JP2007052323A - Electrooptical device and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device which can be controlled at a viewing angle desired by a user irrespective of a viewing angle characteristic of a liquid crystal display panel itself. <P>SOLUTION: The electrooptical device which is, for example, a liquid crystal display device, is composed of a display panel such as liquid crystal display panel and a liquid crystal lens. The liquid crystal lens is concretely a liquid crystal lens sheet, is located on the visible side of the display panel, is interposed between a pair of substrates and a pair of substrates and has a liquid crystal layer consisting of nematic liquid crystal which changes the alignment state upon voltage application. The liquid crystal lens can refract light emitted from the display panel in the liquid crystal layer. Accordingly, by using the liquid crystal lens, the direction of light emitted from the display panel can be changed and the viewing angle can be changed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technical field of an electro-optical device such as a liquid crystal display device and an electronic apparatus including the same.

  In a liquid crystal display device, it is desired to have necessary viewing angle characteristics according to the purpose. For example, in a liquid crystal display device such as a mobile phone, the display screen only needs to be visible to the user. On the contrary, if the viewing angle is wide, there is a possibility that it may be seen by other people, which may not be preferable. On the other hand, a wide viewing angle is desirable for applications such as a liquid crystal television where many people watch at the same time.

  As a method of changing the viewing angle of a liquid crystal display device, a method of adjusting the alignment direction of liquid crystal molecules of a liquid crystal display panel is known. However, since this method is performed in the manufacturing process of the liquid crystal display panel, it cannot be adjusted after the liquid crystal display panel is completed.

  In Patent Document 1, a light collector is disposed between the liquid crystal display panel and the lighting device, and an optical compensator for specifying the refraction direction of light transmitted through the liquid crystal display panel is disposed on the light exit surface of the liquid crystal display panel. By doing so, a specific viewing angle is obtained.

JP-A-7-104271

  The present invention has been made in view of the above points, and an object thereof is to provide a liquid crystal display device that can be adjusted to a viewing angle desired by a user regardless of the viewing angle characteristics of the liquid crystal display panel itself.

  In one aspect of the present invention, the electro-optical device is disposed on the viewing side of the display panel and the display panel, is sandwiched between the pair of substrates and the pair of substrates, and changes the alignment state when a voltage is applied. And a liquid crystal lens having a liquid crystal layer made of nematic liquid crystal.

  The electro-optical device is, for example, a liquid crystal display device, and includes a display panel such as a liquid crystal display panel and a liquid crystal lens. Specifically, the liquid crystal lens is a liquid crystal lens sheet, which is disposed on the viewing side of the display panel, is sandwiched between a pair of substrates, and the nematic liquid crystal that is sandwiched between the pair of substrates and changes the alignment state when a voltage is applied. A liquid crystal layer. The liquid crystal lens can refract light emitted from the display panel in a liquid crystal layer. Therefore, by using a liquid crystal lens, the direction of light emitted from the display panel can be changed, and the viewing angle can be changed.

  In a preferred embodiment of the electro-optical device, a display panel, an illumination device that illuminates the display panel by transmitting light, and a pair of substrates disposed on the display panel side of the illumination device, And a liquid crystal lens having a liquid crystal layer made of nematic liquid crystal that is sandwiched between the pair of substrates and changes the alignment state when a voltage is applied.

  In one aspect of the electro-optical device, the liquid crystal lens includes a plurality of control electrodes formed in stripes on the inner surface of at least one of the pair of substrates. In this way, the optical effects of both the convex lens and the concave lens can be realized on the liquid crystal layer only by controlling the magnitude of the voltage applied to the plurality of control electrodes. The width of the viewing angle of the apparatus can be controlled.

  In another aspect of the electro-optical device, a voltage applied to a plurality of control electrodes arranged on one subpixel becomes closer to a position closer to the center of the subpixel. Is set higher and the applied voltage is set lower as the control electrode is located closer to both ends of the sub-pixel. By doing so, the optical effect of the convex lens can be given to the liquid crystal layer, and the viewing angle of the electro-optical device can be narrowed.

  In another aspect of the electro-optical device, a voltage applied to a plurality of control electrodes arranged on one subpixel becomes closer to a position closer to the center of the subpixel. Is set lower and the applied voltage is set higher as the control electrode is arranged at a position closer to both ends of the sub-pixel. By doing so, the liquid crystal layer can have the optical effect of a concave lens, and the viewing angle of the electro-optical device can be widened.

  In another aspect of the above electro-optical device, the width of the plurality of control electrodes arranged on one subpixel becomes larger as the control electrode is arranged at a position closer to the center of the subpixel. The width of the control electrode formed becomes smaller as the control electrode is formed and arranged closer to both ends of the sub-pixel. By doing so, the optical effect of the convex lens can be given to the liquid crystal layer, and the viewing angle of the electro-optical device can be narrowed. In addition, since the values of currents flowing through the plurality of control electrodes can all be made equal, the control of the drive circuit can be simplified.

  In another aspect of the above electro-optical device, the width of the plurality of control electrodes arranged on one subpixel becomes smaller as the control electrode is arranged at a position closer to the center of the subpixel. The width of the control electrode is increased as the control electrode is formed and disposed at a position closer to both ends of the sub-pixel. By doing so, the liquid crystal layer can have the optical effect of a concave lens, and the viewing angle of the electro-optical device can be widened. In addition, since the values of currents flowing through the plurality of control electrodes can all be made equal, the control of the drive circuit can be simplified.

  In another aspect of the electro-optical device, the liquid crystal lens includes a base layer formed on at least one of the pair of substrates on the liquid crystal layer side of one substrate or the liquid crystal layer side of the other substrate. A concave curved surface is formed for each sub-pixel unit on the liquid crystal layer side of the base layer, and the liquid crystal layer is a control electrode formed on the liquid crystal layer side of the one substrate. And a voltage is applied by the control electrode formed on the liquid crystal layer side of the other substrate. Here, the underlayer specifically refers to a protective layer. Even in this case, the optical effect of the convex lens can be given to the liquid crystal layer, and the viewing angle of the electro-optical device can be narrowed.

  In another aspect of the electro-optical device, the liquid crystal lens includes a base layer formed on at least one of the pair of substrates on the liquid crystal layer side of one substrate or the liquid crystal layer side of the other substrate. A convex curved surface is formed for each sub-pixel unit on the liquid crystal layer side of the base layer, and the liquid crystal layer is a control electrode formed on the liquid crystal layer side of the one substrate. And a voltage is applied by the control electrode formed on the liquid crystal layer side of the other substrate. Even in this case, the optical effect of the concave lens can be given to the liquid crystal layer, and the viewing angle of the electro-optical device can be widened.

  In another aspect of the electro-optical device, the liquid crystal lens includes a first base layer formed on the liquid crystal layer side of one of the pair of substrates, and the liquid crystal layer side of the other substrate. A second underlayer is formed on the liquid crystal layer side of the first underlayer and on the liquid crystal layer side of the second underlayer, and a concave curved surface is formed for each sub-pixel unit. The liquid crystal layer is applied with a voltage by a control electrode formed on the liquid crystal layer side of the one substrate and a control electrode formed on the liquid crystal layer side of the other substrate. . Even in this case, the optical effect of the convex lens can be given to the liquid crystal layer, and the viewing angle of the electro-optical device can be narrowed.

  In another aspect of the electro-optical device, the liquid crystal lens includes a first base layer formed on the liquid crystal layer side of one of the pair of substrates, and the liquid crystal layer side of the other substrate. A second underlayer is formed, and a convex curved surface is formed for each sub-pixel unit on the liquid crystal layer side of the first underlayer and on the liquid crystal layer side of the second underlayer. The liquid crystal layer is applied with a voltage by a control electrode formed on the liquid crystal layer side of the one substrate and a control electrode formed on the liquid crystal layer side of the other substrate. . Even in this case, the optical effect of the concave lens can be given to the liquid crystal layer, and the viewing angle of the electro-optical device can be widened.

  In still another aspect of the present invention, an electronic apparatus including the above liquid crystal display device in a display portion can be configured.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the present invention is applied to a liquid crystal display device.

[Liquid Crystal Display]
FIG. 1 is a side view showing a schematic configuration of a liquid crystal display device 100 including a liquid crystal lens sheet 30 of the present invention. In FIG. 1, for convenience of explanation, each component is illustrated with a space therebetween, but actually, the liquid crystal display device 100 is configured in a state where they are stacked in the vertical direction in the drawing.

  The liquid crystal display device 100 mainly includes a liquid crystal display panel 20, a lighting device 10 that illuminates the liquid crystal display panel 20, and a liquid crystal lens sheet 30 that refracts light emitted from the liquid crystal display panel 20.

  The liquid crystal display panel 20 is configured by bonding a lower substrate 1 and an upper substrate 2 such as glass together with a sealing material 3 to form a cell structure, and enclosing the liquid crystal 4 therein. Further, the liquid crystal display panel 20 is formed with many other components such as a black matrix, a color filter, an electrode, and the like in a matrix (lattice) or stripe (line). These components are formed substantially in parallel on the four sides of the normally rectangular liquid crystal display panel 20. In the present invention, the structure of the liquid crystal display panel 20 is not particularly limited.

  The illumination device 10 is disposed on the lower surface side of the liquid crystal display panel 20 and includes a light source unit 15 and a light guide plate 11. The light source unit 15 includes a plurality of LEDs 16 that are point light sources. The light L emitted from each LED 16 enters the light guide plate 11 as shown in the figure, and changes its direction by repeating reflection on the upper and lower surfaces of the light guide plate 11, thereby changing the upper and lower surfaces of the light guide plate 11 and the critical angle of the light L. If it exceeds, light will be emitted from the upper and lower surfaces of the light guide plate 11. The light L emitted from the lower surface of the light guide plate 11 is reflected by the reflection sheet 14 disposed on the lower surface side of the light guide plate 11 and returns to the light guide plate 11 again. Between the liquid crystal display panel 20 and the illumination device 10, there are provided a diffusion sheet 13 that diffuses light, a prism sheet 12 that directs light to the liquid crystal display panel 20, and the like, and the light L emitted from the upper surface of the light guide plate 11. Illuminates the liquid crystal display panel 20 through these sheets.

  A liquid crystal lens sheet 30 is provided on the outer surface of the upper substrate 2 of the liquid crystal display panel 20, that is, on the surface where the light L of the liquid crystal display panel 20 is emitted. The light L emitted from the liquid crystal display panel 20 passes through the liquid crystal lens sheet 30. The liquid crystal lens sheet 30 has a liquid crystal layer. By transmitting the light L through the liquid crystal layer, the light L can be refracted and the traveling direction of the light L can be changed. That is, by using the liquid crystal lens sheet 30, the viewing angle and the brightness of the liquid crystal display device 100 can be controlled regardless of the viewing angle characteristics of the liquid crystal display panel 20 itself. Thus, the light L transmitted through the liquid crystal lens sheet 30 is visually recognized by an observer.

  Further, as will be described in detail later, external light transmitted through the liquid crystal lens sheet 30 and the liquid crystal display panel 20 is reflected by the reflection sheet 14 of the lighting device 10. The liquid crystal display panel 20 is also illuminated by external light reflected by the reflecting sheet 14.

[First embodiment]
First, the structure of the liquid crystal lens sheet 30 according to the first embodiment will be described. FIG. 2 is a plan view of the liquid crystal lens sheet 30, and mainly shows the wiring configuration of the liquid crystal lens sheet 30. FIG. 3 is a cross-sectional view of the liquid crystal lens sheet 30.

  In FIG. 2, the upper substrate 32 of the liquid crystal lens sheet 30 is disposed on the front side (observation side) of the paper, and the lower substrate 31 of the liquid crystal lens sheet 30 is disposed on the back side of the paper. In FIG. 2, the vertical direction (column direction) of the paper surface is defined as the Y direction, and the horizontal direction (row direction) of the paper surface is defined as the X direction. In FIG. 2, a unit pixel that displays one color in the liquid crystal display panel 20 is shown as a sub-pixel SG. In addition, the 1 × 3 sub-pixel region SG indicates one pixel region AG composed of R (red), G (green), and B (blue) in the liquid crystal display panel 20. Here, it is needless to say that the liquid crystal display panel 20 is not limited to the one that performs color display, but may be the one that performs monochrome display instead.

  As shown in FIG. 3, the liquid crystal lens sheet 30 is formed by bonding an upper substrate 32 and a lower substrate 31 disposed so as to face the upper substrate 32 through a frame-shaped sealing material 33. A liquid crystal layer 34 is formed by sealing liquid crystal inside 33. Here, as the liquid crystal sealed as the liquid crystal layer 34, nematic liquid crystal that is vertically aligned when a voltage is applied is used.

  First, the planar configuration of the lower substrate 31 will be described. On the inner surface of the lower substrate 31, a plurality of control electrodes 37, a driver IC 40, an external connection wiring 35, an FPC (Flexible Printed Circuit) 41, and the like are mainly formed or mounted.

  As shown in FIG. 2, the lower substrate 31 has an extended region 31a that extends outward from one side of the upper substrate 32, and a driver IC 40 is mounted on the extended region 31a. A terminal (not shown) on the input side of the driver IC 40 is electrically connected to one end side of the plurality of external connection wirings 35, and the other end side of the plurality of external connection wirings 35 is electrically connected to the FPC 41. It is connected. Each control electrode 37 is formed so as to extend in the Y direction and at an appropriate interval in the X direction, and a plurality of control electrodes 37 are formed in stripes in one sub-pixel SG. In FIG. 2 and FIG. 3, as an example, five control electrodes 37 are formed in a stripe shape in one sub-pixel SG. One end of each control electrode 37 is electrically connected to an output terminal (not shown) of the driver IC 40. Each control electrode 37 is formed of a transparent conductive material such as ITO (Indium-Tin Oxide). A protective layer 39 is formed on the inner surface of each control electrode 37.

  In the liquid crystal lens sheet 30, a region V (a region surrounded by a two-dot chain line) in which a plurality of pixel regions AG are arranged in a matrix in the X direction and the Y direction corresponds to an effective display region in the liquid crystal display panel 20. . In the effective display area V, images such as letters, numbers, and figures are displayed.

  Next, the planar configuration of the upper substrate 32 will be described. The upper substrate 32 has a common electrode 38. The common electrode 38 is made of a transparent conductive material such as ITO, and is formed over substantially the entire surface of the upper substrate 32. The common electrode 38 is electrically connected to one end side of the wiring 36 in the corner area E1 of the sealing material 33, and the other end side of the wiring 36 is electrically connected to an output terminal corresponding to the COM of the driver IC 40. It is connected to the.

  Liquid crystal alignment films 42 and 43 are formed on the inner surface of the protective layer 39 of the lower substrate 31 and on the inner surface of the common electrode 38 of the upper substrate 32, respectively.

  In the liquid crystal lens sheet 30 having the above-described configuration, a signal corresponding to a viewing angle and luminance desired to be set in the liquid crystal display device 100 by the driver IC 40 based on a signal and power from the FPC 41 connected to an electronic device or the like, , Sn-1, and Sn (n is a natural number) corresponding to the control electrodes 37 respectively corresponding to S1, S2,. Thereby, the alignment state of the liquid crystal layer 34 is controlled.

(Viewing angle control method using liquid crystal lens sheet)
Next, a method for performing viewing angle control using the liquid crystal lens sheet 30 will be described in detail. First, a method for narrowing the viewing angle using the liquid crystal lens sheet 30 will be described. FIG. 4A is an enlarged cross-sectional view of the liquid crystal lens sheet 30 in the sub pixel SG unit when the viewing angle is narrowed, and is an enlarged view of a portion surrounded by a broken line 30p in FIG.

  When viewed in units of subpixels SG, as described above, the plurality of control electrodes 37 are formed on the lower substrate 31 in stripes. In FIG. 4A, it is assumed that five control electrodes 37 composed of S1, S2,..., S5 are formed on the lower substrate 31 in units of subpixels SG. The alignment film 42 and the alignment film 43 are subjected to rubbing for tilting (tilting) the liquid crystal molecules 45 in a single direction (the direction of the broken arrow til in FIG. 4A).

  When no voltage is applied between the control electrodes 37 and the common electrode 38, that is, when no voltage is applied, the liquid crystal molecules 45 have a major axis direction in which the alignment film 42 and the alignment film 43 are rubbed. On the other hand, it is in a state of being completely parallel. In other words, the liquid crystal molecules 45 are “sleeping” with respect to the lower substrate 31 and the upper substrate 32. On the other hand, when a voltage is applied between the control electrodes 37 and the common electrode 38 of S1 to S5, the magnitude of the voltage applied by the driver IC 40 to the control electrode 37 of S3 formed at the center of the subpixel SG is small. The magnitude of the voltage applied to the control electrode 37 is maximized and goes in the direction from the center of the sub-pixel SG to both ends (the direction in which the control electrodes 37 of S1 and S5 are formed in FIG. 4A). Is gradually reduced. Therefore, in FIG. 4A, the relationship of the magnitude of the voltage applied to the control electrode 37 of S1 to S5 is established as S3> S2≈S4> S1≈S5. By doing so, the liquid crystal molecules 45 at the center of the sub-pixel SG can be made to stand vertically with respect to the lower substrate 31 and the upper substrate 32, and are directed toward both ends of the sub-pixel SG. Accordingly, the tilt (tilt angle) of the liquid crystal molecules 45 with respect to the lower substrate 31 and the upper substrate 32 can be reduced stepwise.

  Next, optical characteristics of the liquid crystal layer 34 when the voltage shown in FIG. 4A is applied will be described. The refractive index of light of the liquid crystal layer 34 is the average refractive index of the liquid crystal molecules 45 through which the light L is transmitted. In the nematic liquid crystal, since the liquid crystal molecules 45 have birefringence, the refractive index differs between the major axis direction of the liquid crystal molecules 45 and the minor axis direction perpendicular thereto, and the refractive index in the major axis direction is the refractive index in the minor axis direction. Bigger than. As described above, the liquid crystal molecules 45 are standing in the center of the sub-pixel SG, but the liquid crystal molecules 45 are inclined with respect to the lower substrate 31 and the upper substrate 32 toward both ends of the sub-pixel SG. It becomes close to a small state, that is, a sleeping state. That is, at the center of the sub-pixel SG, the refractive index of the liquid crystal layer 34 is close to the refractive index in the major axis direction of the liquid crystal molecules 45, and at both ends of the sub-pixel SG, the refractive index of the liquid crystal layer 34 is It becomes close to the refractive index in the minor axis direction. From this, the refractive index of the light of the liquid crystal layer 34 is not uniform, and differs depending on the liquid crystal layers 34n1 to 34n5 in the portions corresponding to the respective control electrodes 37 of S1 to S5. Specifically, assuming that the refractive indexes of the light of the liquid crystal layers 34n1 to 34n5 corresponding to the control electrodes 37 of S1 to S5 are refractive indexes n1 to n5, the relationship of n3> n2≈n4> n1≈n5 is established. To do. Therefore, the liquid crystal layer 34 when the voltage shown in FIG. 4A is applied becomes a so-called gradient index lens having the same optical effect as the convex lens 46 shown in FIG. 4B.

  In summary, as the control electrode 37 is located closer to the center of the sub-pixel SG, the applied voltage is set higher, and as the control electrode 37 is located closer to both ends of the sub-pixel SG, By setting the applied voltage low, the liquid crystal layer 34 can be a refractive index distribution lens having the same optical effect as the convex lens. In this way, the light incident on the liquid crystal layer 34 can be refracted in the direction of condensing, and the viewing angle in the ± X direction of the liquid crystal display device 100 can be narrowed.

  Next, a method for widening the viewing angle using the liquid crystal lens sheet 30 will be described. FIG. 5A is an enlarged cross-sectional view in units of subpixels SG in the liquid crystal lens sheet 30 when the viewing angle is widened.

  In a state where no voltage is applied between each control electrode 37 and the common electrode 38, the liquid crystal molecules 45 are lying on the lower substrate 31 or the upper substrate 32. On the other hand, when a voltage is applied between each control electrode 37 and the common electrode 38, the magnitude of the voltage applied by the driver IC 40 to the control electrodes 37 of S1 and S5 formed at both ends of the subpixel SG is maximized. The voltage applied to the control electrode 37 is gradually reduced toward the center of the subpixel SG, and the voltage applied to the control electrode 37 in the center of the subpixel SG, that is, the control electrode 37 of S3. The size of is minimized. Therefore, in FIG. 5A, the relationship of S3 <S2≈S4 <S1≈S5 is established as the magnitude of the voltage applied to the control electrodes 37 of S1 to S5. By doing so, as shown in FIG. 5A, the liquid crystal molecules 45 at both ends of the sub-pixel SG can be made to stand vertically with respect to the lower substrate 31 and the upper substrate 32. The tilt angle of the liquid crystal molecules 45 can be reduced step by step toward the center of the subpixel SG.

  Next, the optical characteristics of the liquid crystal layer 34 when the state shown in FIG. At this time, the liquid crystal molecules 45 are in a standing state at both ends of the subpixel SG, but the liquid crystal molecules 45 are in a state in which the inclination with respect to the lower substrate 31 and the upper substrate 32 becomes smaller toward the center of the subpixel SG. That is, it becomes close to a sleeping state. That is, at both ends of the sub-pixel SG, the refractive index of light of the liquid crystal layer 34 is close to the refractive index in the major axis direction of the liquid crystal molecules 45, and at the center of the sub-pixel SG, the refractive index of the liquid crystal layer 34 is It becomes close to the refractive index in the minor axis direction of 45. Therefore, also in the case of FIG. 5A, the refractive index of light of the liquid crystal layer 34 is not uniform and varies depending on the liquid crystal layers 34n1 to 34n5 corresponding to the respective control electrodes 37 of S1 to S5. Specifically, assuming that the refractive indexes of the light of the liquid crystal layers 34n1 to 34n5 corresponding to the control electrodes 37 of S1 to S5 are the refractive indexes n1 to n5, respectively, there is a relationship of n3 <n2≈n4 <n1≈n5. To establish. Accordingly, the liquid crystal layer 34 when the voltage shown in FIG. 5A is applied becomes a so-called refractive index distribution lens having the same optical effect as the concave lens 47 shown in FIG. 5B.

  In summary, as the control electrode 37 is located closer to both ends of the subpixel SG, the applied voltage is set higher, and as the control electrode 37 is located closer to the center of the subpixel SG, By setting the applied voltage low, the liquid crystal layer 34 can be a refractive index distribution lens having the same optical effect as the concave lens. By doing so, the light incident on the liquid crystal layer 34 can be refracted in the diffusing direction, and the viewing angle in the ± X direction of the liquid crystal display device 100 can be widened.

  In the liquid crystal lens sheet 30 according to the first embodiment, the orientation of the liquid crystal molecules 45 in the liquid crystal layer 34 is changed by controlling the magnitude of the voltage applied to each control electrode 37, so that both the convex lens and the concave lens are used. It can be seen that the functions can be switched and the viewing angle can be controlled. For example, when a VA (Vertical Alignment) type or IPS (In Plane Switching) type liquid crystal display panel is used as the liquid crystal display panel 20, the viewing angle of the liquid crystal display device 100 becomes wide. At this time, when it is desired to narrow the viewing angle for reasons such as not wanting to peep, the applied voltage is set higher as the control electrode 37 is located closer to the center of the subpixel SG. The applied voltage is set lower as the control electrode 37 is located closer to both ends of the pixel SG. Thus, the viewing angle of the liquid crystal display device 100 can be narrowed by switching the function of the liquid crystal lens sheet 30 to the function of a convex lens.

  For example, when the prism sheet 12 is an inverted prism sheet whose prism shape is directed toward the lighting device 10, the light incident on the liquid crystal display panel 20 becomes light having a high light collecting property, and the liquid crystal display device The viewing angle of 100 is very narrow. At this time, when it is desired to widen the viewing angle, the applied voltage is set higher as the control electrode 37 is located closer to both ends of the subpixel SG, and the control electrode 37 is placed closer to the center of the subpixel SG. The closer the control electrode 37 is, the lower the applied voltage is set. Thus, the viewing angle of the liquid crystal display device 100 can be widened by switching the function of the liquid crystal lens sheet 30 to the function of a concave lens.

  In the liquid crystal display device 100, the liquid crystal display panel 20 is also illuminated by reflecting external light incident on the liquid crystal display device 100 by the reflection sheet 14 of the illumination device 10. Therefore, by switching the function of the liquid crystal lens sheet 30 to the function of a convex lens, external light can be condensed toward the reflection sheet 14 and the brightness of the liquid crystal display device 100 can be increased. On the other hand, by switching the function of the liquid crystal lens sheet 30 to the function of a concave lens, external light can be diffused toward the reflection sheet 14 and the luminance of the liquid crystal display device 100 can be lowered. Thus, by using the liquid crystal lens sheet 30, the luminance of the liquid crystal display panel 20 can be controlled.

  It should be noted that the voltage applied to the control electrode 37 of S1 is maximized, the voltage applied to the control electrode 37 is gradually reduced in the X direction, and the voltage applied to the common electrode of S5 is minimized. Thus, it is possible to narrow only the viewing angle in the −X direction. In addition, the voltage applied to the control electrode 37 of S5 is maximized, the voltage applied to the control electrode 37 is gradually reduced in the -X direction, and the voltage applied to the control electrode 37 of S1 is minimized. By doing so, it is possible to narrow only the viewing angle in the X direction.

(Modification)
Next, a modified example of the liquid crystal lens sheet 30 will be described. FIG. 6 is a plan view of the first modification of the liquid crystal lens sheet 30 in units of subpixels SG. As shown in FIG. 6, unlike the first embodiment, the control electrodes 37 of S1 to S5 have structures having different widths. In FIG. 6A, as an example, the width of the control electrode 37 of S3 which is the center of the subpixel SG is maximized, and the width of the control electrodes 37 of S1 and S5 at both ends of the subpixel SG is minimized. That is, if the widths of the control electrodes 37 of S1 to S5 are w1 to w5, respectively, the relationship of w3>w2≈w4> w1≈w5 is established. Since the internal resistance of the control electrode 37 is proportional to the size of the common electrode, increasing the width of the control electrode 37 increases the internal resistance accordingly. Therefore, by adopting the structure shown in FIG. 6A by the control electrode 37 of S1 to S5, even if all the values of the current flowing through the control electrode 37 of S1 to S5 are all equal, it is applied to the control electrode 37 of S3. The voltage applied to the control electrodes 37 of S1 and S5 can be minimized. As described above, among the control electrodes 37 disposed on the subpixel SG, the width of the control electrode 37 disposed closer to the center of the subpixel SG is increased, and the width of the control electrode 37 is closer to both ends of the subpixel SG. Even if the value of the current passed through each control electrode 37 is made equal by forming the width of the control electrode 37 so as to be closer to the position, the convex shape is the same as described with reference to FIG. The liquid crystal layer 34 can have the same optical effect as the lens.
On the other hand, for the same reason as described above, as shown in FIG. 6B, among the control electrodes 37 disposed on the subpixel SG, the control electrodes 37 disposed at positions close to both ends of the subpixel SG. The width is formed to be larger, and the width is formed to be smaller as the control electrode 37 is arranged at a position closer to the center of the sub-pixel SG (in relation to FIG. 6B, w3 <w2 ≒ w4 <w1 ≒ w5) Even if the value of the current passed through each control electrode 37 is equal, the liquid crystal layer 34 has the same optical effect as the concave lens, as described with reference to Fig. 5A. Can be made.
As described above, in the liquid crystal lens sheet 30 according to the first modification shown in FIGS. 6A and 6B, even if all the values of the currents flowing through the control electrodes 37 of S1 to S5 are equal, the convexity It can have the optical effect of a mold lens or a concave lens. In other words, in the case where the liquid crystal layer 34 has the optical effect of the convex lens or the concave lens, in the first modification, the value of the current passed through each control electrode 37 can be made equal, so that the drive circuit is controlled. Can be simple.

  FIG. 7 is a plan view in units of subpixels SG showing a second modification of the liquid crystal lens sheet 30. In the second modification, the control electrodes 37 of S1 to S5 have a concentric shape. Here, in order to electrically connect with the driver IC 40, as shown in FIG. 7, wirings are drawn from the respective control electrodes 37 of S1 to S5. As described above, the control electrode 37 of S1 to S5 has a concentric structure, so that the liquid crystal layer 34 can have the function of a spherical lens, and not only the viewing angle in the ± X direction but also the ± Y direction. The viewing angle can be changed at the same time.

  Note that the structure in which the wiring is routed from each of the control electrodes 37 of S1 to S5 may be a complicated structure because the subpixel SG itself is very small. Accordingly, instead of adopting a structure in which the control electrodes 37 of S1 to S5 are arranged on the same plane and the wiring is routed, a layer structure in which the control electrodes 37 of S1 to S5 are arranged in an overlapping manner can be used. It is also possible to use a layer structure and not a routing structure.

[Second Embodiment]
Next, the configuration of the liquid crystal lens sheets 30a and 30b according to the second embodiment will be described.

  First, the configuration of the liquid crystal lens sheet 30a will be described. FIG. 8 shows a plan view of a liquid crystal lens sheet 30a according to the second embodiment. FIG. 9 is a cross-sectional view of the liquid crystal lens sheet 30a.

  In FIG. 8, the upper substrate 32 of the liquid crystal lens sheet 30a is disposed on the front side (observation side) of the paper, and the lower substrate 31 of the liquid crystal lens sheet 30a is disposed on the back side of the paper.

  As shown in FIG. 9, the liquid crystal lens sheet 30a is formed by bonding a lower substrate 31 and an upper substrate 32 disposed to face the lower substrate 31 with a frame-shaped sealing material 33 therebetween. A liquid crystal layer 34 is formed by sealing liquid crystal inside the material 33. Here, as the liquid crystal sealed as the liquid crystal layer 34, nematic liquid crystal that is vertically aligned when a voltage is applied is used as in the liquid crystal lens sheet 30 according to the first embodiment.

  The lower substrate 31 has a control electrode 37a. In the liquid crystal lens sheet 30 according to the first embodiment, the control electrode 37 is formed in a stripe shape in the y direction. However, in the liquid crystal lens sheet 30a according to the second embodiment, the control electrode 37a is in a stripe shape. Instead of being formed, the substrate is formed over substantially the entire surface of the lower substrate 31. The control electrode 37a is electrically connected to one end side of the wiring 36b in the corner area E2 of the sealing material 33, and the other end side of the wiring 36b is electrically connected to an output terminal corresponding to COM2 of the driver IC 40. It is connected to the.

  The upper substrate 32 has a common electrode 38. The common electrode 38 is formed over substantially the entire surface of the upper substrate 32. The common electrode 38 is electrically connected to one end side of the wiring 36a in the corner area E1 of the sealing material 33, and the other end side of the wiring 36a is electrically connected to an output terminal corresponding to COM of the driver IC 40. It is connected to the.

  Protective layers 51 and 52 are formed on the inner surface of the control electrode 37a and the inner surface of the common electrode 38 using a resin or the like as a material, respectively. In the liquid crystal lens sheet 30a, as shown in FIG. 9, the protective layers 51 and 52 are provided with irregularities. Specifically, when viewed in units of subpixels SG, the inner surface of the protective layer 51 is formed into a concave curved surface, and the inner surface of the protective layer 52 is also formed into a concave curved surface. Alignment films 53 and 54 are formed on the inner surface of the protective layer 51 and on the inner surface of the protective layer 52, respectively. It should be noted that the control electrode 37a and the protective layer 51, and the control electrode 38 and the protective layer 52 may be stacked in any order.

  FIG. 10A is a cross-sectional view of the liquid crystal lens sheet 30a in units of subpixels SG when a voltage is applied between the control electrodes 37a and 38. In FIG. 9, an enlarged view of a portion surrounded by a broken line 30ap. It is. When a voltage is applied between the control electrodes 37a and 38, the liquid crystal molecules 45 stand substantially perpendicular to the surfaces of the protective layers 51 and 52 as shown in FIG. Since the inclination of the liquid crystal molecules 45 hardly changes at the center and both ends of the sub-pixel SG, it can be considered that the light refractive index of the entire liquid crystal layer 34 is uniform. However, the thickness of the liquid crystal layer 34 varies greatly between the center and both ends of the sub-pixel SG. If the thickness of the liquid crystal layer 34 at the center of the subpixel SG is dc and the thickness of the liquid crystal layer 34 at both ends of the subpixel SG is dv, then dc> dv, and the liquid crystal layer extends from the center of the subpixel SG toward both ends. The thickness of the layer 34 gradually decreases from dc to dv. Therefore, the optical characteristic of the liquid crystal layer 34 in the liquid crystal lens sheet 30a shows the same optical characteristic as that of the convex lens 56 shown in FIG. 10B, that is, the characteristic of condensing the light L emitted from the liquid crystal display panel. It can be said. That is, by using the liquid crystal lens sheet 30a, the liquid crystal layer 34 can have the same optical effect as that of the convex lens 56. Therefore, the light L can be condensed to narrow the viewing angle in the ± X direction. it can.

  Next, the case where the liquid crystal lens sheet 30b is used will be described. FIG. 11 is a cross-sectional view of the liquid crystal lens sheet 30b. The liquid crystal lens sheet 30b differs from the liquid crystal lens sheet 30a only in the shapes of the protective layers 51 and 52 and the alignment films 53 and 54, and the other configurations are completely the same.

  Also in the liquid crystal lens sheet 30b, as shown in FIG. 11, the protective layers 51 and 52 are provided with irregularities. Specifically, when viewed in units of subpixels SG, the inner surface of the protective layer 51 is formed in a convex curved surface, and the inner surface of the protective layer 52 is also formed in a convex curved surface. Alignment films 53 and 54 are formed on the inner surface of the protective layer 51 and on the inner surface of the protective layer 52, respectively.

  FIG. 12A is a cross-sectional view of the liquid crystal lens sheet 30b in units of subpixels SG when a voltage is applied between the control electrodes 37a and 38. In FIG. 11, an enlarged view of a portion surrounded by a broken line 30bp. It is. When a voltage is applied between the control electrodes 37a and 38, the liquid crystal molecules 45 stand substantially perpendicular to the surfaces of the protective layers 51 and 52 as shown in FIG. Even in this case, since the inclination of the liquid crystal molecules 45 hardly changes at the center and both ends of the sub-pixel SG, it can be considered that the light refractive index of the entire liquid crystal layer 34 is uniform. However, the thickness of the liquid crystal layer 34 varies greatly between the center and both ends of the sub-pixel SG. Here, when the thickness of the liquid crystal layer 34 at the center of the sub-pixel SG is dc and the thickness of the liquid crystal layer 34 at both ends of the sub-pixel SG is dv, dc <dv, and the distance from the center of the sub-pixel SG toward both ends is increased. Thus, the thickness of the liquid crystal layer 34 gradually increases from dc to dv. Therefore, it can be said that the optical characteristic of the liquid crystal layer 34 in the liquid crystal lens sheet 30b shows the same optical characteristic as the concave lens 57 shown in FIG. 12B, that is, the characteristic of diffusing the light L emitted from the liquid crystal display panel. . That is, by using the liquid crystal lens sheet 30b, the liquid crystal layer 34 can have the same optical effect as the concave lens 57, so that the light L can be diffused to widen the viewing angle in the ± X direction.

  In the liquid crystal lens sheets 30a and 30b according to the second embodiment, since the liquid crystal layer 34 has the lens effect as described above, the light refractive index of the protective layers 51 and 52 is between the control electrodes 37a and 38. When no voltage is applied, that is, when no voltage is applied, the refractive index of the light of the liquid crystal layer 34 is approximately equal, and when a voltage is applied between the control electrodes 37a and 38, the light of the liquid crystal layer 34 is transmitted. It needs to be smaller than the refractive index. Therefore, the protective layers 51 and 52 preferably have a refractive index equal to the refractive index in the minor axis direction of the liquid crystal molecules of the liquid crystal layer 34.

  Further, as described in the liquid crystal lens sheet 30 according to the first embodiment, by using the liquid crystal lens sheet 30a having the function of a convex lens, it is possible to collect external light, and thus the liquid crystal display device 100. Can increase the brightness. By using the liquid crystal lens sheet 30b having the function of a concave lens, it is possible to diffuse external light, so that the luminance of the liquid crystal display device 100 can be lowered.

[Modification]
In the liquid crystal lens sheets 30a and 30b according to the second embodiment, both the protective layers 51 and 52 are formed with concave and convex curved surfaces, respectively. However, instead of forming a concave and convex curved surface on both of the protective layers 51 and 52, a protective layer may be provided on one of the lower substrate 31 and the upper substrate 32 to form a concave and convex curved surface. In addition, the same optical effect as that of the convex lens or the concave lens can be obtained. As an example, a case where a concave curved surface is formed on the upper substrate 32 will be described below.

  13 and 14 show a liquid crystal lens sheet 30c according to a first modification of the second embodiment. The liquid crystal lens sheet 30c is a modification of the liquid crystal lens sheet 30a, and the protective layer 52 is provided only on the upper substrate 32, and a concave curved surface is formed. Therefore, the liquid crystal layer 34 becomes a single-sided convex lens. By doing so, as is clear from the path of the light L shown in FIG. 13, the light L can be collected and the viewing angle in the ± X direction can be narrowed. Further, as shown in the path of the light Lin shown in FIG. 14, external light can be collected. Thus, the liquid crystal lens sheet 30c according to the modification can obtain the same optical effect as the liquid crystal lens sheet 30a.

  FIG. 15 shows a liquid crystal lens sheet 30d according to a second modification of the second embodiment. In the liquid crystal lens sheet 30d, the concave curved surface formed in the protective layer 52 is formed over a position corresponding to the black matrix BM of the liquid crystal display panel 20. Therefore, the liquid crystal layer 34 is a single-sided convex lens that is located at a position corresponding to the black matrix BM. The black matrix BM is for preventing light from being mixed from one subpixel SG to the other subpixel SG in the liquid crystal display panel 20, and is formed between the subpixels SG of the liquid crystal display panel 20. . By using the liquid crystal lens sheet 30d, in addition to the optical effects of the liquid crystal lens sheet 30c, the external light incident on the black matrix BM is displayed in the sub-pixels of the liquid crystal display panel 20 as indicated by the path of the light Linb. It can be condensed inside. That is, conventionally, external light that is absorbed by the black matrix BM when it reaches the liquid crystal display panel 20 can also contribute to the display.

  Further, the configuration of the liquid crystal display device 100 of the present invention illuminates the liquid crystal display panel 20 by reflecting external light by the reflection sheet 14, but is not limited thereto. Instead, the liquid crystal display device 100 is a transflective or completely reflective liquid crystal display device in which a reflection region is provided for each sub-pixel, and the liquid crystal display panel 20 is illuminated by reflecting external light in the reflection region. Needless to say, the optical effect of the liquid crystal lens sheets 30 to 30d of the present invention that collects and diffuses external light can be obtained.

  Further, in the liquid crystal lens sheets 30 to 30d of the present invention, nematic liquid crystals that are vertically aligned when a voltage is applied are used. Instead, nematic liquid crystals that are vertically aligned when no voltage is applied. Also good. In this case, the optical effect of the concavo-convex lens cannot be obtained when a voltage is applied, but the optical effect of the concavo-convex lens can be obtained when a non-voltage is applied.

  Furthermore, the configuration of the liquid crystal display device 100 of the present invention is not limited to the configuration in which the above-described liquid crystal lens sheets 30 to 30d are disposed on the outer surface of the upper substrate 2 of the liquid crystal display panel 20. Instead, the liquid crystal lens sheet is used. 30-30d can also be set as the structure arrange | positioned between the liquid crystal display panel 20 and the illuminating device 10. FIG. Thus, even if the liquid crystal lens sheets 30 to 30d are arranged between the liquid crystal display panel 20 and the lighting device 10, the optical effect of changing the viewing angle as described above can be obtained.

[Electronics]
Next, specific examples of electronic devices to which the liquid crystal display device 100 according to the present invention can be applied will be described with reference to FIG.

  First, an example in which the liquid crystal display device 100 according to the present invention is applied to a display unit of a portable personal computer (so-called notebook personal computer) will be described. FIG. 16A is a perspective view showing the configuration of this personal computer. As shown in the figure, a personal computer 710 includes a main body 712 having a keyboard 711 and a display 713 to which the liquid crystal display device 100 according to the present invention is applied.

  Next, an example in which the liquid crystal display device 100 according to the present invention is applied to a display unit of a mobile phone will be described. FIG. 16B is a perspective view showing the configuration of this mobile phone. As shown in the figure, the cellular phone 720 includes a plurality of operation buttons 721, a reception port 722, a transmission port 723, and a display unit 724 to which the liquid crystal display device 100 according to the present invention is applied.

  Electronic devices to which the liquid crystal display device 100 according to the present invention can be applied include a liquid crystal television and a viewfinder in addition to the personal computer shown in FIG. 16A and the mobile phone shown in FIG. Type / monitor direct-view type video tape recorder, car navigation device, pager, electronic notebook, calculator, word processor, workstation, videophone, POS terminal, digital still camera, etc.

1 is a side view illustrating a configuration of an electro-optical device according to the invention. It is a top view of the liquid-crystal lens sheet which concerns on 1st Embodiment. It is sectional drawing of the liquid-crystal lens sheet which concerns on 1st Embodiment. It is an expanded sectional view of the liquid crystal lens sheet concerning a 1st embodiment. It is an expanded sectional view of the liquid crystal lens sheet concerning a 1st embodiment. It is a figure which shows the modification of the liquid crystal lens sheet which concerns on 1st Embodiment. It is a figure which shows the modification of the liquid crystal lens sheet which concerns on 1st Embodiment. It is a top view of the liquid-crystal lens sheet which concerns on 2nd Embodiment. It is sectional drawing of the liquid-crystal lens sheet which concerns on 2nd Embodiment. It is an expanded sectional view of the liquid-crystal lens sheet which concerns on 2nd Embodiment. It is sectional drawing of the liquid-crystal lens sheet which concerns on 2nd Embodiment. It is an expanded sectional view of the liquid-crystal lens sheet which concerns on 2nd Embodiment. It is sectional drawing of the liquid-crystal lens sheet which concerns on the 1st modification of 2nd Embodiment. It is sectional drawing of the liquid-crystal lens sheet which concerns on the 1st modification of 2nd Embodiment. It is sectional drawing of the liquid-crystal lens sheet which concerns on the 2nd modification of 2nd Embodiment. It is a figure which shows the example of the electronic device to which the liquid crystal display device of this embodiment is applied.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 Light guide plate, 12 Prism sheet, 13 Diffusion sheet, 14 Reflection sheet, 15 Light source part, 16 LED, 20 Liquid crystal display panel, 30, Liquid crystal lens sheet, 100 Liquid crystal display device

Claims (12)

A display panel;
A liquid crystal lens that is disposed on the viewing side of the display panel and includes a pair of substrates and a liquid crystal layer that is sandwiched between the pair of substrates and includes a nematic liquid crystal that changes an alignment state when a voltage is applied. An electro-optical device. A display panel;
An illumination device that illuminates the display panel by transmitting light;
A liquid crystal lens disposed on the display panel side of the lighting device, and having a pair of substrates, and a liquid crystal layer that is sandwiched between the pair of substrates and made of a nematic liquid crystal that changes an alignment state when a voltage is applied. An electro-optical device comprising:   3. The electro-optical device according to claim 1, wherein the liquid crystal lens includes a plurality of control electrodes formed in stripes on an inner surface of at least one of the pair of substrates.   Among the plurality of control electrodes arranged on one subpixel, the closer to the electrode arranged at a position closer to the center of the subpixel, the higher the applied voltage is set, and the positions closer to both ends of the subpixel. The electro-optical device according to claim 3, wherein the applied voltage is set to be lower as the number of the electrodes arranged on the electrode becomes smaller.   Of the plurality of control electrodes arranged on one subpixel, the applied voltage is set lower as the electrode is arranged closer to the center of the subpixel, and the positions closer to both ends of the subpixel. The electro-optical device according to claim 3, wherein the applied voltage is set higher as the number of the electrodes arranged in the electrode increases.   Among the plurality of control electrodes arranged on one subpixel, the width of the control electrode is increased as the electrode is arranged closer to the center of the subpixel, and the electrodes are arranged closer to both ends of the subpixel. The electro-optical device according to claim 3, wherein the width of the electrode is reduced as the formed electrode is formed.   Of the plurality of control electrodes arranged on one subpixel, the electrode is arranged closer to the center of the subpixel, so that the width thereof is formed to be smaller and arranged closer to both ends of the subpixel. The electro-optical device according to claim 3, wherein the width of the electrode is increased as the formed electrode is formed. The liquid crystal lens has a base layer formed on at least one of the pair of substrates on the liquid crystal layer side of one substrate or the liquid crystal layer side of the other substrate, and on the liquid crystal layer side of the base layer, Each sub-pixel unit is formed with a concave curved surface,
A voltage is applied to the liquid crystal layer by a control electrode formed on the liquid crystal layer side of the one substrate and a control electrode formed on the liquid crystal layer side of the other substrate. The electro-optical device according to claim 1. The liquid crystal lens has a base layer formed on at least one of the pair of substrates on the liquid crystal layer side of one substrate or the liquid crystal layer side of the other substrate, and on the liquid crystal layer side of the base layer, Each sub-pixel unit is formed with a convex curved surface,
A voltage is applied to the liquid crystal layer by a control electrode formed on the liquid crystal layer side of the one substrate and a control electrode formed on the liquid crystal layer side of the other substrate. The electro-optical device according to claim 1. In the liquid crystal lens, a first base layer is formed on the liquid crystal layer side of one of the pair of substrates, a second base layer is formed on the liquid crystal layer side of the other substrate, and the first base layer is formed. On the liquid crystal layer side of the first underlayer and the liquid crystal layer side of the second underlayer, concave curved surfaces are formed in units of one subpixel,
A voltage is applied to the liquid crystal layer by a control electrode formed on the liquid crystal layer side of the one substrate and a control electrode formed on the liquid crystal layer side of the other substrate. The electro-optical device according to claim 1. In the liquid crystal lens, a first base layer is formed on the liquid crystal layer side of one of the pair of substrates, a second base layer is formed on the liquid crystal layer side of the other substrate, and the first base layer is formed. A convex curved surface is formed on each subpixel unit on the liquid crystal layer side of the first underlayer and on the liquid crystal layer side of the second underlayer,
A voltage is applied to the liquid crystal layer by a control electrode formed on the liquid crystal layer side of the one substrate and a control electrode formed on the liquid crystal layer side of the other substrate. The electro-optical device according to claim 1.   An electronic apparatus comprising the electro-optical device according to claim 1 in a display unit.

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