JPH0720631U - Explosion-proof display device - Google Patents

Abstract

(57) [Summary] [Purpose] To enable operations such as setting input using a touch panel in a display device with a flameproof structure. [Structure] A flat cable 10 connected to a transparent electrode of a touch panel 7 attached to the outer surface of a container 2 having a flameproof structure, and a display 3 housed inside the container 2.
And are connected via the Zener barrier 11. The Zener barrier 11 is composed of a plurality of Zener diodes that connect each signal line of the touch panel 7 to the ground line of the power supply device 12 of the display 3. Due to the constant voltage effect of the Zener diode, the voltage applied to each signal line of the touch panel 7 is limited to the reference value or less, and the touch panel 7 is structured as an intrinsically safe structure.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a display device having a touch panel on its display surface, and more particularly to an explosion-proof display device used in a special atmosphere.

[0002]

[Prior art]

 Some display devices that display control information, etc., are equipped with a touch panel composed of transparent electrodes on the screen of the display in order to make it easy to check changes in the control state when inputting numerical values, etc. is there. In addition, display devices used in factories and laboratories may be used in a special atmosphere such as highly flammable gas. Some devices are housed in a pressure-proof explosion-proof container to prevent sparks generated by contact operations in the electrical circuit from affecting the outside.

[0003]

[Problems to be solved by the device]

 However, if the display device with the touch panel attached to the display surface is stored as it is in the container having the explosion-proof structure, the touch panel cannot be operated from outside the container. Also, when the touch panel is provided outside the container, the touch panel itself is an electric circuit and cannot be used in a hazardous area unless it has an explosion-proof structure. Furthermore, a dedicated inlet is required to electrically connect a touch panel provided outside the container to a device inside the container, and how to provide this inlet becomes a problem.

An object of the present invention is to provide a touch panel provided outside a container having a flameproof structure by providing a voltage / current limiting circuit on each of a plurality of signal lines that connect a control unit of a display and a touch panel. An object of the present invention is to provide an explosion-proof display device which has a circuit and enables operation of a touch panel in a hazardous area.

Further, by providing a signal line of a touch panel through a fixing portion of transparent tempered glass in a container having a pressure-proof and explosion-proof structure for accommodating a display device, an explosion-proof display device capable of eliminating a dedicated lead-in port is provided. To do.

[0006]

[Means for Solving the Problems]

 The invention described in claim 1 is a container having a pressure-resistant explosion-proof structure in which a display unit including a power supply unit and a control unit is housed inside, and one surface of the display unit facing the display surface is made of transparent tempered glass. And a touch panel provided on the outer surface of the transparent tempered glass of the container and electrically connected to the control unit of the display unit through a plurality of signal lines, and each of the plurality of signal lines and the control of the display unit. And a voltage / current limiting circuit connected to the unit.

According to a second aspect of the invention, the plurality of signal lines are passed through a fixing portion that fixes the periphery of the transparent tempered glass to the container.

[0008]

[Action]

 According to another aspect of the invention, an indicator including a power supply unit and a control unit is housed in a container having a flameproof structure, and the outer surface of transparent tempered glass forming one surface of the container having a flameproof structure. A touch panel is attached to. The touch panel is electrically connected to the control unit of the display in the container via a plurality of signal lines, and each of the plurality of signal lines is connected to the ground line of the power supply unit via a constant voltage diode. Therefore, the voltage and current supplied from the power supply to the touch panel is limited to the reference value or less by the voltage / current limiting circuit, and no sparks that cause ignition or explosion are generated.

According to the second aspect of the present invention, the signal line connecting the touch panel and the control unit of the display penetrates the fixing portion of the transparent tempered glass in the container. Since the transparent reinforced glass is fixed to the container so as to maintain the flameproof structure, the signal line passing through this fixed part also maintains the container's flameproof structure. Therefore, it is not necessary to provide a dedicated flameproof structure for opening the signal line from the outside to the inside of the container.

[0010]

【Example】

 FIG. 1 is a partially cutaway front view and a side sectional view of an explosion-proof display device according to an embodiment of the present invention. The explosion-proof display device 1 is configured by housing a display device 3 in a container 2 made of an aluminum alloy and having a pressure-proof explosion-proof structure. A transparent tempered glass 4 is fixed to the front surface of the container 2, and the display surface 3 a of the display 3 faces the transparent tempered glass 4. The container 2 is composed of a body 2a and a lid 2b, and the lid 2b located on the front side is openable and closable with respect to the body 2a by a hinge 5. The lid 2b closes the front surface of the main body 2a, and the lid 2b is fastened to the main body 2a by a plurality of hexagon socket head cap screws 6 to secure the explosion-proof property of the inside of the container 2.

A touch panel 7 is attached to the outer surface of the transparent tempered glass 4, and the stopper plate 8 presses the transparent tempered glass 4 toward the transparent tempered glass 4. Further, a connector kit 9 is provided above the transparent tempered glass 4 and the stopper plate 8. This connector kit 9 is used to connect a flat cable 10 that connects the touch panel 7 to the control unit of the display 3.

FIG. 2 is a block diagram of the explosion-proof display device. As an example, the touch panel 7 is configured by arranging 20 transparent electrodes in the X direction and 13 transparent electrodes in the Y direction, and a total of 33 signal lines are transmitted to the control unit 31 of the display 3 via the flat cable 10. It is connected. The Zener barrier 11 is provided on the connection line of this signal line. The Zener barrier 11 is composed of 33 Zener diodes for connecting each signal line to the ground line of the power supply unit 12 and a current limiting resistor.

That is, as shown in FIG. 3, in the container 2, the signal line 32 connected between the touch panel 7 and the control unit 31 via the resistor R and the fuse F is connected to the resistor R and the fuse F. It is grounded at the ground wire 33 via the Zener diode D between them.

The Zener diode D limits the voltage value applied to the touch panel 7 from the power supply section 12 by the signal line 32 to a reference value or less. Further, the resistor R limits the current value supplied from the power supply unit 12 to the touch panel 7 to the reference value or less. The Zener barrier 11 is configured by arranging a Zener diode D corresponding to each signal line and a resistor R for limiting current in parallel.

FIG. 4 is an enlarged cross-sectional view of a side surface of a main part of the explosion-proof display device. 1A shows a cross section taken along line MM in FIG. 1A, and FIG. 1B shows a cross section taken along line NN. A transparent tempered glass 4 is fixed to a lid 2b that constitutes the container 2 of the explosion-proof display device 1. The transparent tempered glass 4 is sandwiched between the inner surface of the lid body 2b and the pressing plate 42 via packing 41. The pressing plate 42 is fastened to the lid body 2b with a flat head screw 44. At this time, a gap is provided between the recess 45 of the lid body 2b and the outer periphery of the transparent tempered glass 4, and the gap is filled with a thermosetting resin 43 such as epoxy resin. The filling of the thermosetting resin 43 ensures a pressure-proof and explosion-proof structure between the lid body 2b and the transparent tempered glass 4.

A touch panel 7 is attached to the outer surface of the transparent tempered glass 4, and the lead wire 46 of the transparent electrode of the touch panel 7 is connected to the connector kit 9. The connector kit 9 connects the lead wire 46 to the flat cable 10. The flat cable 10 penetrates the thermosetting resin 43 from the lower surface of the connector kit 9 through the front side and the upper surface, and is drawn into the inside of the container 2. The filling of the thermosetting resin 43 into the gap between the recess 45 and the transparent tempered glass 4 is performed after the flat cable 10 is pulled into the inside of the lid 2b through this gap. Therefore, the thermosetting resin 43 is cured with the flat cable 10 penetrating, and the flat cable 10 is fixed with the thermosetting resin 43 in close contact with the surface thereof. With this configuration, when the touch panel 7 located outside the container 2 and the control unit 31 of the display 3 housed inside the container 2 are electrically connected, an opening provided with a packing having a flameproof structure. The front side of the lid body 2b can be simply configured without the need to provide the above, and the handling of the flat cable 10 does not become complicated.

[0017]

[Effect of device]

 According to the invention as set forth in claim 1, the touch panel attached to the outer surface of the transparent tempered glass facing the display surface of the display housed in the container of the explosion-proof structure has an intrinsically safe structure by a constant voltage diode. Therefore, there is an advantage that even in a dangerous place where an explosion-proof structure is required, operations such as setting input for the controlled object can be performed easily and accurately through the touch panel.

According to the second aspect of the invention, the signal line connecting the touch panel located outside the container and the display unit housed inside the container is penetrated through the fixing portion of the transparent tempered glass. , It is not necessary to provide an opening with a flameproof packing for connecting the touch panel, and the signal lines can be easily routed, and the outer surface of the container near the transparent tempered glass can be configured simply. It is also possible to realize cost reduction.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view and side sectional view of an explosion-proof display device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of the explosion-proof display device.

FIG. 3 is a circuit diagram showing a connection state between a touch panel and a display unit in the explosion-proof display device.

FIG. 4 is an enlarged cross-sectional view of a side surface of a main part of the explosion-proof display device.

[Explanation of symbols]

 1-Explosion-proof display device 2-Container 3-Display 4-Transparent tempered glass 7-Touch panel 10-Flat cable 11-Zener barrier (voltage / current limiting circuit) 43-Thermosetting resin

Claims (2)

[Scope of utility model registration request] 1. A container having a pressure-resistant explosion-proof structure in which a display unit including a power supply unit and a control unit is housed, and one surface of the display unit facing the display surface is made of transparent tempered glass, and a transparent container. Provided on the outer surface of the tempered glass,
A touch panel electrically connected to the control unit of the display through a plurality of signal lines, and a voltage provided in the container and connected between each of the plurality of signal lines and the control unit of the display. An explosion-proof display device comprising a current limiting circuit. 2. The explosion-proof display device according to claim 1, wherein the plurality of signal lines are passed through a fixing portion for fixing the periphery of the transparent tempered glass to the container.