JP4452528B2 - Planar light generator, image display device - Google Patents

Description

  The present invention relates to a planar light generator that outputs planar light based on light supplied from a point light source, and an image display device using the planar light generator.

  The high resolution of displays, which has been slow in progress in CRT displays, is about to make dramatic progress with the introduction of new technologies such as liquid crystal. That is, an image display device using a liquid crystal material can display a finer image than a CRT display by performing fine processing.

  An image display device using liquid crystal utilizes the fact that the orientation of liquid crystal molecules changes according to an applied electric field, and specifically includes a liquid crystal layer containing liquid crystal molecules. The light transmittance is changed by applying an electric field according to the display image, and the light and shade according to the distribution state of the light transmittance is displayed on the screen. Therefore, in an image display device using liquid crystal, a mechanism for making light incident on the liquid crystal layer is necessary to perform image display. Usually, an image display device using liquid crystal is called a so-called backlight. It has the structure provided with the planar light generation mechanism.

  As an example of such a planar light generating mechanism, in addition to a configuration using a linear light generating mechanism such as a fluorescent tube, a mechanism using a point light source such as an LED (Light Emitting Diode) has been proposed in recent years. LEDs have the advantage that they can be driven with low power consumption and emit light with high brightness. Therefore, by providing a planar light generation mechanism using a point light source such as an LED, advantages such as low power consumption can be obtained. It is possible to realize an image display apparatus having

  FIG. 10 is a schematic diagram showing a configuration of a conventional planar light generating mechanism using a point light source. As shown in FIG. 10, a conventional planar light generation mechanism using a point light source has a plurality of point light sources 101 and a light guide that inputs light from the point light source 101, converts the light into planar light, and outputs the light. 102. The light guide 102 has a rectangular shape when viewed from the planar light emitting direction (perpendicular to the paper surface in FIG. 10), and has an incident window at a position corresponding to the vertex of the rectangle. The point light source 101 is disposed so that light enters through an incident window provided in the light guide. Further, the plurality of point light sources 101 are arranged so that the direction of the output light is directed toward the center of the light guide 102. (For example, refer to Patent Document 1.)

Japanese Patent Laid-Open No. 11-133425 (FIG. 1)

  However, the planar light generation mechanism shown in FIG. 10 has a problem that it is difficult to output planar light when actually manufactured. That is, the light guide 102 described in Patent Document 1 needs to have a function of outputting planar light based on radiation light input in a direction perpendicular to the planar light emitting direction. No specific configuration for realizing the above is disclosed in Patent Document 1, and it is difficult to output planar light only by the technical matter shown in FIG.

  Further, in the case of a planar light generation mechanism provided with a plurality of point light sources, it is not appropriate to make the structure of the light guide similar to that using a conventional linear light generation mechanism such as a fluorescent tube. This is because the light output from the point light source has a characteristic of diffusing radially as it travels, and is significantly different from the linear light output as substantially uniform planar light.

  The present invention has been made in view of the above, and an object thereof is to realize a planar light generator that outputs planar light having uniform intensity using light output from a plurality of point light sources. .

To solve the above problems and achieve the object, the planar light generating device according to the present invention, a plurality of point light sources for emitting an input light radially, a planar light by causing disturb diffusing the input light a product planar light generating device including a light scattering means for a plurality of light input window formed corresponding to the plurality of point light sources, the plurality of input through the optical input window light guiding means having a light scattering region in which the light scattering means is arranged so that the symmetry matching arrangement pattern of symmetry and before Symbol light scattering means of the intensity distribution pattern in free space of the input light from the point light source Each of the input lights is input to the light guide means from a direction perpendicular to the emission direction of the planar light, and each optical axis of the input light is perpendicular to the emission direction of the planar light in the surface, the center point of the light diffusion area and the point light source Characterized in that it deviates a predetermined angle in the same rotational direction with respect to a straight line passing through the.
Furthermore, the planar light generating device according to the present invention includes a plurality of point light sources for emitting an input light radially, the light scattering means and the planar light having a for generating a planar light by scattering the entering-force light a generating equipment, is formed corresponding to the plurality of point light sources, a plurality of light input window having a function of adjusting the definitive free spatial intensity distribution pattern of the input light from the point light sources, the light input The light scattering means is arranged so that the symmetry of the intensity distribution pattern in the free space of the input light from the plurality of point light sources inputted through the window coincides with the symmetry of the arrangement pattern of the light scattering means. And a light guide means having a light scattering region.

According to inventions of this, since it was decided to place the symmetry of the intensity distribution pattern in free space of the input light, the light scattering member such that the symmetry of the arrangement pattern of the light scattering members are matched, a plurality of point light sources It is possible to output uniform planar light even though the radiated light from is used as input light.

Further, the planar light generating device according to the present invention, in the above invention, the light scattering region, the shape of the emission direction perpendicular to the cross section of the planar light is rectangular, the light input window, the It is formed at a position corresponding to a vertex of a rectangle.

Further, the planar light generating device according to the present invention, the above-mentioned invention, the intensity distribution pattern in free space of the input light, a 2-fold symmetry with respect to a reference point of said light scattering area, the light-scattering The means is arranged so as to be symmetrical twice with respect to the reference point.

In the planar light generator according to the present invention , the intensity distribution pattern in the free space of the input light has a C _2V symmetry in the above invention, and the light scattering means is on the light scattering region. _Are arranged so as to have C _2V symmetry.

Furthermore, the planar light generating device according to the present invention, in the above invention, the light scattering region is a cross-sectional shape perpendicular and emission direction of the planar light is square-shaped, the input light, each of the square is input through the optical input window formed in correspondence with the vertices, the intensity distribution pattern in free space of the entering force light has a symmetry C _4V, said light scattering means, the light scattering region It is arranged so as to have C _4V symmetry.

An image display device according to the present invention includes an array substrate on which a pixel circuit corresponding to a display pixel is formed, a counter substrate disposed to face the array substrate, and a space between the array substrate and the counter substrate. Formed in correspondence with the plurality of point light sources, a plurality of point light sources that emit input light radially, a light scattering unit that generates planar light by scattering the input light , more so that a light input window, and the symmetry of the arrangement pattern of the light scattering means and the symmetry of the intensity distribution pattern between the free air of the input light inputted through the plurality of light input window matching the And a light guide unit having a light scattering region in which the light scattering unit is disposed, and the light input from the direction perpendicular to the emission direction of the surface light. It is input to the unit, the optical axis of the input optical , At the exit direction perpendicular the plane of the planar light, characterized in that it deviates a predetermined angle with respect to the straight line passing through the center point of the light diffusion area and the point light source. The image display apparatus according to the present invention, the array substrate on which the pixel circuits corresponding to the display pixels are formed, a counter substrate disposed to face the array substrate, and the counter substrate and the array substrate Formed corresponding to the plurality of point light sources, a liquid crystal layer enclosed between them, a plurality of point light sources that radiate input light radially, a light scattering unit that generates planar light by scattering the input light is, the input light from the plurality of the optical input window, the plurality of point light sources which is input through the optical input window that have a function of adjusting the intensity distribution pattern in free space of the input light from the point light sources Planar light generating means comprising: a light guide means having a light scattering region in which the light scattering means is arranged so that the symmetry of the intensity distribution pattern in free space matches the symmetry of the arrangement pattern of the light scattering means And having And features.

  In the planar light generating device according to the present invention, the light scattering member is arranged so that the symmetry of the intensity distribution pattern in the free space of the input light and the symmetry of the arrangement pattern of the light scattering member coincide with each other. Even though the radiated light from the point light source is used as input light, there is an effect that uniform planar light can be output.

  Further, the image display device according to the present invention has, as the planar light generating means, a plurality of point light sources that generate input light and a symmetry equal to the symmetry of the intensity distribution pattern in the free space of the input light from the point light source. It is possible to output uniform planar light despite the use of a point light source, using such a planar light. Since the image display is performed, there is an effect that it is possible to display an image with uniform luminance over the entire screen.

  Hereinafter, the best mode for carrying out an image display apparatus according to the present invention (hereinafter simply referred to as “embodiment”) will be described with reference to the drawings. It should be noted that the drawings are schematic and different from the actual ones, and it is a matter of course that the drawings include portions having different dimensional relationships and ratios. is there.

(Embodiment 1)
First, the planar light generator according to the first embodiment will be described. FIG. 1 is a schematic diagram illustrating the overall configuration of the planar light generator according to the first embodiment. As shown in FIG. 1, the planar light generator 1 according to the first exemplary embodiment includes a cross-sectional shape of the light guide member 3 in the planar light emitting direction (perpendicular to the paper surface in FIG. 1) and the vertical direction. Is formed in a substantially square shape. Further, the planar light generator 1 according to the first embodiment includes light input windows 2a to 2d for inputting light from the outside to a region corresponding to the apex of the square, and the inside of the light guide member 3. A light scattering region 4 for scattering light input from the outside.

The light input windows 2a to 2d are for inputting the radiated light output from the point light sources 5a to 5d arranged outside into the planar light generator 1. The light input windows 2a to 2d also have a function of correcting the light intensity distribution pattern in free space for the radiated light output from the point light sources 5a to 5d. Specifically, the light input windows 2a to 2d are arranged such that when the intensity distribution pattern of the radiated light output from all the corresponding point light sources 5a to 5d travels in the free space, the C _4V in the Shane-Fries symbol is used. It has a function of correcting the traveling direction of light and the like as appropriate so as to have the symmetry. Such a function is realized, for example, by appropriately adjusting the shape, refractive index, and the like of the light input windows 2a to 2d in accordance with the light output characteristics of the point light sources 5a to 5d. Specifically, the light input windows 2a to 2d have, for example, a central axis in the direction toward the central point of the light scattering region 4 for the radiated light output from each of the point light sources 5a to 5d. Have a function of correcting so that they have substantially the same symmetry with respect to each other.

The “free space” refers to a space where there is no light scattering element or the like that changes the traveling direction of light, and ideally refers to a vacuum space. That is, “having C _4V symmetry when traveling in free space” means that the light guide member from the point light sources 5a to 5d is used when there is no light scattering member 10 or the like to be described later on the light scattering region. This means that the intensity distribution pattern of the light input to 3 in the light guide member 3 has C _4V symmetry. Further, “radiated light” refers to light including a component that travels in a plurality of directions from a light source, and is a concept that includes light other than light that is uniformly radiated at all angles. Further, the “point light source” is a concept indicating all light sources that output radiated light.

  The light scattering region 4 is for generating planar light by scattering radiation emitted from the point light sources 5a to 5d via the light input windows 2a to 2d. Specifically, the light scattering member 10 described later has a configuration arranged according to a predetermined pattern, and the light scattered by the light scattering member 10 is output in a plane shape in a direction perpendicular to the paper surface of FIG. Have In addition, since the specific shape, arrangement pattern, etc. of the light-scattering member 10 are demonstrated in detail later, it abbreviate | omits here.

  2 is a cross-sectional view taken along line AA in FIG. As illustrated in FIG. 2, the planar light generating device 1 includes a light scattering region 4 on the bottom surface, a light guide member 3 having a rectangular parallelepiped shape, and light input windows 2 a to 2 d among side surfaces of the light guide member 3. And a reflecting member 7 for preventing the input light from leaking outside through the region other than the region where the light is formed or the bottom surface region of the light guide member 3. In the configuration shown in FIG. 2, the light guide member 3 and the reflection member 7 are formed separately and independently. However, for example, by performing predetermined processing on the bottom and side surfaces of the light guide member 3, the light reflection function For example, the light guide member 3 and the reflection member 7 may be integrally formed. Further, as shown in FIG. 2 (the members shown in FIG. 2 are the point light sources 5d, the point light sources 5a to 5c are also the same), the point light sources 5a to 5d include the LEDs 8 inside, and the radiation output from the LEDs 8 is provided. It has the structure which inputs light with respect to the planar light generator 1. FIG.

  Next, the light scattering member disposed in the light scattering region 4 according to a predetermined pattern will be described. A light-scattering member functions as an example of the light-scattering means in a claim, and has the function to scatter the radiated light input from the point light sources 5a-5d. FIGS. 3A to 3C are schematic views illustrating the three-dimensional structures of the light scattering members 10a to 10c. As shown in FIG. 3A, the light scattering member 10a has a rectangular parallelepiped shape, and as shown in FIG. 3B, the light scattering member 10b has a tapered shape, and as shown in FIG. The scattering member 10c has a cylindrical shape. In the planar light generating device 1 according to the first embodiment, any of the light scattering members 10a to 10c may be used as the light scattering member disposed in the light scattering region 4, and the light scattering members 10a to 10c may be used. It is good also as a structure which mixed the thing of 2 or more shapes from 10c. For this reason, below, the member which has arbitrary light scattering functions among the light-scattering members 10a-10c is called the "light-scattering member 10."

  FIG. 4 is a schematic diagram illustrating an example of a pattern in which the light scattering member 10 illustrated in FIGS. 3-1 to 3-3 is disposed on the light scattering region 4. The black dots in FIG. 4 reflect the intensity of light scattering, and specifically, the degree of arrangement density of the light scattering members 10 or the magnitude relationship of the light scattering members 10 is represented by the size of the black dots. That is, in the region where the size of the black spots is large, it means that the light scattering members 10 are densely arranged or the individual light scattering members 10 are larger in size than others.

As is clear from FIG. 4, in the first embodiment, the light scattering member 10 is arranged to have C _4V symmetry in the Shane-Fries symbol. As described above, the planar light generating device 1 according to the first embodiment, the intensity distribution pattern in free space of the light input from the outside through the light input window 2a~2d is configured to be C _4V The arrangement pattern of the light scattering members 10 in the light scattering region 4 is configured to match the light intensity distribution pattern.

  Further, as shown in FIG. 4, in the first embodiment, the arrangement pattern of the light scattering member 10 in the light scattering region 4 is kept away from the light input windows 2 a to 2 d while maintaining the above symmetry. The arrangement of the light scattering members 10 is increased. As already described, since the planar light generator according to the first embodiment uses the light input from the outside as radiated light, the input light is input through each of the light input windows 2a to 2d. After that, the light intensity is decreased by gradually diffusing. For this reason, the planar light generating device according to the first embodiment employs a configuration that increases the degree of light scattering as the distance from the light input windows 2a to 2d increases, thereby improving the uniformity of the scattering intensity.

で定義される。（１）式において、Num（r_p, P）は、基準点Ｐ（＝光散乱領域４の中心点）を中心とした光散乱領域４の周縁と内接する円の半径ｒ_mより小さな値ｒ_pを半径とした円内に存在する散乱点の数（≒光散乱部材１０の数または大きさ）である。なお、密度関数ρ（r,θ）は、厳密には散乱点に関する密度関数であるが、本実施の形態では、光散乱部材１０の数密度または存在密度と等価のものとして以下の議論を展開する。 Here, “symmetry” in the first embodiment is defined. In the first embodiment, the presence / absence of symmetry is determined by, for example, the following formula for rotational symmetry. With the center point of the light scattering region 4 as the origin, the distance from the origin as r, and the angle between any reference line passing through the origin as θ, the arrangement density function ρ (r, θ) of the light scattering member 10 is

Defined by In the equation (1), Num (r _p , P) is a value r smaller than the radius r _{m of} the circle inscribed in the periphery of the light scattering region 4 around the reference point P (= the center point of the light scattering region 4). _It is the number of scattering points existing in the circle with _p as the radius (≈the number or size of the light scattering members 10). Although the density function ρ (r, θ) is strictly a density function related to the scattering point, in the present embodiment, the following argument is developed as equivalent to the number density or existence density of the light scattering member 10. To do.

が定義される。（２）式に示すＺ（θ）について、理想的には、

を満たす場合にθｓ（≠０）の回転対称性を有することとなる。本実施の形態１では、「対称性」とは、（３）式に示す場合よりも広い概念であって、具体的には、

と定義するＴ（θ_s）に関して、Ｔ（θ_s）が極大となるθ_s（０ではない最小の数）について対称性を有するものとする。例えば、本実施の形態１では、θｓ＝９０°でＴ（θｓ）が極大となる場合には、４回対称（９０°の回転対称性、すなわちＣ₄の対称性）を有していることとし、θｓ＝１８０°でＴ（θｓ）が極大となる場合には、２回対称（１８０°の回転対称性、すなわちＣ₂の対称性）を有することとしている。 And, using the density function ρ (r, θ) defined by equation (1),

Is defined. For Z (θ) shown in equation (2), ideally,

When satisfying the above, it has rotational symmetry of θs (≠ 0). In the first embodiment, “symmetry” is a broader concept than the case shown in the equation (3). Specifically,

Suppose that T (θ _s ) defined as follows has symmetry with respect to θ _s (minimum number that is not 0) where T (θ _s ) is a maximum. For example, in Embodiment 1, when θs = 90 ° and T (θs) is maximized, it has four-fold symmetry (90 ° rotational symmetry, that is, C ₄ symmetry). When θs = 180 ° and T (θs) becomes a maximum, it has two-fold symmetry (180 ° rotational symmetry, that is, C ₂ symmetry).

  It should be noted that symmetry other than the case of rotational symmetry, for example, axial symmetry, can be similarly defined. For example, in the case of axial symmetry, symmetry can be defined almost similarly by converting the variables θ and r in the equations (1) to (4) into appropriate variables. In addition, the axial symmetry and the like are also symmetric not only in the ideal case corresponding to the expression (3) but also in the case of having a maximum value in the correlation corresponding to the expression (4) in the first embodiment. Treat as.

  Next, advantages of the planar light generator 1 according to the first embodiment will be described. FIG. 5A is a graph showing the result of numerical calculation of the intensity distribution of the planar light output from the planar light generator having the arrangement pattern of the light scattering member 10 shown in FIG. That is, FIG. 4 is a graph showing the distribution of light intensity output from each lattice point by dividing the light output surface of the planar light generator into a large number of lattice points. FIG. 5B is a graph showing the result of numerical calculation of the intensity distribution of the planar light in the planar light generating device having the conventional structure under the same measurement conditions as FIG. 5-1. In addition, the planar light generating device having a conventional structure is arranged uniformly in the light scattering region without regard to the symmetry of the arrangement pattern of the light scattering members. In the graphs shown in FIGS. 5A and 5B, the horizontal axis represents the light intensity, and the vertical axis represents the number of lattice points.

  As apparent from the graph shown in FIG. 5A, the intensity distribution of the planar light output from the planar light generating apparatus according to the first embodiment has a maximum number of lattice points at a certain intensity, The grid points are distributed so as to have an intensity in the vicinity of the intensity. This indicates that most of the lattice points on the light output surface of the planar light generator have substantially the same light intensity. In other words, almost uniform light is output on most of the light output surface. It means that That is, it is clear from the graph of FIG. 5A that the planar light generator 1 according to the first embodiment outputs planar light with uniform intensity. On the other hand, as shown in FIG. 5B, in the conventional planar light generator, the number of lattice points is distributed almost uniformly over all the intensities. Therefore, in the conventional planar light generator, planar light with various intensities is output from the light output surface, and it is difficult to output planar light with uniform intensity.

  The difference between the planar light generator according to the first embodiment and the conventional planar light generator can be found in the arrangement pattern of the light scattering members as described above. That is, while the conventional planar light generation device does not have a significant symmetry in the arrangement pattern of the light scattering members, the planar light generation device 1 according to the first exemplary embodiment has the intensity of input light in free space. The light scattering member 10 is arranged so as to have symmetry that matches the symmetry of the distribution pattern. Therefore, the planar light generating device according to the first embodiment arranges the light scattering member 10 so as to have a symmetry that coincides with the symmetry of the intensity distribution pattern of the input light in the free space, thereby providing a light output surface. It is considered that it is possible to output planar light having uniform intensity throughout.

(Modification 1)
Next, a first modification of the planar light generator according to the first embodiment will be described. FIG. 6 is a plan view showing the structure of the planar light generator according to the first modification. As shown in FIG. 6, the planar light generator 11 according to the first modification is formed so that the light scattering region has a rectangular shape. In addition, light input windows 12a to 12d are formed in regions corresponding to the vertices of the rectangle, and radiated light is input from the point light sources 5a to 5d arranged outside through the light input windows 12a to 12d. Also, the light input windows 12a to 12d are predetermined corrections that appropriately correct the light intensity distribution in the free space so that the light intensity distribution in the free space becomes C _2V symmetry in the Shane-Fries symbol for the light input through the light input windows 12a to 12d, respectively. Has a correction function. Specifically, for example, the light input windows 12a to 12d have a direction in which the light input through the light input windows 12a to 12d is directed to the center point of the light scattering region 14 for each of the point light sources 5a to 5d. Each axis has a function of correcting the light intensity distribution so as to have the same symmetry. Further, the planar light generating device 11 according to the first modification includes a light scattering region 14 on the bottom surface inside as in the first embodiment, and a large number of light scattering members 10 are disposed on the light scattering region 14. Has a structure.

In the first modification, the light scattering member 10 is arranged to have the same symmetry as the intensity distribution pattern in the free space of the input light, as in the case of the embodiment. That is, in the planar light generating device 11 according to the first modification, the light scattering member 10 is arranged such that the arrangement pattern has C _2V symmetry in the Shane-Fleece symbol. By having such a configuration, the planar light generation device 11 according to the first modification can output uniform planar light as in the first embodiment.

(Modification 2)
Next, a second modification of the planar light generator according to the first embodiment will be described. FIG. 7 is a plan view showing the configuration of the planar light generator according to the second modification. As shown in FIG. 7, in the planar light generating device according to the second modification, the shape of the light scattering region 18 included in the planar light generating device 15 is a rectangular shape, and at a position corresponding to the vertex of the rectangular shape. The light input windows 16a to 16d have the same configuration as that of the first modification in that the light input windows 16a to 16d are formed. On the other hand, in the second modification, the structure of the light input windows 16a to 16d and the arrangement mode of the point light sources 5a to 5d have different configurations from the first modification.

Specifically, as shown in FIG. 7, the central axis of the light output from the point light sources 5 a to 5 d and passing through the light input windows 16 a to 16 d is clockwise with respect to the central point of the light scattering region 18. The structure of the light input windows 16a to 16d and the arrangement of the point light sources 5a to 5d are devised so as to be shifted by an angle θ. Therefore, in the planar light generating device according to the second modification, the intensity distribution in the free space of the radiated light input through the light input windows 16a to 16d does not have C _2V symmetry as a whole. It simply has two-fold symmetry (180 ° rotational symmetry, ie C ₂ symmetry).

  Even in the case where the intensity distribution of the input light in the free space is symmetric twice as in the case of the second modification, uniform planar light can be output. That is, in the light scattering region 18, by arranging the light scattering member 10 so as to match the symmetry of the input light, specifically, the light scattering member 10 has two-fold symmetry with respect to the center point of the light scattering region 18. By arranging so that uniform planar light can be output.

(Modification 3)
Next, a third modification of the planar light generating device according to the first embodiment will be described. FIG. 8 is a plan view showing the overall configuration of the planar light generator according to the third modification. As shown in FIG. 8, the planar light generator 19 according to the third modification has the same structure as that of the first embodiment in that the light scattering region 20 has a square shape, while the light input window is This is different from the first embodiment in that it is provided not only in the area corresponding to the apex of the square but also in the area corresponding to the midpoint of each side.

That is, the planar light generating device 19 according to the third modification has a light input to the area corresponding to the midpoint of each side of the square in addition to the light input windows 2a to 2d provided in the area corresponding to the apex of the square. It has a structure in which windows 2e to 2h are formed. And it has the structure into which the radiated light from the point light sources 5e-5h is input via this light input window 2e-2h. The light input windows 2e to 2h are configured to correct the light traveling direction and the like so that the intensity distribution of the radiated light from the point light sources 5e to 5h has C _4V symmetry in free space, if necessary. Yes.

As shown in the third modification, the planar light generating device having a rectangular light scattering region also adopts a configuration in which light is input from a region other than the region corresponding to the rectangular vertex. It is possible to output planar light with uniform intensity in the same manner as described above. That is, by arranging the light scattering member 10 so as to have symmetry that matches the symmetry of the intensity distribution in the free space of the input light, it is possible to output planar light with uniform intensity. Specifically, in the configuration shown in FIG. 8, it is possible to output planar light with uniform intensity by disposing the light scattering member 10 on the light scattering region 20 so as to have C _4V symmetry. It is.

  This is particularly effective in a planar light generator that generates planar light based on light from a point light source such as an LED. In other words, point light sources such as LEDs tend to have a lower light intensity than line light sources such as fluorescent tubes, and so when configured to input light from a point light source only through a region corresponding to the vertex. In some cases, the amount of light may become insufficient as the area of the planar light output surface increases. However, as shown in the third modification, even when a configuration in which light from a point light source is input through a region other than the vertex is taken into consideration, the symmetry of the arrangement pattern of the light scattering members is taken into consideration. Thus, uniform planar light can be output. Therefore, the planar light generator according to the third modification also has an advantage that the planar light generator that generates planar light using light from a point light source can be enlarged.

(Embodiment 2)
Next, an image display apparatus according to the second embodiment will be described. The image display apparatus according to the second embodiment has a configuration in which the planar light generator according to the first embodiment is used as a backlight.

  FIG. 9 is a schematic diagram showing the overall configuration of the image display apparatus according to the present embodiment. In FIG. 9, the array substrate 21 is displayed in a state separated from other components, but this is displayed for convenience in order to facilitate understanding of the surface structure of the array substrate 21. In an actual image display device, the array substrate 21 and the alignment film 25a are in close contact with each other.

  As shown in FIG. 9, the image display apparatus according to the second embodiment includes an array substrate 21 on which a predetermined circuit structure is formed, a counter substrate 22 disposed to face the array substrate 21, and an array substrate 21. And a liquid crystal layer 23 sealed between the counter substrate 22 and the counter substrate 22. More specifically, an alignment film 25 a is formed on the array substrate 21, and an alignment film 25 b is formed on the lower surface of the counter substrate 22. The alignment films 25 a and 25 b are in direct contact with the liquid crystal layer 23. Further, polarizing plates 26 a and 26 b are arranged on the outer surface of the array substrate 21 and the outer surface of the counter substrate 22, respectively. A backlight 32 that outputs planar light to the array substrate 21 is disposed below the array substrate 21.

  The array substrate 21 and the counter substrate 22 are each formed using a transparent plastic substrate having excellent light transmittance or non-alkali glass as a base material, and has a structure with excellent surface flatness. Although not shown, in the case of an image display device that performs color display, a configuration is adopted in which color filters having light transmission characteristics corresponding to R, G, and B are arranged on the inner surface or outer surface of the counter substrate. Is normal.

  The liquid crystal layer 23 is formed mainly of liquid crystal molecules having orientation. The liquid crystal molecules contained in the liquid crystal layer 23 may be any liquid crystal molecules that can be generally used for an image display device using liquid crystal, and the liquid crystal molecules are not particularly limited.

  The alignment films 25 a and 25 b are for defining the alignment direction of the liquid crystal molecules contained in the liquid crystal layer 23. Specifically, the alignment films 25a and 25b each have a structure in which the surface in contact with the liquid crystal layer 23 has anisotropy, and the alignment directions of the liquid crystal molecules in the vicinity of the alignment films 25a and 25b according to the anisotropic structure. Is defined.

  The polarizing plates 26a and 26b have a structure provided with a transmission axis that allows only polarized components in a predetermined direction to pass through in the input light. Based on the optical correlation between the orientation direction of the liquid crystal molecules contained in the liquid crystal layer 23 and the polarizing plates 26a and 26b, the light transmittance of each pixel circuit 27 to be described later is controlled to display an image. It has been broken.

  Next, the circuit structure formed on the array substrate 21 will be described. As shown in FIG. 9, on the array substrate 21, a plurality of pixel circuits 27 corresponding to display pixels are arranged in a matrix. Further, a plurality of scanning lines 28 that supply a predetermined scanning signal to the pixel circuit 27 and a row direction of the matrix formed by the pixel circuit 27 are extended in the column direction of the matrix formed by the pixel circuit 27. Then, a plurality of signal lines 29 for supplying a display signal corresponding to the display gradation to the pixel circuit 27, a scanning line driving circuit 30 for generating a scanning signal for selecting the pixel circuit 27, and a display signal are generated. And a signal line driving circuit 31. A pixel electrode (not shown) that accumulates charges corresponding to the display gradation is disposed in the pixel circuit 27, and charges are accumulated in the pixel electrodes by appropriately changing the potentials of the scanning lines 28 and the signal lines 29. It has a configuration.

  The backlight 32 is for outputting planar light to the liquid crystal layer 23. The liquid crystal layer 23 is applied with an electric field corresponding to the display gradation by the pixel electrode provided in the pixel circuit 27 formed corresponding to the display pixel on the array substrate 21, and the orientation of the liquid crystal molecules contained in the liquid crystal layer 23. Changes. The light transmittance of the liquid crystal layer 23 becomes a value corresponding to the display gradation by the change in the orientation of the liquid crystal molecules and the function of the polarizing plates 26a and 26b. Then, when the backlight 32 outputs planar light to the liquid crystal layer 23 in such a state, the light that has passed through the liquid crystal layer 23 has light and shade according to the display image, and image display is performed.

  In the image display apparatus according to the second embodiment, the planar light generator according to the first embodiment is used as the backlight 32. As already described, the planar light generator according to the first embodiment has a configuration that outputs uniform planar light while using a point light source as input light. Therefore, the image display apparatus according to the second embodiment has an advantage that uniform image display is possible while enjoying the advantages of the point light source of low power consumption and high durability.

1 is a plan view showing an overall configuration of a planar light generator according to a first embodiment. It is sectional drawing in the AA of FIG. It is a three-dimensional view showing the shape of the light scattering member. It is a three-dimensional view showing the shape of the light scattering member. It is a three-dimensional view showing the shape of the light scattering member. It is a schematic diagram which shows the arrangement pattern of the light-scattering member in a light-scattering area | region. 3 is a schematic graph showing an intensity distribution of light output from the planar light generator according to the first embodiment. It is a typical graph which shows intensity distribution of the light output from the planar light generator of the conventional structure. It is a top view which shows the structure of the planar light generator concerning the modification 1. It is a top view which shows the structure of the planar light generator concerning the modification 2. It is a top view which shows the structure of the planar light generator concerning the modification 3. FIG. 3 is a schematic diagram illustrating an overall configuration of an image display apparatus according to a second embodiment. It is a schematic diagram which shows the structure of the conventional planar light generator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Planar light generator 2a-2h Light input window 3 Light guide member 4 Light scattering area 5a-5h Point light source 7 Reflective member 10a-10c Light scattering member 11 Planar light generator 12a-12d Light input window 13 Light guide member DESCRIPTION OF SYMBOLS 14 Light-scattering area | region 15 Planar light generator 16a-16d Light input window 18 Light-scattering area 19 Planar light generator 20 Light-scattering area 21 Array substrate 22 Opposite substrate 23 Liquid crystal layer 25a, 25b Alignment film | membrane 26a, 26b Polarizing plate 27 Pixel circuit 28 Scan line 29 Signal line 30 Scan line drive circuit 31 Signal line drive circuit 32 Backlight 101 Point light source 102 Light guide

Claims (8)

A plurality of point light sources for emitting an input light radially, a planar light generating device including a light scattering means for generating a planar light by causing disturb diffusing the input light,
A plurality of light input windows formed corresponding to the plurality of point light sources ;
The light scattering as the symmetry of the arrangement pattern of symmetry and before Symbol light scattering means of the intensity distribution pattern in free space of the input light from the plurality of point light sources which is input through the optical input window matches A light guide means having a light scattering region in which the means is disposed;
Equipped with a,
Each of the input lights is input to the light guide means from a direction perpendicular to the emission direction of the planar light ,
Each of the optical axes of the input light is deviated by a predetermined angle in the same rotation direction with respect to a straight line passing through the point light source and the center point of the light diffusion region on a plane perpendicular to the emission direction of the planar light . A planar light generator characterized by the above. A plurality of point light sources for emitting an input light radially, a planar light generating device including a light scattering means for generating a planar light by causing disturb diffusing the input light,
A plurality of light input windows formed corresponding to the plurality of point light sources and having a function of adjusting an intensity distribution pattern in free space of input light from each point light source ;
The light scattering as the symmetry of the arrangement pattern of symmetry and before Symbol light scattering means of the intensity distribution pattern in free space of the input light from the plurality of point light sources which is input through the optical input window matches A light guide means having a light scattering region in which the means is disposed;
A planar light generator characterized by comprising: The light scattering region, the shape of the emission direction perpendicular to the cross section of the planar light is rectangular,
The light input window, planar light generating apparatus according to claim 1 or 2, characterized in that it is formed at a position corresponding to the vertex of the rectangle. The intensity distribution pattern of the input light in free space is symmetric twice with respect to a reference point in the light scattering region;
4. The planar light generator according to claim 3 , wherein the light scattering means is arranged so as to be symmetrical twice with respect to the reference point. The intensity distribution pattern of the input light in free space has C _2V symmetry,
4. The planar light generator according to claim 3 , wherein the light scattering means is disposed on the light scattering region so as to have _C2V symmetry. The light scattering region is a cross-sectional shape perpendicular and emission direction of the planar light is square,
The input light is input through the light input window formed corresponding to each vertex of the square ,
Intensity distribution pattern in free space of the entering force light has a symmetry C _4V,
It said light scattering means, the planar light generating apparatus according to claim 3, characterized in that it is arranged to have symmetry C _4V in the light scattering region. An array substrate on which pixel circuits corresponding to display pixels are formed;
A counter substrate disposed to face the array substrate;
A liquid crystal layer sealed between the array substrate and the counter substrate;
A plurality of point light sources for emitting input light radially; a light scattering means for generating planar light by scattering the input light ; and a plurality of light input windows formed corresponding to the plurality of point light sources; said light scattering means is arranged so that the symmetry of the arrangement pattern of the plurality of the light scattering means and symmetry of the intensity distribution pattern in free space of the input light inputted through the light input window matches A planar light generating means having a light guide means having a light scattering region ;
Equipped with a,
The input light is input to the light guide means from a direction perpendicular to the emission direction of the planar light,
The image is characterized in that the optical axis of the input light is off by a predetermined angle with respect to a straight line passing through the point light source and the center point of the light diffusion region in a plane perpendicular to the emission direction of the planar light. Display device. An array substrate on which pixel circuits corresponding to display pixels are formed;
A counter substrate disposed to face the array substrate;
A liquid crystal layer sealed between the array substrate and the counter substrate;
A plurality of point light sources for emitting input light radially, a light scattering means for generating planar light by scattering the input light, and input light from each point light source formed corresponding to the plurality of point light sources a plurality of light input window having a function of adjusting the intensity distribution pattern in the free space, and the symmetry of the intensity distribution pattern in free space of the input light from the plurality of point light sources which is input through the optical input window A planar light generating means having a light guide means having a light scattering region in which the light scattering means is arranged so that the symmetry of the arrangement pattern of the light scattering means is matched ;
An image display device comprising:

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