JP2001134196A - Protective cover for liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a protective cover for a liquid crystal display device which has high strength and makes it easier to see accurately the displayed contents of the liquid crystal device. SOLUTION: This protective cover for a liquid crystal display device is integrally provided with a sheet-like reinforcing part 3 consisting of transparent resin material having the strength higher than the transparent resin material constituting a main body part 2 on the front side of the main body part 2 consisting of transparent resin material which is excellent in optical homogeneity. For example, the main body part 2 is molded with acrylic resin and the reinforcing part 3 is formed with polycarbonate resin of the thickness of 0.2 mm-1.0 mm. The main body part 2 and the reinforcing part 3 are integrated into one body by means of insert molding, adhesion or the like. One part of the main body part 2 can be coated with light-shielding coating material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a protective cover disposed on a front surface of a liquid crystal display device, and more particularly to a structure of a protective cover suitable for a liquid crystal display device mounted on a vehicle.

[0002]

2. Description of the Related Art A dashboard of an automobile is provided with a liquid crystal display device for displaying, for example, an operating state of an air conditioner. The liquid crystal display device is provided on the front of the liquid crystal display device with mechanical shock or the like. A protective cover for protection is provided.

[0003] Conventionally, as this kind of protective cover,
Because of high transparency and optical homogeneity, the display contents of the liquid crystal display device are easily visible, and the molding is easy and the mass productivity is excellent. .

[0004]

However, a molded article of an acrylic resin has a disadvantage that it is susceptible to a mechanical impact force, and furthermore, has a drawback in that when it is broken, the broken portion has a sharp edge shape. It is hoped that the shift to a new one will take place.

[0005] In order to cope with such a technical demand, the present applicant has made a protective cover of a liquid crystal display device using a polycarbonate resin which is more resistant to mechanical impact than an acrylic resin. And a sufficient effect on impact strength was obtained. In addition, the protective cover made of the polycarbonate resin is advantageous in terms of safety because the broken portion becomes spherical.

However, a molded article of a polycarbonate resin generates a large residual stress due to non-uniform molecular orientation at the time of molding and becomes an optically anisotropic substance, which causes birefringence in incident light. It has been found that when used as a protective cover, there is a problem that the display content of the liquid crystal display device is double-viewed and difficult to visually recognize. In addition, since it is an optically anisotropic body, when viewed through polarized sunglasses, stress fringes generated on the protective cover are visually recognized, and in the worst case, the display content of the liquid crystal display device cannot be visually recognized at all. I also found out. When driving a car, the driver often wears polarized sunglasses for anti-glare purposes. Therefore, the above-mentioned inconvenience is particularly problematic with respect to a protective cover disposed on the front of a vehicle-mounted liquid crystal display device.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned deficiencies of the prior art, and it is an object of the present invention to provide a protective cover for a liquid crystal display device having a high strength so that the display contents of the liquid crystal display device can be easily viewed. To provide.

[0008]

In order to achieve the above object, the present invention provides a protective cover for a liquid crystal display device on a front surface of a main body made of a transparent resin material having excellent optical homogeneity. The sheet-shaped reinforcing portion made of a transparent resin material having higher strength than the transparent resin material forming the portion is integrally provided.

As described above, when the sheet-shaped reinforcing portion made of a transparent resin material having higher strength than the transparent resin material constituting the main body portion is integrally provided on the front surface of the main body portion made of the transparent resin material, Is reinforced by the reinforcing portion, so that the strength of the protective cover can be increased as a whole. The reinforcing portion may be made of a resin material having a small birefringence such as an acrylic resin, or may be made of a resin material having a large birefringence such as a polycarbonate resin. Even when the reinforcing portion is made of a resin material having a large birefringence, the displacement of the image due to the birefringence is small because the thickness of the reinforcing portion is smaller than that of the main body, and the visibility of the display content of the liquid crystal display device is reduced. Can be improved. The image shift due to birefringence is caused by a specific angle between the direction of the linearly polarized light incident on the protective cover from the liquid crystal display device and the direction of the main refractive index axis of the protective cover, that is, 0 °, 45 ° or 90 °.
°, the sheet-like reinforcing portion can align the direction of the main refractive index axis in a specific direction, and thus the direction of the linearly polarized light and the direction of the main refractive index axis. It is possible to easily and accurately adjust the relative angle with respect to the liquid crystal display device, and also from this point, the visibility of the display content of the liquid crystal display device is improved. Further, since the thickness of the reinforcing portion is small and the main refractive index axis of the protective cover can be aligned in a specific direction, stress fringes are hardly visually recognized even when viewing the liquid crystal display device through polarized sunglasses. The display contents of the device can be visually recognized.

Specifically, the main body is preferably formed of an acrylic resin because of its high optical homogeneity and transparency, and good molding and excellent mass productivity. From the viewpoint of high strength and high transparency, it is preferable to mold with a polycarbonate resin.

In addition, a required portion of the main body and / or the reinforcing portion may be coated with a light-shielding coating for preventing light leakage from unnecessary portions. In this way, the protective cover with the light-shielding paint applied to the required parts is unnecessary,
For example, since light leakage from the peripheral edge portion of the protective cover and the side surface of the main body portion is prevented, the display contents of the liquid crystal display device can be more clearly recognized.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a protective cover according to the present invention will be described below with reference to FIGS. 1 is a side view of the protective cover according to the embodiment with the mask and coating removed, FIG. 2 is an enlarged cross-sectional view of the portion 2-2 in FIG. 1, showing the mask and coating, and FIG. FIG. 4 is a plan view of a protective cover according to an embodiment, FIG. 4 is an explanatory view showing a method of manufacturing the protective cover, FIG. 5 is an explanatory view showing a method of coating the protective cover, and FIG. 6 is a liquid crystal provided with the protective cover according to the embodiment. It is principal part sectional drawing which shows the attachment state to the dashboard of a display device.

As apparent from FIGS. 1 to 3, the protective cover 1 of the present embodiment mainly includes a main body 2 formed of a transparent resin material having excellent optical homogeneity,
And a sheet-like reinforcing portion 3 formed of a transparent resin material having a strength higher than that of the transparent resin material, and the main body portion 2 has a thick lens portion 2a and the lens portion 2a. And a thin flange portion 2b formed around the periphery. Acrylic resin is particularly preferable as the transparent resin material constituting the main body 2 because of its high transparency, excellent optical homogeneity, easy molding, and excellent mass production, and the like. As the transparent resin material to be used, a polycarbonate resin is particularly preferable because of its high transparency and excellent mechanical strength such as impact resistance. The lens part 2a has a thickness of 4 mm to 6 m.
m, and the reinforcing portion 3 has a thickness of 0.2 mm.
To 1.0 mm. The reinforcing portion 3 can be manufactured by injection molding, or can be manufactured by punching or the like from a large resin sheet manufactured by extrusion or the like. The main body 2 and the reinforcing part 3 are integrally formed by insert molding or bonding. When the protective cover 1 composed of the main body 2 and the reinforcing portion 3 is formed by insert molding, it is preferable to perform an annealing process for removing distortion after molding.

When the reinforcing portion 3 is made of an optically anisotropic body such as a polycarbonate resin, there is a problem of deterioration of visibility of display contents due to birefringence. As shown in FIG. 3, the deterioration of the visibility is caused by the liquid crystal display device 11.
The angle θ between the direction of the linearly polarized light A incident on the protective cover 1 from the direction shown in FIG. 6 and the direction of the main refractive index axis B of the reinforcing portion 3 as an optically anisotropic body is 0 °, 45 ° or 90 °. Therefore, when manufacturing the reinforcing portion 3 made of this kind of resin material, the main refractive index axis is adjusted so as to be aligned in a predetermined direction. That is, when the reinforcing portion 3 is manufactured by injection molding, the position of the gate, the resin temperature, the resin temperature, and the like are set so that the main refractive index axis B is formed in the length direction or the width direction of the reinforcing portion 3 or in a direction at 45 degrees to the direction. The injection speed, the temperature control of the molding die and the like are adjusted. Also, the reinforcing part 3
In the case of manufacturing by extrusion molding, as shown in FIG. 4, the direction of the main refractive index axis B of the extruded resin sheet 6 which is the basis of the reinforcing portion 3 is measured, and the length direction of the reinforcing portion 3 is measured. Alternatively, the reinforcing portion 3 is stamped and formed so that the main refractive index axis B is oriented in the width direction or a direction forming 45 degrees with the width direction.

In FIGS. 2 and 5, reference numeral 4 denotes a light-shielding paint, and reference numeral 5 denotes a light-shielding mask for preventing adhesion of the coating paint to unnecessary portions. As is clear from these figures, the mask 5 is formed on the edge portion extending from the outer periphery of the surface of the reinforcing portion 3 to the side surface of the lens portion 2a, and the coating 4 is formed on the portion extending from the side surface of the lens portion 2a to the upper surface of the flange portion 2b. It is formed. The coating 4 is shown in FIGS.
It can be performed by the procedure of (c). That is, first, FIG.
As shown in (a), a first mask 5a is formed on the outer periphery of the reinforcing portion 3 and the outer periphery of the surface of the lens portion 2a by silk screen printing or the like. Next, as shown in FIG. 5B, a second mask 5 is provided on the upper side surface of the lens portion 2a.
b is formed by tampo printing or the like. Further, FIG.
As shown in (c), a masking 7 is applied to a portion extending from the light transmitting portion of the reinforcing portion 3 to the second mask 5b with an adhesive tape or the like, and a light-shielding coating 4 is applied to a required portion in this state. If the masking 7 is peeled off after the coating, the required protective cover shown in FIG. 2 is obtained.

As shown in FIG. 6, the protective cover 1 according to the present invention is fixed to the protective cover setting portion 15 formed on the dashboard 14 via the double-sided adhesive tape 8 attached to the back surface of the flange portion 5b. Is done. In FIG. 6,
Reference numeral 11 denotes a liquid crystal display device, reference numeral 12 denotes a wiring board, reference numeral 1
Reference numeral 3 denotes a lead wire for electrically connecting the liquid crystal display device 11 and the wiring board 12.

As described above, the protective cover 1 of the liquid crystal display device according to the present embodiment comprises the main body 2 made of a transparent resin material.
Is integrally provided with a sheet-like reinforcing portion 3 made of a transparent resin material having a higher strength than the transparent resin material constituting the main body portion 2, so that the main body portion 2 is reinforced by the reinforcing portion 3, and as a whole, The strength of the protective cover 1 can be increased. Further, in the protective cover 1 of the liquid crystal display device according to the present embodiment, since the reinforcing portion 3 is formed in a sheet shape,
Even when the reinforcing portion 3 is made of a resin material having a large birefringence, the image shift due to the birefringence can be reduced, and high visibility can be secured. In addition, since the direction of the linearly polarized light incident on the protective cover 1 from the liquid crystal display device and the direction of the main refractive index axis of the protective cover 1 are adjusted, when the reinforcing portion 3 is made of a resin material having a large birefringence, this point is considered. Thus, high visibility can be ensured.
Furthermore, since the thickness of the reinforcing portion 3 is small and the main refractive index axis of the protective cover 1 is aligned in a specific direction, stress fringes are hardly visually recognized even when viewing the liquid crystal display device 11 through polarized sunglasses. The display contents of the liquid crystal display device 11 can be visually recognized with certainty.

Further, the protective cover 1 of the liquid crystal display device according to this embodiment comprises a lens portion 2a from the outer periphery of the surface of the reinforcing portion 3.
The light-shielding mask 5 is applied to the edge portion extending over the side surface of the lens cover 2 and the light-shielding paint 4 is applied to the portion extending from the side surface of the lens portion 2a to the upper surface of the flange portion 2b. Of the liquid crystal display device 11 can be visually recognized more clearly. Further, when the light-shielding paint 4 is applied, since a light-shielding mask 5 is formed by printing on a required portion as a pre-processing, the disturbance of the edge of the paint 4 caused when the masking 7 is peeled off causes It does not appear in the light transmitting part and is excellent in aesthetic appearance.

In the above embodiment, the main body 2 is formed of an acrylic resin and the reinforcing portion 3 is formed of a polycarbonate resin. However, the gist of the present invention is not limited to this. The protective cover of the liquid crystal display device according to the present invention can be formed with a combination of any transparent resin materials belonging to the present invention.

[0020]

According to the first aspect of the present invention, a sheet-like reinforcing portion made of a transparent resin material having higher strength than the transparent resin material constituting the main body portion is provided on the front surface of the main body portion made of the transparent resin material. Since it is provided integrally, the main body is reinforced by the reinforcing portion, and the strength of the protective cover can be increased as a whole. According to the first aspect of the present invention, since the reinforcing portion is formed in a sheet shape, even when the reinforcing portion is made of a resin material having a large birefringence, an image shift due to birefringence can be reduced. , High visibility can be secured.

According to a second aspect of the present invention, the main body is formed of an acrylic resin having high optical homogeneity and transparency, and is excellent in molding and excellent in mass productivity, and the reinforcing portion has high strength and high transparency. Since the protective cover is made of a polycarbonate resin, a protective cover having high strength and excellent optical characteristics can be manufactured at low cost.

According to the third aspect of the present invention, light-shielding coating is applied to a required portion of the main body and / or the reinforcing portion, so that light leakage from the peripheral edge of the protective cover and the side surface of the main body is prevented. Thus, the display content of the liquid crystal display device can be more clearly recognized.

[Brief description of the drawings]

FIG. 1 is a side view of a protective cover according to an embodiment with a mask and a coating removed.

FIG. 2 is an enlarged cross-sectional view of a portion 2-2 in FIG. 1, showing a mask and painting.

FIG. 3 is a plan view of a protective cover according to the embodiment.

FIG. 4 is an explanatory view showing a method of manufacturing a protective cover.

FIG. 5 is an explanatory view showing a method of coating a protective cover.

FIG. 6 is a cross-sectional view illustrating a state where the liquid crystal display device including the protective cover according to the embodiment is attached to a dashboard.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Protective cover 2 Body part 2a Lens part 2b Flange part 3 Reinforcement part 4 Light-shielding coating 5 Light-shielding mask 5a First mask 5b Second mask 11 Liquid crystal display device 14 Dashboard 15 Protective cover setting part

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yasushi Takeda 1-7 Yukitani Otsukacho, Ota-ku, Tokyo Alps Electric Co., Ltd. (72) Inventor Minoru Takahashi 1-7 Yukitani Otsukacho, Ota-ku, Tokyo Alp F-term (reference) in SU Electric Co., Ltd. 3L011 CS00 5G435 AA00 AA08 AA09 BB12 FF13 HH02 HH05

Claims (3)

[Claims] 1. A sheet-like reinforcing portion made of a transparent resin material having a higher strength than the transparent resin material forming the main body is integrally formed on the front surface of a main body made of a transparent resin material having excellent optical homogeneity. A protective cover for a liquid crystal display device, comprising: 2. The protective cover according to claim 1, wherein the main body is made of an acrylic resin, and the reinforcing part is made of a polycarbonate resin. 3. The protective cover according to claim 1, wherein a light-shielding paint is applied to a part of the main body.