JP2013229185A - Lighting device, and liquid crystal display device as well as electronic equipment provided with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily prevent bending of a reflecting sheet and warping of a light guide plate.SOLUTION: A lighting device 100 is provided with: a light source 11; a light guide plate 12 in which light incident from a light source 11 is emitted from a light-emitting face; a reflecting sheet 14 arranged at a face opposite to the light-emitting face of the light guide plate 12; a bottom-face member 16 having protruded parts 16a arranged at parts of the reflecting sheet 14 opposite to the light guide plate 12, partially in contact with the reflecting sheet 14, and supporting a whole of the reflecting sheet 14; and a driver substrate 15 having a driving circuit for driving the light source 11. The driver substrate 15 is arranged in a space formed by the protruded parts 16a located between the reflecting sheet 14 and the bottom-face member 16.

Description

  The present invention relates to a lighting device, a liquid crystal display device including the lighting device, and an electronic apparatus.

  In recent years, portable electronic devices such as smartphones and tablet terminals are becoming widespread. Such portable electronic devices are required to be thinner and lighter, and development of a terminal that is inexpensive and easy to assemble has been in progress.

  For example, in Patent Document 1, a liquid crystal display device 1, a backlight device 2, and a driver substrate 3 having a backlight LED drive circuit are supported on a liquid crystal display frame 4, respectively, and attached to a device casing. A connection structure for electrically connecting a connection terminal portion of a backlight LED 2c provided at the rear portion of the light device 2 and the LED terminal portion provided at a rear portion of the driver board 3, wherein the connection terminal portion of the LED 2c There is described a substrate connection structure for a linear LED for backlight, wherein the LED terminal portion of the driver substrate 3 is electrically connected by a conduction contact 5 (see FIG. 11).

  According to the technique disclosed in Patent Document 1, electrical connection is made by the conductive contact 5, and a flexible substrate (FPC) is not required. As a result, the soldering operation between the linear LED and the flexible substrate is eliminated, and the number of man-hours is greatly reduced. Further, the skill level of soldering is not required.

  Further, since the flexible substrate is eliminated, a connection connector for electrically connecting the end of the flexible substrate to the driver substrate 3 becomes unnecessary in place of the conductive contact 5. For this reason, the thickness H of the device casing can be reduced by the amount that the connector for connection becomes unnecessary.

  Further, the conduction contact 5 is installed by being press-fitted into a storage portion provided at the rear portion of the liquid crystal display frame 4, so that attachment is simple and man-hours are reduced. Then, after that, the linear LED is also simply installed by inserting it into the liquid crystal display frame 4 from above, thereby reducing the number of steps. By using two connection terminals for the linear LED, the number of conductive contacts 5 is two, and the number of parts is reduced and the weight is reduced.

JP 2008-9047 A (published January 17, 2008)

  However, in Patent Document 1, the liquid crystal display device 1, the backlight device 2, and the driver substrate 3 having the backlight LED drive circuit are supported by the liquid crystal display frame body 4, respectively, and mounted on the device casing. The display device 1, the backlight device 2, and the driver substrate 3 are mounted in a stacked state by supporting the display device 1, the backlight device 2, and the driver substrate 3 on the liquid crystal display frame 4. Since the plate 2d is not supported on the entire surface by the driver substrate 3, the reflecting plate 2d is bent.

For example, in order to prevent the reflection plate 2d from being bent, it is assumed that the driver substrate 3 is made larger than necessary in accordance with the size of the liquid crystal display device. However, in this case, the weight of the entire device becomes heavy and space is wasted.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a lighting device capable of easily preventing the deflection of the reflection sheet and the warp of the light guide plate, and a liquid crystal display including the same. It is to provide an apparatus and an electronic device.

  In order to solve the above-described problems, an illumination device of the present invention includes a light source, a light guide plate from which light incident from the light source is emitted from a light emission surface, and a light emission surface opposite to the light emission surface of the light guide plate. A bottom surface member that has a protrusion that is disposed on the side opposite to the light guide plate arrangement side of the reflection sheet and that partially protrudes from the reflection sheet to support the reflection sheet; A driver board having a drive circuit for driving the light source, and the driver board is provided in a space formed by the protrusions positioned between the reflection sheet and the bottom member.

  According to said structure, since the reflective sheet is supported by the projection part of a bottom face member, it becomes possible to suppress the bending of the reflective sheet and the curvature of a light-guide plate which arise under the influence of the expansion-contraction by gravity or a heat | fever. Therefore, it is possible to provide an illumination device that can easily prevent the reflection sheet from bending and the light guide plate from warping.

  Further, in the conventional configuration, a backlight chassis is provided on the back surface of the light guide plate in order to suppress warpage and deflection. However, according to the above configuration, the backlight chassis is not necessary because the bottom member functions as the backlight chassis. As a result, the entire apparatus can be reduced in thickness and weight.

  In addition, since there is a space corresponding to the size of the protrusion between the bottom member and the reflection sheet, the driver board can be accommodated, and the entire apparatus can be thinned.

  Moreover, the illuminating device of this invention WHEREIN: The said protrusion part supports the area | region corresponding to the light-projection surface of the said light-guide plate in the said reflection sheet.

  According to said structure, it becomes possible to suppress the optical nonuniformity which arises by the bending of the reflection sheet in the light emission area | region of a light-guide plate, and can provide the illuminating device excellent in the brightness | luminance and chromaticity uniformity.

  In the illumination device of the present invention, the protrusion supports a region of the reflection sheet corresponding to the vicinity of the light incident part for the light guide plate to take in light from the light source.

  In the vicinity of the light source, the light guide plate and the reflection sheet are likely to warp due to heat generated from the light source. As a result, a positional deviation between the light guide plate and the light source in the vicinity of the light incident portion occurs, causing a decrease in optical coupling efficiency. According to the above configuration, since the light guide plate and the reflection sheet in the vicinity of the light source are supported by the protrusions of the bottom surface member, the light guide plate and the reflection sheet can be prevented from warping, and the light guide plate and the light source in the vicinity of the light incident portion. It is possible to prevent the occurrence of positional misalignment. Therefore, it is possible to provide a lighting device with high light utilization efficiency.

  In the lighting device of the present invention, a power storage device for supplying power to the device main body is disposed in the space between the reflection sheet and the bottom member.

  According to said structure, the space between a plate-shaped member and a reflective sheet can be utilized effectively.

  In the lighting device of the present invention, at least a portion of the protrusion that contacts the reflection sheet is formed of an elastic member, and the other portion of the protrusion is formed of the same material as the bottom member.

  According to the above configuration, by fixing the elastic member in a compressed state by applying pressure to the bottom surface member, the elastic member expands and contracts even when the entire device is twisted or deformed, and is always in contact with the reflection sheet Can be maintained. This makes it possible to provide a high-quality lighting device that can maintain an optically uniform state even when the entire device is deformed.

  Moreover, the illuminating device of this invention is further equipped with the housing | casing arrange | positioned along the outer periphery of the said bottom surface member, and the said housing | casing protrudes rather than the light-projection surface of the said light-guide plate.

  According to said structure, since it becomes possible to adhere | attach the protection member for protecting a light guide plate on the upper surface of the housing | casing which protruded, the damage | wound and dirt of a light guide plate can be prevented. Thereby, a highly durable lighting device can be provided.

  In order to solve the above problems, a liquid crystal display device of the present invention includes the above-described illumination device and a liquid crystal panel disposed on the light emitting surface side of the light guide plate.

  According to said structure, the liquid crystal display device which can prevent easily the bending of a reflection sheet and the curvature of a light-guide plate can be provided.

  Furthermore, an electronic apparatus according to the present invention includes the above-described lighting device.

  According to said structure, the electronic device which can prevent easily the bending of a reflection sheet and the curvature of a light-guide plate can be provided.

  The present invention has an effect that the deflection of the reflection sheet and the warpage of the light guide plate can be easily prevented.

It is a disassembled perspective view which shows an example of the principal part structure of the illuminating device in this Embodiment. It is a figure which shows the 1st structure of a projection part. It is a figure which shows the 2nd structure of a projection part. It is a disassembled perspective view which shows an example of the principal part structure of the illuminating device in a 1st modification. It is a disassembled perspective view which shows an example of the principal part structure of the illuminating device in a 2nd modification. It is sectional drawing of the principal part structure of the illuminating device in a 2nd modification. It is a disassembled perspective view which shows an example of a structure of a liquid crystal display device. It is sectional drawing which shows an example of a structure of a liquid crystal display device. It is a figure which shows two-dimensional luminance distribution when an illuminating device is turned on. It is a figure which shows the luminance distribution in each upper and lower light-guide plates shown in FIG. It is a disassembled perspective view which shows the electronic device provided with the conventional illuminating device.

  Embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

[Configuration of lighting device]
FIG. 1 is an exploded perspective view showing an example of a main configuration of the lighting apparatus according to the present embodiment. As shown in FIG. 1, the lighting device 100 includes a light source 11, a light guide plate 12, a frame 13 for supporting them, a reflection sheet 14, and a bottom member 16 on which a driver substrate 15 is provided. .

  The light guide plate 12 becomes a planar light source when light from the light source 11 is introduced therein. The light guide plate 12 is preferably an injection molded product or an extrusion molded product of a transparent plastic member typified by acrylic (PMMA). In the case of an injection-molded product, a prism shape for enhancing the light extraction efficiency can be collectively formed on the light emission pattern or the opposite surface. In addition, it is possible to increase the optical coupling efficiency by partially increasing the thickness of the light incident part for taking in the light emitted from the light source 11 and gradually decreasing the thickness as it approaches the light emission surface. .

  Moreover, in an extrusion molded product, it is possible to transfer a light emission pattern or a prism shape by roll transfer. However, the light emission pattern is not limited to transfer by a mold, and may be formed by screen printing, ink jet printing, or laser processing.

  As the light source 11, it can be set as the structure by which several LED was arrange | positioned at the edge part of the light-guide plate 12 on the line. In addition, since LED can be reduced in size and thickness, in order to reduce the thickness of the apparatus, the light source is preferably an LED, and the case has been described as an example. However, the light source 11 is not limited to the LED, and may be a cathode ray tube or a similar light source.

  The reflection sheet 14 is disposed on the back surface, which is the surface opposite to the light emitting surface of the light guide plate 12, and reflects the light leaking from the back surface of the light guide plate 12 toward the light guide plate 12. The reflection sheet 14 has an area equivalent to that of the light guide plate 12.

  The frame 13 supports the light source 11 and the light guide plate 12, and the portion of the frame 13 that covers the three sides other than the light incident portion where the light source 11 is disposed is preferably a highly reflective member. For example, the material of the frame 13 is white PC resin (polycarbonate resin).

  The bottom member 16 is a bottom housing (back housing) of the lighting device 100 and is preferably an injection-molded product of a highly rigid resin material. For example, the material is ABS resin (acrylonitrile / butadiene / styrene copolymer synthetic resin) or PC resin (polycarbonate resin) containing glass filler or carbon filler. If the rigidity of the bottom member 16 is high, the thickness can be reduced accordingly, so that the entire apparatus can be thinned.

  The bottom surface member 16 includes a plurality of protrusions 16 a and a plate-like member 16 b provided with the protrusions 16 a and is disposed on the back surface of the reflection sheet 14. The plurality of projecting portions 16 a support the reflective sheet 14 from the back side by contacting the reflective sheet 14 with the upper ends thereof.

  Further, the plurality of protrusions 16 a are provided in a distributed manner in a region corresponding to the light emitting region of the light guide plate 12 on the plate-like member 16 b. Thereby, the reflection sheet 14 can be supported from the back without bending.

  In addition, in FIG. 1, although the linear protrusion extended in parallel with respect to the light source 11 is illustrated as a shape of the projection part 16a, it is not restricted to this shape. For example, a columnar shape or a frame shape may be used as long as the reflective sheet 14 is supported in a distributed manner from the back surface. When the shape of the protrusion 16a is a columnar shape, the protrusion 16a may be arranged parallel to the light source 11.

Thus, a plurality of protrusions 16a are formed dispersed on the plate-like member 16b, so that a space is formed between the plate-like member 16b and the reflection sheet 14, and the driver substrate 15 is placed in this space. Be placed. Therefore, the plurality of protrusions 16a are dispersed so as to ensure a space in which the driver board 15 can be arranged. Further, the height of the protrusion 16 a is set higher than the thickness of the driver substrate 15. For this reason, the driver board | substrate 15 is arrange | positioned on the plate-shaped member 16b, without contact | abutting to the reflective sheet 14. FIG.

  The driver board 15 is preferably as thin as possible. If the driver board 15 is thinned, the height of the space in which the driver board 15 is accommodated can be reduced, so that the entire apparatus can be thinned. In addition, since the height of the protrusion 16a provided on the bottom member 16 can be reduced and the shape can be easily formed, the degree of freedom in designing the material to be used, the mold structure, and the like is increased.

  Further, among the plurality of protrusions 16a, the one that supports the reflection sheet 14 on the end face side of the light guide plate 12 on which the light source 11 is arranged is the plate member 16b on the light guide plate 12 on which the light source 11 is arranged. It is preferable to be provided in the vicinity of the end face. The warp generation region of the light guide plate 12 due to the light source 11 varies depending on the thickness, size, material, etc. of the light guide plate 12 or the amount of heat generated by the light source. Warpage can be prevented or suppressed by providing the protrusion 16a within a range of −10 mm to 10 mm in a direction perpendicular to the end face. However,-(negative) direction shows the direction which goes to the light source 11 at right angles from the end surface of the light-guide plate 12, and the protrusion part 16a is the state arrange | positioned ranging over the light source 11 and the light-guide plate 12 in this case. Thereby, in the reflection sheet 14, since the projection part 16a supports the vicinity of the position where the light source 11 is arrange | positioned, the curvature of the light-guide plate 12 and the reflection sheet 14 by the heat_generation | fever of the light source 11 can be reduced. Further, by reducing the warpage of the light guide plate 12, it is possible to suppress a decrease in optical coupling efficiency caused by a positional deviation between the light guide plate 12 and the light source 11. Therefore, it is possible to provide a lighting device with high light use efficiency.

  Further, as shown in FIG. 2, the protrusion 16 a is preferably configured such that a portion in contact with the reflection sheet 14 is formed of an elastic member 16 c such as foamed urethane. Thus, by pressing the bottom surface member 16 and fixing the elastic member 16c in a compressed state, even when the entire device is twisted or deformed, the elastic member 16c expands and contracts and always contacts the reflective sheet 14 Can be maintained.

  Here, the configuration in which the protruding portion 16a includes the elastic member 16c has been described as an example. However, as illustrated in FIG. 3, the protruding portion 16a in a state where the elastic member 16c is not disposed directly contacts the reflective sheet 14. You may touch.

  The four sides of the reflection sheet 14 are preferably bonded to the lower part of the four sides of the frame 13. Thereby, since the deflection amount of the reflection sheet 14 when there is no support by the projection part 16a provided in the bottom face member 16 can be made as small as possible, it is possible to make the number of the projection parts 16a provided minimum necessary. .

<First Modification>
FIG. 4 is an exploded perspective view illustrating an example of a main part configuration of the illumination device according to the first modification. 4A is a charging device (power storage device) 21 that supplies power to the light source 11 in a space between the plate-like member 16b and the reflection sheet 14 as compared to the lighting device 100 shown in FIG. Is different. Thereby, the space between the plate-like member 16b and the reflection sheet 14 can be effectively utilized.

The charging device 21 is preferably made as thin as possible, like the driver board 15. If the charging device 21 is thinned, the height of the space in which the charging device 21 is housed can be reduced, so that the entire device can be thinned. In addition, the height of the protrusions 16a provided on the bottom member 16 can be reduced, and the shape can be easily formed. Therefore, the degree of freedom in designing the material to be used, the mold structure, and the like is increased.

<Second Modification>
FIG. 5 is an exploded perspective view showing an example of a main configuration of the illumination device according to the second modification. FIG. 6 is a cross-sectional view of the main configuration of the illumination device according to the second modification. As shown in FIGS. 5 and 6, the illumination device 100B is different from the illumination device 100A shown in FIG. The casing 31 is disposed along the outer periphery of the plate-like member 16 b and has a height that protrudes from the light emitting surface of the light guide plate 12. As a result, a protective member for protecting the light emitting surface of the light guide plate 12 can be adhered to the upper surface of the protruding housing 31, so that the light guide plate 12 can be prevented from being scratched and soiled, and a high quality lighting device can be obtained. It becomes possible to provide.

  Further, as shown in FIG. 8, an optical sheet 51 such as a prism sheet, a microlens sheet, or a light diffusion sheet may be disposed on the light emitting surface side of the light guide plate 12. In this case, the frame 13 may be provided with the casing 31 that supports the light guide plate 12, the light source 11, and the optical sheet 51 and protrudes from the optical sheet 51.

The casing 31 is preferably a highly rigid one represented by, for example, CFRP (Carbon Fiber Reinforced Plastic). Thereby, since it becomes possible to raise the rigidity of the whole apparatus, it becomes possible to provide a highly durable illuminating device. Further, the housing 31 may be molded together with the bottom surface member 16.

  As described above, the illumination device 100 of the present invention includes the light source 11, the light guide plate 12 from which the light incident from the light source 11 is emitted from the light exit surface, and the opposite side of the light exit surface of the light guide plate 12. A bottom surface having a reflection sheet 14 disposed on the opposite side of the reflection sheet 14 to the side where the light guide plate 12 is disposed, and a protrusion 16a that partially contacts the reflection sheet 14 and supports the entire reflection sheet 14 A member 16 and a driver board 15 having a drive circuit for driving the light source 11 are provided. The driver board 15 is provided in a space formed by a protrusion 16 a located between the reflection sheet 14 and the bottom surface member 16. Yes.

  For this reason, since the reflection sheet 14 is supported by the protrusions 16a of the bottom surface member 16, it is possible to suppress the deflection of the reflection sheet 14 and the warp of the light guide plate 12 caused by the influence of expansion and contraction due to gravity and heat. Therefore, the deflection of the reflection sheet 14 and the warp of the light guide plate 12 can be easily prevented. In addition, it is possible to suppress optical unevenness caused by the deflection of the reflection sheet 14 and the warp of the light guide plate 12, and an illuminating device having excellent luminance and chromaticity uniformity can be provided.

  In the conventional configuration, a backlight chassis is provided on the back surface of the light guide plate in order to suppress warpage and deflection. However, according to the configuration of the illumination device 100 of the present invention, the backlight chassis is unnecessary, It also has the effect of reducing the overall thickness and weight.

  Furthermore, the illuminating device 100 of this invention is provided with the thin driver board | substrate 15 in the space between the reflective sheet 14 and the plate-shaped member 16b, without making it unnecessarily large. For this reason, it is possible to manufacture a lighting device at low cost.

In addition, you may make it provide the illuminating device 100,100A, 100B demonstrated above in a liquid crystal display device as a backlight. In this case, as illustrated in FIG. 7, a liquid crystal panel 41 is provided on the light emitting surface side of the light guide plate 12, and a prism sheet or a microlens sheet is provided between the light guide plate 12 and the liquid crystal panel 41 as necessary. An optical sheet 51 such as a light diffusion sheet may be inserted.

  Moreover, in the structure with which a liquid crystal display device is equipped as a backlight, the housing | casing 31 arrange | positioned along the outer periphery of the plate-shaped member 16b has the height which added the thickness of the liquid crystal panel 41, and is the structure of an illuminating device. What is necessary is just to set it as the structure which covers the circumference | surroundings of the liquid crystal panel 41 with a bottom housing | casing.

[Presence of protrusions and uneven brightness]
Next, the state of luminance unevenness due to the presence or absence of the protrusion 16a will be described with reference to FIGS. FIG. 9 is a diagram illustrating a two-dimensional luminance distribution when the lighting device is turned on. The illumination device 100 has a configuration in which the upper half of the solid line passing through the center of the light source has the above-described protrusion 16a, and the lower half of the solid line has a configuration excluding the protrusion 16a, and visually compares the two-dimensional luminance distributions above and below. It is easy to do. In the figure, the light guide plate 12 and the light source 11 are shown for convenience.

  Referring to the two-dimensional luminance distribution in the lower half light guide plate 12, it can be seen that the luminance in the vicinity of the light source 11 decreases and luminance unevenness occurs. On the other hand, referring to the two-dimensional luminance distribution in the upper half light guide plate 12, it can be seen that luminance unevenness does not occur.

  FIG. 10 is a diagram showing the luminance distribution in the upper and lower light guide plates shown in FIG. In contrast to the luminance distribution of the A-A ′ line in the upper half light guide plate 12, the luminance distribution of the B-B ′ line in the lower half light guide plate 12 has a lower luminance near the light incident portion. This decrease in luminance is due to a decrease in optical coupling efficiency due to the deflection of the reflection sheet 14 caused by the absence of the protrusion 16a on the back surface of the reflection sheet 14 and the warpage of the light guide plate 12 due to the heat generated by the light source 11. is there. Actually, the decrease in optical coupling efficiency was 26.6%. At this time, not only the data but also the luminance unevenness is visually recognized, so that the quality of the lighting device is significantly lowered. On the other hand, luminance unevenness was not visually recognized in the upper half light guide plate 12.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  The illuminating device of the present invention can be used as an electronic device such as a smartphone or a tablet terminal or as a planar light source for illumination, and can be suitably used particularly for an image display device such as a liquid crystal display device.

DESCRIPTION OF SYMBOLS 11 Light source 12 Light guide plate 13 Frame 14 Reflective sheet 15 Driver board 16 Bottom member 16a Protrusion part 16b Plate-like member 16c Elastic member 21 Charging device (power storage device)
31 Housing 41 Liquid crystal panel 51 Optical sheet 100, 100A, 100B Illumination device

Claims (8)

A light source;
A light guide plate from which light incident from the light source is emitted from a light exit surface;
A reflective sheet disposed on the side opposite to the light exit surface of the light guide plate;
A bottom surface member that is disposed on the side opposite to the light guide plate arrangement side of the reflection sheet and has a protrusion that partially contacts the reflection sheet and supports the entire reflection sheet;
A driver board having a drive circuit for driving the light source,
The lighting device according to claim 1, wherein the driver substrate is provided in a space formed by the protrusions positioned between the reflection sheet and the bottom member.   The lighting device according to claim 1, wherein the protrusion supports a region corresponding to a light emitting surface of the light guide plate in the reflection sheet.   3. The illumination device according to claim 1, wherein the protrusion supports a region corresponding to a vicinity of a light incident part for the light guide plate to capture light from the light source in the reflection sheet. .   The lighting device according to claim 1, wherein a power storage device for supplying electric power to the device main body is disposed in a space between the reflection sheet and the bottom surface member.   The lighting device according to any one of claims 1 to 4, wherein at least a portion of the protrusion that is in contact with the reflection sheet is formed of an elastic member. A housing disposed along the outer periphery of the bottom member;
The illuminating device according to claim 1, wherein the casing protrudes from a light exit surface of the light guide plate.   A liquid crystal display device comprising: the illumination device according to claim 1; and a liquid crystal panel disposed on a light emitting surface side of the light guide plate.   An electronic apparatus comprising the lighting device according to claim 1.

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