JP4158521B2 - Lighting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lighting device using a cathode tube.
[0002]
[Prior art]
Conventionally, as a backlight for a liquid crystal display element, a cathode tube is disposed opposite to one end face of the light guide plate, and light emitted linearly from the cathode tube is guided into the light guide plate and is provided on the back surface of the liquid crystal display element. A sidelight type surface light source device that emits in a planar shape from one surface facing each other is often used.
[0003]
As a method of holding the cathode tube in this surface light source device, the both ends where the electrodes of the cathode tube are provided are usually covered and protected by a rubber holder, and these ends are sandwiched between the case corner and holding claws via the rubber holder. The method to do is adopted. (For example, see Patent Document 1)
[0004]
[Patent Document 1]
JP 11-337939 A (page 4, FIG. 4)
[0005]
[Problems to be solved by the invention]
In the above-described holding method, the wall of the case corner portion is used as one of the clamping means, and therefore, the wall of the case corner portion and the rubber holder are brought into close contact with each other. Therefore, the heat generated at the electrode portions at both ends is conducted from the rubber holder through the wall of the case and dissipated to the outside relatively quickly.
[0006]
As a result, the heat generated at the electrode portions at both ends when the cathode tube is lit cannot be effectively used to heat the cathode tube. In the first place, the cathode tube has the disadvantage that the rise time until normal lighting at low temperature is long, and in order to raise the temperature of the entire cathode tube from the electrode as quickly as possible at the time of lighting, it is generated at the electrode part by applying voltage. It is necessary to prevent external heat dissipation as much as possible and to effectively use the heat to heat the cathode tube.
[0007]
On the other hand, even when the cathode tube is turned off, heat dissipation at both end electrode portions becomes a problem. That is, mercury as a luminescent factor enclosed in the cathode tube has a characteristic that it easily moves from a high temperature to a low temperature. Therefore, if the temperature of the both end electrodes drops faster than the center due to heat dissipation to the outside when the cathode tube is extinguished, mercury gradually gathers around the both ends of the cathode tube as the cathode tube is repeatedly turned on and off. End up. As a result, effective mercury that contributes to the light emission of the cathode tube light emitting portion (center side excluding both end electrode portions) gradually decreases, causing a reduction in luminance or life of the cathode tube.
[0008]
The present invention relates to an illuminating device using a cathode tube as a light source, which has a short rise time until normal lighting at the time of lighting, and suppresses the movement of mercury to the end when the light is turned off, thereby ensuring a desired luminance and lifetime. It is an issue to provide.
[0009]
[Means for Solving the Problems]
The lighting device of the present invention comprises a box comprising a cathode tube, light guiding means for guiding and emitting light emitted from the cathode tube in a predetermined direction, and a bottom plate and a side wall provided upright around the bottom plate. None, a lighting case in which the inside of the box body is divided into a plurality of chambers by partition walls, and the cathode tube and the light guiding means are respectively housed in the corresponding chambers of the housing case The storage case includes a side wall of the storage case, a partition wall, and a space between the partition wall and the side wall for storing the vicinity of the electrode placement portions at both ends of the cathode tube , respectively. Each having a pair of tube end accommodating chambers formed by ribs projecting from each other, and the tube end accommodating chambers are formed by projecting from the side walls of the storage case and the partition walls, respectively. The tube end of the cathode tube A plurality of support protrusions plate for lifting is provided, that they are dimensionally surrounds via a substantially air layer tube end of the cathode tube which is supported the plurality of support protrusions plate by said partition wall It is a feature.
[0010]
According to this illuminating device, a pair of tube end accommodating chambers that respectively accommodate both ends where the electrodes of the cathode tube are formed are provided between the side wall of the storage case, the partition wall, and the partition wall and the side wall. A plurality of support projections formed by ribs protruding from each other and projecting from the side wall of the storage case and the partition wall in the tube end storage chamber and supporting the tube end of the cathode tube Since a plate is provided and each end of the cathode tube is accommodated in a form that is substantially surrounded planarly by an air layer by a wall member such as a case side wall or a partition wall that partitions the tube end accommodating chamber, the tube end conduction to the wall member of the heat generated in the electrode unit is further suppressed to be through air layer. As a result, most of the heat generated in the tube end electrode part is not dissipated to the outside, and at the time of cathode tube lighting, the rise time until normal lighting is shortened by contributing to the temperature rise of the entire cathode tube, A lighting device using a long-life cathode tube that prevents the mercury from moving to the tube end by delaying the temperature drop of the tube end electrode portion from the center side when the cathode tube is turned off, and can ensure the desired luminance over a long period of time. Is obtained.
[0011]
In the illumination device of the present invention, as described in claim 2, it is preferable to attach a rubber holder to each end portion of the cathode tube accommodated in the tube end accommodating chamber, Damage to the tube end electrode portion of the cathode tube is prevented, and conduction of heat generated in the electrode portion to the outside is further suppressed.
[0012]
According to a third aspect of the present invention , each of the tube end accommodating chambers includes a plurality of supporting protrusion plates that support the cathode tube by contacting a rubber cover attached to each end of the cathode tube. Preferably, each end of the cathode tube can be securely held at a predetermined position.
[0013]
Furthermore, as described in claim 4, it is preferable to cover the tube end storage chamber with a lid member that substantially shields the chamber, and thereby, the heat due to conduction of heat generated in the tube end electrode portion. In addition to scattering, the exchange of air with the outside, that is, the dissipation of heat due to convection and radiation is also suppressed, and the heat insulation effect of the tube end accommodating chamber is further enhanced.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
A sidelight type backlight for a liquid crystal display element as an embodiment of the illumination device of the present invention will be described with reference to FIGS. FIG. 1 is a plan view showing a substantially entire configuration of the backlight.
[0015]
In FIG. 1, the storage case 1 has a box shape in which four side walls 1a2 to 1a5 are erected on four sides of a bottom plate 1a1 having a substantially rectangular shape. Inside the storage case 1, a partition wall 1b is provided in a substantially U-shape along side walls 1a2 to 1a4 on three sides. Due to the partition wall 1 b, the inside of the case has a light source storage chamber Rs in which a light source device including the cathode tube 2 is stored, and one lead of a pair of lead wires 3 a and 3 b connected to both end electrode portions of the cathode tube 2. It is partitioned into a wiring storage chamber Rw for storing the wire 3a and a light guide plate storage chamber Rg for storing the light guide plate 4.
[0016]
In the light guide plate storage chamber Rg, the outer shape, the planar shape, and the dimensions of the light guide plate 4 to be stored are formed substantially the same, and the light guide plate 4 can be easily inserted simply by press-fitting the light guide plate 4 from the vertical direction of the case. Yes.
[0017]
The wiring storage chamber Rw is formed in a corridor shape having a substantially U-shape sandwiched between three side walls 1a2 to 1a4 and partition walls 1b erected along these sides on both sides. On the partition wall 1b, nine ribs 1c1 to 1c9 are provided so as to project toward the opposite side walls 1a2 to 1a4. That is, ribs 1c1, 1c9 are provided at both ends of the wiring storage chamber Rw (boundary with the light source storage chamber Rs), long ribs 1c4, 1c7 are provided at two corners, and two ribs are provided near both corners. A total of nine ribs 1c1 to 1c9 are provided: ribs 1c3, 1c5 and ribs 1c6, 1c8, and rib 1c2 facing the middle portion of side wall 1a2. Of these nine ribs 1c1 to 1c9, seven ribs 1c2 and 1c4 to 1c9 are provided with a gap sufficient to hold the lead wire 3a between each tip and the opposite portion of the side walls 1a2 to 1a4. Projected.
[0018]
On the other hand, the side wall 1a2 of the side walls 1a2 to 1a4 is formed in a polygonal line shape corresponding to the outline of the liquid crystal display element in which the present backlight is incorporated, and two convex portions r1 and r2 are formed. Ribs 1d1 and 1d2 are respectively provided on the convex portions r1 and r2 so as to project from the side wall 1a2 toward the partition wall 1b. These ribs 1d1 and 1d2 are spaced apart from the ribs 1c1 and 1c3 facing the respective ribs 1c1 and 1c3 on the partition wall side inside the side wall 1a2 so that the lead wire 3a can be held between the ribs 1c1 and 1c3. Is provided so as to be secured.
[0019]
In the gallery-like wiring storage chamber Rw formed as described above, the lead wire 3a electrically connected to the electrode terminal 2a drawn from the electrode at one end of the cathode tube 2 as shown in FIG. It is arranged around. In the lead wire 3a, the corresponding press-fitting portions of the wiring 3a are surely inserted by pressing the corresponding portions into the gaps between the tips of the ribs 1c1 to 1c9 and the inner surfaces of the side walls 1a2 to 1a4 and the tips of the ribs 1d1 and 1d2. It is clamped and fixed to a pattern that is routed along the inner surface of the side walls 1a2 to 1a4.
[0020]
In the light source storage chamber Rs, a pair of tube end storage chambers Rs1 and Rs2 that respectively store both ends where electrodes (not shown) of the cathode tube 2 are formed, and a tube center side main body portion of the cathode tube 2 are arranged. It consists of a main body storage area Rs3. A reflector 5 is mounted on the main body portion of the cathode tube 2. The reflector 5 is provided so as to surround the cathode tube main body portion with an appropriate space therebetween, and both end portions thereof are fixed to both planes of the end portion of the light guide plate 4 facing the cathode tube. That is, the reflector 5 is installed in a form that surrounds the main body portion of the cathode tube 2 and that the end portion of the light guide plate 4 facing the cathode tube 2 is sandwiched between the both end portions. Accordingly, most of the light emitted from the main body portion of the cathode tube 2 directly enters the end surface 4a of the opposing light guide plate 4 or is reflected by the reflector 5 and enters the light. It is used effectively.
[0021]
FIG. 2 is a partially enlarged plan view showing in detail the pair of tube end accommodating chambers Rs1, Rs2 in the cathode tube accommodating chamber Rs. As shown in FIG. 2, the pipe end storage chamber Rs1 into which the lead wire 3a is drawn is partitioned from the lead wire storage chamber Rw by the rib 1d1 and the rib 1c1 for sandwiching the lead wire 3a. ing. In this pipe end storage chamber Rs1, a side wall 1a2 and a side wall 1a5, which are adjacent to each other to form a corner, are protruded from the side walls 1a and 1f, and a side wall 1a2 and a partition wall 1b facing the side wall 1a2. There are provided clamping projection plates 1g and 1h that are arranged so as to face each other. Among these four protruding plates, the supporting protruding plate 1e has a supporting contact surface 1e1 whose planar shape is T-shaped and spreads on the plane, but the other three protruding plates 1f, 1g, 1h protrude. It is formed in the flat plate which makes an end surface a support surface. These protruding plates may be separated from the side walls 1a2, 1a5 and the partition wall 1b and may be erected on the bottom plate 1a1 of the storage case 1.
[0022]
In the tube end accommodating chamber Rs1 configured as described above, one end of the cathode tube 2 includes side walls 1a2, 1a5, partition walls 1b, and ribs 1d1 and ribs 1c1 that also serve as partition walls (hereinafter referred to as tube end storage). (Referred to as a wall member of the chamber Rs1). The chamber is substantially enclosed in a plane via the air layer As. In this example, a rubber holder 6 is attached to the end of the cathode tube 2 to protect the tube end. The rubber holder 6 of this example is formed in a rectangular parallelepiped, and leads not only to the end portion of the cathode tube 2 but also to the electrode terminal 2b drawn from the cathode tube 2 and the lead wire 3b electrically connected to the electrode terminal 2b in a right angle direction by, for example, solder connection. The terminal 3b1 is also covered collectively. The rubber holder 6 is supported at three locations around it by the supporting projection plates 1e and 1f and the partition wall 1b. In this case, the T-shaped support projection plate 1e has a wide support contact surface 1e1 in contact with the rubber holder 6 and supports the tube end of the cathode tube 2 along its longitudinal direction. In addition, rubber boots 7 and 8 formed in a ring shape are externally attached to the end of the cathode tube 2 covered by the rubber holder 6 and the base of the lead terminal 3b1, respectively, in order to protect the base. It is inserted.
[0023]
The lead wire 3b whose tip is the connection terminal 3b1 is drawn out from the rubber boot 8, drawn in the tube end accommodation chamber Rs1, and drawn out of the storage case 1 through the side wall 1a2. Further, the other lead wire 3a drawn into the tube end accommodation chamber Rs1 is also drawn out of the storage case 1 through the side wall 1a2. Both of these lead wires 3a and 3b are press-fitted and sandwiched in the gap between the sandwiching projection plates 1g and 1h.
As shown in FIG. 3 and FIG. 5 which is a BB sectional view thereof, one tube end of the cathode tube 2 to which the rubber holder 6 is attached, rubber boots 7 and 8, and lead wires 3a and 3b are provided. A cover 9 serving as a lid member is mounted on the tube end accommodation chamber Rs1 accommodated as described above. The cover 9 of this example is made of a resin sheet material such as a PET (polyethylene terephthalate) sheet, has a planar shape that can completely cover the tube end accommodating chamber Rs1, and is in contact with the side wall 1a5 and the ribs 1d1, 1c1. On the sides, folded portions 9a and 9b are formed that are folded toward the bottom surface of the case. By inserting the folded portions 9a and 9b along the respective inner surfaces of the side wall 1a5 and the ribs 1d1 and 1c1 inside the tube end accommodating chamber Rs1, the cover 9 is held at an intended mounting position. Here, a portion where the cover folding portion 9a of the side wall 1a5 is inserted is slightly projected to form a convex portion r3. By inserting the folding portion 9a inside the convex portion r3, the plane of the cover 9 is formed. Movement in the direction is reliably prevented.
[0024]
As described above, one end portion of the cathode tube 2 covered with the rubber holder 6 is substantially air by the wall member including the side walls 1a2, 1a5 of the storage case 1 and the ribs 1d1, 1c1 which also serve as the partition walls. It is accommodated in the tube end accommodating chamber Rs1 in a form surrounded planarly through layers, and the rubber holder 6 and the wall member of the tube end accommodating chamber Rs1 are not in contact with each other, so that the end of the cathode tube 2 is The heat generated in the electrode is suppressed from heat conduction to the outside of the pipe end by the rubber holder 6 covering the end portion, and the wall member of the heat conducted to the rubber holder 6 by the air layer As formed outside the rubber holder 6. Is significantly suppressed. Further, since the tube end accommodating chamber Rs1 is covered with the cover 9, it is difficult for the air in the tube end accommodating chamber Rs1 to be exchanged with the outside air, and the convection of heat generated in the tube end electrode portion is reduced. Dissipation to the outside due to radiation is prevented. Therefore, most of the heat generated in the tube end electrode portion is conducted to the center side of the cathode tube 2 without being dissipated outside the case, and contributes to the temperature increase of the cathode tube 2 as a whole.
[0025]
The rubber holder 6 is supported at three locations around it by the supporting projection plates 1e and 1f and the partition wall 1b. However, the amount of heat conducted from these through the wall member to the outside of the tube end accommodating chamber Rs1 is small. The state in which the end portion of the cathode tube 2 is accommodated in a tube end accommodating chamber in which the supporting projection plates 1e and 1f and the partition wall 1b do not exist without being supported in a plane simply by attaching the rubber holder 6; This is substantially the same as the state of being surrounded by the wall member of the end accommodating chamber in plan view through the air layer.
[0026]
The other end of the cathode tube 2 is also surrounded by a wall member substantially in a plane via an air layer in a tube end storage chamber Rs2 constructed in the same manner as the tube end storage chamber Rs1. Contained. That is, a rubber holder 10 is attached to the other end portion of the cathode tube 2, and the rubber holder 10 is supported by a support projection plate 1i having a T-shaped planar shape, a flat support projection plate 1j, and a partition wall 1b. The other end of the cathode tube 2 is held. Rubber boots 11 and 12 formed in a ring shape are extrapolated at the other end of the cathode tube 2 to which the rubber holder 10 is attached and the bases of the lead terminals 3a1, respectively, in order to protect the bases. ing.
[0027]
As shown in FIG. 3, the other end of the cathode tube 2 to which the rubber holder 10 is attached and the tube end accommodating chamber Rs2 in which the rubber boots 11 and 12 and the lead wires 3a are accommodated as described above, A cover 13 is covered.
[0028]
As described above, the end portion of the cathode tube 2 covered with the rubber holder 10 is substantially interposed through the air layer by the side wall 1a4, 1a5 of the storage case 1 and the wall member including the partition wall 1b and the rib 1c9 which also serves as the partition wall. Generated at the electrode at the other end of the cathode tube 2 by accommodating in the tube end accommodating chamber Rs2 in a planarly enclosed form and not contacting the rubber holder 10 and the wall member of the tube end accommodating chamber Rs2. The heat conducted to the outside of the pipe end is suppressed by the rubber holder 10 covering the end, and the heat conducted to the rubber holder 10 by the air layer As formed outside the rubber holder 10 is conducted to the wall member. Is cut off. Further, since the tube end accommodating chamber Rs2 is covered with the cover 13, it is possible to prevent the heat generated in the tube end electrode portion from diffusing to the outside due to radiation. As a result, the heat generated in the tube end electrode portion is significantly suppressed from escaping to the outside of the case.
[0029]
In this manner, in the illumination device of the present embodiment, heat dissipation generated at the electrode portions at both ends of the cathode tube 2 to the outside is remarkably suppressed at both ends. Therefore, when the cathode tube 2 is turned on, the heat generated at the electrode portions at both ends is efficiently conducted to the center side of the cathode tube 2 without being dissipated, and the entire cathode tube 2 can be quickly turned on at a temperature at which the cathode tube 2 can be normally lit. The temperature can be raised. Further, when the cathode tube 2 is turned off, heat dissipation from the electrode portions at both ends is suppressed, so that the temperature drop is slower than the center side of the tube, and the mercury enclosed inside moves to the tube end portion. The trouble to do is solved. As a result, it is possible to sufficiently ensure the expected luminance and life in the lighting device using the cathode tube.
[0030]
In addition, this invention is not limited to said embodiment.
For example, the rubber holders attached to both ends of the cathode tube in the above embodiment are not essential constituent elements and can be omitted.
[0031]
In addition, support projection plates for supporting both ends of the cathode tube can be omitted. In that case, a hole for inserting the cathode tube and the lead wire is provided in the partition wall of the tube end storage chamber, and the tube end is supported by the partition wall. What is necessary is just composition.
[0032]
Further, the lid member that covers the tube end storage chamber can be omitted, and in that case, the tube end storage chamber becomes a substantially shielded space in a product such as a liquid crystal display module in which the illumination device is incorporated. The product design may be performed as described above, and thereby, a heat insulating effect equivalent to the case where the lid member is provided can be obtained.
[0033]
【The invention's effect】
According to the illuminating device of the present invention, the electrode of the cathode tube is formed by the side wall of the storage case, the partition wall, and the ribs protruding from each other between the partition wall and the side wall . A pair of tube end accommodating chambers for accommodating both ends are formed , and a plurality of tube end supporting chambers are formed in the tube end accommodating chambers so as to protrude from the side wall of the storage case and the partition wall. A supporting projection plate is provided, and each end portion of the cathode tube is substantially surrounded by a wall member such as a case side wall or a partition wall that partitions the tube end accommodating chamber in a plan view through the air layer. because were housed in form, transfer to the wall member of the heat generated in the electrode portion of the tube end is suppressed to be through air layer. As a result, most of the heat generated in the tube end electrode part is not dissipated to the outside, and at the time of cathode tube lighting, the rise time until normal lighting is shortened by contributing to the temperature rise of the entire cathode tube, A lighting device using a long-life cathode tube that prevents the mercury from moving to the tube end by delaying the temperature drop of the tube end electrode portion from the center side when the cathode tube is turned off, and can ensure the desired luminance over a long period of time. Is obtained.
[0034]
Further, in the illumination device of the present invention, as described in claim 2, by attaching a rubber holder to each end of each cathode tube accommodated in the tube end accommodating chamber, Damage to the tube end electrode portion is prevented, and conduction of heat generated in the electrode portion to the outside is further suppressed.
[0035]
Furthermore, as described in claim 3, each of the tube end accommodating chambers includes a plurality of supporting protrusions that support the cathode tube by contacting a rubber cover attached to each end of the cathode tube. By providing, each edge part of a cathode tube can be reliably hold | maintained in a predetermined position.
[0036]
In addition, as described in claim 4, by covering the tube end accommodating chamber with a cover member that substantially shields the chamber, not only the heat conduction generated in the tube end electrode portion but also the dissipation. Further, the heat exchange due to the exchange of air with the outside, that is, convection and radiation is prevented, and the heat insulation effect of the tube end accommodating chamber is further enhanced.
[Brief description of the drawings]
FIG. 1 is a plan view showing an overall schematic configuration of a lighting apparatus according to an embodiment of the present invention.
FIG. 2 is a partially enlarged plan view showing the tube end accommodation chamber in the embodiment with its cover omitted.
FIG. 3 is a partially enlarged plan view showing the tube end accommodation chamber in the embodiment with a cover installed.
4 is a cross-sectional view taken along line AA in FIG.
FIG. 5 is a cross-sectional view taken along the line BB in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Storage case 2 ... Cathode tube 3a, 3b ... Lead wire 4 ... Light guide plate 5 ... Reflector 6, 10 ... Rubber holder 7, 8, 11, 12 ... Rubber boots 9, 13 ... Cover

Claims (4)

A cathode tube;
Light guide means for guiding the light emitted from the cathode tube in a predetermined direction and emitting the light;
A box made of a bottom plate and side walls erected around the bottom plate is formed, and a storage case in which the inside of the box is partitioned into a plurality of chambers by partition walls,
Each of the cathode tube and the light guide means is a lighting device accommodated in each corresponding chamber of the storage case,
The storage case protrudes toward each other between the side wall of the storage case, the partition wall, and the partition wall and the side wall for storing the vicinity of the electrode arrangement portions at both ends of the cathode tube , respectively. Having a pair of tube end accommodation chambers formed by the provided ribs ,
Each of the tube end storage chambers is formed so as to protrude from a side wall of the storage case and the partition wall inside each of the tube end storage chambers , and is provided with a plurality of support projection plates that support the tube ends of the cathode tubes. An illuminating device characterized in that a tube end of the cathode tube supported by a supporting projection plate and the partition wall is substantially surrounded planarly through an air layer.   The lighting device according to claim 1, wherein a rubber cover is attached to each end portion of the cathode tube accommodated in the tube end accommodating chamber. 3. The tube end accommodating chamber is provided with a plurality of supporting projection plates that contact the rubber cover attached to each end of the cathode tube and support the cathode tube, respectively. The lighting device described in 1.   The lighting device according to claim 1, wherein a cover member that substantially shields the chamber is covered in the tube end accommodation chamber.

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