JP5311034B2 - Light source device, backlight unit, and display device - Google Patents

Description

  The present invention relates to a light source device used for illumination light path control, a backlight unit using the same, and a display device using the backlight unit. Specifically, the present invention relates to a light source device, a backlight unit, and a display device that emits uniform light without uneven brightness.

In recent years, in a display device such as a large-sized liquid crystal television, a direct type backlight unit in which a plurality of cold cathode tubes, LEDs (Light Emitting Diodes) and the like are arranged as a light source has been adopted. A device illustrated in FIG. 7 is generally known as a liquid crystal display device of a direct type backlight unit. In the case of FIG. 7, a liquid crystal panel 35 sandwiched between polarizing plates 31 and 33 is provided in the upper part, and is emitted from the light source 41 on the lower surface side thereof and diffused by an optical sheet 50 such as a light diffusion plate or a diffusion film. The transmitted light passes through the effective display area of the display screen of the liquid crystal panel 32. In order to efficiently use the light emitted from the light source 41 on the side opposite to the display screen as illumination light, a reflective layer 45 is disposed on the back surface of the light source 41.

In the above-described liquid crystal display device and backlight unit, the light source image is not visually recognized on the display screen, that is, the luminance of the display screen is not uneven due to the location where the light source is disposed and the location where the light source is not disposed. It is necessary to use a light diffusing plate having a strong light diffusing function directly above. In this case, the light diffusion plate is required to have a strong diffusion performance. Therefore, when the thickness of the light diffusion plate is increased (for example, about 5 mm), it is difficult to reduce the thickness of the display device, and the amount of light (total light transmittance) that passes through the effective display area of the display screen is reduced. Occurs. As another method, it is conceivable to increase the amount of light diffusing particles contained in the light diffusing plate. However, in this case as well, there is a problem that the display screen becomes dark as a result because the total light transmittance is significantly reduced. .

Therefore, when a plurality of substantially linear light sources (for example, cold cathode fluorescent lamps) arranged in parallel are used, as shown in Patent Documents 1 and 2, for example, a long prism or By forming a lens or arranging a prism sheet or a lens sheet on the display screen side of the light diffusing plate, a reduction in total light transmittance of the display screen is prevented, and brightness unevenness is prevented from occurring. Such a prism (prism sheet) or lens (lens sheet) plays a role of directing diffused light emitted from the light diffusion plate in a specific direction (for example, a normal direction to the display screen). Therefore, by deflecting the light emitted from between the linear light source and the linear light source in a specific direction, and increasing the light transmittance (that is, indicating the luminance) in the specific direction even in a place where the light source is not disposed. The difference in brightness with the light source is reduced, thereby reducing the brightness unevenness of the entire display screen.

In the case of the above-described substantially linear light source, the luminance of the linear light source is substantially uniform in the longitudinal direction, whereas the location where the light source is disposed in the direction perpendicular to the longitudinal direction is arranged. There are places where this is not done, and uneven brightness tends to occur. Therefore, the luminance unevenness of the entire display screen is reduced by mainly improving the luminance unevenness in the direction perpendicular to the longitudinal direction of the light source. However, in the case of a substantially point light source (such as an LED), the point light sources are two-dimensionally arranged at intervals, and it is necessary to improve luminance unevenness in the two-dimensional direction around the entire light source. Therefore, the luminance unevenness of the entire display screen is more likely to occur. Therefore, for example, a method of increasing the thickness of the light diffusing plate and a method of increasing the number of prism sheets and lens sheets are conceivable. However, it is difficult to reduce the thickness, and the total light transmittance is reduced. Even if is used, luminance unevenness is confirmed.

JP 2007-103321 A JP 2006-195276 A

The present invention has been made in view of the above-described circumstances, and even in a substantially point light source, it is possible to eliminate luminance unevenness of the display screen while preventing a decrease in the total light transmittance of the display screen. An object of the present invention is to provide a light source device capable of reducing the thickness of the device, a backlight unit including the light source device, and a display device.

In order to achieve the above object, the present invention employs the following configuration. That is, the invention of claim 1 includes a plurality of light sources arranged two-dimensionally, a light diffusion member that diffuses light emitted from the light source, and an optical member that controls light emitted from the light diffusion member. And a convex first cylindrical lens formed at a predetermined pitch on the exit surface of the optical member, and a convex second formed in a direction substantially orthogonal to the first cylindrical lens. The area of the region included in the second cylindrical lens on the lens side surface of the first cylindrical lens is 5% or more to the total surface area of the lens side surface. % or less der is, an aspect ratio representing a ratio of height to the lens top relative to the lens width of the first and second cylindrical lenses is 0.3 to 1.0, and the light Haze value of dispersion member is a light source and wherein the 95% or less than 60%.

The invention of claim 2 is a light source apparatus according to claim 1 Symbol mounting, characterized in that the cross section of said first and second cylindrical lens is aspherical.

According to a third aspect of the present invention, there is provided a one-dimensional light deflection member or a one-dimensional light deflection member having a shape extending in one direction on the emission surface side of the optical member or on the surface side opposite to the emission surface side. 2. A two-dimensional light deflecting member having a shape substantially orthogonal to the shape, wherein the deflecting direction of the deflecting member is inclined by approximately 45 degrees with respect to the longitudinal direction of the first cylindrical lens. 1 or the light source apparatus according to claim 2.

According to a fourth aspect of the present invention, in the light source device according to any one of the first to third aspects, a reflective layer having light reflectivity is disposed on a side opposite to the light diffusing member of the light source. A light source device.

According to a fifth aspect of the present invention, in the light source device according to any one of the first to fourth aspects, at least one or more types of optical sheets are arranged on a side opposite to the light source of the light source device. It is a backlight unit.

The invention of claim 6 comprises an image display element that defines a display image according to transmission / light-shielding in pixel units, and the backlight unit according to claim 5 on the back of the image display element. This is a characteristic display device.

  According to the present invention, in the optical member in which the cylindrical lenses are arranged in two directions substantially orthogonal to each other, the region where the second cylindrical lens having a small size overlaps the lens side surface of the first cylindrical lens having a large size. By reducing the area, it is possible to prevent a reduction in the light deflection effect (lens effect) caused by the overlapping of the cylindrical lenses, and it is possible to reduce the luminance unevenness of the display screen. In addition, since the luminance unevenness can be reduced by the above-described optical member, the haze value of the light diffusing member disposed between the light source and the optical member can be suppressed. Therefore, it is possible to provide a light source device that can not only reduce luminance unevenness but also suppress a decrease in total light transmittance and reduce the thickness of the device, and a backlight unit and a display device including the light source device.

1 is a perspective view illustrating an example of a liquid crystal display device in an embodiment of the present invention. (A) The perspective view of the optical member 52. FIG. (B) Sectional drawing in the X direction of the optical member 52. FIG. (C) Sectional drawing in the Y direction of the optical member 52. FIG. The figure showing the optical effect | action of the optical member 52. FIG. The figure showing the optical effect | action of the optical member 52 in case the area ratio A is large. (A) The figure which showed the breadth of the light source when it observes from the observer side F in the arrangement | positioning which match | combined the direction where the light source 42 adjoins, and the longitudinal direction of the lens of the optical member 52 together. (B) The figure which showed the breadth of the light source when it observes from the observer side F in the arrangement | positioning which inclined the direction where the light source 42 adjoins, and the longitudinal direction of the lens of the optical member 52. FIG. The figure showing the optical effect at the time of combining the optical member 52 and the light deflection | deviation member 53. FIG. Schematic which shows the structural example of the liquid crystal display device by a prior art.

Below, the form for implementing this invention is demonstrated.
First, an example of an embodiment of the present invention is shown in FIG. FIG. 1 is a perspective view showing an example of a light source device 20, a backlight unit 21, and a display device 22 of the present invention. 1 to 7 are schematic views, and the size and shape of each part are exaggerated as appropriate for easy understanding.

The display device 22 includes an image display element 32 and a backlight unit 21. The backlight unit 21 according to the embodiment of the present invention includes the light source device 20 and at least one or more types of optical sheets 54 disposed on the opposite side of the light source 42 of the light source device 20. Furthermore, the light source device 20 according to the embodiment of the present invention has a light reflection layer 46, a plurality of light sources 42 arranged two-dimensionally, light from a light diffusion plate, and the like in the observer side direction F. A diffusing member 51, an optical member 52 according to an embodiment of the present invention, and a light deflection member 53 such as a prism sheet are arranged.

The light source 42 supplies light to the image display element 32, and is configured in a two-dimensional array. Examples of the light source used for the light source 42 include a pseudo white LED obtained by adding a yellow phosphor or a green phosphor and a red phosphor to a blue light emitting diode, and an RGB type LED. In addition, a substantially point light source using an organic EL, a semiconductor laser, or the like can be used.

The reflective layer 46 is disposed on the side opposite to the observer side F of the plurality of light sources 42, and light reflected by the plurality of optical members disposed on the observer side F of the light source 42 among the light emitted from the light source 42. Can be emitted to the observer side F by further diffuse reflection. Thus, by using the reflective layer 46, the light use efficiency can be increased. The reflection layer 46 may be any member that reflects light with high efficiency. For example, a reflection film or a reflection plate having a configuration in which silver or aluminum particles or barium sulfate particles are contained in a transparent resin is used. can do.

The light diffusing member 51 is composed of a transparent resin and a light diffusing agent (particles) dispersed in the transparent resin.

As the transparent resin used for the light diffusing member 51, for example, polycarbonate resin, acrylic resin, fluorine acrylic resin, silicone acrylic resin, epoxy acrylate resin, polystyrene resin, cycloolefin polymer, methylstyrene resin, fluorene resin, PET, polypropylene, etc. can be used.

As the light diffusing agent dispersed in the transparent resin, for example, transparent particles made of an inorganic substance or a resin can be used. As the transparent particles made of an inorganic substance, for example, particles made of an oxide such as silica, alumina and titania, or other particles such as calcium carbonate and barium sulfate can be used. Transparent particles made of resin include acrylic resin, styrene resin, acrylic styrene resin or cross-linked products thereof, melamine formaldehyde resin, polytetrafluoroethylene, perfluoroalkoxy resin, tetrafluoroethylene-hexafluoropropylene copolymer, and polyfluorovinylidene. And particles made of a fluororesin such as an ethylene-tetrafluoroethylene copolymer or a silicone resin can be used.

Here, the difference in refractive index between the transparent resin in the light diffusing member 51 and the light diffusing agent dispersed in the transparent resin needs to be different in order to obtain sufficient light diffusing characteristics. This refractive index difference is desirably 0.02 or more. Moreover, the said light-diffusion agent may be used only by 1 type, and may mix and use 2 or more types.

As a production method, a light diffusing agent is dispersed in a transparent resin, and the production can be performed by a molding method such as extrusion molding or injection molding. The thickness of the light diffusing member 51 is preferably 4 mm or less in order to cope with the reduction in thickness, while it is preferably 1 mm or more in order to prevent deflection.

However, the haze value of the light diffusing member is 60% by a method according to JISK7136 in order to sufficiently bring out the luminance unevenness reducing effect of the optical member 52 and the light deflecting member 53 arranged on the observer side F of the light diffusing member 51. It is desirable that it is 95% or less. When the haze value is less than 60%, light having a strong directivity emitted from the light source 42 is emitted as it is to the observer side F, which is not good because luminance unevenness is conspicuous. On the other hand, when the haze value exceeds 95%, almost all the light emitted from the light source 42 is diffused by the light diffusing member 51, so that the optical member 52 or the light disposed on the observer side F from the light diffusing member 51. The brightness unevenness reducing effect of the deflecting member 53 is hardly exhibited. In this case, the luminance unevenness is not good because there is no significant difference compared to the case where only the light diffusion member 51 is arranged.

In addition, since the haze value is 95% or less, it is possible to prevent a reduction in light transmittance, that is, a reduction in total light transmittance.

2A is a perspective view, FIG. 2B is a cross-sectional view in the X direction, and FIG. 2C is a cross-sectional view in the Y direction. On the surface, there are a convex first cylindrical lens 61 formed at a predetermined pitch, and a convex second cylindrical lens 62 formed in a direction substantially orthogonal to the first cylindrical lens 61. The area of the region S included in the second cylindrical lens 62 on the lens side surface of the first cylindrical lens 61 is 5% or more with respect to the total surface area of the lens side surface of the first cylindrical lens 61. It is characterized by being 40% or less. Here, the predetermined pitch is assumed to be within a range of 50 μm to 600 μm. The light transmissive substrate 64 may contain a light diffusing agent.

The lenticular lens sheet in which the cylindrical lenses are arranged in one direction can raise the light from the light source 42 over a wide range by the curved surface of the lens. For this reason, when the light source 42 is observed through the lenticular lens sheet, it appears to expand greatly one-dimensionally. With a cross lenticular lens sheet in which cylindrical lenses are arranged substantially orthogonally, the light can be spread two-dimensionally. Therefore, luminance unevenness can be reduced with respect to a plurality of light sources 42 arranged two-dimensionally with a single lens sheet. Has an effect.

However, a part of the lens side surface of the first cylindrical lens 61 which is longer than the second cylindrical lens whose longitudinal direction is substantially orthogonal is included in the second cylindrical lens 62 which is approximately orthogonal, and the side region S is included. Therefore, the lens effect of the first cylindrical lens 61 is lost. When the ratio A of the area S of the included region S to the total surface area of the lens side surface of the first cylindrical lens 61 (referred to as area ratio A) exceeds 40%, the first cylindrical lens 61 The light cannot be spread sufficiently with respect to the direction of the arrangement. This is because the included region S is located in the lower part of the side surface of the lens (close to the base material 64) and has a large inclination, so that the effect of greatly expanding the light from the light source 42 is particularly great. On the contrary, when the area ratio A is less than 5%, the first cylindrical lens 61 becomes too large to be thinned, or the second cylindrical lens 62 becomes too small to sufficiently spread the light. This is not preferable because the number of regions having a small number becomes small, or the diffraction effect caused when the second cylindrical lens 62 becomes too small can be ignored. The height H2 of the top C2 of the second cylindrical lens 62 is 10 μm or more in order to obtain a sufficient tilt while ignoring the diffraction effect, and the top of the first cylindrical lens 61 in order not to increase the thickness of the member. The height H1 of C1 needs to satisfy 100 μm or less. Therefore, the area ratio A needs to be 5% or more. Here, the lens side surface of the first cylindrical lens 61 refers to the surface of the lens portion that protrudes from the base material 64 toward the exit surface side.

FIG. 3 is an optical path diagram showing an optical path of light incident on the optical member 52 in the embodiment of the present invention. When viewed from the direction (a), the light emitted from the light source 42 is directed to the front direction as shown in FIG. 3 by the second cylindrical lens 62. Appears to have spread, and it appears as if there is a substantially wide light source 42a. Further, when the optical path is viewed from the direction (b), it looks as if a substantially wide light source 42b exists due to the effect of the first cylindrical lens 61. As a result, when observed from the observer side F, the light source 42 is observed in a substantially cross-shaped manner as indicated by 42a and 42b in FIG. On the other hand, FIG. 4 shows an optical path diagram showing an optical path of incident light when the area ratio A is large. Since there are few lens side surfaces of the first cylindrical lens 61, when viewed from the direction (b), there is light that passes almost as it is without being influenced by the lens as shown by the emitted light hb 2, and is directed toward the front direction. The range of light to be produced becomes small as shown in 42b in FIG. Therefore, the luminance unevenness reducing effect is reduced.

The aspect ratios representing the ratios of the heights H1 and H2 from the base material 64 to the lens tops C1 and C2 with respect to the lens widths W1 and W2 of the first and second cylindrical lenses 61 and 62 are 0.3 or more and 1.0, respectively. The following is desirable. The larger the aspect ratio, the larger the lens surface tilt, and the more effective it is to spread a wider range of light. However, when the aspect ratio is 1.0 or more, it is not desirable because it is difficult to cut the cylindrical lens mold and the shapeability is deteriorated at the time of molding.

The cross-sectional shape of the first and second cylindrical lenses 61 and 62 is not limited to a perfect semicircular shape (spherical lens), but a semi-elliptical shape (elliptical lens), a parabolic shape (parabolic lens), and the like. Aspherical ones, and high-order aspherical ones having secondary and subsequent terms can also be used. In a perfect semicircular lens, the area of a region with a large tangential slope (for example, 1.0 or more) is small on the lens side surface, so the effect of spreading light is limited. Since the area of the region where the inclination of the tangential line is large can be sufficient, an effect of spreading light can be obtained.

The shapes of the first and second cylindrical lenses 61 and 62 may be the same or different. When the shapes of the first and second cylindrical lenses 61 and 62 are the same, the sizes of 42a in FIG. 3 and 42b in FIG. 3 are substantially equal. On the other hand, when the two cylindrical lenses have different shapes, the sizes of 42a in FIG. 3 and 42b in FIG. 3 can be changed. The aspect ratio of the cylindrical lens is reduced in the direction in which the intervals of the light sources 42 are arranged short, and the aspect ratio of the cylindrical lens is increased in the direction in which the intervals of the light sources 42 are arranged apart. By doing in this way, even when the interval between the adjacent substantially point light sources 42 is different depending on the direction, the luminance unevenness of the entire display screen can be reduced.

The optical member 52 is molded on the light transmissive substrate 64 using UV or radiation curable resin, or PET (polyethylene terephthalate), PC (polycarbonate), PMMA (polymethyl methacrylate), COP (cycloolefin polymer). Etc.) can be formed by an extrusion molding method, an injection molding method, or a hot press molding method well known in the art.

Further, as a method of reducing luminance unevenness, in the arrangement of the light source 42, a method in which the direction in which the light source 42 is closest to the longitudinal direction of the lens of the optical member 52 is inclined, and light such as a prism sheet is applied to the observer side F of the optical member 52 A method of arranging the deflecting member 53 is mentioned. However, in the latter case, the light deflection direction of the light deflection member 53 needs to be inclined approximately 45 degrees with the longitudinal direction of the first cylindrical lens 61. Here, as the light deflection member 53, a one-dimensional light deflection member such as a prism sheet extending in one direction or a convex or concave lenticular lens sheet, or a one-dimensional light deflection element extending in one direction is substantially orthogonal. And a two-dimensional light deflecting member such as a microlens shape. The prism shape may be a polygonal shape or a prism shape having a curved side surface. Of course, the same light deflection member 53 as the optical member 52 may be used. Either one of the methods may be taken, or both methods may be combined.

FIG. 5A is a diagram showing the spread of the light source when observed from the observer side F in an arrangement that does not use the former method, and FIG. 5B is an arrangement that uses the former method. is there. By this method, as shown in FIG. 5B, the light spread in a substantially cross shape by the optical member 52 can be efficiently used for reducing luminance unevenness.

In the latter case, the light deflecting member 53 having the effect of spreading the light in the direction that does not show the effect of spreading the light of the optical member 52 is arranged to have the effect of spreading the light in any direction. Will be able to. FIG. 6 shows an optical path diagram when a microlens sheet is arranged as the light deflection member 53. Due to the effect of the micro lens, as shown in FIG. 6, the light can be spread in a direction that does not show the effect of spreading the light of the optical member 52.

The light deflecting member 53 may be disposed between the light diffusing member 51 and the optical member 52.

Furthermore, at least one optical sheet 54 may be arranged on the observer side F. Examples of the optical sheet 54 include a diffusion sheet, a prism sheet, and a reflective polarization separation sheet. The optical sheet 54 has a light condensing or diffusing function, and can adjust optical characteristics such as brightness and light distribution characteristics.

As shown in FIG. 1, there is an image display element 32 on the most observer side F of the display device 22 according to the embodiment of the present invention. The image display element 32 includes two polarizing plates (polarizing films) 31 and 33 and a liquid crystal panel 35 sandwiched therebetween. The liquid crystal panel 35 is configured, for example, by filling a liquid crystal layer between two glass substrates.

The image display element 32 is preferably an element that displays an image by transmitting / blocking light in pixel units. If an image is displayed by transmitting / blocking light in pixel units, the light source device 20 can display light with high image quality by using light with reduced unevenness of the light source 42.
The image display element 32 is preferably a liquid crystal display element. A liquid crystal display element is a typical element that transmits and blocks light in pixel units and displays an image, and can improve image quality compared to other display elements.

Examples actually performed using the backlight unit and the display device as described above will be described below. In addition, this invention is not limited only to these Examples.

A pseudo white LED is used as the light source 42, and the LED is arranged at the apex portion where the squares with a distance of 25 mm are arranged so as to be a common arrangement as the current backlight, and white PET is arranged as the reflection layer 46 between them. . On the upper surface, the light diffusing member 51, the optical member 52, the light deflecting member 53, and the optical sheet 54 are arranged in this order to form the backlight unit 21 as shown in FIG. Using this backlight unit 21, the distance between the light emission surface of the LED and the bottom surface of the light diffusion plate was set to 20 mm and 18 mm, and the luminance unevenness and the luminance were evaluated. Evaluation was judged visually.
(Example)

A plurality of types of light diffusing plates having different haze values as the light diffusing member 51, a plurality of types of cross lenticular lens sheets having different area ratios A and aspect ratios as the optical member 52, the same as the optical member 52 as the light deflecting member 53, optical A diffusion sheet was prepared as the sheet 54. The haze value of the light diffusing plate was set to 10%, 50%, 60%, 90%, 95%, 99% by a method according to JISK7136. In the cross lenticular lens sheet, the area ratio A is changed to 3%, 5%, 20%, 30%, 40%, 50%, 60%, and the aspect ratio is 0.2, 0.3, 0.5 and 1.0 were prepared. Each sheet had the same first and second lens shapes. The longitudinal direction of the first cylindrical lens 61 in the light deflection member 53 is arranged so as to be inclined by 45 degrees with respect to the first cylindrical lens 61 in the optical member 52.
(Comparative example)

  As comparative examples, a light diffusing plate having a different haze value, a prism sheet having an apex angle extending in one direction of 90 degrees, a prism sheet having an apex angle extending in one direction of 90 degrees, and a diffusion sheet were prepared. The two prism sheets were arranged so as to be substantially orthogonal. The haze value of the light diffusing plate was set to 10%, 50%, 60%, 90%, 95%, 99% by a method according to JISK7136.

The results of Examples and Comparative Examples are shown in Tables 1 and 2. Regarding the luminance unevenness, the case where the luminance unevenness could not be observed was indicated as ◯, and the case where the luminance unevenness was observed as ×. Regarding the luminance, the brighter than the comparative example having a haze value of 99%, which is the current general configuration, was marked with ◯, and the brightness that was less than or equal to that of the comparative example was marked with ×.

  As a result, when the area ratio A is 5% -40%, the aspect ratio is 0.3-1.0, and the haze value of the light diffusion plate is 60% -95%, a higher luminance unevenness reduction effect is confirmed, It was confirmed that brightness reduction can also be suppressed. When the area ratio A was 3%, color unevenness was observed by diffraction.

F: observer side direction, K, h ... light, L ... viewing surface (display display surface), 20 ... light source device, 21, 44 ... backlight unit, 22, 70 ... display device, 31, 33 ... polarizing plate, 32 ... Liquid crystal panel, 35 ... Liquid crystal layer, 41, 42 ... Light source, 42a, 42b, 42c ... Apparent light source, 45, 46 ... Reflective layer, 50 ... Optical sheet, 51 ... Light diffusion member, 52 ... (Cross lenticular) In a lens-shaped optical member, 53... A light deflecting member, 54... An optical sheet, 61... First cylindrical lens, 62 ... second cylindrical lens, 64. Side surface region included in second cylindrical lens, C: lens top, W: lens width, H: height from substrate 64 to lens top.

Claims (6)

A plurality of light sources arranged two-dimensionally;
A light diffusing member for diffusing light emitted from the light source;
An optical member for controlling light emitted from the light diffusion member;
With
On the exit surface of the optical member,
A convex first cylindrical lens formed at a predetermined pitch, and a convex second cylindrical lens formed in a direction substantially orthogonal to the first cylindrical lens,
In the lens side surface of the first cylindrical lens, the area of the region enclosed in the second cylindrical lens state, and are 5% to 40% relative to the total surface area of the lens side surface,
An aspect ratio representing a ratio of the height to the lens top with respect to the lens width of the first and second cylindrical lenses is 0.3 or more and 1.0 or less, and
The light source device, wherein a haze value of the light diffusing member is 60% or more and 95% or less . The light source device according to claim 1, wherein the first and second cylindrical lenses have aspherical cross sections. A one-dimensional light deflection member having a shape extending in one direction on the emission surface side of the optical member or the surface opposite to the emission surface side or a shape in which the shape of the one-dimensional light deflection member is substantially orthogonal. has a two-dimensional optical deflector having deflection direction of the deflection member, according to claim 1 or claim 2, characterized in that inclined longitudinal direction substantially 45 degrees of the first cylindrical lens Light source device. The light source device according to any one of claims 1 to 3, the light source device, wherein a reflective layer having light reflectivity, and the light diffusing member of the light source is arranged on the opposite side. The light source device according to any one of claims 1 to 4, a backlight unit, which comprises arranging at least one or more optical sheets, the light source and the opposite side of the light source device. An image display element that defines a display image according to transmission / shading in pixel units;
The backlight unit according to claim 5 on the back surface of the image display element,
A display device comprising:

Images