Indicators and measuring devices

Abstract

To provide an indicator and measuring device that can implement electrostatic discharge countermeasures even in a structure where the entire display unit cannot be electromagnetically shielded, and that can reduce adverse effects caused by increased intensity of unwanted radiation. [Solution] The indicator 4 comprises an insulating housing 41, an insulating panel 42 mounted on the front of the housing 41 and having a display window 421, a circuit board 43 provided inside the housing 41 and on which electronic components 435, 436, and 437 are mounted, a display unit 44 mounted on the circuit board 43 and emitting light to the outside of the panel 42 through the display window 421, a light-transmitting conductive film 45 provided away from the panel 42 at a position opposite the display unit 44, a holding member 46 sandwiched between the panel 42 and the conductive film 45 to hold the conductive film 45, and an edge portion 47 which is conductive and provided at one end 441 and the other end 442 of the display unit 44, and is electrically connected to the reference potential portion of the circuit board 43 and the conductive film 45.

Description

Technical Field

[0001] The present invention relates to an indicator that displays measurement values of physical quantities such as mass, flow rate, and pressure, and a measuring device provided with the indicator. The scope of the indicator includes a display.

Background Art

[0002] For example, in a display device provided with a liquid crystal display element or the like, as a countermeasure against static electricity and unnecessary radiation, the entire display unit of the liquid crystal display element or the like is surrounded by a conductor to be electromagnetically shielded, noise is attenuated through a ferrite ring, and the conductor that electromagnetically shields the entire display unit is connected to the ground (that is, maintained at the ground potential).

[0003] For example, Patent Document 1 discloses a display device that can reduce the adverse effects caused by an increase in the intensity of unnecessary radiation while maintaining countermeasures against static electricity. In the display device described in Patent Document 1, a conductive film made of a transparent or translucent appropriate conductive material is laminated and disposed in front of the liquid crystal display element (for example, on an optical filter made of an acrylic resin). Further, the periphery of the optical filter and the conductive film is fixed to the front edge of the frame via a holding member made of conductive rubber. Thereby, a current path is formed surrounding the liquid crystal display element. In other words, an electromagnetic shield is configured surrounding the liquid crystal display element.

[0004] However, depending on the structure around the display unit, it may not be possible to electromagnetically shield the entire display unit. For example, in the electromagnetic shield structure described in Patent Document 1, it is necessary to electromagnetically shield the entire display unit. Therefore, in a structure where the entire display unit cannot be electromagnetically shielded, there is a problem that countermeasures against static electricity cannot be realized and the adverse effects caused by an increase in the intensity of unnecessary radiation cannot be reduced.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] The present invention has been made in view of the above circumstances, and aims to provide an indicator and measuring device that can implement electrostatic discharge countermeasures even in a structure where the entire display unit cannot be electromagnetically shielded, and that can reduce adverse effects caused by increased intensity of unwanted radiation. [Means for solving the problem]

[0007] A first aspect of the present invention is an indicator comprising: an insulating housing; an insulating panel mounted on the front part of the housing and having a display window; a circuit board provided inside the housing and on which electronic components are mounted; a display unit mounted on the circuit board and emitting light to the outside of the panel through the display window; a conductive film that transmits the light and is provided away from the panel at a position opposite to the display unit; a holding member sandwiched between the panel and the conductive film to hold the conductive film; and conductive edge portions provided at one end and the other end of the display unit and electrically connected to a reference potential portion of the circuit board and the conductive film.

[0008] A second aspect of the present invention is a measuring device comprising a detector for detecting a physical quantity, and an indicator according to the first aspect which receives a signal relating to the measured value of the physical quantity output from the detector and displays the measured value. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide an indicator and measuring device that can implement electrostatic discharge countermeasures even in a structure where the entire display unit cannot be electromagnetically shielded, and that can reduce adverse effects caused by increased intensity of unwanted radiation. [Brief explanation of the drawing]

[0010] [Figure 1] This is a perspective view showing the measuring device according to this embodiment. [Figure 2] This is a cross-sectional view showing the indicator according to this embodiment. [Figure 3] This is an enlarged view of region A1 shown in Figure 2. [Figure 4] This is an exploded view showing the indicator in this embodiment. [Figure 5] This is an exploded view showing the plate and power supply board of this embodiment. [Figure 6] This is a plan view showing the display section and edge of this embodiment. [Modes for carrying out the invention]

[0011] Embodiments of the present invention will be described below with reference to the drawings. The embodiments described below are preferred examples of the present invention and are subject to various technically preferred limitations. However, the scope of the present invention is not limited to these embodiments unless otherwise specified in the following description. In addition, similar components are denoted by the same reference numerals in the drawings, and detailed descriptions are omitted as appropriate.

[0012] Figure 1 is a perspective view showing the measuring device according to this embodiment. Figure 2 is a cross-sectional view showing the indicator according to this embodiment. Figure 3 is an enlarged view of region A1 shown in Figure 2. Figure 4 is an exploded view showing the indicator in this embodiment. Figure 5 is an exploded view showing the plate and power supply board of this embodiment. Figure 6 is a plan view showing the display section and edge section of this embodiment. Figure 2 corresponds to the cross-sectional view at cross-section AA shown in Figure 1.

[0013] As shown in FIG. 1, the measuring device 2 according to the present embodiment includes a detector 3 and an indicator 4. In the present specification, the scope of the "indicator" includes a device for displaying a measured value of a physical quantity such as mass, flow rate, pressure, temperature, voltage, and current, that is, a display. The detector 3 and the indicator 4 are electrically connected to each other by a connection wiring 63.

[0014] The detector 3 detects physical quantities such as mass, flow rate, pressure, temperature, voltage, and current. In the following description, the case where the detector 3 detects the mass of the measurement object is taken as an example. That is, the "mass" of the present embodiment is an example of the "physical quantity" of the present invention. The detector 3 has a load cell (not shown) and detects the mass of the measurement object. Further, the detector 3 has a mounting table 31 as a load loading portion on which the measurement object is placed and a load is applied.

[0015] The detector 3 receives an instruction signal regarding the detection of the mass of the measurement object from the indicator 4 through the signal line of the connection wiring 63, and detects the mass of the measurement object. Further, the detector 3 transmits a signal regarding the measured value of the mass of the measurement object to the indicator 4 through the signal line of the connection wiring 63. Electric power is supplied from the indicator 4 to the detector 3 through the power supply line of the connection wiring 63.

[0016] The indicator 4 transmits an instruction signal regarding the detection of the mass of the measurement object to the detector 3 through the signal line of the connection wiring 63. Further, the indicator 4 receives a signal regarding the measured value of the mass of the measurement object from the detector 3 through the signal line of the connection wiring 63, and displays the mass value (that is, the measured value of the physical quantity) of the measurement object.

[0017] As shown in FIGS. 2 to 4, the indicator 4 includes a housing 41, a panel 42, a main board 43, a display unit 44, a conductive film 45, a holding member 46, and an edge portion 47. Further, the indicator 4 further includes a plate 48, a power supply board 49, a ground wire 51, and a filter member 52.

[0018] The housing 41 is formed of a material having insulation properties. Examples of the material of the housing 41 include resins such as ABS (Acrylonitrile Butadiene Styrene). However, the material of the housing 41 is not necessarily limited to the ABS resin.

[0019] The housing 41 has a substantially rectangular cylindrical shape and houses a main board 43, a display unit 44, a conductive film 45, a holding member 46, an edge portion 47, a power supply board 49, a ground wire 51, and a filter member 52. As shown in FIG. 4, the housing 41 has a display window 412 formed as an opening.

[0020] The panel 42 is formed of a material having insulation properties. Examples of the material of the panel 42 include resins such as PET (Polyethylene terephthalate). However, the material of the panel 42 is not necessarily limited to the PET resin.

[0021] The panel 42 is attached to the front portion of the housing 41 and has a display window 421. Here, in the present specification, "front" refers to the direction in which the display unit 44 emits light or the emitting side. Also, in the present specification, "rear" refers to the direction opposite to the direction in which the display unit 44 emits light or the side opposite to the emitting side.

[0022] The display window 421 of the panel 42 is not formed as an opening but is a portion where printing is not applied to the base material (e.g., PET resin) of the panel 42. The display window 421 of the panel 42 is provided at a position facing the display window 412 of the housing 41. When the base material of the panel 42 is a material having light transmissivity such as, for example, PET resin, the display window 421 of the panel 42 can transmit, for example, light emitted from the display unit 44.

[0023] Users of the indicator 4 can input instructions, such as those related to detecting the mass of an object to be measured, by operating the control unit 422 (see Figure 1) provided on the panel 42 with their fingers or other means.

[0024] As shown in Figures 2 and 4, the main board 43 is located inside the housing 41 and is fixed to the support portion 411 of the housing 41 by fastening members 72 such as screws. The main board 43 in this embodiment is an example of the "circuit board" of the present invention.

[0025] The main board 43 is equipped with various electronic components. As shown in Figures 2 and 4, for example, electronic components such as the arithmetic processing unit 435, the memory unit 436, and the operating components 437 are mounted on the main board 43. The operating components 437 are, for example, switches that can be operated by the user with their fingers.

[0026] The arithmetic processing unit 435 is, for example, a CPU (Central Processing Unit), and reads programs stored in the memory unit 436 and performs various calculations and processes. For example, the arithmetic processing unit 435 transmits an instruction signal related to the detection of the mass (physical quantity) of the object to be measured to the detector 3 through the signal line of the connection wiring 63, based on a signal input by the user in response to the operation of the operating component 437. Alternatively, the arithmetic processing unit 435 receives a signal related to the measured value of the mass (physical quantity) of the object to be measured from the detector 3 through the signal line of the connection wiring 63, and performs processing to calculate the mass value (measured value) of the object to be measured or to display the mass value (measured value) of the object to be measured on the display unit 44.

[0027] The memory unit 436 is, for example, a semiconductor memory such as ROM (Read Only Memory) or RAM (Random Access Memory), or a hard disk drive (HDD), and stores the result values ​​of calculations and processing performed by the arithmetic processing unit 435, as well as various information related to measurements. Furthermore, the electronic components mounted on the main board 43 are not limited to the arithmetic processing unit 435, the memory unit 436, and the operating components 437.

[0028] The display unit 44 is a display device such as a liquid crystal panel or an organic EL panel, and is mounted on the main board 43. The display unit 44 emits light to the outside of the panel 42 (i.e., forward) through the display window 412 of the housing 41 and the display window 421 of the panel 42, and displays various information such as the mass value (measured value) of the object being measured. Therefore, users can visually confirm various information such as the mass value (measured value) of the object being measured, which is displayed by the display unit 44, through the display window 421 of the panel 42.

[0029] The conductive film 45 is a transparent conductive film formed from a metal oxide such as indium tin oxide (ITO) or indium zinc oxide (IZO). Therefore, the conductive film 45 can transmit light emitted from the display unit 44 to the outside of the panel 42 (i.e., forward).

[0030] As shown in Figures 2 and 3, the conductive film 45 is provided at a position opposite the display unit 44, away from the panel 42. In other words, a layer of air is interposed between the conductive film 45 and the panel 42. The distance between the conductive film 45 and the panel 42 is, for example, about 1 mm to 3 mm. By having a distance of 1 mm or more between the conductive film 45 and the panel 42, it is possible to suppress the occurrence of malfunction phenomena such as Newton's rings. Furthermore, even if the distance between the conductive film 45 and the panel 42 is less than 1 mm, it is possible to suppress the occurrence of malfunction phenomena such as Newton's rings by applying transparent medium ink to the outside of the conductive film 45. However, the distance between the conductive film 45 and the panel 42 is not limited to 1 mm to 3 mm.

[0031] Specifically, a retaining member 46 is sandwiched between the panel 42 and the conductive film 45. As shown in Figure 4, the retaining member 46 is provided on the outer edge of the conductive film 45 and is attached around the display window 421 of the panel 42 to hold the conductive film 45. The retaining member 46 is made of an insulating material such as rubber. Examples of the retaining member 46 include double-sided adhesive tape.

[0032] Furthermore, as shown in Figures 2 and 3, the conductive film 45 is provided at a position opposite the display unit 44, but at a distance from the display unit 44. In other words, a layer of air is interposed between the conductive film 45 and the display unit 44. The distance between the conductive film 45 and the display unit 44 is, for example, about 1 mm to 3 mm. However, the distance between the conductive film 45 and the display unit 44 is not limited to 1 mm to 3 mm.

[0033] As shown in Figure 3, the conductive film 45 has a first film 451 and a second film 452. The first film 451 is made of a conductive material. The second film 452 is stacked on top of the first film 451 and is made of an insulating material. In other words, the conductive film 45 of this embodiment is a single-sided transparent conductive film. The first film 451 is located on the side of the display portion 44 as viewed from the second film 452, that is, behind the second film 452, and is electrically connected to the edge portion 47.

[0034] The edge portion 47 is formed of a conductive material such as metal. As shown in Figure 6, the edge portion 47 is provided at one end 441 of the display portion 44 and the other end 442 of the display portion 44. In other words, the edge portion 47 is not provided at the end that extends in a direction intersecting the one end 441 and the other end 442 of the display portion 44. As shown in Figure 3, the edge portion 47 is electrically connected to the ground plane 431 of the main substrate 43 and the first film 451 of the conductive film 45. The ground plane 431 in this embodiment is an example of the "reference potential portion" of the present invention.

[0035] The plate 48 is made of a conductive material such as metal and is attached to the rear of the housing 41. By being attached to the rear of the housing 41, the plate 48 functions together with the housing 41 as a housing (i.e., housing box) for the indicator 4.

[0036] As shown in Figures 2 and 5, the power supply board 49 is supported and fixed to the plate 48 by a support member 71. The power supply board 49 has a power supply circuit and supplies power to the main board 43 through a power supply line 53.

[0037] As shown in Figures 2 and 3, the ground wire 51 is electrically connected at one end to at least one of the ground plane 431 and edge 47 of the main board 43. Also, as shown in Figure 5, the other end of the ground wire 51 is fixed to the plate 48 by a fastening member 72 such as a screw. In this way, the plate 48 and the ground wire 51 are electrically connected to each other.

[0038] As shown in Figure 2, the ground wire 51 is connected to a 3-core power cord 61 that is connected to the commercial power supply. As a result, the ground wire 51 is electrically connected to the earth (i.e., the planet) via the ground connection piece 621 provided on the power plug 62 of the 3-core power cord 61. Therefore, the ground plane 431 of the main board 43 is connected to the earth via the ground wire 51 and maintained at earth potential.

[0039] The filter member 52 is installed around the ground wire 51 and is made of a magnetic material that has a high-frequency component attenuation function. Examples of the filter member 52 include a ferrite ring. The filter member 52 attenuates the high-frequency current components flowing through the ground wire 51.

[0040] Generally, to prevent static electricity and unwanted radiation, the entire display unit is surrounded by a conductor for electromagnetic shielding, and this electromagnetically shielded conductor is connected to the ground. However, depending on the structure surrounding the display unit, it may not be possible to electromagnetically shield the entire display unit, and thus static electricity and unwanted radiation countermeasures may not be achieved.

[0041] In contrast, as described above, in the measuring device 2 and indicator 4 according to this embodiment, the conductive film 45 is provided at a position facing the display unit 44. Furthermore, conductive edges 47 are provided at one end 441 and the other end 442 of the display unit 44, and are electrically connected to the ground plane 431 of the main substrate 43 and the first film 451 of the conductive film 45. Therefore, at least a part of the display unit 44 is electromagnetically shielded by being surrounded by the conductive film 45, the edges 47, and the ground plane 431.

[0042] As a result, the measuring device 2 and indicator 4 according to this embodiment can implement electrostatic discharge countermeasures and reduce adverse effects caused by increased intensity of unwanted radiation, even if the display unit 44 is located inside an insulating housing 41 and near the display window 421 of an insulating panel 42, that is, even if the entire display unit 44 is not electromagnetically shielded. In other words, the measuring device 2 and indicator 4 according to this embodiment can implement electrostatic discharge countermeasures and reduce adverse effects caused by increased intensity of unwanted radiation, even if the structure does not allow for the entire display unit 44 to be electromagnetically shielded.

[0043] Furthermore, by sandwiching the retaining member 46 between the panel 42 and the conductive film 45, the conductive film 45 is positioned away from the panel 42 at a location facing the display unit 44. In other words, a double structure of the insulating panel 42 and the conductive film 45, provided via the retaining member 46, is positioned facing the display unit 44. Therefore, even if static electricity is generated on the insulating panel 42, the double structure of the panel 42 and the conductive film 45 can attenuate the static electricity, and it is possible to suppress spark discharge from, for example, burrs on the edges of the conductive film 45. As a result, the measuring device 2 and indicator 4 according to this embodiment can achieve even greater static electricity countermeasures, even if the entire display unit 44 is not electromagnetically shielded.

[0044] Furthermore, the ground plane 431 of the main board 43 is electrically connected to the earth wire 51, and is connected to the earth via the earth wire 51. Therefore, the ground plane 431 of the main board 43 is maintained at the earth potential. As a result, the measuring device 2 and indicator 4 according to this embodiment can more reliably implement electrostatic discharge countermeasures even if the entire display unit 44 is not electromagnetically shielded, and can further reduce adverse effects caused by increased intensity of unwanted radiation.

[0045] Furthermore, a conductive plate 48 is attached to the rear of the housing 41 and is electrically connected to the ground wire 51. In addition, a filter member 52 is installed around the ground wire 51 and has a high-frequency component attenuation function. Therefore, even if static electricity is generated on the conductive plate 48 attached to the rear of the housing 41, the filter member 52 can attenuate the high-frequency current component that flows from the conductive plate 48 through the ground wire 51 toward the ground plane 431 of the main board 43. As a result, the measuring device 2 and indicator 4 according to this embodiment can suppress the influence of the high-frequency current component flowing from the conductive plate 48 through the ground wire 51 toward the ground plane 431 of the main board 43 on the main board 43, thereby achieving even greater static electricity countermeasures.

[0046] Embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the claims. The configurations of the above embodiments can be partially omitted or combined in any way different from those described above. [Explanation of Symbols]

[0047] 2: Measuring device, 3: Detector, 4: Indicator, 31: Platform, 41: Housing, 42: Panel, 43: Main board, 44: Display unit, 45: Conductive film, 46: Holding member, 47: Edge, 48: Plate, 49: Power supply board, 51: Ground wire, 52: Filter member, 53: Power supply line, 61: 3-core power cord, 62: Power plug, 63: Connection wiring, 71: Support member, 72: Fastening member, 411: Support part, 412: Display window, 421: Display window, 422: Operation unit, 431: Ground plane, 435: Calculation processing unit, 436: Memory unit, 437: Operating parts, 441: End, 442: End, 451: First film, 452: Second film, 621: Grounding connector

Claims

1. An insulating housing, A panel having insulating properties, mounted on the front part of the housing, and having a display window, A circuit board on which electronic components are mounted is provided inside the aforementioned housing, A display unit mounted on the circuit board and emitting light to the outside of the panel through the display window, A conductive film that transmits light is provided at a position opposite the display unit, away from the panel, A retaining member sandwiched between the panel and the conductive film to hold the conductive film, The edge portion is electrically conductive and provided at one end and the other end of the display portion, and is electrically connected to the reference potential portion of the circuit board and the conductive film, An indicator characterized by having the following features.

2. The conductive film is A first conductive film, A second insulating film is provided stacked on the first film, It has, The indicator according to claim 1, characterized in that the first film is arranged on the side of the display portion with respect to the second film and is electrically connected to the edge portion.

3. The indicator according to claim 1, further comprising an earth wire provided inside the housing for electrically connecting the reference potential unit and the earth.

4. A conductive plate, attached to the rear of the housing and electrically connected to the ground wire, A filter member installed around the aforementioned ground wire and having a high-frequency component attenuation function, The indicator according to claim 3, further comprising the features described above.

5. A detector that detects physical quantities, An indicator according to any one of claims 1 to 4, which receives a signal relating to the measured value of the physical quantity output from the detector and displays the measured value, A measuring device characterized by being equipped with the following features.

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