JPH10100243A - Bezel filter assembly and its manufacture - Google Patents

Abstract

PURPOSE: To provide an integral bezel filter assembly for a touch screen input unit by rigidly coupling between bezel filters. CONSTITUTION: The bezel filter assembly 11 comprises a protective filter 12 formed of a substantially transparent material for visible light, and a bezel 10 formed of a transparent material for IR(infrared ray) without transparency to the visible light. The bezel 10 is formed to accommodate IR emitting and receiving elements. The filter 12 and the bezel 10 are integrally formed via a coupling part 16 of a complementary shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bezel filter assembly used for a touch screen input device (or touch panel) and a method of manufacturing the same.

[0002]

2. Description of the Related Art Touch screen input technology is being widely used as a means to facilitate manipulation of computer software. According to this technique, the operation only needs to be performed by touching the screen, there is no need to have any computer experience, and no complicated operation is required. The user simply touches the appropriate box or box on the screen when activating the desired function.

[0003] Since no keyboard or other external input device is required, input by touch can be performed quickly and can be operated under severe conditions. For example, touch screen input is suitable for complex medical instruments or diagnostic devices, such as patient monitoring devices and blood analyzers.
Touch screen input can also be used to determine the location of a shopping area, other information providing devices and the like, ATM devices,
It is also suitable for devices that provide information to the general public or are accessible to the general public, such as training and simulation devices. In addition, touch screen input, unlike keyboards, is resistant to dirt and corrosive materials,
Provided is a simple and effective input method of a device for diagnosis or repair of a vehicle or the like. For example, an automobile maintenance device having a touch screen input mechanism in a harsh environment of an automobile repair facility can be used for a battery inspection and a repair process of a technician by analysis by a host computer.

As the use of computer controls utilizing touch screen input as described above has increased, computer displays have been designed to protect the display and its image from foreign objects and environmental factors, such as oil slicks, dust, or liquids, which are handled by the user. It is necessary to provide a protective layer or a protective filter thereon. A protective filter formed on the touch screen functions to protect the underlying touch screen. Such a protective layer is an LC that is easily damaged by the force repeatedly applied to the touch screen.
Particularly important for D (liquid crystal device). In addition to protecting the touchscreen, the protective filter serves to enhance the resolution of the touchscreen as a special coating that prevents contamination of the touchscreen by oil films and the like. Since the purpose of the display is to provide clear text (character surfaces) or graphics that are easily identifiable, the protective filter must not reduce the sharpness of the display image.

[0005] Conventional IR (infrared) sensitive touch screen devices detect contact by a human finger or other tool with a grid of infrared beams. The touch screen device includes a touch frame having a bezel, a control circuit having firmware to receive data from the touch frame, and a software device that uses the input data to perform calculations and other repairs.

[0006] An IR-sensitive touch screen device (infrared matrix frame) is a sensor device that senses contact by infrared rays (IR). The LEDs (light-emitting diodes) that emit infrared rays are arranged in a line on each of two adjacent sides of the touch frame substantially corresponding to the image display frame, and a row of phototransistors is arranged on the side facing the LEDs. Placed in A bezel transparent to infrared rays is formed along the same direction of the touch frame. The bezel may be fixed to the display housing. This type of touch screen device does not require a protective layer such as a protective filter on the display due to its function. That is, the main advantage of the IR-sensitive touch frame is that it does not degrade the display image. Therefore, in order to maintain the advantages of IR sensing, the protective filters used need to have good visible light transmission.

Many conventional computer monitors have a curved screen surface. According to the IR-sensitive touch screen device, if the screen is formed into a curved surface, it is difficult to accurately detect a touched position. Therefore IR
In a sensitive touch screen device, the protective filter has yet another function. That is, the protective filter functions as a flat finger stopper that blocks the infrared beam.

The above point is disclosed in the conventional example. US Patent No. 4,267,443
Issued as a patent on May 12, 1981 to Carroll et al.

[0009] As one method of providing a protective filter to a touch screen device, the protective filter may be formed integrally with the touch screen. The bezel surrounding the touch screen display is the structural connection point for the protective filter. One of the reasons that a flat type touch screen device is used is that it can be configured to be relatively small, so that the bezel filter assembly is preferably formed as small and light as possible. Therefore, when forming the protective filter and the bezel integrally, it is desirable not to increase the size of the boundary area.

A plastic protective filter having good visible light transmittance is suitable to be formed of a material transparent to visible light to have a uniform and flat thickness. However, these known methods are not suitable for forming shapes or colors suitable for, for example, protective filters and bezels surrounding displays. For example, when operating an IR-sensitive touch screen device, it is required that the bezel housing has a property of transmitting infrared rays and is difficult to transmit visible light. Accordingly, materials suitable as good protective filters, ie, those that are transparent or lightly colored, are not suitable as bezel assemblies.

In addition to the above restrictions, it is customary to shorten the time to market and reduce the risks associated with developing new products. Therefore, after determining the operation parameters of the device, it is necessary that the prototype manufactured in the later stage of development is also quickly performed.

[0012]

The integral formation of the protective filter and the bezel requires the use of expensive, unreliable and possibly harmful chemicals according to known methods. For example, the protective filter and the bezel may be glued together. However, this bonding method is unreliable when applied to a screen coated to reduce an oil film or the like and prevent scratches. The coating layer acts to weaken the bond and reduce the bond strength. Furthermore, the joint surface between the protective filter and the bezel is too small to ensure an effective surface for the adhesive to seal.

Adhesives based on solvents are also effective. However, the chemicals in the solvent are environmentally harmful. Another environmentally harmless bonding method is to use a solid pressure-sensitive adhesive tape. However, it is difficult to form a strong joint with such a tape in a small area.

[0014] Therefore, it has been desired to form the protective filter and the bezel of the touch screen efficiently, inexpensively, compactly and securely, and integrally form them.

[0015]

SUMMARY OF THE INVENTION The present invention provides a bezel filter assembly having a frame-shaped bezel and a plate-shaped protection filter made of a material transparent to visible light and mounted in the bezel. The bezel may be configured such that an inner edge of a frame and an outer edge of the protection filter are formed in a complementary shape to form a mechanical connection, and the bezel and the outer edge of the protection filter are integrally molded.

The present invention also provides a method for manufacturing a bezel filter assembly in which a plate-like protection filter is integrally mounted inside a frame-like bezel, wherein the protection filter and a preheated bezel forming material are molded into a mold. Disposing the bezel forming material to a temperature equal to or higher than the plasticizing temperature, depressurizing the interior of the mold and pressing the bezel forming material against a mold surface, and setting the bezel forming material to a plasticizing temperature. And a step of cooling to the following temperature.

According to the present invention, an apparatus in which a bezel of a touch screen and a protective filter are integrally formed and a method of manufacturing the same are disclosed. The present invention relates to a touch screen input device using an infrared (IR) beam.

In a preferred embodiment, the assembly comprises a polycarbonate or other transparent or colored plate having a suitable surface treatment, such as damage prevention, including a plate or protective filter cut to a suitable display size. . The plate is placed in a pressure formed mold and sealed with the preferred bezel material. The seal is preferably by a connection joining the bezel edge and the filter. The connection is usually a lock connection, a dovetail connection, a tongue-groove connection, a tenon
Mortise connection and the like are included. After molding, the excess sealing layer of bezel material is removed, excluding the end locking connection, exposing the protective filter surface. The end joint serves as a mechanical support and sealing means for the protective filter. Accordingly, an integrated structure of the protection filter and the bezel which is small and suitable for a touch screen input device is realized.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a bezel filter assembly and a method of manufacturing the same according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a bezel filter assembly 11 for a touch screen input device of the present invention. The bezel 10 is formed integrally with the filter 12 and the bezel filter assembly 11
Is configured. The bezel filter assembly 11 includes a lip 14 for receiving elements such as LEDs and phototransistors 18 for emitting and receiving infrared (IR) light, as shown in FIGS. In an IR-sensitive touch screen input device, the bezel 10 is formed to hold a circuit board 20, as shown in FIGS. However, this integral bezel filter assembly
The eleventh configuration is not only applicable to IR-sensitive touch screen input devices, but may also be applied to non-contact displays or other dissimilar material assemblies of protective or decorative covers for other purposes.

In the preferred embodiment of the present invention, a soft tooling method such as thermoforming is used. Thermoforming is a relatively inexpensive method in which a plastic plate is heated to a plastic state,
It is placed under the influence of air pressure to wrap the mold in the shape of the final product. This pressure forming step forms a plastic plate into a mold shape. In addition, by using a pressure higher than the atmospheric pressure as the specific molding pressure, it is possible to re-mold details and to deform the plastic plate into the shape in the mold.
Thermoforming by varying the air pressure is low cost and forms the bezel filter assembly 11 in the present invention.

The first step in the method of manufacturing the bezel filter assembly of the preferred embodiment of the present invention involves forming an appropriate space (blank) in the protective filter 12. Unlike conventional thermoforming methods, the method of the present invention does not heat the protective filter 12 to a plastic state. Therefore, the protective filter 12 does not shrink more than the bezel material 24 (see FIG. 4). The protective filter 12 is cut slightly larger than the desired final dimension of the display area, and preferably includes a border area 13 as shown in FIG. 3 to form a connection 16 with a complementary portion of the bezel 14.

A coupling scheme including a tongue-to-groove coupling is shown in FIGS. In the preferred embodiment shown in FIG. 2, the male part of the connection 16 is the boundary area 13 of the filter and the female part is the bezel material 10.
Is formed so as to surround the boundary area 13. This arrangement allows the bezel material 10 to shrink around the boundary of the filter during cooling
Allows you to fasten and fix 16. However, this coupling structure is an example. Another example is shown in FIG.
According to this, a tongue-and-groove structure is shown. The female part is a groove at the boundary area 13 of the protective filter, and the male part is a bezel material
Configured as a lip at 10. Various other modifications may be made by those skilled in the art.

The next step in the manufacturing method of the preferred embodiment of the present invention involves the form of a female cavity mold 22 having sufficient strength to withstand the pressure forming stress, as shown in FIG. The aluminum molds of the present invention can be formed by machining, but cast or other low cost molds can also be used.

FIG. 4 shows a molding process according to the present invention. Before the protective filter 12 is placed in the mold body 22, an insert of a soft material 26, such as a polyamide plate manufactured and sold by DuPont under the trademark NOMEX, is used on the inner surface of the mold to scratch the protective filter 12. And heat transfer during thermoforming.

On the other hand, a plate-like bezel material 24, preferably polycarbonate which is transparent to infrared radiation, is directly preheated by a radiant heater in preparation for the molding process. The mold 22 is located in the press thermoformer and preheats to a desired temperature corresponding to the bezel material. Approximately 138 ° C. is a suitable temperature for polycarbonate. Preheated bezel material 24
Is placed on the mold 22 in the frame, and the protective filter 12 is placed on the center plane of the mold body 22. Bezel material 24 is then heated to a plastic state. When the temperature starts to drop,
As shown in FIG. 4, the bezel material is lowered toward the mold 22, and then the mold 22 is evacuated. This allows atmospheric pressure to press the bezel material 24 against the mold 22. The box or chamber 28 is then
Pressure is applied to the bezel material 24 from the side opposite to the mold 22 to make contact with the surface of the mold 22, and the bezel material 24 is integrated with the boundary 13 of the protective filter 12,
The joint 16 is formed to form a sealed structure. Ie bezel material
The softened state of the plate 24 bonds the plate-shaped bezel material 24 to the boundary 13 of the protective filter 12.

Once the thermoforming process is completed, the bezel filter assembly 11 is cooled, preferably by an air tube or the like, in order to avoid deformation of the cooled protective filter, and immediately after the next thermoforming process. Can move on. Mold type
The protective NOMEX plate insert 26 in 22 acts to prevent thermal deformation of the protective filter 12. After the bezel material 24 has cooled below the plasticizing temperature, the internal pressure is returned to atmospheric pressure and the chamber 28 is raised. Thereafter, the bezel filter assembly 11 is removed from the mold 22 and the process of forming another assembly can be repeated.

The bezel filter assembly 11 can be trimmed, for example, by placing the assembly 11 on a fixture in a slicer to remove unwanted border and bezel material covering the center of the protective filter. Once the trimming is completed in the desired shape, the assembly is ready for use. Preferably, joint 16 may be reinforced by an adhesive or other adhesive, sealant.

Further modifications and alterations of the present invention can be made by those skilled in the art. The preferred embodiments described above are illustrative only and do not limit the invention.

[0030]

The integrated bezel filter assembly of the present invention is constructed so that the bezel and the protection filter are coupled in a complementary shape, so that the bezel and the protection filter are always robust even when using different materials. An integral connection is formed. At the same time, this connection provides a good seal.

Further, according to the method of manufacturing the integrated bezel filter assembly of the present invention, since the difference in air pressure is utilized, the appropriate bezel shape and the shape of the connecting portion can be formed at relatively low cost.

[Brief description of the drawings]

FIG. 1 is a perspective view of a portion of a housing of a touch screen input device according to a preferred embodiment of the present invention.

FIG. 2 is a sectional view taken along line 2-2 in FIG. 1;

FIG. 3 is a cross-sectional view similar to FIG. 2, showing another preferred embodiment of the present invention.

FIG. 4 is a sectional view showing a molding process of the touch screen input device of FIG. 1;

[Explanation of symbols]

 10 Bezel 11 Bezel filter assembly 12 Protective filter 16 Joint 22 Mold

Claims (2)

[Claims] 1. A bezel filter assembly comprising: a frame-shaped bezel; and a plate-shaped protection filter made of a material transparent to visible light and mounted in the bezel. A bezel filter assembly, wherein the outer edge of the protection filter is formed in a complementary shape to form a mechanical connection, and the bezel and the outer edge of the protection filter are integrally molded. 2. A method for manufacturing a bezel filter assembly in which a plate-shaped protection filter is integrally mounted inside a frame-shaped bezel, wherein the protection filter and a preheated bezel forming material are arranged in the mold. A step of heating the bezel forming material to a temperature equal to or higher than a plasticizing temperature; a step of depressurizing the interior of the mold and pressing the bezel forming material against a mold surface; A method of manufacturing a bezel filter assembly.