Electronic balance

Abstract

To provide an electronic balance capable of reducing space required for installing a non-contact sensor.SOLUTION: An electronic balance 1 includes: a non-contact sensor 30 having a substrate 31, a light emitting element 32 that has directivity and being fixed on a surface of the substrate 31 so as to be directed toward a target detection space, and a light receiving element 33 having directivity and fixed on a surface of the substrate 31 so as to be separated from the light emitting element 32 and directed to the target detection space; and an operation control unit 50 for controlling operation of a predetermined section of the electronic balance 1 in accordance with a detection signal of the non-contact sensor 30.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] In laboratories, electronic balances are used to measure the mass (weight) of objects such as powders. These balances are equipped with a windshield that surrounds the weighing pan to prevent the effects of convection and other factors in the measurement environment. This windshield has an openable door. When taking a measurement, the windshield door is opened, the object to be measured is placed on the weighing pan of the electronic balance, the windshield door is closed, and the weighing value on the display is confirmed to obtain the weight value of the object to be measured.

[0003] Previously, users manually opened and closed the windshield door, but in recent years, electronic balances with automatic windshield door opening and closing capabilities have become widespread. While some automatic door opening and closing operations require the user to press a physical switch, 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 these electronic balances, when the windshield door is closed and the user places their hand over the non-contact sensor, the drive motor operates to open the door. When the door is open and the user places their hand over the non-contact sensor, the drive motor operates to close the door. Using such a non-contact sensor allows the user to operate the balance simply by placing their hand close to the sensor, eliminating the need to release a reagent bottle or medicine spoon each time the door is opened or closed. Furthermore, because the user does not need to touch a switch, the risk of contact transmission of infectious diseases, such as COVID-19, through the electronic balance can be prevented.

[0004] The electronic balance described in Non-Patent Document 1 uses a reflective non-contact sensor. Specifically, it uses an integrated sensor device in which a light-emitting element (light-emitting diode: LED) and a light-receiving element (photodiode: PD) are arranged. When a user holds their hand or the like near the sensor device without contact, light having a specific wavelength generated by the light-emitting element is reflected and scattered by the hand or the like, and the reflected and scattered light having the specific wavelength is detected by the light-receiving element, thereby detecting that the hand or the like has been held near the sensor device.

[0005] If the light emitted from the light-emitting element spreads over an unnecessarily wide area, or if the light-receiving element receives light from an unnecessarily wide area, the light-receiving element may detect reflected or scattered light even when the user's hand is positioned to the side of the sensor device, potentially opening or closing the windshield door unintentionally. Therefore, in the electronic balance described in Non-Patent Document 1, the light-emitting element is arranged in a cylindrical light-emitting element housing with an opening at one end, axially spaced from the opening (toward the back), and the light-receiving element is arranged in a similarly cylindrical light-receiving element housing, axially spaced from the opening (toward the back). The light-emitting element housing and the light-receiving element housing are then fixed at an angle so that their axes intersect in the intended detection space. By positioning the light-emitting element further back than the opening of the light-emitting element housing, the spread of the emitted light is suppressed, and by positioning the light-receiving element further back than the opening of the light-receiving element housing, the range of light incident on the light-receiving element is suppressed. This prevents the sensor device from detecting the user's hand over a wider area than necessary, and prevents the user from opening and closing the windshield door unintentionally. However, if the light-emitting direction of the light-emitting element and the opening direction of the light-emitting element accommodating section are to be aligned, the light-emitting element must be fixed using the light-emitting element accommodating section, which creates a problem in that the light-emitting element accommodating section must be large enough to fix the light-emitting element. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2019-194575 [Non-patent literature]

[0007] [Non-Patent Document 1] "Reference Manual for Analytical Balances and Comparators XPR", [online], publication date unknown, Mettler-Toledo K.K., [Retrieved 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 [Problem to be solved by the invention]

[0008] To improve operability for analysts, many electronic balances have a flat operation panel unit that houses a display device that displays the measured weight, etc., as well as switches for switching the displayed content, etc., located in front of the weighing pan and windshield, but below the weighing pan so as not to obscure it from the user's perspective. It is desirable to install a non-contact sensor for opening and closing the door within this operation panel unit, since its detection space should be located above (or in front of) this operation panel unit. However, the electronic balance described in Non-Patent Document 1 requires the cylindrical light-emitting element housing and light-receiving element housing to be installed upright, which requires the non-contact sensor to be a certain height, and the operation panel unit that houses it is also thick.

[0009] 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. [Means for solving the problem]

[0010] The electronic balance according to the present invention, which has been made to solve the above problems, comprises: a non-contact sensor having a substrate, a directional light-emitting element fixed on a surface of the substrate so as to be oriented toward a target detection space, and a directional light-receiving element fixed on the surface of the substrate, spaced apart from the light-emitting element, so as to be oriented toward the target detection space; an operation control unit that controls the operation of a predetermined part of the electronic balance in response to a detection signal from the non-contact sensor; Equipped with.

[0011] The electronic balance of the present invention uses a directional light-emitting element and a similarly directional light-receiving element, eliminating the need for a cylindrical member to limit the light-emitting or light-receiving range. This reduces the height of the non-contact sensor. As a result, the non-contact sensor can be housed in the operation panel unit located in front of and below the weighing pan and windshield without increasing its thickness. [Effects of the Invention]

[0012] According to the electronic balance of the present invention, the space required for installing the non-contact sensor can be reduced. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a perspective view showing an embodiment of an electronic balance according to the present invention. [Figure 2] FIG. 1 is a top view showing an electronic balance according to an embodiment of the present invention. [Figure 3] FIG. 2 is an exploded perspective view of a non-contact sensor included in the electronic balance of the present embodiment. [Figure 4] FIG. 3 is a cross-sectional view of a non-contact sensor included in the electronic balance of the present embodiment. [Figure 5] FIG. 10 is a cross-sectional view showing a state during an operation of fixing the light-emitting element to the substrate. [Figure 6] FIG. 10 is a cross-sectional view showing a state in which the non-contact sensor is fixed inside the housing of the operation panel unit. DETAILED DESCRIPTION OF THE INVENTION

[0014] An embodiment of the electronic balance according to the present invention will be described with reference to Figures 1 to 6. As shown in Figure 1, the electronic balance 1 of this embodiment comprises a base 101 and a rear wall 10 2 The electronic balance comprises an electronic balance main body 10 having a base 101, a weighing pan 11 on which an object to be measured is placed, an operation panel unit 12, and a windshield 20 that surrounds the weighing pan 11. The space surrounded by the windshield 20 forms 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) located inside the base 101.

[0015] The windshield 20 includes a front wall 22, a rear wall 23, a frame 21 that supports the front wall 22 and connects the front wall 22 and the rear wall 23 at their upper ends, and a right door 24, a left door 25, and an upper door 26 that are supported on the frame 21 so as to be able to open and close. The front wall 22, the right door 24, the left door 25, and the upper door 26 are made of a transparent material such as glass. The 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) powered by a drive motor disposed within the rear wall 102 when a user performs an operation described below. Each door is also provided with a grip 27, which the user can grip to manually open and close. The rear wall 23 is provided with a static eliminator 13 that removes static electricity from the weighing chamber.

[0016] The operation panel unit 12 is located in front of the windshield 20, below the weighing pan 11 so as not to obscure it from the user's perspective. The operation panel unit 12 is provided with a power switch 14, an input display unit (operation panel) 40, and two non-contact sensors (a right non-contact sensor 301 and a left non-contact sensor 302). The input display unit 40 is a combination of an LCD panel and a touchpad, and includes a display area 41 where measurement values and setting items are displayed, and an operation area 42 where images representing operation keys and operation buttons are displayed. The operation panel unit 12 also houses an operation control unit 50 that controls the opening and closing operations of the right door 24, the left door 25, and the upper door 26 in response to detection signals from the right non-contact sensor 301 and the left non-contact sensor 302. The operation control unit 50 is embodied by a combination of hardware, such as a CPU, and software that operates the hardware.

[0017] The right non-contact sensor 301 is disposed on the right side of the input display unit 40, and the left non-contact sensor 302 is disposed on the left side of the input display unit 40. When an object such as a hand is brought close, the right non-contact sensor 301 and the left non-contact sensor 302 detect the object without contact as shown by the imaginary line in Fig. 2. The right non-contact sensor 301 and the left non-contact sensor 302 have the same configuration. Hereinafter, the right non-contact sensor 301 and the left non-contact sensor 302 will be collectively referred to as "non-contact sensors 30."

[0018] As shown in the perspective view of Fig. 3 (which is separated into three parts for ease of understanding) and the cross-sectional view of Fig. 4, the non-contact sensor 30 has a substrate 31, and a light-emitting element 32 and a light-receiving element 33 fixed to the surface of the substrate 31 at a distance from each other (other components of the non-contact sensor 30 will be described later). The light-emitting element 32 is an element that emits infrared light having a predetermined wavelength band, and the light-receiving element 33 is an element that detects infrared light in that wavelength band.

[0019] The light-emitting element 32 uses an LED package in which an LED is sealed in a lens-shaped sealing resin. Because the sealing resin is lens-shaped, the light generated by the LED, passing through the sealing resin, and emitted outside the LED package has directionality. The light-receiving element 33 uses a PD that detects directional light. These LED packages and PDs are manufactured by many manufacturers (some manufacturers produce multiple types), and each manufacturer typically discloses data regarding the directionality of their LED packages and PDs. By referring to this data, it is possible to select an LED package (PD) whose emission (reception) intensity at an angle tilted 60° from the angle at which the emission (reception) intensity is maximum is less than half of that maximum. The angle is preferably 45° or less, and more preferably 30° or less.

[0020] Both the light-emitting element 32 and the light-receiving element 33 are fixed to the substrate 31 so as to be oriented toward the target detection space. Specifically, the orientations of both elements are set so that the axis extending in the direction in which the light-emitting intensity of the light-emitting element 32 is maximized (see FIG. 4; referred to as the "maximum light-emitting intensity axis 321") and the axis extending in the direction in which the light-receiving intensity of the light-receiving element 33 is maximized (see FIG. 4; referred to as the "maximum received-light intensity axis 331") intersect above the substrate 31 (in the case of the right non-contact sensor 301, the space above the operation panel unit 12 to the right, and in the case of the left non-contact sensor 302, the space above the operation panel unit 12 to the left).

[0021] The light emitting element 32 is oriented as described above, with its rectangular bottom surface 322 perpendicular to the maximum light intensity axis 321 tilted relative to the surface of the substrate 31, and is fixed to the surface of the substrate 31 with solder 323 at two points near both ends of one side of the rectangle. A hole 311 is provided on the surface of the substrate 31 between the two points where the solder 323 for fixing the light emitting element 32 is attached, to prevent interference between a part of the bottom surface of the light emitting element 32 and the surface of the substrate 31 when the light emitting element 32 is arranged tilted relative to the surface of the substrate 31, as shown in FIG. 5 . When manufacturing the electronic balance of this embodiment, a jig 90 having a slope 92 formed at the same angle of inclination relative to the bottom surface 91 as the angle at which the light emitting element 32 is tilted is placed on the surface of the substrate 31, and soldering is performed with the bottom surface 322 of the light emitting element 32 in contact with the slope 92 of the jig 90.

[0022] Meanwhile, the light receiving element 33 is fixed to the surface of the substrate 31 so that the entire bottom surface perpendicular to the maximum light receiving intensity axis 331 is in close contact with the surface of the substrate 31. The bottom surface of the light receiving element 33 may be fixed at an angle relative to the surface of the substrate 31, together with or instead of the light emitting element 32. Since the light receiving element 33 is fixed at an angle relative to the substrate 31 in this way, it is no longer necessary to fix the light receiving element 33 with an element cover 35 as in the prior art, and therefore the element cover 35 can be made smaller.

[0023] A visible light source 34 is also provided on the surface of the substrate 31. The visible light source 34 is provided to indicate that the non-contact sensor 30 is operating by lighting up. Note that to prevent the door from opening and closing when a user accidentally brings their hand close to the non-contact sensor 30, the user can stop only the non-contact sensor 30 while the electronic balance 1 is still operating by performing a predetermined operation using the operation keys on the input display unit 40. In this case, the visible light source 34 goes out, indicating that the non-contact sensor 30 is stopped.

[0024] An element cover 35 is provided above the substrate 31 and each element fixed thereto. A protrusion 351 is provided on the underside of the element cover 35, and a protrusion fitting hole 36 corresponding to the protrusion 351 is provided in the substrate 31. The element cover 35 is attached to the substrate 31 by fitting the protrusion 351 into the protrusion fitting hole 36. The element cover 35 also has a light-emitting side light passage hole 352 formed above the light-emitting element 32 with its axis inclined relative to the substrate 31 in accordance with the angle of the maximum light-emitting intensity axis 321, a light-receiving side light passage hole 353 formed above the light-receiving element 33 with its axis perpendicular to the substrate 31 in accordance with the angle of the maximum light-receiving intensity axis 331, and a visible light passage hole 354 formed perpendicular to the substrate 31 above the visible light source 34. The element cover 35 is made of a material that suppresses diffuse reflection on its surface of infrared light in the wavelength range emitted by the light-emitting element 32 and received by the light-receiving element 33. In this embodiment, black plastic is used for the element cover 35. Rubber may be used instead of plastic, or only the surface may be made of such a material or treated.

[0025] Although the light-emitting element 32 emits directional light as described above, it still emits light in a direction tilted to some extent from the maximum light-emitting intensity axis 321. Thus, some of the light traveling in a direction tilted from the maximum light-emitting intensity axis 321 is incident on the wall surface of the light-emitting side light passage hole 352, preventing it from being emitted outside the element cover 35. Similarly, some of the light traveling in a direction tilted from the maximum received light intensity axis 331 is incident on the wall surface of the light-receiving side light passage hole 353, preventing such light from being detected by the light-receiving element 33. However, because the element cover 35 uses the light-emitting element 32 and the light-receiving element 33 that emit and receive directional light, even if the thickness of the element cover 35 is thinner than the height of the cylindrical light-emitting element housing and the light-receiving element housing used in the electronic balance described in Non-Patent Document 1, the spread of the emitted light and the incident light can be suppressed to the same extent as or better than that of the electronic balance described in Non-Patent Document 1, preventing the user's hand, etc., from being detected over an unnecessarily wide area.

[0026] Furthermore, in this embodiment, the element cover 35 may be omitted. By omitting the element cover 35, the thickness of the non-contact sensor 30 (excluding the board fixture 37) can be further reduced. Alternatively, a cover that covers only one of the light-emitting element 32 and the light-receiving element 33 may be used.

[0027] A board fixture 37 is provided below the board 31 for fixing the board 31 to the housing of the operation panel unit 12. The board fixture 37 is made by bending a plate material punched into a predetermined shape, and has a housing contact portion 371 that contacts the upper surface of a lower housing wall 121 that forms the lower side of the housing of the operation panel unit 12, a central standing portion 372 that is bent so as to stand upright from the housing contact portion 371, left standing portion 373 and right standing portion 374 that are formed by bending the left and right sides of the central standing portion 372 at 90° creases in a direction close to the vertical direction (details will be described later), and a left protrusion 375 and a right protrusion 376 that protrude above the left standing portion 373 and right standing portion 374, respectively. The housing contact portion 371 is provided with a hole 3711 through which a bolt 391 that fixes the housing contact portion 371 to the lower housing wall 121 is passed. On the other hand, the substrate 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 substrate fixture 37 are respectively inserted.

[0028] When housing contact portion 371 is positioned so that its plate surface is in contact with the upper surface of lower housing wall 121, the plate surface of central upright portion 372 faces in a direction perpendicular to the upper surface of lower housing wall 121, but the fold between left upright portion 373 and central upright portion 372 and the fold between right upright portion 374 and central upright portion 372 are each inclined from the upper left to the lower right, so that the upper end of left upright portion 373 is located slightly lower than the upper end of right upright portion 374. Therefore, left protrusion 375 is located slightly lower than right protrusion 376. As a result, when the left protrusion 375 is inserted into the left insertion hole 381 of the substrate 31 and the right protrusion 376 is inserted into the right insertion hole 382 of the substrate 31 to fix the substrate 31 to the substrate fixing device 37, and then the housing contact portion 371 is fixed to the upper surface of the lower housing wall 121 using a bolt 391 or the like, the substrate 31 is inclined relative to the lower housing wall 121 so that the left insertion hole 381 side is slightly lower than the right insertion hole 382 side (Figure 6).

[0029] When the non-contact sensor 30 is fixed to the lower housing wall 121 and housed in the operation panel unit 12 in this manner, the board 31 and the upper housing wall 122 of the operation panel unit 12 are substantially parallel to each other, and are both inclined at substantially the same angle relative to the lower housing wall 121. Because the upper housing wall 122 is inclined in this manner, a user seated facing the electronic balance 1 placed on a desk can view the display area 41 and operate the non-contact sensor 30 and the operation keys in the operation area 42 in a natural posture.

[0030] An infrared ray passing window 123 provided in the upper housing wall 122 is arranged on the upper surface of the element cover 35 of the non-contact sensor 30 .

[0031] A space corresponding to the height of the central upright portion 372 is provided between the lower housing wall 121 in the operation panel unit 12 and the substrate 31 of the non-contact sensor 30. This space can accommodate the operation control unit 50, devices for controlling the input display unit 40, and the like.

[0032] The operation of the electronic balance 1 of this embodiment is the same as that of a normal electronic balance, except for the opening and closing of the doors of the windshield 20. The opening and closing operation of the doors of the windshield 20 will be described below. As described above, the right door 24, left door 25, and upper door 26 can be opened and closed in the electronic balance 1 of this embodiment.

[0033] When the right door 24 is closed and a user holds their hand or the like over the right non-contact sensor 301, the right non-contact sensor 301 emits a detection signal, and the operation control unit 50, upon receiving this detection signal, controls the drive motor for the right door 24 to open the right door 24. When the right door 24 is open and a user holds their hand or the like over the right non-contact sensor 301, the right non-contact sensor 301 emits a detection signal, and the operation control unit 50, upon receiving this detection signal, controls the drive motor for the right door 24 to close the right door 24.

[0034] When the user holds their hand or the like over the left non-contact sensor 302 while the left door 25 is closed (or open), the left non-contact sensor 302 emits a detection signal, and the operation control unit 50 receives this detection signal and controls the drive motor for the left door 25, thereby opening (or closing) the left door 25.

[0035] When a user holds their hand or the like over the right non-contact sensor 301 and the left non-contact sensor 302 simultaneously for a short time (for example, less than 3 seconds) and then immediately releases it, the right non-contact sensor 301 and the left non-contact sensor 302 emit a detection signal for that short time, and the operation control unit 50 receiving this detection signal controls the drive motors for the right door 24 and the left door 25, thereby simultaneously opening (if they were previously closed) or closing (if they were previously open).

[0036] When the upper door 26 is closed (or open) and a user holds their hand or the like over the right non-contact sensor 301 and the left non-contact sensor 302 simultaneously for a relatively long period of time (for example, three seconds or more), the right non-contact sensor 301 and the left non-contact sensor 302 emit detection signals for that long period of time, and the operation control unit 50 receiving this detection signal controls the drive motor for the upper door 26, thereby opening (or closing) the upper door 26.

[0037] 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 to use a cylindrical member to limit the light-emitting range or light-receiving range. This makes it possible to reduce the height of the non-contact sensor 30. Therefore, the non-contact sensor 30 can be accommodated in the operation panel unit 12, which is provided in front of and below the weighing pan 11 and windshield 20, without increasing its thickness.

[0038] The present invention is not limited to the above-described embodiment, and various modifications are permitted within the spirit and scope of the present invention. Modifications have been appropriately shown in the description of the above-described embodiment, but other modifications are also possible. For example, in the above-described embodiment, the non-contact sensor 30 is used to open and close the doors of the windshield 20. Instead, the non-contact sensor 30 may be used as a switch for switching the items displayed on the input display unit (operation panel) 40, a switch for setting the zero point (setting the weight to 0 when the switch is operated), or the like.

[0039] [Aspect] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0040] (Section 1) The electronic balances referred to in paragraph 1 are: a non-contact sensor having a substrate, a directional light-emitting element fixed on a surface of the substrate so as to be oriented toward a target detection space, and a directional light-receiving element fixed on the surface of the substrate, spaced apart from the light-emitting element, so as to be oriented toward the target detection space; an operation control unit that controls the operation of a predetermined part of the electronic balance in response to a detection signal from the non-contact sensor; Equipped with.

[0041] According to the electronic balance of paragraph 1, by using a directional light-emitting element and a similarly directional light-receiving element, there is no need to use a cylindrical member to limit the light-emitting range or light-receiving range, which makes it possible to reduce the height of the non-contact sensor.

[0042] (Section 2) The electronic balance according to paragraph 2 is the electronic balance according to paragraph 1, further comprising an element cover that houses the light-emitting element and / or light-receiving element, extends in the direction in which the light-emitting element and / or light-receiving element is pointed, and has a hole with an open upper end.

[0043] According to the electronic balance of paragraph 2, in addition to the light-emitting element and / or the light-receiving element having directionality, they are housed in holes in the element cover that extend in the direction of their direction and have an open top, which limits 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 unintentionally detecting the user's hand, etc. Here, because not only the holes in the element cover but also the light-emitting element and / or the light-receiving element have directionality, the entire non-contact sensor can be made thinner than when a conventional cylindrical light-emitting element housing or light-receiving element housing is used, while preventing unintentional detection to the same extent as or better than before.

[0044] (Section 3) The electronic balances pertaining to paragraph 3 are electronic balances pertaining to paragraph 1 or 2, The non-contact sensor is housed in an operation panel unit provided in front of and below the weighing pan.

[0045] According to the electronic balance of paragraph 3, the height of the non-contact sensor can be reduced, so that the non-contact sensor can be accommodated in the operation panel unit located in front of and below the weighing pan without increasing its thickness.

[0046] (Section 4) The electronic balance according to paragraph 4 is an electronic balance according to any one of paragraphs 1 to 3, The weighing machine further comprises a windshield for covering the weighing pan, a door for opening and closing the windshield, and a power source for opening and closing the door, The operation control unit controls the power source in response to a detection signal from the non-contact sensor.

[0047] According to the electronic balance of paragraph 4, the user can open and close the windshield door by operating the non-contact sensor without touching the door. [Explanation of symbols]

[0048] 1...Electronic balance 10...Main unit 101...Foundation 102...Back wall body 11...Measuring pan 12...Operation panel unit 121...Lower housing wall 122...Upper housing wall 123...Infrared transmission window 13...Static eliminator 14...Power switch 20...Windshield 21...Frame 22...Front wall 23...Rear wall 24...Right side door 25...Left door 26...Upper door 27...Grip 30...Non-contact sensor 301...Right non-contact sensor 302...Left non-contact sensor 31... Circuit board 311...Hole provided in the substrate 32...Light emitting element 321...Maximum luminous intensity axis 322...Bottom surface of light-emitting element 323...Solder 33...Photodetector 331...Maximum light intensity axis 34…Visible light source 35...Element cover 351...protrusion 352...Light-emitting side light passage hole 353…Receiving side light passage hole 354…Visible light passage hole 36…Protrusion insertion hole 37...Board fixture 371... Housing contact part 3711...Hole provided in the housing contact part 372...Central standing section 373...Left standing section 374...Right standing section 375...Left protrusion 376...Right protrusion 381…Left insertion hole 382…Right insertion hole 391...Bolt 40...Input display section 41...Display area 42…Operation area 50...Motion control unit 90...Jig 91...Bottom of jig 92...Jig slope

Claims

1. a non-contact sensor comprising: a substrate; a light-emitting element having directionality fixed on a surface of the substrate so as to be oriented toward a target detection space; and a light-receiving element having directionality fixed on the surface of the substrate at a distance from the light-emitting element so as to be oriented toward the target detection space, wherein either or both of the maximum light-emitting intensity axis of the light-emitting element and the maximum light-receiving intensity axis of the light-receiving element are inclined at an angle other than 90° with respect to the surface of the substrate; an operation control unit that controls the operation of a predetermined part of the electronic balance in response to a detection signal from the non-contact sensor; an element cover having a hole for accommodating the light emitting element and / or the light receiving element, the hole extending at the same angle as the maximum light emitting intensity axis of the light emitting element and / or the maximum light receiving intensity axis of the light receiving element with respect to the surface of the substrate; An electronic balance equipped with:

2. 2. The electronic balance according to claim 1, wherein the non-contact sensor is housed in an operation panel unit provided in front of and below the weighing pan.

3. The weighing machine further comprises a windshield for covering the weighing pan, a door for opening and closing the windshield, and a power source for opening and closing the door, The operation control unit controls the power source in response to a detection signal from the non-contact sensor.

3. The electronic balance according to claim 1 or 2.

4. 4. The electronic balance according to claim 1, wherein the light-emitting element or the light-receiving element is fixed to the surface of the substrate by soldering.

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