HK1141858A - Lighting equipment and display device using the same - Google Patents

Description

Illumination device and display device using the same

Technical Field

The present invention relates to an illumination device used for a backlight or the like and a display device using the same.

Background

In recent years, for example, liquid crystal display devices have been widely used in liquid crystal televisions, monitors, cellular phones, and the like as flat panel displays having advantages such as thinness and light weight as compared with conventional cathode ray tubes. Such a liquid crystal display device includes an illumination device that emits light and a liquid crystal panel that displays a desired image by functioning as a shutter for light from a light source provided in the illumination device.

Further, in the above-described lighting device, the linear light source including the cold cathode tube or the hot cathode tube is disposed in an edge light type or a direct type on a side or a lower side of the liquid crystal panel. However, the cold cathode tubes and the like described above contain mercury, and it is difficult to recover the cold cathode tubes and the like that are discarded. Therefore, a Light Emitting Diode (LED) using no mercury is proposed as an illumination device for a light source (see, for example, japanese unexamined patent application publication No. 2006-128125).

In addition, in the conventional lighting device described in patent document 1, there is disclosed a technique in which a plurality of driving elements for driving the light emitting diodes are provided on a mounting surface of a printed circuit board on which the plurality of light emitting diodes are mounted. In the conventional lighting device, the plurality of light emitting diodes and the plurality of driving elements are provided on one printed circuit board, so that the productivity of the lighting device can be improved.

However, in the above-described lighting device, in order to cope with a larger screen size, higher luminance, and the like of the liquid crystal display device, it is required to increase the number of light emitting diodes to be provided. In particular, in high-end products such as liquid crystal televisions capable of receiving digital broadcasting, an increase in the number of leds is strongly required because it is an essential condition that the luminance is improved by an increase in the number of leds.

However, in the above-described conventional lighting device, since a plurality of light emitting diodes (light emitting elements) and a plurality of driving elements (driving circuit elements) are mounted on a mounting surface of one printed circuit (light source substrate), heat generated by the light emitting diodes and the driving elements affects each other, and the ambient temperature of the light emitting diodes greatly increases due to heat from the driving elements. As a result, in the conventional lighting device, the light emission efficiency of each light emitting diode is lowered, and a desired amount of light emission may not be obtained. In particular, when the number of light emitting diodes to be mounted is increased, the amount of light emitted from each light emitting diode is significantly reduced, and it is sometimes difficult to improve the light emission quality, and it is sometimes difficult to cope with the high-end products.

Disclosure of Invention

The present invention has been made in view of the above problems, and an object of the present invention is to provide an illumination device capable of improving light emission quality even when the number of light emitting elements to be provided is increased, and a display device using the illumination device.

In order to achieve the above object, an illumination device according to the present invention includes a light emitting element, and a light source substrate having a mounting surface on which the light emitting element is mounted, the illumination device including: the light source substrate is provided with a plurality of light emitting elements on a mounting surface thereof, and a driving circuit element for driving the light emitting elements is provided on a back surface of the mounting surface.

In the light source substrate in the lighting device configured as described above, a plurality of light emitting elements and driving circuit elements are provided in a dispersed manner on the mounting surface and the rear surface, respectively. Thus, even when the number of light-emitting elements to be provided is increased, unlike the above-described conventional example, it is possible to suppress the influence of heat generated by the light-emitting elements and heat generated by the driver circuit element on each other, and it is possible to prevent the ambient temperature of the plurality of light-emitting elements from increasing due to heat from the driver circuit element. As a result, unlike the above-described conventional example, it is possible to prevent the light-emitting efficiency of each light-emitting element from being lowered, and to improve the light-emitting quality.

In the above lighting device, it is preferable that a plurality of light emitting element rows including a plurality of the light emitting elements arranged in a predetermined direction and at a predetermined interval are provided on the mounting surface of the light source substrate,

a driving circuit element for driving the light emitting elements is provided on the back surface of the mounting surface, and the driving circuit element is disposed between the plurality of light emitting element rows.

In this case, the mutual influence of the heat generated by the light-emitting element and the drive circuit element can be more reliably suppressed, and the light emission quality of the lighting device can be easily improved. In addition, since the plurality of light emitting elements are provided along the predetermined direction at predetermined intervals in the light emitting element row, it is possible to easily prevent the occurrence of luminance unevenness in the light irradiated from the illumination device.

In the lighting device, it is preferable that the lighting device includes a base that houses the light source substrate, a heat dissipation portion that dissipates heat generated by the light emitting element is provided on the back surface of the light source substrate, and the base dissipates heat from the heat dissipation portion to the outside.

In this case, since the heat radiation portion conducts the heat generated by the light emitting element from the mounting surface side to the rear surface side, the heat can be efficiently radiated to the outside.

In the lighting device, a heat transfer member may be provided between the base and the heat dissipation portion.

In this case, heat generated by the light emitting element can be efficiently dissipated to the outside.

In the lighting device, the heat transfer member is preferably provided with elasticity.

In this case, the heat transfer member is in surface contact with the chassis and the heat dissipation portion by the elasticity given thereto, and the heat generated by the light emitting element can be reliably conducted to the chassis side and dissipated to the outside.

In the above lighting device, the heat transfer member is preferably provided with adhesiveness.

In this case, the heat transfer member is in surface contact with the chassis and the heat dissipation portion in a stable state due to the adhesion provided, and the heat generated by the light emitting element can be more reliably conducted to the chassis side and dissipated to the outside.

In the lighting device, the light emitting element may be a light emitting diode.

In this case, the lighting device with low power consumption and excellent environmental performance can be easily configured.

In the lighting device, the light emitting elements may be a plurality of types of light emitting diodes which emit light of different colors and can be mixed into white light.

In this case, the lighting device can be easily configured to improve the color purity of the emission color of each of the plurality of types of light emitting diodes and to have excellent emission quality.

In the above lighting device, it is preferable that the light emitting element includes a plurality of light emitting diode packages which use a plurality of types of light emitting diodes having different emission colors from each other and which are capable of mixing the light into white light, and,

the plurality of sets of light emitting diode packages are provided on the mounting surface along the predetermined direction and at predetermined intervals.

In this case, by emitting light from the light emitting diodes in units of light emitting diode packages, it is possible to configure an area active backlight driving type illumination device that can cope with a high-performance display device.

Further, a display device according to the present invention includes a display unit, and is characterized in that: the display unit is irradiated with light from any one of the lighting devices.

In the display device configured as described above, even when the number of light-emitting elements to be provided is increased, since the lighting device capable of improving the light emission quality is used, a high-performance display device having high luminance and excellent display quality can be easily configured.

According to the present invention, it is possible to provide an illumination device capable of improving light emission quality even when the number of light-emitting elements to be provided is increased, and a display device using the illumination device.

Drawings

Fig. 1 is an exploded perspective view showing a liquid crystal display device using an illumination device according to an embodiment of the present invention.

Fig. 2 is an exploded perspective view of the lighting device.

Fig. 3 is a diagram for explaining a specific example of the illumination region and the display region set in the liquid crystal display device.

Fig. 4 is a plan view showing a main part structure of the lighting device.

Fig. 5 is a diagram illustrating the structure of the LED substrate shown in fig. 4, and (a), (b), and (c) are diagrams showing the mounting surface, the rear surface, and the side surfaces of the LED substrate, respectively.

Fig. 6 is a perspective view showing the base shown in fig. 4.

FIG. 7(a) is a cross-sectional view taken along line VIIa-VIIa of FIG. 4, and (b) is a cross-sectional view taken along line VIIb-VIIb of FIG. 4.

Fig. 8 is a diagram illustrating a main part structure of the liquid crystal display device.

Fig. 9 is a block diagram showing a configuration example of the panel control unit shown in fig. 8.

Fig. 10 is a block diagram showing a configuration example of the illumination control unit shown in fig. 8.

Fig. 11 is a flowchart showing the operation of each part of the liquid crystal display device.

Detailed Description

Hereinafter, preferred embodiments of an illumination device and a display device using the illumination device according to the present invention will be described with reference to the drawings. In the following description, a case where the present invention is applied to a transmissive liquid crystal display device will be described as an example. The dimensions of the components in the drawings do not actually indicate the actual dimensions of the components, the dimensional ratios of the components, and the like.

Fig. 1 is an exploded perspective view showing a liquid crystal display device using an illumination device according to an embodiment of the present invention, and fig. 2 is an exploded perspective view of the illumination device. In fig. 1, a liquid crystal display device 1 of the present embodiment includes a front frame 2, a liquid crystal panel 3 and an illumination device 4 of the present invention, which are provided in this order behind the front frame 2. The front frame 2 is configured to surround the display surface of the liquid crystal panel 3. The liquid crystal panel 3 is a transmissive liquid crystal display element including a liquid crystal layer and a pair of polarizing plates (not shown) provided so as to sandwich the liquid crystal layer. The liquid crystal panel 3 constitutes a display portion to be irradiated with planar light (illumination light) from the illumination device 4, and in the present embodiment, the liquid crystal panel 3 and the illumination device 4 are integrated as the transmissive liquid crystal display device 1.

Referring to fig. 2, the lighting device 4 includes: a housing 5 configured to surround a light emitting surface of the lighting device 4; and an optical sheet 6 and a chassis 7 that house a light emitting diode substrate (hereinafter, simply referred to as "LED substrate") 8, which are sequentially provided behind the housing 5, the light emitting diode substrate 8 being a light source substrate on which light emitting diodes as light emitting elements (light sources) are mounted. The optical sheet 6 includes a known optical sheet material such as a polarizing plate, a prism (condensing) sheet, or a diffusion sheet as necessary, and the display performance of the liquid crystal panel 3 is improved by appropriately increasing the brightness of the illumination light from the illumination device 4 by the optical sheet 6.

In the liquid crystal display device 1, a plurality of display regions and a plurality of illumination regions are set for the display surface of the liquid crystal panel 3 and the light-emitting surface of the illumination device 4, respectively. In the liquid crystal display device 1, backlight scanning driving for sequentially emitting a plurality of light-emitting diodes and area-active backlight driving for driving the light-emitting diodes to be lit in units of illumination areas are performed in parallel in accordance with information display on the liquid crystal panel 3 (details will be described later).

Here, referring to fig. 3, first, a display region in the liquid crystal panel 3 and an illumination region in the illumination device 4 will be specifically described.

Fig. 3 is a diagram illustrating a specific example of the illumination region and the display region set in the liquid crystal display device 1.

As illustrated in fig. 3, in the illumination device 4, a total of 54 illumination regions 1-1, 1-2, … …, 6-8, and 6-9 (hereinafter collectively referred to as "ba") arranged in a matrix of (6 × 9) are provided on a light-emitting surface (a surface of the optical sheet 6 surrounded by the frame 5 on the liquid crystal panel 3 side) which is arranged to face the liquid crystal panel 3 side and emits the illumination light. That is, for example, 9 illumination regions ba are set in a direction parallel to the lateral direction of the display surface of the liquid crystal panel 3, and 6 illumination regions ba are set in a direction parallel to the longitudinal direction of the display surface.

In the illumination regions 1-1, 1-2, … …, 6-8, and 6-9, light from a light-emitting diode package described later is made incident on 54 display regions (1), (2), … …, (53), and (54) (hereinafter collectively referred to as "pa") provided on the display surface of the liquid crystal panel 3. Each of the display regions pa includes a plurality of pixels. In the liquid crystal display device 1, as described above, the illumination region ba and the display region pa are basically set in a relationship of 1 to 1, and an area active backlight is configured to appropriately emit illumination light from the 1 illumination region ba for 1 display region pa in accordance with information to be displayed. Accordingly, in the liquid crystal display device 1, the plurality of illumination areas ba and the plurality of display areas pa are independently controlled, so that the contrast of the display surface can be increased and the moving image performance can be improved.

Note that, in fig. 3, the illumination areas ba and the display areas pa are shown as being divided by vertical lines and horizontal lines in order to clearly illustrate them, but actually, the illumination areas ba and the display areas pa are not divided by boundary lines or partition members. However, for example, a partition member may be provided above the base 7 to partition the illumination regions ba from each other.

Next, the lighting device 4 will be specifically described with reference to fig. 4 to 7.

Fig. 4 is a plan view showing a main part structure of the lighting device 4. Fig. 5 is a diagram illustrating the structure of the LED board 8 shown in fig. 4, and fig. 5(a), 5(b), and 5(c) are diagrams showing the mounting surface 8a, the rear surface 8b, and the side surfaces of the LED board 8, respectively. Fig. 6 is a perspective view showing the chassis 7 shown in fig. 4. FIG. 7(a) is a cross-sectional view taken along line VIIa-VIIa of FIG. 4, and FIG. 7(b) is a cross-sectional view taken along line VIIb-VIIb of FIG. 4.

As shown in fig. 4, in the lighting device 4, 3 and 6 rectangular LED substrates 8 are provided inside the chassis 7 along the horizontal direction and the vertical direction of fig. 4, respectively. As will be described later, these LED boards 8 are housed in the chassis 7 in a state where the LED boards 8 adjacent to each other in the lateral direction are electrically connected to each other. That is, the base 7 is provided with a 6-row LED substrate group including 3 LED substrates 8 electrically connected to each other. Each LED substrate 8 is provided with 2 rows of light emitting diode arrays each including a plurality of, for example, 6 light emitting diodes 9 arranged linearly, and a total of 12 light emitting diodes 9. In the illumination device 4, the number of LED substrates 8, the number, type, and size of the light-emitting diodes 9, and the like are appropriately selected in accordance with the size of the liquid crystal panel 3, the display performance such as luminance and display quality required for the liquid crystal panel 3, and the like.

Specifically, as shown in fig. 5, as the plurality of light emitting diodes 9, for example, so-called 3-in-1 (3in1) type light emitting diodes, which integrally constitute red, green, and blue light emitting diodes 9R, 9G, and 9B that emit red (R), green (G), and blue (B) light, respectively, are used as the mounting surface 8a of the LED board 8. The 3-in-1 type light emitting diodes 9 are a plurality of types of light emitting diodes having different emission colors, and constitute the light emitting diode package capable of mixing the light into white light. In the LED substrate 8, 2 or 4 light-emitting diodes 9 adjacent in the vertical direction and the horizontal direction are allocated to the 54 illumination regions ba.

As shown in fig. 5(a), 2 rows of light emitting diodes are provided on the mounting surface 8a in parallel with each other in the lateral direction. In each light emitting diode row, 6 light emitting diodes 9 are provided along a predetermined direction (lateral direction) and at predetermined intervals. This makes it possible to easily prevent the illumination light to the liquid crystal panel 3 from being uneven in brightness in the illumination device 4, and to easily improve the light emission quality of the illumination device 4.

As shown in fig. 5(b), in the LED substrate 8, a heat dissipation pattern 10 as a heat dissipation portion for dissipating heat generated by the light emitting diodes 9 is provided on a back surface 8b of the mounting surface 8a, in units of the light emitting diodes 9. That is, the heat dissipation pattern 10 is disposed at a position corresponding to the front and back surfaces (directly below) of the light emitting diode 9, and is configured to be able to efficiently conduct heat from the light emitting diode 9 to the heat dissipation pattern 10 through a through hole or the like provided inside the LED substrate 8 from the mounting surface 8a side to the back surface 8b side.

Further, on the rear surface 8b of the LED substrate 8, a heat transfer belt 12 as a heat transfer member for transferring heat from the heat dissipation pattern 10 to the base 7 side is attached along the lateral direction in units of 2 rows of heat dissipation pattern rows each including 6 heat dissipation patterns 10 linearly arranged. As the heat transfer belt 12, for example, a belt-shaped synthetic resin seal having high thermal conductivity such as acrylic resin is used, and the heat transfer belt 12 is provided so as to cover the heat dissipation pattern row. The heat transfer belt 12 conducts heat generated by the light emitting diode 9 to the base 7 side and radiates the heat to the outside (details will be described later).

Further, for example, 3 LED drivers 11 are mounted on the rear surface 8b of the LED board 8 so as to be arranged between 2 rows of heat dissipation pattern rows, that is, between 2 rows of light emitting diode rows mounted on the mounting surface 8 a. Each of the LED drivers 11 is a drive circuit element for driving the light emitting diode 9, and is formed of an IC into which predetermined electronic components such as a constant current circuit for supplying a constant current to the light emitting diode 9, a resistance element, and a capacitor are integrated. Each LED driver 11 is electrically connected to the 4 light-emitting diodes 9 through a through hole or the like provided in the LED substrate 8, and drives the connected 4 light-emitting diodes 9 based on an instruction signal from an illumination control unit described later. In the LED substrate 8, the light emitting diode 9 and the LED driver 11 as heat generation sources are separately mounted on the mounting surface 8a and the rear surface 8 b.

The rear surface 8b of the LED board 8 is provided with terminal portions 8c1 and 8c2 at the left and right ends parallel to each other. These terminal portions 8c1 and 8c2 are electrically connected to the LED driver 11 via a printed circuit not shown. The terminal portions 8c1 and 8c2 are electrically connected to the light emitting diode 9 directly through a through hole or the like or indirectly through the LED driver 11. The LED board 8 is configured to receive an instruction signal from an illumination control unit described later via the terminal portions 8c1 and 8c2, and to be supplied with power from a power supply not shown.

As shown in fig. 5(c), the LED substrate 8 is provided with the light emitting diode 9 and the LED driver 11 so as to protrude from the mounting surface 8a and the rear surface 8b, respectively. The light emitting diode 9 and the LED driver 11 are fixed to the printed circuits provided on the corresponding mounting surface 8a and the back surface 8b by soldering.

The base 7 is made of a metal having high thermal conductivity, such as aluminum, and radiates heat generated by the light emitting diode 9 to the outside. Specifically, as shown in fig. 6, the chassis 7 includes a frame-like frame 7a constituting a side wall portion of the chassis 7, and a flat-plate-like bottom plate 7b integrally provided on the frame 7a so as to close one end side (lower side) of the frame 7 a. Further, the base 7 is provided with: support parts 7c1, 7c2 for supporting the LED substrate 8; a connecting portion 7d for electrically connecting the 2 LED substrates 8 adjacent to each other in the lateral direction; and a connection part 7e for electrically connecting the LED substrate 8, the illumination control part 17 and the power supply. The base 7 is provided with 6 grooves 7f provided parallel to the lateral direction and 3 grooves 7g provided parallel to the longitudinal direction, and 12 connecting portions 7d and 6 connecting portions 7e are integrally provided on the bottom surface 7b of the base 7 at the intersection of the grooves 7f and 7 g.

Specifically, the thickness dimension, material, and the like of the bottom plate 7b of the base 7 are determined so as to have a desired rigidity (strength), and rectangular support portions 7c1, 7c2 are fixed to the bottom plate 7 b. In the support portion 7c1, the surface area of the light emitting surface side (upper side) is approximately 2 times the same surface area of the support portion 7c2, and the support portion 7c1 is configured to support 2 LED boards 8 provided adjacent to each other in the longitudinal direction. On the other hand, the uppermost and lowermost supporting portions 7c2 are configured to support the uppermost and lowermost LED boards 8, respectively. In the chassis 7, the grooves 7f are formed between the 2 support portions 7c1 adjacent in the longitudinal direction and between the support portions 7c1 and the support portions 7c2 adjacent in the longitudinal direction, and the LED board 8 is supported by the corresponding support portions 7c1 and 7c2 in a state where the LED driver 11 is disposed in the groove 7 f.

That is, as shown in fig. 7(a), for example, the LED substrate 8 is placed and supported on the support portions 7c1 and 7c2 via the heat transfer belt 12 in a state where the LED driver 11 is housed in the groove 7 f. The heat transfer tape 12 is provided with elasticity in addition to thermal conductivity, and the heat transfer tape 12 is configured to improve the adhesion between the heat dissipation pattern 10 of the LED substrate 8 and the support portions 7c1 and 7c 2. The heat transfer belt 12 is provided with adhesiveness on both surfaces, that is, the surface on the LED substrate 8 side and the surfaces on the support portions 7c1 and 7c2 sides, and can be in surface contact with the back surface 8b of the LED substrate 8 and the surfaces of the support portions 7c1 and 7c2 in a reliable and stable state.

As described above, since the heat transfer belt 12 is configured to have improved adhesion to the LED substrate 8 and the base 7, and to be in surface contact with the LED substrate 8 and the base 7 in a reliable and stable state, in the illumination device 4 of the present embodiment, it is possible to prevent as much as possible a decrease in the heat conduction efficiency from the LED substrate 8 side to the base side by the heat transfer belt 12. As a result, in the lighting device 4 of the present embodiment, the heat generated by the light emitting diodes 9 can be quickly and efficiently dissipated to the outside of the chassis 7 via the heat dissipation pattern 10, the heat transfer belt 12, the support portions 7c1, 7c2, and the bottom plate 7 b. Therefore, in the illumination device 4 of the present embodiment, it is possible to prevent the amount of light emitted by the light emitting diode 9 from varying due to a variation in ambient temperature, and it is possible to configure the illumination device 4 with excellent light emission quality more easily.

In addition to the above description, the heat dissipation pattern 10 of the LED board 8 may be directly in contact with the supporting portions 7c1 and 7c2 of the chassis 7 without using the heat transfer sheet 12. Instead of the heat transfer sheet 12, an adhesive having thermal conductivity which becomes a rubber elastic body after curing may be used. Further, for example, a heat sink may be provided on the bottom plate 7b of the chassis 7 to improve the heat dissipation capability of the chassis 7, or a heat dissipation mechanism capable of forcibly cooling the heat of the light emitting diode, such as a fan or a water tank through which water flows, may be provided on the back side of the bottom plate 7 b.

Further, the respective connecting portions 7d of the bases 7 and 12 are integrally attached to the bottom plate 7b of the base 7 so as to be disposed between the 2 LED boards 8 adjacent in the lateral direction. That is, as shown in fig. 6, the 6 connecting portions 7d are linearly provided at predetermined intervals inside the grooves 7g on the left and center in the figure among the 3 grooves 7g provided in parallel to the longitudinal direction.

As illustrated in fig. 7(b), each of the connecting portions 7d includes a metal film 7d1 and a support 7d2 that are electrically connected to the terminal portion 8c2 of the LED board 8, and the support 7d2 is formed using an elastic body such as a rubber material and supports the metal film 7d1 integrally with the metal film 7d 1. The support 7d2 is attached to the bottom plate 7b by a fixing means (not shown) such as a screw or an adhesive, and each connecting portion 7d is integrally attached to the bottom plate 7b of the base 7 in an elastically deformable state.

In each of the connecting portions 7d, the terminal portions 8c1 and 8c2 of 2 LED boards 8 adjacent in the lateral direction are placed on the metal film 7d1, whereby the LED boards 8 can be electrically connected to each other. Thus, in the illumination device 4 of the present embodiment, the assembly operation of the LED substrate 8 to the chassis 7 can be performed easily and with high accuracy, and the productivity of the illumination device 4 can be improved. In the illumination device 4 of the present embodiment, since the LED substrates 8 are electrically connected to each other without using an electric wire such as an FPC or a dedicated connector, a plurality of LED substrates 8 can be accommodated in the chassis 7 without causing a dead space as shown in fig. 4, and the illumination device 4 can be easily prevented from being enlarged.

The 6 connecting portions 7e are linearly provided at predetermined intervals inside the right groove 7g in fig. 6. Similarly to the connection portion 7d, each of the connection portions 7e is integrally attached to the bottom plate 7b of the base 7 in a state electrically insulated from the frame body 7a and the bottom plate 7b and in a state elastically deformable with respect to the bottom plate 7 b. Further, the other end of an FPC (not shown) having one end connected to a lighting control unit (described later) and the power supply is electrically connected to each connection portion 7e, and outputs the instruction signal and supplies power to the LED substrate 8.

As described above, since the connecting portions 7d and 7e are integrally provided in the chassis 7 in an elastically deformable state, electrical connection with the terminal portions 8c1 and 8c2 can be performed in a more reliable state. Further, since the connecting portions 7d and 7e are elastically deformable with respect to the chassis 7, even when the LED substrate 8 is fixed to the chassis 7 by the fixing method such as the screws, the height dimension of the LED substrate 8 connected by the connecting portions 7d and 7e from the bottom plate 7b of the chassis 7 can be easily matched to a predetermined value. As a result, in the illumination device 4 of the present embodiment, the accuracy of assembling the LED substrate 8 and the base 7 can be easily improved.

In addition to the above description, a connection member configured to be detachable from the base 7 may be used instead of the connection portions 7d and 7 e. Further, terminal portions are provided on the mounting surface 8a side and the rear surface 8b side of the LED substrate 8, and 2 LED substrates can be electrically connected to each other without passing through a connecting portion.

Next, the backlight scanning drive and the area active backlight drive of the liquid crystal display device 1 according to the present embodiment will be specifically described with reference to fig. 8 to 11.

Fig. 8 is a diagram illustrating a configuration of a main part of the liquid crystal display device 1. Fig. 9 is a block diagram showing a configuration example of the panel control unit shown in fig. 8, and fig. 10 is a block diagram showing a configuration example of the illumination control unit shown in fig. 8. Fig. 11 is a timing chart showing the operation of each part of the liquid crystal display device 1.

In fig. 8, the control unit 13 receives an image signal from outside the liquid crystal display device 1 via a signal source (not shown) such as a TV (receiver) or a PC. The control unit 13 substantially controls the driving of the liquid crystal panel 3 by using the input image signal. The control unit 13 is configured to substantially perform drive control of the illumination device 4 using the input image signal.

Specifically, the control unit 13 includes: a panel control unit 14 for driving and controlling the liquid crystal panel 3in units of pixels using the image signal; an illumination control unit 15 for controlling the driving of the light emitting diodes 9 of the illumination device 4 by using the image signal; and a frame memory 16 configured to store frame-unit display data included in the image signal. The control unit 13 is configured to input a dimming instruction signal from a remote controller (not shown) attached to the liquid crystal display device 1, and the illumination control unit 15 changes the power supplied to the light emitting diode 9 based on the input dimming instruction signal.

The panel control unit 14 is configured to output respective instruction signals to the source driver 17 and the gate driver 18. The panel control unit 14 is configured to notify the luminance value of each of the illumination regions ba from a regional crosstalk correction unit, which will be described later, provided in the illumination control unit 15, and to correct the instruction signal to the source driver 17 to a signal reflecting the luminance value of each of the illumination regions ba notified, and then to output the signal from the panel control unit 14 to the source driver 17.

The source driver 17 and the gate driver 18 are driving circuits for driving a plurality of pixels provided in the liquid crystal panel 3in units of pixels, and a plurality of signal lines S1 to SM (M is an integer of 2 or more) and a plurality of control lines G1 to GN (N is an integer of 2 or more) are connected to the source driver 17 and the gate driver 18, respectively. The signal lines S1 to SM and the control lines G1 to GN are arranged in a matrix, and the regions of the plurality of pixels are formed in the respective regions divided in the matrix. The plurality of pixels include a red pixel Pr, a green pixel Pg, and a blue pixel Pb. The red, green, and blue pixels Pr, Pg, and Pb are sequentially arranged in parallel with the control lines G1 to GN in this order, for example.

The control lines G1 to GN are connected to the gates of the switching elements 19 provided for the respective pixels. On the other hand, the source of the switching element 19 is connected to each of the signal lines S1 to SM. A pixel electrode 20 provided for each pixel is connected to the drain of each switching source 19. In each pixel, the common electrode 21 is configured to face the pixel electrode 20 with the liquid crystal layer provided in the liquid crystal panel 3 interposed therebetween.

Referring to fig. 9, the panel control unit 14 is provided with an image processing unit 22 and a display data correction calculation unit 23, and is configured to generate respective instruction signals to the source driver 17 and the gate driver 18 using the input image signal. That is, the image processing unit 22 generates an instruction signal for the gate driver 18 based on the display data of the image signal stored in the frame memory 16 and outputs the instruction signal to the gate driver 18. Thus, the gate driver 18 sequentially outputs gate signals for turning on the gates of the corresponding switching elements 17 to the control lines G1 to GN based on the instruction signals from the image processing unit 22. The image processing unit 22 generates an instruction signal to the source driver 17 based on the display data and outputs the instruction signal to the display data correction arithmetic unit 23.

The display data correction arithmetic section 23 receives not only the instruction signal to the source driver 17 from the image processing section 22 but also the luminance value of each illumination area ba from the area crosstalk correction section. The luminance values of the illumination areas ba are luminance values corrected using crosstalk values described later, and are values in which the influence of crosstalk of light from the surrounding illumination areas ba is taken into consideration. The display data correction arithmetic unit 23 corrects the instruction signal to the source driver 17 on a pixel-by-pixel basis using the luminance value of each illumination area ba, generates a new instruction signal, and outputs the new instruction signal to the source driver 17. Thus, the source driver 17 appropriately outputs a voltage signal (gradation voltage) for specifying the luminance (gradation) of the information displayed on the display surface to the signal lines S1 to SM based on the instruction signal from the display data correction arithmetic section 23.

Referring to fig. 10, the illumination control unit 15 is provided with an area luminance calculation unit 24, an area crosstalk correction unit 25, and an LED drive control unit 26. The illumination control unit 15 sequentially drives the 6-row LED substrate group to be lit up in accordance with an input image signal (details will be described later).

The area luminance calculation unit 24 acquires, for each of the illumination areas ba, luminance information of pixels included in the corresponding display area pa from the input image signal. The area luminance calculating unit 24 performs luminance calculating processing for calculating and obtaining the luminance value of each of the red, green, and blue colors in each of the illumination areas ba, using the acquired luminance information of the pixels. The area luminance calculating section 24 is configured to output the obtained luminance values of the red, green, and blue colors in each illumination area ba to the area crosstalk correcting section 25.

The luminance values of the respective colors of red, green, and blue in the plurality of illumination areas ba from the area luminance calculating section 24 are input to the area crosstalk correcting section 25. The area crosstalk correcting unit 25 is configured to determine a crosstalk value of light incident from the peripheral illumination area ba with respect to the corresponding display area pa for each illumination area ba, and perform area crosstalk correction processing for correcting the luminance values of the plurality of illumination areas ba based on the determined crosstalk value. The local crosstalk correcting unit 25 performs the above-described local crosstalk correction process for each of red, green, and blue colors.

The LED drive control section 26 is configured to perform the above-described backlight scanning drive for sequentially emitting the plurality of illumination regions ba in accordance with the information display on the liquid crystal panel 3. In the backlight scanning drive, the corresponding light emitting diodes 9 are sequentially driven to be turned on so that the plurality of illumination regions ba are sequentially arranged in the predetermined lighting direction and the plurality of illumination regions ba and at least one of the illumination regions ba adjacent to each other in the lighting direction emit light simultaneously for a predetermined repetition period. Thus, in the illumination device 4 of the present embodiment, the backlight scanning drive and the area-active backlight drive are performed in parallel.

Specifically, in the illumination device 4 of the present embodiment, as shown in fig. 11I to VI, a group of 6 rows of LED substrates in which the LED substrates 8 adjacent in the lateral direction are electrically connected to each other is sequentially driven to be lit along the longitudinal direction of the display surface as the lighting direction. Each of the LED substrate groups is configured to be lit during an LED lighting period in which the same time interval is set, and to be simultaneously lit and driven with respect to the LED substrate groups adjacent in the vertical direction between the repetition periods.

In other words, in embodiment 4, in the light emitting diodes 9 shown in fig. 4, 36 light emitting diodes 9 mounted on the 3 LED boards 8 disposed on the uppermost side in fig. 4 are simultaneously driven to be lit, and therefore, illumination light is simultaneously emitted from the illumination regions 1-1, … …, 1-9 (fig. 3) disposed corresponding to the light emitting diodes 9 to the corresponding display regions (1), … …, (9) (fig. 3). Then, when the illumination light from the illumination regions 1-1, … …, and 1-9 is irradiated, since the 36 light emitting diodes 9 mounted on the 3 LED substrates 8 arranged in the second stage from the upper side are simultaneously lighted and driven, the illumination light is simultaneously emitted from the illumination regions 2-1, … …, and 2-9 (fig. 3) to the corresponding display regions (10), … …, and 18) (fig. 3). Then, according to the timing indicated by the LED lighting period in fig. 11, the illumination regions ba provided parallel to the lateral direction of the display surface emit light simultaneously with each other, and the illumination light is emitted to the corresponding display regions pa.

In the illumination device 4 of the present embodiment, the 1-frame period and the scanning period are set at the same time interval, and the liquid crystal response period and the LED lighting period are set within the 1-frame period. In the illumination device 4 of the present embodiment, all the light emitting diodes 9 are turned off in a period other than the LED lighting period, and a black insertion period for sequentially displaying the display regions pa of the display surface in black gradation is provided in accordance with the turning-off operation in the illumination region ba. Thus, in the liquid crystal display device 1 of the present embodiment, even when moving image display is performed, it is possible to reliably prevent the display quality from being lowered.

In the illumination device 4 of the present embodiment configured as described above, a plurality of light emitting diodes (light emitting elements) 9 and LED drivers (driving circuit elements) 11 are provided in a distributed manner on the mounting surface 8a and the rear surface 8b of the LED board (light source board) 8, respectively. Thus, in the illumination device 4 of the present embodiment, even when the number of the light emitting diodes 9 is increased, unlike the above-described conventional example, it is possible to suppress the mutual influence of the heat generated by the light emitting diodes 9 and the heat generated by the LED driver 11. As a result, in the illumination device 4 of the present embodiment, unlike the above-described conventional example, it is possible to prevent the ambient temperature of the plurality of light emitting diodes 9 from increasing due to heat from the LED driver 11, and it is possible to prevent the light emission efficiency of each light emitting diode 9 from decreasing. Therefore, in the present embodiment, the light emission quality of the illumination device 4 can be improved.

In addition, in the present embodiment, as described above, even when the number of the light emitting diodes 9 is increased, since the lighting device 4 having improved light emission quality is used, the high-performance liquid crystal display device 1 having high luminance and excellent display quality can be easily configured.

In the present embodiment, the heat dissipation pattern (heat dissipation portion) 10 is provided on the rear surface 8b of the LED board 8 in units of the light-emitting diodes 9, whereby heat generated by the plurality of light-emitting diodes 9 is efficiently conducted from the mounting surface 8a side to the chassis 7 side, and therefore heat from the light-emitting diodes 9 can be efficiently dissipated to the outside. As a result, in the present embodiment, the light emission quality of the illumination device 4 can be easily improved. In addition, since the heat dissipation patterns 10 are provided for each of the light emitting diodes 9 in this manner, as shown in fig. 11, even when the 6-row LED substrate group is sequentially driven for lighting, heat generated by the light emitting diodes 9 included in each of the light emitting diode rows can be appropriately dissipated. As a result, in the illumination device 4 of the present embodiment, even when the backlight scanning drive and the area active backlight drive are performed in parallel, the plurality of light emitting diodes 9 can be operated stably, and the light emission quality can be prevented from being lowered.

The above embodiments are merely illustrative and not intended to limit the present invention. The technical scope of the present invention is defined by the scope of the claims, and all modifications within the scope equivalent to the structure described in the claims are also included in the technical scope of the present invention.

For example, although the present invention has been described as being applied to a transmissive liquid crystal display device in the above description, the illumination device of the present invention is not limited to this, and can be applied to various display devices including a non-light-emitting display unit that displays information such as images and characters by light from a light source. Specifically, the illumination device of the present invention can be suitably used for a transflective liquid crystal display device or a projection display device using the liquid crystal panel for rear projection of a shutter or the like.

In addition to the above description, the present invention can also be used as an illumination device for an observation box (illuminator) for irradiating an roentgen radiograph with light, a light box (light box) for irradiating a photographic film or the like with light to make it easy to recognize, and a light-emitting device for illuminating an advertisement or the like installed on a signboard, a wall surface in a station area, or the like.

In the above description, a case will be described in which an LED substrate provided with 2 LED arrays each including 6 light emitting diodes arranged linearly is used, and a 6-array LED substrate group including 3 LED substrates arranged linearly and electrically connected to each other is used. However, in the present invention, as long as a driving circuit element for driving the light emitting element is provided on the back surface of the mounting surface in the light source substrate in which the plurality of light emitting elements are mounted on the mounting surface, the configuration of the light source substrate (including the number and kinds of the light emitting elements to be provided), the number of the light source substrates to be provided, the connection method, and the like are not limited at all.

However, as described in the above embodiment, when a plurality of light emitting element rows are mounted on the mounting surface of the light source substrate, in the case where the drive circuit element is provided on the back surface of the mounting surface so as to be disposed between the plurality of light emitting element rows, it is possible to more reliably suppress the influence of the heat generated by each of the light emitting element and the drive circuit element on each other, and it is possible to easily improve the light emission quality of the lighting device. In addition, when only 1 row of light-emitting element rows is mounted on the mounting surface, the heat dissipation pattern can be preferably arranged at a position on the front and back surfaces (directly below) of the corresponding light-emitting diode by mounting the driving circuit element on the back surface at a position other than a position directly below each light-emitting element included in the light-emitting element rows.

In addition, as in the above-described embodiments, when the light emitting element is a light emitting diode, it is preferable in that a lighting device with low power consumption and excellent environmental performance can be easily configured.

In the above description, the case where a plurality of 3-in-1 type light emitting diodes are used, which are integrated RGB light emitting diodes, has been described, but the light emitting diode of the present invention is not limited to this. R, G, B may be used as individual light-emitting diodes, a white (W) light-emitting diode emitting white light, or a so-called 4-in-1 (4in1) light-emitting diode in which 4 light-emitting diodes such as RGBW and GRGB are integrated. Further, a light emitting diode of a color other than RGBW may be added. In this case, color addition is also required in the pixel structure of the liquid crystal panel, and a wider range of colors can be reproduced. Specific examples of the additional color include yellow and magenta.

However, as described in the above embodiments, in the case of using a plurality of types (for example, RGB) of light emitting diodes which emit light of different colors and can mix the light into white light, it is preferable in that the color purity corresponding to the light emission colors of the plurality of types of light emitting diodes can be improved as compared with the case of using only white light emitting diodes. Further, it is preferable that an illumination device having excellent light emission quality or a display device having excellent display quality be easily configured.

In the above description, the case where the directly-below type illumination device is configured has been described, but the present invention is not limited to this, and can be applied to, for example, an edge-light type illumination device in which a single light guide plate is provided below the light emitting surface of the illumination device and a plurality of light source substrates are arranged in parallel with at least one of the 4 sides surrounding the light guide plate, or another type of illumination device such as a tandem type in which a light guide plate is provided for each light emitting element. Further, even when the present invention is applied to a tandem-type lighting device or the like in which an optical member such as a light guide plate needs to be provided on the mounting surface of the light source substrate, as shown in fig. 5, in the present invention, the provision of an electrical component or the like other than the light emitting element such as the connector is omitted on the mounting surface side of the light source substrate, and therefore, the provision of the optical member can be easily performed, and the lighting device can be easily made thin.

In addition to the above description, the present invention can be applied to: for example, an illumination device configured to determine the light emission amounts from the light emitting elements included in each of a plurality of illumination regions on an illumination region-by-illumination region basis based on an input image signal and to perform all of the uniform flash drives for simultaneously turning on or off all of the light emitting elements; or, in order to prevent flicker and luminance unevenness from occurring in the plurality of light emitting elements linearly arranged on the light source substrate, the lighting device is configured such that the lighting drive of the adjacent 2 light emitting elements is performed in a state in which the on/off phases of the PWM dimming are shifted from each other for the adjacent 2 light emitting elements.

Industrial applicability

The present invention is useful for an illumination device capable of improving light emission quality even when the number of light-emitting elements to be provided is increased, and a high-performance display device using the illumination device.

Claims (10)

1. An illumination device including a light emitting element, and a light source substrate having a mounting surface on which the light emitting element is mounted, characterized in that:

a plurality of the light emitting elements are provided on a mounting surface of the light source substrate,

a drive circuit element for driving the light emitting element is provided on the back surface of the mounting surface.

2. A lighting device as recited in claim 1, wherein:

a plurality of light emitting element rows including a plurality of light emitting elements arranged in a predetermined direction and at predetermined intervals are provided on the mounting surface of the light source substrate,

a driving circuit element for driving the light emitting elements is provided on the back surface of the mounting surface, and the driving circuit element is disposed between the plurality of light emitting element rows.

3. A lighting device as recited in claim 1 or claim 2, wherein:

which comprises a base for accommodating the light source substrate and,

the light source substrate is provided with a heat dissipation portion for dissipating heat generated by the light emitting element on the rear surface thereof, and the heat from the heat dissipation portion is dissipated to the outside through the chassis.

4. A lighting device as recited in claim 3, wherein:

a heat transfer member is provided between the base and the heat dissipation portion.

5. The illumination device of claim 4, wherein:

the heat transfer member is imparted with elasticity.

6. A lighting device as recited in claim 4 or 5, wherein:

the heat transfer member is provided with adhesiveness.

7. A lighting device as recited in any one of claims 1-6, wherein:

the light emitting element is a light emitting diode.

8. A lighting device as recited in any one of claims 1-6, wherein:

the light emitting elements are formed of a plurality of types of light emitting diodes which emit light of different colors and can be mixed into white light.

9. A lighting device as recited in any one of claims 1-6, wherein:

the light emitting element uses a plurality of types of light emitting diodes having different emission colors from each other, and includes a plurality of sets of light emitting diode packages capable of mixing colors into white light,

the plurality of sets of light emitting diode packages are provided on the mounting surface along the predetermined direction and at predetermined intervals.

10. A display device provided with a display unit, characterized in that:

the display unit is irradiated with light from the lighting device according to any one of claims 1 to 9.