Display device

Abstract

To provide a display device capable of precisely mounting a glass member to a casing.SOLUTION: A liquid crystal display device 100 includes a liquid crystal module 120 including cover glass 150 formed in a side of a display surface, and a casing 110 that includes a sidewall 112 for prescribing an opening P and a first stepped section 116 formed in an inner periphery of the sidewall, and houses the liquid crystal module 120 inside via the opening P, and a resin 160 for welding is provided between an outer periphery of a back side of the cover glass 150 and the first stepped section 116. The casing 110 is constituted of resin for absorbing infrared rays. The resin 160 for welding is constituted of a material for transmitting infrared rays, and a junction between the resin 160 for welding and the first stepped section is welded by an infrared laser applied from an upper section of the cover glass 150.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a display device, and particularly to the attachment of a cover glass for protecting the surface of a liquid crystal module housed in a housing.

Background Art

[0002] A liquid crystal display device includes a liquid crystal module housed in a housing, and the liquid crystal module is configured to include a liquid crystal panel and a cover glass attached to the surface thereof. For example, Patent Document 1 discloses a liquid crystal display device in which the back surface of a cover glass protruding outward from a liquid crystal panel is fixed to a first fixing portion of a frame with an adhesive, and the liquid crystal panel is fixed to a second fixing portion of the frame with an adhesive.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] FIG. 1(A) is a schematic plan view of a conventional liquid crystal display device, and FIG. 1(B) is a schematic enlarged view of a cross section taken along line A-A thereof. The liquid crystal display device 10 has a generally rectangular housing 20, and a liquid crystal module 30 and a backlight (not shown) are housed inside the housing 20. The liquid crystal module 30 includes, for example, a liquid crystal panel 40 including a liquid crystal panel, a TFT substrate, etc. between a pair of polarizing plates, a sheet metal member 50 that supports the back surface side of the liquid crystal panel 40, and a cover glass 60 that is adhered to the display surface side of the liquid crystal panel 40 via an optical adhesive. Further, a black printing portion 70 as a light shielding region is formed on the outer periphery of the back surface of the cover glass 60.

[0005] On one hand, the housing 20 includes a side wall 22 that defines an opening P for accommodating the liquid crystal module 30. A stepped portion 24 is formed on the inner periphery of the side wall 22. By adhering the outer periphery of the cover glass 60 protruding outward from the sheet metal member 50 and the stepped portion 24 with a double-sided tape or an adhesive 80, the cover glass 60 is attached within the opening P of the housing 20.

[0006] When attaching the cover glass 60, the positions of the cover glass 60 and the housing 20 are detected from the image data captured by a camera so that the gap Q between the inner surface of the side wall 22 defining the opening P and the side surface of the cover glass 60 becomes uniform, and the cover glass 60 is bonded by an automatic pasting facility.

[0007] However, the conventional method of attaching the cover glass has the following problems. (1) In the fixing method using the double-sided tape 80, after the cover glass 60 is bonded, due to the influence of the positioning accuracy by the camera and the accuracy of the outer contour of the cover glass 60 and the housing 20, when the gap Q becomes out of specification, it cannot be adjusted. Therefore, it is necessary to remove the cover glass 60 from the housing 20, and in the process, the cover glass 60 may be scratched or damaged, resulting in the rejection of the cover glass. (2) In the fixing method using an adhesive, after the cover glass 60 is bonded, it is possible to adjust the gap Q until the adhesive cures. However, it may take a long time until the adhesive cures, or the gap Q may change due to temperature changes during the curing process and the curing shrinkage of the adhesive, resulting in being out of specification. In this case as well, the cover glass must be rejected as a mounting defect. Therefore, a method of assembling the cover glass 60 and the housing 20 and fixing them in a state where the gap Q is uniformly adjusted is required.

[0008] The present invention solves such conventional problems, and an object thereof is to provide a display device and an attachment method capable of accurately attaching a glass member within an opening of a housing.

Means for Solving the Problems

[0009] The display device according to the present invention includes a display module including a glass member formed on the display surface side, a side wall defining an opening, and a stepped portion formed on the inner periphery of the side wall, and a housing that houses the display module therein through the opening, and a welding resin provided between the outer periphery on the back surface side of the glass member and the stepped portion, and the welding resin and the stepped portion are laser welded.

[0010] In one aspect, the housing is made of a material that absorbs infrared rays, a light-shielding portion is formed between the back surface of the glass member and the heat welding resin, the light-shielding portion and the welding resin are made of a material that transmits infrared rays, and by irradiating an infrared laser from above the glass member, the interface between the welding resin and the stepped portion is laser welded. In one aspect, the light-shielding portion is a black printed area formed on the back surface of the glass member, the stepped portion is continuously formed along the inner periphery of each side wall of the housing, the welding resin is a frame having an upper surface and a bottom surface, the upper surface is in contact with the light-shielding portion, and the bottom surface is in contact with the stepped portion. In one aspect, another stepped portion is formed above the stepped portion on the side wall, the outer periphery on the back surface side of the glass member is placed on the another stepped portion, and the welding resin is placed on the stepped portion. In one aspect, a gap is formed between the opening and the side surface of the glass member. In one aspect, the housing is made of a metal material, another welding resin is provided on the stepped portion to provide a placement surface, the welding resin is made of a material that transmits infrared rays, the another welding resin is made of a material that absorbs infrared rays, and by irradiating an infrared laser from above the glass member, the interface between the welding resin and the another welding resin is laser welded. In one aspect, a light-shielding portion is formed between the back surface of the glass member and the heat welding resin, the stepped portion is continuously formed along the inner periphery of each side wall of the housing, a plurality of the another welding resins are arranged spaced apart on the stepped portion, and a sealing material or an adhesive is filled in the space between the stepped portion and the welding resin.

[0011] A method of attaching a display module including a glass member formed on the display surface side to a housing according to the present invention is to provide a welding resin that transmits infrared rays on the outer periphery of the back surface side of the glass member, position the display module in the housing so that the welding resin contacts a stepped portion formed on the inner periphery of the side wall of the housing, irradiate laser light from above the glass member, and laser-weld the welding resin and the stepped portion.

Effect of the Invention

[0012] According to the present invention, a welding resin is provided between the outer periphery of the back surface side of the glass member and the stepped portion of the housing, and the welding resin and the stepped portion are laser-welded. Therefore, while ensuring the mounting position accuracy of the glass member, the glass member can be efficiently fixed to the housing. Thereby, it is possible to solve the problems of breakage of the glass member and curing time due to adhesive fixing that occurred in the conventional method.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0014] Embodiments of the present invention will be described. The present invention is applied to a display device that protects the surface of a display module with a cover glass. For example, it is applied to a liquid crystal display device that protects the surface of a liquid crystal module housed in a housing with a cover glass, a liquid crystal display device equipped with a touch panel function as a user interface, a liquid crystal display device equipped with a function of detecting the approach of a user's finger or the like using infrared rays, and the like.

Example

[0015] Next, embodiments of the present invention will be described with reference to the drawings. It should be noted that the scale of the drawings is exaggerated for easy understanding of the invention and does not necessarily represent the scale of an actual product.

[0016] FIG. 2(A) is a schematic plan view of a liquid crystal display device according to a first embodiment of the present invention, and FIG. 2(B) is a schematic cross-sectional view taken along line A-A. The liquid crystal display device 100 according to the present embodiment is configured to include a generally rectangular housing 110 and a liquid crystal module 120 housed in the housing 110. Although not shown here, a backlight is disposed below the liquid crystal module 120.

[0017] The housing 110 is made of a resin that absorbs infrared rays (IR), that is, a resin with a low transmittance of infrared lasers, and is made of, for example, ABS resin, ASA resin, PE resin, or the like. The housing 110 includes four side walls 112 and a bottom wall 114 connected to the four side walls 112. An opening P that is generally rectangular in plan view is defined by the four side walls 112 on the upper surface. The liquid crystal module 120 is housed inside the housing 110 through the opening P.

[0018] The liquid crystal module 120 includes, for example, a liquid crystal panel 130 including a liquid crystal panel and a TFT substrate between a pair of polarizing plates, a concave sheet metal member 140 that supports the back surface side of the liquid crystal panel 130, a cover glass 150 that is adhered to the display surface side of the liquid crystal panel 130 via an optical adhesive, and a welding resin 160.

[0019] The cover glass 150 is made of a material that transmits infrared rays and visible light. The planar shape of the cover glass 150 is generally rectangular according to the opening P, and the liquid crystal module 120 is mounted in the housing 110 so that the gap P between the side surface of the cover glass 150 and the side wall 112 of the housing 110 is uniform. The cover glass 150 protects the display surface of the liquid crystal module 120 and prevents foreign matter and the like from entering from the gap Q into the interior.

[0020] Also, on the outer periphery of the back surface of the cover glass 150, a black printing portion 170 with a certain width is formed as a light-shielding region. The black printing portion 170 is made of a material that transmits infrared rays, that is, a material with a high transmittance of infrared laser, and for example, IRX-HF ink (manufactured by Teikoku Ink Manufacturing Company) is used. By forming the black printing portion 170, when the liquid crystal display device 100 is viewed from above, a light-shielding region B is formed so as to surround the outer periphery of the rectangular display region W for displaying an image. When a touch panel is mounted on the liquid crystal display device, the display region W is also an area where touch operations are possible.

[0021] The upper end portion 142 of the sheet metal member 140 that supports the liquid crystal panel 130 is fixed to the black printing portion 170 by a double-sided tape 180. The double-sided tape 180 is further disposed between the side surface of the upper end portion 142 and the side surface of the welding resin 160, and the welding resin 160 is fixed so that the surface of the welding resin 160 contacts the black printing portion 170. Note that the upper surface of the welding resin 160 may be fixed to the black printing portion 170 with an adhesive.

[0022] The welding resin 160 is a frame body with a generally rectangular cross-section, and is fixed to the back surface of the black printing portion 170 along the black printing portion 170. The welding resin 160 is made of a material that transmits infrared rays, that is, a material with a high transmittance of infrared lasers, and is composed of, for example, SAN resin, PS resin, PC resin, PES resin, PP resin, etc. The cross-sectional shape of the welding resin 160 is not particularly limited to a rectangular shape, and may be, for example, a wedge-shaped cross-sectional shape. Also, the bottom surface of the welding resin 160 may be a flat surface, or may include some uneven portions or curved surface portions.

[0023] On the other hand, inside each of the four side walls 112 of the housing 110, a first stepped portion 116 including a placement surface for placing the welding resin 160 and a second stepped portion 118 including a placement surface for placing the end portion of the cover glass 150 outward above the first stepped portion 116 are formed.

[0024] The first stepped portion 116 is not particularly limited, but provides a flat plane for placing the welding resin 160, and the first stepped portion 116 is laser-welded to the placed welding resin 160. To facilitate laser welding, it is desirable that the interface between the first stepped portion 116 and the welding resin 160 is in close contact. Therefore, the flat bottom surface of the welding resin 160 is in close contact with the flat placement surface of the first stepped portion 116. However, if unevenness is formed on the bottom surface of the welding resin 160, the first stepped portion 116 can include unevenness that follows the unevenness of the welding resin 160. Also, the first stepped portion 116 may be colored with a black or gray pigment on the surface to effectively absorb infrared rays when irradiated with an infrared laser. Furthermore, the placement surface of the first stepped portion 116 may be smaller than the size of the bottom surface of the welding resin 160, or conversely, may be larger.

[0025] The height H from the placement surface of the first step portion 116 to the placement surface of the second placement portion 118 is approximately equal to the height of the welding resin 160. In a certain aspect, the height of the welding resin 160 is made larger than the height H, and when positioning the liquid crystal module 120 in the housing 110, pressure may be applied to the welding resin 160 in the height direction so that the bottom surface of the welding resin 160 is in close contact with the placement surface of the first step portion 116. In this case, a jig for pressing and positioning the liquid crystal module 120 in the housing 110 is used. The second step portion 118 is not particularly limited, but provides a flat surface for placing the black printing portion 170 at the outer edge of the back surface of the cover glass 150.

[0026] Next, a method for attaching the liquid crystal module to the housing will be described with reference to FIGS. 3 and 4. First, as shown in FIG. 3, a liquid crystal module 120 with a welding resin 160 fixed to the outer periphery of the back surface of a cover glass 150 protruding outward from a sheet metal member 140 is prepared, and the liquid crystal module 120 is incorporated into the housing through an opening P in the housing 110. At this time, the bottom surface of the welding resin 160 is placed on the placement surface of the first step portion 116, the outer edge of the cover glass 150 is placed on the placement surface of the second step portion 118, and the liquid crystal module 120 is positioned so that the gap Q between the side surface of the cover glass 150 and the opening P is uniform.

[0027] Next, with the gap Q adjusted uniformly, infrared laser light IR is irradiated from above the cover glass 150 to laser-weld the interface between the welding resin 160 and the first step portion 160. As shown in FIG. 4(A), while moving the laser device 200 along the outer periphery of the housing 110, infrared laser IR is irradiated toward the cover glass 160. At this time, the laser device 200 is positioned so that the infrared laser IR irradiates the welding resin 160.

[0028] This state is shown in Fig. 4(B). The infrared laser IR irradiated from the laser device 200 passes through the cover glass 150, the black printing portion 170, and the welding resin 160, and is absorbed by the first step portion 116 of the housing 110. Since the black printing portion 170 is made of a material that transmits infrared rays, it is prevented from being burned by the infrared laser IR. At the laser irradiation position, the first step portion 116 that absorbs infrared rays generates heat, and the resin at the interface or joint portion between the first step portion 116 and the welding resin 160 melts, and the two are mixed. After the laser irradiation stops, the cooled resin solidifies, and the welding resin 160 and the first step portion 116 are fixed.

[0029] Thus, according to this embodiment, with the liquid crystal module 120 positioned in the housing 110, the infrared laser IR is irradiated from the cover glass 150 side, and the welding resin 160 and the housing 110 are fixed by laser welding so as not to affect the appearance of the black printing portion 170. Therefore, the cover glass can be accurately attached to the housing so that the gap Q is uniform. As a result, problems such as the disposal of the cover glass due to poor attachment when using double-sided tape or an adhesive as in the prior art and the limitation of the curing time due to the fixing of the adhesive can be solved.

[0030] Next, a second embodiment of the present invention will be described. In the first embodiment, an example in which the housing is constituted by a resin that absorbs infrared rays was shown. In the second embodiment, an example in which a metal housing is used will be described.

[0031] Fig. 5(A) is a plan view of a liquid crystal display device according to a second embodiment of the present invention, and Fig. 5(B) is an enlarged sectional view taken along line A-A thereof. The same reference numerals are assigned to the same configurations as those in the first embodiment. The liquid crystal module 120 of the second embodiment is configured in the same manner as the liquid crystal module 120 of the first embodiment.

[0032] In the second embodiment, the housing 110A is made of a metal material, such as aluminum. A welding resin 300 is provided on the first step portion 116 of the side wall 112 of the housing 110A. The surface of the welding resin 300 provides a placement surface for the welding resin 160 on the liquid crystal module 120 side, and the joint surface between the welding resin 160 and the welding resin 300 is thermally welded by a laser.

[0033] The welding resin 300 is made of a material that absorbs infrared rays, that is, a material with a low infrared transmittance, and is made of, for example, ABS resin, ASA resin, PE resin, etc. The shape and size of the welding resin 300 are not particularly limited. For example, it has a shape with a surface that contacts the bottom surface of the welding resin 160 on the liquid crystal module 120 side, and for example, the cross-sectional shape is rectangular. The welding resin 300 can also be formed as a continuous frame along the first step portion 116. However, in this embodiment, as shown in FIG. 5(A), the welding resin 300 is provided at four locations on the first step portion 116. The attachment method of the welding resin 300 is not particularly limited. For example, the welding resin 300 can be embedded in a metal housing by insert molding, or fixed with an adhesive or the like.

[0034] In order to prevent the intrusion of dust and water, it is necessary to fix the entire circumference of the cover glass 150 and the housing 110A. However, due to the structural constraints of the metal housing 110A and the structural constraints of the liquid crystal module 120, if only a part of the welding resin 300 can be provided, an adhesive or a sealing member is used as a substitute. That is, as shown in FIG. 5(A), when a plurality of welding resins 300 are provided, the space where the welding resin 300 on the first step portion 116 does not exist, that is, the space other than the laser welding location, is filled with an adhesive to fix the welding resin 160 and the first step portion 116.

[0035] Figs. 6(A) and 6(B) show a method of attaching a liquid crystal module to a housing. As shown in Fig. 6(A), the liquid crystal module 120 is inserted into the housing 110A through the opening P of the housing 110A. The welding resin 160 is placed on the welding resin 300 that forms the first step portion 116. The outer edge of the cover glass 150 is placed on the second step portion 118. The position of the liquid crystal module 120 is adjusted so that the gap Q between the side surface of the cover glass 160 and the side wall 112 of the housing 110A is uniform.

[0036] After adjusting the gap Q, as shown in Fig. 6(B), in the same manner as in the first embodiment, four locations where the welding resin 300 exists are irradiated with infrared laser light from above the cover glass 150. The laser light passes through the cover glass 150, the black printing portion 170, and the welding resin 160 respectively, and is absorbed by the welding resin 300. Due to the absorption of the laser light, the temperature of the welding resin 300 rises. At the joint or joint surface between the welding resin 300 and the welding resin 160, the resin is thermally melted, and the two are mixed. After the laser irradiation, the cooled resin solidifies and is fixed. Since the cover glass 150 is temporarily fixed by the laser light IR, the liquid crystal display device can be passed to the next process without waiting for the curing of the adhesive.

[0037] Thus, according to the second embodiment, since the cover glass is fixed to the housing by infrared laser irradiation, the occurrence rate of out-of-spec gaps due to the conventional method of fixing with double-sided tape or adhesive can be significantly reduced. Furthermore, the curing time of the adhesive until the adhesive is cured (when the parts are temporarily fixed) by adhesive fixing can be significantly shortened.

[0038] In the above embodiment, an example of attaching a liquid crystal module to a housing is described. However, the present invention can be applied not only to liquid crystal display devices but also to display devices in which the surface of the housing is covered with a glass member.

[0039] As described above, the preferred embodiments of the present invention have been described in detail. However, the present invention is not limited to specific embodiments, and various modifications and changes are possible within the scope of the gist of the invention described in the claims.

Description of Symbols

[0040] 100, 100A: Liquid crystal display device 110: Housing 112: Side wall 116: First step portion 118: Second step portion 120: Liquid crystal module 150: Cover glass 160: Welding resin 170: Black printing portion 180: Double-sided tape 200: Laser device

Claims

1. A display module including a glass member formed on a display surface side; a housing including a side wall defining an opening and a step portion formed on an inner periphery of the side wall, the housing accommodating the display module therein through the opening; a welding resin provided between an outer periphery on the rear surface side of the glass member and the step portion, The welding resin and the step portion are laser welded to each other.

2. the housing is made of a material that absorbs infrared rays; a light-shielding portion is formed between the rear surface of the glass member and the thermal welding resin; the light-shielding portion and the welding resin are made of a material that transmits infrared rays, The display device according to claim 1 , wherein an interface between the welding resin and the step portion is laser welded by irradiating the glass member with an infrared laser from above.

3. the light blocking portion is a black printed area formed on the rear surface of the glass member, The step portion is formed continuously along the inner periphery of each side wall of the housing, The display device according to claim 2 , wherein the bonding resin is a frame having an upper surface and a bottom surface, the upper surface being in contact with the light blocking portion and the bottom surface being in contact with the step portion.

4. The side wall further has another step portion formed above the step portion, The display device according to claim 1 , wherein an outer periphery of the rear surface side of the glass member is placed on the separate step portion, and the welding resin is placed on the step portion.

5. The display device according to claim 1 , wherein a gap is formed between the opening and a side surface of the glass member.

6. The housing is made of a metal material, and another welding resin is provided on the step portion to provide a mounting surface; the welding resin is made of a material that transmits infrared rays, and the other welding resin is made of a material that absorbs infrared rays; The display device according to claim 1 , wherein an interface between the welding resin and the another welding resin is laser welded by irradiating the glass member with an infrared laser from above.

7. a light-shielding portion is formed between the rear surface of the glass member and the thermal welding resin; The step portion is formed continuously along the inner periphery of each side wall of the housing, The second welding resin is disposed on the step portion at a distance from each other, The display device according to claim 6 , wherein a sealant or adhesive is filled into a space between the step portion and the welding resin.

8. A method for mounting a display module including a glass member formed on a display surface side to a housing, comprising the steps of: a welding resin that transmits infrared rays is provided on the outer periphery of the rear surface side of the glass member; positioning the display module in the housing such that the welding resin is in contact with a step portion formed on an inner periphery of a side wall of the housing; a laser beam is irradiated from above the glass member, and the welding resin and the step portion are laser-welded to each other.

Images