JP2020202057A - Reflection sheet, reflection sheet body, backlight device, and liquid crystal display device - Google Patents

Abstract

To provide a reflection sheet capable of preventing a light guide plate from moving on.SOLUTION: The present invention relates to a rectangular reflection sheet 10 which covers non-incidence side faces 43b to 43d and a reverse surface 43f of a light guide plate 43, and the light guide plate 43 comprises: a bottom face part 11 which abuts on the reverse face 43f; a plurality of side face parts 12 to 14 which connect with a plurality of sides, not opposed to a light source 42, of the bottom face part 11, and face the non-incidence side faces 43b to 43d of the light guide plate 43 when bent to the bottom face part 11; corner parts 15, 16 which connect the mutually adjacent side face parts 12, 13 and the side face parts 13, 14 to each other, and are bent to outside the side face parts 12 to 14 as the side face parts 12 to 14 are bent to the bottom face part 11; and perforations 10a to 10c which are made on border lines between the bottom face parts 11 and side face parts 12 to 14.SELECTED DRAWING: Figure 3

Description

The present invention relates to a reflective sheet, a reflective sheet body, a backlight device, and a liquid crystal display device.

In some backlight structures of liquid crystal display devices, a light guide plate is provided on the back surface side of the liquid crystal panel, and a light source is arranged so as to face the side surface of the light guide plate. In such a backlight structure, a reflective sheet is provided on the back surface of the light guide plate and surrounding the light guide plate. For example, Patent Document 1 discloses a liquid crystal display device including a reflective sheet.

Japanese Unexamined Patent Publication No. 2001-216827

In a conventional liquid crystal display device as disclosed in Patent Document 1, a bent portion of a reflective sheet is arranged around a light guide plate. Since the bending step of the reflective sheet is performed manually by, for example, an operator, the bending angle thereof varies. Therefore, when the bent portion is excessively bent, there is a problem that the light guide plate rides on the bent portion of the reflective sheet when the light guide plate is assembled. If the light guide plate rides on the bent portion of the reflective sheet, the light guide plate assembly work will have to be redone, and the work efficiency will decrease.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a reflective sheet capable of preventing the light guide plate from riding on.

The reflective sheet according to the present invention is a rectangular reflective sheet that covers the non-incident side surface and the back surface of a light guide plate having an incident side surface on which light emitted from a light source is incident and a non-incident side surface and a back surface other than the incident side surface. There are a plurality of bottom surfaces that are in contact with the back surface of the light guide plate and a plurality of sides of the bottom surface that are not opposed to the light source and are opposed to the non-incident side surface of the light guide plate when bent with respect to the bottom surface. Between the corner portion that connects the side surface portion and the side surface portions adjacent to each other and is bent toward the outside of the side surface portion as the side surface portion is bent with respect to the bottom surface portion, and between the bottom surface portion and the side surface portion. It is provided with a first perforation made on the boundary line of.

The reflective sheet according to the present invention is a rectangular reflective sheet that covers the non-incident side surface and the back surface of a light guide plate having an incident side surface on which light emitted from a light source is incident and a non-incident side surface and a back surface other than the incident side surface. There are a plurality of bottom surfaces that are in contact with the back surface of the light guide plate and a plurality of sides of the bottom surface that are not opposed to the light source and that face the non-incident side surface of the light guide plate when bent with respect to the bottom surface. Other than the third perforation formed on the side surface portion and the boundary line between the bottom surface portion and some of the side surface portions, and some side surface portions of the bottom surface portion and the plurality of side surface portions. It is provided with a fourth perforation that is parallel to the boundary line between the two side portions and the bottom surface portion of the boundary line.

According to the present invention, it is possible to prevent the light guide plate from riding on.

It is sectional drawing of the liquid crystal display device provided with the reflective sheet body which concerns on Embodiment 1. FIG. FIG. 1 is a cross-sectional view taken along the line AA of FIG. It is a figure which shows the reflection sheet which concerns on Embodiment 1. FIG. It is a perspective view of the reflective sheet body which concerns on Embodiment 1. FIG. It is sectional drawing which showed the state which the light guide plate rides on the reflective sheet body. 6A to 6C are views showing the chamfered shape of the corner portion. 7A to 7D are views showing perforated corners. It is a figure which shows the reflection sheet which concerns on Embodiment 2. It is sectional drawing which showed the assembly operation of the reflective sheet which concerns on Embodiment 2. FIG. It is sectional drawing which showed the other assembly operation of the reflective sheet which concerns on Embodiment 2. FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Embodiment 1.
The reflective sheet 10 according to the first embodiment will be described with reference to FIGS. 1 to 7.

First, the configuration of the liquid crystal display device 30 will be described with reference to FIGS. 1 and 2. FIG. 1 is a cross-sectional view of a liquid crystal display device 30 including the reflective sheet body 1 according to the first embodiment. FIG. 2 is a cross-sectional view taken along the line AA of FIG.

The liquid crystal display device 30 includes a liquid crystal panel 31 and a backlight device 32. The backlight device 32 is arranged on the back surface side of the liquid crystal panel 31 and supports the liquid crystal panel 31. In the liquid crystal display device 30, the liquid crystal panel 31 side is the front side and the backlight device 32 side is the rear side.

The backlight device 32 includes a reflective sheet body 1, a housing 41, a plurality of light sources 42, a light guide plate 43, a prism sheet 44, and a double-sided tape 45.

The housing 41 is made of sheet metal or resin. The housing 41 has a box shape with an opening on the front side. Further, the housing 41 holds the light source 42, the light guide plate 43, the prism sheet 44, and the reflective sheet body 1 inside, and supports the liquid crystal panel 31.

The light source 42 is, for example, an LED (light emitting diode) or a fluorescent tube. The light source 42 is provided on the inner surface of the housing 41. In the example of FIG. 2, the light source 42 is provided on one inner surface, but it may be provided on two inner surfaces. Further, although the number of light sources 42 installed is 5, any other number may be used.

The light guide plate 43 is made of, for example, an acrylic resin, and has a transmittance and a refractive index necessary for light transmission. The light guide plate 43 has an incident side surface 43a, a non-incident side surface 43b to 43d, an irradiation surface 43e, and a back surface 43f.

The incident side surface 43a faces the light source 42, and the non-incident side surfaces 43b to 43d do not face the light source 42. The irradiation surface 43e constitutes the front surface of the light guide plate 43 and faces the back surface side of the liquid crystal panel 31. The back surface 43f is attached to the bottom surface of the housing 41 via the reflective sheet body 1. The light guide plate 43 guides the light emitted from the light source 42 to the inside from the incident side surface 43a, and irradiates the light guided to the inside from the irradiation surface 43e toward the back surface of the liquid crystal panel 31.

The prism sheet 44 is made of, for example, a transparent resin. The prism sheet 44 is arranged so as to face the irradiation surface 43e of the light guide plate 43. When the light emitted from the irradiation surface 43e of the light guide plate 43 passes through the prism sheet 44, the passed light is uniformly diffused toward the back surface of the liquid crystal panel 31.

The reflective sheet body 1 is a light reflecting structure formed by bending the reflective sheet 10 described later from the unfolded state, and has a box shape such that the front side and the light source 42 side are opened. The reflective sheet body 1 may have a box shape so that only the front side is open. In this case, the light source 42 is provided on the inner surface of the housing 41 via the reflective sheet body 1.

The reflective sheet body 1 is attached to the bottom surface of the housing 41 via a double-sided tape 45. The reflective sheet body 1 may be assembled in place of the double-sided tape 45, or in addition to the double-sided tape 45, using an adhesive or the like.

The reflective sheet body 1 covers the non-incident side surfaces 43b to 43d and the back surface 43f of the light guide plate 43 from the outside. As a result, the reflective sheet body 1 plays a role of reflecting the light emitted from the non-incident side surfaces 43b to 43d and the back surface 43f of the light guide plate 43 and returning the light to the inside of the light guide plate 43 again.

Next, the reflective sheet body 1 and the reflective sheet 10 will be described with reference to FIGS. 3 to 7. FIG. 3 is a diagram showing a reflective sheet 10 according to the first embodiment. FIG. 4 is a perspective view of the reflective sheet body 1 according to the first embodiment. FIG. 5 is a cross-sectional view showing a state in which the light guide plate 43 rides on the reflective sheet body 1. 6A to 6C are views showing the chamfered shape of the corner portion 16. 7A to 7D are views showing the corner portion 16 provided with the perforation 10d.

The reflective sheet 10 shown in FIG. 3 is a sheet having a predetermined reflectance. The material of the reflective sheet 10 is, for example, polyethylene terephthalate (PET) resin. The reflective sheet 10 has a rectangular shape, and has a bottom surface portion 11, side surface portions 12 to 14, corner portions 15, 16, and perforations 10a to 10c. The perforations 10a to 10c constitute the first perforation.

The bottom surface portion 11 forms the bottom surface of the reflective sheet body 1 when the reflective sheet 10 is bent. The front surface of the bottom surface 11 is in contact with the back surface 43f of the light guide plate 43, and the rear surface is attached to the bottom surface of the housing 41 with double-sided tape 45.

The side surface portions 12 to 14 are connected to three sides of the bottom surface portion 11 that do not face the light source 42, respectively. When the side surface portions 12 to 14 are bent with respect to the bottom surface portion 11, the side surface portions 12 to 14 form three inner side surfaces of the reflective sheet body 1 and form the non-incident side surfaces 43b to the light guide plate 43. It faces each of 43d. As a result, the side surface portions 12 to 14 can reflect the light emitted from the non-incident side surfaces 43b to 43d and the back surface 43f of the light guide plate 43 and return the light to the inside of the light guide plate 43 again.

The corner portion 15 connects the side surface portion 12 and the side surface portion 13. The corner portion 16 connects the side surface portion 13 and the side surface portion 14. The corner portions 15 and 16 are located on the side of the reflective sheet 10 that does not face the light source 42, and form the corner portions of the reflective sheet 10. The corner portions 15 and 16 are bent toward the outside of the side surface portions 12 to 14 around the diagonal lines 15a and 16a as the side surface portions 12 to 14 are bent with respect to the bottom surface portion 11. Further, as shown in FIG. 2, when the reflective sheet body 1 is assembled to the housing 41, the bent corner portions 15 and 16 are inserted into the cutout portion 41a of the housing 41.

The perforation 10a is provided on the boundary line between the bottom surface portion 11 and the side surface portion 12. The perforation 10a is for making the side surface portion 12 easier to break with respect to the bottom surface portion 11. The perforation 10b is provided on the boundary line between the bottom surface portion 11 and the side surface portion 13. The perforation 10b is for making the side surface portion 13 easily broken with respect to the bottom surface portion 11. The perforation 10c is provided on the boundary line between the bottom surface portion 11 and the side surface portion 14. The perforation 10c is for making the side surface portion 14 easier to break with respect to the bottom surface portion 11.

As shown in FIG. 4, the reflective sheet body 1 is formed by bending the side surface portions 12 to 14 along the perforations 10a to 10c in the reflective sheet 10. Then, the reflective sheet body 1 is assembled in the housing 41 in a bent state.

At this time, the corner portions 15 and 16 are bent toward the outside of the side surface portions 12 to 14 as the side surface portions 12 to 14 are bent with respect to the bottom surface portion 11. A repulsive force that tries to return to the original flat plate state acts on the corner portions 15 and 16 that are bent in this way. Since the side surface portions 12 to 14 are pulled to the outside of the reflective sheet body 1 by this repulsive force, the side surface portions 12 to 14 are prevented from falling into the reflective sheet body 1.

Specifically, the operator bends the side surface portion 13 excessively with respect to the bottom surface portion 11, and the bending angle θ of the side surface portion 13 with respect to the bottom surface portion 11 causes the side surface portion 13 to fall toward the bottom surface portion 11. Even if the temperature is less than 90 °, the side surface portion 13 returns its collapse due to the action of the repulsive force of the corner portions 15 and 16.

In the example of FIG. 4, the fall prevention for the side surface portions 13 is described as a representative, and the fall prevention for the side surface portions 12 and 14 will be omitted. Further, in the example of FIG. 4, the side surface portion 14 is omitted in order to make it easier to understand the collapse of the side surface portion 13.

In the reflective sheet body 1, when the light guide plate 43 is assembled to the bottom surface portion 11, the side surface portions 12 to 14 do not enter below the back surface 43f of the light guide plate 43. Therefore, the reflective sheet body 1 can prevent the light guide plate 43 from riding on the side surface portions 12 to 14, and can efficiently assemble the light guide plate 43.

On the other hand, as shown in FIG. 5, in the reflective sheet body 1A not provided with the corner portions 15 and 16, if the side surface portion 13 is excessively bent, the light guide plate 43 is assembled to the bottom surface portion 11. At that time, there is a possibility that the side surface portion 13 may enter the lower side of the back surface 43f of the light guide plate 43.

Here, the corner portions 15 and 16 have a large amount of protrusion from the side surface portions 12 to 14. Therefore, the shape of the corner portions 15 and 16 of the reflective sheet 10 may be changed as appropriate. For example, as shown in FIGS. 6A to 6C, the corner portions 15 and 16 may have a chamfered shape. In the examples of FIGS. 6A to 6C, the corner portion 16 of the corner portions 15 and 16 is shown as a representative.

The corner portion 16 shown in FIG. 6A has a chamfered arc shape. The chamfered shape of the corner portion 16 shown in FIG. 6B is a straight line. The corner portion 16 shown in FIG. 6C has a chamfered arc shape. As a result, the corner portions 15 and 16 can reduce the amount of protrusion from the side surface portions 12 to 14 in the bent state when the reflective sheet body 1 is assembled.

Further, as shown in FIGS. 7A to 7D, the corner portions 15 and 16 may have perforations 10d. In the examples of FIGS. 7A to 7C, the corner portion 16 of the corner portions 15 and 16 is shown as a representative. The perforation 10d constitutes the second perforation and is provided on the center line which is the bending position of the corner portions 15 and 16. The perforations 10d of the corner portion 16 shown in FIG. 7A are installed at the same positions as the diagonal line 16a. As a result, the corner portions 15 and 16 are easily bent toward the outside of the side surface portions 12 to 14 as the side surface portions 12 to 14 are bent.

From the above, the non-incident side surfaces 43b to 43d and the back surface 43f of the light guide plate 43 having the incident side surface 43a on which the light emitted from the light source 42 is incident, the non-incident side surfaces 43b to 43d other than the incident side surface 43a, and the back surface 43f The rectangular reflective sheet 10 that covers the light guide plate 43 is connected to a bottom surface portion 11 that abuts on the back surface 43f and a plurality of sides of the bottom surface portion 11 that do not face the light source 42, and is bent with respect to the bottom surface portion 11. Occasionally, a plurality of side surface portions 12 to 14 facing the non-incident side surfaces 43b to 43d of the light guide plate 43 are connected to the side surface portions 12, 13 and 13 and 14 adjacent to each other, and the side surface portions 12 to 14 are connected. It is applied on the boundary line between the corner portions 15 and 16 which are bent outward from the side surface portions 12 to 14 as the bottom surface portion 11 is bent, and between the bottom surface portion 11 and the side surface portions 12 to 14. The perforations 10a to 10c are provided. As a result, the reflective sheet 10 can prevent the light guide plate 43 from riding on.

The corner portions 15 and 16 have a chamfered shape. As a result, the corner portions 15 and 16 can reduce the amount of protrusion from the side surface portions 12 to 14 in the bent state when the reflective sheet body 1 is assembled.

The reflective sheet 10 includes perforations 10d formed on the center lines of the corner portions 15 and 16. As a result, the reflective sheet 10 can easily bend the corner portions 15 and 16 toward the outside of the side surface portions 12 to 14 as the side surface portions 12 to 14 are bent.

Embodiment 2
The reflective sheet 20 according to the second embodiment will be described with reference to FIGS. 8 to 10. FIG. 8 is a diagram showing a reflective sheet 20 according to the second embodiment. FIG. 9 is a cross-sectional view showing the assembling operation of the reflective sheet 20 according to the second embodiment. FIG. 10 is a cross-sectional view showing another assembling operation of the reflective sheet 20 according to the second embodiment.

The reflective sheet 20 shown in FIG. 8 includes a bottom surface portion 11, side surface portions 12 to 14, and perforations 10c, 20a, and 20b. The perforation 10c constitutes the third perforation. At least one of the perforations 20a and 20b constitutes the fourth perforation.

The perforation 20a is parallel to the boundary line 20c between the bottom surface portion 11 and the side surface portion 12, and is provided on the bottom surface portion 11 side of the boundary line 20c. Further, the perforation 20a extends over the bottom surface portion 11 and the side surface portion 13. The perforation 20a is for making the side surface portion 12 more easily broken at the boundary line 20c with respect to the bottom surface portion 11.

The perforation 20b is parallel to the boundary line 20d between the bottom surface portion 11 and the side surface portion 13, and is provided on the bottom surface portion 11 side of the boundary line 20d. Further, the perforation 20b extends over the bottom surface portion 11 and the side surface portion 12. The perforation 20b is for making the side surface portion 14 easily broken at the boundary line 20d with respect to the bottom surface portion 11.

Further, the reflective sheet body 2 shown in FIG. 9 is a light reflecting structure formed by bending the reflective sheet 20 from the unfolded state, and has a box shape such that the front side and the light source 42 side are opened. ing. The reflective sheet body 1 is attached to the bottom surface of the housing 41 via a double-sided tape 45.

Therefore, as shown in FIG. 9, when the reflective sheet body 2 and the light guide plate 43 are assembled in the housing 41, the operator first attaches the double-sided tape 45 to a predetermined position on the bottom surface of the housing 41 in advance. paste.

The operator then bends the reflective sheet 20 along the perforations 10c, 20a, 20b. The perforation 10c is bent up to 90 °. The perforations 20a and 20b are bent at less than 90 °.

Then, the operator assembles the bent reflective sheet 20 into the housing 41. That is, the operator attaches the bottom surface portion 11 of the reflective sheet 20 to the double-sided tape 45. As a result, the reflective sheet 20 is temporarily fixed to the housing 41.

Subsequently, the operator attaches the light guide plate 43 to the reflective sheet 20 temporarily fixed to the housing 41. At this time, the light guide plate 43 is pressed against the reflective sheet 20, but since it is attached to the double-sided tape 45, the position does not shift.

When the light guide plate 43 is pushed into the housing 41, the side surface portions 12 and 13 of the reflective sheet 20 are pushed into the housing 41 and are bent at the boundary lines 20c and 20d, respectively. In this way, the reflective sheet 20 is formed on the reflective sheet body 1 and is assembled in the housing 41.

Then, the operator positions and fixes the light guide plate 43. As a result, the assembly of the reflective sheet body 2 and the light guide plate 43 is completed.

As described above, in the reflective sheet body 2, when the light guide plate 43 is assembled to the bottom surface portion 11, the side surface portions 12 to 14 do not enter below the back surface 43f of the light guide plate 43. Therefore, the reflective sheet body 2 can prevent the light guide plate 43 from riding on the side surface portions 12 to 14, and can efficiently assemble the light guide plate 43.

Further, as shown in FIGS. 8 and 10, the reflective sheet 20 may have the above-mentioned perforations 10b on the boundary line 20d of the reflective sheet 20. Since the perforations 10b of the reflective sheet 20 are naturally bent by assembling the light guide plate 43, no manual bending work is required. The perforation 10b constitutes a third perforation.

From the above, the non-incident side surfaces 43b to 43d and the back surface 43f of the light guide plate 43 having the incident side surface 43a on which the light emitted from the light source 42 is incident, the non-incident side surfaces 43b to 43d other than the incident side surface 43a, and the back surface 43f are formed. The rectangular reflective sheet 20 that covers the light guide plate 43 is connected to a bottom surface portion 11 that abuts on the back surface 43f and a plurality of sides of the bottom surface portion 11 that do not face the light source 42, and is bent with respect to the bottom surface portion 11. Occasionally, on the boundary line between the plurality of side surface portions 12 to 14 facing the non-incident side surfaces 43b to 43d of the light guide plate 43 and some of the side surface portions 14 of the bottom surface portion 11 and the plurality of side surface portions 12 to 14. Parallel to the boundary lines 20c and 20d between the perforations 10c made on the surface and at least one side surface portion 12 and 13 other than a part of the side surface portions 14 among the bottom surface portion 11 and the plurality of side surface portions 12 to 14. Moreover, the perforations 20a and 20b provided on the bottom surface portion 11 side of the boundary lines 20c and 20d are provided. As a result, the reflective sheet 20 can prevent the light guide plate 43 from riding on.

In the present invention, within the scope of the invention, any combination of embodiments, modification of any component in each embodiment, or omission of any component in each embodiment can be omitted. It is possible.

1,1A Reflective sheet body, 10 Reflective sheet body, 10a-10d Perforation, 11 Bottom part, 12-14 Side part, 15,16 Corner part, 15a, 16a diagonal, 2 Reflective sheet body, 20 Reflective sheet, 20a, 20b Perforations, 20c, 20d boundary line, 30 liquid crystal display, 31 liquid crystal panel, 32 backlight device, 41 housing, 41a notch, 42 light source, 43 light guide plate, 43a incident side, 43b to 43d non-incident side, 43e irradiation surface, 43f back surface, 44 prism sheet, 45 double-sided tape.

Claims (7)

A rectangular reflective sheet covering the non-incident side surface and the back surface of a light guide plate having an incident side surface on which light emitted from a light source is incident, a non-incident side surface other than the incident side surface, and a back surface.
A bottom surface portion of the light guide plate that contacts the back surface and
When connected to a plurality of sides of the bottom surface portion that do not face the light source and bent with respect to the bottom surface portion, the plurality of side surface portions that face the non-incident side surface of the light guide plate and
A corner portion that connects the side surface portions adjacent to each other and is bent toward the outside of the side surface portion as the side surface portion is bent with respect to the bottom surface portion.
A reflective sheet comprising a first perforation formed on a boundary line between the bottom surface portion and the side surface portion. The reflective sheet according to claim 1, wherein the corner portion has a chamfered shape. The reflective sheet according to claim 1 or 2, further comprising a second perforation formed on the center line of the corner portion. A rectangular reflective sheet covering the non-incident side surface and the back surface of a light guide plate having an incident side surface on which light emitted from a light source is incident, a non-incident side surface other than the incident side surface, and a back surface.
A bottom surface portion of the light guide plate that contacts the back surface and
When connected to a plurality of sides of the bottom surface portion that do not face the light source and bent with respect to the bottom surface portion, the plurality of side surface portions that face the non-incident side surface of the light guide plate and
A third perforation formed on a boundary line between the bottom surface portion and a part of the side surface portions among the plurality of side surface portions.
It is applied parallel to the boundary line between the bottom surface portion and at least one side surface portion other than the side surface portion of a part of the side surface portions, and on the bottom surface portion side of the boundary line. A reflective sheet characterized by having a fourth perforation. A reflective sheet body formed by bending the reflective sheet according to any one of claims 1 to 4 at a boundary line between the bottom surface portion and all the side surface portions. The reflective sheet body according to claim 5 and
A housing that holds the reflective sheet body and
A backlight device including a prism sheet facing the irradiation surface of the light guide plate housed in the reflection sheet and through which light emitted from the irradiation surface passes. The backlight device according to claim 6 and a liquid crystal panel are provided.
A liquid crystal display device characterized in that the back surface of the liquid crystal panel faces the irradiation surface, and the light that has passed through the prism sheet is irradiated to the back surface of the liquid crystal panel.

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