JP5869917B2 - Liquid crystal display - Google Patents

Description

  Embodiments described herein relate generally to a liquid crystal display device.

  Liquid crystal display devices are utilized in various fields as display devices for OA equipment such as personal computers and televisions, taking advantage of features such as light weight, thinness, and low power consumption. In recent years, liquid crystal display devices are also used as display devices for mobile terminal devices such as mobile phones, car navigation devices, and amusement devices.

  Among such liquid crystal display devices, in a configuration in which an illumination unit (that is, a backlight) is provided on the back side of the liquid crystal display panel, a brighter and higher display quality is required. In recent years, a lighting unit having directivity capable of irradiating light in at least two directions has been proposed as a lighting unit mounted on such a liquid crystal display device. A stereoscopic display device that displays a stereoscopic image without using glasses by combining a lighting unit having such directivity and a liquid crystal panel, a display device that can observe different images for each observation direction, and the like have been developed. .

JP 2001-66547 A

  An object of this embodiment is to provide a liquid crystal display device capable of horizontal 3D display and vertical 3D display.

According to this embodiment,
A liquid crystal display panel having a first long side and a second long side parallel to each other and a first short side and a second short side parallel to each other; and a liquid crystal display panel side disposed on the back side of the liquid crystal display panel A first light-guiding plate having a first light-exiting surface facing the first light-incident surface, a first light-incident surface aligned with the first long side, and a second light-incident surface aligned with the first short side, and a first light-opposing plate facing the first light-incident surface. A light source and a second light source facing the second incident surface, and radiates light from the first light source or the second light source in a first direction from the first light emitting surface to A first illumination unit that illuminates; a second emission surface that is disposed between the liquid crystal display panel and the first illumination unit and faces the liquid crystal display panel; a third incidence surface aligned with the second long side; and A second light guide plate having a fourth incident surface aligned with the second short side, and opposed to the third incident surface A third light source and a fourth light source facing the fourth incident surface, and the second light source emits light from the third light source or the fourth light source different from the second direction from the first direction. And a second illumination unit that emits light in the direction and illuminates the liquid crystal display panel.

FIG. 1 is an exploded perspective view schematically showing a configuration example of a liquid crystal display device according to the present embodiment. FIG. 2 is a diagram illustrating a shape example of a reflection pattern applicable to the first light guide plate and the second light guide plate illustrated in FIG. 1. FIG. 3 shows a cross-sectional shape of the first light guide plate having a plurality of first reflection patterns cut along the line AA along the first direction and when cut along the line BB along the second direction. It is a figure which shows a cross-sectional shape. FIG. 4 is a diagram illustrating another shape example of the reflection pattern applicable to the first light guide plate and the second light guide plate illustrated in FIG. 1. FIG. 5 is a diagram for explaining an example of a light guide plate applicable to the liquid crystal display device of the present embodiment. FIG. 6 is a diagram for explaining an example of a reflection pattern applicable to the liquid crystal display device of the present embodiment. FIG. 7 is a diagram schematically showing an example of a reflection pattern applicable to the liquid crystal display device of the present embodiment. FIG. 8 is a schematic diagram for explaining a shape example of a prism sheet applicable to the present embodiment. FIG. 9 is a schematic diagram for explaining a light source that is turned on during horizontal display and vertical display. FIG. 10 is a schematic diagram for explaining the traveling direction of light in the first illumination unit during horizontal 3D display. FIG. 11 is a schematic diagram for explaining the traveling direction of light in the second illumination unit during horizontal 3D display. FIG. 12 is a schematic diagram for explaining light traveling directions in the first illumination unit and the second illumination unit in the vertical 3D display. FIG. 13 is a diagram for explaining the improvement of the light utilization efficiency by the light guide plate applicable to this embodiment.

  Hereinafter, the present embodiment will be described in detail with reference to the drawings. In each figure, the same reference numerals are given to components that exhibit the same or similar functions, and duplicate descriptions are omitted.

  FIG. 1 is an exploded perspective view schematically showing a configuration example of a liquid crystal display device according to the present embodiment.

  That is, the liquid crystal display device 1 includes a transmissive liquid crystal display panel LPN having a substantially rectangular flat plate shape, a first illumination unit 10 and a second illumination unit 20 that illuminate the liquid crystal display panel LPN, and a prism sheet 30. Yes.

  The liquid crystal display panel LPN includes a substantially rectangular flat array substrate AR and a counter substrate CT, and a liquid crystal layer LQ sealed between the array substrate AR and the counter substrate CT. In the illustrated example, the liquid crystal display panel LPN has a first long side L1 and a second long side L2 that are parallel to each other, and a first short side S1 and a second short side S2 that are parallel to each other. The first long side L1 and the second long side L2 each extend along the first direction X. The first short side S1 and the second short side S2 extend along the second direction Y, respectively. The second direction Y is orthogonal to the first direction X.

  The liquid crystal display panel LPN includes a substantially rectangular active area (display area) ACT for displaying an image. The active area ACT is composed of a plurality of pixels PX arranged in a matrix. In the active area ACT, a plurality of gate lines GL extending along the first direction X, a plurality of source lines SL extending along the second direction Y, the gate lines GL and the source lines arranged in each pixel PX A switching element SW electrically connected to the SL, a pixel electrode PE connected to the switching element SW of each pixel PX, a common electrode CE arranged in common to the plurality of pixel electrodes PE, and the like are provided. The pixel electrode PE and the common electrode CE are formed of a light-transmitting conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO). The common electrode CE for applying a voltage to the liquid crystal layer LQ due to a potential difference with the pixel electrode PE may be provided on the array substrate AR together with the pixel electrode PE, or may be provided on the counter substrate CT separately from the pixel electrode PE. May be.

  In the liquid crystal display panel LPN, an optical element including a polarizing plate is provided on the outer surface of the array substrate AR, and similarly, an optical element including a polarizing plate is also provided on the outer surface of the counter substrate CT. Omitted.

  The first lighting unit 10 is disposed on the back side of the liquid crystal display panel LPN, that is, on the array substrate AR side. The second lighting unit 20 is disposed between the liquid crystal display panel LPN and the first lighting unit 10. The prism sheet 30 is disposed between the liquid crystal display panel LPN and the second illumination unit 20. That is, the first lighting unit 10, the second lighting unit 20, the prism sheet 30, and the liquid crystal display panel LPN are stacked in this order along the third direction Z orthogonal to the first direction X and the second direction Y. Yes.

  The first lighting unit 10 includes a first light guide plate LG1, a first light source LS1, and a second light source LS2.

  The first light guide plate LG1 is formed in a rectangular flat plate shape, and has a first emission surface OUT1, a first incident surface IN1, and a second incident surface IN2. The first emission surface OUT1 is a plane that faces the liquid crystal display panel LPN side. The first emission surface OUT1 is, for example, a rectangular surface parallel to the XY plane, and has a long side in the first direction X and a short side in the second direction Y. The first incident surface IN1 is a plane aligned with the first long side L1. The first incident surface IN1 is, for example, a rectangular surface that is formed parallel to the first long side L1 and parallel to the XZ plane, has a long side in the first direction X, and is short in the third direction Z. Has an edge. The second incident surface IN2 is a plane aligned with the first short side S1. The second incident surface IN2 is, for example, a rectangular surface that is formed in parallel with the first short side S1 and parallel to the YZ plane, has a long side in the second direction Y, and is short in the third direction Z. Has an edge.

  The first light source LS1 is opposed to the first incident surface IN1. The first light source LS1 may be a plurality of light emitting diodes (LEDs) arranged along the first direction X, or a cold cathode tube (CCFL) extended along the first direction X. good. Such a first light source LS1 emits light in a second direction Y parallel to the normal line of the first incident surface IN1.

  The second light source LS2 faces the second incident surface IN2. The second light source LS2 may be a plurality of light emitting diodes (LEDs) arranged along the second direction Y, or may be a cold cathode tube (CCFL) extending along the second direction Y. good. Such a second light source LS2 emits light in a first direction X parallel to the normal line of the second incident surface IN2.

  Such a first illumination unit 10 emits light emitted from the first light source LS1 or the second light source LS2 from the first emission surface OUT1 in the first emission direction to emit light and illuminates the liquid crystal display panel LPN. Functions as a light source.

  That is, the first light guide plate LG1 is emitted from the first emission surface OUT1 while reflecting incident light emitted from the first light source LS1 and incident from the first incident surface IN1 in a direction toward the second incident surface IN2, and A first reflection pattern R1 that is emitted from the first emission surface OUT1 while reflecting incident light emitted from the second light source LS2 and incident from the second incidence surface IN2 in a direction toward the first incidence surface IN1 is provided.

  The first reflection pattern R1 is formed on the surface of the first light guide plate LG1 opposite to the first light exit surface OUT1. The first reflection pattern R1 is a triangular pyramid-shaped recess whose bottom surface B1 is a substantially right triangle. Although the detailed shape of the first reflection pattern R1 will be described later, the first reflection pattern R1 includes a first reflection surface RS1 facing the first incident surface IN1 and the second incident surface IN2. The plurality of first reflection patterns R1 are formed to be aligned in the first direction X and the second direction Y, and the first reflection surfaces RS1 of all the first reflection patterns R1 face the same direction.

  The emitted light from the first light source LS1 is incident from the first incident surface IN1 and travels along the second direction Y. Such incident light is reflected by the first reflecting surface RS1 of the first reflecting pattern R1, and the optical path is bent by 90 ° in the XY plane. That is, the reflected light on the first reflecting surface RS1 travels along the first direction X toward the second incident surface IN2. Moreover, the reflected light is reflected obliquely upward toward the first emission surface OUT1 and is emitted from the first emission surface OUT1. Thus, the emitted light from the first light source LS1 is emitted at a first emission angle (for example, about 70 °) θ1 with respect to the normal line of the first emission surface OUT1.

  The emitted light from the second light source LS2 is incident from the second incident surface IN2 and travels along the first direction X. Such incident light is reflected by the first reflecting surface RS1, and the optical path is bent by 90 ° in the XY plane. That is, the reflected light on the first reflecting surface RS1 travels along the second direction Y toward the first incident surface IN1. Moreover, the reflected light is reflected obliquely upward toward the first emission surface OUT1 and is emitted from the first emission surface OUT1. Thereby, the emitted light from the second light source LS2 is emitted at a second emission angle (for example, about 70 °) θ2 with respect to the normal line of the first emission surface OUT1. The first emission angle θ1 and the second emission angle θ2 are substantially equal angles.

  On the other hand, the second illumination unit 20 includes a second light guide plate LG2, a third light source LS3, and a fourth light source LS4.

  The second light guide plate LG2 is located above the first light guide plate LG1. The second light guide plate LG2 is formed in a rectangular flat plate shape, and has a second emission surface OUT2, a third incident surface IN3, and a fourth incident surface IN4. The second emission surface OUT2 is a plane that faces the liquid crystal display panel LPN side. The second emission surface OUT2 is, for example, a rectangular surface parallel to the XY plane, and has a long side in the first direction X and a short side in the second direction Y. The third incident surface IN3 is a plane aligned with the second long side L2. The third incident surface IN3 is, for example, a rectangular surface that is formed parallel to the second long side L2 and parallel to the XZ plane, has a long side in the first direction X, and is short in the third direction Z. Has an edge. That is, the third incident surface IN3 is located on the side opposite to the first incident surface IN1, and is a plane parallel to the first incident surface IN1. The fourth incident surface IN4 is a plane aligned with the second short side S2. The fourth incident surface IN4 is, for example, a rectangular surface that is formed parallel to the second short side S2 and parallel to the YZ plane, has a long side in the second direction Y, and is short in the third direction Z. Has an edge. That is, the fourth incident surface IN4 is located on the side opposite to the second incident surface IN2, and is a plane parallel to the second incident surface IN2.

  The third light source LS3 is opposed to the third incident surface IN3. The third light source LS3 may be a plurality of light emitting diodes (LEDs) arranged along the first direction X, or may be a cold cathode tube (CCFL) extended along the first direction X. good. The third light source LS3 emits light in the second direction Y parallel to the normal line of the third incident surface IN3.

  The fourth light source LS4 faces the fourth incident surface IN4. The fourth light source LS4 may be a plurality of light emitting diodes (LEDs) arranged along the second direction Y, or may be a cold cathode tube (CCFL) extended along the second direction Y. good. Such a fourth light source LS4 emits light in a first direction X parallel to the normal line of the fourth incident surface IN4.

  Such a second illumination unit 20 emits radiation from the third light source LS3 or the fourth light source LS4 from the second emission surface OUT2 in a second emission direction different from the first emission direction, and emits surface light. It functions as a surface light source that illuminates the display panel LPN.

  That is, the second light guide plate LG2 emits the incident light emitted from the third light source LS3 and incident from the third incident surface IN3 in the direction toward the fourth incident surface IN4, and is emitted from the second emission surface OUT2, and A second reflection pattern R2 that is emitted from the second emission surface OUT2 while reflecting incident light emitted from the fourth light source LS4 and incident from the fourth incidence surface IN4 in a direction toward the third incidence surface IN3 is provided.

  The second reflection pattern R2 is formed on the surface opposite to the second emission surface OUT2 of the second light guide plate LG2. This second reflection pattern R2 is a triangular pyramid-shaped recess whose bottom surface B2 is a substantially right triangle. The detailed shape of the second reflection pattern R2 will be described later, but has a second reflection surface RS2 facing the third incident surface IN3 and the fourth incident surface IN4. The plurality of second reflection patterns R2 are formed so as to be aligned in the first direction X and the second direction Y, and the second reflection surfaces RS2 of all the second reflection patterns R2 face the same direction.

  The emitted light from the third light source LS3 is incident from the third incident surface IN3 and travels along the second direction Y. Such incident light is reflected by the second reflecting surface RS2 of the second reflecting pattern R2, and the optical path is bent 90 ° in the XY plane. That is, the reflected light on the second reflecting surface RS2 travels along the first direction X toward the fourth incident surface IN4. Moreover, the reflected light is reflected obliquely upward toward the second emission surface OUT2, and is emitted from the second emission surface OUT2. Thereby, the emitted light from the third light source LS3 is emitted at a third emission angle (for example, about 70 °) θ3 with respect to the normal line of the second emission surface OUT2.

  However, the direction in which the emitted light from the third light source LS3 travels is entirely opposite to the direction in which the emitted light from the first light source LS1 travels in the XY plane. That is, the emitted light from the first light source LS1 is emitted from the first emission surface OUT1 in the positive (+) direction in the first direction X, while the emitted light from the third light source LS3 is emitted from the second emission surface OUT2. The light is emitted in the negative (−) direction in the first direction X.

  The emitted light from the fourth light source LS4 is incident from the fourth incident surface IN4 and travels along the first direction X. Such incident light is reflected by the second reflecting surface RS2, and the optical path is bent 90 ° in the XY plane. That is, the reflected light on the second reflecting surface RS2 travels along the second direction Y toward the third incident surface IN3. Moreover, the reflected light is reflected obliquely upward toward the second emission surface OUT2, and is emitted from the second emission surface OUT2. Thereby, the emitted light from the fourth light source LS4 is emitted at a fourth emission angle (for example, about 70 °) θ4 with respect to the normal line of the second emission surface OUT2. The third emission angle θ3 and the fourth emission angle θ4 are substantially equal angles.

  However, the direction in which the emitted light from the fourth light source LS4 travels is entirely opposite to the direction in which the emitted light from the second light source LS2 travels in the XY plane. That is, the emitted light from the second light source LS2 is emitted from the first emission surface OUT1 in the negative (−) direction in the second direction Y, while the emitted light from the fourth light source LS4 is emitted from the second emission surface OUT2. The light is emitted in the positive (+) direction in the second direction Y.

  Although details of the prism sheet 30 will be described later, a long side 30L1 parallel to the first long side L1, a long side 30L2 parallel to the second long side L2, a short side 30S1 parallel to the first short side S1, and a first side 2 A rectangular plate having a short side 30S2 parallel to the short side S2. Such a prism sheet 30 includes a plurality of quadrangular pyramid prisms 31 arranged on the side facing the second illumination unit 20. The plurality of prisms 31 are formed so as to be aligned in the first direction X and the second direction Y.

  Although not shown, between the first light guide plate LG1 and the second light guide plate LG2, between the second light guide plate LG2 and the prism sheet 30, and between the prism sheet 30 and the liquid crystal display panel LPN, Various optical films may be arranged respectively.

  FIG. 2 is a diagram illustrating a shape example of a reflection pattern applicable to the first light guide plate LG1 and the second light guide plate LG2 illustrated in FIG.

  The first reflection pattern R1 and the second reflection pattern R2 are triangular pyramids having substantially the same shape. Here, the shape of the first reflection pattern R1 is illustrated and described, and the description of the second reflection pattern R2 is omitted. To do.

  The bottom surface B1 of the first reflective pattern R1 has a first side B11 parallel to the first direction X, a second side B12 parallel to the second direction Y, and a hypotenuse B13. The first side B11 and the second side It is a right triangle that the side B12 intersects at a right angle. In the illustrated example, the length of the first side B11 is equal to the length of the second side B12. That is, the bottom surface B1 is a right-angled isosceles triangle. In the first reflection pattern R1, the hypotenuse B13 is located on the first incident surface IN1 side and the second incident surface IN2 side with respect to the right angle. In the second reflection pattern R2 (not shown), the hypotenuse of the base B2 is located on the third incident surface IN3 side and the fourth incident surface IN4 side with respect to the right angle.

  The first side surface BS1 rising in the third direction Z from the first side B11 and the second side surface BS2 rising in the third direction Z from the second side B12 have substantially the same shape. The first reflecting surface RS1 extends in an oblique direction with respect to the third direction Z from the oblique side B13, and intersects the first side surface BS1 and the second side surface BS2. Such a first reflecting surface RS1 faces the first incident surface IN1 side and the second incident surface IN2 side. In the second reflection pattern R2 (not shown), the second reflection surface RS2 faces the third incident surface IN3 side and the fourth incident surface IN4 side.

  The first light guide plate LG1 is formed, for example, by patterning a first reflection pattern R1 that becomes a concave portion on the lower surface of a plate-like transparent sheet member using a mold or the like. The second light guide plate LG2 having the second reflection pattern R2 is similarly formed.

  FIG. 3 is a cross-sectional shape of the first light guide plate LG1 having a plurality of first reflection patterns R1 cut along an AA line along the first direction X and a BB line along the second direction Y. It is a figure which shows the cross-sectional shape when cut | disconnecting.

  The cross-sectional shape along the first direction X shown in FIG. 3A is formed in a sawtooth shape by the second side surface BS2 and the first reflecting surface RS1. An air layer is present in the recess between the second side surface BS2 and the first reflecting surface RS1. The cross-sectional shape along the second direction Y shown in (B) of FIG. 3 is formed in a sawtooth shape by the first side surface BS1 and the first reflecting surface RS1. An air layer is present in the recess between the first side surface BS1 and the first reflecting surface RS1.

  FIG. 4 is a diagram illustrating another shape example of the reflection pattern applicable to the first light guide plate LG1 and the second light guide plate LG2 illustrated in FIG.

  The first reflection pattern R1 and the second reflection pattern R2 can be pyramids having substantially the same shape. Here, the shape of the first reflection pattern R1 is illustrated and described, and the second reflection pattern R2 is illustrated. The description about is omitted.

  The shape example shown here is different from the shape example shown in FIG. 2 in that the number of sides of the bottom surface B1 of the first reflection pattern R1 is four polygons. That is, the bottom surface B1 includes a first side B11 parallel to the first direction X, a second side B12 parallel to the second direction Y, a first oblique side B13 connected to the first side B11, and a second side B12. It has the 2nd hypotenuse B14 connected. The first side B11 and the second side B12 intersect at right angles, and the length of the first side B11 is equal to the length of the second side B12. The length of the first hypotenuse B13 is also equal to the length of the second hypotenuse B14.

  The first side surface BS1 rising in the third direction Z from the first side B11 and the second side surface BS2 rising in the third direction Z from the second side B12 have substantially the same shape. The first reflecting surface RS1 includes a first slope RS11 and a second slope RS12. The first slope RS11 extends in an oblique direction with respect to the third direction Z from the first hypotenuse B13, and intersects the first side surface BS1. Such first slope RS11 faces the second incident surface IN2. The second slope RS12 extends obliquely from the second hypotenuse B14 with respect to the third direction Z, and intersects the second side face BS2 and the first slope RS11. Such second inclined surface RS12 faces the first incident surface IN1 side.

  The reflection pattern is not limited to the shape example described above. For example, the bottom surface is a polygon having four or more sides, the angle formed by the two sides of the longest side and the second longest side is 90 ° or more, and the two sides are substantially equal in length. It is good also as a structure of. Alternatively, the weight-shaped bottom surface may have a shape in which a portion corresponding to the hypotenuse is curved.

  About the 1st reflective pattern R1 and 2nd reflective pattern R2 of such a shape, by optimizing the angle which the bottom face and a reflective surface make, and the diagonal angle with the right angle of a bottom face, reflected light is reflected. It can be taken out at a desired angle.

  For example, in the first light guide plate LG1, the shape of the first reflection pattern R1 is the direction in which the emitted light from the first light source LS1 or the emitted light from the second light source LS2 travels and the reflection reflected by the first reflecting surface RS1. The angle α formed by the direction in which the light travels is projected onto the XY plane is designed to be approximately 90 °. The shape of the first reflection pattern R1 is such that the angle β formed between the traveling direction of the reflected light reflected by the first reflection surface RS1 and the normal line of the first light guide plate LG1 is the critical angle of the material of the first light guide plate LG1. Designed to be smaller than Thereby, it is possible to take out the light which propagated the inside of 1st light-guide plate LG1 outside.

  In the second light guide plate LG2, the shape of the second reflection pattern R2 is the traveling direction of the emitted light from the third light source LS3 or the emitted light from the fourth light source LS4 and the reflected light reflected by the second reflecting surface RS2. It is designed such that an angle α formed between the traveling direction and the direction projected onto the XY plane is approximately 90 °. The shape of the second reflection pattern R2 is such that the angle β formed between the traveling direction of the reflected light reflected by the second inclined surface RS2 and the normal line of the second light guide plate LG2 is the critical angle of the material of the second light guide plate LG2. Designed to be smaller than Thereby, it is possible to take out the light which propagated the inside of 2nd light-guide plate LG2 outside.

  Hereinafter, an example of the first light guide plate LG1 will be described.

  When the first light guide plate LG1 is made of acrylic (refractive index is 1.49) and the periphery of the first light guide plate LG1 is an air layer, as shown in FIG. 5, the first emission angle θ1 and the second emission angle In order to set θ2 to 70 °, the formed angle β is set to 39.1 °. As shown in FIG. 6, in the XY plane, when the formed angle α is 90 °, when the formed angle β is 39.1 °, the first side on the bottom surface B1 of the first reflection pattern R1 The angle γ formed by B11 and the hypotenuse B13 is preferably 57.7 °, and the angle δ formed by the bottom surface B1 and the first inclined surface RS1 is preferably 56.8 °.

  In the case of the reflection pattern of the shape example shown in FIG. 4, as shown in FIG. 7A, the angle γ formed by the first side B11 and the first hypotenuse B13 and the second side B12 and the second hypotenuse B14 The angle γ formed is 57.7 °, and as shown in FIGS. 7B and 7C, the angle δ formed between the bottom surface B1 and the first slope RS11 and the bottom surface B1 and the second slope RS12. The formed angles δ are all 56.8 °.

  Next, a configuration example of the prism sheet 30 illustrated in FIG. 1 will be described.

  FIG. 8 is a schematic diagram for explaining a shape example of the prism sheet 30 applicable to this embodiment.

  (A) in the figure is an XY plan view of the surface of the prism sheet 30 on which the prism 31 is formed. (B) in the figure is a cross-sectional view when the prism sheet 30 shown in (A) is cut along line EE, and (C) in the figure shows the prism sheet 30 shown in (A) as F- It is sectional drawing when cut | disconnecting by F line, (D) in a figure is sectional drawing when the prism sheet 30 shown to (A) is cut | disconnected by GG line.

  In the prism sheet 30, the shape of the prism 31 is a quadrangular pyramid whose bottom surface 31B is a square. The bottom surface 31B is defined by four sides: a pair of sides parallel to the first direction X and a pair of sides parallel to the second direction Y. The four sides of the bottom surface 31B are parallel to the four sides of the prism sheet 30, that is, the long sides 30L1 and 30L2, and the short sides 30S1 and 30S2.

  The apex 31T of the prism 31 is on the side facing the second illumination unit 20 (not shown). The prism 31 located at the center of the prism sheet 30 has a shape in which the foot of the perpendicular line dropped from the apex 31T to the square bottom surface 31B of the prism sheet surface coincides with the center of gravity of the bottom surface 31B. Furthermore, as the arrangement position of the prism 31 becomes farther from the center of the prism sheet 30, the position of the perpendicular foot dropped from the apex 31T is greatly shifted toward the outside of the prism sheet 30 from the center of gravity of the bottom surface 31B. In other words, as the distance from the center of the prism sheet 30 to the position where the prism 31 is arranged increases, the amount of deviation between the position of the foot of the perpendicular dropped from the vertex 31T and the center of the bottom surface 31B increases. ing. Moreover, the legs of the perpendicular line dropped from the apex 31T of the prism 31 are located on a straight line connecting the center of gravity of the bottom surface 31B and the center of the prism sheet 30.

  When light emitted from the first illumination unit 10 and the second illumination unit 20 enters such a prism sheet 30, it is reflected by the prism 31 and illuminates the liquid crystal display panel LPN. At this time, for example, the prism 31 reflects the emitted light emitted from the positive direction to the negative direction in the first direction X from the negative direction to the positive direction in the first direction X, or from the negative direction to the positive direction in the first direction X. The outgoing light emitted in the first direction X is reflected from the positive direction to the negative direction, and the outgoing light emitted in the second direction Y from the positive direction to the negative direction is reflected from the negative direction in the second direction Y to the positive direction. The reflected light is reflected or the emitted light emitted in the second direction Y from the negative to the positive direction is reflected in the second direction Y from the positive to the negative direction.

  Next, an example of the operation of 2D display and naked-eye 3D display by the liquid crystal display device of this embodiment will be described.

  FIG. 9 is a schematic diagram for explaining a light source that is turned on during horizontal display and vertical display. In the illustrated example, when the vertical display is performed, the entire liquid crystal display device 1 is rotated 90 degrees counterclockwise as compared with the case of performing the horizontal display.

  (A) in the drawing shows a state in which the longitudinal direction of the liquid crystal display panel LPN, that is, the first direction X is directed in the horizontal direction. That is, the first short side S1 and the second short side S2 of the liquid crystal display panel LPN are located on the right side and the left side of the observation position, respectively. In this state, horizontal 2D display or horizontal 3D display is possible. When realizing such a horizontal display, among the four light sources located on the four sides of the liquid crystal display panel LPN, the light sources along the long side of the liquid crystal display panel LPN, that is, the first light source LS1 and the third light source LS3 are turned on. (ON).

  When performing horizontal 3D display, the first light source LS1 and the third light source LS3 are alternately lit in synchronization with an image displayed on the liquid crystal display panel LPN. That is, the first light source LS1 is turned on in synchronization with the liquid crystal display panel LPN displaying a first image (for example, an image for the left eye) toward one eye of the observer, and at this timing, the third light source LS3 is turned on. Off. On the other hand, the third light source LS3 is turned on in synchronization with the liquid crystal display panel LPN displaying a second image (for example, an image for the right eye) toward the other eye of the observer. At this timing, the first light source LS1 is turned on. Off. Note that the second light source LS2 and the fourth light source LS4 are always turned off (OFF) during horizontal 3D display.

  When performing horizontal 2D display, the first light source LS1 and the third light source LS3 are turned on almost simultaneously, and the second light source LS2 and the fourth light source LS4 are turned off. Note that, when performing horizontal 2D display, the second light source LS2 and the fourth light source LS4 may be lit supplementarily. As a result, it is possible to improve the luminance of the horizontal 2D display and to expect the effect that the viewing angle at which high luminance can be obtained can be expanded.

  (B) in the figure shows a state in which the longitudinal direction of the liquid crystal display panel LPN, that is, the first direction X faces the vertical direction (or the second direction Y faces the horizontal direction). That is, the first long side L1 and the second long side L2 of the liquid crystal display panel LPN are located on the right side and the left side of the observation position, respectively. In this state, vertical 2D display or vertical 3D display is possible. When realizing such vertical display, among the four light sources located on the four sides of the liquid crystal display panel LPN, the light sources along the short side of the liquid crystal display panel LPN, that is, the second light source LS2 and the fourth light source LS4 are turned on. (ON).

  When performing vertical 3D display, the second light source LS2 and the fourth light source LS4 are alternately turned on in synchronization with an image displayed on the liquid crystal display panel LPN. That is, the second light source LS2 is lit in synchronization with the liquid crystal display panel LPN displaying a first image (for example, an image for the left eye) toward one eye of the observer. At this timing, the fourth light source LS4 is turned on. Off. On the other hand, the fourth light source LS4 is turned on in synchronization with the liquid crystal display panel LPN displaying the second image (for example, the right eye image) toward the other eye of the observer, and at this timing, the second light source LS2 is turned on. Off. Note that, during vertical 3D display, the first light source LS1 and the third light source LS3 are always turned off (OFF).

  When performing vertical 2D display, the second light source LS2 and the fourth light source LS4 are turned on almost simultaneously, and the first light source LS1 and the third light source LS3 are turned off. Note that, when performing vertical 2D display, the first light source LS1 and the third light source LS3 may be lit supplementarily. Thereby, it is possible to improve the luminance of the vertical 2D display, and it is also possible to expect an effect that the viewing angle at which high luminance can be obtained can be expanded.

  FIG. 10 is a schematic diagram for explaining the traveling direction of light in the first illumination unit 10 in horizontal 3D display. In particular, here, the traveling direction of the emitted light from the first illumination unit 10 synchronized with the left-eye image in the horizontal 3D display is shown.

  The example shown in FIG. 5A corresponds to the case where the liquid crystal display panel LPN displays the first image at the first timing for performing horizontal 3D display. When performing horizontal 3D display, the positive (+) direction in the first direction X corresponds to the right side of the observation position, and the negative (−) direction in the first direction X corresponds to the left side of the observation position.

  In the horizontal 3D display, the first lighting unit 10 lights the first light source LS1 in synchronization with the liquid crystal display panel LPN displaying the first image. The emitted light from the first light source LS1 enters the first light guide plate LG1 from the first incident surface IN1, and travels along the second direction Y. The incident light is reflected by the first reflection pattern R1, travels in the positive direction of the first direction X, and is emitted from the first emission surface OUT1. That is, the direction of the emitted light emitted from the first emission surface OUT1 is a positive direction in the first direction X corresponding to the right side of the observation position.

  As indicated by (B) in the figure, the emitted light emitted from the first emission surface OUT1 toward the right side in the figure (that is, in the positive direction of the first direction X) is transmitted through the second illumination unit 20. Then, the light is reflected by the prism sheet 30 toward the left side in the drawing (that is, in the negative direction of the first direction X). This reflected light reaches the liquid crystal display panel LPN displaying the left-eye image as the first image, and is selectively transmitted by the liquid crystal display panel LPN. The light transmitted through the liquid crystal display panel LPN enters the left eye of the observer.

  FIG. 11 is a schematic diagram for explaining the traveling direction of light in the second illumination unit 20 during horizontal 3D display. In particular, here, the traveling direction of the emitted light from the second illumination unit 20 synchronized with the image for the right eye in the horizontal 3D display is shown.

  The example shown in (A) in the figure corresponds to the case where the liquid crystal display panel LPN displays the second image at the second timing following the first timing for performing horizontal 3D display. In the horizontal 3D display, the second illumination unit 20 lights the third light source LS3 in synchronization with the liquid crystal display panel LPN displaying the second image. Radiated light from the third light source LS3 enters the second light guide plate LG2 from the third incident surface IN3 and travels along the second direction Y. The incident light is reflected by the second reflection pattern R2, travels in the negative direction of the first direction X, and is emitted from the second emission surface OUT2. That is, the direction of the emitted light emitted from the second emission surface OUT2 is a negative (−) direction in the first direction X corresponding to the left side of the observation position.

  As indicated by (B) in the figure, the emitted light emitted from the second emission surface OUT2 toward the left side in the figure (that is, in the negative direction of the first direction X) is reflected by the prism sheet 30 in the figure. Is reflected toward the right side (that is, in the positive direction of the first direction X). The reflected light reaches the liquid crystal display panel LPN displaying the right-eye image as the second image and is selectively transmitted by the liquid crystal display panel LPN. The light transmitted through the liquid crystal display panel LPN enters the right eye of the observer.

  The first timing and the second timing are repeated at 60 Hz, for example. That is, in synchronization with the liquid crystal display panel LPN displaying the left-eye image and the right-eye image alternately at 60 Hz, the first illumination unit 10 that functions as the left-eye surface light source and the second function that functions as the right-eye surface light source. The illumination units 20 alternately illuminate the liquid crystal display panel LPN. Thereby, a time division horizontal 3D display is realizable.

  FIG. 12 is a schematic diagram for explaining light traveling directions in the first illumination unit 10 and the second illumination unit 20 in vertical 3D display. When performing vertical 3D display, the positive (+) direction in the second direction Y corresponds to the left side of the observation position, and the negative (−) direction in the second direction Y corresponds to the right side of the observation position.

  The example shown in (A) in the figure corresponds to the case where the liquid crystal display panel LPN displays the first image at the first timing for performing vertical 3D display. In the vertical 3D display, the first lighting unit 10 lights the second light source LS2 in synchronization with the liquid crystal display panel LPN displaying the first image. The emitted light from the second light source LS2 enters the first light guide plate LG1 from the second incident surface IN2, and travels along the first direction X. The incident light is reflected by the first reflection pattern R1, travels in the negative direction of the second direction Y, and is emitted from the first emission surface OUT1. That is, the direction of the emitted light emitted from the first emission surface OUT1 is a negative direction in the second direction Y corresponding to the right side of the observation position.

  The outgoing light emitted from the first outgoing surface OUT1 is reflected toward the left side of the observation position by the prism sheet 30 as in the case of the horizontal 3D display. This reflected light is selectively transmitted by the liquid crystal display panel LPN displaying the left-eye image as the first image, and the transmitted light of the liquid crystal display panel LPN enters the left eye of the observer.

  The example shown in (B) in the figure corresponds to the case where the liquid crystal display panel LPN displays the second image at the second timing following the first timing for performing vertical 3D display. In the vertical 3D display, the second lighting unit 20 lights the fourth light source LS4 in synchronization with the liquid crystal display panel LPN displaying the second image. Radiated light from the fourth light source LS4 enters the second light guide plate LG2 from the fourth incident surface IN4 and travels along the first direction X. The incident light is reflected by the second reflection pattern R2, travels in the positive direction of the second direction Y, and is emitted from the second emission surface OUT2. That is, the direction of the emitted light emitted from the second emission surface OUT2 is a positive direction in the second direction Y corresponding to the left side of the observation position.

  The emitted light emitted from the second emission surface OUT2 is reflected toward the right side of the observation position by the prism sheet 30 as in the case of the horizontal 3D display. This reflected light is selectively transmitted by the liquid crystal display panel LPN displaying the right-eye image as the second image, and the transmitted light of the liquid crystal display panel LPN enters the right eye of the observer.

  The first timing and the second timing are repeated at 60 Hz, for example, and a time-division vertical 3D display can be realized.

  According to this embodiment, even when the display direction of the liquid crystal display device 1 is switched between the vertical direction and the horizontal direction, not only 2D display but also naked eye 3D display is possible. Further, during 2D display, there are light sources that are used and light sources that are not used depending on the display direction of the liquid crystal display device 1, but it is possible to improve the luminance by turning on the light source that is not used auxiliary. In addition, the viewing angle at which high luminance can be obtained can be enlarged.

  Moreover, according to the light guide plate applied in the present embodiment, it is possible to improve the light utilization efficiency. This will be described by taking the first reflection pattern R1 of the first light guide plate LG1 shown in FIG. 13 as an example.

  That is, the emitted light from the first light source LS1 enters the first light guide plate LG1 from the first incident surface IN1, and a part of the light is reflected by the first reflection pattern R1, but the other light is It reaches the end surface E1 of the first light guide plate LG1 without entering the first reflection surface RS1 of the first reflection pattern R1. In the present embodiment, the first light guide plate LG1 reflects light that has reached the end surface E1 of the first light guide plate LG1 without entering the first reflection surface RS1 toward the first reflection pattern R1 again. Designed. As a result, the light reflected by the end surface E1 of the first light guide plate LG1 returns in the opposite direction to the light incident from the first light source LS1, re-reflected by the vertical surface of the first reflection pattern R1, and incident from the first light source LS1. The light has the same direction as As a result, the reflected light reflected by the end surface E1 is reflected by the first reflecting surface RS1 of the first reflecting pattern R1 and the first emitting surface of the first light guide plate LG, similarly to the light incident from the first light source LS1. The light is emitted from OUT1 at a desired angle. Accordingly, it is possible to improve the light extraction efficiency from the first light guide plate LG1. In addition, as shown in FIG. 4, the shape of the reflection pattern is a quadrilateral shape in which one corner is a right angle and the lengths of two sides sandwiching the right angle are equal to each other. When the sides are installed in parallel with the first direction X and the second direction Y, respectively, and the shape viewed from each direction of the first direction X and the second direction Y is a right triangle shape, the light extraction efficiency is The improvement effect is maximized.

  As described above, according to this embodiment, a liquid crystal display device capable of horizontal 3D display and vertical 3D display can be provided.

  The transmissive liquid crystal display panel described in the above embodiment has a transmissive display function that selectively transmits illumination light from the first illumination unit 10 and the second illumination unit 20 to at least a part of the active area ACT. Any configuration may be used as long as it has, and a transflective liquid crystal display panel in which each pixel has a reflective portion and a transmissive portion is also included.

  In addition, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display device LPN ... Liquid crystal display panel AR ... Array substrate CT ... Opposite substrate LQ ... Liquid crystal layer 10 ... Illumination unit LS1 ... 1st light source LS2 ... 2nd light source LG1 ... 1st light guide plate 20 ... Illumination unit LS3 ... 3rd Light source LS4 ... Fourth light source LG2 ... Second light guide plate 30 ... Prism sheet

Claims (7)

A liquid crystal display panel having first long sides and second long sides parallel to each other, and first short sides and second short sides parallel to each other;
The liquid crystal display panel is disposed on the back side, and has a first emission surface facing the liquid crystal display panel side, a first incident surface aligned with the first long side, and a second incident surface aligned with the first short side. A first light guide plate; a first light source facing the first incident surface; and a second light source facing the second incident surface; and radiating light from the first light source or the second light source A first illumination unit that emits light from the first emission surface in a first direction and illuminates the liquid crystal display panel;
Arranged between the liquid crystal display panel and the first lighting unit, the second emission surface facing the liquid crystal display panel side, the third incident surface aligned with the second long side, and the second short side A second light guide plate having a fourth incident surface; a third light source facing the third incident surface; and a fourth light source facing the fourth incident surface. The third light source or the fourth light source. A second illumination unit that emits the emitted light from the second emission surface in a second direction different from the first direction and illuminates the liquid crystal display panel;
A liquid crystal display device comprising: The first light guide plate is emitted in the first direction from said first emission surface while reflecting the light incident in a direction toward the second incident surface from the first incidence surface, or the second incident A first reflection pattern that reflects the incident light incident from the surface in the direction toward the first incident surface and emits the light from the first emission surface in the first direction ;
The second light guide plate emits the incident light incident from the third incident surface in the second direction while reflecting the incident light toward the fourth incident surface in the second direction , or the fourth incident. 2. The second reflection pattern according to claim 1, further comprising: a second reflection pattern that emits light incident from a surface in the second direction while reflecting incident light in a direction toward the third incident surface. Liquid crystal display device.   The first reflection pattern and the second reflection pattern are triangular pyramid-shaped concave portions whose bottom surfaces are substantially right triangles, and the first reflection pattern is a first reflection facing the first incident surface side and the second incident surface side. 3. The liquid crystal display device according to claim 2, wherein the liquid crystal display device has a surface, and the second reflection pattern has a second reflection surface facing the third incident surface side and the fourth incident surface side. When performing the horizontal 3D display in a state where the first short side and the second short side of the liquid crystal display panel are located on the right side and the left side of the observation position, respectively, the liquid crystal display panel is used by the liquid crystal display panel as an observer. The first light source is turned on in synchronization with displaying the first image toward one of the eyes, and light is emitted from the first emission surface. The liquid crystal display panel of the second illumination unit is an observer The third light source is turned on in synchronization with displaying the second image toward the other eye of the second light, and light is emitted from the second emission surface,
When performing the vertical 3D display in a state where the first long side and the second long side of the liquid crystal display panel are positioned on the right side and the left side of the observation position, the liquid crystal display panel is used by the liquid crystal display panel as an observer. The second light source is turned on in synchronization with the display of the first image toward one of the eyes, and light is emitted from the first emission surface. The liquid crystal display panel of the second illumination unit is an observer 4. The liquid crystal display device according to claim 3, wherein the fourth light source is turned on in synchronization with displaying the second image toward the other eye, and light is emitted from the second emission surface. 5. .   And a prism sheet disposed between the liquid crystal display panel and the second illumination unit and having a plurality of square pyramid-shaped prisms disposed on a side facing the second illumination unit. Item 5. The liquid crystal display device according to any one of Items 1 to 4. The prism sheet is rectangular,
6. The liquid crystal display device according to claim 5, wherein each of the prisms has a square bottom surface, and four sides of the bottom surface are parallel to four sides of the prism sheet. Each of the prisms has a vertex on the side facing the second illumination unit;
The prism located at the center of the prism sheet has a vertical line extending from the apex to the bottom surface so that the vertical leg coincides with the center of gravity of the bottom surface, and the arrangement position of the prism becomes farther from the center of the prism sheet. The liquid crystal display device according to claim 6, wherein the liquid crystal display device is displaced toward the outside of the prism sheet from the center of gravity of the bottom surface.

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