WO2013065116A1 - Backlight device and liquid crystal display device utilizing same - Google Patents

Abstract

The present invention is a backlight device that has a base chassis and a backlight unit provided on the base chassis and comprising multiple backlight blocks, wherein each backlight device is equipped with multiple LEDs for emitting light in an emission direction parallel to the light emission plane of the backlight unit, an LED substrate for mounting the LEDs that is provided parallel to and on the top surface side of a reflective sheet, and an LED cover that is attached to the LED substrate and covers the LEDs from the top in the Z-direction and from both sides in the X-direction in order to form housing sections for housing the LEDs in conjunction with the LED substrate, and is characterized in that the backlight device is configured such that the light from each of the light sources is led to a light exit plane by causing the light to transmit through an optical component while the light is repeatedly reflected inside a space that is formed between the optical component and the reflective member.

Description

Backlight device and liquid crystal display device using the same

The present invention relates to a backlight device and a liquid crystal display device using the same, and more particularly, to a backlight device using a side view type LED (Light Emitting Diode) as a light source and a liquid crystal display device using the same.

Since the liquid crystal display device does not emit light by itself, a backlight device is arranged on the back of the liquid crystal display panel. In a backlight device used for a liquid crystal display device having a relatively large screen such as a television display device, a fluorescent tube has been used as a light source (see Patent Document 1).

Patent Document 1 discloses an edge light type (side view type) backlight device and an invention in which the backlight device is applied to a liquid crystal display device having a liquid crystal panel 10. In the backlight device of Patent Document 1, in order to transmit light toward the liquid crystal panel, a light guide plate disposed so as to overlap the liquid crystal panel, a fluorescent tube as a light source disposed on a side portion of the light guide plate, It has a condenser that collects the light from the fluorescent tube in a relatively small angle range and enters the light toward the light guide plate. In addition, the fluorescent tube has a U-shaped reflector in its cross section having an internal reflection layer.
The light guide plate of Patent Document 1 is made of a transparent plate such as an acrylic resin. A diffusion sheet is provided on one surface (hereinafter, the liquid crystal display panel side is referred to as an upper surface), and a diffusion reflection layer (reflection) is formed on the lower surface. Sheet) is provided. The diffuse reflection layer is obtained by providing diffusion dots in a predetermined pattern on the lower surface of the light guide plate. The diffusion dots have different areas depending on the distance from the light source of the light guide plate, thereby making it possible to obtain uniform brightness over the entire surface of the light guide plate as is well known.

JP-A-6-174929

In Patent Document 1, a light guide plate, a condenser, a reflector, and the like are used, and the number of parts is large. For this reason, in the backlight device and the liquid crystal display device using the backlight device, the component cost is high. In addition, since a fluorescent tube is used, power consumption is large.
In addition, the fluorescent tube has a heavy load on the global environment because mercury vapor is sealed inside. Therefore, the use tends to be prohibited in some areas such as Europe.
Thus, in recent backlight devices, LEDs (Light Emitting Diodes) are being used as light sources instead of fluorescent tubes. Further, it has been studied to eliminate the light guide plate for guiding the light emitted from the side view type LED light source to the diffuser plate by totally reflecting and scattering the light.

In a backlight device of a liquid crystal display device using an LED as a light source, an optical system that uses the entire liquid crystal display device from the LED as a surface light source is required. A backlight device used in a large-screen liquid crystal display device generally has a structure in which the backlight device is divided into a plurality of backlight blocks. And it is necessary to make light emitted from each LED in each backlight block uniformly reach within the backlight block.

However, the light incident from the light source travels through the air layer due to total reflection or the like, is scattered by the diffusion / light guiding pattern provided on the front surface of the backlight device, and is emitted from the front surface of the backlight device. At this time, the intensity of light locally increases in the vicinity of the light source (the light from the LED is in the vicinity of the emitted light) compared to the other parts. As a result, so-called luminance unevenness occurs in the light emitted from the front surface of the backlight device.
FIG. 1 is a diagram showing the result of simulating the luminance distribution of light from the emitted light to the next LED. The horizontal axis represents the traveling direction of the light emitted from the LED light source, and the vertical axis represents the luminance (logarithm) incident on the diffusion plate on the front surface of the backlight device. FIG. 2 is a diagram showing the result of simulating the luminance distribution observed on the diffusion plate on the front surface of the backlight device. FIG. 2 is a distribution diagram in which backlight blocks are indicated by contour lines of luminance values, and regions P1 and P2 are portions having the highest luminance values. Reference numeral 210 denotes an emission direction of light from the LED light source. And it shows that the luminance value is lowered as the number of contour lines increases. The region P1 is a place where the light emitted from the LED 7-1 is directly applied to the diffusion plate, and the region P2 is a place where the light emitted from the LED 7-2 is directly applied to the diffusion plate.

In FIG. 1, the peak value P1 of the luminance value is generated by the light emitted from the LED 7-1. The luminance decreases as the distance from the LED 7-1 increases, and becomes the lowest luminance value L3 near the back of the next LED 7-2. On the diffuser plate of the backlight device, a dot-like pattern is formed by printing or the like so that the emitted light from the LEDs 7-1 and 7-2 is reduced in luminance unevenness. By changing the size and density of the dot-shaped pattern as the distance from the vicinity of the emitted light increases, the luminance unevenness is improved. For example, by making the luminance distribution close to the linear characteristic as shown by the dotted line L2, according to the dot-like pattern described above, a uniform luminance distribution with less uneven luminance as shown by the alternate long and short dash line L3 can be realized. . However, in order to achieve such a luminance distribution, the above dot-like pattern is complicated and it is necessary to increase the print film thickness. To form such a print pattern, printing is performed a plurality of times. Since the process is necessary, the positional deviation of printing is likely to occur.
Furthermore, in reality, strong light is output in the vicinity of the emitted light from the LED, and as a result, uneven brightness occurs as shown in FIG.

An object of the present invention is to provide a backlight device and a liquid crystal display device with little luminance unevenness in view of the above problems.

In order to achieve the above object, a backlight device according to the present invention is a backlight device for irradiating light from an emission surface. The backlight device includes a base chassis and a plurality of backlights on the base chassis. Each of the backlight blocks is provided on the back side of the backlight block and on the base chassis, and is provided to face the reflection sheet. A plate-like diffusion plate arranged at a predetermined distance from the reflecting member in a direction orthogonal to the light irradiation surface of the backlight, and the back arranged in a space between the diffusion plate and the reflection sheet. A plurality of LEDs (Light Emitting Diodes) that emit light in the emission direction parallel to the light irradiation surface of the light unit, and the LEDs are mounted on the reflection sheet. In parallel, the LED board provided on the upper surface side of the reflecting sheet, and attached to the LED board, covering the upper side and both side surfaces of the LED, and configured to accommodate the LED together with the LED board A backlight device characterized by comprising an LED cover.

In the backlight device of the first feature of the present invention, the second feature of the present invention is that the LED is a side view type LED.

In the backlight device according to the first aspect of the present invention, a projection for holding a predetermined distance between the base chassis and the diffusion plate is provided on the upper side in the Z direction of the LED cover. Three features.

In the backlight device according to the third feature of the present invention, a fourth feature of the present invention is that the LED cover and the protrusion are integrated.

In the backlight device according to the first feature of the present invention, a pattern having a predetermined area for shielding light emitted above the LED is provided on the diffusion plate directly above the LED. It is characterized by.

In the backlight device according to the first feature of the present invention, a sixth feature of the present invention is that the rear portion of the LED cover is an inclined surface.

In the backlight device according to the first feature of the present invention, the LED cover has a seventh feature of the present invention in which a ridge is provided on the upper side of the LED in the Z direction and in the emission direction.

In the backlight device according to the seventh feature of the present invention, the eighth feature of the present invention is that the bag has a shape divided for each of the accommodating portions.

Further, the backlight device of the present invention is a backlight device for irradiating light from an emission surface, wherein the backlight device includes a base chassis and a backlight unit including a plurality of backlight blocks on the base chassis. Each of the backlight blocks is provided on the back side of the backlight block and on the base chassis, and is provided to face the reflection sheet. A plate-like diffuser plate disposed at a predetermined interval in a direction orthogonal to the light irradiation surface of the light source, and parallel to the light irradiation surface of the backlight unit disposed in a space between the diffusion plate and the reflection sheet A plurality of LEDs (Light Emitting Diodes) that emit light in a light emitting direction, and the LEDs are mounted, parallel to the reflective sheet, A ninth feature of the present invention includes an LED substrate provided on the upper surface side and an LED cover attached to the LED substrate and covering the upper side of the LED.

In order to achieve the above object, the liquid crystal display device of the present invention uses a liquid crystal panel and the backlight devices of the first to ninth features of the present invention as the tenth feature of the present invention. To do.

According to the present invention, it is possible to provide a backlight device capable of improving the utilization efficiency of light from a light source and obtaining a high-quality image, and a liquid crystal display device using the backlight device.

It is a figure which shows the result of having simulated the luminance distribution of the light from LED to the next LED. It is a figure which shows the result of having simulated the luminance distribution observed with the diffuser plate of the front surface of a backlight apparatus. It is a perspective view which shows the external appearance of one Example of the video display apparatus of this invention. FIG. 4 is an exploded perspective view illustrating an arrangement configuration of an example of main components in a display unit 310 of the video display device 300 illustrated in FIG. 3. It is the schematic diagram which demonstrated one Example of arrangement | positioning of LED, and the emission direction of light seeing a part of backlight part from the diffusion plate or the liquid crystal panel side. It is a fragmentary sectional view of the optical axis direction of LED7 of the backlight apparatus which concerns on 1st Example of this invention, and its peripheral part. It is a fragmentary sectional view of the optical axis direction of LED7 of the backlight apparatus based on 2nd Example of this invention, and its peripheral part. FIG. 6 is a partial perspective view of a backlight device and a peripheral portion thereof according to a second embodiment of the present invention. It is a fragmentary sectional view of the optical axis direction of LED7 of the backlight apparatus which concerns on 3rd Example of this invention, and its peripheral part. FIG. 6 is a partial perspective view of a backlight device and a peripheral portion thereof according to a third embodiment of the present invention. It is a fragmentary sectional view of the optical axis direction of LED7 of the backlight apparatus based on 4th Example of this invention, and its peripheral part. FIG. 6 is a partial perspective view of a backlight device and a peripheral portion thereof according to a fourth embodiment of the present invention. It is a fragmentary perspective view of the modification of 4th Example of the LED cover used for the backlight apparatus of this invention. It is a fragmentary perspective view of 5th Example of the LED cover used for the backlight apparatus of this invention. It is a figure which shows the result of having simulated the luminance distribution observed with the diffusion plate of the front surface of the backlight apparatus of this invention when the LED cover of FIG. 13 is used. It is a figure which shows the result of having simulated the luminance distribution observed with the diffusion plate of the front surface of the backlight apparatus of this invention when the LED cover of FIG. 12 is used. It is a figure which shows the result of having simulated the luminance distribution observed with the diffusion plate of the front surface of the backlight apparatus of this invention when the LED cover of FIG. 12 is used. It is a side view of the LED cover which concerns on 6th Example of this invention. It is a perspective view of the LED cover which concerns on 6th Example of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In addition, the following description is for describing one embodiment of the present invention, and does not limit the scope of the present invention. Accordingly, those skilled in the art can employ embodiments in which these elements or all of the elements are replaced with equivalent ones, and these embodiments are also included in the scope of the present invention.
In this document, components having common functions are denoted by the same reference numerals in the description of each drawing including those already described with reference to FIGS. 1 and 2 to avoid duplication of description as much as possible.

First, an overall configuration of a video display device to which the backlight device according to the present embodiment is applied will be outlined with reference to FIGS. 3 to 7, and thereafter, means for solving the problems of the present invention will be described. An embodiment will be described.

FIG. 3 is a perspective view showing the external appearance of an embodiment of the video display device of the present invention. In FIG. 3, a television receiver is cited as the video display device. Reference numeral 300 denotes a video display device, 310 denotes a display unit of the video display device 300, and 320 denotes a stand of the video display device 300.
In FIG. 3, the video display device 300 is a liquid crystal display device using a liquid crystal panel. The video display device 300 includes a display unit 310 and a stand unit 320 that supports the display unit 310 from below. . Inside the display unit 310, as will be described later, a liquid crystal panel and a backlight device which are display devices are provided.

FIG. 4 is an exploded perspective view showing an arrangement configuration of one embodiment of main components in the display unit 310 of the video display device 300 shown in FIG. Reference numeral 1 denotes a liquid crystal panel, 3 denotes a backlight unit, 4 denotes a backlight block, 22 denotes a diffusion plate, 402 denotes an optical sheet, 403 denotes an emission surface, and 460 denotes a lower chassis. The diffusion plate 22 is composed of one or more sheets. The backlight device includes the backlight unit 3, the diffusion plate 22, and the optical sheet 402.
In FIG. 4, main parts constituting the display unit 310 of the video display device 300 are the liquid crystal panel 1 and the backlight unit 3 for irradiating light from the back surface of the liquid crystal panel 1. Here, the light emitted from the backlight unit 3 travels as indicated by an arrow A410, and reaches the liquid crystal panel 1 as indicated by an arrow B420 through the diffusion plate 22, the optical sheet 402, and the like.
A video signal is supplied to the liquid crystal panel 1 and the light transmittance of the liquid crystal elements constituting each pixel is controlled based on the video signal. The light incident on the liquid crystal display panel 1 in accordance with the arrow B420 is spatially modulated by each pixel of the liquid crystal panel 1 to form an optical image, which is displayed on the exit surface 403 as an image. That is, the light incident on the liquid crystal panel 1 is emitted as image light as indicated by an arrow C430. Arrows 410, 420, and 430 are in the same direction as the Z direction (front) side.
The backlight unit 3 includes a backlight block 4 or a combination of a plurality of the backlight blocks 4, and the entire backlight unit 3 is attached to and held by the lower chassis 460.

FIG. 5 is a schematic diagram illustrating an example of the arrangement of the LEDs 7 and the light emission direction when a part of the backlight unit 3 is viewed from the emission surface 403 (liquid crystal panel 1) side.
As shown in FIG. 5, the LED 7-1, LED 7-2, LED 7-3,..., And LED 7 are arranged from the bottom to the top in the same direction as the light emission direction of the LED in parallel with the Y direction. . The LED 7-1, LED 7-2, LED 7-3,... Are similarly arranged in the X direction. The LED 7-1 is provided in the lowermost backlight block 4, the LED 7-2 is provided in the next-stage backlight block 4, and the LED 7-3 is provided in the next-stage backlight block 4. . Thus, the backlight unit 3 is configured by combining a plurality of backlight blocks 4.
In addition, about the arrangement | positioning of LED7 and the light emission direction, although it comprised so that it might become from the bottom in FIG. 5, you may arrange | position arbitrarily from top to bottom, the left to the right, etc.

Next, the internal configuration of the backlight block 4 of the backlight unit 3 of the backlight device of the present invention will be described with reference to FIG. 6A. FIG. 6A is a partial cross-sectional view of the backlight block 4 viewed from the X direction. 7 is an LED, 6 is an LED substrate on which the LED 7 is mounted, 610A is an LED cover surrounding the LED 7, 11 is a base chassis, 19 is a reflection sheet, 24 is an air layer, 22 and 23 are diffusion plates, and 620A is a support pin. Note that one to a plurality of LEDs 7 are mounted on the LED substrate 6.
6A, in the air layer 24, a plurality of LEDs 7 (for example, LED 7-1 in FIG. 5) are arranged at predetermined intervals along a predetermined direction (X direction in FIG. 5) via the LED substrate 6. It is attached to be. The LED 7 has a light emission direction parallel to the diffusion plate 22 from the air layer 24, that is, the optical axis of the light emitted from the LED 7 to the air layer 24 is the surface of the diffusion panel 22 (or the emission surface 403). It is provided so as to be parallel to the direction (Y direction) and perpendicular to the X axis.
The light emitted from the LED 7 travels through the air layer 24, is diffusely reflected between the reflection sheet 19 and the diffusion plate 22, is appropriately irradiated from the air layer 24 to the diffusion plate 22, and passes through the diffusion plate 23, the optical sheet 402, and the like. To the exit surface 403.
Here, the LED 7 is a side emission type (side view type) LED and emits white light.

In the configuration of FIG. 6A, the reflection sheet 19 is provided on the entire upper surface of the base chassis 11, the LED substrate 6 on which the LEDs 7 are mounted is provided on the upper surface side of the reflection sheet 19, and the LED cover 610A is It is provided on the LED substrate 6 so as to surround the LED 7. As a result, the LED substrate 6 and the LED cover 610 </ b> A are configured so that light does not leak from the other portions of the LED 7 except for the exit portion of the LED 7.
A support pin 620A is provided to keep the height of the air layer 24 between the base chassis 11 and the reflection sheet 19 and the diffusion plate 22 constant. However, the position of the support pin 620A is not limited to the position of the LED cover 610A or the rear part of the LED substrate 6 (lower side in the Y direction) as shown in FIG. 6A. In FIG. For convenience, they are only shown in individual positions.

As a result, light leaking directly above the LED 7 can be suppressed. Therefore, the luminance peaks (regions P1 and P2) described with reference to FIGS. 1 and 2 can be suppressed low, and a luminance distribution with little luminance unevenness can be realized.

6A, the optical sheet 420 is present on the upper surface (front side in the Z direction) of the diffusion plate 23 (in the case of a liquid crystal display device, the liquid crystal panel 1 is present). Not shown. One or more optical sheets 420 are stacked, and are, for example, brightness enhancement films such as BEF (Brightness Enhancement Film). Further, the positional relationship between the optical sheet 420 and the diffusion plate 23 may be arbitrary.

According to the first embodiment, the luminance distribution shown by the solid line in FIG. 1 can be corrected to achieve a luminance distribution that does not cause uneven luminance. Moreover, the light emitted from the LED can be emitted from the backlight device to the diffusion plate with less loss than in the past by the LED cover.
As a result, it is possible to realize a backlight device and a liquid crystal display device that can obtain high luminance with little luminance unevenness.

Next, Example 2 of the backlight device of the present invention will be described with reference to FIGS. 6B and 7. FIG. 6B is a partial cross-sectional view of the backlight block 4 viewed from the X direction, and FIG. 7 is a partial perspective view. 610B is an LED cover surrounding the LED 7, and 620B is a support pin.
FIG. 6B shows a configuration in which the instruction pin 620A between the base chassis 11 and the diffusion plate 22 in FIG. 6A is removed, and instead, a support pin 620B having a convex shape or the like is attached to the LED cover 610B.
The support pins 620 </ b> B cooperate with the LED cover 610 </ b> B and the LED substrate 6 to keep the height of the air layer 24 between the base chassis 11, the reflection sheet 19, and the diffusion plate 22 constant. Further, the support pins 620B are randomly arranged on the XY plane, and even when viewed from the emission surface 403 of the backlight device or the front surface side of the liquid crystal panel 1, there is a luminance boundary estimated to be generated due to the presence of the support pins 620B. It is preferable that it is not noticeable.

6B and 7, the optical sheet 420 is present on the upper surface (front side in the Z direction) of the diffusion plate 23 (in the case of a liquid crystal display device, the liquid crystal panel 1 is present). And it is not illustrated in FIG. As in the first embodiment, one or more optical sheets 420 are stacked, and are, for example, a brightness enhancement film such as BEF (Brightness Enhancement Film). Further, the positional relationship between the optical sheet 420 and the diffusion plate 23 may be arbitrary.

As a result, light leaking directly above the LED 7 can be suppressed, and further, a projection is provided on the LED cover to form a support pin, and the LED cover and the support pin have an integrated structure. One is reduced, and assembly is facilitated. Therefore, the alignment accuracy is improved, the luminance peaks (regions P1, P2) described with reference to FIGS. 1 and 2 can be suppressed low, and a luminance distribution with less luminance unevenness can be realized.

Next, Embodiment 3 of the backlight device of the present invention will be described with reference to FIGS. FIG. 8 is a partial cross-sectional view of the backlight block 4 viewed from the X direction, and FIG. 9 is a partial perspective view. Reference numeral 824 denotes a print pattern.
FIGS. 8 and 9 are the same as FIGS. 6B and 7 of the second embodiment, in which a printed pattern 824 is provided around the portion corresponding to the direction directly above the LED 7 (arrow 410 in FIG. 4) on the upper surface of the diffusion plate 22. It is.
The color of the print pattern 824 is, for example, white, but may be transparent. If the refractive index is different from that of the diffuser plate 22, it functions sufficiently. Further, the print pattern 824 is arranged so that the emission port of the LED 7 extends obliquely forward (upward in the Y direction) from directly above the LED 7 (upward in the Z direction). The shape is determined theoretically or experimentally, such as a rectangular shape, an elliptical shape, or a composite shape thereof. Further, it is not necessary to form the pattern by printing, and it is needless to say that a well-known technique may be used as the pattern forming method.

The printed pattern 824 reflects the incident light almost totally when light leaking directly above the LED 7 enters the diffusion plate 22. As a result, the light leaking directly above the LED 7 returns to the air layer 24. With this print pattern 824, in addition to the effects of the first and second embodiments, the luminance peaks (regions P1 and P2) described with reference to FIGS. 1 and 2 can be further suppressed, and the solid line L1 in FIG. The luminance distribution shown by the dotted line L2 in FIG. 1 can be obtained from the luminance distribution in FIG. Therefore, a luminance distribution with little luminance unevenness can be realized.

Next, Embodiment 4 of the backlight device of the present invention will be described with reference to FIGS. 10, 11 and 12. FIG. FIG. 10 is a partial cross-sectional view of the backlight block 4 viewed from the X direction, and FIG. 11 is a partial perspective view. Reference numeral 1010 denotes an LED cover.
10 and FIG. 11 are obtained by replacing the LED cover 610B with the LED cover 1010 in FIGS. 8 and 9 of the third embodiment.

The LED cover 1010 has an LED cover 610A of Example 1 and an LED 610B of Example 2 or Example 3 with an inclined surface at the rear (lower side in the Y direction) of the LED cover. Thus, for example, when the light emitted from the LED 7-1 in FIG. 5 reaches the next LED 7-2, the light is incident on the diffusion plate 22 obliquely when it is irradiated and reflected on the slope of the LED cover 1010. To do. As a result, the obliquely incident light is substantially totally reflected by the diffusion plate 22. Therefore, light leakage (for example, looks like a horizontal line) just above the rear portion of the LED 7 is reduced, and a luminance distribution with less luminance unevenness can be realized.

FIG. 12 is a partial perspective view of an embodiment of an LED cover used in the backlight device of the present invention, and shows a modification of the embodiment 4. In FIG. 12, the support pins 620B are not shown.
The LED cover 1210 in FIG. 12 has a curved surface at the rear of the LED cover. Other than the embodiment of FIG. 11 or FIG. 12, any surface shape may be used as long as the light irradiated on the rear surface is diffusely reflected and does not enter the surface of the diffusion plate 22 at a right angle. For example, fine irregularities may be provided on the rear surface.
In FIG. 12, one or a plurality of LEDs 7 mounted on the LED substrate 6 are provided in the storage portion 1201 partitioned by the partition 1202 of the LED cover 1210. The LED cover 1210 is, for example, a structure integrally formed for each backlight block 4 and is fixed to the base chassis 11 by screwing or the like at portions of mounting holes 1203 provided in various places.
According to the fourth embodiment, the luminance distribution shown by the solid line in FIG. 1 can be corrected to achieve a luminance distribution that does not cause uneven luminance. Moreover, the light emitted from the LED can be emitted from the backlight device to the diffusion plate with less loss than in the past by the LED cover.
As a result, it is possible to realize a backlight device and a liquid crystal display device that can obtain high luminance with little luminance unevenness.

Embodiment 5 of the backlight device of the present invention will be described with reference to FIGS. The LED cover 1010 in FIG. 13 is different from the LED cover 1210 in FIG. 12 described in the fourth embodiment in that a collar 1301 is provided in the vicinity of the upper surface of the emission port of each LED 7 of the LED cover 1310. FIG. 14 is a schematic diagram in which the LED cover 1310 according to the fifth embodiment is drawn on the simulation result diagram of the luminance distribution shown in FIG. FIG. 15 is a schematic diagram illustrating the LED cover 1210 according to the fourth embodiment shown in FIG. FIG. 16 shows the luminance distribution L4 improved by the fifth embodiment in addition to FIG.

As is apparent from FIG. 16 as compared with FIG. 15, by providing the eaves 1301 on the LED cover 1310, the amount of light traveling directly above the LED 7 is reflected by the amount of the first to fourth embodiments or more. Return to 24. For this reason, it is possible to suppress leakage to the diffusion plate 22 directly above (in the direction of the emission surface 403). As shown in FIG. 16, since the luminance distribution L1 is corrected to the luminance distribution L4, a backlight device and a liquid crystal display device with little luminance unevenness can be realized.
Note that the collar 1301 has a shape divided for each housing portion 1201 of the LED 7. The divided shapes are random shapes when viewed from the emission surface 403 or the front side of the liquid crystal panel 1, respectively, and also depending on the shape of the notch when viewed from the emission surface 403 of the backlight device or the front side of the liquid crystal panel 1. It is preferable that the luminance boundary estimated to be generated is not conspicuous.

As a result, according to the fifth embodiment, in addition to the effects of the first to fourth embodiments, the luminance distribution shown by the solid line in FIG. 1 can be corrected to achieve a luminance distribution with less luminance unevenness. Moreover, the LED cover and the print pattern allow light emitted from the LED to be emitted from the backlight device to the diffusion plate with less loss than in the past.

FIG. 17 is a side view of a sixth embodiment of the LED cover according to the present invention, and FIG. 18 is a perspective view of the sixth embodiment of the LED cover. Unlike the first to fifth embodiments described above, this embodiment removes the wall surface (hereinafter referred to as “rear wall surface”) of the LED cover that faces the rear and rear surfaces of the LED 7, and the upper surface side of the LED 7. It is constructed so as to cover only. Therefore, as shown in FIG. 16, the LED cover 1016 according to the present embodiment is substantially T-shaped when viewed from the side, and the base chassis 11, the reflection sheet 19, or the diffusion plate 22, above the LED 7, 23, a roof portion 1017 parallel to the surface 23, and an indicator portion 1018 attached to the LED substrate or base chassis 11 and supporting the roof portion 1017. A print pattern 824 similar to that of the above-described embodiment is formed at a position corresponding to the LED 7 of the roof portion 1017 and the front side thereof, and further support pins 620B are provided.
In the present embodiment, since the LED cover 1016 according to the present embodiment does not have a rear wall surface, the function of reflecting the light from the LED 7 on the rear wall surface is lost, and the amount of light to the front side of the LED 7 is reduced. However, in this embodiment, since the light from the LED located on the rear side of the LED at a certain position can be reduced by reflecting the light on the rear wall surface and going upward, when the diffusion plates 22 and 23 are viewed from above, Luminance unevenness such that the back of the LED cover 1016 shines locally is eliminated.
The width of the roof portion 1017 in this embodiment (dimension in the direction parallel to the light emission direction of the LED 7) is, as shown in the drawing, the longitudinal direction (LED 7) of the roof portion 1017 when viewed from the diffusion plates 22 and 23 side. (The direction of arrangement). However, the width of the portion corresponding to the LED 7 in the roof portion 1017 may be made larger than the width of the portion corresponding to the position between the LEDs 7. Further, the print pattern 824 is a continuous belt-like shape that is long in the longitudinal direction of the roof portion 1017 (the arrangement direction of the LEDs 7), but is not limited thereto, and is provided individually corresponding to the position of each LED 7. It may be oval or oval. Further, the elliptical or oval printed pattern 824 may further include a plurality of radial protrusions extending in the light emission direction of the LED 7.
As described above, according to the present embodiment, it is possible to realize a backlight device and a liquid crystal display device that can obtain high luminance with little luminance unevenness.

1: liquid crystal panel, 3: backlight unit, 4: backlight block, 6: LED substrate, 7: LED, 11: base chassis, 19: reflection sheet, 22, 23: diffuser plate, 24: air layer, 210: LED light emission direction, 300: video display device, 310: display unit, 320: stand, 402: optical sheet, 403: emission surface, 460: lower chassis, 610A, 610B, 1010, 1016, 1210, 1310: LED cover, 620A, 620B: support pin, 824: printing pattern, 1201: storage section, 1202: partition, 1203: hole, 1301, 1017: spear.

Claims (10)

In the backlight device for irradiating light from the exit surface,
The backlight device includes a base chassis, and a backlight unit including a plurality of backlight blocks on the base chassis.
Each of the backlight blocks is provided on the back side of the backlight block and on the base chassis, and is provided to face the reflection sheet. The light irradiation surface of the backlight from the reflection member In a direction parallel to the light irradiation surface of the backlight unit, disposed in a space between the diffuser plate and the reflection sheet, a plate-like diffusion plate arranged at a predetermined interval in a direction orthogonal to A plurality of LEDs (Light Emitting Diodes) that emit light, the LED mounted thereon, an LED substrate that is parallel to the reflective sheet, provided on the upper surface side of the reflective sheet, and attached to the LED substrate, the LED And an LED cover configured to cover the LED and the LED together with the LED substrate. 2. The backlight device according to claim 1, wherein the LED is a side view type LED. 2. The backlight device according to claim 1, wherein a projection for holding the base chassis and the diffusion plate at a predetermined distance is provided on the upper side in the Z direction of the LED cover. 4. The backlight device according to claim 3, wherein the LED cover and the protrusion are integrated. 2. The backlight device according to claim 1, wherein a pattern having a predetermined area for shielding light emitted above the LED is provided on the diffusion plate directly above the LED. 2. The backlight device according to claim 1, wherein a rear portion of the LED cover is an inclined surface. 2. The backlight device according to claim 1, wherein the LED cover is provided with a ridge above the LED in the Z direction and in the emission direction. 8. The backlight device according to claim 7, wherein the bag has a shape divided for each of the accommodating portions. In the backlight device for irradiating light from the exit surface,
The backlight device includes a base chassis, and a backlight unit including a plurality of backlight blocks on the base chassis.
Each of the backlight blocks is provided on the back side of the backlight block and on the base chassis, and is provided to face the reflection sheet. The light irradiation surface of the backlight from the reflection member In a direction parallel to the light irradiation surface of the backlight unit, disposed in a space between the diffuser plate and the reflection sheet, a plate-like diffusion plate arranged at a predetermined interval in a direction orthogonal to A plurality of LEDs (Light Emitting Diodes) that emit light, the LED mounted thereon, an LED substrate that is parallel to the reflective sheet, provided on the upper surface side of the reflective sheet, and attached to the LED substrate, the LED An LED cover that covers the upper side of the backlight device. A liquid crystal display device using a liquid crystal panel and the backlight device according to any one of claims 1 to 9.

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