JP2009037929A - Surface light source element and image display device using it - Google Patents
Surface light source element and image display device using it Download PDFInfo
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本発明は、面光源素子およびこれを備える液晶表示装置などの画像表示装置、さらに該画像表示装置を表示モジュールとして備えるパーソナルコンピュータ、コンピュータ用モニタ、ビデオカメラ、テレビ受信機、カーナビゲーションシステムなどの画像表示装置に関する。 The present invention relates to an image display device such as a surface light source element and a liquid crystal display device including the surface light source element, and a personal computer, a computer monitor, a video camera, a television receiver, a car navigation system, and the like provided with the image display device as a display module. The present invention relates to a display device.
液晶表示装置に代表される透過型の画像表示装置は、面状に光を発する面光源素子（バックライト）とドット状に画素が配置された透過型表示素子とで構成され、該透過型表示素子の各画素で面光源素子からの光の透過率がコントロールされることによって文字や映像などが表示される。面光源素子としては、ハロゲンランプ、反射板、レンズ等が組み合わされて出射光の輝度の分布が制御されるもの、蛍光管が導光板の端面に設けられて蛍光管からの光が端面と垂直な面から出射されるもの、蛍光管が導光板の直下に設けられたもの（直下型）などが挙げられる。 2. Description of the Related Art A transmissive image display device typified by a liquid crystal display device includes a surface light source element (backlight) that emits light in a planar shape and a transmissive display element in which pixels are arranged in a dot shape. Characters, images, and the like are displayed by controlling the light transmittance from the surface light source element in each pixel of the element. As a surface light source element, a halogen lamp, a reflector, a lens, etc. are combined to control the luminance distribution of the emitted light. A fluorescent tube is provided on the end surface of the light guide plate, and light from the fluorescent tube is perpendicular to the end surface. The light emitted from a flat surface, the one provided with a fluorescent tube directly under the light guide plate (direct type), and the like.
ハロゲンランプを利用した面光源素子は、高輝度を必要とする液晶プロジェクタに主に用いられる。一方、導光板を利用した面光源素子は薄型化が可能であるため、直視型の液晶ＴＶ、パーソナルコンピュータのディスプレイなどに用いられることが多い。これら導光板を利用した面光源素子では、通常、正面輝度や出射光の視野角特性を改善する目的で導光板の出射面側にプリズムシートや拡散シートを設けるが、さらなる薄型化を実現する手段としては、これらのシートの機能を合わせ持った出射光制御板が有効である。これら出射光制御板は入射面上に所望の視野角特性に合わせて決定される形状からなる凸部を有しており、導光板と出射光制御板を平行に配置するとともに、固定層を介して光学的に導光板と密着させることによって出射光制御板の出射面から出射する光を制御することが可能である（特許文献１参照）。 A surface light source element using a halogen lamp is mainly used in a liquid crystal projector that requires high luminance. On the other hand, since a surface light source element using a light guide plate can be thinned, it is often used for a direct-view liquid crystal TV, a display of a personal computer, and the like. In these surface light source elements using the light guide plate, a prism sheet or a diffusion sheet is usually provided on the exit surface side of the light guide plate for the purpose of improving the front luminance and the viewing angle characteristics of the emitted light. As such, an outgoing light control plate having the functions of these sheets is effective. These outgoing light control plates have a convex portion having a shape determined in accordance with a desired viewing angle characteristic on the incident surface, and the light guide plate and the outgoing light control plate are arranged in parallel and through a fixed layer. Thus, it is possible to control the light emitted from the emission surface of the outgoing light control plate by optically contacting the light guide plate (see Patent Document 1).
しかしながら、近年、これら面光源素子の薄型化と正面方向の輝度向上の要求はますます高まっており、一方で省エネルギーの観点から効率的に光を正面方向に偏向することが望まれている。薄型化には、導光板の厚みを薄くすることである程度は対応可能であるが、導光板の厚みが光源の発光部の厚み以下になると、導光板への光の入光効率が減少し、輝度の低下を招く。 However, in recent years, demands for thinning the surface light source elements and improving the luminance in the front direction are increasing, and on the other hand, it is desired to efficiently deflect the light in the front direction from the viewpoint of energy saving. Thinning can be supported to some extent by reducing the thickness of the light guide plate, but if the thickness of the light guide plate is less than the thickness of the light emitting part of the light source, the light incident efficiency to the light guide plate decreases, It causes a decrease in brightness.
そこで本発明は、前記の課題に鑑みてなされたもので、導光板の厚みが光源の発光厚みより薄くなった場合でも、入光効率の減少を軽減し、輝度の高い面光線素子を提供する。 Accordingly, the present invention has been made in view of the above problems, and provides a high-luminance surface light element that reduces the reduction in light incident efficiency even when the thickness of the light guide plate is thinner than the light emission thickness of the light source. .
上記課題を解決する面光源素子は、光源と、前記光源からの光を受光する少なくとも１つの端面である入射面と該入射面と略垂直を成す主面の一つである出射面とを有する導光板と、前記導光板の出射面からの光を入射面上の凸部で受光して出射面から正面方向へ出射する出射光制御板とを備える面光源素子であって、凸部が導光板と光学的に密着してなり、光源配置側において導光板端面と出射光制御板端面が略同一面上にあり、光源配置側端面から少なくとも０．５ｍｍの範囲で導光板の出射面と出射光制御板が面状で光学的に密着してなり、導光板の厚みをＴ１、出射光制御板の厚みをＴ２、光源の導光板厚み方向の発光長をＨとした場合、
Ｔ１＜Ｈ＜Ｔ１＋Ｔ２ （１）
であることを特徴とする。
A surface light source element that solves the above problems includes a light source, an incident surface that is at least one end surface that receives light from the light source, and an exit surface that is one of main surfaces substantially perpendicular to the incident surface. A surface light source element comprising: a light guide plate; and an output light control plate that receives light from an exit surface of the light guide plate by a convex portion on an incident surface and emits the light from the exit surface in a front direction. The light guide plate end face and the outgoing light control plate end face are substantially on the same plane on the light source arrangement side, and are at least 0.5 mm from the light source arrangement side end face. When the emission control plate is planar and optically in close contact, the thickness of the light guide plate is T 1 , the thickness of the emitted light control plate is T 2 , and the light emission length of the light source in the thickness direction of the light guide plate is H,
T 1 <H <T 1 + T 2 (1)
It is characterized by being.
本発明の画像表示装置は上記の面光源素子の出射面側に透過型表示素子を設けたことを特徴とする。 The image display apparatus of the present invention is characterized in that a transmissive display element is provided on the exit surface side of the surface light source element.
通常、図４に示すように導光板３と導光板３の発光面側に出射光制御板４を用いた面光源では、導光板３の厚みＴ１が、光源２における発光部１０の厚さ方向の長さ（発光長Ｈ）よりも薄くなると、漏れ光が発生し光の損失を招く。このために導光板３への入射光量が減少し、輝度の低下を招く。
本発明では、図２に示すように光源配置側端面から少なくとも０．５ｍｍの範囲で導光板３の出射面と出射光制御板４が光学的に密着している。また導光板３の端面と出射光制御板４の端面が略同一面上にある。
Usually, in the surface light source using the outgoing light control plate 4 on the light emitting surface side of the light guide plate 3 and the light guide plate 3 as shown in FIG. 4, the thickness T 1 of the light guide plate 3 is the thickness of the light emitting unit 10 in the light source 2. When it becomes thinner than the length in the direction (light emission length H), leakage light is generated, causing loss of light. For this reason, the amount of light incident on the light guide plate 3 is reduced, leading to a reduction in luminance.
In the present invention, as shown in FIG. 2, the exit surface of the light guide plate 3 and the exit light control plate 4 are in optical contact within a range of at least 0.5 mm from the end surface on the light source arrangement side. The end face of the light guide plate 3 and the end face of the outgoing light control plate 4 are substantially on the same plane.
さらに導光板３の厚みをＴ１、出射光制御板４の厚みをＴ２、光源２における発光部１０の導光板厚み方向の発光長をＨとした場合、
Ｔ１＜Ｈ＜Ｔ１＋Ｔ２ （１）
を満足している。
つまり光源から出射した光は、低損失で、導光板３の端部および出射光制御板４の端部に入射する。つまり導光板の厚みよりも発光部の大きな光源を用いた場合でも、光の損失を低減し、高い輝度を有する面光源素子を得ることができる。
Furthermore, when the thickness of the light guide plate 3 is T 1 , the thickness of the outgoing light control plate 4 is T 2 , and the light emission length in the light guide plate thickness direction of the light emitting unit 10 in the light source 2 is H,
T 1 <H <T 1 + T 2 (1)
Is satisfied.
That is, the light emitted from the light source is incident on the end of the light guide plate 3 and the end of the outgoing light control plate 4 with low loss. That is, even when a light source having a light emitting portion larger than the thickness of the light guide plate is used, a surface light source element having high luminance can be obtained with reduced light loss.
また本発明の該面光源素子は正面方向の輝度が高いため、この出射面側に透過型表示素子を設けることにより、好ましい画像表示装置として利用できる。ここで、画像表示装置とは、面光源素子と透過型表示素子を組み合わせた表示モジュール、さらには、この表示モジュールを用いたテレビ、パソコンモニターなどの少なくとも画像表示機能を有する機器のことを言う。 Further, since the surface light source element of the present invention has high brightness in the front direction, it can be used as a preferable image display device by providing a transmission type display element on the exit surface side. Here, the image display device refers to a display module in which a surface light source element and a transmissive display element are combined, and a device having at least an image display function such as a television and a personal computer monitor using the display module.
以下、本発明の実施形態について図面を参照しながら詳しく説明する。
図１は本発明の実施形態に係る面光源素子の一部断面を示す概略断面図を示す。この面光源素子は、左右の端面１側に光源２が設けられた導光板３と、導光板３から出射された光の出射角度の分布を制御する出射光制御板４からなっている。出射光制御板４は導光板３上に配置され、入射面５に入射した光が出射面（面光源素子の発光面）６から出射される。出射光制御板４の入射面５には、導光板３の出射面からの光を出射光制御板４の出射面６の正面方向に向かわせるために、多数の凸部７が形成されている。この凸部７の頂部は導光板３の出射面もしくは図示していない固定層に光学的に密着している。
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic cross-sectional view showing a partial cross section of a surface light source element according to an embodiment of the present invention. The surface light source element includes a light guide plate 3 provided with a light source 2 on the left and right end faces 1 side, and an outgoing light control plate 4 that controls the distribution of the outgoing angles of light emitted from the light guide plate 3. The outgoing light control plate 4 is disposed on the light guide plate 3, and light incident on the incident surface 5 is emitted from the outgoing surface (light emitting surface of the surface light source element) 6. A large number of convex portions 7 are formed on the incident surface 5 of the outgoing light control plate 4 in order to direct light from the outgoing surface of the light guide plate 3 toward the front of the outgoing surface 6 of the outgoing light control plate 4. . The top of the projection 7 is optically in close contact with the exit surface of the light guide plate 3 or a fixed layer (not shown).
光源２から導光板の入射面１へ入射した光は導光板３内を、全反射を繰り返し伝播していく。この伝播する光が出射光制御板４の凸部７の頂部との界面から出射光制御板４に取り込まれる。これにより、導光板３内および図示されない固定層内を伝播する光は界面から順次、出射光制御板４に取り出され、取り出された光は出射光制御板４の凸部７内で全反射されて出射面６から出射される。 Light incident on the incident surface 1 of the light guide plate from the light source 2 propagates through the light guide plate 3 repeatedly with total reflection. The propagating light is taken into the outgoing light control plate 4 from the interface with the top of the convex portion 7 of the outgoing light control plate 4. As a result, light propagating in the light guide plate 3 and in the fixed layer (not shown) is sequentially extracted from the interface to the outgoing light control plate 4, and the extracted light is totally reflected in the convex portion 7 of the outgoing light control plate 4. And exit from the exit surface 6.
本発明の面光源素子に用いる導光板としては、アクリル樹脂（ＰＭＭＡ）、ポリカーボネート樹脂（ＰＣ）、ポリスチレン樹脂（ＰＳ）、シクロオレフィンポリマー等の透明性に優れた樹脂またはガラスを所定の形状に加工したものを用いることができる。なかでもアクリル樹脂を用いるのが軽量性、透明性の点で好ましい。加工方法としては、押出し板若しくはキャスト板から切り出す方法または加熱プレス、射出成形等の溶融成形法などが好適に用いられるがこれに限定されるものではない。 As a light guide plate used in the surface light source element of the present invention, a resin or glass excellent in transparency such as acrylic resin (PMMA), polycarbonate resin (PC), polystyrene resin (PS), cycloolefin polymer, etc. is processed into a predetermined shape. Can be used. Among them, it is preferable to use an acrylic resin in terms of lightness and transparency. As a processing method, a method of cutting out from an extruded plate or a cast plate or a melt molding method such as a hot press or injection molding is preferably used, but is not limited thereto.
また、導光板３と出射光制御板４を光学的に密着させるには、導光板３と出射光制御板４との間に固定層を設けてもよい。固定層としては、接着剤、粘着剤、粘接着剤、光硬化性樹脂などが挙げられるが、取り扱い性や生産性の面から光硬化性の粘接着剤が好適に用いられる。粘着剤には、例えばゴム系やアクリル系、ビニルアルキルエーテル系やシリコーン系、ポリエステル系やポリウレタン系、ポリエーテル系やポリアミド系、スチレン系などの適宜なポリマーをベースポリマーとするものが挙げられる。中でも、アクリル酸ないしメタクリル酸のアルキルエステルを主体とするポリマーをベースポリマーとするアクリル系粘着剤が透明性や耐候性、耐熱性の点で優れるため、好適に用いられる。また、接着剤はそれに例えばシリカやアルミナ、チタニアやジルコニア、酸化錫や酸化インジウム、酸化カドミウムや酸化ノンモン等の導電性のある無機系粒子や、架橋または未架橋ポリマー等の有機系粒子などの適宜な透明粒子を１種又は２種以上含有させて光拡散型のものとすることもできる。 Further, in order to optically adhere the light guide plate 3 and the outgoing light control plate 4, a fixed layer may be provided between the light guide plate 3 and the outgoing light control plate 4. Examples of the fixing layer include an adhesive, a pressure-sensitive adhesive, an adhesive, a photocurable resin, and the like. A photocurable adhesive is preferably used from the viewpoints of handleability and productivity. Examples of the pressure-sensitive adhesive include those based on an appropriate polymer such as rubber, acrylic, vinyl alkyl ether, silicone, polyester, polyurethane, polyether, polyamide, and styrene. Among these, acrylic pressure-sensitive adhesives based on polymers mainly composed of alkyl esters of acrylic acid or methacrylic acid are preferred because they are excellent in transparency, weather resistance and heat resistance. In addition, the adhesive may be appropriately selected from conductive inorganic particles such as silica, alumina, titania and zirconia, tin oxide and indium oxide, cadmium oxide and nonmony oxide, and organic particles such as a crosslinked or uncrosslinked polymer. One kind or two or more kinds of transparent particles may be contained to obtain a light diffusion type.
さらに、導光板３の表面改質を行うことや、出射光制御板４における凸部７を形成する材料に自己粘着性を持たせることで、導光板３と出射光制御板４とを固定相を介さずに光学的に密着させてもよい。この場合は凸部７の先端に平坦部を設けることが好適である。この平坦部が密着することで、光学的密着部の幅を高い精度で得ることができる。 Furthermore, the light guide plate 3 and the outgoing light control plate 4 are fixed to each other by modifying the surface of the light guide plate 3 or providing the material forming the convex portions 7 of the outgoing light control plate 4 with self-adhesiveness. You may make it optically stick without going through. In this case, it is preferable to provide a flat portion at the tip of the convex portion 7. When the flat portion is in close contact, the width of the optical close contact portion can be obtained with high accuracy.
また、出射光制御板４の表面形状は、スタンパまたは雌金型などを用いて、熱プレス法、紫外線硬化による２Ｐ法、熱硬化によるキャスト法、射出成形法等によって透明な基材上に形成することができる。該透明な基材としては、アクリル樹脂、ポリカーボネート樹脂、ポリスチレン樹脂、シクロオレフィンポリマー等の樹脂またはガラスが用いられる。本発明においては、アクリル樹脂を用いた透明な基材上に光硬化性樹脂で形状を転写することが好適に用いられる。 Further, the surface shape of the outgoing light control plate 4 is formed on a transparent substrate by using a stamper or a female die, etc. by a hot press method, a 2P method by ultraviolet curing, a casting method by thermal curing, an injection molding method, or the like. can do. As the transparent substrate, resin such as acrylic resin, polycarbonate resin, polystyrene resin, cycloolefin polymer, or glass is used. In the present invention, it is preferable to transfer the shape with a photocurable resin onto a transparent substrate using an acrylic resin.
基材に転写する際に用いる光硬化性樹脂は、作製した出射光制御板の光学性能を決定するものであり、所望の性能に応じて適宜選択するのが好ましい。光硬化性樹脂の成分としては、ラジカル重合が可能なモノマー或いはオリゴマーを単独で或いは２種以上組み合わせて用いるが、通常２種以上を用いるのが好ましく、出射光制御板４に要求される機械的強度、耐衝撃性、耐熱性、表面硬度などを付与することができる。成分の具体例としては、脂肪族、脂環族、芳香族系のモノ又はポリアルコールとアクリル酸又はメタクリル酸との縮合反応で得られるエステル型（メタ）アクリレートや、分子内に2個以上のイソシアネート基を有するイソシアネート化合物とヒドロキシル基またはチオール基を含有する(メタ)アクリレートとのウレタン化反応で得られるウレタンポリ（メタ）アクリレートや分子内に少なくとも２個のエポキシ基を有する化合物とアクリル酸又はメタクリル酸とのグリシジル基開環反応で得られるエポキシポリ（メタ）アクリレートや、飽和又は不飽和多価カルボン酸、多価アルコール及び（メタ）アクリル酸との縮合反応で得られるポリエステル（メタ）アクリレート等の（メタ）アクリロイル官能性モノマー若しくはオリゴマーや、スチレン、クロロスチレン、ブロモスチレン、ジブロモスチレン、ジビニルベンゼン等のビニル化合物や、ジエチレングリコールビスアリルカーボネート、ジアリルフタレート、ジアリルビフェニレート等の（メタ）アリル化合物が挙げられる。これらの単量体は1種を単独で用いてもよいし、２種以上を混合してもよい。 The photocurable resin used when transferring to the substrate determines the optical performance of the produced outgoing light control plate, and is preferably selected as appropriate according to the desired performance. As a component of the photo-curing resin, a monomer or oligomer capable of radical polymerization is used alone or in combination of two or more, but usually two or more are preferably used, and the mechanical properties required for the outgoing light control plate 4 are used. Strength, impact resistance, heat resistance, surface hardness and the like can be imparted. Specific examples of the component include an ester type (meth) acrylate obtained by a condensation reaction of an aliphatic, alicyclic, or aromatic mono- or polyalcohol with acrylic acid or methacrylic acid, or two or more in the molecule. Urethane poly (meth) acrylate obtained by urethanization reaction of isocyanate compound having isocyanate group and (meth) acrylate containing hydroxyl group or thiol group and compound having at least two epoxy groups in the molecule and acrylic acid or Epoxy poly (meth) acrylate obtained by glycidyl group ring-opening reaction with methacrylic acid, polyester (meth) acrylate obtained by condensation reaction with saturated or unsaturated polyvalent carboxylic acid, polyhydric alcohol and (meth) acrylic acid (Meth) acryloyl functional monomers or oligomers such as Emissions, chlorostyrene, bromostyrene, dibromostyrene, and vinyl compounds such as divinylbenzene, diethylene glycol bis allyl carbonate, diallyl phthalate, (meth) allyl compounds such as diallyl biphenylene rate and the like. These monomers may be used individually by 1 type, and may mix 2 or more types.
出射光制御板４の作製に用いるスタンパは、例えばガラス基板上にネガ型あるいはポジ型の感光性樹脂をコーティングし、この感光性樹脂を、フォトマスクを介して露光するかまたはレーザー描画装置により露光し、現像後、電鋳を行うことにより作製することができるし、切削によって作製することもできる。 The stamper used for producing the outgoing light control plate 4 is, for example, coating a negative or positive photosensitive resin on a glass substrate, and exposing the photosensitive resin through a photomask or using a laser drawing apparatus. And it can produce by performing electroforming after image development, and can also produce by cutting.
導光板３の好適な厚さは０.１ｍｍ〜０．８ｍｍである。０．１ｍｍを下回ると自立性が低下し反りによる外観不良が発生する。また０．８ｍｍ以上では薄型化には適しない。さらに出射光制御板４の好適な厚さは０．０５ｍｍ〜０．３ｍｍで、０．１ｍｍ〜０．２ｍｍのフィルム状であることで装置の薄型化、軽量化密着性低下につながる応力の低減などの効果が得られる。０．０５ｍｍを下回ると導光板３との固定時の皺や物理的強度の低下から好ましくない。０．３ｍｍを超えると装置が重量化するため好ましくない。
また、本発明における出射光制御板４が備える凸部７としては、マイクロレンズアレイタイプ、レンチキュラーレンズタイプなどのものを用いることができる。
A suitable thickness of the light guide plate 3 is 0.1 mm to 0.8 mm. If the thickness is less than 0.1 mm, the self-supporting property is lowered, and appearance defects due to warpage occur. If the thickness is 0.8 mm or more, it is not suitable for thinning. Furthermore, the suitable thickness of the outgoing light control plate 4 is 0.05 mm to 0.3 mm, and the film shape of 0.1 mm to 0.2 mm reduces the thickness of the device and reduces the stress that leads to reduced weight and adhesion. Effects such as can be obtained. If it is less than 0.05 mm, it is not preferable because of wrinkles at the time of fixing to the light guide plate 3 and a decrease in physical strength. If it exceeds 0.3 mm, the apparatus becomes heavy, which is not preferable.
Moreover, as the convex part 7 with which the emitted light control board 4 in this invention is provided, things, such as a micro lens array type and a lenticular lens type, can be used.
出射光制御板４の光出射面には微細な表面凹凸を直接転写してもよいし、光透過性微粒子を混合させた拡散剤液を塗工することによって拡散層を設けても良い。拡散層により視野角特性がなだらかになり、良好な品位を得ることができる。 Fine surface irregularities may be directly transferred to the light exit surface of the exit light control plate 4, or a diffusion layer may be provided by applying a diffusing agent liquid mixed with light transmitting fine particles. A viewing angle characteristic becomes gentle by the diffusion layer, and good quality can be obtained.
また本発明に用いる薄型の光源としては、ＬＥＤなどの点状光源が挙げられる。点状光源の場合には、１個または複数個用いてもよい。この場合、点状光源を配置する導光板側面の中心に対して点状光源を対称に配置することが好ましい。この配置により面内の分布を対象にすることができ外観品位を向上することができる。一方、複数個用いる場合、点状光源の間隔は均等になるよう配置することが望ましい。これにより点状光源の近傍と点状光源間のムラを最小に抑えることができる。 Moreover, point light sources, such as LED, are mentioned as a thin light source used for this invention. In the case of a point light source, one or more may be used. In this case, it is preferable to arrange the point light sources symmetrically with respect to the center of the side surface of the light guide plate where the point light sources are arranged. With this arrangement, the in-plane distribution can be targeted and the appearance quality can be improved. On the other hand, when using two or more, it is desirable to arrange | position so that the space | interval of a point light source may become equal. As a result, unevenness between the vicinity of the point light source and the point light source can be minimized.
また、導光板３の入光側で、出射光制御板４と面状で密着している端面からの長さは少なくとも０．５ｍｍであることが必要であり、導光板３の厚みの３倍以上であることが望ましい。さらに望ましくは５倍以上である。
光源２における発光部１０の底部は、導光板３の底部に揃えることが望ましい。
Further, it is necessary that the length from the light-incident side of the light guide plate 3 from the end face in close contact with the outgoing light control plate 4 is at least 0.5 mm, which is three times the thickness of the light guide plate 3. The above is desirable. More desirably, it is 5 times or more.
The bottom of the light emitting unit 10 in the light source 2 is preferably aligned with the bottom of the light guide plate 3.
導光板３の入光側で、出射光制御板４と面状で密着している領域は、出射光制御板４の凸部７が形成される時に同時に形成することが望ましいが、一様に凸部７が形成された出射光制御板４を導光板３に接着する際に、図３に示すように端面近傍において出射光制御板４と屈折率が略同一の接着剤１１で凸部を埋めることで、面状で密着している領域を形成してもよい。 It is desirable to form the area in close contact with the outgoing light control plate 4 in a planar shape on the light incident side of the light guide plate 3 at the same time when the convex portion 7 of the outgoing light control plate 4 is formed. When the outgoing light control plate 4 formed with the convex portions 7 is bonded to the light guide plate 3, the convex portions are formed with an adhesive 11 having substantially the same refractive index as that of the outgoing light control plate 4 in the vicinity of the end face as shown in FIG. By filling the region, a close contact region may be formed.
以下、実施例によって、より具体的に本発明の効果を説明する。各実施例、並びに比較例では、図６に示すような構成の面光源素子の正面輝度を測定し、効果を確認した。何れの場合も、導光板短辺側面に光源として白色ＬＥＤ３個を配置し、面光源素子を得た。ＬＥＤの発光中心間距離は１０ｍｍとし、中央の１個は導光板側面の中央に配置した。面光源素子の中央部を発光面に対して垂直に５００ｍｍの距離から輝度計（トプコンテクノハウス製ＢＭ−７Ｆａｓｔ）により測定した。 Hereinafter, the effects of the present invention will be described more specifically by way of examples. In each example and comparative example, the front luminance of the surface light source element configured as shown in FIG. 6 was measured to confirm the effect. In any case, three white LEDs were disposed as light sources on the short side surface of the light guide plate to obtain a surface light source element. The distance between the light emission centers of the LEDs was 10 mm, and one at the center was arranged at the center of the side surface of the light guide plate. The central part of the surface light source element was measured with a luminance meter (BM-7Fast, manufactured by Topcon Technohouse) from a distance of 500 mm perpendicular to the light emitting surface.
＜実施例１＞
実施例１では、導光板３として、寸法が３０ｍｍ×４０ｍｍで厚み０．４ｍｍの平板状ＰＭＭＡを用い、出射面およびその対向する面は平坦面とした。出射光制御板４としては、基材として厚み０．１ｍｍのＰＭＭＡフィルムを用い、スタンパに光硬化性樹脂を塗布したものを紫外線硬化することで基材に転写して作製した。出射光制御板の総厚みは０．２ｍｍである。導光板の屈折率は１.４９であり、硬化後の光硬化性樹脂の屈折率は１.５４であった。該出射光制御板を導光板の出射面に貼り合わせた。光源側においては、導光板端部から３ｍｍまでは導光板と出射光制御板と光学的に全面密着しており、光源から３ｍｍ以上離れた場所から凸部を設けた。
<Example 1>
In Example 1, as the light guide plate 3, flat PMMA having a size of 30 mm × 40 mm and a thickness of 0.4 mm was used, and the emission surface and the opposing surface were flat surfaces. The emission light control plate 4 was prepared by using a PMMA film having a thickness of 0.1 mm as a base material and transferring the photo-curing resin applied to the stamper to the base material by UV curing. The total thickness of the outgoing light control plate is 0.2 mm. The refractive index of the light guide plate was 1.49, and the refractive index of the photocurable resin after curing was 1.54. The outgoing light control plate was bonded to the outgoing surface of the light guide plate. On the light source side, the light guide plate and the outgoing light control plate were optically in close contact with each other up to 3 mm from the end of the light guide plate, and a convex portion was provided from a location 3 mm or more away from the light source.
＜比較例１＞
比較例１では、導光板３として、寸法が３０ｍｍ×４０ｍｍで厚み０．４ｍｍの平板状ＰＭＭＡを用い、出射面およびその対向する面は平坦面とした。出射光制御板４としては、基材として厚み０．１ｍｍのＰＭＭＡフィルムを用い、スタンパに光硬化性樹脂を塗布したものを紫外線硬化することで基材に転写して作製した。出射光制御板の総厚みは０．２ｍｍである。導光板の屈折率は１.４９であり、硬化後の光硬化性樹脂の屈折率は１.５４であった。該出射光制御板を導光板の出射面に貼り合わせた。光源側においては、導光板端部から３ｍｍまでは出射光制御板は設けず、光源から３ｍｍ以上離れた場所から凸部を設けた。
<Comparative Example 1>
In Comparative Example 1, a flat PMMA having a size of 30 mm × 40 mm and a thickness of 0.4 mm was used as the light guide plate 3, and the emission surface and the opposing surface were flat surfaces. The emission light control plate 4 was prepared by using a PMMA film having a thickness of 0.1 mm as a base material and transferring the photo-curing resin applied to the stamper to the base material by UV curing. The total thickness of the outgoing light control plate is 0.2 mm. The refractive index of the light guide plate was 1.49, and the refractive index of the photocurable resin after curing was 1.54. The outgoing light control plate was bonded to the outgoing surface of the light guide plate. On the light source side, the emission light control plate was not provided up to 3 mm from the end of the light guide plate, and a convex portion was provided from a location 3 mm or more away from the light source.
実施例、比較例共に、導光板端部にＬＥＤ３個を等間隔に配置した。ＬＥＤの発光長は０．４５ｍｍである。
表１に上記実施例ならびに比較例の正面輝度の評価結果を示す。
In both the example and the comparative example, three LEDs were arranged at equal intervals at the end of the light guide plate. The light emission length of the LED is 0.45 mm.
Table 1 shows the evaluation results of the front luminance of the above examples and comparative examples.
１ 端面、２ 光源、３ 導光板、４ 出射光制御板
５ 入射面、６ 出射面、７ 凸部、１０ 発光部
１１ 接着剤
DESCRIPTION OF SYMBOLS 1 End surface, 2 Light source, 3 Light guide plate, 4 Outgoing light control board 5 Incident surface, 6 Outgoing surface, 7 Convex part, 10 Light emission part 11 Adhesive
Claims (3)
導光板の厚みをＴ１、出射光制御板の厚みをＴ２、光源の導光板厚み方向の発光長をＨとした場合、
Ｔ１＜Ｈ＜Ｔ１＋Ｔ２ （１）
であることを特徴とする面光源素子。 A light guide plate having a light source, an incident surface that is at least one end surface that receives light from the light source, and an emission surface that is one of main surfaces substantially perpendicular to the incident surface, and emission of the light guide plate A surface light source element including an outgoing light control plate that receives light from a surface by a convex portion on an incident surface and emits the light from the outgoing surface in a front direction, wherein the convex portion of the outgoing light control plate is optically coupled to the light guide plate The light guide plate end surface and the exit light control plate end surface are substantially on the same surface on the light source arrangement side, and the exit surface of the light guide plate and the exit light control plate are at least 0.5 mm from the end surface on the light source arrangement side. Is optically in close contact with the surface,
When the thickness of the light guide plate is T 1 , the thickness of the outgoing light control plate is T 2 , and the light emission length in the light guide plate thickness direction of the light source is H,
T 1 <H <T 1 + T 2 (1)
A surface light source element.
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| JP2007202245A JP2009037929A (en) | 2007-08-02 | 2007-08-02 | Surface light source element and image display device using it |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011086789A1 (en) * | 2010-01-18 | 2011-07-21 | シャープ株式会社 | Lighting device, display apparatus, and television receiver apparatus |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011086789A1 (en) * | 2010-01-18 | 2011-07-21 | シャープ株式会社 | Lighting device, display apparatus, and television receiver apparatus |
| CN102713412A (en) * | 2010-01-18 | 2012-10-03 | 夏普株式会社 | Lighting device, display apparatus, and television receiver apparatus |
| JP5368586B2 (en) * | 2010-01-18 | 2013-12-18 | シャープ株式会社 | Lighting device, display device, television receiver |
| RU2509259C1 (en) * | 2010-01-18 | 2014-03-10 | Шарп Кабусики Кайся | Lighting device, display device and tv receiver |
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