JP2006330659A - Brace, and back light device and liquid crystal display device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the occurrence of uneven luminance caused by a brace while surely holding an optical structure like a diffusing plate. <P>SOLUTION: A brace 30 is provided in a back light device 140 or the like and supports an optical structure 141 on which direct light from a light source 21 or indirect light impinges, and a reflection angle control structure for controlling the quantity of light radiated from the circumferenceof of the brace 30 to the optical structure 141 is formed in a part of the brace 30. As the reflection angle control structure, for example, a reflection angle control member 31 which comprises a projection formed within a plane approximately parallel with an incidence face 141a of the optical structure 141 is provided on the surface of the brace 30, or a curved surface is formed in a top part of the brace 30. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a column that holds, for example, a space between a diffuser plate and a light source on which light from a light source is incident, a backlight device and a liquid crystal display device using the column.

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

In such a liquid crystal display device, a backlight system in which a color image is displayed by illuminating a transmissive liquid crystal display panel including a color filter with a backlight device that illuminates the surface from the back side becomes the mainstream. ing.
As a light source of the backlight device, a cold cathode fluorescent tube (CCFL) that emits white light using a fluorescent tube and a light emitting diode (LED) are promising.

  In particular, with the development of blue light emitting diodes, light emitting diodes that emit the three primary colors of light, red light, green light, and blue light, have been prepared, and the red light, green light, and blue light emitted from these light emitting diodes have been prepared. By mixing light, white light with high color purity can be obtained. Therefore, by using this light emitting diode as the light source of the backlight device, the color purity through the liquid crystal display panel is increased, so that the color reproduction range can be greatly expanded compared with the CCFL. Furthermore, the brightness of the backlight device can be significantly improved by using a high-output light-emitting diode chip (LED chip).

Using such a light emitting diode, for example, a direct type, that is, a backlight device in which the light emitting diode is arranged directly under the light emitting surface of the device has been proposed (for example, see Non-Patent Document 1).
Nikkei Electronics (Nikkei BP), December 20, 2004 (No. 889) pp. 123-130

  Incidentally, as described in Non-Patent Document 1, a backlight device for a liquid crystal display device requires a structure that supports an optical structure such as a diffusion plate. For example, the diffusion plate is generally made of resin and has a thickness of about 2 mm, although it varies depending on the size of the liquid crystal display panel, and does not have a structure that is rigid enough to maintain the plane itself. Therefore, a structure that supports the diffusion plate is required. For this structure, a column such as a cylinder or a cone is often used.

  FIG. 18 is a schematic cross-sectional view showing a general direct type backlight device. As shown in FIG. 18, a backlight device for a liquid crystal display device includes a frame (housing) 502, a reflection structure 520, a diffusion plate 541, and a column that holds the distance between the reflection structure 520 and the diffusion plate 541 constant. 530, which is composed of light emitting diodes 521R, 521G, and 521B of three colors of red, green, and blue arranged as light sources. The periphery of the diffuser plate 541 is supported by a frame 502 of the backlight device, and is supported by at least one column 530 near the center. Although not shown, a liquid crystal display panel is disposed on the diffusion plate 541. The three colors of light are mixed in a space formed between the reflective structure 520 and the diffuser plate 541, are emitted from the diffuser plate 541 as white light with uniform luminance, and enter the liquid crystal display panel.

  FIG. 19 shows the state of light at the end of the column. The light emitted from each of the light emitting diodes 521R, 521G, and 521B becomes light 550 having uniform luminance while being repeatedly reflected by the reflection structure of the peripheral portion. However, a certain proportion of the light 551 and 552 is reflected on the surface of the support column 530 and changes its angle toward the diffusion plate 541. In the vicinity of the region where the reflected light 551, 552 on the diffuser plate 541 is incident, in addition to the uniform light 550, the luminance increases by the amount of the reflected light 551, 552 reflected on the surface of the column 541, and the luminance A bright spot (bright area 562) is generated in the area 563 where the brightness is uniform, resulting in uneven brightness. In particular, as the backlight device becomes thinner due to the recent thinning of the liquid crystal display device, it is not possible to secure a sufficient optical path length until the light emitted from the light emitting diode enters the diffusion plate 541. Unevenness is likely to occur.

  Further, when the diameter of the support column is increased in order to increase the strength of the support column as a countermeasure against vibration, impact, etc. of the support column, as shown in FIG. Occurred, and the brightness was uneven. The shadow area 561 increases as the diameter of the column 530 increases.

  As one of the countermeasures for making the shadow inconspicuous, for example, it is conceivable to reduce the shadow, that is, to reduce the diameter of the support column, but this affects the strength of the support column. In recent years, the size of liquid crystal display devices has been increasing, and the larger the liquid crystal display panel, the larger the diameter of the columns 530 and the number of the columns 530 needing to be increased. The effect of uneven brightness cannot be ignored.

  On the other hand, a backlight device for a liquid crystal display uses a colorless and transparent resin substrate called a diverter plate (hereinafter also referred to as “light transmissive substrate”) between a diffusion plate and a light emitting diode. is there.

  An example of a liquid crystal display device in which a light-transmitting substrate is used between the diffusion plate and the light emitting diode is shown in FIG. FIG. 20 is a schematic sectional view of the liquid crystal display device. A light-transmitting substrate 560 with a pattern is disposed above the light emitting diodes 521R, 521G, and 521B. The light transmissive substrate 560 reflects and diffuses unnecessary light leaking right above the light emitting diodes by dots 561 printed in a predetermined pattern. The diffuser plate 541 and the light-transmitting substrate 560 are supported by columns 530 and 570, respectively. A similar configuration is also described in Non-Patent Document 1.

  The distance between the light-transmitting substrate 560 and the light-emitting diodes 521R, 521G, and 521B is as small as about 1 mm due to restrictions on optical characteristics even when the display surface size is 40 to 46 inches, for example. 560 may contact the light emitting diodes 521R, 521G, and 521B, and the light emitting diode may be damaged.

  FIG. 21 shows an example of a state in which the light-transmitting substrate is deformed. When the distance between the support columns 570 supporting the light transmissive substrate 560 is, for example, about 60 mm, when vibration or impact is applied, the light transmissive substrate 560 bends and deforms by about 1 mm in the vertical direction.

  There is no problem with the deformation 560T in the direction away from the light emitting diode, but the deformation 560U in the direction closer to the light emitting diode may come into contact with the light emitting diode and the light emitting diode may be damaged.

  As a countermeasure, it is conceivable to increase the distance between the light-transmitting substrate and the light-emitting diode or increase the number of support columns that support the light-transmitting substrate.

  First, when the distance is increased, among the light emitted from the light emitting diodes 521R, 521G, and 521B in the directly upward direction, the component directly irradiated on the diffusion plate 541 without being irradiated on the dots 561 of the light-transmitting substrate 560 increases. The optical properties are adversely affected.

  Further, if the distance between the columns 570 is small, for example, 30 mm, which is half, the amount of deformation of the light-transmitting substrate 560 is also halved, but the number of columns 570 increases more than twice. Since both the light-transmitting substrate 560 and the column 570 are made of resin, the number of places where dust (dust, powder) generated when the tip of the column 570 comes into contact with the light-transmitting substrate 560 and rubs increases. As a result, the generation of dust increases, which is one of the causes of uneven brightness and uneven color.

The present invention has been made in view of such a point, and a first object is to suppress the occurrence of uneven brightness due to the support column while reliably holding an optical structure such as a diffusion plate.
The second object is to prevent the light-emitting diode from being damaged due to contact between the light-transmitting substrate and a light source such as a light-emitting diode.

In order to solve the above-mentioned problems, the present invention provides a support column for supporting an optical structure provided in a backlight device or the like to which direct light and indirect light from a light source are incident. The reflection angle control structure for controlling the amount of light irradiated to the optical structure is formed.
As the reflection angle control structure, for example, a reflection angle control member including a convex portion formed on a surface of a support column in a plane substantially parallel to the incident surface of the optical structure is provided.
Or it is set as the structure which formed the curved surface in the top part of the support | pillar.

According to the above configuration, when the reflection angle control member is provided as the reflection angle control structure, the light reflected by the column surface is reflected by the reflection angle control member and returned again to the mixing space, so that the optical path length of the light is increased. be able to. As a result, it is mixed again and becomes uniform light, which is incident on the optical structure. In addition, it is possible to block the irradiation of light on the top of the head so that the light irradiated on the top of the support column is reflected and does not go in the upward direction. Therefore, it is possible to prevent uneven brightness on the diffuser plate that is generated by light reflected from the surface or the top of the column.
In addition, when a curved surface is formed at the top of the column as the reflection angle control structure, the amount of light directed in the upward direction can be controlled by changing the shape, that is, the radius of curvature of the curved surface, and changing the angle at the top. Therefore, uneven brightness can be suppressed.

  Further, the backlight device of the present invention is a backlight device having a support for supporting an optical structure on which direct light and indirect light from a light source are incident. A reflection angle control structure for controlling the amount of light applied to the light source is formed.

  According to the above configuration, it is possible to control the amount of light just above the column that is emitted to the optical structure such as the diffusion plate disposed above the column, and to appropriately adjust the brightness of the surface of the optical structure. it can.

  In the backlight device of the present invention, a light-transmitting substrate is disposed between the optical structure on which light from a plurality of light sources is incident and the plurality of light sources, approximately parallel to the optical structure. The backlight device according to the present invention is characterized in that a first support column that supports the light-transmitting substrate and a second support column that is lower than the first support column and higher than the plurality of light sources are provided.

  According to the above configuration, it is possible to prevent the light transmissive substrate and the light source from coming into contact with the second column without increasing the number of columns supporting the light transmissive substrate.

  In the backlight device of the present invention, a light-transmitting substrate is disposed between the optical structure on which light from a plurality of light sources is incident and the plurality of light sources, approximately parallel to the optical structure. In the backlight device, a first support column that supports the optical structure and the light-transmitting substrate by the first locking portion and the second locking portion, respectively, and lower than the light-transmitting substrate supported by the first column. And a second support column higher than the plurality of light sources is provided.

  According to the above configuration, it is possible to prevent the light transmissive substrate and the light source from coming into contact with the second column without increasing the number of columns supporting the light transmissive substrate. Furthermore, since the column supporting the optical structure above the light transmissive substrate and the column supporting the light transmissive substrate are integrated, the number of columns of the entire backlight device can be reduced.

  Further, the liquid crystal display device of the present invention is a liquid crystal display device comprising: a transmissive liquid crystal display panel; and a backlight device that includes a plurality of light sources and illuminates the liquid crystal display panel from the back side. Has a support that supports an optical structure to which direct light and indirect light from a light source are incident, and a reflection that controls the amount of light emitted from the periphery of the support to the optical structure is provided on a part of the support. An angle control structure is formed.

  According to the above configuration, it is possible to control the amount of light directly above the support post emitted to the optical structure such as a diffusion plate disposed above the backlight device, and to appropriately adjust the brightness of the surface of the optical structure. can do. Therefore, the luminance unevenness and color unevenness of the liquid crystal display panel are reduced.

  As described above, according to the present invention, for example, an optical structure such as a diffusing plate of a backlight device can be securely held by a support, and the occurrence of uneven brightness due to the support can be suppressed. Therefore, when this backlight device is used in a liquid crystal display device, luminance unevenness and color unevenness are suppressed and quality is improved.

  Further, the back light device is configured to include at least a support column that supports the light-transmitting substrate and auxiliary columns that are lower than the support column and higher than the plurality of light sources, thereby supporting the light-transmitting substrate. Without increasing the number (the cause of dust generation), it is possible to prevent the light source from being damaged due to the collision between the light transmissive substrate and the light source. In addition, since the number of support columns that support the light-transmitting substrate is reduced, the generation of dust is reduced, and the brightness and color unevenness of the liquid crystal display device are suppressed and the quality is improved.

Examples of the best mode for carrying out the present invention will be described below, but the present invention is not limited to the following examples.
The present invention can be applied to, for example, a transmissive color liquid crystal display device 100 configured as shown in FIG. The transmissive color liquid crystal display device 100 includes a transmissive color liquid crystal display panel 110 and a backlight device 140 provided on the back side of the color liquid crystal display panel 110. Although not shown, the transmissive color liquid crystal display device 100 includes a receiving unit such as an analog tuner and a digital tuner that receives terrestrial and satellite waves, and a video signal that processes a video signal and an audio signal received by the receiving unit, respectively. An audio signal output unit such as a processing unit, an audio signal processing unit, a speaker that outputs an audio signal processed by the audio signal processing unit, and the like may be provided.

  In the transmissive color liquid crystal display panel 110, two transparent substrates (TFT substrate 111 and counter electrode substrate 112) made of glass or the like are arranged to face each other, and, for example, twisted nematic (TN) liquid crystal is provided in the gap. The liquid crystal layer 113 encapsulating the liquid crystal layer 113 is provided. On the TFT substrate 111, signal lines 114 arranged in a matrix, scanning lines 115, thin film transistors 116 serving as switching elements arranged at intersections of the signal lines 114 and the scanning lines 115, and pixel electrodes 117 are formed. Has been. The thin film transistor 116 is sequentially selected by the scanning line 115 and writes the video signal supplied from the signal line 114 to the corresponding pixel electrode 117. On the other hand, a counter electrode 118 and a color filter 119 are formed on the inner surface of the counter electrode substrate 112.

  The color filter 119 is divided into a plurality of segments corresponding to each pixel. For example, as shown in FIG. 2, it is divided into three segments of a red filter CFR, a green filter CFG, and a blue filter CFB which are three primary colors. The arrangement pattern of the color filter 119 includes a delta arrangement and a square arrangement, although not shown, in addition to the stripe arrangement shown in FIG.

The configuration of the transmissive color liquid crystal display device 100 will be described again with reference to FIG. In the transmissive color liquid crystal display device 100, the transmissive color liquid crystal display panel 110 having such a configuration is sandwiched between two polarizing plates 131 and 132, and white light is irradiated from the back side by the backlight device 140. By driving with an active matrix system, a desired full-color image can be displayed.
The backlight device 140 illuminates the color liquid crystal display panel 110 from the back side. As shown in FIG. 1, the backlight device 140 includes a diffusion plate 141 and a diffusion plate in a backlight case 120 in order to mix light emitted from the light source and light emitted from the light source into white light. An optical function sheet group 145 such as a diffusion sheet 142, a prism sheet 143, and a polarization conversion sheet 144 that are arranged on the plate 141 is provided.
The diffusing plate 141 makes the luminance emitted from the surface emission uniform by internally diffusing the light emitted from the backlight housing 120.

  In general, the optical function sheet group has, for example, a function of decomposing incident light into orthogonal polarization components, a function of compensating for a phase difference of light waves to achieve a wide-angle viewing angle and preventing coloring, a function of diffusing incident light, and a brightness improvement And is provided to convert the light emitted from the backlight device 140 into illumination light having optical characteristics optimal for illumination of the color liquid crystal display panel 110. . Therefore, the configuration of the optical function sheet group 145 is not limited to the diffusion sheet 142, the prism sheet 143, and the polarization conversion sheet 144 described above, and various optical function sheets can be used.

FIG. 3 shows a schematic configuration diagram in the backlight housing 120. As shown in FIG. 3, the backlight housing 120 uses a red light emitting diode 21R that emits red light, a green light emitting diode 21G that emits green light, and a blue light emitting diode 21B that emits blue light as light sources. Yes.
For example, the peak wavelengths of red light emitted from the red light emitting diode 21R, green light emitted from the green light emitting diode 21G, and blue light emitted from the blue light emitting diode 21B are about 640 nm, 530 nm, and 450 nm, respectively. The peak wavelengths of red light and blue light emitted by the red light emitting diode 21R and the blue light emitting diode 21B may be shifted from 640 nm to the long wavelength side and from 450 nm to the short wavelength side, respectively. In this way, when the peak wavelength is shifted to the long wavelength side and the short wavelength side, the color gamut can be expanded, so that the color reproduction range of the image displayed on the color liquid crystal display panel can be expanded.
In the following description, when the red light emitting diode 21R, the green light emitting diode 21G, and the blue light emitting diode 21B are collectively referred to, they are simply referred to as the light emitting diode 21.

  The light emitting diode 21 has the highest luminance of the light emitted in the upward direction, that is, the emitted light component emitted in the direction perpendicular to the incident surface, as generally used, and in the vertical direction (in this example, the diffusion plate 141). As the angle increases with respect to the normal direction), a light-emitting diode having a radiation directivity characteristic in which the luminance of the emitted light component decreases is used. Alternatively, a side-emitting type having a lens function that mainly emits light in the lateral direction, such as the lens-shaped LED chip described in Non-Patent Document 1, is used.

As shown in FIG. 3, a plurality of the light emitting diodes 21 are arranged in a row in a desired order on the wiring board 22, thereby forming a light emitting diode unit 21n (n is a natural number). Each wiring board 22 is connected to a driving driver board (not shown).
In order to form the light emitting diode unit 21n, the order in which the light emitting diodes 21 are arranged on the wiring board 22 is a red light emitting diode 21R, a green light emitting diode 21G, and a blue light emitting diode 21B as shown in FIG. Although the most basic arrangement method or not shown, for example, the green light emitting diodes 21G are arranged at equal intervals, and the red light emitting diodes 21R and the blue light emitting diodes 21B are alternately arranged between the adjacent green light emitting diodes 21G. There are various arrangement methods such as order.
The arrangement of the light emitting diode units 21n in the backlight housing 120 may be arranged so that the longitudinal direction of the light emitting diode units 21n is in the horizontal direction, as shown in FIG. The light emitting diode units 21n may be arranged so that the longitudinal direction thereof is the vertical direction, or both may be combined. Or it can also be set as the arrangement | positioning which does not form the light emitting diode unit by which the light emitting diode of each color is uniformly arrange | positioned by a predetermined law, and the light emitting diode is arranged in multiple rows.

The method of arranging the light emitting diode units 21n so that the longitudinal direction is the horizontal direction or the vertical direction is the same as the CCFL arrangement method used as the light source of the conventional backlight device. The designed design know-how can be used, and the cost and time required for manufacturing can be shortened.
The inner wall surface 120a of the backlight housing 120 is a reflective surface that has been subjected to reflection processing in order to increase the utilization efficiency of the light emitted from the light emitting diode 21.

  4 shows a part of a schematic cross-sectional view along the line XX attached to the transmissive color liquid crystal display device 100 shown in FIG. 1 when the transmissive color liquid crystal display device 100 is assembled. As shown in FIG. 4, a color liquid crystal display panel 110 constituting the liquid crystal display device 100 includes spacers 103 a and 103 b formed by an external frame 101 that is an external housing of the transmissive color liquid crystal display device 100 and an internal frame 102. It is hold | maintained so that it may pinch | interpose through. A guide member 104 is provided between the outer frame 101 and the inner frame 102, and the color liquid crystal display panel 110 sandwiched between the outer frame 101 and the inner frame 102 is displaced in the longitudinal direction. Is suppressed.

On the other hand, the backlight device 140 constituting the transmissive color liquid crystal display device 100 includes the diffusion plate 141 on which the optical function sheet group 145 is laminated as described above. Further, a reflection sheet 126 is disposed between the diffusion plate 141 and the backlight housing 120.
The reflection sheet 126 is disposed so that the reflection surface thereof faces the light incident surface 141 a of the diffusion plate 141 and is closer to the backlight housing 120 than the light emitting direction of the light emitting diode 21. As the reflection sheet 126, for example, a silver-enhanced reflection film formed by sequentially laminating a silver reflection film, a low refractive index film, and a high refractive index film on a sheet base material can be used. In addition, the reflection sheet 126 is mainly emitted from the light emitting diode 21 and radiated downward due to the radiation angle distribution thereof, or the inner wall surface 120a which is subjected to reflection processing of the backlight housing 120 and is used as a reflection surface. Reflects reflected light. The reflection sheet may be diffused.

  The diffusion plate 141 is held by a bracket member 108 provided in the backlight housing 120 and supported by a support column 30 on which the reflection angle control structure of the present invention is formed. The support column 30 is provided with a reflection angle control structure such as a reflection angle control member 31 on the support column so that the light reflected from the support column surface does not go to the diffusion plate as it is or enters the diffusion plate 141 at a shallow incident angle. ing. The column having the configuration of the present invention will be described in detail later.

  In addition, the fixing method of the support | pillar 30 forms a female screw (tap) in the bottom face of the support | pillar 30, for example, pinches | interposes the reflective sheet 126, and fixes it with a male screw (bolt). Alternatively, the bottom surface of the support column 30 may be bonded and fixed to the reflection sheet 126. Alternatively, as described in Non-Patent Document 1, the tip portion extending downward from the bottom surface of the support column may have an irreversible structure and may be fixed so as not to come out after being fitted into the hole provided in the reflection sheet 126.

  Above the light emitting diode 21, a light-transmitting substrate (so-called diverter plate) 60 made of a colorless and transparent resin and having a pattern is disposed substantially parallel to the diffusion plate 141. The light-transmitting substrate 60 reflects and diffuses unnecessary light that leaks from the light emitting diodes 21 directly upward and causes a so-called hot spot by the dots 61 printed in a predetermined pattern.

  The light transmissive substrate 60 is supported by a plurality of resin posts 70 while maintaining a predetermined appropriate distance from each light emitting diode 21. For example, when the liquid crystal display surface is about 40 to 46, an appropriate value of the distance A between the light emitting diode 21 and the package is about 1 mm. When the distance A is about 1 mm, the optical characteristics of the dots 61 are the best. The thickness of the dot 61 is almost negligible.

  Further, a plurality of resin posts 71 are provided. The struts 70 are in direct contact with the light-transmitting substrate 60 and cause the resin to rub and generate dust (powder, dust). Therefore, in order to prevent contact between the light-transmitting substrate 60 and the package of the light emitting diode 21, a support 71 is provided as an auxiliary. The height of the support 71 is lower than the support 70 by the distance B, but is higher than the package of the light emitting diode 21. For example, it is assumed to be about 0.5 mm lower than the column 70.

  In this example, two types of support column heights related to the light-transmitting substrate 60 are prepared, one is a column 70 that holds the height of the light-transmitting substrate 60, and the other is the height. The column 71 is lower than the former column 70 and has a height closer to the light-transmitting substrate 60 than the light emitting diode 21. As a result, the column 71 does not normally contact the light transmissive substrate 60, but when the light transmissive substrate 60 is deformed due to vibration or impact, the light transmissive substrate 60 is received before the light emitting diode 21. Damage to the light emitting diode 21 can be prevented.

  The transmissive color liquid crystal display device 100 having such a configuration is driven by a drive circuit 200 as shown in FIG. 5, for example. The driving circuit 200 includes a color liquid crystal display panel 110, a power source 210 that supplies driving power for the backlight device 140, an X driver circuit 220 and a Y driver circuit 230 that drive the color liquid crystal display panel 110, and video signals supplied from the outside. Or an RGB process processing unit 250 that receives a video signal received by a receiving unit (not shown) included in the transmissive color liquid crystal display device 100 and processed by the video signal processing unit, via an input terminal 240, and the RGB process. An image memory 260 and a control unit 270 connected to the processing unit 250, a backlight drive control unit 280 for driving and controlling the backlight device 140, and the like are provided.

In the drive circuit 200, the video signal input through the input terminal 240 is subjected to signal processing such as chroma processing by the RGB process processing unit 250, and is further suitable for driving the color liquid crystal display panel 110 from the composite signal. It is converted into an RGB separate signal and supplied to the control unit 270 and also supplied to the X driver 220 via the image memory 260.
Further, the control unit 270 controls the X driver circuit 220 and the Y driver circuit 230 at a predetermined timing according to the RGB separate signal, and supplies the X driver circuit 220 together with the video signal from the image memory 260. By driving the color liquid crystal display panel 110 with the RGB separate signal, an image corresponding to the RGB separate signal is displayed.

  The backlight drive control unit 280 generates a pulse width modulation (PWM) signal from the voltage supplied from the power supply 210 and drives each light emitting diode 21 that is a light source of the backlight device 140. In general, the color temperature of a light emitting diode has a characteristic that it depends on an operating current. Therefore, in order to reproduce the color faithfully (with a constant color temperature) while obtaining a desired luminance, it is necessary to drive the light emitting diode 21 using a pulse width modulation signal to suppress the color change.

The user interface 300 selects a channel to be received by the above-described receiving unit (not shown), adjusts an audio output amount to be output by an audio output unit (not shown), or from the backlight device 140 that illuminates the color liquid crystal display panel 110. This is an interface for executing white light brightness adjustment, white balance adjustment, and the like.
For example, when the user adjusts the brightness from the user interface 300, the brightness control signal is transmitted to the backlight drive control unit 280 via the control unit 270 of the drive circuit 200. In response to the luminance control signal, the backlight drive control unit 280 changes the duty ratio of the pulse width modulation signal for each of the red light emitting diode 21R, the green light emitting diode 21G, and the blue light emitting diode 21B to change the red light emitting diode 21R, green The light emitting diode 21G and the blue light emitting diode 21B are driven and controlled.

  Next, in the backlight device and the liquid crystal display device of the present invention, the schematic configuration of each example of the support will be described.

(1) First Embodiment FIGS. 6A and 6B show a column according to an embodiment of the present invention, in which A is a side view and B is a top view. The support column 30 has a substantially conical shape having a curved surface at the top 30a of the tip. In this example, for example, a substantially flange-like shape (substantially extending over the entire circumference) for reflecting light reflected by the column surface (conical surface) to a part of the column 30 and returning it to the light mixing space between the light source and the diffusion plate. An umbrella-shaped reflection angle control member 31 is formed. The reflection angle control member 31 of the present example has a substantially disk shape or a substantially donut shape with convex portions provided in a plane substantially parallel to the diffuser plate 141 on the conical surface. As shown in FIG. 6B, the diameter of the reflection angle control member 31 having a substantially disk shape is preferably larger than the bottom surface diameter of the support column 30. Further, if the parietal portion 30a is a plane parallel to the diffuser plate 141, that is, a flat surface, the luminance at the upper portion of the parietal portion 30a on the surface of the diffuser plate 141 is insufficient and uneven luminance occurs. The structure has a moderately curved surface.

In this example, the support column 30 and the reflection angle control member 31 are formed by injection molding using an ABS resin (Acrylonitrile Butadiene Styrene polymer), which is a diffusely reflective material. Various modes are conceivable using this. For example, the reflection angle control member 31 may be integrated with the support 30 or may be a separate structure in which the reflection angle control member 31 is assembled and fixed after the support 30 is formed. In the case of separate structures, the same material or different materials may be used.
The column 30 may be a cylindrical shape, but in consideration of the luminance distribution above the column, a shape in which the portion in contact with the diffusion plate 141 is narrow, that is, a cone, particularly a right cone is more preferable. The shape is not necessarily limited to a conical shape or a cylindrical shape, and may be a quadrangular weight or a rectangular parallelepiped.

  FIG. 7 shows a side view of the support column 30 when the reflection angle control member 31 is provided at a low position. The installation position (h1 / h2 ratio) and diameter of the reflection angle control member 31 are determined based on the incident angle θ of the chief ray emitted from the light source to the diffusion plate 141 and the like. Although depending on the diameter of the reflection angle control member 31, it is installed with a tendency that h1 is large when the incident angle θ is large and h1 is small when the incident angle θ is small.

Here, the relationship between the incident angle of the principal ray and the position of the reflection angle control member 31 will be described in more detail.
When the incident angle of the chief ray is large, the reflection angle control member 31 is set at a high position of the column 30 as shown in FIG. For example, when the incident angle of the chief ray with respect to the diffuser plate 141 is large as in the case of a side emission type light emitting diode, the light 152a that is not directly irradiated onto the top 30a is directly incident on the diffuser 141, but comes toward the top 30a. The light 152b is reflected by the reflection angle control member 31, and is prevented from being reflected in the upward direction by the crown 30a.
Further, the light 151 that is reflected by the surface (conical surface) of the support column 30 and goes directly upward is reflected by the reflection angle control member 31. The reflected light is diffusely reflected by the reflection sheet 126 and mixed again. The light reflected by the reflection angle control member 31 and returned to the mixing space has a longer optical path length, so that the luminance is uniform with other light. Thereafter, the light is incident on the diffusion plate 141 as light having a uniform luminance.

On the other hand, when the incident angle of the chief ray is small, the reflection angle control member 31 is set at a low position of the column 30 as shown in FIG. For example, when the incident angle of the principal ray with respect to the diffusion plate 141 is small, such as when using a light emitting diode having a radiation directivity characteristic that the luminance of the outgoing light component emitted in the vertical direction is the highest, direct irradiation to the top 30a. The light 153a that is not applied is directly incident on the diffuser plate 141, but the light 153b that is directed toward the top 30a is reflected by the reflection angle control member 31 at a low position, thereby preventing the head 30a from being reflected directly upward.
Further, the light 152 reflected on the surface (conical surface) of the support column 30 and directed upward is reflected by the reflection angle control member 31, diffusely reflected by the reflection sheet 126, mixed again, and then incident on the diffusion plate 141 as described above. Is done.

  As described above, the attachment position and the diameter of the reflection angle control member 31 are determined by the relationship between the incident angle θ of the light emitted to the vicinity of the top 30a of the support column 30 and the light applied to the surface of the support column 30. .

According to the above-described embodiment, since the reflection angle control member is provided on the support column, the light reflected by the support column surface is reflected by the reflection angle control member and returned to the mixing space again, so that the optical path length of the light is increased. can do. Then, the light reflected by the reflection angle control member is mixed again and then becomes uniform light and is emitted from the diffusion plate. Moreover, the light irradiation to the top of the head can be blocked so that the light reflected from the top of the support column does not go in the upward direction.
Accordingly, it is possible to prevent uneven brightness on the diffusion plate that is generated by light reflected from the surface of the support column or from the top of the head.

(Second Embodiment)
FIG. 10 shows a column according to the second embodiment of the present invention, in which A is a side view and B is a top view. The reflection angle control member 32 of the present example has a configuration in which the shape of the reflection angle control member 31 in the first embodiment is changed from a disk shape (see FIGS. 6A and 6B) to an elliptical shape (see FIG. 10B). ).
The distance between the light sources of the backlight device is not necessarily arranged to be uniform. For example, in the case of the example of FIG. 3, the distance between adjacent light emitting diodes on the same light emitting diode unit is small. However, even among the closest light emitting diodes between different light emitting diode units, the distance is larger than that between adjacent light emitting diodes on the same light emitting diode unit. In this case, in the vicinity of the support column 30 on the surface of the diffusion plate 141, variations in individual light emitting diodes may be added, and the luminance distribution on the surface of the diffusion plate 141 above the top 30a may not be a clean circle. In that case, the reflection angle control member 32 is made into an ellipse or other appropriate shape according to the luminance distribution.

(Third embodiment)
FIG. 11 is a side view of a column according to the third embodiment of the present invention. In this example, an inclined surface 31 b is provided so that the peripheral edge 31 a of the reflection angle control member 31 in the first embodiment is inclined with respect to the incident surface of the diffusion plate 141 and faces the light emitting diode 21. When the peripheral edge 31a of the reflection angle control member 31 is substantially perpendicular to the incident surface of the diffusing plate 141, the light reflected by the peripheral edge 31a is directed directly upward, which is one cause of luminance unevenness. Due to the structure of the inclined surface 31b of this example, the light reflected by the inclined surface 31b returns to the mixing space again and is mixed with other light, so that uneven brightness can be prevented.

(Fourth embodiment)
FIG. 12 shows a column according to the fourth embodiment of the present invention, in which A is a side view and B is a top view. In this example, a curved surface portion is formed in the top 41 of the conical column 40 as a reflection angle control structure, and the amount of light directed in the upward direction is controlled by changing the angle at the top by the shape of the curved surface, It eliminates uneven brightness. Specifically, the curvature radius (R) of the top 41 is made larger than the top of the support in the first to third embodiments. The column 40 is preferably made of a material having irregular reflection or diffuse reflection such as ABS resin.

  First, FIG. 13 shows an example in which the curvature radius at the top of the column is small. In this example, when the diameter of the pillar top 41a is 2 mm, the radius of curvature is about 1.0 mm. In this case, the amount of the light 154 whose angle changes due to the curved surface portion of the top portion 41a is large, and as a result, the region 51 that becomes brighter becomes wider.

  Next, an example in the case where the curvature radius of the top of the column is large is shown in FIG. In this example, when the diameter of the column top portion 41b is φ2 mm, the radius of curvature is about 2.0 mm. In this case, the amount of the light 155 whose angle changes due to the curved surface portion of the top portion 41b is small, and as a result, the brightened region 51 becomes small.

  As described above, it is possible to control the amount of light that is changed in angle at the top of the head by the shape of the curved portion of the top of the support column and is directed directly upward, so that uneven brightness can be suppressed. This fourth embodiment is easy to manufacture because no reflection angle control member is provided, and in particular, the light source mainly emits light in the lateral direction as described in Non-Patent Document 1 described above. This is suitable when using a side emitting type having a radiating lens function.

  FIG. 15 shows luminance distribution characteristics on the surface of the diffusion plate by the support of each of the above-described embodiments. The horizontal axis represents the distance (mm) from the support center axis, and the vertical axis represents the luminance (cd / m2; nit). In this figure, when the radius of curvature (R) of the top of the column of FIG. 13 is small, when the radius of curvature (R) of the top of the column of FIG. 14 is large, and with the reflection angle control member of FIG. The measurement results are shown for. From this brightness distribution characteristic, when the curvature radius of the top of the head is small, the amount of light is large around the center axis of the support column, but when the curvature radius of the top of the head is large, the amount of light is reduced. It can be seen that the luminance distribution is uniform. Further, when there is a reflection angle control member, the luminance above the support column is suppressed, and the conventional bright region (see FIG. 19) can be eliminated. Here, a drop in luminance is observed in the vicinity of the center axis of the support column, but it can be corrected by appropriately changing the installation position and diameter of the reflection angle control member.

  According to the above-described embodiment, by adjusting the curvature radius of the curved surface portion (reflection angle control structure) of the column head top portion, the amount of light reflected by the curved surface portion of the column head top portion and directed upward of the column head is controlled. Brightness unevenness can be eliminated.

(Fifth embodiment)
FIG. 16: shows the side view of the support | pillar which concerns on the 5th example of embodiment of this invention. This example is a combination of the third embodiment and the fourth embodiment described above. The columnar structure has a reflection angle control structure in which the curvature radius of the head top portion 41 is increased and the reflection angle control member 31 is formed at an appropriate position on the conical surface.
With such a structure, the synergistic effect of the third embodiment example and the fourth embodiment example can be obtained. For example, light reflected from the column surface and light having a small incident angle toward the crown 41 are reflected by the reflection angle control member 31 to the mixing space, and light directly incident on the crown 41 is directly above. The reflected light in the direction can be reduced. Therefore, uneven brightness can be suppressed.

  As described above, when the support of the above structure is applied to a backlight device such as a liquid crystal display device, the optical structure such as the diffusion plate is securely held by the support and the occurrence of uneven brightness due to this support is suppressed. Can do. Therefore, the luminance unevenness and color unevenness of the liquid crystal display device are suppressed, and the image quality and quality are improved.

  Here, another embodiment of the column supporting the light-transmitting substrate 60 will be described.

  FIG. 17 is a schematic cross-sectional view of an example of a liquid crystal display device. 17 is different from the example of FIG. 4 in that the support column 30 for supporting the diffusion plate 141 and the support column 70 for supporting the light-transmitting substrate 60 are integrated.

  As shown in FIG. 17, the support column 80 in which the support function for the diffusion plate 141 and the support function for the light-transmitting substrate 60 are integrated, has a tip portion 83 extending downward from the bottom of the support column 80 with an irreversible structure. And the 1st latching | locking part 81 of the support | pillar 80 is inserted and fixed in the hole provided in the translucent base | substrate 60. FIG. Further, the second locking portion 82 of the support 80 is fitted and fixed in a hole provided in the reflection sheet 126. With such a structure, the support column 80 erected once is maintained without being removed even if vibration or impact is applied.

  The distance between the diffusing plate 141 and the light transmissive substrate 60 is determined by the distance H1 between the apex of the support column 80 and the first locking portion 81. Further, the distance between the light transmissive substrate 60 and the light emitting diode 21 is determined by the distance H <b> 2 between the first locking portion 81 and the second locking portion 82 of the support column 80.

  4, the height of the support 71 is lower than the distance H2 between the light transmitting base 60, that is, the first locking portion 81 and the second locking portion 82, and higher than the package of the light emitting diode 21. To do.

  In this example, since the column supporting the diffusion plate 141 and the column supporting the light-transmitting substrate 60 are integrally configured, in addition to the operational effects of the column 70 and the column 71 shown in FIG. The total number can be reduced.

  In addition, the support | pillar of this invention is used for the thing for which the support | pillar was united and integrated with the light emitting diode, the thing which used the light emitting diode itself as a support | pillar by thinning of a backlight apparatus, etc., or the wiring use in a backlight apparatus. The present invention is also applied to a case where a function as a support is given to various other structures such as a structure that is also used as a support.

  In the above-described embodiments, the direct type backlight device is described as an example. However, the structure of the present invention is also applied to a side edge type backlight device or a backlight device of these types using a CCFL. Can be used.

  Furthermore, the present invention is not limited to each of the above-described embodiments. For example, the present invention can be applied to a backlight device that does not use a light-transmitting substrate, a reflection angle control member mounting position, and a curvature radius of the top of the head. Of course, various modifications and changes can be made without departing from the scope of the present invention, such as the material.

1 is a schematic exploded perspective view of an example of a liquid crystal display device shown as the best mode for carrying out the present invention. 1 is a schematic plan configuration diagram of an example of a color filter of a liquid crystal display panel according to a liquid crystal display device shown as the best mode for carrying out the present invention. 1 is a schematic perspective view of a backlight device according to a liquid crystal display device shown as the best mode for carrying out the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional configuration diagram (part 1) of an example of a liquid crystal display device shown as the best mode for carrying out the present invention. 1 is a schematic block configuration diagram of an example of a drive circuit for driving a liquid crystal display device shown as the best mode for carrying out the present invention. A is a side view of a support according to the first embodiment of the present invention, and B is a top view thereof. It is a figure which shows the example of the support | pillar which has a reflection angle control member in the low position in the 1st example of an embodiment of this invention. It is a figure with which it uses for description when the incident angle of a chief ray is large in the 1st Example of this invention. It is a figure with which it uses for description in case the incident angle of a chief ray is small in the 1st Example of this invention. A is a side view of a support according to a second embodiment of the present invention, and B is a top view of the same. It is a side view of the support | pillar which concerns on the 3rd Example of this invention. A is a side view of a column according to a fourth embodiment of the present invention, and B is a top view thereof. It is a figure where it uses for description when the curvature radius of the support | pillar tip is small in the 4th example of an embodiment of the present invention. It is a figure where it uses for description when the curvature radius of the support | pillar front-end | tip is large in the 5th Example of this invention. It is a luminance distribution characteristic view of each embodiment example of the support according to the present invention. It is a side view of the support | pillar which concerns on the 5th example of embodiment of this invention. FIG. 2 is a schematic cross-sectional configuration diagram (part 2) in an example of a liquid crystal display device shown as the best mode for carrying out the present invention. It is FIG. (The 1) with which it uses for description of a prior art example. It is a figure which shows the state of the light of the support | pillar tip in a prior art example. It is a figure (the 2) with which it uses for description of a prior art example. It is the figure which showed the example of the state which the translucent base | substrate deform | transformed.

Explanation of symbols

  21 ... light emitting diode (LED), 21R ... red light emitting diode, 21G ... green light emitting diode, 21B ... blue light emitting diode, 30, 40 ... support, 30a, 41, 41a, 41b ... top (curved surface), 31,32 DESCRIPTION OF SYMBOLS ... Reflection angle control member, 31a ... Peripheral part, 31 ... Slope part, 60 ... Light-transmitting base | substrate, 70, 80 ... Support | pillar, 71 ... Auxiliary support | pillar, 81, 82 ... Locking part, 100 ... (Color) liquid crystal display device 140 ... Backlight device 141 ... Diffusion plate

Claims (17)

In a column supporting an optical structure on which direct light and indirect light from a light source are incident,
A support column, wherein a reflection angle control structure for controlling the amount of light irradiated from the periphery of the support column to the optical structure is formed in a part of the support column. The reflection angle control member comprising a convex portion formed in a plane substantially parallel to the incident surface of the optical structure is provided on the column surface as the reflection angle control structure. Prop. The mounting position and / or size of the reflection angle control member on the support column is determined based on an irradiation angle of a chief ray of light irradiated to the periphery of the top of the support column. Props. The support post according to claim 2, wherein an inclined surface facing the light source is formed on a peripheral edge of the reflection angle control member. The column according to claim 2, wherein the shape of the reflection angle control member is formed according to a luminance distribution on the surface of the optical structure. The strut according to claim 1, wherein a curved surface is formed at the top of the strut as the reflection angle control structure. The strut according to claim 6, wherein the amount of light reflected by the top of the head and irradiated to the optical structure is controlled by changing a radius of curvature of the curved surface of the top of the head. The said support | pillar is substantially conical shape. The support | pillar of Claim 1 characterized by the above-mentioned. In a backlight device having a column supporting an optical structure on which direct light and indirect light from a light source are incident,
A backlight device, wherein a reflection angle control structure for controlling an amount of light irradiated from the periphery of the support column to the optical structure is formed on a part of the support column. In a liquid crystal display device comprising a transmissive liquid crystal display panel and a backlight device in which a plurality of light sources are arranged to illuminate the liquid crystal display panel from the back side,
The backlight device includes a support column that supports an optical structure to which direct light and indirect light from the light source are incident, and light irradiated to the optical structure from a part of the support column from around the support column. A liquid crystal display device characterized in that a reflection angle control structure for controlling the amount of light is formed. In a backlight device in which a light-transmitting substrate is disposed substantially parallel to the optical structure between the optical structure on which light from a plurality of light sources is incident and the plurality of light sources.
A first support for supporting the light-transmitting substrate;
The backlight apparatus characterized by the 2nd support | pillar lower than the said 1st support | pillar and higher than said several light source being provided. The backlight device according to claim 11, wherein a pattern for reflecting or diffusing light irradiated directly from each light source is formed in a portion immediately above each light source of the light transmissive substrate. In a liquid crystal display device comprising a transmissive liquid crystal display panel and a backlight device in which a plurality of light sources are arranged to illuminate the liquid crystal display panel from the back side,
The backlight device includes a light-transmitting substrate disposed substantially parallel to the optical structure between the optical structure on which light from the light source is incident and the light source.
A first support for supporting the light-transmitting substrate;
A liquid crystal display device, wherein a second support column lower than the first support column and higher than the light source is provided. In a backlight device in which a light-transmitting substrate is disposed substantially parallel to the optical structure between the optical structure on which light from a plurality of light sources is incident and the plurality of light sources.
A first support that supports the optical structure and the light-transmitting substrate by a first locking portion and a second locking portion, respectively.
A backlight device comprising a second support column lower than the light-transmitting substrate supported by the first support column and higher than the plurality of light sources. A reflection angle control structure for controlling the amount of light irradiated from the periphery of the first support column to the optical structure is formed at a portion sandwiched between the light-transmitting substrate and the optical structure of the first support column. The backlight device according to claim 14. The backlight device according to claim 14, wherein a pattern that reflects or diffuses light irradiated directly from each light source is formed immediately above each light source of the light transmissive substrate. In a liquid crystal display device comprising a transmissive liquid crystal display panel and a backlight device in which a plurality of light sources are arranged to illuminate the liquid crystal display panel from the back side,
The backlight device includes a light-transmitting substrate disposed substantially parallel to the optical structure between the optical structure on which light from the light source is incident and the light source.
A first support that supports the optical structure and the light-transmitting substrate by a first locking portion and a second locking portion, respectively.
2. A liquid crystal display device comprising: a second support column which is lower than the light-transmitting substrate supported by the first support column and which is higher than the plurality of light sources.

Images