JP2010102903A - Direct backlight apparatus and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a direct backlight apparatus capable of enhancing the efficiency of energy and lowering unevenness in brightness, while allowing ease of assembly. <P>SOLUTION: The direct backlight apparatus includes a fluorescent lamp, a reflector, and a light diffuser plate. A filament part of the fluorescent lamp includes an emitter and a preheating circuit for preheating the emitter. The fluorescent tube includes a straight portion (a) and a portion (b) which is not parallel to it. In a surface region X of light incidence surface and light outgoing surface, with the external dimension of the portion (a) being projected vertically to the light incidence surface, a light control unit (A), which is almost parallel to the straight portion, is provided for controlling light volume in normal direction. The transmissivity of the region X in normal direction is lower than that of the region X at a middle position by 1% or more. In the light outgoing surface including the region where the external dimension of the portion (b) is vertically projected to the light diffuser plate, a light control unit (B) is provided which extends almost vertically to the straight portion for controlling the volume of light outgoing along the normal direction. The light control unit (A) has a heat transfer function and the light control unit (B) has a heat diffusion function. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a direct-type backlight device and a liquid crystal display device, and more particularly to a direct-type backlight device and a liquid crystal display device that can increase energy efficiency, reduce luminance unevenness, and extend the life. About.

  Conventionally, as a backlight device for a liquid crystal display device, for example, a plurality of linear light sources arranged substantially parallel to each other, a reflecting plate that reflects light from these linear light sources on its surface, and a linear shape A light source that includes a light diffusing plate in which direct light from a light source and reflected light from the surface of a reflecting plate are incident from a light incident surface and is emitted from a light emitting surface is widely used. As the linear light source, a cold cathode tube (CCFL) having a small outer diameter (outer diameter of less than 4 mm) is usually used from the viewpoint that the backlight itself can be thinned. However, in recent years, since the energy efficiency is higher than that of CCFL, a direct type backlight device using a hot cathode tube lamp (HCFL) having a larger outer diameter than CCFL as a linear light source has been developed. .

  However, in the direct type backlight device using the HCFL, the outer diameter of the linear light source is larger than that of the conventional type. Therefore, when the direct type backlight device having the same thickness as the conventional type is created, the distance between the HCFL and the light diffusion plate is reduced. Therefore, the brightness of the light exit surface of the light diffusing plate is higher at the location where the HCFL is projected than at other locations, resulting in uneven brightness on the light emitting surface. Therefore, for example, in Patent Document 1, in a direct type backlight device, a light suppression unit having a thickness larger than that of other portions is provided at a position where a linear light source (for example, HCFL) is projected on a light incident surface to emit light. A technique for reducing the luminance unevenness of the surface is disclosed.

  By the way, when a cathode ray tube is used in a direct type backlight device, in order to reduce the number of parts and facilitate assembly, and to reduce the heat generation amount of the entire backlight by reducing the number of electrodes that generate a large amount of heat, more energy efficiency is achieved. For the purpose of improvement, etc., it is known to use a cathode tube having a shape in which a plurality of straight tubular linear light sources are combined, such as U-shaped and N-shaped, by connecting straight portions with bent portions. It has been. Even when this is used in the above HCFL, effects such as ease of assembly and improvement in energy efficiency can be obtained, but luminance unevenness based on the fact that the luminous body density of the bent portion is higher than that of the straight portion. There is a problem that a large amount of is generated.

JP 2007-95484 A

  An object of the present invention is to provide a backlight device that can increase energy efficiency, reduce luminance unevenness, and can be easily assembled, and a liquid crystal display device using the backlight device.

  The present inventors have intensively studied in view of the above problems, and as a result, projected the area of the linear part of the fluorescent lamp perpendicular to the light diffusion plate and the non-parallel part of the fluorescent lamp projected onto the light diffusion plate. It has been found that by providing light control units having different functions in each of the areas, it is possible to reduce luminance unevenness and ease of assembly, thereby completing the present invention.

According to the present invention, a fluorescent lamp, a reflecting plate that reflects light from the fluorescent lamp on its surface, direct light from the fluorescent lamp and reflected light from the surface of the reflecting plate are incident from a light incident surface. A direct-type backlight device comprising a light diffusing plate that exits from the light exit surface,
The fluorescent lamp comprises a fluorescent tube and a filament portion provided at at least one end of the fluorescent tube,
The filament portion includes a filament and an emitter provided on an outer peripheral portion of the filament,
The direct type backlight device further includes a preheating circuit for preheating the emitter so that the surface temperature thereof is always maintained at 700 to 950 ° C.,
Each of the fluorescent tubes has a straight part (a) and a part (b) non-parallel to the part (a),
In the direct type backlight device, the plurality of portions (a) are arranged substantially in parallel,
On the surface region X in the surface of at least one of the light incident surface and the light emitting surface, in which the outer dimensions of the plurality of portions (a) are projected perpendicularly to the light incident surface, the normal line of the light diffusion plate A light control part (A) extending in a direction substantially parallel to the part (a) for controlling the amount of light emitted along the direction;
In the light diffusing plate, the transmittance in the normal direction of the light diffusing plate in the region X is centered on an intermediate position of the regions X adjacent to each other, and has the same width as the outer diameter of the fluorescent tube, Lower than the transmittance in the direction in which light enters from the center of the fluorescent lamp to the light diffusion plate in the region Y having the same length as the length of the portion of the region X where the light control unit (A) is provided,
The surface region Z _{1 in} the light exit surface, the surface region Z ₂ in the light incident surface, including the region obtained by projecting the outer dimension of the part (b) perpendicularly to the light diffusion plate, and the part of the fluorescent tube ( in at least one region of the surface region T ₂ of the surface of the light diffuser plate side in b), a control amount of light emitted along the normal direction of the light diffuser plate, substantially to the portion (a) A light control section (B) extending in the vertical direction is provided;
The direct-type backlight device is provided in which the light control unit (A) has a heat transfer function and the light control unit (B) has a heat diffusion function.

  According to the invention, there is provided a liquid crystal display device comprising the direct type backlight device and a liquid crystal cell disposed on a light emitting side of the direct type backlight device, wherein the liquid crystal cell is in a VA mode or an IPS mode. Is provided.

  The direct type backlight device of the present invention can increase energy efficiency, reduce luminance unevenness, and can be easily assembled as a backlight device, has high energy efficiency, low luminance unevenness, and easy assembly. An easy liquid crystal display device can be provided.

Preferred embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a perspective view schematically showing a direct type backlight device 100 according to a preferred embodiment of the present invention, and FIG. 2 is a cross-sectional view of the device 100 shown in FIG.

  As shown in FIGS. 1 and 2, the direct type backlight device 100 according to the present embodiment includes a plurality of fluorescent lamps 102, a reflecting plate 101 that reflects light emitted from the fluorescent lamps 102 at a surface 101A, and a fluorescent lamp. A light diffusing plate 131 that diffuses and irradiates direct light from the lamp 102 and reflected light from the reflecting plate 101, a ballast 140 for causing the fluorescent lamp 102 to emit light, and a support pin 2300 that supports the light diffusing plate 131 (FIG. 1). (Not shown).

(Fluorescent lamp)
The fluorescent lamp 102 is preferably a hot cathode tube lamp (HCFL). With such a configuration, a direct-type backlight device with high energy efficiency can be obtained. The fluorescent lamp 102 preferably has a luminous efficiency of 60 (lm / W) or higher. By setting the luminous efficiency within this range and the distance between the centers of the linear portions of the adjacent fluorescent lamps 102 within a preferred range described later, the number of fluorescent lamps 102 used can be reduced. Power consumption can be reduced and the assembly of the device can be facilitated.

  FIG. 3 is a top view schematically showing the configuration of the fluorescent lamp and the ballast. As shown in FIG. 3, the fluorescent lamp 102 includes a fluorescent tube 110 that is a U-shaped cylindrical glass tube, and filament portions (electrodes) 120 provided at both ends of the fluorescent tube 110. The fluorescent tube 110 has a straight portion 110S as a straight portion (a), and also has a bent portion 110C as a portion (b) non-parallel to the portion (a) that connects the ends thereof. ing. The fluorescent tube 110 has a light transmittance of the glass tube at the straight portion 110S (when a light transmission suppressing portion such as printing is provided on the light emitting side of the glass tube, both the glass tube and the light transmission suppressing portion are provided. The light transmittance of the member to be included is set to “light transmittance of glass tube”) is preferably 80% or more, and more preferably 85% or more. By setting the light transmittance of the glass tube at the straight portion 110S within the preferable range, there is an advantage that light from the lamp can be efficiently extracted. The light transmittance of the fluorescent tube 110 can be measured by a turbidimeter NDH2000 manufactured by Nippon Denshoku Industries Co., Ltd. with the same glass material in a plate shape. The length of the straight portion 110S of the fluorescent tube 110 is preferably 700 mm or more. When a fluorescent tube having a straight portion length of 700 mm is used, the deflection is 2 mm when both ends of the straight portion are supported. It is preferable that no more occur.

In the present invention, the straight portion (a) of the fluorescent tube is a straight portion extending substantially in parallel (within ± 5 °), which occupies 50% or more of the total length among all the fluorescent tubes in the backlight device. be able to. Or it can be set as the part substantially parallel to the longitudinal direction of a backlight apparatus. When the fluorescent tube 110 shown in FIG. 3, the boundary between the straight portion 110S (part (a)) and the bent portion 110C (part (b)) includes a vertical through 110S streets, points 116P ₁ shown in FIG. 4 Can be separated by plane. Here, the point 116P ₁ is an inner line 116A of the straight portions 110S, and the intersection of the tangent line 116B of the inner curvature of the fluorescent tube 110, the angle theta ₁₁₀ is a line 116A and 116B are 5 °.

  In the present embodiment, the fluorescent tube 110 includes a glass tube having a circular cross section cut by a plane perpendicular to the length direction of the fluorescent tube, and a fluorescent layer provided on the inner surface of the glass tube. The fluorescent layer can be formed by coating using a known fluorescent material.

  The cross section of the fluorescent tube 110 cut by a plane perpendicular to the length direction of the fluorescent tube is not limited to the circular shape of the present embodiment. For example, from the viewpoint of reducing luminance unevenness, a part of the circle is flattened. It can also be a flat circular shape such as a shape or an elliptical shape. The outer diameter (tube diameter) of the fluorescent tube is preferably 4.0 to 25.5 mm, preferably 6.0 to 20.0 mm, and more preferably 8 mm to 15.5 mm. By making the outer diameter within the preferred range, the backlight device itself can be thinned, and the light diffusing plate due to the vicinity of the filament portion 120 (tube wall temperature) becoming high (eg, over 150 ° C.). There is an advantage that thermal degradation of 131 can be suppressed and sufficient luminance can be achieved. The tube thickness (thickness) of the glass tube of the fluorescent tube 110 is preferably 0.3 to 1.5 mm, more preferably 0.4 to 1.0 mm, and 0.5 mm to 0.7 mm. More preferably. By setting the tube thickness within the preferable range, it is possible to prevent the vicinity of both end portions of the fluorescent tube 110 from becoming dark and to reduce unevenness in luminance on the light emitting surface.

  The filament portion 120 is a member that receives an electric current from the ballast 140 and emits electrons from one filament portion 120 toward the other filament portion 120. The preheating current supplied to the filament part 120 is preferably 100 to 1000 mA. By setting the preheating current within the above preferred range, there is an advantage that the consumption of the emitter applied to the filament can be suppressed and the electrode life can be extended.

The filament portion 120 includes a filament 122 made of tungsten or the like, and an emitter 124 provided on the outer peripheral portion of the filament 122 by coating or the like.
The emitter 124 is a member for facilitating electron emission from the filament 122. As a material constituting the emitter 124, for example, an alkaline earth metal oxide can be used. Specifically, calcium oxide (CaO), magnesium oxide (MgO), strontium oxide (SrO), and barium oxide ( BaO) and the like.

  The filament section 120 is preheated at all times, that is, when an image is displayed on the liquid crystal display device. At this time, the surface temperature of the emitter 124 is always maintained at 700 to 950 ° C. The backlight fluorescent lamp responds to high-speed flashing (flashing for 0.1 seconds or less) during dimming or blinking mode, and sometimes turns off, but the filament 120 is preheated even in such a case. Yes. By performing such preheating, the life of the fluorescent lamp 102 can be extended. Here, when the filament portion 120 is always preheated, for example, when the outer diameter of the glass tube is 8.0 mm, the filament portion is about 140 ° C., and at the intermediate position of the straight portion 110S of the fluorescent tube 110, 50-55 ° C. Moreover, when the outer diameter of a glass tube is 15.5 mm, it turns out that a filament part will be about 120 degreeC and it will be about 50-55 degreeC in the intermediate position of the linear part 110S. For this reason, local heating is applied to the light diffusing plate, but the problem due to this heating is solved by devising the configuration of the light diffusing plate and releasing heat to another area of the light diffusing plate as described later. Is possible. In the case where the preheating is not performed, when the tube diameter is 8.0 mm, the filament portion is about 100 to 110 ° C., and is about 50 to 55 ° C. at the intermediate position of the linear portion 110S of the fluorescent tube. Further, when the tube diameter is 15.5 mm, the filament portion is about 80 ° C., and is about 50 to 55 ° C. at the intermediate position of the linear portion 110S of the fluorescent tube.

  As a configuration for achieving preheating of the filament part, the direct type backlight device of the present invention includes a circuit for supplying a current for preheating as part of a circuit for causing the fluorescent lamp to emit light.

  Further, in the region where the bent portion of the fluorescent lamp is projected onto the light diffusing plate, the heat source in the vicinity of the light diffusing plate is increased, and therefore, the temperature may be 2 to 10 ° C. higher than other regions of the light diffusing plate. This heating problem can be solved by devising the configuration of the light diffusing plate and releasing heat to another part of the backlight as described later.

  The number of fluorescent lamps 102 used is not limited. For example, when the direct type backlight device of the present invention is used for a 32-inch liquid crystal display device, the number of fluorescent lamps can be set to 1 to 16, for example, depending on the target luminance and the target power consumption. Can be determined as appropriate.

Further, the shape of the fluorescent lamp 102 is not limited. For example, in addition to the U-shape, a single fluorescent lamp has an N-shape with three straight portions and two bent portions, and a W-shape with four straight portions and three bent portions. Etc. can also be used. Specifically, a fluorescent lamp having the following shape can be used.
The two straight portions that extend in parallel with each other as the portion (a) and each include the end of the fluorescent tube, and one ends of the two straight portions as the portion (b) A fluorescent lamp having a U-shaped fluorescent tube including a bent portion to be connected.
The two straight portions (a) and (b), which extend in parallel with each other as the portion (a), each including the end of the fluorescent tube, and the straight portions (b) and (b) One part (c) extending in parallel and parallel to the straight part; and a bent part connecting the one end of the straight part (b) and one end of the part (c) as the part (b) (D) and a fluorescent lamp having an N-shaped fluorescent tube including a bent portion (e) that connects one end of the straight portion (b) and the other end of the portion (c).
Two linear portions (f) and (g) extending in parallel with each other as the portion (a); and one end and a straight portion (g) of the straight portion (f) as the portion (b) A square fluorescent tube that includes a portion (H) that connects one end of the straight portion (F) and a portion (R) that connects the other end of the straight portion (F) and the other end of the straight portion (G). Fluorescent lamp.
The two parts (n) and (le), which extend in parallel with each other as the part (b), each including the end of the fluorescent tube; and the two parts as the part (a) A fluorescent lamp having a U-shaped fluorescent tube including one portion (W) that connects one ends of straight portions.

  In the present embodiment, the straight portions of the plurality of fluorescent lamps 102 are arranged substantially parallel to each other. The average distance between the central axes of the straight portions 110S of other adjacent fluorescent lamps 102 is substantially constant. Note that “substantially parallel” means within a range of ± 5 degrees from a truly parallel state. However, the linear portions of the plurality of fluorescent lamps do not have to be arranged in parallel. In addition, the average distance between the central axes of the linear portions of the adjacent fluorescent lamps may be random, and has regularity that increases or decreases continuously or stepwise toward a specific location. It may be allowed. Here, the specific location is, for example, a central location including a line connecting one long side of a rectangular light diffusing plate or the central locations of opposing short sides.

  The average distance between the central axes of the linear portions 110S of the adjacent fluorescent lamps 102 can be 60 mm to 300 mm, and preferably 70 mm to 250 mm. By setting the average distance in the above range, it is possible to reduce power consumption in the direct type backlight device, to easily assemble the device, and to suppress luminance unevenness of the light emitting surface.

  The average distance b (mm) (the distance corresponding to the length of the arrow b in FIG. 2) between the central axis 116G of the linear portion 110S of the fluorescent lamp 102 and the light incident surface 131B of the light diffusion plate 131 is a direct type back. The thickness may be designed in consideration of the thickness of the light device, the diameter of the fluorescent lamp, and the luminance uniformity, but it may be 2 mm to 35 mm, and preferably 3 mm to 30 mm. By setting the average distance b in the above range, it is possible to reduce luminance unevenness and to prevent a decrease in the luminous efficiency of the lamp, and to reduce the thickness of the direct type backlight device. In the present embodiment, the plurality of fluorescent lamps 102 are arranged such that the average distance b with respect to the light incident surface 131B is substantially constant for all the fluorescent lamps. Note that “substantially constant” means that when the average distance b is obtained for each lamp, the maximum value of the average distance b / the minimum value of the average distance b ≦ 1.3 for all the average distances b. However, a plurality of fluorescent lamps may be arranged so that some fluorescent lamps are closer to the light incident surface 131B than other fluorescent lamps. For example, it may be random or may have regularity that becomes larger or smaller as it goes to a specific location. Here, the specific location is, for example, a central location including a long side of a rectangular light diffusing plate or a line connecting the central locations of opposing short sides.

  The ballast 140 is a member that rectifies an alternating current from a commercial power source and supplies a predetermined current to the filament unit 120 to promote emission of electrons from the filament unit 120. The ballast 140 of this embodiment is a ballast choke inverter (not shown) that enables instantaneous light emission.

  In the apparatus of the present invention, when a plurality of fluorescent lamps are arranged, the linear portions (a) are arranged in parallel. It is preferable that the distance from each fluorescent lamp to the light diffusion plate and the distance from each fluorescent lamp to the reflection plate are equal. Further, as in the embodiment shown in FIG. 6, the number of bent portions in one fluorescent tube is an odd number, the linear portion of the fluorescent tube is substantially parallel to the long side of the backlight device, and the electrodes are the same as those of the backlight device. By setting it in a state where either one of the short sides is aligned, it is possible to facilitate the manufacture of the device and to achieve downsizing of the device by simplifying the wiring. On the other hand, when the number of bent portions in one fluorescent tube is an odd number, the linear portion of the fluorescent tube is substantially parallel to the long side of the backlight device, and the fluorescent tubes are arranged so that the electrodes are alternated, It is preferable from the viewpoint that heat dissipation is easier. 25, the number of bent portions in one fluorescent tube is an odd number, the linear portion of the fluorescent tube is substantially parallel to the short side of the backlight device, and the electrodes are the same as those of the backlight device. If the long side is aligned, the number of fluorescent lamps will increase, but the backlight device should be arranged so that the side with the electrodes is on the upper side when using the display device. It is preferable from the viewpoint that heat radiation to the outside of the apparatus becomes easier.

(Support pin)
The support pin 2300 is a pin-shaped member that is disposed between the reflection plate 101 and the light diffusion plate 131, that is, on the reflection plate 101, and supports the light diffusion plate 131 so as not to bend. A more detailed example of the arrangement of the support pins 2300 is shown in FIG. In FIG. 6, in this embodiment, two support pins 2330A and 2330B are arranged in the vicinity of a certain filament portion 120A. A more detailed example of one support pin 2300 is shown in FIG. In the present embodiment, the support pin 2300 is a contact surface in which a hemisphere is further placed on a truncated cone shape whose upper diameter is slightly smaller than the bottom diameter 2332. However, the present invention is not limited to this, and other shapes such as a part of a sphere, an elliptical rotating body, a part thereof, and a polyhedron can be used. Further, the height 2331 of the support pin 2300 can be appropriately adjusted according to a desired distance between the reflection plate and the light diffusion plate.

  Here, the distance between the support pin 2330A closest to the emitter and the emitter constituting the filament portion 120 is preferably within 250 mm, and more preferably within 200 mm. The reason will be described below. Here, by always preheating the emitter, the surface temperature of the glass tube near the filament portion of the fluorescent tube becomes 100 ° C. or higher. For this reason, the light incident surface of the light diffusing plate in the vicinity of the filament portion is heated, causing deformation such as a convexity toward the fluorescent tube, and uneven brightness may occur. Therefore, by disposing the support pins within the preferable range, local deformation in the vicinity of the filament portion can be suppressed and occurrence of luminance unevenness can be suppressed.

  Further, when any one of the support pins in the apparatus is selected, the distance between this support pin and another support pin closest to this support pin is preferably within 200 mm, and within 150 mm. More preferably. As described above, the light incident surface of the light diffusing plate in the vicinity of the filament portion is heated, causing deformation such as a convexity toward the fluorescent tube, and uneven brightness may occur. For this reason, by making the distance between the support pins in the above-mentioned preferable range in the vicinity of the filament portion, local deformation in the vicinity of the filament portion can be suppressed, and the occurrence of luminance unevenness can be further suppressed.

  Note that the distance between the support pin 2300 and the emitter refers to the position of the center of gravity of the contact surface of the tip of the support pin that contacts the light incident surface of the light diffusion plate (in the example shown in FIG. 23, the center of the circle 2333) and the emitter. It is the shortest distance from the position projected perpendicularly to the light incident surface. The distance between the support pins is the distance between the gravity center positions of the contact surfaces at the tips of the support pins. In the present embodiment shown in FIG. 6, the direct type backlight device is configured by including 19 support pins 2300, but the number of support pins may be more or less. In addition, the support pin may or may not have the function of a fluorescent tube holder that prevents the fluorescent tube from being bent.

  Furthermore, the distance between the center of gravity of the bent portion and the pin closest to the bent portion is preferably within 250 mm, and more preferably within 200 mm. The reason will be described below. Here, the surface temperature of the light diffusing plate becomes 100 ° C. or higher due to an increase in heat sources in the vicinity of the light diffusing plate at the bent portion. For this reason, the light incident surface of the light diffusing plate in the vicinity of the bent portion is heated, causing deformation such as a convexity toward the fluorescent tube, and uneven brightness may occur. Therefore, by arranging the support pins within the above preferred range, local deformation in the vicinity of the bent portion can be suppressed and occurrence of luminance unevenness can be suppressed.

  The distance between the center of gravity of the bent portion and the pin closest to the bent portion is the position of the center of gravity of the contact surface of the tip of the support pin that contacts the light incident surface of the light diffusing plate 131 and the center of gravity of the bent portion perpendicular to the light incident surface. Is the shortest distance from the projected position.

(a reflector)
The shape of the reflecting plate 101 is usually a flat plate, but from the viewpoint of further reducing the luminance unevenness of the light emitting surface, the reflecting plate 101 protrudes toward the light diffusing plate in a region corresponding to the linear portion of the fluorescent lamp. There may be provided a protruding portion. This protrusion may extend along the longitudinal direction of the plurality of fluorescent lamps. At this time, the protrusion is preferably provided at a substantially intermediate position between the adjacent fluorescent lamps, but may be provided on the back surface of the fluorescent lamp 102. Furthermore, the cross-sectional shape in the short direction of the protrusion is not particularly limited, but isosceles triangle, isosceles trapezoid, circular cut shape, elliptical shape cut by a line segment parallel to the short axis, and elliptical shape is long. Examples include a shape cut along a line segment parallel to the axis, a shape in which downward convex curves are connected so as to be a line object, and a shape in which upward convex curves are connected in line symmetry. The apex portions of these shapes may be pointed or rounded. From the viewpoint of reducing luminance unevenness and the viewpoint of ease of manufacturing, a triangular shape is preferable. Moreover, it is preferable that the cross-sectional shape of the protrusion is line symmetric with respect to a line segment perpendicular to the thickness direction of the light diffusion plate. By setting it as such a structure, the brightness nonuniformity in the light-projection surface of a light diffusing plate can be suppressed. The protrusions may be continuous in a bowl shape or intermittent as a series of pits, but are preferably continuous because the brightness uniformity can be further improved.

  The protrusions may be installed by coating a metal frame with protrusions in white or silver, attaching a white or silver reflective sheet to the metal frame with protrusions, white or silver flat Examples thereof include a method of bending the reflecting sheet and placing it on a flat metal frame, a method of molding a white or silver resin using a mold having a predetermined shape, and the like.

  As a material constituting the reflector 101, a resin colored in white or silver, a metal, or the like can be used, and a resin is preferable from the viewpoint of weight reduction. The color of the reflector 101 is preferably white from the viewpoint of improving the luminance uniformity, but may be a mixture of white and silver in order to balance the luminance and the luminance uniformity highly.

(Light diffusion plate)
The light diffusion plate 131 is a plate material that diffuses and emits the direct light from the fluorescent lamp 102 and the reflected light from the surface of the reflection plate 101. As a material constituting the light diffusing plate 131, glass, a mixture of two or more kinds of resins that are difficult to mix, a material in which a light diffusing agent is dispersed in a transparent resin, and one kind of transparent resin can be used. Among these, a resin is preferable because it is lightweight and easy to mold, and one kind of transparent resin is preferable from the viewpoint that luminance can be easily improved, and adjustment of total light transmittance and haze is easy. From the viewpoint, a transparent resin in which a light diffusing agent is dispersed is preferable.

  The transparent resin is a resin having a total light transmittance of 70% or more measured with a 2 mm-thick plate smooth on both sides based on JIS K7361-1, for example, polyethylene, propylene-ethylene copolymer, Polypropylene, polystyrene, copolymer of aromatic vinyl monomer and (meth) acrylic acid alkyl ester having a lower alkyl group, polyethylene terephthalate, terephthalic acid-ethylene glycol-cyclohexanedimethanol copolymer, polycarbonate, acrylic resin, And a resin having an alicyclic structure. In addition, (meth) acrylic acid is acrylic acid and methacrylic acid.

  The thickness of the light diffusing plate 131 is preferably 0.4 to 5.0 mm, and more preferably 0.8 to 4.0 mm. By setting the thickness of the light diffusing plate within the above preferable range, it is possible to suppress bending due to its own weight and to facilitate the molding. The distance between the light incident surface 131B of the light diffusing plate 131 and the surface of the reflecting plate 101 is preferably within 100 mm, more preferably within 40 mm, and within 25 mm from the viewpoint of reducing the thickness of the direct type backlight device. Is more preferable.

  The light diffusing plate 131 has a residual stress of preferably 10 MPa or less, more preferably 5 MPa or less, and further preferably 3 MPa or less. Here, the residual stress of the light diffusing plate can be obtained as follows. That is, first, a 100 × 10 mm strip sample is cut out from one light diffusion plate. Next, the surface of the sample (for example, the surface on the gate side when the light diffusion plate is formed by an injection molding machine having a gate in the surface) is polished with sandpaper while being cooled with water. After polishing 1 mm, the strain amount ε is obtained using the following formula (1). In calculating the amount of strain, the thickness t (mm) of the sample is measured by three-point measurement using a dial gauge, the deflection amount δ (mm) after polishing is measured, and the length l (mm) in the longitudinal direction of the sample is measured. To do. The residual stress can be obtained by the following formula (2) using the strain amount ε and the elastic modulus E of the sample.

  As described above, by always preheating the emitter, the vicinity of the filament portion of the light incident side surface of the light diffusion plate is exposed to a high temperature. In addition, by having the bent portion, particularly the vicinity of the bent portion of the light incident side surface of the light diffusing plate is exposed to a high temperature. Here, when the residual stress of the light diffusing plate is large, there may be a difference in the shape change method between the vicinity of the filament part, the vicinity of the bent part, and the intermediate position of the linear part of the fluorescent tube due to heat. In this case, the light diffusing plate may have a wave shape and uneven brightness may occur. For this reason, generation | occurrence | production of the brightness nonuniformity by a shape change etc. can be suppressed by making the residual stress of a light diffusing plate into the said suitable range.

  The light diffusing plate 131 preferably has a difference (Emax−Emin) between the maximum value Emax of the residual stress in the plane and the minimum value Emin of the residual stress in the plane of 10 MPa or less. Is more preferable, and 3 MPa or less is more preferable. As described above, the light incident side surface of the light diffusion plate is exposed to a high temperature. Here, when the difference in residual stress in the plane of the light diffusing plate is large, the light diffusing plate has a wave shape due to different deformation methods depending on the location, and luminance unevenness may occur. For this reason, by making the residual stress difference of the light diffusing plate within the above suitable range, it is possible to suppress the occurrence of luminance unevenness due to a shape change or the like.

  The light control unit preferably further has a function of reflecting and / or refracting infrared rays. In the present embodiment, the concavo-convex structure is used as the incident-side light control unit. However, according to the concavo-convex structure, infrared rays can be refracted.

  As described above, the amount of infrared rays emitted from the vicinity of the filament portion is increased by always preheating the emitter. For this reason, by using the incident side light control unit having the above function, the amount of infrared rays is made uniform in the direct type backlight device, thereby making the temperature distribution of the liquid crystal panel uniform and suppressing display unevenness. . In addition, the measurement of the amount of infrared rays can be obtained by, for example, Fastavert S-2400 manufactured by Soma Optics. Specifically, on the light emitting side of the direct type backlight device, the amount of infrared light having a wavelength of 800 to 900 nm in the normal direction of the main surface of the light diffusing plate can be measured and obtained at each location.

  Here, the amount of infrared rays is made uniform means that the emission intensity at a wavelength showing a peak among infrared rays having a wavelength of 800 to 900 nm is obtained, and the filament part of the fluorescent lamp is projected perpendicularly to the light incident surface. And the emission intensity β at the position where the intermediate position of the filament part on the same side of the adjacent fluorescent lamp is projected perpendicularly to the light incident surface is compared, and β / α ≧ 0.45. Preferably, β / α ≧ 0.50, and more preferably β / α ≧ 0.55.

Next, the configuration of the unevenness provided on the entrance surface and the exit surface of the light diffusion plate will be described.
FIG. 6 is a top view showing a state in which the direct-type backlight device according to the present embodiment has its emission surface placed horizontally upward. The boundary (line corresponding to 110D in FIG. 3) between the straight line part (part (a)) and the bent part (part (b) non-parallel to part (a)) of the fluorescent tube 110 is indicated by a line 610D. In the case of the present embodiment, a rectangular region (surface region Z) surrounded by the side 631W1 and the line 631C in the light incident surface, including a region obtained by projecting the outer dimension of the bent portion perpendicularly to the light incident surface of the light diffusion plate 631. ₂ ), and a region obtained by projecting the outer dimension of the straight line portion perpendicularly to the light incident surface (surface region X: in FIG. 6, the region surrounded by the line indicating the fluorescent tube 110 is shown on the left side of the line 610D. A rectangular region surrounded by the side 631W2 and the line 631C is defined, including the majority of the portion (which coincides with the portion).

  The surface region X will be further described with reference to FIG. 2. The surface region X in the present embodiment is surrounded by lines 116UA1 and 116UA2 obtained by projecting the outer dimension of the axis 116SA of the fluorescent tube straight line portion perpendicularly to the light diffusion plate. The region and the region surrounded by lines 116UB1 and 116UB2 obtained by projecting the outer dimension of the axis 116SB perpendicularly to the light diffusion plate.

  Returning to FIG. 6, in this embodiment, on the surface region X in the region of the sides 631W2 to 631C in the incident surface of the light diffusing plate, the amount of light emitted along the normal direction of the light diffusing plate is expressed as follows. An optical control unit (A) that extends in a direction substantially parallel to the linear portion is provided to be controlled. As a specific configuration of the light control unit (A), an uneven structure having an arithmetic average roughness Ra of 3 to 1000 μm formed on the surface of the light incident surface, or a printed layer provided on the light incident surface It can be. With this configuration, the amount of light emitted from the light diffusing plate along the normal direction can be controlled.

  More specifically, the concavo-convex structure as the light control unit (A) includes a prism strip in which linear lens components such as a cylindrical lens component or a triangular prism extending substantially in parallel with the fluorescent tube portion (a) are arranged. A structure of a concave or convex groove component such as a row can be mentioned. An example of such a prism row will be described with reference to FIG. FIG. 7 is a partial elevation cross-sectional view of the light diffusing plate shown in FIG. 6 when observed from the side 631W2. On the light incident surface 631B of the light diffusing plate, a prism row is formed that has an isosceles triangle cross section and extends in a direction parallel to the direction of the side 631L (that is, substantially parallel to the fluorescent tube portion (a)). Has been. By making the apex angle 662T of this prism different between the surface region X and other regions, the amount of light emitted from the light diffusion plate along the normal direction is not provided with the control unit (A). It can be controlled to be smaller than that of the diffusion plate, and brightness unevenness in the entire light diffusion plate can also be reduced.

  As the concavo-convex structure as the light control unit (A), in addition to the above-described one, other concavo-convex shapes such as a quadrangular pyramid or an indented shape of the quadrangular pyramid, and the prism row as a part of the slope It is also possible to use one having the same direction and angle as those having one.

  On the other hand, it is the same width as the outer diameter of the fluorescent tube and the same length as the portion of the region X where the light control unit (A) is provided (the length of the light control unit (A) as will be described later). In the present invention, the region Y) can be shorter than the length of the region X. In the example of FIG. 2, an area having the same width as the area X is centered on the intersection of the line 116M passing through the midpoint between the fluorescent tube straight portions 116SA and 116SB and perpendicular to the light diffusing plate and the incident surface of the light diffusing plate. This is the region Y in the present invention.

  In the present invention, the transmittance in the normal direction of the light diffusing plate in the region X is the direction in which light enters the light diffusing plate in the region Y from the center of the fluorescent lamp (in the example shown in FIG. 115% direction) and preferably 1% or more lower. Here, “low by 1% or more” means that the difference obtained by subtracting the% value of the light transmittance of the region X from the% value of the light transmittance of the region Y is 1 or more.

On the other hand, in the present embodiment, a rectangular region (surface region) surrounded by the side 631W1 and the line 631C in the light incident surface, including a region obtained by projecting the outer dimension of the bent portion perpendicularly to the light incident surface of the light diffusion plate 631. In Z ₂ ), there is provided a light control section (B) extending in a direction substantially perpendicular to the straight section for controlling the amount of light emitted along the normal direction of the light diffusion plate.

  In the present invention, the light control unit (A) does not necessarily have to be provided on the entire surface of the region X, and only a part thereof, preferably 50% or more may be provided. Specifically, for example, in the example shown in FIG. 6, the light control unit (A) is not provided in the region X in the region surrounded by the lines 610D and 631C, and the light control unit (B) Even in this case, the effect of the present invention can be obtained. On the other hand, the light control unit (B) is an area including the entire surface of the fluorescent tube portion (b) (bending portion 110C in the example shown in FIG. 3) projected perpendicularly to the light diffusion plate. It is preferable to provide it. In addition, in the boundary part between the light control unit (A) and the light control unit (B), there may be a place where neither the light control unit (A) nor (B) is provided. From the viewpoint of reducing luminance unevenness, the width of the portion is preferably 5 mm or less.

This point will be described with reference to FIG. Point of FIG. 5 116P ₃ corresponds to a point when viewed in the axial 116F straight segment 116X of the bent portion 110C in FIG. 3 from the side. Around the position 116P ₄ projected perpendicularly this point 116P ₃ on the light diffusion plate 131, to a position one is reaching straight portions 110S side of the line 110D (boundary of the straight portions 110S and the bent portion 110C), while The region up to the edge of the light diffusing plate can be used as the light control unit (B). For example, the range in which the light control unit (B) extends toward the linear portion 110S is defined as extending the light diffusion unit (B) to the intersection 116P2 between the line that forms the angle θ ₁₁₆ with 116C and the light diffusion plate. , Θ116 can be in the range up to 45 °.

  Furthermore, the light control units (A) and (B) may be overlapped in order to further reduce luminance unevenness. In that case, a structure having both properties is provided in the overlapping region. As an example of the structure having both properties, for example, a region surrounded by lines 1231C and 1231D in Example 5 described later can be given. Other examples include a region 2832 in Example 20 described later and the entire light incident surface in Example 21.

  Regarding the structure of the light control unit (B), a structure satisfying a predetermined function is appropriately selected from the uneven structure similar to that of the light control unit (A) or the printed layer provided on the light incident surface. Can do.

  An example of the light control unit (B) will be further described with reference to FIG. In the region of the lengths 652A and 652B around the position where the light diffusion plate intersects the direction 116C perpendicular to the light diffusion plate through the axis 116F of the bent portion of the fluorescent tube 110 shown in FIG. ) As a triangular prism 663. Here, the triangular prism 663 extends in a direction perpendicular to the prism 662 described in FIG.

  In the present invention, the light control unit (A) has a heat transfer function, and the light control unit (B) has a heat diffusion function.

  Here, the heat transfer function of the light control unit (A) is the temperature of the light incident surface at a position that is the central axis in the extending direction of the control unit and is on the line extending over the entire length of the control unit and closest to the filament. And the difference between the temperature of the light incident surface at the position where the temperature is lowest when the apparatus is driven on the line is the value of the difference when a light diffusion plate (flat plate diffusion plate) without such a light suppressing portion is used. Rather than 0.5 ° C. or higher. Here, “the position at which the temperature is the lowest on a line passing through the filament portion and extending in the entire length direction of the control portion” specifically refers to, for example, the straight portion 110S when a U-shaped fluorescent tube shown in FIG. 3 is used. In the hot cathode tube 2210 having the N-shaped fluorescent tube shown in FIG. 22 on the linear portion axis 2216G, the length of the control portion (A) corresponds to the central portion in the longitudinal direction. This is an intermediate position between the lines 2231C1 and 2231C2 that define the end of the direction. In addition, when the square fluorescent lamp 2890 is arranged and used as shown in FIG. 28, the axis 3092Q1 is arranged on the axis 2892B, and when the square fluorescent lamps 3090S1 to 3090S5 are arranged and used as shown in FIG. The temperature difference between the location closest to the filament and the location farthest from the filament on each of 3091Q10 can be measured as the temperature difference.

  The temperature in the vicinity of the filament part of the fluorescent tube is 120 ° C. to 140 ° C., which is higher than the glass transition temperature (Tg) of the transparent resin constituting the light diffusing plate. Therefore, it is possible to prevent local warpage and yellowing and to suppress increase in luminance unevenness due to them.

  On the other hand, the heat diffusion function of the light control unit (B) is a light diffusion plate (flat plate diffusion plate) without the light control unit (B) where the temperature at the highest temperature when the device is driven in the plane of the control unit. ) Is a function that can be lowered by 0.5 ° C. or more than the temperature in the case of using. For example, when the U-shaped tube 110 (FIG. 3) is used as in the first embodiment, such a position having the highest temperature is on the light diffusion plate corresponding to the midpoint 116P3 of the axis 116F of the bent portion. This corresponds to the position. By diffusing the heat of the light diffusing plate in the vicinity of the bent portion, heat storage can be reduced even slightly, local temperature rise can be prevented, and local display defects of the liquid crystal panel can be eliminated. Furthermore, in the present invention, since the part having the heat transfer function and the part having the heat diffusion function extend perpendicular to each other, it is possible to more efficiently dissipate heat.

In the embodiment described above, the light control section (B), is provided on the surface area Z ₂ of the light incidence plane of the light diffusion plate, the present invention is not limited thereto, the outer dimension of the portion (b) The light control unit is applied to the surface region Z ₂ in the light incident surface including the region vertically projected onto the light diffusing plate, or the surface region T ₂ on the surface on the light diffusing plate side in the portion (b) of the fluorescent tube. (B) can be provided (for example, as shown in Examples 10 and 11, printing is provided on a bent portion of a U-shaped fluorescent tube), or two or more of these can be provided in combination.

  Of the light incident surface and the light exit surface of the light diffusion plate, the surface on which the light control units (A) and (B) are not provided is not particularly limited, but the light control units (A) and (B) Separately, it is possible to provide an uneven structure such as a prism row for adjusting the luminance and luminance unevenness of the emitted light, and a row of lenticular lenses.

(Other preferred requirements)
In the direct type backlight device of the present invention, the outer diameter of the fluorescent lamp, the distance between the fluorescent lamp portions (a) (straight line portions), and the distance from the reflector to the diffuser are within the preferred ranges as described above. In particular, (i) the fluorescent lamp has an outer diameter of 10 to 20 mm, (ii) the interval between the fluorescent lamp portions (a) (straight line portions) is 60 mm or more, and (iii) Backlight with respect to power consumption when the ratio of ((outer diameter of fluorescent lamp) / (distance from reflector to diffuser)) is 0.4 or more and 0.9 or less This is preferable because the ratio of the amount of light emitted from the head becomes particularly high. If the fluorescent lamp is considered as a single unit, the thicker the lamp, the more light emission, and the higher the luminous efficiency (light emission amount / total power consumption including preheating). However, when it is incorporated in a direct type backlight device, the light reflected from the reflecting plate and the diffusing plate is absorbed by the phosphor of the fluorescent lamp. This amount of absorption decreases when the lamp diameter is small, the lamp pitch is large, or the distance between the reflector and the diffuser is large. As the optimum range in which these effects are combined, the total luminous efficiency can be particularly enhanced when the above conditions (i) to (iii) are satisfied.

(Other components)
The direct type backlight device of the present invention can have an optical sheet such as a prism sheet or a diffusion sheet in addition to the above components. These optical sheets can be provided on the light emitting side of the light emitting surface. With these optical sheets, the direction of the light emitted from the light emitting surface can be converted so as to approach the direction parallel to the normal line of the optical sheet.

(Liquid crystal display device)
The liquid crystal display device of the present invention includes the direct type backlight device of the present invention and a liquid crystal cell disposed on the light emission side of the direct type backlight device. The liquid crystal cell is a VA mode or IPS mode cell. Since the direct type backlight device of the present invention is excellent in heat dissipation effect and durability, the liquid crystal display device of the present invention is less likely to cause defects such as display disturbance and physical distortion of the device even when driven for a long time.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. In the following, “part” and “%” related to the quantity ratio of substances represent mass ratios unless otherwise specified.

<Example 1>
A direct type backlight device including a reflector, a fluorescent lamp, and a light diffusing plate was produced.

(1-1: reflector)
A reflective plate (“E6SV”, manufactured by Toray Industries, Inc.) was attached to the inner surface of an aluminum case having an inner length of 1017 mm, a width of 572 mm, and a depth of 25 mm, thereby creating a reflector.

(1-2: Hot cathode tube lamp)
A hot cathode tube lamp having a fluorescent tube 110 made of a U-shaped soda lime glass and a filament portion 120 having a shape schematically shown in FIG. 3 was prepared. The fluorescent tube 110 had an outer diameter of about 15.5 mm, a glass thickness of 0.7 mm, and a glass transmittance of 90%. The cross section of the fluorescent tube 110 in a plane perpendicular to the axes 116G and 116F was circular. The tube length of the straight portion 110S on the straight line side from the dotted line 110D of the fluorescent tube 110 is 1020 mm, and these are connected by the bent portion 110C so that the interval 116G is 90 mm. The bent portion has a straight portion 116X having a center line 116F having a length of about 60 mm and an angle of 90 ° with the straight portion, and both ends of the portion 116X are via portions bent at a curvature radius of 13 mm. It was connected with the straight part 110S. At both ends of the fluorescent tube 110, electrodes 120 were disposed on a triple-coiled tungsten filament 122 by applying and adhering an emitter (electron emitting material) 124 containing BaO, SrO, and CaO at a ratio of 3: 1: 1. . Further, a three-wavelength light emitting phosphor is formed on the inner wall surface of the fluorescent tube 110, and mercury and 0.5 kPa of argon are sealed in the fluorescent tube 110.

(1-3: Light diffusing plate)
A mold part of a predetermined shape is placed in an injection molding machine (clamping force 9,810 KN), and an alicyclic olefin polymer (manufactured by Nippon Zeon Co., Ltd., “ZEONOR 1420R”, (“ZEONOR” is a registered trademark, the same applies hereinafter) ) As a raw material, injection molding was performed under the conditions of a cylinder temperature of 320 ° C., a holding pressure of 50 MPa, a holding pressure time of 3 seconds, and a mold temperature of 130 ° C. to form a light diffusion plate 631 schematically shown in FIG. Light diffusing plate 631 thus obtained had a thickness of 2 mm, a length (sides 631L direction in FIG. 6) 1018mm × width (side 631W ₁ and 631W in FIG ₂ direction) 573Mm rectangular plate-shaped, its It had a predetermined uneven structure on both sides. A flat plate having the same material as that of the diffusion plate and having a thickness of 2 mm and having no concavo-convex structure was produced under the same conditions as described above, and the light transmittance was measured to be 92%.

7, a light diffusing plate 631 shown in FIG. 6 is a partial side view as seen from the side 631W ₂ side. On one surface 631A of the light diffusing plate 631 (used as an exit surface), a triangular linear prism (triangular prism) 661 having a cross section with an apex angle 661T of 100 ° is disposed at a pitch (distance 661W) of 70 μm. There is no gap in the flat part (so that there is no flat part, that is, so that the triangular base corners adjacent to each other are in contact with each other), the light diffusion plate 631 is formed substantially parallel to the direction of the long side 631L. did.

On the other hand, the other surface 631B of the light diffuser plate 631 (used as an incident surface), as a boundary the 60mm line 631C from the side 631W _1, provided with different directions of the triangular prism. The side 631W ₂ side from the line 631C, as shown in FIG. 7, a plurality of types of triangular prisms 662 having different apex angles 662T, was placed at a predetermined mixing ratio. All of the triangular prisms 662 were formed substantially parallel to the direction of the long side 631L of the light diffusion plate 631. The predetermined pattern will be described later.

Surface 631B of the light diffusion plate 631, the side 631W ₁ side from the line 631C, as shown in FIG. 9, the triangular linear prisms (triangular prism) 663 of the cross section the apex angle 80 °, a pitch 70 [mu] m, flat gap without such portions (so that flat portion is not present, i.e., in contact said triangular base angle portions adjacent to each other), and substantially parallel to the side 631W _1. As described later, when assembling the backlight device, when viewed from the upper surface of the apparatus, in between the sides 631W ₁ and line 631C, the center line 116F is positioned straight pipe portion 110X in the bent portion 110C of the fluorescent tube 110 The backlight device was configured so that the distances 652A and 652B were equal.
When the surface 631A of this light diffusion plate was polished and the residual stress was measured, the maximum was 1 MPa and the minimum was 0.3 MPa.

The pattern of the triangular prism 662 will be described with reference to FIGS.
In a state where the light diffusing plate 631 is assembled in the direct type backlight device, the distance between the center 616H of the hot cathode tube lamp 610A and the center 616PB of the adjacent hot cathode tube lamp 610B corresponds to the point 616PA. The section of the distance to be divided was divided into 17 types of zones, which were designated as 616ZA to 616ZQ in order from the closest to the point 616PA. The range of each zone (the distance in the left-right direction in FIG. 8) was as shown in FIG. In each zone of the light incident surface 631B of the light diffusing plate 631, prism-shaped convex portions having a triangular cross section with an apex angle of 140 ° to 170 ° are provided at a mixing ratio shown in FIG. The prism pitch was 70 μm in all zones. In FIG. 8, for simplification, zones are described only for the region on the left side of the line 616H. Of course, a zone symmetrical to this is also provided in the region on the right side of the line 616.

In FIG. 34, A to Q indicate regions 616ZA to 616ZQ, respectively. The notation of FIG. 34 shows the arrangement of the convex portions in the repeating unit of the concave-convex structure pattern. For example, in the case of the region 616ZD, one unit is a concavo-convex structure in which one triangular convex portion having an apex angle of 170 ° and three triangular convex portions having an apex angle of 160 ° are adjacent to each other, and this unit is repeated. Shows the structure.
In the direct type backlight device, the transmittances of the portions corresponding to the region X and the region Y were 45% and 84%, respectively.

(1-4: assembly of backlight device)
Three hot-cathode tube lamps obtained in (1-2) were attached in parallel to the inner dimension length direction of the reflector. The bent portion 110C is installed so that all three hot-cathode tube lamps are arranged on the same side. From the center line 116F of the straight tube portion 116X in the bent portion, the short side of the direct type backlight device (light diffusion shown in FIG. 6). the distance to the wall side) corresponding to the side 631W ₁ side of the plate 631 was 30 mm. The center-to-center distances 651A and 651B (FIG. 6) of the hot cathode tube lamp were 90 mm, and the distance from the reflector to the center of the hot cathode tube lamp (610PA, 610PB, FIG. 8) was 9.75 mm. The vicinity of the electrode part was fixed with a silicone sealant, and the operation circuit 140 was attached. This operation circuit (corresponding to a ballast) includes a lighting circuit and a preheating circuit each including a ballast choke type inverter circuit.
Further, it is made of polycarbonate resin (made by Idemitsu Kosan Co., Ltd., Toughlon URZ2502, ("Taflon" is a registered trademark, the same shall apply hereinafter)), as shown in FIG. A support pin 2300 having a shape of a 1 mm hemisphere and a height of 2331 having a height of 2531 was attached to the position shown in Fig. 6. At this time, all the positions of the pins were the two straight fluorescent tube straight portions (in Fig. 3). 110S) is an intermediate position (ie, a position at an equal distance from both of the two straight line portions of the fluorescent tube).

In FIG. 6, the positional relationship on a plane when these pins 2300 and other members are seen from the upper surface is shown. In sides 631W ₁ and 100mm both distance and the distance from the line 671D to line 671E from the midline 671D to line 671C is a 631W _2, the distance between the sides 631W ₂ and line 671G is 100mm, the sides 631W ₂ and line 671F the distance a 200 mm, the distance of the distance between the sides 631W ₁ and line 671A is 100 mm, the sides 631W ₁ and line 671B was 200 mm. The distance 616K of the pin closest to the emitter position of the hot cathode tube lamp 110 is about 110 mm. The distance 616J between the pin and the nearest pin is about 134 mm.
Next, the surface on which the pattern shown in FIG. 34 is formed is directed to the hot cathode tube lamp side, and as shown in FIG. 6, the side 631W ₁ corresponds to the bent portion side of the hot cathode tube lamp 110 and the bent portion 110C center line 116F of the straight pipe portion 116X is, so as to be positioned exactly in the middle between the sides 631W ₁ and line 631C, was placed on the reflective plate formed the light diffusing plate 631 from the reflective sheet sticking aluminum case. At this time, the distance (the distance 653 in FIG. 8) between the center of the hot cathode tube lamp 110 and the light incident surface 631B of the light diffusion plate 631 was 15.25 mm.

  Further, on the light emitting surface 631A side of the light diffusing plate 631, a prism sheet ("BEFIII-10T" manufactured by Sumitomo 3M Co., Ltd.) and a diffusing sheet ("light up 188GM3" manufactured by Kimoto Co., Ltd.), each corresponding to an optical sheet. ) Were installed in this order to obtain a direct type backlight device. The prism sheet was installed with the longitudinal direction of the prism parallel to the straight portion of the hot cathode tube lamp.

Next, with respect to the obtained direct backlight device, the preheating circuit was adjusted, and the filament portion was energized with a current of 400 mA to maintain the emitter surface temperature at 800 ° C. Further, the lighting circuit was adjusted, and a hot cathode tube lamp was lit by applying a voltage of 400 V between the filaments at both ends. The current due to the voltage applied to the lighting was 150 mA.
Using a two-dimensional color distribution measuring apparatus, the luminance in the front direction at 100 points was measured at equal intervals along the line 671D in FIG. 6, and the luminance unevenness (vertical) described below was obtained. The central brightness measurement was 10,000 cd / m ² . In addition, the brightness of the central portion of the straight tube portions 116X in a by and bent portion in the line 116F, and the luminance of the position distant 50mm toward the sides 631W ₂ from the portion was measured, the luminance unevenness to be described below ( Horizontal) was measured.
According to the following formulas 1-3, the average luminance (front luminance) LA, luminance unevenness (vertical) LU1, and luminance unevenness (horizontal) LU2 in the front direction were obtained. The luminance unevenness (vertical) was 1.5%, and the luminance unevenness (horizontal) was 6.3%. When the time until the luminance reached 50% of the initial brightness was regarded as the lifetime of the backlight, the lifetime was 60,000 hours. The results are shown in FIG.
Brightness average value LA = (L1 + L2) / 2 (Formula 1)
Luminance unevenness (vertical) LU1 = ((L1-L2) / LA) × 100 (Formula 2)
L1: Average brightness maximum value just above a plurality of installed hot-cathode tube lamps L2: Average minimum value sandwiched between maximum values Brightness unevenness (horizontal) LU2 = ((L3-L4) / (L3 + L4 ) / 2) × 100 (Formula 3)
L3: Average brightness just above the middle position in the length direction of the bent portion L4: Average brightness just above the inner side in the length direction of the bent portion, 50 mm inside, parallel to the straight line portion

  Note that the luminance unevenness is an index indicating the uniformity of the luminance, and when the luminance unevenness is bad, the numerical value becomes large.

With the light diffusing plate, prism sheet, and diffusing sheet placed, the distribution of infrared rays was measured with a Fastvert S-2400 manufactured by Soma Optics (wavelength 843 nm, at a position directly above the emitter 15 mm away from the electrode of the hot cathode tube lamp). The measured value α is the measured value β at the intermediate position between the lamp moved parallel to the short side of the light diffusion plate from that position).
α = 0.040 μW / (cm ² · nm), β = 0.028 μW / (cm ² · nm), β / α = 0.70. Even if the VA type liquid crystal panel taken out from the liquid crystal television (Sharp Corporation Aquos LC-46GX1W, (“Aquos” is a registered trademark, the same shall apply hereinafter)) is mounted on this backlight and lighted for 100 hours, the display is not particularly disturbed. It was. Even in an IPS type liquid crystal panel taken out from a liquid crystal television (HDTV Model: 47LB5D manufactured by LG Electronics), the display was not disturbed in 100 hours.
Further, no warping was observed on the light diffusion plate during the life test, and the luminance unevenness in the vicinity of the electrode was not increased.

  Further, as a control light diffusing plate, except that the light incident surface and the light emitting surface are flat and there is no uneven structure and printing, the same light diffusing plate is manufactured, replaced with the light diffusing plate, the backlight device is driven, As a result of temperature measurement, it was confirmed that the light control unit in the apparatus of this example had a predetermined heat transfer function and heat diffusion function.

<Example 2>
A direct type backlight device was prepared in the same manner as in Example 1 except that the filament current for preheating was 500 mA and the emitter surface temperature was maintained at 820 ° C. For the obtained direct type backlight device, the luminance and luminance unevenness, the transmittance of the portion corresponding to the region X and the region Y, the residual stress of the light diffusion plate, the amount of infrared rays, and the lifetime were evaluated in the same manner as in Example 1. The transmittances of the portions corresponding to the region X and the region Y were 60% and 80%, respectively. The other results are shown in FIG.

In addition, the surface temperature of the light diffusing plate incident surface was measured. One hour after the surface temperature reached equilibrium, the temperature immediately above the emitter was 88 ° C., and 41 ° C. directly above the center of the hot cathode tube lamp in the longitudinal direction.
The surface temperature of the light diffusing plate exit surface was measured. In 1 hour after the surface temperature reaches the equilibrium temperature at an intermediate position in the length direction of the bent portion (in FIG. 3, the projection of the midpoint 116P ₃ axes 116F on the light diffusing plate emitting surface position) 35 ° C.
Similarly to Example 1, a VA type liquid crystal panel or an IPS type liquid crystal panel is mounted and a lighting test for 100 hours, a warp test on a light diffusion plate during a life test, a luminance unevenness test near the electrode, a transmission of a light control unit. When the confirmation test of the heat function and the heat diffusion function was carried out, the result was the same as in Example 1.

<Example 3>
A direct type backlight device was produced in the same manner as in Example 2 except that the filament current for preheating was 600 mA and the emitter surface temperature was maintained at 850 ° C. For the obtained direct type backlight device, the luminance and luminance unevenness, the transmittance of the portion corresponding to the region X and the region Y, the residual stress of the light diffusion plate, the amount of infrared rays, and the lifetime were evaluated in the same manner as in Example 1. The transmittances of the portions corresponding to the region X and the region Y were 60% and 80%, respectively. The other results are shown in FIG.
Similarly to Example 1, a VA type liquid crystal panel or an IPS type liquid crystal panel is mounted and a lighting test for 100 hours, a warp test on a light diffusion plate during a life test, a luminance unevenness test near the electrode, a transmission of a light control unit. When the confirmation test of the heat function and the heat diffusion function was carried out, the result was the same as in Example 1.

<Example 4>
The concavo-convex structure pattern of the light diffusing plate is as described in detail below, the distance between the straight portions of the hot cathode tube lamp is 100 mm, the depth of the reflector and the pin height 2331 (see FIG. 23) are 32.5 mm. A direct type backlight device was produced in the same manner as in Example 2 except that the distance from the center 616PA and 616PB of the fluorescent tube to the diffusion plate incident surface 631B was 23.75 mm. The outline of the pin arrangement is as shown in FIG. 6, but the pin is shifted in the width direction (vertical direction of the drawing in FIG. 6) in accordance with the interval of the linear portion of the hot cathode tube lamp being 100 mm. The distance from the axis 616G of the straight line portion to the pin was 50 mm. The distance 616K of the pin closest to the emitter position of the hot cathode tube lamp 110 is about 112 mm. The distance 616J between the pin and the nearest pin is about 141 mm.

The obtained direct type backlight device is lit under the same conditions as in Example 2, and the luminance and luminance unevenness, the transmittance corresponding to the region X and the region Y, the position directly above the emitter and the longitudinal direction of the hot cathode tube lamp The surface temperature of the light diffusing plate entrance surface at the center, the surface temperature of the light diffusing plate exit surface at the intermediate position in the length direction of the bent portion, the residual stress of the light diffusing plate, the amount of infrared rays, and the lifetime were evaluated. The transmittances of the portions corresponding to the region X and the region Y were 60% and 80%, respectively. The other results are shown in FIG.
Similarly to Example 1, a VA type liquid crystal panel or an IPS type liquid crystal panel is mounted and a lighting test for 100 hours, a warp test on a light diffusion plate during a life test, a luminance unevenness test near the electrode, a transmission of a light control unit. When the confirmation test of the heat function and the heat diffusion function was carried out, the result was the same as in Example 1.

  The uneven structure on the light diffusing plate used in this example will be described with reference to FIG. As shown in FIG. 10, with the light diffusing plate 1031 attached to the direct type backlight device, an intermediate 1016H at a distance from the center 1016PA of the hot cathode tube lamp 1010A to the center 1016PB of the adjacent hot cathode tube lamp 1010B; The section of the distance corresponding to the point 1016PA is divided into three zones, and divided into three zones of 1016ZA (9mm), 1016ZB (17.5mm) and 1016ZC (23.5mm) in order from the point closest to the point 1016PA. It was.

  As shown in FIG. 11, the light emitting surface 1031A of the light diffusion plate 1031 shown in FIG. 10 has a flat prism-shaped convex portion 1061 having a triangular cross section with an apex angle of 100 ° and a base of 70 μm, as shown in FIG. There was no gap in a small part (so that a flat part does not exist, that is, the triangular bottom corners adjacent to each other are in contact with each other).

  On the other hand, among the zones of the light incident surface 1031B of the light diffusing plate 1031, the zone 1016ZA is a flat surface. In the zone 1016ZB, prism-shaped convex portions 1064 having a triangular cross section and flat portions 1065 are alternately provided as shown in FIG. However, the apex angle of the convex portion 1064 was 130 °, the base 1064W was 70 μm, and the width 1065W of the flat portion was 70 μm. In the zone 1016ZC, prism-shaped convex portions having a triangular cross section with an apex angle of 130 ° and a base of 70 μm were provided without a flat portion gap.

<Example 5>
A direct type backlight device was prepared in the same manner as in Example 2 except that the uneven structure on the incident surface of the light diffusing plate was changed to the following mode. The obtained direct type backlight device is lit under the same conditions as in Example 2, and the luminance and luminance unevenness, the transmittance corresponding to the region X and the region Y, the position directly above the emitter and the longitudinal direction of the hot cathode tube lamp The surface temperature of the light diffusing plate entrance surface at the center, the surface temperature of the light diffusing plate exit surface at the intermediate position in the length direction of the bent portion, the residual stress of the light diffusing plate, the amount of infrared rays, and the lifetime were evaluated. The transmittances of the portions corresponding to the region X and the region Y were 60% and 80%, respectively. The other results are shown in FIG.
Similarly to Example 1, a VA type liquid crystal panel or an IPS type liquid crystal panel is mounted and a lighting test for 100 hours, a warp test on a light diffusion plate during a life test, a luminance unevenness test near the electrode, a transmission of a light control unit. When the confirmation test of the heat function and the heat diffusion function was carried out, the result was the same as in Example 1.

The uneven structure of the incident surface of the light diffusing plate used in this example will be described with reference to FIG. In FIG. 12, the position of the line 1231C in the light diffusion plate 1231 is the same as that of the line 631C in FIG. Same from the line 1231D of position 20mm apart from the line 1231C to sides 1231W _2, in the area between the up side 1231W ₂ is described in Embodiment 1 and FIG. 6, the pattern in the region of from the line 631C to the side 631W ₂ The pattern of was provided. On the other hand, in the region between the line 1231W1 to the line 1231C, as described in Examples 1 and 6, provided with the same pattern as in the region to the side 631W ₁ from line 631C. In the region between the line 1231C and the line 1231D, a pattern having a shape in which a quadrangular pyramid constituted by slopes having the same angle as the prisms in both regions is inverted is provided. That is, in a mold for molding the surface, in the region of from the line 1231C to line 1231D, a side 1231L direction parallel digging the same groove as that provided in the region 1231D～1231W _2, in addition A square pyramid is formed by digging a groove similar to that provided in the regions 1231W _{1 to} 1231C in a direction parallel to the sides 1231W ₁ and 1231W _2, and a shape obtained by transferring the square weight is formed in the regions 1231C to 1231C of the light diffusion plate 1231. 1231D.

<Example 6>
A direct type backlight device was prepared in the same manner as in Example 2 except that the uneven structure on the incident surface of the light diffusing plate was changed to the following mode. The obtained direct type backlight device is lit under the same conditions as in Example 2, and the luminance and luminance unevenness, the transmittance corresponding to the region X and the region Y, the position directly above the emitter and the longitudinal direction of the hot cathode tube lamp The surface temperature of the light diffusing plate entrance surface at the center, the surface temperature of the light diffusing plate exit surface at the intermediate position in the length direction of the bent portion, the residual stress of the light diffusing plate, the amount of infrared rays, and the lifetime were evaluated. The transmittances of the portions corresponding to the region X and the region Y were 60% and 80%, respectively. The other results are shown in FIG.

  Similarly to Example 1, a VA type liquid crystal panel or an IPS type liquid crystal panel is mounted, and a 100-hour lighting test, a warp test on a light diffusion plate during a life test, a luminance unevenness test near the electrode, a transmission of a light control unit. When the confirmation test of the heat function and the heat diffusion function was carried out, the result was the same as in Example 1.

  The uneven structure of the incident surface of the light diffusing plate used in this example will be described with reference to FIG. In this example, the incident surface of the light diffusing plate was not provided with an uneven structure, and printing shown in FIG. 13 was performed instead. In FIG. 13, a line 1316G indicates a line obtained by projecting the axis 116G of the fluorescent tube 110 onto the light diffusion plate. A line 1316F indicates a line obtained by projecting the axis 116F of the fluorescent tube 110 onto the light diffusion plate. On the incident surface of the light diffusion plate 1331 used in this example, printing was performed in a zone 1371 along the fluorescent tube 110 as shown in FIG.

  The zone 1371 will be described in more detail with reference to FIG. The area up to the distance indicated by the arrow 1371A around the line (1316G and 1316F; 1316G in FIG. 14) projected from the axis of the fluorescent tube is defined as the zone 1371ZA, and the area from there to the distance indicated by the arrow 1371B is defined as the zone. 1371ZB. The distances indicated by arrows 1371A and 1371B are both 10 mm in this embodiment.

  For printing, white ink containing 25% by mass of titanium dioxide as a pigment was used, and circular dots having a diameter of 100 μm were printed side by side uniformly in each zone. The density of the dots was adjusted so that 50% of the zone area was covered with the printing surface in the zone 1371ZA and 20% of the zone area was covered with the printing surface in the zone 1371ZB.

<Example 7>
As a raw material for the light diffusion plate, 99.7 parts of an alicyclic olefin polymer (manufactured by Zeon Corporation, “Zeonor 1420R”) instead of the alicyclic olefin polymer, and a crosslinked product of a polysiloxane polymer having an average particle diameter of 2 μm In the same manner as in Example 2, the direct-type backlight device was used except that the resin composition mixed with 0.3 part of the fine particles made of and the structure of the light diffusing plate and the light reflecting plate was as follows: Created. A flat plate having the same material as that of the diffusion plate and having a thickness of 2 mm and having no concavo-convex structure was produced under the same conditions as described above, and the light transmittance was measured to be 85%.

  The obtained direct type backlight device is lit under the same conditions as in Example 2, and the luminance and luminance unevenness, the transmittance corresponding to the region X and the region Y, the position directly above the emitter and the longitudinal direction of the hot cathode tube lamp The surface temperature of the light diffusing plate entrance surface at the center, the surface temperature of the light diffusing plate exit surface at the intermediate position in the length direction of the bent portion, the residual stress of the light diffusing plate, the amount of infrared rays, and the lifetime were evaluated. The transmittances of the portions corresponding to the regions X and Y were 60% and 80%, respectively. The other results are shown in FIG.

  Similarly to Example 1, a VA type liquid crystal panel or an IPS type liquid crystal panel is mounted, and a 100-hour lighting test, a warp test on a light diffusion plate during a life test, a luminance unevenness test near the electrode, a transmission of a light control unit. When the confirmation test of the heat function and the heat diffusion function was carried out, the result was the same as in Example 1.

  The structure of the light diffusion plate used in this example will be described. The light emitting surface of the light diffusing plate has a cross-section (longitudinal direction) of a part of a circle having a width of 70 μm, a depth of 22.3 μm, a pitch of 70 μm, and a radius of 38.6 μm (slightly smaller than a semicircle). The ridge-shaped convex portion having a cross-section cut by a plane perpendicular to the surface has no gap in the flat portion (no flat portion exists, that is, the ridge-shaped bottom corner portions adjacent to each other are in contact with each other). Provided).

  On the other hand, the light incident surface of the light diffusing plate was a surface having no unevenness, and the same printing as in Example 6 was performed.

  The structure of the reflector used in this example will be described with reference to FIGS. In this example, MCPET (product name, Furukawa Electric Co., Ltd.) was used as the sheet to be attached instead of E6SV manufactured by Toray. In addition, triangular prism-shaped protrusions 1581 are provided at each of five positions between the six linear portions of the three fluorescent tubes 1510 on the reflection plate 1501, and reflection sheets are similarly provided on the inclined surfaces thereof. . The apex angle θ1582 of the protrusion 1581 is 90 °, the height 1582H is 20 mm, and the protrusion centerline 1516H is positioned so as to be positioned at the midpoint between the centers 1510PA and 1510PB of the adjacent fluorescent tube linear portions (1510A, 1510B). . The distance from the axis 1516F of the bent portion of the fluorescent tube 1510 to the end portion 1582A of the protrusion 1581 was 20 mm.

<Example 8>
As a raw material for the light diffusion plate, 97.4 parts of an alicyclic olefin polymer (manufactured by Zeon Corporation, “Zeonor 1420R”) instead of the alicyclic olefin polymer and a cross-linked product of a polysiloxane polymer having an average particle diameter of 2 μm In addition to using a resin composition mixed with 2.6 parts of the fine particles, the distance between the linear parts of the hot cathode tube lamp is set to 100 mm, the structure of the light diffusing plate is as shown below, and the position of the pin 2300 is implemented. A direct type backlight device was produced in the same manner as in Example 7 except that it was the same as in Example 4. A flat plate having the same material as that of the diffusion plate and having a thickness of 2 mm and having no concavo-convex structure was produced under the same conditions as described above, and the light transmittance was measured to be 55%.
The obtained direct type backlight device is lit under the same conditions as in Example 2, and the luminance and luminance unevenness, the transmittance corresponding to the region X and the region Y, the position directly above the emitter and the longitudinal direction of the hot cathode tube lamp The surface temperature of the light diffusing plate entrance surface at the center, the surface temperature of the light diffusing plate exit surface at the intermediate position in the length direction of the bent portion, the residual stress of the light diffusing plate, the amount of infrared rays, and the lifetime were evaluated. The transmittances of the portions corresponding to the region X and the region Y were 60% and 80%, respectively. The other results are shown in FIG.
Similarly to Example 1, a VA type liquid crystal panel or an IPS type liquid crystal panel is mounted and a lighting test for 100 hours, a warp test on a light diffusion plate during a life test, a luminance unevenness test near the electrode, a transmission of a light control unit. When the confirmation test of the heat function and the heat diffusion function was carried out, the result was the same as in Example 1.

  The structure on the light diffusing plate used in this embodiment will be described. The light exit surface of the light diffusing plate was smooth on the entire surface, and was neither printed nor uneven. On the other hand, the light incident surface was a smooth surface without unevenness, and the same printing as in Example 6 was performed except that the following points were changed. The changes will be described with reference to FIGS. 13 and 14. The center position of the zone 1371 is adapted to the position where printing is performed by projecting the axis 1316G of the fluorescent tube whose straight line interval is 100 mm onto the light diffusion plate. I tried to do it. The density of dots was adjusted so that 65% of the zone area was covered with the printing surface in the zone 1371ZA and 30% of the zone area was covered with the printing surface in the zone 1371ZB.

<Example 9>
A direct type backlight device was produced in the same manner as in Example 2 except that the light diffusion plate was changed to the following mode.

The light diffusion plate used in this example will be described with reference to FIG. The entire surface of the light exiting surface of the light diffusing plate was provided with unevenness similar to that of the light exiting surface of the light diffusing plate in Example 2. In the region between the lines 1731C to 1731W _{2 on the} incident surface, the same unevenness as the region between the lines 631C to 631W ₂ (FIG. 6) in Example 2 was provided. On the other hand, the region between the lines 1731C to 1731W ₁ was not provided with unevenness, and printing was performed in a zone 1771 along the bent portion of the fluorescent tube. Position of the line 1731C was from the side 1731W ₁ the distance 50 mm.

The zone 1771 will be described in more detail with reference to FIG. Zone 1771 is a rectangular area around the location where the projection of the midpoint 116P ₃ axes 116F of the bent portion of the fluorescent tube 110 to the light diffusing plate, inner zone 1771ZA the projection axis 116F light diffusing plate The distance from the line (arrow 1771A1 in FIG. 24) was within the range of 10 mm, and the outer zone 1771ZB was within the range of 10 mm from the distance (arrow 1771B1 in FIG. 24). Further, parallel lines 116E to the axis 116G of the linear portion of the street fluorescent tube 110 intermediate points 116P ₃ from the line obtained by projecting the light diffusion plate, the distance to the edge of the zone 1771ZA (in Fig. 24 arrow 1771A2) is a 55mm The distance from that to the edge of the zone 1771ZB (arrow 1771B2 in FIG. 24) was 10 mm.

  For printing, white ink containing 25% by mass of titanium dioxide as a pigment was used, and circular dots having a diameter of 100 μm were printed side by side uniformly in each zone. The density of the dots was adjusted so that 50% of the zone area was covered with the printing surface in zone 1771ZA and 20% of the zone area was covered with zone 1771ZB.

The obtained direct type backlight device is lit under the same conditions as in Example 2, and the luminance and luminance unevenness, the transmittance corresponding to the region X and the region Y, the position directly above the emitter and the longitudinal direction of the hot cathode tube lamp The surface temperature of the light diffusing plate entrance surface at the center, the surface temperature of the light diffusing plate exit surface at the intermediate position in the length direction of the bent portion, the residual stress of the light diffusing plate, the amount of infrared rays, and the lifetime were evaluated. The transmittances of the portions corresponding to the region X and the region Y were 60% and 80%, respectively. The other results are shown in FIG.
Similarly to Example 1, a VA type liquid crystal panel or an IPS type liquid crystal panel is mounted and a lighting test for 100 hours, a warp test on a light diffusion plate during a life test, a luminance unevenness test near the electrode, a transmission of a light control unit. When the confirmation test of the heat function and the heat diffusion function was carried out, the result was the same as in Example 1.

<Example 10>
A direct type backlight device was produced in the same manner as in Example 2 except that the light diffusing plate and the hot cathode tube lamp were changed to the following modes.
The obtained direct type backlight device is lit under the same conditions as in Example 2, and the luminance and luminance unevenness, the transmittance corresponding to the region X and the region Y, the position directly above the emitter and the longitudinal direction of the hot cathode tube lamp The surface temperature of the light diffusing plate entrance surface at the center, the surface temperature of the light diffusing plate exit surface at the intermediate position in the length direction of the bent portion, the residual stress of the light diffusing plate, the amount of infrared rays, and the lifetime were evaluated. The transmittances of the portions corresponding to the region X and the region Y were 60% and 80%, respectively. The other results are shown in FIG.
Similarly to Example 1, a VA type liquid crystal panel or an IPS type liquid crystal panel is mounted and a lighting test for 100 hours, a warp test on a light diffusion plate during a life test, a luminance unevenness test near the electrode, a transmission of a light control unit. When the confirmation test of the heat function and the heat diffusion function was carried out, the result was the same as in Example 1.

The structure of the light diffusing plate and the hot cathode tube lamp used in this example will be described. The entire surface of the light exiting surface of the light diffusing plate was provided with unevenness similar to that of the light exiting surface of the light diffusing plate in Example 2. On the entire incident surface, the same unevenness as the region between the lines 631C to 631W ₂ (FIG. 6) in Example 2 was provided. On the other hand, on the fluorescent tube, silicon dioxide particles were adhered to the bent portion and the region on the emission surface side so that the light transmittance of the glass surface was 70%. This will be described in more detail with reference to FIGS. 18 and 19. On the glass surface in a region 1810R surrounded by lines 1816A1 and A2 which are bent portions 1810C of the fluorescent tube and extend inside the straight portion 1810S. In addition, silicon dioxide particles were adhered to a region 1872 on the emission surface side (upper side in FIG. 19).

<Example 11>
A direct type backlight device was prepared in the same manner as in Example 8 except that the incident surface of the light diffusing plate was printed and the hot cathode tube lamp was in the form shown below.

  An aspect of printing on the incident surface of the light diffusing plate used in this example will be described with reference to FIG. In the light diffusion plate 2031 shown in FIG. 20, a straight belt-like zone 2073 is provided around the position where the axis 2016G of the linear portion of the fluorescent tube is projected onto the light diffusion plate, and printing is performed in the zone. Similarly to the zone 1371 shown in FIG. 14, the zone 2073 is further divided into two zones (corresponding to 1371ZA and 1371ZB in FIG. 14). The distance from the inner zone edge to the center line (corresponding to the arrow 1371A in FIG. 14) was 10 mm, and the outer zone width (corresponding to the arrow 1371B in FIG. 14) was 10 mm.

  For printing, white ink containing 25% by mass of titanium dioxide as a pigment was used, and circular dots having a diameter of 100 μm were printed side by side uniformly in each zone. The dot density was adjusted so that 65% of the zone area was covered with the printing surface in the inner zone and 30% of the zone area was covered with the printing surface in the outer zone.

  Further, as the hot cathode tube lamp, similar to the one used in Example 10, the silicon dioxide particles are formed so that the light transmittance of the glass surface is 70% in the bent portion of the fluorescent tube and the region on the emission surface side. (However, the interval between the straight portions is 100 mm as in Example 8).

The obtained direct type backlight device is lit under the same conditions as in Example 2, and the luminance and luminance unevenness, the transmittance corresponding to the region X and the region Y, the position directly above the emitter and the longitudinal direction of the hot cathode tube lamp The surface temperature of the light diffusing plate entrance surface at the center, the surface temperature of the light diffusing plate exit surface at the intermediate position in the length direction of the bent portion, the residual stress of the light diffusing plate, the amount of infrared rays, and the lifetime were evaluated. The transmittances of the portions corresponding to the region X and the region Y were 60% and 80%, respectively. The other results are shown in FIG.
Similarly to Example 1, a VA type liquid crystal panel or an IPS type liquid crystal panel is mounted and a lighting test for 100 hours, a warp test on a light diffusion plate during a life test, a luminance unevenness test near the electrode, a transmission of a light control unit. When the confirmation test of the heat function and the heat diffusion function was carried out, the result was the same as in Example 1.

<Example 12>
As a hot cathode tube lamp, a fluorescent tube having an outer diameter of 32.5 mm is used, the pin height 2331 (see FIG. 23) is changed so that the distance between the reflector and the diffuser is 42.0 mm. A direct type backlight device was produced in the same manner as in Example 2 except that the distance from the center of the hot cathode tube lamp to 18.25 mm.
The obtained direct type backlight device was turned on under the same conditions as in Example 1, and the luminance and luminance unevenness, the transmittance corresponding to the region X and the region Y, the residual stress of the light diffusion plate, and the lifetime were evaluated. did. The transmittances of the portions corresponding to the region X and the region Y were 60% and 80%, respectively. The other results are shown in FIG.
Similarly to Example 1, a VA type liquid crystal panel or an IPS type liquid crystal panel is mounted and a lighting test for 100 hours, a warp test on a light diffusion plate during a life test, a luminance unevenness test near the electrode, a transmission of a light control unit. When the confirmation test of the heat function and the heat diffusion function was carried out, the result was the same as in Example 1.

<Example 13>
A direct type backlight device was prepared in the same manner as in Example 2 except that a hot cathode tube lamp having a fluorescent tube glass thickness of 3 mm was used.
The obtained direct type backlight device was turned on under the same conditions as in Example 1, and the luminance and luminance unevenness, the transmittance corresponding to the region X and the region Y, the residual stress of the light diffusion plate, and the lifetime were evaluated. did. The transmittances of the portions corresponding to the region X and the region Y were 60% and 80%, respectively. The other results are shown in FIG.
Similarly to Example 1, a VA type liquid crystal panel or an IPS type liquid crystal panel is mounted and a lighting test for 100 hours, a warp test on a light diffusion plate during a life test, a luminance unevenness test near the electrode, a transmission of a light control unit. When the confirmation test of the heat function and the heat diffusion function was carried out, the result was the same as in Example 1.

<Example 14>
A direct type backlight device was prepared in the same manner as in Example 2 except that the inverter was a transformer type.
The obtained direct type backlight device is lit under the same conditions as in Example 2, and the luminance and luminance unevenness, the transmittance corresponding to the region X and the region Y, the position directly above the emitter and the longitudinal direction of the hot cathode tube lamp The surface temperature of the light diffusing plate entrance surface at the center, the surface temperature of the light diffusing plate exit surface at the intermediate position in the length direction of the bent portion, the residual stress of the light diffusing plate, the amount of infrared rays, and the lifetime were evaluated. The transmittances of the portions corresponding to the region X and the region Y were 60% and 80%, respectively. The other results are shown in FIG.
Similarly to Example 1, a VA type liquid crystal panel or an IPS type liquid crystal panel is mounted and a lighting test for 100 hours, a warp test on a light diffusion plate during a life test, a luminance unevenness test near the electrode, a transmission of a light control unit. When the confirmation test of the heat function and the heat diffusion function was carried out, the result was the same as in Example 1.

<Example 15>
Similar to Example 2, except that the pin height 2131 is changed so that the distance between the reflector and the diffuser entrance surface is 200 mm, and the distance from the center of the fluorescent tube to the diffuser entrance surface is 190.25 mm. A backlight device was created.
The obtained direct type backlight device was turned on under the same conditions as in Example 1, and the luminance and luminance unevenness, the transmittance corresponding to the region X and the region Y, the residual stress of the light diffusion plate, and the lifetime were evaluated. did. The transmittances of the portions corresponding to the region X and the region Y were 60% and 80%, respectively. The other results are shown in FIG.
Similarly to Example 1, a VA type liquid crystal panel or an IPS type liquid crystal panel is mounted and a lighting test for 100 hours, a warp test on a light diffusion plate during a life test, a luminance unevenness test near the electrode, a transmission of a light control unit. When the confirmation test of the heat function and the heat diffusion function was carried out, the result was the same as in Example 1.

<Example 16>
The light diffusing plate and the backlight were the same as in Example 2 except that the conditions for injection molding of the light diffusing plate were changed to a cylinder temperature of 320 ° C., a holding pressure of 75 MPa, a holding pressure time of 6 seconds, and a mold temperature of 120 ° C. A device was made.
The obtained direct-type backlight device was lit under the same conditions as in Example 2, and the luminance and luminance unevenness, the transmittance corresponding to the regions X and Y, the position directly above the emitter and the longitudinal direction of the hot cathode tube lamp The surface temperature of the light diffusing plate entrance surface at the center, the surface temperature of the light diffusing plate exit surface at the intermediate position in the length direction of the bent portion, the amount of infrared rays, and the lifetime were evaluated. The transmittances of the portions corresponding to the region X and the region Y were 60% and 80%, respectively. The other results are shown in FIG.
Similarly to Example 1, a VA type liquid crystal panel or an IPS type liquid crystal panel is mounted and a lighting test for 100 hours, a warp test on a light diffusion plate during a life test, a luminance unevenness test near the electrode, a transmission of a light control unit. When the confirmation test of the heat function and the heat diffusion function was carried out, the result was the same as in Example 1.
When the triangular prism surface having an apex angle of 100 degrees of this light diffusion plate was polished and the residual stress was measured, the maximum was 15 MPa and the minimum was 2 MPa. The luminance unevenness at the center was as small as 1.5%, but warpage occurred near the electrode, resulting in a large luminance unevenness of 6.3%.

<Example 17>
A backlight device was produced in the same manner as in Example 2 except that the support pins 2300 were arranged as shown in FIG. In Figure 21, the position of the line 2171D is located through the midpoints of the sides 2131L, that is, equidistant from the sides 2131W ₁ and 2131W ₂ Metropolitan. Distance from the distance and edges 2131W ₂ from sides 2131W ₁ to the line 2171J to the line 2171K are all by 300 mm. The distance 2116K of the pin closest to the emitter position of the hot cathode tube lamp is 302 mm. The distance from the pin 2300 to the axis 2116G of the nearest straight line part is 45 mm.
The obtained direct type backlight device is lit under the same conditions as in Example 2, and the luminance and luminance unevenness, the transmittance corresponding to the region X and the region Y, the position directly above the emitter and the longitudinal direction of the hot cathode tube lamp The surface temperature of the light diffusing plate entrance surface at the center, the surface temperature of the light diffusing plate exit surface at the intermediate position in the length direction of the bent portion, the residual stress of the light diffusing plate, the amount of infrared rays, and the lifetime were evaluated. The transmittances of the portions corresponding to the region X and the region Y were 60% and 80%, respectively. The other results are shown in FIG.
Similarly to Example 1, a VA type liquid crystal panel or an IPS type liquid crystal panel is mounted and a lighting test for 100 hours, a warp test on a light diffusion plate during a life test, a luminance unevenness test near the electrode, a transmission of a light control unit. When the confirmation test of the heat function and the heat diffusion function was carried out, the result was the same as in Example 1.

  A convex 2.5 mm warp was generated on the hot cathode tube lamp side in the vicinity of the electrode part, and a 1.5 mm warp in the same direction was also generated in the central part. As a result, the luminance unevenness in the vicinity of the central portion was slightly large at 2.8%, and further increased to 4.5% in the vicinity of the electrode.

<Example 18>
A direct type backlight device including a reflector, a fluorescent lamp, and a light diffusing plate was produced.

(18-1: reflector)
The same reflector as in Example 1-1 (1-1) was prepared.

(18-2: Hot cathode tube lamp)
A hot cathode tube lamp having a fluorescent tube 110 and a filament portion 120 made of a U-shaped soda-lime glass having a shape schematically shown in FIG. 3 but having dimensions different from those used in Example 1 was prepared. . Referring to FIG. 3, in this example, the fluorescent tube 110 had an outer diameter of about 15.5 mm, a glass thickness of 0.7 mm, and a glass transmittance of 90%. The cross section of the fluorescent tube 110 in a plane perpendicular to the axes 116G and 116F was circular. The tube length of the straight portion 110S on the straight line side of the dotted line 110D of the fluorescent tube 110 is 580 mm, and these are connected by the bent portion 110C so that the interval 116G is 90 mm. The bent portion has a straight portion 116X having a center line 116F having a length of about 60 mm and an angle of 90 ° with the straight portion, and both ends of the portion 116X are via portions bent at a curvature radius of 13 mm. It was connected with the straight part 110S. At both ends of the fluorescent tube 110, an electrode 120 having an emitter (electron emitting material) 124 containing BaO, SrO, and CaO at a ratio of 1: 1: 1 applied and adhered onto a triple-coil tungsten filament 122 was installed. . Further, a three-wavelength light emitting phosphor is formed on the inner wall surface of the fluorescent tube 110, and mercury and 1 kPa of argon are sealed in the fluorescent tube 110.

(18-3: Light diffusion plate)
A light diffusion plate 2531 schematically shown in FIG. 25 was formed in the same manner as (1-3) of Example 1 except that the mold was changed to the following predetermined shape. Light diffusing plate 2531 thus obtained had a thickness 2 mm, a length (sides 2531W ₁ and 2531W ₂ direction in FIG. 25) 1018mm × width (side 2531L direction in FIG. 25) 573mm rectangular plate-shaped, its It had a predetermined uneven structure on both sides.

26, a light diffusing plate 2531 shown in FIG. 25 is a partial elevational sectional view as seen from the side 2531W ₂ side. On one surface 2531A (used as an exit surface) of the light diffusion plate 2531, a triangular linear prism (triangular prism) 2561 having a cross section with an apex angle 2561T of 100 ° is provided at a pitch (distance 2561W) of 70 μm. There is no gap in the flat part (so that there is no flat part, that is, so that the triangular bases adjacent to each other are in contact with each other), the light diffusion plate 2531 is formed substantially parallel to the direction of the short side 2531L. did.

On the other hand, the other surface 2531B of the light diffusing plate 2531 (used as an incident surface), as a boundary the 60mm line 2531C from the side 2531W _1, provided with different directions of the triangular prism. The side 2531W ₂ side from the line 2531C, as shown in FIG. 26, a plurality of types of triangular prisms 2562 having different apex angles 2562T, and arranged at a predetermined mixing ratio. All the triangular prisms 2562 were formed substantially parallel to the direction of the short side 631L of the light diffusion plate 2531. The arrangement and mixing ratio of the triangular prism 2562 were the same as those of the triangular prism 662 in the first embodiment.

On the surface 2531B of the light diffusing plate 2531, on the side 2531W ₁ from the line 2531C, as shown in FIG. gap without such portions (so that flat portion is not present, i.e., in contact said triangular base angle portions adjacent to each other), and substantially parallel to the side 2531W _1. As described later, when assembling the backlight device, when viewed from the upper surface of the apparatus, in between the sides 2531W ₁ and line 2531C, the center line 116F is positioned straight pipe portion 110X in the bent portion 110C of the fluorescent tube 110 The backlight device was configured so that the distances 2552A and 2552B were equal.

(18-4: Assembly of backlight device)
Five hot cathode tube lamps obtained in the above (18-2) were attached to the reflecting plate. The bent portion 110C is installed on the same side as the five hot-cathode tube lamps, and extends from the center line 116F of the straight tube portion 116X in the bent portion to the long side of the direct type backlight device (light diffusion shown in FIG. 25). the distance to the wall side) corresponding to the side 2531W ₁ side of the plate 2531 was 30 mm. The distances between the centers 2551A and 2551B (FIG. 25) of the straight portions of the hot cathode tube lamp were 90 mm, and the distance from the reflector to the center of the hot cathode tube lamp was 9.75 mm. The vicinity of the electrode part was fixed with a silicone sealant, and the operation circuit 140 was attached. This operation circuit (corresponding to a ballast) includes a lighting circuit and a preheating circuit each including a ballast choke type inverter circuit.
Further, the height 2331 is a shape made of a polycarbonate resin (Taflon URZ2502 manufactured by Idemitsu Kosan Co., Ltd.) shown in FIG. A support pin 2300 having a diameter of 25 mm was attached to the position shown in FIG. At this time, all the positions of the pins are intermediate positions of the axes 2516G of the two most recent fluorescent tube straight portions (that is, a position at an equal distance from both of the two most recent straight tube portions).

In FIG. 25, the positional relationship on a plane when these pins 2300 and other members are viewed from the upper surface is shown. Distance of the distance between the sides 2531W ₂ and line 2571G is 100 mm, the distance between the sides 2531W ₂ and line 2571F is 200 mm, the distance between the sides 2531W ₁ and line 2571A is 100 mm, the sides 2531W ₁ and line 2571B was 200 mm. The distance 2516K between the emitter position of the hot cathode tube lamp 110 and the nearest pin is about 110 mm. The distance 2516J between the pin and the nearest pin is about 134 mm.
Next, the surface on which the pattern shown in FIG. 34 are formed toward the hot cathode tube lamp side, as shown in FIG. 25, the sides 2531W ₁ corresponds to the bent portion side of the hot-cathode tube lamp 110, the bent portion 110C center line 116F of the straight pipe portion 116X is, so as to be positioned exactly in the middle between the sides 2531W ₁ and line 2531C, was placed on the reflective plate formed the light diffusing plate 2531 from the reflection sheet sticking aluminum case. At this time, the distance between the center of the hot cathode tube lamp 110 and the light incident surface of the light diffusion plate 2531 was 15.25 mm.

  Furthermore, a prism sheet (“BEFIII-10T” manufactured by Sumitomo 3M Co., Ltd.) and a diffusion sheet (manufactured by Kimoto Co., “light-up 188GM3”), each corresponding to an optical sheet, are provided on the light exit surface side of the light diffusion plate 2531. Were installed in this order to obtain a direct type backlight device. The prism sheet was installed with the longitudinal direction of the prism parallel to the straight portion of the hot cathode tube lamp.

The obtained direct type backlight device is lit under the same conditions as in Example 2, and the luminance and luminance unevenness, the transmittance corresponding to the region X and the region Y, the position directly above the emitter and the longitudinal direction of the hot cathode tube lamp The surface temperature of the light diffusing plate entrance surface at the center, the surface temperature of the light diffusing plate exit surface at the intermediate position in the length direction of the bent portion, the residual stress of the light diffusing plate, the amount of infrared rays, and the lifetime were evaluated. The transmittances of the portions corresponding to the region X and the region Y were 60% and 80%, respectively. The other results are shown in FIG.
Similarly to Example 1, a VA type liquid crystal panel or an IPS type liquid crystal panel is mounted and a lighting test for 100 hours, a warp test on a light diffusion plate during a life test, a luminance unevenness test near the electrode, a transmission of a light control unit. When the confirmation test of the heat function and the heat diffusion function was carried out, the result was the same as in Example 1.

<Example 19>
A direct type backlight device including a reflector, a fluorescent lamp, and a light diffusing plate was produced.

(19-1: reflector)
The same reflector as in Example 1-1 (1-1) was prepared.

(19-2: Hot cathode tube lamp)
A hot-cathode tube lamp having a fluorescent tube made of soda-lime glass and a filament portion having an N-shape schematically shown in FIG. 22 was prepared. The fluorescent tube included in this hot cathode tube lamp had an outer diameter of about 15.5 mm, a glass thickness of 0.7 mm, and a glass transmittance of 90%. The tube length of two straight portions including the end portion was 1020 mm, and the tube length of one straight portion not including the end portion was 490 mm. These three straight portions are arranged in parallel as shown in FIG. 22, and have an N-shaped structure connected by bent portions. The bent portion has a straight portion having a center line 2216F ₁ and 2216F ₂ having a length of about 60 mm and an angle of 90 ° with the straight portion, and both ends of the portion are bent at a curvature radius of 13 mm. And connected to the straight line portion. At both ends of the fluorescent tube, electrodes having an emitter (electron emitting material) containing BaO, SrO, and CaO in a ratio of 1: 1: 1 on a tungsten coil of a triple coil were installed. In addition, a three-wavelength light emitting phosphor was formed on the inner wall surface of the fluorescent tube, and mercury and 1 kPa of argon were sealed in the fluorescent tube.

(19-3: Light diffusing plate)
A light diffusing plate 2231 schematically shown in FIG. 22 was formed in the same manner as (1-3) in Example 1 except that the mold was changed to the following predetermined shape. The resulting light diffusing plate 2231, thickness 2 mm, the width (side 2231W ₁ and 2231W ₂ direction in FIG. 22) 573mm × length (side 2231L direction in FIG. 22) 1018mm rectangular plate-shaped, its It had a predetermined uneven structure on both sides.

  On one surface of the light diffusing plate 2231 (used as an exit surface), a triangular linear prism (triangular prism) having a cross section with an apex angle of 100 ° is formed with a pitch of 70 μm and no gap in a flat portion ( It was formed so as to be substantially parallel to the direction of the long side 2231L so that no flat portion was present (that is, the triangular base corner portions adjacent to each other were in contact with each other).

On the other hand, the other light diffusion plate 2231 to the surface (used as the incident surface), the distance boundary lines 2231C ₂ of 60mm distance from the line 2231C ₁ and edges 2231W ₂ of 60mm from the side 2231W _1, the direction of Different triangular prisms were provided. The region surrounded by lines 2231C ₁ and 2231C _2, was placed the same triangular prism and the area of the line 631～ sides 631W ₂ of the incident surface 631B of the diffusion plate 631 in the first embodiment. On the other hand, in a region surrounded by edges 2231W ₁ and line 2231C regions and sides 2231W ₂ and the line 2231C ₂ surrounded by _1, the incident surface 631B of the light diffusion plate 631 in the first embodiment, the line 631C sides 631W ₁ side A triangular prism similar to the region was placed.

(19-4: Assembly of backlight device)
Two hot-cathode tube lamps obtained in (19-2) were attached to the reflector in the form shown in FIG. Distance from the center line 2216F ₁ straight tube portion in the bent portion to the side 2231W ₁ side wall of the direct-type backlight device was set to 30 mm, to the side 2231W ₁ side wall of the direct-type backlight device from the centerline 2216F ₂ The distance was also 30 mm. The distance between the centers 2251A to 2251C (FIG. 22) of the straight portion of the hot cathode tube lamp was 90 mm, and the distance from the reflector to the center of the hot cathode tube lamp was 9.75 mm. The vicinity of the electrode part was fixed with a silicone sealant, and the operation circuit 140 was attached. This operation circuit (corresponding to a ballast) includes a lighting circuit and a preheating circuit each including a ballast choke type inverter circuit.
Further, the height 2331 is a shape made of a polycarbonate resin (Taflon URZ2502 manufactured by Idemitsu Kosan Co., Ltd.) shown in FIG. A support pin 2300 having a diameter of 25 mm was attached to the same position as the backlight device of Example 1.
Next, the surface on which the pattern shown in FIG. 34 is formed is directed to the hot cathode tube lamp side, and as shown in FIG. 22, the axes 2216F ₁ and 2216F _{2 of the} fluorescent tube bent portion are the side 2231W ₁ and the line 2231C ₁ , respectively. so as to be positioned exactly in the middle of the just middle, and the side 2231W ₂ and line 2231C ₂ with, installed on the reflecting plate made of the light diffuser plate 2231 from the reflection sheet sticking aluminum case. At this time, the distance between the center of the hot cathode tube lamp and the light incident surface of the light diffusion plate 2231 was 15.25 mm.

  Furthermore, a prism sheet (“BEFIII-10T” manufactured by Sumitomo 3M Co., Ltd.) and a diffusion sheet (manufactured by Kimoto Co., “light up 188GM3”), each corresponding to an optical sheet, on the light exit surface side of the light diffusion plate 2231 Were installed in this order to obtain a direct type backlight device. The prism sheet was installed with the longitudinal direction of the prism parallel to the straight portion of the hot cathode tube lamp.

The obtained direct type backlight device is lit under the same conditions as in Example 2, and the luminance and luminance unevenness, the transmittance corresponding to the region X and the region Y, the position directly above the emitter and the longitudinal direction of the hot cathode tube lamp The surface temperature of the light diffusing plate entrance surface at the center, the surface temperature of the light diffusing plate exit surface at the intermediate position in the length direction of the bent portion, the residual stress of the light diffusing plate, the amount of infrared rays, and the lifetime were evaluated. The transmittances of the portions corresponding to the region X and the region Y were 60% and 80%, respectively. The other results are shown in FIG.
Similarly to Example 1, a VA type liquid crystal panel or an IPS type liquid crystal panel is mounted and a lighting test for 100 hours, a warp test on a light diffusion plate during a life test, a luminance unevenness test near the electrode, a transmission of a light control unit. When the confirmation test of the heat function and the heat diffusion function was carried out, the result was the same as in Example 1.

<Example 20>
A direct type backlight device including a reflector, a fluorescent lamp, and a light diffusing plate was produced.

(20-1: reflector)
The same reflector as in Example 1-1 (1-1) was prepared.

(20-2: Hot cathode tube lamp)
A fluorescent tube made of soda lime glass having a square shape and a hot cathode tube lamp having a filament part, schematically shown in FIG. 28, were prepared. The fluorescent tube included in this hot cathode tube lamp had an outer diameter of about 15.5 mm, a glass thickness of 0.7 mm, and a glass transmittance of 90%. The length of the side 2890A1 of the fluorescent tube 2890 provided with the filament portion 2890T and the side 2890A2 parallel to the side 2890A2 (corresponding to the length of the arrow 2891A), and the length of the side 2890B perpendicular to the sides 2890A1 and 2890A2 (of the arrow 2891B) (Corresponding to the length) was 90 mm in all cases. At both ends of the fluorescent tube, electrodes having an emitter (electron emitting material) containing BaO, SrO, and CaO in a ratio of 1: 1: 1 on a tungsten coil of a triple coil were installed. In addition, a three-wavelength light emitting phosphor was formed on the inner wall surface of the fluorescent tube, and mercury and 1 kPa of argon were sealed in the fluorescent tube.

(20-3: Light diffusion plate)
A light diffusion plate 2831 schematically shown in FIG. 29 was formed in the same manner as (1-3) of Example 1 except that the mold was changed to the following predetermined shape. The resulting light diffusing plate 2831, thickness 2 mm, the width (side 2831W ₁ and 2831W ₂ direction in FIG. 29) 573mm × length (side 2831L direction in FIG. 29) 1018mm rectangular plate-shaped, its It had a predetermined uneven structure on both sides.

  On one surface of the light diffusion plate 2831 (used as an exit surface), a triangular linear prism (triangular prism) having a cross section with an apex angle of 100 ° is formed with a pitch of 70 μm and no gap in a flat portion ( The triangular base corner portions adjacent to each other are in contact with each other so that there is no flat portion (that is, the triangular base corner portions adjacent to each other are in contact with each other).

On the other hand, on the other surface (used as an incident surface) of the light diffusing plate 2831, a band-shaped region 2832 is provided along the axes 2892A1 and 2892A2 of the sides 2890A1 and 2890A2 of the hot cathode tube lamp 2890. Region 2832, a side 2831W ₁ side edge 2832B1, the distance between the axis 2892A2 (arrow 2833W1), and a side 2831W ₂ side edges 2832B2, the distance between the axis 2892A1 (arrow 2833W2) are both set to 15 mm. Since the distance 2891G between the shafts 2892A1 and 2892A2 is 20 mm, the width of the region 2832 is 50 mm.

Of the incident surface of the light diffusing plate 2831, a region other than the region 2832 is provided with the same pattern as that in the region from the line 631 </ b> C to the side 631 </ b> W ₂ described in the first embodiment and FIG. 6. On the other hand, in the region 2832, as described in Example 1 and 6, the pattern in the region of from the line 631C to the side 631W _2, the same angle with both prism pattern in a region of from the line 631C to the side 631W ₁ A pattern having a shape in which a square pyramid composed of slopes having an inclined surface was inverted was provided. That is, in a mold for molding the surface, in the region corresponding to the region 2832, a side 2831L direction parallel digging the same groove as that provided in the region line 631C～631W ₂ in FIG. 6, in addition to the direction parallel to the sides 2831W ₁ and 2831W ₂ with a quadrangular pyramid formed by digging the same groove as that provided in the region line 631C～631W ₁ in FIG. 6, the transfer shape this, area 2832 Formed.

(20-4: Assembly of backlight device)
Twenty-seven hot cathode tube lamps obtained in (20-2) above were attached to the reflector in the form shown in FIG. In each of the three rows of hot cathode tube lamps, the axis (2892A1) of the fluorescent tube portion 2890A1 and the axis (2892A2) of the 2890A2 were aligned. On the other hand, in each of the five or four hot-cathode tube lamp rows, the axes (2892B) of the fluorescent tube portion 2890B were aligned and aligned with the axes of other adjacent rows. A gap 2891G between the axis 2892A1 and the axis 2892A2 in another adjacent row was set to 20 mm.

  Each hot-cathode tube lamp was fixed with an appropriate support (not shown), the distance from the reflector to the axis of the hot-cathode tube lamp was 9.75 mm, and an operating circuit was connected. This operation circuit (corresponding to a ballast) includes a lighting circuit and a preheating circuit each including a ballast choke type inverter circuit.

Furthermore, the height 2331 is a shape manufactured by using a polycarbonate resin (Taflon URZ2502 manufactured by Idemitsu Kosan Co., Ltd.) and a hemisphere having a diameter of 1 mm on a truncated cone shape having a bottom diameter 2332 of 2 mm and an upper diameter 2333 of 1 mm as shown in FIG. A support pin 2300 having a diameter of 25 mm was attached to the center of each hot cathode tube lamp as shown in FIG.
Next, with the incident surface facing the hot cathode tube lamp side, as described above with reference to FIG. 29, the light diffusing plate 2831 is attached to the reflecting sheet so that the axes 2892A1 and 2892A2 are aligned with the region 2832. It installed on the reflector which consists of cases. At this time, the distance between the center of the hot cathode tube lamp and the light incident surface of the light diffusion plate 2831 was 15.25 mm.

  Further, a prism sheet (manufactured by Sumitomo 3M, “BEFIII-10T”), and a diffusion sheet (manufactured by Kimoto, “Light-Up 188GM3”), each corresponding to an optical sheet, on the light exit surface side of the light diffusion plate 2831 Were installed in this order to obtain a direct type backlight device. The prism sheet was installed with the longitudinal direction of the prism parallel to the straight portion of the hot cathode tube lamp.

The obtained direct type backlight device is lit under the same conditions as in Example 2, and the luminance and luminance unevenness, the transmittance corresponding to the region X and the region Y, the position directly above the emitter and the longitudinal direction of the hot cathode tube lamp The surface temperature of the light diffusing plate entrance surface at the center, the surface temperature of the light diffusing plate exit surface at the intermediate position in the length direction of the bent portion, the residual stress of the light diffusing plate, the amount of infrared rays, and the lifetime were evaluated. The transmittances of the portions corresponding to the region X and the region Y were 60% and 80%, respectively. The other results are shown in FIG.
Similarly to Example 1, a VA type liquid crystal panel or an IPS type liquid crystal panel is mounted and a lighting test for 100 hours, a warp test on a light diffusion plate during a life test, a luminance unevenness test near the electrode, a transmission of a light control unit. When the confirmation test of the heat function and the heat diffusion function was carried out, the result was the same as in Example 1.

<Example 21>
A direct type backlight device including a reflector, a fluorescent lamp, and a light diffusing plate was produced.

(21-1: reflector)
A reflector was prepared in the same manner as (1-1) in Example 1 except that the inner length was 1200 m and the width was 573 mm.

(21-2: Hot cathode tube lamp)
Five types of hot-cathode tube lamps having a fluorescent tube made of soda-lime glass having a square shape and a filament portion schematically shown in FIG. 30 were prepared. The fluorescent tube included in this hot cathode tube lamp had an outer diameter of about 15.5 mm, a glass thickness of 0.7 mm, and a glass transmittance of 90%. The lengths 3091A1 to 3091A5 of one side of the square fluorescent tubes 3090S1 to 3090S5 were 60 mm, 180 mm, 300 mm, 420 mm, and 540 mm, respectively. At both ends of the fluorescent tube, electrodes having an emitter (electron emitting material) containing BaO, SrO, and CaO in a ratio of 1: 1: 1 on a tungsten coil of a triple coil were installed. Further, a three-wavelength light emitting phosphor is formed on the inner wall surface of the fluorescent tube, and mercury and 0.5 kPa of argon are sealed in the fluorescent tube.

(21-3: Light diffusing plate)
A light diffusing plate was molded in the same manner as (1-3) in Example 1 except that the mold was changed to change the dimensions and the shape of the surface irregularities. The obtained light diffusion plate was a rectangular flat plate having a thickness of 2 mm, a width of 700 mm, and a length of 1200 mm, and had a predetermined uneven structure on both sides thereof.

  On one surface of the light diffusing plate (used as an output surface), a pattern having a shape in which a square pyramid constituted by slopes orthogonal to the pattern of the output surface of the light diffusing plate of Example 1 was inverted was provided. That is, in the mold for molding this surface, a triangular linear prism (triangular prism) having a cross section with an apex angle of 100 ° has a pitch of 70 μm and there is no flat part gap (so that there is no flat part). In other words, a groove is formed in such a manner that the triangular base corner portions adjacent to each other are in contact with each other in the length direction of the light diffusion plate, and further, a similar groove is also formed in the width direction to form a square. A shape obtained by forming a weight and transferring the weight was formed on the exit surface of the light diffusion plate of this example.

  On the other surface (used as the incident surface) of the light diffusing plate, a pattern having a shape in which a quadrangular pyramid composed of inclined surfaces in which triangular prism patterns having the shapes and distributions described in detail below are perpendicular to each other is inverted is provided. That is, in the mold for molding this surface, a square pyramid was formed by digging grooves in the length direction and width direction of the light diffusion plate to form a triangular prism described in detail below, and this was transferred. The shape was formed on the exit surface of the light diffusion plate of this example.

  In the length direction of the incident surface of the light diffusing plate, when the backlight device is configured, the positions where the axes 3091Q1 to 3091Q10 of the hot cathode tube lamp shown in FIG. 60 mm) was divided into 17 zones, and triangular prisms were distributed. The specific method of dividing the zones and the arrangement of the triangular prisms are the same as those performed between the axes 616PA to 616PB in FIG. 8, but the range of the zones A to Q and the mixing ratio are as shown in FIG. Changed to The pitch of the triangular prism was set to 65.2 μm only in the zone Q, but in the other zones A to P, the pitch was set to 70 μm as in the first embodiment.

  In the width direction of the incident surface of the light diffusing plate, the position where the axes 3091R1 to 3091R20 of the hot cathode tube lamp shown in FIG. ) Were divided into 17 zones as in the length direction, and triangular prisms were distributed.

(21-4: Assembly of backlight device)
Two of the hot cathode tube lamps 3090S1 to 3090S5 obtained in (21-2) above were attached to the reflector in the manner shown in FIG. The distance between the axes 3091Q1 to 3091Q10 and the distance between the axes 3091R1 to 3091R20 of the hot cathode tube lamp were both 60 mm. For each of adjacent 3090S1 to 3090S5, each of the shafts 3091Q1 to 3091Q10 in the longitudinal direction of the apparatus was aligned on a straight line.

  Each hot-cathode tube lamp was fixed with an appropriate support (not shown), the distance from the reflector to the axis of the hot-cathode tube lamp was 9.75 mm, and an operating circuit was connected. This operation circuit (corresponding to a ballast) includes a lighting circuit and a preheating circuit each including a ballast choke type inverter circuit.

Furthermore, the height 2331 is a shape manufactured by using a polycarbonate resin (Taflon URZ2502 manufactured by Idemitsu Kosan Co., Ltd.) and a hemisphere having a diameter of 1 mm on a truncated cone shape having a bottom diameter 2332 of 2 mm and an upper diameter 2333 of 1 mm as shown in FIG. As shown in FIG. 23, a support pin 2300 having a diameter of 25 mm was attached at a position corresponding to the intersection of one of the lines 3071H1 to 3071H7 and one of the lines 3071J1 to 3071J12. Here, the lines 3071H1 to 3071H7 are parallel to the axes 3091Q1 to 3091Q10, and the lines 3071J1 to 3071J12 are parallel to the axes 3091R1 to 3091R20. Each of the lines 3071H1 to 3071H7 is located in the middle of the nearest two of the axes 3091Q1 to 3091Q10, and each of the lines 3071J1 to 3071J12 is located in the middle of the nearest two of the axes 3091R1 to 3091R20.
Next, with the incident surface facing the hot-cathode tube lamp side, as described above with reference to FIG. 30, the shafts 3091Q1 to 3091Q10 and the shafts 3091R1 to 3091R20 correspond to predetermined positions of the light diffusion plate. The light diffusing plate was placed on a reflecting plate made of an aluminum case with a reflecting sheet attached. At this time, the distance between the center of the hot cathode tube lamp and the light incident surface of the light diffusion plate 2831 was 15.25 mm.

  Furthermore, a prism sheet ("BEFIII-10T" manufactured by Sumitomo 3M Limited) and a diffusion sheet ("Light-Up 188GM3" manufactured by Kimoto Co., Ltd.), each corresponding to an optical sheet, are provided on the light exit surface side of the light diffusing plate. This was installed in this order to obtain a direct type backlight device. The prism sheet was installed with the longitudinal direction of the prism parallel to the straight portion of the hot cathode tube lamp.

The obtained direct type backlight device is lit under the same conditions as in Example 2, and the luminance and luminance unevenness, the transmittance corresponding to the region X and the region Y, the position directly above the emitter and the longitudinal direction of the hot cathode tube lamp The surface temperature of the light diffusing plate entrance surface at the center, the surface temperature of the light diffusing plate exit surface at the intermediate position in the length direction of the bent portion, the residual stress of the light diffusing plate, the amount of infrared rays, and the lifetime were evaluated. The transmittances of the portions corresponding to the region X and the region Y were 60% and 80%, respectively. The other results are shown in FIG.
Similarly to Example 1, a VA type liquid crystal panel or an IPS type liquid crystal panel is mounted and a lighting test for 100 hours, a warp test on a light diffusion plate during a life test, a luminance unevenness test near the electrode, a transmission of a light control unit. When the confirmation test of the heat function and the heat diffusion function was carried out, the result was the same as in Example 1.

<Example 22>
A direct type backlight device including a reflector, a fluorescent lamp, and a light diffusing plate was produced.

(22-1: reflector)
A reflector was prepared in the same manner as (1-1) in Example 1 except that the inner length was 1018 m and the width was 180 mm.

(22-2: Hot cathode tube lamp)
A hot-cathode tube lamp having a fluorescent tube made of soda-lime glass and a filament portion, which is schematically shown in FIG. 31, and has a U-shape, was prepared. The fluorescent tube 3116 included in this hot cathode tube lamp had an outer diameter of about 15.5 mm, a glass thickness of 0.7 mm, and a glass transmittance of 90%. The length (arrow 3116AL) of the long portion 3116L of the fluorescent tube 3116 was 958 mm, and the length (arrow 3116AS) of the short portion 3116S was 45 mm. At both ends of the fluorescent tube, electrodes having an emitter (electron emitting material) containing BaO, SrO, and CaO in a ratio of 1: 1: 1 on a tungsten coil of a triple coil were installed. In addition, a three-wavelength light emitting phosphor was formed on the inner wall surface of the fluorescent tube, and mercury and 1 kPa of argon were sealed in the fluorescent tube.

(22-3: Light diffusion plate)
A light diffusing plate 3131 schematically shown in FIG. 32 was formed in the same manner as (1-3) in Example 1 except that the mold was changed to the following predetermined shape. The obtained light diffusing plate 3131 is a rectangular flat plate having a thickness of 2 mm, a width (directions of sides 3131W ₁ and 3131W ₂ in FIG. 31) 300 mm × length (direction of sides 3131L in FIG. 31) 1200 mm, It had a predetermined uneven structure on both sides.

  On one surface of the light diffusion plate 3131 (used as an exit surface), a triangular linear prism (triangular prism) having a cross section with an apex angle of 100 ° is formed with a pitch of 70 μm and no gap in a flat portion ( The triangular base corner portions adjacent to each other are in contact with each other so that no flat portion is present (that is, the triangular base corner portions adjacent to each other are in contact with each other).

On the other hand, in the region surrounded by the lines 3131A and 3131B on the other surface (used as the incident surface) of the light diffusion plate 3131, a portion corresponding to the axis 3116G of the two hot cathode tube lamps 3116 is the axis in the first embodiment. Like 616PA-616PB, it was divided into 17 types of zones, and prism-shaped convex portions having a triangular cross section with apex angles of 140 ° to 170 ° were provided in each zone at a mixing ratio shown in FIG. On the other hand, in a region between the sides 3131W _{1 to} 3131A and a region between the sides 3131W _{2 to} 3131B, triangular linear prisms (triangular prisms) having a vertical angle of 80 ° are provided at a pitch of 70 μm and are flat portions. without gaps (as no flat portion, i.e., in contact said triangular base angle portions adjacent to each other), and substantially parallel to the side 3131W ₁ and 3131W _2.

(22-4: Assembly of backlight device)
The hot-cathode tube lamp 3116 obtained in (22-2) was attached to the reflector in the form shown in FIG. The interval between the shafts 3116G of the hot cathode tube lamp was 90 mm. Further, the distance indicated by the arrow 3116AE in FIG.

  The distance from the reflector to the axis of the hot cathode tube lamp was 9.75 mm, the vicinity of the electrode was fixed with a silicone sealant, and the operation circuit was connected. This operation circuit (corresponding to a ballast) includes a lighting circuit and a preheating circuit each including a ballast choke type inverter circuit.

Further, the height 2331 is a shape made of a polycarbonate resin (Taflon URZ2502 manufactured by Idemitsu Kosan Co., Ltd.) shown in FIG. A support pin 2300 having a diameter of 25 mm was appropriately attached.
Next, with the incident surface facing the hot-cathode tube lamp side, as described above with reference to FIG. 32, the light diffusing plate is attached to the reflecting sheet so that the shaft 3116G corresponds to a predetermined position of the light diffusing plate. It was installed on a reflector made of an aluminum case. At this time, the distance between the center of the hot cathode tube lamp and the light incident surface of the light diffusion plate 3131 was 15.25 mm.

  Furthermore, a prism sheet ("BEFIII-10T" manufactured by Sumitomo 3M Limited) and a diffusion sheet ("Light-Up 188GM3" manufactured by Kimoto Co., Ltd.), each corresponding to an optical sheet, are provided on the light exit surface side of the light diffusing plate. This was installed in this order to obtain a direct type backlight device. The prism sheet was installed with the longitudinal direction of the prism parallel to the straight portion of the hot cathode tube lamp.

The obtained direct type backlight device is lit under the same conditions as in Example 2, and the luminance and luminance unevenness, the transmittance corresponding to the region X and the region Y, the position directly above the emitter and the longitudinal direction of the hot cathode tube lamp The surface temperature of the light diffusing plate entrance surface at the center, the surface temperature of the light diffusing plate exit surface at the intermediate position in the length direction of the bent portion, the residual stress of the light diffusing plate, the amount of infrared rays, and the lifetime were evaluated. The transmittances of the portions corresponding to the region X and the region Y were 60% and 80%, respectively. The other results are shown in FIG.
Similarly to Example 1, a VA type liquid crystal panel or an IPS type liquid crystal panel is mounted and a lighting test for 100 hours, a warp test on a light diffusion plate during a life test, a luminance unevenness test near the electrode, a transmission of a light control unit. When the confirmation test of the heat function and the heat diffusion function was carried out, the result was the same as in Example 1.

<Comparative Example 1>
As a material used for manufacturing the light diffusing plate, a resin composition in which 0.8 part of fine particles made of a cross-linked polysiloxane polymer having an average particle diameter of 2 μm and ZEONOR 1420R99.2 parts are mixed, and the light diffusing plate is inserted. The emission surface is a flat plate without uneven structure and printing, and the hot cathode tube lamp has silicon dioxide particles attached to the surface of the fluorescent tube as described later, the interval between the hot cathode tube lamps is 50 mm, and the hot cathode tube lamp A light diffusing plate and a direct type backlight device were prepared in the same manner as in Example 2 except that the arrangement of the pins was as described below. A flat plate having the same material as that of the diffusion plate and having a thickness of 2 mm and having no uneven structure was produced under the same conditions as described above, and the light transmittance was measured to be 65%. Silicon dioxide was adhered to the region on the exit surface side so that the light transmittance of the glass surface was 70% over the entire length of the fluorescent tube (both bent and straight portions).
The arrangement of the hot cathode tube lamp and pins in this comparative example will be described with reference to FIG.
The six bent portions of the hot-cathode tube lamps are installed so as to be arranged on the same side, and the short side of the direct type backlight device from the center line 116F of the straight tube portion in the bent portion (side 3331W ₁ shown in FIG. 33). The distance to the side wall was 30 mm. The distances 3351A and 3351B (FIG. 33) between the centers of the straight portions of the hot cathode tube lamp were 50 mm, and the distance from the reflector to the center of the hot cathode tube lamp was 9.75 mm.
All of the positions of the support pins 2300 are intermediate positions of the axes 3316G of the two most recent fluorescent tube straight portions (that is, the same distance from both of the two most recent straight tube portions). In sides 3331W ₁ and 100mm both distance and the distance from the line 3371D to line 3371E from midline 3371D to line 3371C in the 3331W _2, the distance between the sides 3331W ₂ and line 3371G is 100mm, the sides 3331W ₂ and line 3371F the distance a 200 mm, the distance of the distance between the side 3331W ₁ and line 3371A is 100 mm, the sides 3331W ₁ and line 3371B was 200 mm. The distance 3316K between the emitter position 120A of the hot cathode tube lamp and the nearest pin is about 103 mm. The distance 3316J between the pin and the nearest pin is 100 mm.

  The obtained direct type backlight device was turned on under the same conditions as in Example 1, and the luminance and luminance unevenness, the transmittance corresponding to the regions X and Y, and the residual stress of the light diffusion plate were evaluated. The transmittances of the portions corresponding to the regions X and Y were 60% and 80%, respectively. Other results are shown in FIG.

<Comparative example 2>
Example 1 with the exception that the same resin composition as that used in Comparative Example 1 was used as the material used in the manufacture of the light diffusing plate, and the light diffusing plate was a flat plate having an uneven structure and no printing on the incident / exit surface. Similarly, a light diffusion plate and a direct type backlight device were prepared.

The obtained direct-type backlight device is turned on under the same conditions as in Example 2, and the luminance and luminance unevenness, the transmittance of the portion corresponding to the region X and the region Y, and the light at the intermediate position in the length direction of the bent portion The surface temperature of the light diffusing plate exit surface, the residual stress of the light diffusing plate, the amount of infrared rays, and the lifetime were evaluated. The transmittances of the portions corresponding to the region X and the region Y were 60% and 80%, respectively. The other results are shown in FIG.
When the same VA type liquid crystal panel as in Example 1 was mounted on this backlight and turned on for 100 hours, the display near the electrodes was disturbed. Even in the same IPS type liquid crystal panel as in Example 1, disorder occurred in 100 hours.
The surface temperature of the light diffusing plate incident surface was measured. One hour after the surface temperature reached equilibrium, the temperature immediately above the filament was 90 ° C., and 41 ° C. just above the center of the hot cathode tube lamp. After the life test, the position immediately above the filament was yellowed.

<Comparative Example 3>
A direct type backlight device was produced in the same manner as in Example 1 except that the filament current for preheating was 1200 mA and the emitter surface temperature was maintained at 1050 ° C.
About the obtained direct type backlight device, as in Example 2, the luminance and luminance unevenness, the transmittance of the portion corresponding to the region X and the region Y, the light diffusion at the position directly above the emitter and the central portion in the longitudinal direction of the hot cathode tube lamp The surface temperature of the plate incident surface, the surface temperature of the light diffusing plate exit surface at the intermediate position in the length direction of the bent portion, the residual stress of the light diffusing plate, and the amount of infrared rays were evaluated. The transmittances of the portions corresponding to the region X and the region Y were 60% and 80%, respectively. The other results are shown in FIG.

<Comparative example 4>
A direct type backlight device was produced in the same manner as in Example 1 except that the filament current for preheating was set to 0 mA. The emitter surface temperature was about 600 ° C.
About the obtained direct type backlight device, as in Example 2, the luminance and luminance unevenness, the transmittance of the portion corresponding to the region X and the region Y, the light diffusion at the position directly above the emitter and the central portion in the longitudinal direction of the hot cathode tube lamp The surface temperature of the plate incident surface, the surface temperature of the light diffusing plate exit surface at the intermediate position in the length direction of the bent portion, the residual stress of the light diffusing plate, and the amount of infrared rays were evaluated. The transmittances of the portions corresponding to the region X and the region Y were 60% and 80%, respectively. The other results are shown in FIG.

<Comparative Example 5>
As a material used for manufacturing the light diffusing plate, the same resin composition as that used in Example 7 was used, and only in the region where the hot cathode tube lamp on the exit surface of the light diffusing plate was vertically projected on the light diffusing plate, Light diffusing plate and direct type backlight device as in Example 2 except that a prism having a triangular section is formed with an apex angle of 90 ° and a pitch of 70 μm, and the longitudinal direction of which is in the axial direction of the hot cathode tube lamp. It was created.

The surface temperature of the light diffusing plate incident surface was measured. One hour after the surface temperature reached equilibrium, the temperature immediately above the filament was 90 ° C., and 41 ° C. just above the center of the hot cathode tube lamp. After the life test, the position immediately above the filament was yellowed.
The obtained direct-type backlight device is turned on under the same conditions as in Example 2, and the luminance and luminance unevenness, the transmittance of the portion corresponding to the region X and the region Y, and the light at the intermediate position in the length direction of the bent portion The surface temperature of the exit surface of the diffuser, the residual stress of the light diffuser, and the amount of infrared rays were evaluated. The transmittances of the portions corresponding to the region X and the region Y were 60% and 80%, respectively. In this comparative example, the luminance half life was 60,000 hours, but the initial luminance unevenness of 5% became 9% when 3000 hours had elapsed, and from the viewpoint of luminance unevenness, the result was a deterioration in a time shorter than the luminance half life. It became. The other results are shown in FIG.

<Comparative Example 6>
A direct type backlight device was prepared in the same manner as in Example 2 except that the emitter was not coated on the tungsten filament, and the device was turned on under the same conditions as in Example 2, and evaluation of luminance and luminance unevenness was attempted. The electrode of the hot cathode tube lamp was cut in 2 minutes, and the numerical value could not be evaluated.

1 is a perspective view schematically showing one embodiment of a direct type backlight device of the present invention. FIG. 1 is an elevational sectional view schematically showing one embodiment of a direct type backlight device of the present invention. FIG. It is a top view which shows roughly the fluorescent lamp and ballast which are used in one Embodiment of the direct type | mold backlight apparatus of this invention. FIG. 4 is a partial top view showing the fluorescent lamp shown in FIG. 3 in more detail. FIG. 7 is a partial side sectional view showing the relationship between the light diffusion plate and the fluorescent lamp shown in FIG. 6 in more detail. It is a top view which shows roughly the relationship between the light diffusing plate, fluorescent lamp, and support pin concerning one Embodiment of the direct type | mold pack light apparatus of this invention. FIG. 7 is a partial elevation sectional view showing the light diffusing plate shown in FIG. 6 in more detail. FIG. 7 is an elevational sectional view showing the structure of the surface of the light diffusing plate shown in FIG. 6 in more detail. FIG. 7 is a partial elevational sectional view showing the light diffusing plate and the fluorescent lamp shown in FIG. 6 in more detail. It is an elevational sectional view schematically showing the structure of the surface of the light diffusing plate used in Example 4 of the present application. It is an elevational fragmentary sectional view which shows roughly the structure of the surface of the light diffusing plate used in this-application Example 4. It is a top view which shows roughly the structure of the light-incidence surface of the light diffusing plate used in this-application Example 5. FIG. It is a top view which shows roughly the structure of the light-incidence surface of the light diffusing plate used in this-application Example 6 and 8. It is a top view which shows the structure of the zone 1371 of the light diffusing plate shown in FIG. 13 in detail. It is a partial top view which shows roughly the relationship between the reflecting plate used in this-application Example 7, and the fluorescent lamp. It is a partial elevation sectional view which shows roughly the relationship between the reflecting plate used in this-application Example 7 and the fluorescent lamp. It is a top view which shows roughly the structure of the light-incidence surface of the light diffusing plate used in this-application Example 9. FIG. It is a partial top view which shows roughly the fluorescent lamp used in this-application Example 10. FIG. It is a partial elevation sectional view showing roughly the fluorescent lamp used in Example 10 of the present application. It is a top view which shows roughly the structure of the light-incidence surface of the light diffusing plate used in this-application Example 11. It is a top view which shows roughly arrangement | positioning of the support pin in this-application Example 17. FIG. It is a top view which shows roughly the relationship between the light diffusing plate used in this-application Example 19 and the fluorescent lamp. It is a figure which shows the example of the support pin used for the direct type | mold backlight apparatus of this invention. It is a fragmentary top view which shows in more detail the relationship between the zone 1771 shown in FIG. 17, and a fluorescent lamp. It is a top view which shows roughly the relationship between the light diffusing plate used in this-application Example 18, the fluorescent lamp, and the support pin. FIG. 26 is a partial elevation sectional view showing the light diffusing plate shown in FIG. 25 in more detail. FIG. 26 is a partial elevational sectional view showing the light diffusing plate and the fluorescent lamp shown in FIG. 25 in more detail. It is a top view which shows roughly the relationship between the light diffusing plate and fluorescent lamp which were used in this-application Example 20. FIG. It is a top view which shows roughly the structure of the light-incidence surface of the light diffusing plate used in this-application Example 20. FIG. It is a top view which shows roughly the relationship between the light diffusing plate and fluorescent lamp which were used in this-application Example 21. It is a top view which shows roughly the relationship between the light diffusing plate and fluorescent lamp which were used in this-application Example 22. It is a top view which shows roughly the structure of the light-incidence surface of the light diffusing plate used in this-application Example 22. It is a top view which shows roughly the relationship between the light diffusing plate used in this-application comparative example 1, a fluorescent lamp, and a support pin. It is a table | surface which shows the mixing ratio of the pattern of the surface of the light diffusing plate used in this-application Example 1. FIG. It is a table | surface which shows the mixing ratio of the pattern of the surface of the light diffusing plate used in this-application Example 21. It is a table | surface which shows the conditions and result of this-application Example 1- Example 15. FIG. It is a table | surface which shows the conditions and result of this-application Example 16- Example 22 and Comparative Examples 1-6.

Claims (8)

A fluorescent lamp, a reflecting plate that reflects light from the fluorescent lamp on its surface, and direct light from the fluorescent lamp and reflected light from the surface of the reflecting plate enter from the light incident surface and exit from the light emitting surface A direct-type backlight device comprising a light diffusing plate,
The fluorescent lamp comprises a fluorescent tube and a filament portion provided at at least one end of the fluorescent tube,
The filament portion includes a filament and an emitter provided on an outer peripheral portion of the filament,
The direct type backlight device further includes a preheating circuit for preheating the emitter so that the surface temperature thereof is always maintained at 700 to 950 ° C.,
Each of the fluorescent tubes has a straight part (a) and a part (b) non-parallel to the part (a),
In the direct type backlight device, the plurality of portions (a) are arranged substantially in parallel,
On the surface region X in the surface of at least one of the light incident surface and the light emitting surface, in which the outer dimensions of the plurality of portions (a) are projected perpendicularly to the light incident surface, the normal line of the light diffusion plate A light control part (A) extending in a direction substantially parallel to the part (a) for controlling the amount of light emitted along the direction;
In the light diffusing plate, the transmittance in the normal direction of the light diffusing plate in the region X is centered on an intermediate position of the regions X adjacent to each other, and has the same width as the outer diameter of the fluorescent tube, Lower than the transmittance in the direction in which light enters from the center of the fluorescent lamp to the light diffusion plate in the region Y having the same length as the length of the portion of the region X where the light control unit (A) is provided,
The surface region Z _{1 in} the light exit surface, the surface region Z ₂ in the light incident surface, including the region obtained by projecting the outer dimension of the part (b) perpendicularly to the light diffusion plate, and the part of the fluorescent tube ( in at least one region of the surface region T ₂ of the surface of the light diffuser plate side in b), a control amount of light emitted along the normal direction of the light diffuser plate, substantially to the portion (a) A light control section (B) extending in the vertical direction is provided;
The direct-type backlight device, wherein the light control unit (A) has a heat transfer function and the light control unit (B) has a heat diffusion function. In the direct type backlight device according to claim 1,
The light diffusing plate is a direct type backlight device having a residual stress of 10 MPa or less. The direct type backlight device according to claim 1 or 2,
The light diffusing plate is an arbitrary point in the region where the electrode of the fluorescent lamp is vertically projected onto the light diffusing plate, and the non-parallel portion (b) is within the region where the non-parallel portion (b) is vertically projected onto the light diffusing plate. A direct-type backlight device in which when any two points are selected from any one point and any one point in the other region, the difference in residual stress at those points is 10 MPa or less. The direct type backlight device according to any one of claims 1 to 3,
The light control unit (A) and the light control unit (B) are direct type backlight devices further having a function of reflecting and / or refracting infrared rays. The direct type backlight device according to any one of claims 1 to 4,
Between the reflecting plate and the light diffusing plate, one or more support pins for supporting the light diffusing plate so as not to bend are provided,
A direct type backlight device in which the distance between each support pin and the emitter closest to the support pin is within 250 mm. In the direct type backlight device according to claim 5,
With two or more support pins,
A direct type backlight device in which when any one of the two or more support pins is selected, a distance between the support pin and another support pin closest to the support pin is within 200 mm. The direct type backlight device according to any one of claims 1 to 6,
The direct type backlight device in which the light emission surface is provided with an emission-side light control unit that controls the amount of emitted light. The direct type backlight device according to any one of claims 1 to 7,
A liquid crystal cell disposed on the light emitting side of the direct type backlight device,
A liquid crystal display device in which the liquid crystal cell is in a VA mode or an IPS mode.

Images