JP2005123103A - Light source, backlight device and liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate unevenness in coating or brightness of a light source to improve reflection performance, brightness as well as assembly efficiency. <P>SOLUTION: In a light emitting element unit equipped with light emitting elements LED1, all the surfaces except for the LED1s are covered with a coating 6 having the optical reflection property. The light emitting element unit includes LED1s aligned on a narrow strip of a substrate 5 at a regular intervals in the direction of the longer side. In the coating 6, holes 3 shaped as the LED1 are formed at the positions corresponding to the LED1s. The coating 6 has a shape of approximately straight tube and is made of a heat shrinkable resin so that the light emitting element unit is coated with the coating 6 by shrinking the coating 6 after being inserted into it. A backlight device comprises theses light sources, a light controlling device which drives and controls the light sources, and a housing which holds the light sources and includes a reflection plate for reflecting the light emitted from the light sources. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a light source device using a light-emitting diode element, a backlight device using the light source device, and a liquid crystal display device using the backlight device.

In general, a light source device using a light emitting diode element (hereinafter referred to as an LED) is used in many devices. In these devices, there is an “LED light reflection coating substrate” described in Patent Document 1 as a technique for using the luminance of the LED without waste. This is to reduce the number of man-hours for LED reflector processing and LED mounting by applying white paint to the LED mounting part of the printed circuit board and reflecting the light of the mounted LED to prevent light loss to the printed circuit board side. This is a technology aimed at. FIG. 3 is an exploded perspective view showing the “LED light reflection coating substrate”. When the illustrated LED 1 emits light, the reflection plate 2 reflects light from the LED 1 to prevent light loss to the printed circuit board 5. To do. As a result, it is possible to reduce the number of man-hours for forming the reflector 2 and the number of steps for mounting the LED 1.
Japanese Utility Model Publication No. 1-152405

  However, the above-mentioned “LED light reflection coated substrate” has a problem of lowering quality such as coating unevenness and color deterioration due to paint deterioration when processing such as white coating is performed. In particular, when the above-mentioned substrate is used in a backlight device, uniform and sufficient luminance is required to improve the image quality. However, it takes time and effort to coat the substrate so that luminance unevenness does not occur, and costs increase. There was a problem to do. Accordingly, an object of the present invention is to propose a light source device, a backlight device, and a liquid crystal display device that have no luminance unevenness and can increase the luminance and that do not require processing costs.

  In order to solve the above-described problems, in the light source device according to the present invention, a portion excluding the light emitting element of the light emitting element unit on which the light emitting element is mounted is covered with a covering having optical reflection characteristics. In addition, a portion of the light emitting element unit on which the light emitting element is mounted except the light emitting element is covered with a heat shrinkable covering body having at least a surface portion having optical reflection characteristics. Here, a hole corresponding to the shape of the light emitting element is formed at a position corresponding to the light emitting element of the covering. In addition, the light emitting element unit has the light emitting element mounted at an appropriate interval in the longitudinal direction on an elongated substrate, and the covering is formed of a resin having a substantially straight tube shape and at least a heat shrinkability in the circumferential direction. Then, after the light emitting element unit is inserted into the covering, the covering is heated and contracted to cover.

Furthermore, the light emitting element unit has the light emitting element mounted on the flat substrate in both vertical and horizontal directions at appropriate intervals, and the covering has a substantially bag shape covering the light emitting element unit and heat shrinkability in both vertical and horizontal directions. After the light emitting element unit is inserted into the covering body, the covering body is heated and contracted to cover the light emitting element unit. Note that a light-emitting diode element can be used as the light-emitting element. A light source device having these configurations, a light control unit that drives and controls the light source device, and a housing that includes a reflector that supports the light source device and reflects light emitted from the light source device forward. A backlight device is configured. Further, a liquid crystal panel is arranged in front of the backlight device to constitute a liquid crystal display device.

  As described above, according to the present invention, the light emitting element unit composed of the light emitting diode element is mounted on the substrate at an appropriate interval, and further, by the covering made of the resin having optical reflection characteristics and heat shrinkability. By covering the substrate portion, it is possible to manufacture a light source device free from unevenness in luminance and deterioration in luminance as compared with the case where coating is used for the reflecting portion. In addition, a backlight device using this light source device can provide a stable backlight device with uniform luminance and no luminance deterioration. Further, a liquid crystal display device using this backlight device can obtain a liquid crystal display device with stable image quality.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing a configuration of a light source device according to the present invention. In the figure, reference numeral 1 denotes an LED which is a light emitting element, which is mounted on one side of an elongated printed board 5 at substantially equal intervals to constitute a light emitting element unit, that is, an LED unit. The outer periphery of the printed circuit board 5 is covered with a white covering 6 having heat shrinkage characteristics and light shielding properties. In addition, the hole 3 matched with the external shape of LED1 is formed in the part in which LED1 of the covering body 6 is located, and LED1 is exposed to the outer side of the covering body 6. FIG. Moreover, since the covering 6 covers the printed circuit board 5 in a heated and contracted state, the covering 6 has a certain tension and tightens the printed circuit board 5 to increase the rigidity of the printed circuit board 5. . With this configuration, when the LED 1 is driven to emit light, the light emitted forward advances as it is, and the light emitted obliquely rearward is reflected by the cover 6 and sent forward.

  FIG. 2 is an explanatory view schematically showing an assembly procedure of the light source device of FIG. First, the rectangular columnar printed circuit board 5 has LEDs 1 mounted on one surface thereof at substantially equal intervals. A resin-made covering body 6 having a heat shrink characteristic having a substantially single tube shape having an inner diameter sufficiently larger than the cross-sectional maximum dimension of the printed board 5 on which the LED 1 is mounted is prepared. The covering 6 has at least a circumferential heat shrinkage characteristic, and the outside thereof is white and has an optical reflection characteristic. The circumferential direction here refers to the direction in which the substantially circular shape, which is the cross section of the tube when the covering has a tube shape, reduces the size of the circle.

Holes 3 corresponding to the outer peripheral shape of the LED 1 are opened at the positions of the LED 1 in a state where the printed board 5 is inserted into the covering 6. Next, the printed circuit board 5 is inserted inside the covering 6 to align the hole 3 with the LED 1. With this state maintained, the covering 6 is heated and contracted by blowing hot air on the covering 6 or the like. When the covering body 6 contracts, the covering body 6 holds the periphery of the printed circuit board 5 while the LED 1 protrudes from the hole 3 to complete the light source device. Compared to a light source device in which the reflective part is formed by painting, this light source device reduces the man-hours during assembly, improves the reflective performance of the surroundings, reduces brightness unevenness, and reduces deterioration of brightness over time. Characteristics are obtained.

  The light source device shown in FIGS. 1 and 2 can be used as a light source of a backlight device by arranging a plurality of the light source devices in parallel. In that case, a light source device with stable luminance without luminance unevenness is obtained. It is done. Although not shown, the light emitting element unit is formed by mounting LEDs at appropriate intervals in both vertical and horizontal directions on a flat substrate, and the light emitting element unit is formed of a resin having heat shrinkability in both vertical and horizontal directions. At the same time, the light source device can be obtained by inserting the cover into a cover in which a hole is formed at the position of the LED and heating and contracting the cover. Since this light source device has no luminance unevenness and has a stable luminance, it can be used as it is as a light source of a backlight device.

Furthermore, it is also possible to construct a liquid crystal television using these backlight devices thus obtained as a backlight of a liquid crystal display device. In that case, a liquid crystal television with stable image quality such as brightness can be obtained. Further, when the light source device according to the present invention is used as a backlight device of a liquid crystal display device, the light use efficiency is improved, and the power consumption of the device can be reduced. In the illustrated example, a white so-called heat-shrinkable tube is used as the covering 6, but a transparent heat-shrinkable tube can also be used. In that case, the surface of the printed circuit board 5 is set as a white or mirror-like reflective surface. In addition to the chip type, an LED lamp or the like can also be used for the LED 1, and there is no limitation on the type of device, its color development, and the like. Furthermore, the material of the printed circuit board 5 is not particularly limited.

  INDUSTRIAL APPLICABILITY The present invention can be used for backlight devices for various display devices using a linear or planar light source device, particularly for liquid crystal display devices such as liquid crystal televisions.

It is a perspective view which shows the structure of the light source device which concerns on this invention. It is explanatory drawing which shows the assembly procedure of the light source device of FIG. 1 typically. It is a disassembled perspective view which shows a prior art example.

Explanation of symbols

1 LED
3 hole 5 printed circuit board 6 covering

Claims (10)

A light source device, wherein a portion of a light emitting element unit on which a light emitting element is mounted, excluding the light emitting element, is covered with a covering having optical reflection characteristics. A light source device characterized in that at least a surface portion of a light emitting element unit on which a light emitting element is mounted, excluding the light emitting element, is covered with a heat shrinkable covering having optical reflection characteristics. The light source device according to claim 1 or 2,
A light source device, wherein a hole corresponding to the shape of the light emitting element is formed at a position corresponding to the light emitting element of the covering. The light source device according to claim 1,
The light-emitting element unit has the light-emitting element mounted at appropriate intervals in the longitudinal direction on an elongated substrate. The light source device according to claim 4,
The covering body is formed of a resin having a substantially straight pipe shape and having at least a circumferential heat shrinkability, and the light emitting element unit is inserted into the covering body, and then the covering body is heated and contracted to be covered. A light source device. The light source device according to claim 1,
The light emitting device unit is characterized in that the light emitting device is mounted at appropriate intervals in both vertical and horizontal directions on a flat substrate.
The light source device according to claim 6,
The covering has a substantially bag shape covering the light emitting element unit and is formed of a resin having heat shrinkability in both vertical and horizontal directions. After the light emitting element unit is inserted into the covering, the covering is heated and contracted to cover the light emitting element unit. A light source device characterized by that. The light source device according to any one of claims 1 to 7,
A light source device using a light emitting diode element as the light emitting element. A light source device according to any one of claims 1 to 8, a light control means for driving and controlling the light source device, and a reflector that supports the light source device and reflects light emitted from the light source device forward. A backlight device comprising a housing provided with the backlight device. A liquid crystal display device comprising a liquid crystal panel arranged in front of the backlight device according to claim 9.

Images