JP2670385B2 - Micro illuminant observation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for observing a small light emitter for observing a light emitter in a laser diode or other object to be measured.

[0002]

2. Description of the Related Art Conventionally, two or more types of magnifying lenses are prepared in order to observe a light emitting state of a light emitting body (for example, a light emitting portion such as an active region of a laser diode) in an object to be measured such as a laser diode. , I had to replace this as needed. In other words, in order to observe the light emitting portion of the laser diode, a considerable magnification is required, and the observable region is limited to a certain extent. For this reason, the light emitting portion of the laser diode is once located in the observation area, that is, the center of the field of view, by means of a low magnification magnifying lens, and the light emitting portion of the laser diode is located. After that, the low magnification magnifying lens for positioning was replaced with a desired high magnification magnifying lens to obtain a magnified image of the light emitting portion of the laser diode.

[0003]

However, in the above-mentioned conventional example, it was difficult to match the optical axes of the high-magnification and low-magnification magnifying lenses. In other words, due to the deviation of the optical axis that originally exists in the high-magnification and low-magnification magnifying lenses and the deviation of the optical axis that occurs when the magnifying lens is replaced, the light-emitting portion that was at the center of the observation area at low magnification is In some cases, the image disappeared at a high magnification outside the observation region, and substantially magnified observation was not possible. Therefore, an object of the present invention is to provide a micro-illuminant observation apparatus capable of easily positioning a light-emitting portion or the like even when observing a light-emitting portion or a light-emitting portion at high magnification.

[0004]

In order to solve the above-mentioned problems, a micro-illuminant observation apparatus according to the present invention comprises: an imaging system for enlarging an image of a micro area to provide a first enlarged image; And an image pickup means for converting the light into a video signal, and observes the light emitting state of the light emitting body in the measured object. Here, the minute light emitter observing apparatus includes (a) an optical system that gives a second magnified image that is a magnified image of the object to be measured that is in a finder area that includes a minute area and is wider than that, and (b) a second magnified image. Is converted into light amount and position information, and position information is output by the position detecting means that outputs the position information of the light emitter in the second magnified image, and (c) the position information output by the position detecting means. And a control unit that controls the relative positional relationship between the objective lens of the imaging system and the object to be measured so that the light emitter moves within a very small area.

Further, in a preferred embodiment of the minute light emitter observing device of the present invention, the position detecting means detects the light amount information of the light emitter.

Further, in a preferred embodiment of the microscopic light emitter observing device of the present invention, a calculating means for giving a distribution curve of the light quantity of the object to be measured having an arbitrary section based on the video signal of the first magnified image, And a display means for displaying the distribution curve.

[0007]

According to the micro illuminant observation device of the present invention, it is possible to detect the position of the illuminant in the second enlarged image obtained by the optical system while observing the first enlarged image obtained by the imaging means. become. That is, the light emitter can be positioned in the first magnified image corresponding to the minute area based on the position information of the light emitter in the second magnified image corresponding to the wide finder area, so that the light emitter can be positioned accurately and quickly. A magnified image can be obtained.

Further, in a preferred embodiment of the above-mentioned minute light emitter observing device, the position detecting means detects and outputs the light amount information of the light emitter. Therefore, the brightness or the light amount of the enlarged image of the light-emitting body can be predicted to perform positioning, and excessive light can be prevented from entering the imaging means.

[0009]

Embodiments of the present invention will be described below.

FIG. 1 shows the structure of a microscopic light emitter observing apparatus of the embodiment. The image of the DUT 14 on the XY stage 13 is enlarged by the objective lens 2 which is an image forming system, and is split into two light beams by the half mirror 3. The hollow image formed by the light transmitted through the half mirror 3 is magnified again by the field lens 6 and the imaging lens 7, passes through the shutter 8, and is projected onto the imaging surface of the measurement TV camera 9. The first magnified image projected on the imaging surface of the measurement TV camera 9 can observe a light-emitting body (in the case of a semiconductor laser or the like, generally within a range of 1 to 2 μm in the case of a semiconductor laser). It is 600 to 1000 times. Therefore, the field of view of the first magnified image is extremely narrow, and the first magnified image can be obtained only in a limited minute area (10 to 20 μm square on the object to be measured) on the object to be measured 14. is there. First
The enlarged image is converted into a video signal by the measurement TV camera 9, and the control device 10 including a video signal memory, a CPU, and the like.
Is input to The video signal is appropriately image-processed by the control device 10 and displayed on the display device 11. As the image processing of the video signal, various treatments are possible, such as three-dimensional display of quantitative data of the light emission distribution of an arbitrary cross section of the light emitter as a light emission distribution curve.

On the other hand, the second magnified image formed by the light reflected by the half mirror 3 and passing through the lens 4 is projected on the light receiving surface of the position sensor 5 which is the position detecting means. The magnifying power of the second magnified image is sufficiently lower than the magnifying power of the first magnified image projected on the imaging surface of the measurement TV camera 9. Therefore, an image of a wide finder area (280 to 460 μm square on the object to be measured) including a minute area is projected on the light receiving surface of the position sensor 5. That is, the first magnified image corresponding to the minute area is
It forms a part of the second enlarged image corresponding to the finder area. In this case, the half mirror 3, the lens 4, the position sensor 5 and the like are fixed with respect to the objective lens 2 and the like, so that what is magnified at a predetermined position in the second magnified image is always the first magnified image. There is. Therefore, if the DUT 14 is moved relative to the objective lens 2 of the imaging system so that the light emitter moves to a predetermined position in the second magnified image,
The luminous body can be guided within the visual field of the measurement TV camera 9.

The position sensor 5 is composed of, for example, a PSD, and detects information about the position of the light emitter in the second magnified image and the total light amount thereof. The position sensor 5 is
It is driven by the power supply drive circuit 15, and its output is input to the control circuit 10. The control circuit 10 determines where the light emitter is projected on the position sensor 5 based on the output of the position sensor 5, and controls the stage drive circuit 16 so that the light emitter moves to a predetermined position in the finder area. It controls and operates the XY stage 13.

The operation of the minute light emitter observing apparatus of the embodiment will be described below.

An image of a limited finder area on the object 14 on the XY stage 13 is enlarged by the objective lens 2 and projected on the position sensor 5 as a second enlarged image. The control circuit 10 drives the XY stage 13 based on the output of the position sensor 5 to move the light emitter to a predetermined position in the finder area. As described above, since the finder area is 280 to 460 μm square and the position resolution of the position sensor 5 is 1/5000, the object to be measured can be positioned within the finder area with an error of 0.1 μm or less. it can. Therefore, considering that the luminous body is generally in the size range of 1 to 2 μm, the luminous body can be taken into the central portion of the minute area corresponding to the field of view of the measurement TV camera 9.

The image of the minute area including the illuminant is enlarged by the objective lens 2, the imaging lens 7, and the like, and projected on the imaging surface of the measurement TV camera 9 as a first enlarged image. This first
The enlarged image is converted into a video signal by the measurement TV camera 9, appropriately image-processed by the control device 10, and displayed on the display device 11.

In this case, the amount of light emitted from the light emitting body can be observed by the position sensor 5. Therefore, while observing the light emitter at the first magnification, the position sensor 5
It is also possible to observe the light emission amount of the light emitting body at the second magnification. Specifically, a semiconductor laser is used as the object to be measured, and its IL characteristics can be measured without changing the measurement system.

If the light emitter is observed before the light emitter is positioned, the brightness or the amount of light emission of the light emitter can be predicted and positioned, and excessive light is prevented from entering the measurement TV camera 9. it can. Specifically, the light emission amount of the light emitting body is determined based on the output of the position sensor 5 in a state where the light emitting body is out of the visual field of the measurement TV camera 9 or in a state where the shutter 8 in front of the measurement TV camera 9 is closed. Can be detected. Therefore, when the luminous intensity of the luminous body is large, the dotted line in the drawing indicates N
It is possible to prevent damage to the photocathode of the measurement TV camera 9 by inserting the D filters 18, 18 'and the like in the optical path of the light emitter image.

According to the above-described embodiment, since the position sensor made of PSD is used, an expensive image memory or image arithmetic processing unit is not required for detecting the position of the light emitter, the light emission amount and the like. Incidentally, PSD is an abbreviation for position sensitive detector (semiconductor light incident position detection element),
A semiconductor layer having a uniform resistance is formed on a substrate, and electrodes are provided on both ends of the semiconductor layer and other positions as necessary. The light incident on the semiconductor layer of this PSD generates carriers. The current resulting from the generated carriers is resistance-divided according to the incident position of light. That is, the incident position of light can be easily detected by comparing the currents drawn from the electrodes formed at both ends of the PSD (see Japanese Patent Publication No. 62-62074, etc.).

Further, since the position sensor made of PSD is used, it is possible to extremely stably and accurately detect the luminance center of gravity of the light emitter, the total light emission amount and the like.

Further, even if multi-mode laser light or ring-shaped light is generated from the light emitting body, the light emitting body can be positioned with respect to the center or the luminance center of the light emitting body. In this case, a complicated calculation for determining the center of the light emitter or the center of brightness is not required for positioning. Further, even when the light emitter is out of focus, the light emitter can be positioned with respect to its center.

The present invention has been described above with reference to the embodiments.
The present invention is not limited to the above embodiment.

For example, instead of the ND filter 18, a diaphragm or the like may be arranged to adjust the amount of light incident on the measurement TV camera 9. Further, the power supplied to the semiconductor laser that is the object to be measured may be controlled. Further, it is possible to use a light quantity adjusting means such as a liquid crystal filter or an optical wedge having low transparency.

The half mirror 3 for forming the second magnified image may be made movable by increasing the reflectance. That is,
The first magnified image and the second magnified image can be obtained by time division by periodically displacing the half mirror 3 between the position shown in the figure and the position retracted from the optical path of the first magnified image.

Further, an optical system separate from the objective lens 2 may be prepared for forming the second magnified image.

A solid-state image pickup device such as a CCD can be used as the position sensor 5. However, in this case, not only a special device such as an image memory is required, but also the light amount detection sensitivity is lowered. Further, since there is no substantial sensitivity between CCD elements, it is not suitable for positioning a minute light emitter. Further, the dynamic range of light amount detection is narrow, and when the light amount increases, blurring due to saturation may occur.

As the measurement TV camera 9, a vidicon, CC
D Other imaging devices can be used.

[0027]

According to the minute light emitter observing device of the present invention,
Since the position of the illuminant can be detected with the second enlarged image in a wider area while observing the first enlarged image, an enlarged image of the illuminant can be obtained accurately and quickly.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of a minute light emitter observation apparatus according to the present invention.

[Description of Signs] 2, 7 ... imaging means 9 ... imaging means 3, 4 ... optical system 5 ... position detection means 10, 16 ... control means

Claims (3)

(57) [Claims] 1. An imaging system for enlarging an image of a minute area to provide a first enlarged image, and an imaging unit for converting the first enlarged image into a video signal, wherein an image of the luminous body in the object to be measured is provided. A minute light emitter observing device for observing a light emitting state, comprising: an optical system which gives a second magnified image of an image of an object to be measured which is included in the finder area wider than the minute area, and the second magnified image. Is converted into light amount and position information, and position information is output by the position detection unit that outputs the position information of the light emitter in the second magnified image, and is enlarged by the imaging system based on the position information output by the position detection unit. A minute light emitter observing device, comprising: control means for controlling the relative positional relationship between the objective lens of the imaging system and the object to be measured so that the light emitter moves within the minute area. . 2. The minute light emitter observing device according to claim 1, wherein the position detecting means detects and outputs light amount information of the light emitter. 3. The image processing apparatus according to claim 1, further comprising: an arithmetic unit for providing a distribution curve of the light quantity of the object to be measured having an arbitrary cross section based on the video signal of the first enlarged image; and a display unit for displaying the distribution curve. The minute light emitter observation apparatus according to claim 1.