[go: up one dir, main page]

WO2018134984A1 - Balance électronique - Google Patents

Balance électronique Download PDF

Info

Publication number
WO2018134984A1
WO2018134984A1 PCT/JP2017/002028 JP2017002028W WO2018134984A1 WO 2018134984 A1 WO2018134984 A1 WO 2018134984A1 JP 2017002028 W JP2017002028 W JP 2017002028W WO 2018134984 A1 WO2018134984 A1 WO 2018134984A1
Authority
WO
WIPO (PCT)
Prior art keywords
light
displacement
photodiode
unit
slit
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2017/002028
Other languages
English (en)
Japanese (ja)
Inventor
耕介 藤田
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shimadzu Corp
Original Assignee
Shimadzu Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Shimadzu Corp filed Critical Shimadzu Corp
Priority to JP2018562839A priority Critical patent/JPWO2018134984A1/ja
Priority to PCT/JP2017/002028 priority patent/WO2018134984A1/fr
Publication of WO2018134984A1 publication Critical patent/WO2018134984A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01G—WEIGHING
    • G01G7/00—Weighing apparatus wherein the balancing is effected by magnetic, electromagnetic, or electrostatic action, or by means not provided for in the preceding groups
    • G01G7/02—Weighing apparatus wherein the balancing is effected by magnetic, electromagnetic, or electrostatic action, or by means not provided for in the preceding groups by electromagnetic action
    • G01G7/04—Weighing apparatus wherein the balancing is effected by magnetic, electromagnetic, or electrostatic action, or by means not provided for in the preceding groups by electromagnetic action with means for regulating the current to solenoids

Definitions

  • the present invention relates to an electronic balance in which light from a light emitting diode is received by a photodiode and the mass of an object to be measured is calculated based on the amount of received light.
  • the electronic balance is placed on the opposite side of the weighing pan with the fulcrum between the weighing pan on which the measurement object is placed, and the displacement part that is displaced by the gravity of the measurement object and the displacement amount of the displacement part are detected. And a detecting unit for performing the operation.
  • an external force is applied so that the displacement of the displacement portion becomes zero, and the mass of the measurement object is calculated according to the value of the external force (for example, see Patent Document 1 below).
  • the electronic balance includes an electromagnetic force generator having a coil and a magnetic circuit, and a control unit.
  • the detection unit includes a light emitting diode and a photodiode that receives light from the light emitting diode.
  • the amount of light received by the photodiode changes according to the displacement of the displacement portion.
  • the electromagnetic force generator an electric current is passed through a coil to generate an electromagnetic force, and the electromagnetic force is applied to the displacement portion.
  • the control unit changes the value of the current passed through the coil based on the amount of light received by the photodiode so that the displacement of the displacement unit becomes zero.
  • the mass of the measurement object is calculated based on the current value.
  • the present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electronic balance capable of improving measurement accuracy without causing structural problems.
  • the electronic balance according to the present invention includes a weighing pan, a displacement unit, an external force application unit, a detection unit, a control unit, and a calculation unit.
  • An object to be measured is placed on the weighing pan.
  • the displacement part is provided so as to be swingable with respect to a fulcrum, and is formed to swing in a certain direction due to the gravity of the measurement object placed on the weighing pan, and to form a slit extending in the certain direction.
  • the external force applying unit applies a force that swings the displacement unit in the reverse direction to the displacement unit that swings due to the gravity of the measurement target.
  • the detection unit includes a light emitting diode and a photodiode provided with the slit interposed therebetween.
  • the control unit controls the force applied by the external force applying unit to the displacement unit based on the amount of light received by the photodiode from the light emitting diode through the slit.
  • the calculation unit calculates a value corresponding to the force applied by the external force applying unit to the displacement unit as the mass of the measurement object.
  • the photodiode has two light receiving surfaces arranged with a gap in the fixed direction, and the gap is disposed in a region facing the light emitting diode in the optical axis direction.
  • the width of the slit in the certain direction is 0.4 mm or less.
  • light with high directivity is emitted from the light emitting diode.
  • the light from the light-emitting diode passes through a narrow slit having a width of 0.4 mm or less and is received by the photodiode.
  • the control unit controls the force applied by the external force applying unit to the displacement unit based on the amount of light received by the photodiode, and the calculation unit calculates a value corresponding to the force of the external force applying unit. Calculated as mass. Therefore, the influence of noise on the calculated mass can be reduced.
  • two light receiving surfaces with respect to a unit light reception amount of a photodiode are obtained by irradiating light with high directivity from the light emitting diode and passing the light through a narrow slit having a width of 0.4 mm or less.
  • the measurement accuracy can be improved by increasing the value of the difference between the received light amounts at the two light receiving surfaces with respect to the unit received light amount at the photodiode. As a result, it is possible to improve the measurement accuracy without causing structural problems.
  • FIG. 3 is a side sectional view taken along line AA in FIG. 2. It is the block diagram which showed the specific structure of the control part and its peripheral member. It is the graph which showed the relationship between the mechanical sensitivity in an electronic balance, and the slit width of a shutter.
  • the electronic balance 1 includes a beam 2, a fulcrum 3, a weighing pan 4, a displacement unit 5, a detection unit 6, and an external force application unit 7.
  • the beam 2 is formed in an elongated shape and extends in the horizontal direction.
  • the fulcrum 3 supports the central portion of the beam 2.
  • the beam 2 can swing around the fulcrum 3.
  • the weighing pan 4 is provided at one end of the beam 2.
  • a sample S that is a measurement object is placed on the weighing pan 4.
  • the displacement part 5 is provided at the other end of the beam 2.
  • the displacement part 5 swings integrally with the beam 2.
  • the detection unit 6 detects a displacement caused by the swinging of the displacement unit 5. The detailed configurations of the detection unit 6 and the displacement unit 5 will be described later.
  • the external force portion imparting portion 7 is provided in the vicinity of the other end portion of the beam 2.
  • the external force imparting portion 7 is a member (mechanism) that imparts an external force to the displacement portion 5 via the beam 2.
  • the external force applying unit 7 includes a coil 8 and a permanent magnet 9.
  • the coil 8 is fixed to the vicinity of the other end of the beam 2. Therefore, the coil 8 is displaced integrally with the beam 2.
  • the coil 8 is supplied with a current whose size is appropriately changed.
  • the permanent magnet 9 is arranged at a distance from the coil 8.
  • the permanent magnet 9 is fixed separately from the beam 2 (coil 8).
  • the permanent magnet 9 forms a static magnetic field, and the coil 8 is disposed in the static magnetic field.
  • the detection unit 6 detects the displacement of the displacement unit 5 due to the swing of the beam 2.
  • an electromagnetic force is generated by passing a current through the coil 8.
  • the magnitude of the electromagnetic force is determined by the value of the current flowing through the coil 8.
  • a force is applied to the coil 8 in a direction away from the permanent magnet 9, and a force directed downward (opposite to the displacement direction) is applied to the displacement portion 5 via the beam 2.
  • FIG. 2 is an enlarged side view showing the displacement unit 5 of the electronic balance 1.
  • FIG. 3 is a side sectional view taken along line AA in FIG. For convenience, FIG. 2 does not show the detection unit 6.
  • the electronic balance 1 includes the displacement unit 5 and the detection unit 6.
  • the displacement part 5 is a plate-shaped member (shutter) having a rectangular shape in a side view. As described above, the displacement portion 5 can swing in the vertical direction, and the swinging direction is orthogonal to the thickness direction. A slit 51 is formed in the displacement portion 5.
  • the slit 51 is disposed at the center in the vertical direction in the displacement portion 5 and penetrates the displacement portion 5 in the thickness direction.
  • the slit 51 extends along the vertical direction and the horizontal direction.
  • the width D1 of the slit 51 in the vertical direction (swing direction) that is, from the upper end edge (one end edge in the swing direction) of the slit 51 to the lower end edge (the other end edge in the swing direction) of the slit 51.
  • the width D1 is 0.4 mm or less.
  • the detection unit 6 includes a light emitting diode 61 and a photodiode 62.
  • the light emitting diode 61 is disposed with a distance from the displacement portion 5. Specifically, the light emitting diodes 61 are arranged with a gap in the horizontal direction with respect to the slits 51 of the displacement portion 5. The optical axis direction of the light emitted from the light emitting diode 61 is along the horizontal direction.
  • the photodiode 62 is disposed on the opposite side of the light emitting diode 61 with the displacement portion 5 (slit 51) interposed therebetween. That is, the photodiode 62 and the light emitting diode 61 are provided with the displacement portion 5 (slit 51) interposed therebetween.
  • the photodiode 62 is a two-divided photodiode formed in a plate shape, and includes a first light receiving surface 621 and a second light receiving surface 622.
  • the first light receiving surface 621 is arranged on the upper side of the photodiode 62 and faces the displacement portion 5.
  • the first light receiving surface 621 is formed in a rectangular shape in side view.
  • a light emitting element is mounted on the first light receiving surface 621.
  • the second light receiving surface 622 is disposed on the lower side of the photodiode 62 and faces the displacement portion 5.
  • the second light receiving surface 622 is disposed below the first light receiving surface 621 with a space therebetween.
  • the second light receiving surface 622 is formed in a rectangular shape in side view.
  • a light emitting element is mounted on the second light receiving surface 622.
  • the width D2 of the gap 623 between the first light receiving surface 621 and the second light receiving surface 622 in the vertical direction is a displacement portion. It is smaller than the width D1 of the five slits 51.
  • the width D2 of the gap 623 between the first light receiving surface 621 and the second light receiving surface 622 is, for example, 0.03 mm.
  • a gap 623 between the first light receiving surface 621 and the second light receiving surface 622 is disposed in a region facing the light emitting diode 61 in the optical axis direction.
  • the center of the gap 623 between the first light receiving surface 621 and the second light receiving surface 622 and the center of the slit 51 of the displacement portion 5 are the light from the light emitting diode 61. Located on the optical axis.
  • the light source B of the light emitting diode 61 emits light with high directivity. Light from the light source B is refracted in the process of passing through the outer surface of the light emitting diode 61 and travels toward the displacement portion 5. A part of the light from the light emitting diode 61 passes through the slit 51 of the displacement portion 5 and travels toward the photodiode 62. At this time, if there is no refraction of the light, the light can be captured in the same manner as it is emitted from the virtual point light source C.
  • the virtual point light source C is an apparent light source when it is assumed that there is no light refraction, and is an imaginary light source.
  • the virtual point light source C is located at a point farther from the displacement unit 5 and the photodiode 62 than the light source B.
  • the angle ⁇ formed by the vertical end edges of the slit 51 of the displacement portion 5 with respect to the virtual point light source C is between the first light receiving surface 621 and the second light receiving surface 622 with respect to the virtual point light source C. It is larger than the angle ⁇ 0 formed by both end edges of the gap 623.
  • the angle ⁇ is a line segment connecting the virtual point light source C and the upper edge of the slit 51 of the displacement part 5 and a line segment connecting the virtual point light source C and the lower edge of the slit 51 of the displacement part 5 in a side view. It is an angle to make.
  • the angle ⁇ 0 is a line segment connecting the virtual point light source C and the lower end edge of the first light receiving surface 621 and a line segment connecting the virtual point light source C and the upper end edge of the second light receiving surface 622 in the side view. Is an angle.
  • FIG. 4 is a block diagram showing a specific configuration of the control unit 20 and its peripheral members.
  • the electronic balance 1 includes a display 10 and a control unit 20 in addition to the coil 8, the light emitting diode 61, and the photodiode 62 described above.
  • the display device 10 includes, for example, a liquid crystal display screen. The display 10 displays the mass of the measurement object.
  • the control unit 20 includes, for example, a CPU (Central Processing Unit).
  • the control unit 20 controls each operation of the coil 8, the display 10, and the light emitting diode 61 based on the detection signal from the photodiode 62.
  • the control unit 20 functions as a current control unit 201, a calculation unit 202, a light amount control unit 203, and the like when the CPU executes a program.
  • the current control unit 201 determines the value of the current flowing through the coil 8 based on the detection signal from the photodiode 62.
  • the coil 8 is supplied with the current determined by the current control unit 201.
  • the magnitude of the electromagnetic force in the external force applying unit 7 is determined based on the value of the current flowing through the coil 8. That is, the current control unit 201 performs control to determine the magnitude of the electromagnetic force in the external force applying unit 7 based on the amount of light received by the photodiode 62.
  • the calculation unit 202 performs a process of calculating the mass of the measurement object based on the value of the current passed through the coil 8 determined by the current control unit 201 and causing the display unit 10 to display the calculated mass value.
  • the light quantity control unit 203 determines the light emission amount of the light emitting diode 61 based on the detection signal from the photodiode 62 so that the total amount of light received by the photodiode 62 is kept constant.
  • the light emitting diode 61 emits light with the light emission amount determined by the light amount control unit 203.
  • Control Unit As shown in FIG. 3, when light is emitted from the light source B of the light emitting diode 61, a part of the light passes through the slit 51 of the displacement unit 5 toward the photodiode 62. In the photodiode 62, light that has passed through the slit 51 of the displacement portion 5 is received by the first light receiving surface 621 and the second light receiving surface 622.
  • the amount of light received by the first light receiving surface 621 and the amount of light received by the second light receiving surface 622 are the same. If the displacement unit 5 is displaced upward due to the gravity of the measurement object (sample S) placed on the weighing pan 4, the amount of light received by the first light receiving surface 621 increases, and the second light receiving surface 622 The amount of light received decreases. On the other hand, if the displacement part 5 is displaced downward, the amount of light received by the first light receiving surface 621 decreases and the amount of light received by the second light receiving surface 622 increases.
  • the light amount control unit 203 determines the light emission amount of the light emitting diode 61 so that the total amount of light received by the photodiode 62 is kept constant.
  • the current control unit 201 calculates the difference between the amount of light received by the first light receiving surface 621 and the amount of received light by the second light receiving surface 622 based on the detection signal from the photodiode 62. . Then, the current control unit 201 performs feedback control for determining the value of the current flowing through the coil 8 so that the calculated difference in received light amount becomes zero. Specifically, the current control unit 201 divides the difference (difference received light amount) between the amount of light received by the first light receiving surface 621 and the amount of received light by the second light receiving surface 622 by the total amount of received light by the photodiode 62. Feedback control is performed to determine the value of the current that flows through the coil 8 so that the value (the value of the difference light reception amount with respect to the unit light reception amount at the photodiode 62) becomes zero. The coil 8 is supplied with the determined current.
  • the calculation unit 202 calculates the mass of the measurement object (sample S) based on the current value determined by the current control unit 201 and causes the display unit 10 to display the calculated mass value.
  • I represents the energy of the light emitting diode 61.
  • I 0 indicates the energy of light emitted perpendicularly (angle 0 °) from the light emitting diode 61
  • I ( ⁇ ) indicates the energy at the angle ⁇ from the light emitting diode 61
  • ⁇ 0 is The angle at which the light quantity of the light emitting diode 61 is 1 / e is shown.
  • I (Z) represents the incident energy per unit area at an angle ⁇ from the virtual point light source C in the displacement portion 5.
  • P + represents the incident energy at the first light receiving surface 621 of the photodiode 62.
  • P ⁇ indicates the incident energy at the second light receiving surface 622 of the photodiode 62.
  • P ⁇ indicates the incident energy at the first light receiving surface 621 of the photodiode 62 or the incident energy at the second light receiving surface 622 of the photodiode 62.
  • P indicates the energy difference between the incident energy at the first light receiving surface 621 of the photodiode 62 and the incident energy at the second light receiving surface 622 of the photodiode 62.
  • Equation (4) is a value obtained by dividing the difference between the amount of received light at the first light receiving surface 621 and the amount of received light at the second light receiving surface 622 (difference received light amount) by the total amount of received light at the photodiode 62 (photo This corresponds to the value of the difference received light amount relative to the unit received light amount at the diode 62). Further, when the formula (4) is differentiated by ⁇ , the following formula (5) is obtained.
  • This equation (10) shows the change in the signal intensity of the photodiode 62 with respect to the unit displacement amount of the displacement portion 5, and shows the mechanical sensitivity of the electronic balance 1.
  • FIG. 5 is a graph showing the relationship between the mechanical sensitivity of the electronic balance 1 and the width D1 of the slit 51 of the displacement portion 5.
  • the vertical axis indicates the mechanical sensitivity of the electronic balance 1
  • the horizontal axis indicates the width D ⁇ b> 1 of the slit 51 of the displacement portion 5.
  • the slit 51 of the displacement part 5 is formed so that the width D1 in the vertical direction (swinging direction) is 0.4 mm or less. Further, light with high directivity is emitted from the light emitting diode 61. Then, the light from the light emitting diode 61 passes through the narrow slit 51 having a width of 0.4 mm or less, and is received by the photodiode 62.
  • the current control unit 201 determines the value of the current passed through the coil 8 so that the value (the difference between the received light amounts at the two light receiving surfaces with respect to the unit received light amount at the photodiode 62) becomes zero. .
  • the coil 8 is supplied with the determined current.
  • the calculation unit 202 calculates the mass of the measurement object based on the current value determined by the current control unit 201. Therefore, the influence of noise on the calculated mass can be reduced, and as a result, the calculation accuracy of the mass of the measurement object by the calculation unit 202 can be improved.
  • the electronic balance 1 by setting the width D1 of the slit 51 of the displacement portion 5 to 0.4 mm or less, the value of the difference in the amount of light received at the two light receiving surfaces with respect to the unit amount of light received by the photodiode 62 (The change in the signal intensity of the photodiode 62 with respect to the unit displacement amount of the displacement unit 5 can be increased to reduce the influence of noise, and the measurement accuracy can be improved. Therefore, it is possible to improve the measurement accuracy without causing structural problems.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Length Measuring Devices By Optical Means (AREA)

Abstract

L'invention concerne une balance électronique (1) comprenant une partie déplacement (5) et une partie détection (6). Une fente (51) est formée dans la partie déplacement (5) et une diode électroluminescente (61) et une photodiode (62) sont comprises dans la partie détection (6). La fente (51) dans la partie déplacement (5) est formée de telle sorte qu'une largeur D1 dans la direction verticale (direction de balancement) ne soit pas supérieure à 0,4 mm. En outre, une lumière présentant une directivité élevée est émise à partir de la diode électroluminescente (61). De plus, la lumière provenant de la diode électroluminescente (61) passe à travers la fente (51) présentant une largeur étroite ne dépassant pas 0,4 mm et est reçue par la photodiode (62). Par conséquent, la précision de mesure peut être améliorée par l'agrandissement d'un changement d'intensité de signal de la photodiode (62) par rapport à la quantité de déplacement unitaire de la partie déplacement (5). Ainsi, la précision de mesure peut être améliorée sans provoquer de défaillance de configuration.
PCT/JP2017/002028 2017-01-20 2017-01-20 Balance électronique Ceased WO2018134984A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP2018562839A JPWO2018134984A1 (ja) 2017-01-20 2017-01-20 電子天秤
PCT/JP2017/002028 WO2018134984A1 (fr) 2017-01-20 2017-01-20 Balance électronique

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/JP2017/002028 WO2018134984A1 (fr) 2017-01-20 2017-01-20 Balance électronique

Publications (1)

Publication Number Publication Date
WO2018134984A1 true WO2018134984A1 (fr) 2018-07-26

Family

ID=62908636

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2017/002028 Ceased WO2018134984A1 (fr) 2017-01-20 2017-01-20 Balance électronique

Country Status (2)

Country Link
JP (1) JPWO2018134984A1 (fr)
WO (1) WO2018134984A1 (fr)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013181979A (ja) * 2012-02-29 2013-09-12 Mettler-Toledo Ag 光電子位置検知器を用いる磁力補償の原理に基づく計量セル

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013181979A (ja) * 2012-02-29 2013-09-12 Mettler-Toledo Ag 光電子位置検知器を用いる磁力補償の原理に基づく計量セル

Also Published As

Publication number Publication date
JPWO2018134984A1 (ja) 2019-11-07

Similar Documents

Publication Publication Date Title
US9958344B2 (en) Force-transmitting mechanism with a separate lever arm extending to a position sensor
JP5736822B2 (ja) 伸び測定システムおよび方法
JP2004286598A (ja) 変位計および変位測定方法
KR20140107244A (ko) 플렉시블 광학 측정용 지그
CN107015236B (zh) 光电传感器
JP5502963B2 (ja) 変位計測装置及び変位計測方法
WO2018134984A1 (fr) Balance électronique
JPH07113617A (ja) 変位計及び変位測定方法、厚み計
CN101799281B (zh) 辊平行检测系统
US10900987B2 (en) Robust particle velocity measurement
JP6569112B1 (ja) 流量検出装置及び流量検出方法
JP6794046B2 (ja) 電磁平衡式重量センサ
JP5568997B2 (ja) 電子天秤
JP5734484B2 (ja) 変位計測装置及び変位計測方法
US11067490B2 (en) Bracket, support system, and thrombelastography device and use method thereof
JP2014025756A (ja) 位置検出装置
KR101450050B1 (ko) 마이크로 힘 발생 및 측정장치 및 그 방법
JP2014174010A (ja) 厚さ測定装置
JP2014163826A (ja) 位置検出器
JP6794045B2 (ja) 電磁平衡式重量センサ
JP2003097911A (ja) 変位測定装置およびそれを用いた変位測定方法
US10571322B2 (en) Measuring a spatiotemporal relationship between two of more positions of a vibratory element
JP2025075152A (ja) 水準器
JP6794047B2 (ja) 電磁平衡式重量センサ
JP2012173203A (ja) 光束の位置変化検出装置

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 17892918

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2018562839

Country of ref document: JP

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 17892918

Country of ref document: EP

Kind code of ref document: A1