JP5375210B2 - LIGHTING DEVICE, ELECTRO-OPTICAL DEVICE AND ELECTRONIC DEVICE HAVING THE LIGHTING DEVICE - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting device which can attain both reduction of luminance unevenness and thinning. <P>SOLUTION: A concave mirror 41 arranged on every partitioned zone d has a curvature which can make light incident from a point light source 30 at a shape similar to a rectangle of the partitioned zone. The lighting device 50 is provided with a sealing substrate 27, the point light source 30, a transparent substrate 25, and the concave mirror 41 in order from a light-emitting face S side, and the point light source 30 is arranged in the vicinity of the focal point of the concave mirror 41 by adjusting thickness of the transparent substrate 25 with an adjustment substrate 22. Further, thickness of the transparent substrate 25 is established so as to make an angle between a line segment for connecting the point light source 30 and one side of an outline of the concave mirror 41 and a perpendicular line passing through the point light source approximately coincide with a critical angle of the transparent substrate 25 between it and an air layer e. Thus, independent luminance control for each partitioned zone d can be attained in this structure. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a lighting device, and an electro-optical device and an electronic apparatus including the lighting device.

In a liquid crystal display device using a liquid crystal as an electro-optical material, the liquid crystal itself does not emit light, so that display is performed using external light or light emitted from an external illumination device. For example, a transmissive liquid crystal display device includes an illumination device (backlight) that irradiates a liquid crystal panel from the back.
Conventionally, such an illuminating device has been required to be thin and to irradiate the display area of the liquid crystal panel with uniform brightness without unevenness. In addition to these, it has also been proposed to perform partial luminance control (local dimming) in response to the recent demand for larger display panels and higher image quality.

  For example, Patent Document 1 discloses an illumination device (planar light source) that includes a plurality of point light sources arranged in a matrix and a plurality of convex lenses formed for each point light source. There is also a description that a concave mirror may be used instead of a convex lens.

JP 2002-49326 A JP 2004-126055 A

18 (a) and 18 (b) are diagrams showing illumination modes by a conventional illumination device, and are plan views of the light emitting surface viewed from the liquid crystal panel (irradiated surface) side.
As shown in FIG. 18A, in the conventional illumination device 300, the point light source 95 is arranged for each divided region d in which the light emitting surface S is divided into a lattice shape. In other words, a plurality of divided areas d are formed in a matrix, and the point light source 95 is arranged at the center of each divided area d. Note that the size of the light exit surface S substantially matches the display area V of the rectangular liquid crystal panel.
The light emitted from the point light source 95 in the divided area d is collected by the convex lens 96 arranged so as to overlap the light source, and is emitted from the light emitting surface S as a light beam Ao having a circular cross section. The light flux Ao corresponds to partial illumination light.
That is, the conventional illumination device 300 emits a light beam Ao as partial illumination light for each divided region d, and illuminates the display region V with illumination light obtained by combining the light beam Ao in a plane.

Here, as shown to Fig.18 (a), in order to irradiate the rectangular (rectangular) display area V, the light-projection surface S was also formed in the rectangle. That is, each divided region d divided into a plurality of matrix shapes is also rectangular, whereas the light beam Ao emitted from the divided region is circular, and therefore, at the four corners of each divided region d, it is outside the range of the light beam Ao. There is a problem that a low luminance region indicated by hatching is formed.
For this reason, for example, by separating the distance between the convex lens 96 and the liquid crystal panel, or changing the light condensing function of the convex lens 96, the luminous flux Ao is increased by one to overlap the luminous flux Ao. . The luminance distribution at this time is shown in FIG. 18B, and it can be seen that the low luminance region is substantially eliminated by increasing each light flux Ao.

On the other hand, overlapping the luminous flux Ao reduces the low luminance area, but on the other hand, the overlapping of the adjacent luminous fluxes Ao increases, so that there is a problem that a high luminance part occurs in the overlapping portion.
That is, the conventional illumination device 300 has a problem that uneven brightness occurs. In other words, there is a problem that it is difficult to independently control the luminance in the divided region d one by one. In addition, this problem occurs similarly when a concave mirror is used instead of the convex lens.
As a means for solving this problem, it is conceivable that the shape of the light beam Ao is rectangular according to the divided area d. For example, Patent Document 2 discloses an optical system for converting a light beam having a circular cross section into a light beam having a rectangular cross section.

However, in the optical system of Patent Document 2, two lenses including a collimator lens are required to convert a light beam having a circular cross section into a light beam having a rectangular cross section. Further, there is a description that the optical action of the two lenses can be realized by one lens, but no specific description is found.
As described above, the illuminating device is required to be thin, and it is extremely difficult to reduce the thickness with a configuration in which two lenses are provided between the point light source and the display area (liquid crystal panel). It was.
Thus, the conventional lighting device has a problem that it is difficult to achieve both reduction in luminance unevenness and reduction in thickness. In other words, there has been a problem that there has been no illumination device having a thickness that allows independent brightness control for each divided region and that can be used as a backlight of a liquid crystal display device.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following application examples or forms.

(Application example)
A light emitting surface composed of a plurality of divided regions having a substantially rectangular shape is provided, and the divided regions have a point light source and a point light source side corresponding to the point light source in the depth direction from the light emitting surface. The concave mirror reflects the light emitted from the point light source as partial illumination light to the point light source side, and the concave surface of the concave mirror corresponds to each rectangular side of the divided area. An illumination device characterized in that illumination light, which has a curvature in the depth direction from each of the parts and which is obtained by planarly combining partial illumination light emitted from a plurality of divided regions, is emitted from a light emission surface.

According to this illuminating device, the surface of the concave part of the concave mirror has a curvature in the depth direction from each part corresponding to each side of the rectangle of the divided area.
For example, in a plan view, the curvature radius in the extending direction of a line segment that passes through the point light source and is substantially orthogonal to one side of the rectangle of the divided region is larger than the curvature radius in the extending direction of the diagonal line in the rectangle. By setting the curvature to be small, the shape of the light reflected by the concave mirror can be made similar to the rectangular shape of the divided area.
Therefore, according to the illumination device according to the application example, the portion on the light exit surface is different from the conventional illumination device in which the luminance unevenness occurs due to the difference between the shape of the irradiation region and the shape of the divided region. It is possible to make the size of the illumination light substantially coincide with the size of the divided area.
Therefore, luminance unevenness can be reduced as compared with the conventional lighting device.
Furthermore, unlike a conventional illumination device that requires two lenses to emit rectangular light, according to the illumination device according to the application example, a single concave mirror provided for each divided region provides a rectangular cross section. The partial illumination light having a shape can be emitted.
Therefore, it can be configured to be thinner than the conventional lighting device.
Therefore, it is possible to provide an illumination device that achieves both reduction in luminance unevenness and reduction in thickness.

Further, each of the point light sources is disposed on the transparent substrate so as to be positioned approximately at the center of the rectangle of the divided region in plan view, and each of the concave mirrors having substantially the same outer shape as the rectangle of the divided region in plan view, It is formed on the mirror array substrate, and in the depth direction from the light emitting surface, the transparent substrate and the mirror array substrate are stacked in this order, and formed between the transparent substrate and the concave mirror of the mirror array substrate. An air layer is formed in the space, and in a cross-sectional view, the angle between the perpendicular from the light exit surface passing through the point light source and the line segment connecting the point light source and one side of the outer shape of the concave mirror is the air layer. It is preferable that the thickness of the transparent substrate is set so as to substantially coincide with the critical angle of the transparent substrate.
In addition, the concave mirror has a curvature such that, in plan view, the radius of curvature in the extending direction of the line segment passing through the point light source and substantially orthogonal to one side of the rectangle is smaller than the radius of curvature in the extending direction of the diagonal line. It is preferable.

The outer peripheral edge of the concave mirror in the mirror array substrate is provided with a light-shielding portion, and the light-shielding portion has a lattice shape so as to partition a plurality of concave mirrors in a plan view and a transparent substrate in a cross-sectional view. It is preferably sandwiched between the mirror array substrate.
The point light source is an EL element or an LED element, and is laminated on the transparent substrate in the order of the first transparent electrode, the point light source, the metal electrode, and the second transparent electrode. It is preferable that it is formed only in a portion overlapping with the light source and is electrically connected to the second transparent electrode.

  A light emitting surface composed of a plurality of divided regions each having a substantially rectangular shape, and a convex lens having a convex portion on the surface on the light emitting surface side and a light emitting surface of the convex lens corresponding to the convex lens. A point light source disposed on the side opposite to the side, and the convex lens expands the light emitted from the point light source and emits it as partial illumination light, and the convex lens surface of the convex lens Projecting with a curvature from each part corresponding to each side of the rectangle, and emitting illumination light, which is a planar synthesis of partial illumination light emitted from a plurality of divided areas, from the light exit surface Lighting device.

  Further, each of the point light sources is arranged on the transparent substrate so as to be positioned substantially at the center of the rectangle of the divided area in plan view, and each of the convex lenses having the same outline as the rectangle of the divided area in plan view. Is formed on the lens array substrate, and in the depth direction from the light exit surface, the lens array substrate and the transparent substrate are stacked in this order via an air layer, and a point light source on the transparent substrate is arranged When the surface to be processed is the first surface and the surface opposite to the first surface is the second surface, the perpendicular from the first surface passing through the point light source, the point light source and the second surface in the cross-sectional view The thickness of the transparent substrate should be set so that the angle with the line segment connecting one side of the outer shape of the convex lens projected onto the surface substantially matches the critical angle of the transparent substrate with the air layer. preferable.

Further, the convex lens has a curvature such that, in plan view, the radius of curvature in the extending direction of the line segment passing through the point light source and substantially orthogonal to one side of the rectangle is smaller than the radius of curvature in the extending direction of the rectangular diagonal line. It is preferable to have.
The air layer is formed by a light-shielding portion disposed between the lens array substrate and the second surface of the transparent substrate, and the light-shielding portion forms a lattice shape along the rectangle of the divided region in plan view. Preferably it is.
One point light source is preferably an aggregate of a plurality of element light sources including red, blue, and green.
Further, the light exit surface is divided substantially evenly by divided regions having substantially the same size, and the rectangle is preferably a square.

The illuminating device described above and a transmissive or transflective display panel having a rectangular display region, and the rear surface of the display region and the light emitting surface of the illuminator face each other, An electro-optical device, wherein a display panel and an illumination device are arranged to overlap each other.
In addition, the display area is formed from a large number of pixels, and one divided area on the light exit surface is formed to be approximately the same size as a pixel area composed of a plurality of pixels among the large number of pixels. Is preferred.
The display panel is preferably a liquid crystal panel.

  An electronic apparatus comprising the electro-optical device described above as a display unit.

1 is a perspective view illustrating a schematic configuration of a liquid crystal display device according to Embodiment 1. FIG. FIG. 2 is a side sectional view of the liquid crystal display device taken along a q-q section in FIG. 1. The exploded perspective view of an illuminating device. The circuit block diagram of a point light source. (A) The top view which shows the wiring aspect of a point light source, (b) is sectional drawing in the uu cross section of the same figure (a). The sectional side view of an illuminating device. (A)-(c) Explanatory drawing of the curvature of a concave mirror. The top view which shows the illumination aspect by an illuminating device. FIG. 6 is a side sectional view of a liquid crystal display device according to a second embodiment. The exploded perspective view of an illuminating device. The sectional side view of an illuminating device. (A)-(c) Explanatory drawing of the curvature of a convex lens. The circuit block diagram of a point light source. Sectional drawing of a point light source vicinity. The figure which shows the multimedia player as an electronic device. FIG. 10 is a side sectional view of a liquid crystal display device according to Modification Example 1. The plane aspect figure of the point light source which concerns on the modification 2. FIG. (A), (b) The illumination mode figure by the conventional illuminating device.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the scales are different for each layer and each member so that each layer and each member can be recognized on the drawing.

(Embodiment 1)
"Schematic configuration of liquid crystal display"
FIG. 1 is a perspective view showing a schematic configuration of the liquid crystal display device according to the present embodiment.
First, a schematic configuration of a liquid crystal display device 100 as an electro-optical device according to Embodiment 1 of the present invention will be described with reference to FIG.

The liquid crystal display device 100 includes a display panel 10, an illumination device 50, and the like.
The display panel 10 is a transmissive liquid crystal panel in which liquid crystal as an electro-optical layer is sandwiched between two transparent substrates. A rectangular display region V is formed on the front surface side of the display panel 10, and an illumination device 50 is provided as a backlight on the back surface side. In FIG. 1, the display panel 10 and the illumination device 50 are drawn away from each other in order to make the configuration easy to understand. In addition, an optical film such as a diffusion plate is disposed between them, but is omitted in FIG.
The display panel 10 may be a display panel that performs display in the display area V on the front surface using light incident from the back side. For example, the display panel 10 may be a transflective liquid crystal panel.

The display area V is a rectangular area composed of a plurality of pixels P.
As shown in the f part (drawing surrounded by a circle on the upper right in FIG. 1) which is an enlarged view of a part of the display area, each pixel P has a rectangular shape, and its width (short side) is height (long side). ). Here, the pixel array arranged in the short side direction is referred to as a pixel row, and the pixel array arranged in the long side is referred to as a pixel column.
In the pixel row, a red pixel Pr, a green pixel Pg, and a blue pixel Pb are arranged in this order and periodically. In the pixel column, the color tone pixels in the uppermost pixel row are continuously arranged. Further, one color pixel Pc is formed by three pixels Pr, Pg, and Pb that are continuous in the pixel row. Note that the pixel Pr, the pixel Pg, and the pixel Pb may be read as sub-pixels, and the pixel Pc as a pixel.
In each drawing including FIG. 1, the extending direction of the pixel row is taken as the X axis, and the extending direction of the pixel column is taken as the Y axis. Moreover, the perpendicular direction from the plane including the X axis and the Y axis, in other words, the thickness direction of the display panel 10 (illuminating device 50) is defined as the Z axis.

The illumination device 50 is a plate-like surface light source, and includes a light emitting surface S having a rectangular shape on a surface facing the display panel 10. The light exit surface S is set to a size that is substantially the same as the projected size of the display area V of the display panel 10. In other words, the light exit surface S is disposed so as to overlap the back side of the display region V, and the size thereof is substantially the same as that of the display region V. In consideration of the combination accuracy of the display panel 10 and the lighting device 50 at the time of manufacture, it is preferable that the light exit surface S is slightly larger than the display region V.
Here, the light emission surface S is composed of a plurality of divided regions d having a substantially rectangular shape. In other words, the light emitting surface S is divided into a plurality of divided regions d.
The light emission surface S is substantially equally divided by a plurality of divided regions d having substantially the same size. One divided area has a substantially square shape, and the size thereof is substantially the same as a pixel area composed of a plurality of color pixels Pc. In other words, the pixel area composed of a plurality of color pixels Pc is illuminated by one divided area d. Note that the size of the divided region d is appropriately set in consideration of the size and resolution of the display panel 10, the total thickness of the liquid crystal display device 100, and the like.

"Configuration of the lighting device"
FIG. 2 is a side sectional view of the liquid crystal display device taken along a qq section in FIG. 1. FIG. 3 is an exploded perspective view of the lighting device.
Next, a detailed configuration of the lighting device 50 will be described with reference to FIGS. 2 and 3.

As shown in FIG. 2, the diffusion plate 15 and the illumination device 50 are arranged in this order on the back side (Z-axis (+) side) of the display panel 10 in this order. This stacking direction (Z-axis (+) direction) is also referred to as a depth direction. Note that polarizing plates are provided on the front and back surfaces of the display panel 10 and optical films such as a retardation plate and a prism sheet are further laminated depending on the specifications, but are omitted in FIG.
The diffusing plate 15 is, for example, a translucent resin sheet coated with a resin (a diffusing member) that diffuses light. The diffusing plate 15 scatters and diffuses the illumination light emitted from the light emitting surface S and emits it to the display region V.

As shown in FIG. 3, the illumination device 50 includes a transparent substrate 25 on which a plurality of point light sources 30 are formed, a mirror array substrate 40, and the like.
The plurality of point light sources 30 are arranged in correspondence with each of the divided regions d divided in a matrix on the transparent substrate 25, and a sealing substrate 27 is formed on the upper layer. The point light source 30 may be a light emitting element such as an LED (Light Emitting Diode) element, an inorganic EL (Electro Luminescence) element, or an organic EL element. Note that the point light source 30 includes a configuration in which, for example, an assembly of minute red, green, and blue light emitting elements is regarded as a point light source that emits one white light. As an example, an organic EL element that emits white light is employed.
The sealing substrate 27 is formed so as to cover the plurality of point light sources 30 in order to protect the organic EL element that deteriorates due to moisture, and the surface of the substrate is a light emitting surface S.
On the surface of the mirror array substrate 40 on the transparent substrate 25 side (Z-axis (−) side), a plurality of concave mirrors 41 recessed from the surface are formed one by one for each divided region d. In plan view, each concave mirror 41 is laid out so as to form a substantially square shape along the divided region d and to have a point light source 30 corresponding to the center thereof.

Returning to FIG.
As described above, the illumination device 50 is configured in the order of the sealing substrate 27, the point light source 30, the transparent substrate 25, and the mirror array substrate 40 in the depth direction from the light emitting surface S side.
Here, the transparent substrate 25 is formed by bonding the element substrate 20 and the adjustment substrate 22 together. This is to ensure the focal length between the point light source 30 and the concave mirror 41, and a detailed dimensional relationship will be described later. However, the thickness adjustment is performed on the element substrate 20 on which the point light source 30 is formed. The adjustment substrate 22 is bonded with, for example, an adhesive sheet using an acrylic pressure-sensitive adhesive.
Since the point light source 30 and the wiring layer are formed on the element substrate 20 using a photolithography method and various processes including heat treatment, an alkali component is included in order to prevent the influence on those processes. There is no alkali-free glass.
In addition, since a functional layer such as the point light source 30 is not formed on the adjustment substrate 22, inexpensive soda glass having substantially the same refractive index as that of non-alkali glass is used.
Note that the refractive index of the adhesive sheet for bonding the element substrate 20 and the adjustment substrate 22 is substantially the same as the refractive index of the both, so that the transparent substrate 25 bonded together is one sheet having substantially uniform optical characteristics. It can be regarded as a glass substrate.

A metal electrode 31 as a cathode is formed on the sealing substrate 27 side (Z-axis (−) side) of the point light source 30 formed on the element substrate 20. Here, since the metal electrode 31 is made of, for example, a metal such as an alloy of Mg and Ag, the light emitted from the point light source 30 toward the sealing substrate 27 is the metal electrode 31. Only the light that is blocked by and directed toward the concave mirror 41 is utilized.
The adhesive layer 28 is a barrier / adhesive layer including a barrier layer made of a SiO ₂ film, a transparent resin layer such as an acrylic resin layer, etc., and prevents moisture from entering the point light source 30 and The sealing substrate 27 is bonded. In addition, since the refractive index of these each part is also substantially equivalent to the refractive index of glass, the transparent substrate 25 including the sealing substrate 27 can be regarded as an integral glass member having substantially uniform optical characteristics.

On the mirror array substrate 40, a concave mirror 41 is formed for each divided region d. The mirror array substrate 40 is obtained, for example, by molding a resin substrate having a plurality of concave shapes by an injection molding method and then depositing a reflective film such as aluminum or chromium by an evaporation method. Further, the present invention is not limited to the vapor deposition method, and it is sufficient that a reflective film can be formed on the resin substrate. For example, a manufacturing method using a chemical plating method may be used. Alternatively, the concave mirror 41 may be formed by pressing a reflective metal plate.
Here, the concave mirror 41 reflects the light emitted from the corresponding point light source 30 toward the point light source 30 and has a curvature for making the cross section of the light beam of the reflected light similar to the square of the divided region d. have. Details of the curvature will be described later.
Thereby, as indicated by an arrow, the reflected light reflected by the concave mirror 41 (hereinafter also referred to as “partial illumination light”) has a square section substantially the same as that of the substantially divided region d on the light exit surface S. It becomes a luminous flux. Note that an air layer e is formed between the transparent substrate 25 and the concave portion of the concave mirror 41, and as indicated by an arrow, the curvature of the concave mirror 41 is a refractive action due to a difference in refractive index between the transparent substrate 25 and the air layer e. The curvature incorporates.

As described above, since the partial illumination light reflected by the concave mirror 41 is emitted toward the point light source 30, the portion overlapping the point light source 30, that is, the portion overlapping the metal electrode 31 receives light. Although it does not transmit, it becomes a shadow, but at the stage where it enters the display region V due to the diffusing action of the diffusing plate 15, the luminance is substantially the same as that of the peripheral part. In other words, the shadow is blurred and becomes inconspicuous. Note that the diffusion degree of the diffusion plate 15 may be changed according to the luminance distribution of the partial illumination light. Specifically, more uniform illumination is possible by changing the ratio of the diffusing member so that the degree of diffusion of the portion with high luminance is higher than that of the portion with low luminance.
Further, in order to turn on the point light source 30, a plurality of wirings including wirings connected to the metal electrode 31 are formed. However, since these wirings also affect partial illumination light, in this embodiment, The wiring mode is also devised.

"Configuration of point light source and wiring mode"
FIG. 4 is a circuit configuration diagram of a point light source. Fig.5 (a) is a top view which shows the wiring aspect of a point light source. FIG.5 (b) is sectional drawing in the uu cross section of Fig.5 (a).
Next, a circuit configuration and a wiring mode for lighting and driving the plurality of point light sources 30 will be described with reference to FIGS. 4 and 5.
As shown in FIG. 4, the plurality of point light sources 30 includes a plurality of scanning lines 34 extending from the scanning line driving circuit 32 in the X-axis direction and a plurality of scanning lines 34 extending from the data line driving circuit 33 in the Y-axis direction. It is provided at each intersection with the data line 35.
A point light source 30 made of an organic EL element is disposed between the data line 35 and the metal electrode 31. As will be described in detail later, the data line 35 that overlaps the point light source 30 functions as a pixel electrode. Further, the metal electrode 31 is connected to the corresponding scanning line 34.

The scanning line driving circuit 32 includes a shift register and an output buffer (both not shown), and sequentially supplies scanning signals to the plurality of scanning lines 34.
The data line driving circuit 33 includes a shift register and a latch circuit (both not shown), and supplies data signals to the plurality of data lines 35.
The illuminating device 50 is provided so that the brightness of the plurality of point light sources 30 can be independently controlled by a so-called simple matrix line sequential driving method. For example, when the total number of scanning lines 34 is n, the scanning line driving circuit 32 selectively drives the n scanning lines sequentially by 1 / n time by the scanning line signal in parallel. The data line drive circuit 33 supplies a data signal of a drive current (voltage) corresponding to n times the required brightness to the data line 35 on which the point light source 30 to be lit is arranged. That is, the brightness of each point light source 30 is controlled substantially independently by time-division driving (duty drive) of the plurality of point light sources 30.
Thereby, the illuminating device 50 can control the brightness | luminance of the partial illumination light in each division area d independently.

FIG. 5A is a plan view showing a wiring mode of the scanning lines 34 and the data lines 35. As described with reference to FIG. 2, since the point light source 30 is disposed on the path of the partial illumination light reflected by the concave mirror 41, the scanning line 34 and the data line 35 connected to the point light source 30 are metal wirings. In such a case, the partial illumination light is blocked and diffracted by the metal wiring.
For this reason, in this embodiment, transparent ITO (Indium Tin Oxide) is used as a wiring material for both the scanning line 34 and the data line 35.
Moreover, since ITO has a lower electrical conductivity than metal wiring, the width of each wiring is increased so as to cover the divided region d. Specifically, the scanning lines 34 are configured to be entirely covered with the wide scanning lines 34 while leaving the gap G between the scanning lines 34. Similarly, the data line 35 is configured so that the gap G between the data lines 35 is left, and the rest is entirely covered with the wide data line 35. Note that the gap G may have a dimension that is small enough to ensure electrical insulation and is not visually recognized. For example, the gap G is preferably about 3 μm to 20 μm, and more preferably about 5 μm to 10 μm. In the present embodiment, as a preferred example, the gap G is about 5 μm.
Further, instead of ITO, a transparent electrode such as ZnO (zinc oxide) may be used.

FIG. 5B is a cross-sectional view taken along the line u-u in FIG. 5A, and shows a stacking relationship between each wiring and the point light source 30.
On the element substrate 20, a scanning line 34 as a first transparent electrode, a point light source 30, a metal electrode 31, and a data line 35 as a second transparent electrode are stacked in this order. An insulating layer 37 made of, for example, SiO ₂ or acrylic resin is formed between the point light sources 30 and the adjacent point light sources 30.
Here, the part where the point light source 30 is formed on the scanning line 34, in other words, the part of the scanning line 34 that overlaps the point light source 30 functions as a pixel electrode (anode) of the point light source 30. The metal electrode 31 that functions as the cathode of the point light source 30 is electrically connected to the corresponding data line 35.

Further, the organic EL element (layer) as the point light source 30 is formed of a plurality of functional layers, although not shown.
Specifically, from the scanning line 34 side, a hole transport layer, a light emitting layer, and an electron injection layer each made of an organic thin film are stacked in this order. In this embodiment, the light emitting layer is comprised from the thin film of the organic material which can radiate | emit white light as a suitable example.
The metal electrode 31 is made of, for example, an Mg—Ag alloy (for example, a weight ratio of 10: 1).
In the present embodiment, the organic EL element (layer) as the point light source 30 is described as using a low molecular material, but a configuration using a high molecular material may be used. When a low molecular material is used, the above-described organic EL element (layer) is formed by a vacuum vapor deposition method.
In the case of using a polymer material, for example, an organic EL element (layer) is formed using an inkjet method.

"Specific optical design"
6 is a side sectional view of the lighting device, and is an enlarged view of one divided region in FIG. FIGS. 7A to 7C are explanatory views of the curvature of the concave mirror.
Here, a method for setting the thickness of the transparent substrate 25 by the adjustment substrate 22 and the method for setting the curvature of the concave mirror for disposing the point light source 30 at the substantially focal point of the concave mirror 41 will be described with reference to FIGS. To do.

FIG. 6 is a side sectional view taken along a line segment passing through the center 30c of the point light source 30 and parallel to the X axis, and a line segment passing through the center 30c and parallel to the Z axis is a center line Ce. In other words, the perpendicular from the light exit surface S passing through the point light source 30 is the center line Ce.
As shown in FIG. 6, when a dashed line connecting the center 30c of the point light source 30 and the peripheral portion of the concave mirror 41 is a line segment L1, the thickness t3 of the transparent substrate 25 is equal to the line segment L1 and the center line. The angle formed by Ce is set to a thickness that makes the angle θ.
Here, the angle θ is set to a critical angle when the light emitted from the point light source 30 enters the air layer e from the transparent substrate 25. That is, it is transparent so that the angle between the line segment L1 connecting the point light source 30 and one side of the outer shape of the concave mirror 41 and the center line Ce substantially coincides with the critical angle of the transparent substrate 25 with the air layer e. A thickness t3 of the substrate 25 is set.
Thereby, as shown by the arrow, only the light in the angle range smaller than the angle θ out of the light emitted from the point light source 30 can be emitted from the transparent substrate 25 and incident on the air layer e. On the other hand, light having an angle greater than the critical angle θ cannot exit the transparent substrate 25 and repeats total reflection within the transparent substrate 25.
In this way, the range (region) of light emitted from the transparent substrate 25 is limited. Since the divided region d is square in plan view, the same setting as in FIG. 6 is applied to the side cross section along the line segment passing through the center 30c of the point light source 30 and parallel to the Y axis. Yes. In other words, the X axis in FIG. 6 can be read as the Y axis.

Next, specific design examples will be described.
In FIG. 1, when the size of the display area V of the display panel 10 is 5 inches diagonal, the light exit surface S of the illumination device 50 is set to a size that is slightly larger than 5 inches diagonal.
Specifically, the size of the light exit surface S is set to 81.9 mm long × 107.1 mm wide so as to cover the display area V of 76.2 mm long (Y-axis direction) × 101.6 mm wide (X-axis direction). .
Then, the light exit surface S is divided into square divided regions d of about 6.3 mm square. Specifically, when the array of the divided regions d extending in the X-axis direction is a row and the array of the divided regions d extending in the Y-axis direction is a column, it is divided into 13 rows × 17 columns.
The planar size of the point light source 30 is about 0.5 mm square, and is arranged at the center of each divided region d. In other words, it arrange | positions so that the space | interval between the adjacent point light sources 30 may become about 6.3 mm space | interval in both the X-axis direction and the Y-axis direction.
That is, the light emitting surface S is divided into 13 rows × 17 columns = 221 divided regions to perform local dimming (local luminance control).

In FIG. 6, since the divided area d is about 6.3 mm square, the planar shape of the concave mirror 41 is also the same size, and the width w of the concave mirror 41 is about 6.3 mm.
Here, when the refractive index (n1) of the transparent substrate 25 is 1.52 and the refractive index (n2) of the air layer e is 1.00, the critical angle θ is about 41. 1 °.
θ = arcsin (n2 / n1) (1)
And the thickness t3 of the transparent substrate 25 is calculated | required by substituting the calculated | required critical angle (theta) and the length w / 2 of the half width w which is the length of one side of a right triangle into Formula (2). In this case, the thickness t3 is about 3.6 mm.
t3 = (w / 2) / tan θ (2)
For the element substrate 20 on which the organic EL element is formed, alkali-free glass having a thickness t1 of about 0.5 mm is generally used. Therefore, by setting the thickness t2 of the adjustment substrate 22 to about 3.1 mm, the thickness t3 (total thickness) of the transparent substrate 25 is set to about 3.6 mm.

Further, the number of divisions of the divided regions is not limited to the above numerical values, and satisfies the arithmetic expressions (1) and (2) according to specifications such as image content, resolution, and thickness of the liquid crystal display device 100. Can be set as appropriate.
For example, in the same way, in a lighting device used for a 5-inch diagonal display panel, the number of divisions may be increased in order to achieve brightness control in a finer area and further reduction in thickness.
For example, the number of divisions is 2120, which is about 10 times the above configuration.
In this case, the size of the divided region d is about 2.0 mm square, and the size of the point light source 30 is about 0.2 mm square. The size of the light emission surface S is 80.0 mm long × 106.0 mm wide, and the light emission surface S is divided into divided regions of 40 rows × 53 columns.
In the case of this division number, the thickness t3 of the transparent substrate 25 is about 1.14 mm from Equation (2), so the thickness t2 of the adjustment substrate 22 is set to about 0.64 mm.
According to this configuration, it is possible to achieve brightness control in a finer region and a reduction in thickness than the above-described configuration.

FIG. 7A is a plan view for explaining the curvature of the concave mirror 41. In the drawing, a light flux pattern having a substantially circular cross section incident from the point light source 30 is a light flux Ai (broken line). Further, a light flux pattern obtained by reflecting the light flux Ai by the concave mirror 41 is indicated by a light flux Ao (solid line). The light flux Ao is a light flux pattern of partial illumination light, and the expression partial illumination light Ao is also used in the following description.
The substantially square shape indicated by reference numeral 41 (d) indicates the outer shape (peripheral edge) of the concave mirror 41 and has the same size as the divided region d. Further, the center is set as a center point 41c. In the concave mirror 41, the curvature along the X axis passing through the center point 41c is the curvature k1. Similarly, the curvature along the Y axis passing through the center point 41c is the curvature k2. These are the reference curvatures in the horizontal and vertical directions of the concave mirror 41.
Further, the curvatures connecting the diagonal lines of the outer shape of the concave mirror 41 are the curvature k3 and the curvature k4.

FIG. 7B is a side cross-sectional view taken along the line j-j in FIG. 7A, and the curvature of the curvature k3 (k4) is also indicated by a broken line for comparison. FIG. 7C is a perspective view of the concave mirror 41.
Here, the concave mirror 41 has a curvature k1, k2 in the horizontal and vertical directions of the concave mirror 41 and a curvature in the diagonal direction in order to convert the light beam Ai having a substantially circular cross section into a light beam Ao similar to the square of the divided region d. Different from k3 and k4. In other words, the curvatures k3 and k4 in the diagonal direction are set as curvatures for extending the diagonal direction in the substantially circular light beam Ai, as indicated by arrows in FIG.
Specifically, as shown in FIG. 7B, the curvature radius of the curvature k3 (k4) is set larger than the curvature radius of the curvature k1 (k2). In addition, since the external shape of the concave mirror 41 is substantially square, the curvature k1 can be read as the curvature k2, and the curvature k3 can be read as the curvature k4. Then, as shown in FIG. 7 (c), the curvature is smoothly between the curvature k1 and the curvature k3, between the curvature k3 and the curvature k2, between the curvature k2 and the curvature k4, and between the curvature k4 and the curvature k1. Is changed to form the concave mirror 41.
Thereby, as shown in FIG. 7A, the shape of the light beam Ao reflected by the concave mirror 41 becomes a substantially square shape similar to the shape of the divided region d. Further, the concave mirror 41 is arranged so that its size is slightly larger than that of the divided region d.

FIG. 8 is a plan view showing an illumination mode by the illumination device of the present embodiment, and corresponds to FIG. The drawing shows a state in which the light exit surface S is viewed from the display panel 10 side (Z-axis (−) side).
As shown in FIG. 8, from the light emitting surface S, the rectangular partial illumination light Ao emitted from each of the plurality of divided regions d is synthesized in a plane without substantial gaps and without large overlap. The light exit surface S is emitted as substantially uniform illumination light.

Returning to FIG.
In the liquid crystal display device 100, the lighting mode of the lighting device 50 described above is controlled in conjunction with the display image on the display panel 10.
Specifically, the brightness of the partial illumination light emitted from the divided region d is adjusted in units of the divided region d in accordance with the luminance distribution of the display image per frame. In other words, the brightness of the partial illumination light is dynamically controlled in terms of location and time in conjunction with the luminance change of the display image.
In addition, a light sensor such as a photodiode that detects the ambient brightness may be provided on the display panel 10, and the brightness of the illumination light may be adjusted according to the ambient brightness.
That is, the liquid crystal display device 100 performs a local dimming method in which the luminance of the illumination light is partially adjusted according to the luminance distribution of the display image.

As described above, according to the illumination device 50 and the liquid crystal display device 100 according to the present embodiment, the following effects can be obtained.
As described with reference to FIG. 7, the concave mirror 41 provided for each divided region d has a curvature for making light incident from the point light source 30 similar to the rectangular shape of the divided region.
Thus, unlike the conventional lighting device in which the luminance unevenness occurs due to the difference in the shape of the partial illumination light and the shape of the divided regions, according to the lighting device 50, as described in FIG. The shape of the partial illumination light Ao on the light exit surface S can be made substantially coincident with the shape of the divided region d.
In addition, the illumination device 50 is configured in the order of the sealing substrate 27, the point light source 30, the transparent substrate 25, and the concave mirror 41 from the light emitting surface S side, and the thickness of the transparent substrate 25 is adjusted by the adjustment substrate 22. Thus, the point light source 30 is arranged near the focal point of the concave mirror 41.
In particular, as described with reference to FIG. 6, the angle between the line segment L1 connecting the point light source 30 and one side of the outer shape of the concave mirror 41 and the center line Ce is the critical angle of the transparent substrate 25 with the air layer e. The thickness t3 of the transparent substrate 25 is set so as to substantially match. That is, only the light in the angle range smaller than the angle θ out of the light emitted from the point light source 30 can be emitted from the transparent substrate 25 and become partial illumination light. Therefore, independent brightness management is performed only in the divided area. be able to.
Therefore, unlike the conventional illuminating device in which it is difficult to control the luminance in the divided regions independently because the illumination light has greatly spread to the adjacent divided regions, according to the illuminating device 50, each divided region Independent brightness control can be performed.

Furthermore, unlike a conventional illumination device that requires two lenses to emit rectangular light, according to the illumination device 50, a single concave mirror 41 provided for each divided region d provides a rectangular cross section. The partial illumination light Ao can be emitted.
Therefore, the illumination device 50 can be configured to be thinner than the conventional illumination device.
Therefore, it is possible to provide the lighting device 50 that achieves both reduction in luminance unevenness and reduction in thickness. In other words, it is possible to provide an illumination device 50 having a thickness that allows independent brightness control for each divided region and can be used as a backlight of a liquid crystal panel.

In addition, as described with reference to FIG. 5, the plurality of scanning lines 34 are formed of ITO, and a gap G that can ensure electrical insulation is secured to form a wide wiring. The data line 35 has the same configuration.
Thereby, unlike the metal wiring in which the shielding and diffraction of the partial illumination light are concerned, there is no concern about the shielding and diffraction, and the wiring resistance of each wiring can be reduced to the same level as the metal wiring. Further, since the gap G is made small, the possibility that the gap is visually recognized is low.
Therefore, according to the illuminating device 50, uniform illumination can be performed.
The plurality of point light sources 30 are provided so that the luminance of the plurality of point light sources 30 can be independently controlled by a simple matrix line sequential driving method.
Accordingly, it is possible to provide the illumination device 50 that can control the luminance distribution of the illumination light emitted from the light exit surface S independently for each divided region d.

In addition, as described with reference to FIG. 2, the diffusion plate 15 is disposed between the lighting device 50 and the display panel 10.
Thereby, the shadow caused by the metal electrode 31 is blurred and becomes inconspicuous. Therefore, luminance unevenness can be reduced.
Further, the liquid crystal display device 100 adjusts the brightness of the partial illumination light emitted from the divided region d in units of the divided region d according to the luminance distribution of the display image per frame on the display panel 10.
Therefore, it is possible to provide the liquid crystal display device 100 that performs the local dimming method in which the luminance of the illumination light is partially adjusted according to the luminance distribution of the display image.

(Embodiment 2)
FIG. 9 is a side sectional view of the liquid crystal display device according to the second embodiment and corresponds to FIG. FIG. 10 is an exploded perspective view of the lighting device, and corresponds to FIG.
Hereinafter, a liquid crystal display device according to Embodiment 2 of the present invention will be described with reference to FIGS. The liquid crystal display device 110 according to this embodiment includes an illumination device 70 having a configuration different from that of the illumination device 50 of FIG. Except this point, it is the same as the liquid crystal display device 100 of the first embodiment.
Here, the description overlapping with the description in the first embodiment is omitted, and the configuration of the lighting device 70 will be mainly described. The same constituent parts will be described with the same numbers.

"Configuration of the lighting device"
As shown in FIG. 9, the diffusion plate 15 and the lighting device 70 are arranged in this order on the back side (Z-axis (+) side) of the display panel 10. This stacking direction (Z-axis (+) direction) is also referred to as a depth direction.
The illuminating device 70 includes a transparent substrate 25 on which a plurality of point light sources 30 are formed, a lens array substrate 60, and the like.
The illumination device 70 is configured in the order of the lens array substrate 60, the light shielding layer 63, the transparent substrate 25, and the point light source 30 in the depth direction from the light exit surface S side. A plurality of convex lenses 61 are arranged in a matrix on the lens array substrate 60. To be precise, the uneven surface of the plurality of convex lenses 61 of the lens array substrate 60 is the light emitting surface. However, for ease of explanation, the light emitting surface S is defined by a plane including (passing) the vertices of the plurality of convex lenses 61. It is said.

The transparent substrate 25 formed by bonding the element substrate 20 and the adjustment substrate 22 has the same configuration as that of the transparent substrate described in FIG. 2 except for the circuit configuration and wiring mode described later. (Axial direction) is reversed. Specifically, the adjustment substrate 22, the element substrate 20, and the point light source 30 are arranged in this order from the light emission surface S side. The surface of the transparent substrate 25 on the point light source 30 side (Z-axis (+) side) is a first surface 25a, and the surface on the lens array substrate 60 side (Z-axis (−) side) is a second surface 25b. .
That is, in the illuminating device 70, the light emitted from each point light source 30 is enlarged and shaped by the convex lens 61 of the lens array substrate 60 for each divided region d, so that the cross section is similar to that of the illuminating device 50 of the first embodiment. Rectangular partial illumination light is emitted.
The plurality of point light sources 30 are arranged one by one for each divided region d divided in a matrix shape on the first surface 25a of the transparent substrate 25, and a sealing substrate 27 is formed on the upper layer. . As the point light source 30, a light emitting element such as an LED element, an inorganic EL element, or an organic EL element can be used. Also in this embodiment, an organic EL element is employed as a suitable example.

The light shielding layer 63 is a light shielding portion disposed between the lens array substrate 60 and the transparent substrate 25, and has a lattice shape so as to partition the divided region d in plan view.
The light shielding layer 63 has two roles, one of which is to form an air layer e between the convex lens 61 and the second surface 25b of the transparent substrate 25 in each divided region d. The other is to prevent the partial illumination light from entering the adjacent divided region d by the thickness of the light shielding layer 63. In addition, it is preferable that the thickness of the light shielding layer 63 is in the range of about 0.03 mm to 0.2 mm. The width is preferably in the range of about 0.05 mm to 0.2 mm.
The light shielding layer 63 can be formed by, for example, pressing a black urethane resin or a resin film in a lattice shape. Alternatively, the light-shielding ink may be printed in a mesh pattern on the second surface 25b by a printing method such as an inkjet method or a screen printing method.

FIG. 10 is an exploded perspective view of the lighting device, but the light shielding layer 63 is omitted.
On the upper surface (Z-axis (−) side) of the lens array substrate 60, a plurality of convex lenses 61 are formed for each divided region d. In other words, each divided region d is defined by each convex lens 61 having a substantially square shape in plan view. Further, the surface of the lens array substrate 60 on the transparent substrate 25 side is a flat surface. And it lays out so that the point light source 30 corresponding to the central part of each division field d may be located.
The lens array substrate 60 is made of transparent resin, inorganic glass (optical glass), or the like. As the transparent resin, a thermoplastic resin such as acrylic or polycarbonate, or a photocuring resin such as an ultraviolet curable resin can be used. In addition, the lens array substrate 60 can be manufactured by a thermoforming, injection molding, cutting, polishing, photolithography, photomolding, inkjet, or other processing method, or a combination of these processing methods.

Returning to FIG.
Here, the convex lens 61 expands and shapes the light incident from the corresponding point light source 30, emits it as partial illumination light, and has a curvature for making the cross section of the light beam have a shape similar to the square of the divided region d. have. Details of the curvature will be described later.
As a result, as indicated by the arrows, the partial illumination light expanded and shaped by the convex lens 61 becomes a light beam having a square section substantially the same as that of the divided region d in plan on the light exit surface S.
As indicated by the arrows, the curvature of the convex lens 61 is a curvature that incorporates a refraction effect due to the difference in refractive index between the transparent substrate 25 and the air layer e.

"Specific optical design"
FIG. 11 is a side sectional view of the lighting device, and is an enlarged view of one divided region in FIG. 9. Further, this corresponds to FIG. 12A to 12C are explanatory diagrams of the curvature of the convex lens and correspond to FIG.
First, the method for setting the thickness of the transparent substrate 25 by the adjustment substrate 22 for arranging the point light source 30 at the approximate focal point of the convex lens 61 has been described with reference to FIG. 6 except that the transparent substrate 25 is inverted. This is the same as the setting method.

Specifically, as shown in FIG. 11, when a dashed line connecting the center 30c of the point light source 30 and the joint between the light shielding layer 63 on the second surface 25b of the transparent substrate 25 is defined as a line segment L1, it is transparent. The thickness t3 of the substrate 25 is set to a thickness such that an angle formed by the line segment L1 and the center line Ce is an angle θ. Note that the joint between the second surface 25b and the light shielding layer 63 corresponds to one side of the outer shape (divided region d) of the convex lens 61 projected onto the second surface 25b.
Here, the angle θ is set to a critical angle when entering the air layer e from the transparent substrate 25, which is the same as that of the illumination device 50 of the first embodiment.
Thereby, as shown by the arrow, only the light in the angle range smaller than the angle θ out of the light emitted from the point light source 30 can be emitted from the transparent substrate 25 and incident on the air layer e. On the other hand, light having an angle greater than the critical angle θ cannot exit the transparent substrate 25 and repeats total reflection within the transparent substrate 25.
Even if the light can enter the air layer e, the light traveling toward the light shielding layer 63 is absorbed by the light shielding layer 63. That is, the light traveling toward the light shielding layer 63 does not enter the adjacent divided region d (convex lens 61).

  In this way, the range (region) of light emitted from the transparent substrate 25 is limited. Since the divided area d is square in plan view, the same setting as in FIG. 11 is applied to the side cross section along the line segment passing through the center 30c of the point light source 30 and parallel to the Y axis. Yes. In other words, the X axis in FIG. 11 can be read as the Y axis.

Moreover, about a specific design aspect, it can design similarly using Formula (1), (2) demonstrated in Embodiment 1. FIG.
For example, there is a demand for a lighting device 70 having good contrast and energy efficiency even when the number of divisions is large. When the display panel 10 having a diagonal size of 5 inches is used, the lighting device 70 is designed as follows.
In this case, the size of the divided region d is about 2.0 mm square, and the size of the point light source 30 is about 0.2 mm square. The size of the light emission surface S is 80.0 mm long × 106.0 mm wide, and the light emission surface S is divided into divided regions of 40 rows × 53 columns.
In the case of this division number, the thickness t3 of the transparent substrate 25 is about 1.14 mm from Equation (2), so the thickness t2 of the adjustment substrate 22 is set to about 0.64 mm.

If the number of divisions is reduced and the manufacturing cost is to be suppressed even if the thickness is somewhat increased, the following design is performed.
For example, in the illumination device of the display panel 10 having a diagonal size of 5 inches, the case where the number of divisions is set to 221 which is about 1/10 of the above case is as follows.
In this case, the size of the divided region d is about 6.3 mm square, and the size of the point light source 30 is about 0.5 mm square. The size of the light emitting surface S is 81.9 mm long × 107.1 mm wide, and the light emitting surface S is divided into divided regions of 13 rows × 17 columns.
In the case of this division number, the thickness t3 of the transparent substrate 25 is about 3.6 mm from Equation (2), so the thickness t2 of the adjustment substrate 22 is set to about 3.1 mm.
Note that the above-described example is an example, and the number of divisions is not limited to the above-described numerical value, and the calculation formulas (1) and (2) are determined according to specifications such as image content, resolution, and thickness of the liquid crystal display device 110. ) Can be set as appropriate.

FIG. 12A is a plan view for explaining the curvature of the convex lens 61. In the drawing, a light flux pattern having a substantially circular cross section incident from the point light source 30 is a light flux Ai (broken line). A light flux pattern obtained by enlarging and shaping the light flux Ai by the convex lens 61 is indicated by a light flux Ao (solid line).
The substantially square shape indicated by the reference numeral 61 (d) indicates the outer shape (peripheral edge) of the convex lens 61 and has the same size as the divided region d. Further, the center is set as a center point 61c. In the convex lens 61, the curvature along the X axis passing through the center point 61c is defined as a curvature k11. Similarly, the curvature passing through the center point 61c and along the Y axis is the curvature k12. These are the reference curvatures in the horizontal and vertical directions of the convex lens 61. Further, the curvatures connecting the diagonal lines of the outer shape of the convex lens 61 are the curvature k13 and the curvature k14.

FIG. 12B is a side sectional view of the mm cross section of FIG. 12A, and the curvature of the curvature k13 (k14) is also indicated by a broken line for comparison. FIG. 12C is a perspective view of the convex lens 61. Here, the convex lens 61 has a curvature k11, k12 in the horizontal and vertical directions of the convex lens 61 and a curvature in the diagonal direction in order to convert the light beam Ai having a substantially circular cross section into a light beam Ao similar to the square of the divided region d. k13 and k14 are different. In other words, the curvatures k13 and k14 in the diagonal direction are set as curvatures for extending the diagonal direction in the substantially circular light beam Ai, as indicated by arrows in FIG.
Specifically, as shown in FIG. 12B, the curvature radius of the curvature k13 (k14) is set larger than the curvature radius of the curvature k11 (k12). Since the outer shape of the convex lens 61 is substantially square, the curvature k11 can be read as the curvature k12, and the curvature k13 can be read as the curvature k14. Then, as shown in FIG. 12 (c), the curvature is smoothly between the curvature k11 and the curvature k13, between the curvature k13 and the curvature k12, between the curvature k12 and the curvature k14, and between the curvature k14 and the curvature k11. Is changed to form the convex lens 61. Accordingly, as shown in FIG. 12A, the shape of the light beam Ao expanded by the convex lens 61 becomes a substantially square shape similar to the shape of the divided region d. Further, the convex lens 61 is arranged so that its size is slightly larger than that of the divided region d.

That is, the curvature of the convex lens 61 and the curvature of the concave mirror 41 described in FIG. 7 are set to be substantially the same when the mirror is inverted. In other words, for example, when the lens array substrate 60 is used as a male mold for injection molding, a molded product to be molded is the same as the mirror array substrate 40 including a plurality of concave mirrors 41 having a curved surface described above. .
Moreover, the aspect of the illumination light emitted from the light exit surface S of the illumination device 70 is the same as the illumination aspect described in FIG.

"Configuration of point light source and wiring mode"
FIG. 13 is a circuit configuration diagram of the point light source, and corresponds to FIG. FIG. 14 is a cross-sectional view in the vicinity of the point light source, and corresponds to FIG.
Subsequently, in the second embodiment, a circuit configuration for lighting and driving the plurality of point light sources 30 and a wiring mode will be described.
The lighting device 70 of the second embodiment can follow the circuit configuration and driving method (simple matrix line sequential driving) of the first embodiment. However, in this embodiment, the partial illumination light does not pass through the point light source. Since the configuration reaches the light exit surface, a circuit configuration and a driving method capable of controlling the luminance to a higher gradation are employed.

FIG. 13 is a circuit configuration diagram for lighting and driving the point light sources 30 in each divided region d. The illumination device 70 of the present embodiment employs an active matrix driving method.
Each divided region d is provided with a switching TFT (Thin Film Transistor) 86 for selecting a pixel, a driving TFT 87 for passing a current to the point light source 30, and a storage capacitor (capacitor) 88. Yes. These are also collectively referred to as a pixel circuit.
A scanning line 84 from the scanning line driving circuit 82 is connected to the gate terminal of the switching TFT 86, and a data line 85 from the data line driving circuit 83 is connected to the source terminal. The drain terminal of the switching TFT 86 is connected to the gate terminal of the driving TFT 87 and one end of the storage capacitor 88.

The source terminal of the driving TFT 87 and the other end of the storage capacitor 88 are connected to a VDD line to which a high power supply potential is supplied. The drain terminal of the driving TFT 87 is connected to the pixel electrode 89.
A point light source 30 made of an organic EL element (layer) is disposed between the pixel electrode 89 and the common electrode 91. The common electrode 91 is connected to the earth line.
The scanning line driving circuit 82 includes a shift register and an output buffer (both not shown), and sequentially supplies scanning signals to the plurality of scanning lines 84.
The data line driving circuit 83 includes a shift register and a latch circuit (both not shown), and supplies data signals to the plurality of data lines 85.
Then, the switching TFT 86 selected by the scanning signal is turned on, and the data signal is supplied to the driving TFT 87. As a result, the driving TFT 87 is turned on, a current corresponding to the voltage of the data signal flows from the VDD line to the point light source 30, and display light is emitted.
In parallel with the turning on of the driving TFT 87, the data signal is held in the holding capacitor 88, so that light emission is maintained for a time corresponding to the capacitance.

FIG. 14 is a side sectional view in the vicinity of the point light source and corresponds to FIG.
The configuration of the light source unit including the point light source 30 and the element substrate 20 in the present embodiment is classified into a bottom emission type in which light emitted from the point light source 30 is emitted from the element substrate 20 side.
In the light source unit, the element layer 81, the pixel electrode 89, the point light source 30, the common electrode 91, the adhesive layer 28, and the sealing substrate 27 are arranged in this order on the first surface 25a of the element substrate 20. It is laminated and configured.
A partition wall 90 for partitioning the point light source 30 is formed on the element layer 81. The partition wall 90 is made of, for example, a black resin, and partitions the point light sources in each divided region.

In the element layer 81, circuit elements such as the switching TFT 86, the driving TFT 87, and the storage capacitor 88 described in FIG. 13, the scanning line 84, the data line 85, and the like are formed. These circuit elements and wirings are arranged so as to overlap the partition wall 90. For example, FIG. 14 shows a state where the drain terminal of the driving TFT 87 arranged so as to overlap the partition wall 90 and the pixel electrode 89 made of a transparent electrode such as ITO are connected.
In the element layer 81, a region overlapping with the point light source 30 is formed transparently by an interlayer insulating film made of, for example, SiO ₂ .
The common electrode 91 is a reflective layer or electrode composed of a material having both conductivity and reflectivity, such as an Mg—Ag alloy, and is formed so as to cover the point light source 30 and the partition wall 90.
With these configurations, the light emitted from the point light source 30 passes through the pixel electrode 89 and the element layer 81 and is emitted from the second surface 25b of the transparent substrate 25 as indicated by a white arrow. become. As described above, since light does not pass through the portion overlapping with the partition wall 90, a metal material is used for the wiring of the element layer 81.
The configuration of the organic EL element (layer) as the point light source 30 is the same as that described with reference to FIG. 5B. However, since the top of the transparent substrate 25 is inverted as described above, the organic EL element is reversed. The stacking direction of the layers is reversed. Specifically, from the pixel electrode 89 side, a hole transport layer, a light emitting layer, and an electron injection layer are laminated in this order. That is, the electron injection layer is disposed on the common electrode 91 side.

As described above, according to the liquid crystal display device 110 according to the present embodiment, in addition to the effects of the first embodiment, the following effects can be obtained.
As described with reference to FIG. 12, the convex lens 61 provided for each divided region d has a curvature for making the light incident from the point light source 30 similar to the rectangular shape of the divided region.
Thus, unlike the conventional illumination device in which the luminance unevenness has occurred due to the difference in the shape of the partial illumination light and the shape of the divided regions, according to the illumination device 70, the portion on the light exit surface S The shape of the illumination light Ao can be made substantially coincident with the shape of the divided region d.
In addition, the illumination device 70 is configured in the order of the lens array substrate 60, the light shielding layer 63, the transparent substrate 25, and the point light source 30 from the light emission surface S side, and the thickness of the transparent substrate 25 is adjusted by the adjustment substrate 22. Thus, the point light source 30 is disposed in the vicinity of the focal point of the convex lens 61.

In particular, as described with reference to FIG. 11, when the dashed line connecting the center 30 c of the point light source 30 and the joint between the light shielding layer 63 on the second surface 25 b of the transparent substrate 25 is a line segment L <b> 1, The thickness t3 of 25 is set to a thickness at which the angle formed by the line segment L1 and the center line Ce is an angle θ (critical angle of the transparent substrate 25). That is, only the light in the angle range smaller than the angle θ out of the light emitted from the point light source 30 can be emitted from the transparent substrate 25 and become partial illumination light. Therefore, independent brightness management is performed only in the divided area. be able to.
Therefore, unlike the conventional lighting device in which it is difficult to independently control the luminance in the divided regions because the illumination light has greatly spread to the adjacent divided regions, according to the lighting device 70, for each divided region. Independent brightness control can be performed.

Furthermore, unlike a conventional illumination device that requires two lenses to emit rectangular light, according to the illumination device 70, a single convex lens 61 provided for each divided region d provides a rectangular cross section. The partial illumination light Ao can be emitted.
Therefore, the illumination device 70 can be configured to be thinner than the conventional illumination device.
Therefore, it is possible to provide the illumination device 70 that achieves both reduction in luminance unevenness and reduction in thickness. In other words, it is possible to provide an illumination device 70 having a thickness that allows independent luminance control for each divided region and can be used as a backlight of a liquid crystal panel.
From another point of view, the illumination lens mainly composed of the convex lens 61 has the same effect as that of the illumination device 50 according to the first embodiment, in which the luminance mirror is reduced and the thickness is reduced with the configuration mainly composed of the concave mirror 41. It can also be realized by the device 70.

Further, as described with reference to FIGS. 13 and 14, the lighting device 70 employs an active matrix driving method to drive and drive the plurality of point light sources 30.
Therefore, compared with a passive driving method such as simple matrix driving, responsiveness and emission luminance can be controlled more finely (high gradation). Further, in the case of simple matrix driving, since it is duty driving, high luminance is required instantaneously, and a load is imposed on the organic EL element. However, active matrix driving is advantageous also in this respect. Therefore, it is possible to provide the lighting device 70 with high responsiveness and capable of finely controlling the light emission luminance (high gradation).

(Electronics)
FIG. 15 is a diagram showing a multimedia player equipped with the liquid crystal display device.
The liquid crystal display device 100 can be used by being mounted on, for example, a portable MMP (multimedia player) 500 as an electronic device.
The MMP 500 is provided so as to be able to reproduce music, videos, photos, and the like stored in a built-in hard disk drive, a memory device, and the like.
The MMP 500 includes the liquid crystal display device 100 as a display unit, and by operating a plurality of operation buttons 510, it is possible to display stored moving images, photos, and the like.
For example, when moving images such as movies are displayed, it is possible to control brightness so that bright areas are bright and dark areas are dark according to the contrast of the display image. An image can be obtained. Further, since it is possible to darken the illumination of a dark region or a dark image, power consumption can be suppressed as compared with a conventional illumination device that performs illumination with uniform brightness.
Thus, by providing the liquid crystal display device 100 as a display unit, it is possible to perform independent luminance control for each divided region, and it is possible to provide a thin MMP 500 that is excellent in energy saving effect.
The liquid crystal display device 100 may be replaced with the liquid crystal display device 110, and even with these configurations, the same operational effects as those of the liquid crystal display device 100 can be obtained.

Further, the electronic device is not limited to the MMP, and any electronic device including a display panel may be used.
For example, it can be used in various electronic devices such as mobile phones, display devices for car navigation systems, PDAs (Personal Digital Assistants), mobile computers, digital cameras, digital video cameras, in-vehicle devices, and audio devices.
Even with these electronic devices, the same effects as the MMP 500 can be obtained.

  Note that the present invention is not limited to the above-described embodiment, and various modifications and improvements can be added to the above-described embodiment. A modification will be described below.

(Modification 1)
FIG. 16 is a side sectional view of a liquid crystal display device according to the first modification, and corresponds to FIG.
Here, the liquid crystal display device 105 according to the first modification will be described with reference to FIG.
The liquid crystal display device 105 according to the first modification includes an illumination device 55 that is different from the illumination device 50 of the liquid crystal display device 100 of the first embodiment. Specifically, the illumination device 55 is different from the illumination device 50 of the first embodiment in that the illumination device 55 includes a light shielding layer 43. In other words, the configuration of the lighting device 55 is the same as that of the lighting device 50 of the first embodiment except that the light shielding layer 43 is provided.
Hereinafter, the description overlapping with the description in the first embodiment will be omitted. In addition, about the same component, it attaches | subjects and demonstrates the same number.

As shown in FIG. 16, a light shielding layer 43 is formed between the transparent substrate 25 and the mirror array substrate 40. Specifically, a light shielding layer 43 is formed between the adjustment substrate 22 of the transparent substrate 25 and the peripheral edge of the concave mirror 41 of the mirror array substrate 40.
In a plan view, the light shielding layer 43 is a black light shielding layer formed in a lattice shape along the outer shape (divided region d) of the concave mirror 41.
The light shielding layer 43 can be formed by the same material and manufacturing method as the light shielding layer 63 described in FIG. The thickness and width of the light shielding layer 43 are the same as those of the light shielding layer 63.
Here, as a preferred example, a black resin film pressed into a lattice shape is used as the light shielding layer 43.
Since the light shielding layer 43 is provided, the gap between the peripheral edge of the concave mirror 41 and the adjustment substrate 22 is filled, so that the partial illumination light can be prevented from entering the adjacent divided region d.
Accordingly, it is possible to provide the lighting device 55 and the liquid crystal display device 105 with reduced luminance unevenness.

(Modification 2)
17 is a plan view showing an aspect of the point light source according to the second modification, and is a transmission plan view when the point light source is observed from the second surface 25b side of the transparent substrate 25 in FIG.
In the illuminating device according to the modified example 2, one point light source 39 is composed of an assembly of minute red (R), green (G), and blue (B) element light sources (light emitting elements). Specifically, the point light source 39 includes an organic EL element 39R that emits red light, an organic EL element 39G that emits green light, and an organic EL element 39B that emits blue light. The organic EL elements 39R, 39G, and 39B correspond to element light sources.
The organic EL element 39R is formed in the same manner as the stacked structure of FIG. 14, and is different from the configuration of the second embodiment in that the light emitting layer of the organic EL element is an organic material that emits red light. Similarly, an organic material that emits green light is used for the light emitting layer of the organic EL element 39G, and an organic material that emits blue light is used for the light emitting layer of the organic EL element 39B.

In addition, each of the organic EL elements 39R, 39G, and 39B is arranged in close proximity as a set, and each is partitioned by a partition wall 90 (FIG. 14), and the pixel circuit described in FIG. 13 is provided for each element. It has been.
That is, light obtained by combining the light emitted from the three organic EL elements 39R, 39G, and 39B is emitted as partial illumination light of the point light source 39. Each of the three organic EL elements 39R, 39G, and 39B is configured to be able to be lit and driven independently.
Therefore, each of the point light sources 39 can emit light of various colors by adjusting the luminance of each organic EL element 39R, 39G, 39B. Also, white light with slightly different color variations can be emitted even with white light.

Further, the organic EL elements 39R, 39G, and 39B in the uppermost point light source 39 in FIG. 17 are arranged from the upper side (X axis (−) side) of the left side (X axis (−) side) to the lower side. The elements 39R and 39G are arranged in this order, and the organic EL element 39B is arranged on the right side (X-axis (+) side) of the arrangement.
Further, the arrangement of the lower point point light sources 39 is a delta arrangement in which the organic EL elements 39B and 39R are arranged in order from the upper left side to the lower side, and the organic EL element 39G is arranged on the right side of the arrangement. ing.
Further, the arrangement of the lower point light sources 39 is arranged in the order of the organic EL elements 39G and 39B from the upper left side to the lower side, and a delta arrangement in which the organic EL element 39R is arranged on the right side of the arrangement. ing.
That is, the arrangement of the element light sources is changed for each arrangement line of the point light sources 39. In other words, the color tone in the delta arrangement rotates counterclockwise by one for each arrangement row.
As a result, it is possible to cancel the color light mist caused by the arrangement of the element light sources in the point light source 39 in units of arrangement rows, and to make the illumination light uniform.
Therefore, according to the illuminating device which concerns on the modification 2, light emission luminance can be controlled more finely (to high gradation). In addition, illumination with abundant color variations including illumination with light of various colors can be performed.

In the above description, each element light source has been described as an organic EL, but may be an inorganic EL element or an LED. The light emission color of the element light source is not limited to RGB, and may be, for example, color light such as cyan, magenta, and yellow, or may be a combination of these in addition to RGB. Moreover, the size of each element light source does not need to be the same, for example, you may set the size of the element light source of the color light which tends to be insufficient.
In addition, the configuration of one point light source by an assembly of a plurality of element light sources can also be applied to the illumination device 50 of the first embodiment.
Even if it is these structures, the effect similar to the modification 2 can be acquired.

(Modification 3)
This will be described with reference to FIG.
In each of the above embodiments, the divided area d has been described as being substantially square. However, the present invention is not limited to this, and the divided area d may be rectangular.
For example, in the illumination device 50 according to the first embodiment, when the size of the display area V of the display panel 10 is 5 inches diagonal, the size of the divided area d is 6.3 mm × horizontal direction (Y-axis direction) (X-axis direction) A 8.2 mm rectangle may be used.
In this case, the light exit surface S is divided into 13 rows × 13 columns, and the size of the light exit surface S is 81.9 mm long × 106.6 mm wide. The number of divisions is 169.
Further, in this case, the thickness t3 (FIG. 6) of the transparent substrate 25 is determined from the formulas (1) and (2) with the rectangular short side direction (6.3 mm) as the width w. The thickness t3 is about 3.6 mm.

This will be described with reference to FIG.
Here, description will be made assuming that the outer shape (divided region d) of the concave mirror 41 in FIG. In other words, the description will be made assuming that the concave mirror 41 in FIG. 7A is a horizontally long rectangle toward the paper surface.
When the concave mirror 41 has a rectangular outer shape, in order to convert the light beam Ai having a substantially circular cross section incident from the point light source 30 into a light beam Ao having a rectangular cross section, a longitudinal curvature k2 and a lateral curvature k1 are obtained. Need to be different. Similarly to the description in the first embodiment, it is necessary to make the curvature k1 in the horizontal direction different from the curvature k3 (k4) in the diagonal line.
Specifically, the curvature of the concave mirror 41 is set so that the curvature increases in the order of the curvature k2 in the vertical direction, the curvature k1 in the horizontal direction, and the curvature k3 (k4) in the diagonal line.
According to this structure, the freedom degree of design of an illuminating device can be raised.
Further, if the curvature of the concave mirror 41 is mirror-inverted, it can be applied to the convex lens 61 of FIG. In other words, also in the illuminating device 70 of Embodiment 2, the division area d can be formed in a rectangle.

  DESCRIPTION OF SYMBOLS 10 ... Display panel, 25 ... Transparent substrate, 25a ... First surface of transparent substrate, 25b ... Second surface of transparent substrate, 30, 39 ... Point light source, 31 ... Metal electrode, 34 ... Scanning as first transparent electrode 35, data line as second transparent electrode, 39R, 39G, 39B ... organic EL element as element light source, 41 ... concave mirror, 43, 63 ... light shielding layer as light shielding part, 50, 70 ... illumination device, 61 ... convex lens, 100, 105, 110 ... liquid crystal display device as electro-optical device, 500 ... MMP as electronic device, d ... divided region, S ... light exit surface, θ ... angle (critical angle).

Claims (15)

A point light source;
A mirror array substrate having a concave mirror formed at a position corresponding to the point light source,
The concave mirror is formed in a substantially rectangular divided region on the surface of the mirror array substrate on the point light source side,
The concave part of the concave mirror is
In a cross section in the direction of the diagonal line of the divided region, it has a first curvature,
It has a second curvature that is different from the first curvature in a cross section in a first direction that passes through the intersection of two diagonal lines of the divided region and is parallel to one side of the divided region. Lighting device. The lighting device according to claim 1.
The lighting device according to claim 1, wherein the first curvature is smaller than the second curvature. The lighting device according to claim 1 or 2,
A transparent substrate disposed between the point light source and the mirror array substrate;
The concave part of the concave mirror has a space between the transparent substrate and
In the cross section in the first direction,
A perpendicular line extending from the edge of the divided region to the transparent substrate is a first straight line,
When a straight line connecting the intersection of the first straight line and the surface of the transparent substrate on the mirror array substrate side and the point light source is a second straight line,
The transparent substrate has a refractive index and a thickness such that an angle formed by the first straight line and the second straight line is substantially equal to a critical angle at which light in a direction from the transparent substrate toward the space is reflected. A lighting device. The lighting device according to claim 3.
A light-shielding portion disposed between the transparent substrate and the mirror array substrate;
The illumination device according to claim 1, wherein the light-shielding portion has a lattice shape that overlaps a side of the divided region in a plan view as viewed from a direction perpendicular to the surface of the transparent substrate. The lighting device according to claim 3 or 4,
A first transparent electrode disposed on the surface of the transparent substrate on the point light source side;
A metal electrode disposed on the surface of the transparent substrate on the point light source side;
A second transparent electrode disposed on the surface of the transparent substrate on the point light source side,
The point light source is an EL element or an LED element,
The said metal electrode is arrange | positioned in the position which overlaps with the said point light source, and is electrically connected with the said 2nd transparent electrode, The illuminating device characterized by the above-mentioned. A point light source;
A lens array substrate having a convex lens formed at a position corresponding to the point light source,
The convex lens is formed in a substantially rectangular divided region on the surface of the lens array substrate opposite to the point light source,
The convex part of the convex lens is
In a cross section in the direction of the diagonal line of the divided region, it has a first curvature,
It has a second curvature that is different from the first curvature in a cross section in a first direction that passes through the intersection of two diagonal lines of the divided region and is parallel to one side of the divided region. Lighting device. The lighting device according to claim 6.
The lighting device according to claim 1, wherein the first curvature is smaller than the second curvature. The lighting device according to claim 6 or 7,
Between the point light source and the lens array substrate, having a transparent substrate arranged to have a space,
In the cross section in the first direction,
A perpendicular line extending from the edge of the divided region to the transparent substrate is a first straight line,
When a straight line connecting the intersection of the first straight line and the surface of the transparent substrate on the lens array substrate side and the point light source is a second straight line,
The transparent substrate has a refractive index and a thickness such that an angle formed by the first straight line and the second straight line is substantially equal to a critical angle at which light in a direction from the transparent substrate toward the space is reflected. A lighting device. The lighting device according to claim 8.
A light-shielding portion disposed between the transparent substrate and the lens array substrate;
The illumination device according to claim 1, wherein the light-shielding portion has a lattice shape that overlaps a side of the divided region in a plan view as viewed from a direction perpendicular to the surface of the transparent substrate. In the illuminating device in any one of Claims 1 thru | or 9,
The point light source is an assembly of a plurality of element light sources including red, blue, and green. In the illuminating device in any one of Claims 1 thru | or 10,
The lighting device according to claim 1, wherein the divided area is a square. The lighting device according to any one of claims 1 to 11,
A transmissive or transflective display panel having a rectangular display area, and
An electro-optical device, wherein the display panel and the illumination device are arranged so as to face each other so that a back surface of the display area faces a light emission surface of the illumination device. The display area is formed of a large number of pixels.
The electro-optical device according to claim 12, wherein the divided region is formed to have substantially the same size as a pixel region including the plurality of pixels among the plurality of pixels.   The electro-optical device according to claim 12, wherein the display panel is a liquid crystal panel.   An electronic apparatus comprising the electro-optical device according to claim 12 as a display unit.

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