JP2009294578A - Optical sheet, and back-light unit and display apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical sheet which prevents, even when a display apparatus is continuously used for a long time, the warpage and peeling thereof caused by thermal deformation, and prevents deterioration in image quality , and to provide a back-light unit and various display apparatuses. <P>SOLUTION: The back-light unit is provided with: a light source; and an optical sheet supplying light from the light source to a liquid crystal display. The optical sheet has at least a light diffusion layer and an optical layer. At least either in the space between the light diffusion layer and the optical layer or in the light diffusion layer, or in both of them, a plurality of air layers penetrating through the space between the light diffusion layer and the optical layer or through the light diffusion layer are provided. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a backlight unit that illuminates a liquid crystal panel on which a display element whose display pattern is defined according to transmission / non-transmission or transparency / scattering state in pixel units is arranged from the back side, a liquid crystal display, and a transmission The present invention relates to various display devices such as mold screens and EL displays, and further to solar cells.

In recent years, liquid crystal display devices using TFT liquid crystal panels and STN liquid crystal panels are being commercialized mainly in color notebook PCs (personal computers) in the OA field.
In such a liquid crystal display device, a so-called backlight unit method, in which a light source is disposed on the back side (observer side) of the liquid crystal panel and the liquid crystal panel is illuminated with light from the light source, has been conventionally employed. ing.

  The backlight unit employed in this type of backlight unit system is roughly classified into light source lamps such as cold cathode fluorescent lamps (CCFLs) and external electrode fluorescent lamps (EEFLs), such as acrylic resin having excellent light transmittance. There are a “light guide plate light guide method” (so-called edge light method) in which multiple reflections are made within a flat light guide plate, and a “direct type” method that does not use a light guide plate.

As a liquid crystal display device on which a light guide plate light guide type backlight unit is mounted, for example, the one shown in FIG. 31 is generally known.
This is provided with a liquid crystal panel 72 sandwiched between polarizing plates 71 and 73 at the top, and a light guide plate 79 made of a transparent base material such as a substantially rectangular plate-like PMMA (polymethyl methacrylate) or acrylic on the lower surface side. Is installed, and a diffusion film (diffusion layer) 78 is provided on the upper surface (light emission side) of the light guide plate.

  Further, a scattering reflection pattern portion for efficiently scattering and reflecting the light introduced into the light guide plate 79 in the direction of the liquid crystal panel 72 is provided on the lower surface of the light guide plate 79 by printing or the like. A reflection film (reflection layer) 77 is provided below the scattering reflection pattern portion (not shown).

Further, the light guide plate 79 is provided with a light source lamp 76 at the side end, and further covers the back side of the light source lamp 76 so that the light from the light source lamp 76 can be efficiently incident on the light guide plate 79. Thus, a high-reflectance lamp reflector 81 is provided. The scattering reflection pattern portion is formed by printing, drying, and forming a mixture of white titanium dioxide (TiO ₂ ) powder in a solution such as a transparent adhesive in a predetermined pattern, for example, a dot pattern. The light incident on the light plate 79 is imparted with directivity and guided to the light exit surface side, which is a device for increasing the brightness.

  Furthermore, recently, in order to increase the light utilization efficiency and increase the brightness, as shown in FIG. 32, a prism film (prism layer) having a light condensing function between the diffusion film 78 and the liquid crystal panel 72 is provided. ) 74 and 75 are proposed. The prism films 74 and 75 are configured to collect light emitted from the light exit surface of the light guide plate 79 and diffused by the diffusion film 78 on the effective display area of the liquid crystal panel 72 with high efficiency.

  However, in the apparatus illustrated in FIG. 31 and FIG. 32, the control of the viewing angle is left only to the diffusibility of the diffusion film 78, which is difficult to control. The characteristic that becomes darker as you go is inevitable. For this reason, when the liquid crystal screen is viewed from the side, the luminance is greatly reduced, and the light utilization efficiency is reduced.

  Furthermore, in the apparatus using the prism film illustrated in FIG. 32, two prism films are required, which not only causes a large decrease in the amount of light due to absorption of the film but also causes an increase in cost due to an increase in the number of members. It was also.

  On the other hand, in the direct type, a display device such as a large liquid crystal TV in which the light guide plate is difficult to use is used.

  As a direct liquid crystal display device, a device illustrated in FIG. 33 is generally known. In this, a liquid crystal panel 72 sandwiched between polarizing plates 71 and 73 is provided on the upper side, and is emitted from a light source 51 made of a fluorescent tube or the like on the lower surface side thereof and diffused by an optical sheet such as a diffusion film 82. The light is condensed on the effective display area of the liquid crystal panel 72 with high efficiency. In order to efficiently use the light from the light source 51 as illumination light, a reflector 52 is disposed on the back surface of the light source 51.

  However, even in the apparatus illustrated in FIG. 33, the control of the viewing angle is left only to the diffusibility of the diffusion film 82, which is difficult to control, and the center in the front direction of the display is brighter and darker toward the peripheral part. This characteristic is inevitable. For this reason, when the liquid crystal screen is viewed from the side, the luminance is greatly reduced, and the light utilization efficiency is reduced. Furthermore, in the case of using a prism film, since the number of prism films is two, not only the light amount is greatly decreased due to absorption of the film but also the cost is increased due to an increase in the number of members.

  If the distance between the light sources 51 is too wide, uneven brightness tends to occur on the screen, and the number of light sources 51 cannot be reduced, leading to an increase in power consumption and an increase in cost.

By the way, in such a liquid crystal display device 5, light weight, low power consumption, high luminance, and thinning are strongly demanded as market needs, and accordingly, a backlight unit mounted on the liquid crystal display device is also provided. Light weight, low power consumption, and high brightness are required.
In particular, in a color liquid crystal display device that has recently made remarkable progress, the panel transmittance of the liquid crystal panel is remarkably lower than that of a monochrome-compatible liquid crystal panel. It is essential to obtain power consumption.

  However, as described above, it is difficult to say that the conventional apparatus sufficiently satisfies the demand for high luminance and low power consumption, and the user has low price, high luminance, high display quality, and low power consumption. The development of a backlight unit capable of realizing a power liquid crystal display device is awaited.

  In view of the above situation, for example, as disclosed in Patent Document 1, the present applicant includes a liquid crystal panel and light source means for illuminating light from the back side of the liquid crystal panel, and the light source means includes light from the light source. A liquid crystal display device has been proposed in which a lens layer for guiding the liquid crystal panel to the liquid crystal panel is provided and a light-shielding portion having an opening in the vicinity of the focal plane of the lens layer.

  The above-mentioned Patent Document 1 discloses a configuration in which a lens sheet having a light-shielding portion is disposed between a liquid crystal panel and a backlight unit, as shown in FIGS. 31 to 33, the lens sheet has a concavo-convex shape constituting a lens portion on the liquid crystal panel side.

The effect obtained by interposing the lens sheet described above has a concavo-convex shape that forms a lens portion on the liquid crystal panel side by modulating the diffusivity of light emitted from the light guide plate by the lens action.
The effect obtained by interposing the lens sheet described above is that the diffusibility of the light emitted from the light guide plate is modulated into the lens action, and the liquid crystal panel can be emitted with the direction aligned. .

  In addition, by forming a light-shielding portion having an opening at a specific location, it is possible to selectively increase the amount of light incident on the pixels of the liquid crystal panel, improving the use efficiency of the backlight, By controlling the shape, it is possible to control the visual field region of the display light.

JP 2000-284268 A JP 2006-106197 A

By the way, a liquid crystal display device used for a liquid crystal TV or a personal computer monitor is used continuously for a long time as compared with a mobile phone or a mobile terminal. In addition, recently, liquid crystal display devices used in mobile phones and mobile terminals are expected to be used continuously for a longer time than before due to the adoption of power saving design. Furthermore, the liquid crystal display device itself has become thinner, and the distance between the light source and the optical sheet has become shorter.
As described above, when the liquid crystal display device is used continuously for a longer period of time, the temperature of the optical sheet used in the backlight unit and various display devices rises due to the heat generated from the light source, and thermal deformation occurs. Therefore, there is a problem that image quality displayed from the liquid crystal display device may be deteriorated due to warping or peeling.

  The present invention has been made in view of such circumstances, and even when the display device is used continuously for a long time, it prevents warpage or peeling due to thermal deformation of the optical sheet, thereby lowering the image quality. It is an object of the present invention to provide an optical sheet, a backlight unit, and various display devices that can prevent the above.

The invention of claim 1
A light source;
In a backlight unit comprising an optical sheet that supplies light from the light source to a liquid crystal display device,
The optical sheet has at least a light diffusion layer and an optical layer,
A plurality of air layers between the light diffusion layer and the optical layer or between the light diffusion layer and the optical layer, or at least one of the light diffusion layers, or both. It is an optical sheet characterized by having.
The invention of claim 2
A light source;
In a backlight unit comprising an optical sheet that supplies light from the light source to a liquid crystal display device,
The optical sheet is
Consisting of a diffusing member and an optical layer,
The optical layer is
A photomask arranged in a plurality of stripes on the non-incident surface of the diffusing member;
A light transmission portion disposed between two adjacent optical masks;
On the light mask and the light transmission part, a lens part in which a plurality of unit convex cylindrical lenses are arranged in parallel on the display side,
A surface opposite to the lens portion, and a non-lens surface on which light transmitted by the light transmission portion is incident,
The plurality of unit convex cylindrical lenses correspond to each of the light transmitting portions on a 1: 1 basis, and a perpendicular line from the apex of the corresponding unit convex cylindrical lens to the non-lens surface of the cylindrical lens is the light transmitting portion. Part
And a lenticular sheet arranged in a stripe shape along the longitudinal direction of each unit of the optical mask,
The diffusion member is
A plurality of light deflection elements are provided on the surface of the diffusing member opposite to the observer, and a striped air layer is formed in the diffusing member,
The longitudinal direction is a horizontal direction;
Both ends in the longitudinal direction of each light transmission part and both ends of each air layer are open in the horizontal direction,
And the pressure loss ΔP of the air flowing in the light transmitting part and the air layer is 0 (Pa) <ΔP <2.2 × 10 ² (Pa)
And
The optical sheet is characterized in that a horizontal dimension is larger than a vertical dimension.
The invention of claim 3
A light source;
In a backlight unit comprising an optical sheet for supplying light from the light source to a liquid crystal display device,
The optical sheet is
Consisting of a diffusing member and an optical layer,
The optical layer is
A plurality of fixing elements disposed on the non-incident surface of the diffusing member;
The light transmission part disposed between the adjacent fixing elements;
On the fixed element and the light transmission part, a lens part in which a plurality of the unit convex cylindrical lenses are arranged in parallel in a stripe shape on the display side;
A surface opposite to the lens unit, and a non-lens surface on which light transmitted by the light transmission unit is incident,
The diffusion member is
A plurality of light deflection elements are provided on the surface of the diffusing member opposite to the observer, and a striped air layer is formed in the diffusing member,
Both ends of each light transmission part and both ends of each air layer are open in the horizontal direction,
And the pressure loss ΔP of the air flowing in the light transmitting part and the air layer is 0 (Pa) <ΔP <2.2 × 10 ² (Pa)
And
The optical sheet is characterized in that a horizontal dimension is larger than a vertical dimension.
The invention of claim 4
A light source;
In a backlight unit comprising an optical sheet for supplying light from the light source to a liquid crystal display device,
The optical sheet is
Consisting of a diffusing member and an optical layer,
The optical layer is
A plurality of fixing elements disposed on the non-incident surface of the diffusing member;
The light transmission part disposed between the adjacent fixing elements;
On the fixed element and the light transmission part, a lens part in which a plurality of the unit convex cylindrical lenses are arranged in parallel in a stripe shape on the display side;
A surface opposite to the lens unit, and a non-lens surface on which light transmitted by the light transmission unit is incident,
The diffusion member is
A plurality of light deflection elements are provided on the surface of the diffusing member opposite to the observer, and a striped air layer is formed in the diffusing member,
Both ends of each light transmission part and both ends of each air layer are open in the vertical direction,
And the pressure loss ΔP of the air flowing in the light transmitting part and the air layer is 0 (Pa) <ΔP <2.2 × 10 ² (Pa)
And
The optical sheet is characterized in that a horizontal dimension is larger than a vertical dimension.
The invention of claim 5
A light source;
In a backlight unit comprising an optical sheet that supplies light from the light source to a liquid crystal display device,
The optical sheet is
Consisting of a diffusing member and an optical layer,
The optical layer is
A photomask arranged in a plurality of stripes on the non-incident surface of the diffusing member;
A light transmission portion disposed between two adjacent optical masks;
On the light mask and the light transmission part, a lens part in which a plurality of unit convex cylindrical lenses are arranged in parallel on the display side,
A surface opposite to the lens portion, and a non-lens surface on which light transmitted by the light transmission portion is incident,
The plurality of unit convex cylindrical lenses correspond to each of the light transmitting portions on a 1: 1 basis, and a perpendicular line from the apex of the corresponding unit convex cylindrical lens to the non-lens surface of the cylindrical lens is the light transmitting portion. Part
And a lenticular sheet arranged in a stripe shape along the longitudinal direction of each unit of the optical mask,
The diffusion member is
A striped air layer is formed in the diffusion member having a plurality of light deflection elements on the surface of the diffusion member opposite to the observer,
The longitudinal direction is a horizontal direction;
Both ends in the longitudinal direction of each light transmission part and both ends of each air layer are open in the horizontal direction,
The diffusion member is
A plurality of light deflection elements are provided on the surface of the diffusing member opposite to the observer, and a striped air layer is formed in the diffusing member,
Both ends of each light transmission part and both ends of each air layer are open in the horizontal direction,
And the pressure loss ΔP of the air flowing in the light transmission part, the air layer, and the diffusion member is 0 (Pa) <ΔP <4.4 × 10 ² (Pa).
And
The optical sheet is characterized in that a horizontal dimension is larger than a vertical dimension.
The invention of claim 6
6. A display device comprising the backlight unit according to claim 1 and an image display unit thereon.
The invention of claim 7
A light source;
A cooling method for a backlight unit comprising an optical sheet for supplying light from the light source to a liquid crystal display device,
The optical sheet is
Consisting of a diffusing member and an optical layer,
The optical layer is
A photomask arranged in a plurality of stripes on the non-incident surface of the diffusing member;
A light transmission portion disposed between two adjacent optical masks;
On the light mask and the light transmission part, a lens part in which a plurality of unit convex cylindrical lenses are arranged in parallel on the display side,
A surface opposite to the lens portion, and a non-lens surface on which light transmitted by the light transmission portion is incident,
The plurality of unit convex cylindrical lenses correspond to each of the light transmitting portions on a 1: 1 basis, and a perpendicular line from the apex of the corresponding unit convex cylindrical lens to the non-lens surface of the cylindrical lens is the light transmitting portion. Part
And a lenticular sheet arranged in a stripe shape along the longitudinal direction of each unit of the optical mask,
The diffusion member is
A plurality of light deflection elements are provided on the surface of the diffusing member opposite to the observer, and a striped air layer is formed in the diffusing member,
The longitudinal direction is a horizontal direction;
The both ends of the light transmitting portions in the longitudinal direction and both ends of the air layers are opened in the horizontal direction so that air enters and exits the light transmitting portions and the air layers, and the optical sheet When the backlight is heated by the light emitted from the light source, the pressure loss ΔP is 0 (Pa) <ΔP <2.2 × 10 ² (Pa). In this cooling method, the backlight unit is cooled by the air flowing in the light transmitting portion and the air layer in the horizontal direction.
The invention of claim 8
A light source;
A cooling method for a backlight unit comprising an optical sheet for supplying light from the light source to a liquid crystal display device,
The optical sheet is
Consisting of a diffusing member and an optical layer,
The optical layer is
A plurality of fixing elements disposed on the non-incident surface of the diffusing member;
The light transmission part disposed between the adjacent fixing elements;
On the fixed element and the light transmission part, a lens part in which a plurality of the unit convex cylindrical lenses are arranged in parallel in a stripe shape on the display side;
A surface opposite to the lens unit, and a non-lens surface on which light transmitted by the light transmission unit is incident,
The diffusion member is
A plurality of light deflection elements are provided on the surface of the diffusing member opposite to the observer, and a striped air layer is formed in the diffusing member,
By opening both ends of each light transmitting portion and both ends of each air layer in the horizontal direction, air enters and leaves the light transmitting portion and the air layer, and the dimensions of the optical sheet are When the horizontal direction is made larger than the vertical direction and the backlight generates heat due to light emitted from the light source, the air has a pressure loss ΔP of 0 (Pa) <ΔP <2.2 × 10 ² (Pa). In this cooling method, the backlight unit is cooled by flowing in the light transmitting portion and the air layer in the horizontal direction.
The invention of claim 9
A light source;
A cooling method for a backlight unit comprising an optical sheet for supplying light from the light source to a liquid crystal display device,
The optical sheet is
Consisting of a diffusing member and an optical layer,
The optical layer is
A plurality of fixing elements disposed on the non-incident surface of the diffusing member;
The light transmission part disposed between the adjacent fixing elements;
On the fixed element and the light transmission part, a lens part in which a plurality of the unit convex cylindrical lenses are arranged in parallel in a stripe shape on the display side;
A surface opposite to the lens unit, and a non-lens surface on which light transmitted by the light transmission unit is incident,
The diffusing member has a plurality of light deflection elements on the surface of the diffusing member opposite to the observer, and a striped air layer is formed in the diffusing member,
By opening both ends of each light transmitting portion and both ends of each air layer in the vertical direction, air enters and leaves the light transmitting portion and the air layer, and the dimensions of the optical sheet are When the horizontal direction is made larger than the vertical direction and the backlight generates heat due to light emitted from the light source, the air has a pressure loss ΔP of 0 (Pa) <ΔP <2.2 × 10 ² (Pa). In the cooling method, the backlight unit is cooled by flowing from the lower direction to the upper direction in the light transmission part and the air layer.

Optical sheet, backlight unit, and various displays that can prevent warpage and peeling due to thermal deformation of the optical sheet and prevent deterioration in image quality even when the display device is used continuously for a long time An apparatus can be provided.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown to Fig.1 (a), the display apparatus 5 concerning embodiment of this invention is comprised by providing the display part 21 on the backlight unit 13 which irradiates light to the viewer side X, and is provided. The display device 5 displays a planar image by emitting display light whose display is controlled by an image signal from the display unit 21 toward the viewer side X. In the following, the upper direction in FIG. 1A is referred to as the viewer side X, and the lower direction is referred to as the back side. Further, in FIG. 1A, the display device 55 is the liquid crystal display device 5 because the display unit 21 includes the liquid crystal layer 15.

  If the display device 5 includes at least the backlight unit 13, the light from the backlight unit 13 is displayed as display light, such as a liquid crystal display device, a rear projection screen device, a plasma display, and an EL display. As long as the display device 5 performs image display, the type thereof is not limited.

  As shown in FIGS. 2 to 4, the display device 5 according to the embodiment of the present invention includes a diffusion film 7, a prism sheet 8, a polarization separation / reflection sheet 9, and the like on the viewer side X or the back side of the optical sheet 11. You may install in. With the above-described configuration, the image quality can be further improved.

  Here, the diffusion film 7 is for refracting, condensing and diffusing incident light. For example, by installing the diffusion film 7 on the viewer side X of the optical sheet 11, the light from the light source 1 can be further diffused, and the brightness of the image of the display device 5 is displayed more uniformly. It becomes possible.

Further, by providing the diffusion film 7 between the members having a plurality of periodic patterns due to the above-described diffusion effect, it is possible to prevent the occurrence of so-called moiré due to the members having the plurality of periodic patterns. Become. Examples of the member having a plurality of periodic patterns include a pixel pattern of the display unit 21, a lens sheet arranged in a stripe shape or a lattice shape, and a prism sheet.
In this case, the diffusion film 7 is formed by applying a filler on one surface of the transparent substrate and exposing a part of the filler on the surface, or by UV molding, extrusion, hot pressing, or injection molding. .

  Further, as the above-mentioned diffusion film 7, it is also possible to use a two-dimensional array of substantially hemispherical microlenses having a diameter of 100 μm or less formed on one surface of a smooth transparent substrate by UV molding, extrusion, and soft molding. Good. In this case, since the incident light has an effect of condensing / diffusing in particular, the light of the light source 1 can be collected in the front direction (viewer side X direction), and the brightness of the display light of the display device 5 can be further increased. Can be brightened.

By using the diffusion film 7 as described above, the image quality of the display device 5 can be further improved. However, when the diffusion film 7 is not disposed and the image quality such as brightness, uniformity of brightness, and moire is sufficient, it is needless to say that the diffusion film need not be installed.
When the diffusion film 7 is not installed, the number of parts can be reduced, and the cost can be reduced and the display device 5 can be made thinner and lighter.

  Next, since the prism sheet 8 has a function of condensing light from the light source 1 in the viewer side X direction, the brightness of the display device 55 can be further increased. However, the prism sheet 8 may not be provided when the brightness is sufficient without the prism sheet 8 being disposed.

Furthermore, the polarization separating / reflecting sheet 9 transmits only a specific linearly polarized light component and reflects light other than the specific linearly polarized light component.
Here, when a liquid crystal panel is used for the display unit 21, the polarizing plate 17 is disposed on the liquid crystal panel. The polarizing plate 17 transmits light of a specific linearly polarized component, and light other than the specific linearly polarized component is transmitted. Absorbed and light utilization efficiency decreases. When the polarization separation reflection sheet 9 is arranged, the light from the light source 1 is transmitted in the front direction (viewer side X direction) only for the specific linear polarization component that matches the polarizing plate 17 described above, and other than the specific linear polarization component The light is reflected to the back side without being absorbed. The transmitted light having the specific linearly polarized light component is transmitted by the polarizing plate 17 without light absorption. Thus, since light absorption does not occur, light utilization efficiency can be improved. However, when the polarization separation / reflection sheet 9 is not disposed and the brightness of the display light of the display device 5 is sufficient, the polarization separation / reflection sheet 9 may not be provided.

  The backlight unit 13 of the present embodiment includes a light source 1 arranged in parallel, a reflecting plate 3 that reflects light from the light source 1, and optical that diffuses and irradiates direct light from the light source 1 and reflected light from the reflecting plate 3. A sheet 11 is provided.

  The light source 1 supplies light (display light) used for image display of the display device 5.

As the light source 1 used in the present invention, a linear light source 1a may be used. FIG.1 (b) shows sectional drawing of the linear light source 1a.
Examples of the linear light source 1a include ordinary fluorescent tubes, cold cathode tubes, hot cathode tubes, external electrode tubes, LEDs and semiconductor lasers arranged in a row, in particular, cold cathode tubes, external electrode tubes. Or it is preferable to set it as LED arranged in a line.

  The linear light source 1a is composed of, for example, a transparent columnar light guide formed in a columnar shape or a prism shape extending in one direction, and LEDs arranged above and below the columnar light guide along the thickness direction. May be. When the linear light source 1a is configured in this way, when the LED light is incident from above and below the columnar light guide, the LED light can be emitted to the side of the columnar light guide.

  In the present invention, the distance between the centers of the adjacent linear light sources 1a is preferably 15 mm to 150 mm, and more preferably 20 mm to 100 mm. When the distance between the centers of the adjacent linear light sources 1a is less than 15 mm, the number of the linear light sources 1a necessary for arranging the light sources 1 on the display device 5 without a gap increases, and the power consumption increases. Further, when the distance between the centers of the adjacent linear light sources 1a exceeds 150 mm, the distance between the linear light sources 1a is increased, resulting in darkness between the linear light sources 1a and uneven brightness.

  The linear light source 1a and the diffusing member 25 are installed so that the dimension of the shortest distance between the incident surface of the diffusing member 25 and the center position of the linear light source 1a is 1 mm to 30 mm or less. More preferably, the dimension of the shortest distance between the incident surface of the diffusing member 25 and the center position of the linear light source 1a is 3 mm to 25 mm. In the case where the dimension of the shortest distance between the center position of the linear light source 1a and the incident surface of the optical sheet 11 is less than 1 mm, there is a space necessary for sufficient light diffusion between the light source 1 and the optical sheet 11. Since it cannot be ensured, uneven brightness occurs. In addition, when the dimension of the shortest distance between the center position of the point light source 1b and the incident surface of the optical sheet 11 exceeds 30 mm, the thickness of the backlight unit 13 increases, and the backlight unit 13 becomes thicker and heavier. Problems arise.

  When the light source 1 is the linear light source 1a, the number of the linear light sources 1a is not specifically limited. For example, when the direct type backlight device of the present invention is used for a 32-inch liquid crystal display device 5, the number of linear light sources 1a is, for example, an even number such as 16, 14, 12, 8, or the like. , Can be an odd number.

Further, as the light source 1 used in the present invention, a point light source 1b may be used as shown in FIG. FIG. 5B shows an example of the arrangement of the point light sources 1b. In the case of using the point light source 1b, a light emitting diode (hereinafter referred to as LED) having good light emission efficiency is preferable. By providing the point light source 1b, it is possible to use a so-called local dimming method in which the brightness changes with time for each display position. By using the local dimming method, it is possible to increase the contrast ratio on the same screen by turning on the point light source 1b at the bright image display position and turning off the point light source 1b at the dark image display position. Thus, the image quality is improved.
FIG. 6A illustrates a blue LED element 50 that emits blue light, which is used in a mobile device such as a mobile phone, and is covered with a phosphor 51 that emits yellow light that is applied to the inside of the LED lens 53, and becomes pseudo white. The white LED 46 emits light.
This method has an advantage that pseudo white light emission can be realized simply by covering the phosphor with a single-color LED element. In addition, the light source 1 used in the present invention is not limited to the above-described one, and may be one in which one single-color LED element is covered with at least one kind of phosphor.

  Next, FIG.6 (b) adds the prism shape to the lens 53 for LED of Fig.6 (a). By using the prism, the light distribution of the light emitted from the white LED 46 can be adjusted.

  FIG. 7 shows a method of emitting pseudo white light by combining LED devices (red LED element 48, green LED element 49, blue LED element 50) that emit light in a single color as another method of LEDs emitting pseudo white light. In this case, as compared with the case of FIG. 6 as described above, the problem that the phosphor 51 deteriorates due to heat generated from the LED elements can be avoided, and an arbitrary color can be obtained by adjusting the amount of light of each LED element. Can do.

FIG. 8 shows a point light source unit 52 configured by combining single color LEDs (red LED 54, green LED 55, blue LED 56) that emit light in a single color. In this case, the red LED 54, the green LED 55, and the blue LED 56 may be combined one by one as shown in FIG. 8B to constitute the point light source unit 52, or the light output is weak as shown in FIG. 8C. A plurality of (for example, green LEDs 55) may be arranged to constitute the point light source unit 52.
By forming the above-described point light source unit 52, it is also possible to adopt a configuration in which color display is performed using a field sequential method in which each color LED is colored in a time-sharing manner.

  When forming the point light source unit 52 described above, the number of LEDs is not limited. Moreover, when arrange | positioning the above-mentioned point light source unit 52, it is preferable that the color which the adjacent LED light-emits differs between adjacent point light source units 52. The reason for this is that when the colors emitted by the adjacent LEDs are the same, the intensity of the colors emitted by the adjacent LEDs is increased and is viewed as color unevenness from the viewer side X.

  The point light source 1b is not limited to the above-described LED. For example, as shown in FIG. 9, the light of a monochromatic semiconductor laser (red semiconductor laser 57, green semiconductor laser 58, blue semiconductor laser 59) is mixed through a fiber 60 and emitted from a semiconductor laser lens 61. Also good. In addition, a normal fluorescent lamp or a halogen lamp may be used.

  You may comprise the point light source unit 52 combining the above-mentioned each point light source 1b. For example, the point light source unit 52 may be configured by combining a white LED and a red LED that is a single color LED. In the above-described configuration, red light can be complemented to white light of the white LED by emitting red light of the red LED. Therefore, the color reproducibility can be improved.

Next, an arrangement mode of the plurality of point light sources 1b will be described.
FIG. 10 is a plan view schematically showing the arrangement of the plurality of point light sources 1b. As shown to Fig.10 (a), as a 1st aspect which arrange | positions the several point light source 1b, it shall be set as the structure arrange | positioned at predetermined intervals along the vertical direction and horizontal direction of a direct type | mold backlight apparatus. Can do. As shown in FIG. 10B, the second mode is a configuration in which P1 to P4 of the point light source 1b in FIG. 10A are removed, that is, a point light source at each of the four vertices of the square. 1b can be arrange | positioned, and also it can be set as the structure which has arrange | positioned the point light source 1b in the intersection of this rectangular diagonal. Furthermore, as shown in FIG. 10 (c), the third mode may be configured such that the point light sources 1b are respectively arranged at the apexes of the honeycomb structure in which regular hexagons are continuously formed. Alternatively, as shown in FIG. 10D, a configuration in which the point light sources 1b are linearly arranged can be employed.

  In the configuration as described above, the distance between the point light sources 1b may be uniform at all locations or may be partially changed. The case where it changes partially is, for example, the case where the distance between the point light sources 1b is narrowed at the center of the direct type backlight device.

In the present invention, the distance between the centers of the adjacent point light sources 1b is preferably 10 mm to 150 mm, and more preferably 20 mm to 100 mm. When the distance between the centers of the adjacent point light sources 1b is less than 15 mm, the number of point light sources 1b required for arranging the light sources 1 on the display device 5 without a gap increases, and the power consumption increases. Further, when the distance between the centers of the adjacent point light sources 1b exceeds 150 mm, the distance between the point light source units 52 is increased, so that the point light sources 1b become dark and uneven brightness occurs.
By setting the above distance to the above range, the power consumption of the direct type backlight device can be reduced, the assembly of the device can be facilitated, and the luminance unevenness of the light emitting surface can be suppressed.

The dimension of the shortest distance between the center position of the point light source 1b and the incident surface of the optical sheet 11 may be designed in consideration of the thickness of the direct type backlight device and the uniformity of luminance, but it is 1 mm to 30 mm. Preferably, it is 3 mm-25 mm. When the dimension of the shortest distance between the center position of the point light source 1b and the incident surface of the optical sheet 11 is less than 1 mm, a space necessary for sufficient diffusion between the light source 1 and the optical sheet 11 cannot be secured. Uneven brightness occurs. Further, when the dimension of the shortest distance between the center position of the point light source 1b and the incident surface of the optical sheet 11 exceeds 30 mm, the thickness of the backlight unit 13 increases, and the backlight unit 13 becomes thicker and heavier. Problems arise.
The point light source 1b may be replaced with the point light source unit 52 by the above-described method of arranging the point light source 1b.

Part of the light emitted from the light source 1 is incident on and reflected by the reflector 3 installed on the back side of the light source 1.
The reflection plate 3 may be formed of any material as long as it can reflect the light from the light source 1, for example, by kneading and stretching a filler or air in PET, PP (polypropylene), or the like. Resin sheet with increased reflectivity by forming voids, a sheet with a mirror surface formed by vapor deposition of aluminum on the surface of a transparent or white resin sheet, a resin sheet carrying a metal foil or metal foil such as aluminum, or sufficient on the surface It can be formed of a thin metal plate having reflectivity.

  Part of the light emitted from the light source 1 and the light reflected by the reflecting plate 3 are incident on the incident surface of the light deflection element of the optical sheet 11.

  Here, examples of the light deflection element include a light deflection lens 28 and a light deflection layer having light diffusion.

The light deflection lens 28 is composed of a unit lens having periodicity, and the unit lens is arranged in such a direction that the convex portion of the lens faces the back side.
Thereby, the light L from the light source 1 is refracted and deflected by the unit lens, and the light from the light source 1 is diffused in the light propagation layer 27.

Next, FIG. 11 to FIG. 12 are schematic cross-sectional views for explaining the light path by the light deflection lens 28.

  When light L parallel to the viewer side X direction is incident on the light deflection lens 28 from the back side, the light M incident on both ends of the unit light deflection lens 28 is deflected in the opposite direction, and the light propagation lens 27 At a crossing point and enter the diffusion base material 26. When the pitch of the unit light deflection lens 28 is P, and the width of the region (light deflection region) when the light M incident on both ends of the unit light deflection lens 28 enters the diffusion substrate 26 is S> P By satisfy | filling, since it overlaps with the light deflection area | region of the unit light deflection lens 28 which adjoins, sufficient diffusion effect can be acquired in the light propagation layer 27. FIG.

  When light L parallel to the viewer side X direction is incident on the light deflection lens 28 from the back side, the light M incident on both ends of the unit light deflection lens 28 does not intersect with each other in the light propagation layer 27. In this case, when the height of the light deflection lens 28 is L and the thickness of the light propagation layer 27 is T, the light deflection layer overlaps with the light deflection region of the adjacent light deflection lens 28 by satisfying T> 3L. 27, a sufficient diffusion effect can be obtained.

Here, the shape of the light deflection lens 28 is preferably a triangular prism shape as shown in FIG. This is because the lens can be easily molded and the incident light L from the front can be largely deflected.
Further, a convex curved lens shape as shown in FIG. Since the tangent line at each point of the first apex portion 28a and the first inclined surface 28b continuously changes, it is possible to deflect the incident light L from the front surface to various angles.
The convex curved lens shape is more preferably an aspherical shape as shown in FIG. This is because the radius of curvature of the first apex portion 28a can be reduced, so that the diffusion performance is increased.
Furthermore, the light deflection element 28 is preferably a curved triangular prism as shown in FIG. Since the first apex portion 28a is a ridge line, the incident light L can always be largely deflected regardless of the position of the lens. Moreover, since the tangent line at each point of the first inclined surface 28b continuously changes, the incident light L from the front surface can be diffused to various angles. At this time, as shown in FIG. 13 (d), the angle formed between the tangent line at each point of the first inclined surface 28b and the surface 27a opposite to the viewer side X of the light propagation layer 27 is 20 degrees to 90 degrees. It is further desirable that it varies continuously between degrees. If there is a surface below 20 degrees, the deflection angle becomes very small, and the diffusion performance becomes weak. In particular, when there is a surface at 0 degree, the incident light L is allowed to pass without being deflected at all. The curved triangular prism has no surface where the angle formed by the tangent line at each point of the first inclined surface 28b with the surface 27a opposite to the viewer side X of the light propagation layer 27 is smaller than 20 degrees. It can be deflected at a large angle regardless of where the light enters the surface 28b.
In addition, when the angle between the tangent line at each point of the first inclined surface 28b and the surface 27a on the opposite side of the light propagation layer 27 from the viewer side X does not change significantly, light is emitted to any point on the first inclined surface 28b. Even if it is incident, since the deflection angles are almost the same, the light is concentrated in the same region. In the curved triangular prism, the angle between the tangent line at each point of the first inclined surface 28b and the surface 23b on the side opposite to the observer side F of the light propagation layer 23 changes greatly in the range of 20 degrees to 90 degrees. Therefore, the incident light L can be deflected at various angles to make the light uniform.
Further, the light deflection element 28 can be used by combining a plurality of the lens shapes. For example, as shown in FIG. 13 (e), a shape in which a triangular prism is combined on a convex curved lens may be used. Alternatively, a shape in which two curved triangular prisms are shifted in the Ve direction and overlapped as shown in FIG. This is because the diffusion performance is further increased by the diffusion effect of two or more lens shapes.

  Further, it is preferably a convex curved surface shape or a triangular prism shape, a triangular prism shape having a rounded apex, or a spherical prism shape. With this shape, the light deflection can be improved and the lamp image can be reduced. For example, a lens array formed in a one-dimensional or two-dimensional arrangement can be used, and examples thereof include a prism lens array, a microlens array, a cylindrical lens array, or a lens array formed by combining these.

  The shape of the light deflection lens 28 may be a structure in which a plurality of prisms having a polygonal pyramid structure are arranged in a lattice pattern. For example, a plurality of prisms having a regular quadrangular pyramid shape may be arranged in a lattice shape. Alternatively, a plurality of prisms having a regular triangular pyramid shape may be arranged in a lattice pattern.

  The shape of the light deflection lens 28 includes first and second lens arrays provided on the incident surface of the light propagation layer 27, and the first lens array extends along one direction on the one surface and The second lens array includes a plurality of first lenses arranged in parallel, the second lens array extending along a direction perpendicular to the first lens array direction on the one surface, and a plurality of first lenses arranged in parallel to each other. Two lenses may be provided, and the second lens may include a plurality of sub-lenses disposed in the valley portions 13 of the plurality of first lenses. The lens array and sub-lens described above may be a prism array or a sub-prism.

  The shape of the light deflection lens 28 is preferably such that the cross-sectional shape orthogonal to the incident surface of the light propagation layer 27 is substantially symmetric. When the shape is substantially symmetric, the distribution of the emitted light from the light propagation layer 27 is also substantially symmetric. In this case, the brightness in the viewing direction of the specific direction does not change, and a preferable image is obtained.

  Further, the shape of the light deflection lens 28 may be a shape in which the cross-sectional shape orthogonal to the incident surface of the light propagation layer 27 is asymmetric. In the case of an asymmetric shape, the distribution of light emitted from the light propagation layer 27 is also asymmetric. Depending on the installation location of the display device 5, there are cases in which viewing is not performed from above or below the screen. In that case, it is possible to darken the non-viewing direction and make the viewing direction brighter, and it is possible to obtain a desired light distribution by making the shape of the light deflection lens 28 asymmetrical. It becomes. As an example of the asymmetrical shape, there is an asymmetrical prism in which one of the cross-sectional shapes is a curved shape, the other is formed in a linear shape, and the curved shape and the linear shape are connected with a round shape.

By performing such light deflection, the lamp image can be reduced, and the emitted light can be obtained with reduced viewing angle dependency of the light intensity. Note that the reduction of the lamp image is to scatter the light from the light source 1 to eliminate unevenness in brightness and to prevent the light source 1 from being seen through.
Even if the position of the light source 1 and the position of the light deflection lens 28 are not aligned, the light deflection lens 28 overlaps the light deflection regions of the adjacent light deflection lenses 28, so that a sufficient diffusion effect is achieved in the light propagation layer 27. Can be obtained. For this reason, it is not necessary to align the position of the light source 1 and the position of the light deflection lens 28, so that the manufacturing efficiency can be improved and the manufacturing cost can be reduced.

  The length of the pitch P of the light deflection lens 28 is preferably 0.5 mm or less, and more preferably 0.2 mm or less.

In the present invention, the light deflection element may be a light deflection layer instead of the light deflection lens 28 described above.
The light deflection layer is a layer having a light diffusing element, and has an effect of diffusing and deflecting light from the light source 1 and diffusing light from the light source 1 in the light propagation layer 27.

The light deflection layer preferably has a total light transmittance of 30% to 80%. When the total light transmittance is less than 30%, the luminance of the light emitted to the viewer side X is lowered, which is not preferable. Moreover, when the total light transmittance is larger than 80%, a sufficient light deflection effect cannot be obtained, which is not preferable. The total light transmittance is a measured value based on JIS K7361-1.
The light deflection layer preferably has a haze value of 50% or more. When the haze value is less than 50%, a sufficient light deflection effect cannot be obtained with the light deflection layer, which is not preferable. The haze value is a measured value based on JIS K7136.
The thickness of the light deflection layer is preferably equal to or less than the thickness of the light propagation layer 27. When the thickness of the light deflection layer is larger than the thickness of the light propagation layer 27, the distance through which the light is transmitted in the light propagation layer 27 is shortened. Since it enters, it is not preferable.

The light deflection layer is formed by dispersing light deflection regions in a transparent resin.
As the transparent resin, a thermoplastic resin, a thermosetting resin, or the like can be used. For example, a polycarbonate resin, an acrylic resin, a fluorine acrylic resin, a silicone acrylic resin, an epoxy acrylate resin, a polystyrene resin, or a cycloolefin polymer. , Methylstyrene resin, fluorene resin, polyethylene terephthalate (PET), polypropylene, acrylonitrile polyol copolymer, and the like can be used.

The light deflection region is preferably made of light diffusing particles. This is because a suitable light deflection performance can be easily obtained.
As the light diffusing particles, transparent particles made of an inorganic oxide or a resin can be used. As the transparent particles made of an inorganic oxide, for example, silica, alumina or the like can be used. The transparent particles made of resin include acrylic particles, styrene particles, styrene acrylic particles and crosslinked melamine-formalin condensate particles PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxy resin), FEP (tetrafluoroethylene). —Fluoropolymer particles such as hexafluoropropylene copolymer), PVDF (polyfluorovinylidene), and ETFE (ethylene-tetrafluoroethylene copolymer), silicone resin particles, and the like can be used.
Moreover, you may use combining 2 or more types of transparent particles from the transparent particle described previously. Furthermore, the size and shape of the transparent particles are not particularly defined.

In the case where a thermoplastic resin is used as the transparent resin, air bubbles may be used as the light deflection region. The internal surface of the bubble formed inside the thermoplastic resin causes irregular reflection of light, and a light deflection function equivalent to or higher than that in the case where the light diffusion particles are dispersed can be exhibited. Therefore, the thickness of the light deflection layer can be further reduced.
Examples of such a light deflection layer include white PET and white PP. White PET is obtained by dispersing a resin incompatible with PET, fillers such as titanium oxide (TiO2) and barium sulfate (BaSO4) in PET, and then stretching the PET by a biaxial stretching method. It is formed by generating bubbles around the filler.

  Note that the light deflection layer made of a thermoplastic resin only needs to be stretched in at least one axial direction. This is because if it is stretched in at least one axial direction, bubbles can be generated around the filler.

  Examples of the thermoplastic resin include polyethylene terephthalate (PET), polyethylene-2,6-naphthalate, polypropylene terephthalate, polybutylene terephthalate, cyclohexanedimethanol copolymer polyester resin, isophthalic acid copolymer polyester resin, and spiroglycol copolymer polyester resin. , Polyester resins such as fluorene copolymerized polyester resins, polyolefin resins such as polyethylene, polypropylene, polymethylpentene, alicyclic olefin copolymer resins, acrylic resins such as polymethyl methacrylate, polycarbonate, polystyrene, polyamide, polyether, Polyester amide, polyether ester, polyvinyl chloride, cycloolefin polymer, acrylonitrile polyol copolymer And these copolymers as a component, or the like can be used a mixture of these resins are not particularly limited.

The thickness of the light deflection layer is preferably 1 μm to 1000 μm.
When the thickness of the light deflection layer is less than 1 μm, a sufficient light deflection effect cannot be obtained, which is not preferable. Further, when the thickness of the light deflection layer exceeds 1000 μm, the thickness of the base material also exceeds 1000 μm, so the total thickness of the light propagation layer 27 increases, and accordingly, the total thickness of the diffusion member 25 also increases. The optical sheet 11 is not preferable because it becomes thicker and heavier.

The light deflected by the light deflection element enters the light propagation layer 27, and the light transmitted through the light propagation layer 27 enters the diffusion base material 26.
The light propagation layer 27 has a plurality of light deflection elements on the back surface of the light propagation layer 27.
The diffusion member 25 includes a diffusion base material 26 and a light propagation layer 27, and is formed by superimposing the viewer side X surface of the light propagation layer 27 on the back surface side of the diffusion base material 26.

  The light propagation layer 27 preferably has a total light transmittance of 80% or more. If the total light transmittance is 80% or more, the luminance of the light emitted to the viewer side X is not lowered. On the contrary, when the total light transmittance is less than 80%, the luminance of the light emitted to the viewer side X is lowered, which is not preferable. The total light transmittance is a measured value based on JIS K7361-1.

  The light propagation layer 27 preferably has a haze value of 95% or less. A haze value exceeding 95% is not preferable because a sufficient light diffusion effect cannot be obtained even if a light deflection element is formed on the back surface of the light propagation layer 27. The haze value is a measured value based on JIS K7136.

  The material used for the light propagation layer 27 is preferably a transparent resin made of a thermoplastic resin. For example, polycarbonate resin, acrylic resin, fluorine acrylic resin, silicone acrylic resin, epoxy acrylate resin, polystyrene resin, cycloolefin polymer, Examples thereof include a methylstyrene resin, a fluorene resin, PET, polypropylene, and an acrylonitrile polyol copolymer. Further, the light propagation layer 27 may be extended in at least one axial direction.

  More preferably, the light propagation layer 27 does not contain light diffusing particles. This is because when the light diffusing particles are contained in the light propagation layer 27, the light diffusion effect by the light deflection element is weakened.

The light incident on the diffusion base material 26 is diffused by the diffusion base material 26 and diffused and applied to the optical layer 32.
The diffusion base material 26 preferably has a total light transmittance of 40% to 80%. When the total light transmittance is less than 40%, it is not preferable because the luminance of the emitted light toward the viewer side X is lowered. On the contrary, when the total light transmittance exceeds 80%, the diffusion performance is low. This is not preferable because it becomes insufficient and the uniformity of in-plane luminance is deteriorated.

  The diffusion base material 26 preferably has a haze value of 98% or more. When the haze value is less than 98%, the diffusion performance becomes insufficient and the uniformity of in-plane luminance is deteriorated, which is not preferable.

The diffusion base material 26 is formed by dispersing a light diffusion region in a transparent resin.
As the transparent resin, a thermoplastic resin, a thermosetting resin, or the like can be used. For example, a polycarbonate resin, an acrylic resin, a fluorine acrylic resin, a silicone acrylic resin, an epoxy acrylate resin, a polystyrene resin, or a cycloolefin polymer. , Methylstyrene resin, fluorene resin, polyethylene terephthalate (PET), polypropylene, acrylonitrile polyol copolymer, and the like can be used.

The light diffusion region is preferably made of light diffusion particles. This is because suitable diffusion performance can be easily obtained.
As the light diffusing particles, transparent particles made of an inorganic oxide or a resin can be used. As the transparent particles made of an inorganic oxide, for example, silica, alumina or the like can be used. In addition, transparent particles made of resin include acrylic particles, styrene particles, styrene acrylic particles and cross-linked products thereof, particles of melamine-formalin condensate, PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxy resin), FEP (tetra Fluoropolymer particles such as fluoroethylene-hexafluoropropylene copolymer), PVDF (polyfluorovinylidene), and ETFE (ethylene-tetrafluoroethylene copolymer), silicone resin particles, and the like can be used.
Moreover, you may use combining 2 or more types of transparent particles from the transparent particle described previously. Furthermore, the size and shape of the transparent particles are not particularly defined.

When the light diffusion particle is used as the light diffusion region, the thickness of the diffusion base material 26 is preferably 0.1 to 5 mm.
When the thickness of the diffusion substrate 26 is 0.1 to 5 mm, optimum diffusion performance and brightness can be obtained. On the other hand, if the thickness is less than 0.1 mm, the diffusion performance is insufficient, and if it exceeds 5 mm, the amount of resin is large and the luminance is reduced due to absorption.

In the case where a thermoplastic resin is used as the transparent resin, air bubbles may be used as the light diffusion region. The internal surface of the bubble formed inside the thermoplastic resin causes diffused reflection of light, and a light diffusing function equivalent to or higher than that when light diffusing particles are dispersed can be expressed. Therefore, the film thickness of the diffusion base material 26 can be made thinner.
Examples of such a diffusion base material 26 include white PET and white PP. White PET is obtained by dispersing a resin incompatible with PET, fillers such as titanium oxide (TiO2) and barium sulfate (BaSO4) in PET, and then stretching the PET by a biaxial stretching method. It is formed by generating bubbles around the filler.

  The diffusion base material 26 made of a thermoplastic resin may be stretched at least in the uniaxial direction. This is because if it is stretched in at least one axial direction, bubbles can be generated around the filler.

  Examples of the thermoplastic resin include polyethylene terephthalate (PET), polyethylene-2, 6-naphthalate, polypropylene terephthalate, polybutylene terephthalate, cyclohexanedimethanol copolymer polyester resin, isophthalic acid copolymer polyester resin, and spiroglycol copolymer polyester. Resins, polyester resins such as fluorene copolymer polyester resins, polyolefin resins such as polyethylene, polypropylene, polymethylpentene, and alicyclic olefin copolymer resins, acrylic resins such as polymethyl methacrylate, polycarbonate, polystyrene, polyamide, polyether , Polyester amide, polyetherester, polyvinyl chloride, cycloolefin polymer, acrylonitrile polyol polystyrene Copolymers to the body and these as a component, or the like can be used a mixture of these resins are not particularly limited.

When bubbles are used as the light diffusion region, the thickness of the diffusion base material 26 is preferably 25 to 500 μm.
When the thickness of the diffusion base material 26 is less than 25 μm, it is not preferable because the sheet is insufficiently squeezed and wrinkles are likely to occur when it is installed in a manufacturing process or display. In particular, when installed in a display, the display device 5 is generally installed with the display surface substantially parallel to the vertical direction with respect to the ground, so the optical sheet 11 installed in the display device 5 is also perpendicular to the ground. Installed approximately parallel to the direction. In this case, if the sheet is insufficiently squeezed as described above, the weight of the optical sheet 11 cannot be supported, and wrinkles are likely to occur. In addition, when the thickness of the diffusion base material 26 exceeds 500 μm, there is no particular problem in optical performance, but since the rigidity is increased, it is difficult to process into a roll shape, and the slit cannot be easily formed. Since the merit of the thinness obtained by comparison decreases, it is not preferable.

In the diffusion member 25 forming step of the present embodiment, first, the diffusion base material 26 and the light propagation layer 27 or the light deflection layer were laminated by a melt extrusion method using an extruder as shown in FIG. The diffusion member 25 is formed.
The extruder 70 is an apparatus including, for example, a hopper 71 for charging a molding resin, a screw 72 for extruding the resin while melting and kneading the resin, a T-die 73 for extruding the resin into a sheet shape, and the like.
According to this extruder 70, a transparent resin containing a diffusing agent for forming the diffusion base material 26 and a transparent resin for forming the light propagation layer 27 are melted, respectively, from the lower side of the drawing to the diffusion base material. 26 and the light diffusion laminate are laminated, the substrate sheet 80 can be formed by extrusion from the T die 73.
The base sheet 80 is conveyed in the illustrated horizontal direction, the nip roll 75 is brought into contact with the surface of the diffusion base 26, and an embossed shape for forming an uneven shape as a light deflection element on the surface of the light propagation layer 27. The nip roll 75 and the roll mold 74 are rotated and further conveyed in the right direction in the drawing.
Then, the concave / convex shape is transferred to the surface of the light propagation layer 27 by the roll mold 74, and the resin is solidified by cooling the resin together with the conveyance, so that the resin is solidified at the boundary between the diffusion base material 26 and the light propagation layer 27 Tightly bonded.
As described above, the diffusion member 25 is continuously formed.

In the above-described manufacturing method, the light deflection lens 28 can be formed on the surface of the light propagation layer 27 as a light deflection element by making the uneven shape into a unit lens shape. By simultaneously forming the shape of the light deflection lens 28 when manufacturing the light propagation layer 27, the manufacturing process can be further simplified, and the yield can be improved and the cost can be reduced.
Moreover, the diffusing member 25 may be extended in at least one axial direction.
By using the multilayer extrusion method, the manufacturing process can be simplified and made more efficient, and the manufacturing cost can be reduced.

The above manufacturing method is a manufacturing method of the diffusion member 25 having a multilayer structure including at least one light propagation layer 27 and one diffusion base material 26. However, the present invention is not limited thereto, and one or more light propagations are performed. A multilayer structure including the layer 27 and one or more diffusion substrates 26 may be employed.
For example, the light propagation layer 27, the diffusion base material 26, the diffusion base material 26, and the diffusion base material 26 may have a four-layer structure from the light source 1 side. In this case, by appropriately designing the diffusion intensity of the diffusion base material 26, the diffusion intensity can be increased without increasing the thickness of the diffusion base material 26, or the light emitted from the diffusion member 25 can be distributed to a desired light distribution. The distribution can be designed.

  Further, by using the above-described manufacturing method, a single-layer light propagation layer 27 and / or a single-layer diffusion base material 26 is manufactured, and the diffusion base material 26 and the diffusion base material 26 are bonded via a bonding layer 45 made of an adhesive or an adhesive. The light diffusing member 25 may be manufactured by laminating the light propagation layer 27. For example, as a method of bonding, the diffusion base material 26 and the light propagation layer 27 can be bonded using a generally used laminate or the like.

  In the case of the above configuration, as shown in FIG. 15, the light propagation layer 27 and the diffusion base material are formed by forming an uneven structure on the surface of the single layer light propagation layer 27 and / or the single layer diffusion base material 26. When bonding 26, the concavo-convex structure is directed to the boundary between the light propagation layer 27 and the diffusion base material 26, so that the air layer 30 can be formed at the boundary between the light propagation layer 27 and the diffusion base material 26. Become.

The bonding layer 45 is formed using urethane-based or acrylic-based resin or the like. One that is pressed and bonded in a one-pack type, one that is cured by heat or light, and one that is cured by mixing two liquids or a plurality of liquids can be used. Moreover, you may disperse | distribute a filler to the above-mentioned liquid. By dispersing the filler, the elastic modulus of the bonding layer 45 can be increased. By increasing the elastic modulus of the bonding layer 45, it is possible to prevent the bonding layer 45 from entering the region of the air layer 30, and the air layer 30 can be easily held.
You may apply | coat directly to an adhesion surface, and you may bond what was prepared as a dry film beforehand.

In the other diffusion member 25 forming process of the present embodiment, first, the diffusion member 25 having the diffusion base material 26 and / or the light propagation layer 27 is formed by injection molding using an injection molding machine 76 as shown in FIG. Can be formed.
The injection molding machine 76, for example, a hopper 71 for charging a molding resin, a screw 72 for transferring the resin by rotation, compressing heat exchange and plasticizing and melting, storing the plasticized and melted resin, and supplying it to the mold clamping device 81 A plasticizing device 78 having a nozzle 77 and the like, an operating mold 79b, a fixed mold 79a, a drive mechanism 82 for supporting and operating the molds 79a and 79b, and a solidified trace of the plasticized and melted resin are ejected. This is an apparatus provided with a mold clamping device 81 provided with a protruding mechanism 83 that protrudes the diffusion member 25 with a pin or the like and takes out the diffusion base material 26 and / or the light propagation layer 27 from the mold 79b.
According to this injection molding machine 76, in the plasticizer 78, the transparent resin or the transparent resin to which the diffusing agent is added is subjected to compression heat exchange to be plasticized and melted, and the molds 79a and 79b are closed. The diffusion resin 26 and / or the light propagation layer 27 can be formed by supplying molten resin to the substrate.
The diffusion base material 26 and / or the light propagation layer 27 are sandwiched in a pressed state by a mold having an uneven shape for forming an uneven shape on the surface.
Then, the concavo-convex shape is transferred to the surface of the diffusion base material 26 and / or the light propagation layer 27 by the molds 79a and 79b, and the transparent resin or the transparent resin added with the diffusing agent is cooled, so that the resin is solidified. Then, the diffusion base material 26 and / or the light propagation layer 27 are formed. After the diffusion base material 26 and / or the light propagation layer 27 is formed, the protrusion mechanism 83 is driven to project the diffusion base material 26 and / or the light propagation layer 27 with its eject pin or the like, and the diffusion base material 26 is ejected from the molds 79a and 79b. And / or the light propagation layer 27 is taken out.

In the above-described injection molding manufacturing method, it is possible to form the light deflection lens 28 on the surface of the light propagation layer 27 by making the uneven shape into the shape of the light deflection lens 28. By simultaneously forming the shape of the light deflection lens 28 when manufacturing the light propagation layer 27, the manufacturing process can be further simplified, and the yield can be improved and the cost can be reduced.
By using the injection molding method, a post-process for cutting the diffusion base material 26 and / or the light propagation layer 27 to a desired size can be omitted, and the yield can be improved.

  In addition, it can be produced using a casting polymerization method in which monomers, oligomers and the like are polymerized and molded in a mold. For example, you may shape | mold by heat-pressing with the type | mold using a metal or resin.

The light deflection lens 28 can also be formed on the surface 23a on the back side of the base 23 using a radiation curable resin such as a UV curable resin. For example, the light deflection lens 28 can be formed by UV molding on the back surface 23 a of the base material 23 after the base material 23 is formed as a plate-like member by an extrusion method. Alternatively, the light deflection lens 28 can be UV-molded on the back surface 23a of the base material 23 after the base material 23 is formed as a plate-like member by extrusion and integrated with the diffusion base material 26. .
Optical deflection lenses using PET (polyethylene terephthalate), PC (polycarbonate), PMMA (polymethyl methacrylate), COP (cycloolefin polymer), acrylonitrile styrene copolymer, etc. by injection molding or hot press molding. 28 can also be formed.

  Further, as shown in FIG. 17, the light deflection lens layer on which the light deflection lens 28 is formed is formed as a separate body, and the optical layer 32 and the light propagation layer 27 are formed via a bonding layer 45 made of an adhesive or an adhesive material. The light deflection lens 28 may be formed by bonding.

As a manufacturing method of the above-described light deflection lens 28 layer, molding is performed on the translucent substrate 33 using UV or radiation curable resin (the type is not particularly limited as long as the resin includes a material curable by UV or radiation). May be. Here, as the translucent substrate 33, PET (polyethylene terephthalate), PP (polypropylene), PC (polycarbonate) PMMA (polymethyl methacrylate), benzyl methacrylate, MS resin, other acrylic resins, or COP (cycloolefin) It is preferable to use an optically transparent member such as a polymer.
Alternatively, the technology using PET (polyethylene terephthalate), PC (polycarbonate), PMMA (polymethyl methacrylate), COP (cycloolefin polymer), PAN (polyacrylonitrile copolymer), AS (acrylonitrile styrene copolymer), etc. You may form by the extrusion molding method well-known in the field | area, the injection molding method, or the hot press molding method.

  The light diffused by the diffusing member 25 enters the optical layer 32, is condensed, and is emitted to the viewer side X.

As shown in FIG. 1, in the optical sheet 11, the optical layer 32 and the diffusion member 25 are integrated.
The optical layer 32 includes a light transmissive substrate 34, a light transmissive substrate unit lens 36, and a light mask 40.

  A plurality of light transmission substrate unit lenses 36 are arranged at a constant pitch on the viewer side X surface of the light transmission substrate 34.

  The light transmitting base unit lens 36 is formed on the viewer-side X surface of the light-transmitting base 34 so that the light passing through the diffusing member 25 is condensed on the viewer side X, The brightness of X can be improved.

The viewer side X and the back side of the light-transmitting substrate 34 are substantially flat surfaces, a plurality of light masks 40 are formed, and the diffusion member 25 is joined.
As the material of the light transmissive substrate 34, a thermoplastic resin, a thermosetting resin, or the like can be used, and the material used for the diffusion member 25 may be used. Generation | occurrence | production of curvature can be suppressed by joining the material used for the diffusion member 25. FIG.

  In addition, when unit lenses are formed on one surface and the other surface of one member, moire interference fringes may occur, and the optical sheet 11 has a viewer side X surface (outgoing surface) of the light transmitting substrate 34. ) Is formed, and the light deflection lens 28 is formed on the rear surface (incident surface) of the optical sheet 11. The light transmission substrate unit lens 36, the light deflection lens 28, Since the diffusion base material 26 is inserted between the moiré interference fringes due to the above-described factors, it can be prevented.

  The shape of the unit lens 36 for the light transmissive substrate is a convex curved surface shape, and has a second top portion having an arcuate surface and a second inclined surface extending from the second top portion to the light transmissive base material 34. Moreover, the unit lens 36 for light transmissive base materials is formed so that the distance between the opposing second inclined surfaces gradually decreases toward the second top. Furthermore, the light transmission base unit lenses 36 are spaced apart by the valleys 13 and formed at a constant pitch.

A plurality of light masks 40 and light transmission openings 42 that separate the light masks 40 are provided between the light transmissive substrate 34 and the diffusion member 25. The pitch of the light mask 40 and the light transmission openings 42 is substantially the same as the pitch of the light transmission base unit lenses 36.
The position of the optical mask 40 is formed at a position corresponding to the position of the valley portion 13. Therefore, the position of the light transmission opening 15 is provided at a position corresponding to the second apex of the light transmission substrate unit lens 36.

  The light mask 40 is made of a material that does not transmit light, and is formed at a position corresponding to the position of the valley portion 13 that separates the light transmitting base unit lens 36 formed on the surface on the viewer side X. Therefore, the light incident on the optical layer 32 passes through the light transmitting opening 15 formed away from the optical mask 40 and enters the light transmitting base unit lens 36, and thus passes through the diffusion member 25. The emitted light is efficiently emitted in the front direction (viewer side X).

  Furthermore, the optical mask 40 can be comprised from light reflective members, such as a metal material and a white reflective material, for example. In this case, the light reflected by the light mask 40 is returned to the diffusing base material 26 constituting the diffusing member 25, is again light diffused by the diffusing base material 26, and then is emitted to the viewer side X. By repeating this process, almost all the light from the light source 1 can be emitted to the viewer side X.

  The optical sheet 11 is formed by bonding the diffusion member 25 to the four sides of the back side surface of the optical layer 32 on which the optical mask 40 is formed as described above, with the bonding layer 45 having an adhesive layer or an adhesive layer. Can do.

  The light transmission substrate unit lens 36 is formed by using, for example, PET, PC, PMMA, COP (cycloolefin polymer), acrylonitrile styrene copolymer, etc., a well-known extrusion molding method, injection molding method, or hot press molding method. Formed by. In this case, the light-transmitting substrate 34 and the light-transmitting substrate unit lens 36 may be made of different substrates of different materials, or may be formed of a single substrate made of the same material. Good. Further, the incident surface of the light transmissive substrate 34 may be molded with a step as shown in FIG. 18, for example. Further, the unit lens 36 for the light transmissive substrate is molded using, for example, UV or radiation curable resin (the type is not particularly limited as long as the resin includes a material curable by UV or radiation) on the light transmissive substrate 34. It may be done.

The optical mask 40 may be directly formed on the incident surface of the light transmitting substrate 34 by printing or vapor deposition, but it is preferable to form the optical mask 40 by transfer, for example.
When the optical mask 40 is formed by transfer, for example, a photosensitive resin film is attached to the incident surface of the light transmissive substrate 34 and is exposed via the light transmissive substrate unit lens 36 and the light transmissive substrate 34. The photosensitive resin film is exposed to ultraviolet rays. Thereby, the adhesive force of the photosensitive resin film is reduced only in the focal point of the light transmitting base unit lens 36 and the region in the vicinity thereof by the light condensing action of the light transmitting base unit lens 36. Then, the laminated body of the light transmissive base material 34 and the photosensitive resin film is pressed against the optical mask 40 formed on the release paper, and then the laminate is peeled from the release paper. In this way, the optical mask 40 having the light transmitting opening 42 at the focal point of the light transmitting base unit lens 36 and the region in the vicinity thereof is obtained.
Each light transmitting opening 42 of the light mask 40 formed in this way is arranged so that the central axis of each light transmitting opening 42 substantially coincides with the optical axis of the corresponding light transmitting base unit lens 36. It is formed.

  Even when the printing method is used, as described above, for example, as shown in FIG. 18, a light mask can be easily printed by providing a step on the incident surface when the light-transmitting substrate 34 is manufactured. 40 can be formed. However, in order to make the central axis of each light transmitting opening 42 of the light mask 40 substantially coincide with the optical axis of the light transmitting base unit lens 36, the position where the light transmitting base unit lens 36 and the step are formed is provided. Relative alignment is required.

  Further, the optical layer 32 of the present invention may be laminated and integrated by providing a plurality of fixing elements 44 between the light transmitting base material 34 and the diffusing member 25 as shown in FIG. In the case of stacking and integration, a bonding layer 45 may be provided.

Between the light transmissive substrate 34 and the diffusing member 25, a plurality of fixing elements 44 and a light transmitting opening 42 that separates the fixing elements 44 are provided. When the area of the fixing element 44 that contacts the incident surface of the light-transmitting substrate 34 is S1, the area that contacts the incident surface of the light transmitting opening is S2,
It is preferable to satisfy S1 / (S1 + S2) ≦ 0.1.
If the above relationship is satisfied, the positional relationship between the fixing element 44 and the lens for the light transmissive substrate 34 is not particularly limited, and can be appropriately designed.
If the above relationship is not satisfied, the ratio of the amount of light incident on the fixed element 44 increases. The light incident on the fixed element 44 is more likely to be scattered and become stray light as compared with the light transmitted through the light transmission opening, so that the light use efficiency is lowered.

  The shape of the light transmission substrate unit lens 36 when the fixing element 44 is provided may be a prism array in which a plurality of linear prisms each having a concave or convex cross section are arranged in parallel. For example, as shown in FIG. 19A, a prism array in which a plurality of triangular prisms having a cross section of 90 degrees in apex is arranged in parallel may be used.

  When the fixing element 44 is provided, the shape of the unit lens 36 for the light-transmitting substrate is a polygon having a concave or convex cross section, and a plurality of linear prisms each having a curved top portion are substantially parallel to each other. A side-by-side prism array may be used. For example, it may be a prism array in which a plurality of prisms having a triangular cross section with an apex angle of 90 degrees and rounded apexes are arranged in parallel. By having a round apex angle, it is possible to improve the durability against scratches and rubbing on the prism structure.

The shape of the light transmitting base unit lens 36 when the fixing element 44 is provided may be a lens array in which a plurality of lenses having a substantially circular or substantially elliptical cross section are arranged in parallel. For example, an aspherical shape obtained by applying shape correction by a high-order term algorithm based on an elliptical shape may be used. In this case, by changing the shape correction, it is possible to appropriately design the light distribution of the emitted light.
By making the cross section substantially circular or substantially elliptical, it is possible to emit light at a high angle, that is, reduce so-called side lobes, as compared with a polygonal prism.

The shape of the light transmitting base unit lens 36 when the fixing element 44 is provided may be a structure in which a plurality of prisms having a polygonal pyramid structure are arranged in a lattice pattern. For example, a plurality of prisms having a regular quadrangular pyramid shape may be arranged in a lattice shape. Alternatively, a plurality of prisms having a regular triangular pyramid shape may be arranged in a lattice pattern. In this case, it is possible to appropriately design the light distribution by providing the angle of the apex angle or rounding the apex angle.
By arranging a plurality of prisms having a polygonal pyramid structure in a lattice shape, side lobes can be reduced and light can be condensed in a two-dimensional direction.

The shape of the light transmission substrate unit lens 36 when the fixing element 44 is provided may be a structure in which a plurality of prisms having a conical structure are arranged in a lattice shape. For example, a plurality of prisms having a conical shape with an apex angle of 90 degrees may be arranged in a lattice shape. In this case, it is possible to appropriately design the light distribution by providing the angle of the apex angle or rounding the apex angle.
By arranging a plurality of prisms having a polygonal pyramid structure in a lattice shape, side lobes can be reduced and light can be condensed in a two-dimensional direction.

The shape of the light transmitting base unit lens 36 when the fixing element 44 is provided includes first and second lens arrays provided on one surface of the lens sheet, and the first lens array is arranged on the one surface. A plurality of first lenses extending along a direction and arranged parallel to each other, and the second lens array extends along a direction orthogonal to the first lens array direction on the one surface. A structure may be provided that includes a plurality of second lenses arranged in parallel to each other, and the second lens includes a plurality of sub-lenses arranged in the valley portions 13 of the plurality of first lenses. The lens array and sub-lens described above may be a prism array or a sub-prism.
For example, the first prism may be a triangular prism having a vertical angle of 90 degrees, and the second prism may be a triangular prism having a vertical angle of 90 degrees. In this case, it is possible to appropriately design the light distribution by providing the apex angle, rounding the apex angle, or changing the lens shape to a substantially circular or oval cross section instead of a prism shape. .
With the above-described structure, light can be condensed in a two-dimensional direction.

The shape of the light transmission substrate unit lens 36 when the fixing element 44 is provided may be a structure in which a plurality of microlenses having a substantially semi-spherical shape or a substantially semi-elliptical spherical shape are arranged in a lattice shape. For example, an aspherical shape obtained by correcting the shape by a high-order term algorithm with a semi-elliptical sphere shape as a reference may be used. In this case, by changing the shape correction, it is possible to appropriately design the light distribution of the emitted light.
By making it a substantially semi-spherical shape or a substantially semi-elliptical sphere shape, side lobes can be reduced and light can be condensed in a two-dimensional direction.

  When the fixing element 44 is provided, the shape of the unit lens 36 for the light transmitting substrate is such that an inverted V-shaped recess is formed at the top of the substantially circular or substantially elliptical cross section as shown in FIG. It may be a thing. By forming the recesses, the light can be retroreflected to improve the light utilization efficiency.

  When the fixing element 44 is provided, the shape of the light transmitting base unit lens 36 is preferably a shape in which the cross-sectional shape orthogonal to the sheet surface of the lens sheet is substantially symmetric. When the shape is substantially symmetric, the distribution of the light emitted from the lens sheet is also substantially symmetric. In this case, the brightness in the viewing direction of the specific direction does not change, and a preferable image is obtained.

  Further, the shape of the unit lens 36 for the light transmissive substrate described above may be a shape in which the cross-sectional shape orthogonal to the surface of the light transmissive substrate 34 is asymmetric as shown in FIG. In the case of an asymmetric shape, the distribution of the emitted light from the light transmitting base unit lens 36 is also asymmetric. Depending on the installation location of the display device 5, there are cases in which viewing is not performed from above or below the screen. In that case, it is possible to darken the non-viewing direction and make the viewing direction brighter, and by making the shape of the unit lens 36 for the light transmitting base material an asymmetrical shape, a desired light distribution can be obtained. Can be obtained. As an example of the asymmetrical shape, there is an asymmetrical prism in which one of the cross-sectional shapes is a curved shape, the other is formed in a linear shape, and the curved shape and the linear shape are connected with a round shape.

  The shape of the above-described fixing element 44 is not limited as long as a light transmitting opening can be secured between the light transmitting base material 34 and the diffusing member 25. In order to prevent light loss, it is preferable to use a material that absorbs less light.

  In addition, as shown in FIG. 20, the light transmitting base material 34 and the fixing element 44 described above may be integrally molded and laminated with the diffusion member 25. In the case of stacking and integration, the bonding layer 45 may be provided in the case of stacking and integration.

  Further, as shown in FIG. 20, the light transmitting base unit lens 36 may have a lens shape formed on the back side (incident surface) of the light transmitting base material 34, or a light transmitting base formed on the incident surface. The material unit lens 36 is preferably located between the light transmitting opening 42 formed between the light masks 40 or between the integrally formed fixing elements 44. Moreover, the thing of a structure like FIG. 21 may be sufficient.

The unit lens 36 for the light transmitting base material is made of, for example, a well-known extrusion molding method, injection molding method, or hot press molding method using PET, PC, PMMA, COP (cycloolefin polymer), acrylonitrile styrene copolymer or the like. Formed by. In this case, the light-transmitting substrate 3441 and the light-transmitting substrate unit lens 36 may be made from different substrates of different materials, for example, composed of one substrate made of the same material. May be. The unit lens 36 for the light transmissive substrate is formed using, for example, UV or radiation curable resin on the light transmissive substrate 34 (the type is not particularly limited as long as the resin includes a material curable by UV or radiation). It may be done.
In addition, the fixing element 44 may be formed simultaneously with the formation of the unit lens 36 for the light transmitting substrate, and the light transmitting substrate 34 and the fixing element 44 may be integrated.

  The optical sheet 11 formed as described above is warped by the heat generated from the light source 1. When warping occurs, a region where the distance between the light source 1 and the optical sheet 11 is short and a region where the distance is long are generated, causing a problem of uneven brightness in the display screen. In addition, there is a problem in that the warped optical sheet 11 applies pressure to the liquid crystal display unit 21 that is the display unit 21 to cause distortion in the display image.

An example of the thickness of the optical sheet 11 is 2.4 mm (each thickness is as follows, the optical layer 32 is 0.2 mm, the diffusion base material 26 is 1 mm, the light propagation layer 27 is 1 mm, and the light deflection lens 28 is 0.2 mm). ). An example of the thickness of the light transmissive substrate 34 in the optical layer 32 is 75 μm. In the above example, the diffusion member 25 is made of, for example, polycarbonate, polystyrene, MS resin, etc., and the linear expansion coefficients of the polycarbonate, polystyrene, and MS resin are 6.7 × 10 ⁻⁵ (cm / cm / ° C.), respectively. 7 × 10 ⁻⁵ (cm / cm / ° C.) and 7 × 10 ⁻⁵ (cm / cm / ° C.). On the other hand, the light transmissive substrate 34 is made of, for example, PET, and the linear expansion coefficient of PET is 2.7 × 10 ⁻⁵ (cm / cm / ° C.), and the linear expansion coefficient of the diffusing member 25 is larger. Therefore, when the optical sheet 11 receives heat and deforms, warpage occurs on the optical layer 32 side.

Therefore, in the optical sheet 11 of the present invention, as shown in FIG. 22, each light transmitting opening 42 in which both ends of the optical layer 32 are opened, or a striped air layer 30 in which both ends are opened in the diffusion member 25. Form.
By forming the light transmission openings 42 and the air layer 30 described above, an air flow is generated and the optical sheet 11 can be cooled.

  As shown in FIG. 22A, by opening both end faces 16R, 16L of each light transmitting opening 42 of the optical layer 32, the air flow in each light transmitting opening 42 is improved. Therefore, the optical sheet 11 can be efficiently cooled. Therefore, even when the liquid crystal display device 5 is used continuously for a long time, it is possible to prevent warpage or peeling due to thermal deformation of the optical sheet 11 and thus to prevent deterioration in image quality. Basically, since the air flow in each light transmission opening 42 is improved, no deterioration in image quality due to warping is recognized regardless of the cross-sectional area of the end face.

  Thus, by opening both end faces of both end faces 16R and 16L of each light transmitting opening 42 of the optical layer 32, the configuration of the diffusing member 25 (in order from the back side, the light deflection lens 28: 0.2 mm). No warpage occurred in the thickness, the light propagation layer 27: 1 mm thickness, and the diffusion base material 26: 1 mm thickness). Moreover, in the structure where the thickness of each layer of the above-mentioned structure differs, it did not generate | occur | produce if the thickness of the diffusion member 25 was 4 mm or less.

Specifically, when the pressure loss ΔP of the air flowing through each light transmission opening 42 is 0 (Pa) <ΔP <2.2 × 10 ² (Pa), each light transmission opening 42 is provided. Both end faces 16R and 16L are opened. By opening both the end faces 16R and 16L in this way, the flow of air in each light transmission opening 42 is improved, and the optical sheet 11 can be efficiently cooled. ΔP = 0 means that the air entering the light transmitting opening 42 is not subjected to friction from the wall surface of the light transmitting opening 42 and there is no internal friction of the air itself. State.
In general, as the stripe length S increases, the air flow in each light transmission opening 42 tends to deteriorate, so that the stripe length S is longer than that when the stripe length S is longer than the vertical dimension of the optical sheet 11. The one shorter than the vertical dimension of the optical sheet 11 is less susceptible to thermal deformation. For this reason, it is more preferable to use the optical sheet 11 in which the stripe length S is shorter than the vertical dimension of the optical sheet 11.
The basis of the stripe length S described above and the allowable pressure loss ΔP will be described with reference to FIG.
In order for air to flow into the air layer 30 of the light transmission opening 42, the air pressure P1 at the inlet of the air layer 30, that is, the open end surface of the light transmission opening 42, the inside of the air layer 30, That is, air does not sufficiently convect in the air layer 30 unless the pressure loss ΔP (= P1−P2), which is the difference from the pressure P2 inside the light transmitting opening 42, is not less than a certain value. Here, if there is not sufficient air convection in the light transmission opening 42, heat release is lost, the optical sheet 11 becomes high temperature, and in some cases, thermal deformation occurs.
Next, the pressure loss ΔP of the air flowing through the light transmission opening 42 was evaluated using a model formula for a circular pipe. However, as shown in FIG. 6, the cross-sectional shape at the end face of the light transmission opening 42 is not a circle but a rectangle.
4 × (cross-sectional area of fluid flow) / (length around solid wall in contact with fluid)
The pressure loss ΔP is calculated using the equivalent diameter De of the cross section of the light transmission opening 42 obtained by the above. From the above formula, when the lengths of the rectangular sides at the end face of the light transmitting opening 42 are a and b, respectively,
The equivalent diameter De = 2ab / (a + b).
At this time, the average flow velocity of the air passing through the air layer 30 is as follows.

The pressure loss ΔP is expressed as follows using the Hagen-Poiseuille equation. From this, it can be seen that the pressure loss ΔP = 32 μVaveS / De ² .

However, in Formula 1 and Formula 2,
ΔP: Pressure loss De: Equivalent diameter Vave: Average air flow velocity ρ: Air density S: Stripe length Vmax: Maximum value of air flow rate r ₀ : Radius in the case of a circular pipe.
The backlight unit 13 whose both end faces were opened in the light transmission opening 42 of the optical sheet 11 was actually used for various sizes of the display, and the warp due to thermal deformation of the optical sheet 11 was observed. As a result, even when used in a 100-inch display, which is the maximum screen size of a standard liquid crystal display, no warping or peeling occurred. In the case of a 100-inch display, the stripe length S corresponds to 300 (cm). The threshold value α of the pressure loss ΔP in this case is the same as when only one end face of the light transmission opening 42 is opened.
Air viscosity μ = 18.86 × 10 ⁻⁶ (Pa · sec) (40 ° C.)
Average air velocity Vave = 0.06 (m / sec) (40 ° C.)
Equivalent diameter De = 2 × 10 × 42 / (10 + 42) (× 10 ⁻⁵ m)
Is used to calculate the pressure loss ΔP = 2.2 × 10 ² (Pa) as the threshold value α.
As a result, when both ends of the light transmission opening 42 are opened, if the range of the pressure loss ΔP is 0 (Pa) <ΔP <2.2 × 10 ² (Pa), air convection is sufficient. It can be seen that no warpage or peeling due to thermal deformation of the optical sheet 11 occurs.
As described above, in the backlight unit 13 according to the embodiment of the present invention, the convection of the air inside each light transmission opening 42 is sufficient by designing the backlight unit 13 to be within the threshold value α of the pressure loss ΔP. Since the heat dissipation of the optical sheet 11 can be promoted, even when the liquid crystal display device 5 is used continuously for a long time, the warp and peeling due to the thermal deformation of the optical sheet 11 are prevented, and the image quality is improved. It is possible to prevent the decrease of

Further, the air flow described above can also be generated in the striped air layer 30 formed on the diffusion base material 26 as shown in FIGS.
For example, as shown in FIG. 24A, a concave-convex structure is formed on the viewer side X of the diffusion base material 26, and the optical layer 32 is laminated and integrated with the bonding layer 45 in a state where the air layer 30 is secured. May be. When warpage occurs due to heat from the light source 1 at the boundary between the diffusion base material 26 and the optical layer 32, the positional relationship between the optical mask 40 or the fixing element 44 of the optical layer 32 is coarse on the surface of the optical sheet 11. Unevenness occurs, and there is a problem that it is visually recognized as unevenness of brightness on the screen. By forming the air layer 30 at the boundary portion between the diffusion base material 26 and the optical layer 32, the boundary portion between the diffusion base material 26 and the optical layer 32 is cooled, and the optical mask 40 or the fixing element 44 of the optical layer 32 is cooled. It becomes possible to prevent uneven density on the surface of the optical sheet 11.
Alternatively, as shown in FIG. 24B, an uneven structure may be formed on the back side of the diffusion base material 26, and the air layer 30 may be formed at the boundary between the diffusion base material 26 and the light propagation layer 27. . Since the diffusion base material 26 and the light propagation layer 27 have higher structural strength than the optical layer 32, the air layer 30 can be easily held.
Furthermore, as shown in FIG. 25, the concavo-convex structure is formed on both surfaces of the diffusion base material 26, and the air layer 30 is formed at the boundary between the diffusion base 26 and the optical layer 32 and at the boundary between the light propagation layer 27. May be. As described above, by forming the air layer 30 on both surfaces of the diffusion base material 26, it is possible to increase the area where the air flow is generated, and the cooling effect is enhanced.
As shown in FIG. 26, an air layer 30 may be formed inside the diffusion base material 26. Since the structural strength inside the diffusion base material 26 is large, it is easier to hold the air layer 30.

The air layer 30 can also be formed on the light propagation layer 27.
For example, as shown in FIG. 27A, an uneven structure may be formed on the back side of the light propagation layer 27, and the air layer 30 may be formed at the boundary between the light propagation layer 27 and the light deflection element. . An air layer 30 is formed on the back side of the light propagation layer 27 closest to the light source 1 side which is a heat generation source, and an air flow is generated on the back side of the light propagation layer 27 to cool the light propagation layer. Heat transfer from the back side of the layer 27 to each layer in the viewer side X direction can be prevented.
Alternatively, as shown in FIG. 27 (b), an uneven structure is formed on the viewer side X of the light propagation layer 27, and the air layer 30 is formed at the boundary between the diffusion base material 26 and the light propagation layer 27. Also good. Since the diffusion base material 26 and the light propagation layer 27 have a higher structural strength than the case where an uneven structure is formed on the back side of the light propagation layer 27, the air layer 30 can be easily held.
In addition, as shown in FIG. 28, a concavo-convex structure is formed on both surfaces of the light propagation layer 27, and the air layer 30 is formed at the boundary between the light propagation layer 27 and the diffusion base material 26 and at the boundary between the light deflection elements. You may form. As described above, by forming the air layer 30 on both surfaces of the light propagation layer 27, it is possible to increase the area where the air flow is generated, and the cooling effect is enhanced.
As shown in FIG. 29, an air layer 30 may be formed inside the light propagation layer 27. Since the structural strength inside the light propagation layer 27 is large, it is easier to hold the air layer 30.

  The air layer 30 may be formed on both the diffusion base material 26 and the light propagation layer 27. By forming the air layer 30 on both the diffusion base material 26 and the light propagation layer 27, it is possible to increase the region where the air flow is generated, and the cooling effect is enhanced.

The cross-sectional shape of the air layer 30 is not particularly limited as long as an air flow is generated.
For example, as shown in FIG. 30, the cross-sectional shape of the air layer 30 is a polygonal shape such as a trapezoidal shape shown in FIG. 30A, a triangular shape shown in FIG. 30B, or a rectangular shape shown in FIGS. A shape having a curve such as a circle, an ellipse, a circle, or a part of an ellipse shown in FIG. In the case of a triangular shape, an isosceles triangle is more preferable because it is easy to mold and has molding stability. Moreover, not only the substantially symmetric shape as described above but also an asymmetric shape may be used.

It is preferable that the optical sheet 11 has a size of 32 inches or more and has a larger horizontal dimension than a vertical dimension.
Since the optical sheet 11 has a large dimension in the horizontal direction, the warp of the optical sheet 11 occurs more strongly in the horizontal direction than in the vertical direction. By forming the striped air layer 30 in the horizontal direction, an air flow is generated in the horizontal direction, and a cooling effect is generated in the horizontal direction in which the warp is strongly generated. Therefore, the warp of the optical sheet 11 is more effective. Can be prevented. In particular, the cooling effect is prominent when the ratio of the vertical dimension of the optical sheet 11 to the horizontal dimension is 1.2 <(horizontal dimension / vertical dimension) <1.8.
Further, when the light polarizing lens 28 is formed by arranging stripe lenses, the horizontal direction of the optical sheet 11 can be reduced by making the stripe direction substantially coincide with the horizontal direction of the optical sheet 11. Therefore, the warp of the entire optical sheet 11 can be more effectively prevented.

  The air layer 30 may be provided in the vertical direction of the optical sheet 11. In the above case, the average air flow velocity Vave is increased due to the convection effect of heat, so that the air flow becomes efficient and the cooling effect can be enhanced.

The air layer 30 may be provided in both the vertical direction and the horizontal direction of the optical sheet 11 and orthogonal to each other.
In the above-described case, the air flow changes from the downward direction to the upward direction and from the horizontal direction to the upward direction due to the convection effect, and air entering from the horizontal direction flows more efficiently upward, so that the cooling effect is enhanced.

The direction of the light transmission opening 42 and the direction of the air layer 30 may be provided in parallel. In the case where the light transmitting opening 42 and the air layer 30 are provided in parallel, if the size of the cross-sectional area of the air layer 30 is the same as that of the light transmitting opening 42, only the light transmitting opening 42 is provided. Compared with the case of creating an air flow, twice as many air flows can be created. Therefore, no warping or peeling occurs even with a pressure loss ΔP corresponding to a case where the stripe length S is doubled to 600 cm. In this case, if the range of the pressure loss ΔP is 0 (Pa) <ΔP <4.4 × 10 ² (Pa), the convection of air is sufficient, and the warp or peeling due to thermal deformation of the optical sheet 11 does not occur. I understand that.
Further, the direction of the light transmission opening 42 and the direction of the air layer 30 may be provided orthogonal to each other.

  When the housing of the display device 5 has a heat removal mechanism, the average air flow velocity Vave can be increased, so that warping or peeling due to thermal deformation of the optical sheet 11 does not occur even if the pressure loss ΔP is increased.

(Example 1)
The light deflection lens 28 (pitch: 140 μm, lens height: 70 μm), the light propagation layer 24 (thickness: 1 mm), and the diffusion base material 26 (thickness: 2 mm) in the form of a triangular prism having a round shape are arranged in order from the back side. In the structure, a transfer method is performed in order from the light source side to the viewer side X of the diffusion member 25 made by extrusion molding using polycarbonate as a material, through a bonding layer 45 using an acrylic adhesive. A light mask 40 (material: TiO2, thickness: 10 μm), a light transmission opening 42 (cross section height: 10 μm, cross section width: 42 μm), a light transmission substrate 34 (material: PET, (Thickness: 75 μm), and an optical layer 32 of a light transmission substrate unit lens 36 (pitch: 140 μm, lens height: 70 μm) which is an aspherical lens shape molded by UV molding method, and is integrated 37 I This is an inch-sized optical sheet 11. When the liquid crystal display device was installed in the liquid crystal display device and moved for 24 hours, there was no problem due to the warp of the optical sheet 11.
(Comparative Example 1)
In this example, the influence which the cross-sectional area difference of the opening part 42 for light transmission which comprises the optical sheet 11 has on the curvature of optical sheet 11 itself was confirmed.
The light deflection lens 28 (pitch: 140 μm, lens height: 70 μm), the light propagation layer 24 (thickness: 1 mm), and the diffusion base material 26 (thickness: 2 mm) in the form of a triangular prism having a round shape are arranged in order from the back side. In the structure, a transfer method is performed in order from the light source side to the viewer side X of the diffusion member 25 made by extrusion molding using polycarbonate as a material, through a bonding layer 45 using an acrylic adhesive. A light mask 40 (material: TiO2, thickness: 2 μm), a light transmission opening 42 (cross section height: 2 μm, cross section width: 30 μm), a light transmission substrate 34 (material: PET, (Thickness: 75 μm), and an optical layer 32 of a light transmission substrate unit lens 36 (pitch: 140 μm, lens height: 70 μm) which is an aspherical lens shape molded by UV molding method, and is integrated 37 inch This is an optical sheet 11 having a size. When the liquid crystal display device was moved for 24 hours after being installed in the liquid crystal display device, a problem due to warpage of the optical sheet 11 occurred.
(Example 2)
The light deflection lens 28 (pitch: 140 μm, lens height: 70 μm), the light propagation layer 24 (thickness: 1 mm), and the diffusion base material 26 (thickness: 2 mm) in the form of a triangular prism having a round shape are arranged in order from the back side. In the structure, the fixed element in order from the light source side to the viewer side X of the diffusion member 25 made by extrusion molding using polycarbonate as a material, through the bonding layer 45 using an acrylic adhesive 40 (thickness: 40 μm), light-transmitting opening 42 (cross-sectional height: 40 μm, cross-sectional area width: 240 μm), light-transmitting substrate 34 (thickness: 200 μm), for a light-transmitting substrate having an aspheric lens shape 37-inch size, which is a structure in which the optical layer 32 made by extrusion molding is laminated and integrated using polycarbonate which is a structure of the unit lens 36 (pitch: 140 μm, lens height: 70 μm). This is an optical sheet 11. When the liquid crystal display device was installed in the liquid crystal display device and moved for 24 hours, there was no problem due to the warp of the optical sheet 11.
(Comparative Example 2)
In this example, the influence when the difference when the thickness of the diffusing member 25 constituting the optical sheet 11 exceeds 4 mm affects the warpage of the optical sheet 11 itself was confirmed.
In order from the back side, the rounded triangular prism-shaped light deflection lens 28 (pitch: 140 μm, lens height: 70 μm), light propagation layer 24 (thickness: 2 mm), diffusion base material 26 (thickness: 2 mm) In the structure, a transfer method is performed in order from the light source side to the viewer side X of the diffusion member 25 made by extrusion molding using polycarbonate as a material, through a bonding layer 45 using an acrylic adhesive. A light mask 40 (material: TiO2, thickness: 2 μm), a light transmission opening 42 (cross section height: 2 μm, cross section width: 30 μm), a light transmission substrate 34 (material: PET, (Thickness: 75 μm), and an optical layer 32 of a light transmission substrate unit lens 36 (pitch: 140 μm, lens height: 70 μm) which is an aspherical lens shape molded by UV molding method, and is integrated 37 inch This is an optical sheet 11 having a size. When the liquid crystal display device was moved for 24 hours after being installed in the liquid crystal display device, a problem due to warpage of the optical sheet 11 occurred.
(Example 3)
Joining using an acrylic adhesive on the light deflection lens 28 (material: polycarbonate, pitch: 140 μm, lens height: 70 μm) having a rounded triangular prism shape formed by extrusion molding in order from the back side. A striped air layer 30 (cross-sectional area height: 10 μm) formed at the boundary between the light deflection lens 28 and the light propagation layer 24, which is formed by laminating and integrating the light propagation layer 24 having an uneven structure via the layer 45. , Cross-sectional area width: 42 μm), light propagation layer 24 (material: polycarbonate, thickness: 1 mm), and diffusion base material 26 (material: polycarbonate, thickness: 2 mm). A photomask 40 (material: TiO2, thickness: 10 μm) formed on the viewer side X in order from the light source side through a bonding layer 45 using an acrylic adhesive. ), Light transmission opening 42 (cross-sectional area height: 10 μm, cross-sectional area width: 42 μm), light-transmitting substrate 34 (material: PET, thickness: 75 μm), aspherical lens shape molded by UV molding method This is an optical sheet 11 having a size of 37 inches, which is a configuration in which an optical layer 32 of a certain unit lens 36 for light transmitting substrate (pitch: 140 μm, lens height: 70 μm) is laminated and integrated. When the liquid crystal display device was installed in the liquid crystal display device and moved for 24 hours, there was no problem due to the warp of the optical sheet 11.
(Example 4)
Joining using an acrylic adhesive on the light deflection lens 28 (material: polycarbonate, pitch: 140 μm, lens height: 70 μm) having a rounded triangular prism shape formed by extrusion molding in order from the back side. A striped air layer 30 (cross-sectional area height: 5 μm) formed at the boundary between the light deflection lens 28 and the light propagation layer 24, which is formed by laminating and integrating the light propagation layer 24 having an uneven structure via the layer 45. , Cross-sectional area width: 42 μm), light propagation layer 24 (material: polycarbonate, thickness: 1 mm), and diffusion base material 26 (material: polycarbonate, thickness: 2 mm). A photomask 40 (material: TiO2, thickness: 5 μm) formed on the viewer side X in order from the light source side through the bonding layer 45 using an acrylic adhesive, Light having a light transmission opening 42 (cross section height: 5 μm, cross section width: 42 μm), light transmitting substrate 34 (material: PET, thickness: 75 μm), aspherical lens shape molded by UV molding method This is an optical sheet 11 having a size of 37 inches, which is a configuration in which the optical layers 32 of the transmission base unit lens 36 (pitch: 140 μm, lens height: 70 μm) are laminated and integrated. When the liquid crystal display device was installed in the liquid crystal display device and moved for 24 hours, there was no problem due to the warp of the optical sheet 11. By providing the air layer 30 according to the fourth embodiment, a sufficient cooling effect can be obtained even when the cross-sectional areas of the air layer 30 and the light transmission opening 42 are reduced, and the problem of warpage does not occur. It was confirmed.

(Comparative Example 3)
In this example, the influence which the difference in the magnitude | size of the cross-sectional area of the air layer 30 and the light transmission opening part 42 which comprises the optical sheet 11 has on the curvature of optical sheet 11 itself was confirmed.
Joining using an acrylic adhesive on the light deflection lens 28 (material: polycarbonate, pitch: 140 μm, lens height: 70 μm) having a rounded triangular prism shape formed by extrusion molding in order from the back side. A striped air layer 30 (cross-sectional area height: 2 μm) formed at the boundary between the light deflection lens 28 and the light propagation layer 24, which is formed by laminating and integrating the light propagation layer 24 having an uneven structure via the layer 45. , The cross-sectional area width: 30 μm), the light propagation layer 24 (material: polycarbonate, thickness: 1 mm), and the diffusion base material 26 (material: polycarbonate, thickness: 2 mm). A photomask 40 (material: TiO2, thickness: 5 μm) formed on the viewer side X in order from the light source side through the bonding layer 45 using an acrylic adhesive, Light having an aspheric lens shape formed by a light transmission opening 42 (cross-sectional height: 2 μm, cross-sectional area width: 30 μm), a light-transmitting substrate 34 (material: PET, thickness: 75 μm), and a UV molding method. This is an optical sheet 11 having a size of 37 inches, which is a configuration in which the optical layers 32 of the transmission base unit lens 36 (pitch: 140 μm, lens height: 70 μm) are laminated and integrated. When the liquid crystal display device was moved for 24 hours after being installed in the liquid crystal display device, a problem due to warpage of the optical sheet 11 occurred. According to Comparative Example 3, even when the air layer 30 is provided, if the cross-sectional area of the air layer 30 and the light transmission opening 42 is small, it is impossible to obtain a sufficient cooling effect, and the problem of warpage occurs. confirmed.

Table 1 shows the results of the above comparison and the results of warping for the examples.

The best mode for carrying out the present invention has been described above with reference to the accompanying drawings, but the present invention is not limited to such a configuration. Within the scope of the invented technical idea of the scope of claims, a person skilled in the art can conceive of various changes and modifications, and the technical scope of the present invention also relates to these changes and modifications. It is understood that it belongs to.

(A) Schematic sectional view showing an example of a display device in the present invention (b) Top view showing an example of a linear light source in the present invention The schematic sectional drawing which shows an example which provided the diffusion film in the display apparatus in this invention Schematic sectional view showing an example in which a prism sheet is provided in the display device of the present invention Schematic sectional view showing an example in which a polarizing reflection separating sheet is provided in the display device of the present invention (A) Schematic sectional view showing an example of a display device in the present invention (b) Top view showing an example of a point light source in the present invention Explanatory drawing which shows an example of white LED which is a point light source in this invention Explanatory drawing which shows an example of white LED which is a point light source in this invention Explanatory drawing which shows an example of the combination of monochromatic LED which is a point light source in this invention Explanatory drawing which shows an example of the semiconductor laser which is a point light source in this invention Explanatory drawing which shows the example of the arrangement | positioning method of the point light source or the point light source unit in this invention Explanatory drawing which shows the propagation of the light in the diffusion member in this invention Explanatory drawing which shows the propagation of the light in the diffusion member in this invention Explanatory drawing which shows an example of the light deflection lens in this invention Explanatory drawing which shows an example of the manufacturing method of the diffusion member in this invention The schematic sectional drawing which shows an example of the diffusion member which provided the air layer in the boundary part of the diffusion base material and light propagation layer in this invention Explanatory drawing which shows an example of the manufacturing method of the diffusion member in this invention Explanatory drawing which shows an example of a structure of the diffusion member in this invention Explanatory drawing which shows an example of a structure of the optical sheet in this invention Explanatory drawing which shows an example of a structure of the optical sheet in this invention Explanatory drawing which shows an example of a structure of the optical sheet in this invention Explanatory drawing which shows an example of a structure of the optical sheet in this invention The top view which shows an example of the passage of the air in the opening part for light transmission in this invention Explanatory drawing which shows the way of the air in the opening part for light transmission in this invention Explanatory drawing which shows an example of a structure of the optical sheet in this invention Explanatory drawing which shows an example of a structure of the optical sheet in this invention Explanatory drawing which shows an example of a structure of the optical sheet in this invention Explanatory drawing which shows an example of a structure of the optical sheet in this invention Explanatory drawing which shows an example of a structure of the optical sheet in this invention Explanatory drawing which shows an example of a structure of the optical sheet in this invention Explanatory drawing which shows an example of a structure of the optical sheet in this invention Schematic sectional view showing a display device and a backlight unit in the prior art Schematic sectional view showing a display device and a backlight unit in the prior art Schematic sectional view showing a display device and a backlight unit in the prior art

Explanation of symbols

X ... Viewer side, P1, P2, P3, P4 ... Arrangement position of point light source or point light source unit, L ...
M ... light, A ... air flow, 1 ... light source, 1a ... linear light source, 1b ... point light source, 3 ... reflector, 5 ... display device, 7 ... diffuser film, 8 ... prism sheet, 9 ... polarized light separation / reflection Sheet, 11 ... Optical sheet, 13 ... Back light unit, 14 ... Lens trough, 15 ... Liquid crystal layer, 16 ... Opening part, 17 ... Polarizing plate, 19 ... Driving device for liquid crystal, 21 ... Display part, 25 ... Diffusing member , 26 ... diffusion substrate, 27 ... light propagation layer, 28 ... light deflection lens, 28a ... first apex, 28b ... first inclined surface, 30 ... air layer, 32 ... optical layer, 33 ... translucent substrate, 34 ... Light transmissive substrate, 36 ... Unit lens for light transmissive substrate, 40 ... Light mask, 42 ... Light transmitting opening, 44 ... Fixed element, 45 ... Bonding layer, 46 ... White LED, 47 ... LED substrate, 48 ... Red LED light emitting element, 49 ... Green LED light emitting element, 50 ... Blue LED Optical element, 51 ... phosphor, 52 ... point light source unit, 53 ... LED lens, 54 ... red LED, 55 ... green LED, 56 ... blue LED, 57 ... red semiconductor laser, 58 ... green semiconductor laser, 59 ... blue Semiconductor laser, 60 ... optical fiber, 61 ... semiconductor laser lens, 70 ... extruder, 71 ... hopper, 72 ... screw, 73 ... T die, 74 ... roll mold, 75 ... nip roll, 76 ... injection molding machine, 77 ... Nozzle, 78 ... Plasticizing device, 79 ... Mold, 80 ... Base sheet, 81 ... Clamping device, 82 ... Drive mechanism, 83 ... Projection mechanism

Claims (9)

A light source;
In a backlight unit comprising an optical sheet that supplies light from the light source to a liquid crystal display device,
The optical sheet has at least a light diffusion layer and an optical layer,
A plurality of air layers between the light diffusion layer and the optical layer or between the light diffusion layer and the optical layer, or at least one of the light diffusion layers, or both. An optical sheet comprising: A light source;
In a backlight unit comprising an optical sheet that supplies light from the light source to a liquid crystal display device,
The optical sheet is
Consisting of a diffusing member and an optical layer,
The optical layer is
A photomask arranged in a plurality of stripes on the non-incident surface of the diffusing member;
A light transmission portion disposed between two adjacent optical masks;
On the light mask and the light transmission part, a lens part in which a plurality of unit convex cylindrical lenses are arranged in parallel on the display side,
A surface opposite to the lens portion, and a non-lens surface on which light transmitted by the light transmission portion is incident,
The plurality of unit convex cylindrical lenses correspond to each of the light transmitting portions on a 1: 1 basis, and a perpendicular line from the apex of the corresponding unit convex cylindrical lens to the non-lens surface of the cylindrical lens is the light transmitting portion. Part
And a lenticular sheet arranged in a stripe shape along the longitudinal direction of each unit of the optical mask,
The diffusion member is
A plurality of light deflection elements are provided on the surface of the diffusing member opposite to the observer, and a striped air layer is formed in the diffusing member,
The longitudinal direction is a horizontal direction;
Both ends in the longitudinal direction of each light transmission part and both ends of each air layer are open in the horizontal direction,
And the pressure loss ΔP of the air flowing in the light transmitting part and the air layer is 0 (Pa) <ΔP <2.2 × 10 ² (Pa)
And
The optical sheet is characterized in that a horizontal dimension is larger than a vertical dimension. A light source;
In a backlight unit comprising an optical sheet for supplying light from the light source to a liquid crystal display device,
The optical sheet is
Consisting of a diffusing member and an optical layer,
The optical layer is
A plurality of fixing elements disposed on the non-incident surface of the diffusing member;
The light transmission part disposed between the adjacent fixing elements;
On the fixed element and the light transmission part, a lens part in which a plurality of the unit convex cylindrical lenses are arranged in parallel in a stripe shape on the display side;
A surface opposite to the lens unit, and a non-lens surface on which light transmitted by the light transmission unit is incident,
The diffusion member is
A plurality of light deflection elements are provided on the surface of the diffusing member opposite to the observer, and a striped air layer is formed in the diffusing member,
Both ends of each light transmission part and both ends of each air layer are open in the horizontal direction,
And the pressure loss ΔP of the air flowing in the light transmitting part and the air layer is 0 (Pa) <ΔP <2.2 × 10 ² (Pa)
And
The optical sheet is characterized in that a horizontal dimension is larger than a vertical dimension. A light source;
In a backlight unit comprising an optical sheet for supplying light from the light source to a liquid crystal display device,
The optical sheet is
Consisting of a diffusing member and an optical layer,
The optical layer is
A plurality of fixing elements disposed on the non-incident surface of the diffusing member;
The light transmission part disposed between the adjacent fixing elements;
On the fixed element and the light transmission part, a lens part in which a plurality of the unit convex cylindrical lenses are arranged in parallel in a stripe shape on the display side;
A surface opposite to the lens unit, and a non-lens surface on which light transmitted by the light transmission unit is incident,
The diffusion member is
A plurality of light deflection elements are provided on the surface of the diffusing member opposite to the observer, and a striped air layer is formed in the diffusing member,
Both ends of each light transmission part and both ends of each air layer are open in the vertical direction,
And the pressure loss ΔP of the air flowing in the light transmitting part and the air layer is 0 (Pa) <ΔP <2.2 × 10 ² (Pa)
And
The optical sheet is characterized in that a horizontal dimension is larger than a vertical dimension. A light source;
In a backlight unit comprising an optical sheet that supplies light from the light source to a liquid crystal display device,
The optical sheet is
Consisting of a diffusing member and an optical layer,
The optical layer is
A photomask arranged in a plurality of stripes on the non-incident surface of the diffusing member;
A light transmission portion disposed between two adjacent optical masks;
On the light mask and the light transmission part, a lens part in which a plurality of unit convex cylindrical lenses are arranged in parallel on the display side,
A surface opposite to the lens portion, and a non-lens surface on which light transmitted by the light transmission portion is incident,
The plurality of unit convex cylindrical lenses correspond to each of the light transmitting portions on a 1: 1 basis, and a perpendicular line from the apex of the corresponding unit convex cylindrical lens to the non-lens surface of the cylindrical lens is the light transmitting portion. Part
And a lenticular sheet arranged in a stripe shape along the longitudinal direction of each unit of the optical mask,
The diffusion member is
A striped air layer is formed in the diffusion member having a plurality of light deflection elements on the surface of the diffusion member opposite to the observer,
The longitudinal direction is a horizontal direction;
Both ends in the longitudinal direction of each light transmission part and both ends of each air layer are open in the horizontal direction,
The diffusion member is
A plurality of light deflection elements are provided on the surface of the diffusing member opposite to the observer, and a striped air layer is formed in the diffusing member,
Both ends of each light transmission part and both ends of each air layer are open in the horizontal direction,
And the pressure loss ΔP of the air flowing in the light transmission part, the air layer, and the diffusion member is 0 (Pa) <ΔP <4.4 × 10 ² (Pa).
And
The optical sheet is characterized in that a horizontal dimension is larger than a vertical dimension. 6. A display device comprising: the backlight unit according to claim 1; and an image display unit disposed thereon. A light source;
A cooling method for a backlight unit comprising an optical sheet for supplying light from the light source to a liquid crystal display device,
The optical sheet is
Consisting of a diffusing member and an optical layer,
The optical layer is
A photomask arranged in a plurality of stripes on the non-incident surface of the diffusing member;
A light transmission portion disposed between two adjacent optical masks;
On the light mask and the light transmission part, a lens part in which a plurality of unit convex cylindrical lenses are arranged in parallel on the display side,
A surface opposite to the lens portion, and a non-lens surface on which light transmitted by the light transmission portion is incident,
The plurality of unit convex cylindrical lenses correspond to each of the light transmitting portions on a 1: 1 basis, and a perpendicular line from the apex of the corresponding unit convex cylindrical lens to the non-lens surface of the cylindrical lens is the light transmitting portion. Part
And a lenticular sheet arranged in a stripe shape along the longitudinal direction of each unit of the optical mask,
The diffusion member is
A plurality of light deflection elements are provided on the surface of the diffusing member opposite to the observer, and a striped air layer is formed in the diffusing member,
The longitudinal direction is a horizontal direction;
The both ends of the light transmitting portions in the longitudinal direction and both ends of the air layers are opened in the horizontal direction so that air enters and exits the light transmitting portions and the air layers, and the optical sheet. When the backlight is heated by the light emitted from the light source, the pressure loss ΔP is 0 (Pa) <ΔP <2.2 × 10 ² (Pa). In the cooling method, the backlight unit is cooled by air flowing in the light transmitting portion and the air layer in the horizontal direction. A light source;
A cooling method for a backlight unit comprising an optical sheet for supplying light from the light source to a liquid crystal display device,
The optical sheet is
Consisting of a diffusing member and an optical layer,
The optical layer is
A plurality of fixing elements disposed on the non-incident surface of the diffusing member;
The light transmission part disposed between the adjacent fixing elements;
On the fixed element and the light transmission part, a lens part in which a plurality of the unit convex cylindrical lenses are arranged in parallel in a stripe shape on the display side;
A surface opposite to the lens unit, and a non-lens surface on which light transmitted by the light transmission unit is incident,
The diffusion member is
A plurality of light deflection elements are provided on the surface of the diffusing member opposite to the observer, and a striped air layer is formed in the diffusing member,
By opening both ends of each light transmitting portion and both ends of each air layer in the horizontal direction, air enters and leaves the light transmitting portion and the air layer, and the dimensions of the optical sheet are When the horizontal direction is made larger than the vertical direction and the backlight generates heat due to light emitted from the light source, the air has a pressure loss ΔP of 0 (Pa) <ΔP <2.2 × 10 ² (Pa). A cooling method in which the backlight unit is cooled by flowing in the light transmitting portion and the air layer in a horizontal direction. A light source;
A cooling method for a backlight unit comprising an optical sheet for supplying light from the light source to a liquid crystal display device,
The optical sheet is
Consisting of a diffusing member and an optical layer,
The optical layer is
A plurality of fixing elements disposed on the non-incident surface of the diffusing member;
The light transmission part disposed between the adjacent fixing elements;
On the fixed element and the light transmission part, a lens part in which a plurality of the unit convex cylindrical lenses are arranged in parallel in a stripe shape on the display side;
A surface opposite to the lens unit, and a non-lens surface on which light transmitted by the light transmission unit is incident,
The diffusing member has a plurality of light deflection elements on the surface of the diffusing member opposite to the observer, and a striped air layer is formed in the diffusing member,
By opening both ends of each light transmitting portion and both ends of each air layer in the vertical direction, air enters and leaves the light transmitting portion and the air layer, and the dimensions of the optical sheet are When the horizontal direction is made larger than the vertical direction and the backlight generates heat due to the light emitted from the light source, the air has a pressure loss ΔP of 0 (Pa) <ΔP <2.2 × 10 ² (Pa). A cooling method in which the backlight unit is cooled by flowing from the lower direction to the upper direction in the light transmission part and the air layer.