JP2014235896A - Surface light source device, display unit, and luminaire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface light source device suitable to a display unit whose frame region is not seen or a display unit which has high pixel transmissivity.SOLUTION: A surface light source device 1 includes: an LED 2; a box body 3 which has a light emission surface having at least one opening part 6, guides light made incident from the LED 2 while reflecting the light in an inner space, and emits the light from the opening part 6; and a cylindrical lens array 4 including at least one cylindrical lens 7 on which the light emitted from the light emission surface of the box body 3 is made incident. The cylindrical lens 7 has a lens surface having curvature at least in a first direction between the first direction and a second direction which cross each other in a virtual plane orthogonal to the optical axis of the cylindrical lens 7, and the cylindrical lens 7 has its focus substantially at the position of the opening part 6.

Description

  The present invention relates to a surface light source device, a display device, and an illumination device.

  As an example of a display device, a transmissive liquid crystal display device that performs display using light emitted from a surface light source device is known. The transmissive liquid crystal display device includes a liquid crystal panel and a surface light source device disposed on the back side of the liquid crystal panel. In this specification, this type of surface light source device may be referred to as a backlight. Generally, the display surface of a liquid crystal panel has a display area that directly contributes to display and a non-display area that does not directly contribute to display. In the liquid crystal display device, in order to efficiently use the light emitted from the backlight, a configuration for preventing the light emitted from the backlight from entering the non-display area of the liquid crystal panel has been studied.

  One of them is a structure for preventing light from being incident on a non-display area on the periphery of the liquid crystal panel, that is, a so-called frame area. According to this configuration, in addition to being able to use light effectively by not allowing light to enter the frame area, a liquid crystal display device is provided in which the frame area is not visible to the user, and the entire surface of the liquid crystal panel is the display area. can do. As a technique for making the frame region invisible, a display device including a backlight module, an optical film having a Fresnel structure, a display panel, and a convex lens having a Fresnel structure has been proposed (for example, the following patent document) 1). In this display device, the light emitted from the backlight module in the front direction is diverged by a concave lens-shaped optical film, and after passing through the display panel diagonally, it is collimated by a convex lens having a focal point at the same position as the optical film. To do. As a result, it appears as if light is emitted from the position of the frame area to the user who sees through the convex lens, and as a result, the frame area becomes invisible.

  The other is a configuration for preventing light from entering a lattice-shaped light shielding portion that partitions each pixel of the liquid crystal panel, a so-called black matrix. As a technique for preventing light from being incident on the black matrix, a liquid crystal display device including an illumination device, a liquid crystal display panel, and a microlens array disposed between the illumination device and the liquid crystal display panel has been proposed. (For example, the following patent document 2). Each of the plurality of microlenses constituting the microlens array is arranged so as to correspond to a pixel of the liquid crystal display panel. In this liquid crystal display device, light having a high degree of parallelism emitted from the illumination device is focused and transmitted through the aperture of the pixel by the microlens, thereby increasing the light use efficiency from the illumination device.

US Patent Application Publication No. 2010/0253591 JP 2007-193346 A

  The display device of Patent Document 1 employs a method of erasing the frame region by stretching the image at an average magnification expressed by (total area including frame region and display region) / (total area of display region). . In the case of this display device, optical members necessary for erasing the frame area, such as an optical film having a Fresnel structure and a convex lens, are arranged over the entire screen. As a result, there is a problem that the image is distorted overall.

  In the liquid crystal display device of Patent Document 2, the size of the microlens is equal to the size of the pixel (for example, about several tens to several hundreds of μm). For this reason, the same number of light emitting diodes (hereinafter abbreviated as LEDs) as microlenses are required in order to make the luminance uniform over the entire screen using a direct type illumination device. In that case, since the number of LEDs becomes enormous and cannot be realized, an edge light type illumination device is used. However, when an edge light type illumination device is used, there is a problem that it is difficult to increase the amount of light and a bright image cannot be obtained if the liquid crystal display device is to be enlarged.

  One aspect of the present invention has been made to solve the above-described problem, and an object of the present invention is to provide a display device in which the frame region is not visible and the overall image distortion can be reduced. One embodiment of the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a display device that has high light use efficiency per pixel and can obtain a bright image. An object of one embodiment of the present invention is to provide a surface light source device suitable for use in the above display device. An object of one embodiment of the present invention is to provide a bright lighting device by using the surface light source device.

  In order to achieve the above object, a surface light source device according to one aspect of the present invention includes a light source and a light emission surface having at least one light transmission part, and reflects light incident from the light source in an internal space. A box body that is guided while being emitted from the light transmitting portion, and a lens member that includes at least one unit lens on which light emitted from the light exit surface of the box body is incident, and the unit lens A lens surface having a curvature in at least the first direction out of a first direction and a second direction orthogonal to each other in a virtual plane orthogonal to the optical axis of the unit lens, and the focal point of the unit lens Is substantially coincident with the position of the light transmitting portion.

  In the surface light source device according to one aspect of the present invention, the light transmitted through the unit lens is substantially parallelized in the first direction.

  In the surface light source device according to one aspect of the present invention, the unit lens is configured by a cylindrical lens, and the longitudinal direction of the planar shape of the light transmission portion viewed from the normal direction of the light exit surface is the longitudinal direction of the cylindrical lens. It may be substantially parallel to the direction.

  In the surface light source device according to one aspect of the present invention, the unit lens is formed of a cylindrical lens, the light emitting surface is provided with a plurality of the light transmissive portions, and the plurality of light transmissive portions are longitudinal portions of the cylindrical lens. You may arrange | position at intervals in the direction substantially parallel to a direction.

  In the surface light source device according to one aspect of the present invention, an area of the light transmission portion at a position relatively close to the light source among the plurality of light transmission portions is relatively small and relatively far from the light source. The area of the light transmission part in the position may be relatively large.

  In the surface light source device according to one aspect of the present invention, an arrangement density of the light transmission parts at a position relatively close to the light source among the plurality of light transmission parts is relatively low and The disposition density of the light transmission parts at a distant position may be relatively high.

  In the surface light source device according to one aspect of the present invention, the light transmission part is preferably a hole provided in the box.

  A display device according to one aspect of the present invention includes a surface light source device according to one aspect of the present invention, a display element that performs display using light emitted from the surface light source device, the lens member, and the display element. A first light deflection element that is provided between the display element and deflects the traveling direction of the light emitted from the peripheral edge of the lens member toward the peripheral edge of the display element; and provided on the light emission surface side of the display element. A second light deflecting element that deflects the traveling direction of the light deflected by the first light deflecting element in the normal direction of the display surface of the display element after passing through the peripheral edge of the display element; The display element includes a display region and a frame region located around the display region.

  In the display device according to one aspect of the present invention, the first light deflection element may be constituted by a prism sheet having a plurality of prisms arranged to face the peripheral edge of the lens member.

  In the display device according to one aspect of the present invention, the second light deflection element includes a light-transmitting base material and a light-transmitting structure provided on the first surface of the base material at a distance. A plurality of light deflecting portions, and the light deflecting portion is positioned on the opposite side of the light incident end surface with the light incident end surface in contact with the first surface of the substrate. A light exit end surface and a reflection surface facing a gap existing between the adjacent light deflection units, and an angle formed by the reflection surface and the light incident end surface is an acute angle, and the light deflection unit In the configuration, the light incident from the light incident end surface may be reflected by the reflecting surface and emitted from the light emitting end surface.

  In the display device according to one aspect of the present invention, the plurality of light deflection units are provided in a region facing at least the frame region of the display element in a peripheral portion of the base material, and in the central portion of the base material. A light transmission portion may be provided in a region other than the region where the light deflection portion is formed.

  In the display device according to one aspect of the present invention, an angle formed between the reflection surface and the light incident end surface in the plurality of light deflection units is far from the light transmission unit from the light deflection unit closer to the light transmission unit. It may be gradually reduced toward the light deflection unit on the side.

  In the display device according to one aspect of the present invention, the second light deflection element may be formed of a light scattering film disposed on the light emission surface side of the display element.

  In the display device according to one aspect of the present invention, the planar shape of the display region is a rectangle, and the lens member includes a plurality of cylindrical lenses arranged in different directions, and is near each side of the display element. The cylindrical lens that is positioned may be arranged so that the axis of the cylindrical lens is substantially parallel to the side of the nearby display element.

  A display device according to one aspect of the present invention includes the surface light source device according to one aspect of the present invention and a display element that performs display using light emitted from the surface light source device, and the display element is a matrix. And a lens array having a plurality of lenses for focusing light incident from the lens member on the openings of the light shielding layer. The first direction substantially coincides with a direction parallel to an arbitrary side of the rectangle forming the planar shape of the opening.

  In the display device according to one aspect of the present invention, the planar shape of the opening may be substantially rectangular, and the first direction may substantially coincide with a direction parallel to a short side of the planar shape of the opening.

  In the display device according to one aspect of the present invention, the display element includes a plurality of source bus lines and a plurality of gate bus lines orthogonal to the plurality of source bus lines, and the source bus lines have the openings. The gate bus line may extend in parallel to the short side of the planar shape of the opening.

  In the display device according to one aspect of the present invention, the display element may be a liquid crystal panel that modulates the transmittance of light emitted from the surface light source device.

  In the display device according to one aspect of the present invention, a light diffusion member for expanding a diffusion angle of light emitted from the liquid crystal panel may be provided on the light emission side of the liquid crystal panel.

  An illumination device according to one aspect of the present invention includes the surface light source device according to one aspect of the present invention.

  According to one aspect of the present invention, it is possible to realize a display device in which a frame region is not visible and image distortion can be reduced. According to one aspect of the present invention, it is possible to realize a display device that can obtain a bright image with high light use efficiency per pixel. According to one aspect of the present invention, a surface light source device suitable for use in the display device described above can be realized. According to one aspect of the present invention, a bright illumination device can be realized by using the surface light source device.

It is a perspective view of the surface light source device of 1st Embodiment. It is a top view of a surface light source device. FIG. 3 is a cross-sectional view taken along line A-A ′ of FIG. 2. It is an expanded sectional view which shows the principal part of FIG. FIG. 3 is an enlarged sectional view taken along line C-C ′ of FIG. 2. FIG. 4 is a sectional view taken along line B-B ′ in FIG. 3. It is a top view of the surface light source device of 2nd Embodiment. It is sectional drawing which follows the B-B 'line of FIG. It is a top view of the surface light source device of 3rd Embodiment. It is a perspective view which shows three modifications of (A)-(C) cylindrical lens. It is a top view of the liquid crystal display device of 4th Embodiment. It is sectional drawing which follows the A-A 'line | wire of FIG. It is a perspective view of the surface light source device used for the liquid crystal display device of this embodiment. It is a figure which shows the simulation result of the light deflection characteristic of the prism sheet used for the liquid crystal display device of this embodiment. It is a figure for demonstrating the effect | action of the light bending sheet | seat used for the liquid crystal display device of this embodiment. It is sectional drawing of the liquid crystal display device of 5th Embodiment. It is sectional drawing of the liquid crystal display device of 6th Embodiment. It is a perspective view of the liquid crystal display device of 7th Embodiment. It is sectional drawing which follows the A-A 'line | wire of FIG. 2A is an equivalent circuit diagram of a TFT substrate constituting a liquid crystal display device, and FIG. 2B is a plan view of a pixel. (A) It is a figure which shows the model of the simulation which demonstrates the effect of this embodiment, (B) It is a figure which shows the luminance distribution of the uniaxial directivity light source used for simulation, (C) It is a top view of the pixel used for simulation is there. (A)-(C) It is a figure which shows a simulation result when changing illumination intensity distribution into three kinds. It is sectional drawing of the liquid crystal display device of 8th Embodiment. It is a front view which shows one structural example of a display apparatus. It is a side view of the illuminating device of 9th Embodiment.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
In the first embodiment, an example of a surface light source device suitable for use in the liquid crystal display devices of the fourth to eighth embodiments or the illumination device of the ninth embodiment will be described.
FIG. 1 is a perspective view of the surface light source device of the first embodiment. FIG. 2 is a plan view of the surface light source device. FIG. 3 is a cross-sectional view taken along line AA ′ of FIG. FIG. 4 is an enlarged cross-sectional view showing a main part of FIG. FIG. 5 is an enlarged cross-sectional view taken along the line CC ′ of FIG. 6 is a cross-sectional view taken along line BB ′ of FIG.
In the following drawings, in order to make each component easy to see, the scale of the size may be varied depending on the component.

  As shown in FIG. 1, the surface light source device 1 of the present embodiment includes an LED 2 (light source), a box 3, and a cylindrical lens array 4 (lens member). The cylindrical lens array 4 is disposed so as to face a top plate 3a of the box 3 described later. In FIG. 1, the distance between the cylindrical lens array 4 and the box 3 is drawn with a large distance in order to make the drawing easy to see. Actually, the cylindrical lens array 4 and the box 3 are arranged closer to each other. The cylindrical lens array 4 and the box 3 may be in close contact with each other. The thickness direction of the surface light source device 1 is defined as the z-axis, the longitudinal direction of the cylindrical lens 7 described later is defined as the y-axis, and the short direction of the cylindrical lens 7 is defined as the x-axis.

  The box 3 has a substantially rectangular parallelepiped shape. As shown in FIGS. 3 and 6, the inside of the box 3 is hollow and air is present. As shown in FIG. 2, the top plate 3a and the bottom plate 3b of the box 3 have a rectangular shape when viewed from the normal direction. As shown in FIG. 3, the top plate 3 a and the bottom plate 3 b are each made of plate materials that are parallel to the xy plane and arranged in parallel to each other. The outer peripheries of the top plate 3a and the bottom plate 3b are surrounded by four side plates 3c and 3d.

  The LED 2 is installed at the approximate center of the bottom plate 3 b of the box 3. The LED 2 does not need to have a specific function or performance, and a general commercially available LED 2 can be used. Although the surface light source device 1 of this embodiment emits light having uniaxial directivity, the LED 2 itself does not need to emit light having directivity. A general LED 2 that emits diffused light can be used. As shown in FIG. 3, the LED 2 is fixed to the box 3 so that the light emission surface 2 a of the LED 2 faces the inside of the box 3. Thereby, the LED 2 emits light toward the internal space of the box 3. Hereinafter, the internal space of the box 3 is referred to as a cavity 5.

  The box 3 is comprised with various materials, such as a metal and a plastics, for example, and a material is not specifically limited. However, the inner surface 3 i of the box 3 facing the cavity 5 needs to be a reflecting surface that reflects the light L. The reason is that the light L emitted from the LED 2 needs to be guided through the cavity 5 while being reflected by the inner surface 3 i of the box 3 a plurality of times. Therefore, in order to minimize the loss of the light L during reflection, it is desirable that the light reflectance of the inner surface 3i of the box 3 is as high as possible. Therefore, for example, when the box 3 is made of plastic, a reflective film made of a material having high light reflectivity may be provided on the inner surface 3i of the box 3. As the material of the box 3, particularly the highly reflective material of the inner surface 3 i, it is preferable to use a fine foam resin, a biaxially stretched resin, a dielectric multilayer film, a metal film, or the like.

  At least a part of the inner surface 3 i of the box 3 may be a scattering reflection surface that scatters and reflects the light L emitted from the LED 2. Alternatively, at least a part of the inner surface 3 i of the box 3 may be a regular reflection surface that regularly reflects the light L emitted from the LED 2. For example, all of the inner surface 3i of the box 3 may be a scattering reflection surface, or all of the inner surface 3i of the box 3 may be a regular reflection surface. Alternatively, the regular reflection surface and the scattering reflection surface may be mixed, such that the inner surface 3i of the top plate 3a is a regular reflection surface and the inner surface 3i of the bottom plate 3b is a scattering reflection surface. The box 3 may be integrally molded, or may be a combination of a plurality of members.

  As shown in FIGS. 1 to 3, the top plate 3 a of the box 3 is provided with a plurality of openings 6 that allow the external space of the box 3 to communicate with the cavity 5. The planar shape of the opening 6 is an elongated rectangle, which is a so-called slit. Four openings 6 are provided in the top plate 3 a of the box 3. The four openings 6 are provided at equal pitches with the longitudinal directions of the openings 6 being parallel to each other and spaced apart in the short direction of the top plate 3a.

  The light L emitted from the LED 2 is repeatedly reflected by the inner surface 3 i of the box 3 and guided inside the cavity 5. That is, as shown in FIG. 3, the light L emitted from the LED 2 is repeatedly reflected between the inner surface 3i of the top plate 3a and the inner surface 3i of the bottom plate 3b, as shown in FIG. , In the xy section, reflection is repeated between the four side plates 3c and 3d.

  For example, if the light reflectivity of the inner surface 3i of the box 3 is 95%, a 5% light loss occurs at the time of reflection, but most other light L is guided through the cavity 5. The light L is guided through the cavity 5 unless it reaches the opening 6 of the top plate 3a. When the light L reaches the opening 6 of the top plate 3a, the light L is taken out of the box 3. Therefore, the top plate 3a of the box 3 provided with the opening 6 serves as a light emission surface for taking out the light L from the LED 2.

  As shown in FIG. 3, it is desirable that at least the outer surface 3h facing the cylindrical lens array 4 of the outer surface of the box 3 is a light absorbing surface provided with, for example, a black coating film. The reason is that the light reflected from the lens surface on the light incident side of the cylindrical lens array 4 and returned to the box 3 is not reflected by the outer surface 3h of the box 3 to disturb the directivity. This is because the light that has returned to is absorbed by the outer surface 3h.

  As shown in FIG. 1, the cylindrical lens array 4 is an optical member composed of a plurality of cylindrical lenses 7 (unit lenses). The cylindrical lens array 4 has a configuration in which four cylindrical lenses 7 having the same size and shape are arranged at the same pitch. The thickness direction of the cylindrical lens 7, that is, the z-axis direction is a light transmission direction and is an optical axis direction. The cylindrical lens 7 includes a lens surface that has a curvature in the x-axis direction (first direction) and does not have a curvature in the y-axis direction (second direction).

  As shown in FIG. 4, the cylindrical lens 7 is a biconvex lens having two convex lens surfaces when viewed in a section cut along the xz plane. Thus, for example, when parallel light is incident on the cylindrical lens 7, the light is focused in a cross section cut by the xz plane, that is, in the x-axis direction. On the other hand, as shown in FIG. 5, the cylindrical lens 7 is a rod-like body having a flat surface along the y-axis direction when viewed in a section cut along the yz plane. Thus, for example, when parallel light is incident on the cylindrical lens 7, the light remains parallel light in the cross section cut by the yz plane, that is, in the y-axis direction. When viewed from the optical axis direction of the cylindrical lens array 4, as shown in FIG. 2, the cylindrical lens array 4 is arranged so that a straight line FL in which the focal points of the cylindrical lenses 7 are aligned overlaps the opening 6. .

  As shown in FIG. 4, when the xz cross section of the cylindrical lens array 4 and the box 3 is viewed, the cylindrical lens 7 has the focal point F of the cylindrical lens 7 coincident with the position of the opening 6 corresponding to the cylindrical lens 7. Are arranged as follows. That is, the focal point F of the cylindrical lens 7 is located inside the opening 6 corresponding to the cylindrical lens 7. The light L guided in the cavity 5 reaches the opening 6 after being reflected by the various inner surfaces 3 i of the box 3 a plurality of times. Therefore, the light L is emitted from the opening 6 at various angles. Regardless of the angle at which the light L is emitted from the opening 6, if the diameter D of the opening 6 is small to some extent, only the light L emitted from the focal point F of the cylindrical lens 7 or the vicinity thereof is incident on the cylindrical lens 7. . Thereby, the light L incident on the cylindrical lens 7 at various angles is converted into light substantially parallel to the optical axis AX of the cylindrical lens 7 and is emitted from the cylindrical lens 7.

  On the other hand, as shown in FIG. 5, when the yz cross section of the cylindrical lens array 4 and the box 3 is viewed, the opening 6 is long along the y-axis direction. It passes through 6 different positions and is injected into the external space at various angles. Thereafter, the light L emitted from the box 3 passes through the cylindrical lens array 4. At this time, since the cylindrical lens 7 has no curvature in the y-axis direction and has no focal point, the light L is emitted from the cylindrical lens 7 at various angles without being collimated.

  In the surface light source device 1 of the present embodiment, the light L is extracted only from the opening 6 of the box 3. Therefore, in the x-axis direction, light L that is substantially parallel to the optical axis AX of the cylindrical lens 7, that is, light L with high directivity is obtained by the action of the cylindrical lens 7 having the focal point F at the position of the opening 6. Can do. On the other hand, in the y-axis direction, since the cylindrical lens 7 does not have a lens action, directivity cannot be obtained. That is, according to the present embodiment, the surface light source device 1 having uniaxial directivity can be realized.

  Since the light L emitted from the opening 6 of the box 3 is repeatedly reflected inside the cavity 5, the luminance distribution at the time when the light L is emitted from the narrow opening 6 in the x-axis direction. Is uniformized. As a result, the surface light source device 1 that has passed through the cylindrical lens array 4 can obtain light having a uniform luminance distribution at least in the x-axis direction.

  However, since the light L is emitted from the wide opening 6 in the y-axis direction, the central part of the opening 6 near the LED 2 tends to be bright and the end of the opening 6 far from the LED 2 tends to be dark. . For this reason, it is difficult to make the luminance distribution uniform in the y-axis direction. In order to easily make the luminance distribution uniform in the y-axis direction, for example, a plurality of LEDs 2 may be arranged in the y-axis direction. Alternatively, the thickness (dimension in the z-axis direction) of the box 3 may be increased.

  In the present embodiment, the LED 2 is installed on the bottom plate 3 b of the box 3, but the light L from the LED 2 only needs to enter the cavity 5, so the installation position of the LED 2 is not necessarily limited to the bottom plate 3 b of the box 3. . For example, the LED 2 can be installed on the top plate 3a and the side plates 3c and 3d of the box 3. Thus, in the case of the surface light source device 1 of this embodiment, the freedom degree of the installation position of LED2 is high.

  In the present embodiment, an example is shown in which the same cylindrical lenses 7 and openings 6 are regularly arranged at a uniform pitch. However, if the focal point F of the cylindrical lens 7 is arranged so as to coincide with the position of the opening 6 corresponding to the cylindrical lens 7, the same cylindrical lens 7 and the opening 6 are not necessarily arranged regularly. May be. For example, the cylindrical lenses 7 and the openings 6 having different dimensions may be arranged at different pitches. The box 3 is not necessarily a rectangular parallelepiped, and the two opposing plates are not necessarily parallel.

[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described with reference to FIGS.
FIG. 7 is a plan view of the surface light source device of the second embodiment. 8 is a cross-sectional view taken along the line BB ′ of FIG.
The basic configuration of the surface light source device of the second embodiment is the same as that of the first embodiment, and the configuration of the opening of the box is different from that of the first embodiment.
In FIG. 7 and FIG. 8, the same components as those in FIG. 2 and FIG. 3 of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  As described in the first embodiment, it is difficult to make the luminance distribution uniform in the y-axis direction along the longitudinal direction of the opening. As one means for making the luminance distribution uniform in the y-axis direction, as shown in FIGS. 7 and 8, in the surface light source device 11 of the second embodiment, a series of long openings 6 as in the first embodiment. Instead, a plurality of openings 12a to 12c in a form in which the opening 6 of the first embodiment is divided in the longitudinal direction are provided side by side in the y-axis direction. The plurality of openings 12a to 12c have the same width in the x-axis direction, the length in the y-axis direction is short at the center, and becomes longer toward the end. The point that LED2 is arrange | positioned in the center of the baseplate 3b is the same as that of 1st Embodiment.

  When the LED 2 is arranged at the center of the box 3, the long opening 6 as in the first embodiment has a large amount of light emitted from the center of the opening 6 close to the LED 2, and the opening far from the LED 2. The amount of light emitted from the end of the portion 6 is reduced. In contrast, in the surface light source device 11 of the present embodiment, the opening area of the opening 12a near the center is small and the opening area of the opening 12c near the end is large, so that the LED 2 is arranged in the center. In this case, the unevenness of the emitted light amount, which is that the emitted light amount is large at the central opening and the emitted light amount is small at the end opening, is offset. As a result, the amount of light emitted from the openings 12a to 12c is averaged in the arrangement direction (y-axis direction) of the openings 12a to 12c.

  According to the present embodiment, the surface light source device 11 having uniaxial directivity, high light utilization efficiency, and high uniformity of luminance distribution can be realized.

[Third Embodiment]
Hereinafter, a third embodiment of the present invention will be described with reference to FIG.
FIG. 9 is a plan view of the surface light source device of the third embodiment.
The basic configuration of the surface light source device of the third embodiment is the same as that of the first embodiment, and the configuration of the opening of the box is different from that of the first embodiment.
In FIG. 9, the same components as those in FIG. 2 of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  As another means for making the luminance distribution uniform in the y-axis direction, as shown in FIG. 9, in the surface light source device 21 of the third embodiment, a plurality of openings 22 are arranged in the y-axis direction. Yes. The plurality of openings 22 are all configured with openings of the same size. However, the arrangement density of the openings 22 is such that the pitch between the openings 22 is wide at the center, and the pitch between the openings 22 is narrower toward the end. In other words, the openings 22 on the center side are arranged sparsely, and the openings 22 on the end side are arranged densely. The point that LED2 is arrange | positioned in the center of the baseplate 3b is the same as that of 1st Embodiment.

  When the LED 2 is arranged at the center of the box 3, the long opening 6 as in the first embodiment has a large amount of light emitted from the center of the opening 6 close to the LED 2, and the opening far from the LED 2. The amount of light emitted from the end of the portion 6 is reduced. On the other hand, in the surface light source device 21 of the present embodiment, the LED 2 is arranged in the center because the opening 22 near the center is sparse and the openings 22 near the end are arranged densely. In addition, the unevenness of the emitted light quantity, which is large at the opening on the center side and small at the opening part on the end side, is offset. As a result, the amount of light emitted from the openings 22 is averaged in the arrangement direction (y-axis direction) of the openings 22.

  According to the present embodiment, a surface light source device having uniaxial directivity, high light utilization efficiency, and high luminance uniformity can be realized.

  In the surface light source devices 1, 11, and 21 of the first to third embodiments, the biconvex cylindrical lens 7 is used, but instead of the cylindrical lens 7, the cylindrical lenses shown in FIGS. 10A to 10C are used. A lens may be used.

A cylindrical lens 25 shown in FIG. 10A is a plano-convex cylindrical lens of a lens refraction type in which the light L exit side is a curved surface having a curvature and the incident side is a flat surface.
A cylindrical lens 26 shown in FIG. 10B is a reflection-type planoconvex cylindrical lens in which the incident side of the light L is a curved surface having a curvature and the emission side is a flat surface.
A cylindrical lens 27 shown in FIG. 10C is a hybrid cylindrical lens having both a lens refraction method and a reflection method.

[Fourth Embodiment]
Hereinafter, a fourth embodiment of the present invention will be described with reference to FIGS.
In the fourth embodiment, an example of a liquid crystal display device using the surface light source devices of the first to third embodiments will be described. The liquid crystal display device of this embodiment is intended to prevent the frame area from being seen by the user.
FIG. 11 is a plan view of the liquid crystal display device of the fourth embodiment. 12 is a cross-sectional view taken along the line AA ′ of FIG. FIG. 13 is a perspective view of a surface light source device used in the liquid crystal display device of the present embodiment. FIG. 14 is a diagram showing a simulation result of the light deflection characteristics of the prism sheet used in the liquid crystal display device of the present embodiment. FIG. 15 is a diagram for explaining the action of the light bending sheet used in the liquid crystal display device of the present embodiment.

  As shown in FIG. 12, the liquid crystal display device 31 of this embodiment includes a backlight 32, a prism sheet 33 (first light deflection element), a liquid crystal panel 34, a pair of polarizing plates 35a and 35b, and a pair. Viewing angle compensation films 36a and 36b, a light bending film 37 (second light deflection element), and a light scattering film 38. The liquid crystal panel 34 includes a pair of glass substrates 40 a and 40 b that sandwich the liquid crystal layer 39. The liquid crystal panel 34 is a display element that performs display using light emitted from the backlight 32. The liquid crystal panel 34 includes a display area R1 at the center of the screen and a frame area R2 surrounding the display area.

  The prism sheet 33 is provided between the cylindrical lenses 7A, 7B, and 7C of the backlight 32 and the incident side polarizing plate 35a. The prism sheet 33 deflects the traveling direction of the light L emitted from the cylindrical lenses 7 </ b> A, 7 </ b> B, 7 </ b> C toward the peripheral portion of the liquid crystal panel 34. The light bending film 37 is provided on the front side (light emission side) of the liquid crystal panel 34. The light bending film 37 deflects the traveling direction of the light L deflected by the prism sheet 33 in the normal direction of the display surface of the liquid crystal panel 34 after passing through the peripheral portion of the liquid crystal panel 34.

  As shown in FIG. 13, the backlight 32 is a combination of a first surface light source device 41 for an omnidirectional region and second surface light source devices 42, 43, 44 for a uniaxial directivity region. It has a configuration. One first surface light source device 41 is arranged at the center of the screen, and eight second surface light source devices 42, 43, 44 are arranged at the periphery of the screen so as to surround the first surface light source device 41. Has been. The surface light source device of the first embodiment is employed for the second surface light source devices 42, 43, 44.

  As shown in FIGS. 11, 12, and 13, the second surface light source devices 42, 43, and 44 include box bodies 3 </ b> A, 3 </ b> B, and 3 </ b> C having slit-like openings 6 and box bodies 3 </ b> A, 3 </ b> B, and 3 </ b> C. LED 2 provided on the bottom plate of the lens, and cylindrical lenses 7A, 7B, 7C provided corresponding to the openings 6A, 6B, 6C above the boxes 3A, 3B, 3C. In FIG. 13, the cylindrical lenses 7A, 7B, and 7C are not shown for easy viewing of the configuration of the box.

  Of the eight second surface light source devices 42, 43, and 44, for the two second surface light source devices 42 arranged in parallel to the x-axis direction, the box 3A has an opening extending in the x-axis direction. Part 6A. Correspondingly, the cylindrical lens 7A includes a lens surface having a curvature in the y-axis direction and having no curvature in the x-axis direction. The cylindrical lens 7A is arranged so that the longitudinal direction thereof coincides with the x-axis direction, and a straight line formed by aligning the focal points of the cylindrical lens 7A overlaps the opening 6A.

  Similarly, for the two second surface light source devices 43 arranged in parallel with the y-axis direction, the box 3B has an opening 6B extending in the y-axis direction. Correspondingly, the cylindrical lens 7B has a lens surface having a curvature in the x-axis direction and no curvature in the y-axis direction. The cylindrical lens 7B is arranged so that the longitudinal direction thereof coincides with the y-axis direction, and a straight line formed by aligning the focal points of the cylindrical lens 7B overlaps the opening 6B.

  For the four second surface light source devices 44 arranged at the four corners of the backlight 32, the box 3C has an opening 6C that forms an angle of 45 ° with respect to the x-axis direction and the y-axis direction. have. Correspondingly, the cylindrical lens 7C has a lens surface having a curvature in a direction perpendicular to the extending direction of the opening 6C and having no curvature in a direction parallel to the extending direction of the opening 6C. A straight line formed by aligning the focal points of the cylindrical lens 7C overlaps the opening 6C.

  As shown in FIG. 12, the prism sheet 33 includes a plurality of prisms 45. The prism 45 includes a light-transmitting convex portion that extends in a direction parallel to the extending direction of the openings 6A, 6B, and 6C. The cross-sectional shape cut by a plane perpendicular to the extending direction of the prism 45 is a substantially right triangle. The first side surface 45 c constituting the prism 45 is perpendicular to the bottom surface 33 b of the prism sheet 33, and the second side surface 45 d forms an angle of 60 ° with respect to the bottom surface 33 b of the prism sheet 33. Accordingly, the apex angle formed by the first side surface 45c and the second side surface 45d is 30 °.

  The light L incident from the bottom surface 33b of the prism sheet 33 is reflected by the second side surface 45d, changes its traveling direction, and is emitted from the first side surface 45c. The prism sheet 33 is disposed such that the first side surface 45 c faces the outside of the liquid crystal display device 31 and the second side surface 45 d faces the inside of the liquid crystal display device 31. FIG. 12 shows only the prism sheet 33 corresponding to the second surface light source device 43 arranged in parallel to the y-axis direction, but the second surface light source device arranged in parallel to the x-axis direction. 42 and the second surface light source device 44 arranged at the corner are also provided with a similar prism sheet.

  The 1st surface light source device 41 is provided with box 3D which has circular opening part 6D, and LED2 provided in the baseplate of box 3D. As shown in FIG. 11, a plurality of (for example, 64) circular openings 6D are provided on the top plate of the box 3D, and the 64 openings 6D are regularly arranged in 8 rows × 8 columns. Yes. In FIG. 12, the number of openings 6D is reduced to make the drawing easier to see. However, the shape of the opening 6D is not limited to a circle, and the number and arrangement of the openings 3D are not particularly limited to this embodiment. Unlike the second surface light source devices 42, 43, and 44, the first surface light source device 41 does not include a cylindrical lens and a prism sheet.

  As shown in FIG. 11, in the liquid crystal panel 34, areas for arranging the lead wiring drawn from the display area R <b> 1 are provided on the four sides of the peripheral portion, and the layout areas for the lead wiring are shielded by the black matrix 46. . Therefore, the layout area of the routing wiring shielded by the black matrix 46 is a frame area R2 that does not directly contribute to display. The width W of the frame region R2 is about 2 mm, for example.

  As the liquid crystal panel 34, for example, an active matrix transmissive liquid crystal panel can be used. However, the liquid crystal panel is not limited to the active matrix transmissive liquid crystal panel. For example, a transflective (transmissive / reflective) liquid crystal panel does not include a switching thin film transistor (hereinafter abbreviated as TFT). A simple matrix type liquid crystal panel may be used. Since a well-known general liquid crystal panel can be used for the liquid crystal panel 34, detailed description of a structure is abbreviate | omitted. The liquid crystal display mode may be any of TN mode, VA mode, horizontal electric field mode, and the like, and is not particularly limited.

As shown in FIG. 12, the light bending film 37 includes a base material 48, a plurality of structures 49, and a light shielding layer 50. The plurality of structures 49 are formed on the upper surface (surface on the viewing side) of the base material 48 at a predetermined interval. A gap 51 is provided between the adjacent structures 49, and air exists in the gap 51. The light shielding layer 50 is formed in a region other than the region where the structure 49 is formed on the upper surface of the substrate 48. The lower surface (rear surface) of the substrate 48 faces the upper surface of the exit-side polarizing plate 35b.
The light bending film 37 is disposed on the emission side polarizing plate 35b in such a posture that the base material 48 side is directed to the emission side polarizing plate 35b and the side on which the structure 49 is provided is directed to the viewing side.

  As the base material 48, generally, a thermoplastic polymer, a thermosetting resin, a resin such as a photopolymerizable resin, or the like is used, and a light-transmitting base material is preferably used. In this embodiment, a PET film having a thickness of 20 μm is used as an example. The structure 49 is made of an organic material having optical transparency and photosensitivity such as an acrylic resin, an epoxy resin, or a silicone resin. In this embodiment, a photosensitive acrylic resin having a thickness of 20 μm is used as an example. A mixture made of a transparent resin in which a polymerization initiator, a coupling agent, a monomer, an organic solvent and the like are mixed with these resins can be used. Further, the polymerization initiator may contain various additional components such as a stabilizer, an inhibitor, a plasticizer, a fluorescent brightening agent, a mold release agent, a chain transfer agent, and other photopolymerizable monomers. .

  Each of the plurality of structures 49 has a light incident end surface on the base material 48 side and a light emission end surface on the opposite side to the base material 48 side. The plurality of structures 49 include a first structure 49 </ b> A located at the central portion of the base material 48 and a plurality of second structures 49 </ b> B located at the peripheral edge of the base material 48. The first structure 49 </ b> A is formed in a block shape at the center of the base material 48 using a light transmissive material. The second structure 49B is formed of a light transmissive material at a predetermined interval around the periphery of the base material 48. The side surface in contact with the gap 51 of the second structure 49B is inclined toward the outside of the light incident end surface. The side surface is a surface that reflects light emitted in an oblique direction from the liquid crystal panel 34 toward the normal direction of the liquid crystal panel 34. The area of the light incident end face is approximately equal to the area of the light exit end face.

  The inclination angle α (angle formed between the light emission end face and the side surface) of the side surface of the second structure 49B is about 76 ° as an example. However, the inclination angle α of the side surface of the second structure 49B is not particularly limited as long as the incident light can be bent in the normal direction of the liquid crystal panel 34 when emitted from the light bending film 37. . In the present embodiment, the inclination angle α of the side surface of the second structure 49B is constant.

  The light bending film 37 totally reflects the light L, which is transmitted through the liquid crystal panel 34 and obliquely incident on the lower surface of the base material 48, on the side surface of the second structure 49 </ b> B and is viewed from the normal direction of the base material 48. Is converted into light having a light distribution that maximizes the luminance of the light.

  Air exists in the gap 51, and the refractive index is approximately 1.0. By setting the refractive index of the gap 51 to 1.0, the critical angle at the interface between the gap 51 and the structure 49 is minimized. In the present embodiment, air exists in the gap 51, but is not limited to air. For example, an inert gas such as nitrogen may be present in the gap 51, and the gap 51 may be in a reduced pressure state.

  The light shielding layer 50 is formed on the upper surface of the base material 48 with a thickness smaller than the height of the structure 49. For example, the thickness of the light shielding layer 50 is 1 μm. As an example, the light shielding layer 50 is made of an organic material having light absorption and photosensitivity such as black resist and black ink. In addition, a metal film such as Cr (chromium) or a Cr / Cr oxide multilayer film may be used.

  The light scattering film 38 is provided on the side opposite to the base material 48 with the structure 49 interposed therebetween. The light scattering film 38 has light transmittance, and a plurality of scattering particles that scatter visible light are dispersed inside the binder resin. As the binder resin, for example, an acrylic resin or the like is used. As scattering particles, for example, acrylic beads are used. The light scattering film 38 is fixed to the light emission end faces of the plurality of structures 49 with an optical adhesive or the like.

  11 schematically represent the orientation distribution of light emitted from the first surface light source device 41 or the second surface light source devices 42, 43, and 44 constituting the backlight 32. It is shown. Since the cylindrical lenses 7A, 7B, and 7C and the prism sheet 33 do not exist on the light emission side of the first surface light source device 41, the orientation distribution of the light emitted from the first surface light source device 41 has directivity. do not have. Therefore, the orientation distribution F22 viewed from the light emission side is circular. The second surface light source devices 42 and 43 arranged along the four sides of the liquid crystal display device 31 have directivity in a direction perpendicular to each side, and no directivity in a direction parallel to each side. Shows uniaxial directivity. Accordingly, the orientation distributions F12, F32, F21, and F23 viewed from the light emission side are elliptical and flat in a direction perpendicular to each side. The second surface light source device 44 arranged along the four corners of the liquid crystal display device 31 connects the inner side and the outer side of the liquid crystal display device 31 in two directions forming an angle of 45 ° with each side. Unidirectional directivity with no directivity in the direction orthogonal to the direction is shown. Therefore, the orientation distributions F11, F13, F31, and F33 viewed from the light exit side are elliptical and flat in a direction that forms an angle of 45 ° with respect to each side.

  As shown in FIG. 12, in the peripheral part of the liquid crystal display device 31, it has the light L parallelized with respect to the direction perpendicular | vertical to each edge | side from the 2nd surface light source devices 42 and 43, ie, uniaxial directivity. Light L is emitted. The light L having uniaxial directivity is incident on the prism sheet 33 and reflected by the second side surface 45d of each prism 45, whereby the traveling direction of the light L is bent.

  FIG. 14 shows the result of simulation performed by the present inventors and shows the light deflection action of the prism sheet 33. As described above, the second side surface 45d of the prism 45 forms an angle of 60 ° with respect to the bottom surface 33b of the prism sheet 33, and the refractive index of the prism 45 is 1.5. At this time, the traveling direction of the light L reflected by the second side surface 45 d of the prism 45 and emitted from the first side surface 45 c forms an angle of 42 ° with respect to the normal direction of the prism sheet 33.

  Therefore, the light L emitted from the prism sheet 33 enters the liquid crystal panel 34 at an incident angle of 42 °. Even if the light L passes through the liquid crystal panel 34 and is refracted at each interface between substances, the incident angle is preserved, so that the light L also enters the liquid crystal panel 34 at an incident angle of 42 °. Here, assuming that the width W of the frame region R2 is 2 mm, the traveling direction of light obliquely passing through the inner edge of the frame region R2 of the liquid crystal panel 34 in order to hide the frame region R2 from the observer. Is bent by the light-bending film 37 so that it looks as if it is emitted from the outer edge of the frame region R2 to the eyes of the observer.

  As shown in FIG. 15, the distance between the pixel of the liquid crystal panel 34 and the light bending film 37 is d, the incident angle θ1 is 42 °, and a substance (for example, acrylic resin) interposed between the pixel of the liquid crystal panel 34 and the light bending film 37. When the refractive index of the resin is 1.5, the incident angle θ2 from the intervening material to the light bending film 37 is 30 °. At this time, since the width W of the frame region R2 is 2 mm, the distance d between the pixel of the liquid crystal panel 34 and the light bending film 37 can be calculated as 3.5 mm. In this case, the pixel of the liquid crystal panel 34 is considered to be at the position of the liquid crystal layer 39.

  Between the pixel of the liquid crystal panel 34 and the light bending film 37, for example, a glass substrate 40b having a thickness of 0.7 mm, a viewing angle compensation film 36b, and an exit-side polarizing plate 35b exist, and the total thickness is about 1 mm. Have In this case, in order to set the distance d between the pixel of the liquid crystal panel 34 and the light bending film 37 to 3.5 mm, an acrylic resin having a thickness of 2.5 mm is provided between the emission side polarizing plate 35 b and the light bending film 37. A plate may be inserted and optically bonded. As a result, the image displayed by the pixel at the position of the symbol H is displayed at the position of the symbol H ′ on the outermost surface of the liquid crystal display device 31, and the viewer visually recognizes the frame region G2 having a width W of 2 mm. become unable. In this way, the frame area G2 of the liquid crystal display device 31 can be made invisible. In addition, since the optical member (the prism sheet 33 and the second structure 49B) for bending the light traveling direction is disposed only at the peripheral portion of the liquid crystal display device 31, image distortion can be reduced.

  If the material interposed between the pixel of the liquid crystal panel 34 and the light bending film 37 is air instead of acrylic resin, for example, the incident angle θ2 from the interposed material to the light bending film 37 is 42 °. In that case, the frame region R2 having a smaller thickness and a width W of 2 mm can be made invisible.

[Fifth Embodiment]
Hereinafter, a fifth embodiment of the present invention will be described with reference to FIG.
The basic configuration of the liquid crystal display device of the fifth embodiment is the same as that of the fourth embodiment, and the configuration of the light bending film is different from that of the fourth embodiment.
FIG. 16 is a cross-sectional view of the liquid crystal display device of the fifth embodiment.
In FIG. 16, the same components as those in FIG. 12 of the fourth embodiment are denoted by the same reference numerals, and description thereof is omitted.

  In the liquid crystal display device 54 of the present embodiment, as shown in FIG. 16, the light L incident on the liquid crystal panel 34 from the prism sheet 33 has an angle formed between the optical axis and the normal direction of the liquid crystal panel 34. It gradually increases from the central part toward the peripheral part. Accordingly, the inclination angles α1, α2, and α3 of the side surfaces of the second structures 49B, 49C, and 49D of the light bending film 55 are gradually decreased from the central portion toward the peripheral portion of the liquid crystal panel 34.

  Also in the present embodiment, it is possible to realize a liquid crystal display device in which the frame region R2 is not visible and the overall image distortion is small. However, in the liquid crystal display device 31 of the fourth embodiment, there is an image at the boundary between the first structure 49A and the second structure 49B of the light bending film 37, that is, the boundary between the omnidirectional area and the uniaxial directional area. The distortion of is easy to stand out. On the other hand, in the liquid crystal display device 54 of the present embodiment, since the inclination of the optical axis changes gently from the center to the periphery of the screen, the image distortion becomes continuous and a more natural image can be obtained. Easy to display.

[Sixth Embodiment]
Hereinafter, a sixth embodiment of the present invention will be described with reference to FIG.
The basic configuration of the liquid crystal display device of the sixth embodiment is the same as that of the fourth embodiment, and is different from the fourth embodiment in that no light bending film is provided.
FIG. 17 is a cross-sectional view of the liquid crystal display device of the sixth embodiment.
In FIG. 17, the same components as those in FIG. 12 of the fourth embodiment are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 17, the liquid crystal display device 58 of the present embodiment has a configuration in which the light bending film 37 is removed from the liquid crystal display device 31 of the fourth embodiment shown in FIG. In other words, in the liquid crystal display device 58 of the present embodiment, the light scattering film 38 is provided on the upper surface of the exit side polarizing plate 35 b of the liquid crystal panel 34.

  In this configuration, the light L that has passed obliquely inside the frame region R2 of the liquid crystal panel 34 is scattered by the light scattering film 38 when it reaches the outside of the frame region R2. Therefore, when the observer is positioned in front of the liquid crystal display device 58, a part of the light scattered by the light scattering film 38 enters the eyes of the observer, so that the frame region R2 cannot be seen by the observer. .

  Also in this embodiment, it is possible to realize the liquid crystal display device 58 in which the frame area is not visible and the overall image distortion is small. Further, in the case of the liquid crystal display device 58 of the present embodiment, the image can be seen in a wide range from a wider angle range by providing the light scattering film 38 with high diffusibility.

  Note that the backlight 32 used in the fourth to sixth embodiments is composed of nine surface light source devices in which the boxes 3A, 3B, 3C, and 3D are independent, but the boxes are not necessarily independent. There may not be, and the whole may be united.

[Seventh Embodiment]
The seventh embodiment of the present invention will be described below with reference to FIGS.
In the seventh embodiment, an example of a liquid crystal display device using the surface light source devices of the first to third embodiments will be described. The liquid crystal display device of this embodiment is intended to improve pixel transmittance.

  FIG. 18 is a perspective view of the liquid crystal display device of the seventh embodiment. FIG. 19 is a cross-sectional view taken along line A-A ′ of FIG. 18. 20A is an equivalent circuit diagram showing a part of a TFT substrate constituting the liquid crystal display device, and FIG. 20B is a plan view of a pixel of the TFT substrate. FIG. 21A is a diagram showing a simulation model demonstrating the effect of the present embodiment, FIG. 21B is a diagram showing a luminance distribution of a uniaxial directional light source used for the simulation, and FIG. It is a top view of the pixel used for simulation. 22A to 22C are diagrams illustrating simulation results when the luminance distribution of the uniaxial directional light source is changed in three ways.

  As shown in FIGS. 18 and 19, the liquid crystal display device 61 of the present embodiment includes a backlight 62, a microlens array 63, a liquid crystal panel 34, a pair of polarizing plates 35a and 35b, and a pair of viewing angle compensation films. 36a, 36b and a light scattering film 38. The liquid crystal panel 34 is an active matrix liquid crystal panel including a thin film transistor (hereinafter abbreviated as TFT) array substrate 64 and a counter substrate 65 that sandwich a liquid crystal layer 39. The liquid crystal panel 34 is a display element that performs display using light emitted from the backlight 62.

  As the backlight 62, the surface light source device of the first embodiment can be used. In the example of FIGS. 18 and 19, seven openings 6 are provided in the top plate 3 a of the box 3, and the cylindrical lens array 4 including the seven cylindrical lenses 7 is provided correspondingly. However, the number of openings 6 and the number of cylindrical lenses 7 are not limited to this.

  Of the two substrates constituting the liquid crystal panel 34, the TFT array substrate 64 is disposed on the backlight 62 side, and the counter substrate 65 is disposed on the viewing side. As shown in FIG. 20A, in the TFT array substrate 64, a plurality of gate bus lines 66 and a plurality of data bus lines 67 are provided orthogonal to each other. A region surrounded by adjacent gate bus lines 66 and adjacent data bus lines 67 is one pixel 68. Therefore, the TFT array substrate 64 has a plurality of pixels 68 arranged in a matrix. A TFT 69 is provided in each of the plurality of pixels 68, and the gate bus line 66 and the data bus line 67 are electrically connected to the pixel electrode 70 through the TFT 69.

  In the TFT array substrate 64, the region where the gate bus line 66, the data bus line 67, the TFT 69, the additional capacitor (not shown) and the like are formed is shielded from light by a lattice-like light shielding film. Hereinafter, the lattice-shaped light shielding film is referred to as a black matrix. FIG. 20B shows a black matrix 71 for one pixel. Of the rectangular pixel 68, the region other than the black matrix 71 is a light transmission region RT that contributes to display. For example, in the case of a 60-inch full high-definition TV, the ratio of the light transmission region 68 in the pixel 68, that is, the transmittance is about 70%.

In the future, it is expected that the area of the pixel will become smaller as the liquid crystal display device is further refined. For example, in FIG. 20B, when the area is reduced from the pixel 68 to the pixel 68 ′, the width of the black matrix 71 along the gate bus line 66 may be reduced as the TFT 69 and the additional capacitance are reduced. . On the other hand, the width of the black matrix 71 along the data bus line 67 is limited in reduction due to restrictions in the manufacturing process. That is, W _G 1> W _G 2 and W _S 1 = W _S 2 may be satisfied. In such a case, the area of the pixel 68 ′ is reduced as the definition is increased, and the shape of the light transmission region T ′ is a more elongated rectangle. In this case, in order to improve the pixel transmittance, a backlight having a uniaxial directivity in which the directivity in the direction along the gate bus line 66 is higher than the directivity in the direction along the source bus line 67 is used. Becomes effective.

  Therefore, in the liquid crystal display device 61 of the present embodiment, as shown in FIG. 19, the backlight 62 composed of the surface light source device of the first embodiment having uniaxial directivity is used, and the directivity direction of the backlight 62 is changed. It is made to correspond to the direction along the gate bus line 66. That is, in FIG. 19, the direction in which the cylindrical lens 7 of the backlight 62 has a curvature is a direction parallel to the paper surface (x-axis direction), and the direction in which the cylindrical lens 7 has no curvature is a direction perpendicular to the paper surface (y-axis). Direction). On the other hand, the direction in which the gate bus line 66 of the liquid crystal panel 34 extends is a direction parallel to the paper surface (x-axis direction), and the direction in which the data bus line 67 extends is a direction perpendicular to the paper surface (y-axis). Direction).

  A microlens array 63 is provided between the backlight 62 and the incident-side polarizing plate 36a. The microlens array 63 includes a plurality of cylindrical microlenses 72 arranged in a matrix. One cylindrical microlens 72 is arranged corresponding to one pixel 68. The direction of the cylindrical microlens 72 is the same as that of the cylindrical lens 7 of the backlight 62, and the direction in which the cylindrical microlens 72 has a curvature is a direction parallel to the paper surface (a direction parallel to the gate bus line 66). The direction in which the lens 72 does not have a curvature is a direction perpendicular to the paper surface (a direction parallel to the data bus line 67). The position of the focal point of the cylindrical microlens 72 substantially matches the position of the opening (light transmission region T) of the black matrix 71. The cylindrical microlens 72 may be provided integrally with a plurality of pixels 68 arranged in a direction parallel to the data bus line 67 or may be divided for each pixel 68.

  As described in the first embodiment, the light L that is parallelized in the direction in which the cylindrical lens 7 has a curvature is emitted from the backlight 62 and is incident on the liquid crystal panel 34. At this time, the light L that has been collimated in one direction is focused on the position of the opening of the black matrix 71 by each cylindrical microlens 72 of the microlens array 63, passes through the opening, and is diffused and emitted again. . The light L is scattered by the light scattering film 38 on the outermost surface, and the viewing angle is further expanded. Thereby, the observer can visually recognize an image. The light scattering film 38 is not necessarily provided.

  As described above, according to the liquid crystal display device 61 of the present embodiment, the backlight 62 having uniaxial directivity that matches the shape of the light transmission region T of the pixel 68 of the liquid crystal panel 34 is used. The light L is condensed on the light transmission region T by the microlens array 63. Thereby, the light use efficiency per pixel can be improved, and a liquid crystal display device capable of obtaining a bright image can be realized.

The inventors performed a simulation for verifying the effect of the liquid crystal display device 61 of the present embodiment. The result will be described.
As a simulation model, as shown in FIG. 21A, light from a virtual uniaxial directional light source 74 is condensed by a cylindrical microlens 75, and at a position S away from the cylindrical microlens 75 by a distance t. The illuminance distribution was determined. Based on the illuminance distribution, the light transmittance in the black matrix at the position S separated from the cylindrical microlens 75 by the distance t was calculated.

  In the simulation, assuming a 60-inch Super Hi-Vision TV, as shown in FIG. 21C, the horizontal dimension PX1 (direction parallel to the gate bus line) of the pixel PX is 58 μm, and the vertical dimension PX2 of the pixel PX. The direction (parallel to the data bus line) was 173 μm, the horizontal dimension T1 of the light transmission region T was 23 μm, and the vertical dimension T2 of the light transmission region T was 105 μm. At this time, the aperture ratio of the pixel PX is 24%.

The dimension of the uniaxial directional light source 74 was the same as the dimension of the pixel PX. The orientation distribution of the uniaxial directional light source 74 is as shown in FIG. 21B, and the amount of light emitted to the wide angle side in the top hat type is zero.
The thickness d of the cylindrical microlens 75 was several μm, and the distance t from the cylindrical microlens 75 to the position S for obtaining the illuminance distribution was 500 μm.
The side surface SP1 of the space SP is a light reflecting surface.

22A to 22C show simulation results of illuminance distribution.
22A shows the illuminance distribution when the full width at half maximum (FWHM) of the light source luminance distribution is 0 °, and FIG. 22B shows the illuminance distribution when the FWHM of the light source luminance distribution is 5 °, FIG. 22C shows the illuminance distribution when the FWHM of the light source luminance distribution is 10 °. It can be seen that the illuminance distribution spreads in the order of FIGS. 22 (A), 22 (B), and 22 (C).
When the FWHM of the light source luminance distribution in FIG. 22A is 0 °, the ratio of light entering the light transmission region T is 59%. When the FWHM of the light source luminance distribution in FIG. 22B is 5 °, the proportion of light entering the light transmission region T is 45%. When the FWHM of the light source luminance distribution in FIG. 22C is 10 °, the ratio of light entering the light transmission region T was 28%.

  Thus, it was found that the smaller the FWHM of the light source luminance distribution, the greater the proportion of light entering the light transmission region T. From this simulation result, it was found that the light use efficiency per pixel is increased as the directivity of the surface light source device is increased.

[Eighth Embodiment]
The eighth embodiment of the present invention will be described below with reference to FIG.
The basic configuration of the liquid crystal display device of the eighth embodiment is the same as that of the seventh embodiment, and the position of the microlens array is different from that of the seventh embodiment.
FIG. 23 is a cross-sectional view of the liquid crystal display device of the eighth embodiment.
In FIG. 23, the same components as those in FIG. 19 of the seventh embodiment are denoted by the same reference numerals, and description thereof is omitted.

  In the liquid crystal display device 61 of the seventh embodiment, the microlens array 63 is provided outside the incident side polarizing plate 35a. On the other hand, in the liquid crystal display device 81 of the eighth embodiment shown in FIG. 23, the microlens array 63 is provided between the liquid crystal panel 34 and the viewing angle compensation film 36a. Other configurations are the same as those of the liquid crystal display device 61 of the seventh embodiment.

  Also in the present embodiment, the same effects as those of the seventh embodiment can be obtained in that the light use efficiency per pixel is improved and a liquid crystal display device capable of obtaining a bright image can be realized.

[Configuration example of display device]
Hereinafter, a configuration example of the display device will be described with reference to FIG.
FIG. 24 is a front view illustrating a schematic configuration of a liquid crystal display device which is a configuration example of the display device.

As shown in FIG. 24, the liquid crystal television 193 of this configuration example includes the liquid crystal display devices of the fourth to eighth embodiments as a display screen 194. A liquid crystal panel is disposed on the viewer side (front side in FIG. 24), and a backlight (surface light source device) is disposed on the side opposite to the viewer (back side in FIG. 24).
Since the liquid crystal television 193 of this configuration example includes the liquid crystal display device of the above-described embodiment, it is a liquid crystal television capable of high-quality display.

[Ninth Embodiment]
The ninth embodiment of the present invention will be described below with reference to FIG.
In the ninth embodiment, an example of a lighting device including the surface light source device of the first embodiment is shown.
FIG. 25 is a side view showing the lighting apparatus of the present embodiment.
In FIG. 25, the same components as those used in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 25, the illumination device 197 of this embodiment includes the surface light source device of the first embodiment. Therefore, the illumination device 197 of the present embodiment can perform illumination with directivity and a uniform illuminance distribution. For example, it can be used for applications such as indirect lighting that efficiently illuminates only the wall surface of the room. It is also suitable as a lighting device for posters and pictures.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the said 1st-3rd embodiment, although the light transmissive part for taking out light from a box was comprised by the opening part provided in the top plate, the light transmissive part does not necessarily need to be opened. . For example, it may be a light transmissive portion having a configuration in which the opening is closed with a transparent member, and only needs to be able to extract light.

  In the above embodiment, the LED is used as the light source, but a laser or the like may be used. Moreover, it is not restricted to these solid light sources, It is also possible to use other light sources, such as a cold cathode tube. When a plurality of light sources are used as in the above embodiment, the light sources are not necessarily arranged at equal intervals, and the arrangement of the light sources may be sparse / dense. Similarly, the arrangement of the light transmission part and the cylindrical lens is not necessarily equal, and may be densely / sparsely arranged as necessary. Further, it is sufficient that the number of light transmitting portions and cylindrical lenses is at least one. In addition, specific configurations such as the number, arrangement, and material of each component of the surface light source device exemplified in the above embodiment can be changed as appropriate.

  In the liquid crystal display device of the above embodiment, an example using a uniaxial directivity surface light source device has been shown. However, the uniaxial directivity need not necessarily be used, and a surface light source device having directivity in all directions is used. May be. Even in that case, the purpose of making the frame invisible and improving the pixel transmittance can be achieved.

  The present invention is applicable to various display devices such as a liquid crystal display device, an organic electroluminescence display device, and a plasma display.

  DESCRIPTION OF SYMBOLS 1, 11, 21 ... Surface light source device, 2 ... LED (light source), 3, 3A, 3B, 3C, 3D ... Box, 4 ... Cylindrical lens array (lens member), 5 ... Cavity (internal space), 6, 6A, 6B, 6C, 6D, 12a, 12b, 12c, 22 ... opening (light transmission part), 7, 7A, 7B, 7C, 25, 26, 27 ... cylindrical lens (unit lens), 31, 54, 58 , 61, 81 ... liquid crystal display device, 32, 62 ... backlight (surface light source device), 33 ... prism sheet (first light deflection element), 34 ... liquid crystal panel (display element), 37, 55 ... light bending film (Second light deflection element), 63... Microlens array, 71... Black matrix (light-shielding layer), 72.

Claims (5)

A light source;
A light emitting surface having at least one light transmission part, and guiding light incident from the light source while reflecting the light in an internal space, and a box that is emitted from the light transmission part;
A lens member including at least one unit lens on which light emitted from the light exit surface of the box is incident,
The unit lens includes a lens surface having a curvature in at least the first direction out of a first direction and a second direction orthogonal to each other in a virtual plane orthogonal to the optical axis of the unit lens;
A surface light source device, wherein a focal position of the unit lens substantially coincides with a position of the light transmitting portion.   The surface light source device according to claim 1, wherein light transmitted through the unit lens is substantially parallelized in the first direction. The surface light source device according to claim 1 or 2,
A display element for performing display by light emitted from the surface light source device;
A first light deflection element that is provided between the lens member and the display element and deflects the traveling direction of light emitted from the peripheral portion of the lens member toward the peripheral portion of the display element;
The traveling direction of light deflected by the first light deflecting element is provided on the light emitting surface side of the display element, and the normal direction of the display surface of the display element is transmitted through the peripheral edge of the display element. A second optical deflection element for deflecting,
The display device, comprising: a display region; and a frame region located around the display region. The surface light source device according to claim 1 or 2,
A display element that performs display by light emitted from the surface light source device,
The display element includes a lattice-shaped light shielding layer in which a plurality of pixel regions arranged in a matrix are opened in a substantially rectangular shape, and a plurality of lenses that focus light incident from the lens member on the opening of the light shielding layer. A lens array,
The display device characterized in that the first direction substantially coincides with a direction parallel to an arbitrary side of a rectangle forming the planar shape of the opening.   An illuminating device comprising the surface light source device according to claim 1.