JPS63305257A - Voltage detecting apparatus - Google Patents

Abstract

PURPOSE:To obtain a desired detected result and to adjust an optical axis readily, by arranging a desired electrooptical material or a transparent material without an electrooptical effect at the tip part of an optical probe, so that the material can be replaced. CONSTITUTION:A rotary stage 2 is provided at the tip part of an optical probe 1. A plurality of screw holes 3-1, 3-2 and 3-3 are provided in the rotary stage 2. An electrooptical material 4-1 having an excellent temperature characteristic is coupled into the screw hole 3-1. An electrooptical material 4-1 having an excellent sensitivity characteristic is coupled into the screw hole 3-2. A transparent material 4-3 without an electrooptical effect is coupled into the screw hole 3-3. Before the voltage of a material to be measured 5 is measured, the rotary stage 2, which is provided at the tip part of the optical probe 1, is rotated. The transparent material 4-3 is positioned along the optical axis of the optical probe 1. A light beam is inputted, and the intensity of output light is judged. Thus the optical axis of the optical probe 1 is adjusted.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a voltage detection device for detecting the voltage of a predetermined portion of an object to be measured, such as an electric circuit, and particularly to a voltage detection device for detecting the voltage of a predetermined portion of an object to be measured, such as an electric circuit. The present invention relates to a type of voltage detection device that detects voltage by utilizing changes in the polarization state of light.

[Conventional technology]

Conventionally, various voltage detection devices have been used to detect the voltage of a predetermined portion of an object to be measured such as an electric circuit. This type of voltage detection device is of the type that detects the voltage at a predetermined portion of the object to be measured by contacting the probe with the predetermined portion of the object to be measured, or the type that detects the voltage of that portion by making the probe contact the predetermined portion of the object. Types that detect the voltage at certain points are known.

By the way, there is a desire among those skilled in the art to accurately detect the rapidly changing voltage of a minute part of an object to be measured, such as a small integrated circuit with a complex structure, without affecting the state of the minute part. There is a strong demand.

However, in a type of voltage detection device in which the probe is brought into contact with a predetermined part of the target object, it is not easy to bring the probe into direct contact with minute parts such as integrated circuits, and it is difficult to bring the probe into contact with minute parts such as integrated circuits. However, it is difficult to accurately analyze the behavior of an integrated circuit based only on the voltage information. Furthermore, there is a problem in that the operating state within the integrated circuit changes when the probe comes into contact with the integrated circuit.

In addition, with a voltage detection device that uses an electron beam, it is possible to detect voltage without bringing the probe into contact with the object to be measured, but this is limited to devices where the part to be measured is placed in a vacuum and exposed. There was also the problem that the part to be measured was damaged by the electron beam.

Furthermore, conventional voltage detection devices have a problem in that the operating speed of the detector cannot follow high-speed voltage changes, making it impossible to accurately detect voltages that change rapidly in integrated circuits and the like.

[Problem that the invention seeks to solve]

In order to solve such problems, the inventors have proposed a method that changes the polarization state of a light beam depending on the voltage at a predetermined portion of the object, as described in a patent application filed with El 57130 filed in 1988. A type of voltage detection device was developed that uses this method to detect voltage.

FIG. 4 is a schematic diagram of a voltage detection device of the type that detects the voltage of the object to be measured by utilizing the fact that the polarization state of the light beam changes depending on the voltage of a predetermined portion of the object to be measured.

In FIG. 4, the voltage detection device 50 includes an optical probe 52, a current light source 53 such as a laser diode, and an optical fiber that guides the light beam output from the DC light source 53 to the optical probe 52 via a condensing lens 60. 51, an optical fiber 92 that guides the reference light from the optical probe 52 to the photoelectric conversion element 55 via the collimator 90, and an optical fiber that guides the emitted light from the optical probe 52 to the photoelectric conversion element 58 via the collimator 91. 93 and photoelectric conversion element 55
．． The comparison circuit 61 compares the photoelectrically converted electrical signals from 58.

The optical probe 52 houses an electro-optic material 62, such as optical-axial crystal lithium tantalate (Li'ra03), and the tip 63 of the electro-optic material 62 is processed into a truncated conical shape. ing. A conductive electrode 64 is provided on the outer periphery of the optical probe 52, and a reflective mirror 65 made of a thin metal film or a dielectric multilayer is attached to the tip 63.

The optical probe 52 further includes a collimator 94, condensing lenses 95 and 96, a polarizer 54 for extracting only a light beam having a predetermined polarization component from the light beam from the collimator 94, and a predetermined polarization component from the polarizer 54. The electro-optic material 6 is split into a reference beam and an incident beam.
A beam splitter 56 is provided to make the emitted light from the analyzer 2 enter the analyzer 57. The reference light and output light are
Optical fibers 92 through condensing lenses 95 and 96, respectively.
．． 93.

In the voltage detection device 50 having such a configuration, during detection, the conductive electrode 64 provided on the outer periphery of the optical probe 52
For example, hold it at ground potential.

Next, the tip 63 of the optical probe 52 is brought close to an object to be measured, for example, an integrated circuit (not shown). As a result, the refractive index of the tip 63 of the electro-optic material 62 of the optical probe 52 changes. More specifically, in a light-axis crystal or the like, the difference between the lunar refractive index of ordinary light and the refractive index of extraordinary light in a plane perpendicular to the optical axis changes.

The light beam output from the light source 53 is passed through a condenser lens 60 .
Collimator 9 of optical probe 52 via optical fiber 51
The light beam enters the electro-optic material 62 of the optical probe 52 via the beam splitter 56, and is further converted into a light beam having a predetermined polarization component with an intensity l by the polarizer 54. Note that the intensity of the reference light and the incident light split by the beam splitter 56 is I/2. Electro-optical material f162
As described above, the refractive index of the tip 63 changes depending on the voltage of the object to be measured, so the polarization state of the incident light that enters the electro-optic material T162 changes depending on the change in the refractive index at the tip 63. The light reaches the reflecting mirror 65, is reflected by the reflecting mirror 65, and returns to the beam splitter 56 as an emitted light from the electro-optic material 62.

When the length of the tip 63 of the electro-optic material 62 is ρ, the polarization state of the incident light changes in proportion to the refractive index difference between the ordinary light and the extraordinary light due to the voltage and the length 2g.

The emitted light returned to the beam splitter 56 is sent to an analyzer 57.
incident on . Note that the intensity of the emitted light incident on the analyzer 57 is set to 1/11 by the beam splitter 56.

For example, if the analyzer 57 is configured to pass only a light beam with a polarization component perpendicular to the polarization component of the polarizer 54, the polarization state changes and the output that enters the analyzer 57 has an intensity of 1/4. The intensity of the emitted light is determined by the analyzer 57 to be (1
/4)sin2((π/2>·V/Vo), and is applied to the photoelectric conversion element 58. Here, V is the voltage of the object to be measured, and Vo is the half-wave voltage.

In the comparison circuit 61, the intensity 1/2 of the reference light photoelectrically converted in the photoelectric conversion element 55 and the intensity 2 (1/4) ・sin ((z/ 2) V
/V□] is compared.

Intensity of emitted light (I/4) ・sin 2((yrX
2) v/■o] is the electro-optic material v1 due to voltage change
It changes depending on the change in the refractive index of the tip 63 of 62, so
Based on this, it is possible to detect the constant voltage of M1, for example, the voltage of a predetermined portion of the integrated circuit.

In this way, in the voltage detection device 50 shown in FIG. 4, the refractive index of the tip η1 portion 63 of the electro-optic material 62 changes when the tip portion 63 of the optical globe 52 approaches the object to be measured. Since the voltage of a predetermined part of the object to be measured is detected, it is possible to detect the voltage of a minute part of an integrated circuit, which is difficult to contact, and which would affect the voltage to be measured if brought into contact. Detection can be performed without contacting the optical probe 52. In addition, a pulsed light source such as a laser diode that outputs light pulses with a very narrow pulse width may be used as a light source to sample the fast voltage changes of a By using a high-speed response detector such as a streak camera as a detector to measure high-speed voltage changes in the object to be measured with high time resolution, it is possible to detect even high-speed voltage changes with high accuracy.

By the way, for the user, by changing the type of optical probe or electro-optic material with one voltage detection device, it is possible to obtain detection results that give priority to temperature characteristics in some cases, and detection results that give priority to sensitivity characteristics in other cases. Sometimes you don't get results.

Furthermore, before detecting the voltage intermittently, the optical axis of the optical probe is adjusted by using a transparent material such as quartz glass that does not have an electro-optic effect instead of the electro-optic material, and this adjustment is completed. At this point, there are cases where it is desired to replace a transparent substance that does not have an electro-optic effect with an electro-optic material.

However, in the voltage detection device 50 shown in FIG.
Only one optical probe 52 is used and the optical probe 52
Since only one type of electro-optic material 62 is provided within the interior and there is no possibility of replacing the optical probe 52 or the electro-optic material 62 with another type, it is not possible to use it as described above. However, there is a lack of flexibility in obtaining detection results that are convenient for the operator or in adjusting the optical axis within the optical probe at the time of starting detection.

The present invention enables the user to obtain desired detection results and to adjust the optical axis of the optical probe to:J! The purpose of L1 is to provide a voltage detection device with a structure that allows easy adjustment.

[Means for solving problems]

The present invention provides an optical probe for bringing an electro-optic effect 1 close to a predetermined portion of the object in a type of voltage detection device using an electro-optic material whose refractive index changes depending on the voltage at a predetermined portion of the object to be measured. The tip of the optical probe is made of a desired electro-optic material or a transparent material with no electro-optic effect!
[Operation] The present invention aims to improve the above-mentioned problems of the prior art by using a voltage detection device characterized in that the IJ quality is replaceably arranged along the optical axis; A desired electro-optic material or a transparent material without electro-optic effect is placed at the tip of the tube along the optical axis. By placing an ineffective transparent material, it is possible to adjust the optical axis of the optical probe. Then, for example, by replacing it with an electro-optic material with good sensitivity characteristics, it is possible to detect the voltage at a predetermined part of the object with high sensitivity. Can be done.

〔Example〕

Embodiments of the present invention will be described below based on the drawings. 1 is a partial schematic configuration diagram of a first embodiment of a voltage detection device according to the present invention.

In the voltage detection device shown in FIG. 1, a rotary table 2 is rotatably provided at the tip of an optical probe 1.
Two screw holes 3-1.3-2.3-3 are provided.
An electro-optic material 4-1 having good temperature characteristics is fitted into the screw hole 3-1 of the rotary table 2, and an electro-optic material 4-2 having good sensitivity characteristics, for example, is fitted into the screw hole 3-2. A transparent material 4-3 such as quartz glass having no electro-optic effect is fitted into the screw hole 3-3.

In addition, electro-optical material 4-1.4-2. It is assumed that at the tip of the transparent material 4-3, which has no optical effect '7, a reflecting mirror made of a thin metal film or a dielectric multilayer film is formed, although not shown.

In the voltage detection device having such a configuration, before detecting the voltage at a predetermined portion of the object to be measured 5, the rotary table 2 provided at the tip of the optical probe 1 is rotated to detect the voltage as shown in FIG. A transparent material 4-3 having no electro-optic effect is positioned along the optical axis of the optical probe 1. After that, this transparent substance 4
A light beam having a predetermined polarization component is made incident on -3. By the way, since the transparent material M4-3 does not have an electro-optic effect, the polarization state of the incident light does not change within the transparent material 4-3, and therefore the polarization state of the light emitted from the transparent material 4-3 also changes. Since the polarization state is the same as that of the incident light, a detector (not shown) determines whether the intensity of the output light is the same as the intensity of the incident light, that is, the intensity of the reference light. The optical axis can be adjusted.

Next, when the user wants to obtain a detection result with good temperature characteristics, he rotates the rotary table 2 and inserts the electro-optic material f14-1 with good temperature characteristics along the optical axis of the optical probe 1. Position. Thereafter, a light beam having a predetermined polarization component is incident on the electro-optic material 4-1 as incident light, and a change in the polarization state of the light emitted from the electro-optic material f14-1 is detected. The voltage of a predetermined portion can be detected with good temperature characteristics. In addition, when the user wants to obtain a detection result with good sensitivity characteristics, the electro-optic material 4-2 with good sensitivity characteristics is positioned along the optical axis of the optical probe 1, and a predetermined portion of the measured object e15 is voltage can be detected with high sensitivity.

Further, in addition to the above-mentioned electro-optic material VI#14-1.4-2, an electro-optic material having a small dielectric constant and hardly disturbing the electric field to be measured may be used.

As described above, according to the first embodiment, by simply rotating the rotary table 2 at the tip of the optical probe 1, it is possible to very easily convert the electro-optic material 4-1, 4-2 or the transparent material 4 without electro-optic effect. -3 can be replaced, so it is possible to easily obtain detection results convenient for the user and to easily adjust the optical axis.

FIG. 2 is a schematic diagram of a partial unit 13 of a second embodiment of the voltage detection device according to the present invention.

In the voltage detection device shown in Fig. 2, a wedge-shaped r is attached to the optical probe lO.
l! 11 is provided, and a wedge-shaped portion 13 that fits into the lens 11 of the optical probe 10 is formed on the top of a crystal 12 of various types of electro-optic materials or electro-optic effects that can be replaced. It is assumed that, although not shown, a reflective mirror made of a metal thin film or a dielectric multilayer film is formed at the tip of the various electro-optical material or electro-optic effect crystal 12.

In such a configuration, a desired electro-optic material or a transparent material without electro-optic effect can be fitted to the lens 11 of the optical probe 10 to detect voltage or adjust the optical axis, and to perform other functions. When an electro-optical material or the like is used, the currently liquid electro-optical material fl can be removed and replaced easily.

In this way, in the second embodiment as well, the electro-optical materials etc. can be easily replaced, so that detection results convenient for the user can be easily obtained and the optical axis can be easily adjusted. be able to.

In the first and second embodiments, although not shown, a transparent electrode may be provided on the top surface of the replaceable electro-optical material. In this case, by applying a ground potential to the transparent electrode, the object to be measured can be The lines of electric force based on the voltage at a predetermined portion of are made parallel to the axis of the electro-optic material within the electro-optic material, so that changes in the refractive index within the electro-optic material fl become uniform, thereby increasing voltage detection accuracy. be able to.

Furthermore, although the replaceable electro-optic material has been described as being made entirely of electro-optic material, as shown in FIG. , the lower part may be formed of electro-optic material 15.

In addition, in the embodiment described above, the tip of the electro-optic material was explained as not coming into contact with the object to be measured, but the tip of the electro-optic N material was made to come into contact with the object to be measured. Also good.

〔Effect of the invention〕

As explained above, according to the present invention, a desired electro-optic material is attached to the tip of the optical probe. Transparent or non-electro-optical effects are arranged replaceably along the optical axis, making it easy for the user to obtain desired detection results and adjust the optical axis within the optical probe. This can be easily carried out and the flexibility of the voltage detection device can be significantly increased.

Further, it is possible to use a scale with a desired shape, such as a scale with a tapered tip that can measure v and fine parts, or a scale that can measure a large range.

[Brief explanation of drawings]

FIG. 1 is a partial schematic configuration diagram of a first embodiment of the voltage detection device according to the present invention, FIG. 2 is a partial mechanical diagram of the second embodiment of the voltage detection device according to the present invention, and FIG. 4 is a diagram showing a modified example of an electro-optic material that is replaceably attached to an optical probe, and FIG. 4 is a configuration diagram of a conventional voltage detection device. 1.10... Optical probe, 2... Turntable, 4-1.
/I-2...Electro-optical material, 4-3...Transparent substance without electro-optic effect 5...Measurement object, 11...Cancelled patent applicant Hamamatsu Botonics Co., Ltd. Agent Patent attorney Uemoto Masaharu Figure 1

Claims (1)

[Claims] 1) A type of voltage detection device using an electro-optic material whose refractive index changes depending on the voltage at a predetermined portion of the object to be measured,
Equipped with an optical probe for bringing an electro-optic material close to a predetermined part of the object to be measured, and a desired electro-optic material or a transparent substance without electro-optic effect can be replaced along the optical axis at the tip of the optical probe. A voltage detection device characterized in that it is arranged in. 2) The voltage detection device according to claim 1, wherein the electro-optical material replaceably arranged at the tip of the optical probe has a transparent electrode provided on its upper surface.