JPH07245585A - Information transmitter for vehicle - Google Patents

Abstract

PURPOSE:To make the luminous quantity of a light receiving section of a transmission destination properly setting automatically a drive current of a light emitting element of a sender depending on the configuration of a transmission line between vehicles and correcting the drive current depending on the increase/ decrease in the attenuation of the optical transmission line due to an environmental change or the like. CONSTITUTION:The attenuation in an optical transmission line 5 due to a change in the configuration of the optical transmission line 5 depending on the arrangement of vehicles is obtained by characteristic data of the optical transmission line 5 and a drive current of the light emitting element 13 is set depending on the obtained attenuation and a light receiving element 17 of the destination detects the converted current and the detected current and a preset current are compared to correct the setting value of the drive current based on the comparison value. Thus, it is not required to adjust individually constants such as resistors to set the drive current of the light emitting element 13 and even when the attenuation of the optical transmission line 5 is increased/ decreased, data are sent properly at all times and then the reliability of data transmission is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle information transmission device for transmitting information between train vehicles by optical transmission.

[0002]

2. Description of the Related Art FIG. 9 shows, for example, JP-A-60-37851.
FIG. 10 is a circuit diagram showing a configuration of a conventional information transmission device for a vehicle shown in Japanese Patent Publication, and FIG. 10 is an enlarged circuit diagram of a main part of FIG. In FIG. 9, 1 is a first vehicle and 2 is a first vehicle 1.
A plurality of second vehicles connected to each other and 3 connected to each other, 3 is a central station mounted on the first vehicle 1, and 4 is a terminal station mounted on each of the plurality of second vehicles 2. Reference numeral 5 is an optical transmission line composed of the central station 3 and the terminal stations 4, or an optical fiber connecting the terminal stations 4, and the like, 6 is a control commander for issuing a control command to the central station 3, and 7 to 9 are respectively central stations. 3 or a control device connected to the terminal station 4. Central station 3 and terminal station 4
As shown in FIG. 10, the series circuits of the opto-electric converter 10 and the electro-optical converter 11 are arranged in parallel so that the transmission directions are opposite to each other. Then, the transmission control circuit 1
2 is connected to the serial circuit in the counterclockwise transmission direction shown.

When any one of the optical transmission lines 5 is broken, the disconnection is judged by detecting that the clock signal added to the transmission data disappears. Then, the opto-electric converter 10 and the electro-optic converter connected to the illustrated right-handed transmission path 5 by using the illustrated left-handed sound transmission path 5 and the illustrated right-handed sound transmission path 5 11 is connected to the left-handed transmission path 5 shown in the figure to form a loop-shaped information transmission path.

FIG. 11 is a circuit diagram showing a concrete circuit of the opto-electric converter 10 and the electro-optical converter 11, 13 is a light emitting element for converting an electric signal into light, and 14 is a transistor for driving the light emitting element 13. , 15 is a resistor for limiting the current of the light emitting element 13 and adjusting the light output thereof, 16 is an optical connector for connecting the light emitting element 13 to the optical transmission line 5,
The electro-optical converter 11 is composed of 3 to 16. 1
Reference numeral 7 is a light receiving element that is connected to the optical transmission line 5 through the optical connector 18 and converts the output light sent through the optical transmission line 5 into a current. Reference numeral 19 amplifies the current converted by the light receiving element 17 to turn it on / off. A transistor for converting into the off signal b, 20 is a resistor for limiting the current flowing through the transistor 19, and the photoelectric conversion device 10 is constituted by the above 17 to 20.

Next, the operation will be described. In FIG. 10, when the transmission data a output from the photoelectric converter 10 of the terminal station 4-1 is transmitted to the terminal station 4-2 via the optical transmission line 5, the transmission data a is as shown in FIG. Is input to the base of the transistor 14 of the electro-optical converter 11, and the collector / emitter of the transistor 14 is turned on / off according to the input signal. When the transistor 14 is turned on, the current i ₁ flows through the path of the power source P ₁ → the light emitting element 13 → the resistor 15 → the transistor 14 → n ₁ . The light emitting element 13 is
An optical signal c having an optical output corresponding to the current i ₁ is output. The optical signal c is sent from the optical connector 16 through the optical transmission line 5 and the optical connector 18 to the light receiving element 17 of the photoelectric converter 10 in the terminal station 4-2. This optical signal c is converted into a current by the light receiving element 17, and the transistor 19
Then, the current is amplified and converted into an ON / OFF signal, which is input to the electro-optical converter 11 as transmission output data b. At this time, as shown in FIG. 9, the optical transmission line 5 is used for transmitting the light of the optical signal c depending on the number of optical connectors, the optical transmission line length, and the like depending on whether the adjacent vehicles are passed or not. Since the attenuation amount of the output is different, the light amount of the light output of the light emitting element 13 is adjusted in order to supply a sufficient light input signal to the light receiving element 17. This adjustment of the amount of light is performed by changing the resistance value of the resistor 15 and adjusting the current flowing through the light emitting element 13 of the electro-optical converter 11. In order to perform high-speed transmission, it is necessary to shorten the switching time, so the upper limit of the light amount is limited, and the range of the light amount takes into consideration the data transmission rate, environment resistance (temperature, etc.), and secular change. Desired.

[0006]

Since the conventional information transmission device for a vehicle is constructed as described above, an appropriate optical signal is received by the light receiving element of the data transmission destination according to the configuration of the optical transmission line between the vehicles. In order to give an input, the light output of the light emitting element of the electro-optical converter of the transmission source is obtained, and the resistance value must be individually adjusted to individually adjust the drive current of the light emitting element to correspond to it. The configuration of the optical converter cannot be one type, and the resistance value must be readjusted due to the change in the configuration of the optical transmission line between the vehicles due to the reorganization of the vehicles. Furthermore, when the amount of attenuation in the optical transmission system increases or decreases due to changes in the environment or changes over time, it does not have the function of correcting the light amount of the light emitting element of the transmission source, so the light amount of the light receiving element of the transmission destination becomes incorrect. There was a problem that data transmission was not performed properly.

The present invention has been made to solve the above problems, and the drive current value of the light emitting element is automatically set to an appropriate value according to the change in the configuration of the optical transmission line between the vehicles. In addition, even if the amount of attenuation of the optical transmission system increases or decreases due to changes in the environment or changes over time, the drive current value is corrected according to the increase or decrease, and the light amount of the light emitting element is corrected by this, and data transmission is properly performed. An information transmission device for a vehicle is provided.

Another object of the present invention is to provide an information transmission device for a vehicle which is informed when the attenuation amount of the optical transmission system has increased or decreased beyond a set value, and which can be dealt with before data transmission becomes impossible.

[0009]

An information transmission device for a vehicle according to the present invention obtains an attenuation amount of an optical transmission line due to a change in the configuration of the optical transmission line due to a reorganization of the vehicle from characteristic data of the optical transmission line, The drive current of the light emitting element is set according to the calculated attenuation amount, the current converted by the light receiving element is detected, the detected current value is compared with a preset current value, and the comparison value is determined according to the comparison value. The set value of the drive current is corrected by the above.

Further, the current converted by the light receiving element is detected, and an alarm signal is generated when the value of the detected current exceeds a preset current value.

[0011]

In the vehicle information transmission device according to the present invention, an appropriate driving current value of the light emitting element is set in accordance with the amount of attenuation due to the change in the configuration of the optical transmission line due to the rearrangement of the vehicle, and
The set drive current value of the light emitting element is corrected according to the comparison value of the detected current value of the light receiving element and the set current value, which changes due to an increase or decrease in the attenuation of the optical transmission system due to changes in the environment, changes over time, and the like.

When the detected current value of the light receiving element exceeds the set current value, an alarm signal is output.

[0013]

【Example】

Example 1. 1 is a circuit diagram showing a configuration of a vehicle information transmission device according to a first embodiment of the present invention and corresponds to FIG. 10 of a conventional example. In FIG. 1, reference numerals 4-1 and 4-2 denote terminal stations mounted in different vehicles, and the terminal station 4-1 includes an opto-electric converter 10a, an electro-optical converter 11a, and a transmission control circuit 12a. The terminal station 4-2 includes an opto-electric converter 10a, an electro-optical converter 11a, and a transmission control circuit 12.
and b. The electro-optical converter 11a is shown in FIG.
A light emitting element 13 for converting an electric signal into light as shown in FIG.
A transistor 14 for driving the light emitting element 13, a constant current circuit 21 for supplying a base current to the transistor 14 to limit a current flowing through the light emitting element 13, and a resistor for feeding back the current flowing through the light emitting element 13 to the constant current circuit 21. 22
It is composed of and. The constant current circuit 21 includes a D / A converter 23 that converts light emitting element drive current setting data (d) from a transmission control circuit 12a, which will be described later, into an analog voltage,
Output voltage of D / A converter 23 or photoelectric converter 10a
The diodes 24 and 25 provided for detecting the lower one of the output voltages of the light emitting element 1, the resistor 26, and the detected voltage are input, and a current proportional to the voltage is input to the light emitting element 1
3 and an operational amplifier 27 that outputs to the base of the transistor 14.

Further, in FIG. 1, the photoelectric converter 10a is provided.
Is a light-receiving element 17 for converting the output light sent from the electro-optical converter 11a through the optical transmission line 5 into a current, and a light-receiving element current converted by the light-receiving element 17 for conversion into an on / off signal b. A transistor 19 and a resistor 28 for converting the light receiving element current converted by the light receiving element 17 into a voltage.
And a current detection circuit 29 for detecting the light receiving element current.

Reference numerals 12a and 12b are transmission control circuits composed of a microcomputer or the like. 3 is a block diagram showing the function of the transmission control circuit 12a, and FIG. 4 is a flowchart showing the operation of the transmission control circuit 12a. 1 to 4, the knitting pattern of the vehicle is set by the knitting pattern setting means 121 such as a setting switch or a touch switch. Thereby, the optical transmission line recognition means 122 recognizes the configuration of the optical transmission line. Then, the drive current setting means 123
Outputs a drive current for an appropriate light receiving element current of the data transmission destination (step 100).

Light emitting element 13 driven by the obtained drive current
Current of the light receiving element 17 due to the output of
The current comparing means 125 compares and determines whether the light receiving element current is within a predetermined range (steps 101 to 101).
104). When the light receiving element current is out of the predetermined range, the drive current correction means 126 corrects the setting data of the drive current setting means 123 (step 104). Further, when the light receiving element current is out of the predetermined range, the alarm signal generating means 127 outputs an alarm signal (steps 105, 10).
6). Further, the transmission control circuit 12b has a function of creating and outputting transmission data composed of the light receiving element current data of the light receiving element current detected by the current detecting circuit 29 and other transmission transmission data.

FIG. 5 shows the light emitting element 13 of the electro-optical converter 11a.
6 is a block diagram showing the relationship between the light-emitting element drive current i ₁ flowing through the light-receiving element and the light-receiving element detection current i ₂ flowing through the light-receiving element 17 of the photoelectric converter 10a. FIG.
3 is a general characteristic curve showing the relationship between the light emitting element drive current i _{1 of 3} and the light output P _OUT, and FIG. 7 shows the light input P _IN in the light receiving element 17 of the photoelectric converter 10a and the light receiving element detection flowing in the light receiving element 17. It is a general characteristic curve showing the relationship with the current i ₂ .

Next, the operation will be described. In FIG. 1, transmission data a output from the opto-electric converter 10a-1a of the terminal station 4-1 is input to the electro-optical converter 11a-1a. The transmission data a input to the electro-optical converter 11a-1a is input to the + terminal of the operational amplifier 27 through the diode 25 as shown in FIG. 2, and its voltage is the L signal output from the opto-electric converter 10a-1a. At the time of, it becomes 0V,
When the output of the optoelectric converters 10a-1a is an H signal, the D / A converter 2 is also connected through the diode 24.
It becomes the value of the output voltage of 3. On the other hand, in the transmission control circuit 12a, the formation pattern of the vehicle is set in advance by setting means (not shown) such as a setting switch or a touch switch on the screen, and the optical transmission line 5 connects the vehicles from the set formation pattern. The configuration of the optical transmission line 5 is recognized as to whether the optical transmission line 5 has been used, or one vehicle or one or more vehicles have been passed between the vehicles.

In consideration of the environmental resistance (temperature, etc.) of the light emitting / receiving elements 13 and 17 and the optical connectors 16 and 18 and changes over time, the light emitting / receiving elements 13 shown in FIGS.
Based on the characteristic curve of 17 and the attenuation amount of the optical connectors 16 and 18, the characteristics and length of the optical fiber connecting the vehicles, and the like, an appropriate range of the photodetector detection current i ₂ to be extracted from the photodetector 17 of the data transmission destination (I ₂ The range (I ₁ −ΔI ₁ ) to (I ₁ + ΔI ₁ ) of the appropriate light emitting element drive current i ₁ of the light emitting element 13 corresponding to −ΔI ₂ ) to (I ₂ + ΔI ₂ ) is determined. Further, the light emitting element drive current setting data d of the light emitting element drive current I _{1 having} an intermediate value in the range of the light emitting element drive current i ₁ is used as a command value and D is set.
Output to the A / A converter 23 (step 100 in FIG. 4).

Here, an appropriate light emitting element drive current of the light emitting element 13 corresponding to an appropriate detection current of the light receiving element 17 is obtained by the following. First, the loss P _LOSS of the optical transmission line 5 is obtained from the attenuation amounts of the optical connectors 16 and 18 and the characteristics and length of the optical fiber connecting the vehicles. FIG. 7 shows an appropriate range of the light receiving element detection current i ₂ taken out from the light receiving element 17 in consideration of the environmental resistance (temperature etc.) of the light emitting / light receiving elements 13 and 17 and the optical connectors 16 and 18 and the secular change. Thus, if (I ₂ −ΔI ₂ ) to (I ₂ + ΔI ₂ ) are set, the required optical input P _IN becomes (P _I −ΔP _I ) to (P _I + ΔP _I ) from FIG. 6, and the appropriate optical output P _{OUT is obtained.} Range (Po-ΔPo) to (P
o + ΔPo) is obtained from P _IN / P _LOSS , and from FIG. 6, the range (Po−ΔPo) to (Po + ΔP) of the optical output P _OUT is obtained.
The range (I ₁ −ΔI ₁ ) to (I ₁ + ΔI ₁ ) of the appropriate light emitting element drive current i ₁ for driving the light emitting element 13 corresponding to o) is obtained.

The D / A converter 23 includes a transmission control circuit 12a.
Range of the light-emitting element drive current i ₁ from _{(I 1 -ΔI 1) ~ (} I 1
Since the light emitting element drive current setting data d of the light emitting element drive current I ₁ (FIG. 6) having an intermediate value of + ΔI ₁ ) is input, D / A
The value of the output voltage of the converter 23 is a value proportional to the light emitting element drive current setting data d. Since the operational amplifier 27 supplies the base current to the transistor 14 so that the input of the + terminal and the input of the − terminal match, the voltage applied to the resistor 22 becomes equal to the input voltage of the + terminal. That is, the value of the light emitting element drive current i ₁ flowing through the path of the power supply P ₁ → the light emitting element 13 → the transistor 14 → the resistor 22 is controlled to the value of the [+ terminal input voltage / resistance 22] of the operational amplifier 27. .

In other words, the optoelectric converters 10a-1a
The ON / OFF signal of the current is transmitted to the light emitting element 13 in synchronization with the output of the light emitting element 13, and the light emitting element drive current value at the time of the ON is included in the light emitting element drive current setting data d which is a command value from the transmission control circuit 12a. Since the values are proportional, the light emitting element 13
The driving current for the light emitting element is I ₁ , and the light emitting element 13 outputs the optical output Po determined by the characteristics of FIG. The optical output Po of the light emitting element 13 passes through the optical connector 16, the optical transmission line 5, and the optical connector 18, and the optical input P _IN (FIG. 7) is installed in another vehicle. The photoelectric converter of the terminal station 4-2. 10a-2a
Is input to the light receiving element 17 of.

The light receiving element 17 outputs a light receiving element detection current i ₂ which is determined from the characteristics shown in FIG. 7 by the light input P _IN . The light receiving element detection current i ₂ is converted into a voltage by the resistor 28, the voltage is detected by the current detection circuit 29 as light receiving element detection current data, and the detected light receiving element detection current data is sent to the transmission control circuit 12b. It is sent as data e. On the other hand, the light receiving element detection current i ₂ is amplified by the transistor 19 and converted into an ON / OFF signal to be the transmission output data b, which is the electro-optical converter 11a-2.
sent to a. The transmission control circuit 12b creates transmission data f including the input light receiving element detection current data e and other transmission transmission data, and outputs it to the electro-optical converters 11a-2b. The transmission data f is converted into light by the electro-optical converters 11a-2b in the same manner as described above, and passes through the optical transmission line 5 different from the above, and the opto-electric converters 10a-1b of the terminal station 4-1.
To the transmission control circuit 12a as transmission data g.
Is input (step 101 in FIG. 4).

The transmission control circuit 12a selects the light receiving element detection current data e from the input transmission data g (step 102 in FIG. 4), and the value of the light receiving element detection current data e and FIG.
Receiving element detected current values shown in (I ₂ + ΔI ₂₎ compared to the value receiving element detects the current value of the light receiving element detecting the current data e (I ₂ + ΔI ₂₎ not more than (Fig. 4, Step 10
3) Next, the value of the light receiving element detection current data e is compared with the light receiving element detection current value (I ₂ −ΔI ₂ ) shown in FIG. 7, and the value of the light receiving element detection current data e is I ₂
If it is + ΔI ₂ ) or more, it is determined that the light emitting element drive current setting data d is a proper value, and the data transmission is continued as it is (FIG. 4, step 104).

Next, in the optical transmission system, the case where the attenuation amount of the optical transmission line 5 increases or decreases and the light amount of the transmission destination deviates from the above range will be described. First, the case where the attenuation amount of the optical transmission line 5 is decreased and the optical input P _IN to the light receiving element 17 is increased will be described. As the light input P _IN to the light receiving element 17 increases, the light receiving element detection current i ₂ of the light receiving element 17 increases. The light-receiving element detection current data e of the increased light-receiving element detection current i ₂ is transmitted together with other transmission transmission data in the same manner as described above in the transmission control circuit 1.
2b, the electro-optical converters 11a-2b, the optical transmission line 5, and the opto-electric converters 10a-1b are transmitted to the transmission control circuit 12.
Input to a.

The transmission control circuit 12a selects the light receiving element detection current data e from the input light receiving element detection current data e and the transmission data g consisting of other transmission transmission data (step 102 in FIG. 4), and detects the light receiving element detection current. shown in value and 7 of the data e compared with the values of the light receiving element detecting a current (I ₂ + ΔI _2), there the value of the light receiving element detecting a current data e is a value of the light receiving element detecting a current (I ₂ + ΔI ₂₎ or Ba (Figure 4, Step 1
03), the light emitting element drive current setting data d is (d-Δd)
The light emitting element drive current setting data (d-
In order to output Δd) to the constant current circuit 21 and to notify the crew member of the vehicle of the excessive light amount, the excessive light amount alarm signal h is output to the alarm device (not shown) of the central office via the electro-optical converters 11a-1b (not shown). Step 105 in FIG. 4).

Corrected light emitting element drive current setting data (d
Due to −Δd), the current for driving the light emitting element 13 through the constant current circuit 21 decreases, and the optical output Po decreases. The optical transmission data whose optical output Po has been reduced is sent to the photoelectric converters 10a-2a of the terminal station 4-2 via the optical transmission line 5, and the reduced optical input P _IN is input to the light receiving element 17. Therefore, the light receiving element detection current i ₂ decreases. This correction is performed until the light receiving element detection current i ₂ falls within the range of (I ₂ −ΔI ₂ ) to (I ₂ + ΔI ₂ ). That is, the decrease amount of the attenuation amount of the optical transmission line 5 is corrected by the decrease of the light emitting element drive current.

Next, the case where the amount of attenuation in the optical transmission line increases and the amount of light at the transmission destination decreases will be described. At this time, the operation reverse to the above is performed, and the transmission control circuit 12a causes the value of the light receiving element detection current data e of the light receiving element detection current i ₂ selected from the transmission data g and the value of the light receiving element detection current shown in FIG. (I
₂ + ΔI ₂ ) and the value of the light receiving element detection current data e is less than or equal to the value of the light receiving element detection current (I ₂ + ΔI ₂ ) (FIG. 4, step 103), then the light receiving element detection current data e
Value and the value of the light receiving element detection current shown in FIG. 7 (I ₂ −Δ
I ₂ ), if the value of the light receiving element detection current data e is less than or equal to the light receiving element detection current value (I ₂ −ΔI ₂ ), the light emitting element drive current setting data d is corrected to (d + Δd) and corrected. In order to output the light emitting element drive current setting data (d + Δd) to the constant current circuit 21 and notify the crew member of the vehicle of the insufficient light amount, the light amount insufficient warning signal i is sent to the electro-optical converter 11a.
It outputs to the alarm device (not shown) of the central office via -1b (step 106 in FIG. 4).

Corrected light emitting element drive current setting data (d
By + Δd), the current for driving the light emitting element 13 through the constant current circuit 21 increases, and the optical output Po increases. The optical transmission data having the increased optical output is sent to the photoelectric converters 10a-2a of the terminal station 4-2 via the optical transmission line 5, and the increased optical input P _IN is input to the light receiving element 17. , The light receiving element detection current i ₂ increases. This correction is performed until the light receiving element detection current i ₂ falls within the range of (I ₂ −ΔI ₂ ) to (I ₂ + ΔI ₂ ). That is, the increase in the attenuation of the optical transmission line 5 is corrected by the increase in the light emitting element drive current.

As described above, according to the first embodiment of the present invention, even if the composition of the optical transmission line between the vehicles is changed due to the reorganization of the vehicle or the like and the attenuation amount of the optical transmission line is changed, the light emitting element is automatically changed. Appropriate drive current is set, proper data transmission can be performed without individually adjusting constants such as resistance in the electro-optical converter as in the conventional case, and the electro-optical converter has one type of configuration. Even if the amount of attenuation of the optical transmission line changes due to the environment, aging, etc., the drive current is corrected according to the change, and the reliability of data transmission is improved. In addition, the attenuation of the optical transmission line changes due to the environment and changes over time,
When the value of the light receiving element detection current of the destination light receiving element exceeds the predetermined range, the alarm signal that is output can take action before the data transmission becomes impossible and the data transmission becomes impossible. Is prevented.

Example 2. In the first embodiment, when the attenuation amount of the optical transmission line 5 changes due to the environment, aging, etc., the increase / decrease in the received light amount is obtained from the light receiving element detection current of the light receiving element 17, so that the resistor 28 inserted in series is used. Although the voltage is converted and detected, a current detection sensor using a Hall element or a current transformer may be used as the current detection sensor.

Example 3. Further, in the first embodiment, the light receiving element detection current data e of the light receiving element 17 of the data transmission destination
Is fed back to the transmission control circuit 12a of the data transmission source via the transmission control circuit 12b, the electro-optical converters 11a-2b, the optical transmission line 5, and the opto-electric converters 10a-1b, and the light receiving element detection is performed in the transmission control circuit 12a. Although it is shown that the value of the current data e is determined to be within a predetermined range and the value of the light emitting element drive current data d is corrected,
As shown in FIG. 8, a data transmission destination transmission control circuit 1
In 2b, it is determined whether or not the value of the light receiving element detection current data e is within a predetermined range, and the transmission control circuit 12 of the data transmission source is determined.
a current increase command j or current decrease command k to the electric wires 30, 31
And the transmission control circuit 12a may correct the light emitting element drive current data d based on the received current increase command j or current decrease command k, and the same effect as the first embodiment is obtained.

Example 4. Further, in the first embodiment, the constant current circuit 21 for controlling the light emitting element drive current is shown in which the D / A converter 23 is used so that the light emitting element drive current can be set in a wide range. It is also possible to provide a required number of analog values, switch the analog values by the transmission control circuit 12a, and input the analog values to the cathode side of the diode 24 of the D / A converter 23, and the same effect as in the first embodiment is obtained. .

[0034]

As described above, according to the present invention, even if the configuration of the optical transmission line between the vehicles is changed due to the reorganization of the vehicle or the like, and the attenuation amount of the optical transmission line is changed, the light emitting element can be properly adjusted. Even if the drive current is set and the attenuation of the optical transmission line changes due to changes in the environment or aging, the drive current is corrected in accordance with the change. It is not necessary to individually adjust constants such as resistance in the converter, the device configuration is unified, and the device is easy to handle.

Further, an alarm signal is output when the attenuation amount of the optical transmission line changes due to the environment, aging, etc., and the value of the light receiving element detection current of the light receiving element at the transmission destination exceeds a predetermined range. As a result, it is possible to deal with the problem before the data transmission becomes impossible and prevent the situation where the data transmission becomes impossible.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of a vehicle information transmission device according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing details of the electro-optical converter shown in FIG.

FIG. 3 is a block diagram showing functions of a transmission control circuit 12a shown in FIG.

4 is a flowchart showing an operation of the transmission control circuit 12a shown in FIG.

FIG. 5 is a block diagram showing a relationship between a current i ₁ flowing through a light emitting element of the electro-optical converter and a current i ₂ flowing through a light receiving element of the photoelectric converter.

FIG. 6 is a current i ₁ flowing through a light emitting element in the electro-optical converter.
2 is a general characteristic curve showing the relationship between the light output P _OUT and the light output P _OUT .

FIG. 7 is a general characteristic curve showing a relationship between an optical input P _IN input to a light receiving element in a photoelectric converter and a light emitting element detection current i ₂ flowing in the light receiving element.

FIG. 8 is a circuit diagram showing a configuration of a vehicle information transmission device according to another embodiment of the present invention.

FIG. 9 is a circuit diagram showing a configuration of a conventional vehicle information transmission device.

10 is an enlarged circuit diagram of a main part of FIG.

11 is a circuit diagram showing details of a main part of FIG.

[Explanation of symbols]

 5 optical transmission path 13 light emitting element 17 light receiving element 123 drive current setting means 126 drive current correcting means 127 alarm signal generating means

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H04B 10/04 H04Q 9/00 301 B

Claims (2)

[Claims] 1. Information transmission of a vehicle for performing vehicle-to-vehicle data transmission by connecting a light emitting element for converting an electric signal into an optical signal and a light receiving element for converting the optical signal into an electric current, which are respectively mounted on the vehicle, through an optical transmission path. In the device, the amount of attenuation of the optical transmission line due to a change in the configuration of the optical transmission line based on the formation of the vehicle is obtained from the characteristic data of the optical transmission line, and the drive current of the light emitting element is determined according to the obtained amount of attenuation. A drive current setting means for setting and detecting the current converted by the light receiving element,
Compare the detected current value with the preset current value,
An information transmission device for a vehicle, comprising: a drive current correction means for correcting the set value of the drive current according to the comparison value. 2. Information transmission of a vehicle for transmitting data between vehicles by connecting a light emitting element for converting an electric signal into an optical signal and a light receiving element for converting the optical signal into a current, which are respectively mounted on the vehicle, through an optical transmission path. In the device, the amount of attenuation of the optical transmission line due to a change in the configuration of the optical transmission line based on the formation of the vehicle is obtained from the characteristic data of the optical transmission line, and the drive current of the light emitting element is determined according to the obtained amount of attenuation. A drive current setting means for setting and detecting the current converted by the light receiving element,
Compare the detected current value with the preset current value,
Alarm signal generating means for correcting the set value of the drive current according to the comparison value and for generating an alarm signal when the value of the detected current exceeds the set current value. Vehicle information transmission device.