JP2011048290A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve light utilization efficiency in a liquid crystal display device using a light guide plate manufactured by heat transfer. <P>SOLUTION: The liquid crystal display device includes a liquid crystal panel, and a backlight disposed on the back side of the liquid crystal panel and including a light guide plate 8 and a light emitting element for emitting light on at least an incident plane 13 as one side of the light guide plate 8. The incident plane 13 includes at least a first plane 132 on which light is made incident from the light emitting element, and a second plane 133 whose surface is rougher than that of the first plane 132. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device.

  In recent years, liquid crystal display devices are frequently used as display devices. In particular, the liquid crystal display device is used in a display portion of a portable device because it is thin, lightweight, and saves power.

  However, since the liquid crystal display device is not a self-luminous type, it requires illumination means. 2. Description of the Related Art A planar lighting device called a backlight is widely used as a lighting device generally used in a liquid crystal display device. Conventionally, a cold cathode discharge tube is used as a light emitter (also referred to as a light source) of a backlight, but in recent years, a light emitting diode has also been used as a light emitter.

  As a thin backlight, there is a sidelight type backlight having a light emitter on a side surface. The sidelight type backlight is provided with a plate-shaped light guide plate. The material of the light guide plate is translucent resin or the like, and light that has entered the incident surface, which is the side surface of the light guide plate, from the light emitter propagates through the light guide plate. The light guide plate is provided with reflection / scattering members such as grooves, protrusions, printing on the surface, and scatterers dispersed in the light guide plate, and light transmitted through the light guide plate by the reflection / scattering member is liquid crystal The light is scattered and emitted toward the display device side.

  The proposal which forms a light-guide plate with sheet-like resin has description in the following patent document 1, for example. However, in the light guide plate described in the same document, light is emitted by including a scatterer having a specific refractive index in the sheet, and a groove is not formed on the sheet surface. It is difficult to control the distribution.

  Moreover, the following patent document 2 has description of the groove | channel and protrusion provided in the light-guide plate. However, Patent Document 2 does not describe a method for manufacturing a light guide plate.

  Usually, a method for producing a light guide plate having grooves on the surface uses a melt molding method such as injection molding. However, in the melt molding method, when the thickness of the light guide plate is reduced, the releasability is deteriorated, so that it is difficult to make the light guide plate thinner to some extent. Therefore, the applicant is considering to manufacture a light guide plate by thermal transfer using a thin sheet material. This involves heating the thin sheet material and pressing the mold against its surface to transfer the grooves formed in the mold surface to the surface of the sheet material, and then cutting out the sheet material to guide it to the desired size. This is a method for obtaining a light plate. According to this method, a thin light guide plate can be obtained, and a large number of light guide plates can be easily obtained from one large sheet material. Therefore, an advantage can be expected in terms of manufacturing cost.

  However, when the applicant uses the light guide plate obtained by the above method for a sidelight-type backlight, the incident surface, which is the side surface of the light guide plate, becomes a cut surface when the sheet material is cut out, and the surface is rough. It has been found that the efficiency of light use decreases because part of the incident light is irregularly reflected.

JP 2002-22966 A JP 07-43710 A

  The present invention has been made in view of such circumstances, and a problem to be solved is to improve light use efficiency in a liquid crystal display device using a light guide plate manufactured by thermal transfer.

  Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.

  (1) A liquid crystal panel, a light guide plate disposed on the back side of the liquid crystal panel, and a backlight having a light emitter that enters light on an incident surface that is at least one side surface of the light guide plate, The liquid crystal display device, wherein the incident surface includes at least a first surface on which light from the light emitter is incident and a second surface having a surface roughness rougher than that of the first surface.

  (2) In (1), the first surface and the second surface extend in a longitudinal direction of the incident surface, and the first surface is an irradiation region irradiated with light from the light emitter. The liquid crystal display device is arranged to include, and the second surface is arranged in a non-irradiation region where light from the issuer is not irradiated.

  (3) In (1), the first surface and the second surface extend in the longitudinal direction of the incident surface, and the second surface is the front surface side or the back surface of the light guide plate in the incident surface. A liquid crystal display device provided on the side edge.

  (4) The liquid crystal display device according to (1), wherein the first surface is inclined with respect to a normal direction of a surface of the light guide plate.

  According to the invention disclosed in the present application, light use efficiency can be increased in a liquid crystal display device using a light guide plate manufactured by thermal transfer.

It is a top view which shows the liquid crystal display device which concerns on one Embodiment of this invention. It is the schematic of the light emitting diode which is a light-emitting body. It is the schematic plan view and schematic side view of a light-guide plate and a light-emitting body. It is a figure explaining the light reflected by a groove | channel. It is a perspective view of the entrance plane vicinity of a light-guide plate. It is a figure which shows the positional relationship with respect to the light emitting diode of a 1st surface and a 2nd surface. It is the figure which showed typically the process of manufacturing a light-guide plate. It is the figure which expanded the B section of Drawing 7 (d). It is a figure which shows the light-guide plate which formed the 2nd surface in the edge of the surface side (side in which the light emission surface is formed) of a light-guide plate. It is a figure which shows the type | mold for manufacturing the light-guide plate shown in FIG.

  FIG. 1 is a plan view showing a liquid crystal display device 1 according to an embodiment of the present invention. The liquid crystal display device 1 includes a liquid crystal panel 2, a backlight 3, and a control circuit 4. From the control circuit 4, a signal necessary for display of the liquid crystal display device 1 and a power supply voltage are supplied. The control circuit 4 is mounted on the flexible substrate 5, and a signal is transmitted to the liquid crystal panel 2 via the wiring 6 and the terminal 7.

  The backlight 3 includes a light guide plate 8, a light emitting diode 9, and a storage case 10. The backlight 3 is provided for the purpose of irradiating the liquid crystal panel 2 with light. The liquid crystal panel 2 performs display by controlling the transmission amount or reflection amount of light emitted from the backlight 3. The backlight 3 is provided so as to be overlapped on the back side or the front side of the liquid crystal panel 2 with respect to the observer, but is shown side by side with the liquid crystal panel 2 in FIG. 1 for easy understanding.

  The light guide plate 8 has a substantially rectangular shape, and a light emitting diode 9 is provided on a side surface. Reference numeral 11 denotes a flexible substrate that electrically connects the plurality of light emitting diodes 9. The flexible substrate 11 and the control circuit 4 are electrically connected by a wiring 12.

  The side surface of the light guide plate 8 on which the light emitting diode 9 is disposed is referred to as an incident surface 13, and light incident on the light guide plate 8 from the incident surface 13 is emitted from the light emitting surface 14. An inclined portion 15 is formed between the incident surface 13 and the light emitting surface 14, and guides light from the incident surface 13 to the light emitting surface 14. The incident surface 13 and the inclined portion 15 form a light incident portion 16 and efficiently transmit light from the light emitting diode 9 to the light emitting surface 14. The details of the light incident section 16 will be described later.

  Next, the liquid crystal panel 2 will be described. The liquid crystal panel 2 has two substrates, a TFT substrate 17 and a color filter substrate 18, and a liquid crystal composition is sandwiched between the two stacked substrates. The TFT substrate 17 is provided with a pixel portion 19, and the pixel portion 19 is provided with a pixel electrode 20. Although the liquid crystal panel 2 includes a large number of pixel portions 19 in a matrix, only one pixel portion 19 is shown in FIG. The pixel portions 19 arranged in a matrix form a display region 21, and each pixel portion 19 plays a role of a pixel of a display image and displays an image in the display region 21.

  In FIG. 1, a gate signal line (also called a scanning line) 22 extending in the x direction and arranged in parallel in the y direction, and a drain signal line (video) extending in the y direction and arranged in parallel in the x direction. 23, which is also called a signal line), and the gate signal line 22 and the drain signal line 23 intersect each other. The pixel portion 19 is formed in a region surrounded by the gate signal line 22 and the drain signal line 23.

  A switching element 24 is provided in the pixel unit 19. A control signal is supplied from the gate signal line 22 to control on / off of the switching element 24. When the switching element 24 is turned on, the video signal transmitted through the drain signal line 23 is supplied to the pixel electrode 20.

  The drain signal line 23 is connected to the drive circuit 25, and a video signal is output from the drive circuit 25. The gate signal line 22 is connected to the drive circuit 26, and a control signal is output from the drive circuit 26. The gate signal line 22, the drain signal line 23, the drive circuit 25, and the drive circuit 26 are formed on the same TFT substrate 17. It is also possible to form the drive circuit 25, the drive circuit 26, and the control circuit 4 on one semiconductor chip.

  Next, FIG. 2 shows a schematic view of a light emitting diode 9 which is a light emitter. 2A is a schematic sectional view, and FIG. 2B is a front view of the light emission side.

  The light emitting diode 9 has a structure in which a light emitting diode chip 901 as a light emitting portion is mounted on a chip substrate 902. The light emitting diode chip 901 has a pn junction, and emits light at a specific wavelength when a voltage is applied to the pn junction. A p-type semiconductor layer forming a pn junction is provided with a p-electrode (anode) 903, and an n-type semiconductor layer is provided with an n-electrode (cathode) 904.

  A wire 905 is connected to the p electrode 903 and the n electrode 904. A wire 905 electrically connects a chip terminal 906 provided to connect the light emitting diode 9 to the outside, and a p-electrode 903 and an n-electrode 904.

  A fluorescent light emitting unit 907 may be provided on the light emitting surface side of the light emitting diode chip 901. The fluorescent light emitting unit 907 has a function of converting the wavelength of light emitted from the light emitting diode chip 901. Reference numeral 908 is a reflection unit that reflects light forward. An emission surface 909 from which light is emitted is formed on the front side of the light emitting diode 9.

  Next, FIG. 3A shows a schematic plan view of the light guide plate 8 and the light emitter, and FIG. 3B shows a schematic side view thereof. The light guide plate 8 is substantially rectangular as shown in FIG. 3A, and has a light emitting surface 14 on the upper surface and a scattering surface 27 on the lower surface as shown in FIG. 3B. The light guide plate 8 is made of a material that transmits light, such as acrylic resin or polycarbonate, and in the present embodiment, has a sheet shape with a thickness of 1.0 mm to 0.1 mm.

  As shown in FIG. 3B, the light guide plate 8 has a substantially rectangular cross section, but an inclined portion 15 is formed from the incident surface 13 toward the light emitting surface 14. The inclined portion 15 guides light from the light emitting diode 9 toward the light emitting surface 14 when the light emitting diode 9 is thicker than the light emitting surface 14 of the light guide plate 8. That is, it is preferable that the inclined portion 15 is provided when the thickness of the light emitting surface 14 of the light guide plate 8 is smaller than the thickness of the light emitting diode 9, since the light use efficiency increases. On the other hand, when the thickness of the light emitting surface 14 of the light guide plate 8 is greater than or substantially equal to the thickness of the light emitting diode 9, the inclined portion 15 may not be provided.

  In FIG. 3, the positional relationship between the light guide plate 8, the light emitting diode 9, and the flexible substrate 11 is shown. An incident surface 13 is provided on at least one side of the light guide plate 8, and a plurality of light emitting diodes 9 are provided in the vicinity of the incident surface 13. The light emitting diodes 9 are arranged along the incident surface 13 below the flexible substrate 11.

  An adhesive sheet (not shown) is provided on the light guide plate 8 side of the flexible substrate 11, and the position of the light emitting diode 9 is relative to the incident surface 13 by bonding and fixing the flexible substrate 11 to the light guide plate 8. Combined.

  Next, the light 28 emitted from the light emitting diode 9 will be described with reference to FIG. The light 28 emitted from the light emitting diode 9 enters the light guide plate 8 from the incident surface 13. Since the refractive index of the light guide plate 8 is larger than that of air, the light 28 that has reached the incident surface 13 at an angle larger than a specific angle with respect to the normal direction of the incident surface 13 is reflected, and the light 28 that has reached a small angle is guided. The light enters the inside of the light plate 8.

  The light emitting surface 14 and the scattering surface 27 of the light guide plate 8 are substantially orthogonal to the incident surface 13, and the light 28 entering the light guide plate 8 is totally reflected by the light emitting surface 14 and the scattering surface 27 of the light guide plate 8. Repeatedly proceeds through the light guide plate 8. The scattering surface 27 is provided with a V-shaped groove 29 as a reflection / scattering member. A part of the light 28 traveling through the light guide plate 8 is reflected toward the light emitting surface 14 by the groove 29 provided on the scattering surface 27 and is emitted from the light emitting surface 14.

  Next, the light 28 reflected by the groove 29 will be described with reference to FIG. The groove 29 has a reflecting surface 30, and the reflecting surface 30 has an angle of 1 to 35 degrees with respect to the scattering surface 27. The light 28 that has propagated through the light guide plate 8 is reflected by the reflecting surface 30 and changes its angle, whereby the angle with respect to the normal line of the light emitting surface 14 is reduced, and light can be emitted from the light emitting surface 14. In other words, as described above, the light 28 repeatedly undergoes total reflection in the light guide plate 8, but the light 28 is emitted from the light guide plate 8 at an angle at which the light 28 can be emitted by the reflection surface 30.

  A protrusion 31 is formed around the groove 29. The protrusion 31 is formed by removing a part of the light guide plate 8 pressed by the mold when the groove 29 is formed, and rising from the scattering surface 27 to the outside. Such protrusions 31 have the effect of expanding the effective area of the reflection surface 30 and preventing the light guide plate 8 and a reflection sheet 35 described later from being in close contact with each other, but are not necessarily essential.

  As shown in FIG. 4, prism sheets 32 and 33 are provided on the light emitting surface 14 of the light guide plate 8 to control the direction of the light 28 emitted from the light guide plate 8. In the figure, the prism sheets 32 and 33 are arranged so that the ridgelines of the triangular prism intersect. The prism sheet 32 refracts the traveling direction of the light 28 emitted from the light guide plate 8 in the vertical direction (left and right direction in the figure), and the prism sheet 33 refracts in the horizontal direction (front and rear direction in the figure) and directs it toward the liquid crystal panel. Reference numeral 34 denotes a diffusion plate, and reference numeral 35 denotes a reflection sheet.

  In addition, as shown with the broken line in the figure, you may provide the groove | channel 36 also in the light emission surface 14 of the light-guide plate 8. FIG. The groove 36 is formed in a direction orthogonal to the groove 29 and refracts the traveling direction of the light 28 to be emitted from the light guide plate 8 in the lateral direction (front-rear direction in the figure) and directs it toward the liquid crystal panel. When the light guide plate 8 has the grooves 36, the prism sheet 33 may be omitted.

  FIG. 5 is a perspective view of the vicinity of the incident surface 13 of the light guide plate 8. A lens surface 131 is provided on the incident surface 13 of the light guide plate 8. The lens surface 131 functions to scatter light incident from the incident surface 13. Light incident from the lens surface 131 is guided to the light emitting surface 14 through the inclined portion 15. Since the lens surfaces 131 are formed so as to be disposed in front of the light emitting diode 9 that is a light emitter, the same number of lens surfaces 131 as the light emitting diodes 9 are provided. However, the entire incident surface 13 may be used as the lens surface 131. Further, as shown in the figure, the lens formed on the lens surface 131 may be a so-called lenticular lens in which a plurality of cylindrical lenses are arranged, or other shapes, for example, a plurality of triangular prismatic protrusions are arranged. It may be in any shape, such as The incident surface 13, the lens surface 131, the inclined portion 15, and the like form a light incident portion 16.

  Further, the incident surface 13 is divided into a first surface 132 and a second surface 133 which are two surfaces extending in the longitudinal direction of the incident surface 13. In the drawing, the second surface 133 is hatched for easy distinction between the two. The first surface 132 occupies most of the incident surface 13 and has a small surface roughness and is smoothly finished. The first surface 132 is inclined by about 1 to 2 degrees with respect to the normal direction of the light emitting surface 14. On the other hand, the surface roughness of the second surface 133 is rougher than that of the first surface 132. Further, the width of the second surface 133 in the vertical direction is small, and is approximately 50 μm in this embodiment. However, the width is not particularly limited and is arbitrary. The second surface 133 is not particularly inclined, but the second surface 133 may have an inclination. The difference between the first surface 132 and the second surface 133 is caused by a process in which each surface is formed. As will be described in detail later, the first surface 132 is a thermal transfer surface formed in contact with the surface of the mold during thermal transfer, whereas the second surface 133 is a cut surface formed by cutting after thermal transfer. It is.

  FIG. 6 is a diagram showing the positional relationship of the first surface 132 and the second surface 133 with respect to the light emitting diode 9, and the light emitting diode 9 is added to the cross section taken along the line AA in FIG. The light emitted from the light emitting diode 9 is emitted from a specific range including the center to a region at a specific angle, not from the entire irradiation surface of the light emitting diode 9. In the figure, the irradiation region 37, which is the region irradiated with light from the light emitting diode 9, is indicated by hatching, and the boundary of the irradiation region 37 is indicated by a broken line. Even in the region on the irradiation surface side of the light emitting diode 9, the region outside the irradiation region 37 becomes a non-irradiation region 38 that is not irradiated with light.

  As shown in the drawing, the first surface 132 is provided so as to include the irradiation region 37. As described above, the first surface 132 has a small surface roughness, and efficiently guides the light emitted from the light emitting diode 9 to the inside of the light guide plate 8. Get higher. On the other hand, as described above, since the surface roughness of the second surface 133 is large and rough, the light irradiated on the surface of the second surface 133 is diffusely reflected and cannot be sufficiently guided into the light guide plate 8. Therefore, it is preferable to arrange the second surface 133 in the non-irradiation region 38. In the figure, for easy understanding, the inclined portion 15, the light emitting surface 14, and the scattering surface 27 are indicated by reference numerals.

  It continues and the manufacturing method of the light-guide plate 8 is demonstrated. FIG. 7 is a diagram schematically showing a process of manufacturing the light guide plate 8.

  First, as shown to (a) in a figure, the sheet | seat material 39 is prepared and heated (heating process). The material of the sheet material 39 is the same as that of the light guide plate 8, and the thickness thereof is substantially the same as the thickness of the light emitting surface 14 of the light guide plate 8. Moreover, the heating temperature should just be a temperature which becomes soft so that the sheet | seat material 39 can deform | transform. The sheet material 39 is disposed between the front surface mold 40 and the back surface mold 41. A material for forming the sheet material 39 is poured into the groove mold 4001 for forming the groove 36, the inclined concave portion 4002 for forming the inclined portion 15, and the inclined concave portion 4002 on the surface of the surface mold 40, and the first surface. A convex portion 4003 for forming 132 is formed. The surface of each part is processed so as to reduce the surface roughness by polishing or the like. A groove mold 4101 for forming the groove 29 is formed on the surface of the back surface mold 41. Similarly to the front surface mold 40, the surface of the back surface mold 41 is processed so that the surface roughness is reduced by polishing or the like.

  In the drawing, although one light guide plate 8 is manufactured from one sheet material 39, the present invention is not limited to this, and a plurality of light guide plates 8 are manufactured from one sheet material 39. You may do it. In that case, a plurality of patterns similar to those shown in the figure are formed on the surfaces of the front surface mold 40 and the back surface mold 41.

  Subsequently, as shown in FIG. 5B, the sheet material 39 is sandwiched between the front surface mold 40 and the back surface mold 41 and a pressure is applied (transfer process). As a result, the sheet material 39 is deformed, and a pattern complementary to the pattern formed on the surface of the front surface mold 40 and the back surface mold 41 is transferred to the surface. At this time, there is a slight gap between the convex portion 4003 of the front surface mold 40 and the upper surface 4102 of the back surface mold 41, and a connection portion 3901 formed by crushing the sheet material 39 is formed in this portion. Yes. Although the thickness of the connection portion 3901 may be arbitrary, in this embodiment, it is approximately 50 μm.

  Then, as shown in (c) in the figure, the front surface mold 40 and the back surface mold 41 are opened, and the sheet material 39 is taken out (peeling step). In this state, the connection portion 3901, the inclined convex portion 3902, and the groove forming portion 3904 are transferred and formed on the sheet material 39.

  And as shown in (d) in a figure, the sheet material 39 is cut out along the external shape of the light-guide plate 8 with the cutting blade 42 (cutting process). At this time, the connecting portion 3901 is cut off at the end of the inclined convex portion 3902 as shown in FIG. Thereby, the cut-out portion is obtained as the light guide plate 8. As a result, the inclined convex portion 3902 becomes the inclined portion 15, the surface of the groove forming portion 3904 becomes the light emitting surface 14, and the back surface becomes the scattering surface 27. Note that the cutting blade 42 is not particularly limited. A thin plate-like blade may be used, or a so-called punch that performs punching may be used. Alternatively, a roller cutter using a circular blade may be used.

  FIG. 8 is an enlarged view of portion B in FIG. In the same figure, angles and dimensions are exaggerated for easy understanding. As shown in the figure, a first surface 132 and a second surface 133 are formed on the incident surface 13 of the light guide plate 8. The first surface 132 is inclined at an angle θ with respect to the normal direction of the light emitting surface 14, and the direction of the inclination recedes from the second surface 133 as shown in the figure. It is a direction to do. This inclination is known as a so-called draft, and is necessary when the surface mold 40 that has bitten into the sheet material 39 is peeled from the sheet material 39 (see FIG. 7B). . The inclination angle θ is preferably between 1 degree and 2 degrees. This is because it is difficult to peel the surface mold 40 from the sheet material 39 at an angle smaller than 1 degree, and the light incident from the incident surface 13 is uniformly distributed over the entire light guide plate 8 at an angle larger than 2 degrees. It becomes difficult to guide. However, such an angle may be appropriately set according to the material and size of the light guide plate 8 and the shape of the groove 29. Further, as is clear from the above description, the first surface 132 is a surface formed when the material of the flowed sheet material 39 is in close contact with the side surface of the convex portion 4003 of the surface mold 40 (FIG. 7 (b)). In other words, the first surface 132 is a thermal transfer surface formed by thermal transfer. The surface roughness of the first surface 132 depends on the surface roughness of the side surface of the convex portion 4003 of the surface mold 40. When the surface roughness of the part is reduced by polishing or the like, the surface roughness of the first surface 132 is reduced. The surface roughness is reduced.

  On the other hand, the 2nd surface 133 is a surface formed when the connection part 3901 is cut | disconnected by the cutting blade 42 (refer FIG.7 (d)). In other words, the second surface 133 is a cut surface formed by cutting. Since the second surface 133 receives a shearing force when formed, even if the cutting blade 42 is sharp, it is difficult to make the surface roughness smaller than a certain limit. Therefore, the surface roughness of the second surface 133 is larger than the surface roughness of the first surface 132. The second surface 133 is ideally formed so as to be continuous with the first surface 132 as shown in FIG. 8, but from the end of the light guide plate 8, that is, in the left side of FIG. It may be slightly protruding in the direction.

  In the description so far, the second surface 133 is formed on the edge of the light emitting surface 14 on the back surface side (the side on which the scattering surface 27 is formed) of the light guide plate 8. The light guide plate 8 may be formed on the edge of the front surface side (the side where the light emitting surface 14 is formed).

  FIG. 9 is a diagram illustrating the light guide plate 8 in which the second surface 133 is formed on the edge of the front side of the light guide plate 8 (the side on which the light emitting surface 14 is formed). Also in this case, the first surface 132 is formed so as to be inclined in such a direction that the incident surface 13 is retracted as it is away from the second surface 133, and the inclination angle θ is the same as in the case of FIG. Preferably it is between 1 and 2 degrees.

  FIG. 10 is a diagram showing a mold for manufacturing the light guide plate 8 shown in FIG. In the figure, the same reference numerals are given to the parts common to FIG. The remarkable difference between the front surface mold 40 and the back surface mold 41 shown in FIG. 7 and the mold shown in FIG. 7A is that the convex portion 4103 is formed on the back surface mold 41 in the mold shown in FIG. And that the relief part 4004 for receiving the convex part 4103 and forming the connection part 3901 is formed in the surface mold 40. Other than that, there is no particular difference between the two.

  In the embodiment described above, the incident surface 13 is described as being provided on one side of the light guide plate 8. However, the present invention is not limited to this, and light may be incident from a plurality of sides of the light guide plate 8. In that case, the first surface 132 that is the thermal transfer surface may be formed on at least one surface that becomes the incident surface 13, but the first surface 132 may be formed on all surfaces that become the incident surface 13. preferable.

  In the present embodiment, among the side surfaces of the light guide plate 8, other side surfaces that are not the incident surface 13 are not particularly limited, but the first surface 132 that is a thermal transfer surface is also formed on these other side surfaces. You may do it.

  Further, in the present embodiment, the incident surface 13 has been described as including the first surface 132 and the second surface 133, but a surface other than the first surface 132 and the second surface 133 is formed on the incident surface 13. It does not prevent it from forming. As a form for carrying out the present invention, it is sufficient that the incident surface 13 includes at least the first surface 132 and the second surface 133.

  DESCRIPTION OF SYMBOLS 1 Liquid crystal display device, 2 Liquid crystal panel, 3 Backlight, 4 Control circuit, 5 Flexible board, 6 Wiring, 7 Terminal, 8 Light guide plate, 9 Light emitting diode, 10 Storage case, 11 Flexible board, 12 Wiring, 13 Incident surface, 14 light emitting surface, 15 inclined portion, 16 light incident portion, 17 TFT substrate, 18 color filter substrate, 19 pixel portion, 20 pixel electrode, 21 display area, 22 gate signal line, 23 drain signal line, 24 switching element, 25, 26 drive circuit, 27 scattering surface, 28 light, 29 groove, 30 reflection surface, 31 projection, 32, 33 prism sheet, 34 diffuser plate, 35 reflection sheet, 36 groove, 37 irradiation region, 38 non-irradiation region, 39 sheet material , 40 Surface mold, 41 Back mold, 42 Cutting blade, 131 Lens surface, 132 First surface, 13 Second surface, 901 LED chip, 902 chip substrate, 903 p electrode, 904 n electrode, 905 wire, 906 chip terminal, 907 fluorescent light emitting portion, 908 reflecting portion, 909 emitting surface, 3901 connecting portion, 3902 inclined convex portion 3903 Groove forming part, 4001 Groove type, 4002 Inclined concave part, 4003 Convex part, 4004 Escape part, 4101 Groove type, 4102 Upper surface, 4103 Convex part.

Claims (4)

LCD panel,
A backlight disposed on the back side of the liquid crystal panel, and having a light guide plate and a light emitter that enters light into an incident surface that is at least one side surface of the light guide plate;
Have
The liquid crystal display device, wherein the incident surface includes at least a first surface on which light from the light emitter is incident and a second surface having a surface roughness rougher than that of the first surface. The first surface and the second surface extend in the longitudinal direction of the incident surface,
The first surface is disposed so as to include an irradiation region irradiated with light from the light emitter,
The liquid crystal display device according to claim 1, wherein the second surface is disposed in a non-irradiation region where light from the issuer is not irradiated. The first surface and the second surface extend in the longitudinal direction of the incident surface,
The liquid crystal display device according to claim 1, wherein the second surface is provided on an edge of the light incident plate on the front surface side or the back surface side of the light incident surface.   The liquid crystal display device according to claim 1, wherein the first surface is inclined with respect to a normal direction of a surface of the light guide plate.

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