JP2005183029A - Lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce moire generating between an electro-optical panel and a light guide plate in a reverse prism type lighting system. <P>SOLUTION: The lighting system is a surface emitting type lighting system, and has a light guide plate having a rectangular flat surface and a prism sheet having a recessed and projecting shape on the side facing a light outgoing surface of the light guide plate. A plurality of almost parallel linear prisms are installed on the light outgoing surface in the light guide plate in order to enhance diffusion properties of light emitted from the light guide plate, and the linear prisms has an inclined angle larger than 0 degree to the end surface of the light guide plate in the extending direction of the linear prisms. The linear prism is formed so as to incline to the end surface of the rectangular light guide plate. Since a liquid crystal device or the like which is a lighting object of the lighting system contains a black matrix, a color filter, an electrode, and other linear elements on the inside, and if the linear prism is formed in parallel to the end surface of the light guide plate, moire is easily generated between the linear prism and the linear element such as the liquid crystal device. Therefore, by declining the linear prism on the light guide plate, the generation of the moire is suppressed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a lighting device, and more particularly to a surface-emitting type lighting device suitable as a backlight unit such as a liquid crystal device.

  In a liquid crystal device, a backlight unit is provided on the back side of a liquid crystal panel or the like in order to perform transmissive display. In general, the backlight unit includes a light source, a light guide plate that emits light from the light source as planar light, a prism sheet that directs light emitted from the light guide plate toward an object to be illuminated such as a liquid crystal panel, and the like. It is configured with. In this case, the prism sheet is arranged such that the prism-shaped surface (uneven surface) of the prism sheet is arranged toward the object to be illuminated (hereinafter referred to as “positive prism type” for convenience of explanation) and the prism. It is known that the prism-shaped surface of the sheet is disposed toward the light guide plate side (hereinafter referred to as “reverse prism type” for convenience of explanation). Recently, a linear prism is formed on a light emitting surface (hereinafter referred to as “light emitting surface”) of the light guide plate in order to diffuse light emitted from the light guide plate and prevent uneven brightness. Techniques are known.

  In a liquid crystal device or the like, when a liquid crystal panel is placed on a backlight unit, light interference (moire) occurs due to the linear prism on the light exit surface of the light guide plate, the prism of the prism sheet, and the pattern of the liquid crystal panel. There is.

  In a regular prism type backlight unit, since a diffusion sheet is generally provided between the light exit surface of the light guide plate and the prism sheet, the light guide plate and the liquid crystal panel are provided between the light guide plate and the prism sheet. It is unlikely that moire will occur between the two. In addition, moire generated between the prism sheet and the liquid crystal panel can be avoided by rotating the direction of the linear prism on the prism sheet. For example, Patent Document 1 discloses a method of inclining the direction of a linear prism on a prism sheet in a positive prism type backlight unit.

  On the other hand, in the reverse prism type backlight unit, since a diffusion sheet or the like cannot be disposed between the light guide plate and the prism sheet, the diffusibility of light emitted from the light guide plate cannot be improved, and There is a high possibility that moire occurs between the linear prism and the liquid crystal panel.

Japanese Patent No. 3410766

  The present invention has been made in view of the above points, and an object of the present invention is to reduce moire generated between an electro-optical panel and a light guide plate in a so-called reverse prism type illumination device.

  In one aspect of the present invention, the lighting device has a rectangular planar shape, a light guide plate having a plurality of substantially parallel linear prisms on the light output surface, and an uneven shape on the side facing the light output surface of the light guide plate. The linear prism has an inclination angle larger than 0 degree with respect to the side of the light guide plate along the extending direction of the linear prism.

  The illumination device is a surface-emitting illumination device suitable for, for example, a backlight unit of a liquid crystal device, and has a light guide plate having a rectangular planar shape and an uneven shape on the side facing the light output surface of the light guide plate. And a prism sheet. In order to enhance the diffusibility of light emitted from the light guide plate, the light guide plate is provided with a plurality of substantially parallel linear prisms on the light exit surface, and the linear prism is an extension of the linear prism. An inclination angle greater than 0 degrees with respect to the side of the light guide plate along the direction. That is, the linear prism is formed to be inclined with respect to the side of the rectangular light guide plate. A liquid crystal device or the like, which is an object to be illuminated of a lighting device, contains many black matrixes, color filters, electrodes, and other linear elements inside. Therefore, when a linear prism is formed parallel to the side of the light guide plate, the linear prism Moire is likely to occur between the liquid crystal device and a linear element such as a liquid crystal device. Therefore, the generation of moire is suppressed by inclining the linear prism.

  In another aspect of the present invention, the lighting device includes a light source, a light guide plate that has a plurality of substantially parallel linear prisms on the light output surface, and outputs light from the light source from the light output surface, and the light guide plate. A prism sheet having a concavo-convex shape on the side facing the light exit surface of the light source, and the linear prism is arranged along a direction in which the light guide plate guides light from the light source. An inclination angle greater than 0 degrees with respect to the vertical direction.

  The illuminating device is a surface-emitting illuminating device suitable for a backlight unit of a liquid crystal device, for example, and includes a light source, a light guide plate, and a prism sheet having an uneven shape on the side facing the light exit surface of the light guide plate. Is provided. In order to enhance the diffusibility of light emitted from the light guide plate, the light guide plate is provided with a plurality of substantially parallel linear prisms on the light output surface. The linear prism is guided by the light guide plate from the light source. It is arranged along the light emitting direction and has an inclination angle larger than 0 degree with respect to a direction perpendicular to the light source arranging direction. That is, the linear prism is formed to be inclined with respect to a direction perpendicular to the arrangement direction of the point light sources. A liquid crystal device or the like that is an object to be illuminated includes a large amount of black matrix, color filter, electrode, and other linear elements inside. Therefore, if linear prisms are formed perpendicular to the light source arrangement direction, Moire tends to occur between the prism and a linear element such as a liquid crystal device. Therefore, the generation of moire is suppressed by inclining the linear prism.

  In still another aspect of the present invention, an illumination device includes a light source, a light guide plate that has a plurality of substantially parallel linear prisms on a light exit surface, and emits light from the light source from the light exit surface, and the light guide. A prism sheet having a concavo-convex shape on the side facing the light exit surface of the light plate, wherein the linear prisms are arranged facing the light guide plate in the direction of guiding light from the light source, and the light source arrangement direction With a tilt angle greater than 0 degrees.

  The illuminating device is a surface-emitting illuminating device suitable for a backlight unit of a liquid crystal device, for example, and includes a light source, a light guide plate, and a prism sheet having an uneven shape on the side facing the light exit surface of the light guide plate. Is provided. In order to enhance the diffusibility of light emitted from the light guide plate, the light guide plate is provided with a plurality of substantially parallel linear prisms on the light output surface. The linear prism is guided by the light guide plate from the light source. And an inclination angle larger than 0 degrees with respect to the arrangement direction of the light sources. That is, the linear prism is formed to be inclined with respect to the arrangement direction of the light sources. A liquid crystal device or the like, which is an object to be illuminated, includes a large number of black elements, color filters, electrodes, and other linear elements inside. Therefore, when a linear prism is formed in parallel to the light source arrangement direction, the linear prism Moire is likely to occur between the liquid crystal device and a linear element such as a liquid crystal device. Therefore, the generation of moire is suppressed by inclining the linear prism.

  In a preferred embodiment, the inclination angle is preferably 10 degrees or less, and particularly preferably 5 degrees. In a preferred embodiment, it is preferable that the concavo-convex shape is arranged substantially parallel to the arrangement direction of the light sources.

  In another aspect of the present invention, an illumination device includes: a substrate; an electro-optical material disposed on the substrate; and an electrode that is provided on the substrate and applies a voltage to the electro-optical material. A substrate, a light guide plate having a rectangular planar shape on the light exit surface, and a plurality of substantially parallel linear prisms, and a prism sheet having an uneven shape on the side facing the light exit surface of the light guide plate, The linear prism is arranged to be inclined with respect to the extending direction of the electrode.

  The illumination device includes an electro-optical device substrate, a light guide plate, and a prism sheet having a concavo-convex shape on a side facing the light output surface of the light guide plate. In order to enhance the diffusibility of light emitted from the light guide plate, the light guide plate is provided with a plurality of substantially parallel linear prisms on the light output surface, and the linear prisms extend in the extending direction of the electrodes. It is tilted with respect to it. Thus, by arranging the linear prism so as to be inclined with respect to the extending direction of the electrode, it is possible to suppress the occurrence of moire between the linear prism and the electrode.

  In another aspect of the present invention, an illumination device includes: a substrate; an electro-optical device substrate including a substrate; an electro-optical material disposed on the substrate; and a plurality of color filters provided on the substrate; A linear light guide plate having a rectangular shape and having a plurality of substantially parallel linear prisms on the light output surface; and a prism sheet having a concavo-convex shape on the side facing the light output surface of the light guide plate, Are inclined with respect to the arrangement direction of the color filters.

  The illumination device includes an electro-optical device substrate, a light guide plate, and a prism sheet having a concavo-convex shape on a side facing the light output surface of the light guide plate. In order to enhance the diffusibility of light emitted from the light guide plate, the light guide plate is provided with a plurality of substantially parallel linear prisms on the light output surface, and the linear prisms extend in the extending direction of the color filter. It is arranged incline with respect to. Thus, by arranging the linear prism so as to be inclined with respect to the extending direction of the electrodes, it is possible to suppress the occurrence of moire between the linear prism and the color filter.

  In another aspect of the present invention, an illumination device includes a substrate, an electro-optical material disposed on the substrate, and a light shielding layer provided on the substrate and disposed between pixels. And a light guide plate having a rectangular planar shape on the light exit surface and having a plurality of substantially parallel linear prisms, and a prism sheet having an uneven shape on the side facing the light exit surface of the light guide plate, The linear prism is arranged to be inclined with respect to the extending direction of the light shielding layer. Thus, by arranging the linear prism so as to be inclined with respect to the extending direction of the light shielding layer, it is possible to suppress the occurrence of moire between the linear prism and the light shielding layer.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 shows a schematic configuration of a lighting apparatus according to the first embodiment of the present invention. In FIG. 1, an illuminating device 10 is a surface-emitting illuminating device used as a backlight unit such as a liquid crystal device 2, and includes a light guide plate 11, a light source 12, a reflective sheet 13, and a prism sheet 14. . The light L emitted from the illumination device 10 illuminates the liquid crystal device 2 from the back as shown. Thereby, the transmissive display of the liquid crystal device 2 becomes possible.

  In the liquid crystal panel constituting the liquid crystal device 2, for example, a black matrix, a color filter, electrodes, and many other components are formed in a matrix (lattice) or stripes (linear). Hereinafter, these components are referred to as “linear elements” of the liquid crystal device. FIG. 1 schematically shows the linear element 2a. These linear elements 2 a are formed substantially parallel to the four sides of the normally rectangular liquid crystal device 2.

  FIG. 2A shows a side view of the illumination device 10. 3A is a perspective view of the light guide plate 11, and FIG. 4 is a plan view of the light guide plate 11 as viewed from above in FIG.

  The light source 12 includes a plurality of LEDs 12 a and emits light to an end surface (hereinafter referred to as “light incident end surface”) 11 c of the light guide plate 11 facing the light source 12. The light guide plate 11 has a rectangular planar shape and is made of a transparent resin such as an acrylic resin. The upper surface 11a in FIGS. 1 and 2 is a surface that emits light (hereinafter referred to as “light-emitting surface”), and the lower surface 11b is a surface that reflects light (hereinafter referred to as “reflecting surface”). ).

  The light L emitted from the light source 12 enters the light guide plate 11 from the light incident end surface 11c, and is repeatedly reflected between the reflecting surface 11b and the light emitting surface 11a. When the angle between the light exit surface 11a and the light exceeds the critical angle, the light exits the light exit surface 11a and exits to the outside.

  The prism sheet 14 is a sheet having a substantially triangular cross section formed on one side thereof, and has a role of efficiently directing light emitted from the light exit surface 1 a of the light guide plate 11 toward the liquid crystal device 2. The prism sheet 14 of this embodiment is called an inverted prism type, and is arranged so that the uneven shape of the prism faces the light output surface 11 a of the light guide plate 11. As shown in FIG. 2, the light L emitted from the light exit surface 11 a of the light guide plate 11 is directed in a substantially vertical direction by the prism sheet 14.

  A predetermined pattern is formed on the reflecting surface 11b of the light guide plate 11 in order to change the angle of light. An example of such a pattern is shown in FIG. As shown in FIG. 3B, a stepped (stepped) pattern 19 is formed on the reflecting surface 11 b of the light guide plate 11. This pattern 19 changes the direction of light incident on the reflecting surface 11b. The light that has entered the light guide plate 11 is changed in direction by the reflection surface 11b, and is emitted from the light guide plate 11 to the outside when the angle with the light output surface 11a exceeds a critical angle.

  Furthermore, as shown in FIGS. 3 and 4A, the light guide plate 11 of the present embodiment has a plurality of linear prisms 30 formed on the light output surface 11a. The plurality of linear prisms 30 are formed substantially parallel to each other as illustrated. FIG. 3B shows a cross-sectional view taken along a cross section Y1-Y2 in FIG. As shown in the figure, each of the linear prisms 30 has a substantially isosceles triangle cross section, and has a function of diffusing the light L emitted from the inside of the light guide plate 11 in a direction perpendicular to the line direction. In this embodiment, the linear prism is extended in the same direction as the traveling direction of the light emitted from the LED 12a, so that the light is diffused in the direction perpendicular to that direction.

  This embodiment is characterized in that a plurality of linear prisms 30 are formed to be inclined as shown in FIG. In FIG. 4, the end surface facing the light incident end surface 11 c of the light guide plate 11 having a rectangular planar shape is defined as 11 d, and the end surface in the direction perpendicular to the light incident end surface 11 is defined as 11 s. In addition, a direction in which the LEDs 12a are arranged and arranged is a direction A, and a direction perpendicular to the direction is a direction B. As illustrated, the plurality of linear prisms 30 have an inclination angle α with respect to the end surface 11s of the light guide plate 11 along the extending direction (length direction) thereof. When the alignment direction A of the LEDs 12a is used as a reference, the plurality of linear prisms 30 have an inclination angle α with respect to a direction B perpendicular to the alignment direction A of the LEDs 12a.

  The reason for inclining the linear prism 30 in this way is as follows. As described above, many linear elements 2 a are formed on the liquid crystal panel 2 that is the object to be illuminated of the illumination device 10. Since the linear elements 2a are often in the form of a matrix or a stripe, when the linear prisms 30 formed on the light output surface 11a of the light guide plate 11 are formed in parallel to the end surface 11s, they are some of the liquid crystal panel 2. Parallel to the linear element 2a, interference (moire) occurs between the two. Therefore, in the present embodiment, the linear prism 30 formed on the light exit surface 11a of the light guide plate 11 has a predetermined inclination angle α with respect to the end surface 11s, that is, the direction B perpendicular to the alignment direction A of the LEDs 12a. Just tilt. Thereby, the some linear prism 30 on the light-guide plate 11 and the linear element 2a of the liquid crystal panel 2 become non-parallel, and generation | occurrence | production of a moire can be suppressed.

  In order to prevent the occurrence of moiré, it is necessary that the inclination angle α is larger than 0 (that is, inclined). Empirically, the inclination angle α is preferably in the range of 0 <α <10 degrees, and in particular, α = 5 degrees is optimal.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. FIG. 5 shows a plan view of the light guide plate 21 according to the second embodiment. In addition, the illuminating device 10 which concerns on 2nd Embodiment is the same as that of 1st Embodiment except the point which uses the light guide plate 21 shown in FIG. 5 instead of the light guide plate 11 of 1st Embodiment.

  As shown in FIG. 5, the light guide plate 21 of the second embodiment has a plurality of linear prisms 30 formed in the alignment direction A of the LEDs 12a. However, as in the first embodiment, the direction of the linear prism 30 is inclined by a predetermined inclination angle α. Specifically, in FIG. 5, the light guide plate 11 is inclined by an inclination angle α with respect to the end faces 21 c and 21 d of the light guide plate 11 along the extending direction of the plurality of linear prisms 30. If the LED 12a is used as a reference, the LED 12a is inclined by a predetermined inclination angle α with respect to the alignment direction A of the LEDs 12a. The magnitude of the inclination angle α is the same as in the first embodiment.

  As can be seen from FIG. 1, the liquid crystal device 2 has many linear elements 2a in a direction substantially parallel to the alignment direction A of the LEDs 12a. Therefore, when the linear prism 30 is formed on the light guide plate 11 in a direction substantially parallel to the LED 12a, there is a high possibility that moire is generated between the linear prism 30 and the linear element 2a of the liquid crystal device 2. Therefore, the linear prism 30 formed on the light guide plate 11 is inclined with respect to the direction of the end face 11c or 11d, that is, the alignment direction A of the LEDs 12a, thereby preventing the occurrence of moire.

  As described above, in the present invention, the linear prism formed on the light exit surface of the light guide plate is inclined with respect to the LED alignment direction or a direction perpendicular thereto, so that the linear prism 2a in the liquid crystal device 2 is Generation of moire in the meantime can be suppressed.

  In the above embodiment, the liquid crystal device 2 is illustrated as an object to be illuminated by the illumination device 10, but the present invention can also be applied to an electro-optical device other than the liquid crystal device 2, and in particular, an electrode for the electro-optical device Moire can be effectively suppressed when other matrix-like or stripe-like linear elements are formed.

  In the above example, a plurality of LEDs that are point light sources are used as the light source, but a linear light source such as a cold cathode tube may be used, and the present invention is not limited to the form of the light source.

It is a perspective view which shows schematic structure of the illuminating device which concerns on 1st Embodiment of this invention. It is a side view which shows the structure of an illuminating device. It is a perspective view of the light-guide plate which has a linear prism. It is a top view of the light-guide plate which has a linear prism. It is a top view of the light-guide plate which concerns on 2nd Embodiment.

Explanation of symbols

2 liquid crystal device, 10 lighting device, 11 light guide plate, 12 light source,
13 reflection sheet, 14 prism sheet, 30 linear prism

Claims (9)

A light guide plate having a rectangular planar shape and having a plurality of substantially parallel linear prisms on the light exit surface;
A prism sheet having a concavo-convex shape on the side facing the light exit surface of the light guide plate,
The illuminating device, wherein the linear prism has an inclination angle greater than 0 degree with respect to a side of the light guide plate along an extending direction of the linear prism. A light source;
A light guide plate having a plurality of substantially parallel linear prisms on the light exit surface, and emitting light from the light source from the light exit surface;
A prism sheet having a concavo-convex shape on the side facing the light exit surface of the light guide plate,
The linear prism is arranged along a direction in which the light guide plate guides light from the light source, and has an inclination angle larger than 0 degree with respect to a direction perpendicular to the arrangement direction of the light sources. Lighting device. A light source;
A light guide plate having a plurality of substantially parallel linear prisms on the light exit surface, and emitting light from the light source from the light exit surface;
A prism sheet having a concavo-convex shape on the side facing the light exit surface of the light guide plate,
The illuminating device, wherein the linear prism is arranged to face the light guide plate in a direction of guiding light from the light source, and has an inclination angle larger than 0 degrees with respect to the arrangement direction of the light source.   The lighting device according to any one of claims 1 to 3, wherein the inclination angle is 10 degrees or less.   The lighting device according to any one of claims 1 to 3, wherein the inclination angle is 5 degrees.   The lighting device according to claim 2, wherein the uneven shape is arranged substantially parallel to an arrangement direction of the light sources. A substrate for an electro-optical device, comprising: a substrate; an electro-optical material disposed on the substrate; and an electrode provided on the substrate for applying a voltage to the electro-optical material;
A light guide plate having a rectangular planar shape and having a plurality of substantially parallel linear prisms on the light exit surface;
A prism sheet having a concavo-convex shape on the side facing the light exit surface of the light guide plate,
The linear prism is arranged to be inclined with respect to the extending direction of the electrode. A substrate for an electro-optic device, comprising: a substrate; an electro-optic material disposed on the substrate; and a plurality of color filters provided on the substrate.
A light guide plate having a rectangular planar shape and having a plurality of substantially parallel linear prisms on the light exit surface;
A prism sheet having a concavo-convex shape on the side facing the light exit surface of the light guide plate,
The linear prism is arranged to be inclined with respect to the arrangement direction of the color filters. A substrate for an electro-optical device, comprising: a substrate; an electro-optical material disposed on the substrate; and a light-shielding layer provided on the substrate and disposed between the pixels;
A light guide plate having a rectangular planar shape and having a plurality of substantially parallel linear prisms on the light exit surface;
A prism sheet having a concavo-convex shape on the side facing the light exit surface of the light guide plate,
The linear prism is arranged to be inclined with respect to the extending direction of the light shielding layer.

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