 18 is a graph showing changes in the light emitting characteristics of the light emitting diode due to temperature, and Figure 19 is fj.
SL (a circuit diagram showing a modification of Fig. 3, tJS20 is a graph showing the spectral sensitivity characteristics of the light-receiving element. (6); Receiving device for optical communication; (PD,) (PD,); Light-receiving means , (105);
Light receiving angle control means. Applicant: Minolta Camera Co., Ltd. Figure 1 Figure t[ri Figure cc Figure 3 Figure 7θ

Claims (1)

[Scope of Claims] 1. An optical communication receiving device that receives an optical signal emitted from a remote location, comprising: a light-receiving means for receiving the optical signal; and a light-receiving device that controls the light-receiving angle of the light-receiving means in accordance with manual operation. What is claimed is: 1. A receiving device for optical communication, comprising: angle control means. 2. The receiving device for optical communication according to claim 1, wherein the light receiving angle control means comprises a light flux regulating means for regulating the light flux received by the light receiving means. 3. The receiving device for optical communication according to claim 2, wherein the light flux regulating means is comprised of a light flux regulating member that can move forward and backward within the incident optical path to the light receiving means. 4. The receiving device for optical communication according to claim 3, wherein a pair of light flux regulating members are provided so as to face each other with respect to the light receiving optical axis of the light receiving means. 5. The receiving device for optical communication according to claim 4, wherein the pair of light flux regulating members can be manually operated independently of each other. 6. Each of the pair of light flux regulating members is formed into a substantially U-shape, and the center portion of each member is movable back and forth within the incident optical path to the light receiving means, and both end portions of each member are substantially orthogonal to the light receiving optical axis. 6. The optical communication receiving device according to claim 5, wherein the optical communication receiving device is supported so as to rotate around a rotation axis.