JPH07287857A - Optical head, optical semiconductor element and optical information recording and reproducing device - Google Patents

Abstract

PURPOSE:To set the cut-off frequency on the upper limit of a band limiting means at lower than the oscillating frequency of a laser noise reduction means by inserting the band limiting means between a detecting means and a preamplifier. CONSTITUTION:The circuit in a detection system is composed of a signal detecting means 25 or a photodiode 38 as a laser output detecting means 26, a low-pass filter (band limiting means) 9 and a preamplifier 13. The photodiode 38 outputs a current proportional to a light quantity by the incidence of a laser beam, the current passes through the low-pass filter 9 and is subjected to current-voltage conversion in the preamplifier 13. Since respective wirings are brought near to each other and induction is coupled, thus, the higher frequencies of the laser noise reduction means 5 are leaked into the input part of the preamplifier 13 and cause the drift of the output. Consequently, by inserting the low-pass filter 9, high frequency leaked into the input part of the preamplifier 13 is removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an optical head of an optical recording / reproducing apparatus.

[0002]

2. Description of the Related Art FIG. 26 is an explanatory view showing the structure of a conventional general optical head. In the figure, the optical head further includes a semiconductor laser diode 57 that emits laser light, a collimator lens 56 that converts the laser light into parallel light, a prism 55 that converts the traveling direction of the laser light, and a traveling direction of the laser light. A flip-up mirror 20 that converts and guides the laser light to a recording medium, an objective lens 15 that converts the laser light into a convergent light and focuses the light on the recording medium, and a reflected light from the recording medium is received to receive a positional error of the objective lens. A signal detecting means 25 for extracting a signal or a recording information signal, a laser output detecting means 26 for detecting an output by receiving a part of the emitted light of the semiconductor laser diode, and a position of the objective lens 15 are changed, and on the recording medium. Focusing coil 17, tracking coil 18 and magnet 4 for controlling so as to focus on a target position, the objective lens Composed of the support spring 3 and support 2 is elastically supported. Further, the semiconductor laser diode 57 has a CAN structure and is attached in close contact with the shield case 7. A laser noise reduction means 5 is housed inside the shield case 7. The laser noise reduction means 5 is a high-frequency oscillator, which reduces the laser noise by superimposing a high-frequency current on the laser diode drive current to reduce the coherence of the laser light. Therefore, a high level of high frequency noise is radiated, but in the configuration of the present optical head, the laser noise reduction means 5 and the semiconductor laser diode 57 are electromagnetically sealed by the CAN of the shield case 7 and the semiconductor laser diode 57. And other circuits inside the optical head are the laser noise reducing means 5
And because it was placed at a position physically far from the line through which the high frequency flows, the high frequency noise leaks to the detection system,
Phenomena that caused other problems due to it were not so common.

In recent years, there has been proposed an optical head as shown in FIG. 27 in which a light emitting element and a light receiving element for laser light are integrated to realize simplification and miniaturization. 28 and 29 are explanatory diagrams showing the configurations of the lens holder 1 and the optical semiconductor element 22 which are one of the components of the optical head shown in FIG. Further, FIG. 30 is an explanatory diagram schematically showing the internal circuit of the optical head of FIG. The configuration of the present optical head will be described below with reference to the drawings.

First, in FIG. 27, the optical head comprises the lens holder 1, a support spring 3 that elastically supports the lens holder 1 and freely changes the position thereof, and a fixed end of the support spring 3, A column 2 that indirectly supports the lens holder 1, a magnet 4 that generates a magnetic field around the lens holder 1 to control the focus position, and a high frequency oscillator that superimposes a high frequency wave on a laser diode drive current to generate a laser beam. Laser noise reduction means 5 for reducing laser noise by reducing the coherence of the optical head, a circuit inside the optical head and a circuit outside the optical head without leaking the high frequency generated from the laser noise reduction means 5 to the outside of the optical head. To connect the feedthrough capacitor 6, the preamplifier 13, the substrate 8 on which the preamplifier 13 is mounted, the preamplifier and the inside of the lens holder 1. A line 10, a line 11 connecting the laser noise reducing means 5 and the inside of the lens holder 1, a line 12 connecting the laser noise reducing means 5 and the feedthrough capacitor 6, and the entire optical head is wrapped with a magnetic conductive material to electrically In addition, a shield case 7 for magnetically isolating the outside of the optical head from the inside of the optical head, and an opening formed in the shield case 7 for extracting laser light from the shield case 7 and at the same time reflecting light from a recording medium An exit window 16 leading to the lens holder 1, an objective lens 15 for focusing the laser light emitted inside the lens holder 1 on the recording medium, and an output line for taking out the output of the preamplifier to the outside of the optical head. 14, a slit 19 for drawing out the output line from the shield case 7. Although not shown in the figure, a focusing coil and a tracking coil are attached to the side surface of the lens holder 1. The functions of the magnet 4, the focusing coil, the tracking coil, and the support spring 3 control the position of the lens holder 1 so that the laser beam is focused on a target position on the recording medium.

FIG. 28 is an explanatory view showing the structure of the lens holder 1 shown in FIG. Also, FIG. 29 corresponds to FIG.
7 is an explanatory diagram showing a configuration of the optical semiconductor element in FIG. Inside the lens holder 1, there is provided an optical semiconductor device including a laser chip, a signal detecting means for detecting the reflected light from the optical recording medium, a laser output detecting means for monitoring the emitted light amount of the laser light from the laser chip, and the like. include.

27, 28 and 29, the laser light emitted from the optical semiconductor element passes through the emission window of the shield case 7 and is focused on the recording medium outside the optical head as described above. As a result, the reflected light again passes through the emission window and is incident on the signal detection means inside the lens holder 1. The output of the signal detecting means is connected to the preamplifier 13 by a line 10 connecting the preamplifier and the inside of the lens holder 1. The preamplifier 13
Converts the current output from the signal detecting means into a voltage and, if necessary, further calculates outputs of the plurality of signal detecting means and sends the outputs to the outside of the optical head.

FIG. 30 is an explanatory diagram showing a circuit of a conventional optical head. In the optical head of FIG. 27, the outputs of the signal detecting means 25 and the laser output detecting means 26 are connected to the preamplifier 13 as shown in the figure. Here, the preamplifier 13 and the signal detecting means 25, or the preamplifier 13 and the laser output detecting means 26 are directly connected without being limited in band. Therefore, if high frequency noise is mixed in the output of the signal detecting means 25 or the laser output detecting means 26 or other currents on the line connecting the optical semiconductor element and the preamplifier 13, they are generated. The preamplifier 13 is directly input to the preamplifier 13 as it is.

[0008]

By the way, inside the optical head shown in FIG. 27, a line for supplying a laser diode drive current to the laser chip, a line for taking out an output from the signal detecting means, and a line for outputting the laser output from the laser output detecting means. The lines from which the output of is extracted are close to each other. In particular, FIG.
In an optical semiconductor device such as shown in which the laser chip and the signal detection means or the laser output detection means are integrally formed on the same substrate, the laser chip, the signal detection means and the laser output detection means are close to each other. At the same time, it is in contact with the common of each detecting means through the insulating film on the wafer. Also, because of the wiring on the wafer,
A portion where a line for supplying a laser diode drive current, a line for taking out an output from the signal detecting means, a line for taking out an output from the laser output detecting means, etc. intersect each other through an insulating film. Therefore, it is inevitable that the laser chip and the signal detecting means are capacitively or inductively coupled. On the other hand, the laser noise reduction means is a high-frequency oscillator, and has a function of superimposing a high-frequency current on the laser diode drive current to reduce the coherence of laser light and thereby reduce laser noise. Therefore, a high-level high-frequency current flows through the laser chip 23 and the line that supplies the laser diode drive current to the laser chip.

As a result, the high frequency applied to the laser chip 23 leaks to the signal detecting means 25 and the laser output detecting means 26. The high-frequency current is useful for the laser chip to reduce laser noise, but when leaking to the signal detecting means or the laser output detecting means, it contributes as a noise source and causes various problems.

First, one of the problems is that when the laser noise reduction means is driven, the output of the signal detection means 25 after the preamplifier 13 drifts, and normal position control of the optical head cannot be performed. It is to end up.

31 and 32 are explanatory views for explaining how the drift occurs. The output of the signal detecting means is Vi, and the high frequency noise leaking from the laser noise reducing means is vi. Normally, in an optical disk device, laser noise is not a problem during writing operation,
The semiconductor laser diode is driven by a constant current with a direct current. On the other hand, at the time of read operation, S /
Since the N ratio is required, the laser noise reducing means 5 mounted on the optical head is turned on to superimpose a high frequency on the preamplifier 13 laser diode drive current. If the high frequency leaks to the output of the signal detecting means, the preamplifier receives a current in which vi is superimposed on vi. If the noise component contained in the output of the signal detecting means is sufficiently smaller than the output of the signal detecting means, the Vi + vi does not exceed the allowable input of the preamplifier, and thus the preamplifier becomes a linear element. , The waveform is output without distortion. Further, generally, in a signal processing circuit of an optical disk device, a low-pass circuit that allows only a band necessary for reading information is inserted.
The bandwidth of the low pass circuit is sufficiently lower than the oscillation frequency of the laser noise reduction means. In addition, since the output bandwidth of the preamplifier is sufficiently lower than the oscillation frequency of the laser noise reduction means, the output signal of the laser noise reduction means functions similarly to the low-pass circuit.
Therefore, even if the high frequency originally emitted from the laser noise reduction means leaks and is input to the preamplifier, the high frequency is removed by the bandpass of the low-pass circuit or the preamplifier, It is possible to obtain a normal value of the signal detecting means output (FIG. 28). At this time, as a matter of course, the output signal of the preamplifier does not drift when the laser noise reduction means is turned on / off.

However, if the high frequency signal has a magnitude exceeding the allowable input level of the preamplifier, or if there is a non-linear or directional element in the process of the high frequency signal leaking to the preamplifier, The waveform of the high frequency signal is distorted, and asymmetry occurs with respect to the DC potential Vi. Generally, when an AC signal passes through the low-pass circuit, a DC component corresponding to its integrated value is generated. If the AC component vi has a positive / negative symmetrical waveform with respect to the DC potential Vi, the integrated value is canceled by the positive side and the negative side even when passing through the low-pass circuit, so that the DC component does not occur, but the positive / negative asymmetry. If so, a DC component corresponding to the integral value that has not been canceled is generated and superimposed on Vi (FIG. 29). This appears as a drift in the output signal of the preamplifier. As a result, in the conventional optical head, the O of the laser noise reducing means is reduced.
Since the position error signal of the optical head drifts due to N / OFF, there is a problem in that it is difficult to control the correct position of the optical head.

Next, another problem is that the output of the laser output detecting means after the preamplifier drifts when the laser noise reducing means is driven. This is due to the same phenomenon as the drift of the position error signal. As a result, the conventional optical head has a problem that an error occurs in the laser output detection due to the ON / OFF of the laser noise reduction means, making it impossible to perform accurate laser output control.

Furthermore, another problem is that when the laser noise reducing means is driven, the operation of the preamplifier becomes unstable due to the leaked high frequency, and in some cases, the oscillation of the preamplifier may be suppressed. It is to induce. When the preamplifier oscillates and a signal having an unnecessary frequency is output, the position control of the optical head becomes unstable, and the quality of the reproduction signal in the optical information recording / reproducing apparatus deteriorates, and There was a problem that it became impossible to read out or made an error.

The phenomena related to the above-mentioned three problems are the optical semiconductor elements in which the laser chip 23, the signal detecting means 25, and the laser output detecting means 26 are integrated as shown in FIG. This is particularly noticeable in the optical head using the. The reason for this is that by highly miniaturizing the optical head, the signal detecting means 25 and the laser output detecting means 26 come close to the laser chip 23 and the lines around the laser chip 23, and high frequencies easily leak from there. However, at the same time, the greatest advantage of the optical head using the optical semiconductor element is that it is small and has a simple structure. Therefore, it may be impossible to realize such a small-sized optical head without solving this problem. Also,
The amount of the drift depends on the magnitude of the output of the laser noise reducing means which is a high frequency oscillator, but in order to sufficiently obtain the laser noise reducing effect, the amount of drift of an optical head using the laser noise reducing means is relatively large. In that case, the drift amount becomes very large. Therefore, this problem is an important issue that must be overcome.

[0016]

The optical head according to the present invention comprises: (1) a laser chip, a signal detecting means for detecting the reflected light from the optical recording medium, or a laser for monitoring the light quantity of the laser light emitted from the laser chip. Output detection means or both, a preamplifier for amplifying the output of the signal detection means or the laser output detection means, or both, superimposing a high frequency on the laser diode drive current to reduce the coherence of laser light. In the light source unit including the laser noise reducing means for reducing the laser noise, the band limiting means is inserted between at least one of the detecting means and the preamplifier, and the upper limit of the pass band of the band limiting means is set. The cutoff frequency is set sufficiently lower than the oscillation frequency of the laser noise reduction means.

(2) In the optical head according to the first aspect, a band limiting means is inserted between the signal detecting means and the preamplifier, and the upper limit cutoff of the pass band of the band limiting means. Frequency is well above the signal band,
Further, it is characterized in that it is set sufficiently lower than the oscillation frequency of the laser noise reduction means.

(3) In the optical head according to the second aspect, the band limiting means has a characteristic of reducing the high frequency leaked from the laser noise reducing means to a level smaller than the allowable input level of the preamplifier. Characterize.

(4) In the optical head described in the item (1), band limiting means is inserted between the laser output detecting means and the preamplifier, and the upper limit of the pass band of the band limiting means is cut. The off frequency is set to be sufficiently higher than the band for controlling the laser output and sufficiently lower than the oscillation frequency of the laser noise reduction means.

(5) In the optical head according to the fourth aspect, the band limiting means has a characteristic of reducing the high frequency leaked from the laser noise reducing means to a level smaller than the allowable input level of the preamplifier. Characterize.

(6) In the optical head according to the first aspect, a band limiting means is inserted between the preamplifier and a bias power supply supplied to the signal detecting means or the laser output detecting means or both of them. Further, the upper limit cutoff frequency of the pass band of the band limiting means is set sufficiently lower than the oscillation frequency of the laser noise reducing means.

(7) In the optical head according to the sixth aspect, the band limiting means has a characteristic of reducing the high frequency leaked from the laser noise reducing means to a level smaller than the allowable input level of the preamplifier. Characterize.

(8) In the optical head according to the first aspect, band limiting means is inserted between the ground terminals of the signal detecting means and / or the laser output detecting means or both of them and the ground terminal of the preamplifier. In addition, the upper limit cutoff frequency of the pass band of the band limiting means is set sufficiently lower than the oscillation frequency of the laser noise reducing means.

(9) In the optical head as described in Item 8, the band limiting means has a characteristic of reducing the high frequency leaked from the laser noise reducing means to a level smaller than the allowable input level of the preamplifier. Characterize.

(10) In the optical head described in item 1,
The band limiting means is a coil component inserted between the preamplifier and the signal detecting means or the laser output detecting means.

(11) In the optical head described in item 1,
2. The light according to claim 1, wherein the band limiting unit is a magnetic block installed so as to cover a signal line connecting the preamplifier and the signal detecting unit or the laser output detecting unit. head.

(12) In the optical head described in item 1,
The band limiting means is a magnetic material applied to a signal line connecting the preamplifier and the signal detecting means or the laser output detecting means.

(13) In the optical head described in item 1,
The band limiting means is characterized in that a wiring pattern on a substrate connecting the preamplifier and the signal detecting means or the laser output detecting means is given a specific shape to have frequency characteristics.

(14) A laser chip, signal detection means for detecting reflected light from an optical recording medium, laser output detection means for monitoring the light quantity of laser light emitted from the laser chip, or both, and the signal detection means or A preamplifier that amplifies the output of the laser output detection means or both, and superimposes a high frequency on the laser diode drive current,
In a light source unit including a laser noise reducing unit that reduces laser noise by reducing coherence of laser light, the laser chip and the signal detecting unit, the laser output detecting unit, or both are configured on the same substrate. And a band limiting means is inserted between at least one of each said detecting means and the preamplifier,
Further, the cutoff frequency at the upper limit of the pass band of the band limiting means is set sufficiently lower than the oscillation frequency of the laser noise reducing means, and the high frequency leaked from the laser noise reducing means is set at the allowable input level of the preamplifier. It is characterized by having the property of reducing to a smaller level.

(15) Laser chip, signal detecting means for detecting reflected light from the optical recording medium, laser output detecting means for monitoring the amount of laser light emitted from the laser chip, the signal detecting means and the laser. A light source unit comprising a preamplifier for amplifying the output of the output detection means, and a laser noise reduction means for reducing laser noise by superimposing a high frequency on the laser diode drive current to reduce the coherence of the laser light. A laser chip, the signal detecting means, and an optical semiconductor element in which the laser output detecting means is formed on the same silicon wafer are provided, and one coil component is provided between each detecting means and the preamplifier. Further, the coil component is arranged so that the high frequency leaked from the laser noise reducing means is higher than the allowable input level of the preamplifier. And having the property of reduced to small level.

The optical semiconductor element of the present invention is (16) a laser chip and a signal detecting means for detecting the reflected light from the optical recording medium or a laser output detecting means for monitoring the light quantity of the laser light emitted from the laser chip. Or both, a preamplifier for amplifying the output of the signal detection means or the laser output detection means or both, and a laser by driving a high frequency on the laser diode drive current to reduce the coherence of the laser light. In a light source unit including laser noise reduction means for reducing noise, the laser chip and the signal detection means or the laser output detection means or both are formed on the same substrate, and at least one of the detection means is provided. Band limiting means is inserted between the output terminal and the output terminal, and the upper limit of the pass band of the band limiting means. The cut-off frequency is set to be sufficiently lower than the oscillation frequency of the laser noise reduction means.

(17) In the optical semiconductor device as described in Item 16, band limiting means is inserted between the signal detecting means and the preamplifier, and the upper limit of the pass band of the band limiting means is cut. The off frequency is set to be sufficiently higher than the signal band and sufficiently lower than the oscillation frequency of the laser noise reduction means.

(18) In the optical semiconductor device as described in Item 17, the band limiting means has a characteristic of reducing the high frequency leaked from the laser noise reducing means to a level smaller than the allowable input level of the preamplifier. Is characterized by.

(19) In the optical semiconductor device as described in Item 16, band limiting means is inserted between the laser output detecting means and the preamplifier, and the upper limit of the pass band of the band limiting means is set. The cutoff frequency is set to be sufficiently higher than the band for controlling the laser output and sufficiently lower than the oscillation frequency of the laser noise reduction means.

(20) In the optical semiconductor device as described in Item 19, the band limiting means has a characteristic of reducing the high frequency leaked from the laser noise reducing means to a level lower than the allowable input level of the preamplifier. Is characterized by.

(21) In the optical semiconductor element as described in Item 16, band limiting means is inserted between the bias power supply supplied to the signal detecting means and / or the laser output detecting means or both of them and the preamplifier. Further, the upper limit cutoff frequency of the pass band of the band limiting means is set sufficiently lower than the oscillation frequency of the laser noise reducing means.

(22) In the optical semiconductor element described in the twenty-first item, the band limiting means has a characteristic of reducing the high frequency leaked from the laser noise reducing means to a level smaller than the allowable input level of the preamplifier. Is characterized by.

(23) In the optical semiconductor device as described in Item 16, band limiting means is inserted between the ground terminal of the signal detecting means or the laser output detecting means or both of them and the ground terminal of the preamplifier. Further, the upper limit cutoff frequency of the pass band of the band limiting means is set sufficiently lower than the oscillation frequency of the laser noise reducing means.

(24) In the optical semiconductor device as described in Item 23, the band limiting means has a characteristic of reducing the high frequency leaked from the laser noise reducing means to a level smaller than the allowable input level of the preamplifier. Is characterized by.

(25) In the optical semiconductor element as described in Item 16, the band limiting means is a coil component inserted between the preamplifier and the signal detecting means or the laser output detecting means. Is characterized by.

(26) In the optical semiconductor device as described in Item 16, the band limiting means is installed so as to cover the signal line connecting the preamplifier and the signal detecting means or the laser output detecting means. It is a magnetic block.

(27) In the optical semiconductor device as described in Item 16, the band limiting means is a magnetic material applied to a signal line connecting the preamplifier and the signal detecting means or the laser output detecting means. It is characterized by

(28) In the optical semiconductor device as described in Item 16, the band limiting means has a specific shape in a wiring pattern on a substrate connecting the preamplifier and the signal detecting means or the laser output detecting means. It is characterized by being applied and having frequency characteristics.

The optical information recording / reproducing apparatus of the present invention is characterized in that the optical head described in (29) item 1 is used as a light source.

(30) The optical head described in the item 15 is used as a light source.

(31) An optical semiconductor element as described in item 16 is used as a light source.

[0047]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings. In the drawings, the same numbers are used for the same contents. The operation of the optical head of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory view showing the structure of an optical head in one embodiment of the present invention. The optical head includes a lens holder 1, a support spring 3 that elastically supports the lens holder 1 and can freely change its position, and a fixed end of the support spring 3 that supports the lens holder 1 indirectly. 2. A magnet 4 for controlling a focus position by generating a magnetic field around the lens holder 1, a high-frequency oscillator, which is a laser diode driving current superposed with a high frequency to reduce the coherence of laser light. A laser noise reducing means 5 for reducing noise, a feedthrough capacitor 6 for connecting a circuit inside the optical head and a circuit outside the optical head without leaking a high frequency generated from the laser noise reducing means 5 to the outside of the optical head, a preamplifier. 13, low-pass filter 9, substrate 8 on which the preamplifier 13 and the low-pass filter 9 are mounted, the preamplifier and the inside of the lens holder 1. A connecting line 10, a line 11 connecting the laser noise reducing means 5 and the inside of the lens holder 1, a line 12 connecting the laser noise reducing means 5 and the feedthrough capacitor 6, and the entire optical head is wrapped with a magnetic conductive material, A shield case 7 that electrically and magnetically isolates the outside of the optical head from the inside of the optical head, and an opening formed in the shield case 7 for extracting laser light from the shield case 7 and at the same time reflecting light from a recording medium. An exit window 16 for guiding the laser beam to the lens holder 1, an objective lens 15 for focusing a laser beam emitted inside the lens holder 1 on the recording medium,
It is composed of an output line 14 for taking out the output of the preamplifier to the outside of the optical head and a slit 19 for taking out the output line from the shield case 7. Although not shown in the figure, a focusing coil and a tracking coil are attached to the side surface of the lens holder 1. The functions of the magnet 4, the focusing coil, the tracking coil, and the support spring 3 control the position of the lens holder 1 so that the laser beam is focused on a target position on the recording medium.

As will be shown later in FIG. 2, the lens holder 1
An optical semiconductor element including a laser chip, a signal detecting means for detecting a reflected light from the optical recording medium, a laser output detecting means for monitoring the amount of laser light emitted from the laser chip, and the like is included inside. . The laser light emitted from the optical semiconductor element is applied to the shield case 7 as described above.
The light is focused on the recording medium outside the optical head through the emission window, and the reflected light again enters the signal detection means inside the lens holder 1 through the emission window. The output of the signal detecting means is the preamplifier and the lens holder 1.
It is connected to the preamplifier 13 by a line 10 connecting the inside. The preamplifier 13 converts the current output from the signal detecting means into a voltage and, if necessary, further calculates the outputs of the plurality of signal detecting means and sends it to the outside of the optical head.

The low-pass filter 9 according to the present invention is attached to the input part of the preamplifier 13. In the figure, the low-pass filter 9 uses a small coil component. Here, the cutoff frequency of the low-pass filter 9 is set sufficiently higher than the signal band of the signal detection means and sufficiently lower than the oscillation frequency of the laser noise reduction means. As a result, the low-pass filter has an attenuation rate of 10 dB or more with respect to the signal band at the oscillation frequency of the laser noise reduction means. The output of the signal detecting means includes an unnecessary high frequency component generated from the laser noise reducing means 5. However, in the present embodiment, most of the high frequency components are removed by the action of the low pass filter 9 and are not input to the preamplifier. On the other hand, the original output of the signal detecting means passes through the low pass filter 9 without loss,
Since it can reach the preamplifier 13, it does not impair the performance of the conventional optical head in which the low-pass filter 9 is not mounted. With this function, when the laser noise reduction means is turned on, the output of the preamplifier of the signal detection means drifts, and the problem in the conventional optical head that the correct control of the optical head is disturbed can be improved. it can. The operation of the low pass filter 9 will be described later in detail.

FIG. 2 is an explanatory view showing the structure of the lens holder 1 in the embodiment of FIG. Further, FIG. 3 is an explanatory diagram showing the details of the laser unit 12 in FIG. The operation of the lens holder 1 and the optical semiconductor element 22 in this embodiment will be described below with reference to FIGS. 2 and 3. 2 is the same as FIG. 28, and FIG.
Is the same as FIG. 29.

The lens holder 1 includes an optical semiconductor element 2
2, diffractive means 21, objective lens 15, flip-up mirror 2
0, focusing coil 17, tracking coil 1
It consists of eight. Further, the optical semiconductor element 22 is for detecting the amount of light emitted from the laser chip 23, the reflection surface 24, the signal detection means for reproducing the recording information and the position error signal from the reflection light from the recording medium, and the light emission amount from the laser chip 23. A wafer 27, a polarizing plate 28, the laser chip 23, and a lead terminal 29 for connecting an external circuit with the laser output detecting means 26 integrated on the same substrate.
Consists of The laser light emitted from the laser chip 23 in the direction parallel to the surface of the wafer 27 is reflected by the reflection surface 2
The direction of travel is changed by 90 ° at 4 and is emitted in the normal direction of the wafer 27. After that, the laser light is transmitted to the diffraction means 2
After passing 1, the traveling direction can be further changed to the optical axis direction of the objective lens 15 by the flip-up mirror 24. Then, the light enters the objective lens 15 and is focused on the recording medium.

On the other hand, the reflected light from the recording medium passes through the objective lens 15 and is guided to the diffracting means 21 by the flip-up mirror 20. Further, due to the function of the diffracting means 21, the reflected light is condensed on the signal detecting means 25 inside the optical semiconductor element 22 with astigmatism. In the signal detecting means, light energy is converted into electric current.
Finally, the focus error signal, the track error signal, and the recording information signal can be generated by electrically calculating the output of the signal detecting means as needed.

Although not shown in the figure, the optical semiconductor element 22 is sealed with a transparent sealing member in the emitting direction. The laser light emitted from the laser chip 23 must pass through the transparent sealing member before reaching the diffracting means 21. At this time, a part of the laser light is reflected on the wafer 27, and the laser output detecting means 2
6 is incident. Since the amount of light incident on the laser output detector is proportional to the amount of light emitted from the laser chip 23, the amount of light emitted from the laser chip 23 can be monitored from the output of the laser output detector 26.

On the side surface of the lens holder 1, a focusing coil 17 for moving the lens holder 1 in the focus direction and the lens holder 1 in the track direction are provided.
A tracking coil 18 for moving is attached. If the lens holder 1 is placed in a magnetic field, the position of the lens holder 1 can be changed by supplying a driving current to the focusing coil 17 and the tracking coil 18. That is, the focus position control and the track position control of the detection spot for detecting information from the recording medium can be performed. As a result, the optical head has a function of always forming an optimum laser beam spot on the recording medium, and moving the spot to a target position on the recording medium at some time.

FIG. 4 is a block diagram showing the structure of the optical head according to this embodiment. The electrical operation of the optical head will be described below with reference to the drawings. First, the laser diode drive current 30 is supplied through the feedthrough capacitor 6. Although this is a direct current, a high frequency current output from the laser noise reduction means 5 is further superimposed and supplied to the laser chip 23. Most of the optical output of the laser chip 23 is guided to the recording medium, but part of the optical output directly enters the laser output detection means 26 and is converted into a laser output detection signal. Further, the reflected light from the recording medium enters the signal detecting means and is also converted into an electric signal.

By the way, a high level high frequency current is passed through the laser chip 23 by the action of the laser noise reduction means 5. Here, inside the optical head, a line for supplying a laser diode drive current to the laser chip, a line for taking out an output from the signal detecting means,
The lines for taking out the output from the laser output detecting means are close to each other. Further, in an optical semiconductor device such as shown in FIG. 3 in which a laser chip and a signal detecting means or a laser output detecting means are integrally formed on the same substrate, the laser chip, the signal detecting means and the laser output detecting means are provided. The means are close to each other and, at the same time, are in contact with the common of each detection means via the insulating film on the wafer. Also, for convenience of wiring on the wafer, a line for supplying a laser diode drive current, a line for taking out an output from the signal detecting means, a line for taking out an output from the laser output detecting means, and the like are provided through an insulating film. Some parts intersect each other. Therefore, it is inevitable that the laser chip and the signal detecting means are capacitively or inductively coupled and the high frequency wave applied to the laser chip leaks to the signal detecting means.

The high-frequency current is useful for the laser chip to reduce laser noise, but when it leaks to the signal detecting means and the laser output detecting means, it contributes as a noise source and causes various problems. That is, when the laser noise reduction means is turned on, the position error signal of the optical head drifts, which causes a problem that correct control of the optical head becomes difficult. Therefore, in this embodiment, the high-frequency component is removed by using the low-pass filter 9, and only the original output of the signal detecting means is input to the preamplifier.

FIG. 5 is an explanatory view specifically showing the electrical circuit of the optical head according to the present invention. FIG. 6 is an explanatory diagram showing the frequency characteristics of the low pass filter 9 and its effect. It should be noted that a series of circuits originally composed of the signal detecting means 25, the low-pass filter 9 and the preamplifier 13 exist in a plurality of systems depending on the light receiving system of the optical head.
However, for simplification, only one system is shown here as a representative. Hereinafter, the operation of the low-pass filter 9 will be described in detail with reference to FIGS.

First, the circuit of the light emission system is composed of the laser noise reduction means 5 and the laser chip 23. The laser noise reduction means 5 comprises a high frequency oscillator 43, a coil 41 and a capacitor 42. The high frequency generated by the high frequency oscillator 43 passes through the capacitor 42 and is supplied to the laser chip 23. Although the laser diode drive current 33 is supplied from the outside, the coil 41 and the feedthrough capacitor 6 serve to form a circuit so that the high frequency does not leak to the outside of the optical head. A current in which the output of the high frequency oscillator 43 and the laser diode drive current 33 are superimposed flows through the laser chip 23. Next, the circuit of the detection system includes a photodiode 38 which is the signal detection means 25 or the laser output detection means 26, the low pass filter 9,
It is composed of the preamplifier 13. The photodiode 38 outputs a current proportional to the amount of light when laser light is incident. The current passes through the low-pass filter 9 and is current-voltage converted by the preamplifier 13. The problem here is that since the laser chip 23 and the photodiode 38 are on the same wafer as shown in FIG. 3, the laser chip 23 and the connecting line thereof and the photodiode 38 and the connecting line thereof are present. Is that they are capacitively coupled to each other due to their structure. The capacitances are shown as a stray capacitance C1 (34) and a stray capacitance C2 (35) in the figure. In addition, since the lines are close to each other inside the optical head, inductive coupling also exists. As a result, the high frequency of the laser noise reduction means 5 leaks to the input part of the preamplifier 13 and causes output drift or the like. In this embodiment, by inserting the low pass filter 9,
The high frequency leaking to the input part of the preamplifier 13 is removed.

The frequency characteristic of the low-pass filter 9 is shown in FIG. 6 (a). As described above, the low pass filter 9
The cutoff frequency is set to be sufficiently higher than the signal band of the signal detecting means and sufficiently lower than the oscillation frequency of the laser noise reducing means. As a result, the low-pass filter has a characteristic that it has a large loss with respect to an unnecessary high-frequency component included in the output of the signal detecting means and has almost no loss with respect to the output of the signal detecting means 25. . Due to this action, most of the high frequency components are removed by the low pass filter 9 and are not input to the preamplifier. On the other hand, the original output of the signal detecting means can pass through the low pass filter 9 without loss and reach the preamplifier 13.
By inserting the low-pass filter 9, the output of the preamplifier of the signal detecting means drifts when driving the laser noise reducing means, which has been a problem in the conventional optical head, and the correct control of the optical head is impeded. It is possible to improve the phenomenon of being performed.

Regarding this point, FIG. 6B and FIG.
This will be described in detail with reference to (c). First, the case where the low-pass filter is not used will be described with reference to FIG. As described above, the high frequency noise leaks to the output of the signal detecting means. The level varies greatly depending on the structure of the optical semiconductor element, but for example, an amplitude of 10
It is assumed that high-frequency noise of [μA] is included (1).
Here, to be precise, the illustrated high-frequency noise has a complex waveform that is modulated by the input signal current, but the input signal current is ii (constant) for simplicity. On the other hand, in recent years, along with the reduction in power consumption of optical heads, a single power supply low voltage drive amplifier is often used as the preamplifier. Generally, the allowable input current range of the amplifier is wide in the negative direction but very narrow in the positive direction with respect to the midpoint potential. If the allowable input current in the positive direction is 7 [μA] and the waveform is abruptly distorted when the allowable input current is exceeded, the output of the signal detecting means is
The waveform in the positive direction is clipped at the first stage of the preamplifier (2). Since the oscillation frequency of the laser noise reduction means is sufficiently higher than the band of the pre-amplifier rear stage or the detection system circuit thereafter, it is finally integrated into a direct current component. As explained in the section of conventional technology,
If positive and negative symmetry with respect to the midpoint potential, positive and negative components cancel each other out after integration, so that no DC component eventually occurs. However, in the case of the positive / negative asymmetrical waveform as shown in the figure, the positive / negative components cannot cancel each other out, and a DC component corresponding to the time average of the clipped area is generated after integration. The current value is about 0.46 [μA] under the above conditions, and the output of the preamplifier of the signal detecting means will drift (3). On the other hand, since the amplitude of the output current of the signal detecting means in this embodiment is about 2 [μA], the drift current reaches 23% of the required signal current. As a result, the optical head position detection signal synthesized by the signal detecting means has an incorrect value, which hinders position control. In addition, the output current of the laser output detecting means in the present embodiment is about 30 [μA / mW], and the drift current corresponds to about 5% thereof when emitting 0.3 [mW]. This results in a non-negligible laser power error.

Next, the case of using the low-pass filter will be described with reference to FIG. It is assumed that the output of the signal detecting means includes high-frequency noise having an amplitude of 10 [μA] as described above (1). Here, the low-pass filter having the characteristic of attenuating the high frequency noise to a level not exceeding the allowable input of the preamplifier is inserted between the signal detecting means and the preamplifier. For example, with a filter having a loss of 15 [dB] at the oscillation frequency of the laser noise reduction means, the high frequency noise can be suppressed to about 1.8 [μA]. The allowable input current of the preamplifier is the same 7
If it is [μA], the waveform of the high frequency noise will not be distorted (2). That is, even if integrated in the circuit of the detection system after that, since the positive and negative components are symmetrical with respect to the midpoint potential, the positive and negative components cancel each other out, and the direct current component does not occur. As described above, by inserting an appropriate low-pass filter between the signal detection means and the preamplifier, it is possible to prevent output drift when driving the laser noise reduction means (3).

FIGS. 7A, 7B, 7C and 7D show concrete examples of the low pass filter 9.
FIG. 7A shows a first-order filter using a single coil component, which is a simple and low-cost low-pass filter 9
Can be formed. Further, in the small-sized optical head as in the present embodiment, it is a great advantage that the component space is not required so much. FIG. 7B shows each 1
It is a secondary filter consisting of individual coils and capacitors. In this case, it is possible to form a filter having a larger attenuation ratio than the embodiment of FIG. Figure 7 (c)
Is a third-order filter consisting of one coil and two capacitors. In this case, it is possible to form a filter having steeper characteristics than the embodiment of FIG. Figure 7
(D) 3 consisting of 2 coils and 1 capacitor
The next filter. In this case, a filter having the same steepness as that of the embodiment of FIG. 7C can be formed, but the impedance seen from the preamplifier 13 side becomes large, which may cause increase in amplifier noise. There is no.

As described above, in the present embodiment, since the occurrence of the above-mentioned problem due to the leakage of high frequency from the laser noise reduction means 5 is prevented, the structure is small and the structure is simplified by utilizing the characteristics of the optical semiconductor element. It is possible to realize a simple optical head.
Further, even if the laser noise reducing means having a relatively large output is used for the optical head in order to sufficiently obtain the laser noise reducing effect, the drift amount becomes very small, so that the conventional performance is not deteriorated and the drift amount is reduced. It is possible to provide a noise optical head.

(Embodiment 2) FIG. 8 is an explanatory view showing the structure of an optical head in one embodiment of the present invention. The optical head of this embodiment includes a lens holder 1, a support spring 3 that elastically supports the lens holder 1 and freely changes its position,
A support 2 that is a fixed end of the support spring 3 and indirectly supports the lens holder 1, a magnet 4 that generates a magnetic field around the lens holder 1 to control the focus position, a high-frequency oscillator, and a laser. Laser noise reducing means 5 for reducing laser noise by superimposing a high frequency on the diode drive current to reduce the coherence of laser light, and without leaking the high frequency generated from the laser noise reducing means 5 to the outside of the optical head. Feedthrough capacitor 6 for connecting a circuit inside the optical head and a circuit outside the optical head, a preamplifier 13, a low-pass filter 9, a substrate 8 on which the preamplifier 13 and the lowpass filter 9 are mounted, the preamplifier and the lens A line 10 connecting the inside of the holder 1, a line 11 connecting the laser noise reduction means 5 and the inside of the lens holder 1,
The wire 12 connecting the laser noise reduction means 5 and the feedthrough capacitor 6 and the entire optical head are wrapped with a magnetic conductive material,
A shield case 7 that electrically and magnetically isolates the outside of the optical head from the inside of the optical head, and an opening formed in the shield case 7 for extracting laser light from the shield case 7 and at the same time reflecting light from a recording medium. To the lens holder 1, an objective window 15 for focusing the laser light emitted in the lens holder 1 on the recording medium, and an output of the preamplifier to the outside of the optical head. The output line 14 and the slit 19 for pulling out the output line from the shield case 7 are formed. Although not shown in the figure, a focusing coil and a tracking coil are attached to the side surface of the lens holder 1. By the functions of the magnet 4, the focusing coil, the tracking coil, and the support spring 3, the position of the lens holder 1 is controlled so that the laser beam is focused on a target position on the recording medium.

Although not shown in FIG. 8, inside the lens holder 1, a laser chip, a signal detecting means for detecting the reflected light from the optical recording medium, and an amount of laser light emitted from the laser chip are monitored. It includes an optical semiconductor element including a combination of laser output detecting means and the like.

A part of the laser light emitted from the optical semiconductor element is reflected inside the optical semiconductor element and enters the laser output detecting means 26. The output of the laser output detecting means 26 is connected to the preamplifier 13 by a line 10 connecting the preamplifier and the inside of the lens holder 1. The preamplifier 13 includes the laser output detecting means 2
The current output from 6 is converted into a voltage and, if necessary, further amplified and sent out to the outside of the optical head.

The low-pass filter 9 according to the present invention is attached to the input part of the preamplifier 13. Here, the cutoff frequency of the low-pass filter 9 is set sufficiently higher than the control band of the laser output and sufficiently lower than the oscillation frequency of the laser noise reduction means. The output of the laser output detecting means 26 contains an unnecessary high frequency component generated from the laser noise reducing means 5. However, in the present embodiment, most of the high frequency components are removed by the action of the low pass filter 9 and are not input to the preamplifier. On the other hand, the original output of the laser output detecting means 26 can pass through the low-pass filter 9 without loss and reach the preamplifier 13, so that the conventional optical head not equipped with the low-pass filter 9 is provided. Does not impair the performance of.

Regarding this point, FIG. 6B and FIG.
An explanation will be given using (c). First, the case where the low-pass filter is not used will be described with reference to FIG. As described above, high frequency noise leaks to the output of the laser output detecting means. The level varies greatly depending on the structure of the optical semiconductor element, but for example, an amplitude of 10
It is assumed that high-frequency noise of [μA] is included (1).
If the allowable input current in the positive direction of the preamplifier is 7 [μA] and the waveform is abruptly distorted when the allowable input current is exceeded, the output of the laser output detecting means is at the first stage of the preamplifier. The waveform in the positive direction is clipped (2). The oscillation frequency of the laser noise reduction means is
Since it is sufficiently higher than the band of the detection amplifier circuit after the preamplifier or after the preamplifier, it is finally integrated into a direct current component. As described above, if the positive and negative symmetry with respect to the midpoint potential, no DC component is generated, but in the case of positive and negative asymmetric waveforms as shown in the figure, the positive and negative components cannot cancel each other and the time of the area clipped after integration is A DC component corresponding to the average is generated. The current value is about 0.46 [μ under the above conditions.
A], and the output of the preamplifier of the laser output detecting means drifts (3). On the other hand, the output current of the laser output detecting means in this embodiment is 30.
It is about [μA / mW], and the drift current corresponds to about 5% thereof at the time of emission of 0.3 [mW]. This results in a non-negligible laser power error.

Next, the case of using the low-pass filter will be described with reference to FIG. The output of the laser output detecting means has an amplitude of 10 [μA] as described above.
It is assumed that the high frequency noise of (1) is included. here,
As the low-pass filter, a filter having a characteristic of attenuating the high-frequency noise to a level not exceeding an allowable input of the preamplifier is inserted between the laser output detecting means and the preamplifier. For example, in the case of a filter having a loss of 15 [dB] at the oscillation frequency of the laser noise reduction means, the high frequency noise is reduced to about 1.8 [μ].
A] can be suppressed. If the allowable input current of the preamplifier is the same 7 [μA], the waveform of the high frequency noise will not be distorted (2). That is, even if integrated in the circuit of the detection system after that, since the positive and negative components are symmetrical with respect to the midpoint potential, the positive and negative components cancel each other out, and the direct current component does not occur. As described above, by inserting an appropriate low-pass filter between the laser output detecting means and the preamplifier, it is possible to prevent output drift when driving the laser noise reducing means (3).

FIG. 9 is a block diagram showing the structure of the optical head according to this embodiment. Most of the optical output of the laser chip 23 is guided to the recording medium, but part of the optical output directly enters the laser output detection means 26 and is converted into a laser output detection signal. In the present embodiment, the laser output detecting means 2
A low pass filter 9 is inserted between 6 and the preamplifier 13. Thereby, the laser noise reduction means 5
Most of the high frequency component leaked from the laser is removed, and only the original output of the laser output detecting means 26 is input to the preamplifier. The phenomenon that the preamplifier output of the laser output detecting means 26 drifts when the laser noise reducing means is driven, which is a problem in the conventional optical head, and the correct control of the laser output is obstructed is improved. can do.

As described above, in the present embodiment, since the occurrence of the above problems due to the leakage of the high frequency from the laser noise reducing means 5 is prevented, the structure is small and the structure is simplified by making the best use of the characteristics of the optical semiconductor element. It is possible to realize a simple optical head.
Further, even if the laser noise reducing means having a relatively large output is used for the optical head in order to sufficiently obtain the laser noise reducing effect, the drift amount becomes very small, so that the conventional performance is not deteriorated and the drift amount is reduced. It is possible to provide a noise optical head. The other operations and configurations are shown in FIG.
The detailed description will be omitted because it is the same as that of the first embodiment.

(Embodiment 3) FIG. 10 is an explanatory view showing the structure of an optical head in one embodiment of the present invention. The optical head of this embodiment includes a lens holder 1, a support spring 3 that elastically supports the lens holder 1 and freely changes its position, and a fixed end of the support spring 3 that indirectly connects the lens holder 1. A supporting column 2, a magnet 4 that generates a magnetic field around the lens holder 1 to control the focus position, and a high-frequency oscillator that superimposes a high frequency on the laser diode drive current to reduce the coherence of laser light. By doing so, laser noise reducing means 5 for reducing laser noise, and a feedthrough capacitor 6 for connecting a circuit inside the optical head to a circuit outside the optical head without leaking the high frequency generated from the laser noise reducing means 5 to the outside of the optical head. , Preamplifier 13,
Low pass filter 9, substrate 8 on which the preamplifier 13 and the low pass filter 9 are mounted, line 10 connecting the preamplifier and the inside of the lens holder 1, laser noise reduction means 5 and the inside of the lens holder 1 are connected Line 1
1. The laser noise reduction means 5 and the feedthrough capacitor 6
A wire 12 that connects the optical head, a shield case 7 that wraps the entire optical head with a magnetic conductive material, and electrically and magnetically shields the outside of the optical head from the inside of the optical head, and an opening formed in the shield case 7. At the same time as taking out the laser light from the shield case 7, an exit window 16 for guiding the reflected light from the recording medium to the lens holder 1, and an objective lens for focusing the laser light emitted inside the lens holder 1 on the recording medium. 15, an output line 14 for taking out the output of the preamplifier to the outside of the optical head, and a slit 19 for taking out the output line from the shield case 7. Although not shown in the figure, a focusing coil and a tracking coil are attached to the side surface of the lens holder 1. By the functions of the magnet 4, the focusing coil, the tracking coil, and the support spring 3, the lens holder 1 is focused so that the laser light is focused on a target position on the recording medium.
The position of is controlled. Further, inside the lens holder 1, an optical semiconductor including a laser chip, a signal detecting means for detecting the reflected light from the optical recording medium, a laser output detecting means for monitoring the amount of laser light emitted from the laser chip, and the like are combined. The element is included.

The low-pass filter 9 according to the present invention is attached to the input part of the preamplifier 13. Here, the cutoff frequency of the low-pass filter 9 is sufficiently higher than the control band of the laser output between the laser output detection means 26 and the preamplifier 13 and sufficiently lower than the oscillation frequency of the laser noise reduction means. It is set. Also, the signal detecting means 25 and the preamplifier 1
During period 3, the frequency is set sufficiently higher than the signal band and sufficiently lower than the oscillation frequency of the laser noise reduction means. The outputs of the laser output detection means 26 and the signal detection means 25 include unnecessary high frequency components leaking from the laser noise reduction means 5. However, in the present embodiment, most of the high frequency components are removed by the action of the low pass filter 9 and are not input to the preamplifier. On the other hand, the laser output detecting means 26
The original output of the signal detecting means 25 can pass through the low-pass filter 9 without loss and reach the preamplifier 13, so that the performance of the conventional optical head not equipped with the low-pass filter 9 is improved. There is no loss. With this function, when the laser noise reduction means is turned on, the outputs of the preamplifiers of the laser output detection means 26 and the signal detection means 25 drift, and normal laser output control and optical head position control are hindered. It is possible to solve the problem of the conventional optical head.

Regarding this point, FIG. 6B and FIG.
This will be described in detail with reference to (c). First, the case where the low-pass filter is not used will be described with reference to FIG. As described above, high frequency noise leaks to the output of each of the detecting means. The level varies greatly depending on the structure of the optical semiconductor element, but for example, an amplitude of 10 [μ
It is assumed that the high frequency noise [A] is included (1). On the other hand, in recent years, along with the reduction in power consumption of optical heads, a single power supply low voltage drive amplifier is often used as the preamplifier. Generally, the allowable input current range of the amplifier is wide in the negative direction but very narrow in the positive direction with respect to the midpoint potential. If the allowable input current in the positive direction is set to 7 [μA] and the waveform is distorted abruptly when the allowable input current is exceeded, the output of each of the detection means has a waveform in the positive direction at the first stage of the preamplifier. It becomes a clipped shape (2). Since the oscillation frequency of the laser noise reduction means is sufficiently higher than the band of the pre-amplifier rear stage or the detection system circuit thereafter, it is finally integrated into a direct current component. As described in the section of the prior art, if the potential is positive and negative with respect to the midpoint potential, the positive and negative components cancel each other out after the integration, so that the direct current component does not occur. However, in the case of the positive / negative asymmetrical waveform as shown in the figure, the positive / negative components cannot cancel each other out, and a DC component corresponding to the time average of the clipped area is generated after integration. The current value is about 0.46 [μA] under the above conditions, and the output of the preamplifier of each of the detection means will drift (3). On the other hand, since the amplitude of the output current of the signal detecting means in this embodiment is about 2 [μA], the drift current reaches 23% of the required signal current. As a result, the optical head position detection signal synthesized by the signal detecting means has an incorrect value, which hinders position control. In addition, the output current of the laser output detecting means in the present embodiment is about 30 [μA / mW], and the drift current corresponds to about 5% thereof when emitting 0.3 [mW]. This results in a non-negligible laser power error.

Next, the case of using the low-pass filter will be described with reference to FIG. It is assumed that the output of each of the detecting means includes high-frequency noise having an amplitude of 10 [μA] as in the above (1). Here, as the low-pass filter, one having a characteristic of attenuating the high-frequency noise to a level not exceeding an allowable input of the preamplifier is inserted between each of the detecting means and the preamplifier. For example, with a filter having a loss of 15 [dB] at the oscillation frequency of the laser noise reduction means, the high frequency noise can be suppressed to about 1.8 [μA]. The allowable input current of the preamplifier is the same 7
If it is [μA], the waveform of the high frequency noise will not be distorted (2). That is, even if integrated in the circuit of the detection system after that, since the positive and negative components are symmetrical with respect to the midpoint potential, the positive and negative components cancel each other out, and the direct current component does not occur. As described above, by inserting an appropriate low-pass filter between each of the detection means and the preamplifier, it is possible to prevent output drift when driving the laser noise reduction means (3). Since the other operations and configurations are the same as those of the embodiment of FIG. 1, detailed description will be omitted.

FIG. 11 is a block diagram showing the structure of the optical head according to this embodiment. In this embodiment, the low-pass filter 9 is inserted both between the laser output detecting means 26 and the preamplifier 13 and between the signal detecting means 25 and the preamplifier 13. As a result, most of the high frequency components leaked from the laser noise reduction means 5 are removed. In the present embodiment, it is possible to realize an optical head that is small in size and has a simple structure, which makes it possible to perform normal laser output control and position control of the optical head even when the laser noise reduction means 5 is driven, making use of the characteristics of the optical semiconductor element. Further, even if the laser noise reducing means having a relatively large output is used for the optical head in order to sufficiently obtain the laser noise reducing effect, the drift amount becomes very small, so that the conventional performance is not deteriorated and the drift amount is reduced. It is possible to provide a noise optical head. Since the other operations and configurations are the same as those of the embodiment of FIG. 1, detailed description will be omitted.

(Embodiment 4) FIG. 12 is an explanatory view showing the structure of an optical head in one embodiment of the present invention. The optical head of this embodiment includes a lens holder 1, a support spring 3 that elastically supports the lens holder 1 and freely changes its position, and a fixed end of the support spring 3 that indirectly connects the lens holder 1. A supporting column 2, a magnet 4 that generates a magnetic field around the lens holder 1 to control the focus position, and a high-frequency oscillator that superimposes a high frequency on the laser diode drive current to reduce the coherence of laser light. By doing so, laser noise reducing means 5 for reducing laser noise, and a feedthrough capacitor 6 for connecting a circuit inside the optical head to a circuit outside the optical head without leaking the high frequency generated from the laser noise reducing means 5 to the outside of the optical head. , Preamplifier 13,
Low pass filter 9, substrate 8 on which the preamplifier 13 and the low pass filter 9 are mounted, line 10 connecting the preamplifier and the inside of the lens holder 1, laser noise reduction means 5 and the inside of the lens holder 1 are connected Line 1
1. The laser noise reduction means 5 and the feedthrough capacitor 6
A wire 12 that connects the optical head, a shield case 7 that wraps the entire optical head with a magnetic conductive material, and electrically and magnetically shields the outside of the optical head from the inside of the optical head, and an opening formed in the shield case 7. At the same time as taking out the laser light from the shield case 7, an exit window 16 for guiding the reflected light from the recording medium to the lens holder 1, and an objective lens for focusing the laser light emitted inside the lens holder 1 on the recording medium. 15, an output line 14 for taking out the output of the preamplifier to the outside of the optical head, and a slit 19 for taking out the output line from the shield case 7. Although not shown in the figure, a focusing coil and a tracking coil are attached to the side surface of the lens holder 1. By the functions of the magnet 4, the focusing coil, the tracking coil, and the support spring 3, the lens holder 1 is focused so that the laser light is focused on a target position on the recording medium.
The position of is controlled. Further, inside the lens holder 1, an optical semiconductor including a laser chip, a signal detecting means for detecting the reflected light from the optical recording medium, a laser output detecting means for monitoring the amount of laser light emitted from the laser chip, and the like are combined. The element is included.

A low-pass filter 9 according to the present invention is attached between a power supply line of a line 10 connecting the preamplifier and the inside of the lens holder 1 and a power supply terminal of the preamplifier 13. Here, the cutoff frequency of the low-pass filter 9 is set sufficiently lower than the oscillation frequency of the laser noise reduction means. The power supply line of the line 10 connecting the preamplifier and the inside of the lens holder 1 contains an unnecessary high frequency component leaked from the laser noise reduction means 5. However, in the present embodiment, most of the high frequency components are removed by the action of the low pass filter 9 and are not input to the power supply terminal of the preamplifier. On the other hand, the power supply to the inside of the lens holder is normally performed as usual. Due to this action, when the laser noise reduction means is driven, the outputs of the preamplifiers of the laser output detection means 26 and the signal detection means 25 drift, and normal laser output control and position control of the optical head are disturbed. It is possible to solve the problem of the conventional optical head. Since the other operations and configurations are the same as those of the embodiment of FIG. 1, detailed description will be omitted.

FIG. 13 is a circuit diagram showing the structure of the optical head according to this embodiment. In this embodiment, the low-pass filter 9 is inserted in the middle of the power supply line supplied to the common terminals of the laser output detecting means 26 and the signal detecting means 25. Thereby, the laser noise reduction means 5
Therefore, the high frequency component leaked to the laser output detecting means 26 and the signal detecting means 25 is removed and is not input to the preamplifier 13 through the power supply line.
In the present embodiment, it is possible to realize an optical head that is small in size and has a simple structure, which makes it possible to perform normal laser output control and position control of the optical head even when the laser noise reduction means 5 is driven, making use of the characteristics of the optical semiconductor element. Further, even if the laser noise reducing means having a relatively large output is used for the optical head in order to sufficiently obtain the laser noise reducing effect, the drift amount becomes very small, so that the conventional performance is not deteriorated and the drift amount is reduced. It is possible to provide a noise optical head.

(Embodiment 5) FIG. 14 is an explanatory view showing the structure of an optical head in one embodiment of the present invention. The optical head of this embodiment includes a lens holder 1, a support spring 3 that elastically supports the lens holder 1 and freely changes its position, and a fixed end of the support spring 3 that indirectly connects the lens holder 1. A supporting column 2, a magnet 4 that generates a magnetic field around the lens holder 1 to control the focus position, and a high-frequency oscillator that superimposes a high frequency on the laser diode drive current to reduce the coherence of laser light. By doing so, laser noise reducing means 5 for reducing laser noise, and a feedthrough capacitor 6 for connecting a circuit inside the optical head to a circuit outside the optical head without leaking the high frequency generated from the laser noise reducing means 5 to the outside of the optical head. , Preamplifier 13,
Low pass filter 9, substrate 8 on which the preamplifier 13 and the low pass filter 9 are mounted, line 10 connecting the preamplifier and the inside of the lens holder 1, laser noise reduction means 5 and the inside of the lens holder 1 are connected Line 1
1. The laser noise reduction means 5 and the feedthrough capacitor 6
A wire 12 that connects the optical head, a shield case 7 that wraps the entire optical head with a magnetic conductive material, and electrically and magnetically shields the outside of the optical head from the inside of the optical head, and an opening formed in the shield case 7. At the same time as taking out the laser light from the shield case 7, an exit window 16 for guiding the reflected light from the recording medium to the lens holder 1, and an objective lens for focusing the laser light emitted inside the lens holder 1 on the recording medium. 15, an output line 14 for taking out the output of the preamplifier to the outside of the optical head, and a slit 19 for taking out the output line from the shield case 7. Although not shown in the figure, a focusing coil and a tracking coil are attached to the side surface of the lens holder 1. By the functions of the magnet 4, the focusing coil, the tracking coil, and the support spring 3, the lens holder 1 is focused so that the laser light is focused on a target position on the recording medium.
The position of is controlled. Further, inside the lens holder 1, an optical semiconductor including a laser chip, a signal detecting means for detecting the reflected light from the optical recording medium, a laser output detecting means for monitoring the amount of laser light emitted from the laser chip, and the like are combined. The element is included.

In the optical semiconductor element, a photodiode is formed on the entire surface of one wafer, and the plurality of signal detecting means are formed by dividing the wafer and drawing out lines. Therefore, the photodiodes also exist in unnecessary areas that are not involved in signal detection, and an abnormal current occurs in these areas. In order to prevent the abnormal current from affecting the signal detection, the anode terminal of the unnecessary photodiode is usually connected to the ground.
In this embodiment, the ground line is led out by a line 10 connecting the preamplifier and the inside of the lens holder 1.

A low-pass filter 9 according to the present invention is attached between the ground line of the line 10 connecting the preamplifier 13 and the inside of the lens holder 1 and the ground terminal of the preamplifier 13. . Here, the cutoff frequency of the low-pass filter 9 is set sufficiently lower than the oscillation frequency of the laser noise reduction means.
The laser noise reduction means 5 is provided on the ground line of the line 10 connecting the preamplifier and the inside of the lens holder 1.
It contains unnecessary high-frequency components leaking from. However, in the present embodiment, most of the high frequency components are removed by the action of the low pass filter 9 and are not input to the power supply terminal of the preamplifier. On the other hand, the power supply to the inside of the lens holder is normally performed as usual. Due to this action, when the laser noise reduction means is driven, the outputs of the preamplifiers of the laser output detection means 26 and the signal detection means 25 drift, and normal laser output control and position control of the optical head are disturbed. It is possible to solve the problem of the conventional optical head. still,
Other operations and configurations are the same as those of the embodiment shown in FIG. 1, and detailed description thereof will be omitted.

FIG. 15 is a circuit diagram showing the structure of the optical head according to this embodiment. In this embodiment, the low pass filter 9 is inserted between the ground line which is the anode terminal of the unnecessary photodiode and the preamplifier 13. Thereby, the laser noise reduction means 5
The high frequency component leaked from the laser output detecting means 26 and the signal detecting means 25 to the preamplifier 13 is not inputted through the ground line. In the present embodiment, it is possible to realize a small-sized and simple-structured optical head that makes use of the characteristics of the optical semiconductor element and that can perform normal laser output control and optical head position control even when the laser noise reduction means 5 is driven. .. Further, even if the laser noise reducing means having a relatively large output is used for the optical head in order to sufficiently obtain the laser noise reducing effect, the drift amount becomes very small, so that the conventional performance is not deteriorated and the drift amount is reduced. It is possible to provide a noise optical head.

(Embodiment 6) FIG. 16 is an explanatory diagram showing the structure of an optical head according to an embodiment of the present invention. In the embodiment of FIG. 10, the circuit of the low-pass filter 9 is formed on the substrate 8. However, the low-pass filter 9
May be any low-pass means having a cutoff frequency sufficiently higher than the control band or signal band of the laser output and sufficiently lower than the oscillation frequency of the laser noise reduction means. For example, as shown in FIG. 16, each wire input to the preamplifier 13 may be passed through a ferrite block 33 to convert unnecessary high frequency components into heat and remove the heat. According to this method, similarly to the embodiment of FIG. 10, it is possible to realize a compact optical head capable of performing normal laser output control and optical head position control even when the laser noise reduction means is driven. Further, as compared with the embodiment of FIG. 10, a much simpler and lower cost filter can be formed, so that the number of manufacturing steps of the optical head can be reduced and the cost can be reduced.
Since the other operations and configurations are the same as those of the embodiment of FIG. 10, detailed description will be omitted.

(Embodiment 7) FIG. 17 is an explanatory view showing the structure of an optical head according to another embodiment of the present invention. Figure 1
In the No. 0 embodiment, the circuit of the low-pass filter 9 is formed on the substrate 8 by using the coil 41, the capacitor 42, and the like. However, the low-pass filter 9
May be any low-pass means having a cutoff frequency sufficiently higher than the control band or signal band of the laser output and sufficiently lower than the oscillation frequency of the laser noise reduction means. For example, as shown in FIG. 16, a magnetic substance may be applied to each line input to the preamplifier 13 through an insulating film, and unnecessary high frequency components may be converted into heat and removed. The magnetic material may be applied on the line 10 connecting the preamplifier and the inside of the lens holder 1 or on the printed pattern of the substrate 8. Figure 1
6 shows a case where the magnetic material is applied onto the printed pattern of the substrate 8. According to this method, similarly to the embodiment of FIG. 10, it is possible to realize a compact optical head capable of performing normal laser output control and optical head position control even when the laser noise reduction means is driven. Furthermore, since the magnetic substance can be easily applied by dipping or printing, the low-pass filter 9 can be formed with a small number of steps. Therefore, it is also possible to realize a small-sized and low-cost optical head. Since the other operations and configurations are the same as those of the embodiment of FIG. 10, detailed description will be omitted.

(Embodiment 8) FIG. 18 is an explanatory view showing the structure of an optical head according to another embodiment of the present invention. Figure 1
In the No. 0 embodiment, the circuit of the low-pass filter 9 is formed on the substrate 8 by using the coil 41, the capacitor 42, and the like. However, the low-pass filter 9
May be any low-pass means having a cutoff frequency sufficiently higher than the control band or signal band of the laser output and sufficiently lower than the oscillation frequency of the laser noise reduction means. For example, as shown in FIG.
Each of the above wiring patterns connected to the input terminal of the preamplifier 13 may have a shape having a high inductance to remove unnecessary high frequency components. According to this method, it is possible to form the low-pass filter 9 by a simple method without increasing the number of steps, and as in the embodiment of FIG. 10, a normal laser output is obtained even when the laser noise reduction means is driven. It is possible to realize a small-sized and low-cost optical head capable of controlling and controlling the position of the optical head. Since the other operations and configurations are the same as those of the embodiment of FIG. 10, detailed description will be omitted.

(Embodiment 9) FIG. 19 is an explanatory view showing the structure of an optical semiconductor element in an embodiment of the present invention. Figure 1
In the embodiment, the low-pass filter 9 is mounted on the input part of the preamplifier 13, but the low-pass filter 9 may be mounted on the output part of the signal detecting means of the optical semiconductor element.

The optical semiconductor element is a laser chip 23,
The reflecting surface 24, the signal detecting means for reproducing the recording information and the position error signal from the reflected light from the recording medium, and the laser output detecting means 26 for detecting the amount of light emitted from the laser chip 23 are integrated on the same substrate. Configured wafer 27,
Polarizing plate 28, laser chip 23 and wafer 27
Is connected to an external circuit by a lead terminal 29.
The laser light emitted from the laser chip 23 in a direction parallel to the surface of the wafer 27 is changed in its traveling direction by 90 ° by the reflection surface 24 and is emitted in the normal direction of the wafer 27. On the other hand, the reflected light from the recording medium is condensed on the signal detecting means 25 inside the optical semiconductor element 22, and the light energy is converted into a current. A focus error signal, a track error signal, and a recording information signal can be generated by electrically calculating the output of the signal detection means.

Although not shown in the figure, the optical semiconductor element 22 is sealed with a transparent sealing member in the emitting direction. The laser light emitted from the laser chip 23 must pass through the transparent sealing member before reaching the diffracting means 21. At this time, a part of the laser light is reflected on the wafer 27, and the laser output detecting means 2
6 is incident. Since the amount of light incident on the laser output detector is proportional to the amount of light emitted from the laser chip 23, the amount of light emitted from the laser chip 23 can be monitored from the output of the laser output detector 26.

In the embodiment of FIG. 19, the low-pass filter 9 according to the present invention is mounted inside the optical semiconductor element and integrated with the optical semiconductor element. In the figure,
The low-pass filter 9 uses a small coil component. Here, the cutoff frequency of the low-pass filter 9 is set sufficiently higher than the signal band of the signal detection means and sufficiently lower than the oscillation frequency of the laser noise reduction means. The output of the signal detecting means includes an unnecessary high frequency component generated from the laser noise reducing means 5. However, in the present embodiment, most of the high frequency components are removed by the action of the low pass filter 9 and are not input to the preamplifier. In particular, in this embodiment, since the high frequency noise has already been removed at the output terminal of the optical semiconductor element, there is no concern that secondary noise radiation will occur on the wiring beyond it. If the optical semiconductor device of this embodiment is mass-produced as a hybrid IC, the circuit configuration of the preamplifier 13 can be simplified and the number of parts can be reduced. On the other hand, the original output of the signal detecting means can pass through the low-pass filter 9 without loss and reach the preamplifier 13, so that the performance of the conventional optical head not equipped with the low-pass filter 9 is improved. There is no loss.

If the optical semiconductor element of this embodiment is used for an optical head, the output of the preamplifier of the signal detecting means will drift when the laser noise reducing means is turned on, and the correct control of the optical head will be hindered. Problems with the conventional optical head can be improved.

Further, since the high frequency leaked from the laser noise reduction means 5 is reduced before the output terminal of the optical semiconductor element, it is not necessary to take any countermeasures on the side of the preamplifier 13, and the optical head can be further downsized and simplified. Be converted. On the other hand, radiation of high-frequency noise from the wiring connecting the optical semiconductor element and the preamplifier 13 is also prevented, and an optical head with less unnecessary radiation of electromagnetic waves can be realized.

(Embodiment 10) FIG. 20 is an explanatory view showing the structure of an optical semiconductor device according to an embodiment of the present invention. In the embodiment of FIG. 19, the low-pass filter is mounted on the output section of the signal detecting means of the optical semiconductor element, but it may be mounted on the output of the laser output detecting means.

In the embodiment of FIG. 20, the low-pass filter 9 according to the present invention is mounted inside the optical semiconductor element and integrated with the optical semiconductor element. In the figure,
The low-pass filter 9 uses a small coil component. Here, the cutoff frequency of the low-pass filter 9 is set sufficiently higher than the control band of the laser output and sufficiently lower than the oscillation frequency of the laser noise reduction means. The output of the laser output detecting means 26 contains an unnecessary high frequency component generated from the laser noise reducing means 5. However, in the present embodiment, most of the high frequency components are removed by the action of the low pass filter 9 and are not input to the preamplifier. In particular,
In this embodiment, since the high frequency noise has already been removed at the output terminal of the optical semiconductor element, there is no concern that secondary noise radiation will occur on the wiring beyond that. Further, if the optical semiconductor device of this embodiment is mass-produced as a hybrid IC,
The circuit configuration of the preamplifier 13 can be simplified and the number of parts can be reduced. On the other hand, the original output of the signal detecting means can pass through the low-pass filter 9 without loss and reach the preamplifier 13, so that the performance of the conventional optical head not equipped with the low-pass filter 9 is improved. There is no loss.

If the optical semiconductor element of this embodiment is used for an optical head, the output of the preamplifier of the laser output detecting means 26 will drift when the laser noise reducing means is turned on.
The problem in the conventional optical head that the correct control of the laser output is disturbed can be improved. Further, since the high frequency leaked from the laser noise reduction means 5 is reduced before the output terminal of the optical semiconductor element, the preamplifier 13
It is not necessary to take any countermeasures on the side, and the optical head can be further downsized and simplified. On the other hand, the optical semiconductor device and the preamplifier 13
Radiation of high frequency noise from the wiring that connects the
It becomes possible to realize an optical head with less unnecessary radiation of electromagnetic waves.
Since the other operations and configurations are the same as those of the embodiment of FIG. 19, detailed description will be omitted.

(Embodiment 11) FIG. 21 is an explanatory view showing the structure of an optical semiconductor device according to an embodiment of the present invention. In the embodiments of FIGS. 19 and 20, the low-pass filter is mounted on the output parts of the signal detecting means and the laser output detecting means of the optical semiconductor element, but a power supply for applying a bias to each of the detecting means on the optical semiconductor element. It may be mounted on the input terminal.

In the embodiment of FIG. 21, the low-pass filter 9 according to the present invention is mounted inside the optical semiconductor element and integrated with the optical semiconductor element. In the figure,
The low-pass filter 9 uses a small coil component. Here, the cutoff frequency of the low-pass filter 9 is set sufficiently higher than the band of the signal detecting means and the control band of the laser output and sufficiently lower than the oscillation frequency of the laser noise reducing means. The input of the power supply terminal contains an unnecessary high frequency component generated from the laser noise reduction means 5. This may leak to the output of each detection means. However, in this embodiment,
Most of the high frequency components are removed by the function of the low pass filter 9 and are not input to the optical semiconductor element. If the optical semiconductor element of this embodiment is mass-produced as a hybrid IC, the circuit configuration of the preamplifier 13 can be simplified and the number of parts can be reduced. On the other hand, the bias voltage can pass through the low-pass filter 9 without loss and reach the respective detection means, so that the performance of the conventional optical head not equipped with the low-pass filter 9 is not impaired.

If the optical semiconductor element of this embodiment is used for an optical head, the output of the preamplifier of the laser output detecting means 26 will drift when the laser noise reducing means is turned on.
The problem in the conventional optical head that the correct control of the laser output is disturbed can be improved. Further, since the high frequency leaked from the laser noise reduction means 5 is reduced at the input terminal of the optical semiconductor element, it is not necessary to take any countermeasures on the side of the preamplifier 13, and the optical head can be further downsized and simplified. Since the other operations and configurations are the same as those of the embodiment of FIG. 19, detailed description will be omitted.

(Embodiment 12) FIG. 22 is an explanatory view showing the structure of an optical semiconductor device according to an embodiment of the present invention. In the embodiments of FIGS. 19 and 20, the low-pass filter is mounted on the output parts of the signal detecting means and the laser output detecting means of the optical semiconductor element, but it may be mounted on the ground terminal on the optical semiconductor element.

The optical semiconductor element as shown in FIG. 21 is usually provided with a ground terminal for connecting the anode terminal of an unnecessary photodiode formed around each detecting means on the wafer 27 to the ground. . When the high frequency noise generated by the laser noise reduction means 5 leaks to this terminal, a problem such as drift occurs in the preamplifier. In the embodiment of FIG. 21, the low-pass filter 9 according to the present invention is attached to the ground line inside the optical semiconductor element and integrated with the optical semiconductor element.
In the figure, the low-pass filter 9 uses a small coil component. Here, the cutoff frequency of the low-pass filter 9 is set sufficiently higher than the band of the signal detecting means and the control band of the laser output and sufficiently lower than the oscillation frequency of the laser noise reducing means. The input to the ground terminal contains an unnecessary high frequency component generated from the laser noise reduction means 5. This may leak to the output of each detection means. However, in the present embodiment, most of the high frequency components are removed by the action of the low pass filter 9 and are not input to the optical semiconductor element. If the optical semiconductor element of this embodiment is mass-produced as a hybrid IC, the circuit configuration of the preamplifier can be simplified and the number of parts can be reduced.
On the other hand, the bias voltage can pass through the low-pass filter 9 without loss and reach the respective detection means, so that the performance of the conventional optical head not equipped with the low-pass filter 9 is not impaired.

If the optical semiconductor device of this embodiment is used for an optical head, the output of the preamplifier of the laser output detecting means 26 will drift when the laser noise reducing means is turned on.
The problem in the conventional optical head that the correct control of the laser output is disturbed can be improved. Further, since the high frequency leaked from the laser noise reduction means 5 is reduced at the input terminal of the optical semiconductor element, it is not necessary to take any countermeasures on the side of the preamplifier 13, and the optical head can be further downsized and simplified. Since the other operations and configurations are the same as those of the embodiment of FIG. 19, detailed description will be omitted.

(Embodiment 13) FIG. 23 is an explanatory view showing the structure of an optical semiconductor device according to an embodiment of the present invention. In the embodiment of FIGS. 19 and 20, a small coil component is mounted as a low pass filter. However, the low-pass filter 9 may be any low-pass means having a cutoff frequency sufficiently higher than the control band or signal band of the laser output and sufficiently lower than the oscillation frequency of the laser noise reduction means. good. For example, as shown in FIG. 23, the output line of each detecting means may be covered with a ferrite block. According to this embodiment, the low pass filter 9 can be easily formed. In addition, it is possible to manufacture a low-cost optical semiconductor device as compared with the embodiment shown in FIG.
Since the other operations and configurations are the same as those of the embodiment of FIG. 19, detailed description will be omitted.

(Embodiment 14) FIG. 24 is an explanatory view showing the structure of an optical semiconductor device according to an embodiment of the present invention. The low-pass filter 9 may be any low-pass means having a cutoff frequency sufficiently higher than the control band or signal band of the laser output and sufficiently lower than the oscillation frequency of the laser noise reduction means. For example, a magnetic material may be applied to the output line of each detection means of the optical semiconductor element via an insulating film, and unnecessary high frequency components may be converted into heat and removed. According to this embodiment, the low pass filter 9 can be easily formed. In addition, it is possible to manufacture a low-cost optical semiconductor device as compared with the embodiment shown in FIG.

According to this method, the same effect as that of the embodiment of FIG. 19 can be obtained, and since the magnetic material can be easily applied by dipping or printing, the low-pass filter 9 can be formed with a small number of steps. Can be formed.
Therefore, it is also possible to realize a small-sized and low-cost optical head. Incidentally, regarding other operations and configurations, FIG.
The detailed description will be omitted because it is the same as that of the first embodiment.

(Embodiment 15) FIG. 25 is an explanatory view showing the structure of an optical semiconductor device according to an embodiment of the present invention. The low-pass filter 9 may be any low-pass means having a cutoff frequency sufficiently higher than the control band or signal band of the laser output and sufficiently lower than the oscillation frequency of the laser noise reduction means. For example, as shown in FIG. 25, each wiring pattern on the wafer 27 connected to the input terminal of each of the detecting means may be formed to have a high inductance to remove unnecessary high frequency components. According to this method, the low-pass filter 9 can be formed by a simple method without increasing the number of steps.
Similar to the embodiment of FIG. 19, a compact and low-cost optical head can be realized. The other operations and configurations are shown in FIG.
Since it is the same as the ninth embodiment, detailed description is omitted.

(Embodiment 16) In the optical disk device, the laser light emitted from the laser diode is reflected by the optical system inside the optical disk and the optical head, and enters the laser diode again to cause noise in each signal output. Is a problem. When an optical disk device is constructed by using the optical head of the present invention, the generation of the noise is prevented by the function of the laser noise reducing means, and the high frequency noise from the laser noise reducing means is applied to the signal detection system by the function of the low pass filter. Since it does not leak, the focusing servo and tracking servo are stable, and the quality of the read signal is also improved. As a result, reading errors are reduced,
It is possible to supply an optical disc device having a higher degree of perfection. Further, in the optical head of the present invention, the high frequency noise input to the preamplifier is reduced, so that the noise emission from the connection line connecting the optical head and the optical disk device is small. Therefore, by using the optical head of the present invention, it becomes possible to provide an optical disc device with less unnecessary radiation noise.

[0109]

As described above, according to the present invention, the following effects are brought about.

(1) In the present invention, the band limiting means according to the present invention is attached between the preamplifier and the signal detecting means. Further, the cutoff frequency of the band limiting means is set sufficiently higher than the signal band of the signal detecting means and sufficiently lower than the oscillation frequency of the laser noise reducing means, and high frequency noise leaking from the laser noise reducing means is set to the above. By attenuating the preamplifier to the allowable input level or less, the preamplifier does not distort the waveform of the high frequency noise. Therefore, when the laser noise reducing means is driven, the operation of the preamplifier becomes unstable, or the output of the preamplifier of the signal detecting means drifts, which hinders correct position control of the optical head. It is possible to improve the problem that Also,
Even if the laser noise reducing means having a relatively large output is used for the optical head in order to sufficiently obtain the laser noise reducing effect, the drift amount becomes very small, so that the low noise can be obtained without impairing the conventional performance. An optical head can be provided.

(2) Further, in the optical head of the present invention, the band limiting means is provided between the preamplifier and the laser output detecting means. Further, the cut-off frequency of the band limiting means is set sufficiently higher than the signal band of the laser output detecting means and sufficiently lower than the oscillation frequency of the laser noise reducing means to prevent high frequency noise leaking from the laser noise reducing means. By attenuating the preamplifier to the allowable input level or less, the waveform of the high frequency noise is not distorted in the preamplifier. As a result, when the laser noise reduction means is driven, the operation of the preamplifier becomes unstable, or the output of the preamplifier of the laser output detection means drifts, which hinders correct control of the laser output. It is possible to improve the problem of the conventional optical head. Further, even if the laser noise reducing means having a relatively large output is used for the optical head in order to sufficiently obtain the laser noise reducing effect, the drift amount becomes very small, so that the conventional performance is not deteriorated and the drift amount is reduced. It is possible to provide a noise optical head.

(3) Further, in the optical head of the present invention, the band limiting means is provided between the common terminal of each detecting means and the power supply terminal of the preamplifier. Further, the cutoff frequency of the band limiting means is set sufficiently higher than the signal band of each of the detecting means and sufficiently lower than the oscillation frequency of the laser noise reducing means, and the high frequency noise leaking from the laser noise reducing means is set to the above. By attenuating the preamplifier to the allowable input level or less, the preamplifier does not distort the waveform of the high frequency noise. Therefore, when the laser noise reduction means is driven, the operation of the preamplifier becomes unstable, the output of the preamplifier of the signal detection means drifts, and the correct position control of the optical head is disturbed. It is possible to solve the problem in the conventional optical head that the output of the preamplifier of the laser output detecting means drifts and the correct control of the laser output is hindered. Further, even if the laser noise reducing means having a relatively large output is used for the optical head in order to sufficiently obtain the laser noise reducing effect, the drift amount becomes very small, so that the conventional performance is not deteriorated and the drift amount is reduced. It is possible to provide a noise optical head.

(4) Further, in the optical head of the present invention, band limiting means is provided between the ground terminal of each of the detecting means and the ground terminal of the preamplifier. Further, the cutoff frequency of the band limiting means is set sufficiently higher than the signal band of each of the detecting means and sufficiently lower than the oscillation frequency of the laser noise reducing means, and the high frequency noise leaking from the laser noise reducing means is set to the above. By attenuating the preamplifier to the allowable input level or less, the preamplifier does not distort the waveform of the high frequency noise. Therefore, when the laser noise reduction means is driven, the operation of the preamplifier becomes unstable, the output of the preamplifier of the signal detection means drifts, and the correct position control of the optical head is disturbed. It is possible to solve the problem in the conventional optical head that the output of the preamplifier of the laser output detecting means drifts and the correct control of the laser output is disturbed. Further, even if the laser noise reducing means having a relatively large output is used for the optical head in order to sufficiently obtain the laser noise reducing effect, the drift amount becomes very small, so that the conventional performance is not deteriorated and the drift amount is reduced. It is possible to provide a noise optical head.

(5) Of the input terminals of the preamplifier,
Band limiting means is provided at terminals other than the terminals connected to the detecting means, and when the high frequency noise leaking from the laser noise reducing means is reduced to the allowable input level of the preamplifier or less, the band limiting means is inserted. The output related to the input terminal can also avoid the influence of the high frequency leaked from the laser noise reduction means. For example, when the temperature detecting means is installed in the optical head and the preamplifier is used for amplification and output, if the band limiting means is inserted between the temperature detecting means and the preamplifier, The temperature detection signal will not drift when the noise reduction means is driven, and erroneous detection will not occur. When the lens holder position detecting means is installed in the optical head and the preamplifier is used for amplification and output, the band limiting means is inserted between the lens holder position detecting means and the preamplifier. If
There is no chance that the lens holder position detection signal will drift when the laser noise reduction means is driven, resulting in erroneous detection.

(6) When the band limiting means is realized by using commonly available coil parts, a low-pass filter can be easily formed, and unnecessary high frequency noise can be removed without a large increase in cost. That is, it is possible to realize a small optical head capable of performing normal laser output control and optical head position control even when the laser noise reduction means is driven.

(7) When a simple band limiting means is formed by passing each wire input to the preamplifier through a magnetic block, similarly, unnecessary high frequency noise can be removed and laser noise can be reduced. Even when the means is driven, it is possible to realize a compact optical head capable of performing normal laser output control and optical head position control. Furthermore, since a much simpler and lower cost band limiting means can be formed, it is possible to reduce the number of manufacturing steps of the optical head and reduce the cost.

(8) When band limiting means is formed by coating a magnetic material on each line input to the preamplifier through an insulating film, unnecessary high frequency components are converted into heat with a simple structure. Therefore, it is possible to realize a small optical head capable of performing normal laser output control and optical head position control even when the laser noise reduction means is driven. Further, since the band limiting means can be formed with a small number of steps, it is possible to realize an even smaller and low cost optical head.

(9) When each inductor input to the preamplifier is formed into a shape or a wiring pattern having a high impedance to simply form an inductor and serve as a band limiting means, a simple structure is obtained. Since unnecessary high frequency components can be removed by the above, a small optical head capable of performing normal laser output control and optical head position control even when the laser noise reduction means is driven can be realized. Further, in this case, since the band limiting means can be formed at the same time as the substrate design of the preamplifier without increasing the number of steps, it is possible to realize a smaller and low cost optical head.

(10) By mounting a low-pass filter on the output section of the signal detecting means of the optical semiconductor element and removing unnecessary high frequency components generated from the laser noise reducing means 5 included in the output of the signal detecting means, Again, it is possible to solve the problem such as drift due to noise in the preamplifier, and prevent secondary noise radiation on the wiring of the signal detecting means and the preamplifier.
Further, if the optical semiconductor device of this embodiment is mass-produced as a hybrid IC, it is not necessary to have the low-pass filter on the side of the preamplifier, so the circuit configuration of the preamplifier 13 is simplified and the number of parts is reduced. can do.

(11) Similarly, a low-pass filter is mounted on the output section of the laser output detecting means of the optical semiconductor element to eliminate unnecessary high frequency components generated from the laser noise reducing means 5 included in the output of the laser output detecting means. By removing it, it is possible to solve the problem such as drift due to noise in the preamplifier, and prevent secondary noise radiation on the wiring of the laser output detecting means and the preamplifier. You can Further, if the optical semiconductor device of this embodiment is mass-produced as a hybrid IC, it is not necessary to have the low-pass filter on the side of the preamplifier, so the circuit configuration of the preamplifier 13 is simplified and the number of parts is reduced. can do.

(12) Similarly, a low-pass filter is inserted in the ground terminal of the optical semiconductor element, and unnecessary high-frequency components generated from the laser noise reduction means 5 included in the output of each detection means pass through the ground line and the preamplifier. By preventing the entry, it is possible to solve the problem such as drift due to noise in the preamplifier, and also to prevent the secondary radiation of noise on the wiring of the laser output detecting means and the preamplifier. Can be prevented. Also,
If the optical semiconductor device of this embodiment is mass-produced as a hybrid IC, it is not necessary to have the low-pass filter on the side of the preamplifier, so that the circuit configuration of the preamplifier 13 can be simplified and the number of parts can be reduced. You can

(13) Similarly, a low-pass filter is inserted in the bias power supply terminal of the optical semiconductor element, and unnecessary high frequency components generated from the laser noise reduction means 5 included in the output of each detection means are pre-passed through the power supply line. By preventing the noise from entering the amplifier, it is possible to solve the problem such as drift due to noise in the preamplifier, and at the same time, secondary radiation of noise on the wiring between the laser output detecting means and the preamplifier. Can be prevented. Also,
If the optical semiconductor device of this embodiment is mass-produced as a hybrid IC, it is not necessary to have the low-pass filter on the side of the preamplifier, so that the circuit configuration of the preamplifier 13 can be simplified and the number of parts can be reduced. You can

(14) The low-pass filter mounted on the output section of the optical semiconductor element may be realized by covering the output line of each detection means with a ferrite block, in which case mass productivity is better than using a small coil component. It is possible to fabricate a low-cost optical semiconductor device which is excellent in high frequency noise removal effect.

(15) The low-pass filter mounted on the output section of the optical semiconductor element may be realized by applying a magnetic material to the output line of each detecting means. In that case, a small coil component or a ferrite block may be used. The structure is further simplified and the weight is reduced as compared with the case of using. Further, since it is excellent in mass productivity, it is possible to manufacture a low-cost optical semiconductor element while having the same high frequency noise removing effect.

(16) The low-pass filter mounted on the output section of the optical semiconductor element may be realized by forming an equivalent inductor by giving a specific routing shape to the output line of each detecting means, In this case, since the low-pass filter can be manufactured in the wafer manufacturing process without increasing the number of processes, the structure is further simplified and the weight is reduced. Further, since it is excellent in mass productivity, it is possible to manufacture a low-cost optical semiconductor element while having the same high frequency noise removing effect.

(17) When an optical head is constructed by using an optical semiconductor element in which a laser chip and the signal detecting means or the laser output detecting means are combined, a compact and simple optical head can be realized. Is the biggest advantage.
However, on the other hand, in the optical semiconductor element, high-frequency noise easily leaks from the laser noise reduction means to the detection means. By using the configuration of the present invention, it is possible to manufacture an optical head that is small in size, simple, and low in cost, making the most of the characteristics of the optical semiconductor element.

(18) In particular, an optical semiconductor element in which a laser chip and the signal detecting means or the laser output detecting means are combined is used, and the preamplifier and the laser noise reducing means are arranged in close proximity to each other to form a small optical head. In that case, high frequency noise is more likely to leak. By using the configuration of the present invention, since the leakage of high frequency noise from the laser noise reduction means to each of the detection means is prevented,
It becomes possible to make an ultra-small optical head.

(19) When an optical information recording / reproducing apparatus is constructed by using the optical head according to the present invention, a laser noise reducing means having a large oscillation output can be mounted, so that the laser noise reducing effect can be fully utilized and low Noise signal detection is possible, stable optical head control, and high-quality information reading become possible. As a result, it is possible to realize a high-performance optical information recording / reproducing apparatus which is stable in operation and has a low error probability.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing the structure of an embodiment of an optical head of the present invention.

FIG. 2 is an explanatory diagram showing the structure of a lens holder in the optical head of FIG.

FIG. 3 is an explanatory diagram showing details of an optical semiconductor element in the optical head of FIG.

FIG. 4 is a block diagram showing an electrical circuit of the optical head of FIG.

5 is an explanatory diagram showing an electric circuit of the optical head of FIG. 1. FIG.

FIG. 6 is an explanatory diagram showing characteristics and actions of a band limiting unit in the optical head of the present invention.

7 is an explanatory view showing another embodiment of the band limiting means in the optical head of FIG.

FIG. 8 is an explanatory view showing the structure of another embodiment of the optical head of the present invention.

9 is a block diagram showing an electric circuit of the optical head of FIG.

FIG. 10 is an explanatory view showing the structure of another embodiment of the optical head of the present invention.

11 is a block diagram showing an electric circuit of the optical head shown in FIG.

FIG. 12 is an explanatory view showing the structure of another embodiment of the optical head of the present invention.

FIG. 13 is an explanatory diagram showing an electrical circuit of the optical head of FIG. 12;

FIG. 14 is an explanatory view showing the structure of another embodiment of the optical head of the present invention.

FIG. 15 is an explanatory diagram showing an electrical circuit of the optical head of FIG.

FIG. 16 is an explanatory view showing the structure of another embodiment of the optical head of the present invention.

FIG. 17 is an explanatory view showing the structure of another embodiment of the optical head of the present invention.

FIG. 18 is an explanatory view showing the structure of another embodiment of the optical head of the present invention.

FIG. 19 is an explanatory view showing the structure of another embodiment of the optical semiconductor element of the present invention.

FIG. 20 is an explanatory view showing the structure of another embodiment of the optical semiconductor element of the present invention.

FIG. 21 is an explanatory view showing the structure of another embodiment of the optical semiconductor element of the present invention.

FIG. 22 is an explanatory view showing the structure of another embodiment of the optical semiconductor element of the present invention.

FIG. 23 is an explanatory view showing the structure of another embodiment of the optical semiconductor element of the present invention.

FIG. 24 is an explanatory view showing the structure of another embodiment of the optical semiconductor element of the present invention.

FIG. 25 is an explanatory view showing the structure of another embodiment of the optical semiconductor element of the present invention.

FIG. 26 is an explanatory diagram showing an example of a structure of a conventional optical head.

FIG. 27 is an explanatory diagram showing an example of a structure of a conventional optical head.

FIG. 28 is an explanatory view showing the structure of a lens holder in the head shown in FIG. 27.

FIG. 29 is an explanatory view showing details of an optical semiconductor element in the head shown in FIG. 27.

FIG. 30 is a block diagram showing an electrical circuit of a conventional optical head.

FIG. 31 is an explanatory diagram for explaining a problem of the conventional optical head.

FIG. 32 is an explanatory diagram for explaining a problem of the conventional optical head.

[Explanation of symbols]

1 Lens Holder 2 Support 3 Support Spring 4 Magnet 5 Laser Noise Reducing Means 6 Penetrating Capacitor 7 Shield Case 8 Substrate 9 Band Limiting Means (Low Pass Filter) 10 Line Connecting the Preamplifier to the Inside of the Lens Holder 11 Laser Noise Reduction A line connecting the means and the inside of the lens holder 12 A line connecting the laser noise reducing means and the feedthrough capacitor 13 Preamplifier 14 Output line 15 Objective lens 16 Outgoing window 17 Focusing coil 18 Tracking coil 19 Slit 20 Flipping mirror 21 Diffraction Means 22 Optical semiconductor element 23 Laser chip 24 Reflecting surface 25 Signal detecting means 26 Laser output detecting means 27 Wafer 28 Polarizing plate 29 Lead terminal 30 Laser diode drive current 31 Signal output 32 Laser output detecting signal 33 Ferrai Block 34 Stray capacitance C1 35 Stray capacitance C2 36 Preamplifier output 37 Photodiode common terminal 38 Photodiode 39 Laser noise reduction means power supply terminal 40 Preamplifier power supply terminal 41 Coil 42 Capacitor 43 High frequency oscillator 44 Laser noise reduction means output 45 Cutoff Frequency fc 46 Laser noise reduction means Frequency f0 47 Linear element 48 Non-linear element 49 DC component input 50 AC component input 51 Laser chip ground 52 Preamplifier ground 53 Dummy photodiode 54 Ferrite paste 55 Prism 56 Collimating lens 57 Semiconductor laser diode

Claims (31)

[Claims] 1. A laser chip, signal detection means for detecting reflected light from an optical recording medium, laser output detection means for monitoring the amount of laser light emitted from the laser chip, or both; the signal detection means or the above. A preamplifier that amplifies the output of the laser output detection means or both,
In a light source unit comprising laser noise reducing means for reducing laser noise by superimposing a high frequency on a laser diode drive current to reduce coherence of laser light, a band is provided between at least one of the detecting means and a preamplifier. An optical head characterized in that a limiting means is inserted, and an upper limit cutoff frequency of a pass band of the band limiting means is set sufficiently lower than an oscillation frequency of the laser noise reducing means. 2. Band limiting means is inserted between the signal detecting means and the preamplifier, and the upper limit cutoff frequency of the pass band of the band limiting means is sufficiently higher than the signal band, and The optical head according to claim 1, wherein the oscillation frequency is set to be sufficiently lower than the oscillation frequency of the laser noise reduction means. 3. The optical head according to claim 2, wherein the band limiting means has a characteristic of reducing the high frequency leaked from the laser noise reducing means to a level smaller than the allowable input level of the preamplifier. . 4. A band limiting means is inserted between the laser output detecting means and the preamplifier, and a cutoff frequency at an upper limit of a pass band of the band limiting means controls the laser output. 2. The optical head according to claim 1, wherein the optical head is set to be sufficiently higher than the band and sufficiently lower than the oscillation frequency of the laser noise reduction means. 5. The optical head according to claim 4, wherein the band limiting means has a characteristic of reducing the high frequency leaked from the laser noise reducing means to a level smaller than the allowable input level of the preamplifier. . 6. A band limiting means is inserted between a bias power supply supplied to the signal detecting means, the laser output detecting means, or both, and the preamplifier, and a pass band of the band limiting means. 2. The optical head according to claim 1, wherein the upper limit cutoff frequency is set to be sufficiently lower than the oscillation frequency of the laser noise reduction means. 7. The optical head according to claim 6, wherein the band limiting means has a characteristic of reducing the high frequency leaked from the laser noise reducing means to a level smaller than the allowable input level of the preamplifier. . 8. A band limiting means is inserted between a ground terminal of the signal detecting means or the laser output detecting means or both of them and a ground terminal of the preamplifier, and a pass band of the band limiting means. 2. The optical head according to claim 1, wherein the upper limit cutoff frequency is set to be sufficiently lower than the oscillation frequency of the laser noise reduction means. 9. The optical head according to claim 8, wherein the band limiting means has a characteristic of reducing the high frequency leaked from the laser noise reducing means to a level smaller than the allowable input level of the preamplifier. . 10. The optical head according to claim 1, wherein the band limiting means is a coil component inserted between the preamplifier and the signal detecting means or the laser output detecting means. . 11. The band limiting means is a magnetic block installed so as to cover a signal line connecting the preamplifier and the signal detecting means or the laser output detecting means. The optical head according to item 1. 12. The light according to claim 1, wherein the band limiting means is a magnetic material applied to a signal line connecting the preamplifier and the signal detecting means or the laser output detecting means. head. 13. The band limiting means includes a wiring pattern on a substrate for connecting the preamplifier and the signal detecting means or the laser output detecting means to a specific shape so as to have frequency characteristics. The optical head according to claim 1, wherein: 14. A laser chip, a signal detecting means for detecting a reflected light from an optical recording medium, a laser output detecting means for monitoring a light quantity of a laser beam emitted from the laser chip, or both, the signal detecting means or the above. A light source including a preamplifier that amplifies the output of the laser output detection means or both, and a laser noise reduction means that reduces the laser noise by superimposing a high frequency on the laser diode drive current to reduce the coherence of the laser light. In the unit, the laser chip and the signal detection means or the laser output detection means or both are configured on the same substrate, and a band limiting means is provided between at least one of the detection means and the preamplifier. In addition, the cutoff frequency at the upper limit of the pass band of the band limiting means is Have been low enough set than the oscillation frequency of the reduction means, the optical head is characterized by having the property of reducing the high frequency which leaks from the laser noise reduction means to the lower level than the allowable input level of the preamplifier. 15. A laser chip, a signal detecting means for detecting reflected light from an optical recording medium, a laser output detecting means for monitoring a light quantity of laser light emitted from the laser chip, the signal detecting means and the laser output. In the light source unit comprising a preamplifier for amplifying the output of the detection means and a laser noise reduction means for reducing the laser noise by superimposing a high frequency on the laser diode drive current to reduce the coherence of the laser light, A chip, the signal detection means, and the laser output detection means each include an optical semiconductor element formed on the same silicon wafer, and one coil component is inserted between each detection means and the preamplifier. Further, the coil component is configured so that the high frequency leaked from the laser noise reduction means is smaller than the allowable input level of the preamplifier. An optical head, characterized in that it has the property of reducing to the level. 16. A laser chip, a signal detecting means for detecting a reflected light from an optical recording medium, a laser output detecting means for monitoring a light quantity of a laser beam emitted from a laser chip, or both, the signal detecting means or the above. A light source including a preamplifier that amplifies the output of the laser output detection means or both, and a laser noise reduction means that reduces the laser noise by superimposing a high frequency on the laser diode drive current to reduce the coherence of the laser light. In the unit, the laser chip and the signal detection means or the laser output detection means or both are configured on the same substrate, and a band limiting means is inserted between at least one of the detection means and an output terminal. Further, the cutoff frequency at the upper limit of the pass band of the band limiting means is the laser noise. The optical semiconductor element characterized in that it is low enough set than the oscillation frequency of the attenuation means. 17. A band limiting means is inserted between the signal detecting means and the preamplifier, and an upper limit cutoff frequency of a pass band of the band limiting means is sufficiently higher than a signal band, and 17. The optical semiconductor device according to claim 16, wherein the oscillation frequency of the laser noise reduction means is set sufficiently lower. 18. The optical semiconductor according to claim 17, wherein said band limiting means has a characteristic of reducing the high frequency leaked from said laser noise reducing means to a level smaller than the allowable input level of said preamplifier. element. 19. A band limiting means is inserted between the laser output detecting means and the preamplifier, and an upper limit cutoff frequency of a pass band of the band limiting means is:
The optical semiconductor element according to claim 16, wherein the optical semiconductor element is set to be sufficiently higher than a band for controlling the laser output and sufficiently lower than an oscillation frequency of the laser noise reduction means. 20. The optical semiconductor according to claim 19, wherein the band limiting means has a characteristic of reducing the high frequency leaked from the laser noise reducing means to a level lower than the allowable input level of the preamplifier. element. 21. Band limiting means is inserted between a bias power supply supplied to the signal detecting means, the laser output detecting means, or both, and the preamplifier.
17. The optical semiconductor device according to claim 16, wherein the upper limit cutoff frequency of the pass band of the band limiting means is set sufficiently lower than the oscillation frequency of the laser noise reducing means. 22. The optical semiconductor according to claim 21, wherein the band limiting means has a characteristic of reducing the high frequency leaked from the laser noise reducing means to a level lower than the allowable input level of the preamplifier. element. 23. Band limiting means is inserted between the ground terminal of the signal detecting means and / or the laser output detecting means or both and the ground terminal of the preamplifier, and the pass band of the band limiting means is further provided. 17. The optical semiconductor device according to claim 16, wherein the cutoff frequency of the upper limit of is set to be sufficiently lower than the oscillation frequency of the laser noise reduction means. 24. The optical semiconductor according to claim 23, wherein the band limiting means has a characteristic of reducing the high frequency leaked from the laser noise reducing means to a level smaller than the allowable input level of the preamplifier. element. 25. An optical semiconductor according to claim 16, wherein said band limiting means is a coil component inserted between said preamplifier and said signal detecting means or said laser output detecting means. element. 26. The band limiting means is a magnetic block installed so as to cover a signal line connecting the preamplifier and the signal detecting means or the laser output detecting means. Item 17. The optical semiconductor device according to item 16. 27. The light according to claim 16, wherein the band limiting means is a magnetic substance applied to a signal line connecting the preamplifier and the signal detecting means or the laser output detecting means. Semiconductor device. 28. The band limiting means is characterized in that a wiring pattern on a substrate connecting the preamplifier and the signal detecting means or the laser output detecting means is given a specific shape to have frequency characteristics. 17. The method according to claim 16,
The optical semiconductor device described. 29. An optical information recording / reproducing apparatus, wherein the optical head according to claim 1 is used as a light source. 30. An optical information recording / reproducing apparatus, wherein the optical head according to claim 15 is used as a light source. 31. An optical information recording / reproducing apparatus, wherein the optical semiconductor element according to claim 16 is used as a light source.