JP2010217349A - Liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display having a backlight optical system and a backlight light source each of which includes enhanced optical uniformity of luminance and chromaticity and includes, as a result, high light utilizing efficiency. <P>SOLUTION: The liquid crystal display includes a liquid crystal panel, the backlight light source using a plurality of light emitting diode light sources 3 and an optical member 5 disposed on the rear surface of the liquid crystal panel. In the liquid crystal display, a plurality of prism parts 25 each formed from a plurality of inclined surfaces are disposed in a row on a surface of the optical member 5 in which light from the backlight light source is made incident and groove parts 26 are formed between adjacent inclined surfaces in the optical member 5. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a backlight optical system and a light source module of a liquid crystal display device.

  Conventionally, in order to improve the optical uniformity of luminance and chromaticity in a panel of a liquid crystal display device, measures have been taken against the optical system of the backlight. The optical system of the backlight includes optical members such as a diffusion plate, a diffusion sheet, and a prism sheet. In a large liquid crystal display, the backlight optical system has been designed for a cathode ray tube lamp.

  In recent years, a light-emitting diode light source has been used for a backlight of a liquid crystal display device. However, the optical system of the backlight is not designed in consideration of the light emission distribution of the light-emitting diode that is a point light source, and is designed to ensure sufficient by improving the optical uniformity of brightness and chromaticity. It cannot be said that it has been done. Here, Patent Document 1 and Patent Document 2 disclose a description that measures have been taken for the optical system of the backlight so far in consideration of the light emission distribution and characteristics of the light-emitting diode light source.

  Patent Document 1 discloses a configuration in which periodic grooves are formed in an optical plate in a backlight unit of a liquid crystal display device, and two types of collimating lenses are provided in a local region. Then, it describes that the backlight is reflected by the groove and further spreads to improve the uniformity of the screen. Patent Document 2 discloses a backlight having a reverse prism type light guide plate that is provided with a groove portion having a reflective surface that reflects in an oblique direction in a light guide plate and efficiently enters a reverse prism sheet. Accordingly, it is stated that the light use efficiency in the transmission mode can be improved, and the luminance and optical uniformity are improved.

JP 2006-134881 A JP 2006-138975 A

  As described above, it is necessary to improve optical uniformity in a backlight light source using a light emitting diode light source. Here, when the liquid crystal display device is further reduced in thickness, the optical distance of the backlight is reduced, so that unevenness in the brightness and chromaticity of the backlight due to the light emitting diodes becomes remarkable, and measures against optical unevenness. Is an issue.

  In addition, a backlight optical system is required to have a configuration with high light utilization efficiency with reduced light loss.

  Accordingly, it is an object of the present invention to provide a liquid crystal display device including a backlight optical system and a backlight light source that improve the optical uniformity of luminance and chromaticity and have high light utilization efficiency.

  In order to solve the above problems, a liquid crystal display device according to the present invention includes a liquid crystal panel, a backlight source using a plurality of light emitting diode light sources, and an optical member disposed on the back surface of the liquid crystal panel. A plurality of prism portions formed from a plurality of inclined surfaces are arranged in a row on a surface of the optical member on which light from the backlight light source is incident, and in the optical member, A groove is formed between them.

  In one aspect of the liquid crystal display device according to the present invention, the groove portion has at least two inclined surfaces inclined at an inclination angle larger than the plurality of inclined surfaces in the prism portion, and is higher than a height of the prism portion. It is formed so as to be deep.

  In one aspect of the liquid crystal display device according to the present invention, each of the prism portions has at least two slopes, so that a cross section is formed in a triangular shape, and the groove portions are ridge lines or valleys formed by the two slopes. It is characterized by being formed so as to divide the two slopes along a line.

  In the liquid crystal display device according to the aspect of the invention, the plurality of light emitting diode light sources may be disposed at positions opposite to the liquid crystal panel with respect to the optical member, and the optical member may emit the plurality of light emitting elements. A diffusing member that scatters light emitted from a diode light source and emits the light toward the liquid crystal panel, wherein the prism portion is disposed on a surface of the diffusing member opposite to the liquid crystal panel according to the arrangement of the light emitting diode light sources. And the said groove part is formed, It is characterized by the above-mentioned.

  In the liquid crystal display device according to the aspect of the invention, the diffusing member may include a prism portion so that a ridge line and a valley line are formed in a direction along a predetermined direction, and the groove portion It is formed in a stripe shape along at least one of the ridgeline or the valley line.

  In one aspect of the liquid crystal display device according to the present invention, the prism portion causes light emitted from one of the light emitting diode light sources at a predetermined radiation angle to enter the optical member and travel toward the groove portion. The groove portion raises the light refracted by the prism portion so that an emission angle from the surface of the optical member on the liquid crystal panel side is smaller than the predetermined radiation angle. It is made to reflect.

  In one aspect of the liquid crystal display device according to the present invention, the groove portion reflects the light emitted from one of the light emitting diode light sources at the predetermined radiation angle and refracted by the prism portion to totally reflect the liquid crystal. The light is emitted from the surface on the panel side.

  In one mode of the liquid crystal display device according to the present invention, the liquid crystal panel includes a lower polarizing plate having a transmission axis in a direction parallel to the ridge line and the valley line, and the groove portion of the light emitting diode light source Perpendicular to the ridgeline and valley line by reflecting light emitted from one at a azimuth angle perpendicular to the ridgeline and valley line at a radiation angle within a predetermined range at an angle smaller than the total reflection angle. The ratio of the polarization component in the direction is reduced and reflected toward the liquid crystal panel.

  In one aspect of the liquid crystal display device according to the present invention, one of the light emitting diodes emits light so that the emission intensity is higher at a higher radiation angle than a lower radiation angle, and the prism portion is The light having the radiation angle on the low angle side is incident and refracted toward the surface on the liquid crystal panel side, and the light is emitted from the optical member, and the light having the radiation angle on the high angle side is incident on the groove portion. The groove portion reflects the light of the high-angle side radiation angle refracted by the prism portion toward the liquid crystal panel side surface, whereby the surface of the optical member on the liquid crystal panel side The emission angle from the angle is made smaller than the radiation angle on the high angle side.

  In one aspect of the liquid crystal display device according to the present invention, at least two inclined surfaces are alternately arranged on the surface of the optical member on which light from the backlight light source is incident, so that the cross section is formed in a triangular shape. The plurality of prism portions to be arranged are arranged in a row, and the groove portion is formed between the two inclined surfaces alternately arranged in the optical member.

  In the liquid crystal display device according to the aspect of the invention, the plurality of light emitting diode light sources may be disposed on a side of the optical member, and the optical member may receive light from the plurality of light emitting diode light sources from the side. A light guide plate that guides light so as to enter and exit toward the liquid crystal panel, and a surface on which light from the light emitting diode light source of the light guide plate is incident according to the arrangement of the light emitting diode light source A prism part and the groove part are formed.

  In the liquid crystal display device according to the aspect of the invention, the diffusing member may scatter light that is bonded to the transparent film and travels from the transparent film, on which the prism portion and the groove portion are formed. It is characterized by including a diffusion plate or a diffusion sheet that emits light toward the liquid crystal panel.

  In one mode of the liquid crystal display device according to the present invention, a prism having at least two inclined surfaces corresponding to the groove is formed on the surface of the diffusion member on the liquid crystal panel side.

  In one aspect of the liquid crystal display device according to the present invention, an optical film is disposed between the diffusion member and the liquid crystal panel, and the diffusion member has a flat surface on the liquid crystal panel side, A prism having at least two slopes corresponding to the groove is formed on the surface of the optical film on the diffusion member side.

  In one aspect of the liquid crystal display device according to the present invention, each of the light emitting diode light sources supplies light to a predetermined region of the liquid crystal panel and emits light from one of the light emitting diode light sources at a predetermined radiation angle. Is refracted so as to enter the prism portion and travel toward the groove portion, and the light refracted by the prism portion is reflected by the groove portion, whereby one of the light emitting diode light sources emits light. The light is condensed so as to narrow the predetermined area to be supplied.

  In one aspect of the liquid crystal display device according to the present invention, the prism portion is formed to have an inclined surface inclined at an inclination angle x, and the prism portion emits light emitted from the light emitting diode light source at an emission angle θ. The liquid crystal panel side surface of the optical member is incident on the inclined surface inclined at the inclination angle x and refracted toward the groove portion, and the groove portion reflects light refracted on the inclined surface of the prism portion. The angle of light emitted from the light source is set to be smaller than the radiation angle θ, and θ−x, which is the incident angle of light emitted from the light emitting diode light source at the radiation angle θ, is 0 ° ≦ θ−x <90 °. It is characterized by being related.

In the liquid crystal display device according to the aspect of the invention, the optical member has a refractive index n, and the groove portion is perpendicular to a surface of the optical member on which light from the backlight light source is incident. The inclined surface is formed to have a slope inclined at an angle α with respect to the direction, is refracted by the slope inclined at an inclination angle x emitted from the light emitting diode light source at an emission angle θ, and inclined at an angle α. The emission angle sin ⁻¹ (n · sin (x + sin ⁻¹ (sin (θ−x) / n) −2α)) of the light reflected from the liquid crystal panel and emitted from the surface on the liquid crystal panel side is | sin ⁻¹ (n Sin (x + sin ⁻¹ (sin (θ−x) / n) −2α)) | ≦ 30 °.

In the liquid crystal display device according to the aspect of the invention, the optical member may have a refractive index n, and the prism portion may be arranged so that a ridge line and a valley line are formed in a direction along a predetermined direction. The groove portion is formed in a stripe shape along at least one of the ridge line or the valley line, and the liquid crystal panel has a transmission axis in a direction parallel to the ridge line and the valley line. The groove portion is formed having an inclined surface inclined at an angle α that is perpendicular to a surface on which light from the previous backlight source of the optical member is incident. The light is emitted from one of the light emitting diode light sources in a direction perpendicular to the ridge line and the valley line at a radiation angle θ, refracted by the slope of the prism portion inclined at an inclination angle x, and inclined at an angle α. Light incident on the slope of the groove Incident angle ^{90 ° - (x + sin -1} (sin (θ-x) / n) -α) is, 20 ° ≦ 90 ° - ( x + sin -1 (sin (θ-x) / n) -α) <45 ° Therefore, the light is reflected toward the liquid crystal panel on the slope inclined by the angle α of the groove portion by reducing the ratio of the polarization component in the direction perpendicular to the ridge line and the valley line. It is characterized by that.

  According to the present invention, the uniformity of the luminance distribution of the backlight light source including a plurality of light emitting diode light sources for the liquid crystal panel and the improvement of the light use efficiency are realized.

1 is a diagram illustrating an overall configuration of a liquid crystal display device according to Embodiment 1. FIG. FIG. 3 is a top view showing a state of a backlight light source and a backlight optical system before a liquid crystal panel is placed in the liquid crystal display device according to the first embodiment. It is a figure which shows the mode of the light emitting diode light source package which concerns on Embodiment 1. FIG. It is a figure which shows the structure of the backlight light source which concerns on Embodiment 1. FIG. 2 is a diagram illustrating a configuration of a diffusion plate according to Embodiment 1. FIG. It is a figure which shows a mode that the light ray from a backlight light source permeate | transmits the diffuser plate which concerns on Embodiment 1. FIG. It is a top view which shows the mode of the diffuser plate in which the square pyramid-shaped prism part is formed in the grid shape. It is a top view which shows the mode of the diffuser plate in which the square pyramid-shaped prism part is formed in the staggered pattern. It is a figure which shows the mode of the diffuser plate in which the groove part was formed between prism parts. It is a figure which shows a mode that the light ray from a backlight light source permeate | transmits the diffuser plate in which the groove part was formed between prism parts. It is a figure which shows the mode of the diffusion member which concerns on Embodiment 2. FIG. It is a figure which shows a mode that the light ray from a backlight light source permeate | transmits the diffusing member which concerns on Embodiment 2. FIG. It is a figure which shows the mode of the diffusion member comprised by the transparent film and diffusion plate in which the groove part was formed between prism parts. It is a figure which shows a mode that the light ray from a backlight light source permeate | transmits the diffusing member comprised with the transparent film in which the groove part was formed between the prism parts, and a diffusion plate. It is a figure which shows sectional drawing of the backlight light source and backlight optical system of the liquid crystal display device which concerns on Embodiment 3. FIG. It is a figure which shows the mode of the light-guide plate which concerns on Embodiment 3. FIG. It is a figure which shows a mode that the light ray from a backlight light source permeate | transmits the light-guide plate which concerns on Embodiment 3. FIG. It is a figure which shows the mode of the light-guide plate in which the groove part was formed between prism parts. It is a figure which shows a mode that the light ray from a backlight light source permeate | transmits the light-guide plate in which the groove part was formed between prism parts. It is a figure which shows the mode of the diffusion plate which concerns on Embodiment 4. FIG. It is a figure which shows a mode that the light ray from a backlight light source permeate | transmits the diffuser plate which concerns on Embodiment 4. FIG. It is a figure which shows the mode of the optical film which provided periodically the prism which is arrange | positioned between a diffuser plate and a liquid crystal panel and a cross section becomes a triangle shape. It is a figure which shows a mode that a light ray permeate | transmits the optical film by which the cross section of the triangle-shaped prism is periodically arrange | positioned through a diffuser plate from a backlight light source. It is a figure which shows a mode that the light ray from a backlight light source permeate | transmits the diffuser plate which concerns on Embodiment 5. FIG. It is a figure which shows a mode that the light ray from a backlight light source permeate | transmits a diffuser plate. It is a figure which shows the transmittance | permeability and reflectance of an S-polarization component and a P-polarization component in the case of entering into a material with a refractive index of 1.4 from the air. It is a figure which shows the transmittance | permeability and reflectance of an S polarization component and a P polarization component in the case of radiate | emitting in the air from a material with a refractive index of 1.4. It is a graph which shows the relationship between the inclination angle x in the case of (theta) = 60 degrees and the incident angle (beta). It is a graph which shows the relationship between the inclination angle x in the case of (theta) = 70 degrees and the incident angle (beta). It is a graph which shows the relationship between the inclination angle x in the case of (theta) = 80 degrees and the incident angle (beta). It is a graph which shows an example of the relationship between the radiation angle which a light emitting diode light source has, and light intensity.

  Hereinafter, specific embodiments according to the present invention will be described in detail with reference to the drawings. The liquid crystal display device of each embodiment according to the present invention to be described below is not limited by these embodiments, and may be implemented in different forms within the scope of the technical idea. Forms obtained by combining forms disclosed in the embodiments are also included in the present invention.

[Embodiment 1]
Embodiment 1 which concerns on this invention is demonstrated using FIGS. 1-8. FIG. 1 shows an overall configuration of a liquid crystal display device including a liquid crystal panel, a backlight optical system, and a backlight light source. As the backlight light source according to the present embodiment, a light source module of a direct type backlight used for medium-sized and large-sized liquid crystal panels is used, and a plurality of light emitting diodes regularly arranged at positions directly under the liquid crystal panel ( An LED (Light Emitting Diode) includes a light source. In FIG. 1, a backlight light source having a backlight housing 1, a printed circuit board 2, and a plurality of light emitting diode package light sources 3 provided on the printed circuit board 2, the shape of the backlight light source, and the backlight beam 4 The state of the cross section of the backlight optical system adjusted according to the light emission distribution is schematically shown. The backlight optical system includes a diffusing plate 5, a diffusing sheet 6, a prism sheet 7, and a polarization reflecting sheet 8. The liquid crystal panel includes a lower polarizing plate 9, a thin film transistor-equipped liquid crystal cell 10, an upper polarizing plate. A plate 11 is included. FIG. 2 is a top view showing the state of the backlight light source and the backlight optical system, and shows a state before the liquid crystal panel is placed. As shown in FIG. 2, a backlight optical system (and a backlight light source) is provided in a region 13 inside the support housing 12, and a drive circuit unit 14 is further disposed.

  FIG. 3 is a diagram illustrating a state of the light emitting diode package light source 3. The backlight light source in the present embodiment is configured as a light source module as shown in FIG. 4 in which a plurality of light emitting diode package light sources 3 are arranged. The light emitting diode package light source 3 (hereinafter referred to as light emitting diode light source 3) shown in FIG. 3 is, for example, a white light source, and the white light emitting diode light source 3 is formed on a base material 15 made of a resin molding material or a ceramic material. Then, the wiring pattern 16 and the reflector 17 are provided, and then the blue light-emitting diode element 19 is mounted and fixed on the die bond material 18, connected to the wiring pattern 16 by the Au wire 20, and then contains a phosphor. It is configured by sealing with a transparent resin 21. FIG. 3 shows an example of a white light source using a blue light-emitting diode element and a phosphor. However, an RGB light source that mounts and mounts red R, green G, and blue B light-emitting diode elements as light sources and balances white by mixing colors. It may be white light. As shown in FIG. 4, the backlight light source is formed by mounting the light emitting diode light source 3 on the printed board 2, connecting to the wiring of the printed board 2, and conducting.

  In the present embodiment, the backlight optical system is adjusted and configured in accordance with the arrangement of the light emitting diode light source 3 and the light emission distribution. In the backlight optical system of FIG. 1, attention is paid to the diffusion plate 5 disposed on the back surface of the liquid crystal panel, and FIG. 5 shows the configuration of the diffusion plate 5 in the present embodiment. As shown in FIG. 5, in the diffusing plate 5, on one side facing the backlight light source side, a prism portion 25 having a triangular cross section and a groove portion 26 formed at the apex angle of the prism portion 25. Are formed periodically. In other words, the prism portion 25 in FIG. 5 has two inclined surfaces that are symmetrically inclined and projecting into a convex shape so that the cross section is formed in a triangular shape, and the groove portion 26 is formed at the apex angle position of the prism portion 25. Here, the prism portion 25 may be formed by a plurality of three or more inclined surfaces, and the plurality of prism portions 25 are arranged in a row on the surface of the diffusion plate 5 on which light from the backlight light source is incident, and the groove portion 26 is formed between the slopes adjacent to each other among the plurality of slopes in the diffusion plate 5. In particular, the groove portion 26 in the present embodiment is formed in a triangular shape by a pair of two inclined surfaces, and is formed so as to separate the two inclined surfaces along a ridge line formed by the two inclined surfaces in the prism portion 25. The Further, as shown in FIG. 5, the included angle formed by the two inclined surfaces that are symmetrically inclined in the groove portion 26 formed in a triangular shape is 2α. However, the portion forming the included angle is removed, and the groove portion 26 is trapezoidal. It may be. Further, the inclination angle (90 ° −α) of the inclined surface in the groove portion 26 is formed with an inclination angle larger than the inclined angle x of the inclined surface in the prism portion 25, and the depth thereof is larger than the height of the prism portion 25. It is provided at a depth that is the size. Further, the prism portion 25 in FIG. 5 is arranged in the diffusion plate 5 in a triangular column shape so that ridge lines and valley lines are formed in a direction perpendicular to the paper surface, and the groove portion 26 extends along the ridge line. It is provided in a stripe shape.

  FIG. 6 is a diagram schematically illustrating a positional relationship between the backlight light source and the diffusion plate 5 according to the present embodiment. In the figure, a state in which a light beam is transmitted from the backlight light source to the diffusion plate 5 is shown. Of the backlight light emitted from the light emitting diode light source 3, the light emitted at a predetermined emission angle θ is represented by an arrow. Notation. As shown in the figure, a light beam emitted from the light-emitting diode light source 3 with an emission angle (radiation angle) θ first enters the prism portion 25 of the diffusion plate 5, and then refracts and is totally reflected by the groove portion 26. Further, the inclination angle x of the prism portion 25 and the included angle 2α of the groove portion 26 are adjusted. The totally reflected light beam then passes through the diffusion plate 5 and is emitted from the surface of the diffusion plate 5 on the liquid crystal panel side.

The diffusing plate 5 in the present embodiment has a function of raising the light emitted from the light emitting diode light source 3 at a high angle in the vertical direction of the diffusing plate 5. Here, the angle θ satisfies 0 ° ≦ θ−x <90 ° in relation to the angle x. This θ-x indicates an angle that is emitted from the light-emitting diode light source 3 at a radiation angle θ and is incident on an inclined surface of the prism portion 25 having an inclination angle x. Further, the angle of emission from the surface of the diffusion plate 5 on the liquid crystal panel side is sin ⁻¹ (n · sin (x · sin ⁻¹ (sin ()) with the angle θ, the angle x, the angle α and the refractive index n of the diffusion plate 5 as variables. It is shown by the relationship of θ−x) / n) −2α)). In the present embodiment, in a range where the angle θ is 0 ° ≦ θ−x <90 °, | sin ⁻¹ (n · sin (x + sin ⁻¹ (sin (θ−x) / n) −2α)) | ≦ In order to satisfy the 30 ° relationship, it is desirable that | sin ⁻¹ (n · sin (x + sin ⁻¹ (sin (θ−x) / n) −2α)) | ≦ 20 ° prism. The inclination angle x of the slope of the portion 25 is set. As a result, the light emitted from the light emitting diode light source 3 to the high angle side can be adjusted and condensed to the low angle side. The light beam having the radiation angle θ is emitted from the surface on the liquid crystal panel side while being diffused by being scattered when passing through the diffusion plate 5. However, when the light beam having the radiation angle θ is emitted from the surface on the liquid crystal panel side, it is emitted while being spread around the emission angle when it is not scattered. The light beam that is emitted while being processed is approximately handled as a light beam that is emitted from the diffusion plate 5 without being scattered. For this reason, description about the light ray which received scattering in each embodiment shall be omitted.

  Further, the high-angle light beam emitted from the light-emitting diode light source 3 has a higher reflectance on the surface and inside of the diffusion plate 5 and on the liquid crystal panel-side light emission surface, and is lower than the light beam on the low-angle side in the liquid crystal panel direction. It was difficult to ensure effective use of brightness. On the other hand, in this embodiment, by adjusting the angle of the slopes of the prism portion 25 and the groove portion 26 of the diffusion plate 5, the emitted light on the high angle side of the light-emitting diode light source 3 is made to the diffusion plate 5. It is possible to emit (rise up) close to the vertical direction. Thereby, it is possible to effectively use the light on the high angle side emitted from the light emitting diode light source 3 that is difficult to be used effectively, leading to an effect of increasing the light utilization efficiency. Thereby, the power efficiency of a backlight light source can be improved and the backlight light source which can be driven with lower power consumption can be realized.

  Further, in the present embodiment, since a plurality of light emitting diode light sources 3 are used as the backlight light source, in the liquid crystal display device according to the present embodiment, an area in which light is irradiated from the backlight light source toward the liquid crystal panel is arbitrarily controlled. You may make it employ | adopt the area control to perform. By performing area control in the liquid crystal display device according to the present embodiment, each of the plurality of light-emitting diode light sources 3 irradiates light to an irradiation region located immediately above it. In particular, since the prism portion 25 and the groove portion 26 are formed on the diffusion plate 5, the light from the light-emitting diode light source 3 is condensed on the irradiation region of the liquid crystal panel located immediately above the light-emitting diode light source 3 (other adjacent ones). Light is shielded so that the amount of light traveling to the irradiation area by the light-emitting diode light source 3 is reduced), and the irradiation area is prevented from expanding in a halo shape. Therefore, the contrast is improved between the area irradiated with light from the light emitting diode light source and the area not irradiated with light during the area control.

  Further, regarding the configuration of the diffusion plate 5, in addition to the configuration described above, a prism portion 25 having a plurality of slopes in a grid pattern in accordance with the light-emitting diode light sources 3 regularly arranged in rows and columns is diffused. It may protrude from the plate 5 and be provided in a convex shape. Specifically, as shown in FIGS. 7 and 8, the prism portion 25 is provided in a quadrangular pyramid shape, and the groove portion 26 is a valley line formed between two prism portions 25 between adjacent slopes. It is formed in a concave shape along. According to the arrangement of the light-emitting diode light sources 3, the prism portions 25 are arranged in a lattice shape in FIG. 7, or the prism portions 25 are arranged in a staggered manner in FIG.

  In the present embodiment, the prism portion 25 and the groove portion 26 are formed on the diffusion plate 5, but these may be formed using a diffusion sheet instead of the diffusion plate 5. The optical distance between the diffusing plate 5 and the light-emitting diode light source 3 can be reduced by matching the dimensional design of the prism portion 25 in the diffusing plate 5 with the shape design of the high angle distribution in the orientation of the light-emitting diode light source 3. It can be adjusted from a thin type corresponding to a distance of about 5 to 10 mm to a thick type corresponding to an enlarged long distance of 50 to 60 mm. In the present embodiment, the prism portion 25 and the groove portion 26 are provided according to the arrangement of the light emitting diode light source 3. Specifically, the prism portion 25 and the groove portion 26 are disposed substantially symmetrically with respect to the central axis of the light-emitting diode light source 3, and light having a radiation angle on the high-angle side of the light-emitting diode light source 3 is emitted from the prism portion 25. The light enters the diffusion plate 5 from the slope. Here, the high angle side means light emitted from the light-emitting diode light source 3 at an emission angle of 45 ° or more in the present embodiment.

  In the present embodiment, the groove 26 is formed between two inclined surfaces of the prism portion 25 having a triangular cross section. However, the groove 26 may be formed between the two prism portions 25. 9 and 10 are views showing a state in which the groove portion 26 is formed along a valley line formed between the prism portions 25 in the diffusing plate 5, and a plurality of prism portions 25 arranged in a row. At least two slopes are alternately arranged so that each of the cross sections has a triangular shape, and the groove portion 26 is placed between the two slopes forming the valley line. The groove portion 26 is formed so as to divide the two slopes forming the valley line, and the light emitted from the light emitting diode light source 3 on the high angle side is formed on the ridge line of the prism portion 25. Similarly, the light is collected. In addition, as compared with the case where the prism portion 25 and the groove portion 26 are formed as shown in FIGS. 5 and 6, the light-emitting diode light source 3 and the diffusion plate 5 are brought closer to each other and arranged with a shorter optical distance. can do.

  Note that the prism portion 25 in the present embodiment has a triangular cross section, and its ridge line and valley line are parallel to one direction. Therefore, triangular prism-like prism portions 25 are arranged in a row on the diffusion plate 5. Here, although the cross section of the prism portion 25 is triangular, for example, even when the prism portion 25 is formed by a plurality of slopes of 3 or more, or when a vertex angle of 2 or more is formed. The case where the overall shape is close to a triangular shape is also included. Further, in the present embodiment, the groove portion 26 is formed at a position where the two inclined surfaces of the prism portion 25 form a ridge line, but may be formed between two adjacent inclined surfaces. Specifically, as in the case of FIG. 5 and the like, two adjacent slopes may be two of a plurality of slopes belonging to the same prism portion 25, or as in the case of FIG. 9 and the like. The case where two adjacent slopes belong to different prism portions 25 may be used. Moreover, the case where the two inclined surfaces of the prism portion 25 are adjacent to each other through a flat portion having an inclination angle of 0 ° and the groove portion 26 is formed in the flat portion may be used.

[Embodiment 2]
Next, Embodiment 2 according to the present invention will be described with reference to FIGS.

  In the first embodiment, the optical member in which the groove part 26 and the prism part 25 are formed is the diffusion plate 5. On the other hand, in the second embodiment, the prism portion 25 and the groove portion 26 are made of a flexible transparent film 29, and the transparent film 29 is bonded to the diffusion plate 24, whereby the prism portion 25 and the groove portion 26 are formed on the diffusion plate 24. The diffusion member 5 is configured. Although the second embodiment is different from the first embodiment in the configuration of the optical member, the other points are substantially the same as those of the first embodiment, and thus description thereof is omitted. FIG. 11 is a diagram illustrating a state of the diffusing member 5 in the second embodiment, and FIG. 12 is a diagram illustrating a positional relationship between the backlight light source and the diffusing member 5 in the second embodiment. In FIG. 12, similarly to FIG. 6, the light emitted at a predetermined emission angle θ among the backlight light emitted from the light emitting diode light source 3 is represented by an arrow as a representative.

  When forming the optical member according to the second embodiment, first, the transparent film 29 having the shapes of the prism portion 25 and the groove portion 26 similar to those in FIGS. A method of integrating them by a process of attaching to the diffusion plate 24 is adopted. Further, in the example of the diffusing member 5 shown in FIGS. 13 and 14, first, the transparent film 30 having the shape described in the prism portion 25 and the groove portion 26 similar to those in FIGS. 9 and 10 in the first embodiment is manufactured. Then, a method of integrating them by a process of attaching to the diffusion plate 24 is employed. Here, it is desirable that the transparent films 29 and 30 have a refractive index comparable to that of the diffusion plate 24 in order to suppress reflection at the boundary with the diffusion plate 24 as much as possible.

  According to the method described above, the flexible transparent film 29 or 30 is easy to handle and can be given a predetermined shape with a roll mold, so a large amount of a diffusing member having a larger size is reproduced. It becomes possible to produce with good property. The transparent film 29 or 30 having the shape of the prism portion 25 or the like may be attached to a diffusion sheet thinner than the diffusion plate 24, or the prism portion 25 and the groove portion 25 are formed only by the transparent film 29 or 30. By configuring the optical member to be used, it can be applied as a smaller and more flexible display (for example, a liquid crystal display device having a size similar to an in-vehicle car navigation system or a mobile phone). In the case where the optical member having the prism portion 25 and the groove portion 26 is constituted only by the transparent film 29 or 30, a separate diffusion plate may be provided between the transparent film 29 or 30 and the liquid crystal panel.

  According to the second embodiment, by using a diffusion member in which a transparent film 29 or 30 in which the prism portion 25 and the groove portion 26 are mainly formed is attached to the diffusion plate 24, the uniformity of the backlight and the light utilization efficiency are improved. Improvement is realized. Compared with the diffusion plate 5 of the first embodiment, the reproducibility can be improved together with the accuracy of the prism portion 25 and the groove portion 26, so that a flexible transparent film 29 or 30 can be formed. Uniformity can be ensured.

[Embodiment 3]
In the first and second embodiments, the prism portion 25 and the groove portion 26 are formed in the optical member of the liquid crystal display device having a direct type backlight. On the other hand, the third embodiment is a liquid crystal display device having a so-called sidelight-type backlight, and the first embodiment is that the prism portion 25 and the groove portion 26 are formed on a light guide plate provided with a light emitting diode light source on the side thereof. And it is different from the second embodiment. Although Embodiment 3 will be described with reference to FIGS. 15 to 20, description of points that are substantially the same as those of Embodiment 1 or 2 will be omitted.

  First, FIG. 15 shows a cross-sectional view of a backlight light source and a backlight optical system in the liquid crystal display device according to the third embodiment. In FIG. 15, a backlight light source on which a side light type light emitting diode light source package 32 (hereinafter, light emitting diode light source 32) is mounted is provided on a printed circuit board sheet 31. Then, the backlight light source 34 is aligned with the light guide plate 33 to transmit the backlight light, and the backlight beam 34 transmitted through the light guide plate 33 is inverted prism sheet 35 and the diffusion film laminated on the liquid crystal panel side of the light guide plate 33. 36 to the liquid crystal panel (lower polarizing plate 37, thin film transistor-equipped liquid crystal cell 38, upper polarizing plate 39).

  In the third embodiment, as shown in FIGS. 16 and 17, a flexible transparent film (or a diffusion film having a diffusion function) 40 having shapes of the prism portion 25 and the groove portion 26 is attached to the light guide member 331. By attaching, the light guide plate 33 is configured.

The shape provided in the transparent film 40 is formed based on the shape described in FIGS. 5 and 6 of the first embodiment. Here, the inclination angle x of the pair of inclined surfaces in the prism portion 25 and the included angle 2α by the pair of inclined surfaces constituting the groove portion 26 may be adjusted in the same manner as in the first embodiment. The relationship between the angle θ and the angle x satisfies 0 ° ≦ θ−x <90 °, and the angle θ and the refractive index n, the angle x, and the angle α of the transparent film 40 (or the diffusion film 40) are further satisfied. The relationship is | sin ⁻¹ (n · sin (x + sin ⁻¹ (sin (θ−x) / n) −2α)) | ≦ 30 °, preferably | sin ⁻¹ (n · sin (x + sin ⁻¹ The angle x, the angle α, and the refractive index n are set so as to satisfy that (sin (θ−x) / n) −2α)) | ≦ 20 °. The light emitted from the light emitting diode light source 32 at the radiation angle θ on the high angle side becomes a backlight beam of an optical path that travels mainly along the light guide direction, as indicated by arrows in FIG. The light emitted from the light emitting diode light source 32 at the radiation angle θ on the high angle side is condensed so that the angle formed with the light guide direction in the light guide plate 33 is smaller than θ.

As shown in FIGS. 18 and 19, the light guide plate 33 is configured by attaching a flexible transparent film 41 (or a diffusion film 41) having shapes of the prism portion 25 and the groove portion 26 to the light guide member 331. You may be made to do. In this case, the shape provided in the transparent film 41 is formed based on the shape described in FIGS. 9 and 10 of the first embodiment. Here, the inclination angle x of the pair of inclined surfaces in the prism portion 25 and the included angle 2α by the pair of inclined surfaces in the groove portion 26 may be adjusted in the same manner as in the first embodiment. The relationship between the angle θ and the angle x satisfies 0 ° ≦ θ−x <90 °, and further, the angle θ, the refractive index n of the transparent film 40 (or the diffusion film 40), the angle x, and the angle α. The relationship of | sin ⁻¹ (n · sin (x + sin ⁻¹ (sin (θ−x) / n) −2α)) | ≦ 30 ° is desirable, and desirably | sin ⁻¹ (n · sin (x + sin ^{− 1} (sin (θ−x) / n) −2α)) | ≦ 20 °, the refractive index n, the angle x, and the angle α are set in advance. Outgoing light emitted from the light emitting diode light source 32 at a high angle of emission becomes a backlight ray of an optical path that travels mainly along the light guide direction, as indicated by arrows in FIG.

  Here, the transparent films 40 and 41 are required to have a refractive index comparable to that of the light guide member 331 in order to suppress reflection at the boundary with the light guide member 331 as much as possible. Needless to say, the light guide plate 33 may be configured by forming the prism portion 25 and the groove portion 26 on the side surface of the light guide member 331 without attaching the transparent films 40 and 41.

  In the third embodiment, the light guide plate 33 is used as an optical member in which the prism portion 25 and the groove portion 26 are formed in the sidelight type backlight optical system, and the light guide plate 33 is a flexible transparent film (or diffusion film) 40 or 41 is affixed to the light guide member 331. With this configuration, the light emission distribution in the region where light is provided to the liquid crystal panel by the light emitting diode light source 32 is adjusted, and the light use efficiency and uniformity are improved. In the liquid crystal display device including the light guide plate 33 according to the third embodiment, area control may be employed. The light guide plate 33 in Embodiment 3 condenses the light emission distribution on the high-angle side in the light-emitting diode light source 32 in the light guide direction, so that the luminance at the contour portion of the area where the light-emitting diode light source 32 provides light is improved. The area where the light emitting diode light sources 32 adjacent to each other provide light is limited in the same manner as in the case of the direct type. That is, as shown in FIG. 17 and FIG. 19, the irradiation area by one light-emitting diode light source 32 is suppressed from expanding in a halo shape in the horizontal direction (direction perpendicular to the light guide direction) in the figure, and the contrast is high. Area control is possible.

  As described above, in the liquid crystal display device according to the third embodiment, a low power consumption backlight light source with improved luminance, chromaticity, and light utilization efficiency is provided, and a backlight with improved contrast when performing area control. A light source is provided.

[Embodiment 4]
In the first to third embodiments, light is incident / refracted by the prism portion 25 and reflected by the groove portion 26, and then light is emitted from the surface of the optical member on the liquid crystal panel side toward the liquid crystal panel. On the other hand, the fourth embodiment is different from the above-described embodiments in that a prism is further provided on the surface of the optical member on the liquid crystal panel side or on the optical path thereafter. Except this point, since it is substantially the same, description is abbreviate | omitted.

  A fourth embodiment according to the present invention will be described with reference to FIGS. In the fourth embodiment, as shown in FIG. 20, in the diffusion plate 5, a prism having a triangular cross section is provided on one surface facing the backlight source side, as shown in FIGS. 9 and 10 of the first embodiment. The part 25 and the groove part 26 are periodically formed, and a prism having a triangular cross section formed by a pair of inclined surfaces is periodically provided on the opposite surface. As shown in FIG. 21, the light beam component reflected by the slope of the groove portion 26 in the diffusion plate 5 is reflected from the diffusion plate 5 by the prism portion 25 and the groove portion 26 in the diffusion plate 5 and the prism formed on the liquid crystal panel side. When the light is emitted, it is raised upward in the figure. Since the liquid crystal panel is located on the upper side of the diffusion plate 5, the backlight beam is incident on the liquid crystal panel in a direction closer to the vertical. As described above, this has the effect of effectively utilizing the backlight light for the liquid crystal panel and improving the light utilization efficiency of the backlight. Moreover, since the brightness | luminance of backlight light is realizable with less power consumption, it contributes to reduction of power consumption.

  Further, as shown in FIGS. 22 and 23, the diffusion plate 5 is the same as that of the first embodiment, and an optical device in which a prism having a triangular cross section is periodically provided on the liquid crystal panel side of the diffusion plate 5. The film 43 may be disposed. The light component emitted from the diffusing plate 5 as shown in FIGS. 9 and 10 of the first embodiment is raised upward in the figure by the prism of the optical film 43. In this case as well, the power consumption of the backlight light source is improved by effectively utilizing the backlight light for the liquid crystal panel and increasing the light use efficiency of the backlight, similarly to the diffusing plate 5 of FIGS. Will be reduced.

  In the case of FIGS. 20 to 23 in the above description, prisms having a triangular cross section are formed in rows on the surface of the diffusion plate 5 on the liquid crystal panel side or the optical film 43. However, these prisms only need to have slopes set according to the grooves 26 formed on the diffusion plate 5 and set the inclination angles so as to raise the light rays reflected from the grooves 26. The prisms do not have to be arranged in a row such as 20 or the like. 20 to 23, the prism portion 25 and the groove portion 26 formed on the light emitting diode side surface of the diffusion plate 5 are the prism portion 25 and the groove portion 26 corresponding to FIG. 9 and FIG. 5 and FIG. 6 may be the prism portion 25 and the groove portion 26. Regarding the diffusion plate 5, in addition to the configuration described above, a prism portion 25 having a plurality of slopes in a grid pattern is formed from the diffusion plate 5 in accordance with the light emitting diode light sources 3 regularly arranged in rows and columns. The protrusion may be provided in a convex shape. Specifically, as shown in FIGS. 7 and 8, the prism portion 27 is provided in a quadrangular pyramid shape, and a groove portion 28 is provided at a position where the valley line is formed. About the arrangement | positioning method of the prism part 27, you may arrange in a grid | lattice form or a zigzag form.

[Embodiment 5]
In the first embodiment, the light from the light-emitting diode light source 3 or 32 is collected by totally reflecting the light from the backlight light source by the groove 26. On the other hand, in the fifth embodiment, the prism portion 25, the groove portion 26, and the like are set so that the groove portion 26 reflects light by increasing the polarization component ratio in the direction of the transmission axis in the lower polarizing plate 9. This is different from the embodiment. Except this point, since it is substantially the same, description is abbreviate | omitted.

Here, Embodiment 5 according to the present invention will be described with reference to FIGS. In the fifth embodiment, the configuration of the diffuser plate 5 and the like is created in the same shape as in the first embodiment. However, as shown in FIGS. 24 and 25, the backlight beam incident from the prism portion 25 into the diffuser plate 5 is When the light is reflected by the slope formed in the groove 26, the light enters the slope at an incident angle β. This incident angle β is smaller than the critical angle for total reflection (especially around Brewster angle θ _B = tan ^-1 (1 / n)), so that the electromagnetic field vector oscillates perpendicularly to the incident surface. It is possible to obtain a light beam component in which the ratio of the S-polarized light component is increased. Here, n is the refractive index of the material constituting the diffusion plate 5.

26 and 27 are diagrams showing the calculated transmittance and reflectance of the S-polarized component and the P-polarized component when the refractive index of the material of the diffusion plate 5 is 1.4. Since the transmittance of the P-polarized component is 100% and the reflectance is 0% at the Brewster angle θ _B , the light of the P-polarized component is transmitted from the inclined surface of the groove portion 26 in FIGS. Leaked light. For this reason, it becomes a light ray with a high ratio of the S polarization component having a relatively high reflectance. As a result, the light beam component of the backlight that is emitted from the diffusion plate 5 of FIGS. 25 and 26 toward the liquid crystal panel and becomes effective for the liquid crystal panel is emphasized. The S-polarized component is arranged in such a manner that the transmission axis of the lower polarizing plate 9 of the liquid crystal panel is aligned with this polarization direction because the electromagnetic field vector vibrates in the direction perpendicular to the incident plane (the direction perpendicular to the paper surface). For this reason, the transmission axis of the lower polarizing plate 9 is a direction parallel to the ridge line and the valley line of the diffusion plate 5 (a direction parallel to the groove portions 26 arranged in a stripe shape). In this way, the S-polarized component is emphasized and the light is raised from the diffuser plate 5 and emitted, thereby reducing the reflection loss due to multiple reflection between the diffuser plate 5 and the lower polarizing plate 9, and the light utilization efficiency of the backlight. (Utilization efficiency of polarized light) can be improved. As a result, the light utilization efficiency of the backlight can be increased and the power consumption of the backlight light source can be reduced.

In the fifth embodiment, the configuration of the diffusion plate 5 that emphasizes the S-polarized component is set as described above. 24 and 25, the inclination angle x of the inclined surface of the prism portion 25, the angle 2α of the included angle of the groove portion 26, and the incident angle β to the inclined surface of the groove portion 26 are β = 90− The relationship is (x + sin ⁻¹ (sin (θ−x) / n) −α). Therefore, referring to FIG. 26 and FIG. 27, when the incident angle to the inclined surface of the prism portion 25 satisfies 0 ° ≦ θ−x <90 ° as the range of the incident angle β in which the intensity of the S-polarized light component increases. The angle x, the angle α, and the refractive index n of the diffusion plate 5 are set so as to satisfy 20 ° ≦ β <45 °.

  Here, in FIGS. 28 to 30, the refractive index of the diffusion plate 5 is set to 1.4, and the prism inclination angle x in the case of θ = 60 °, θ = 70 °, and θ = 80 °, respectively, It is a graph which shows the relationship of incident angle (beta), In each graph, the relationship is shown about (alpha) = 20 degrees, 10 degrees, and 5 degrees. In each of FIGS. 28 to 30, a range where the incident angle β is 20 ° ≦ β <45 ° is indicated by a dotted line. Here, for example, when the prism portion 25 has an inclination angle of x = 30 ° and the groove portion 26 has an included angle 2α where α = 5 °, the range of 0 ° ≦ θ−x <90 ° When θ = 60 °, 70 °, and 80 °, 20 ° ≦ β <45 ° is satisfied. The Brewster angle in the groove 26 is about 35 °. In particular, light incident on the groove 26 at an angle in the range of 20 ° to 45 ° in the vicinity thereof has an enhanced S-polarized component. By adopting the diffusion plate 5 having the angle x, the angle α, and the refractive index n satisfying the above relationship, the S-polarized component is emphasized and the backlight is provided to the lower polarizing plate 9. When separating and utilizing the S-polarized light component as described above, a member between the diffuser plate 5 and the lower polarizing plate 9 such as not arranging the polarizing reflection sheet 8 and the prism sheet 7 in FIG. You may make it arrange | position according to the diffusion plate 5. FIG. Further, the members between the diffusion plate 5 and the lower polarizing plate 9 may be arranged according to the diffusion plate 5 in the same manner in other embodiments.

  Further, in each of the above-described embodiments, it is preferable to use the light-emitting diode light source 3 (or 32) having a light emission distribution designed to increase the light intensity on the high angle side. FIG. 31 is an example of the light-emitting diode light source 3 used in each embodiment. In the figure, the relationship between the radiation angle and the light intensity is shown. By mounting a lens on the light emitting diode light source 3, a bimodal light emission distribution having a light intensity peak at a radiation angle of ± 60 ° is provided. ing. The emission angle on the high angle side (in FIG. 31, −45 ° or less and + 45 ° or more in FIG. 31) at the emission angle on the low angle side (in FIG. 31, a range larger than −45 ° and smaller than + 45 °). By using such a light emitting diode light source 3 that emits a large amount of light in the range), the light emitting diode light source 3 improves the uniformity between the outer peripheral portion and the central portion of the area that provides light to the liquid crystal panel, and the area. The contrast at the time of control can be improved. When the groove 26 is formed in a stripe shape on the diffusion plate 5 or the like, the light-emitting diode light source 3 may have a light emission distribution as shown in FIG. 31 only in a direction perpendicular to the stripe direction. However, when the groove 26 is formed in a grid shape in the vertical and horizontal directions, a light emission distribution as shown in FIG. 31 may be provided in both the vertical and horizontal directions. In the above, ± 45 ° is used as a reference for the radiation angle on the high angle side, and the high angle side is larger than the light emission amount on the low angle side, but other angles such as ± 30 ° or ± 60 ° are used. It is good also as a standard. In these cases, the light on the high angle side enters from the prism portion 25 and is reflected by the groove portion 26 to rise and exit from the diffusion plate 5, and the light on the low angle side enters from the prism portion 25. Thus, the inclination angle x of the prism portion 25, the depth of the groove portion 26, the included angle 2α, and the like are set so as to be emitted from the diffusion plate 5 without being reflected by the groove portion 26.

  In addition, in Embodiment 5, the light of the light emitting diode light source having a radiation angle on the high angle side that satisfies the condition of 0 ° ≦ θ−x <90 ° is totally reflected in the groove portion 26 in Embodiment 1, and in the groove portion 26 in Embodiment 5. The angle x, the angle α, and the refractive index n are set so as to reflect at an angle smaller than the total reflection angle (at an angle near the Brewster angle). However, the angle x or the like may be set so that a part of the light at 30 ° ≦ θ−x <90 ° is totally reflected and the remaining part is reflected at an angle smaller than the angle at which it is totally reflected. Needless to say.

  DESCRIPTION OF SYMBOLS 1 Backlight housing | casing, 2 Printed circuit board, 3 Light emitting diode package light source (light emitting diode light source), 4 Back light beam, 5 Diffusing plate (diffusion member), 6 Diffusing sheet, 7 Prism sheet, 8 Polarization reflection sheet, 9 Lower polarization Plate, 10 Thin-film transistor mounted liquid crystal cell, 11 Upper polarizing plate, 12 Backlight support housing frame, 13 Region in support housing frame, 14 Drive circuit, 15 Base material, 16 Wiring, 17 Reflector, 18 Die bond material, 19 Light emission Diode element, 20 Au wire, 21 Phosphor-containing sealing resin, 25 Prism part, 26, 28 Groove part, 27 Square pyramidal prism part, 29, 30 Transparent film, 31 Print sheet substrate, 32 Light emitting diode package light source (light emitting diode) Light source), 33 light guide plate, 331 light guide member, 34 back Light rays 35 reverse prism sheet 36 diffusion sheet 37 lower polarizer, 38 thin-film transistors mounted liquid crystal cell, 39 upper polarizer, 40, 41 transparent film, 43 an optical film.

Claims (18)

LCD panel,
A backlight source using a plurality of light emitting diode light sources;
An optical member disposed on the back surface of the liquid crystal panel,
A plurality of prism portions formed from a plurality of inclined surfaces are arranged in a row on a surface on which light from the backlight light source of the optical member is incident,
In the optical member, a groove is formed between adjacent slopes.
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 1.
The groove portion has at least two inclined surfaces inclined at a larger inclination angle than the plurality of inclined surfaces in the prism portion, and is formed to be deeper than a height of the prism portion.
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 2,
Each of the prism portions has a triangular cross section by having at least two slopes,
The groove is formed so as to divide the two slopes along a ridge line or a valley line formed by the two slopes.
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 3.
The plurality of light emitting diode light sources are arranged at positions opposite to the liquid crystal panel with respect to the optical member,
The optical member is a diffusing member that scatters light from the plurality of light emitting diode light sources and emits the light toward the liquid crystal panel,
The prism portion and the groove portion are formed on the surface of the diffusion member opposite to the liquid crystal panel according to the arrangement of the light emitting diode light source.
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 4.
In the diffusing member, a prism portion is arranged so that a ridge line and a valley line are formed in a direction along a predetermined direction,
The groove is formed in a stripe shape along at least one of the ridge line or the valley line.
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 5.
The prism portion refracts light emitted from one of the light-emitting diode light sources at a predetermined radiation angle so as to enter the optical member and travel toward the groove portion,
The groove portion raises and reflects the light refracted by the prism portion so that an emission angle from a surface of the optical member on the liquid crystal panel side is smaller than the predetermined radiation angle.
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 6.
The groove portion emits light from one of the light-emitting diode light sources at the predetermined radiation angle and refracted by the prism portion to be totally reflected and emitted from the surface on the liquid crystal panel side.
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 6.
The liquid crystal panel includes a lower polarizing plate having a transmission axis in a direction parallel to the ridge line and the valley line,
The groove portion reflects light emitted from one of the light emitting diode light sources at a radiation angle in a predetermined range in an orientation perpendicular to the ridge line and the valley line at an angle smaller than a total reflection angle, Reducing the proportion of the polarization component in the direction perpendicular to the ridge line and the valley line, and reflecting toward the liquid crystal panel;
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 4.
One of the light emitting diodes emits light so that the light emission intensity is higher at a radiation angle on a higher angle side than a radiation angle on a lower angle side,
The prism unit allows the light with the radiation angle on the low angle side to enter and refract the light toward the surface on the liquid crystal panel side and emits the light with the radiation angle on the high angle side from the optical member. Refracted toward the groove,
The groove portion reflects the light of the high-angle radiation angle refracted by the prism portion toward the surface on the liquid crystal panel side, thereby reducing the emission angle from the surface on the liquid crystal panel side of the optical member. Smaller than the radiation angle on the high angle side,
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 2,
A plurality of prism portions each having a triangular cross section are arranged in a row by alternately arranging at least two inclined surfaces on the surface of the optical member on which light from the backlight light source is incident. ,
The groove is formed between the two slopes alternately arranged in the optical member.
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 3.
The plurality of light emitting diode light sources are disposed on the side of the optical member,
The optical member is a light guide plate that guides light from the plurality of light-emitting diode light sources to be incident from the side and emitted toward the liquid crystal panel,
The prism portion and the groove portion are formed on the surface of the light guide plate on which light from the light emitting diode light source is incident, depending on the arrangement of the light emitting diode light source.
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 4.
The diffusion member includes a transparent film on which the prism portion and the groove portion are formed, and a diffusion plate or a diffusion sheet that is bonded to the transparent film and scatters the light traveling from the transparent film and emits the light toward the liquid crystal panel Comprising, and
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 4.
A prism having at least two slopes corresponding to the groove is formed on the surface of the diffusion member on the liquid crystal panel side.
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 4.
An optical film is disposed between the diffusing member and the liquid crystal panel,
The diffusion member has a flat surface on the liquid crystal panel side,
On the surface of the optical film on the diffusion member side, a prism having at least two inclined surfaces corresponding to the groove is formed.
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 1.
Each of the light emitting diode light sources supplies light to a predetermined area of the liquid crystal panel,
Light emitted from one of the light emitting diode light sources at a predetermined radiation angle is refracted so as to enter the prism portion and travel toward the groove portion,
The light refracted by the prism part is reflected by the groove part, so that one of the light emitting diode light sources is condensed so as to narrow the predetermined region to which the light is supplied,
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 1.
The prism part is formed with a slope inclined at an inclination angle x,
The prism portion allows light emitted from the light-emitting diode light source at a radiation angle θ to be incident from an inclined surface inclined at the inclination angle x and refracted toward the groove portion,
The groove portion is configured to reflect the light refracted on the inclined surface of the prism portion so that an emission angle from the surface of the optical member on the liquid crystal panel side is made smaller than the radiation angle θ.
For θ-x, which is the incident angle of light emitted from the light emitting diode light source at a radiation angle θ,
0 ° ≦ θ−x <90 °,
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 16.
The optical member has a refractive index n;
The groove portion is formed having an inclined surface inclined at an angle α with a direction perpendicular to a surface on which light from the backlight light source of the optical member is incident on the optical member,
An emission angle of light emitted from the light emitting diode light source at a radiation angle θ and refracted by the inclined surface inclined at an inclination angle x and reflected from the inclined surface inclined at an angle α and emitted from the surface on the liquid crystal panel side. sin ⁻¹ (n · sin (x + sin ⁻¹ (sin (θ−x) / n) −2α)) is | sin ⁻¹ (n · sin (x + sin ⁻¹ (sin (θ−x) / n) − 2α)) | ≦ 30 °
A liquid crystal display device characterized by the above. The liquid crystal display device according to claim 16.
The optical member has a refractive index n;
The prism portions are arranged in rows so that ridge lines and valley lines are formed in a direction along a predetermined direction.
The groove is formed in a stripe shape along at least one of the ridge line or the valley line,
The liquid crystal panel includes a lower polarizing plate having a transmission axis in a direction parallel to the ridge line and the valley line,
The groove portion is formed having an inclined surface inclined at an angle α with a direction perpendicular to a surface on which light from the backlight light source of the optical member is incident on the optical member,
The light is emitted from one of the light emitting diode light sources in a direction perpendicular to the ridge line and the valley line at a radiation angle θ, refracted by the slope of the prism portion inclined at an inclination angle x, and inclined at an angle α. The incident angle 90 ° − (x + sin ⁻¹ (sin (θ−x) / n) −α) of the light incident on the slope of the groove is 20 ° ≦ 90 ° − (x + sin ⁻¹ (sin (θ−x ) / n) −α) <45 °, and the light is inclined at an angle α of the groove portion by reducing the ratio of the polarization component in the direction perpendicular to the ridge line and the valley line. Reflected toward the liquid crystal panel on the slope,
A liquid crystal display device characterized by the above.

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