JP2008034548A - Device and method for inspection of semiconductor laser - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inspection device capable of shortening an inspection time without spoiling reliability, in the inspection of a semiconductor laser which outputs a plurality of laser lights having different wavelength. <P>SOLUTION: The inspection device 10 for semiconductor laser 1 which outputs a plurality of laser lights having different wavelengths is equipped with a power supplying unit 11 which supplies respective driving current between terminals for every wavelengths of laser light to be outputted, to make semiconductor lasers of inspection objects simultaneously output laser light having respective wavelengths; a laser light partitioning unit 12 for partitioning the laser lights of a plurality of wavelengths outputted simultaneously from the semiconductor laser of object of inspection into respective wavelengths; a light strength detecting unit 13 for detecting the strength of light with respect to respective laser lights divided into respective wavelengths; a control unit 14 for controlling the driving current so that the strength of light detected with respect to every wavelengths will maintain an already determined value; and a deciding unit 15 for measuring the driving current, with respect to each wavelengths to decide whether the semiconductor laser of inspection object is an excellent article or a faulty article. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an inspection apparatus and inspection method for a semiconductor laser that outputs a plurality of laser beams having different wavelengths, and more particularly to a technique for shortening an inspection time without impairing reliability.

In recent years, various types of optical discs such as CDs, DVDs, and Blu-ray discs have become popular.
Each of these different types of optical disks uses laser light having different wavelengths during recording and reproduction.
Accordingly, in order to handle these optical disks with a single multi-drive, a semiconductor laser capable of selectively outputting a plurality of laser beams having different wavelengths has been developed.

On the other hand, semiconductor lasers generally select initial defective products by outputting laser light continuously for a predetermined time in sorting inspection.
Here, the screening inspection of the semiconductor laser will be briefly described.
FIG. 14 is a diagram showing an outline of a selection inspection of a semiconductor laser that can selectively output infrared, red, and blue laser beams corresponding to each of three types of optical disks, CD, DVD, and Blu-ray disc. is there.

As shown in FIG. 14, in the selection inspection of the semiconductor laser, first, only the infrared laser for CD is driven, the light intensity is measured by the light receiving element, and the drive current is controlled so that the light intensity is maintained at the predetermined value. Next, only the red laser for DVD is driven, the light intensity is measured by the light receiving element, the drive current is controlled so that the light intensity maintains a predetermined value, and then only the blue laser is driven to receive light. The light intensity is measured by the element, and the drive current is controlled so that the light intensity maintains a predetermined value. As the inspection time elapses, the drive current greatly fluctuated while the light intensity is constant is excluded as a defective product (see Patent Document 1).
JP 2004-179407 A

As described above, the selection inspection of the semiconductor laser takes about 1 to 6 hours even for the inspection of only one type of wavelength, and in the case of a plurality of types of inspection, it simply takes several times as long as the type. The burden on is very large.
Even if a plurality of wavelengths of laser light are simultaneously driven to inspect a plurality of wavelengths at the same time, the output position of each laser light is very close, so the light receiving element is the total light of the laser lights of a plurality of wavelengths. The intensity is measured, and it is not possible to control the light intensity to be kept constant for each wavelength, and it is impossible to measure the drive current with the light intensity constant for each wavelength. It will be damaged.

  Accordingly, an object of the present invention is to provide an inspection apparatus and an inspection method capable of reducing an inspection time without impairing reliability in inspection of a semiconductor laser that outputs a plurality of laser beams having different wavelengths.

  In order to achieve the above object, an inspection apparatus according to the present invention is a semiconductor laser inspection apparatus that outputs a plurality of laser beams having different wavelengths, and a driving current is provided between terminals for each wavelength of the laser light to be output. Supply means for simultaneously outputting laser light of each wavelength to the semiconductor laser to be inspected, and laser light for dividing the laser light of multiple wavelengths simultaneously output from the semiconductor laser to be inspected for each wavelength A splitting unit; a detecting unit for detecting the light intensity of each of the laser beams divided for each wavelength by the laser beam splitting unit; and a power feeding unit for maintaining the predetermined value for the light intensity detected by the detecting unit for each wavelength. Control means for controlling the drive current by the laser, and determination means used for determining whether the semiconductor laser to be inspected is a non-defective product or a defective product by measuring the drive current for each wavelength. Characterized in that it comprises a.

  In order to achieve the above object, an inspection method according to the present invention is a semiconductor laser inspection method for outputting a plurality of laser beams having different wavelengths, and a drive current is applied between terminals for each wavelength of the laser beam to be output. Supplying step to supply laser light of each wavelength to the semiconductor laser to be inspected simultaneously and laser light division to divide the laser light of multiple wavelengths simultaneously output from the semiconductor laser to be inspected for each wavelength A detection step for detecting the light intensity of each of the laser beams divided for each wavelength by the laser beam splitting step, and a power feeding step so that the light intensity detected by the detection step for each wavelength maintains a predetermined value. Control step for controlling the drive current and whether the semiconductor laser to be inspected is good or defective by measuring the drive current for each wavelength Characterized in that it comprises a determination step of using a constant.

  In order to achieve the above object, an inspection method according to the present invention is an inspection method of a semiconductor laser that outputs a plurality of laser beams having different wavelengths, and is provided between terminals for each wavelength of the laser beam to be output in the initial stage of the inspection. By sequentially supplying drive current and outputting each laser beam sequentially to the semiconductor laser to be inspected, and detecting the light intensity of the laser beam output from the semiconductor laser for each wavelength, the detected light intensity is predetermined. The drive current is controlled for each wavelength so that the value is maintained, and the drive current is measured and held for each wavelength, and the drive current is fixed between the terminals for each wavelength of the laser light to be output in the middle of the inspection. A drive current is supplied between the intermediate step for supplying and outputting each laser beam simultaneously to the semiconductor laser to be inspected, and the terminal for each wavelength of the laser beam to be output at the end of the inspection. Each laser beam is sequentially output to the semiconductor laser to be inspected, and the detected light intensity is maintained at a predetermined value while detecting the light intensity of the laser beam output from the semiconductor laser for each wavelength in a time-sharing manner. Comparing the final step, which controls the drive current for each wavelength and measures and holds the drive current for each wavelength, and the drive current value held by the initial step for each wavelength and the drive current value held by the final step And determining the difference between the values of the drive currents to determine whether the semiconductor laser to be inspected is a good product or a defective product.

  With the configuration described in the means for solving the problems, while simultaneously outputting laser light of a plurality of wavelengths, the laser light is divided for each wavelength, the light intensity is detected, and the light intensity is predetermined for each wavelength. Since it can be controlled to maintain the value, the inspection time can be greatly shortened without impairing the reliability of the inspection. For example, a semiconductor laser that outputs laser light of two types of wavelengths reduces the inspection time to about 1/2 of the conventional time, and a semiconductor laser that outputs laser light of three types of wavelengths reduces the time to about 1/3 of the conventional time. can do.

  In addition, with the configuration described in the means for solving the problems, laser light of a plurality of wavelengths is output in a time-sharing manner at the initial stage and the final stage of the inspection, and the drive current is measured for each wavelength. Since it is possible to supply a fixed number of laser beams with multiple power supplies at the same time, it is possible to measure the drive current for each wavelength while overloading the inspection target for most of the inspection time. Inspection time can be greatly shortened without impairing inspection reliability.

  Further, in the inspection apparatus, the laser beam splitting unit is a filter capable of switching a wavelength to be transmitted so that each of a plurality of laser beams having different wavelengths that are output at the same time cannot transmit laser beams of other wavelengths. The wavelength of light transmitted through time division is switched, and the detection means detects the light intensity for each wavelength by time division using a common detection element.

As a result, the wavelength that the filter transmits in time division is switched, so that the light intensity can be detected for each wavelength in time division using one light receiving element.
In the inspection apparatus, the plurality of laser beams having different wavelengths are infrared, red, and blue laser beams, and the filter is a liquid crystal filter that transmits each of the infrared, red, and blue laser beams. It is also possible to switch the wavelength to be switched.

Thereby, the liquid crystal filter can switch the wavelength to be transmitted for each of the infrared, red, and blue laser beams, and the inspection time can be shortened to about 1/3 that of the prior art.
Further, in the inspection apparatus, the laser beam splitting unit includes a diffraction grating that spatially separates each of a plurality of laser beams having different wavelengths output at the same time by a difference in diffraction angle depending on the wavelength, and the detection unit includes the diffraction beam For each of the laser beams spatially separated for each wavelength by the grating, the light intensity can be detected using a dedicated detection element.

As a result, the diffraction grating separates laser beams having spatially different wavelengths, so that the light intensity can be detected using a dedicated detection element for each.
In the inspection apparatus, the plurality of laser beams having different wavelengths are infrared, red, and blue laser beams, and the diffraction grating spatially separates each of the infrared, red, and blue laser beams. It can also be characterized.

As a result, the diffraction grating can spatially separate each of the infrared, red, and blue laser beams, and the inspection time can be shortened to about 1/3 that of the prior art.
The inspection apparatus may further include an optical system that condenses each laser beam that has passed through the diffraction grating and guides the laser beam to a corresponding detection element.
As a result, the distance between the detection elements can be reduced, so the occupied area per inspection object can be reduced and the number of simultaneous inspections per installation place can be increased. In addition, since interference between outgoing lights can be suppressed, inspection can be performed with higher accuracy.

(Embodiment 1)
<Overview>
FIG. 1 is a diagram showing an overview of Embodiment 1 of the present invention.
In the first embodiment of the present invention, an infrared laser beam 2, a red laser beam 3, and a blue laser beam 4 are simultaneously output to a semiconductor laser 1 to be inspected, and a laser beam transmitted through a liquid crystal filter 5 is switched and shared. The detection element 6 detects the light intensity for each wavelength, and controls the drive current so that each light intensity maintains a predetermined value in a time division manner (APC control).

<Configuration>
FIG. 2 is a diagram showing a configuration of the inspection apparatus 10 according to Embodiment 1 of the present invention.
As shown in FIG. 2, the inspection apparatus 10 according to the first embodiment of the present invention includes a power feeding unit 11, a laser beam splitting unit 12, a light intensity detection unit 13, a control unit 14, and a determination unit 15.
The power supply unit 11 supplies a drive current between terminals for each wavelength of laser light to be output, and causes the semiconductor laser 1 to be inspected to simultaneously output laser light of each wavelength. Here, drive currents corresponding to infrared laser light, red laser light, and blue laser light are respectively supplied between corresponding terminals, and the semiconductor laser 1 to be inspected is supplied with infrared laser light, red laser light, and Blue laser light is output simultaneously.

  The laser beam splitting unit 12 splits laser beams of a plurality of wavelengths that are simultaneously output from the semiconductor laser to be inspected for each wavelength. Here, for each of the infrared laser beam, the red laser beam, and the blue laser beam, the filter 5 that can switch the wavelength to be transmitted can be set so that the laser beam having other wavelengths cannot be transmitted. Switch the wavelength to be transmitted by dividing.

The light intensity detection unit 13 detects the light intensity for each wavelength in a time division manner for each of the laser beams divided for each wavelength by the laser beam division unit 12 using the common detection element 6.
The control unit 14 controls the drive current supplied by the power supply unit 11 so that the light intensity detected by the light intensity detection unit 13 maintains a predetermined value for each wavelength, and also to the laser beam splitting unit 12. An instruction to switch the wavelength to be transmitted is periodically issued, and the determination unit 15 is instructed when to measure the drive current.

  The determination unit 15 receives an instruction from the control unit 14 and measures the driving current at the initial stage of inspection and the driving current at the end of the inspection for each wavelength, and the semiconductor laser to be inspected is a good product or a defective product. Used to determine whether or not More specifically, it is determined that the difference between the values of these drive currents does not exceed the threshold value at all wavelengths is a non-defective product, and that the difference between the drive current values even at one wavelength exceeds the threshold value is a defective product.

<Operation>
FIG. 3 is a diagram showing an outline of the selection inspection of the semiconductor laser in the first embodiment of the present invention.
FIG. 4 is a diagram showing the procedure of the semiconductor laser sorting inspection in the first embodiment of the present invention.

The operation of the inspection apparatus 10 will be described below with reference to FIGS.
(1) When the control unit 14 receives an instruction to start the inspection from the outside, the control unit 14 issues an instruction to the power supply unit 11 and corresponds to each of the infrared laser light, the red laser light, and the blue laser light of the semiconductor laser to be inspected. An average driving current is supplied between the terminals to be operated (step S1).
(2) The control unit 14 instructs the laser beam splitting unit 12 to transmit only the infrared laser beam (section A, step S2).

(3) It is determined whether or not the control time for the infrared laser has passed (section A, step S3). Here, for example, it is determined whether approximately 1 minute has elapsed.
(4) The light intensity detector 13 measures the light intensity of the infrared laser light (section A, step S4).
(5) The control unit 14 controls the drive current supplied between the terminals corresponding to the infrared laser light so that the light intensity of the infrared laser light becomes a predetermined value (section A, step S5).

(6) When the control time for the infrared laser beam has elapsed, the control unit 14 instructs the laser beam splitting unit 12 to transmit only the red laser beam (section B, step S6).
(7) It is determined whether or not the control time for the red laser beam has passed (section B, step S7). Here, for example, it is determined whether approximately 1 minute has elapsed.
(8) The light intensity detection unit 13 measures the light intensity of the red laser light (section B, step S8).

(9) The control unit 14 controls the drive current supplied between the terminals corresponding to the red laser light so that the light intensity of the red laser light becomes a predetermined value (section B, step S9).
(10) When the control time for the red laser beam has elapsed, the control unit 14 instructs the laser beam splitting unit 12 to transmit only the blue laser beam (section C, step S10).

(11) It is determined whether or not the control time for the blue laser light has passed (section C, step S11). Here, for example, it is determined whether approximately 1 minute has elapsed.
(12) The light intensity detection unit 13 measures the light intensity of the blue laser light (section C, step S12).
(13) The control unit 14 controls the drive current supplied between the terminals corresponding to the blue laser light so that the light intensity of the blue laser light becomes a predetermined value (section C, step S13).

(14) When the control time for the blue laser light has elapsed, the determination unit 15 determines whether or not each driving current in the initial stage of inspection has already been stored (step S14).
(15) If each drive current is not stored, the determination unit 15 determines whether or not the light intensity of all the laser beams is a predetermined value and each drive current is stabilized (step S15).
(16) When each drive current is stabilized, the determination unit 15 stores each drive current at the initial stage of the inspection (step S16).

(17) When each drive current is stored, the control unit 14 determines whether or not the inspection time of the screening inspection has elapsed. Until the inspection time elapses, the output of each laser beam is continued (step S17). Here, for example, it is determined whether approximately 1 hour has passed, and the output of each laser beam is continued for approximately 1 hour.
(18) When the inspection time has elapsed, the determination unit 15 stores each drive current at the end of the inspection (step S18).

(19) The control unit 14 issues an instruction to the power supply unit 11 to stop the supply of all drive currents (step S19).
(20) The determination unit 15 calculates, for each wavelength, whether the difference between the value of the drive current stored at the initial stage of the inspection and the value of the drive current stored at the end of the inspection exceeds the threshold value. In step S20, a product that does not exceed the threshold value is determined to be a non-defective product, and a product that exceeds the threshold value even at one wavelength is determined to be a defective product, and a determination result is output (step S20).

Here, the liquid crystal filter is used for switching the laser beam to be transmitted, but another filter may be used. For example, a plurality of filters that transmit only the respective laser beams may be mechanically replaced.
FIG. 5 is a diagram illustrating an example of another filter 7.
In the example of FIG. 5, a filter that transmits only infrared laser light, a filter that transmits only red laser light, and a filter that transmits only blue laser light are attached to a large rotating plate almost uniformly. The filter is rotated together with the rotating plate to switch the laser beam to be transmitted.

<Summary>
As described above, according to the first embodiment of the present invention, a plurality of laser beams can be output at the same time, and the laser beams transmitted through the filter can be switched to drive each laser beam with a constant light intensity. Inspection time can be greatly shortened without impairing inspection reliability.
(Embodiment 2)
<Overview>
FIG. 6 is a diagram showing an outline of the second embodiment of the present invention.

  In the second embodiment of the present invention, an infrared laser beam 2, a red laser beam 3, and a blue laser beam 4 are simultaneously output to a semiconductor laser 1 to be inspected, and a traveling angle of each laser beam is changed using a diffraction grating 8. These are semiconductor laser inspection devices that detect light intensity by using dedicated detection elements 9a, 9b, and 9c, respectively, and control drive current so that each light intensity maintains a predetermined value (APC control).

<Configuration>
FIG. 7 is a diagram showing a configuration of the inspection apparatus 20 according to the second embodiment of the present invention.
As shown in FIG. 7, the inspection apparatus 20 according to the second embodiment of the present invention includes a power feeding unit 11, a laser beam splitting unit 21, a light intensity detection unit 22, a control unit 23, and a determination unit 15.
In addition, the same number is attached | subjected to the component similar to Embodiment 1, and the description is abbreviate | omitted.

  The laser beam splitting unit 21 splits laser beams of a plurality of wavelengths that are simultaneously output from the semiconductor laser to be inspected for each wavelength. Here, using the diffraction grating 8 that spatially separates each of the infrared laser beam, red laser beam, and blue laser beam according to the difference in diffraction angle depending on the wavelength, the traveling angle of each laser beam is changed and dedicated to each. To the detection elements 9a, 9b and 9c.

Here, when the grating pitch of the diffraction grating is “d”, the diffraction angle is “θ”, and the wavelength of the laser beam is “λ”, the following relationship is established.

d · sin θ = λ

Therefore, the wavelength of infrared laser light is λ1 = 0.785 μm, the wavelength of red laser light is λ2 = 0.660 μm, the wavelength of blue laser light is λ1 = 0.410 μm, and the grating pitch of the diffraction grating is d = Assuming 3 μm, the diffraction angle of infrared laser light is θ1 = 15.1 °, the diffraction angle of red laser light is θ2 = 12.7 °, and the diffraction angle of blue laser light is θ3 = 7.8 °. .

On the other hand, each laser beam output from the semiconductor laser 1 has an emission angle of about 24 °.
FIG. 8 is a diagram illustrating an example of the positional relationship between the diffraction grating 8 and the detection elements 9a, 9b, and 9c.
As shown in FIG. 8, the distance between the semiconductor laser 1 and the diffraction grating 8 and the distance between the diffraction grating 8 and the detection elements 9a, 9b, and 9c are appropriately set, and each of the laser beams is transmitted using different detection elements. Detect the light intensity.

The light intensity detector 22 detects the light intensity of each of the laser beams divided for each wavelength by the laser beam splitter 21 using dedicated detection elements 9a, 9b, 9c.
The control unit 23 controls the drive current supplied by the power supply unit 11 so that the light intensity detected by the light intensity detection unit 22 maintains a predetermined value for each wavelength, and also supplies the drive current to the determination unit 15. Instruct the timing to measure.

<Operation>
FIG. 9 is a diagram showing the procedure of the semiconductor laser sorting inspection in the second embodiment of the present invention.
The operation of the inspection apparatus 20 will be described below with reference to FIG.
Steps similar to those in FIG. 4 of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

(1) When the control unit 23 receives an instruction to start an inspection from the outside, the control unit 23 issues an instruction to the power supply unit 11 and corresponds to each of the infrared laser beam, the red laser beam, and the blue laser beam of the semiconductor laser to be inspected. An average drive current is supplied between the terminals to be operated (step S21).
(2) The light intensity detection unit 22 measures the light intensity of the infrared laser light by the detection element 9a, measures the light intensity of the red laser light by the detection element 9b, and measures the light intensity of the blue laser light by the detection element 9c. (Step S22).

  (3) The control unit 23 controls the drive current supplied between the terminals corresponding to the infrared laser light so that the light intensity of the infrared laser light becomes a predetermined value, and the light intensity of the red laser light becomes a predetermined value. In this way, the drive current supplied between the terminals corresponding to the red laser light is controlled, and the drive current supplied between the terminals corresponding to the blue laser light is controlled so that the light intensity of the blue laser light becomes a predetermined value. (Step S23).

(4) to (6) Same as (14) to (16) of the first embodiment (steps S14 to S16).
(7) When each drive current is stored, the control unit 23 determines whether or not the inspection time of the screening inspection has elapsed. Until the inspection time elapses, the output of each laser beam is continued (step S24). Here, for example, it is determined whether one hour has passed, and the output of each laser beam is continued for about one hour.

(8) Same as (18) of the first embodiment (step S18).
(9) The control unit 23 issues an instruction to the power supply unit 11 to stop supply of all drive currents (step S25).
(10) Same as (20) of the first embodiment (step S20).
<Summary>
As described above, according to the second embodiment of the present invention, it is possible to simultaneously output a plurality of laser beams, separate and detect the laser beams by the diffraction grating, and drive each laser beam with a constant light intensity. Therefore, the inspection time can be significantly shortened without impairing the reliability of the inspection.
(Embodiment 3)
<Overview>
FIG. 10 is a diagram showing an outline of the third embodiment of the present invention.

In the third embodiment of the present invention, the inspection apparatus of the second embodiment further includes an optical system 31 that condenses each laser beam between the diffraction grating 8 and the detection elements 9a, 9b, and 9c. This is a laser inspection device.
<Configuration>
FIG. 10 is a diagram showing the configuration of the inspection apparatus 30 according to Embodiment 3 of the present invention.

As shown in FIG. 10, the inspection apparatus 30 according to the second embodiment of the present invention includes a power feeding unit 11, a laser beam splitting unit 21, an optical system 31, a light intensity detection unit 32, a control unit 23, and a determination unit 15. .
In addition, the same number is attached | subjected to the component similar to Embodiment 2, and the description is abbreviate | omitted.
The optical system 31 collects each laser beam that has passed through the diffraction grating 8 as a whole and guides it to the corresponding detection element, and is constituted by a convex lens, for example.

  Similarly to the light intensity detection unit 22 of the second embodiment, the light intensity detection unit 32 uses dedicated detection elements 9a, 9b, and 9c for each of the laser beams divided for each wavelength by the laser beam dividing unit 21. The light intensity detection unit 22 is different from the light intensity detection unit 22 in the interval between the detection elements, and the divided laser light is entirely condensed by the optical system 31. Is miniaturized.

<Operation>
The operation of the inspection apparatus 30 is the same as that in the second embodiment.
<Summary>
As described above, according to the third embodiment of the present invention, since the distance between the detection elements can be reduced by the optical system for condensing each laser beam, the occupied area per inspection object can be reduced and installed. The number of simultaneous inspections per place can be increased. In addition, since interference between outgoing lights can be suppressed, inspection can be performed with higher accuracy.
(Embodiment 4)
<Overview>
In the fourth embodiment of the present invention, the drive current is set so that the light intensity is maintained at a predetermined value in order of the infrared laser light, the red laser light, and the blue laser light in order at a relatively short time in the initial stage and the final stage of the inspection. Control (APC control), memorize each driving current, and output infrared laser light, red laser light, and blue laser light for a relatively long time in the middle of the inspection (ACC control) at the same time so that the driving current becomes constant (ACC control) This is a semiconductor laser inspection apparatus that selects an initial defective product by comparing the drive current stored at the beginning of inspection with the drive current stored at the end of inspection for each laser beam.

<Configuration>
FIG. 11 is a diagram showing a configuration of the inspection apparatus 40 according to Embodiment 4 of the present invention.
As shown in FIG. 11, the inspection apparatus 40 according to Embodiment 4 of the present invention includes a power feeding unit 11, a light intensity detection unit 13, a control unit 41, and a determination unit 15.
In addition, the same number is attached | subjected to the component similar to Embodiment 1, and the description is abbreviate | omitted.

  At the initial stage of inspection and at the end of inspection, the control unit 41 sequentially supplies a drive current between terminals for each wavelength of the laser light to be output, and sequentially outputs each laser light to the semiconductor laser to be inspected. Each time, the light intensity detected by the light intensity detection unit 13 controls the drive current supplied by the power supply unit 11 so that the predetermined value is maintained, and in the middle of the inspection, the wavelength of the laser light to be output The driving current supplied by the power supply unit 11 is controlled so that the driving current is supplied in a fixed manner, and the respective laser beams are simultaneously output to the semiconductor laser to be inspected. Instruct the timing to measure the drive current.

<Operation>
FIG. 12 is a diagram showing an outline of the semiconductor laser screening inspection in the fourth embodiment of the present invention.
FIG. 13 is a diagram showing a procedure for screening inspection of a semiconductor laser according to the fourth embodiment of the present invention.

Hereinafter, the operation of the inspection apparatus 40 will be described with reference to FIGS.
Steps similar to those in FIG. 4 of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
(1) When the control unit 41 receives an instruction to start an inspection from the outside, the control unit 41 issues an instruction to the power supply unit 11 to supply an average driving current between terminals corresponding to the infrared laser light of the semiconductor laser to be inspected. (Step S41).

(2) It is determined whether or not the control time for the infrared laser at the initial stage of the inspection has elapsed (section A, step S42). Here, for example, it is determined whether approximately 1 minute has elapsed.
(3) The light intensity detector 13 measures the light intensity of the infrared laser light (section A, step S43).
(4) The control unit 41 controls the drive current supplied between the terminals corresponding to the infrared laser light so that the light intensity of the infrared laser light becomes a predetermined value (section A, step S44).

(5) When the control time for the infrared laser beam at the initial stage of inspection has elapsed, the determination unit 15 stores the drive current of the infrared laser beam at the initial stage of inspection (step S45).
(6) The control unit 41 issues an instruction to the power supply unit 11 to stop the output of the infrared laser beam and supply an average driving current between the terminals corresponding to the red laser beam of the semiconductor laser to be inspected. (Step S47).

(7) It is determined whether or not the control time for the red laser beam at the initial stage of inspection has passed (section B, step S47). Here, for example, it is determined whether approximately 1 minute has elapsed.
(8) The light intensity detection unit 13 measures the light intensity of the red laser light (section B, step S48).
(9) The control unit 41 controls the drive current supplied between the terminals corresponding to the red laser light so that the light intensity of the red laser light becomes a predetermined value (section B, step S49).

(10) When the control time for the red laser light at the initial stage of inspection has elapsed, the determination unit 15 stores the drive current of the red laser light at the initial stage of inspection (step S50).
(11) The control unit 41 gives an instruction to the power supply unit 11 to stop the output of the red laser light and supply an average driving current between the terminals corresponding to the blue laser light of the semiconductor laser to be inspected. (Step S51).

(12) It is determined whether or not the control time for the blue laser light at the initial stage of inspection has elapsed (section C, step S52). Here, for example, it is determined whether approximately 1 minute has elapsed.
(13) The light intensity detection unit 13 measures the light intensity of the blue laser light (section C, step S53).
(14) The control unit 41 controls the drive current supplied between the terminals corresponding to the blue laser light so that the light intensity of the blue laser light becomes a predetermined value (section C, step S54).

(15) When the control time for the blue laser light at the initial stage of inspection has elapsed, the determination unit 15 stores the drive current of the blue laser light at the initial stage of inspection (step S55).
(16) The control unit 41 issues an instruction to the power supply unit 11 and is stored by the determination unit 15 between terminals corresponding to the infrared laser beam, the red laser beam, and the blue laser beam of the semiconductor laser to be inspected. The supplied drive current is supplied in a fixed manner (step S56).

(17) The control unit 41 determines whether the inspection time for the screening inspection has elapsed. Until the inspection time elapses, the output of each laser beam is continued (step S57). Here, for example, it is determined whether 58 minutes have passed, and the output of each laser beam is continued for 58 minutes.
(18) When the inspection time has elapsed, the control unit 41 instructs the power supply unit 11 to stop the output of the red laser beam and the blue laser beam, and only between the terminals corresponding to the infrared laser beam. The supply of drive current is continued (step S58).

(19) It is determined whether or not the control time for the infrared laser at the end of the inspection has elapsed (section A, step S59). Here, for example, it is determined whether approximately 1 minute has elapsed.
(20) The light intensity detector 13 measures the light intensity of the infrared laser light (section E, step S60).
(21) The control unit 41 controls the drive current supplied between the terminals corresponding to the infrared laser light so that the light intensity of the infrared laser light becomes a predetermined value (section E, step S61).

(22) When the control time for the infrared laser light at the end of the inspection has elapsed, the determination unit 15 stores the drive current of the infrared laser light at the end of the inspection (step S62).
(23) The control unit 41 issues an instruction to the power supply unit 11 to stop the output of the infrared laser beam and supply an average driving current between the terminals corresponding to the red laser beam of the semiconductor laser to be inspected. (Step S63).

(24) It is determined whether or not the control time for the red laser beam at the end of the inspection has elapsed (section F, step S64). Here, for example, it is determined whether approximately 1 minute has elapsed.
(25) The light intensity detection unit 13 measures the light intensity of the red laser light (section F, step S65).
(26) The control unit 41 controls the drive current supplied between the terminals corresponding to the red laser light so that the light intensity of the red laser light becomes a predetermined value (section F, step S66).

(27) When the control time for the red laser light at the end of the inspection has elapsed, the determination unit 15 stores the drive current of the red laser light at the end of the inspection (step S67).
(28) The control unit 41 issues an instruction to the power supply unit 11 to stop the output of the red laser beam and supply an average drive current between the terminals corresponding to the blue laser beam of the semiconductor laser to be inspected. (Step S68).

(29) It is determined whether or not the control time for the blue laser light at the end of the inspection has elapsed (section G, step S69). Here, for example, it is determined whether approximately 1 minute has elapsed.
(30) The light intensity detector 13 measures the light intensity of the blue laser light (section G, step S70).
(31) The control unit 41 controls the drive current supplied between the terminals corresponding to the blue laser light so that the light intensity of the blue laser light becomes a predetermined value (section G, step S71).

(32) When the control time for the blue laser light at the end of the inspection has elapsed, the determination unit 15 stores the drive current of the blue laser light at the end of the inspection (step S72).
(33) The control unit 41 issues an instruction to the power supply unit 11 to stop the supply of all drive currents (step S73).
(34) Same as (20) of the first embodiment (step S20).

<Summary>
As described above, according to the fourth embodiment of the present invention, each laser beam is driven so that the light intensity maintains a predetermined value in a time-sharing manner for each wavelength for a relatively short time at the initial stage and the final stage of the inspection. By controlling the current and outputting multiple laser beams at the same time so that the drive current is constant for a relatively long time in the middle of the inspection, the inspection time can be greatly shortened without impairing the reliability of the inspection. .

  The present invention can be applied to an optical disc drive. According to the present invention, the inspection time of a semiconductor laser capable of selectively outputting a plurality of laser beams having different wavelengths used in a multi-drive that handles different types of optical discs is greatly reduced without impairing the reliability of the inspection. Therefore, the productivity of the semiconductor laser can be increased and a significant cost reduction can be expected, so that its industrial utility value is extremely high.

It is a figure which shows the outline | summary of Embodiment 1 of this invention. It is a figure which shows the structure of the test | inspection apparatus 10 in Embodiment 1 of this invention. It is a figure which shows the outline of the selection inspection of the semiconductor laser in Embodiment 1 of this invention. It is a figure which shows the procedure of the selection inspection of the semiconductor laser in Embodiment 1 of this invention. It is a figure which shows an example of the other filter. FIG. 6 is a diagram showing an outline of the second embodiment of the present invention. It is a figure which shows the structure of the test | inspection apparatus 20 in Embodiment 2 of this invention. It is a figure which shows the example of the positional relationship of the diffraction grating 8 and detection element 9a, 9b, 9c. It is a figure which shows the procedure of the selection inspection of the semiconductor laser in Embodiment 2 of this invention. It is a figure which shows the structure of the test | inspection apparatus 30 in Embodiment 3 of this invention. It is a figure which shows the structure of the test | inspection apparatus 40 in Embodiment 4 of this invention. It is a figure which shows the outline of the selection inspection of the semiconductor laser in Embodiment 4 of this invention. It is a figure which shows the procedure of the selection inspection of the semiconductor laser in Embodiment 4 of this invention. It is a figure which shows the outline of the selection test | inspection of the semiconductor laser which can selectively output the infrared-ray, red, and blue laser beam corresponding to each of three types of optical disks, CD, DVD, and a Blu-ray Disc.

Explanation of symbols

DESCRIPTION OF SYMBOLS 5 Liquid crystal filter 6 Detection element 7 Filter 8 Diffraction grating 9a Detection element 9b Detection element 9c Detection element 10 Inspection apparatus 11 Feeding part 12 Laser beam splitting part 13 Light intensity detection part 14 Control part 15 Determination part 20 Inspection apparatus 21 Laser beam splitting part 22 light intensity detection unit 23 control unit 30 inspection device 31 optical system 32 light intensity detection unit 40 inspection device 41 control unit

Claims (8)

A semiconductor laser inspection apparatus for outputting a plurality of laser beams having different wavelengths,
Power supply means for supplying a driving current between terminals for each wavelength of laser light to be output, and simultaneously outputting laser light of each wavelength to a semiconductor laser to be inspected,
A laser beam splitting means for splitting laser beams of a plurality of wavelengths output simultaneously from a semiconductor laser to be inspected for each wavelength;
Detecting means for detecting the light intensity for each of the laser beams divided for each wavelength by the laser beam dividing means;
Control means for controlling the drive current by the power supply means so that the light intensity detected by the detection means maintains a predetermined value for each wavelength;
An inspection apparatus comprising: a determination unit that measures a drive current for each wavelength and determines whether a semiconductor laser to be inspected is a good product or a defective product. The laser beam splitting unit includes a filter capable of switching a wavelength to be transmitted, wherein each of a plurality of laser beams having different wavelengths that are output at the same time can transmit laser beams having other wavelengths. Switch the wavelength to transmit in time division,
The inspection apparatus according to claim 1, wherein the detection unit detects light intensity for each wavelength in a time division manner using a common detection element. The laser beams having different wavelengths are infrared, red, and blue laser beams,
The inspection apparatus according to claim 2, wherein the filter is a liquid crystal filter, and switches a wavelength to be transmitted for each of infrared, red, and blue laser beams. The laser beam splitting unit includes a diffraction grating that spatially separates each of a plurality of laser beams having different wavelengths that are output simultaneously by a difference in diffraction angle depending on the wavelength,
The said detection means detects light intensity about each of the laser beam spatially isolate | separated for every wavelength with the said diffraction grating, respectively using a detection element for exclusive use. Inspection device. The laser beams having different wavelengths are infrared, red, and blue laser beams,
The inspection apparatus according to claim 4, wherein the diffraction grating spatially separates each of infrared, red, and blue laser beams. The inspection apparatus further includes
The inspection apparatus according to claim 4, further comprising: an optical system that collects each laser beam that has passed through the diffraction grating and guides the laser beam to a corresponding detection element. A method for inspecting a semiconductor laser that outputs a plurality of laser beams having different wavelengths,
A power feeding step of supplying a driving current between terminals for each wavelength of the laser light to be output, and simultaneously outputting the laser light of each wavelength to the semiconductor laser to be inspected,
A laser beam splitting step for splitting laser beams of a plurality of wavelengths output simultaneously from a semiconductor laser to be inspected for each wavelength;
A detection step for detecting the light intensity for each of the laser beams divided for each wavelength by the laser beam splitting step;
For each wavelength, a control step for controlling the drive current by the power feeding step so that the light intensity detected by the detection step maintains a predetermined value;
And a determination step for determining whether the semiconductor laser to be inspected is a non-defective product or a defective product by measuring a drive current for each wavelength. A method for inspecting a semiconductor laser that outputs a plurality of laser beams having different wavelengths,
In the initial stage of inspection, a drive current is sequentially supplied between terminals for each wavelength of the laser beam to be output, and each laser beam is sequentially output to the semiconductor laser to be inspected, and is output from the semiconductor laser for each wavelength. An initial step of controlling the drive current for each wavelength so that the detected light intensity maintains a predetermined value while measuring the light intensity of the laser light in a time-sharing manner, and measuring and holding the drive current for each wavelength; ,
In the middle stage of inspection, a medium step for supplying a fixed drive current between terminals for each wavelength of the laser light to be output and simultaneously outputting each laser light to the semiconductor laser to be inspected;
At the end of the inspection, a drive current is sequentially supplied between the terminals for each wavelength of the laser light to be output, and each laser light is sequentially output to the semiconductor laser to be inspected, and is output from the semiconductor laser for each wavelength. A final step of controlling the drive current for each wavelength so that the detected light intensity maintains a predetermined value while measuring the light intensity of the laser light in a time division manner, and measuring and holding the drive current for each wavelength; ,
For each wavelength, the value of the drive current held in the initial step is compared with the value of the drive current held in the final step, and the difference between these drive current values is determined whether the semiconductor laser to be inspected is a good product. And a determination step used for determining whether the product is defective.

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