JP2002014031A - Measuring apparatus for physical quantity - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measuring apparatus which prevents the surface of a photo sensitive sample from ending up unwillingly irradiated with a light emitted from a light source, when a part of the light is scattered, and which easily aligns the position of the light emitted from the light source prior to measurement. SOLUTION: This measuring apparatus is provided with a spring, to which a probe is attached, a light source 25 for measurement which radiates a light with a wavelength at which the sample is not photosensitive, when the bend or the vibration of the spring due to a force acting between the probe and the surface of the sample arranged so as to face the probe or a change in the vibration is detected by using an optical technique to measure the physical quantity of a light source 28 for adjustment which radiates visible light, a position which is irradiated with the light from the light source 25 is irradiated with the visible light, and a light-receiving element which is sensitive to the wavelength at which the sample is not photosensitive.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a physical quantity measuring device used for a scanning force microscope, a high-resolution surface potential shape measuring device, and a device for measuring the surface potential of a photosensitive drum, toner shape and toner potential distribution. About.

[0002]

2. Description of the Related Art Conventionally, the state of a sample surface (potential, shape, etc.)
Various devices have been proposed as physical quantity measuring devices for measuring the temperature. FIG. 14 shows a basic configuration for measuring the bending of the cantilever 1 using an optical method based on a so-called optical lever method. In this case, the light emitted from the light source 4 is applied to the reflection mirror 5 on the surface opposite to the surface on which the probe 2 at the tip of the cantilever 1 is formed, and the light reflected by the reflection mirror 5 is received. It is led to the element 6. In such a state, the bending or vibration of the spring changes according to the force acting between the probe 2 and the surface of the sample 3. Then, the light is reflected by the reflecting mirror 5 on the cantilever 1 according to the change,
The position of the light reaching the light receiving element 6 moves, and the light receiving element 6 detects the movement, whereby the force acting on the cantilever 1 can be measured. The optical lever optical system including the light source 4, the reflection mirror 5, and the light receiving element 6 requires a certain optical path length, and the entire optical system tends to be large. Therefore, when measuring the two-dimensional distribution of the surface state of the sample, the optical system itself is not scanned, and the measurement is performed by scanning the stage 7 on which the sample 3 is placed. .

The example shown in FIG. 15 (see Japanese Patent Application Laid-Open No. 5-256641) shows a small-sized cantilever displacement detecting device using a leverage method with high sensitivity. In this case, the size of the entire optical system is reduced by disposing the light source 4 near the cantilever 1 and increasing the optical path length by the mirrors 8 and 9. This makes it possible to cope with the measurement of a large sample such as a photosensitive drum.

The example shown in FIG. 16 (see Japanese Patent Application No. 5-93499) shows an example of an apparatus for measuring the potential and the shape of the surface of a sample 3 (photosensitive drum). In this case, light emitted from the light source 4 (semiconductor laser) is reflected by the reflection mirror 5 attached to the back surface of the tip of the cantilever 1 and detected by the light receiving element 6 by the so-called optical lever method. The detected signal is output by the preamplifier 10 as an output Vo. Thereafter, the voltage V ₂₁ , which is the output value from the integrator 12, and the AC voltage V
_31, an AC voltage V ₃₂ of the sine wave AC power source 14 is applied. The voltage V ₄₁ from the adder 11 is
The voltage V ₅₁ from the power amplifier 15 is applied to the probe 2 of the cantilever 1. The voltage V ₅₁ is cantilever 1 of the resonance frequency omega ₀ and its half frequency omega _0/2
And the DC bias voltage Vb (= GV ₂₁ ) are superimposed on the AC voltage Va ｛= G (V ₃₁ + V ₃₂ )} having the following. The voltage V ₅₁ is applied to the cantilever 1, a resonance frequency ω
₀ detects a difference between the (potential with respect to the ground potential) voltage Vs of the DC bias voltage Vb and the sample surface from the amplitude of the resonant oscillation of the cantilever 1 caused by, controlling the DC bias voltage Vb so that this difference becomes 0 Then, the surface potential of the sample 3 is measured from the value of Vb. On the other hand, the frequency ω ₀
/ 2, the distance d between the tip of the probe 2 and the surface of the sample 3 is measured, and the Z-axis actuator 16 is supplied with a voltage from the power amplifier 17 so as to keep the value of the distance d constant. by driving controlled by V _52, to measure the surface shape of the sample 3 from the voltage V ₂₂ is a control signal for the Z-axis actuator 16. Thus, the surface potential and the surface shape of the sample 3 can be measured simultaneously and independently.

[0005]

In the apparatus shown in FIG. 15, a light source 4 (such as a laser diode) is arranged near the cantilever 1 to reduce the size of the entire optical system. In this case, since the light source 4 must always be driven with a stable constant current, a laser drive circuit (not shown) for driving the light source 4 is required.
Is required on the optical system side. However, arranging such a laser drive circuit on the optical system side increases the configuration of the entire optical system and increases the weight, and particularly for scanning a large sample by moving the cantilever 1 and the optical system. Disadvantageous.
Therefore, there is a method in which the laser drive circuit is not disposed directly on the optical system side, but is disposed at another remote location, and power is supplied to the light source 4 from that location via electric wiring. However, such a method poses a serious problem when measuring a high-voltage surface potential with a scanning force microscope. That is, during the measurement of the high voltage surface potential, a discharge accompanied by a spark may occur between the probe 2 and the surface of the sample 3 or between the probe 2 and a peripheral device (not shown). Electromagnetic noise is generated by such spark discharge, and a surge current flows through the electric wiring between the laser drive circuit and the light source 4 due to the electromagnetic noise. In the worst case, the light source 4 is destroyed.

When force detection is performed by the optical lever method as in the example of FIG. 16, not all light emitted from the light source 4 is guided to the light receiving element 6 but a part of the light is scattered. The surface of the sample 3 is irradiated. In the case where a photosensitive material (photosensitive drum) is used as the sample 3 as in this example, the surface of the drum is exposed by the leaked light, and the surface charge is discharged. Latent image)
Will be disturbed.

Further, in order to accurately measure the bending and vibration of the cantilever 1 using an optical method, the light emitted from the light source 4 is accurately applied to the tip of the cantilever 1. Therefore, it is necessary to perform alignment for irradiation of light before measurement. However, the wavelength of the light used for the light source 4 is not in the visible region but in the infrared or ultraviolet region.
For this reason, it is impossible to align the light emitted from the light source 4 with the naked eye. In addition, although infrared image converters that visualize the emission of infrared light are commercially available,
Low sensitivity and insufficient for practical use.

In FIG. 16, a probe 2 and a sample 3
An electrostatic attraction is applied to the surface of the (photosensitive drum). The potential difference is V ₁ , the distance is d ₁ , and the equivalent area of the tip of the probe 2 facing the drum surface. the When S _1, the force F ₁ acting between the probe 2 and the drum _{surface, F 1 = S 1 ε 0} (V 1 2 / d 1 2) ... (1) However, epsilon _0: dielectric air It can be expressed as a ratio. On the other hand, the cantilever 1 having the same potential as the probe 2 is supported by the base 18.
A support mechanism (peripheral device) for supporting these components is provided around the device, and such a support mechanism is at a ground potential for noise shielding. For this reason, an electrostatic attraction also acts between the cantilever 1 and the supporting mechanism around it. Assuming now that the potential difference between the _two is V ₂ , the equivalent distance is d ₂ , and the equivalent area is S ₂ , the force F _{2 in} this case is: F ₂ = S ₂ ε ₀ (V ₂ ² / d ₂ ² )… (2) Here, comparing F ₁ and F ₂ in the equations (1) and (2), d ₁ ≪d ₂ , but the area S ₂ is the cantilever 1
A back side, the S ₂ »S _1. Further, while the potential of the probe 2 and the potential of the drum surface are substantially equal in configuration, the potential of the peripheral support mechanism is always the ground potential. Therefore, when the potential of the drum surface is high, the value of V ₂ is high. Becomes larger, so that V ₁ ≪V ₂ . Accordingly, this reason, the force F ₂ is the environmental conditions peripheral force F ₁
Is a value that cannot be ignored, and this value causes a measurement error.

[0009]

According to the first aspect of the present invention, there is provided a spring having a probe attached thereto, wherein the spring is provided by a force acting between the probe and a surface of a sample arranged opposite thereto. In a physical quantity measurement device that measures the physical quantity of the sample by detecting the bending or vibration of the spring or a change in the vibration using an optical method, a measurement light source that emits light having a wavelength at which the sample is not exposed, and a visible light A light source for adjustment, which emits visible light at a position where the measurement light source is irradiated at the time of measurement, and has a sensitivity to a wavelength at which the sample is not exposed.

According to the first aspect of the present invention, since the visible light emitted from the adjusting light source is applied to the cantilever,
The irradiation position on the cantilever can be adjusted with the naked eye, and light having a wavelength at which the sample emitted from the measurement light source is insensitive can be guided to the irradiation position after the adjustment. become. By using the adjustment light source that emits visible light, the irradiation position of the cantilever can be adjusted with the naked eye.

According to the second aspect of the present invention, there is provided a spring having a probe attached thereto, and the spring bends or vibrates due to a force acting between the probe and the surface of the sample arranged opposite thereto. In a physical quantity measurement device that measures a physical quantity of the sample by detecting a change in vibration using an optical method, a measurement light source that emits light having a wavelength at which the sample is not sensitive, and a sensitivity at a wavelength at which the sample is not sensitive. And a wavelength conversion member for converting light emitted from the measurement light source into visible light, in addition to a portion on the spring to which light emitted from the measurement light source is irradiated.

According to the second aspect of the present invention, the light emitted from the light source and having a wavelength at which the sample is insensitive is applied to the wavelength conversion member on the cantilever so that the irradiated position is changed to visible light. Thus, the physical quantity can be measured without disturbing the state of the sample, and the irradiation position of the cantilever can be easily adjusted.

According to the third aspect of the present invention, there is provided a spring having a probe attached thereto, and the spring bends or vibrates or is caused by a force acting between the probe and the surface of the sample disposed opposite to the probe. In a physical quantity measurement device that measures a physical quantity of the sample by detecting a change in vibration using an optical method, a measurement light source that emits light having a wavelength at which the sample is not sensitive, and a sensitivity at a wavelength at which the sample is not sensitive. Having a light-receiving element having a shielding member that covers a part or the whole area excluding the probe area of the spring, and a wavelength conversion member that converts light of the measurement light source into visible light on the shielding member. Provided.

According to the third aspect of the present invention, the light emitted from the light source and having a wavelength at which the sample is insensitive is irradiated to the wavelength conversion member on the shielding member disposed above the cantilever, The irradiated position can be illuminated with visible light, which allows measurement of physical quantities without disturbing the state of the sample and facilitates adjustment of the irradiation position of the cantilever. Further, it is possible to eliminate restrictions on designing and manufacturing the cantilever.

According to the fourth aspect of the present invention, there is provided a spring having a probe attached thereto, and the spring bends or vibrates due to a force acting between the probe and the surface of the sample arranged opposite thereto. In a physical quantity measurement device that measures a physical quantity of the sample by detecting a change in vibration using an optical method, a measurement light source that emits light having a wavelength at which the sample is not sensitive, and a sensitivity at a wavelength at which the sample is not sensitive. A light-receiving element having a shielding member formed of a conductive material having a higher rigidity than the spring that covers a part or all of the spring except for a probe region of the spring. Was provided with a wavelength conversion member for converting the light of the measurement light source into visible light, and a shielding member having this wavelength conversion member was set to the same potential as the spring and the probe.

In the invention according to the fourth aspect, the light emitted from the light source and having a wavelength to which the sample is not sensitive is irradiated to the wavelength conversion member on the shielding member disposed above the cantilever, The irradiated position can be illuminated with visible light, which allows measurement of physical quantities without disturbing the state of the sample and facilitates adjustment of the irradiation position of the cantilever. In addition, it is possible to eliminate restrictions on the design and manufacture of the cantilever, and furthermore, since the shielding member is formed of a conductive material having high rigidity, and the cantilever and the shielding member are set to the same potential, It is possible to reduce the electrostatic attractive force acting between the beam and the peripheral device.

According to the fifth aspect of the present invention, there is provided the first, second, and third aspects.
In the invention described in 3 or 4, the emission wavelength of a light source to which the sample is not exposed is set to a value of 400 nm or less, or 600 nm or more.

In the fifth aspect of the present invention, a photographic material frequently used as a photographic material is a photographic material having a photosensitivity of 400.
Since it is near 400 nm and near 600 nm, a photosensitive material sample near 400 nm has a thickness of 600 nm.
By using a light source having an emission wavelength of at least 600 nm and using a light source having an emission wavelength of 400 nm or less for a sample of a photosensitive material near 600 nm, the state of the sample may be disturbed by light from the light source. Disappears.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. The conventional example described above (FIG. 14)
16) are omitted, and the same reference numerals are used for the same portions.

[Overall Configuration] A probe 2 is attached to the tip of a cantilever 1 serving as a spring, and a sample 3 (photosensitive member) used for high-voltage surface potential measurement is provided at a position facing the probe 2. Drum etc.) are arranged. On the back side of the probe 2 of the cantilever 1, an optical system and a measuring circuit using the optical lever method similar to the above-described conventional example (see FIG. 16) are provided.
On the back side of the probe 2 of the cantilever 1, an optical fiber 19 (single mode fiber) is arranged as an optical waveguide. A selfoc lens 20 as an emission section is attached to one end of the optical fiber 19, and the selfoc lens 20 is disposed opposite to a position close to the reflection mirror 5 provided on the back surface of the cantilever 1. I have.
In this case, the optical fiber 19 and the Selfoc lens 20 constitute an optical transmission unit 21.

The other end of the optical fiber 19 is inserted into a shield box 22 and connected to an optical fiber coupler 23. On the optical path of the optical fiber coupler 23, a selfoc collimating lens 24 and a laser diode 25 (hereinafter, referred to as LD) as a light source for measurement are sequentially arranged, and the LD 25 has a driving laser drive circuit 26 ( Hereinafter, an LD drive circuit is connected. In this case, the LD driving circuit 26, the LD 25, the selfoc collimating lens 24, and the optical fiber coupler 2
Reference numeral 3 denotes a laser diode unit 27 as a light source unit.

The operation of such a configuration will be described. Light emitted from the LD 25 in the shield box 22 is condensed by the selfoc collimating lens 24, and is transmitted through the optical fiber coupler 23 to the optical fiber 19.
Is optically coupled within. The coupled light travels through the optical fiber 19, is guided to the external space, and is irradiated from the selfoc lens 20 at the end of the optical fiber 19 toward the reflection mirror 5 on the back surface of the cantilever 1. You. The light reflected by the reflection mirror 5 is detected by the light receiving element 6 (PSD) by a so-called optical lever method, and output as an output Vo by the preamplifier 10. Subsequent processing is performed in the same manner as in FIG.

As described above, the use of the optical fiber 19 allows the distance between the cantilever 1 and the LD 25 to be at least 1 m or more. Therefore, probe 2
Even if a spark discharge or the like occurs between the sample and the high voltage measurement sample 3 or a peripheral device, the generated electromagnetic noise is not transmitted to the LD 25 through the optical fiber 19, and the laser diode unit Since the location where the spark is generated is separated from the location where the spark is generated, a surge current does not flow in the current for driving the LD 25, and the LD 25 itself is hardly destroyed. Thereby, highly reliable measurement can be performed. in this case,
By covering the entire periphery of the LD 25 with a shield box (not shown), the influence of electromagnetic noise can be further reduced.

The optical fiber 19 has excellent flexibility. The SELFOC lens 20 generally has a diameter of 3 to
Since it is about 5 mm and 10 mm in length, it is made of a very light material. For this reason, by moving the selfoc lens 20, the cantilever 1 and the light receiving element 6 integrally, scanning can be performed while the sample 3 is fixed, thereby making it possible to perform a large sample. Can also be measured.

The lens used in the shield box 22 is not limited to the selfoc collimating lens 24, but may be any lens having the same characteristics. The selfoc lens 20 attached to the optical fiber 19 may be a general lens as long as it is small. Further, the optical fiber 19 is not limited to a single mode fiber, but may be a multimode fiber.

[Photosensitive Drum] In this embodiment, the case where the sample 3 is made of a photosensitive material such as a photosensitive drum used in an electrophotographic apparatus will be described. The measurement light source (such as the LD 25) emits light in a wavelength region where the sample 3 is not exposed. Light receiving element (light receiving element 6)
Has a sensitivity at a wavelength to which the sample 3 is not exposed. Hereinafter, description will be given with specific numerical values.

FIG. 2 shows the spectral sensitivity of a well-known typical photosensitive drum used in an electrophotographic apparatus. Thus, at around 400 nm, Se and a mixture of zinc sulfide and cadmium sulfide have particularly high sensitivity. In the vicinity of 600 nm, LPC (Layere
d Photo Conductor) chloro about 0.1 μm thick chlorodiane b
membrane CGL (Char) of a mixture of lue and diphenylhydrazone
CTL (Cha) about 15 μm
rge Transport Layer) has a particularly high sensitivity. The organic photoreceptor (polyvinylcarba
zole and trinitrofluorenone in a ratio of 1: 1 and positively charged) have sensitivity around 600nm,
Organic photoreceptor (similar to negatively charged substance)
Has a sensitivity in the range of 400 nm to 600 nm.

This indicates that the photosensitive drum has no sensitivity to light having a wavelength of 600 nm or more. Therefore, for this reason, a light source for measurement that emits light having a wavelength of 600 nm or more and a light receiving element having sensitivity at a wavelength of 600 nm or more are used. In addition, from the viewpoint of giving a certain margin to the spectral sensitivity, a light source and a light receiving element made of a material corresponding to light having a wavelength of 900 nm or more are preferably used. Materials for the light source and the light receiving element corresponding to the wavelength of 900 nm or more include those shown in Tables 1 and 2 below.

[0029]

[Table 1]

[0030]

[Table 2]

As the material of the light source and the light receiving element corresponding to the wavelength of 600 nm or more, in addition to the light source and the light receiving element corresponding to the wavelength of 900 nm or more, those shown in Tables 3 and 4 below are used. is there.

[0032]

[Table 3]

[0033]

[Table 4]

Further, in FIG. 2, since the substance is low in sensitivity to a wavelength of 400 nm or less, a light source having a wavelength of 400 nm or less and a light receiving element having sensitivity to this wavelength are used. Materials for the light source and the light receiving element corresponding to the wavelength of 400 nm or less include those shown in Tables 5 and 6 below.

[0035]

[Table 5]

[0036]

[Table 6]

As described above, the light emitting element and the light receiving element whose light emission wavelength and the wavelength having the spectral sensitivity match from the various materials of the light source and the light receiving element using light of the wavelength which does not have the spectral sensitivity of the photosensitive member. To form an optical lever optical system (in FIG. 1, composed of the LD 25, the optical fiber 19 having the Selfoc lens 20, the reflecting mirror 5, and the light receiving element 6), Thus, the state of the electrostatic latent image at the time is not disturbed, whereby the measurement of the surface potential or the like can be accurately performed without measuring errors. Although the optical lever optical system has been described,
The present invention can also be applied to a case where the state of a sample is measured by detecting the deformation or vibration of a cantilever by an optical interference method.

[Outline of Light Source] As shown in FIG. 3, an infrared laser diode having an emission wavelength of 1310 nm is used for the LD 25 as a light source for measurement. Also, here
Laser diode 2 as adjustment light source that emits visible light
8 (hereinafter, referred to as LD). This LD2
As 8, a visible light laser diode having a wavelength of 670 nm is used. This LD 28 is driven by a laser drive circuit 29.

On the optical paths of the two LDs 25 and 28, collimating lenses 30 and 31 are arranged, respectively. An optical coupler 32 is provided at a position where these two optical paths intersect. A focus lens 33 is disposed between the optical coupler 32 and the optical fiber coupler 23 to which the optical fiber 19 is connected. In this case, LD
The drive circuits 26 and 29, the LDs 25 and 28, the collimator lenses 30 and 31, the optical coupler 32, the focus lens 33, and the optical fiber coupler 23 constitute a laser diode unit 27.

FIG. 4 shows a state in which the present apparatus is constructed using the laser diode unit 27 of FIG. A stage 34 for adjusting the irradiation position is attached to the SELFOC lens 20 at the tip of the optical fiber 19. The light receiving element 6 has an X stage 3 that can move the element in the X direction.
5 are attached.

Hereinafter, the operation of the present apparatus will be described. First, the laser driving circuit 26 is turned off, and the laser driving circuit 2 is turned off.
9 is turned on, and only the LD 28 emits visible light.
This visible light is collimated by the collimating lens 31,
The light is condensed by the focus lens 33 via the optical coupler 32, and is introduced into the optical fiber 19 from the optical fiber coupler 23. The introduced light passes through the optical fiber 19, exits from the self-fox lens 20 at the tip, and irradiates the reflection mirror 5 at the tip of the cantilever 1. Since the wavelength of the irradiated light is 670 nm and is within the range of the visibility 36 as shown in FIG. 5, the irradiation position can be confirmed with the naked eye or using an optical microscope. Therefore, from such a situation, using the stage 34 attached to the SELFOC lens 20,
The light irradiated on the cantilever 1 can be adjusted to a desired position on the reflection mirror 5. Further, the light reflected from the cantilever 1 travels toward the light receiving element 6. Also in this case, while observing the reflected light with the naked eye, the position of the light receiving element 6 is adjusted using the X stage 35 so that the light enters a predetermined position of the light receiving element 6.

After adjusting the position on the cantilever 1 and the light receiving element 6 where the light is irradiated by using the visible light, the laser drive circuit 29 is turned off during the actual measurement.
The laser drive circuit 26 is turned on, and only the LD 25 emits infrared light. As a result, the infrared light is guided to the optical fiber 19 in the same manner as in the case of visible light, emitted from the selfoc lens 20, and applied to a predetermined position of the reflection mirror 5 on the cantilever 1. The light is reflected by the cantilever 1 and guided to a predetermined position of the light receiving element 6 by a so-called optical lever method. At this time, the selfoc lens 20 and the cantilever 1
And the positional relationship between the light receiving element 6 and the light receiving element 6 are set in the same state as when the alignment is performed by the visible light, so that the optical axis through which the infrared light passes is equal to the optical axis through which the visible light passes,
The infrared light is applied to the position where the alignment is performed by the visible light. By the method as described above, the alignment of the infrared light irradiated onto the cantilever 1 and the alignment of the incident light to the light receiving element 6 can be easily performed by visible light that can be confirmed with the naked eye. Accordingly, the displacement and vibration of the probe 2 can be accurately measured without including a measurement error.

[Details of Light Source] Here, the optical fiber 19 as described above is not used, and the light for measurement from the LD 25 or the visible light from the LD 28 passes through the output side of the optical coupler 32. An emission window 37a for causing
A focus lens 37 is attached to the exit window 37a. Thereby, the laser diode unit 27
Is composed of LD drive circuits 26 and 29, LDs 25 and 28, collimating lenses 30, 31, an optical coupler 32, an exit window 37a, and a focus lens 37. Here, the LD 25 for measurement emits light of a wavelength to which the sample 3 is not exposed. The light receiving element 6 also has a sensitivity at a wavelength at which the sample 3 is not exposed.

FIG. 7 shows a state in which the present apparatus is constructed using the laser diode unit 27 of FIG. Hereinafter, the operation of the present apparatus will be described. First, the LD 28 is turned on, and the irradiation position on the cantilever 1 is adjusted with the naked eye using visible light emitted from the LD 28. The adjustment of the irradiation position can be performed by moving an irradiation position adjustment stage (similar to the stage 34 in FIG. 4), not shown, attached to the laser diode unit 27. The position of the light receiving element 6 is also adjusted using the X stage 35. After the adjustment is completed in this way,
By turning on the LD 25 and turning off the LD 28 and irradiating a predetermined position on the cantilever 1 with light having a wavelength to which the sample 3 is not exposed, the bending of the beam can be accurately measured by the optical lever method. .

As described above, the present apparatus uses the optical fiber 1
9, the light emitted from the laser diode unit 27 is guided directly to the cantilever 1, so that it is particularly applied to measurement of a low-voltage surface potential or the like where spark discharge or the like does not matter. be able to. Also, LD
25. Since the light-receiving element 6 has a wavelength at which the sample 3 is not exposed to the light emission wavelength and the light-receiving sensitivity, the state of the sample surface is not disturbed by light from the light source, and the measurement accuracy can be improved. When performing alignment using visible light by the LD 28, the LD 2 emitting infrared light is used.
5 may also be turned on at the same time, and after the alignment, only the visible light may be turned off to perform the actual measurement.

FIG. 8 shows an example in which the laser diode unit 27 is applied to a device employing a so-called photothermal method (PT method). This PT
The method is to irradiate the sample 3 with modulated light or pulsed light from a light source that emits a pump beam, and to measure the composition of the substance, nondestructive evaluation of the coating layer, photoacoustic microscope, etc. by the thermoelastic effect caused by this. Say.

Sample 3 is formed of a photosensitive material. Above the sample 3, an LD 38 (semiconductor laser) as a light source for emitting a pump beam and an optical system such as a lens 39 are arranged. This LD 38 is a modulation power supply 4
Driven by 0. An interference filter 41 and a light receiving element 42 (PSD) are disposed obliquely above the sample 3. This light receiving element 42 is connected to an amplifier 43,
This amplifier 43 sends the measurement signal a to the lock-in amplifier 44. A reference signal b is sent from the modulation light source 40 to the lock-in amplifier 44.

The operation of the apparatus employing the PT method will be described. By applying a pump beam from the LD 38 to the surface of the photosensitive sample 3, the sample surface periodically undergoes thermal expansion and causes vertical movement. The vertical movement of the surface of the sample is detected by the optical lever method using the light (probe beam) from the LD 25 of the laser diode unit 27 and the light receiving element 42, and the detected measurement signal a is output to the lock-in amplifier 4
By sending the sample to 4, the surface shape of the sample 3 and the specific heat distribution can be examined. In such a measuring device, the position where the infrared light from the LD 38 is irradiated on the sample surface can be specified using the LD 28 that emits visible light.

Next, another embodiment of the present invention will be described with reference to FIGS. The description of the same parts as those in each of the above-described embodiments is omitted, and the same reference numerals are used for the same parts.

As shown in FIG. 9, on the surface of the cantilever 1 opposite to the surface on which the probe 2 is formed, a wavelength conversion member 45 for converting incident light into visible light is provided. However,
The wavelength conversion member 45 exists in a region other than a region (hereinafter, a probe region A) to which light for detecting bending of the cantilever 1 is irradiated.

FIG. 10 shows an example in which the cantilever 1 having such a wavelength conversion member 45 is formed as a pair with the laser diode unit 27 connected to the optical fiber 19. The laser diode unit 27 includes a laser driving circuit 26, an LD 25, a selfoc collimating lens 24, and an optical fiber coupler 23. A light receiving element 6 is arranged on the reflected light path of the cantilever 1 using the optical lever method. Also in this case, similarly to the above-described fourth embodiment, the LD 25 and the light receiving element 6
The wavelengths to which the sample 3 is not exposed include the emission wavelength and the wavelength of the light receiving sensitivity.

Here, the function of the wavelength conversion member 45 will be described. The infrared light emitted from the LD 25 is emitted from the selfoc lens 20 via the optical fiber 19 and travels toward the cantilever 1. At this time, there is no problem if the infrared light is applied to the probe area A which is a normal measurement position, but the infrared light is applied to an area outside the probe area A, that is, on the wavelength conversion member 45. If so, the infrared light is converted to visible light at the irradiation position and emits light. Since shining in this way means that the infrared light is out of the normal irradiation position, the position of the selfoc lens 20 is searched for the shining position on the wavelength conversion member 45 using a stage (not shown). It is adjusted so as to be guided into the needle area A. As described above, the alignment of the infrared light used for measurement on the cantilever 1 can be simply performed by the naked eye or by using an optical microscope, so that an infrared scope or visible light is emitted. It is not necessary to separately provide the adjustment light source. This makes it possible to provide a small and lightweight device that can be easily positioned.

Next, the material of the wavelength conversion member 45 will be described. The material of the wavelength conversion member 45 is selected according to the emission wavelength of the LD 25 used as a light source. First,
When the LD 25 emits ultraviolet light, in particular, the emission wavelength is 185 n.
In the case of m, 254 nm, the wavelength conversion member 45 is as shown in Table 7,
It is formed by a composition (fluorescent material) as shown in Table 8.

[0054]

[Table 7]

[0055]

[Table 8]

When the LD 25 emits ultraviolet light, particularly when the emission wavelengths are 297 nm, 313 nm, and 365 nm,
When the wavelength is 400 nm or less, the wavelength conversion member 45 is made of a composition (fluorescent material) as shown in Table 9.

[0057]

[Table 9]

When the LD 25 is in the infrared light region, in particular, when the emission wavelength is 800 nm or more, the wavelength conversion member 45 is
0 (fluorescent material).

[0059]

[Table 10]

When the LD 25 is in the infrared light region, in particular, when the emission wavelength is 800 nm or more, the wavelength conversion member 45 is
It consists of a composition (nonlinear optical material) as shown in FIG.

[0061]

[Table 11]

As can be seen from Tables 7 to 11 above,
Efficient light emission can be achieved by appropriately selecting the material of the wavelength conversion member 45 according to the emission wavelength of the LD 25. Note that, in addition to such a material, an organic nonlinear optical material may be used.

Next, still another embodiment of the present invention will be described with reference to FIG. The description of the same parts as those in each of the above-described embodiments is omitted, and the same reference numerals are used for the same parts.

A shielding plate 46 as a shielding member is disposed above the cantilever 1 at regular intervals. A hole 47 is formed in a tip region of the shielding plate 46. The area of the cantilever 1 immediately below the hole 47 is a probe area A to which light for detecting bending of the beam is irradiated. In a region other than the hole 47 on the shielding plate 46, a wavelength conversion member 45 for converting incident light into visible light is provided.

By disposing the shielding plate 46 having the wavelength conversion member 45 above the cantilever 1 as described above,
As in the fifth embodiment described above (see FIG. 10), when infrared light for force detection is irradiated onto the wavelength conversion member 45, the portion becomes visible light and shines. Can be visually adjusted. In addition, since the wavelength conversion member 45 is not formed directly on the cantilever 1 but is formed on a shielding plate 46 that is separately disposed, there are few restrictions on the design and manufacturing of the cantilever 1. The degree of freedom can be increased. In the present embodiment, the shielding member is the shielding plate 46 that covers only the upper part of the cantilever 1;
The present invention is not limited to this, and may cover the entire area of the cantilever 1.

Next, still another embodiment of the present invention will be described with reference to FIGS. The description of the same parts as those in each of the above-described embodiments is omitted, and the same reference numerals are used for the same parts.

The periphery of the cantilever 1 is covered by a shield box 48 as a shielding member. The shield box 48 is made of a conductive material and has a large thickness and high rigidity. Hole 4 at the end of shield box 48
The wavelength conversion member 45 is provided on the upper surface side excluding the hole 47. In addition, shield box 48
The cantilever 1 and the cantilever 1 are connected by a lead wire 49, so that the shield box 48, the cantilever 1 and the probe 2 are set to the same potential.

By providing the wavelength conversion member 45 in this manner, the alignment with the naked eye can be performed so as to be located in the probe area A on the cantilever 1 to which the infrared light for force detection should be originally irradiated. can do. Further, since the shield box 48 is highly rigid, the shield box 48 does not vibrate even when an electrostatic force acts between the shield box 48 and a peripheral device (not shown). Accordingly, the cantilever 1 does not vibrate. Furthermore, since the shield box 48, the cantilever 1 and the probe 2 are set to the same potential, the back surface of the cantilever 1 (the surface opposite to the surface on which the probe 2 is formed) and peripheral devices Since no electrostatic attraction acts between the probe 2 and the probe, the electrostatic attraction acts only between the probe 2 and the sample surface, so that no measurement error occurs. Since the wavelength conversion member 45 is not directly formed on the cantilever 1, the degree of freedom in design and manufacture can be increased.

FIG. 13 shows a modification of FIG. A transparent conductive film 50 made of a transparent conductive material is provided in a region of the hole 47 opened in the shield box 48 so that the upper surface side is closed. This transparent conductive film 50 has the same potential as the shield box 48. By thus closing the probe area A, it is possible to further reduce the electrostatic force acting between the back surface of the cantilever 1 and the peripheral device, thereby further improving the measurement accuracy. Can be.

[0070]

According to the first aspect of the present invention, the light source for measurement and the light receiving element are set so that the wavelength at which the sample is not exposed has the wavelength of the light emission and the light receiving sensitivity. It is possible to enhance the measurement accuracy especially when used as a low-voltage surface potential measurement without being disturbed, and a measurement light source that emits light for force detection and an irradiation position in the light source unit. An adjustment light source that emits visible light for adjustment is provided, so that the position of the light emitted from the measurement light source on the cantilever and the position of incidence on the light receiving element can be easily checked with the naked eye. Matching can be performed.

According to the second aspect of the present invention, since the light source and the light receiving element are formed of a material corresponding to a wavelength to which the sample is not exposed, the state of the sample surface is not disturbed by the light of the light source and the measurement accuracy is improved. Can be further enhanced,
In addition, since the light emitted from the light source is irradiated to the wavelength conversion member on the cantilever and converted into visible light, the irradiation position of the light emitted from the measurement light source can be more easily adjusted. .

According to the third aspect of the present invention, the light source and the light receiving element are set so that the wavelength at which the sample is not exposed has the emission wavelength and the light receiving sensitivity wavelength, so that the state of the sample surface is disturbed by the light from the light source. The measurement accuracy can be further improved, and the light emitted from the light source is radiated to the wavelength conversion member provided on the shielding member to be converted into visible light. The light irradiation position can be adjusted more easily, and the wavelength conversion member is provided not on the cantilever but on the shielding member, which allows freedom in designing and manufacturing the probe and the cantilever. The degree can be increased.

According to the fourth aspect of the present invention, since the light source and the light receiving element are formed of a material corresponding to a wavelength to which the sample is not exposed, the state of the sample surface is not disturbed by the light of the light source and the measurement accuracy is improved. Can be further enhanced,
In addition, since the light emitted from the light source is applied to the wavelength conversion member provided on the shielding member and is converted into visible light, the irradiation position of the light emitted from the measurement light source can be more easily adjusted. In addition, since the wavelength conversion member is provided not on the cantilever but on the shielding member,
The degree of freedom in designing and manufacturing the probe and the cantilever can be increased, and the electrostatic attraction between the cantilever and the peripheral device can be reduced. Errors can be eliminated and measurement accuracy can be increased.

According to a fifth aspect of the present invention, a light-sensitive material of a sample having a photosensitivity of around 400 nm is 600 nm.
Since a light source having the above emission wavelength is used, and a light source having an emission wavelength of 400 nm or less is used for a photosensitive material having a photosensitive sensitivity of around 600 nm, the state of the sample is disturbed by the light from the light source. As a result, the measurement can be performed more accurately.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a physical quantity measurement device according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram illustrating spectral sensitivity of a photoconductor.

FIG. 3 is a configuration diagram showing a light source unit.

FIG. 4 is a configuration diagram illustrating a physical quantity measurement device including the light source unit of FIG. 3;

FIG. 5 is a characteristic diagram showing luminosity in a wavelength region felt by humans.

FIG. 6 is a configuration diagram showing a light source unit.

FIG. 7 is a configuration diagram illustrating a physical quantity measurement device including the light source unit of FIG. 6;

FIG. 8 is a configuration diagram showing a physical quantity measuring device to which a photothermal method is applied.

FIG. 9 illustrates another embodiment of the present invention;
(A) is sectional drawing of a cantilever, (b) is the top view.

FIG. 10 is a configuration diagram illustrating a physical quantity measurement device including the cantilever of FIG. 9;

11 shows still another embodiment of the present invention, wherein (a) is a cross-sectional view of a cantilever, and (b) is a top view thereof. FIG.

12 shows still another embodiment of the present invention, wherein (a) is a cross-sectional view of a cantilever, and (b) is a top view thereof. FIG.

13 shows a modification of FIG. 12, in which (a) is a cross-sectional view of a cantilever, and (b) is a top view thereof.

FIG. 14 is a cross-sectional view showing a basic detection principle by a conventional optical lever method.

15 is a cross-sectional view showing a conventional example to which the detection optical system based on the optical lever method shown in FIG. 14 is applied.

FIG. 16 is a circuit diagram showing a conventional physical quantity measuring device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cantilever (spring) 2 Probe 3 Sample 6 Light receiving element 25 Light source for measurement 28 Light source for adjustment 45 Wavelength conversion members 46, 48 Shielding member

Claims (5)

[Claims] The present invention has a spring to which a probe is attached, and which bends or vibrates or changes in vibration of the spring due to a force acting between the probe and a surface of a sample arranged opposite to the probe. In a physical quantity measurement device that measures the physical quantity of the sample by detecting using a technique, the physical quantity measuring device having a measurement light source that emits light having a wavelength at which the sample is not exposed, and an adjustment light source that emits visible light, A physical quantity measuring device, comprising: a light receiving element having a wavelength at which the light source is irradiated with visible light at the time of measurement and having a wavelength at which the sample is not exposed. 2. A method according to claim 1, wherein the probe has a spring attached thereto, and the spring bends or vibrates due to a force acting between the probe and a surface of the sample disposed opposite to the probe. In a physical quantity measuring device that measures the physical quantity of the sample by detecting using a technique, a light source for measurement that emits light having a wavelength at which the sample is not sensitive, and a light receiving element having sensitivity to a wavelength at which the sample is not sensitive, A physical quantity measuring device provided with a wavelength conversion member for converting light emitted from the measurement light source into visible light, in addition to a portion of the spring on which the light emitted from the measurement light source is irradiated. 3. A spring having a probe attached thereto, wherein the spring bends or vibrates due to a force acting between the probe and a surface of a sample disposed opposite to the probe, and a change in vibration is optically detected. In a physical quantity measuring device for measuring a physical quantity of the sample by detecting using a technique, there is provided a measuring light source for emitting light having a wavelength at which the sample is not sensitive, and a light receiving element having sensitivity to a wavelength at which the sample is not sensitive. A shielding member that covers a part or all of the spring except for a probe region is provided, and a wavelength conversion member that converts light of the measurement light source into visible light is provided on the shielding member. Physical quantity measurement device. 4. A method according to claim 1, wherein the probe has a spring attached thereto, and the spring bends or vibrates due to a force acting between the probe and a surface of the sample arranged opposite thereto. In a physical quantity measuring device for measuring a physical quantity of the sample by detecting using a technique, there is provided a measuring light source for emitting light having a wavelength at which the sample is not sensitive, and a light receiving element having sensitivity to a wavelength at which the sample is not sensitive. A shield member made of a conductive material having a higher rigidity than the spring covering a part or the whole area of the spring except for a probe area of the spring is provided. A physical quantity measuring device comprising: a wavelength conversion member for converting light into visible light; and a shielding member having the wavelength conversion member set to the same potential as the spring and the probe. 5. An emission wavelength of a light source to which a sample is not exposed is set to 4
5. The physical quantity measuring device according to claim 1, wherein the value is not more than 00 nm or not less than 600 nm.