JP2004193002A - Area light source device and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device and an area light source device used for the display device, capable of sufficiently radiating heat of an LED with a simple structure of which, a thin thickness is required. <P>SOLUTION: The area light source device comprises a point light source mounted on a base plate; a heat radiation plate having at least one hole formed thereon, equipped with a blower blowing air to a surface supporting a surface opposite to the surface on which the point light source on a base plate is mounted; and a blowing direction changing means making the air blown toward the supporting surface turn toward the back side of the supporting surface of the heat radiation plate at the hole. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a planar light source device. More specifically, the present invention relates to a planar light source device and a display device arranged in a display device having a plurality of light emitting diode chips on a substrate.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a planar light source device in which a number of light emitting diodes (hereinafter, referred to as LEDs) are arranged has been used for a backlight of a display device, illumination of a microscope, and the like.
[0003]
In the surface light source device (illumination device) as described above, the heat radiation of the LED is radiated to the radiator through the lead and the heat radiation sheet, and the wind of forced air cooling is applied to the lead together with the body to radiate the heat ( For example, see Patent Document 1).
[0004]
[Patent Document 1]
JP-A-10-133608 (pages 3 and 4, FIG. 2)
[0005]
[Problems to be solved by the invention]
When the planar light source device in which the LEDs are arranged is configured as described above, the luminous efficiency of the LEDs themselves decreases and the durability of the junction part deteriorates as the heat generation of the LEDs increases. For example, in the planar light source device (illumination device) described in Patent Literature 1, the heat of the leads is radiated by a radiator sheet and a radiator provided on the back of a printed circuit board on which LEDs are provided. Furthermore, in order to dissipate the heat transmitted from the leads, the air blown by the fan located on the back is sent through the fins, a part of the wind is discharged, and a part is further transmitted to the surface of the printed circuit board, and the body and the surface of the printed circuit board So that it also flows. However, in the planar light source device (illumination device) having this configuration, since the wind blown from the fan radiates the heat radiation sheet through the fins and the radiator, the heat radiation effect of the heat radiation sheet is not sufficient. For this reason, many components constitute the heat radiating means for radiating the heat radiating sheet, but it is not possible to manufacture a thin display device which is recently required for a display device.
[0006]
The present invention has been made in order to solve such a problem, and provides a display device that can sufficiently radiate LEDs with a simple structure and that is required to be thin and a planar light source device installed in the display device. Things.
[0007]
[Means for Solving the Problems]
The planar light source device of the present invention,
A point light source mounted on a substrate,
A heat sink having a blower for blowing air to a support surface having at least one hole formed therein and supporting a surface of the substrate opposite to a surface on which the point light source is mounted.
A planar light source device comprising:
It is characterized in that it is provided with wind direction changing means for directing the air blown to the support surface in the hole to the back surface of the support surface of the heat sink.
[0008]
Further, the display device of the present invention,
A display panel;
A point light source mounted on a substrate disposed on a surface opposite to the display surface of the display panel,
A heat sink that supports a surface of the substrate opposite to the surface on which the point light source is mounted, and has at least one hole;
A frame formed so as to surround the display panel and the heat sink, and having a blower that blows air through the at least one hole on a support surface of the heat sink.
A display device comprising:
The at least one hole is provided with wind direction changing means for directing the air blown to the support surface of the heat sink to the back surface of the support surface.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiment 1
Hereinafter, the structure of the planar light source device according to the embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view of a planar light source device according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along line AA of FIG. In the drawing, 1 is an LED, 2 is a substrate such as MCPCB, 3 is a first reflector, 4 is a first light guide plate, 5 is a second reflector, 6 is a rear metal, 7 is a mold frame, 8 is a second light guide plate, 9 Is a reflection sheet, 10 is an optical sheet, 11 is a radiator plate, 12 is a blower, and the surface light source device is configured as described above. Reference numeral 13 denotes a liquid crystal panel, which forms a liquid crystal display device by arranging a planar light source device on a surface opposite to a display surface.
[0010]
The LED unit 31 in which the LED 1 is mounted on the substrate 2 is supported by the heat radiating plate 11. A first reflector 3 whose inner surface is mirror-finished is arranged near the LED 1 so that light emitted from the LED 1 is incident on the first light guide plate 4. The first light guide plate 4 receives a plurality of lights generated from the LED 1 from the incident surface 4a, mixes the light while repeating total reflection on the upper, lower, left and right surfaces, generates uniform white, and emits light that faces the incident surface 4a. The light exits from the surface 4b. The surface of the light guide plate used in the present invention must be mirror-finished in order to make total reflection, and the bending factor must be n = 1.41 or more. As a material of the first light guide plate 4, a light and inexpensive methacrylic resin (PMMA), a polycarbonate resin, or the like is mainly used. The light emitted from the emission surface 4b of the first light guide plate 4 is arranged such that the inner surface of the second reflector 5 whose surface is mirror-finished is arranged in a curved substantially semicircular shape or the like, changes the optical path by 180 degrees, and enters the second light guide plate 8 The light enters the surface 8a. Light incident on the second light guide plate 8 repeats total reflection similarly to the first light guide plate 4, and emits light to the emission surface 8b. In addition, the second light guide plate 8 is provided with an ink dot on an emission surface 8c facing the emission surface 8b or formed in an uneven shape or the like. The light is emitted to the whole 8b. Further, the light emitted to the paired incident surface 8d facing the incident surface 8a is reflected by the reflection sheet 9 and is incident on the second light guide plate 8 again. Further, an optical sheet 10 including a diffusion sheet, a protection sheet, a lens sheet, a prism sheet, and the like is arranged so that the light emitted from the emission surface 8b of the second light guide plate 8 transmits and enters the liquid crystal panel 13. The light source device is completed.
[0011]
The liquid crystal panel 13 includes a color filter substrate sandwiching a liquid crystal layer and a TFT array substrate. The color filter substrate includes R (Red), G (Green), and B (Blue) coloring layers and a light shielding layer. The TFT array substrate includes a switching element, a pixel electrode, and the like. In the liquid crystal panel 13 in which a polarizing plate is stuck on the outside of the color filter substrate and the TFT array substrate, the liquid crystal layer is oriented by turning on and off the voltage by the switching element.
[0012]
The liquid crystal panel 13 is provided with a source substrate (not shown) for inputting ON / OFF signals of voltage, and the source substrate is connected to the liquid crystal panel by a flexible bendable TCP (Tape Carrier Package). The source board is fixed to the heat radiating plate 11 with bolts and nuts, and a connector is mounted for inputting an external video signal. The liquid crystal panel 13 is supported and fixed by the rear metal 6 and the mold frame 7, and the planar light source device is arranged on one of the substrates of the liquid crystal panel 13 to form a liquid crystal display device. With such a configuration, the light from the planar light source device that has reached the liquid crystal panel 13 is modulated in accordance with the video signal, and displays each of the RGB colors.
[0013]
FIG. 4 is a perspective view of the LED unit 31. As shown in the figure, a plurality of RGB LEDs 1 are mounted on a substrate 2 in a straight line at a high density. The first light guide plate 4 in FIG. 1 mixes the RGB colors emitted from the LEDs 1 to generate white. An advantage of using the RGB LED 1 is that a method of generating white by mixing RGB colors has a higher luminous efficiency (= luminous flux amount / input power) than a white LED. In addition, a liquid crystal display device with high color reproducibility can be realized by approximating the transmission characteristics of the RGB emission spectrum and the color filters RGB (not shown) of the liquid crystal panel.
[0014]
FIG. 5 is a sectional view taken along line BB of FIG. 14 is an LED chip, 15 is a die, 16 is a lens, and 17 is an electrode. The lens 16 is provided for protecting the LED chip 14 and adjusting the alignment characteristics. The LED chip 14 is arranged on a die 15 for heat conduction, and is mounted with an adhesive having high thermal conductivity to conduct heat generated by the LED chip 14 to the substrate 2. The LED chip 14 and the electrode 17 are electrically connected by the gold wire 17a, and constitute the LED1. The electrode 17 is connected to the substrate 2 by solder or the like.
[0015]
At present, 85% to 95% of the power consumption of the LED chip 14 is generated as heat, and the remaining 5% to 15% is generated as light and transmitted through the lens 16 to emit light. Although a part of the generated heat is transmitted to the lens 16 of the LED, a large amount of heat is transmitted to the substrate 2 via the die 15 and the electrode 17.
[0016]
In addition, when LEDs are mounted at a high density as shown in FIG. 4, the LED junction temperature, which is the temperature of the heat generating portion of the LED chip, increases, so that the luminance of the planar light source device decreases. The LED junction temperature greatly affects the life and stability of the LED.
[0017]
The substrate 2 includes a glass epoxy substrate 18 and an aluminum plate 19. A copper pattern is formed on the glass epoxy substrate 18 in order to supply power to the plurality of LEDs 1 for each RGB. Further, the glass epoxy substrate is made of glass and epoxy resin and has a heat conductivity of 1/1000 as compared with a metal material, so that it cannot be formed thick. For this reason, in general, an aluminum plate 19 is arranged to make the glass epoxy substrate 18 as thin as possible, to give strength to the back surface, and to improve the thermal conductivity. The aluminum plate 19 is desirably made of pure aluminum (A1050, A1100) having a higher thermal conductivity among aluminum materials. The board 2 is provided with a connector (not shown) for inputting an electric signal to the LED 1, a temperature sensor (not shown) for measuring the temperature of the board 2, and the like.
[0018]
As shown in FIG. 2, the LED unit 31 supports the surface of the substrate 2 opposite to the surface on which the LEDs 1 are mounted by the heat radiating plate 11, and is attached to the heat radiating plate 11 using a plurality of screws (not shown). . The radiator plate 11 supports the LED unit 31 and diffuses heat from the LED 1. Further, the heat radiating plate 11 positions and fixes other components used in the planar light source device, and secures the strength of the entire planar light source device.
[0019]
In addition, a contact thermal resistance, which is a resistance when conducting heat, exists at a contact portion between the LED unit 31 and the heat sink 11. It is important to reduce the contact thermal resistance in order to easily transmit heat from the LED unit 31 which is a heat source to the heat sink 11. Reducing the contact thermal resistance lowers the LED junction temperature. In order to reduce the contact thermal resistance, it is necessary to increase the surface area of the contact surface, smooth the surface of the contact surface, and increase the contact pressure. The area of the contact surface between the LED unit 31 and the heat sink 11 is increased, and the contact surface is formed to be smooth. In order to increase the contact pressure, it is preferable to mount the LED unit 31 to the heat sink 11 at a plurality of locations with screws, but a double-sided tape having high thermal conductivity may be used. Pure aluminum (A1050, A1100, etc.) having high thermal conductivity is often used for the heat sink 11.
[0020]
By the way, there are three forms of heat flow (heat transfer), and there are heat radiation, convection heat transfer, as well as heat conduction moving from a high temperature part to a low temperature part. Convection heat transfer is convection generated when there is a temperature difference between the air and the radiator plate 11. Thermal radiation is a phenomenon in which part of the thermal energy generated by the movement of molecules in a high-temperature object is transmitted through the space between electromagnetic waves. For this reason, the amount of heat transfer of the radiator plate 11 is increased by increasing not only the heat conduction but also the heat emissivity. The thermal emissivity can be increased by oxidizing the surface of the heat radiating plate 11 or applying an organic substance.
[0021]
Further, in the first embodiment, the fan 12 is attached to the heat radiating plate 11 for heat radiation of the LED unit 31. The convection is forcibly generated from the blower 12 to radiate heat from the radiator plate 11. As shown in FIGS. 1 and 2, the blower 12 is attached, for example, near the LED unit 31 and near the side surface 11 c of the heat sink 11. For this reason, the air blown from the blower 12 passes through the gap between the LEDs 1, flows along the support surface 11 a of the radiator plate 11, and flows between the support surface 11 a of the radiator plate 11 and the 4 c surface of the first light guide plate 4. Further, at least one hole 21 is provided on the back surface 11b opposite to the support surface of the heat radiating plate 11 to discharge this air. The hole 21 is provided substantially perpendicular to the heat conduction direction 32 of the heat sink 11. The holes 21 not only allow the air blown from the blower 12 to flow along the support surface 11a of the heat sink 11 but also allow at least one air to be directed to the back surface 11b of the support surface 11a of the heat sink 11. The wind direction changing means is provided in each of the holes 21. The hole 21 is located at a position away from the blower 12 so that air flows over the entire support surface 11a of the radiator plate and all air flowing along the support surface 11a can be directed to the back surface 11b. It is provided at the end of the side surface 11 d of the heat sink 11.
[0022]
When the hole 21 is not provided at the end, a protrusion 20a may be provided so as to easily change the wind direction as shown in FIG. Note that the heat conduction direction 32a shown in FIG. 1 is in the vicinity of the blower 12 in the present embodiment and heat dissipation is promoted, and therefore is not considered in the present embodiment.
[0023]
Although the blower 12 is not particularly limited in the present invention, the number and size of the blower 12, the number of rotations of the propeller, the flow rate, and the wind pressure are arbitrarily set by considering the heat generation amount and the heat release amount of the LED 1. obtain. It is also possible to adjust the rotation ON / OFF or the number of rotations based on the information of the temperature sensor mounted on the substrate 2 to adjust the amount of heat radiation.
[0024]
Further, since the LEDs 1 are arranged at a high density, the gap between the LEDs 1 is narrowed, and the LEDs 1 themselves become the resistance of the air blown from the blower 12, so that eddies are generated around the LEDs 1. Thus, the LED 1 becomes a turbulence promote (turbulence promoter), and the amount of heat radiation around the LED 1 increases. In the present embodiment, the gap between the LEDs 1 becomes the resistance of the air blown from the blower, and the amount of air blown from the blower 12 is reduced. Becomes larger.
[0025]
As shown in FIGS. 1 and 2, the wind direction changing means provided in the hole 21 is, for example, a duct 20 or the like formed integrally with the heat sink 11. After the air blown by the blower 12 is blown to the support surface 11a of the radiator plate 11, the air is formed by the duct 20 toward the back surface 11b of the support surface of the radiator plate 11. The duct 20 protrudes from the back surface 11b of the support surface of the radiator plate 11 so as to cover the hole 21. The duct 20 changes the air (wind direction) by 180 degrees so as to be directed toward the back surface 11b of the support surface of the radiator plate 11. To have a shape having In the first embodiment, three blowers are formed, and two holes 21 and the wind direction changing means 20 are formed.
[0026]
With the configuration of the first embodiment, the air blown by the blower 12 can radiate heat on both sides of the support surface 11a of the heat sink 11 and the back surface 11b of the support surface. Thereby, the heat conduction from the LED 1 to the air is enhanced by using the strong air blowing by the blower 12, and the air is changed from the support surface 11a of the heat sink 11 to the back surface 11b by the wind direction changing means, and the air flowing direction is changed. By setting, the convection of air (mixing of air) can be forcibly accelerated. Since the heat radiating plate 11 can radiate heat, the LED junction temperature can be lowered, and the brightness and reliability of the liquid crystal display surface can be improved. Further, as shown in FIGS. 1 to 3, the duct 20 as the wind direction changing means can be realized by integral molding with the heat radiating plate 11, so that a separate and inexpensive and highly reliable heat radiating mechanism can be realized without requiring a separate member.
[0027]
In addition, since the planar light source device has the above structure, the air discharged from the holes 21 is exhausted to the outside of the planar light source device along the back surface 11b of the support surface of the heat sink 11, so that the directly discharged air Can be arbitrarily set at a position that does not cause discomfort to the user. An exhaust port can be provided at a position where the user does not feel uncomfortable with a notebook PC, a monitor, or the like equipped with the planar light source device.
[0028]
Embodiment 2
In the first embodiment, the duct 20 is arranged perpendicular to the heat conduction direction 32. However, in the second embodiment, the duct 20 is provided substantially parallel to the heat conduction direction 32 as shown in FIG. By providing the duct 20 substantially parallel to the heat conduction direction 32, the heat from the blower 12 can be radiated by directing the air from the blower 12 to the back surface 11 b of the radiator plate 11 near the LED unit 31 having a high heat generation temperature. Therefore, heat can be efficiently radiated from the back surface 11b of the heat radiating plate 11 as compared with the first embodiment. Other configurations are the same as those of the first embodiment. As described above, the number, position, and shape of the ducts 20 can be arbitrarily set based on the heat distribution of the heat sink 11.
[0029]
With the configuration described in the second embodiment, similarly to the first embodiment, the air blown by the blower 12 can radiate heat on both sides of the support surface 11a of the radiator plate 11 and the back surface 11b of the support surface. . Thereby, the heat conduction from the LED 1 to the air is enhanced by using the strong air blowing by the blower 12, and the air is changed from the support surface 11a of the heat sink 11 to the back surface 11b by the wind direction changing means, and the air flowing direction is changed. By setting, the convection of air (mixing of air) can be forcibly accelerated. Since the heat radiating plate 11 can radiate heat, the LED junction temperature can be lowered, and the brightness and reliability of the liquid crystal display surface can be improved. Further, as shown in FIG. 6, the duct 20 as the wind direction changing means can be realized by integral molding with the heat radiating plate 11, so that a separate and inexpensive and highly reliable heat radiating mechanism can be realized without requiring a separate member. Further, by providing the duct 20 substantially parallel to the heat conduction direction 32, heat can be efficiently radiated from the back surface 11b of the heat radiating plate 11 near the LED 1 having a higher heat generation temperature than in the first embodiment.
[0030]
In addition, since the planar light source device has the above structure, the air discharged from the holes 21 is exhausted to the outside of the planar light source device along the back surface 11b of the support surface of the heat sink 11, so that the directly discharged air Can be arbitrarily set at a position that does not cause discomfort to the user. An exhaust port can be provided at a position where the user does not feel uncomfortable with a notebook PC, a monitor, or the like equipped with the planar light source device.
[0031]
Embodiment 3
In the first and second embodiments, the duct 20 as the wind direction changing means is formed integrally with the heat radiating plate 11, but in the third embodiment, the wind direction changing means is formed in the hole 21 by another member 22. As shown in FIG. 7, the separate member 22 is in the vicinity of the hole 21 and is fixed with a screw or the like (not shown) with a fixed gap provided by a pin 23a or the like on the back surface 11b side of the support surface of the radiator plate 11. I do. Further, as shown in FIGS. 8A and 8B, the separate member 22 may be fixed to the apertures 23b and 23c formed by the aperture processing on the radiator plate 11 with screws or the like (not shown) without using pins. it can.
[0032]
By providing another member 22 as a wind direction changing means in the vicinity of the hole 21, the air blown from the blower 12 is blown to the support surface 11 a of the radiator plate 11, and then the air is directed along the back surface 11 b of the radiator plate 11. Close. The separate member 22 is fixed to the back surface 11b side of the heat radiating plate 11 and formed so as to change the wind direction.
[0033]
Further, another member 22 which is a wind direction changing means may be formed on a circuit board. For example, an LED driver, a source substrate other than the LED driver, a gate substrate, a control substrate, a power supply substrate, and the like are mounted on the circuit substrate.
[0034]
The LED 1 is driven by an LED driver. A constant current is supplied to the LED 1 for each of RGB, the duty ratio is controlled for each of the RGB colors, and the light amount of each color can be arbitrarily adjusted. By monitoring the tristimulus value of the second light guide plate 8 with a sensor (not shown), a duty ratio for each of RGB can be adjusted to provide a function of keeping the white point of the display surface constant. Generally, a high heat generating member such as a coil is mounted on the LED driver, and by radiating heat of these components, the reliability and efficiency of the LED driver are improved, so that power consumption can be suppressed. When an LED driver on which a heat-generating member such as a coil is mounted is mounted on a surface 22a (see FIG. 7) facing the back surface 11b of the heat sink 11, the turbulence is promoted (turbulence promoter), and the heat dissipation efficiency of the LED driver is further reduced. Go up. Also, the efficiency of the LED driver increases.
[0035]
With the configuration described in the third embodiment, the air blown by the blower 12 can radiate heat on both sides of the support surface 11a of the radiator plate 11 and the back surface 11b of the support surface. Thereby, the heat conduction from the LED 1 to the air is enhanced by using the strong air blowing by the blower 12, and the air is changed from the support surface 11a of the heat sink 11 to the back surface 11b by the wind direction changing means 22, and the air flows in the direction. Is set, the convection of air (mixing of air) can be forcibly accelerated. Since the heat radiating plate 11 can radiate heat, the LED junction temperature can be lowered, and the brightness and reliability of the liquid crystal display surface can be improved. Further, as shown in FIGS. 7 and 8, since the wind direction changing means is constituted by the separate member 22, heat can be released from the separate member, and the brightness and reliability of the liquid crystal display surface are further improved.
[0036]
In addition, since the planar light source device has the above structure, the air discharged from the holes 21 is exhausted to the outside of the planar light source device along the back surface 11b of the support surface of the heat sink 11, so that the directly discharged air Can be arbitrarily set at a position that does not cause discomfort to the user. An exhaust port can be provided at a position where the user does not feel uncomfortable with a notebook PC, a monitor, or the like equipped with the planar light source device.
[0037]
Embodiment 4
In the fourth embodiment, as shown in FIG. 9, the duct 20 as the wind direction changing means described in the first and second embodiments and the separate member 22 described in the third embodiment are used together. Another member 22 is fixed adjacent to the opening 20 b of the duct 20 provided on the heat sink 11. The fixing method is the same as in the third embodiment.
[0038]
The duct 20 provided in the hole 21 blows the air blown by the blower 12 to the support surface 11a of the radiator plate 11 and then to the back surface. The air whose flow direction has been changed can be set in a separate member 22 fixed in the vicinity of the opening 20b of the duct 20, so that the flow path of the air can be set, so that useless air flow does not occur. Can be effectively released from the back surface 11b of the heat radiating plate 11 near the separate member 22 and the LED unit 31.
[0039]
With the configuration described in the fourth embodiment, the air blown by the blower 12 can radiate heat on both sides of the support surface 11a of the radiator plate 11 and the back surface 11b of the support surface. Thereby, the heat conduction from the LED 1 to the air is enhanced by using the strong air blowing by the blower 12, and the air is changed from the support surface 11a of the heat sink 11 to the back surface 11b by the wind direction changing means, and the air flowing direction is changed. By setting, the convection of air (mixing of air) can be forcibly accelerated. Since the heat radiating plate 11 can radiate heat, the LED junction temperature can be lowered, and the brightness and reliability of the liquid crystal display surface can be improved. Further, as shown in FIG. 9, since both the duct 20 and the separate member are used in combination, it is possible to dissipate heat from the separate member, secure a flow path (direction) of air, and increase the wind speed. The amount of heat radiation of the heat radiating plate 11 can be further increased.
[0040]
In addition, since the planar light source device has the above structure, the air discharged from the holes 21 is exhausted to the outside of the planar light source device along the back surface 11b of the support surface of the heat sink 11, so that the directly discharged air Can be arbitrarily set at a position that does not cause discomfort to the user. An exhaust port can be provided at a position where the user does not feel uncomfortable with a notebook PC, a monitor, or the like equipped with the planar light source device.
[0041]
In addition, the blower 12 described in the first to fourth embodiments is attached to the back surface 11b side of the heat sink 11 as shown in FIGS. 1 to 9, but the same effect can be obtained by a configuration attached to the support surface 11a side. You can play.
[0042]
Embodiment 5
In the first to fourth embodiments, the blower is formed on the heat radiating plate 11. However, in the display device of the fifth embodiment, the frame 29 is formed so as to surround the planar light source device and the liquid crystal panel 13 as shown in FIG. Install the blower 12. The frame body 29 includes a metal frame 24 which is a metal sheet metal frame for fixing the display device at a desired position, an upper case 26, and a lower case 25. The metal frame 24 fixes the heat radiating plate 11 and forms a hole 24a for further discharging the air discharged from the hole 21 to the outside. The upper case 26 and the lower case 25 surround the liquid crystal panel 13 and protect the outside of the display device. The lower case 25 and the upper case 26 are both design parts that require aesthetics, and are made of resin or metal formed by die casting. A hole 25a is formed in the lower case 25 in order to discharge the air discharged from the hole 24a to the outside of the liquid crystal display device. The blower 12 is attached to the sheet metal frame 24 or the lower case 25.
[0043]
Further, the wind direction changing means installed near the hole 21 may be the same as in the first to fourth embodiments.
[0044]
With the configuration described in the fifth embodiment, the air blown by the blower 12 can radiate heat on both sides of the support surface 11a of the radiator plate 11 and the back surface 11b of the support surface. Thereby, the heat conduction from the LED 1 to the air is enhanced by using the strong air blowing by the blower 12, and the air is changed along the back surface 11b from the support surface 11a of the radiator plate 11 by the wind direction changing means, and the air flowing direction is changed. By setting, the convection of air (mixing of air) can be forcibly accelerated. Since the heat radiating plate 11 can radiate heat, the LED junction temperature can be lowered, and the brightness and reliability of the liquid crystal display surface can be improved.
[0045]
Further, as shown in FIG. 10, the blower 12 is attached to the frame 29, so that the outside air can be taken into the display device, and the temperature of the air blown by the blower 12 is kept substantially constant even when used for a long time. be able to. In addition, the heat generating elements installed in the frame body 29 can also radiate heat at the same time, and the frame body 29 and the blower 12 of the planar light source device can be shared, so that the number of the blowers 12 can be reduced.
[0046]
【The invention's effect】
As described above, the surface light source device of the present invention includes a point light source mounted on a substrate and at least one hole formed on the surface opposite to the surface on which the point light source is mounted on the substrate. And a radiator plate provided with a blower for blowing air to the supporting surface for supporting, wherein the air blown to the supporting surface in the hole is directed to the back surface of the supporting surface of the radiating plate. Since the air blower is provided with the wind direction changing means, the air blown by the blower can radiate heat on both the support surface of the heat sink and the back surface of the support surface. With this, the heat conduction from the LED to the air is enhanced by using the strong air blowing by the blower, and the air is changed from the support surface of the heat sink to the rear surface by the wind direction changing means, thereby setting the direction of the air flow. Forcibly, the convection of air (mixing of air) can be accelerated. Since the heat radiating plate can radiate heat, the LED junction temperature can be lowered, and the brightness and reliability of the liquid crystal display surface are improved.
[0047]
Further, the display device of the present invention includes a display panel, a point light source mounted on a substrate disposed on a surface opposite to a display surface of the display panel, and a surface of the substrate on which the point light source is mounted. Is formed so as to surround the display panel and the heat radiator plate, the heat radiator plate supporting the opposite surface and having at least one hole, and the support surface of the heat radiator plate is provided through the at least one hole. A frame provided with a blower that blows air in the display device, wherein the at least one hole directs the air blown to the support surface of the heat sink to the back surface of the support surface. Since it is characterized by comprising means, the heat conduction from the LED to the air is enhanced by using the strong blowing by the blower, and the air is changed from the support surface of the heat sink to the back surface by the wind direction changing means, Setting the direction of air flow Can be forcibly advancing the convection air (mixed air). Since the heat radiating plate can radiate heat, the LED junction temperature can be lowered, and the brightness and reliability of the liquid crystal display surface are improved.
[0048]
Further, the outside air can be taken into the display device, and the temperature of the air blown by the blower can be kept substantially constant even when used for a long time.
[0049]
In addition, the heating element installed on the frame can also radiate heat at the same time, and the frame and the blower of the planar light source device can be shared, so that the number of blowers can be reduced.
[Brief description of the drawings]
FIG. 1 is a perspective view of a planar light source device according to an embodiment of the present invention.
FIG. 2 is a sectional view taken along line AA of FIG.
FIG. 3 is a cross-sectional view illustrating another embodiment of the present invention, in which a projection 20a is further provided on the planar light source device of FIG. 2;
FIG. 4 is a perspective view of an LED unit mounted on the planar light source device according to one embodiment of the present invention.
FIG. 5 is a sectional view taken along line BB of FIG. 4;
FIG. 6 is a perspective view of a surface light source device according to another embodiment of the present invention.
FIG. 7 is a cross-sectional view of a planar light source device according to still another embodiment of the present invention.
8 (a) and 8 (b) show still another embodiment of the present invention, respectively, and a cross section in the case of using a stop formed by drawing a heat sink in place of the pin of FIG. 7; FIG.
FIG. 9 is a sectional view of a planar light source device according to another embodiment of the present invention.
FIG. 10 is a cross-sectional view of a display device according to still another embodiment of the present invention.
[Explanation of symbols]
1 LED
2 substrate
3 First reflector
4 First light guide plate
5 Second reflector
6 rear metal
7 Mold frame
8 Second light guide plate
9 Reflective sheet
10 Optical sheets
11 Heat sink
12 blower
13 LCD panel
14 LED chip
15 die
16 lenses
17 electrodes
17a Gold wire
18 Glass epoxy board
19 Aluminum plate
20 duct
20b opening
21 holes
22 Wind direction changing means
23a pin
23b aperture
24 Metal frame
24a hole
25 Lower case
26 Upper case
29 frame
31 LED unit
32 Heat conduction direction
32a Heat conduction direction

Claims (12)

A point light source mounted on a substrate,
A surface light source device comprising: a radiator plate having at least one hole formed therein and having a blower for blowing air to a support surface for supporting a surface of the substrate opposite to the surface on which the point light source is mounted. hand,
A planar light source device comprising: a wind direction changing unit that directs air blown to the support surface in the hole toward a back surface of the support surface of the heat sink. The planar light source device according to claim 1, wherein the wind direction changing means is formed integrally with the heat sink. The planar light source device according to claim 1, wherein the wind direction changing means is formed as a separate member near a hole of the heat sink. The planar light source device according to claim 1, wherein the wind direction changing means is formed on a circuit board near a hole of the heat sink. 5. The planar light source device according to claim 1, wherein the point light source is an LED. The planar light source device according to claim 1, wherein the point light source is an LED, and the wind direction changing means is formed on a circuit board on which an LED driver is mounted near the hole of the heat sink. A display panel;
A point light source mounted on a substrate disposed on a surface opposite to the display surface of the display panel,
A heat sink that supports a surface of the substrate opposite to the surface on which the point light source is mounted, and has at least one hole;
A display device comprising: a frame formed so as to surround the display panel and the heat sink, and having a blower that blows air through the at least one hole on a support surface of the heat sink. ,
The display device, wherein the at least one hole includes wind direction changing means for directing air blown to the support surface of the heat sink toward the back surface of the support surface. The display device according to claim 7, wherein the wind direction changing unit is formed integrally with the heat sink. 9. The display device according to claim 8, wherein the wind direction changing means is formed as a separate member near a hole of the heat sink. 10. The display device according to claim 9, wherein the wind direction changing means is formed on a circuit board near a hole of the heat sink. The display device according to claim 7, wherein the point light source is an LED. The planar light source device according to claim 7, wherein the point light source is an LED, and the wind direction changing means is formed on a circuit board on which an LED driver is mounted near the hole of the heat sink.

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