JPH07254743A - Semiconductor laser equipment with protective circuit - Google Patents

Abstract

PURPOSE:To provide a semiconductor laser equipment with a protective circuit wherein breakdown of a semiconductor laser diode can be avoided for a DC overcurrent, a high power supply voltage is unnecessary, and the adjustment of setting current value of the semiconductor laser diode is easily enabled. CONSTITUTION:A resistor 3 which is connected in series with a semiconductor laser diode 2 and leads out a voltage from the current flowing in the semiconductor laser diode 2, and a transistor 5 which is arranged in a bypass path 4 divided from a current supplying path 1 which supplies a current to the semiconductor laser diode 2 and controls a current flowing in the semiconductor laser diode 2 by making a current flow from the current supplying path 1 to the bypass path 4, on the basis of the voltage between both of the ends of the resistor 3 are installed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser device with a protection circuit having a built-in protection circuit.

[0002]

2. Description of the Related Art In a semiconductor laser device provided in an optical disk device, a laser printer or the like, a device in which an optical output is automatically adjusted by a front light monitor,
When dew condensation occurs on the light receiving surface of the monitor, it is determined that the light output is small and the operating current of the semiconductor laser diode is increased more than necessary.

Semiconductor laser diodes are suddenly destroyed when the operating current increases. This is due to COD (instantaneous optical damage) in which the laser end face is destroyed by the increased own optical output. Further, even in a model in which the light output is automatically adjusted by a rear light monitor provided in the semiconductor laser diode, an overcurrent is erroneously caused to flow during the adjustment to cause COD breakdown.

A conventional semiconductor laser device with a protection circuit is
In order to prevent the above COD, a capacitor 51 is connected in parallel with the semiconductor laser diode 50 as shown in FIG. It is also possible to connect a CRD (constant current element) 52 in series with the semiconductor laser diode 50 as shown in FIG.

[0005]

However, in the structure in which the capacitor 51 is connected in parallel with the semiconductor laser diode 50, it is only possible to absorb a very short overcurrent such as noise at power-on, and the The destruction of the semiconductor laser diode 50 cannot be prevented against overcurrent. In addition, the semiconductor laser diode 50
If a CRD 52 is connected in series with the CRD52, a high power supply voltage is required. For example, when connected to a device driven by 2.5V, the semiconductor laser diode has 2V and the constant current element has 2V.
If a voltage of V is required, it becomes 6.5 V in total, and it becomes impossible to drive the device with four 1.5 V dry batteries. Moreover, since the set current of the semiconductor laser diode is determined by the CRD 52, it is difficult to finely adjust the set current.

In view of the above circumstances, the present invention can avoid the destruction of the semiconductor laser diode even with respect to an overcurrent of DC, does not require a high power supply voltage, and can set a fine setting current of the semiconductor laser diode. The semiconductor laser diode can be adjusted, and the semiconductor laser diode can be prevented from being damaged by an overcurrent due to a change in environmental temperature, and the terminal compatibility with a conventional semiconductor laser device having a three-terminal configuration can be ensured. An object of the present invention is to provide a semiconductor laser device with a protection circuit capable of performing the protection.

[0007]

The first structure of the present invention is as follows.
A resistor connected in series with the semiconductor laser diode to extract a voltage from the current flowing through the semiconductor laser diode and a bypass path branched from the current supply path for supplying the current to the semiconductor laser diode, and the voltage across the resistor. And a control element for controlling a current flowing through the semiconductor laser diode by causing a current from the current supply path to flow in the bypass path based on the value.

In the second configuration, in the first configuration, the resistor may include a thermistor.

According to a third structure, in the first or second structure, the control element comprises a transistor, a voltage across the resistor is applied between a base and an emitter of the transistor, and a collector of the transistor. The bypass path may be formed between the emitter and the emitter.

According to a fourth structure, in the first or second structure, the control element comprises a thyristor, a voltage across the resistor is applied between a gate and a cathode of the thyristor, and an anode of the thyristor. The bypass passage may be formed between the cathode and the cathode.

A fifth configuration is the same as the third or fourth configuration, but is connected to a connection point between the base or gate of the control element, the resistor and the semiconductor laser diode to monitor the current flowing through the semiconductor laser diode. A current monitor line may be provided.

According to a sixth structure, in the fifth structure, the semiconductor laser diode and the control element are arranged on a common electrode provided in the case, and three terminals are projected from the case, and the first terminal is provided. Is connected to a common electrode, a wire bonding serving as a current monitor line is connected to a portion of the second terminal arranged in the case, and a portion of the third terminal arranged in the case is connected to a collector or an anode of the control element by wire bonding. At the same time, the portions inside the case of the second terminal and the third terminal may be connected by the resistance.

According to a seventh structure, in the third or fourth structure, a photodiode for detecting the light amount of the semiconductor laser diode by making the backward emission light of the semiconductor laser diode incident is provided with the current supply path at one end side thereof. May be connected to and provided.

An eighth structure is the same as the seventh structure except that a semiconductor laser diode, a photodiode and a control element are arranged on a common electrode provided in the case, and three terminals are projected from the case. The first terminal is connected to the common electrode, the portion of the second terminal arranged in the case is connected to the photodiode by wire bonding, and the portion of the third terminal arranged in the case is wire bonded to the collector or anode of the control element. And a resistor is disposed on the resin region formed between the in-case arrangement portions of the second terminal and the third terminal, and one end of this resistor is the case of the third terminal. Even if the other end of the resistor is connected to the semiconductor laser diode and the base or gate of the control element by wire bonding, It is the casting.

[0015]

According to the first structure, when the current flowing through the semiconductor laser diode increases, the voltage value taken out by the resistor also increases accordingly. The larger the voltage value of this resistor, the larger the current that flows in the bypass under the control of the control element. As a result, even if a DC overcurrent is supplied to the device, the semiconductor laser diode has a certain current or more. Will not flow. Alternatively, when the voltage value across the resistor becomes a certain value or more, all the current from the current supply path flows into the bypass path, and no current is supplied to the semiconductor laser diode. As a result, COD of the semiconductor laser diode is prevented.

The set current value of the semiconductor laser diode can be easily adjusted by the resistance value of the resistor. Furthermore, it can be said that the voltage required for driving the control element only increases as the drive voltage, and the drive power supply of the device hardly increases.

According to the second structure, the following effects occur. That is, in the semiconductor laser diode, when the operating temperature range is T1 to T2 (T1 <T2), the temperature T2
There is a possibility that the limiting current set in step 2 will exceed the COD level at the temperature T1. In this configuration, since the resistance includes the thermistor, even if the temperature decreases from T2 to T1, the resistance value of the resistance at T1 becomes higher than the resistance value at T2. The voltage value at both ends of is also that much higher. This makes it possible to avoid COD breakdown of the semiconductor laser diode even when the operating temperature drops to T1.

According to the third configuration, the semiconductor laser device with the protection circuit can be constructed by using the transistor as the control element.

According to the fourth configuration, the semiconductor laser device with the protection circuit can be constructed by using the thyristor as the control element.

According to the fifth structure, the current flowing through the semiconductor laser diode can be monitored by the current monitor line.

According to the sixth structure, the semiconductor laser device with the protection circuit capable of monitoring the current flowing through the semiconductor laser diode can be composed of three terminals, and the terminal compatibility with the existing semiconductor laser device can be secured. Further, a semiconductor laser diode and a control element (transistor or thyristor) are installed on the common electrode, and a semiconductor assembling process is used for this installation to facilitate manufacturing. Furthermore, since each element is installed in a plane, wiring can be facilitated by bonding.

According to the seventh structure, a photodiode for detecting the light quantity of the semiconductor laser diode by making the backward emission light of the semiconductor laser diode incident is provided with one end side thereof being connected to the current supply path. Therefore, the light output of the semiconductor laser diode can be monitored by using the photodiode.

According to the eighth structure, the semiconductor laser device with the protection circuit for monitoring the optical output of the semiconductor laser diode by the photodiode can be composed of three terminals, and the terminal compatibility with the existing semiconductor laser device is provided. Can be secured. Further, a semiconductor laser diode and a control element (transistor or thyristor) are installed on the common electrode, and a semiconductor assembling process is used for this installation to facilitate manufacturing. Furthermore, since each element is installed in a plane, wiring can be facilitated by bonding.

[0024]

【Example】

(Embodiment 1) The present invention will be described below with reference to the drawings showing the embodiment.

FIG. 1 is a circuit diagram of a semiconductor laser device with a protection circuit. The anode side of the semiconductor laser diode 2 is connected to the current supply path 1, and the resistor 3 is connected to the cathode side of the semiconductor laser diode 2. That is,
A semiconductor laser diode 2 and a resistor 3 are connected in series to the current supply path 1.

Further, in the bypass path 4 branched from the current supply path 1 on the anode side of the semiconductor laser diode 2,
The collector of the transistor 5 is connected. Also,
The base of the transistor 5 is the semiconductor laser diode 2
Is connected to the connection point of the resistor 3 and the emitter of the transistor 5 is connected to the other end of the resistor 3.

Base of Transistor 5
The voltage between the emitters is set to ~ 0.6V. Therefore, when the current value I flowing through the semiconductor laser diode 2 (that is, the current value flowing through the resistor 3) is I <0.6 / R (R is the resistance value of the resistor 3), the transistor 5 is in the OFF state. Yes, all the current flows through the semiconductor laser diode 2. On the other hand, when the current increases and becomes I> 0.6 / R, a current flows between the base and the emitter of the transistor 5 and the collector and the emitter become conductive. As a result, the increased current flows through the bypass path 4, and the increase in the current flowing through the semiconductor laser diode 2 can be suppressed, and COD of the semiconductor laser diode 2 can be avoided.

The set current value of the semiconductor laser diode 2 can be easily adjusted by the resistance value R of the resistor 3. Furthermore, the voltage (0.
6V) only increases as the drive voltage. Therefore,
A semiconductor laser device with such a protection circuit is provided, for example, in 2.
Even when connected to a device driven by 5V, the semiconductor laser diode has a total of 2V and the resistor 3 has a total of 0.6V, which is 5.1V.
The device can be driven by four 1.5 V dry batteries.

FIG. 2 is a current measurement circuit diagram for verifying the above-mentioned operation characteristics in the semiconductor laser device with the protection circuit.

Reference numeral 6 in FIG. 2 is a transistor for adjusting the current flowing through the semiconductor laser device with the protection circuit. The transistor 6 can adjust the current flowing between its collector and emitter (ground) by adjusting the current flowing through its base.

Reference numeral 7 in the figure denotes an ammeter for measuring the current flowing through the semiconductor laser diode 2 (hereinafter referred to as the first ammeter). The first ammeter 7 is provided in the current supply path 1
Above, ie, power supply (+ 5V) and semiconductor laser diode 2
Connected to the anode side of. Reference numeral 8 in the figure denotes an ammeter for measuring the current flowing through the entire semiconductor laser device with a protection circuit (hereinafter referred to as a second ammeter). The second ammeter 8 is the same as the transistor 6 described above.
Is connected between the collector and the resistor 3. Further, 9 in the figure is an ammeter for detecting the base current of the transistor 6 (hereinafter referred to as a third ammeter).

FIG. 3 is a graph showing the operating characteristics of the semiconductor laser device with the protection circuit, which is examined by the current measuring circuit of FIG. The horizontal axis is the base current flowing in the transistor 6 detected by the third ammeter 9, and the vertical axis is the operating current. Graph 1 shows the entire operating current of the semiconductor laser device with the protection circuit, which is detected by the second ammeter 8.
Graph 2 shows the operating current of the semiconductor laser diode 2 detected by the first ammeter 7.

As is apparent from this figure, if the base current of the transistor 6 increases, the operating current increases in both graphs 1 and 2 in proportion to the base current up to about 0.3 mA.
However, when it exceeds approximately 0.3 mA, the graph 1 increases as it is in proportion to the base current, but the graph 2 becomes constant at a position of approximately 50 mA, and the COD of the semiconductor laser diode 2 is avoided.

FIG. 4 shows the entire operating current of the semiconductor laser device with a protection circuit (measured by the second ammeter 8) detected by the second ammeter 8 and the optical output of the semiconductor laser diode 2 (semiconductor laser). 3 is a graph showing a relationship with (measured by disposing an optical output measuring device in front of the diode 2). As is clear from this graph, the optical output of the semiconductor laser diode 2 is maintained substantially constant even when the current flowing through the entire semiconductor laser device with the protection circuit exceeds approximately 50 mA.

As shown in FIG. 5, a semiconductor laser device with a protection circuit having a reverse polarity to the structure of FIG. 1 may be constructed.

FIG. 6 shows a monitor line 20 for monitoring the current flowing through the semiconductor laser diode 2 in the circuit configuration of FIG. Monitor line 20
Is connected to the cathode side of the semiconductor laser diode 2.

FIG. 7 is a plan view of a semiconductor laser device with a protection circuit showing an arrangement formation example of each element in the package in the circuit configuration of FIG.

The case 12 has a laser beam emitting window 12a.
And the common electrode 13 provided in the case 12
The semiconductor laser diode 2 is arranged close to the upper emission window 12a so that the front light emission position formed on the end face of the semiconductor laser diode 2 faces the emission window 12a. A transistor 5 is arranged and formed on the common electrode 13 on the rear side of the semiconductor laser diode 2.

From the case 12, three terminals 15 and 2 are provided.
0 and 17 are projected. The first terminal 15 is connected to the common electrode 13. The in-case portion 20a of the second terminal 20 is connected to the cathode side of the semiconductor laser diode 2 and the base side of the transistor 5 by wire bonding, and a current monitor line is formed by the above wire bonding. The in-case arrangement portion 17a of the third terminal 17 is connected to the collector of the transistor 5 by wire bonding. Further, the in-case arrangement portion 20 of each of the second terminal 20 and the third terminal 17 is provided.
A resistor 3 is arranged and connected between a and 17a.

With the structure arranged as described above, the semiconductor laser device with the protection circuit for monitoring the current flowing through the semiconductor laser diode 2 can be constructed with three terminals, and the terminal compatibility with the existing semiconductor laser device can be achieved. Can be secured. Further, although the semiconductor laser diode 2 and the transistor 5 are arranged and formed on the common electrode 13, a semiconductor assembling process can be used for this arrangement and formation, which facilitates manufacturing. Furthermore, since each element is installed in a plane, wiring can be facilitated by bonding. This is the conventional C
The drawback of the AN type semiconductor laser diode is that the lead terminal and the electrode surface of the semiconductor laser diode are orthogonal to each other, it is difficult to wire bond when the elements are combined, and the material itself is conductive. This eliminates the disadvantage that the parts cannot be insulated and arranged.

(Embodiment 2) Another embodiment of the present invention will be described below with reference to FIGS.

The semiconductor laser device with a protection circuit of this embodiment has a structure in which a photodiode 11 for detecting the optical output of the semiconductor laser diode 2 is provided in addition to the structure of FIG. 1 of the first embodiment. The cathode side of 11 is connected to the anode side of the semiconductor laser diode 2. With this configuration, the backward emission light of the semiconductor laser diode 2 is received by the photodiode 11, and at this time, a reverse current flows through the photodiode 11, and the current can be monitored at the terminal C.

FIG. 9 is a plan view of a semiconductor laser device with a protection circuit showing an example of arrangement and formation of a package of each element in the circuit configuration of FIG.

The case 12 has a laser beam emitting window 12a.
And the common electrode 13 provided in the case 12
The semiconductor laser diode 2 is arranged close to the upper emission window 12a so that the front light emission surface formed on the end face of the semiconductor laser diode 2 faces the emission window 12a. Further, the photodiode 11 is arranged and formed on the common electrode 13 so as to receive the backward emission light of the semiconductor laser diode 2.
Further, a transistor 5 is arranged and formed on the rear side of the photodiode 11.

From the case 12, the three terminals 15, 1
6 and 17 are projected. The first terminal 15 is connected to the common electrode 13, and the second terminal 16 is disposed inside the case 1
6a is connected to the photodiode 11 by wire bonding, the in-case arrangement portion 17a of the third terminal 17 is connected to the collector of the transistor 5 by wire bonding, and the second terminal 16 and the third terminal 17 are connected.
The resistor 3 is arranged on the resin region formed between the respective in-case arrangement portions 16a and 17a in and. One end of the resistor 3 is connected to the in-case arrangement portion 17a of the third terminal 17, and the other end of the resistor 3 is connected to the semiconductor laser diode 2 and the base of the transistor 5 by wire bonding.

With the structure arranged as described above, a semiconductor laser device with a protection circuit for monitoring the optical output of the semiconductor laser diode 2 by the photodiode 11 is provided.
It can consist of terminals. Further, although the semiconductor laser diode 2 and the transistor 5 are arranged and formed on the common electrode 13, a semiconductor assembling process can be used for this arrangement and formation, which facilitates manufacturing. Furthermore, because it is installed in a plane like this,
Wiring by bonding becomes easy.

FIG. 10 is a cross-sectional plan view of a semiconductor laser device with a protection circuit showing another example of arrangement and formation in the circuit configuration of FIG. In this arrangement formation example, the semiconductor laser diode 2 is formed on the substrate of the photodiode 11. This can simplify the semiconductor assembling process of the semiconductor laser device with the protection circuit.

(Embodiment 3) Another embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 11, the semiconductor laser device with a protection circuit of this embodiment has a structure in which a resistor 3 and a thermistor 3'are connected in parallel. As an arrangement forming example in this circuit configuration, FIG. 7 of the first embodiment and FIG. 9 and FIG.
0 has the same configuration as that of the resistor 0 in the arrangement formation example.
On the other hand, the thermistor 3'may be formed three-dimensionally in parallel or in parallel with the resistor 3 in a plane.

With the above arrangement, COD of the semiconductor laser diode can be prevented even when the temperature of the environment changes. This will be described below.

In the semiconductor laser diode for CD, as shown in FIG. 12, in order to generate an optical output of 4 mW, its operating current is 46 mA at 0 ° C. (T1) and 25 ° C.
It becomes 55 mA at (T2) and 64 mA at 50 ° C. Then, when the limiting current is set to 64 mA so that an optical output of 4 mW can be obtained even at 50 ° C., as shown in FIG.
The maximum light output at 2 is about 8 mW, and the maximum light output at the temperature T1 is 12 mW in calculation.

When the COD destruction level of the semiconductor laser diode is 12 mW or less, the semiconductor laser diode is destroyed by an overcurrent at the temperature T1 in the above setting of the limiting current of 64 mA.

Here, in order to always obtain an optical output of 4 mW against temperature fluctuation, the limiting current is 4 at the temperature T1.
It may be 6 mA, 55 mA at temperature T2, and 64 mA at temperature T3.

In order to cause such fluctuation of the limiting current, when the base-emitter voltage of the transistor 5 is set to 0.6 V, the combined resistance of the resistor 3 and the thermistor 3'is 13.0 Ω at the temperature T1. The temperature T2 may be changed to 10.9Ω and the temperature T3 may be changed to 9.4Ω.

Table 1 below shows the characteristics when a commercially available thermistor having the temperature characteristics shown in FIG. 13 and a resistor 3 having a resistance of 12.6Ω are connected in parallel.

[0056]

[Table 1]

FIG. 14 is a graph showing the fluctuation of the maximum light output in Table 1 above, that is, the operating region by temperature compensation. As can be seen from this graph, by using the thermistor 3'having the characteristics shown in Fig. 13, the light output is limited to 6.0 mW or less in the temperature range of 0 to 50 ° C.

(Embodiment 4) Another embodiment of the present invention will be described below with reference to FIGS.

In the semiconductor laser device with the protection circuit of this embodiment, instead of the transistor 5 as the control element shown in the above embodiments, as shown in FIG.
It is a configuration using. That is, the voltage of the resistance value of the resistor 3 (or the combined resistance value of the resistor 3 and the thermistor 3 ′ connected in parallel) is applied between the gate and the cathode of the thyristor 10, and the thyristor 10 is connected. A bypass passage 4 is formed between the anode and the cathode.

According to this structure, when a current flows through the resistor 3 (or a combined resistor formed by parallel connection of the resistor 3 and the thermistor 3 '), a voltage is generated between the gate and the cathode of the thyristor 10, and this voltage value becomes When it reaches a predetermined value (corresponding to a value for preventing the semiconductor laser diode 2 from causing COD breakdown), the thyristor 10 is turned on, and almost all of the supplied current passes through the bypass path 4, and the semiconductor laser diode 2 is supplied with current. CO of semiconductor laser diode 2
D is avoided.

FIG. 16 is a graph obtained by investigating the operating characteristics of the semiconductor laser device with the protection circuit of the present embodiment by the current measuring circuit of FIG. 2 shown in the first embodiment. The horizontal axis is the base current flowing in the transistor 6 detected by the third ammeter 9, and the vertical axis is the operating current. Graph 1
Shows the total operating current of the semiconductor laser device with the protection circuit detected by the second ammeter 8, and graph 2 shows the first operating current.
The operating current of the semiconductor laser diode 2 detected by the ammeter 7 of FIG.

As is clear from this figure, as the base current increases, the operating current increases in graphs 1 and 2 in proportion to the base current up to about 0.3 mA. However, about 0.3m
When it exceeds A, the graph 1 increases as it is in proportion to the base current, but the graph 2 increases about 50.
The current flowing through the semiconductor laser diode 2 at a position exceeding mA is about 0 mA, and the C of the semiconductor laser diode 2 is C.
OD will be avoided.

Even in the structure having the thyristor 10 in place of the transistor as described above, as shown in FIG. 17, compatibility with the existing semiconductor laser device with the protection circuit can be ensured by the three-terminal structure.

[0064]

As described above, according to the present invention, COD breakdown of the semiconductor laser diode due to overcurrent is avoided, a high driving power supply voltage is not required, and the set current value of the semiconductor laser diode is reduced. Easy to adjust. When the resistor includes the thermistor, it is possible to avoid the COD breakdown of the semiconductor laser diode, which tends to occur when the temperature of the use environment falls below the set temperature. A semiconductor laser device with a protection circuit equipped with a monitor function is configured with three terminals to ensure terminal compatibility with existing devices and to facilitate manufacturing and bonding wiring using the semiconductor device assembly process. Produce an effect.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a semiconductor laser device with a protection circuit of the present invention.

FIG. 2 is a circuit diagram of a current measuring circuit for measuring a current of the semiconductor laser device with a protection circuit of FIG.

3 is a graph showing the relationship between the operating current of the entire circuit and the operating current of the semiconductor laser diode with respect to the base current in the current measuring circuit of the semiconductor laser device with the protection circuit of FIG.

4 is a graph showing the relationship between the operating current of the entire circuit in the semiconductor laser device with a protection circuit of FIG. 1 and the optical output of the semiconductor laser diode.

FIG. 5 is a circuit diagram of a semiconductor laser device with a protection circuit, which has a polarity opposite to that of FIG.

6 is a circuit of a semiconductor laser device with a protection circuit having a line for monitoring the current of the semiconductor laser diode in the configuration of FIG.

7 is a plan view of a semiconductor laser device with a protection circuit, showing an example of arrangement and formation of respective elements in a package in the circuit configuration of FIG.

FIG. 8 is a circuit diagram of a semiconductor laser device with a protection circuit, which has a photodiode for monitoring the optical output of the semiconductor laser diode in the configuration of FIG.

9 is a plan view of a semiconductor laser device with a protection circuit, showing an example of arrangement and formation of each element in a package in the circuit configuration of FIG.

10 is a plan view of a semiconductor laser device with a protection circuit showing another example of arrangement and formation of each element in a package in the circuit configuration of FIG.

FIG. 11 is a circuit diagram showing a semiconductor laser device with a protection circuit in which a thermistor is connected in parallel to a resistor.

FIG. 12 is a graph showing temperature characteristics of a semiconductor laser device with a protection circuit.

FIG. 13 is a graph showing temperature characteristics of the thermistor.

FIG. 14 is a graph showing an operating region of a semiconductor laser device with a protection circuit, which is temperature-compensated.

FIG. 15 is a circuit diagram of a semiconductor laser device with a protection circuit having a thyristor as a control element.

16 is a graph showing the relationship between the operating current of the entire circuit and the operating current of the semiconductor laser diode with respect to the base current in the current measuring circuit of the semiconductor laser device with the protection circuit of FIG.

17 is a cross-sectional plan view showing an arrangement formation example of each element in the package in the circuit configuration of FIG.

FIG. 18 is a circuit diagram of a conventional semiconductor laser device with a protection circuit.

FIG. 19 is a circuit diagram of a conventional semiconductor laser device with a protection circuit.

[Explanation of symbols]

 1 Current Supply Path 2 Semiconductor Laser Diode 3 Resistance 3'Thermistor 4 Bypass Path 5 Transistor (Control Element) 10 Thyristor (Control Element) 11 Photodiode 12 Case 13 Common Electrode 15 First Terminal 16 Second Terminal 16a Arrangement in Case Part 17 Third terminal 17b Placed part in case 20 Second terminal

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[Procedure amendment]

[Submission date] September 16, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 6

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 8

[Correction method] Change

[Correction content]

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

According to a sixth structure, in the fifth structure, the semiconductor laser diode and the control element are arranged on a common electrode provided in the case, and three terminals are projected from the case, and the first terminal is provided. Is connected to the common electrode, wire bonding serving as a current monitor line is connected to the portion of the second terminal arranged in the case, and the portion of the third terminal arranged in the case is connected to the emitter or cathode of the control element by wire bonding. At the same time, the portions inside the case of the second terminal and the third terminal may be connected by the resistance.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

An eighth structure is the same as the seventh structure except that a semiconductor laser diode, a photodiode and a control element are arranged on a common electrode provided in the case, and three terminals are projected from the case. The first terminal is connected to the common electrode, the portion of the second terminal located in the case is connected to the photodiode by wire bonding, and the portion of the third terminal located in the case is wire bonded to the emitter or cathode of the control element. And a resistor is disposed on the resin region formed between the in-case arrangement portions of the second terminal and the third terminal, and one end of this resistor is the case of the third terminal. Even if the other end of the resistor is connected to the semiconductor laser diode and the base or gate of the control element by wire bonding, It is the casting.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] 0023

[Correction method] Change

[Correction content]

According to the eighth structure, the semiconductor laser device with the protection circuit for monitoring the optical output of the semiconductor laser diode by the photodiode can be composed of three terminals, and the terminal compatibility with the existing semiconductor laser device can be achieved. Can be secured. Further, a semiconductor laser diode and a control element (transistor or thyristor) are installed on the common electrode, and a semiconductor assembling process is used for this installation to facilitate manufacturing. Furthermore, since each element is installed in a plane, wiring can be facilitated by bonding.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0039

[Correction method] Change

[Correction content]

From the case 12, three terminals 15 and 2 are provided.
0 and 17 are projected. The first terminal 15 is connected to the common electrode 13. The in-case portion 20a of the second terminal 20 is connected to the cathode side of the semiconductor laser diode 2 and the base side of the transistor 5 by wire bonding, and a current monitor line is formed by the above wire bonding. The in-case arrangement portion 17a of the third terminal 17 is connected to the emitter of the transistor 5 by wire bonding. Further, the in-case arrangement portion 20 of each of the second terminal 20 and the third terminal 17 is provided.
A resistor 3 is arranged and connected between a and 17a.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0040

[Correction method] Change

[Correction content]

With the structure arranged as described above, the semiconductor laser device with the protection circuit for monitoring the current flowing through the semiconductor laser diode 2 can be constructed with three terminals, and the terminal compatibility with the existing semiconductor laser device can be achieved. Can be secured. Further, although the semiconductor laser diode 2 and the transistor 5 are arranged and formed on the common electrode 13, a semiconductor assembling process can be used for this arrangement and formation, which facilitates manufacturing. Furthermore, since each element is installed in a plane, wiring can be facilitated by bonding. This is a drawback of the conventional CAN type semiconductor laser diode, that is, the lead terminal and the electrode surface of the semiconductor laser diode are orthogonal to each other, and it is difficult to perform wire bonding when the elements are combined. Since it is conductive, the disadvantage that the parts cannot be insulated and arranged as it is will be solved.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Name of item to be corrected] 0045

[Correction method] Change

[Correction content]

From the case 12, the three terminals 15, 1
6 and 17 are projected. The first terminal 15 is connected to the common electrode 13, and the second terminal 16 is disposed inside the case 1
6a is connected to the photodiode 11 by wire bonding, the in-case arrangement portion 17a of the third terminal 17 is connected to the emitter of the transistor 5 by wire bonding, and the second terminal 16 and the third terminal 17 are connected.
The resistor 3 is arranged on the resin region formed between the respective in-case arrangement portions 16a and 17a in and. One end of the resistor 3 is connected to the in-case arrangement portion 17a of the third terminal 17, and the other end of the resistor 3 is connected to the semiconductor laser diode 2 and the base of the transistor 5 by wire bonding.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Keiichi Yoshito 2-5-5 Keihan Hondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd.

Claims (8)

[Claims] 1. A resistor, which is connected in series to a semiconductor laser diode and extracts a voltage from a current flowing through the semiconductor laser diode, and a bypass path branched from a current supply path for supplying a current to the semiconductor laser diode, A semiconductor laser device with a protection circuit, comprising: a control element that controls a current flowing through a semiconductor laser diode by causing a current from a current supply path to flow in the bypass path based on a voltage value across the resistor. 2. The semiconductor laser device with a protection circuit according to claim 1, wherein the resistance includes a thermistor. 3. The control element comprises a transistor, the voltage across the resistor is applied between the base and the emitter of the transistor, and the bypass path is formed between the collector and the emitter of the transistor. The semiconductor laser device with a protection circuit according to claim 1 or 2. 4. The control element comprises a thyristor,
3. The protection according to claim 1, wherein the voltage across the resistor is applied between the gate and the cathode of the thyristor, and the bypass path is formed between the anode and the cathode of the thyristor. Semiconductor laser device with circuit. 5. A current monitor line for monitoring a current flowing through the semiconductor laser diode, which is connected to a connection point between the base or gate of the control element, the resistor and the semiconductor laser diode. A semiconductor laser device with a protection circuit according to claim 3 or 4. 6. A semiconductor laser diode and a control element are arranged on a common electrode provided in a case, three terminals are projected from the case, a first terminal is connected to the common electrode, and a second terminal is connected. A wire bonding serving as a current monitor line is connected to a portion of the terminal arranged in the case, and a portion of the third terminal arranged in the case is connected to the collector or the anode of the control element by wire bonding.
6. The semiconductor laser device with a protection circuit according to claim 5, wherein the resistor is connected between each of the terminals arranged in the case and the third terminal arranged inside the case. 7. A photodiode for detecting the light quantity of the semiconductor laser diode by making the backward emission light of the semiconductor laser diode incident is provided with one end side thereof being connected to the current supply path. Claim 3 or 4
A semiconductor laser device with a protection circuit according to. 8. A semiconductor laser diode, a photodiode, and a control element are arranged on a common electrode provided in the case, three terminals are projected from the case, and a first terminal is connected to the common electrode. The portion of the second terminal disposed in the case is connected to the photodiode by wire bonding, the portion of the third terminal disposed in the case is connected to the collector or anode of the control element by wire bonding, and the second terminal is connected. And a third terminal, a resistor is disposed on a resin region formed between the in-case disposed portions of the case, and one end of the resistor is connected to the in-case disposed portion of the third terminal, and the other region of the resistor is connected. 8. The protection according to claim 7, wherein the end side is connected to the semiconductor laser diode and the base or gate of the control element by wire bonding, respectively. Semiconductor laser device with circuit.