JPH0738919U - Field instrument - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent noise and the like from entering from the glass window that is the display part of the display device in a field-installed instrument, and obtain an appropriate shield effect with a simple structure. A glass window 3 is provided in an opening 4 provided in a part of a case 2 of a field instrument 1, and a liquid crystal display device 6 is provided in the vicinity of the glass window. The transparent conductive film 10 is formed so as to be connected to the glass forming the glass window in such a field instrument, and the transparent conductive film 10 is body-grounded.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a field instrument that allows a display device arranged inside a case to be viewed through a glass window.

[0002]

[Prior art]

 For example, various field-installed instruments such as electromagnetic flow meters used for measuring the flow rate (or flow velocity) of process fluids, differential pressure / pressure transmitters, and industrial gas chromatographs are used in various instrument cases. It is generally practiced to install an electric device, an electric circuit, etc., and also to attach a display device for displaying the measured value and the like.

In such a conventional field instrument, in order to make a display device such as a liquid crystal display device visible from the outside, an opening is provided in a part of the case and is covered with a glass window. It was known that such a configuration.

FIG. 2 and FIG. 3 exemplify a transmitter portion case part of an electromagnetic flowmeter having a meter case 2 having a flameproof structure as a field-type meter 1 of this type. To briefly explain this, an opening 4 covered with a glass window 3 is provided in a part of the instrument case 2. Reference numeral 5 is a sealing material that is interposed between the inner wall portion of the case 2 and the glass window 3 to seal the joint portion.

Reference numeral 6 is provided with a display device, such as a liquid crystal display device, which is internally provided in the instrument case 2 close to the inside of the glass window 3. Therefore, since such a display device 6 can be visually observed from the outside through the glass window 3 and the display information can be confirmed at the installation site, the effect as a field instrument can be exhibited.

Here, reference numeral 7 in the drawing amplifies and arithmetically processes a measurement signal or the like from a measuring unit of the electromagnetic flow meter, which is provided inside the meter case 2 and whose detailed illustration is omitted, and transmits it to an external indicator meter. In addition, it is an electric circuit section including various electric parts and electronic parts for displaying the measured values and the like on the display device 6 described above.

Further, reference numeral 8 is a neck portion for connecting the measuring instrument case 2 constituting the transmitting portion case portion to the measuring portion of the electromagnetic flowmeter described above.

Reference numeral 9 in the drawing indicates that disturbance noise from the outside of the case, which is provided on the rear surface side of the display device 6 in the instrument case 2 through the glass window 3, adversely affects the electric circuit section 7. It is a shield plate having a shield function for preventing.

[0009]

[Problems to be solved by the device]

 However, in the field instrument 1 as described above, the shield plate 9 for shielding the influence of the disturbance noise from the glass window 3 on the electric circuit portion 8 has the following problems.

That is, in the case of providing such a shield plate 9 in the instrument case 2 so as to define the display device 6 and the electric circuit portion 8 in the simplest manner, for example, the case 2 which is divided into two is divided into two. A shield plate is sandwiched and held between the constituent members when they are integrated. However, in such a structure, a wasteful space is generated in the back side portion of the display device 6 in the case 2. However, it is not possible to make effective use of space.

Therefore, like the shield plate 9 in FIG. 2 described above, a member provided at the mounting portion of the display device 6 in the case 2 so as to also surround the mounting member of the display device 6 is provided. It is considered to be attached to the inner wall of the case 2. However, in such a structure, the structure in which the lead 6a of the display device 6 penetrates the shield plate 9 is likely to be complicated, resulting in high cost, and further, the liquid crystal display device itself used as the display device 6 has the above-mentioned disturbance noise. It was affected and caused problems such as malfunctions.

The present invention has been made to eliminate such problems, and can easily and reliably shield the disturbance noise from the glass window of the instrument case, prevent its adverse effects, and have a simple structure. The aim is to obtain a field instrument that is cheap in terms of cost.

[0013]

[Means for Solving the Problems]

 In order to meet such a demand, the field instrument according to the present invention covers the opening formed in a part of the instrument case and extends along the glass surface of the glass window in which the display device is arranged close to the inside. The transparent conductive film is provided in series.

[0014]

[Action]

 According to the present invention, since the transparent conductive film is connected along the glass surface to be the glass window, the display by the display device can be seen from the outside and the disturbance from the glass window to the inside of the case can be achieved. Noise can be prevented by the shielding function of the transparent conductive film that is body-grounded on the case side.

[0015]

【Example】

 FIG. 1 shows an embodiment of a field instrument according to the present invention, in which the same or corresponding parts as those in FIGS. 2 and 3 described above are designated by the same reference numerals and detailed description thereof will be omitted.

Now, according to the present invention, along the glass surface of the glass window 3 that covers the opening 4 formed in a part of the instrument case 2 and the liquid crystal display device 6 is arranged close to from the inside. It is characterized in that the transparent conductive film 10 is provided in series.

Here, such a transparent conductive film 10 is formed on the back surface of the glass window 3 by a thick film or a thin film by vapor deposition or the like, for example, by a transparent conductive material such as ITO or SnO 2. Alternatively, it may be formed as a plate-like body having a predetermined thickness, and the plate-like body may be provided between the glass window 3 and the liquid crystal display device 6.

Further, such a transparent conductive film 10 is connected to the case 2 by a ground 11 and is body-grounded so as to have the same potential.

According to such a configuration, the transparent conductive film 10 provided so as to be connected along the glass surface that becomes the glass window 3 makes it possible to visually display the liquid crystal display device 6 from the outside and also to display the glass. Disturbance of disturbance noise from the window 3 can be prevented over the entire surface of the glass window 3. Therefore, such a transparent conductive film 10 prevents disturbance noise from mixing into the case 2, and the noise is not only applied to the liquid crystal display device 6 but also to the electric circuit section 8 and the like disposed inside the case 2. It is possible to easily and surely shield the glass window 3 from adverse effects, and the structure is simple and the cost is low.

It is needless to say that the present invention is not limited to the structure of the above-described embodiment, and the shape, structure, etc. of each part can be appropriately modified and changed. For example, the shape of the instrument case 2 and the glass window 3, the structure for attaching the transparent conductive film 10 to the glass window 3, the body ground structure for the case 2, the attachment structure for the display device 6 such as a liquid crystal display device, and the like are various. Modifications are possible.

Further, the present invention is not limited to the case of the transmitter of the electromagnetic flowmeter according to the above-described embodiment, but may be a field type instrument having a glass window provided so that the display device can be seen from the outside. Of course, it can be applied to a measuring device to exert the effect.

[0022]

[Effect of device]

 As described above, according to the field instrument according to the present invention, along the glass surface of the glass window that covers the opening formed in a part of the instrument case and the display device is arranged close to the inside. Since the transparent conductive film is provided so as to be connected, the display by the display device can be externally displayed by the transparent conductive film that is connected along the glass surface to be the glass window, despite the simple and inexpensive structure. The transparent conductive film in the glass window makes it easy to see and prevent disturbance noise from entering through the glass window, and to affect the display device and the electric circuits inside the case. It also has a practically excellent effect of being able to reliably shield.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing an embodiment of a field instrument according to the present invention in an enlarged manner, showing only a glass window and a display device attachment part.

FIG. 2 is a sectional view of a main part of a conventional field instrument.

FIG. 3 is a schematic view showing a display window portion in a conventional field instrument.

[Explanation of symbols]

 1 Field-type instrument 2 Instrument case 3 Glass window 4 Opening 5 Sealing material 6 Display device 6a Lead 7 Electric circuit part 10 Transparent conductive film 11 Earth

Claims (1)

[Scope of utility model registration request] 1. A field instrument in which a glass window is provided in an opening formed in a part of a case, and a display device is arranged close to the glass window, wherein a transparent conductive material is provided along a glass surface of the glass window. A field instrument that is characterized by connecting membranes.