JPH02243966A - Voltage measuring instrument - Google Patents

Abstract

PURPOSE:To miniaturize a device and to lower the cost by interposing a light amplifier amplifying the light passing through an analyser between the analyser and a photoelectric conversion element. CONSTITUTION:A small-sized and low cost semiconductor laser is used for a laser beam source 10a, and the light amplifier 16 is interposed between a lens system 8b and a photodetector 12. The light passing through a light beam splitter 7 which is the analyser passes through the lens system 8b and is amplified to a sufficient level by the light amplifier 16, then subjected to photo-electric conversion by the photodetector 12, and an S/N of the detected signal S1 obtained therefrom is improved. Thus, the laser beam (l) with comparatively low intensity is enough for this application, and a voltage measurement with comparatively high accuracy is attained by using the semiconductor laser as the beam source 10a.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a voltage measuring device that measures voltage using an electro-optic crystal.

[Conventional technology]

When manufacturing and using semiconductor devices such as LSIs, it is essential to accurately measure signal waveforms inside and outside the device. Conventionally, electrical voltage measuring devices have been used for such measurements. ing.

However, as the speed of devices increases in recent years, it is becoming difficult to make accurate measurements using electrical voltage measurement devices such as LSI testers. Therefore, a voltage measurement device that uses the electro-optic effect of semiconductor element substrate crystals has been proposed. It has been confirmed that it is possible to measure high-speed signals (for example, J, A, Val
dsanls andG, morou '''5ubp
jcosecond electronles sai
ling:princlples and al)I
)licatiofl IEEE JOURNAL O
FQUANTUM ELECTRONIC9, VOL,
QE 22. pp, 6978, etc.).

This voltage δ! Since the 1-constant device uses a sampling method that maintains detection sensitivity while compensating for weak signal voltage changes by using high-intensity light from a high-output pulsed laser as a light source, it was inevitable that the device would become larger. .

Further, as another conventional example of a voltage measuring device, a voltage measuring device previously proposed by the inventors of the present invention and others is known, as shown in FIG.

In the figure, reference numeral 1 indicates an object to be measured whose voltage is measured in a characteristic test of an electronic processing device, etc., and reference numeral 2 indicates a power supply portion such as a terminal thereof.

Further, reference numeral 3 denotes a contact electrode made of aluminum, gold, etc., which is bonded to each power feeding portion 2, and allows crosstalk of the laser beam 1 to each power feeding portion 2.

The code 4 is a thin GaAs crystal (plane orientation [100), thickness 2
00 μm), etc., 5 is indium,
A transparent electrode made of tin and oxide.

The contact electrode 3, the electro-optic crystal 4, and the transparent electrode 5 are formed in a laminated manner, and when a voltage is applied between them, dielectric polarization occurs in the electro-optic crystal 4 due to the Pockels effect, resulting in a complex structure in which the refractive index changes depending on the axial direction. It has a refractive function.

Further, the reference numeral 6 is a quarter-wave plate, the reference numeral 7 is a deflection beam distributor, and the reference numerals 8g and 8b are lens systems, which are optical systems for converting the optical axis.

Reference numeral 9 denotes an X-Y deflector that scans the laser beam l on the power feeding portion 2 of the n1 fixed object 1, code 10 denotes a laser light source such as a YAG laser or semiconductor laser that emits the laser beam l, and code 11 denotes a laser light source such as a YAG laser or a semiconductor laser that emits the laser beam l. This is a drive control system that controls the XY deflector 9 and the laser light source 10.

The drive control system 11 can make the emission interval of the laser beam 1 into a pulse shape with the phase shifted by an integer fraction of one cycle of the voltage to be measured, depending on the frequency of the voltage of the object to be measured 1.

Further, the drive control system 11 can manually input the drive control signal S2 from the signal processing system 13 to drive and control the deflector.

Reference numeral 12 receives the amount of light, converts it photoelectrically, and generates a detection signal S.
Reference numeral 13 is a signal processing system that processes the detection signal S1, Reference numeral 14 is a measurement test control system that outputs a test signal S3 such as a clock signal to the object to be measured 11, Reference numeral 1
5 is the voltage measurement result.

With such a configuration, the laser beam 1 is scanned over one or more power feeding parts 2 in the object to be measured 1,
By utilizing the birefringence of the electro-optic crystal, the voltage of the power feeding portion 2 of the object to be measured 1 can be measured using light as a medium.

[Problem to be solved by the invention]

In this way, in the conventional voltage measuring device, by passing the measurement medium light l emitted from the light source 10 through the electro-optic crystal 4 placed under the influence of the voltage to be measured, the medium light 1 is By applying deflection angle modulation according to the voltage to be measured, guiding the light passing through the crystal to the analyzer 7, demodulating the modulated component as light intensity information, and guiding the light passing through the analyzer to the photoelectric element 12, It is configured to obtain an electrical signal according to the voltage to be measured.

However, when the n1 constant target voltage is weak, the degree of deflection angle modulation is also small, so a large and expensive high-intensity pulsed laser must be used as a light source to compensate for this, which increases the size of the entire device. There was a problem with the high price.

The present invention has been made in view of the above-mentioned problems, and its purpose is to enable miniaturization and cost reduction in this type of voltage measuring device.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a light source (10
By passing the n1 constant light (1) emitted from a) through an electro-optic crystal (4) placed under the influence of a constant target voltage, the measurement light is polarized according to the voltage to be measured. By applying angular modulation and guiding the light passing through the crystal to an analyzer (7), the modulated component is demodulated as light intensity information, and by guiding the light passing through the analyzer to a photoelectric element (12), Δ
-1 In a voltage 71 FI determining device that obtains an electrical signal according to a constant target voltage, an optical amplifier ( 16).

[Effect]

According to such a configuration, the analyzer (7) and the charge conversion element (
12), an optical amplifier (
16), even if the light passing through the analyzer is weak, the S/N ratio of the electrical signal finally obtained is good. There is no need for a pulse laser or the like, making it possible to downsize and lower the cost of the entire device.

〔Example〕

First example FIG. 1 shows a first embodiment of the invention.

Incidentally, in this figure, the same components as those of the conventional example shown in FIG.

The feature of this first embodiment device is that a generally small and low-cost semiconductor laser is used as the laser light source 10a, and an optical amplifier 16 is interposed between the lens system 8b and the light receiver 12. At the point.

In this example, as the optical amplifier 16, a semiconductor laser element whose both end faces are subjected to anti-reflection treatment is used.

According to the above configuration, the light passing through the optical beam splitter 7, which is an analyzer, passes through the lens system 8b and is amplified to a sufficient level by the optical amplifier 16, and then photoelectrically converted by the optical receiver 12. The S/N ratio of the detection signal S1 obtained from the detection signal S1 is improved.

Therefore, the laser beam 1 only needs to be of relatively low intensity, and even though a semiconductor laser is used as the laser light source 10a, relatively accurate voltage measurement is possible.

Second example Next, FIG. 2 shows a second embodiment of this invention.

In this figure, the same components as those in FIG.

The feature of this second embodiment device is that, in addition to the configuration of the first embodiment shown in FIG. .

According to the above configuration, the amplification characteristic when the optical amplifier 16 and the supersaturable absorber 17 are viewed as one unit becomes a nonlinear amplification characteristic as shown in FIG. 3.

Generally, the light passing through the optical beam splitter 7, that is, the reflected light, contains a C component that is large compared to the change in the light amount, and when a highly sensitive light receiver 12 is used, saturation etc. There is a possibility that distortion may occur in the detection signal S1 due to the influence.

Therefore, if the nonlinear amplification characteristics are set so that the DC component described above coincides with the rising portion shown in the graph of FIG. 3, it is possible to selectively amplify only the signal component. In addition to improving the /N ratio, signal distortion can also be improved.

〔Effect of the invention〕

As described above, according to the present invention, by interposing an optical amplifier that optically amplifies the light passing through the analyzer between the analyzer and the photoelectric conversion element, a small and low-cost light source such as a semiconductor laser element is used as a light source. This kind of voltage is available at a low price
This makes it possible to downsize and lower the cost of fixed equipment.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a first embodiment of the present invention, FIG. 2 is a block diagram of a second embodiment of the present invention, FIG. 3 is an explanatory diagram of nonlinear amplification characteristics in the second embodiment, and FIG. 1 is a block diagram showing an example of a conventional voltage measuring device. 1...Covered? l-1 constant object 2...power supply part 3...contact electrode 4...electro-optic crystal 5...transparent electrode 6...1/4 wavelength plate 7...light beam splitter 8a, 8b ... Lens system 9 ... XY deflector 10.10a ... Laser light source 11 ... Drive control system 12 ... Light receiver 13 ... Signal processing system 14 ... Measurement test control system 15. ...Measurement result 16...Optical amplifier 17...Supersaturated absorber Sl...Detection signal S2...Control signal S3...Test signal 'l! Measurement vs. Song Dynasty 1 Object to be measured 1 Book diagram of the first example of the present invention Figure 1 Professional diagram of the second embodiment of the present invention Figure 2

Claims (1)

[Claims] By passing the measuring light (1) emitted from the light source (10a) through an electro-optic crystal (4) placed under the influence of the voltage to be measured, the measuring light is subjected to measurement. By applying polarization angle modulation according to the target voltage and guiding the light passing through the crystal to an analyzer (7), the modulated component is demodulated as light intensity information, and the light passing through the analyzer is guided to a photoelectric element (12). In the voltage measuring device which obtains an electric signal according to the voltage to be measured by this, an optical amplifier ( 16) A voltage measuring device characterized by intervening.