JP4899846B2 - Backlight unit and liquid crystal display device - Google Patents

Description

  The present invention relates to a backlight unit and a liquid crystal display device.

  FIG. 23 is an exploded perspective view of a conventional direct type backlight unit. The backlight unit 1 includes a lamp 2, a housing 3, optical sheets 4, and a connection member 5, and is used as a light source for a liquid crystal display device. In recent years, a liquid crystal display device using a direct type backlight unit such as a liquid crystal TV has been increasing in size, and a lamp (a cold cathode fluorescent lamp, an external electrode fluorescent lamp, or a hot cathode fluorescent lamp) 2 inserted therein. There is a tendency to lengthen. However, the outer diameter of the lamp 2 is about 2.4 [mm] to 20 [mm], but the entire length of the lamp 2 is over 600 [mm]. Therefore, when the lamp 2 is housed in the housing 3, deflection occurs at an intermediate portion between both ends thereof, which causes luminance unevenness as the entire backlight unit 1. When the deflection of the lamp 2 is large, a load is applied to the glass bulb 7 of the lamp 2 and the lamp 2 is damaged.

As means for preventing this, as shown in FIG. 24, a backlight unit 1 is disclosed in which a lamp holding member 6 that supports the lamp 2 is provided at an intermediate portion between both ends of the lamp 2.
JP 2001-210126 A

  However, even if the lamp holding member 6 is provided, depending on the position where the lamp holding member 6 is provided, the deflection of the lamp 2 cannot be sufficiently eliminated, and the distance between the lamp 2 and the optical sheets 4 in the longitudinal direction of the lamp 2 varies. This causes uneven brightness in the backlight unit 1 as a whole. Depending on the position where the lamp holding member 6 is provided, a large load is applied to the glass bulb 7 due to the force of the lamp holding member 6 that supports the lamp 2. For this reason, the lamp holding member 6 may cause damage to the glass bulb 7. Furthermore, when the lamp 2 is a cold cathode fluorescent lamp, since the connecting member 5 holds only the lead wire 8, a load is applied to the sealing portion of the glass bulb 7 to which the lead wire 8 is sealed, There is a possibility that the sealing portion of the glass bulb 7 is damaged, or the enclosed matter inside the lamp 2 leaks along with the damage.

  In order to solve the above problems, the present invention has an object to provide a backlight unit that eliminates lamp deflection in the backlight unit, suppresses luminance unevenness as the backlight unit, and prevents damage to the lamp. To do.

In order to solve the above-described problems, a backlight unit according to the present invention includes a housing having an opening for extracting light, a lamp housed in the housing, and the lamp connected to a lighting circuit. And the glass bulb of the lamp is made of glass having an alkali metal content of 3 [mol%] to 20 [mol%].
The backlight unit according to the present invention is characterized in that a lamp holding member is provided in the vicinity of the air point between both ends of the lamp. Here, “near the airy point” means a position within 5% of the length between the airy point and the airy point in the longitudinal direction of the lamp.

  Further, in the backlight unit according to the present invention, the air point is separated by 0.2113 L [mm] from both ends of the glass bulb having the total length L [mm] of the lamp toward the center in the longitudinal direction of the lamp. Preferably it is a position. In this case, “near the airy point” means a position within L (1-2 × 0.2113) × 0.05 [mm] from the airy point in the longitudinal direction of the lamp.

  In the backlight unit according to the present invention, it is preferable that the lamp holding member is provided with an optical sheet supporting member that supports optical sheets positioned in front of the housing.

  In the backlight unit according to the present invention, the lamp has a flat cross section cut at least perpendicularly to the tube axis of the lamp of the light extraction portion, and is cut perpendicularly to the tube axis of the lamp. It is preferable that the cross section of the flat portion is parallel to the optical sheets positioned on the front surface of the casing.

  The liquid crystal display device according to the present invention includes the backlight unit.

  Since the backlight unit according to the present invention can eliminate the lamp deflection in the backlight unit, it is possible to eliminate the luminance unevenness as the backlight unit and to prevent the lamp from being damaged. In addition, since the liquid crystal display device according to the present invention can eliminate luminance unevenness that occurs in the entire backlight unit, a liquid crystal display device with improved image quality can be provided.

(First embodiment)
FIG. 1 is an exploded perspective view of the backlight unit 100 according to the first embodiment of the present invention. FIG. 2 is a sectional view taken along the line AA ′, and FIG. 3 is a plan view thereof (excluding the optical sheets 4 and the cover 113). The backlight unit 100 according to the first embodiment (hereinafter simply referred to as “backlight 100”) is a direct type, and is housed in a rectangular parallelepiped housing 3 having an opening on one surface. A plurality of lamps 2, a lamp holding member 101 for holding the lamp 2, a pair of connecting members 102 for electrically connecting the lamp 2 to a lighting circuit (not shown), and a housing 3 And an optical sheet 4 covering the opening.

<Description of the housing>
The housing 3 is made of, for example, polyethylene terephthalate (PET) resin, and a reflective surface 103 is formed on the inner surface thereof by depositing a metal such as silver. In addition, as a material of the housing | casing 3, you may comprise with materials other than resin, for example, metal materials, such as aluminum and a cold rolling material (for example, SPCC). In addition to the metal vapor-deposited film, the reflective surface 103 on the inner surface is, for example, a material obtained by sticking a reflective sheet whose reflectance is increased by adding calcium carbonate, titanium dioxide or the like to polyethylene terephthalate (PET) resin. May be.

<Description of lamp holding member>
In a state where the lamp 2 is housed in the housing 3, the lamp holding member 101 is provided near the airy point between the both ends of the lamp 2 (the intermediate point of the lamp holding member 101 in the longitudinal direction of the lamp 2). Yes. As shown in FIG. 2, when the length of the lamp 2 in the longitudinal direction is L ₁ [mm], the “airy point” is 0. 0 mm from both ends of the lamp 2 toward the center of the lamp 2 in the longitudinal direction. It is preferable that the position is 2113L ₁ [mm] away. Specifically, as will be described later, when the entire length of the lamp 2 is 760 [mm], the lamp 2 is 161 [mm] from both ends (both ends of the external lead wire 8b) toward the center in the longitudinal direction. It is held by the lamp holding member 101 at a distant position. It should be noted that it is not necessary that the position is just 161 [mm] away from the both ends of the lamp 2, and it may be in the vicinity of the airy point. Here, “near the airy point” means a position within L ₁ (1-2 × 0.2113) × 0.05 [mm] from the airy point in the longitudinal direction of the lamp.

  A perspective view of the lamp holding member 101 is shown in FIG. As shown in FIG. 4, the lamp holding member 101 is formed of an insulator such as an epoxy resin, and includes a lamp holding portion 101a, a leg portion 101b, and an optical sheet support member 101c. The material of the lamp holding member 101 is not limited to the above. For example, polycarbonate resin, polyacetal resin, fluororesin, etc. may be used.

  The lamp holding part 101a is composed of a pair of holding pieces that are arc-shaped outward so that the glass bulb 7 of the lamp 2 can be held. Note that the shape of the lamp holding portion 101a is flat when the lamp 2 is a lamp having a flat cross section (hereinafter simply referred to as “flat lamp”) cut at least perpendicular to the tube axis in the light extraction portion. It is preferable to have a shape that follows the cross-sectional shape of the shape. When a plurality of flat lamps are incorporated in the backlight unit 100, if the circumferential direction of each flat lamp varies, the backlight unit 100 as a whole may have uneven brightness. As a method for preventing this, it is preferable that the circumferential direction of the flat lamps can be arbitrarily fixed so that the circumferential directions of the respective flat lamps are aligned, and the unevenness of luminance can be eliminated by the optical sheets 4. In particular, when the major axis of the flat portion of the cross section cut perpendicular to the tube axis is substantially parallel to the optical sheets positioned on the front surface of the housing 3, the luminance unevenness of the backlight unit 100 as a whole is reduced. More can be prevented.

  The leg portion 101 b connects the lamp holding portion 101 a and the optical sheet support member 101 c, and the bottom surface thereof is fixed to the housing 3. The optical sheet support member 101c is provided between the lamp holding portions 101a and plays a role of supporting the optical sheets 4 arranged on the front surface of the opening of the housing.

  As shown in FIG. 2, since the lamp holding member 101 is provided at the air point in the lamp 2, the optical sheet support member 101 c is also provided at the same position as the lamp holding portion 101 a in the longitudinal direction of the lamp 2. It will be. Since the length of the optical sheet 4 in the longitudinal direction is substantially the same as the length of the lamp 2 in the longitudinal direction, the optical sheet support member 101 c is provided at an air point in the optical sheet 4. . That is, since the optical sheet supporting member 101c supports the optical sheet 4 at the airy point where the bending in the longitudinal direction of the optical sheet 4 is minimized, the bending of the optical sheet 4 is also eliminated. Can do.

  The configuration of the lamp holding member 101 is not limited to the above configuration. For example, as shown in FIG. 5, the lamp holding members 6 that hold the lamps 2 at a time are arranged in a staggered manner within a range of 5% or less of the length between the airy points in the longitudinal direction of the lamps 2. It may be what you did. In this case, the positions of the lamps 2 in the longitudinal direction of the lamps 2 in the lamp holding members 6 are not the same in each of the lamps 2, so that the positions where the light flux loss due to the lamp holding members 6 occurs can be dispersed. As a result, the luminance unevenness can be reduced.

<Explanation of lamp>
As shown in FIG. 2, the lamp 2 is a cold cathode fluorescent lamp composed of a glass bulb 7, an electrode 105 and a lead wire 8.

  The glass bulb 7 is made of, for example, borosilicate glass and has a substantially circular cross section cut perpendicular to the tube axis. The overall length is 750 [mm], the outer diameter is 4 [mm], and the inner diameter is 3 [ mm] and a thickness of 0.5 [mm], and lead wires 8 are sealed at both ends thereof.

The glass material of the glass bulb 7 is not limited to the above configuration. For example, soda glass, lead glass, lead-free glass, or the like may be used. When soda glass, lead glass, or lead-free glass is used, the dark startability can be improved. That is, the glass as described above contains a lot of alkali metal oxides typified by sodium oxide (Na ₂ O). For example, in the case of sodium oxide, the sodium (Na) component is the inner surface of the glass bulb 7 over time. To elute. This is because sodium has a low electronegativity, so that it is considered that sodium eluted at the inner end of the glass bulb 7 (where no protective film is formed) contributes to the improvement of the dark startability.

  In particular, in the external electrode type fluorescent lamp 301 in which the external electrode 303 as used in the backlight unit 300 according to the third embodiment of the present invention to be described later is formed so as to cover the outer peripheral surface of the end portion of the glass bulb 7, the glass bulb As for the content rate of the alkali metal oxide in the glass material of 7, 3 [mol%] or more and 20 [mol%] or less are preferable.

  For example, when the alkali metal oxide is sodium oxide, the content is preferably 5 [mol%] or more and 20 [mol%] or less. If it is less than 5 [mol%], the probability that the dark start time will exceed 1 [second] increases (in other words, if it is 5 [mol%] or more, the probability that the dark start time will be within 1 [second] is high. When the amount exceeds 20 [mol%], the glass bulb 7 becomes black (brown) or whitens due to long-term use, resulting in a decrease in luminance, and the strength of the glass bulb 7 is reduced. This is because.

  In consideration of protection of the natural environment, it is preferable to use lead-free glass. However, lead-free glass may contain lead as an impurity in the manufacturing process. Therefore, glass containing lead at an impurity level of 0.1 [wt%] or less is also defined as lead-free glass.

  Moreover, although the lamp | ramp 2 shown in FIGS. 1-3 uses the glass bulb | ball 7 whose cross section cut | disconnected perpendicularly with respect to the tube axis | shaft is substantially circular shape, for example with respect to the tube axis | shaft in the light extraction part A flat type lamp using a glass bulb having a flat cross section cut vertically may be used. Here, the “light extraction part” refers to a part of the electrode 105 that is sandwiched between tips on the center part side in the longitudinal direction of the lamp 2. Further, the “flat shape” indicates a substantially elliptical shape, a track shape, a rounded corner shape, or the like. As an example, FIG. 6A is a cross-sectional view including the tube axis of the lamp 106 having a substantially elliptical cross section cut perpendicular to the tube axis in the light extraction portion, and FIG. FIG. 6C is a sectional view taken along line CC ′ of FIG. For example, when the outer diameter of a portion having a substantially circular cross section cut perpendicular to the tube axis of the glass bulb 107 is 5.0 [mm] and the inner diameter is 4.0 [mm], The section having a substantially oval cross section cut vertically has a short outer diameter So of 4.0 [mm], a short inner diameter Si of 3.0 [mm], a long outer diameter Wo of 5.8 [mm], and a long inner diameter. Wi is 4.8 [mm]. The portion of the ramp 106 having a flat cross section cut perpendicular to the tube axis has a substantially circular cross section having a tube outer diameter similar to the short outer diameter of the cross section cut perpendicular to the tube axis. It is possible to suppress the excessive increase in the coldest spot temperature by increasing the peripheral surface area as compared with the lamp 2. Further, the short inner diameter of the cross section cut perpendicularly to the tube axis in the lamp 106 is shorter than that of the substantially circular lamp 2 in the cross section cut perpendicular to the tube axis having the same tube inner diameter as the long inner diameter. Therefore, the distance from the center of the positive column plasma space to the inner wall of the tube can be kept substantially short. For this reason, even if the lamp current is made larger than the conventional one, it is possible to make it difficult to lower the light emission efficiency.

  A glass bulb having a flat cross-section cut perpendicularly to the tube axis over its entire length may be used. As an example, FIG. 7A shows a cross-sectional view including the tube axis of the lamp 108 having an elliptical cross section cut perpendicularly to the tube axis over the entire length, and FIG. 7B shows a DD ′ cross-sectional view thereof. The EE ′ cross-sectional view is shown in FIG.

A phosphor layer 110 is formed on the inner surface of the glass bulb 109. The phosphor layer 110 includes, for example, a red phosphor (Y ₂ O ₃ : Eu ³⁺ ), a green phosphor (LaPO ₄ : Ce ³⁺ , Tb ³⁺ ), and a blue phosphor (BaMg ₂ Al ₁₆ O ₂₇ : Eu). ²⁺ ). A protective film (not shown) of a metal oxide such as yttrium oxide (Y ₂ O ₃ ) may be provided between the inner surface of the glass bulb 109 and the phosphor layer 110. Further, inside the glass bulb 109, for example, about 2 [mg] mercury and a neon / argon mixed gas (Ne95 [%] + Ar5 [%] of about 8 [kPa] (20 [° C.]) as a rare gas. ]) Is enclosed.

  The electrode 105 is a bottomed cylindrical hollow electrode made of, for example, nickel (Ni). The electrode 105 is not limited to nickel, and may be made of, for example, niobium (Nb), tantalum (Ta), or molybdenum (Mo).

  For example, the electrode 105 has an overall length of 5.2 [mm], an outer diameter of 2.7 [mm], an inner diameter of 2.3 [mm], and a wall thickness of 0.2 [mm].

  The lead wire 8 is composed of, for example, a connection between an internal lead wire 8a made of tungsten (W) and an external lead wire 8b made of nickel (Ni) that easily adheres to solder or the like. The internal lead wire 8a and the external lead wire The joint surface with 8b is substantially flush with the outer surface of the glass bulb 7. That is, the internal lead wire 8 a is located inside the outer surface of the glass bulb 7, and the external lead wire 8 b is located outside the outer surface of the glass bulb 7.

  The internal lead wire 8a has a substantially circular cross section cut perpendicularly to the line axis, and has a total length of 3 [mm] and a wire diameter of 1.0 [mm]. The internal lead wire 8 a has an end portion on the external lead wire 8 b side sealed to the sealing portion of the glass bulb 7, and an end portion on the opposite side to the external lead wire 8 b side is approximately at the center of the outer surface of the bottom portion of the electrode 105. It is joined.

  The external lead wire 8b has a substantially circular cross section cut perpendicularly to the line axis, and has a total length of 5 [mm] and a linear shape of 0.8 [mm]. The external lead wire 8b has an end portion on the electrode 105 side joined to an end portion of the internal lead wire 8a on the external lead wire 8b side.

  The configuration of the lead wire 8 is not limited to the above configuration. For example, the internal lead wire 8a and the external lead wire 8b are not separated and may be the same configuration.

<Description of connecting member>
The connection members 102 corresponding to one lamp 2 are disposed inside the housing 3 and at both ends in the longitudinal direction of the housing 3 (x direction in FIG. 2). The pair of connecting members 102 are arranged in a number corresponding to the number of the lamps 2 with a predetermined interval in the arrangement direction of the plurality of lamps 2, that is, the short direction. As shown in FIG. 2, each connecting member 102 is composed of a power supply lead wire 102 a inserted from the outside to the inside at the bottom of the housing 3, and is electrically connected to the lead wire 8 of the lamp 2 by solder 111. ing.

  As shown in FIG. 2, from the viewpoint of safety, the power supply lead wire 102 a is preferably covered with an insulating coating 102 b except for a joint portion with the lead wire 8. Further, it is preferable that the joint portion between the connecting member 102 and the lead wire 8 is also covered with an insulating rubber cap (not shown).

  Note that the configuration of the connection member 102 is not limited to the configuration including the power feed lead wire 102a as described above. As an example, another connecting member 112 may be used as shown in FIG.

<Description of another connecting member>
Another connecting member 112 is formed by bending a plate material such as stainless steel or phosphor bronze into a substantially U shape. For example, the bottom surface of the connection member 112 is connected to a power supply lead wire 102a, and is connected to a lighting circuit (not shown) via the power supply lead wire 102a. As shown in FIG. 8, the connection member 112 includes a U-shaped portion 112 a that is directly connected to the lamp 2 and a leg portion 112 b that is fixed to the housing 3. The U-shaped portion 112a has a U-shape having an opening in the upward direction, and the lead wire 8 of the lamp 2 can be inserted into a groove portion 112c formed by the U-shape. Further, the upper end of the U-shaped portion 112a is bent outward so that the lead wire 8 can be easily inserted.

The height M ₁ of the groove 112c is 8 [mm]. The height M ₁ of the groove 112c is a vertical distance between the upper end and the lower end inside the groove 112c as shown in FIG. The width N _{1 of the} groove 112c is 0.5 [mm]. N ₁ is not limited to the above dimensions, but the pinch strength is such that the connecting member 112 has a pinching strength that allows contact with the lead wire 8 and does not prevent the lamp holding member 101 from supporting the lamp 2. What is necessary is just to have intensity | strength. The depth P _{1 of the} groove 112c is 5 [mm]. M ₁ and P ₁ are not limited to the above dimensions.

  The connecting member 112 is fixed to the housing 3 by, for example, a method of inserting a screw into the screw hole 112d of the leg 112b and screwing it. Note that the leg 112b may be formed of an insulating member such as resin. In this case, the U-shaped portion 112a needs to be connected to a lighting circuit (not shown) through the power supply lead wire 102a and the like.

  In the case of the connecting member 112, the lamp 2 and the lighting circuit can be electrically connected by simply fitting the lead wire 8 of the lamp 2 into the groove 112c. Becomes unnecessary, and the assembly process of the backlight unit 100 can be simplified.

<Description of cover>
The cover 113 divides the connection member 102 and the space inside the housing 3, and is made of, for example, polycarbonate (PC) resin. The cover 113 keeps the periphery of the end of the lamp 2 and at least the surface on the housing 3 side. Is made highly reflective to reduce a decrease in luminance at the end of the lamp 2.

<Description of optical sheets>
As shown in FIG. 1, the optical sheet 4 includes a diffusion plate 114, a diffusion sheet 115, and a lens sheet 116. The diffusion plate 114 is a plate-like body made of, for example, polymethyl methacrylate (PMMA) resin, and is disposed so as to close the opening of the housing 3. The diffusion sheet 115 is made of, for example, a polyester resin. The lens sheet 116 is, for example, a laminate of an acrylic resin and a polyester resin. These optical sheets 4 are arranged so as to be sequentially superimposed on the diffusion plate.

<Summary>
Since the backlight unit 100 according to the first embodiment of the present invention can eliminate the deflection of the lamp 2 in the backlight unit 100 with the above configuration, the luminance unevenness as the backlight unit 100 can be eliminated. And damage to the lamp 2 can be prevented. In order to eliminate the uneven brightness, it is preferable that the deflection of the lamp 2 is suppressed to 5 [mm] or less.

  In particular, when the lamp 2 is connected to the lighting circuit by the connecting member 102, the lamp 2 is held only by the lamp holding member 101 in the vicinity of the airy point no matter which direction the backlight unit 100 is tilted. Since the deflection of the lamp 2 can be eliminated when the backlight unit 100 is tilted in any direction, the luminance unevenness as the backlight unit 100 can be eliminated, and the lamp 2 can be prevented from being damaged. Can do.

  Further, when the lamp 2 is connected to the lighting circuit by the connecting member 112, the deflection of the lamp 2 is eliminated when the backlight unit 100 is arranged so that the x direction on the paper surface of FIG. Therefore, the uneven brightness of the backlight unit 100 can be eliminated, and damage to the lamp 2 can be prevented.

  In addition, the glass bulb 7 of the lamp 2 has a weaker mechanical strength than a hard glass such as borosilicate glass, and a soft glass such as soda glass or lead-free glass that tends to bend or break when it is lengthened. Even when the lamp is used, the deflection of the lamp 2 can be eliminated, so that the luminance unevenness as the backlight unit 100 can be eliminated, and the lamp 2 can be prevented from being damaged.

(Second Embodiment)
FIG. 9 shows an exploded perspective view of a backlight unit according to the second embodiment of the present invention. FIG. 10 is a sectional view taken along line FF ′, and FIG. 11 is a plan view (excluding the optical sheets 4 and the cover 113). The backlight unit 200 according to the second embodiment (hereinafter simply referred to as “backlight unit 200”) is substantially the same as the backlight unit 100 according to the first embodiment of the present invention except for the lamp 201 and the connection member 202. In general. Therefore, the lamp 201 and the electrical connection member 202 will be described in detail, and the other points will be omitted. Note that the length of the lamp 201 in the longitudinal direction is longer than that of the lamp 2 used in the backlight unit 100 according to the first embodiment of the present invention by the length of the external connection terminal 203. Also in this case, the lamp is held by the lamp holding member 101 at positions spaced apart from each other by 0.2113 L ₂ [mm] at the center in the longitudinal direction.

<Explanation of lamp>
As shown in FIG. 10, the lamp 201 is a cold cathode fluorescent lamp in which external connection terminals 203 are provided on the outer periphery of both ends of the glass bulb 7 of the lamp 2 used in the backlight unit according to the first embodiment of the present invention. Therefore, the external connection terminal 203 will be described in detail, and the other points will be omitted.

  The external connection terminal 203 is provided so as to cover the outer peripheral surfaces of both ends of the glass bulb 7. The external connection terminal 203 is made of, for example, solder and joined to the external lead wire 8b.

  In general, solder is suitable as a material for the external connection terminal 203 because of good conductivity, low thermal conductivity, and low price. In particular, a solder mainly composed of tin (Sn), tin-indium (In) alloy, tin-bismuth (Bi) alloy or the like can form the external connection terminal 203 having high mechanical strength, and thus is more preferable. It is. Among them, antimony (Sb), zinc (Zn), aluminum (Al), gold (Au), silver (Ag), copper (Cu), iron (Fe), platinum (Pt) and palladium (Pd) The solder to which at least one kind is added has good compatibility with glass, and thus can form the external connection terminal 203 that is difficult to peel off from the glass bulb 7, and is more preferable. In addition, solder containing no lead is preferable because the lamp 201 can be manufactured in consideration of the environment. The material for forming the external connection terminal 203 is not limited to solder, and may be any material having at least conductivity.

  In FIG. 10, the surface of the external lead wire 8 b is covered with the external connection terminal 203, but the external lead wire 8 b may protrude from the external connection terminal 203. Further, the external connection terminals 203 are not necessarily provided at both ends of the glass bulb 7, and may be provided only on one side.

  Further, as shown in FIG. 12, the external connection terminal 205 may be composed of a sleeve 205a made of Fe / Ni alloy and solder 205b. The sleeve 205a is, for example, a cylinder whose cross section cut perpendicularly to the tube axis is formed in a substantially C shape and has a thickness of 120 [μm] and a longitudinal length Q of 10 [mm], It is fitted on the end of the glass bulb 7. The inner diameter of the sleeve 205a is slightly smaller than the outer diameter of the glass bulb 7, and a slit (not shown) is provided. Therefore, the inner surface of the sleeve 205 a is designed to be in close contact with the outer surface of the glass bulb 7 even if a slight dimensional error occurs between the inner diameter of the sleeve 205 a and the outer diameter of the glass bulb 7.

  The sleeve 205a is not limited to a cylinder having a substantially C-shaped cross section cut perpendicular to the tube axis, but is a polygonal cylinder such as a substantially triangular shape or a substantially rectangular shape, or an elliptical cylinder. The body may be provided with slits. Moreover, the case where a slit is not provided is also considered.

  The lamps 201 and 204 may be those in which the external connection terminals 203 and 205 are provided on the flat lamps 106 and 108 used in the backlight unit 100 according to the first embodiment.

<Description of connecting member>
The connection member 202 includes a connection portion 202a and a power supply lead wire 102a. The connecting portion 202a is conductive and is formed by bending a plate material such as stainless steel or phosphor bronze, and has an opening into which the lamps 201 and 204 can be inserted. The shape is substantially C-shaped. In addition, it is preferable that the substantially C-shaped inner diameter of the connecting portion 202a when the lamps 201 and 204 are not fitted is slightly smaller than the outer diameter of the end portions of the lamps 201 and 204. This is to ensure the stability of the connection when the lamps 201 and 204 are fitted in the connection portion 202a.

  By inserting and fitting the external connection terminals 203 and 205 of the lamps 201 and 204 through the opening of the connection part 202a, the connection part 202a and the external connection terminals 203 and 205 of the lamps 201 and 204 are caused by the leaf spring action of the connection part 202a. 205 is in contact with and electrically connected. Since the connection portion 202a is connected to the power supply lead wire 102a, the lamps 201 and 204 are electrically connected to the connection portion 202a, and thus connected to a lighting circuit (not shown) via the power supply lead wire 102a. Connected.

The connecting member 202 may have substantially the same configuration as the connecting member 112 shown in FIG. However, since the lamps 201 and 204 are connected to the connection member 202 via the external connection terminals 203 and 205 to obtain electric power, the first embodiment of the present invention is connected to the lead wire 8 of the lamp 2. The dimensions are different from those of the connection member 112 used in the backlight unit 100 according to the above. Specifically, it is preferable that M ₁ shown in FIG. 8 is 8 [mm], N ₁ is 3.8 [mm], and P ₁ is 5 [mm]. It is preferable that the size of the connection member 202 is appropriately adjusted according to the tube diameter of the lamps 201 and 204.

<Summary>
The backlight unit 200 according to the second embodiment of the present invention can eliminate the deflection of the lamps 201 and 204 in the backlight unit 200 with the above-described configuration, thereby eliminating the luminance unevenness as the backlight unit 200. The lamps 201 and 204 can be prevented from being damaged. In order to eliminate the uneven brightness, it is preferable that the deflection of the lamps 201 and 204 is suppressed to 5 [mm] or less.

  Further, when the lamps 201 and 204 are connected to the lighting circuit by the connection member 112, the lamps 201 and 204 are disposed when the backlight unit 200 is arranged so that the x direction on the paper surface of FIG. Therefore, the luminance unevenness as the backlight unit 200 can be eliminated, and the lamps 201 and 204 can be prevented from being damaged.

(Third embodiment)
FIG. 13 shows an exploded perspective view of a backlight unit according to the third embodiment of the present invention. FIG. 14 is a sectional view taken along line GG ′, and FIG. 15 is a plan view thereof (excluding the optical sheets 4 and the cover 113). The backlight unit 300 according to the third embodiment (hereinafter simply referred to as “backlight unit 300”) is a direct type, and the configuration other than the lamp 301 and the connection member 302 is the first embodiment of the present invention. The backlight unit 100 has substantially the same configuration. Therefore, hereinafter, the lamp 301 and the connection member 302 will be described, and the other points will be omitted. Note that the length of the lamp 301 in the longitudinal direction is shorter than the lamp 2 of the backlight unit 100 according to the first embodiment by the length of the lead wire 8. Also in this case, the lamp is held by the lamp holding member 101 at positions spaced apart from each other by 0.2113 L ₃ [mm] in the center in the longitudinal direction.

<Explanation of lamp>
As shown in FIG. 14, the lamp 301 includes an external tube composed of a straight tubular glass bulb 7 whose both ends are sealed and an external electrode 303 provided directly on the outer peripheral surface of both ends of the glass bulb 7. This is an electrode type fluorescent lamp.

  The phosphor layer 110 is formed on the inner peripheral surface of the glass bulb 7, but the phosphor layer 110 may not be formed on the inner peripheral surface of the glass bulb 7 and corresponding to the external electrode 303. preferable. This portion is exposed to discharge while the lamp 301 is lit, and thus the phosphor is likely to deteriorate when the phosphor layer is formed. Note that a protective layer 304 may be formed in this portion. The protective layer 304 is made of a metal oxide (for example, yttrium oxide) excluding a metal oxide precipitated from the glass bulb 7 (sodium oxide or the like when the material of the glass bulb 7 is soda glass).

  In addition, the dark start-up characteristics of the lamp 301 can be improved by including an electron radioactive substance such as cesium (Cs) in the protective layer 304.

  Further, the glass bulb 7 is filled with a mixed gas of argon and neon that has a pressure of about 8 [kPa] when lit at room temperature, and about 2 [mg] of mercury.

  The external electrode 303 is made of, for example, an aluminum metal foil, and is attached so as to cover the outer peripheral surfaces of both ends of the glass bulb 7 with a conductive adhesive (not shown) in which metal powder is mixed with silicon resin. Yes.

  Note that a fluororesin, a polyimide resin, an epoxy resin, or the like may be used as the conductive adhesive instead of the silicon resin. Further, instead of sticking the metal foil to the glass bulb 7 with the conductive adhesive, the external electrode 303 may be formed by applying a silver paste to the entire circumference of the electrode forming portion of the glass bulb 7. In this case, it is possible to prevent the external electrode 303 from being peeled off due to deterioration of the conductive adhesive material. When a solder film is formed on the external electrode 303, the external electrode 303 can be protected from damage. It is also possible to form the external electrode 303 with only a solder film by a known method such as ultrasonic solder dipping. The external electrode 303 of the lamp 301 shown in FIGS. 13 to 15 is not formed up to the tube end of the glass bulb 7 but is formed in a headband shape so as to cover the entire tube end of the glass bulb 7. An external electrode 303 may be formed.

  Alternatively, the external electrode 303 may be formed by covering a metal sleeve such as an Fe / Ni alloy and performing a solder dipping process thereon.

<Description of connecting member>
The connecting member 302 has a configuration in which each power supply lead wire 102a of the connecting member 202 used in the backlight unit according to the third embodiment of the present invention is connected to the connecting portion 302a. With this configuration, the lamps 301 are not connected to individual lighting circuits (not shown), but are connected to the same lighting circuit via the connecting portion 302a.

<Description of another connecting member>
Note that the configuration of the connection member 302 is not limited to the above configuration. For example, a connecting member 305 as shown in FIG. 16 may be used. The connection member 305 includes a U-shaped portion 305a and a leg portion 305b. As shown in FIG. 16, the U-shaped portion 305a has a U-shaped shape having an opening in the upward direction, so that the external electrode 303 of the lamp 301 can be inserted into a groove 305c formed by the U-shape. It has become. Further, the upper end of the U-shaped portion 305a is bent outward so that the external electrode 303 of the lamp 301 can be easily inserted. Height M ₂ of the groove portion 305c is 8 [mm], a width N ₂ is 3.8 [mm], it is preferable the depth P ₂ is 20 [mm].

  The leg portion 305 b connects the U-shaped portion 305 a and fixes the connection member 305 to the housing 3. Further, the connection member 302 is configured such that each U-shaped portion 305a is connected to a common lighting circuit (not shown) via a lighting circuit power supply lead (not shown) from an arbitrary part of the leg portion 305b. Yes.

<Summary>
Since the backlight unit 300 according to the third embodiment of the present invention can eliminate the deflection of the lamp 301 in the backlight unit 300 with the above-described configuration, the luminance unevenness as the backlight unit 300 can be eliminated. And the breakage of the lamp 301 can be prevented. In order to eliminate the uneven luminance, it is preferable that the deflection of the lamp 301 is suppressed to 5 [mm] or less.

  Further, when the lamp 301 is connected to the lighting circuit by the connection member 305, the deflection of the lamp 301 is eliminated when the backlight unit 300 is arranged so that the x direction on the paper surface of FIG. Therefore, unevenness in luminance as the backlight unit 300 can be eliminated, and damage to the lamp 301 can be prevented.

(Fourth embodiment)
An exploded perspective view of a backlight unit according to the fourth embodiment of the present invention is shown in FIG. FIG. 18 is a sectional view taken along the line H-H ′, and FIG. 19 is a plan view thereof (excluding the optical sheets 4 and the cover 113). The backlight unit 400 according to the fourth embodiment (hereinafter simply referred to as “backlight unit 400”) has substantially the same configuration as that of the first embodiment of the present invention except for the lamp 401 and the connection member 102. is doing. Therefore, the lamp 401 and the connection member 102 will be described in detail, and the other points will be omitted. Note that the length of the lamp 401 in the longitudinal direction differs from the lamp 2 of the backlight unit 100 according to the first embodiment by the difference between the lead wire 8 and the lead wire 404. Also in this case, the lamp holding members 101 hold the lamps at positions spaced apart from each other by 0.2113 L ₄ [mm] in the center in the longitudinal direction.

<Explanation of lamp>
The lamp 401 is a hot cathode fluorescent lamp, and includes a glass bulb 7 and an electrode 402.

  For example, the glass bulb 7 has a total length of 1010 [mm], an outer diameter of 18 [mm], and a wall thickness of 0.8 [mm], and electrodes 402 are sealed at both ends thereof.

  A phosphor layer 110 is formed on the inner surface of the glass bulb 7, and mercury (for example, 4 [mg] to 10 [mg]) is sealed inside the glass bulb 7, and argon ( A mixed gas of Ar) and krypton (Kr) (for example, a mixed gas having a ratio of Ar of 50 [%] and Kr of 50 [%]) is sealed at a sealed gas pressure of 600 [Pa], for example.

  As shown in FIG. 18, the electrode 402 is a so-called bead glass mount, and a tungsten filament coil 403, a pair of lead wires 404 that support the filament coil 403, and the pair of lead wires 404 are fixedly supported. Bead glass 405.

  Of the electrode 402, a part of the lead wire 404 is sealed to the end of the glass bulb 7, specifically, a part extending from the bead glass 405 to the side opposite to the filament coil 403. The electrode 402 is sealed to the glass bulb 7 by, for example, pinch sealing.

  An exhaust pipe 406 is attached together with the electrode 402 to at least one end of the glass bulb 7. The exhaust pipe 406 is used to exhaust the inside of the glass bulb 7 or seal the buffer gas or the like after the electrode 402 is sealed. The inside of the glass bulb 7 is filled with the buffer gas or the like. When completed, for example, chip-off sealing is performed at a portion of the exhaust pipe 406 located outside the glass bulb 7.

<Description of connecting member>
The connection member 102 has substantially the same configuration as the connection member 102 used in the backlight unit 100 according to the first embodiment of the present invention. However, the connection member 102 is electrically connected to each of the two lead wires 404 led out from the end portions of the lamps 401.

<Description of another connecting member>
Note that the configuration of the connecting member 102 is not limited to the above configuration. For example, a connection member 407 as shown in FIG. 20 may be used. The connecting member 407 includes a continuous U-shaped portion 407a and a leg portion 407b. As shown in FIG. 20, the continuous U-shaped portion 407 a has two U-shaped shapes having openings in the upward direction, and the lamp 401 has a groove 407 c formed by each U-shape. A lead wire 404 can be inserted. Further, the upper end of the continuous U-shaped portion 407a is bent outward so that the lead wire 404 of the lamp 401 can be easily inserted. For example, the height M ₃ of the groove 407c is preferably 8 [mm], the width N ₃ is 3.8 [mm], and the depth P ₃ is preferably 2 [mm].

  The leg portion 407 b is for connecting the continuous U-shaped portion 407 a and inserting a screw into the screw hole 407 d to fix the connection member 407 to the housing 3.

<Summary>
Since the backlight unit 400 according to the fourth embodiment of the present invention can eliminate the deflection of the lamp 401 in the backlight unit 400 with the above-described configuration, the luminance unevenness as the backlight unit 400 can be eliminated. And the breakage of the lamp 401 can be prevented.

  Further, when the lamp 401 is connected to the lighting circuit by the connecting member 407, the deflection of the lamp 401 is eliminated when the backlight unit 400 is arranged so that the x direction on the paper surface of FIG. Therefore, uneven brightness as the backlight unit 400 can be eliminated, and damage to the lamp 401 can be prevented. In order to eliminate the uneven brightness, it is preferable that the deflection of the lamp 401 is suppressed to 5 [mm] or less.

(Fifth embodiment)
FIG. 21 shows a schematic perspective view of a liquid crystal display device 500 according to the fifth embodiment of the present invention. As shown in FIG. 21, a liquid crystal display device 500 is, for example, a 32 [inch] liquid crystal television, a liquid crystal screen unit 501 including a liquid crystal panel and the like, a backlight unit 100 according to the first embodiment of the present invention, and a lighting circuit 502. With.

  The liquid crystal screen unit 501 is a publicly known one and includes a liquid crystal panel (color filter substrate, liquid crystal, TFT substrate, etc.) (not shown), a drive module, etc. (not shown), and is based on an image signal from the outside. To form a color image.

  The lighting circuit 502 lights the lamp 2 inside the backlight unit 100. The lamp 2 is operated at, for example, a lighting frequency of 40 [kHz] to 100 [kHz] and a lamp current of 3.0 [mA] to 25 [mA].

  In the fifth embodiment of the present invention, the case where the backlight unit 100 according to the first embodiment of the present invention, specifically, the cold cathode fluorescent lamp 2 is applied as the light source device has been described. However, the backlight unit 200 according to the second embodiment of the present invention, specifically, the case where the cold cathode fluorescent lamps 201 and 204 having the external connection terminals 203 and 205 are applied, or the third embodiment of the present invention. When the backlight unit 300 according to the embodiment, specifically, the external electrode type fluorescent lamp 301 is applied, or the backlight unit 400 according to the fourth embodiment of the present invention, specifically, the hot cathode fluorescent lamp 401 is applied. It can also be applied to cases.

  Since the liquid crystal display device 500 according to the fifth embodiment of the present invention uses the backlight units 100, 200, 300, and 400 according to the first to fourth embodiments, the backlight units 100, 200, and 300 are used. , 400, the deflection of the lamps 2, 201, 204, 301, 401 is eliminated, and the luminance unevenness of the backlight units 100, 200, 300, 400 as a whole can be eliminated, so that the image quality is further improved. A liquid crystal display device 500 can be provided. In order to eliminate the uneven brightness, it is preferable that the deflection of the lamp is suppressed to 5 [mm] or less.

<Modification>
As described above, the present invention has been described based on the specific examples shown in the above embodiments. However, the content of the present invention is not limited to the specific examples shown in the respective embodiments. Variations can be used.

1. Structure of glass Moreover, the sealing strength with the lead wire 8 of the lamp | ramp 2 can be raised by adjusting the thermal expansion coefficient of glass. For example, in the case where the lead wire 8 is made of tungsten (W), it is preferably set to 36 × 10 ⁻⁷ [K ⁻¹ ] to 45 × 10 ⁻⁷ [K ⁻¹ ]. In this case, the thermal expansion coefficient of glass can be made into said range by making the sum total of the alkali metal component and alkaline-earth metal component in glass into 4 [mol%]-10 [mol%].

In addition, when the lead wire 8 is made of Kovar or molybdenum (Mo), it is preferable to set it to 45 × 10 ⁻⁷ [K ⁻¹ ] to 56 × 10 ⁻⁷ [K ⁻¹ ]. In this case, the thermal expansion coefficient of glass can be made into said range by making the sum total of the alkali metal component and alkaline-earth metal component in glass into 7 [mol%]-14 [mol%].

Further, when the lead wire 8 is made of Dumet, it is preferably in the vicinity of 94 × 10 ⁻⁷ [K ⁻¹ ]. In this case, the thermal expansion coefficient of glass can be made into said range by making the sum total of the alkali-metal component and alkaline-earth metal component in glass into 20 [mol%]-30 [mol%].

Further, it is possible to absorb ultraviolet rays of 254 [nm] or 313 [nm] by doping a glass with a predetermined amount of a transition metal oxide depending on its kind. Specifically, for example, in the case of titanium oxide (TiO ₂ ), the composition ratio of 0.05 [mol%] or more is doped to absorb ultraviolet rays of 254 [nm], and the composition ratio is 2 [mol%] or more. Thus, it is possible to absorb ultraviolet rays of 313 [nm]. However, when titanium oxide is doped more than the composition ratio of 5.0 [mol%], the glass is devitrified, so the composition ratio is 0.05 [mol%] or more and 5.0 [mol%] or less. It is preferable to dope in the range.

In the case of cerium oxide (CeO ₂ ), 254 [nm] ultraviolet rays can be absorbed by doping at a composition ratio of 0.05 [mol%] or more. However, when cerium oxide is doped more than 0.5 [mol%], the glass is colored, so cerium oxide has a composition ratio of 0.05 [mol%] to 0.5 [mol%]. It is preferable to dope in the following range. In addition, since coloring of glass by cerium oxide can be suppressed by doping tin oxide (SnO) in addition to cerium oxide, cerium oxide can be doped to a composition ratio of 5.0 [mol%] or less. . In this case, if cerium oxide is doped with a composition ratio of 0.5 [mol%] or more, ultraviolet rays of 313 [nm] can be absorbed. However, even in this case, when the composition ratio of cerium oxide is more than 5.0 [mol%], the glass is devitrified.

In the case of zinc oxide (ZnO), ultraviolet rays of 254 [nm] can be absorbed by doping at a composition ratio of 2.0 [mol%] or more. However, when zinc oxide is doped more than the composition ratio of 10 [mol%], the thermal expansion coefficient of the glass becomes large, and when the lead wire 8 is made of tungsten (W), the thermal expansion coefficient of the sealing member (about 44 × 10 ⁻⁷ [K ⁻¹ ]) and the glass have a coefficient of thermal expansion that makes sealing difficult, so that zinc oxide is contained in the range of 2.0 [mol%] to 10 [mol%]. It is preferable to dope. However, when the lead wire 8 is made of Koval or molybdenum (Mo), the thermal expansion coefficient of the sealing member (about 51 × 10 ⁻⁷ [K ⁻¹ ]) is larger than that made of tungsten. Therefore, zinc oxide can be doped to a composition ratio of 14 [mol%] or less.

Further, in the case of iron oxide (Fe ₂ O ₃ ), 254 [nm] ultraviolet rays can be absorbed by doping at a composition ratio of 0.01 [mol%] or more. However, when iron oxide is doped more than the composition ratio of 2.0 [mol%], the glass is colored, so the iron oxide is contained in the composition ratio of 0.01 [mol%] to 2.0 [mol%]. It is preferable to dope in the following range.

  The infrared transmittance coefficient indicating the water content in the glass is preferably adjusted to be in the range of 0.3 to 1.2, particularly 0.4 to 0.8. If the infrared transmittance coefficient is 1.2 or less, it is easy to obtain a low dielectric loss tangent applicable to a high voltage application lamp such as an external electrode type fluorescent lamp (EEFL) or a long cold cathode fluorescent lamp. If it is below, the dielectric loss tangent becomes sufficiently small and can be applied to a high voltage application lamp.

  The infrared transmittance coefficient (X) can be expressed by the following formula.

[Expression 1] X = (log (a / b)) / t
a: Transmittance [%] of a minimum point in the vicinity of 3840 [cm ⁻¹ ]
b: Transmittance [%] of a minimum point in the vicinity of 3560 [cm ⁻¹ ].
t: Glass thickness Configuration of Phosphor (1) About UV Absorption For example, in recent years, with the increase in size of liquid crystal color televisions, polycarbonate having good dimensional stability is used for the diffusion plate that closes the opening of the backlight unit. This polycarbonate is easily deteriorated by ultraviolet rays having a wavelength of 313 (nm) emitted from mercury. In such a case, a phosphor that absorbs ultraviolet rays having a wavelength of 313 (nm) may be used. Examples of phosphors that absorb ultraviolet rays of 313 (nm) include the following.

(A) Blue Europium / manganese co-activated barium aluminate / strontium / magnesium [Ba _1-xy Sr _x Eu _y Mg _1-z Mn _z Al ₁₀ O ₁₇ ] or [Ba _1-xy Sr _x Eu _y Mg _{2− z} Mn _z Al ₁₆ O ₂₇ ]
Here, x, y, and z are preferably numbers satisfying the conditions of 0 ≦ x ≦ 0.4, 0.07 ≦ y ≦ 0.25, and 0 ≦ z <0.1, respectively.

Examples of such phosphors include europium activated barium magnesium aluminate [BaMg ₂ Al ₁₆ O ₂₇ : Eu ²⁺ ], [BaMgAl ₁₀ O ₁₇ : Eu ²⁺ ] (abbreviation: BAM-B), Europium activated barium aluminate / strontium / magnesium [(Ba, Sr) Mg ₂ Al ₁₆ O ₂₇ : Eu ²⁺ ], [(Ba, Sr) MgAl ₁₀ O ₁₇ : Eu ²⁺ ] (abbreviation: SBAM-B) Etc.

(B) Green • Manganese inactive magnesium gallate [MgGa ₂ O ₄ : Mn ²⁺ ] (abbreviation: MGM)
Manganese activated cerium aluminate, magnesium, zinc [Ce (Mg, Zn) Al ₁₁ O ₁₉ : Mn ²⁺ ] (abbreviation: CMZ)
· Active aluminate, cerium-magnesium with terbium ^{_{[CeMgAl 11 O 19: Tb 3+}} ] ( abbreviation: CAT)
• Europium • Manganese co-activated barium aluminate • Strontium • Magnesium [Ba _{1 -xy} Sr _x Eu _y Mg _{1 -z} Mn _z Al ₁₀ O ₁₇ ] or [Ba _{1 -xy} Sr _x Eu _y Mg _{2 -z} Mn _z Al ₁₆ O ₂₇ ]
Here, x, y and z are numbers satisfying the conditions of 0 ≦ x ≦ 0.4, 0.07 ≦ y ≦ 0.25, and 0.1 ≦ z ≦ 0.6, respectively, and z is 0.4 It is preferable that ≦ x ≦ 0.5.

Examples of such phosphors include europium / manganese co-activated barium aluminate / magnesium [BaMg ₂ Al ₁₆ O ₂₇ : Eu ²⁺ , Mn ²⁺ ], [BaMgAl ₁₀ O ₁₇ : Eu ²⁺ , Mn ^{2]. +} ] (Abbreviation: BAM-G), europium / manganese co-activated barium aluminate / strontium / magnesium [(Ba, Sr) Mg ₂ Al ₁₆ O ₂₇ : Eu ²⁺ , Mn ²⁺ ], [(Ba, Sr) MgAl ₁₀ O ₁₇ : Eu ²⁺ , Mn ²⁺ ] (abbreviation: SBAM-G).

(C) Red • Europium activated phosphorus • Yttrium vanadate [Y (P, V) O ₄ : Eu ³⁺ ] (abbreviation: YPV)
Europium activated yttrium vanadate [YVO ₄ : Eu ³⁺ ] (abbreviation: YVO)
・ Europium-activated yttrium oxysulfide [Y ₂ O ₂ S: Eu ³⁺ ] (abbreviation: YOS)
Manganese-activated magnesium fluoride germanate [3.5MgO.0.5MgF ₂ .GeO ₂ : Mn ⁴⁺ ] (abbreviation: MFG)
Dysprosium-activated yttrium vanadate [YVO ₄ : Dy ³⁺ ] (red and green two-component phosphor, abbreviation: YDS)
In addition, you may mix and use the fluorescent substance of a different compound with respect to one type of luminescent color. For example, only BAM-B (absorbs 313 nm) in blue, LAP (absorbs 313 nm) and BAM-G (absorbs 313 nm) in green, YOX (does not absorb 313 nm) and YVO in red. A phosphor (absorbing 313 nm) may be used. In such a case, as described above, the phosphor that absorbs the wavelength 313 (nm) is adjusted so that the total weight composition ratio is larger than 50%, so that the ultraviolet ray almost leaks out of the glass tube. Can be prevented. Therefore, when the phosphor layer 105 includes a phosphor that absorbs ultraviolet rays of 313 [nm], deterioration due to ultraviolet rays such as a diffusion plate made of polycarbonate (PC) that closes the opening of the backlight unit is suppressed, The characteristics as a backlight unit can be maintained for a long time.

  Here, “absorbing ultraviolet rays of 313 (nm)” means an excitation wavelength spectrum near 254 (nm) (excitation wavelength spectrum means that excitation light is emitted while changing the wavelength of the phosphor, and the excitation wavelength and emission intensity are changed. It is defined that the intensity of the excitation wavelength spectrum of 313 (nm) is 80 (%) or more, where the intensity is plotted (100). That is, the phosphor that absorbs ultraviolet rays of 313 (nm) is a phosphor that can absorb ultraviolet rays of 313 (nm) and convert it into visible light.

(2) High color reproduction Liquid crystal display devices typified by liquid crystal color televisions have been used as a light source for a backlight unit of the liquid crystal display device in accordance with the recent high color reproduction that has been made as part of higher image quality. There is a need to expand the reproducible chromaticity range in cathode fluorescent lamps and external electrode fluorescent lamps.

  In response to such a request, for example, by using the following phosphor, the chromaticity range can be expanded as compared with the case of using the phosphor in the embodiment. Specifically, in the CIE1931 chromaticity diagram, the chromaticity coordinate value of the phosphor for high color reproduction includes a triangle formed by connecting the chromaticity coordinate values of the three phosphors used in the embodiment. Located at the coordinates that expand the reproduction range.

(A) Blue • Europium-activated strontium chloroapatite [Sr ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu ²⁺ ] (abbreviation: SCA), chromaticity coordinates: x = 0.151, y = 0.065
In addition to the above, europium activated strontium, calcium, barium, chloroapatite [(Sr, Ca, Ba) ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu ²⁺ ] (abbreviation: SBCA) can also be used, and the wavelength 313 (nm) SBAM-B, which can absorb ultraviolet rays), can also be used for high color reproduction.

(B) Green BAM-G, chromaticity coordinates: x = 0.139, y = 0.574
CMZ, chromaticity coordinates: x = 0.164, y = 0.722
CAT, chromaticity coordinates: x = 0.267, y = 0.663
As described above, these can also absorb ultraviolet rays having a wavelength of 313 (nm), and besides the three phosphor particles described here, MGM can also be used for high color reproduction.

(C) Red • YOS, chromaticity coordinates: x = 0.651, y = 0.344
YPV, chromaticity coordinates: x = 0.658, y = 0.333
MFG, chromaticity coordinates: x = 0.711, y = 0.287
As described above, these can also absorb ultraviolet rays having a wavelength of 313 (nm). Besides the three phosphor particles described here, YVO and YDS can also be used for high color reproduction.

  In addition, the chromaticity coordinate values shown above are representative values measured only with each phosphor powder, and due to the measurement method (measurement principle), etc., the chromaticity coordinates indicated by each phosphor powder The value may be slightly different from the value listed above. For reference, the chromaticity coordinate values of the phosphor powders of the first embodiment are YOX (x = 0.644, y = 0.353), LAP (x = 0.351, y = 0.585). , BAM-B (x = 0.148, y = 0,056).

  Furthermore, the phosphor used for emitting each color of red, green, and blue is not limited to one type for each wavelength, and a plurality of types may be used in combination.

  Here, the case where a phosphor layer is formed using the above-described phosphor particles for high color reproduction will be described. In this evaluation, there are three evaluations in the case of using a phosphor for high color reproduction based on the area of the NTSC triangle (NTSC triangle) connecting the chromaticity coordinate values of the three primary colors of the NTSC standard in the CIE1931 chromaticity diagram. A triangular area ratio formed by connecting chromaticity coordinate values (hereinafter referred to as NTSC ratio) is used.

  For example, when BAM-B is used as blue, BAM-G as green, and YVO as red (Example 1), the NTSC ratio is 92%, and SCA is used as blue, BAM-G as green, and YVO as red. (Example 2) NTSC ratio is 100%, and when SCA is used as blue, BAM-G as green, and YOX as red (Example 3), NTSC ratio is 95 (%). The luminance can be improved by 10 (%) compared to the above.

  The chromaticity coordinate values used for the evaluation here are measured in a state where a liquid crystal display device incorporating a lamp or the like is used.

3. Composition of rare gas The rare gas contains, for example, at least one kind of helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), etc., and two or three kinds are mixed. It may be used. For example, argon (Ar100 [%]) may be used, or neon-krypton mixed gas (Ne95 [%] + Kr5 [%]) may be used. When a neon / krypton mixed gas is used as the rare gas, the startability of the lamp 2 is improved, and the lamp 2 can be lit at a low voltage.

4). Auxiliary Member As shown in FIG. 22, an auxiliary member 117 may be provided in the vicinity of the middle portion of the lamp in the longitudinal direction inside the housing. When the backlight unit 100 is moved, the lamp 2 is more easily bent in the y direction than in the x direction on the paper surface of FIG. If the middle part of the lamp 2 is bent greatly due to an unexpected impact or the like during movement, the lamp 2 may be damaged. Therefore, by providing the auxiliary member 117 in the vicinity of the intermediate portion where the deflection of the lamp 2 is the largest, it is possible to suppress the deflection of the lamp 2 more than necessary and prevent the lamp 2 from being damaged.

  The auxiliary member 117 is a rod-shaped body made of, for example, silicone resin and perpendicular to the bottom surface of the housing. The material, shape, and the like of the auxiliary member 117 are not limited to the above configuration. The material may be, for example, a polycarbonate resin, a polyacetal resin, a fluororesin, or the like. The shape may be, for example, a rectangular parallelepiped or a cylindrical shape. Further, the number of auxiliary members provided is not limited to one between the lamps 2 as shown in FIG. 22, and a plurality of auxiliary members may be provided.

  The present invention can be widely applied to backlight units and liquid crystal display devices.

1 is an exploded perspective view of a backlight unit according to a first embodiment of the present invention. Similarly AA 'cross section Same top view A perspective view of a lamp holding member also used in the backlight unit The top view of the modification 1 of a backlight unit similarly (A) Cross-sectional view including the tube axis of the modified example 1 of the lamp that is also used in the backlight unit, (b) Cross-sectional view along BB ′, (c) Cross-sectional view along CC ′ (A) Cross-sectional view including the tube axis of the second modified example of the lamp used in the backlight unit, (b) Cross-sectional view along DD ', (c) Cross-sectional view along EE' The perspective view of the modification of the connection member similarly used for a backlight unit The disassembled perspective view of the backlight unit which concerns on the 2nd Embodiment of this invention. Cross-sectional view of line FF ' Same top view Sectional drawing including the tube axis of the modified example of the lamp | ramp similarly used for a backlight unit The disassembled perspective view of the backlight unit which concerns on the 3rd Embodiment of this invention. GG 'sectional view Same top view The perspective view of the modification of the connection member similarly used for a backlight unit The disassembled perspective view of the backlight unit which concerns on the 4th Embodiment of this invention. Similarly HH 'cross section Same top view The perspective view of the modification of the connection member similarly used for a backlight unit The perspective view of the liquid crystal display device which concerns on the 5th Embodiment of this invention. The top view of the modification 2 of the backlight unit which concerns on the 1st Embodiment of this invention. An exploded perspective view of a conventional backlight unit A perspective view of a conventional lamp holding member

Explanation of symbols

3 Housing 2, 201, 204, 301, 401 Lamp 102, 112, 202, 302, 305, 407 Connection member 100, 200, 300, 400 Backlight unit 4 Optical sheet 7 Glass bulb 500 Liquid crystal display

Claims (6)

A housing having an opening for taking out light; a lamp housed in the housing; and a connecting member for connecting the lamp to a lighting circuit; The glass bulb of the lamp is composed of glass having an alkali metal content of 3 [mol%] to 20 [mol%] . The backlight unit according to claim 1, wherein a lamp holding member is provided near an airy point between both ends of the lamp. 3. The back according to claim 2, wherein the airy point is located at a distance of 0.2113 L [mm] from both ends of the lamp having a total length L [mm] toward a central portion in the longitudinal direction of the lamp. Light unit. The backlight unit according to claim 2 or 3, characterized in that optical sheets supporting member for supporting the optical sheets to be positioned on the front of the housing to said lamp holding member. The lamp has a flat shape at least in a cross section cut perpendicular to the tube axis of the light extraction portion, and a major axis of a portion in which the cross section cut perpendicular to the tube axis of the lamp is flat has a long diameter of the casing. The backlight unit according to claim 1, wherein the backlight unit is substantially parallel to optical sheets positioned on the front surface. A liquid crystal display device comprising the backlight unit according to claim 1.

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