JP4693659B2 - display - Google Patents

Description

  The present invention relates to a display that is incorporated in a control panel or the like to display the operation status of various devices to be controlled and to perform operations for controlling the operations of the devices to be controlled.

  Some displays are called programmable displays (simply displays). This indicator is equipped with a display function that displays the operation status of the control target device and an operation function that controls the operation of the control target device. Is done. In particular, in recent years, this type of display has dramatically expanded its industrial application, and has been incorporated into sites such as places where the temperature of the environment changes rapidly and cold regions. .

  The outline of a conventional display device will be described with reference to FIG. 6. The display device 2 includes a display body 8 having a case structure that is divided into a front case 4 and a rear case 6. The front end of the front case 4 of the display main body 8 constitutes a front panel 10 that spreads outward in a rectangular frame shape (flange shape), and the front panel 10 is configured to have a rectangular opening as a display window 12. Yes.

  In the display 2, the display body 8 is fitted into the display mounting opening 13 of the control panel 11 (not shown) from the front, and the front panel 10 is engaged with the outer peripheral edge of the display mounting opening. It is designed to be attached and fixed to.

  A liquid crystal display unit 14 with a touch panel is accommodated in the display unit body 8 and a touch panel 16 of the liquid crystal display unit 14 is faced from the display window 12 of the front panel 10 to constitute an operation screen of the display unit 2. is doing.

  A rectangular protective sheet 18 that covers the touch panel 16 is bonded to the front panel 10. The user can selectively perform an operation input by touching the touch panel 16 via the protective sheet 18.

  The protective sheet 18 is for protecting the touch panel 16 so that dust, oil, water, etc. do not adhere to the touch panel 16 depending on the installation environment of the control panel 11, and this protective sheet 18 is proposed in Patent Document 1 and the like. .

  However, the protective sheet 18 is adhered to the front panel 10 so that wrinkles do not occur on the sheet surface covering the touch panel 16 due to the visibility of the operation screen, the operability of the touch panel 16, the appearance of the display device 2, and the like. Bonded with the agent 20.

  From the above, for the protective sheet 18, a highly flexible resin such as a PET (polyethylene terephthalate) resin is selected as a material suitable for the operability of the touch panel 16. Further, if the protective sheet 18 has a high rigidity by increasing the thickness of the sheet, the protective sheet 18 is inferior in operability, visibility, and the like. Therefore, the protective sheet 18 is formed thin and has increased flexibility, and the rigidity is extremely small.

  On the other hand, for the front panel 10, a resin material having relatively high rigidity, for example, ABS (acrylonitrile butadiene styrene) resin is selected in order to secure the shape of the display 2.

  However, since the linear expansion coefficient of the resin material for the panel is several times larger than the linear expansion coefficient of the resin material for the protective sheet selected above, the temperature of the installation environment of the display device 2 causes a change in the temperature of the front panel 10. As shown in FIG. 7, the heat shrinkage is larger than that of the protective sheet 18, and shrinkage wrinkles 22 are generated over the entire surface of the protective sheet 18, thereby reducing the visibility of the operation screen on the display window 12 of the front panel 10. There has been a problem in that the operability, the antiglare property, and the appearance of the product are reduced.

From the above, the generation of the shrinkage wrinkles 22 greatly impairs the commercial value of the display device 2, and a display device 2 that does not generate the shrinkage wrinkles 22 is desired.
JP 2002-304254 A

  Therefore, the problem to be solved by the present invention is to prevent shrinkage wrinkles on the protective sheet even when the temperature of the installation environment changes, to reduce the visibility of the operation screen, the operability of the touch panel, and the appearance. It is to improve the commercial value of the display by making it possible to suppress the deterioration of the property.

The display according to the present invention includes a resin front panel having a rectangular frame shape and a display window, a touch panel of a liquid crystal display unit provided facing the display window of the front panel from the back side, and the entire display window. A protective sheet made of resin attached to the front surface of the front panel so as to cover the front panel, and the front panel is an indicator having a larger linear expansion coefficient and higher rigidity than the protective sheet, and the front panel has a linear expansion coefficient of the protective sheet and A shrink-proof sheet made of a material having substantially the same rigidity and higher rigidity than the protective sheet is bonded with an adhesive, and the protective sheet is attached to the front panel with the shrink-proof sheet interposed therebetween.

  The shrink-proof sheet preferably has a rigidity substantially equal to or greater than that of the front panel.

  The adhesive is preferably an adhesive having stress relaxation properties.

  The adhesive includes a double-sided adhesive tape having adhesive layers on both sides. Examples of the material for the adhesive layer include silicone-based, acrylic-based adhesives, SIS-based, SBS-based, and natural rubber-based materials. Acrylic materials are preferred from the standpoint of durability and versatility of the adherend. An adhesive having excellent moisture resistance and sealing properties is also preferable.

  Examples of the resin that is a material of the front panel include ABS (acrylonitrile butadiene styrene), PPE (polyphenylene ether), PS (polystyrene), and PBT (polybutylene terephthalate). These are preferable because of their high adhesive strength with epoxy resins widely used as resin insulation materials.

  For the resin that is the material of the protective sheet, for example, PET excellent in stress relaxation and polyolefin resin are preferable.

  The material of the shrink-proof sheet may be metal or resin. Examples of the material of the shrink-proof sheet include irons such as stainless steel, metals such as nonmagnetic metals and nickel alloys, ceramics, aramid, glass epoxy, and carbon resin.

  The linear expansion coefficient that is almost equal to the linear expansion coefficient of the protective sheet is a line that does not cause shrinkage wrinkles in the protective sheet due to relative displacement of the anti-shrink sheet relative to the protective sheet due to thermal contraction even when both sheets are thermally contracted due to temperature change. Says expansion rate.

  In the present invention, since the linear expansion coefficients of the two sheets are substantially equal, even if the temperature of the installation environment is lowered to a low temperature, the thermal contraction amount of both sheets is substantially the same, and the large linear expansion coefficient of the front panel. Even if the amount of heat shrinkage of the front panel is larger than the amount of heat shrinkage of both the above sheets, the rigidity of the shrink-proof sheet is higher than the rigidity of the protective sheet, preferably, it is almost equal to or more than the rigidity of the front panel. The shrinkage displacement of the front panel is not easily transmitted to the protection sheet due to the rigidity of the shrinkage sheet, and the relative displacement between the front panel and the shrinkage sheet is absorbed by the adhesive layer of the adhesive between the front panel and the shrinkage sheet. . As a result, the generation of shrinkage wrinkles on the protective sheet can be suppressed.

Moreover , the fall of the visibility of a touchscreen operation screen, the operativity fall of a touchscreen, and the fall of an external appearance can be suppressed.

  A preferable aspect of the present invention is that the sheet shape of the shrink-proof sheet is a rectangular frame shape corresponding to the rectangular frame shape of the front panel. In this aspect, there is no relative displacement of the shrink-proof sheet itself, and the protective sheet can be securely attached to and supported by the front panel, and the occurrence of shrinkage wrinkles on the inner peripheral side of the protective sheet can be reliably suppressed.

  A preferred embodiment of the present invention is to configure the shrink-proof sheet in a rectangular frame shape by combining a plurality of sheet pieces. According to this aspect, in addition to being able to effectively suppress the occurrence of shrinkage wrinkles of the protective sheet at low temperatures, when the shrink-proof sheet is processed from the raw material sheet, it can be processed with a high yield, thereby reducing costs. It becomes effective.

  A preferred embodiment of the present invention is that the shrink-proof sheet is made of a nonmagnetic metal material or stainless steel. According to this aspect, the shrink-proof sheet has sufficient rigidity that can resist the heat shrinkage of the front panel, and the shrink-proof sheet does not have a possibility of adversely affecting the internal electronic components of the display unit. Thus, the protective sheet can be securely attached and supported.

  ADVANTAGE OF THE INVENTION According to this invention, it can suppress effectively that shrinkage wrinkles generate | occur | produce in the protective sheet which has covered the display window by the temperature change in the installation environment of a display.

  Hereinafter, a display according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. 1 is a perspective view of the display device according to the embodiment, FIG. 2 is an exploded perspective view of the display device, FIG. 3 is a partially cutaway side view of the display device, and FIG. 4 is a partially enlarged sectional view of FIG. It is a figure which expands and shows a part further within a dotted line circle. The display according to the embodiment has the same configuration as that of the conventional display except for the shrinkage sheet described later. Therefore, in FIG. 1 to FIG. 4, the parts corresponding to FIG. Details of such portions are omitted.

  In the display device 2 of the embodiment, a highly rigid resin material having a large linear expansion coefficient, such as ABS resin, is selected as the material of the front panel 10. As the material for the protective sheet 18, a flexible resin material such as PET resin having a linear expansion coefficient smaller than that of the material of the front panel 10 and having low rigidity is selected.

  In the above configuration, the shrink-proof sheet 30 that prevents the thermal contraction of the protective sheet 18 is interposed between the panel surface 10 a of the front panel 10 and the outer peripheral sheet surface 18 a of the protective sheet 18 via the adhesives 32 and 34. It is disguised. The panel surface 10 a of the front panel 10 and the shrink sheet 30 are bonded by an adhesive 32, and the shrink sheet 30 and the outer peripheral sheet surface 18 a of the protective sheet 18 are bonded by an adhesive 34. The adhesives 32 and 34 may be double-sided adhesive tape. These adhesives 32 and 34 have an adhesive layer.

  The shrink-proof sheet 30 is made of a material having a linear expansion coefficient substantially equal to that of the protective sheet 18 and higher in rigidity than the front panel 10, for example, stainless steel having a thickness of about 0.3 mm (for example, SUS304).

Here, the PET resin that is the material of the protective sheet 18 has a linear expansion coefficient of 1.5 × 10 ⁻⁵ [cm / cm / ° C.], whereas the stainless steel that is the material of the shrink-proof sheet 30 has its linear expansion coefficient. The expansion coefficient is 1.7 × 10 ⁻⁵ [cm / cm / ° C.], and the linear expansion coefficients of both are substantially equal. This linear expansion coefficient is smaller than the linear expansion coefficient 9.2 × 10 ⁻⁵ [cm / cm / ° C.] of the ABS resin that is the material of the front panel 10.

  Due to the relationship of the linear expansion coefficient, the protective sheet 18 and the shrink-proof sheet 30 have a small elongation with respect to temperature change. Moreover, the elongation with respect to the temperature change between the protective sheet 18 and the shrink-proof sheet 30 is substantially the same. On the other hand, the front panel 10 has a larger elongation change with respect to the temperature change than the protective sheet 18 and the shrink-proof sheet 30.

  Further, since the material of the shrink-proof sheet 30 is stainless steel, the rigidity of the shrink-proof sheet 30 is higher than the rigidity of the front panel 10 as compared with the ABS resin that is the material of the front panel 10.

  In the above, the temperature of the installation environment is lowered, and the front panel 10 is greatly heat-shrinked due to the difference in linear expansion coefficient than the protective sheet 18 and the shrink-proof sheet 30, and the thermal stress accompanying the heat-shrinkage difference from the front panel 10 to the shrink-proof sheet 30. Even if the shrinkage is applied, since the rigidity of the shrink-proof sheet 30 is larger than the rigidity of the front panel 10, the shrink-proof sheet 30 is not subject to deformation due to the thermal stress. Further, in this case, the adhesive 32 interposed between the shrink-proof sheet 30 and the front panel 10 acts to absorb relative displacement due to thermal contraction between the shrink-proof sheet 30 and the front panel 10.

  From the above, in the display device 2 according to the embodiment, even if the temperature of the installation environment is lowered, no shrinkage wrinkles occur in the protective sheet 18 as shown in the perspective view of FIG.

  The present invention can also be implemented in the following forms.

  As shown in FIG. 5, the occurrence of shrinkage wrinkles of the protective sheet 18 at low temperatures can be effectively suppressed also by configuring the shrink-proof sheet 30 with a plurality of shrink-proof sheet pieces 30a in the embodiment. be able to. According to this configuration, when the shrink-proof sheet 30 is processed from the raw material sheet, it can be processed with a higher yield than the case of punching into a hollow rectangular shape, which is effective for cost reduction.

The material of the shrink-proof sheet 30 may have a linear expansion coefficient that is substantially the same as that of the protective sheet 18 and has rigidity that can resist thermal contraction of the front panel 10. For example, the linear expansion coefficient is 2.3. × 10 ^-5 aluminum material [cm / cm / ° C.], linear iron expansion coefficient of 1.27 × 10 ^-5 [cm / cm / ° C.] or other hard resin material is available. However, non-magnetic materials are desirable in consideration of electrical influences. Note that the display device of the embodiment can also be applied to a display device equipped with a liquid crystal display unit that does not have touch panel specifications.

FIG. 1 is a perspective view of a display according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the display. FIG. 3 is a partially cutaway side view of the display. FIG. 4 is an enlarged cross-sectional view of a part of the display, with a part enlarged in a dotted circle. FIG. 5 is a perspective view of a display device according to another embodiment of the present invention. FIG. 6 is a perspective view of a conventional display. FIG. 7 is a diagram showing a state in which shrinkage wrinkles have occurred in a conventional display.

Explanation of symbols

2 Display 4 Front case 6 Rear case 8 Display body 10 Front panel 12 Opening (display window)
14 Liquid crystal display unit with touch panel 16 Touch panel 18 Protective sheet 20 Adhesive 22 Shrinkage collar 30 Shrink-proof sheets 32 and 34 Adhesive

Claims (4)

A resin-made front panel that has a rectangular frame shape and a display window, a touch panel of a liquid crystal display unit that faces the display window of the front panel from the back side, and is attached to the front of the front panel so as to cover the entire display window The front panel is a display device having a larger linear expansion coefficient and higher rigidity than the protective sheet, and the front panel has a linear expansion coefficient substantially equal to that of the protective sheet and higher than that of the protective sheet. A display device characterized in that a shrink-proof sheet made of a material having high rigidity is bonded with an adhesive, and a protective sheet is attached to the front panel with the shrink-proof sheet interposed therebetween.   The display device according to claim 1, wherein the shrink-proof sheet has a rigidity substantially equal to or higher than a rigidity of the front panel. The display according to claim 1 or 2 , wherein the shrink-proof sheet has a rectangular frame shape corresponding to the rectangular frame shape of the front panel. Display device according to any one of the constitute the shrink sheet a plurality of sheet pieces in a rectangular frame shape, claims 1, characterized in that 3.

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