JP2007250276A - Lighting system and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To lessen temperature distribution by uniformly cooling a light source (heating element) distributed over the wide area of the light emitting surface of a lighting system. <P>SOLUTION: This lighting system is equipped with a substrate mounting plate 8 holding a light source substrate 10 to which a light source 21 is mounted on one side, and forming a nozzle 22 on the one side correspondingly to the position of the light source 21 mounted to the light source substrate 10; and a fan 14 provided in a back casing 9 to take in the outside air to the side opposite to the one side of the substrate mounting plate 8. The system is structured so that the outside air taken into the other side of the substrate mounting plate 8 is directly injected to the back of the light source substrate 10 by the nozzle 22. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an illuminating device and a liquid crystal display device, and more particularly to an illuminating device suitable for being applied to a backlight device of a liquid crystal display device, and a liquid crystal display device equipped with the illuminating device.

  In recent years, as a display device for a television receiver, in place of a CRT (Cathode Ray Tube), a very thin display such as a liquid crystal display (LCD) or a plasma display (PDP) is provided. Display devices have been proposed and put into practical use. In particular, liquid crystal display devices that use liquid crystal display panels can be driven with low power consumption, and the spread of the large liquid crystal display panels has been reduced, leading to technical research and development. ing.

In such a liquid crystal display device, a backlight system in which a color image is displayed by illuminating a transmissive liquid crystal display panel including a color filter with a backlight device that illuminates the surface from the back side becomes the mainstream. ing.
As the light source of the backlight device, a cold cathode fluorescent lamp (CCFL) that emits white light using a fluorescent tube and a light emitting diode (LED) are promising.
In particular, with the development of blue light-emitting diodes, light-emitting diodes that emit red, green, and blue light, which are the three primary colors of light, are now available. Red light, green light, and blue light emitted from these light-emitting diodes By mixing light, white light with high color purity can be obtained. Therefore, by using this light emitting diode as the light source of the backlight device, the color purity through the liquid crystal display panel is increased, so that the color reproduction range can be greatly expanded compared with the CCFL. Furthermore, the brightness of the backlight device can be significantly improved by using a high-power light emitting diode (LED) chip.

  Usually, in a backlight device that uses light emitting diodes of a plurality of colors as light sources, each light emitting diode of red light, green light, and blue light varies in luminance depending on the temperature. Therefore, in order to improve the luminous efficiency (brightness) and make the luminance distribution uniform for each color, how to cool the heat inside the backlight device and reduce the temperature distribution of the light emitting diode light source in the entire screen as much as possible. That is, a cooling structure capable of soaking is required.

  Conventionally, in order to release the heat generated inside the backlight device to the outside, a steel plate with good heat dissipation or aluminum is used for the rear case, and a heat sink such as a heat radiating fin is installed on the outer surface of the rear case. . Or, a cooling fan was provided to perform forced air cooling.

  For example, in a backlight device using a light-emitting diode as a light source, a backlight device in which a cooling fan, a heat bypass, and a heat sink are provided as cooling means has been proposed (see, for example, Non-Patent Document 1).

Nikkei Electronics (Nikkei BP), December 20, 2004 (No. 889), pages 123-130

However, when the number of light emitting diodes in the backlight device increases due to an increase in the screen size of the liquid crystal display device, it is necessary to increase the number of heat pipes accordingly, leading to high cost, deterioration in productivity, and weight increase.
Alternatively, a method of attaching a large number of cooling fans or arranging a heat sink over the entire screen of the backlight device is conceivable. However, this also has a problem that it leads to high cost, deterioration of manufacturability, and weight increase.

  The present invention has been made in view of such a point, and an object thereof is to uniformly cool a light source (a heating element) distributed over a wide area of a light emitting surface such as a lighting device to reduce a temperature distribution.

  In order to solve the above problems, an illumination device of the present invention holds a light source substrate on which a light source is mounted on one surface, and a nozzle on the one surface corresponding to the position of the light source mounted on the light source substrate. And a fan that is provided in a rear case and takes in outside air to the opposite side of the one surface of the substrate mounting plate, and is taken into the other surface of the substrate mounting plate. It is characterized in that the outside air is directly jetted from the nozzle to the back surface of the light source substrate.

  According to the above configuration, the outside air taken into the lighting device is directly and uniformly ejected from the nozzles to the light source (heating element) distributed over a wide range of the light emitting surface.

  Further, the liquid crystal display device of the present invention is a liquid crystal display device comprising a liquid crystal panel and a backlight device that illuminates the liquid crystal panel from the back side. The backlight device includes a light source substrate on which a light source is mounted. A substrate mounting plate that is held on one surface facing the liquid crystal panel and has a nozzle formed on the one surface corresponding to the position of the light source mounted on the light source substrate, and the one of the substrate mounting plates And a fan for taking in the outside air to the opposite surface, and the outside air taken into the other surface of the substrate mounting plate is directly sprayed from the nozzle to the back surface of the light source substrate. .

  According to the above configuration, the outside air taken into the backlight device is directly and uniformly ejected from the nozzles to the light sources (heating elements) distributed over a wide area throughout the screen.

According to the present invention, since air is directly and uniformly ejected to a light source (heating element) distributed over a wide area over the entire light emitting surface, the temperature distribution over the entire light emitting surface can be made uniform.
Further, when the illumination device is used as a backlight device of a liquid crystal display device, the light emitted to the liquid crystal panel is stabilized by the uniform light emission over the entire area of the backlight device, and uneven brightness and uneven color are suppressed. Therefore, the image quality of the liquid crystal display device is improved.

  Hereinafter, examples of embodiments of the present invention will be described with reference to the accompanying drawings. In this example, the illumination device of the present invention is applied to a backlight device of a transmissive liquid crystal display device.

  FIG. 1 is a schematic exploded perspective view of a liquid crystal display device according to an embodiment of the present invention. As shown in FIG. 1, it is made of resin such as plastic for fixing the light source substrate 10 so as to face the back surface portion 9a of a box-shaped back panel (back housing) 9 made of steel (steel plate) or aluminum. A substrate mounting plate (hereinafter referred to as a substrate bracket) 8 is fixed. Convex portions 13 and 13 for installing two fans 14 and 14 for cooling are formed on the back surface portion 9a of the back panel 9, and air holes 12 and 12 are formed in the centers of the convex portions 13 and 13, respectively. Has been. For example, an axial fan is used for the fans 14 and 14, and outside air (gas) taken from the outside is taken into the backlight device through the ventilation holes 12 and 12.

  Diffusion members (hereinafter referred to as fan diffusers) 11 and 11 are installed between the back panel 9 and the substrate bracket 8, and a light source is utilized using air taken into the backlight device from the fans 14 and 14. Cool efficiently. The shape of the protrusions 13 and 13 corresponds to the fan diffusers 11 and 11 and is formed to protrude toward the side of the back panel 9 where the fans 14 and 14 are installed, that is, the back side of the backlight device. Has been. Details of the cooling mechanism using these fans and fan diffusers will be described later. In addition, although the shape of the convex parts 12 and 12 formed in the back panel 9 is substantially rectangular, it is not restricted to this example.

  A plurality of light source substrates 10 in which light emitting diodes are arranged as light sources are held on the surface of the substrate bracket 8 (the side facing the liquid crystal panel 3), and on the light source substrate 10, the light source substrate 10 of the bottom surface portion 7a is provided. A box-shaped reflection sheet 7 that has a hole formed at a position corresponding to the light source and reflects light emitted from the light source is installed. The bottom surface portion 7a of the reflection sheet 7 is fixed to the substrate bracket 8 with a double-sided tape 7b or the like. Details of the adhesion will be described later.

  Above the reflection sheet 7, there is a diffusion plate 6 for diffusing the light emitted from the light source, and optical sheets (diffusion sheet, prism sheet, etc.) 5, which are covered with a middle frame 4 having a large opening serving as an illumination surface. Thus, a backlight device is configured.

  Then, the liquid crystal panel 3 is placed on the heel of the middle frame 4, and finally the entire liquid crystal panel 3 including the liquid crystal panel 3 is fixed with a metal or resin top frame 2 to complete the liquid crystal display device 1. As described above, the liquid crystal display device 1 is assembled by stacking the component parts in close contact with each other.

  FIG. 2 is a schematic perspective view in a cross section of the backlight device mounted on the liquid crystal display device 1. For convenience of explanation, FIG. 2 is a perspective view showing a part of the light source substrate with a two-dot chain line. As shown in FIG. 2, the board bracket 8 holds a predetermined number of light source boards 10 on which the light emitting diodes 21 are mounted in a predetermined position. In order to improve heat conduction, it is preferable to use a material having excellent heat conduction such as aluminum for the base material of the light source substrate 10.

  The substrate bracket 8 has a nozzle 22 integrally formed with the substrate bracket 8 on the surface on which the light source substrate 10 is attached. The nozzle 22 is formed in a convex shape toward the back surface of the light source substrate 10 corresponding to the position of each light emitting diode 21 mounted on each light source substrate 10, and the fan 14 passes through the blower holes 12 and the back surface of the substrate bracket 8. The outside air taken in to the side is ejected from the nozzle 22 toward the back of the light source substrate 10.

  The surface of the substrate bracket 8, that is, the surface on which the nozzles 22 are formed is a column (hereinafter referred to as a stud) 23 that supports the optical sheets 5 and the diffusion plate 6, and the bottom surface portion 7 a of the reflection sheet 7. A reflection sheet bonding portion 24 for bonding is provided.

  Actually, the reflection sheet 7 having the bottom surface portion 7a in which holes are formed at positions corresponding to the respective light emitting diodes 21 is placed on these light source substrates 10, but this is not shown in FIG. is doing. In this example, the light emitting diode 21 is composed of three colors of red light, green light, and blue light, and each color is mixed to generate a white light source.

  A fan diffuser 11 is provided on the opposite side (back side) of the surface of the substrate bracket 8 on which the nozzles 22 are provided. The fan diffuser 11 is latched by latching portions 29, 29 formed on the back surface portion 8 a of the board bracket 8. The shape of the fan diffuser 11 is a shape in which the central portion protrudes, for example, a shape such as a cone or a conical surface thereof, and in this example, a curved surface 11a is formed radially from the central portion to the end portion. The fan diffuser 11 has an effect of spreading fresh outside air taken in by the fan 14 to every corner on the back side of the board bracket 8. The curved surface 11a may have a curved surface or a partially inclined surface as in this example, as long as the curved surface 11a has a slope suitable for spreading outside air around the board bracket 8.

  The convex portion 13 of the back surface portion 9 a of the back panel 9 is formed corresponding to the shape of the fan diffuser 11. That is, a constant distance is set between the fan diffuser 11 and the convex portion 13. By doing in this way, since the passage of the outside air taken in from the fan 14 becomes wide, the outside air hitting the fan diffuser 11 reaches the surroundings without stagnation.

  Now, the principle of the cooling method according to the present invention will be described in detail with reference to FIGS.

  FIG. 3 is a schematic cross-sectional view of a backlight device showing the concept of the present invention. In FIG. 3, outside air, that is, air is taken into the backlight device from the fan 14 in a state where the respective components of the backlight device are stacked and assembled. The air sent from the fan 14 extends along the curved surface 11 a of the fan diffuser 11 inside the back side 8 a of the board bracket 8 and fills the space sealed by the back side 9 a of the back panel 9 and the board bracket 8. The

  FIG. 4 is a schematic rear view of the substrate bracket 8, and shows the back panel 9 seen through. As shown in FIG. 4, it can be understood that the air taken in from the fan 14 spreads to every corner by the fan diffuser 11 inside the back panel 9, that is, the back side 8 a of the board bracket 8. As an example, a driver circuit 31 connected to the light source substrate 10 and the flexible cable 30 is provided around the end portion of the back side 8 a of the substrate bracket 8. Not only this but another circuit board may be installed. The flexible cable 30 is a bundle of a plurality of flexible cables 26, 27,... Connected to each light source substrate 10.

  Then, air filled toward the back side 10a of the light source substrate 10 is ejected from the nozzles 22 formed in the number of the light emitting diodes 21 on the front side of the substrate bracket 8, and cooling of the light emitting diodes 21 against heat generation starts. The injected air is blocked by the light source substrate 10 and the bottom surface portion 7a of the reflection sheet 7, and is exhausted to the outer periphery of the back surface side 8a of the substrate bracket 8 along the back surface 10a.

  The temperature of each part was measured with respect to the backlight device configured as described above. This measurement was performed mainly on the right half of the 60 light source substrates 10 mounted on the backlight device for the 46-inch liquid crystal display device with all the light emitting diodes turned on. The measurement was performed by applying a thermocouple to the central portion (see FIG. 6) of red light, green light, and blue light of the light emitting diode 21 on the surface of each light source substrate 10. The drive current of each light source substrate 10 is uniform.

  As shown in FIG. 5, the measurement positions are [a] the surface of the light source substrate (on the right end of the backlight device), [b] the same left side (middle of the right end), and [c] in the almost right half of the front surface 35 of the backlight device. Same as left (bottom right), [d] Same left (upper right center), [e] Same left (middle of right side, fan back), [f] Same left (bottom right center lower), [g] Same left (right side) Upper left), [h] Same left (right middle left), [i] Same left (right lower left), [j] Same left (left middle right), [k] Fan suction part. The measurement point [e] corresponds to a position almost directly behind the fan. In the fan suction section, the outside air taken into the back surface side of the substrate bracket 8 in the backlight device by the fan is measured, so that a temperature substantially equal to room temperature can be obtained. The measurement results are shown in Table 1.

  As a result of the measurement, the difference between the maximum value and the minimum value of the temperature at each measurement position was 3.8 ° C. This difference in temperature distribution was within a range appropriate for display quality in a liquid crystal display device including a backlight device using light emitting diodes of a plurality of colors as light sources. This is a cooling effect equivalent to the case of using a heat vip.

  According to the cooling structure according to the present invention described above, air is directly and uniformly injected from the nozzle formed on the substrate bracket to the light source (heating element) distributed over a wide range of the entire screen, so that the cooling efficiency is high. It can be cooled so that the temperature distribution is uniform.

  In addition, since no heat sink or heat pipe is used, the cost can be greatly reduced, and the process for assembling can be greatly reduced, thereby improving workability. Furthermore, since it is not necessary to use a metal material, it is advantageous for weight reduction.

  Further, even when the heat generation amount is partially high or the temperature is likely to rise, it is possible to cope with the adjustment of the nozzle diameter and position.

  In addition, since it is not necessary to use a large number of fans, it is advantageous in terms of workability, cost, and noise.

  In the backlight device of this example, there is little variation in the temperature of the light emitting diodes of the respective colors constituting the light source, so that the luminance distribution of each color becomes uniform and the liquid crystal panel 3 can be irradiated with uniform white light. Therefore, uneven brightness and uneven color of the liquid crystal display device are suppressed, and display quality is improved.

  The liquid crystal display device 1 of the present example is provided with two cooling fans 14, but one fan may be used as long as a sufficient air volume is ensured. On the other hand, if the air volume is insufficient, it can be handled by adding three or four.

  Further, the diameter of the nozzle 22 does not always have to be constant, and by increasing or decreasing the nozzle diameter depending on the location in the board bracket 8, when the fan position is not at the center, It can also be used when you want to increase the cooling effect locally, such as when the temperature rises differently depending on the location.

  Also, not only the light emitting diode as a light source, but also a heating element distributed over a wide range, for example, a circuit board such as a driver circuit and a correction circuit installed on the outer periphery of a backlight device, the nozzle installation location It is possible to cope with the same structure by adjusting.

  Further, when the fan 14 is slightly offset rather than directly behind the heating element, uniform air injection is possible by adjusting the nozzle diameter, such as increasing the nozzle diameter of the substrate bracket 8.

  Further, although the reflection sheet 7 is usually required as the backlight device, a certain cooling effect can be obtained by the cooling mechanism of this example even if it is not present. However, it is more preferable to have the reflection sheet 7.

  In the above example, the light emitting diode is used as the light source of the backlight device. However, a light emitting diode other than the light emitting diode such as a cold cathode ray tube may be used. Moreover, the said cooling structure is applicable not only to a backlight apparatus but the cooling of the illuminating device generally.

  By the way, the board bracket 8 of this example was invented to cool the light source board 10, but has a plurality of functions without additional parts in addition to the cooling function, thereby reducing the number of parts and the cost. And the effect of improving workability. Hereinafter, these functions will be described.

  First, a structure in which the light source substrate 10 is nail-fixed by the substrate bracket 8 will be described.

  FIG. 6 is a diagram for explaining the substrate bracket 8 and is a schematic perspective view of a cross section of the backlight device. In FIG. 6, for convenience of explanation, the light source substrate 10 is represented by a two-dot chain line. The board bracket 8 is formed with a guide member 41, a locking part 42, a guide member 43, and a claw part 44 as means for fixing the light source board 10. The locking portion 42 protrudes from the upper portion of the guide member 41 and is provided in a bowl shape, and the claw portion 44 is provided to protrude from the upper portion of the guide member 43. As shown in FIG. 7 after the optical substrate 10 is fixed, the guide members 41 and 43 position the light source substrate 10 in the height direction. In addition, the locking portion 42 performs positioning in the horizontal direction of the light source substrate 10, that is, in a plane parallel to the main surface of the substrate bracket 8, and suppresses upward movement of the light source substrate 10. At this time, the gap between the upper end of the guide member 41 and the flange portion of the hooking portion 42 is provided with a gap of one or more light source substrates 10.

  When attaching the light source substrate 10, first, the light source substrate 10 is placed on both guide members 41 and 43. Then, the notch portion 10b of the light source substrate 10 is engaged with the engaging portion 42, thereby roughly positioning the light source substrate 10. Finally, by pushing the light source substrate 10 downward while pushing the light source substrate 10 toward the notch portion 10 b, the edge of the light source substrate 10 opposite to the notch portion 10 b is hooked on the claw portion 44 and the light source substrate 10 is fixed to the substrate bracket 8. Is done.

  Conventionally, by using a screw (male screw) to fix the light source substrate 10 to an arbitrary board mounting plate, by realizing the screwless (screw removal) by the method of this example, The number of parts can be reduced and the weight can be reduced. In addition, the workability can be improved by simplifying the mounting work. Therefore, as a result of these, a significant cost reduction of the product can be expected. In particular, the larger the number of light source substrates 10, the greater the effect.

  Second, the structure in which the substrate bracket 8 also serves as a stud will be described.

  Normally, studs are required as dedicated parts for supporting the diffusion plate and the like, and a larger number of studs are required as the screen becomes larger. However, managing the studs as individual dedicated parts is cumbersome and requires a step of installing the studs on the board mounting board.

  In this example, as shown in FIG. 6, the stud 23 is formed integrally with the board bracket 8 by injection molding, and the number of parts can be reduced by using the board bracket 8 as a stud. In addition, an effect of improving workability can be obtained. As a result, a significant cost reduction of the product can be expected. Furthermore, by integrally forming the stud 23 on the board bracket 8 by injection molding, it is possible to easily cope with an increase in the number of studs.

  Thirdly, a structure in which the substrate bracket 8 also serves as an adhesive surface of the reflection sheet 7 will be described.

  In this example, the reflective sheet adhesive portion 24 is formed integrally with the substrate bracket 8 on the surface of the substrate bracket 8, that is, the surface on which the nozzle 22 is formed. The sheet 7 is composed of a plurality of cylinders for supporting and adhering to the bottom surface portion 7b. In addition, the shape of the reflection sheet adhesion part 24 is not restricted to a cylinder.

  If it is a prior art, the separate component for reflecting sheet fixation will be needed, or it will adhere | attach on another component. However, since the reflective sheet bonding portion 24 of this example has a high degree of freedom in shape and surface area, it is easy to adjust the adhesive force. The reflective sheet 7 may be peeled off when the liquid crystal display device 1 is repaired, and the adhesive surface with the reflective sheet 7 is required to have an adhesive surface shape that is easy to peel off. It is easy to peel off by adhering with, and it becomes easy to reuse. Furthermore, since there are no additional parts, it contributes to parts reduction. As a result, a significant cost reduction of the product can be expected.

  Fourth, the cable processing function of the board bracket 8 will be described.

  As shown in FIG. 2, a flexible cable 26 is connected to a connector 25 mounted at a predetermined position of each light source board 10 fixed to the board bracket 8, and the flexible cable 26 is connected to the flexible cable 27 of the adjacent light source board. Are bundled one after the other, and are bundled one after another so that the lower side of the light source substrate 10 is turned and fixed together by a clamp-shaped fixing member 23 for fixing the flexible cable. The fixing member 28 is formed integrally with the board bracket 8.

  Conventionally, a large number of separate clampers were required, but by using the configuration as in this example, the flexible cable and the air flow were disturbed using the space without the cooling air injection nozzle. Since it can be easily fixed by the fixing member 28 integral with the nail substrate bracket 8, the effects of improving workability and reducing the weight can be obtained. Since no additional parts are required, the number of parts can be reduced. As a result, the cost of the product can be greatly reduced. Further, when the number of cables is increased or the number of processing points is increased, the number of the fixing members 28 can be easily increased or decreased when the board bracket 8 is formed.

  In the case of a backlight device for a large screen, since the number of flexible connectors increases, it is difficult to route it to only one of the backlight devices. In that case, as shown in FIG. 6, when the cable 55 connected to the light source substrate 10 is folded back and routed toward the other end of the backlight device (the direction opposite to the cable of FIG. 2), A plurality of cables from the light source substrate 10 can be bundled without difficulty. The cable 55 in this case may be a straight cable.

  Here, another fixing method of the light source substrate will be described. As shown in FIG. 8, in preparation for the case where the light source substrate 10 needs to be fastened with screws (male screws), a cylindrical portion 55 that uses the substrate bracket 8 as a boss at the time of manufacture is formed. Then, when it is necessary to fix with the screws 56, the screws 56 are applied to the cylindrical portion 55 provided on the substrate bracket 8 to fix the light source substrate 10 to the substrate bracket 8. In addition, in the example of FIG. 8, although the guide member 43 and the nail | claw part 44 are used supplementarily, these are not necessarily required.

  Next, the improvement regarding a photo sensor and a temperature sensor is demonstrated.

  In a backlight device for a liquid crystal display device using a light emitting diode as a light source, a photo sensor (optical sensor) for measuring the mixture of red light, green light and blue light, and a temperature for measuring the light emitting diode A temperature sensor is required. In the conventional model, each sensor is mounted on a different board, and is installed at a position different from or away from the measurement target. Therefore, it is costly and requires many work steps.

  In addition, since it was difficult to measure the temperature of the light source board directly with conventional temperature sensors, the temperature of sheet metal parts, etc. that fixed the board was measured. Since the transmission is also taken into account, the measurement accuracy is inferior.

  An example of installation of a conventional temperature sensor is shown in FIG. The example of FIG. 9 is a cooling technique described in Patent Document 1. In FIG. 9, the LED unit 61 is mounted on the light source substrate (or wiring substrate) 64, and the heat pipe 67 is used to radiate heat generated by the LED chip 63 built in the LED package 62 of the LED unit 61. Is going. However, this structure requires a holding member 66 for holding the heat pipe 67. In addition, a plurality of components are used such that heat generated in the LED chip 63 is conducted to the heat pipe 67 through the holding member 66 and further measured by the temperature sensor 68 installed at a predetermined position through the back panel 65. Because the heat that was transmitted through was measured, there remains a problem with accuracy. In the experiment, it was also obtained that there is a difference of about 5.7 ° between the latest temperature of the LED chip 63 and the temperature measured by the temperature sensor 68.

  Therefore, in this example, the structure is such that the temperature sensor and the photo sensor are mounted on a single substrate. As shown in FIG. 6, the sensor substrate 45 on which the temperature sensor 49 and the photosensor 50 are mounted is placed on the height and positioning guide members 46 and 47 provided on the substrate bracket 8, and the light source substrate 10 and the substrate bracket are mounted. 8 is fixed by the claw portion 48 so as to be sandwiched between the two. At this time, the temperature sensor 49 and the photosensor 50 are attached toward the light source substrate 10, and the sensor substrate 45 is installed in a place where the air jet nozzle 22 does not exist.

  A connector 51 is provided on the back surface of the sensor substrate 45 and is detachably connected to a connector 52 provided at one end of the flexible cable 53. The flexible cable 53 can be routed to the outside through a hole 54 provided in the back surface portion 9 a of the back panel 9.

  Thus, fixing the sensor substrate 22 at the portion without the nozzle 22 has little effect on the cooling effect, and the fixing method using no screws can reduce the number of parts and improve the workability.

  Further, the temperature sensor 49 is configured to be in contact with the back surface of the light source substrate 10 through a heat transfer sheet (not shown), thereby directly measuring the temperature of the back surface of the light source substrate 10 through the heat transfer sheet. Can do. Unlike conventional methods, measurement is performed without interposing other components, so that there is little influence of the thermal conductivity of each component, heat transfer between different components, etc., and the measurement accuracy is greatly improved.

  In addition, as shown in FIG. 6, by measuring the sensor central portion of the photosensor 50 in the gap between the adjacent light source substrates 10, the light mixing degree is measured from a hole (not shown) formed in the reflection sheet 7. Is possible.

  Further, the hole 54 in the back surface portion 9a of the back panel 9 can be connected from the back side of the back panel 9 to the connector 51 of the sensor substrate 45 installed on the substrate bracket 8, so that the wire rod is placed inside the back panel device. There is no need to pass through, the length of the wire can be shortened, and the connector 51 of the sensor substrate 45 and the connector 52 of the flexible cable 53 are detachable, so that workability is good.

  Further, since the sensor substrate 45 can be fixed without using screws, there are effects such as reduction in the number of parts, cost reduction, and reduction in work time.

  Further, since the sensor substrate 45 is fixed to the substrate bracket 8 made of resin such as plastic, the fixing position can be freely changed by adjusting the positions and shapes of the guide members 46 and 47.

  Further, in a large-screen liquid crystal display device or the like, even if the temperature sensor 49 or the photosensor 50 is required in a plurality of locations of the back panel device instead of one, only the sensor substrate 51 is added inside the back panel device. And can be handled relatively easily.

  The present invention is not limited to the above-described embodiments, and various modifications and changes can be made without departing from the scope of the present invention.

1 is a schematic exploded perspective view of a liquid crystal display device according to an embodiment of the present invention. 1 is a schematic perspective view of a backlight device according to an embodiment of the present invention. It is a cross-sectional schematic diagram for demonstrating the concept of the cooling method by this invention. It is a back surface schematic diagram of the board bracket concerning one embodiment of the present invention. It is a figure where it uses for description of the temperature measurement point of the backlight apparatus which concerns on one Embodiment of this invention. It is a figure where it uses for description of the board | substrate bracket which concerns on one Embodiment of this invention. It is explanatory drawing which shows the fixing method of the light source board | substrate which concerns on one Embodiment of this invention. It is explanatory drawing which shows the modification of the fixing method of the light source board | substrate which concerns on one Embodiment of this invention. It is a schematic diagram which shows the example of installation of the conventional temperature sensor.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display device, 2 ... Front frame, 3 ... Liquid crystal panel, 4 ... Middle frame, 5 ... Optical sheet, 6 ... Diffusing plate, 7 ... Reflective sheet, 7a ... Bottom part, 8 ... Substrate bracket, 9 ... Back Panel (rear housing), 9a ... back portion, 10 ... light source substrate, 10b ... notch, 11 ... diffusion member (fan diffuser), 11a ... curved surface, 12 ... air blow hole, 13 ... convex portion, 14 ... fan , 21 ... Light emitting diode, 22 ... Nozzle, latching part 29

Claims (7)

A substrate mounting plate in which a light source substrate on which a light source is mounted is held on one surface, and a nozzle is formed on the one surface corresponding to the position of the light source mounted on the light source substrate,
A fan that is provided in a rear housing and takes outside air into the opposite surface to the one surface of the substrate mounting plate;
The illuminating device characterized in that outside air taken into the other surface of the substrate mounting plate is sprayed from the nozzle to the back surface of the light source substrate. The illuminating device according to claim 1, wherein the diameter of the nozzle is changed in accordance with a desired cooling performance. The lighting device according to claim 2, wherein only a part of the nozzle diameter is changed. The illuminating device according to claim 1, further comprising: a diffusing member that diffuses outside air taken in by the fan radially to the other surface of the substrate mounting plate between the substrate mounting plate and the fan. The lighting device according to claim 1, wherein the lighting device is formed so as to ensure a certain distance between the diffusion member and the rear housing. The illumination device according to claim 1, wherein a nozzle is formed at a position corresponding to a heating element other than the light source of the substrate mounting plate. In a liquid crystal display device comprising a liquid crystal panel and a backlight device that illuminates the liquid crystal panel from the back side,
The backlight device includes:
A substrate mounting plate in which a light source substrate on which a light source is mounted is held on one surface facing the liquid crystal panel, and a nozzle is formed on the one surface corresponding to the position of the light source mounted on the light source substrate When,
A fan for taking outside air into the opposite surface to the one surface of the substrate mounting plate,
The liquid crystal display device, wherein the outside air taken into the other surface of the substrate mounting plate is sprayed from the nozzle to the back surface of the light source substrate.

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