JP2003043100A - Photodiode characteristic inspection apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photodiode characteristics inspection apparatus which is compact, cheap and easy to handle and capable of efficiently and high accurately inspecting photodiodes under test by uniformly irradiating them with a high power inspecting laser beam. SOLUTION: A photodiode 2 under test is irradiated with an inspecting laser beam from a laser beam source 6 to inspect the photoelectric conversion characteristics and light intensity characteristics. A plurality of laser beam sources 6 are disposed on the mutually same plane against the photodiode 2 and a condenser lens 8 condenses the inspecting laser beams emitted from the laser beam sources 6 to irradiate the photodiode 2 with the beams distributed uniformly in the plane.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photodiode characteristic inspection device used in a manufacturing process of a photodiode having photoelectric conversion characteristics and the like.

[0002]

2. Description of the Related Art A photodiode has an opto-electrical conversion characteristic in which a reverse current and a current-voltage characteristic are changed depending on the intensity of light to be irradiated. It is widely used as a parameter detector for the wavelength and intensity of light. The photodiode is also provided in an optical pickup used in a disc recording / reproducing apparatus such as a compact disc (CD), and detects reflected laser light emitted from a laser source and reflected on the disc surface to convert a signal.

In general, photodiodes are subjected to various characteristic tests such as evaluation of current-voltage characteristics and measurement of parameters by changing light intensity with a fixed wavelength. Conventionally, an inspection apparatus 50 as shown in FIG. 2 has been used for such characteristic inspection. Inspection device 50
Includes a laser light source 51 disposed on one side, a photodiode 52 as an object to be inspected disposed on the other side, and a diffusion unit 53 disposed between the laser light source 51 and the photodiode 52. .

The diffusing unit 53 is a unit casing 54 formed of a light guide material in the shape of a prism, and a first diffusing unit which is assembled at one end of the unit casing 54 so as to face the laser light source 51. It is provided with a plate 55 and a second diffusion plate 56 mounted on the other end of the unit housing 54 so as to face the photodiode 52. In the inspection device 50, the photodiode 52 is mounted on the chucking member 58 which is movable on the rail member 57 installed on the optical axis of the second diffusion plate 56, so that the photodiode 52 and the second diffusion plate 56 are provided. The facing distance is adjusted. Although not shown, the inspection device 50 is provided with an output terminal for extracting the output signal from the photodiode 52 on the chucking member 58, and the output signal is measured by an appropriate measuring device connected via this output terminal. .

In the conventional inspection device 50, the inspection laser light emitted from the laser light source 51 is emitted from the first diffusion plate 5.
The light is guided to the inside of the unit housing 54 via 5. In the inspection device 50, the inspection laser light guided in the unit housing 54 irradiates the photodiode 52 via the second diffusion plate 56. In the inspection device 50, as shown in FIG. 2, the inspection laser light emitted from the laser light source 51 forming a so-called point light source is diffused by the first diffuser plate 55 and the second diffuser plate 56, so that the photo The light receiving surface of the diode 52 is uniformly irradiated with the inspection laser light. In the inspection device 50, the characteristic inspection is performed by measuring the output signal according to the intensity and wavelength of the inspection laser light output from the photodiode 52.

[0006]

In the conventional inspection device 50 described above, the inspection laser light emitted from the laser light source 51 is diffused by the first diffusion plate 55 and the second diffusion plate 56. It is possible to secure a uniform irradiation region of the inspection laser light in a wide range, but the light intensity per unit area becomes small, and precise measurement results cannot be obtained. Therefore, in the conventional inspection apparatus 50, the photodiode 52 has to be arranged closer to the second diffusion plate 56 in order to reduce the amount of attenuation in the optical path of the inspection laser light. .

Further, in the conventional inspection apparatus 50, in order to solve the above-mentioned problems, for example, by applying a high voltage to the laser light source 51, a measure to emit a high-output inspection laser beam is taken. There is a problem in that the control unit becomes complicated due to the increase in output and the high output, and more advanced safety measures are required, the size of the entire apparatus increases and the cost becomes extremely high. Further, in the conventional inspection apparatus 50, since the laser light source 51 and the photodiode 52 are fixedly provided, it is possible to continuously perform measurement and inspection of various photodiodes 52 having different wavelength characteristics and the like. It was difficult and the inspection efficiency was poor.

Further, in the conventional inspection device 50,
For example, when inspecting a photodiode 52 of a specification which is used for an optical pickup of a disk recording / reproducing apparatus or the like and has a wavelength of 780 nm and which is invisible to laser light, the irradiation state of laser light could not be confirmed. Therefore, the inspection device 50 expands the diffusion area of the first diffusion plate 55 and the second diffusion plate 56, and performs the preliminary inspection. Therefore, in the inspection device 50, there are problems that the light efficiency is further deteriorated and the adjustment operation is troublesome.

Therefore, according to the present invention, the photodiode of the object to be inspected is uniformly radiated with the high-intensity inspection laser beam so that the inspection can be performed with high accuracy and efficiency. It is an object of the present invention to provide a simple photodiode characteristic inspection device.

[0010]

A photodiode characteristic inspection apparatus according to the present invention which achieves the above-mentioned object emits an inspection laser beam from a laser light source to a photodiode to be inspected, and performs photoelectric conversion. Inspect characteristics and light intensity characteristics. The photodiode characteristic inspection device arranges a plurality of laser light sources on the same plane so as to face the photodiodes, and collects the laser light emitted from each laser light source by a condenser lens to the photodiode. The irradiation is performed so that the in-plane distribution is uniform.

Further, the photodiode characteristic inspection apparatus is
By irradiating the photodiode with reddish visible light by the condenser lens together with the laser light emitted from each laser light source, the irradiation position of each laser light on the photodiode can be confirmed. Further, the photodiode characteristic inspection device is configured such that each laser light source is replaceably attached to a light source attachment member arranged on one end side of the lens barrel so as to face the condenser lens. Furthermore, the photodiode characteristic inspection device is configured so that the focal position of the condenser lens can be adjusted corresponding to the set position of the photodiode.

According to the photodiode characteristic inspection apparatus of the present invention configured as described above, the in-plane distribution of the inspection laser light is uniform with respect to the photodiode to be inspected using a plurality of laser light sources as light sources. By irradiating so that the output of the inspection laser light is substantially increased, the characteristics of the photodiode such as the light-electricity conversion characteristics and the light intensity characteristics are inspected. A laser light source is unnecessary, simplification and improvement of safety can be achieved, and more accurate characteristic inspection can be performed.

Further, according to the photodiode characteristic inspection apparatus, by irradiating the photodiode with red-based visible light together with the inspection laser light, the wavelength of the inspection laser light is outside the visible light region such as 780 nm. Also in this case, since the irradiation position of the inspection laser beam can be visually confirmed, operations such as alignment can be facilitated and highly accurate characteristic inspection can be performed. Further, according to the photodiode characteristic inspection device, since the respective laser light sources can be exchanged, it is possible to easily cope with the characteristic inspection by the inspection laser light having different wavelengths, for example. Further, according to the photodiode characteristic inspection apparatus, the characteristic position of the photodiode having different specifications can be easily dealt with by making the focal position of the condenser lens adjustable.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention shown in the drawings will be described in detail below. A photodiode characteristic inspection device (hereinafter abbreviated as an inspection device) 1 irradiates a photodiode 2 which is an object to be inspected with an inspection laser light emitted from an inspection laser light projecting unit 3 as shown in FIG. To do. In the inspection apparatus 1, a measuring device (not shown) is connected to the photodiode 2, and the output from the photodiode 2 is supplied to this measuring device to measure and inspect the current-voltage characteristic or the wavelength and intensity characteristic of the incident inspection laser beam. . The inspection apparatus 1 includes a guide light projecting unit 4 for irradiating the photodiode 2 with a guide light of visible light in order to confirm the irradiation state of the inspection laser light by the inspection laser light projecting unit 3 on the photodiode 2. There is.

As shown in FIG. 1, the inspection apparatus 1 includes an inspection laser light projecting unit 3 having a unit housing 5 made of a metal cylindrical body. The light source attachment member 7 provided with the laser light source 6 is detachably attached, and the condenser lens 8 is attached to the other opening of the unit housing 5. The inspection laser light projecting unit 3 is formed by forming a light source mounting member 7 into a disc shape with a light-transmitting material. The four laser light sources 6 are provided on the main surface 7a of the light source mounting member 7 on the unit housing 5 side. They are located on the same circumference and are mounted at equal intervals.

In the inspection laser light projecting unit 3, each laser light source 6 is detachably attached to the light source mounting member 7, and outputs an inspection laser light having a predetermined wavelength according to the inspection specification of the photodiode 2. Will be exchanged as appropriate. The inspection laser light projecting unit 3 supplies power to each laser light source 6 mounted on the light source mounting member 7 from a control unit (not shown) via a cable 9. The inspection laser light projecting unit 3 adjusts the power supply under the control of the control unit, thereby adjusting the intensity of the inspection laser light output from each laser light source 6 according to the inspection specifications.

The inspection laser light projecting unit 3 guides the inspection laser light emitted from each of the laser light sources 6 to the tip side of the inside without exposing the outside by the unit casing 5. The inspection laser light projecting unit 3 is
By providing a plurality of laser light sources 6, inspection laser light having a sufficient light amount is emitted to irradiate the photodiode 2.

In the inspection laser light projecting unit 3, a condenser lens 8 is attached to the unit housing 5 in an exchangeable manner. Therefore, the inspection laser light projecting unit 3 can adjust the range of the uniform irradiation region of the inspection laser light by appropriately selecting the condenser lenses 8 having different focal lengths. This allows the inspection laser light projecting unit 3 to appropriately adjust the mounting position of the photodiode 2. In addition, the inspection laser light projecting unit 3 is mounted not only on the condensing lens 8 as an interchangeable lens but also on the unit casing 5 in an exchangeable manner, and may be mounted on the unit casing 5 as a lens unit having a focus adjusting mechanism, for example. You may

Since the inspection laser light projecting unit 3 emits the inspection laser light from each of the four laser light sources 6, the temperature inside the light source mounting member 7 may rise and the inspection laser may deteriorate. . Therefore, in the inspection laser light projecting unit 3, although not shown, an appropriate cooling mechanism is provided in the unit housing 5, or fins for heat dissipation (heat dissipation plate) are provided inside and outside the mounting portion of the light source mounting member 7. You may do it.

By the way, each laser light source 6 emits the inspection laser light emitted from each laser light source 6 by the Gaussian distribution measuring instrument with each elliptical irradiation area, and the light projecting unit 3 is provided. It is mounted and adjusted on the light source mounting member 7 so that the light is guided in the state of dispersed light inside. Therefore, the inspection laser beam projecting unit 3 condenses each of the parallel inspection laser beams into a certain irradiation area by the condenser lens 8 provided in the tip opening of the unit casing 5 as shown in FIG. And emit.

In the inspection apparatus 1, the photodiode 2 is installed on the center axis of the unit housing 5 of the inspection laser light projecting unit 3 by an appropriate chucking means. In the inspection apparatus 1, the photodiode 2 is specifically installed on the inspection laser light projection unit 3 side with respect to the focal length of the condenser lens 8. Therefore, in the inspection device 1, even when the facing distance between the inspection laser light projecting unit 3 and the photodiode 2 becomes large, the inspection laser light having a sufficient light amount by reducing the attenuation in the air is emitted from the photodiode 2. The entire light-receiving surface of is irradiated with a sufficient amount of light.

In the inspection apparatus 1, inspection laser light is emitted from the four laser light sources 6 and these inspection laser lights are crossed so that the in-plane distribution is uniform on the light receiving surface of the photodiode 2. In the inspection device 1, it is confirmed that the irradiation range is uniform by measuring the light amount on the light-receiving surface of the photodiode 2 with respect to each toleranced inspection laser light by, for example, a photometer. In the inspection device 1, when there is a variation in the irradiation range, a predetermined control operation of the laser light source 6 is performed via the control unit. In the inspection device 1, the light quantity is measured on the light receiving surface of the photodiode 2 by the light quantity meter, and if necessary, the predetermined laser light source 6 is supplied via the control unit.
Alternatively, a control operation is performed for all numbers.

When inspecting the characteristics of the photodiode 2 provided in a reproducing pickup device for a multipurpose optical disc (DVD) using a laser beam having a wavelength of 780 nm, the inspection device 1 emits a laser beam having a wavelength of 780 n from the laser light source 6.
m inspection laser light is emitted. It is difficult for the inspection device 1 to visually recognize whether or not the photodiode 2 is reliably irradiated because the inspection laser light is outside the visible light range and is slightly reddish. In the inspection device 1, as described above, the photodiode 2 is irradiated with the visible light from the guide light projection unit 4 so that the irradiation position of the inspection laser light can be visually recognized.

The guide light projecting unit 4 is arranged on the side of the second main surface 7b of the light source mounting member 7 so as to face the inspection laser light projecting unit 3 and have the central axes aligned with each other.
The guide light projecting unit 4 includes a guide unit housing 10 which is made of a metal bottomed cylindrical body and is detachably attached to the light source mounting member 7 at its one end on the opening side. It is composed of a light source 11 housed and a condenser lens 12.

As shown in FIG. 1, the guide light projecting unit 4 is mounted so that its central optical axis is aligned with the inspection laser light projecting unit 3. The guide light projecting unit 4 is provided with a light source 10 that emits, for example, red-colored visible light,
The light source 10 is located on the central optical axis of the condenser lens 8 of the inspection laser light projecting unit 3 and is housed in the guide unit housing 10. The guide light projecting unit 4 includes a condensing lens 12 and a condensing lens 8 of the inspection laser light projecting unit 3.
It is located on the central optical axis of, and is located between the light source 10 and the light source mounting member 7, and is housed in the guide unit housing 10.

The guide light projecting unit 4 is guided by turning on the light source 10 when the inspection light of the wavelength 780 nm is emitted from the laser light source 6 to inspect the characteristics of the photodiode 2. Emits light. The guide light projecting unit 4 collects the red guide light emitted from the light source 10 by the condenser lens 12 and guides it through the inside of the guide unit housing 10 to enter the light source mounting member 7. The red guide light is emitted from the light source mounting member 7
Is guided through the unit housing 5 through the condenser lens 8
Is focused on the central optical axis.

In the inspection device 1, the guide light projecting unit 4 emits the red guide light from the central optical axis of the condenser lens 8 so that the guide laser light projecting unit 3 outputs the red guide light. The central point of the inspection laser light emitted through the irradiation area of (1) is pointed to. Therefore, in the inspection device 1, by confirming the point position of the red-based guide light on the light receiving surface of the photodiode 2, it is possible to confirm the irradiation state of the photodiode 2 even if the inspection laser light is difficult to visually recognize. Is easily done. In the inspection device 1, the position adjustment operation of the photodiode 2 is extremely easily performed with reference to the point position of the red guide light.

In the above-described embodiment, the inspection device 1 is described as being used to inspect the photodiode 2 of the optical disk recording / reproducing pickup device, but the characteristics of the photodiode 2 used for various purposes are described. Of course, it is used for testing. In the inspection apparatus 1, the unit housing 5 of the inspection laser light projecting unit 3 and the guide unit housing 10 of the guide light projecting unit 4 are configured by separate members, but it is needless to say that they may be integrated.

[0029]

As described in detail above, according to the photodiode characteristic inspection apparatus of the present invention, the surface of each inspection laser beam is applied to the photodiode to be inspected using a plurality of laser light sources as light sources. By irradiating so that the inner distribution is uniform, the output of the inspection laser light can be substantially increased. Therefore, according to the photodiode characteristic inspection device, a large laser light source and a diffusion plate for homogenization are not required, and the photoelectric conversion characteristics and the photoelectric conversion characteristics of the photodiode can be reduced by downsizing and simplification and improving safety. The characteristic inspection such as the light intensity characteristic can be performed with high accuracy.

Further, according to the photodiode characteristic inspection apparatus, the wavelength of the inspection laser light is outside the visible light region such as 780 nm by irradiating the photodiode with the red visible light together with the inspection laser light. Even in such a case, the irradiation position of the inspection laser light is visually recognized, the position alignment operation of the inspection laser light is simplified, and highly accurate characteristic inspection is performed. Further, according to the photodiode characteristic inspection device, the characteristic inspection of the photodiode by the inspection laser light having different wavelengths can be easily dealt with by exchanging the respective laser light sources. Further, according to the photodiode characteristic inspection apparatus, the characteristic position of the photodiode having different specifications can be easily dealt with by making the focal position of the condenser lens adjustable.

[Brief description of drawings]

FIG. 1 is a configuration diagram of essential parts of a photodiode characteristic inspection apparatus shown as an embodiment of the present invention.

FIG. 2 is a main part configuration diagram of a conventional photodiode characteristic inspection device.

[Explanation of symbols]

1 Inspection device (photodiode characteristic inspection device) 2 photodiode 3 Inspection laser light projection unit 4 Guide light projection unit 5 unit housing 6 laser light source 7 Light source mounting member 8 Condensing lens 9 cables 10 Guide unit housing 11 visible light source 12 Condensing lens

Claims (4)

[Claims] 1. A photodiode characteristic inspecting apparatus for inspecting a photoelectric conversion characteristic and a light intensity characteristic by emitting an inspection laser beam from a laser light source to a photodiode as an object to be inspected, wherein a plurality of laser light sources are provided. Are arranged on the same plane as each other so as to face the photodiode, and the laser light emitted from each laser light source is condensed by a condenser lens so that the in-plane distribution is uniform with respect to the photodiode. A photodiode characteristic inspection device characterized in that irradiation is performed. 2. The irradiation position of each of the laser light with respect to the photodiode is confirmed by irradiating the photodiode with reddish visible light by the condenser lens together with each of the laser light emitted from each of the laser light sources. The photodiode characteristic inspection apparatus according to claim 1, wherein: 3. The laser light source is replaceably attached to a light source attachment member arranged on one end side of the lens barrel so as to face the condenser lens. 2. The photodiode characteristic inspection device described in 2. 4. The focus position of the condenser lens is configured to be adjustable corresponding to the set position of the photodiode.
Item 10. The photodiode characteristic inspection device according to item.