JP2580539Y2 - Film heater - Google Patents

Description

[Detailed description of the invention]

[0001]

The present invention relates to, for example, a liquid crystal television,
Cold cathode discharge tubes (for example, fluorescent lamps) incorporated in various liquid crystal display devices and used as backlights,
The present invention relates to a film heater mounted on the outer surface of a cold cathode discharge tube bent into a letter shape or a W shape, and in particular, while improving the heating efficiency and improving the rising characteristics of the cold cathode discharge tube,
The present invention relates to a cold cathode discharge tube capable of improving the attachment property to a bent portion.

2. Description of the Related Art A film heater mounted on the outer surface of a cold cathode discharge tube has, for example, a structure as shown in FIGS. The film heater shown here is mounted on a W-shaped cold cathode discharge tube. First, there is a base film 101, and this base film 101 is formed in a W shape according to the shape of the cold cathode discharge tube. And are formed with the same width (h) in all places. still,
As the base film 101, for example, PET film (polyester film), PEN film (polyethylene naphthalate film), polyimide film,
A polyphenylene sulfide film or the like is used.

[0003] A predetermined heater pattern 103 is provided on the base film 101. The heater pattern 103 is also formed in a W shape according to the shape of the cold cathode discharge tube, and two heater wires are extended along the base film 101. The width (h ') of the heater pattern 103 is constant over the entire length. The heater pattern 103 is obtained by, for example, etching a metal such as aluminum, nickel chrome, and austenitic stainless steel. An overcoat 105 is provided on the heater pattern 103. The above overcoat 1
As 05, for example, a laminate film is used. Note that whether or not to provide the overcoat 105 is optional.

An intermediate portion (the right side in the figure) of the W-shaped base film 101 is formed so as to protrude to form a connecting portion 107. On the connection portion 107, both ends of the heater pattern 103 are provided as connection terminal portions 111 and 109. A power supply (not shown) is electrically connected through these connection terminals 111 and 109. Then, the film heater having the above configuration is attached to a W-shaped cold cathode discharge tube (not shown). Generally, the film heater is attached to the back side of the cold cathode discharge tube, but in some cases, the front side of the cold cathode discharge tube, that is, the cold cathode discharge tube is used as a backlight of various liquid crystal display devices. In such a case, it may be attached to the surface of the cold cathode discharge tube on the liquid crystal display device side.

[0005] By attaching the film heater having the above structure to the cold cathode discharge tube, the cold cathode discharge tube is heated to improve its rising characteristics. In other words, by heating through the outer surface of the cold cathode discharge tube by a film heater, the evaporation of mercury sealed in the cold cathode discharge tube is promoted, and the rising of the luminous flux is promoted by rapidly increasing the water vapor pressure, Thereby, the time required for a stable lighting state, that is, the rising characteristic of the cold cathode discharge tube is improved.

[0006]

According to the above conventional configuration, there are the following problems. First, there is a problem that the heating efficiency by the film heater and, consequently, the rising characteristics of the cold cathode discharge tube are insufficient. That is, the width (h) of the base film 101 of the film heater is the same over the entire length, and is relatively small with respect to the outer diameter of the cold cathode discharge tube. The heater pattern 103 of the film heater is extended while being accommodated in the width of the base film 101, and is configured to heat the cold cathode discharge tube through a relatively small heating area. For this reason, the heat loss is large, the heating efficiency is poor, and it is insufficient to enhance the rising characteristics of the cold cathode discharge tube.
Of course, it is conceivable to increase the amount of heat generated by the film heater in order to increase the heating efficiency, but this would unnecessarily increase the cost.

[0007] Another problem is that the film heater has poor mounting properties at the bent portions of the cold-cathode discharge tube (points indicated by symbols A, B, C, and D in FIG. 5), and it is difficult to mount the film heater. At the same time, there is a problem that the heating efficiency is lowered even if a good mounting state cannot be obtained. That is, there is a difference in the degree of bending between the inside and the outside of the bent portion, and when the film heater is attached, not only the base film 101 but also the heater pattern 103 partially floats or wrinkles. In some cases, the adhesion of the film heater to the cold cathode discharge tube was impaired. In such a case, the cold cathode discharge tube cannot be heated uniformly,
In some cases, abnormal heat generation occurred locally.

The present invention has been made based on such a point, and the object is to increase the heating efficiency to improve the rising characteristics of the cold cathode discharge tube, and to improve the bending characteristics of the cold cathode discharge tube. It is an object of the present invention to provide a film heater capable of improving the workability of the mounting work and improving the adhesion to the cold cathode discharge tube to improve the heating efficiency by improving the mountability.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, a film heater according to the present invention is attached to a cold cathode discharge tube having a straight portion and a bent portion used as a backlight, in a predetermined pattern on a base film. In a film heater provided with a formed heater pattern,
In the straight portion of the cold cathode discharge tube, the width of the base film is increased so as to cover as many surfaces as possible of the cold cathode discharge tube, and each heater wire constituting the heater pattern there is divided into a plurality of portions. The film is arranged side by side in a state of being dispersed within a wide range of the width of the film, while the width of the base film is reduced so as to cover as few surfaces of the cold cathode discharge tube as possible at the bent portion of the cold cathode discharge tube, and It is characterized in that heater wires divided by a straight line portion are gathered and contained within a narrow range of the base film.

[0010]

The width of the base film is increased at the straight portion of the cold cathode discharge tube and reduced at the bent portion. That is,
The straight portion covers as many surfaces of the cold cathode discharge tube as possible, while the bent portion covers as few surfaces of the cold cathode discharge tube as possible. At the same time, in the linear portion, the heater wires of the heater pattern are divided into a plurality of pieces, and are dispersed and arranged in parallel within a wide range of the base film. In the bent portion, the heater wires divided by the linear portion are gathered and arranged within a narrow range of the base film. Therefore, the heating area can be increased in the linear portion, so that the heating efficiency can be increased, thereby improving the rising characteristics of the cold cathode discharge tube. Further, in the bent portion, the mountability of the film heater to the cold cathode discharge tube can be improved.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The configuration of the film heater according to the present embodiment will be described. First, there is a base film 1, which is formed in a substantially W shape according to the shape of a W-shaped cold cathode discharge tube (not shown). As the base film 1, for example, a PET film (polyester film), a PEN film (polyethylene naphthalate film), a polyimide film, a polyphenylene sulfide film, or the like is used. In addition, the width of the base film 1 is relatively large (H) at the straight portion and relatively small (H ′) at the bent portion. The width (H) of the linear portion is such a width as to cover the outer surface of the cold cathode discharge tube as much as possible, and specifically, for example,
The coverage of the outer periphery of the cold-cathode discharge tube is preferably 20% or more, but it naturally depends on the outer diameter of the cold-cathode discharge tube. On the other hand, the width (H ') of the bent portion is a width that covers the outer surface of the cold-cathode discharge tube as little as possible. Here, the range as small as possible means that the film heater can be easily attached when attaching the film heater to the cold-cathode discharge tube, and that a partially floating portion does not occur or wrinkles do not occur. Refers to the width. This naturally depends on the shape, outer shape, curvature and the like of the cold cathode discharge tube.

On the base film 1, a heater pattern 3 formed in a predetermined pattern is provided.
The heater pattern 3 is obtained by, for example, etching a metal such as aluminum, nickel chrome, and austenitic stainless steel. Also, in the heater pattern 3, in the linear portion, one heater wire 7, 9 is replaced by two heater wires 7a, 7b, 9a, 9 respectively.
The heater wires 7a, 7b, 9a, and 9b are extended at a predetermined pitch. On the other hand, in the bent portion, the two heater wires 7 and 9 are directly extended. In other words, the four heater wires 7a, 7b, 9a, 9b are installed in a state of being assembled into two heater wires 7, 9, respectively. FIGS. 2 and 3 show the linear portion and the bent portion, respectively.
Further, in the case of the present embodiment, when the heater wires 7 and 9 are divided into two, the width thereof is made just half. That is, if the width of the heater wires 7 and 9 is 2 mm,
The width of a, 7b, 9a, 9b is 1 mm. In this case, the resistance value before the division, that is, the heat value can be the same. The present invention is not limited to such a division. The widths W and W ′ of the heater pattern 3 formed on the base film 1 are appropriately set according to the width of the base film 1, but are preferably set with respect to the outer periphery of the cold cathode discharge tube of the base film 1. It is desirable to increase or decrease in such a manner as to be linked to the coverage ratio.

As described above, in the linear portion, the width (H) of the base film 1 is increased, and the heater lines 7 and 9 of the heater pattern 3 are divided into 4 as the width of the base film 1 increases. Heater wires 7a, 7b, 9a, 9
b, and arranged so as to be dispersed in a relatively wide width and arranged in parallel, the heating area is expanded by contacting the cold cathode discharge tube with as large a contact area as possible, thereby increasing the heating efficiency and thus the heating efficiency. This is for the purpose of improving the rising characteristics of the cold cathode discharge tube. That is, the heating efficiency is higher when heating is performed in a wide range than when heating is performed in a narrow range as in the related art, even if the heating value is the same. In addition, the width (H ′) of the base film 1 at the bent portion is reduced,
As the width of the base film 1 is reduced, the heater pattern 3 is assembled into the two heater wires 7 and 9 because of the adhesive property of the film heater to the cold cathode discharge tube at the bent portion ( This is for the purpose of enhancing wearability.

An overcoat 5 is provided on the heater pattern 3. As the overcoat 5, for example, a laminate film is used. still,
Whether or not to provide the overcoat 5 is optional.

The operation and effect will be described based on the above configuration. First, the heating efficiency was improved, and the rising characteristics of the cold cathode discharge tube were improved. This will be described based on experimental results. First, two types of a film heater according to the present embodiment and a conventional film heater were prepared. The film heater according to the present embodiment is obtained by etching a heater pattern 3 made of an aluminum foil having a thickness of 15 μm on a base film 1 made of a PET film having a thickness of 38 μm. Its resistance is 14.7Ω. The dimensions of each part are as shown in FIGS. On the other hand, a conventional film heater has a PE thickness of 38 μm.
On a base film 1 composed of a T film, a thickness of 15 μm
The heater pattern 3 made of an aluminum foil of m was etched, and its resistance was 14.7Ω. The dimensions of each part are as shown in FIG.

The above two types of film heaters have an outer diameter of 6 mm.
To a cold cathode discharge tube formed of a W-shaped fluorescent lamp through a double-sided adhesive tape. They are placed in a thermostat kept at a low temperature (0 ° C.). And after 30 minutes,
A DC voltage of 12 V is simultaneously applied to each of the film heaters, and the temperature of the linear portion of the cold cathode discharge tube is measured by a thermocouple. FIG. 4 shows the results. FIG. 4 is a characteristic diagram in which time (min) is plotted on the horizontal axis and temperature (° C.) is plotted on the vertical axis to show temperature characteristics. The upper line in the drawing is the case of the film heater according to the present embodiment, and the lower line in the drawing is the case of the film heater according to the conventional example. As is apparent from FIG. 4, when the film heater according to the present embodiment is attached, the temperature rises faster and the temperature rise is also higher.

In addition, the adhesive property of the bent portion to the cold cathode discharge tube was improved. This is because the width of the film heater at the bent portion was reduced. That is, the width (H ′) of the base film 1 at the bent portion is reduced,
In addition, the heater patterns 3 are also assembled into two pieces and are installed in a narrow area. Therefore, it can be easily attached to the cold cathode discharge tube when it is attached to the cold cathode discharge tube, and the occurrence of a partially floating portion or wrinkling is eliminated. Thereby, the adhesion of the film heater to the cold-cathode discharge tube is improved, so that the heating efficiency and, consequently, the rising characteristics of the cold-cathode discharge tube can be improved.

The present invention is not limited to the above embodiment. First, in the linear portion of the film heater shown in FIG. 1, one heater pattern may be divided into three or more heater patterns. Also, in the case of the one embodiment,
When the heater wire is divided into two, the width is halved, but the invention is not limited to this, and the heater wire may be divided into any width. Further, in the case of the above-described embodiment, the width and the interval of the heater wires 7 and 9 in the bent portion are not particularly described. Becomes possible, and thereby the adhesiveness can be further improved. In addition, the width of the heater wires 7 and 9 at the bent portion may be reduced, noting that the heat generation amount at the bent portion is reduced to some extent without much influence. Also in this case, the width of the base film 1 can be further reduced, thereby further improving the sticking property. Further, in the above-described embodiment, the film heater attached to the W-shaped cold cathode discharge tube has been described as an example, but the present invention can be similarly applied to a film heater attached to a cold cathode discharge tube of another shape. In addition, in the above-described embodiment, the position where the film heater is attached to the cold cathode discharge tube is not particularly described. However, if the film heater is attached to the front side of the cold cathode discharge tube, the heating efficiency can be improved. Of course, the light emitted from the cold-cathode discharge tube is dispersed by the heater wires divided into a plurality of portions at the linear portion, and a uniform luminance distribution can be obtained.

[0019]

As described in detail above, according to the film heater of the present invention, the heating efficiency can be increased and the rising characteristics of the object to be heated can be improved. Further, it is possible to improve the mountability of the film heater at the bent portion of the object to be heated.

[Brief description of the drawings]

FIG. 1 is a plan view of a film heater according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1, illustrating an embodiment of the present invention;

FIG. 3 is a cross-sectional view taken along the line III-III of FIG. 1, illustrating an embodiment of the present invention;

FIG. 4 is a characteristic diagram showing an experimental result in a diagram illustrating an embodiment of the present invention.

FIG. 5 is a plan view of a film heater showing a conventional example.

6 is a view showing a conventional example, and is a sectional view taken along the line VI-VI of FIG. 5;

[Brief description of reference numerals]

 DESCRIPTION OF SYMBOLS 1 Base film 3 Heater pattern 5 Overcoat 7 Heater wire 9 Heater wire 7a Heater wire 7b Heater wire 9a Heater wire 9b Heater wire

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) H01J 61/52 G09F 9/00 F21S 3/00 H05B 3/20 318 G02F 1/1335 530

Claims (1)

(57) [Scope of request for utility model registration] 1. A film heater comprising a heater pattern formed in a predetermined pattern on a base film and attached to a cold cathode discharge tube having a straight portion and a bent portion used as a backlight. In the straight portion of the tube, the width of the base film is increased so as to cover as many surfaces of the cold cathode discharge tube as possible, and each heater wire constituting the heater pattern there is divided into a plurality of portions to form a wide width of the base film. In the meantime, the width of the base film is reduced so as to cover as few surfaces of the cold cathode discharge tube as possible at the bent portion of the cold cathode discharge tube, and divided by the linear portion. A film heater characterized in that the heater wires are gathered and contained within a narrow width of the base film.