JP2017219618A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device excellent in viewing angle characteristics.SOLUTION: The liquid crystal display device of the present invention includes a liquid crystal panel, an illumination device and a light control member. The illumination device includes a plurality of light-emitting elements and a plurality of condensing members disposed at positions corresponding to the respective light-emitting elements between the plurality of light-emitting elements and the liquid crystal panel, for condensing emission light from the light-emitting element to allow the light to enter the liquid crystal panel. The condensing member is in a frustum shape having a light-entering end face, a light-exiting end face having a larger area than the area of the light-entering end face, and an inclined face in contact with the light-entering end face and with the light-exiting end face, and condenses the emission light from the light-emitting element at least onto a screen horizontal direction of the liquid crystal panel.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a liquid crystal display device.

  A liquid crystal display device is widely used as a display of a portable electronic device such as a mobile phone or a television or a personal computer. Generally, a liquid crystal display device exhibits excellent display characteristics when a display screen is viewed from the front. On the other hand, when the display screen is viewed from an oblique direction, the contrast is lowered and the visibility is likely to deteriorate. Alternatively, there is a case where gradation inversion in which the brightness is reversed in gradation display occurs. For this reason, various methods have been proposed for widening the viewing angle range in which good visibility is obtained and the screen can be observed.

  For example, in Patent Document 1, a liquid crystal panel in an MVA (Multi-domain Vertical Alignment) mode and light emitted from the liquid crystal panel are diffused in the azimuth and polar directions of the liquid crystal panel to control the light emission direction. A liquid crystal display device including a light control member is disclosed.

JP 2014-119651 A

  For example, in a home display, good viewing angle characteristics are required within a predetermined polar angle range in the horizontal direction from the front of the screen. However, as described in Patent Document 1, there is a limit to improvement in viewing angle characteristics by simply combining an MVA mode liquid crystal panel and a light control member. In particular, there is a problem that it is difficult to improve the viewing angle characteristics in a desired polar angle range in the horizontal direction of the screen.

  One embodiment of the present invention has been made to solve the above problems, and an object thereof is to provide a liquid crystal display device having excellent viewing angle characteristics.

  In order to achieve the above object, a liquid crystal display device according to one aspect of the present invention includes a first substrate having a first vertical alignment film, a second substrate having a second vertical alignment film, A liquid crystal layer having negative dielectric anisotropy sandwiched between a first vertical alignment film and the second vertical alignment film; a first polarizing plate disposed on a light incident side of the liquid crystal layer; A liquid crystal panel including a second polarizing plate disposed on the light emission side of the liquid crystal layer, and an illumination device disposed on the light incident side of the liquid crystal panel and emitting light toward the liquid crystal panel, A light control member that is disposed on the light emission side of the liquid crystal panel and controls the light distribution by diffusing the light emitted from the liquid crystal panel in the azimuth and polar directions as viewed from the normal direction of the liquid crystal panel The lighting device includes the liquid crystal panel as viewed from the normal direction of the liquid crystal panel. A plurality of light emitting elements that emit light toward the liquid crystal panel, and a position corresponding to each of the plurality of light emitting elements between the plurality of light emitting elements and the liquid crystal panel. A plurality of condensing members that condense light emitted from the light emitting elements and enter the liquid crystal panel, and the condensing member has a frustum shape, a light incident end surface, A light emitting end face having an area larger than an area of the light incident end face, and an inclined surface in contact with the light incident end face and the light emitting end face, and at least the light emitted from the light emitting element of the liquid crystal panel Concentrate in the horizontal direction of the screen.

  In the liquid crystal display device according to one aspect of the present invention, the light collecting member may be made of a light transmissive material.

In the liquid crystal display device according to one aspect of the present invention, the shape of the light incident end surface is a circle and the shape of the light emitting end surface is an ellipse in a plan view as viewed from the optical axis direction of the light collecting member. When the radius of the circle is r _a , the radius of the ellipse in the horizontal direction of the screen is r _x , and the radius of the ellipse in the vertical direction of the screen is r _y , r _a <r _y <r _x is satisfied. Also good.

In the liquid crystal display device of one embodiment of the present invention, in a plan view seen from the direction of the optical axis of the light emitting element, a circle shape of the light exit surface of the light emitting element to a maximum radius and r _b, r _b < _Ra may be satisfied.

  In the liquid crystal display device according to one aspect of the present invention, the light control member includes a light-transmitting base material, a light diffusion portion formed on the first surface of the base material, and the first surface of the base material. A light shielding portion formed in a region other than the region where the light diffusing portion is formed, and the light diffusing portion is disposed on a side opposite to the base material side, and a light emitting end surface located on the base material side. A light incident end surface that is positioned and has an area larger than the area of the light exit end surface, and a light reflecting surface located between the light exit end surface and the light incident end surface, and the light diffusion portion Refraction lower than the refractive index of the light diffusing part in the gap between the light diffusing parts in the non-formation region of the light diffusing part is higher than the height of the light shielding part from the light incident end face to the light emitting end face A substance having a rate may be present.

  In the liquid crystal display device according to one aspect of the present invention, the light diffusion characteristics of the light control member may have two or more axes of line symmetry when viewed from the normal direction of the liquid crystal panel.

  In the liquid crystal display device according to one aspect of the present invention, the planar shape of the light shielding portion viewed from the normal direction of the base material is an anisotropic shape having a major axis and a minor axis, The extending direction of the long axis may substantially coincide with the vertical direction of the screen, and the extending direction of the short axis may substantially coincide with the horizontal direction of the screen.

  In the liquid crystal display device according to one aspect of the present invention, the extending direction of the long axis and the extending direction of the short axis of the light shielding portion are the extending direction of the polarization axis of the first polarizing plate and the second direction. The polarizing axis of the polarizing plate may substantially coincide with the extending direction of the polarizing axis.

  In the liquid crystal display device according to one aspect of the present invention, the extending direction of the long axis of the light shielding portion and the extending direction of the long axis of the ellipse may be substantially orthogonal.

  In the liquid crystal display device according to one aspect of the present invention, the light incident end surface of the light collecting member may be a concave surface including a curved surface at least partially.

  In the liquid crystal display device according to one aspect of the present invention, the inclined surface of the light collecting member has a direction in which an inclination angle with respect to the optical axis of the light collecting member increases sequentially from the light incident end surface toward the light emitting end surface. It may have changed.

  In the liquid crystal display device according to one aspect of the present invention, the illuminating device may further include a diffusion plate positioned on a light emission side of the plurality of light collecting members.

  In the liquid crystal display device according to one aspect of the present invention, the plurality of light emitting elements are arranged at substantially equal intervals, and a distance between the adjacent light emitting elements is larger than a distance between the light emitting elements and the diffusion plate. It may be small.

  In the liquid crystal display device according to one aspect of the present invention, when L is a distance between adjacent light emitting elements and D is a distance between the light emitting elements and the diffusion plate, L / D ≦ 0.7. May be satisfied.

  In the liquid crystal display device according to one aspect of the present invention, the diffusion plate has anisotropy in light diffusion characteristics, and a direction in which the diffusion plate has a small diffusivity substantially coincides with a horizontal direction of the screen of the liquid crystal panel. It may be.

  In the liquid crystal display device according to one aspect of the present invention, the absorption axis of the first polarizing plate and the absorption axis of the second polarizing plate are orthogonal to each other, and the liquid crystal panel is a director of liquid crystal molecules in the liquid crystal layer. May include a plurality of pixels having four domains oriented in four directions intersecting the absorption axis of the first polarizing plate and the absorption axis of the second polarizing plate.

  According to one embodiment of the present invention, a liquid crystal display device having excellent viewing angle characteristics can be provided.

It is sectional drawing of the liquid crystal display device of 1st Embodiment. It is sectional drawing of a liquid crystal panel. It is a schematic diagram which shows the electrical structure of one pixel of a liquid crystal display device. It is a schematic diagram of a light control member. It is a top view of the condensing member with which the backlight was equipped. It is sectional drawing of the condensing member which follows the VIII-VIII line of FIG. It is a figure for demonstrating the definition of a polar angle and an azimuth. It is a figure which shows the relationship between the screen of a liquid crystal display device, and an azimuth. It is a figure which shows the viewing angle when it is visually recognized from the distance where an image is settled in an effective visual field in the range of the image distortion satisfaction limit in the home of Japan. It is a schematic diagram which shows the optical path of the transmitted light and reflected light in a light control member. It is a figure which shows the light beam distribution of the emitted light from a backlight. It is a figure which shows the light distribution of the emitted light from a light emitting diode. It is a figure which shows the light distribution of the emitted light from a condensing member. It is a graph which shows the relationship between the polar angle of the emitted light from a light emitting diode and a condensing member, and a luminance ratio. It is a top view of the diffusion plate with which the backlight was equipped. It is sectional drawing in the screen vertical direction of the diffusion plate of the 1st modification. It is sectional drawing in the screen horizontal direction of the diffusion plate of the 1st modification. It is sectional drawing in the screen vertical direction of the diffusion plate of the 2nd modification. It is sectional drawing in the screen horizontal direction of the diffusion plate of the 2nd modification. It is sectional drawing in the screen vertical direction of the diffusion plate of the 3rd modification. It is sectional drawing in the screen horizontal direction of the diffusion plate of the 3rd modification. It is sectional drawing of the condensing member used for the liquid crystal display device of 2nd Embodiment. It is a figure which shows the light distribution of the emitted light from the condensing member of 1st Embodiment. It is a figure which shows the light distribution of the emitted light from the condensing member which changed the shape of the recessed part. It is a graph which shows the relationship between the polar angle of the emitted light from a light emitting diode or a condensing member, and a luminance ratio. It is sectional drawing of the condensing member used for the liquid crystal display device of 3rd Embodiment. It is a graph which shows the relationship between the polar angle of the emitted light from a light emitting diode or a condensing member, and a luminance ratio. It is an external view which shows the thin television which is one application example of the liquid crystal display device of 1st-3rd embodiment. It is an external view which shows the smart phone which is one application example of the liquid crystal display device of 1st-3rd embodiment. It is an external view which shows the notebook computer which is one application example of the liquid crystal display device of 1st-3rd embodiment. It is a figure which shows an example of the color arrangement | positioning of the color filter which comprises a liquid crystal display device. It is a figure which shows the other example of color arrangement | positioning of the color filter which comprises a liquid crystal display device. It is a figure which shows the other example of color arrangement | positioning of the color filter which comprises a liquid crystal display device. It is a figure which shows the other example of color arrangement | positioning of the color filter which comprises a liquid crystal display device. It is a figure which shows the other example of color arrangement | positioning of the color filter which comprises a liquid crystal display device.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
In this embodiment, an example of a liquid crystal display device including a transmissive liquid crystal panel will be described.
In all of the following drawings, in order to make each component easy to see, the scale of the size may be changed depending on the component.

FIG. 1 is a cross-sectional view of the liquid crystal display device of the first embodiment.
As shown in FIG. 1, the liquid crystal display device 1 includes a liquid crystal panel 2, a backlight 8 (illumination device), and a light control member 9. The liquid crystal panel 2 includes a first polarizing plate 3, a first retardation film 4 (retardation plate), a liquid crystal cell 5, a second retardation film 6 (retardation plate), a second polarizing plate 7, It has. In FIG. 1, the liquid crystal cell 5 is schematically illustrated, but the detailed structure thereof will be described later.

  An observer views the display image of the liquid crystal display device 1 through the light control member 9. In the following description, the side on which the light control member 9 is disposed is referred to as the viewing side. The side on which the backlight 8 is disposed is referred to as the back side. In the following description, the X axis is defined as the horizontal direction of the screen of the liquid crystal display device 1. The Y axis is defined as the vertical direction of the screen of the liquid crystal display device 1. The Z axis is defined as the thickness direction of the liquid crystal display device 1.

  The liquid crystal display device 1 modulates the light emitted from the backlight 8 by the liquid crystal panel 2 and displays a predetermined image, characters, or the like by the modulated light. Further, when the light emitted from the liquid crystal panel 2 passes through the light control member 9, the light distribution distribution of the light emitted from the light control member 9 is wider than the light distribution before entering the light control member 9. It becomes. Thereby, the observer can visually recognize the display with a wide viewing angle.

Hereinafter, a specific configuration of the liquid crystal panel 2 will be described.
Here, an active matrix transmissive liquid crystal panel will be described as an example. However, the liquid crystal panel 2 applicable to the present embodiment is not limited to an active matrix transmissive liquid crystal panel. The liquid crystal panel 2 applicable to the present embodiment may be, for example, a transflective (transmission / reflection type) liquid crystal panel. Furthermore, a simple matrix type liquid crystal panel in which each pixel does not include a switching thin film transistor (hereinafter abbreviated as TFT) may be used.

FIG. 2 is a cross-sectional view of the liquid crystal panel 2.
As shown in FIG. 2, the liquid crystal cell 5 includes a TFT substrate 10, a color filter substrate 12, and a liquid crystal layer 11. The TFT substrate 10 functions as a switching element substrate. The color filter substrate 12 is disposed to face the TFT substrate 10. The liquid crystal layer 11 is sandwiched between the TFT substrate 10 and the color filter substrate 12.

  The liquid crystal layer 11 is sealed in a space surrounded by the TFT substrate 10, the color filter substrate 12, and a frame-shaped seal member (not shown) surrounding the peripheral portions of the TFT substrate 10 and the color filter substrate 12. ing. The sealing member bonds the TFT substrate 10 and the color filter substrate 12 at a predetermined interval.

  The liquid crystal panel 2 performs display in, for example, an MVA (Multi-domain Vertical Alignment) mode. A liquid crystal having a negative dielectric anisotropy is used for the liquid crystal layer 11. A spacer 13 is disposed between the TFT substrate 10 and the color filter substrate 12. The spacer 13 is spherical or columnar. The spacer 13 keeps the distance between the TFT substrate 10 and the color filter substrate 12 constant.

  Although not shown, the TFT substrate 10 has a plurality of pixels serving as a basic unit of display arranged in a matrix. A plurality of signal lines are formed on the TFT substrate 10 so as to extend in parallel to each other. A plurality of scanning lines are formed on the TFT substrate 10 so as to extend in parallel to each other. The plurality of scanning lines and the plurality of signal lines are orthogonal to each other. On the TFT substrate 10, a plurality of signal lines and a plurality of scanning lines are formed in a lattice pattern. A rectangular area defined by adjacent signal lines and adjacent scanning lines is one pixel. The signal line is connected to the source electrode 17 of the TFT 19. The scanning line is connected to the gate electrode 16 of the TFT 19.

  A TFT 19 having a semiconductor layer 15, a gate electrode 16, a source electrode 17, a drain electrode 18 and the like is formed on the surface of the transparent substrate 14 constituting the TFT substrate 10 on the liquid crystal layer 11 side. As the transparent substrate 14, for example, a glass substrate can be used.

  A semiconductor layer 15 is formed on the transparent substrate 14. Examples of the material of the semiconductor layer 15 include semiconductors such as CGS (Continuous Grain Silicon), LPS (Low-temperature Poly-Silicon), and α-Si (Amorphous Silicon). Material is used.

  A gate insulating film 20 is formed on the transparent substrate 14 so as to cover the semiconductor layer 15. As a material of the gate insulating film 20, for example, a silicon oxide film, a silicon nitride film, or a laminated film thereof is used.

  A gate electrode 16 is formed on the gate insulating film 20 so as to face the semiconductor layer 15. As the material of the gate electrode 16, for example, a laminated film of W (tungsten) / TaN (tantalum nitride), Mo (molybdenum), Ti (titanium), Al (aluminum), or the like is used.

  A first interlayer insulating film 21 is formed on the gate insulating film 20 so as to cover the gate electrode 16. As a material of the first interlayer insulating film 21, for example, a silicon oxide film, a silicon nitride film, or a laminated film thereof is used.

  A source electrode 17 and a drain electrode 18 are formed on the first interlayer insulating film 21. A contact hole 22 and a contact hole 23 are formed in the first interlayer insulating film 21 and the gate insulating film 20 so as to penetrate the first interlayer insulating film 21 and the gate insulating film 20. The source electrode 17 is connected to the source region of the semiconductor layer 15 through the contact hole 22. The drain electrode 18 is connected to the drain region of the semiconductor layer 15 through the contact hole 23. As a material for the source electrode 17 and the drain electrode 18, the same conductive material as that for the gate electrode 16 is used.

  A second interlayer insulating film 24 is formed on the first interlayer insulating film 21 so as to cover the source electrode 17 and the drain electrode 18. As the material of the second interlayer insulating film 24, the same material as the first interlayer insulating film 21 described above or an organic insulating material is used.

  A pixel electrode 25 is formed on the second interlayer insulating film 24. A contact hole 26 is formed through the second interlayer insulating film 24 in the second interlayer insulating film 24. The pixel electrode 25 is connected to the drain electrode 18 through the contact hole 26. The pixel electrode 25 is connected to the drain region of the semiconductor layer 15 using the drain electrode 18 as a relay electrode. As the material of the pixel electrode 25, for example, a transparent conductive material such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide) is used.

  With this configuration, when a scanning signal is supplied through the scanning line and the TFT 19 is turned on, an image signal supplied to the source electrode 17 through the signal line passes through the semiconductor layer 15 and the drain electrode 18 to the pixel electrode 25. Supplied. The form of the TFT 19 is not limited to the top gate type TFT shown in FIG. 2, but may be a bottom gate type TFT.

  A first vertical alignment film 27 is formed on the entire surface of the second interlayer insulating film 24 so as to cover the pixel electrode 25. The first vertical alignment film 27 has an alignment regulating force for vertically aligning liquid crystal molecules constituting the liquid crystal layer 11. The first vertical alignment film 27 is a so-called vertical alignment film. In the present embodiment, the first vertical alignment film 27 is subjected to an alignment process using an optical alignment technique. That is, in this embodiment, a photo-alignment film is used as the first vertical alignment film 27.

  A black matrix 30, a color filter 31, a planarizing layer 32, a counter electrode 33, and a second vertical alignment film 34 are sequentially formed on the surface of the transparent substrate 29 constituting the color filter substrate 12 on the liquid crystal layer 11 side. .

  The black matrix 30 blocks light transmission in the inter-pixel region. The black matrix 30 is formed of, for example, a metal material such as Cr (chromium) or a Cr / Cr oxide multilayer film, or a photoresist in which carbon particles are dispersed in a photosensitive resin.

  The color filter 31 includes dyes of red (R), green (G), and blue (B) colors. One color filter 31 of R, G, or B is disposed to face one pixel electrode 25 on the TFT substrate 10. Note that the color filter 31 may have a multicolor configuration of three or more colors of R, G, and B.

  The planarization layer 32 is composed of an insulating film that covers the black matrix 30 and the color filter 31. The flattening layer 32 flattens the step formed by the black matrix 30 and the color filter 31 by relaxing.

  A counter electrode 33 is formed on the planarization layer 32. As the material of the counter electrode 33, a transparent conductive material similar to that of the pixel electrode 25 is used.

  A second vertical alignment film 34 is formed on the entire surface of the counter electrode 33. The second vertical alignment film 34 has an alignment regulating force for vertically aligning the liquid crystal molecules constituting the liquid crystal layer 11. The second vertical alignment film 34 is a so-called vertical alignment film. In the present embodiment, the alignment process is performed on the second vertical alignment film 34 using a photo-alignment technique. That is, in this embodiment, a photo-alignment film is used as the second vertical alignment film 34.

Returning to FIG. 1, the backlight 8 includes a plurality of light emitting diodes (LEDs) 35, a reflection sheet 36, a plurality of light collecting members 37, a diffusion plate 38, and an optical sheet group 39. ing. The plurality of LEDs 35 are arranged on the upper surface of the reflection sheet 36 with the light emission surface facing the liquid crystal panel 2 side. The reflection sheet 36 reflects the light emitted from the plurality of LEDs 35 toward the liquid crystal panel 2. Thus, the backlight 8 of this embodiment is a so-called direct type backlight. The optical sheet group 39 includes, for example, two prism sheets, a scattering sheet, and the like. LED35 of this embodiment respond | corresponds to the light emitting element of a claim.
Other components of the backlight 8 will be described in detail later.

  A first polarizing plate 3 is provided between the backlight 8 and the liquid crystal cell 5. The first polarizing plate 3 functions as a polarizer. A second polarizing plate 7 is provided between the liquid crystal cell 5 and the light control member 9. The second polarizing plate 7 functions as an analyzer. The transmission axis of the first polarizing plate 3 and the transmission axis of the second polarizing plate 7 are in a crossed Nicols arrangement.

  Between the 1st polarizing plate 3 and the liquid crystal cell 5, the 1st phase difference film 4 for compensating the phase difference of the light which permeate | transmitted the 1st polarizing plate 3 is provided. Between the 2nd polarizing plate 7 and the liquid crystal cell 5, the 2nd phase difference film 6 for compensating the phase difference of the light which permeate | transmitted the liquid crystal cell 5 is provided.

FIG. 3 is a diagram schematically illustrating an electrical configuration of one pixel of the liquid crystal display device 1.
As shown in FIG. 3, the pixel 50 is connected to the TFT 19 and the auxiliary capacitor 51. The gate electrode of the TFT 19 is connected to the scanning line 52. The source electrode is connected to the signal line 53. The auxiliary capacitor 51 is connected to the auxiliary capacitor line 55. The auxiliary capacitance 51 includes an auxiliary capacitance electrode electrically connected to the pixel electrode 25, an auxiliary capacitance counter electrode electrically connected to the auxiliary capacitance wiring 55, and an insulating layer (not shown) provided therebetween. Is formed by.

  In FIG. 3, the liquid crystal molecules 54 viewed from the normal direction of the liquid crystal panel 2 are illustrated in a conical shape. The apex of the cone means the end of the liquid crystal molecule 54 on the back side (TFT substrate side). The bottom surface of the cone indicates the end of the liquid crystal molecule 54 on the viewing side (color filter substrate 12 side). In the present embodiment, the director of the liquid crystal molecules 54 is defined as a direction from an end on the back side of the liquid crystal molecules 54 toward an end on the viewing side.

  The pixel 50 employs a four-domain VA having four domains 50a, 50b, 50c, and 50d. When a voltage is applied, the liquid crystal molecules 54 included in the first domain 50a, the liquid crystal molecules 54 included in the second domain 50b, the liquid crystal molecules 54 included in the third domain 50c, and the liquid crystal molecules included in the fourth domain 50d. 54, the azimuths are tilted in directions different from each other by 90 °. That is, in the liquid crystal panel 2 of the present embodiment, the four domains 50 a that face the four directions in which the directors of the liquid crystal molecules 54 of the liquid crystal layer 11 intersect the absorption axis of the first polarizing plate 3 and the absorption axis of the second polarizing plate 7. , 50b, 50c, and 50d.

Next, the light control member 9 will be described in detail.
FIG. 4 is a schematic diagram of the light control member 9. In FIG. 4, the lower left side is a plan view of the light control member 9. The lower right side is a cross-sectional view taken along line AA of the plan view of the lower left side. The upper left side is a cross-sectional view taken along line BB in the plan view of the lower left side.

  As shown in FIG. 4, the light control member 9 includes a base material 41, a plurality of light shielding parts 42, a light diffusion part 43, and a plurality of hollow parts 44. The plurality of light shielding portions 42 are formed on the first surface 41 a (surface opposite to the viewing side) of the base material 41. The light diffusion portion 43 is formed in a region other than the formation region of the light shielding portion 42 on the first surface 41 a of the base material 41.

  As shown in FIG. 1, the light control member 9 is disposed on the second polarizing plate 7 with the light diffusion portion 43 facing the second polarizing plate 7 and the base material 41 facing the viewing side. The light control member 9 is fixed to the second polarizing plate 7 through the adhesive layer 45.

  For the base material 41, for example, triacetylcellulose (TAC) film, polyethylene terephthalate (PET), polycarbonate (PC), polyethylene naphthalate (PEN), polyethersulfone (PES) film, etc., a transparent resin having optical transparency A base material made of is preferably used.

  In the manufacturing process, the base material 41 becomes a base when the material for the light shielding part 42 and the light diffusion part 43 is applied later. The base material 41 needs to have heat resistance and mechanical strength in a heat treatment step during the manufacturing process. Therefore, as the base material 41, a glass base material or the like may be used in addition to the resin base material. However, it is preferable that the thickness of the base material 41 be as thin as possible without impairing heat resistance and mechanical strength. The reason is that as the thickness of the base material 41 becomes thicker, there is a possibility that display blur may occur. Further, the total light transmittance of the base material 41 is preferably 90% or more as defined in JIS K7361-1. When the total light transmittance is 90% or more, sufficient transparency can be obtained. In the present embodiment, a transparent resin substrate having a thickness of 100 μm is used as an example.

  As shown in FIG. 4, the light shielding portions 42 are randomly arranged as viewed from the normal direction of the first surface 41 a of the base material 41. As an example, the light-shielding portion 42 is made of an organic material having light absorption and photosensitivity such as black resist and black ink. In addition, it may be composed of a metal film such as Cr (chromium) or a Cr / Cr oxide multilayer film.

  The light diffusing portion 43 is made of an organic material having optical transparency and photosensitivity such as acrylic resin and epoxy resin. Moreover, it is preferable that the total light transmittance of the light-diffusion part 43 is 90% or more by prescription | regulation of JISK7361-1. When the total light transmittance is 90% or more, sufficient transparency can be obtained.

  The light diffusion portion 43 has a light emission end face 43a, a light incident end face 43b, and a reflection face 43c. The light emission end surface 43a is a surface in contact with the base material 41 and is a surface from which light is emitted. The light incident end surface 43b is a surface facing the light emitting end surface 43a, and is a surface on which light is incident. The reflection surface 43 c is a tapered side surface of the light diffusion portion 43, and is a surface on which light traveling inside the light diffusion portion 43 is reflected. The area of the light incident end face 43b is larger than the area of the light exit end face 43a.

  The light diffusion portion 43 is a portion that contributes to light transmission in the light control member 9. Of the light incident on the light diffusing portion 43, the light L1 is emitted from the light emitting end face 43a without being reflected by the reflecting surface 43c. Of the light incident on the light diffusing portion 43, the light L2 is totally reflected by the reflecting surface 43c of the light diffusing portion 43, proceeds in a state of being substantially confined inside the light diffusing portion 43, and is emitted from the light emitting end surface 43a. Is done.

  The inclination angle θc of the reflection surface 43c of the light diffusion portion 43 (angle formed by the light incident end surface 43b and the reflection surface 43c) is about 85 ° as an example. However, the inclination angle θc of the reflection surface 43c of the light diffusing portion 43 is not particularly limited as long as the angle can sufficiently diffuse the light L2 when the light L2 is emitted from the light control member 9. In the present embodiment, the inclination angle θc of the reflection surface 43c of the light diffusing portion 43 is constant at all locations on the reflection surface 43c.

  The height from the light incident end face 43 b to the light exit end face 43 a of the light diffusing part 43 is set to be larger than the thickness of the light shielding part 42. In the case of this embodiment, the thickness of the light-shielding part 42 is about 150 nm as an example. The height from the light incident end surface 43b of the light diffusion portion 43 to the light emitting end surface 43a is, for example, about 20 μm.

  The space between the light diffusion portions 43 in the non-formation region of the light diffusion portion 43, that is, the space surrounded by the reflection surface 43 c and the light shielding portion 42 of the light diffusion portion 43 is a hollow portion 44. A substance having a refractive index lower than the refractive index of the light diffusion portion 43 exists in the hollow portion 44. In the present embodiment, air is present in the hollow portion 44 as a substance having a refractive index lower than that of the light diffusion portion 43.

  Further, it is desirable that the refractive index of the base material 41 and the refractive index of the light diffusion portion 43 are substantially equal. The reason is as follows. For example, consider a case where the refractive index of the base material 41 and the refractive index of the light diffusion portion 43 are significantly different. In this case, when light incident from the light incident end face 43 b is emitted from the light diffusion portion 43, unnecessary light refraction or reflection may occur at the interface between the light diffusion portion 43 and the base material 41. In this case, there is a possibility that problems such as failure to obtain a desired viewing angle and a decrease in the amount of emitted light may occur.

  In the case of the present embodiment, air is interposed in the plurality of hollow portions 44 (outside the light diffusion portion 43). Therefore, if the light diffusion part 43 is formed of, for example, a transparent acrylic resin, the reflection surface 43c of the light diffusion part 43 becomes an interface between the transparent acrylic resin and air. Here, the hollow portion 44 may be filled with another low refractive index material. However, the difference in the refractive index at the interface between the inside and the outside of the light diffusing portion 43 is maximized when air is present rather than when any low refractive index material is present outside. Therefore, according to Snell's law, in the configuration of the present embodiment, the critical angle is the smallest, and the incident angle range in which the light can be totally reflected by the reflecting surface 43c of the light diffusion portion 43 is the widest. As a result, light loss is further suppressed, and high luminance can be obtained.

  As shown in the lower left part of FIG. 4, in the light control member 9 of the present embodiment, a plurality of light blocking portions 42 are provided on one surface of the base material 41. The planar shape of the light-shielding portion 42 viewed from the normal direction of the base material 41 is an anisotropic shape having a major axis and a minor axis, and is an ellipse as an example. As for the ellipse forming the planar shape of each light shielding portion 42, the major axis direction of the ellipse substantially coincides with the vertical direction (Y-axis direction) of the screen, and the minor axis direction of the ellipse is substantially the horizontal direction of the screen (X-axis direction). Is almost the same. Therefore, the extending direction Dy of the long axis and the extending direction Dx of the short axis of the light shielding part 42 are the extending direction P1 of the polarizing axis of the first polarizing plate 3 and the extending direction P2 of the polarizing axis of the second polarizing plate 7. Is almost the same.

  With the above configuration, when the direction of the reflection surface 43c of the light diffusion portion 43 is considered, the ratio of the reflection surface 43c facing in the X-axis direction out of the reflection surface 43c of the light diffusion portion 43 is the reflection surface facing in the Y-axis direction. More than 43c. Therefore, the light Ly reflected by the reflecting surface 43c facing in the X-axis direction and diffused in the Y-axis direction is larger than the light Lx reflected by the reflecting surface 43c facing in the Y-axis direction and diffused in the X-axis direction. .

  In this way, the planar shape of the light-shielding portion 42 is an anisotropic shape such as an ellipse, the long axis direction is made to coincide with the screen vertical direction, and the short axis direction is made to coincide with the horizontal direction of the screen, so Can be increased. Thereby, a big effect can be acquired in the improvement of the chromaticity viewing angle of the screen horizontal direction in the liquid crystal display device 1. FIG.

  As shown in the upper left side and the lower right side of FIG. 4, the space corresponding to the lower part of each light shielding part 42 becomes a truncated cone-shaped hollow part 44. That is, the light control member 9 has a plurality of hollow portions 44. The light diffusing portion 41 is integrally provided in a portion other than the plurality of hollow portions 42. According to this configuration, the mechanical strength of the light control member 9 can be increased.

  The planar shape of the light shielding unit 42 may include a polygonal shape, a semicircular shape, or the like in addition to the elliptical shape. The planar shape of the light shielding part 42 is preferably a shape having two or more axes of line symmetry. The shape having line symmetry of two or more axes refers to a shape that is line symmetric with respect to at least two or more line segments.

  For example, a rectangle is mentioned as a shape symmetrical with respect to two line segments. In the case of the present embodiment, a rectangular light-shielding portion whose long side direction substantially matches the vertical direction of the screen (Y-axis direction) and whose short side direction substantially matches the horizontal direction of the screen (X-axis direction) is used. It is preferred that In addition to a rectangle, a stripe-shaped light shielding portion that extends long in the vertical direction (Y-axis direction) of the screen may be used. Thus, when the planar shape of the light-shielding portion 42 has a shape having line symmetry of two or more axes, the light scattering characteristics of the light control member 9 are two or more axes when viewed from the normal direction of the liquid crystal panel 2. It has symmetry. Moreover, a part of light shielding part 40 may overlap and be formed.

Hereinafter, the light collecting member 37 provided in the backlight 8 will be described.
As shown in FIG. 1, each of the plurality of light collecting members 37 is provided at a position corresponding to each of the plurality of LEDs 35 in a space between the plurality of LEDs 35 and the liquid crystal panel 2. The condensing member 37 condenses the light emitted from the LED 35 and causes the light to enter the liquid crystal panel 2. When viewed from the normal direction of the liquid crystal panel 2, the plurality of LEDs 35 are arranged in a grid at predetermined intervals. The interval between two adjacent LEDs 35 is substantially equal. Further, the interval between two LEDs 35 adjacent in the horizontal direction of the screen and the interval between two LEDs 35 adjacent in the vertical direction of the screen may be equal or different.

FIG. 5 is a plan view of the light collecting member 37. 6 is a cross-sectional view of the light collecting member 37 taken along the line VIII-VIII in FIG.
As shown in FIGS. 5 and 6, the light collecting member 37 has a frustum shape, and has a light incident end surface 37 a, a light exit end surface 37 b, and an inclined surface 37 c. The light incident end surface 37 a is a flat surface facing the LED 35. The light emission end face 37b is located on the opposite side to the LED 35 and is a face parallel to the light incident end face 37a. The light emission end face 37b has an area larger than the area of the light incident end face 37a. The inclined surface 37c is in contact with the light incident end surface 37a and the light emitting end surface 37b, and is inclined with respect to the light incident end surface 37a and the light emitting end surface 37b.

  Although not shown in FIGS. 1 and 6, the light incident end surface 37 a of the light collecting member 37 is provided with a leg portion that protrudes downward from the light incident end surface 37 a. The condensing member 37 is supported on the reflection sheet 36 by the legs so that the light incident end surface 37 a of the condensing member 37 is positioned at a predetermined interval from the LED 35. However, the support structure of the light collecting member 37 is not limited to the above-described form. For example, the light collecting member 37 may be supported using a support member separate from the light collecting member 37.

  The condensing member 37 is made of a light transmissive material. The material of the light collecting member 37 preferably has heat resistance in addition to light transmittance, and for example, a material such as polymethyl methacrylate (PMMA) is used. The light L3 incident from the light incident end surface 37a is totally reflected by the inclined surface 37c while traveling inside the light collecting member 37, and is emitted from the light emitting end surface 37b while changing the traveling direction. The condensing member 37 condenses the light L3 emitted from the LED 35 at least in the horizontal direction of the screen of the liquid crystal panel 2.

  As shown in FIG. 5, the light incident end surface 37 a of the light collecting member 37 is a circle (perfect circle) in a plan view as viewed from the optical axis C direction of the light collecting member 37. The shape of the end surface 37b is an ellipse. The condensing member 37 has a long axis direction of the ellipse, which is a planar shape of the light exit end surface 37b, oriented in the horizontal direction of the screen (X-axis direction), and a short axis direction of the ellipse is oriented in the vertical direction of the screen (Y-axis direction). Has been placed. Therefore, the major axis direction of the light emission end surface 37 b of the light collecting member 37 is substantially orthogonal to the major axis direction of the light shielding portion 42 of the light control member 9. The minor axis direction of the light exit end surface 37 b of the light collecting member 37 is substantially orthogonal to the minor axis direction of the light shielding portion 42 of the light control member 9.

  In the plan view of the light collecting member 37 viewed from the direction of the optical axis C, the shape of the light exit surface 35a of the LED 35 is a circle (perfect circle). Further, the position of the center of the circle which is the planar shape of the light incident end surface 37a of the light collecting member 37, the center of the ellipse which is the planar shape of the light emitting end surface 37b, and the center of the circle which is the planar shape of the light emitting surface 35a of the LED 35. Are all in agreement.

The radius of the circle that is the planar shape of the light incident end surface 37a of the light collecting member 37 is represented by r _a , and the radius in the major axis direction (horizontal direction of the screen) of the ellipse that is the planar shape of the light emitting end surface 37b of the light collecting member 37 is represented by r _x. When the radius in the minor axis direction (vertical direction of the screen) of the ellipse is r _y , r _a <r _y <r _x is satisfied. That is, the major axis radius _{r x} and a minor axis radius _{r y} of the light-emitting end face 37b of the condensing member 37 is greater than the radius _{r a} of the light incident end face 37a of condensing member 37. Thereby, the inclined surface 37c of the condensing member 37 exhibits a reverse taper shape from the lower side (side in contact with the reflection sheet 36) to the upper side (side away from the reflection sheet 36).

When LED35 of the radius of the circle is a plan shape of the light exit plane 35a was _{r b,} satisfies _r b <r _a. That is, the radius of the light incident end surface 37 a of the light collecting member 37 is larger than the radius of the light emitting surface 35 a of the LED 35. Accordingly, a large amount of light emitted from the LED 35 can be incident on the light collecting member 37, and the light utilization efficiency can be increased. Further, the height (dimension in the Z-axis direction) of the light condensing member 37 is not particularly limited because it is appropriately set depending on the LED 35, the optical sheet group 39, the required degree of light condensing, and the like.

Here, a polar angle and an azimuth angle of the liquid crystal display device 1 used in the following description will be described.
FIG. 7 is a diagram for explaining the definition of the polar angle and the azimuth angle.
As shown in FIG. 7, the angle formed by the observer's line-of-sight direction F with respect to the normal direction E of the screen of the liquid crystal display device 1 is defined as a polar angle θ. Further, the angle formed by the extending direction of the line segment G when the viewer's line-of-sight direction F is projected onto the screen with respect to the positive direction of the X-axis, with the positive direction of the X-axis being the reference (0 °). Defined as φ.

FIG. 8 is a diagram showing the relationship between the screen of the liquid crystal display device 1 and the azimuth angle.
As shown in FIG. 8, on the screen of the liquid crystal display device 1, the horizontal direction (the positive direction and the negative direction of the X axis) is the azimuth angle φ: 0 ° -180 ° direction. A vertical direction (a positive direction and a negative direction in the Y-axis direction) is defined as an azimuth angle φ: 90 ° -270 ° direction. In the present embodiment, the transmission axis of the first polarizing plate 3 is set in the azimuth angle φ: 90 ° -270 ° direction, and the transmission axis of the second polarizing plate 7 is in the azimuth angle φ: 0 ° -180 ° direction. Is set.

Next, the viewing angle range required for the liquid crystal display device 1 in the vertical and horizontal directions will be described.
Since the human eye is horizontally long and horizontally arranged side by side, the left and right visual fields are wide, and the upper and lower visual fields are narrow. For example, JEITA's “Ergonomics Symposium on Flat Panel Display 2003” document “The Pros and Cons of Guidelines Standardization for the Development of Ergonomic Guidelines for TV Viewing (Japan Ergonomics Society, Yuzo Hisatake)” Main research results and ISO standard requirements are shown.

FIG. 9 shows the viewing angle viewed from the normal direction of the screen. A range surrounded by a broken line indicates a satisfaction limit of image distortion in a general Japanese home. A range surrounded by a one-dot chain line indicates a viewing angle when the image is observed from a distance within an effective visual field within a range of image distortion satisfaction.
As shown in FIG. 9, the viewing angle in the horizontal direction of a human is about 42 °. The viewing angle in the lower position is 35 °, while the viewing angle in the upper direction is slightly smaller than 20 °. Therefore, when the liquid crystal display device is used as a home television, the viewing angle characteristics below the upper side are important. Furthermore, from the viewpoint that image distortion can be satisfied, the minimum viewing angle range is 33 ° in the horizontal direction of the screen.

FIG. 10 is a schematic diagram showing a result of a simulation of the optical paths of the transmitted light L1 and the reflected light L2 in the light control member 9.
As shown in FIG. 10, when the transmitted light L1 is assumed, the light L1 incident at an incident angle θin = 33 ° with respect to the light incident end surface 43a of the light diffusing portion 43 is not reflected by the side surface 43c, but is emitted from the light emitting end surface. After passing through 43b, the light is emitted from the upper surface of the base material 41 at an emission angle θout = 33 °. On the other hand, assuming the reflected light L2, the light L2 incident at an incident angle θin = 17 ° with respect to the light incident end surface 43a of the light diffusing portion 43 is reflected by the side surface 43c and then emerges from the upper surface of the base material 41 from the upper surface 41 = 33 ° injection. In this simulation, the taper angle (angle formed between the light incident end face 43a and the side face 43c) of the light diffusion portion 43 was set to 85 °, and the refractive index of the light diffusion portion 43 was set to 1.6. The base material 41 is a parallel plate, and light is offset by being refracted when it is emitted from the base material 41 by the amount of the refraction angle when entering the base material 41, and the traveling direction is not changed. Therefore, the refractive index of the base material 41 is not questioned.

  Considering the simulation result of FIG. 10, among the light emitted from the liquid crystal panel 2, the more the light incident on the light diffusion portion 43 of the light control member 9 at an incident angle of 33 °, the lower the viewing angle characteristic. That is, the light incident on the light control member 9 at a relatively small incident angle is light that has been transmitted through the liquid crystal panel 2 at an angle close to the normal direction, and thus has excellent viewing angle characteristics. On the other hand, the light incident on the light control member 9 at a relatively large incident angle such as an incident angle of 33 ° is light that has been transmitted through the liquid crystal panel 2 at an angle inclined from the normal direction. Inferior in characteristics. Accordingly, when the light emitted from the light control member 9 is viewed as a whole, the viewing angle characteristic decreases as the amount of light incident on the light control member 9 with a relatively large incident angle increases.

FIG. 11 is a diagram showing a light flux distribution of light emitted from the backlight 8. The horizontal axis in FIG. 11 is the polar angle [°], and the vertical axis is the luminous flux [relative value].
Based on the above knowledge, the present inventors collect a part of the light emitted from the backlight 8 toward the wide angle side in the horizontal direction to the narrow angle side to increase the front luminance. It was thought that the viewing angle characteristics could be improved. Specifically, as shown in FIG. 11, the present inventors reduced the light emitted near a polar angle of 33 ° and emitted it near a polar angle of 17 ° with respect to the conventional light flux distribution indicated by a broken line. By increasing the amount of light, it was considered that the light transmitted through the liquid crystal panel 2 at an angle close to the normal direction can be diffused by the light control member 9 and the viewing angle characteristics can be improved.

Therefore, the present inventors performed a simulation of the light collecting effect by the light collecting member 37 used in the backlight 8. Hereinafter, the results of the simulation will be described.
FIG. 12 is a diagram showing a light distribution of light emitted from the LED 35. FIG. 13 is a diagram illustrating a light distribution of light emitted from the light collecting member 37.

  As shown in FIG. 12, the light L0 emitted from the LED 35 has a wide Lambertian distribution of light from a polar angle of about 0 ° to about 60 °. On the other hand, as shown in FIG. 13, the light LS emitted from the LED 35 passes through the light collecting member 37. Of the light L0 emitted from the LED 35, the light incident on the light collecting member 37 at a relatively large incident angle is reflected by the inclined surface 37c, and the traveling direction of the light is close to the normal direction of the light incident end surface 37a. Change to the side. Thus, by providing the condensing member 37 on the light emitting side of the LED 35, the light emitted from the LED 35 in the wide angle direction can be condensed in the narrow angle direction.

FIG. 14 is a graph showing the relationship between the polar angle of the light emitted from the LED 35 and the light collecting member 37 and the luminance ratio.
In FIG. 14, the horizontal axis represents the polar angle [°], and the vertical axis represents the luminance ratio [−]. The luminance ratio is a luminance ratio when the luminance of light emitted from the LED 35 in the polar angle 0 ° direction is 1.
A broken line graph A shows a luminance ratio distribution of light emitted from the LED 35. A solid line graph B shows the luminance ratio distribution of the emitted light from the light collecting member 37 along the horizontal direction of the screen (azimuth angle 0 ° -180 ° direction). A dashed-dotted line graph C shows the luminance ratio distribution of the light emitted from the light collecting member 37 along the vertical direction of the screen (azimuth angle 90 ° -270 ° direction).

  As shown in FIG. 14, the light emitted from the light condensing member 37 has a greatly reduced luminance ratio in the vicinity of a polar angle of 33 °, compared to the light emitted from the LED 35 in both the horizontal and vertical directions of the screen. ing. Therefore, it was found that the light emitted from the LED 35 is condensed in the polar angle 0 ° direction (front direction) by passing through the light collecting member 37.

  As described above, according to the liquid crystal display device 1 of the present embodiment, the condensing member 37 is provided corresponding to each of the plurality of LEDs 35 of the backlight 8, so that each LED 35 emits light in the wide-angle direction. The collected light is collected in a narrow angle direction (front direction) by the light collecting member 37. Therefore, when the light emitted from the backlight 8 passes through the liquid crystal panel 2 and enters the light control member 9, the proportion of light with poor viewing angle characteristics is reduced, and the viewing angle characteristics can be improved as a whole. . Thereby, the liquid crystal display device 1 with little image distortion and excellent color reproducibility and viewing angle characteristics can be realized.

  In the liquid crystal display device 1 of the present embodiment, the direct type backlight 8 is used, and the light emitted from the LED 35 is collected by the light collecting member 37, so that uneven brightness within the screen is likely to occur. , Has the problem of. This problem can be addressed by shortening the distance between the adjacent LEDs 35 or increasing the distance from the LED 35 to the diffusion plate 38.

  As shown in FIG. 1, assuming that the plurality of LEDs 35 are arranged at substantially equal intervals, the distance between adjacent LEDs 35 is R, and the distance between the LED 35 and the diffusion plate 38 is D. In order to solve the above problem, it is preferable that the distance R between the adjacent LEDs 35 is at least smaller than the distance D between the LED 35 and the diffusion plate 38. That is, it is at least desirable that the backlight 8 of the present embodiment satisfies the condition of R / D <1.

Furthermore, the present inventors examined the ratio between the distance between adjacent LEDs 35 and the distance from the LED 35 to the diffusion plate 38.
As the value of R / D, first, R / D = 3.3, which is an example of the current direct type backlight, was examined. When R / D = 3.3, the backlight 8 of the present embodiment includes the light collecting member 37. Therefore, the luminance unevenness due to the backlight 8 of the present embodiment is the current general direct type backlight. It becomes larger than the luminance unevenness.

  Next, various R / D values satisfying the range of R / D <1 were examined. As a result, by setting the value of R / D within the range of R / D ≦ 0.7, the luminance unevenness due to the backlight 8 of the present embodiment is the luminance unevenness of the current general direct type backlight. It was confirmed that it was equivalent or less. Further, by passing the light emitted from the light condensing member 37 through the optical sheet group 39 such as the diffusion plate 38 and the prism sheet, the difference in brightness when entering the liquid crystal panel 2 can be further reduced. That is, it is further desirable that the backlight 8 of the present embodiment satisfies the condition of R / D ≦ 0.7.

Further, the backlight 8 of the present embodiment further includes a diffusion plate 38 positioned on the light exit side of the plurality of light collecting members 37. FIG. 15 is a plan view of the diffusion plate 38.
As shown in FIG. 15, the diffusion plate 38 includes a base material 381 and a plurality of diffusion materials 382 dispersed inside the base material 381. The arrangement density of the plurality of diffusion materials 382 differs between the horizontal direction of the screen and the vertical direction of the screen. Specifically, the arrangement density of the diffusion material 382 in the horizontal direction of the screen is smaller than the arrangement density of the diffusion material 382 in the vertical direction of the screen. Therefore, the diffusion plate 38 has anisotropy in light diffusibility in the horizontal direction and the vertical direction of the screen. The light diffusibility in the horizontal direction of the screen is smaller than the light diffusibility in the vertical direction of the screen. Thereby, the direction in which the light diffusibility in the diffusion plate 38 is large is parallel to the major axis direction of the light shielding portion 42 of the light control member 9.

  In the liquid crystal display device 1 of the present embodiment, the backlight 8 includes the light collecting member 37, so that the light emitted from the backlight 8 is condensed at least in the horizontal direction of the screen. Therefore, as described above, the diffusing plate 38 preferably has a light diffusibility in the horizontal direction of the screen smaller than that in the vertical direction of the screen. Thereby, the brightness unevenness in a screen can be reduced, improving the viewing angle characteristic of the liquid crystal display device 1 effectively.

The diffusion plate used in the liquid crystal display device 1 of the present embodiment only needs to have diffusion anisotropy. As a means for imparting diffusion anisotropy, the arrangement density of a plurality of diffusion materials is set in the horizontal direction of the screen and the screen. It is not restricted to the diffuser plate 38 of FIG. 15 which is different in the vertical direction.
For example, the diffusion plates of the following first to third modifications may be used.

FIG. 16A is a cross-sectional view in the screen vertical direction of the diffusion plate 56 of the first modification. FIG. 16B is a cross-sectional view in the horizontal direction of the screen of the diffusion plate 56 of the first modification.
As shown in FIGS. 16A and 16B, the diffusion plate 56 includes a base material 561 and a plurality of elliptical diffusing materials 562. The plurality of diffusing materials 562 are oriented so that the cross-sectional shape in the screen vertical direction (Y-axis direction) of each diffusing material 562 is circular and the cross-sectional shape in the horizontal screen direction (X-axis direction) is elliptical. .

FIG. 17A is a cross-sectional view of the diffusion plate 57 of the second modified example in the screen vertical direction. FIG. 17B is a cross-sectional view of the diffusion plate 57 of the second modified example in the horizontal direction of the screen.
As illustrated in FIGS. 17A and 17B, the diffusion plate 57 includes a base material 571, a plurality of spherical diffusion materials 572, and a plurality of prism structures 573. The plurality of prism structures 573 are formed so that a prismatic prism structure 573 extends in the horizontal direction of the screen (X-axis direction) and is arranged in the vertical direction of the screen (Y-axis direction).

FIG. 18A is a cross-sectional view of the diffusion plate 58 of the third modified example in the screen vertical direction. FIG. 18B is a cross-sectional view of the diffusion plate 58 of the third modification in the horizontal direction of the screen.
As shown in FIGS. 18A and 18B, the diffusion plate 58 includes a base material 581 and a plurality of convex bodies 582. In the plurality of convex bodies 582, the longitudinal direction of each convex body 582 is substantially coincident with the horizontal direction of the screen (X-axis direction), and the short direction of each convex body 582 is substantially parallel to the screen vertical direction (Y-axis direction). It is formed to match. As this type of diffusion plate 58, for example, a nano buckling sheet manufactured by Oji Paper Co., Ltd. can be used.

[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described with reference to FIGS.
The basic configuration of the liquid crystal display device of the second embodiment is the same as that of the first embodiment, and the configuration of the light collecting member is different from that of the first embodiment. Therefore, in 2nd Embodiment, only a condensing member is demonstrated.
FIG. 19 is a cross-sectional view of a light collecting member used in the liquid crystal display device of the second embodiment.
19 to 22, the same components as those used in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

FIG. 20 is a diagram illustrating a light distribution of emitted light from the light collecting member 37 according to the first embodiment.
As shown in FIG. 20, in the light collecting member 37 of the first embodiment, the light incident end surface 37 a is a flat surface and is a surface parallel to the light emitting surface 35 a of the LED 35. In this case, of the light emitted from the LED 35, a part of the light L5 emitted at a relatively large emission angle is incident on the light incident end surface at a large incident angle. Therefore, the light L <b> 5 is reflected by the light incident end surface 37 a and cannot enter the light collecting member 37. Since the light L5 does not enter the liquid crystal panel 2 and does not contribute to display, it causes a reduction in light use efficiency.

On the other hand, as shown in FIG. 19, the light incident end surface 62a of the light collecting member 62 of the second embodiment is provided with a concave portion 63 whose inner surface is gently curved. Further, when viewed from the direction of the optical axis C of the light collecting member 62, the planar shape of the recess 63 is circular. The center of the circle forming the planar shape of the recess 63 coincides with the center of the circle forming the planar shape of the entire light incident end surface 62a. With this configuration, the entire light incident end face 62a is a curved concave surface.
Other configurations are the same as those of the first embodiment.

  According to the configuration of the present embodiment, the light incident end face 62a is also concave for the light L6 emitted at the same emission angle as the light L5 that cannot contribute to display in the light collecting member 37 of the first embodiment. The incident angle with respect to the light incident end face 62a is smaller than the incident angle with respect to the light incident end face 37a of the first embodiment. As a result, the light L6 enters the condensing member 62 from the light incident end face 62a. Thereby, since the light L6 enters the liquid crystal panel 2 and can contribute to the display, the light use efficiency can be improved as compared with the first embodiment.

  In order to effectively obtain the light collecting effect by the light collecting member 62, when the radius of the circle which is the planar shape of the concave portion 63 is b (mm) and the maximum depth of the concave portion 63 is h (mm), the concave portion The ratio h / b of the maximum depth h to the radius b of 63 is preferably 0 <h / b <1. Specifically, h / b is desirably about 0.5. FIG. 19 shows the light distribution of the emitted light from the light collecting member 62 when h / b = 0.5.

FIG. 21 is a diagram showing a light distribution of emitted light from the light collecting member 65 when the ratio of the maximum depth h to the radius b of the recess 66 is 1 (h / b = 1).
As shown in FIG. 21, even when h / b = 1, light emitted from the LED 35 to the wide angle side is incident on the inside of the light collecting member 65, so that the light use efficiency can be improved. However, in the light collecting member 65 shown in FIG. 21, the amount of light emitted in the direction of diverging in a wide angle is slightly larger than that of the light collecting member 62 having h / b = 0.5 shown in FIG. . Therefore, it is desirable that 0 <h / b <1.

  Also in the present embodiment, the backlight 8 includes the light collecting members 62 and 65, so that a liquid crystal display device with less image distortion and excellent color reproducibility and viewing angle characteristics can be realized. Similar effects can be obtained.

FIG. 22 shows the simulation results of the present inventors and is a graph showing the relationship between the polar angle of the emitted light from the light collecting member 62 of the second embodiment and the luminance ratio.
In FIG. 22, the horizontal axis indicates the polar angle [°], and the vertical axis indicates the luminance ratio [−]. The luminance ratio is a luminance ratio when the luminance of light emitted from the LED 35 in the polar angle 0 ° direction is 1.
A broken line graph A shows a luminance ratio distribution of light emitted from the LED 35. A solid line graph B shows a luminance ratio distribution of light emitted from the light collecting member 62 along the horizontal direction of the screen (azimuth angle 0 ° -180 ° direction). A dashed-dotted line graph C shows the luminance ratio distribution of the light emitted from the light collecting member 62 along the vertical direction of the screen (azimuth angle 90 ° -270 ° direction).

  As shown in FIG. 22, the brightness ratio of the light emitted from the light collecting member 62 is greatly reduced in the vicinity of the polar angle of 33 ° compared to the light emitted from the LED 35 in both the horizontal direction and the vertical direction of the screen. ing. Therefore, it was found that the light emitted from the LED 35 is condensed in the polar angle 0 ° direction (front direction) by passing through the light collecting member 62.

  In the case of the second embodiment, the luminance ratio at a polar angle of 33 ° is reduced to about 0.5 in the vertical direction of the screen, but is reduced to about 0.3 in the horizontal direction of the screen. . In this way, it was found that the condensing effect in the horizontal direction of the screen, which is the azimuth angle direction in which the condensing state is to be improved, is larger than the condensing effect in the vertical direction of the screen and is ideal for improving the viewing angle. . Further, it was found that the graph of the second embodiment shown in FIG. 22 does not have an inflection point like the graph of the first embodiment shown in FIG. 14 and has a gentle shape. Therefore, when the observer looks at the screen while changing the polar angle, there is little sudden change in brightness, and the display quality from the oblique direction can be effectively enhanced.

  In the present embodiment, an example in which the entire light incident end surfaces 62a and 65a of the light collecting members 62 and 65 are curved concave surfaces is shown. Instead of this configuration, for example, the central portion of the light incident end face of the light collecting member is a flat surface, and only a partial region where light emitted from the LED to the wide angle side is incident is a curved concave surface. May be.

[Third Embodiment]
Hereinafter, a third embodiment of the present invention will be described with reference to FIGS.
The basic configuration of the liquid crystal display device of the third embodiment is the same as that of the first embodiment, and the configuration of the light collecting member is different from that of the first embodiment. Therefore, in 3rd Embodiment, only a condensing member is demonstrated.
FIG. 23 is a cross-sectional view of a light collecting member used in the liquid crystal display device of the third embodiment.
23 to 24, the same reference numerals are given to the same components as those used in the first embodiment, and the description thereof will be omitted.

  The inclined surface 37c of the light collecting member 37 of the first embodiment has a constant inclination angle regardless of the position. On the other hand, as shown in FIG. 23, the inclined surface 71c of the condensing member 71 of the third embodiment changes in a direction in which the inclination angle increases sequentially from the light incident end surface 71a to the light emitting end surface 71b. Yes. That is, when viewed in a cross section cut by a plane including the optical axis C of the light collecting member 37, the cross-sectional shape of the inclined surface 71c is a curved shape curved so as to be convex inward.

An angle formed between tangents S1 and S2 passing through one point on the inclined surface 71c and a straight line V parallel to the optical axis C is defined as an inclination angle α of the inclined surface 71c. At this time, the inclination angle α1 of the inclined surface 71c at the corner where the inclined surface 71c contacts the light incident end surface 71a is, for example, 6 °. The inclination angle α2 at the corner where the inclined surface 71c is in contact with the light emitting end surface 71b is, for example, 12 °. Thus, the inclination angle α of the inclined surface 71c increases from 6 ° to 12 ° from the light incident end surface 71a side toward the light emitting end surface 71b side.
Other configurations are the same as those of the first embodiment.

  As described above, the condensing member 71 reduces the light emitted near the polar angle 33 ° out of the light emitted from the LEDs 35 in various directions, and increases the light emitted near the polar angle 17 °. Is desirable. For this purpose, it is effective to control the light distribution of the emitted light by appropriately changing the inclination angle α of the inclined surface 71c as in the present embodiment, instead of making it constant. Specifically, by changing the inclination angle α of the inclined surface 71c within the range of 6 ° to 12 °, the light emitted near the polar angle 33 ° is reduced and the light emitted near the polar angle 17 ° Can be increased.

  Also in this embodiment, since the backlight 8 includes the light collecting member 71, it is possible to realize a liquid crystal display device with less image distortion and excellent color reproducibility and viewing angle characteristics, as in the first embodiment. An effect is obtained.

FIG. 24 shows the simulation results of the present inventors and is a graph showing the relationship between the polar angle of the emitted light from the condensing member 71 of the third embodiment and the luminance ratio.
In FIG. 24, the horizontal axis indicates the polar angle [°], and the vertical axis indicates the luminance ratio [−]. The luminance ratio is a luminance ratio when the luminance of light emitted from the LED 35 in the polar angle 0 ° direction is 1.
A broken line graph A shows a luminance ratio distribution of light emitted from the LED 35. A solid line graph B shows the luminance ratio distribution of the light emitted from the light collecting member 71 along the horizontal direction of the screen (azimuth angle 0 ° -180 ° direction).

  As shown in FIG. 24, the light emitted from the light condensing member 71 has a brightness ratio on the wide-angle side that is significantly lower than the vicinity of the polar angle of 25 ° as compared with the light emitted from the single LED. For example, when looking at the luminance ratio at a polar angle of 33 °, it is greatly reduced from about 0.9 to about 0.3. In addition, the light emitted from the light collecting member 71 has a brightness ratio on the narrower angle side than the polar angle of 25 ° with respect to the light emitted from the single LED. For example, looking at the luminance ratio at a polar angle of 17 °, it rises to a value exceeding 1.2. Thus, according to the condensing member 71 of this embodiment, the view angle characteristic of a liquid crystal display device is expected to be greatly improved.

[Fourth Embodiment]
The liquid crystal display devices of the first to third embodiments described above can be applied to various electronic devices.
Hereinafter, an electronic apparatus provided with the liquid crystal display device 1 of the first to third embodiments will be described with reference to FIGS.

The liquid crystal display device 1 according to the first to third embodiments described above can be applied to, for example, a thin television 250 shown in FIG.
As shown in FIG. 25, the flat-screen television 250 includes a display unit 251, a speaker 252, a cabinet 253, a stand 254, and the like.
As the display unit 251, the liquid crystal display device 1 of the first to third embodiments described above can be suitably applied. By applying the liquid crystal display device 1 of the first to third embodiments described above to the display unit 251 of the thin television 250, it is possible to display an image with excellent viewing angle characteristics.

The liquid crystal display device 1 of the first to third embodiments described above can be applied to, for example, the smartphone 240 shown in FIG.
As shown in FIG. 26, the smartphone 240 includes a voice input unit 241, a voice output unit 242, an operation switch 244, a display unit 245, a touch panel 243, a housing 246, and the like.
As the display unit 245, the liquid crystal display device 1 of the above-described first to third embodiments can be suitably applied. By applying the liquid crystal display device 1 of the first to third embodiments described above to the display unit 245 of the smartphone 240, an image with excellent viewing angle characteristics can be displayed.

The liquid crystal display device 1 of the first to third embodiments described above can be applied to, for example, a notebook computer 270 shown in FIG.
As shown in FIG. 27, the notebook computer 270 includes a display unit 271, a keyboard 272, a touch pad 273, a main switch 274, a camera 275, a recording medium slot 276, a housing 277, and the like.
As the display unit 271, the liquid crystal display device 1 of the first to third embodiments described above can be suitably applied. By applying the liquid crystal display device 1 of the first to third embodiments described above to the display unit 271 of the notebook computer 270, an image having excellent viewing angle characteristics can be displayed.

The technical scope of some aspects of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the aspect of the present invention.
For example, in the above-described embodiment, an example of a solid light collecting member made of a light-transmitting material such as PMMA is given as the light collecting member. A condensing member may be used in which the inner surface of the cylinder is a reflecting surface.

  The light control member in the above embodiment has a configuration in which at least one of an antireflection structure, a polarizing filter layer, an antistatic layer, an antiglare treatment layer, and an antifouling treatment layer is provided on the viewing side of the base material. May be. According to this configuration, it is possible to add a function to reduce external light reflection, a function to prevent the adhesion of dust and dirt, a function to prevent scratches, and the like according to the type of layer provided on the viewing side of the substrate. Further, it is possible to prevent deterioration of viewing angle characteristics with time.

  In particular, as an example of the antireflection structure, a configuration in which an antiglare layer is provided on the viewing side of the base material of the light control member may be used. As the antiglare layer, for example, a dielectric multilayer film that cancels external light using light interference is used.

  As another example of the antireflection structure, a so-called moth-eye structure may be provided on the viewing side of the base material of the light control member. In the present invention, the moth-eye structure includes the following structures and shapes. The moth-eye structure is a concavo-convex shape with a period equal to or less than the wavelength of visible light, and is a shape or structure using the principle of a so-called “Moth-eye” configuration. The period of the unevenness is controlled to be equal to or less than the wavelength of visible light (λ = 380 nm to 780 nm). The two-dimensional size of the convex portions constituting the concavo-convex pattern is 10 nm or more and less than 500 nm. Reflection is suppressed by continuously changing the refractive index for light incident on the base material from the refractive index of the incident medium (air) to the refractive index of the base material along the depth direction of the unevenness.

  Further, the four domains in the liquid crystal display device may have different areas, and the director directions of the liquid crystal molecules may not be completely different from each other by 90 °. The present invention is applied when there are at least two domains in one pixel, and there may be three or more domains. In that case, the major axis direction and minor axis direction of the light shielding layer of the light control member and the major axis direction and minor axis direction of the light emission end face of the light collecting member are arranged in accordance with the azimuth direction in which the viewing angle characteristics are desired to be improved. That's fine.

  Further, in the above embodiment, as shown in FIG. 28A, one pixel PX of the liquid crystal panel 2 is configured by three rectangular subpixels of red (R), green (G), and blue (B). In the example, these three subpixels are arranged in the horizontal direction (arrow H direction) with the long side direction directed in the vertical direction (arrow V direction) of the screen. The arrangement of subpixels is not limited to this example. For example, as shown in FIG. 28B, three subpixels R, G, and B may be arranged in the vertical direction (arrow V direction) with the long side direction directed in the horizontal direction (arrow H direction) of the screen. .

Further, as shown in FIG. 28C, one pixel of the liquid crystal panel 2 is composed of four rectangular sub-pixels of red (R), green (G), blue (B), and yellow (Y), These four subpixels may be arranged in the horizontal direction (arrow H direction) with the long side direction directed in the vertical direction (arrow V direction) of the screen.
Alternatively, as shown in FIG. 28D, four sub-pixels R, G, B, and Y are arranged in the vertical direction (arrow V direction) with the long side direction directed in the horizontal direction (arrow H direction) of the screen. May be.
Or, as shown in FIG. 28E, one pixel of the liquid crystal panel is composed of four square subpixels R, G, B, and Y, and two rows and two columns in the horizontal and vertical directions of the screen. May be arranged.

  In addition, the specific configuration regarding the material, the number, the arrangement, and the like of each constituent member of the liquid crystal display device and the light control member is not limited to the above-described embodiment, and can be appropriately changed. For example, in the above-described embodiment, an example in which a polarizing plate and a retardation plate are arranged outside the liquid crystal panel has been described. Instead of this configuration, a polarizing layer and a retardation layer are provided inside a pair of substrates constituting the liquid crystal panel. It may be formed.

  The present invention can be used for a liquid crystal display device.

  DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display device, 2 ... Liquid crystal panel, 3 ... 1st polarizing plate, 7 ... 2nd polarizing plate, 8 ... Backlight (illuminating device), 9 ... Light control member, 10 ... TFT substrate (1st board | substrate) , 11 ... Liquid crystal layer, 12 ... Color filter substrate (second substrate), 27 ... First vertical alignment film, 34 ... Second vertical alignment film, 35 ... Light emitting element (LED), 37, 62, 65, 71 ... Light collecting member, 37a ... Light incident end surface, 37b ... Light exit end surface, 37c ... Inclined surface, 38, 56, 57, 58 ... Diffuser plate, 41 ... Base material, 42 ... Light shielding part, 43 ... Light diffusion part, 44 ... hollow part, 50 ... pixel, 50a, 50b, 50c, 50d ... domain.

Claims (16)

Sandwiched between the first substrate having the first vertical alignment film, the second substrate having the second vertical alignment film, and the first vertical alignment film and the second vertical alignment film. A liquid crystal layer having negative dielectric anisotropy, a first polarizing plate disposed on the light incident side of the liquid crystal layer, and a second polarizing plate disposed on the light exit side of the liquid crystal layer. LCD panel,
An illumination device that is disposed on the light incident side of the liquid crystal panel and emits light toward the liquid crystal panel;
A light control member that is disposed on the light emission side of the liquid crystal panel and controls the light distribution by diffusing the light emitted from the liquid crystal panel in the azimuth and polar directions as viewed from the normal direction of the liquid crystal panel And comprising
The lighting device includes:
A plurality of light emitting elements that are provided at positions overlapping the liquid crystal panel as viewed from the normal direction of the liquid crystal panel, and emit light toward the liquid crystal panel;
Between the plurality of light emitting elements and the liquid crystal panel, provided at a position corresponding to each of the plurality of light emitting elements, a plurality of light collectors for condensing the light emitted from the light emitting elements and entering the liquid crystal panel. An optical member,
The condensing member has a truncated cone shape, a light incident end surface, a light emitting end surface having an area larger than an area of the light incident end surface, and an inclined surface in contact with the light incident end surface and the light emitting end surface And condensing light emitted from the light emitting element at least in the horizontal direction of the screen of the liquid crystal panel.   The liquid crystal display device according to claim 1, wherein the light collecting member is made of a light-transmitting material. In a plan view seen from the optical axis direction of the light collecting member, the shape of the light incident end face is a circle, and the shape of the light exit end face is an ellipse,
The radius of the circle is r _a , the radius of the ellipse in the horizontal direction of the screen is r _x , and the radius of the ellipse in the vertical direction of the screen is r _y , wherein r _a <r _y <r _x is satisfied. A liquid crystal display device according to 1. In a plan view seen from the direction of the optical axis of the light emitting element, a circle shape of the light exit surface of the light emitting element to a maximum radius and r _b, satisfy r b _{<r a,} the liquid crystal according to claim 3 Display device. The light control member includes a light-transmitting base material, a light diffusion portion formed on the first surface of the base material, and a region other than a region where the light diffusion portion is formed on the first surface of the base material. A light shielding portion formed in the region,
The light diffusing unit includes a light emitting end face located on the base material side, a light incident end face located on the opposite side of the base material side and having an area larger than the area of the light emitting end face, and the light emitting end face And a light reflecting surface located between the light incident end surface and
The height from the light incident end face of the light diffusion part to the light emission end face is higher than the height of the light shielding part,
The liquid crystal display device according to claim 1, wherein a substance having a refractive index lower than a refractive index of the light diffusing portion is present in a gap between the light diffusing portions in a non-formation region of the light diffusing portion.   The liquid crystal display device according to claim 5, wherein the light diffusion characteristic of the light control member has a line symmetry of two or more axes when viewed from the normal direction of the liquid crystal panel. The planar shape of the light shielding part viewed from the normal direction of the base material is an anisotropic shape having a major axis and a minor axis,
The liquid crystal display device according to claim 6, wherein an extending direction of the long axis of the light shielding portion substantially coincides with a vertical direction of the screen, and an extending direction of the short axis substantially coincides with a horizontal direction of the screen.   The extending direction of the major axis and the extending direction of the minor axis of the light shielding part are substantially the same as the extending direction of the polarizing axis of the first polarizing plate and the extending direction of the polarizing axis of the second polarizing plate. The liquid crystal display device according to claim 7, which matches.   The liquid crystal display device according to claim 8, wherein an extending direction of the long axis of the light shielding portion and an extending direction of the long axis of the ellipse are substantially orthogonal to each other.   The liquid crystal display device according to claim 1, wherein the light incident end surface of the light collecting member is a concave surface including at least a curved surface.   2. The liquid crystal according to claim 1, wherein the inclined surface of the light collecting member changes in a direction in which an inclination angle with respect to an optical axis of the light collecting member increases sequentially from the light incident end surface toward the light emitting end surface. Display device.   The liquid crystal display device according to claim 1, wherein the illumination device further includes a diffusion plate positioned on a light emission side of the plurality of light collecting members.   The liquid crystal display device according to claim 12, wherein the plurality of light emitting elements are arranged at substantially equal intervals, and a distance between the adjacent light emitting elements is smaller than a distance between the light emitting elements and the diffusion plate.   The liquid crystal display device according to claim 13, wherein L / D ≦ 0.7 is satisfied, where L is a distance between adjacent light emitting elements and D is a distance between the light emitting elements and the diffusion plate. The diffusion plate has anisotropy in light diffusion characteristics,
The liquid crystal display device according to claim 12, wherein a direction in which the diffusivity of the diffusion plate is small substantially matches a horizontal screen direction of the liquid crystal panel. The absorption axis of the first polarizing plate and the absorption axis of the second polarizing plate are orthogonal to each other,
The liquid crystal panel includes a plurality of pixels having four domains oriented in four directions in which directors of liquid crystal molecules of the liquid crystal layer intersect the absorption axis of the first polarizing plate and the absorption axis of the second polarizing plate. The liquid crystal display device according to claim 1, comprising:

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