JP2007157500A - Manufacturing method of backlight device, and optical sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of backlight device capable of preventing optical sheets from excessively laying one upon the other, and to provide an optical sheet. <P>SOLUTION: A through hole 57 of a diffusion sheet 51A is out-fitted onto an protrusion 47 of a receiving member 42 after lifting up one sheet of optical sheets 51A at uppermost part out of the optical sheets piled up on a storing position, and exfoliating a laminate film 59 upper face side. At this time, in case that one optical sheet 51A is taken out (more than two sheets are not taken out by mistake), the optical sheet 51A can be put on the diffusion plate 50. In case that more than two optical sheets 51A are taken out (more than two sheets are taken out by mistake), tip part of the protrusion 47 is blocked by the laminate film 59, and the optical sheet 51A can not be put on the diffusion plate 50. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a backlight device and an optical sheet.

  In a backlight device for a liquid crystal display device, a plurality of optical sheets are laminated so that light emitted from a light source is evenly irradiated on a display.

  By the way, in the assembled state, the backlight device must include these optical sheets without shortage. However, the optical sheets generally have the same or similar thin plate shape and are stacked. When viewed from above in a combined state, it is difficult to distinguish them from each other. Therefore, even if there is a shortage in the number of laminated optical sheets, such a shortage cannot be easily recognized.

Therefore, as shown in Patent Document 1, the corner of each optical sheet is cut off with a straight line, and the cut-off amount varies depending on each sheet (triangular shapes cut off from each sheet are similar to each other). It was conceived that a small number of sheets were placed down, and sheets with a large amount of cut off were gradually stacked up. By doing so, the cut-off site is visually observed from above in the manufacturing process so that the shortage (out of stock) of the optical sheet in the assembly can be recognized.
JP 2004-125964 A (FIG. 2)

  By the way, when laminating optical sheets, not only the above-described mistake of insufficient number of laminated sheets but also the mistake of laminating extra optical sheets may occur. In such a case, in the above configuration, when the same optical sheet (sheet having the same cut-off amount and the same shape) is excessively stacked, the optical sheet that is excessively stacked is visually recognized in a manufacturing process or the like. It was difficult.

  The present invention has been completed based on the above situation, and an object of the present invention is to provide a method for manufacturing a backlight device and an optical sheet that can prevent the optical sheets from overlapping excessively. .

As means for achieving the above object, the present invention (first invention) is a method for manufacturing a backlight device in which an optical sheet having translucency is superimposed on the front side of a panel disposed in front of a light source. In the method of taking out the optical sheets one by one from a predetermined supply unit and stacking the optical sheets on the panel, a visible identification member is attached to a surface opposite to the panel on the optical sheet in the supply unit. The identification member is peeled off from the surface opposite to the panel after the optical sheet is taken out from the supply unit.
In this way, when a plurality of optical sheets are stacked, even if the identification member attached to the surface opposite to the panel of one optical sheet is peeled off, the optical sheet is attached to another optical sheet. The attached identification member is left.

In the present invention (second invention), a light source is accommodated in a main body casing having an opening on one surface, and an optical material having translucency on the front side of a panel disposed in the opening in front of the light source. In the method of manufacturing a backlight device in which sheets are stacked, the optical sheets are taken out one by one from a predetermined supply unit and stacked on the panel, and a through hole is provided on an edge side of the optical sheet. On the other hand, the main body casing is provided with an insertion protrusion that can be inserted into the through hole, and an optical identification member that is visible so as to cover the through hole is attached to the optical sheet in the supply unit. Further, the present invention is characterized in that the discriminating member is peeled off after the optical sheet is taken out from the supply unit.
In this way, when a plurality of optical sheets are overlapped, when the optical sheets are stacked on the front surface side of the panel, the insertion protrusion has a through hole formed by the identification member existing between the plurality of optical sheets. I can't pass.

The present invention (third invention) is an optical sheet having translucency that is taken out from a predetermined supply unit one by one on the front side of a panel disposed in front of the light source, and is stacked on the supply unit. A certain optical sheet has a visible identification member affixed to a surface opposite to the panel, and after the optical sheet is taken out from the supply unit, the identification member is opposite to the panel. It is characterized in that it is configured to be peeled off from the surface.
In this manner, when a plurality of optical sheets are overlapped, when the identification member attached to the exposed surface side is peeled off, the identification member attached to another optical sheet is left.

  According to the present invention (fourth invention), a light-transmitting optical element is stacked one by one from among a plurality of prepared optical sheets on the front side of a panel disposed in front of a light source accommodated in a main body casing. The sheet has a structure in which a through hole into which an insertion protrusion provided to protrude from the main body casing can be inserted is provided on the edge side, and the identification member that covers the through hole is attached. Has characteristics.

  In this way, when a plurality of optical sheets are overlapped, when the optical sheets are stacked on the front surface side of the panel, the insertion protrusion has the through hole formed by the identification member existing between the plurality of optical sheets. I can't pass.

As an embodiment of the present invention (the third invention and the fourth invention), the following constitution is preferable.
-The said identification member is colored. Thereby, it can be easily recognized that a plurality of optical sheets are stacked.

-The said identification member is affixed so that at least one part may protrude from the said optical sheet. Thereby, it can be easily recognized that a plurality of optical sheets are overlapped by the protruding portion.

The different types of optical sheets are sequentially stacked on the front side of the panel, and the identification member is attached to different positions for the different types of optical sheets. Thereby, the shortage of the optical sheet can be recognized.
The identification member has a visible mark. Thereby, it can be easily recognized that a plurality of optical sheets are stacked.

The optical sheet is arranged between a backlight and a liquid crystal panel, and an edge portion of the optical sheet is extended to outside the display area of the liquid crystal panel, and the identification member is the optical sheet Of these, it is affixed to a portion outside the display area. Thus, even when the optical sheet is bent when the identification member is removed, the display quality is not affected because it is a portion outside the display area.

  According to the present invention, since the overlap of the optical sheets can be recognized, it is possible to prevent the optical sheets from overlapping one another.

<Embodiment 1>
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an exploded perspective view of a display device 10 that performs display using the backlight device 30 of the present invention. FIG. 2 is a plan view of the display device 10. FIG. 3 is a cross-sectional view of the display device 10 taken along the line AA. Hereinafter, the light irradiation direction (upper side in the drawing) in the backlight device 30 will be described as the front side, and the opposite side will be described as the rear side.
1. Overall Configuration As shown in FIG. 1, the display device 10 is mainly configured by a liquid crystal panel 20 having a planar shape capable of displaying an image and a backlight device 30.

  The liquid crystal panel 20 includes a pair of glass substrates, a liquid crystal filled between the glass substrates, and a pair of polarizing plates attached to the outer surfaces of the glass substrates, and these are disposed above the backlight device 30. It has come to be. The liquid crystal panel 20 is sandwiched between the outer frame 21 and the inner frame 22 that form a frame shape, so that they are held in an overlapped state.

  The backlight device 30 is a so-called direct-type backlight device 30 in which a plurality of cold cathode tubes 31 are arranged side by side at a position directly below the liquid crystal panel 20, and a base that accommodates the cold cathode tubes 31 therein. The tray 40, a diffusion plate 50 (corresponding to the “panel” of the present invention) disposed so as to close the opening 48 on the upper surface of the base tray 40, and three optical sheets 51A to 51C stacked on the diffusion plate 50 And is configured.

  As shown in FIG. 3, the base tray 40 includes a metal box-shaped base panel 41 having an upper surface opened, and a synthetic resin receiving member 42 disposed inside the base panel 41 ( (See FIG. 3).

The receiving member 42 has a frame shape that follows the outer shape of the diffusing plate 50, and is fitted to the inner periphery of the base panel 41 without a gap.
The upper surface of the receiving member 42 is a flat seat surface 43, and an upright piece 44 is provided on the outer edge portion of the seat surface 43 so as to rise upward over the entire circumference.

  The diffusion plate 50 is disposed in the opening 48 on the inner side of the upright piece 44 (the space between the upright pieces 44 facing each other at both ends of the base tray 40), and the peripheral portion 50A of the diffusion plate 50 is the receiving member. 42 is supported by the seating surface 43.

  As shown in FIG. 2, the outer periphery (peripheral portion) of the base panel 41 is formed with a plurality of projecting portions 45 projecting outward, and standing pieces provided along the outer periphery of the base panel 41. Positioning recesses 46 are formed on the inner surface of 44 at positions corresponding to the overhanging portions 45 (four on the left side and right side shown in FIG. 2, and one on each of the upper side and lower side). An overhang 45 and a positioning recess 46 are provided.

  As shown in FIG. 1, the diffusion plate 50 and the three optical sheets 51 </ b> A to 51 </ b> C are formed in a rectangular shape having substantially the same size, and of these peripheral portions, the opposing positions of the positioning recesses 46 of the base tray 40 are provided. A positioning convex portion 56 (56A, 56B) that slightly protrudes outward is formed. By aligning the positioning convex portion 56 with the positioning concave portion 46 corresponding to the positioning convex portion 56, the diffusion plate 50 and the three optical sheets 51 </ b> A to 51 </ b> C are in the surface direction (up and down, left and right direction in FIG. 2). Is positioned.

  The diffusion plate 50 is for making the luminance distribution uniform by diffusing light from the linear light source. As shown in FIG. 3, the diffusion plate 50 is thicker than the optical sheets 51 </ b> A to 51 </ b> C and is less likely to be bent, and can support the optical sheets 51 </ b> A to 51 </ b> C placed on the front side in a substantially straight shape. It is like that.

  The three optical sheets 51 are, in order from the bottom, a diffusion sheet 51A, a lens sheet 51B, and a brightness enhancement sheet 51C, and these are stacked on the diffusion plate 50.

The diffusion sheet 51A is for making the luminance distribution uniform by diffusing light.
The lens sheet 51B is for increasing the luminance when the display device 10 is viewed from the front by condensing the light emitted from the diffusion sheet 51A.
The brightness increasing sheet 51C is for increasing the overall brightness including the brightness when the display device 10 is viewed obliquely.

  In this way, the diffuser plate 50 and the optical sheets 51A to 51C can convert substantially linear light emitted from each cold cathode tube 31 into planar light so that the liquid crystal panel 20 can be irradiated with no spots. It has become. Here, the size of the diffusion plate 50 and the optical sheets 51A to 51C is the display area of the liquid crystal panel 20 corresponding to the size of the inner part of the outer frame 21 in the display device 10 (the outer area indicated by the two-dot chain line in FIG. 2). It has a rectangular surface slightly larger than the area on the inner side of the frame 21. That is, the area surrounded by the two-dot chain line 21A. As a result, the positioning recess 46 and the positioning projection 56 are arranged at positions that avoid the display area of the liquid crystal panel 20.

  The diffusion plate 50 and the three optical sheets 51 </ b> A to 51 </ b> C are sandwiched and held between the inner frame 22 and the receiving member 42 of the base tray 40. The base tray 40, the inner frame 22, and the outer frame 21 constitute a main body casing of the present invention.

2. A structure for preventing a plurality of optical sheets 51A to 51C from being stacked at the time of assembly. Of the seating surface 43 of the receiving member 42, the portion in the positioning recess 46 of the receiving member 42 on the right side in FIG. The insertion protrusion 47 protrudes upward. The insertion protrusion 47 has a slightly thin cylindrical shape, and its tip is a flat surface.

  Of the positioning convex portions 56 on one side of the optical sheets 51A to 51C (the diagonally lower right side in FIG. 1), a pair of positioning convex portions 56A near both ends protrude slightly from the other positioning convex portions 56B and are positioned. A through hole 57 penetrating in the vertical direction is provided at the center of the convex portion 56A. The through hole 57 is slightly larger than the insertion protrusion 47 of the receiving member 42. When the optical sheets 51 </ b> A to 51 </ b> C are stacked on the diffusion plate 50, the rod-shaped insertion protrusion 47 is inserted into the through hole 57. It is designed to be inserted inside.

  By the way, as shown in FIG. 4, these optical sheets 51A to 51C are stacked for each of the optical sheets 51A to 51C in a stacked state (in the “supply section” of the present invention). The optical sheet 51A (up to 51C) of the uppermost layer is taken out of the optical sheets 51A (up to 51C) stored in the storage position corresponding to the operator at the time of assembly, and the base tray The 40 receiving members 42 are stacked in the order (51A → 51B → 51C).

  Here, on the optical sheets 51A to 51C before being assembled (in a state where they are stacked at the accommodation position), the laminate film 59 (of the present invention) is formed so as to cover the entire through hole 57 on the upper surface portion of the positioning convex portion 56A. "Corresponding to" identification member ") is pasted to such an extent that it can be peeled off by an adhesive or the like (see FIG. 6).

  The laminate film 59 is a translucent sheet made of a thin plastic and is slightly colored (red, etc.). Thereby, the user can easily recognize that the laminate film 59 is affixed.

3. Next, a method for manufacturing the backlight device 30 will be described. In the present embodiment, the assembly of the backlight device 30 is performed by an operator.

  An operator attaches the receiving member 42 to the inside of the base tray 40 that accommodates the cold cathode tube 31 therein, and arranges the diffusion plate 50 on the seating surface 43 of the receiving member 42 (state of FIG. 5).

<Method of taking out optical sheets one by one and stacking them on a diffusion plate>
Next, as shown in FIG. 4, the operator lifts the uppermost one of the diffusion sheets 51 </ b> A stacked at the accommodation position. Then, as shown in FIG. 6, after the laminate film 59 attached to the upper surface of the positioning convex portion 56 </ b> A is peeled off (upper stage in FIG. 6), the insertion protrusion 47 of the member 42 receives the through hole 57 of the positioning convex portion 56 </ b> A. (In the middle of FIG. 6).
At this time, if there is one diffusion sheet 51A (if two or more sheets are not taken out by mistake), the insertion protrusion 47 is inserted into the through hole 57, and the diffusion sheet 51A is overlaid on the diffusion plate 50 ( FIG. 6 bottom).

  On the other hand, as shown in FIG. 7, when two or more diffusion sheets 51A stacked in the accommodation position are taken out (when two or more sheets are mistakenly taken out) (upper stage in FIG. 7), the upper diffusion sheet 51A is taken. After the laminate film 59 attached to the upper surface of the positioning convex portion 56A is peeled off (in the middle of FIG. 7), the through hole 57 of the positioning convex portion 56A is received into the insertion protrusion 47 of the member 42.

  At this time, since the laminated film 59 of the lower diffusion sheet 51A is left without being peeled, the corresponding insertion protrusion of the member 42 receiving the through hole 57 of the positioning protrusion 56A. Even if it tries to insert into 47, the front-end | tip 47A of the insertion protrusion 47 is caught by the laminate film 59, and the diffusion sheet 51A cannot be piled up on the diffusion plate 50 (lower stage of FIG. 7).

  As a result, it can be seen that two or more diffusion sheets 51A have been taken out in an overlapped state. Therefore, the extra diffusion sheet 51A is returned to the accommodation position, the number of diffusion sheets 51A is set to one, and the diffusion plate 50 The diffusion sheet 51A is stacked on top.

Thereafter, the same operation is performed in order for the lens sheet 51B and the brightness enhancement sheet 51C, and the number of the lens sheet 51B and the brightness enhancement sheet 51C is set to one, and then is sequentially stacked on the diffusion plate 50.
Thereby, the backlight apparatus 30 is assembled | attached, without overlapping two or more sheets about each of optical sheet 51A-51C.

4). Advantages of the present embodiment (1) According to the present embodiment, the optical sheets 51A to 51C stacked in the accommodation position (supply unit) are visible on the surface opposite to the diffusion plate 50 (panel). A laminate film 59 (identification member) is affixed, and after the optical sheet 51 is taken out from the storage position, the laminate film 59 is peeled off from the surface opposite to the diffusion plate 50. Therefore, when a plurality of optical sheets 51 are overlapped, even if the laminated film 59 attached to the surface opposite to the diffusion plate 50 of one optical sheet 51A (˜51C) is peeled off, The laminate film 59 attached to the optical sheet 51A (˜51C) is left. Since the remaining laminate film 59 can recognize the overlap of the optical sheet 51, it is possible to prevent the optical sheet 51 from being excessively overlapped.

(2) The positioning projection 56A (edge side) of the optical sheet 51 is provided with a through hole 57, while the receiving member 42 (main body casing) is provided with an insertion protrusion 47 that can be inserted into the through hole 57. In addition, a visible laminate film 59 is attached to the optical sheet 51 in the storage position so as to cover the through-hole 57. After the optical sheet 51 laminated in the storage position is taken out, the laminate film 59 is removed. Is peeled off. Therefore, when a plurality of optical sheets 51 are overlapped, when the optical sheets 51 are stacked on the front side of the diffusion plate 50, the insertion protrusion 47 is formed by the laminate film 59 existing between the plurality of optical sheets 51. Since it does not pass through the through-hole 57, it can be recognized that a plurality of optical sheets 51 overlap each other.

(3) The laminate film 59 is attached to a portion of the optical sheet 51 outside the display area. Accordingly, even when the optical sheet 51 is bent when the laminate film 59 is removed, the display quality is not affected because it is a portion outside the display area.

<Embodiment 2>
In the first embodiment, the laminate film 59 (identification member) is attached in the region of the optical sheet 51 (positioning convex portion 56A). However, in the second embodiment (corresponding to the invention of claim 6), FIG. As shown in FIG. 4, the identification film 60 (identification member) is pasted so as to protrude from the region of the optical sheet 51 (51A). Further, unlike the first embodiment, the through hole 57 (positioning convex portion 56A) of the optical sheet 51 and the insertion protrusion 47 of the main body casing are not provided. In addition, about the structure same as embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  As shown in FIG. 8, the identification film 60 is made of a synthetic resin, has a rectangular shape, and one end side in the long side direction can be peeled off at the edge of the upper surface of the optical sheet 51 (outside the display area of the liquid crystal panel 20). The other end side sticks out of the optical sheet 51.

Next, a method for taking out the optical sheets 51 one by one and stacking them on the diffusion plate 50 will be described.
The uppermost one of the optical sheets 51A stacked at the accommodation position (supply unit) is lifted, and the identification film 60 is peeled off from the upper surface side of the optical sheets 51A.

  In addition, it is confirmed (visually confirmed) whether or not the identification film 60 is attached. If no other identification film 60 is attached, it can be seen that the number of optical sheets 51 </ b> A is one, and thus the optical sheet 51 </ b> A is stacked on the diffusion plate 50. On the other hand, as shown in FIG. 9, if another identification film 60 is attached, it can be understood that two or more optical sheets 51A (3 sheets in FIG. 9) are mistakenly taken out. The optical sheet 51A is returned to the accommodation position, and the optical sheet 51A is stacked on the diffusion plate 50 after the number of the optical sheets 51A is set to one.

  Hereinafter, similarly for the optical sheets 51B and 51C, the uppermost one of the optical sheets 51B stacked in the storage position is lifted, the identification film 60 is peeled off from the upper surface side, and the identification film 60 is not attached. Confirm (visually check). Then, according to the confirmation result, the number of the optical sheets 51B (51C) is set to one and then stacked on the diffusion plate 50 in order.

  Thus, since at least a part of the identification film 60 (identification member) is attached so as to protrude from the optical sheet 51, it is easily recognized that a plurality of optical sheets 51 are overlapped by the protruding part. can do.

<Embodiment 3>
In the second embodiment, different types of optical sheets 51 are configured such that the identification film 60 is attached at the same position. However, in the third embodiment (corresponding to the invention of claim 7), as shown in FIG. The identification film 70 (70A, 70B, 70C) is affixed on a different position for each type of optical sheet 51.

  Specifically, as shown in FIG. 11, the optical sheet 51A is attached to the upper end side of FIG. 10, the optical sheet 51B is attached to the center portion, and the optical sheet 51C is attached to the lower end side. It is pasted.

  Thus, since the identification film 70 (identification member) is affixed to different positions for different types of optical sheets 51, the optical sheet 51 is easily deficient (of type) by visually recognizing the optical sheet 51. Can be recognized.

<Embodiment 4>
In the said embodiment, the color of the identification films 60 and 70 (or laminate film 59) is made uniform (plain) as a whole. On the other hand, in Embodiment 4 (corresponding to the invention of claim 8), a visible mark M is attached to a part of the laminate film or the identification film.

  Specifically, as shown in FIG. 12, a translucent identification film 80 is affixed to the corner of the optical sheet 51, and the identification film 80 has a colored mark M (in FIG. 12, a circular X mark). ) Is attached.

  Thus, since the identification film 80 (identification member) has a visually recognizable mark, it can be easily recognized that a plurality of optical sheets 51 are stacked.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) In the above embodiment, a so-called direct-type backlight device in which the cold cathode tube 31 as a light source is disposed directly below the liquid crystal panel 20 has been illustrated, but a so-called sidelight in which the light source is disposed on the side. The present invention may be applied to a type of backlight device.

(2) In Embodiment 1, the positioning recess 46 and the positioning projection 56 are provided on the long side of the backlight device. However, the positioning recess 46 and the positioning projection 56 may be provided on the short side of the backlight device. Good. Moreover, although the two positioning convex parts 56 (positioning concave part 46) were provided, one or three or more may be sufficient.

(3) In the first embodiment, the optical sheet 51 is attached to the upper surface of the positioning convex portion 56 </ b> A. However, the optical sheet 51 may be attached to another part of the optical sheet 51. Further, for example, it may be used as a laminate sheet that has a function of protecting the optical sheet 51 by being attached to the entire surface of the optical sheet 51.

(4) Although the assembly of the backlight device 30 is performed by an operator, it may be performed automatically. For example, an operator performs peeling of the laminate film 59 and visual recognition of the number of optical sheets 51, and other work steps (such as arrangement of the diffusion plate 50 and stacking of the optical sheets 51) are automated by a production line or the like. May be performed.

1 is an exploded perspective view of a display device according to Embodiment 1. FIG. Flat section of display device AA sectional view of a display device The figure which shows a mode that an optical sheet is supplied from several supply parts. Sectional drawing which shows the assembly | attachment state before an optical sheet is piled up on a diffusion plate The figure explaining a mode that an optical sheet is piled up on a diffusion plate The figure explaining a mode that it is going to pile up on a diffusion plate in the state where a plurality of optical sheets overlapped Top view of an optical sheet according to Embodiment 2 Cross section of optical sheet The top view of the state where the optical sheet concerning Embodiment 3 was piled up Top view of each optical sheet Top view of optical sheet according to Embodiment 4

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Display apparatus 20 ... Liquid crystal panel 21 ... Outer frame 22 ... Inner frame 30 ... Backlight apparatus 40 ... Base tray 41 ... Base panel 42 ... Receiving member 46 ... Positioning recessed part 47 ... Insertion protrusion 50 ... Diffusing plate 51A-51C ... Optical sheet 56 (56A, 56B) ... positioning projection 57 ... through hole 59 ... laminate film (identification member)
60, 70, 80 ... identification film (identification member)

Claims (9)

A method for manufacturing a backlight device in which an optical sheet having translucency is superimposed on the front side of a panel disposed in front of a light source,
In the method in which the optical sheets are taken out one by one from a predetermined supply unit and stacked on the panel, a visible identification member is attached to a surface opposite to the panel on the optical sheet in the supply unit. And after taking out the optical sheet from the supply section, the identification member is peeled off from the surface opposite to the panel. A method of manufacturing a backlight device in which a light source is accommodated in a main body casing having an opening on one surface, and a light-transmitting optical sheet is stacked on a front surface side of a panel disposed in the opening in front of the light source Because
In the method in which the optical sheets are taken out one by one from a predetermined supply unit and stacked on the panel, a through hole is provided on the edge side of the optical sheet, while the main body casing can be inserted into the through hole. Insertion protrusion is provided,
On the optical sheet in the supply unit, a visible identification member is attached so as to cover the through hole,
A method for manufacturing a backlight device, comprising: peeling off the identification member after taking out the optical sheet from the supply unit. An optical sheet having translucency that is taken out and stacked one by one from a predetermined supply unit on the front side of the panel disposed in front of the light source,
A visible identification member is affixed to the surface opposite to the panel on the optical sheet in the supply unit, and after the optical sheet is taken out from the supply unit, the identification member is connected to the panel. Is an optical sheet that is peeled off from the opposite surface. An optical sheet having translucency that is stacked one by one from among a plurality of prepared optical sheets on the front side of a panel disposed in front of a light source accommodated in a main body casing,
An optical sheet, wherein a through hole into which an insertion protrusion provided to protrude from the main body casing can be inserted is provided on an edge side, and the identification member covering the through hole is attached. The optical sheet according to claim 3 or 4, wherein the identification member is colored. The optical sheet according to claim 3, wherein the identification member is pasted so that at least a part thereof protrudes from the optical sheet. The optical sheets of different types are sequentially stacked on the front side of the panel,
The optical sheet according to any one of claims 3 to 6, wherein the identification member is affixed to different positions for the different types of optical sheets. The optical sheet according to claim 3, wherein the identification member has a visible mark. The optical sheet is disposed between the backlight and the liquid crystal panel, and the edge of the optical sheet extends outside the display area of the liquid crystal panel.
The optical sheet according to claim 3, wherein the identification member is affixed to a portion outside the display region of the optical sheet.

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