JP2010008682A - Liquid crystal display using lighting device - Google Patents

Abstract

There is provided a liquid crystal display device capable of favorably performing area control in which a display screen is divided into a plurality of regions.
A liquid crystal display device according to the present invention includes a lighting device having a light source K and a light guide plate 22 that diffuses the light of the light source K to be a surface light source, and has a liquid crystal layer disposed to face the lighting device. The light guide plate 22 includes a groove 2m that divides the entire display region G into divided regions r on the side opposite to the side on which the liquid crystal panel is disposed, and the light guide plate 22 includes a liquid crystal panel. 22 includes a reflecting member 23 that is disposed along the surface including the groove 2 m in 22 and reflects light emitted from the light guide plate 22.
[Selection] Figure 4

Description

  The present invention relates to a liquid crystal display device used for a television, a mobile phone and the like.

In recent years, liquid crystal display devices widely used in televisions, mobile phones, etc. are characterized by a short and thin depth as a flat panel display compared to conventional cathode ray tube type display devices that emit electron beams. It has become.
FIG. 11A is a front view of a conventional liquid crystal television 100, and FIGS. 11B and 11C illustrate a light guide plate 102 disposed on the back side of the display screen G in the conventional liquid crystal television 100. FIG. 3 is a conceptual front view showing a configuration of a light source k arranged on both outer sides of a display screen G. FIG.

  In order to make further use of this thin feature, the liquid crystal display device is a direct type system in which a light source that transmits light from the rear side of the conventional voltage-controlled liquid crystal panel 101 is disposed behind the display screen G (see FIG. 11A). On the other hand, recently, in order to further utilize the thin features, as shown in FIG. 11A, the light source k is arranged on both outer sides of the display screen G, and the light from the light sources k on both outer sides is emitted. A sidelight method is adopted in which light is diffused and diffusely reflected using the light guide plate 102 (see FIGS. 11B and 11C), etc., and the light is guided as a surface light source from the rear of the liquid crystal panel 101 (see FIG. 11A). ing.

  By the way, in the liquid crystal television 100 shown in FIG. 11A, the display screen G is vertically divided into a plurality of regions r, and as shown in FIG. 11C, a light source k and a light guide plate are provided for each region r. 102 is provided and managed, and by adjusting the brightness for each region r, area control is adopted to improve the contrast for each region r in accordance with the image data of each region r, or to improve the moving image performance of the liquid crystal television 100 It is being done. This area control has an advantage that power consumption can be reduced because the light source k is turned on for each region r.

For example, Patent Document 1 describes a technique for dividing the light guide plate 102 together with the light source k.
JP 2006-134748 A (FIG. 1 etc.)

By the way, as shown in FIG. 11B, when the light guide plate 102 is formed as a single piece, the light emitted from the light source k spreads in the light guide plate 102 as shown by the arrow α102 and in the display screen G. It is too wide and modulation for each region r is difficult to work. For this reason, it is difficult to adjust the brightness of an arbitrary region r of the liquid crystal panel 101 (see FIG. 11A).
On the other hand, as shown in FIG. 11C, the technique of Patent Document 1 is divided into the light guide plate 102, so that the light traveling in the light guide plate 102 has a refractive index with the air layer a <b> 1 outside the light guide plate 102. Due to the difference, the amount of light totally reflected on the surface of the light guide plate 102 (arrow α101 in FIG. 11C) is large, and the light guide plate 102 adjacent to each other through the light layer 102 and the air layer a1 at the boundary portion thereof. Little light leaks out. Therefore, the light emitted from the light source k does not spread in the display screen G (see FIG. 11A), and the modulation for each region r is likely to be effective, but the variation in the characteristics of each light source k is the brightness and color for each region r. There is a problem that it will appear as a variation of.

  Therefore, as shown in FIG. 12B of FIG. 12A and FIG. 12B of the cross-sectional view taken along the line HH in FIG. 12A, a groove portion 200m that divides the integrated light guide plate 202 into each region r is formed. It is conceivable that part of the light in one region r leaks to the adjacent region r through the connecting portion s that forms the groove 200m that connects the regions r. 12A is a front view showing a light guide plate 202 and a light source k in which a groove portion 200m divided into each region r is formed in a conventional integrated light guide plate 202, and FIG. FIG. 12C is an enlarged cross-sectional view taken along the line HH of FIG. 12A, and shows how light travels around the groove 200 m in the light guide plate 202.

  According to this configuration, the light from the light source k spreads in the light guide plate 202 to some extent, and modulation for each area (modulation for each region r) is effective, and the characteristic variation of the light source k in one region r in the light guide plate 202 is adjacent or nearby. By sharing the light with the region r, variations in brightness and color for each region r are offset, and variations in characteristics of each light source k are suppressed from becoming variations in brightness and color for each region r. effective.

  However, in the case of the light guide plate 202 in which the groove portion 200m shown in FIGS. 12A and 12B is formed, of the light emitted from the light source k and propagating through the light guide plate 202 and reaching the side surface 200m1 of the groove portion 200m, As shown in FIG. 12C, the light α200 that does not satisfy the total reflection condition at the side surface 200m1 of the groove 200m enters the groove 200m, and enters the light guide plate 202 again from the groove bottom 200m3 of the groove 200m. To do. Since the light α200 does not satisfy the total reflection condition at the interface 202k with the air layer on the display surface side of the light guide plate 202, the light α200 extends from the interface 202k of the connecting portion s to the display surface side (left side in FIG. 12C). Emitted.

Thus, since the light from the groove part 200m leaks from the interface 202k of the light guide plate 202, the light intensity emitted from the connecting part s to the display surface side is larger than that around the connecting part s, and the groove part 200m The connecting portion s of the formed portion is brighter than the peripheral portion thereof, and becomes a bright line of display unevenness (see the two-dot chain line in FIG. 11A) on the display screen G (see FIG. 11A). This causes a new problem of being visually observed.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a liquid crystal display device that can perform area control in which a display screen is divided into a plurality of areas without causing a viewer to feel uncomfortable.

  In order to achieve the above object, a liquid crystal display device according to the first aspect of the present invention includes a lighting device having a light source, a light guide plate that diffuses light from the light source and uses it as a surface light source, and a liquid crystal disposed facing the lighting device. The light guide plate includes a groove portion that divides the entire display region into divided regions on the side opposite to the side on which the liquid crystal panel is disposed, and the light guide plate includes: A reflection member is provided along the surface including the groove and reflects light emitted from the light guide plate.

  According to a second aspect of the present invention, there is provided a liquid crystal display device comprising: a lighting device having a light source and a light guide plate that diffuses light from the light source to be a surface light source; and a liquid crystal panel having a liquid crystal layer disposed facing the lighting device. The light guide plate includes a groove portion that divides the entire display region into divided regions on the side opposite to the side on which the liquid crystal panel is disposed, and along the surface including the groove portion in the light guide plate. A frame member is provided that has a reflecting surface that is disposed and reflects light emitted from the light guide plate.

  According to a third aspect of the present invention, there is provided a liquid crystal display device comprising: a lighting device having a light source and a light guide plate that diffuses light from the light source to form a surface light source; and a liquid crystal panel having a liquid crystal layer disposed facing the lighting device. The light guide plate has a groove portion that divides the entire display region into divided regions, and has a size smaller than the groove portion of the light guide plate and is the same as the light guide plate fitted in the groove portion or A transparent fitting member having substantially the same refractive index is provided.

  According to a fourth aspect of the present invention, there is provided a liquid crystal display device comprising: a lighting device having a light source and a light guide plate that diffuses light from the light source to form a surface light source; and a liquid crystal panel having a liquid crystal layer disposed facing the lighting device. The light guide plate includes a groove portion that divides the entire display region into divided regions on the side opposite to the side where the liquid crystal panel is disposed, and has a size smaller than the groove portion of the light guide plate. A fitting member is provided that is fitted in the groove portion and has a surface facing the groove portion formed on a reflection surface that reflects light emitted from the light guide plate.

  According to a fifth aspect of the present invention, there is provided a liquid crystal display device comprising: a lighting device having a light source and a light guide plate that diffuses light from the light source to be a surface light source; and a liquid crystal panel having a liquid crystal layer disposed facing the lighting device. The light guide plate includes a groove portion having a rectangular cross section in a short side direction that divides the entire region of the display screen into divided regions, and a corner portion formed by the groove side surface and the groove bottom surface. The radius of curvature is greater than 0 and 50 μm or less, and the arithmetic mean roughness of the groove surface including the groove side surface and the groove bottom surface that forms the groove is greater than 0 and 15 nm (nanometers) or less.

  According to a sixth aspect of the present invention, there is provided a liquid crystal display device comprising: a lighting device having a light source and a light guide plate that diffuses light from the light source to be a surface light source; and a liquid crystal panel having a liquid crystal layer disposed facing the lighting device. The light guide plate is provided with a plurality of through holes or half through holes that form a boundary between the divided regions that divides the entire display region into a plurality of divided regions.

  ADVANTAGE OF THE INVENTION According to this invention, the liquid crystal display device which can perform the area control which divided | segmented the inside of a display screen into several area | region favorable is realizable.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
<< First Embodiment >>
<Overall configuration of LCD TV 10>
FIG. 1A is a front view of the liquid crystal television 10 according to the first embodiment of the present invention, and FIG. 1B is an enlarged cross-sectional view taken along line AA of FIG.
As shown in FIG. 1A, the liquid crystal television 10 to which the present invention is applied has a display screen G for displaying an image. When displaying an image on the display screen G, a voltage corresponding to the image is displayed. The light that transmits light from the rear (back side of the paper in FIG. 1 (a)) to the front (front side of the paper in FIG. 1 (a)) and adds intensity according to the image is fixed to the liquid crystal layer to which the color filter is applied. The image is displayed by irradiating each pixel and displaying a color corresponding to the image on each pixel.
FIG. 2A is a perspective view seen from obliquely above showing a state in which the main part of the structure for displaying an image on the display screen G shown in FIG. 1B is disassembled, and FIG. It is a BB line sectional enlarged view of 1 (a).

  As shown in FIGS. 1B and 2, the liquid crystal television 10 is configured to display an image on a display screen G, and is colored by a liquid crystal layer to which a voltage corresponding to the image is applied and light transmitted through the liquid crystal layer. Liquid crystal panel 1 having a color filter having a pixel to be used, and a light emitting diode (LED: Light Emitting Diode) which is disposed on both sides and mounted on a circuit board, and transmits light transmitted through liquid crystal panel 1 in the direction of arrow α0. The light source module K of the emitted light source, the light guide plate 2 that takes in the light from the light source module K and guides the light, and diffusely reflects the light that is printed on the back surface of the light guide plate 2 and is guided in the light guide plate 2 By doing so, light scattering dots d (see FIG. 2 (b)) such as a white printed dot pattern for guiding light forward as indicated by arrow α1, and the back side of the light guide plate 2 (see FIG. 1 (b)). All of the light guide plate rear surface 2r disposed on the lower side of the light plate 2) The light that has passed through the light guide plate 2 and the reflection member 3 for making the light escaped to the back side of the light guide plate 2 out of the reflection condition diffusely reflected into the light forward (in the direction of the arrow α1 in FIG. 1B). Is provided with an optical sheet 4 that makes the light uniform forward (in the direction of arrow α1 in FIG. 1B), and a frame member 5 that supports the light guide plate 2, the reflecting member 3, and the like.

Here, the light source module K that is a light source and the light guide plate 2 that guides light from the light source module K irradiates the liquid crystal panel 1 with light, and are therefore referred to as illumination devices.
In FIGS. 1B and 2B, a transparent front panel P (FIG. 2A) disposed on the front outer side of the liquid crystal panel 1 (the surface side of the paper surface of FIG. 1A). )) Is omitted.
As shown in FIG. 1B, the liquid crystal television 10 is engaged with the front case 9m made of resin in which an opening for forming the display screen G is formed, and the front case 9m is screwed. A rear housing case 9u, and a control device 8a for comprehensively controlling the liquid crystal television 10 on the rear housing case 9u, and a DC for setting the supplied voltage to an appropriate power supply voltage. / DC power supply 8b.

  The control device 8a is a device that controls the liquid crystal panel 1, the light source module K, and the like, and processes an image displayed on the liquid crystal television 10, for example, a CPU (Central Processing Unit), a RAM (Random Access) not shown. The liquid crystal television 10 is comprehensively controlled by executing a program stored in the ROM, which includes a microcomputer having a memory (ROM), a ROM (read only memory), and peripheral circuits.

<Light source module K>
3A is a front view showing the light guide plate 2, the light source modules K (K11,..., K17, K21,..., K27) and the like, and FIG. FIG.
Corresponding to the seven areas r (r1, r2,..., R7) dividing the display screen G shown in FIG. 1 (a), as shown in FIG. 2 (a) and FIG. In total, 14 light source modules K are provided to face each other.
As shown in FIG. 1B, both side surfaces of the light guide plate 2 on which light from the light source module K enters the light guide plate 2 are referred to as incident surfaces 2N, and light is directed from the light guide plate 2 toward the liquid crystal panel 1. The surface of the light guide plate 2 that exits is referred to as an exit surface 2D.

Each of the light source modules K (K11,..., K17, K21,..., K27) is mounted with a plurality of red, blue, and green light emitting diodes d, and the light emitted from the light emitting diodes d of each light source module K is The light guide plate 2 is configured to be incident on the incident surface 2N.
Each of these light source modules K (K11,..., K27) controls brightness for each region r of the light guide plate 2 and controls to emphasize any one of the red, blue, and green light emitting diodes d. Independent area control is performed by the control device 8a for each region r, such as control for emphasizing the light emitting diodes d of one color. The light intensity of the light source module K (K11,..., K27) is controlled by the applied current level.

<Light guide plate 2>
The light guide plate 2 shown in FIGS. 1B and 2A is a transparent plate formed of a resin such as an acrylic resin, for example, and as shown in FIG. It is divided into divided areas r (r1, r2,..., R7). And each area | region r of the light-guide plate 2 is connected via the connection part S which opposes this groove part m, and one integral light-guide plate is formed.
The display screen G (see FIG. 1A) is vertically formed by a groove m formed on the back surface 2r side of the light guide plate 2 shown in FIG. 3B, that is, on the side opposite to the side where the liquid crystal panel 1 is disposed. It is divided into regions r (r1, r2,..., R7) divided into seven in the direction.

<Width dimension s1 of groove part m of light guide plate 2>
As shown in FIG. 3B, the groove portion m in the light guide plate 2 has a rectangular shape in the short side direction of the light guide plate 2, and the width dimension s1 of the rectangle is larger than 0 and 0. .5mm or less.
By setting the width dimension s1 to be larger than 0 and narrower to 0.5 mm or less, as shown in FIG. 3B, the light α11 emitted from the light source module K and transmitted through the light guide plate 2 is generated in the groove m. On the other hand, the light is emitted from the groove side surface m1 and travels in the groove part m to reach the other groove side surface m2 of the groove part m on the opposite side. The light α11 that has reached the other groove side surface m2 travels again in the light guide plate 2 and is reflected to satisfy the total reflection condition at the interface 2k with the air of the emission surface 2D on the display surface side, and is reflected on the display surface side, that is, the emission surface. The light α12 propagates through the light guide plate 2 again without being emitted outward in 2D.
Therefore, the light emission from the exit surface 2D facing the groove portion m in the light guide plate 2 is prevented from being emitted, and the portion facing the groove portion m on the display screen G (see FIG. 1A) is visually recognized as a bright line. It can be suppressed.

  On the other hand, as shown in FIG. 12 (c), when the width dimension s200 of the groove 200m is larger than 0.5 mm, the light α200 traveling through the light guide plate 202 through the groove 200m is Since the total reflection condition is not satisfied at the interface 202k with the air on the display surface facing the groove 200m, the light passing through the groove 200m is transmitted through the light guide plate 202 and the display surface side from the interface 202k (FIG. 12C). To the left). Therefore, on the display screen G shown in FIG. 11A, the boundary between the regions r, that is, the portion facing the groove 200m is viewed brightly by the viewer as a bright line.

<Angle θ1, θ2 formed by groove bottom surface m3 of groove portion m of light guide plate 2 and groove side surfaces m1, m2>
The angle θ1 of the groove side surface m1 with the groove bottom surface m3 in the groove portion m shown in FIG. 3B as the reference plane is optimally 90 degrees, and desirably within 90 degrees ± 1 degree.
Similarly, the angle θ2 of the other groove side surface m2 with the groove bottom surface m3 in the groove portion m shown in FIG. 3B as the reference surface is optimally 90 degrees, and desirably within 90 degrees ± 1 degree.
By setting the angles θ1 and θ2 to within 90 ° ± 1 °, the light source module K emits from the light guide plate 2 to the groove portion m via the groove side surfaces m1 and m2, and again the groove bottom surface m3 of the groove portion m. The light traveling from the light guide plate 2 to the light guide plate 2 can satisfy the total reflection condition at the interface 2k (exit surface 2D) with the air on the display surface side of the light guide plate 2. For this reason, it is possible to suppress the boundary area between the regions r in the display screen G (see FIG. 1A), that is, the portion facing the groove portion m of the light guide plate 2 from being viewed brightly by the viewer as a bright line. .

  On the other hand, for example, in FIG. 12C, the angles θ1 and θ2 of the groove side surfaces 200m1 and 200m2 with the groove bottom surface 200m3 of the groove portion 200m as the reference plane are out of the range of 90 ° ± 1 °, respectively. In this case, light emitted from the light source k and traveling from the inside of the light guide plate 2 into the groove portion 200m through the groove side surfaces 200m1 and 200m2 and traveling through the light guide plate 2 from the groove bottom surface 200m3 of the groove portion 200m is guided by the light guide plate 202. The number of cases where the total reflection condition is not satisfied at the interface 202k with the air on the display surface side in FIG. 11 increases, and the boundary between the regions r in the display screen G shown in FIG. 11A (location facing the groove portion 200m of the light guide plate) Is viewed as a bright bright line locally by the viewer.

<Curves of corners c1 and c2 between the groove bottom m3 of the light guide plate 2 and the groove side surfaces m1 and m2>
The curvature radius R1 of the corner c1 between the groove bottom surface m3 and the one groove side surface m1 in the cross section in the short side direction of the light guide plate 2 of the groove portion m of the light guide plate 2 shown in FIG. 3B is set to be larger than 0 and 50 μm or less. is doing.
That is, 0 <curvature radius R1 ≦ 50 μm of the corner c1.
Similarly, the radius of curvature R2 of the corner portion c2 between the groove bottom surface m3 and the other groove side surface m2 in the cross section in the short side direction of the light guide plate 2 of the groove portion m in the light guide plate 2 is set to be greater than 0 and 50 μm or less.
That is, 0 <the radius of curvature R2 of the corner portion c2 ≦ 50 μm.

This is because, when the radius of curvature of the corners c1 and c2 of the groove m exceeds 50 μm, the light that travels through the light guide plate 2 and is reflected by the corners c1 and c2 The number of cases where the total reflection condition is not satisfied at the interface 2k) increases, and the portions corresponding to the corners c1 and c2 of the groove portion m of the light guide plate 2 on the display screen G (see FIG. 1A) shine. Will be visually observed.
However, by setting the radii of curvature R1 and R2 of the corners c1 and c2 of the groove part m to be larger than 0 and 50 μm or less, the light traveling through the light guide plate 2 and reflected by the corners c1 and c2 is emitted from the exit surface 2D (display). The number of cases where the total reflection condition is not satisfied at the interface 2k) with the air on the surface side can be reduced, and the portions corresponding to the corners c1 and c2 of the groove m on the display screen G (see FIG. 1) are visually observed as bright lines. Can be suppressed.

<Surface roughness of the groove surface of the groove part m of the light guide plate 2>
The surface roughness Ra (arithmetic mean roughness) of the groove surface including both the groove side surfaces m1 and m2 and the groove bottom surface m3 forming the groove portion m shown in FIG. 3B is set to be larger than 0 and 15 nm (nanometer) or less. is doing.
When the surface roughness Ra of the groove surface of the groove part m is rough, light is scattered on the groove surface, and the groove part m is shined on the display screen G (see FIG. 1A) and is visually observed as a bright line.
By making the surface roughness Ra of the groove surface of the groove portion m greater than 0 and not more than 15 nm, light scattering on the groove surface is prevented, which corresponds to the groove portion m in the display screen G (see FIG. 1A). It can suppress that a part becomes a bright line.

<Frame member 5>
The frame member 5 is a strength member that structurally supports the light guide plate 2 or the like that is not necessarily strong in strength. For example, a steel plate having a thickness of 1 mm is used.
Here, the light guide plate 2 is a resin such as a thin plate acrylic resin having a wide surface (see FIGS. 1B and 2) extending opposite to the display screen G (see FIG. 1A). It is a member made of steel and needs to be structurally reinforced. Therefore, the frame member 5 plays a role of reinforcing the light guide plate 2.
As the frame member 5, an aluminum plate having excellent mechanical properties and good workability is used in addition to the steel plate.

<Effect>
According to the structure of the said 1st Embodiment, the cross section of the short side direction of the light-guide plate 2 is on the non-display surface side by the side of the non-liquid crystal panel 1 in the light-guide plate 2, ie, the opposite side to the side where the liquid crystal panel 1 is arrange | positioned. Since the rectangular groove portion m is formed and the width dimension s1 of the groove portion m is set to be larger than 0 and equal to or less than 0.5 mm, the light source module K emits the light guide plate 2 as shown in FIG. The light α11 is emitted from one groove side surface m1 in the groove portion m, proceeds into the groove portion m, and reaches the other groove side surface m2 on the opposite side, so that the light guide plate 2 in the display screen G (see FIG. 1A). The portion corresponding to the groove portion m can be suppressed from being viewed by the viewer as a bright bright line locally. The light source module K is disposed on the front side and the back side in FIG. 3B (see FIG. 3A).

  Further, the angles θ1 and θ2 formed between the groove bottom m3 of the groove part m of the light guide plate 2 and the one groove side face m1 and the other groove side face m2 are set within 90 ° ± 1 degree, respectively, so that the groove side m1 and m2 are within the groove part m. In the display screen G (see FIG. 1 (a)), the portion corresponding to the groove portion m of the light guide plate 2 can be suppressed by the exit surface 2D that leaks into the light guide plate 2 and faces the groove portion m of the light guide plate 2 However, it can be suppressed that the viewer visually recognizes the bright bright line locally.

In addition, since the curvature radii of the corners c1 and c2 of the groove bottom m3 and the groove side surfaces m1 and m2 of the groove part m of the light guide plate 2 are set to be larger than 0 and 50 μm or less, they are reflected by the corners c1 and c2 and emitted. The amount of light that does not satisfy the total reflection condition on the surface 2D is reduced, and the portions corresponding to the corners c1 and c2 on the display screen G (see FIG. 1A) are suppressed from being illuminated and visually observed.
Further, since the surface roughness Ra (arithmetic mean roughness) of the groove surface including the groove side surfaces m1 and m2 and the groove bottom surface m3 forming the groove portion m of the light guide plate 2 is set to be larger than 0 and 15 nm (nanometer) or less, The amount of light scattered on the groove surface can be reduced, and the portion corresponding to the groove portion m of the light guide plate 2 can be viewed as a bright bright line locally by the viewer on the display screen G (see FIG. 1A). Can be suppressed.

From the above, in the display screen G (see FIG. 1A), light leakage from one region r to the adjacent or neighboring region r can be appropriately performed, and light is shared in the neighboring region. Area control for independently controlling the light source module K for each region r (see FIG. 1A) can be performed by reducing color unevenness and brightness unevenness for each region r of the display screen G, and between the regions r. Bright lines can be suppressed as much as possible, and high-quality display is possible.
Further, the area control can reduce the power consumption of the liquid crystal television 10.

  In the first embodiment, (1) the width dimension s1 of the groove portion m is greater than 0 and equal to or less than 0.5 mm, and (2) the angle formed between the groove bottom surface m3 of the groove portion m of the light guide plate 2 and the groove side surfaces m1 and m2. θ1 and θ2 are within 90 ° ± 1 °, and (3) the radius of curvature of each of the corners c1 and c2 of the groove bottom m3 and the groove side surfaces m1 and m2 of the light guide plate 2 is greater than 0 and 50 μm or less ( 4) Although the case where the surface roughness Ra (arithmetic average roughness) of the groove surface of the groove portion m of the light guide plate 2 is set to be greater than 0 and 15 nm or less is illustrated, any of these four configurations (1) to (4) It is also possible to select one or at least two of the four configurations (1) to (4) as appropriate, and in these cases, each of the four configurations Each said effect is show | played similarly.

  Further, in the first embodiment, the case where the groove portion m of the light guide plate 2 is provided on the non-display surface side that is the non-liquid crystal panel 1 side is illustrated (see FIG. 3B), but the display on the liquid crystal panel 1 side is illustrated. It can also be provided on the surface side. In this case, the optical sheet 4 may be disposed away from the light guide plate 2 to improve the discreteness of the light emitted from the light guide plate 2.

<< Second Embodiment >>
Next, the liquid crystal television of the second embodiment will be described with reference to FIG. FIG. 4 is an enlarged cross-sectional view taken along line CC of the light guide plate and the like shown in FIG. 3A of the first embodiment in the second embodiment.
As shown in FIG. 4, the light guide plate 22 of the second embodiment has a display screen G (see FIG. 1A) on the back surface 22r, that is, the surface opposite to the side where the liquid crystal panel is arranged. The light guide plate 22 divided into regions r is provided with a concave groove 2m having a rectangular cross section in the short side direction, and a convex portion 25t that is inserted into the concave groove 2m of the light guide plate 22 is formed in the frame member 25. Yes.
As shown in FIG. 4, the reflecting member 23 is arranged along the back surface 22 r including the groove portion 2 m of the light guide plate 22 and along the frame member 25 having the convex portion 25 t.

A conical light extraction groove 22s is formed on the back surface 22r of the light guide plate 22 by injection molding or the like. When light emitted from the light source module K and guided through the light guide plate 2 is reflected by the light extraction groove 22s, the light exit surface 22D of the light guide plate 22 does not satisfy the total reflection condition and is extracted to the liquid crystal panel 1 side. An image is displayed by light.
The shape of the light extraction groove 22s may be selected as long as light is supplied to the liquid crystal panel side.

As the reflecting member 23, a reflecting sheet having a reflectivity of 85 to 99% is used, and a specular reflecting member, a diffuse reflecting member, or the like is used, and a specular reflecting member is most desirable. Note that when the reflection member 23 has a reflectance of less than 85%, the light is absorbed and the light utilization efficiency is lowered.
The frame member 25 does not play an optical role when the reflection member 23 having a reflectance of 85 to 99% is used, and any material can be selected.
However, since the frame member 25 plays a role of a strength member such as the light guide plate 22, it is preferable that the frame member 25 has a predetermined strength. For example, a low-cost steel plate or the like is used.

Further, the frame flat plate 25h and the convex portion 25t in the frame member 25 may be integrally formed as the frame member 25, or both are manufactured as separate members, and the convex portion 25t is screwed to the frame flat plate 25h and fixed by welding or the like. Then, the frame member 25 may be formed. The convex portion 25t of the frame member 25 also plays a role of fixing the light guide plate 22.
Since the configuration other than this is the same as that of the first embodiment, the same components as those of the first embodiment are denoted by reference numerals in the 20th order, and detailed description thereof is omitted.

<Effect>
According to the configuration of the second embodiment, as shown in FIG. 4, the width of the air layer formed in the groove 2 m of the light guide plate 22 can be reduced, and the reflection along the convex portion 25 t of the frame member 25. Since the light emitted from the light guide plate 22 is reflected by the member 23, the light that does not satisfy the total reflection condition can be suppressed at the emission surface 22D in the region facing the groove 2m of the light guide plate 22, and the display screen G (FIG. ))), The boundary between the regions r can be suppressed from being visually recognized as bright lines.

The frame member 25 may itself be configured as the reflecting member 23. For example, aluminum is vapor-deposited on the surface of the resin-molded frame member 25, and an aluminum layer is formed on the surface to serve as the reflecting member. It may be used also.
Alternatively, the frame member 25 itself may be made of aluminum, the surface may be mirror-finished, and the frame member 25 may also serve as a reflecting member.
In these cases, the reflecting member 23 is naturally unnecessary.

  In addition, in 2nd Embodiment, although the cross section of the short side direction of the light-guide plate 22 illustrated and demonstrated the groove part 2m (refer FIG. 4) of a rectangular shape, a curvature is made into the cross-sectional triangle shape or the back | inner side of a cross-sectional shape. The shape of the groove 2m, such as a semicircular shape or a semielliptical shape, can be selected as appropriate.

<< Third Embodiment >>
Next, a liquid crystal television according to a third embodiment will be described with reference to FIG. FIG. 5 is an enlarged cross-sectional view taken along line CC of the light guide plate and the like shown in FIG. 3A of the first embodiment in the third embodiment.
As shown in FIG. 5, the light guide plate 32 of the liquid crystal television of the third embodiment has a display screen G (see FIG. 1A) on the back surface 32r, that is, the surface opposite to the side on which the liquid crystal panel is disposed. ) Are divided into regions r, and a groove portion 3m having a concave portion with a concave cross section in the short side direction is provided, and a transparent insertion light guide member 36 having a slightly smaller dimension substantially the same as the groove portion 3m is provided as a groove portion. It fits in 3m.
In this case, the width dimension s31 of the groove 3m of the light guide plate 32 can be appropriately selected.

The transparent insertion light guide member 36 has the same material as or substantially the same refractive index as the light guide plate 32. For example, when the light guide plate 32 is formed of a transparent acrylic resin, the insertion light guide member 36 is also formed of a transparent acrylic resin.
Here, a clearance is formed between the groove surface forming the groove 3m of the light guide plate 32 and the insertion light guide member 36, and an air layer is formed in this clearance.

Further, since the insertion light guide member 36 having the same shape as the groove 3m is fitted into the groove 3m on the back surface 32r side of the light guide plate 32, the back surface 32r of the light guide plate 32 is formed on substantially the same surface, and the light scattering dots d are white. It is possible to print using ink.
Since the configuration other than this is the same as that of the first embodiment, the same components as those of the first embodiment are denoted by reference numerals in the thirties and detailed description thereof is omitted.

<Effect>
According to the configuration of the third embodiment, as shown in FIG. 5, the light α31 emitted from the light source module K and traveling in the light guide plate 32 is emitted from the groove side surface 3m1 of the groove portion 3m of the light guide plate 32 and guided. After the air layer having the clearance between the groove portion 3m of the optical plate 32 and the insertion light guide member 36 travels as light α32, the light enters the insertion light guide member 36 as light α33 and does not reach the groove bottom surface 3m3 of the groove portion 3m. After being totally reflected by the top surface 36 a of the optical member 36, further proceeding through the insertion light guide member 36, it is emitted from one outer surface of the insertion light guide member 36, and the groove portion 3 m between the insertion light guide member 36 and the light guide plate 32. After traveling through the air layer of the clearance as light α34, the light enters again from the groove side surface 3m2 of the groove 3m and travels through the light guide plate 32 as light α35.

  Therefore, when the insertion light guide member 36 is not provided, the light exiting from the exit surface 32D to the display surface side does not satisfy the total reflection condition at the exit surface 32D facing the groove 3m (see FIG. 12C). 5, the light α33 shown in FIG. 5 is totally reflected at the interface between the insertion light guide member 36 fitted in the groove 3m and the air, and thus corresponds to the groove 3m in the display screen G (see FIG. 1A). It can suppress that the part to do is visually recognized by a viewer as a bright bright line locally.

<Modification of Third Embodiment>
Next, a liquid crystal television of a modification of the third embodiment will be described with reference to FIG.
FIG. 6 is an enlarged cross-sectional view taken along the line C-C of the light guide plate and the like shown in FIG. 3A of the first embodiment in a modification of the third embodiment.
The light guide plate 32 'of the liquid crystal television of the modification of the third embodiment has an insertion guide fitted in a groove 3m' formed on the back surface 32r 'side, that is, the side opposite to the side on which the liquid crystal panel is disposed. The resin 3J ′ having the same or substantially the same refractive index as that of the light guide plate 32 ′ is poured into the gap between the optical member 36 ′ and the groove side surface 3m1 ′ and the groove bottom surface 3m3 ′ on one side of the groove 3m ′, and cured. It is.

For example, when the light guide plate 32 ′ is formed of an acrylic resin, the acrylic resin for the resin 3J ′ is dissolved in a solvent, and the groove side surface 3m1 ′ on one side of the groove portion 3m ′ of the insertion light guide member 36 ′ and the light guide plate 32 ′. The resin 3J 'is formed by pouring into each gap between the bottom surface 3m3' and evaporating and curing the solvent.
Alternatively, a double-sided adhesive tape made of acrylic resin is attached to both sides of the groove 3m ′ of the light guide plate 32 ′ of the insertion light guide member 36 ′ facing the groove side surface 3m1 ′ and the groove bottom surface 3m3 ′. As shown in FIG. 6, the insertion light guide member 36 'affixed to the two surfaces is adhered to the groove side surface 3m1' and the groove bottom surface 3m3 'of the groove 3m' of the light guide plate 32 'to form a resin 3J'. It is good.

<Effect>
According to the configuration of the modified embodiment, as shown in FIG. 6, the light α3 ′ emitted from the light source module and traveling through the light guide plate 32 ′ passes through the resin 3J ′ and the insertion light guide member 36 ′, and again, Since the light guide plate 32 'is advanced, the generation of light that does not satisfy the total reflection condition can be reduced at the emission surface 32D' facing the groove 3m '. Therefore, it can suppress that the location facing the groove part 3m 'is visually recognized as a bright line on the display screen G (refer Fig.1 (a)).
Further, since the insertion light guide member 36 ′ is fixed to the groove 3m ′ of the light guide plate 32 ′ via the resin 3J ′, a stable structure of the light guide plate 32 ′ and the insertion light guide member 36 ′ can be obtained.

  In this modification, the inserted light guide member 36 'is a resin 3J having the same or substantially the same refractive index on the two sides of the groove side surface 3m1' and the groove bottom surface 3m3 'of the groove 3m' of the light guide plate 32 '. Although the case of fixing with ′ is illustrated, the resin 3J ′ having the same or substantially the same refractive index may be fixed only to the groove side surface 3m1 ′ on one side of the groove portion 3m ′ of the light guide plate 32 ′.

  In the third embodiment (see FIG. 5) and a modification of the third embodiment (see FIG. 6), the grooves 3m and 3m ′ are formed on the non-display surface side where the reflecting members 33 and 33 ′ are arranged, respectively. However, it may be formed on the display surface side where the liquid crystal panel and the optical sheets 34 and 34 ′ are arranged. When the groove portions 3m, 3m ′ are formed on the display surface side where the liquid crystal panel, the optical sheets 34, 34 ′, etc. are arranged, the optical sheets 34, 34 ′ are arranged apart from the light guide plates 32, 32 ′. , 32 ′ may improve the discreteness of the light emitted toward the optical sheets 34, 34 ′.

<< Fourth Embodiment >>
Next, a liquid crystal television according to a fourth embodiment will be described with reference to FIG. FIG. 7 is an enlarged cross-sectional view taken along the line CC of the light guide plate and the like shown in FIG. 3A of the first embodiment in the fourth embodiment.
As shown in FIG. 7, the liquid crystal television of the fourth embodiment is non-transparent having the same small dimensions as the groove 4 m of the light guide plate 42 instead of the insertion light guide member 36 of the third embodiment shown in FIG. 5. The non-transparent highly reflective insertion light guide member 46 having a high surface reflectance is fitted into the groove 4m of the light guide plate 42.

In the fourth embodiment, the width of the air layer of the groove 4m of the light guide plate 42 is reduced, and the bright lines generated on the display screen G (see FIG. 1A) are suppressed.
As the non-transparent high reflection insertion light guide member 46 shown in FIG. 7, the surface of an aluminum rod is polished and mirror-finished, or the aluminum layer is formed by vapor-depositing aluminum on the surface of some rod-like member such as plastic or iron Etc. are used.

Further, the light guide plate 42 of the fourth embodiment has a conical light extraction groove 42s formed on the back surface 42r thereof by injection molding or the like instead of the light scattering dots d shown in FIG.
Since the configuration other than this is the same as the configuration of the third embodiment shown in FIG. 5, the same components are denoted by reference numerals in the 40s, and detailed description thereof is omitted.

<Effect>
According to the configuration of the fourth embodiment, as shown in FIG. 7, the light α41 emitted from the light source module K and traveling through the light guide plate 42 is emitted from the groove side surface 4m1 of the groove portion 4m, and the emitted light α42 is reflected by one surface of the non-transparent highly reflective insertion light-guiding member 46, enters the light guide plate 42 again from the groove side surface 4m1 of the groove 4m, and becomes light α43 traveling in the light guide plate 42.
Thereby, when there is no non-transparent highly reflective insertion light guide member 46, the light that does not satisfy the total reflection condition at the position of the emission surface 42D that travels in the light guide plate 42 and faces the groove 4m of the light guide plate 42 is It is reflected and returned by one surface of the reflection insertion light guide member 46. Therefore, it can suppress that the location facing the groove part 4m of the light-guide plate 42 of the display screen G (refer FIG. 1 (a)) is visually observed as a bright bright line locally.

<Modification of Fourth Embodiment>
Next, a liquid crystal television of a modification of the fourth embodiment will be described with reference to FIG. FIG. 8 is an enlarged cross-sectional view taken along the line C-C of the light guide plate and the like shown in FIG. 3A of the first embodiment in a modification of the fourth embodiment.
In the liquid crystal television of the modification of the fourth embodiment, resin 4J ′ is poured into the gap between the groove 4m ′ of the light guide plate 42 ′ of the fourth embodiment shown in FIG. 7 and the non-transparent highly reflective insertion light guide member 46 ′. It has been cured. As the resin 4J ′, a silicone resin, an acrylic resin, or the like can be used. Moreover, you may use a double-sided tape as resin 4J '.

<Effect>
According to the configuration of the above-described modification, the non-transparent highly reflective insertion light guide member 46 ′ is fixed to the groove 4m ′ of the light guide plate 42 ′ by the resin 4J ′. A stable structure fixed to the light guide plate 42 'can be obtained.
In this modification, the configuration in which the resin 4J is filled in all the gaps between the groove 4m ′ of the light guide plate 42 ′ and the non-transparent highly reflective insertion light guide member 46 ′ is illustrated. However, the groove 4m of the light guide plate 42 ′ is illustrated. It is good also as a structure filled with resin 4J for fixation in a part of clearance gap between 'and a non-transparent highly reflective insertion light guide member 46'.

  In the fourth embodiment (see FIG. 7) and the modified form of the fourth embodiment (see FIG. 8), the grooves 4m and 4m ′ have a rectangular cross section in the short side direction of the light guide plate 42 ′. However, the shape of the groove portions 4m and 4m ′ can be selected as appropriate, such as a triangular cross section or a semicircular shape or a semielliptical shape having a curvature on the back side of the cross sectional shape. When the grooves 4m and 4m ′ (see FIGS. 7 and 8) have a shape other than a rectangular cross section, the non-transparent high-reflection insertion light guide members 46 and 46 ′ have the cross sections of the grooves 4m and 4m ′, respectively. It will form in the shape along a shape.

<< Fifth Embodiment >>
Next, a liquid crystal television according to a fifth embodiment will be described with reference to FIGS.
9A is a front view showing the light guide plate 52, the light source module K, and the like of the fifth embodiment, and FIG. 9B is a cross-sectional enlarged view taken along the line DD in FIG. 9A. FIG. 9C is an enlarged cross-sectional view taken along the line EE of FIG. 9A.
As shown in FIG. 9 (a), the liquid crystal television of the fifth embodiment has a large number of fine through holes h in the light guide plate as boundaries that divide the display screen G (see FIG. 1 (a)) into regions r. (See FIGS. 9 (b) and 9 (c)).

FIG. 10 is an enlarged view of the F part in FIG. 9A, and is a view showing a typical way of the light α5 emitted from the light source module K in the light guide plate 52 of the fifth embodiment.
As shown in FIG. 10, the light α5 emitted from the light source module K and traveling in one region r6 in the light guide plate 52 is totally reflected at the interface h0 with the through hole h and travels again in the same region r6.
On the other hand, the light β5 emitted from the light source module K and traveling through the region r6 in the light guide plate 52 and traveling between the through holes h and h leaks into the adjacent region r7 and travels through the adjacent region r7. .
From the above, it is possible to control the amount of light that travels in the light guide plate 52 to the adjacent region r by the pitch dimension p of the through holes h.

The shape of the through hole h is preferably a rectangle or a square shown in FIG. In addition, when the shape of the through-hole h is a round hole, the amount of light leakage becomes excessive.
When the width dimension s51 of the through hole h is large, the amount of light leakage from the interface h0 to the through hole h increases, and the boundary of the region r on the display screen G (see FIG. 1A) is a bright line. As visible. For this reason, the width dimension s51 of the through hole h is preferably narrow, and by setting the width dimension s51 to be larger than 0 and 0.5 mm or less, bright lines can be suppressed.

As a suitable dimension of the through-hole h that allows area control of divided display for each region r and can suppress variations in brightness and color for each region r,
0 <width dimension s51 ≦ 0.5 mm of through hole h, 0 <length dimension s52 ≦ 10 mm,
0 <pitch dimension p ≦ 20mm
Is desirable.
As a method of forming the through hole h, it is possible to drill a through hole having a width of 0.3 mm by using a laser cutter.

<Effect>
According to the configuration of the fifth embodiment, since the through hole h is formed as a boundary that divides the region r, the light is discrete even when light traveling in the light guide plate 52 leaks into the through hole h. Become. Further, when this light passes through the optical sheet on the display surface side from the light guide plate 52, it becomes further discrete light, and the boundary between the regions r (see FIG. 1) on the display screen G (see FIG. 1A). It is possible to prevent the viewer from seeing the two-dot chain line in the display screen G as a bright line.

  In the fifth embodiment, the display screen G (see FIG. 1A) is described as an example of the through hole h as a hole dividing the region r. However, the display screen G is formed in a semi-through hole that does not penetrate the light guide plate 52. May be. When the hole forming the boundary between the regions r is a semi-through hole, it is formed on the display surface side of the light guide plate 52 on the liquid crystal panel 51 side or on the non-display surface side opposite to the side on which the liquid crystal panel 51 is disposed. However, when the semi-through hole is formed on the display surface side of the light guide plate 52 on the liquid crystal panel 51 side, the optical sheet 54 is disposed away from the light guide plate 52 and emitted from the light guide plate 52 to the display surface side. Increasing the discreteness of the light produced.

  In the first to fifth embodiments described above, the liquid crystal television has been described as an example of the liquid crystal display device. However, various electronic devices such as a personal computer display, a commercial large display device, and a PDA (Personal Digital Assistants). If the liquid crystal display device is used, the present invention can be applied widely and effectively.

(a) is a front view of the liquid crystal television of 1st Embodiment of this invention, (b) is the sectional view on the AA line of (a). (a) is the perspective view seen from diagonally upward which shows the state which decomposed | disassembled the principal part of the structure which displays an image | video on the display screen shown in FIG.1 (b), (b) is a perspective view of FIG.1 (a). It is a BB line sectional enlarged view. (a) is a front view which shows the light-guide plate, light source module, etc. of 1st Embodiment, (b) is the CC sectional view taken on the line of (a). It is CC sectional view enlarged view of CC guides, such as a light-guide plate shown to Fig.3 (a) of 2nd Embodiment. It is CC sectional view enlarged view of CC guides, such as a light-guide plate shown to Fig.3 (a) of 3rd Embodiment. It is CC sectional view enlarged view of CC etc., such as a light-guide plate shown to Fig.3 (a) of the modification of 3rd Embodiment. It is CC sectional view enlarged view of CC etc., such as a light-guide plate shown to Fig.3 (a) of 4th Embodiment. It is CC sectional view enlarged view of CC etc. of the light-guide plate shown to Fig.3 (a) of the modification of 4th Embodiment. (a) is a front view which shows the light-guide plate, light source module, etc. of 5th Embodiment, (b) is the DD sectional view taken on the line of (a), (c) is (a) FIG. It is the F section enlarged view of 5th Embodiment of Fig.9 (a). (a) is a front view of a conventional liquid crystal television, and (b) and (c) are respectively arranged on both outer sides of the light guide plate and the display screen arranged on the back side of the display screen in the conventional liquid crystal television. It is a conceptual front view showing an example of the configuration of the light source. (a) is the front view which showed the light-guide plate and light source which formed the groove part which divides | segments the conventional integrated light-guide plate into each area | region, (b), (c) is H of (a), respectively. FIG. 4 is an enlarged cross-sectional view taken along the line -H, illustrating how light travels around a groove in the light guide plate.

Explanation of symbols

1. Liquid crystal panel (Liquid crystal panel of claim 9)
2 Light guide plate (Light guide plate of claim 9)
10 LCD TV (Liquid Crystal Display)
22 Light Guide Plate (Light Guide Plate of Claims 1 and 2)
23 reflective member (reflective member of claim 1)
31 Light Guide Plate (Liquid Crystal Panel of Claim 3)
32 Light guide plate (Light guide plate according to claims 3, 5 and 6)
32 'light guide plate (light guide plate according to claims 4, 5 and 6)
36. Insertion light guide member (fitting member of claim 3)
36 'insertion light guide member (fitting member of claim 4)
42 Light Guide Plate (Light Guide Plate of Claim 7)
42 'light guide plate (light guide plate of claim 8)
46 Non-transparent highly reflective insertion light guide member (fitting member of claim 7)
46 'non-transparent high reflection insertion light guide member (fitting member of claim 8)
52 Light Guide Plate (Light Guide Plate of Claims 11 and 12)
2m groove (groove of claims 1 and 2)
3J 'resin (transparent resin of claim 4)
3m groove part (groove part of claims 3, 5 and 6)
3m 'groove (grooves according to claims 4, 5 and 6)
4J 'resin (transparent resin of claim 8)
4m groove (groove of claim 7)
4m 'groove (groove of claim 8)
G Display screen (all display areas)
h Through-hole (through-hole of claims 11 and 12)
m Groove (groove of claims 9 and 10)
m1 groove side surface (groove side surface of claims 9 and 10)
m2 groove side surface (groove side surface of claims 9 and 10)
m3 groove bottom surface (groove bottom surface of claims 9 and 10)
K (K11, ..., K17, K21, ..., K27)
Light source module (light source)
r (r1, r2,..., r7) region (divided region)
s51 Width dimension s52 Length dimension

Claims (12)

A liquid crystal display device comprising: a light source and a lighting device having a light guide plate that diffuses light of the light source to be a surface light source; and a liquid crystal panel that is disposed opposite to the lighting device and has a liquid crystal layer,
The light guide plate has a groove on the side opposite to the side on which the liquid crystal panel is arranged to divide the entire display region into divided regions,
And it is arrange | positioned along the surface containing the said groove part in the said light-guide plate, The reflection member which reflects the light radiate | emitted from the said light-guide plate is provided. The liquid crystal display device characterized by the above-mentioned. A liquid crystal display device comprising: a light source and a lighting device having a light guide plate that diffuses light of the light source to be a surface light source; and a liquid crystal panel that is disposed opposite to the lighting device and has a liquid crystal layer,
The light guide plate has a groove on the side opposite to the side on which the liquid crystal panel is arranged to divide the entire display region into divided regions,
A liquid crystal display device comprising: a frame member having a reflective surface that is disposed along a surface of the light guide plate including the groove and reflects light emitted from the light guide plate. A liquid crystal display device comprising: a light source and a lighting device having a light guide plate that diffuses light of the light source to be a surface light source; and a liquid crystal panel that is disposed opposite to the lighting device and has a liquid crystal layer,
The light guide plate has a groove that divides the entire display region into divided regions,
The liquid crystal display device further comprises a transparent fitting member having a smaller dimension than the groove portion of the light guide plate and having the same or substantially the same refractive index as the light guide plate fitted in the groove portion. The fitting member is fixed to the groove using at least a part of a surface facing the groove of the light guide plate using a transparent resin having the same or substantially the same refractive index as the light guide plate. The liquid crystal display device according to claim 3. The liquid crystal display device according to claim 3, wherein a cross section of the groove portion in the short side direction of the light guide plate has a rectangular shape. The liquid crystal display device according to claim 3, wherein the groove portion of the light guide plate is provided on a side of the light guide plate opposite to a side where the liquid crystal panel is disposed. . A liquid crystal display device comprising: a light source and a lighting device having a light guide plate that diffuses light of the light source to be a surface light source; and a liquid crystal panel that is disposed opposite to the lighting device and has a liquid crystal layer,
The light guide plate has a groove on the side opposite to the side on which the liquid crystal panel is arranged to divide the entire display region into divided regions,
And a fitting member having a size smaller than that of the groove portion of the light guide plate and fitted in the groove portion, and a surface facing the groove portion formed on a reflection surface that reflects light emitted from the light guide plate. A liquid crystal display device. The liquid crystal display device according to claim 7, wherein the fitting member is fixed to a groove portion of the light guide plate using a transparent resin. A liquid crystal display device comprising: a light source and a lighting device having a light guide plate that diffuses light of the light source to be a surface light source; and a liquid crystal panel that is disposed opposite to the lighting device and has a liquid crystal layer,
The light guide plate has a groove with a rectangular cross section in the short side direction that divides the entire area of the display screen into divided areas,
The radius of curvature of the corner portion formed by the groove side surface and the groove bottom surface of the groove portion is greater than 0 and 50 μm or less, and the groove side surface forming the groove portion and the arithmetic mean roughness of the groove surface including the groove bottom surface are , Greater than 0 and less than or equal to 15 nm. The width of the groove is greater than 0 and 0.5 mm or less, and
10. The liquid crystal display device according to claim 9, wherein angles formed by both groove side surfaces and the groove bottom surface of the groove portion are each within 90 degrees ± 1 degree. A liquid crystal display device comprising: a light source and a lighting device having a light guide plate that diffuses light of the light source to be a surface light source; and a liquid crystal panel that is disposed opposite to the lighting device and has a liquid crystal layer,
The liquid crystal display device, wherein the light guide plate is provided with a plurality of through-holes or half-through-holes that form a boundary between the divided regions that divides the entire display region into a plurality of divided regions. The through holes or the half through holes in the light guide plate each have a width dimension of greater than 0 and 0.5 mm or less, and a length dimension of greater than 0 and 10 mm or less, and the pitch dimension between the through holes or between the half through holes. The liquid crystal display device according to claim 11, wherein is greater than 0 and equal to or less than 20 mm.

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