JP2008304502A - Backlight unit for liquid crystal panel and image display device using same - Google Patents
Backlight unit for liquid crystal panel and image display device using same Download PDFInfo
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- JP2008304502A JP2008304502A JP2007148860A JP2007148860A JP2008304502A JP 2008304502 A JP2008304502 A JP 2008304502A JP 2007148860 A JP2007148860 A JP 2007148860A JP 2007148860 A JP2007148860 A JP 2007148860A JP 2008304502 A JP2008304502 A JP 2008304502A
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Abstract
Description
本発明は、液晶パネル用バックライトユニット及び該バックライトユニットを用いた画像表示装置に関し、具体的には発光ダイオードを用いたバックライトユニットで照射される液晶表示装置に関する。 The present invention relates to a backlight unit for a liquid crystal panel and an image display device using the backlight unit, and more particularly to a liquid crystal display device irradiated with a backlight unit using a light emitting diode.
従来から、液晶パネルに画像を表示させる液晶表示装置が知られており、該液晶表示装置はバックライトユニットにて液晶パネルの表示面の反対側から液晶パネルを照射する。このバックライトユニットには、冷陰極管を用いたものがある。
図４は、従来の冷陰極管(25)を用いたバックライトユニット(２)と、該バックライトユニット(２)に照射される液晶パネル(５)の斜視図である(特許文献１参照)。該バックライトユニット(２)は基板(３)上に導光板(35)と、該導光板(35)の上下端部にて横向きに配備された冷陰極管(25)(25)とによって構成される。冷陰極管(25)(25)から放射された光は、導光板(35)内にて多重反射されて導光板(35)の前面から出射する。該光が液晶パネル(５)を照射し、斯種の構造は一般に小型の液晶表示装置に用いられることが多い。
冷陰極管(25)は水銀ランプの一種であり、縦向きに配備すると、内部の水銀が重力の影響を受けることや、冷陰極管(25)の上下端部に温度差が発生し易くなり、冷陰極管(25)の寿命に悪影響を及ぼすから、一般的に横向きに配備している。
大型の液晶表示装置用のバックライトユニット(２)としては、図５に示すように、基板(３)上に複数本の冷陰極管(25)(25)を上下等間隔に配備したものが用いられることが多い。
2. Description of the Related Art Conventionally, a liquid crystal display device that displays an image on a liquid crystal panel is known, and the liquid crystal display device irradiates the liquid crystal panel from the opposite side of the display surface of the liquid crystal panel with a backlight unit. Some backlight units use cold cathode tubes.
FIG. 4 is a perspective view of a backlight unit (2) using a conventional cold cathode tube (25) and a liquid crystal panel (5) irradiated to the backlight unit (2) (see Patent Document 1). . The backlight unit (2) is composed of a light guide plate (35) on a substrate (3) and cold cathode tubes (25) (25) arranged horizontally at the upper and lower ends of the light guide plate (35). Is done. The light emitted from the cold cathode tubes (25) and (25) is multiple-reflected in the light guide plate (35) and emitted from the front surface of the light guide plate (35). The light illuminates the liquid crystal panel (5), and this type of structure is generally used for small liquid crystal display devices.
The cold-cathode tube (25) is a type of mercury lamp. If it is installed vertically, the mercury inside will be affected by gravity and temperature differences will easily occur at the upper and lower ends of the cold-cathode tube (25). Since the cold cathode tube (25) has an adverse effect on the service life, it is generally installed sideways.
As a backlight unit (2) for a large liquid crystal display device, as shown in FIG. 5, a plurality of cold-cathode tubes (25) and (25) are arranged on a substrate (3) at equal intervals in the vertical direction. Often used.
図４及び図５のように、冷陰極管(25)を用いたバックライトユニット(２)では画面の上下で冷陰極管(25)(25)の配置密度に故意にバラ付きを持たせたり、上下中央部の冷陰極管(25)と上下端部の冷陰極管(25)の駆動電流に差を設けて、画面の上下に亘って輝度差を設けることはできる。しかし、画面の左右方向の中央部と左右端部とで輝度差を設けることはできない。
また、斯種のバックライトユニット(２)には、図６に示すように、冷陰極管(25)に代えて、多数の発光素子である発光ダイオード(４)(４)を基板(３)上に縦横に等間隔に配列して、液晶パネル(５)を一様な輝度に照射するものもある(特許文献２参照)。
As shown in FIGS. 4 and 5, in the backlight unit (2) using the cold cathode tube (25), the arrangement density of the cold cathode tubes (25) and (25) is intentionally varied at the top and bottom of the screen. A difference in luminance can be provided across the top and bottom of the screen by providing a difference in driving current between the cold cathode tubes (25) at the upper and lower central portions and the cold cathode tubes (25) at the upper and lower ends. However, it is not possible to provide a luminance difference between the center portion in the left-right direction and the left and right end portions of the screen.
Further, in this type of backlight unit (2), as shown in FIG. 6, in place of the cold cathode tube (25), light emitting diodes (4) and (4), which are a large number of light emitting elements, are provided on a substrate (3). Some of them are arranged vertically and horizontally at equal intervals to irradiate the liquid crystal panel (5) with uniform brightness (see Patent Document 2).
液晶表示装置は、電子看板等の特殊用途を除き、横長に画像を表示するのに用いられるのが殆どである。特に、テレビジョン受像機として利用される場合は、画面が横長に設置されて、視聴者の視線は画面中央部に集中するのが一般的である。出願人はこの点に鑑みて、画面の横方向中央部の輝度を上げ、周辺部の輝度を下げれば、視聴者の目の疲れを和らげることができ、且つ節電することもできることを着想した。
本発明の目的は、節電することができ、且つ視聴者の目の疲れを和らげることができる画像表示装置を提供することにある。
Liquid crystal display devices are mostly used to display images in landscape orientation except for special applications such as electronic signboards. In particular, when used as a television receiver, the screen is generally installed horizontally, and the viewer's line of sight is generally concentrated in the center of the screen. In view of this point, the applicant has conceived that if the luminance at the center in the horizontal direction of the screen is increased and the luminance at the peripheral portion is decreased, the viewer's eyes can be relieved and power can be saved.
An object of the present invention is to provide an image display device that can save power and relieve viewers' eyes.
バックライトユニット(２)は、基板(３)上に複数の発光素子を上下左右に配列し、該発光素子は基板(３)上の左右中央部にて密に配置され、少なくとも左右端部にて粗に配置されている。 The backlight unit (2) has a plurality of light emitting elements arranged vertically and horizontally on the substrate (3), and the light emitting elements are densely arranged at the left and right central portions on the substrate (3), and at least at the left and right ends. Are roughly arranged.
上記の如く、発光素子を配列することにより、画面の左右方向の中央部の輝度を高く、左右端部の輝度を低くすることができる。これにより、視聴者の視線が集中する画面の横方向中央部の輝度を集中的に上げることができ、視聴者の目の疲れを和らげることができる。また、画面の左右方向中央部に集中的に発光素子を配備すれば、基板(３)の全体に用いられる発光素子の総数を減らすこともでき、これによって、節電することもできる。 As described above, by arranging the light emitting elements, it is possible to increase the luminance of the central portion in the horizontal direction of the screen and decrease the luminance of the left and right end portions. Thereby, the brightness | luminance of the horizontal direction center part of the screen where a viewer's eyes | visual_axis concentrates can be raised intensively, and a viewer's eyes can be relieved. Further, if light emitting elements are centrally arranged in the central portion in the left-right direction of the screen, the total number of light emitting elements used for the entire substrate (3) can be reduced, thereby saving power.
以下、本発明の一実施例を図を用いて詳述する。
(第１実施例)
図１は、本例に係わる画像表示装置(１)のブロック図である。従来と同様に、液晶パネル(５)は背面からバックライトユニット(２)によって照射され、該バックライトユニット(２)は電源(６)からバックライト駆動回路(20)を介して給電される。バックライト駆動回路(20)は、バックライトユニット(２)に供給する駆動電流を制御する。電源(６)は液晶パネル(５)にも給電し、外部からの映像信号はタイミング制御回路(60)を介して、液晶パネルドライバ(50)に供給され、該液晶パネルドライバ(50)は液晶パネル(５)上にＸ、Ｙ方向に多数配列された液晶セルに給電して、液晶パネル(５)に映像が表示される。
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
(First embodiment)
FIG. 1 is a block diagram of an image display apparatus (1) according to this example. As in the prior art, the liquid crystal panel (5) is illuminated from the back by the backlight unit (2), and the backlight unit (2) is supplied with power from the power source (6) via the backlight drive circuit (20). The backlight drive circuit (20) controls the drive current supplied to the backlight unit (2). The power supply (6) also supplies power to the liquid crystal panel (5), and the video signal from the outside is supplied to the liquid crystal panel driver (50) via the timing control circuit (60), and the liquid crystal panel driver (50) Power is supplied to a large number of liquid crystal cells arranged in the X and Y directions on the panel (5), and an image is displayed on the liquid crystal panel (5).
図２は、バックライトユニット(２)の正面図である。以下では、発光素子として発光ダイオード(４)を挙げるが、これに限定されない。バックライトユニット(２)は基板(３)上に多数の発光ダイオード(４)(４)を縦横に配列して構成され、基板(３)は画面に対応して、横長に形成される。即ち、基板(３)の縦横は、画面の縦横に対応している。発光ダイオード(４)は白色ダイオードであっても、Ｒ、Ｇ、Ｂに対応したダイオードの組み合わせであってもよい。
本例では、基板(３)の左右中央部に発光ダイオード(４)(４)を密に配置し、左右端部で粗に配置した点に特徴がある。ここで密とは密度が高いの意味であり、単位面積当たりの発光ダイオード(４)(４)の数が多いことを指す。また、粗とは密度が低いの意味であり、単位面積当たりの発光ダイオード(４)(４)の数が少ないことを指す。また、各発光ダイオード(４)への供給電流は略均一のレベルとする。
図２の如く、発光ダイオード(４)(４)を配列することにより、画面の左右方向の中央部の輝度を高く、左右端部の輝度を低くすることができる。これにより、視聴者の視線が集中する画面の横方向中央部の輝度を集中的に上げることができ、視聴者の目の疲れを和らげることができる。また、画面の左右方向中央部に集中的に発光ダイオード(４)(４)を配備すれば、基板(３)の全体に用いられる発光ダイオード(４)の総数を減らすことができ、これによって、節電することもできる。更に、一般に発光ダイオード(４)は駆動電流が大きくなると、寿命が短くなるが、本例では各発光ダイオード(４)への供給電流は略均一レベルであるから、各発光ダイオード(４)の寿命に差異はない。
FIG. 2 is a front view of the backlight unit (2). Below, although a light emitting diode (4) is mentioned as a light emitting element, it is not limited to this. The backlight unit (2) is formed by arranging a large number of light emitting diodes (4) and (4) vertically and horizontally on a substrate (3), and the substrate (3) is formed horizontally corresponding to the screen. That is, the vertical and horizontal directions of the substrate (3) correspond to the vertical and horizontal directions of the screen. The light emitting diode (4) may be a white diode or a combination of diodes corresponding to R, G, and B.
This example is characterized in that the light emitting diodes (4) and (4) are densely arranged at the left and right central portions of the substrate (3) and are roughly arranged at the left and right end portions. Here, dense means that the density is high, and means that the number of light emitting diodes (4) and (4) per unit area is large. The term “rough” means that the density is low, and it means that the number of light emitting diodes (4) and (4) per unit area is small. The supply current to each light emitting diode (4) is set to a substantially uniform level.
As shown in FIG. 2, by arranging the light emitting diodes (4) and (4), it is possible to increase the luminance at the central portion in the horizontal direction of the screen and decrease the luminance at the left and right end portions. Thereby, the brightness | luminance of the horizontal direction center part of the screen where a viewer's eyes | visual_axis concentrates can be raised intensively, and a viewer's eyes can be relieved. Further, if the light emitting diodes (4) and (4) are intensively arranged at the central portion in the left and right direction of the screen, the total number of light emitting diodes (4) used for the entire substrate (3) can be reduced. You can also save power. Furthermore, the light emitting diode (4) generally has a shorter life when the driving current is increased. In this example, the current supplied to each light emitting diode (4) is at a substantially uniform level. There is no difference.
(第２実施例)
図３は、別のバックライトユニット(２)の正面図である。本例では、横方向のみならず、上下(縦)方向にも、発光ダイオード(４)の配列に粗密を設けている。具体的には、基板(３)の左右方向及び上下方向中央部に、発光ダイオード(４)(４)を密に配置し、上下端部を含む周辺部で粗に配置している。これによっても、第１実施例と同様に、視聴者の目の疲れを和らげることができるとともに、節電することもできる。
また、第１実施例に於いて、基板(３)上に密に配列された左右方向中央部の発光ダイオード(４)に大きな駆動電流を流して輝度を上げ、基板(３)上に粗に配列された左右端部の発光ダイオード(４)に小さな駆動電流を流して輝度を下げてもよい。この場合は、図１に示すタイミング制御回路(60)はバックライト駆動回路(20)に繋がって、基板(３)上の位置に応じて各発光ダイオード(４)に強弱の差を設けた駆動電流を流す。
また、第２実施例に示すように、基板(３)上に密に配列された上下方向中央部の発光ダイオード(４)に大きな駆動電流を流して輝度を上げ、基板(３)上に粗に配列された上下端部の発光ダイオード(４)に小さな駆動電流を流して輝度を下げてもよい。
(Second embodiment)
FIG. 3 is a front view of another backlight unit (2). In this example, the arrangement of the light-emitting diodes (4) is not only in the horizontal direction but also in the vertical (vertical) direction. Specifically, the light emitting diodes (4) and (4) are densely arranged at the center in the left and right direction and the up and down direction of the substrate (3), and are roughly arranged at the periphery including the upper and lower ends. In this way, as in the first embodiment, the viewer's eyes can be relieved and power can be saved.
Further, in the first embodiment, a large drive current is passed through the light emitting diodes (4) arranged in the center in the left-right direction densely arranged on the substrate (3) to increase the brightness, and the substrate (3) is roughened. The luminance may be lowered by passing a small drive current through the light emitting diodes (4) at the left and right end portions arranged. In this case, the timing control circuit (60) shown in FIG. 1 is connected to the backlight drive circuit (20), and the light emitting diode (4) is driven with a difference in strength depending on the position on the substrate (3). Apply current.
In addition, as shown in the second embodiment, a large drive current is passed through the light emitting diodes (4) in the center in the vertical direction densely arranged on the substrate (3) to increase the luminance, and the substrate (3) is roughened. The luminance may be lowered by passing a small drive current through the light emitting diodes (4) at the upper and lower ends arranged in the above.
上記実施例の説明は、本発明を説明するためのものであって、特許請求の範囲に記載の発明を限定し、或は範囲を減縮する様に解すべきではない。又、本発明の各部構成は上記実施例に限らず、特許請求の範囲に記載の技術的範囲内で種々の変形が可能であることは勿論である。 The above description of the embodiments is for explaining the present invention, and should not be construed as limiting the invention described in the claims or reducing the scope thereof. In addition, the configuration of each part of the present invention is not limited to the above embodiment, and various modifications can be made within the technical scope described in the claims.
(１) 画像表示装置
(２) バックライトユニット
(３) 基板
(４) 発光ダイオード
(５) 液晶パネル
(20) バックライト駆動回路
(1) Image display device
(2) Backlight unit
(3) Board
(4) Light emitting diode
(5) LCD panel
(20) Backlight drive circuit
Claims (5)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2007148860A JP2008304502A (en) | 2007-06-05 | 2007-06-05 | Backlight unit for liquid crystal panel and image display device using same |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2007148860A JP2008304502A (en) | 2007-06-05 | 2007-06-05 | Backlight unit for liquid crystal panel and image display device using same |
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| Publication Number | Publication Date |
|---|---|
| JP2008304502A true JP2008304502A (en) | 2008-12-18 |
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| Application Number | Title | Priority Date | Filing Date |
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| JP2007148860A Pending JP2008304502A (en) | 2007-06-05 | 2007-06-05 | Backlight unit for liquid crystal panel and image display device using same |
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| Country | Link |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2011001751A1 (en) * | 2009-06-30 | 2011-01-06 | シャープ株式会社 | Lighting device, display apparatus, and television receiving equipment |
| WO2011001749A1 (en) * | 2009-06-30 | 2011-01-06 | シャープ株式会社 | Lighting device, display apparatus, and television receiving equipment |
| WO2012101715A1 (en) * | 2011-01-25 | 2012-08-02 | パナソニック株式会社 | Backlight device and liquid crystal display device |
| JP2012150891A (en) * | 2011-01-17 | 2012-08-09 | Sharp Corp | Plane-irradiation light source device |
| WO2018168780A1 (en) * | 2017-03-17 | 2018-09-20 | シャープ株式会社 | Display method for display device, display device, and head-mount display device |
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| WO2004038283A1 (en) * | 2002-10-22 | 2004-05-06 | Sharp Kabushiki Kaisha | Backlight unit and liquid crystal display unit using backlight unit |
| JP2008286955A (en) * | 2007-05-17 | 2008-11-27 | Mitsubishi Electric Corp | Backlight device for display panel and liquid crystal display device |
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| WO2004038283A1 (en) * | 2002-10-22 | 2004-05-06 | Sharp Kabushiki Kaisha | Backlight unit and liquid crystal display unit using backlight unit |
| JP2008286955A (en) * | 2007-05-17 | 2008-11-27 | Mitsubishi Electric Corp | Backlight device for display panel and liquid crystal display device |
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011001751A1 (en) * | 2009-06-30 | 2011-01-06 | シャープ株式会社 | Lighting device, display apparatus, and television receiving equipment |
| WO2011001749A1 (en) * | 2009-06-30 | 2011-01-06 | シャープ株式会社 | Lighting device, display apparatus, and television receiving equipment |
| JP5138813B2 (en) * | 2009-06-30 | 2013-02-06 | シャープ株式会社 | Lighting device, display device, and television receiver |
| JP5154695B2 (en) * | 2009-06-30 | 2013-02-27 | シャープ株式会社 | Lighting device, display device, and television receiver |
| RU2491475C1 (en) * | 2009-06-30 | 2013-08-27 | Шарп Кабусики Кайся | Lighting device, reflection device and television receiver |
| RU2491474C1 (en) * | 2009-06-30 | 2013-08-27 | Шарп Кабусики Кайся | Illumination device, display device and television receiver |
| US8520150B2 (en) | 2009-06-30 | 2013-08-27 | Sharp Kabushiki Kaisha | Lighting device, display device and television receiver |
| JP2012150891A (en) * | 2011-01-17 | 2012-08-09 | Sharp Corp | Plane-irradiation light source device |
| WO2012101715A1 (en) * | 2011-01-25 | 2012-08-02 | パナソニック株式会社 | Backlight device and liquid crystal display device |
| CN102893075A (en) * | 2011-01-25 | 2013-01-23 | 松下电器产业株式会社 | Backlight device and liquid crystal display device |
| US8801210B2 (en) | 2011-01-25 | 2014-08-12 | Panasonic Corporation | Backlight device and liquid crystal display apparatus |
| WO2018168780A1 (en) * | 2017-03-17 | 2018-09-20 | シャープ株式会社 | Display method for display device, display device, and head-mount display device |
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