electronic balance

Abstract

The present invention provides an electronic balance (1), comprising: a non-contact sensor (30) having a substrate (31), a directional light-emitting element (32) fixed to the surface of the substrate (31) in a manner pointing to a target detection space, and a directional light-receiving element (33) fixed to the surface of the substrate (31) in a manner separated from the light-emitting element (32) and pointing to the target detection space; and an action control unit (50) for controlling the action of a specified part of the electronic balance (1) according to a detection signal of the non-contact sensor (30).

Description

Technical Field

[0001] The invention relates to an electronic balance. Background Art

[0002] In laboratories and other environments, electronic balances are used to measure the mass (weight) of objects such as powders. These electronic balances include a windshield surrounding the weighing pan to prevent the effects of convection and other factors in the measurement environment. The windshield is equipped with an openable / closable door. To measure the object, the windshield door is opened, the object is placed on the weighing pan, the door is closed, and the weight displayed on the balance is checked to obtain the object's weight.

[0003] Previously, users manually opened and closed the door of the windshield, but in recent years, electronic balances that can automatically open and close the door of the windshield have become popular. Although there are cases where the user presses a physical switch to automatically open and close the door, the electronic balances described in Patent Document 1 and Non-Patent Document 1 use a non-contact sensor to open and close the door. In the electronic balance, when the user extends his hand to the non-contact sensor with the door closed, the drive motor runs and the door opens, and when the user extends his hand to the non-contact sensor with the door open, the drive motor runs and the door closes. By using this non-contact sensor, the user can operate it simply by bringing his hand close to the non-contact sensor, and therefore, there is no need to put down the reagent bottle or medicine spoon every time the door is opened and closed.

[0004] The electronic balance described in Non-Patent Document 1 uses a reflective non-contact sensor. Specifically, it uses an integrated sensor device consisting of a light-emitting element (LED) and a light-receiving element (PD). When a user places their hand or other device near the sensor device in a non-contact manner, light with a specific wavelength generated by the light-emitting element is reflected or scattered by the hand or other device. The reflected or scattered light of the specific wavelength is detected by the light-receiving element, thereby detecting the presence of the hand or other device near the sensor device.

[0005] Here, if the light emitted by the light-emitting element spreads over a wider range than necessary, or if the light-receiving element receives light from a wider range than necessary, the light-receiving element may detect reflected or scattered light even when the user's hand, for example, is positioned to the side of the sensor device, potentially causing the windshield door to open or close despite the user's unintentional action. Therefore, in the electronic balance described in Non-Patent Document 1, the light-emitting element is arranged axially spaced (inward) from the opening within a cylindrical light-emitting element housing with an opening at one end. Similarly, the light-receiving element is arranged axially spaced (inward) from the opening within the cylindrical light-receiving element housing. These light-emitting and light-receiving element housings are then tilted and fixed so that their axes intersect within the target detection space. By positioning the light-emitting element further inward than the opening of the light-receiving element housing, the diffusion of emitted light is suppressed, and by positioning the light-receiving element further inward than the opening of the light-receiving element housing, the range of light incident on the light-receiving element is limited. This prevents the sensor device from detecting the user's hand, etc., over a wider range than necessary, thereby preventing the user from accidentally opening or closing the windshield door. However, if the light-emitting direction of the light-emitting element is to be aligned with the opening direction of the light-emitting element receiving portion, the light-emitting element receiving portion must be used to secure the light-emitting element. This leads to the problem of increasing the size of the light-emitting element receiving portion to sufficiently secure the light-emitting element.

[0006] [Prior art literature]

[0007] [Patent Document]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2019-194575

[0009] [Non-patent literature]

[0010] [Non-Patent Document 1] “Reference Manual Analytical Balances and Comparators XPR,” [Online], publication date unknown, Mettler-Toledo GmbH, [retrieved on August 11, 2021], Internet <https: / / www.mt.com / dam / P5 / labtec / 02_Analytical_Balances / 10_Excellence_Line / RM_XPR_Analytical_and_Comparators_JA.pdf> Summary of the Invention

[0011] [Problems to be solved by the invention]

[0012] In many electronic balances, to improve the analyst's operability, a flat-plate operation panel unit is positioned in front of the weighing pan and windshield, so that the bottom of the weighing pan is not obscured from view by the user. The operation panel unit houses a display device that displays the measured weight, etc., as well as switches for performing operations such as switching the displayed content. The non-contact sensor for opening / closing the door is ideally located within the operation panel unit, since its detection space is preferably located above (or in front of) the operation panel unit. However, the electronic balance described in Non-Patent Document 1 requires the vertical arrangement of a cylindrical light-emitting element housing and a light-receiving element housing. Consequently, the non-contact sensor requires a predetermined height, and the thickness of the operation panel unit that houses it also increases.

[0013] The problem to be solved by the present invention is to provide an electronic balance that can reduce the space required for installing a non-contact sensor.

[0014] [Technical means to solve the problem]

[0015] The electronic balance of the present invention, which is designed to solve the above-mentioned problems, includes:

[0016] A non-contact sensor comprising a substrate, a directional light emitting element fixed to a surface of the substrate so as to point toward a target detection space, and a directional light receiving element fixed to the surface of the substrate so as to be separated from the light emitting element and point toward the target detection space; and

[0017] The operation control unit controls the operation of a predetermined portion of the electronic balance based on the detection signal of the non-contact sensor.

[0018] In the electronic balance of the present invention, by using a directional light-emitting element and a similarly directional light-receiving element, there is no need for a cylindrical member to limit the light-emitting or light-receiving range. This reduces the height of the non-contact sensor. Consequently, the operation panel unit located in front of and below the weighing pan and windshield can accommodate the non-contact sensor without increasing its thickness.

[0019] [Effects of the Invention]

[0020] According to the electronic balance of the present invention, the space required for arranging the non-contact sensor can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a perspective view showing one embodiment of the electronic balance of the present invention.

[0022] Figure 2 It is a top view showing the electronic balance according to this embodiment.

[0023] Figure 3 It is an exploded perspective view of the non-contact sensor included in the electronic balance according to this embodiment.

[0024] Figure 4 It is a cross-sectional view of the non-contact sensor included in the electronic balance according to this embodiment.

[0025] Figure 5 It is a cross-sectional view showing a state during the operation of fixing the light emitting element to the substrate.

[0026] Figure 6 This is a cross-sectional view showing a state where the non-contact sensor is fixed within the housing of the operation panel unit.

[0027] [Explanation of Symbols]

[0028] 1: Electronic balance

[0029] 10: Main body

[0030] 101: Base

[0031] 102: Posterior wall

[0032] 11: Weighing pan

[0033] 12: Operation panel unit

[0034] 121: Lower frame wall

[0035] 122: Upper frame wall

[0036] 123: Infrared rays pass through the window

[0037] 13: Static Eliminator

[0038] 14: Power switch

[0039] 20: Windshield

[0040] 21: Frame

[0041] 22: Anterior side wall

[0042] 23: Rear sidewall

[0043] 24: Right door

[0044] 25: Left door

[0045] 26: Upper side door

[0046] 27: Handle

[0047] 30: Non-contact sensor

[0048] 301: Right non-contact sensor

[0049] 302: Left non-contact sensor

[0050] 31: Substrate

[0051] 311: Hole provided on the substrate

[0052] 32: Light-emitting element

[0053] 321: Axis of maximum luminous intensity

[0054] 322: Bottom surface of light emitting element

[0055] 323: Solder

[0056] 33: Light receiving element

[0057] 331: Axis of maximum light receiving intensity

[0058] 34: Visible light source

[0059] 35: Component cover

[0060] 351: Protrusion

[0061] 352: Luminous side light passes through the hole

[0062] 353: Light receiving side light passing hole

[0063] 354: Visible light passes through the hole

[0064] 36: protrusion embedded hole

[0065] 37: Baseboard fixing parts

[0066] 371: Frame contact portion

[0067] 3711: Hole provided at the frame contact portion

[0068] 372: Central erection department

[0069] 373: Left vertical setting part

[0070] 374: Right vertical setting part

[0071] 375: Left protrusion

[0072] 376: Right protrusion

[0073] 381: Left embedded hole

[0074] 382: Right embedded hole

[0075] 391: Bolt

[0076] 40: Input display unit

[0077] 41: Display area

[0078] 42: Operation area

[0079] 50: Motion Control Unit

[0080] 90: Fixture

[0081] 91: Bottom surface of the fixture

[0082] 92: Inclined surface of the fixture DETAILED DESCRIPTION

[0083] use Figures 1 to 6 , to illustrate the embodiment of the electronic balance of the present invention. Figure 1 As shown, the electronic balance 1 of this embodiment includes an electronic balance body 10 having a base 101 and a rear wall 102, a weighing pan 11 disposed on the upper surface of the base 101 and on which an object to be measured is placed, an operation panel unit 12, and a windshield 20 surrounding the weighing pan 11. The space enclosed by the windshield 20 constitutes a weighing chamber. The weight of the object to be measured placed on the weighing pan 11 is measured by a weighing mechanism (not shown) disposed within the base 101.

[0084] The windshield 20 includes a front sidewall 22, a rear sidewall 23, a frame 21 that supports the front sidewall 22 and connects the two sides at their upper ends, and a right door 24, a left door 25, and an upper door 26, all supported by the frame 21 so as to be openable and closable. The front sidewall 22, the right door 24, the left door 25, and the upper door 26 are made of a transparent material such as glass. These right door 24, the left door 25, and the upper door 26 are automatically opened and closed by a door opening / closing mechanism (not shown) driven by a drive motor located within the rear wall 102, each of which is operated by a user (described later). Furthermore, each door is provided with a handle 27, which the user can use to manually open and close. An ionizer 13 is provided on the rear sidewall 23 to remove static electricity from the weighing chamber.

[0085] The operation panel unit 12 is located in front of the windshield 20 and below the weighing pan 11 so as not to obscure the user's view. The operation panel unit 12 includes a power switch 14, an input display (operation panel) 40, and two non-contact sensors: a right non-contact sensor 301 and a left non-contact sensor 302. The input display 40 is a combination of a liquid crystal panel and a touchpad. It includes a display area 41 for displaying weighing values ​​or setting items, and an operation area 42 for displaying images representing operation keys and buttons. Furthermore, the operation panel unit 12 houses an action control unit 50, which controls the opening and closing of the right door 24, the left door 25, and the upper door 26 based on detection signals from the right non-contact sensor 301 and the left non-contact sensor 302. The action control unit 50 is implemented by combining hardware such as a central processing unit (CPU) with software that operates the hardware.

[0086] The right non-contact sensor 301 is arranged on the right side of the input display unit 40, and the left non-contact sensor 302 is arranged on the left side of the input display unit 40. Figure 2 As shown by the dotted line in the middle, when an object such as a hand approaches, the object is detected in a non-contact manner. Right non-contact sensor 301 and left non-contact sensor 302 have the same structure. Hereinafter, right non-contact sensor 301 and left non-contact sensor 302 will be collectively referred to as "non-contact sensor 30."

[0087] like Figure 3 A three-dimensional diagram (shown as a three-part diagram for easier understanding) and Figure 4 As shown in the cross-sectional view of FIG, the contactless sensor 30 includes a substrate 31, and a light-emitting element 32 and a light-receiving element 33, each separately fixed to the surface of the substrate 31 (other components of the contactless sensor 30 will be described later). The light-emitting element 32 emits infrared light in a predetermined wavelength band, and the light-receiving element 33 detects infrared light in that wavelength band.

[0088] An LED package is used in the light-emitting element 32. This LED package is formed by sealing the LED with a lens-like sealing resin. Since the sealing resin is lens-like in shape, the light generated by the LED and radiated to the outside of the LED package through the sealing resin has directivity. A PD is used in the light-receiving element 33 to detect this directional light. These LED packages and PDs are manufactured by multiple manufacturers (the number varies depending on the manufacturer), and each manufacturer generally discloses data related to the directivity of these LED packages or PDs. By referring to this data, for example, an LED package (PD) can be selected whose luminous (light-receiving) intensity, when tilted 60° toward the angle at which the self-luminous (light-receiving) intensity reaches its maximum value, is less than half of the maximum value. This angle is preferably 45° or less, and more preferably 30° or less.

[0089] These light emitting elements 32 and light receiving elements 33 are fixed to the substrate 31 in a manner that they point to the target detection space. Specifically, the orientation of the two elements is set to be: an axis extending along the direction in which the light intensity of the light emitting element 32 is the largest (refer to Figure 4 . Referred to as "maximum luminous intensity axis 321"), and an axis extending in the direction in which the light receiving intensity of the light receiving element 33 is maximum (refer to Figure 4 . It is called the “light receiving intensity maximum axis 331”) and crosses above the substrate 31 (in the case of the right non-contact sensor 301, it is the space above the right side of the operation panel unit 12, and in the case of the left non-contact sensor 302, it is the space above the left side of the operation panel unit 12).

[0090] The light-emitting element 32 is oriented in the above manner, with its rectangular bottom surface 322, which is perpendicular to the axis 321 of maximum luminous intensity, tilted relative to the surface of the substrate 31. The light-emitting element 32 is fixed to the surface of the substrate 31 at two points near the ends of one side of the rectangle by solder 323. A hole 311 is provided on the surface of the substrate 31 between the two points where the solder 323 is attached to fix the light-emitting element 32. The hole 311 is used to prevent a portion of the bottom surface of the light-emitting element 32 from interfering with the surface of the substrate 31 when the light-emitting element 32 is tilted relative to the surface of the substrate 31. When manufacturing the electronic balance of this embodiment, as shown in FIG. Figure 5 As shown, a fixture 90 having an inclined surface 92 formed at the same inclination angle relative to the bottom surface 91 as the angle at which the light-emitting element 32 is inclined is placed on the surface of the substrate 31, and then welding is performed in a state where the bottom surface 322 of the light-emitting element 32 is in contact with the inclined surface 92 of the fixture 90.

[0091] Meanwhile, the light receiving element 33 is fixed to the surface of the substrate 31 so that its entire bottom surface, perpendicular to the axis 331 of maximum light receiving intensity, is in close contact with the surface. Alternatively, the bottom surface of the light receiving element 33 can be fixed at an angle relative to the surface of the substrate 31, either together with the light emitting element 32 or in place of the light emitting element 32. This tilted fixing of the light receiving element 33 relative to the substrate 31 eliminates the need for the element cover 35 used in conventional techniques to secure the light receiving element 33, thereby reducing the size of the element cover 35.

[0092] A visible light source 34 is also provided on the surface of the substrate 31. The visible light source 34 is provided to indicate the operation of the non-contact sensor 30 by lighting it. Furthermore, to prevent the door from opening or closing due to a user accidentally placing their hand near the non-contact sensor 30, for example, the user can perform a predetermined operation using the operation keys of the input display unit 40 to deactivate only the non-contact sensor 30 while the electronic balance 1 is operating. In this case, the visible light source 34 turns off, indicating that the non-contact sensor 30 is deactivated.

[0093] An element cover 35 is provided above the substrate 31 and the elements fixed to the substrate 31. A protrusion 351 is provided on the lower surface of the element cover 35, and a protrusion insertion hole 36 is provided on the substrate 31 corresponding to the protrusion 351. The element cover 35 is attached to the substrate 31 by inserting the protrusion 351 into the protrusion insertion hole 36. Furthermore, the element cover 35 has formed therein: a light-emitting-side light-transmitting hole 352, located above the light-emitting element 32, aligned with the axis of maximum light-emitting intensity 321 and tilted relative to the substrate 31; a light-receiving-side light-transmitting hole 353, located above the light-receiving element 33, aligned with the axis of maximum light-receiving intensity 331 and perpendicular to the substrate 31; and a visible light-transmitting hole 354, located above the visible light source 34 and perpendicular to the substrate 31. Element cover 35 is made of a material that suppresses diffuse reflection of infrared light in the wavelength band emitted by light-emitting element 32 and received by light-receiving element 33. In this embodiment, black plastic is used. Rubber can also be used instead of plastic. Alternatively, only the surface can be made of this material, or treatment can be applied.

[0094] As described above, light-emitting element 32 emits directional light, but even then, it also emits light in a direction somewhat tilted relative to axis 321 of maximum luminous intensity. Thus, a portion of the light traveling in a direction tilted relative to axis 321 of maximum luminous intensity is incident on the wall surface of light-emitting-side light passage hole 352, thereby suppressing emission outside element cover 35. Similarly, a portion of the light traveling in a direction tilted relative to axis 331 of maximum received light intensity is incident on the wall surface of light-receiving-side light passage hole 353, thereby suppressing detection of this light by light-receiving element 33. Furthermore, because light-emitting element 32 and light-receiving element 33 emit and receive directional light, even if element cover 35 is made thinner than the height of the cylindrical light-emitting element housing and light-receiving element housing used in the electronic balance described in Non-Patent Document 1, the spread of emitted and incident light can be suppressed to the same or greater extent as in the electronic balance described in Non-Patent Document 1, thereby preventing detection of a user's hand, etc., over a wider range than necessary.

[0095] Furthermore, in this embodiment, the element cover 35 can be omitted. By omitting the element cover 35, the thickness of the non-contact sensor 30 (excluding the substrate holder 37) can be further reduced. Alternatively, a cover that covers only one of the light-emitting element 32 and the light-receiving element 33 can be used.

[0096] A substrate fixing member 37 for fixing the substrate 31 to the frame of the operation panel unit 12 is provided below the substrate 31. The substrate fixing member 37 is formed by bending a plate material punched into a predetermined shape, and includes a frame contact portion 371 that contacts the upper surface of the lower frame wall 121 forming the lower side of the frame of the operation panel unit 12; a central upright portion 372 that is bent so as to stand upright relative to the frame contact portion 371; left and right upright portions 373 and 374 that are formed by bending the central upright portion 372 90 degrees at folds in a direction approximately longitudinal to the left and right (details will be described later); and left and right protrusions 375 and 376 that protrude upward from the left and right upright portions 373 and 374, respectively. The frame contact portion 371 is provided with a hole 3711 through which a bolt 391 is passed to secure the frame contact portion 371 to the lower frame wall 121. Meanwhile, the base plate 31 is provided with a left insertion hole 381 and a right insertion hole 382 into which the left protrusion 375 and the right protrusion 376 of the base plate fixing member 37 are respectively inserted.

[0097] When the frame contact portion 371 is positioned so that its plate surface contacts the upper surface of the lower frame wall 121, the plate surface of the central upright portion 372 faces perpendicular to the upper surface of the lower frame wall 121. However, the fold between the left upright portion 373 and the central upright portion 372, and the fold between the right upright portion 374 and the central upright portion 372, are inclined from the upper left to the lower right. Consequently, the upper end of the left upright portion 373 is located slightly below the upper end of the right upright portion 374. Consequently, the left protrusion 375 is located slightly below the right protrusion 376. As a result, when the left protrusion 375 is fitted into the left fitting hole 381 of the base plate 31 and the right protrusion 376 is fitted into the right fitting hole 382 of the base plate 31, the base plate 31 is fixed to the base plate fixing member 37, and then the frame contact portion 371 is fixed to the upper surface of the lower frame wall 121 using a bolt 391 or the like, the base plate 31 is in a state of being tilted relative to the lower frame wall 121 so that the left fitting hole 381 side is slightly lower than the right fitting hole 382 side ( Figure 6 ).

[0098] Thus, when the non-contact sensor 30 is fixed to the lower housing wall 121 and housed within the operation panel unit 12, the substrate 31 is substantially parallel to the upper housing wall 122 of the operation panel unit 12, and both are tilted at substantially the same angle relative to the lower housing wall 121. By tilting the upper housing wall 122 in this manner, a user seated facing the electronic balance 1 placed on a table can view the display area 41 in a natural posture or operate the operation keys of the non-contact sensor 30 or the operation area 42.

[0099] An infrared ray transmission window 123 provided in the upper housing wall 122 is arranged on the upper surface of the element cover 35 of the proximity sensor 30 .

[0100] A space corresponding to the height of the central upright portion 372 is provided between the lower housing wall 121 of the operation panel unit 12 and the substrate 31 of the proximity sensor 30. Devices for controlling the motion control unit 50 or the input display unit 40 can be accommodated in this space.

[0101] The operation of the electronic balance 1 of this embodiment is the same as that of a conventional electronic balance, except for the opening / closing of the door of the windshield 20. The opening / closing operation of the door of the windshield 20 will be described below. As described, the electronic balance 1 of this embodiment can open / close the right door 24, the left door 25, and the upper door 26.

[0102] When the right door 24 is closed, if the user extends their hand or the like to the right non-contact sensor 301, the right non-contact sensor 301 transmits a detection signal. Upon receiving the detection signal, the motion control unit 50 controls the drive motor for the right door 24, thereby opening the right door 24. When the right door 24 is open, if the user extends their hand or the like to the right non-contact sensor 301, the right non-contact sensor 301 transmits a detection signal. Upon receiving the detection signal, the motion control unit 50 controls the drive motor for the right door 24, thereby closing the right door 24.

[0103] When the left door 25 is closed (or open), when the user extends his hand to the left non-contact sensor 302, the left non-contact sensor 302 sends a detection signal. The motion control unit 50 that receives the detection signal controls the drive motor for the left door 25, thereby opening (or closing) the left door 25.

[0104] When the user extends his hand to the right non-contact sensor 301 and the left non-contact sensor 302 at the same time for a short time (for example, less than 3 seconds) and then leaves immediately, the right non-contact sensor 301 and the left non-contact sensor 302 send a detection signal in the short time. The motion control unit 50 that receives the detection signal controls the drive motor for the right door 24 and the drive motor for the left door 25, thereby opening the right door 24 and the left door 25 at the same time (if they were closed before) or closing them (if they were open before).

[0105] When the upper side door 26 is closed (or open), when the user extends his hands to the right non-contact sensor 301 and the left non-contact sensor 302 at the same time for a long time (for example, more than 3 seconds), the right non-contact sensor 301 and the left non-contact sensor 302 send detection signals for the long time, and the motion control unit 50 that receives the detection signal controls the drive motor for the upper side door 26, thereby opening (or closing) the upper side door 26.

[0106] According to the electronic balance 1 of this embodiment, by using a directional light-emitting element 32 and a similarly directional light-receiving element 33, there is no need for a cylindrical member to limit the light-emitting range or the light-receiving range. This can reduce the height of the non-contact sensor 30. Therefore, the operation panel unit 12, which is located in front of and below the weighing pan 11 and windshield 20, can accommodate the non-contact sensor 30 without increasing its thickness.

[0107] The present invention is not limited to the above-described embodiment and is subject to various modifications within the scope of the present invention. While modifications are conveniently described in the description of the above-described embodiment, other modifications are also possible. For example, in the above-described embodiment, the contactless sensor 30 is used to open / close the door of the windshield 20. Alternatively, the contactless sensor 30 may be used as a switch for switching items displayed on the input display unit (operation panel) 40 or as a switch for setting a zero point (setting the weight when the switch is operated to zero).

[0108] [form]

[0109] It will be understood by those skilled in the art that the above-described exemplary embodiments are specific examples of the following aspects.

[0110] (First item)

[0111] The electronic balances covered by the first item include:

[0112] A non-contact sensor comprising: a substrate, a directional light emitting element fixed to a surface of the substrate so as to point toward a target detection space, and a directional light receiving element fixed to the surface of the substrate so as to be separated from the light emitting element and point toward the target detection space; and

[0113] The operation control unit controls the operation of a predetermined portion of the electronic balance based on the detection signal of the non-contact sensor.

[0114] According to the electronic balance of the first aspect, by using a directional light emitting element and a similarly directional light receiving element, there is no need to use a cylindrical member for limiting the light emitting range or the light receiving range.

[0115] (Second item)

[0116] The electronic balance involved in the second item is based on the electronic balance involved in the first item, and also includes: an element cover, which accommodates the light-emitting element and / or the light-receiving element, and the element cover has: a hole extending along the direction pointed by the light-emitting element and / or the light-receiving element and open at the upper end.

[0117] According to the electronic balance of the second aspect, not only are the light-emitting element and / or light-receiving element directional, but they are also housed in a hole in an element cover extending in the direction they point and open at the top. This reduces the range of light emitted by the light-emitting element and / or the range of light received by the light-receiving element, thereby preventing the non-contact sensor from accidentally detecting the user's hand, etc. By ensuring not only the directional hole in the element cover but also the directional nature of the light-emitting element and / or light-receiving element, the non-contact sensor can be made thinner overall while preventing accidental detection to the same or greater extent than with conventional cylindrical light-emitting element or light-receiving element housings.

[0118] (Item 3)

[0119] The electronic balance referred to in the third item is an electronic balance according to the first or second item, wherein

[0120] The non-contact sensors are housed in an operation panel unit provided in front of and below the weighing pan.

[0121] According to the electronic balance according to the third aspect, since the height of the non-contact sensor can be suppressed, the non-contact sensor can be accommodated without increasing the thickness of the operation panel unit provided in front of and below the weighing pan.

[0122] (Item 4)

[0123] The electronic balance referred to in item 4 is the electronic balance referred to in any one of items 1 to 3, further comprising:

[0124] a windshield covering the weighing pan, a door for opening / closing the windshield, and a power source for opening / closing the door,

[0125] The motion control unit controls the power source according to the detection signal of the non-contact sensor.

[0126] According to the electronic balance of the fourth aspect, the user operates the non-contact sensor, thereby opening and closing the door of the windshield without contacting the door.

Claims

1. An electronic balance, characterized in that: include: Non-contact sensor with: substrate; A light emitting element is fixed on the surface of the substrate in a direction pointing to the target detection space and has directivity; and a light receiving element, fixed on the surface of the substrate in a manner separated from the light emitting element and pointing toward the target detection space, and having directivity; and an action control unit that controls the action of a predetermined portion of the electronic balance according to a detection signal from the non-contact sensor; in, The light emitting element has a rectangular bottom surface, The maximum luminous intensity axis of the light emitting element is perpendicular to the bottom surface, The bottom surface is inclined relative to the surface of the substrate, The light emitting element is fixed to the surface of the substrate by solder at two points near both ends of one side of the bottom surface of the rectangle. A hole is provided on the surface of the substrate, and the hole is located between two points of the solder that fixes the light emitting element.

2. The electronic balance according to claim 1, characterized in that Also includes: an element cover for housing the light emitting element and / or the light receiving element, The element cover has a hole extending in a direction in which the light emitting element and / or the light receiving element points and having an open upper end.

3. The electronic balance according to claim 1 or 2, characterized in that: The non-contact sensors are housed in an operation panel unit provided in front of and below the weighing pan.

4. The electronic balance according to claim 1 or 2, characterized in that: Also includes: A windshield covering the weighing pan; opening / closing the door of said windshield; as well as a power source for opening / closing the door, The motion control unit controls the power source according to the detection signal of the non-contact sensor.

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