TWI337271B

TWI337271B - Light guide plate and backlight module

Info

Publication number: TWI337271B
Application number: TW93131353A
Authority: TW
Inventors: Di Feng; Xing-Peng Yang; Guo-Fan Jin; Qiao-Feng Tan; Ying-Bai Yan; Shou-Shan Fan
Original assignee: Hon Hai Prec Ind Co Ltd
Priority date: 2004-10-15
Filing date: 2004-10-15
Publication date: 2011-02-11
Also published as: TW200612135A

Description

1337.271 099年10月13日核正六、發明說明：【發明所屬之技術領域】 [0001]本發明涉及一種應用於液晶顯示領域之導光板及背光模組，尤其涉及一種側光式之導光板及背光模組。【先前技術】 [0002]導光板（Light Guide Plate，LGP)主要包括光入射面、反射面、出射面及幾個側面’係液晶顯示背光模組系統中之重要組成部分。其作用係引導分散點光源（例如發光二極管）或線光源（例如冷陰極管）發出之光線從一個平面出射，同時提高面板發光灰度及發光亮度之均句性。導光板一般採用合成樹脂材料製成，其基板形狀分為平板型與楔型曲面型。 [0003] [0004] 進入導光板之光線將根據全發射原理在板内傳播，當光線遇到導光板表面之微結構（pattern)時’全發射條件被破壞，光線自導光板正面射出，疏密、大小不同之微結構設計，可以使導光板均句發光。導光板微結構之製造技術可以分成兩大類：印刷式與非印刷式。前者利用網印方式將油墨印於導光板上，製作出微結構形狀及其分佈。後者則直接以射出成型技術，將微結構設計於模於製程上較為續化，而且精密度高，係目前導光板製造技術之主流。非印刷式製作方法又分為：化學刻钱法、録射直寫法與精密機械加工法等。 093131353 uispiay，LCD)於堵如手機、車載顯示器、個 81人數字助理（Personal Distal Assistant, pda、及電視機等應用領域之拓展表單編號A010丨第3百/u „ 第3頁/共26頁 0993367629- 1337271 099年 10月 13 ’對以導光板為主之背光技術提出了更高要求，主要表現在：高亮度、低成本、低能耗，輕薄化等。1337.271 October 13th, 1999, the invention of the invention: [Technical field] [0001] The present invention relates to a light guide plate and a backlight module used in the field of liquid crystal display, and more particularly to a side light type light guide plate and Backlight module. [Prior Art] [0002] Light Guide Plate (LGP) mainly includes light incident surface, reflective surface, exit surface and several side surfaces, which are important components in the liquid crystal display backlight module system. Its function is to guide the light emitted by a scattered point source (such as a light emitting diode) or a line source (such as a cold cathode tube) to exit from a flat surface, and at the same time improve the uniformity of the panel gradation and illuminance. The light guide plate is generally made of a synthetic resin material, and the shape of the substrate is divided into a flat plate type and a wedge type curved surface type. [0003] [0004] The light entering the light guide plate will propagate in the plate according to the principle of full emission. When the light encounters the pattern of the surface of the light guide plate, the full emission condition is destroyed, and the light is emitted from the front surface of the light guide plate. The micro-structure design with different density and size can make the light guide plate emit light uniformly. The manufacturing technology of the light guide plate microstructure can be divided into two categories: printed and non-printed. The former uses a screen printing method to print ink on the light guide plate to produce a microstructure shape and its distribution. In the latter case, the injection molding technology is adopted directly, and the microstructure design is more continuous in the process, and the precision is high, which is the mainstream of the current light guide plate manufacturing technology. Non-printing methods are divided into: chemical engraving method, direct recording method and precision machining method. 093131353 uispiay, LCD) Expansion of the application form such as mobile phone, car display, 81-person digital assistant (Personal Distal Assistant, pda, and TV) Form number A010丨3// „ Page 3 of 26 0993367629- 1337271 October 13 099 'There are higher requirements for backlight technology based on light guides, mainly in: high brightness, low cost, low energy consumption, thin and light.

[0005] 請參閱第一圖，從光束之入射角度看，為了使更多能量入射到LGP，一般係於LGP之入射面做成凹槽，然後將作為光源之發光二極管（Light Emission Diode，LED )置於其中。這種内置光源之設計將使得LGP較厚，不利於輕薄化設計，而且由於LED内置，散熱差，將影響LGP 之正常使用。 [0006] 請參閱第二圖，第6,421，104號美國專利直接用傳統之折射型透鏡置於光源後面，其設計靈活性與結構緊湊性都比較差。 [〇〇〇7]請參閱第三圖，丨998年7月31曰公開之公開號為特開平 1 0-1 9931 6日本專利申請，採用於LGP入射面加工V型結構來改變LED之入射角度，但其設計靈活性差，而且耦合效率比較低。 [0008]請參閱第四圖與第五圖，2003年11月20日公開之公開號為20030214818之美國專利申請採用了類似於圖3之設計，由於其採用周期結構之V型刻槽，對光束之控制能力有限，私合效率也不高。 [〇〇〇9]目前，基於光波繞射理論之繞射光學元件（Diffmct- ive Optical Elements， DOEs) 有著體積小、重量輕、極大設計自由度、寬廣之材料選擇性等優點，於實現光波變換上具有許多卓越的、傳統光學難以實現之功能 ’被廣泛應用于諸如错射聚焦、搞合、光譜渡波、相關 093131353 表單編號A0101 第4頁/共26頁 0993367629-0 1337271 099年10月13日後正替換頁濾波、光束整形（Beam shaping)、波長區間多工與信號處理等多個領域： [0010] 請參閱第六圖，2003年10月21日公告之第6, 636, 283號美國專利提出一種結構將繞射微透鏡製作在基板上，然後置於光源與LGP之間，起到將入射光准直後入射到LGP 之作用。這種設計可實現輕薄化設計，但是由於它係分離式設計，系統之橫向尺寸較大，系統結構複雜，不利於提高能量利用率。 [00Π] 因此，有必要提供一種能提高能量利用率且結構緊湊之 ® 導光板及使用該種導光板之背光模組。【發明内容】 [0012] 本發明所要解決之第一個技術問題係：提供一種導光板，能提高能量利用率且結構緊湊。 [0013] 本發明所要解決之第二個技術問題係：提供一種背光模組，其具有上述導光板’能提高能量利用率且結構緊湊 [0014] 為解決上述第一個技術問題’本發明提供之技術方案係 :一種導光板，包括一入射面、一出射面及一設有若干微結構之反射面，該入射面形成有至少一個繞射結構。 [0015] 其中，所述繞射結構最好為非球面繞射結構。 [0016] 所述#球面繞射結構之相位延遲又)最好滿足下式： [0017] 093131353 表單編號A0101 第5買/共26頁 0993367629-0 1337271 099年10月13日修正替换頁 [0018] 其中f為該非球面繞射結構焦距，n2為焦點處之折射率， λ為真空中入射波長，七為真空中波數， X為該非球面繞射結構表面之任意點到其中心軸之距離。 [0019] 所述非球面繞射結構之深度y(x)最好滿足下式： [0020] _^-[0005] Referring to the first figure, in order to make more energy incident on the LGP from the incident angle of the light beam, the incident surface of the LGP is generally made into a groove, and then the light emitting diode (Light Emission Diode, LED) is used as a light source. ) placed in it. The design of this built-in light source will make the LGP thicker, which is not conducive to thin and light design, and due to the built-in LED, poor heat dissipation will affect the normal use of LGP. [0006] Referring to the second figure, U.S. Patent No. 6,421,104 is directly placed behind a light source by a conventional refractive lens, and its design flexibility and compactness are relatively poor. [〇〇〇7] Please refer to the third figure, published in July 31, 998, published in Japanese Patent Application No. 1 0-1 9931 6 Japanese Patent Application, which uses a V-shaped incident surface to process the V-shaped structure to change the incident of the LED. Angle, but its design flexibility is poor, and the coupling efficiency is relatively low. [0008] Referring to the fourth and fifth figures, the U.S. Patent Application Publication No. 20030214818, issued on Nov. 20, 2003, uses a design similar to that of Figure 3, due to its use of a V-shaped groove of a periodic structure, The control ability of the beam is limited, and the efficiency of the private combination is not high. [〇〇〇9] At present, Diffm- ive Optical Elements (DOEs) based on the theory of light wave diffraction have the advantages of small size, light weight, great design freedom, wide material selectivity, etc. The transformation has many excellent functions that are difficult to achieve with traditional optics'. It is widely used in such things as misfocus focusing, fitting, spectral crossing, related 093131353 Form No. A0101 Page 4 / Total 26 Page 0993367629-0 1337271 099 October 13 In the future, it will replace page filtering, beam shaping, wavelength interval multiplexing and signal processing, etc. [0010] Please refer to the sixth picture, US Patent No. 6, 636, 283 of October 21, 2003 The patent proposes a structure in which a diffraction microlens is fabricated on a substrate and then placed between the light source and the LGP to collimate the incident light and then enter the LGP. This design allows for a slim and light design, but because of its separate design, the system has a large lateral dimension and a complex system structure, which is not conducive to improving energy efficiency. [00Π] Therefore, it is necessary to provide a compact light guide plate and a backlight module using the same that can improve energy utilization. SUMMARY OF THE INVENTION [0012] The first technical problem to be solved by the present invention is to provide a light guide plate which can improve energy utilization and has a compact structure. [0013] A second technical problem to be solved by the present invention is to provide a backlight module having the above-mentioned light guide plate' capable of improving energy utilization and compact structure [0014] In order to solve the above first technical problem, the present invention provides The technical solution is a light guide plate comprising an incident surface, an exit surface and a reflective surface provided with a plurality of microstructures, the incident surface being formed with at least one diffraction structure. [0015] wherein the diffraction structure is preferably an aspherical diffraction structure. [0016] The phase delay of the #spherical diffraction structure is further satisfied by the following formula: [0017] 093131353 Form No. A0101 5th Buy/Total 26 Page 0993367629-0 1337271 October 13, 1999 Correction Replacement Page [0018] Where f is the focal length of the aspherical diffraction structure, n2 is the refractive index at the focal point, λ is the incident wavelength in vacuum, seven is the wave number in vacuum, and X is the distance from any point on the surface of the aspherical diffraction structure to its central axis . [0019] The depth y(x) of the aspherical diffraction structure preferably satisfies the following formula: [0020] _^-

7〇)=——-—(V/2 + - / - ^ ^2 ) «1 - «2 < |^| < D I 2) [0021] 其中， λ2~ λ!n2 m=L 〇^7··· ，為非球面繞射結構之環帶數，為該非球面繞射結構之折射率，D係非球面繞射結構之口徑，7〇)=——-—(V/2 + - / - ^ ^2 ) «1 - «2 < |^| < DI 2) [0021] where λ2~ λ!n2 m=L 〇^ 7··· , the number of rings of the aspherical diffraction structure, the refractive index of the aspherical diffraction structure, and the diameter of the D-system aspherical diffraction structure,

[0022] 表示該非球面繞射結構每一個之環帶端點到所述非球 7：^ 面繞射結構中心軸之距離，滿足式： [0023] nl/2 〇 [0024] 所述繞射結構可向外凸出於該導光板，或者向内凹進於該導光板。 [0025] 所述出射面形成有至少一第二繞射結構，其可為非球面繞射結構。 093131353 表單編號Α0101 第6頁/共26頁 0993367629-0 1337271 099年10月13日修正替換頁 [0026] 所述導光板可為平板或楔型板。 [0027] 為解決上述第二個技術問題，本發明提供之技術方案係 :一種背光模組，包括一導光板與一位於其側面之光源，其中該導光板包括一入射面、一出射面與一設有若干微結構之反射面，該入射面形成有至少一個繞射結構。 [〇〇28] 相對于先前技術，本發明借鑒繞射光學結構之面型設計自由度大、對光束控制能力強之特點，採用直接於LGP之入射面製作繞射光學結構，使得整個結構之緊凑性高，並且可以根據光源大小與位置靈活設計結構之表面輪廓來調整傳統LED入射光束之入射角，提高光束之耦合效率，從而提高光能利用率，使得導光板具有高亮度與低能量損耗。另外，還能較好消除因為採用離散點光源（LED )造成靠近光源處，能量分佈不均之陰影效果。 [0029] 同時，本發明還可於LGP之出射面設計不同結構之繞射光學結構，從而達到對LGP出射角度與能量分佈之控制作用，進一步提高背光系統之能量利用率。【實施方式】 [0030] 下面將結合附圖對本發明作進一步之詳細說明。 [0031] 請一併參閱第七圖及第八圖，本發明所提供之一種平板型導光板50，包括一入射面51、一反射面52、一出射面 53及其其他幾個側面（未標示）。其中，入射面51形成於導光板50臨近光源70之侧面。出射面53形成於該導光板50之頂面。反射面52形成於導光板50之底面，其設有若干微結構521。 093131353 表單編號A0101 第7頁/共26頁 0993367629-0 H37271 099年10月13日梭正替換頁 [0032] &本實μ例中，該入射面51形成有—非球面繞射結構 '•玄非球面繞射結構512之相位延遲炉滿足下列關係式（1): [0033] _ ^ (^) = (/ - ^/72 + ) [0034][0022] representing the distance from the end point of each of the aspherical diffraction structures to the central axis of the aspherical diffraction structure, satisfying the formula: [0023] nl/2 〇 [0024] the diffraction The structure may protrude outwardly from the light guide plate or may be recessed inwardly into the light guide plate. [0025] The exit surface is formed with at least one second diffraction structure, which may be an aspherical diffraction structure. 093131353 Form No. Α0101 Page 6 of 26 0993367629-0 1337271 October 13, 2017 Correction Replacement Page [0026] The light guide plate may be a flat plate or a wedge plate. [0027] In order to solve the above second technical problem, the present invention provides a backlight module including a light guide plate and a light source on a side thereof, wherein the light guide plate includes an incident surface and an exit surface. A plurality of microstructured reflective surfaces are formed, the incident surface being formed with at least one diffraction structure. [〇〇28] Compared with the prior art, the present invention draws on the characteristics of large design freedom of the diffractive optical structure and strong controllability of the light beam, and adopts a direct optical structure directly formed on the incident surface of the LGP, so that the entire structure is The compactness is high, and the surface profile of the structure can be flexibly designed according to the size and position of the light source to adjust the incident angle of the incident beam of the conventional LED, thereby improving the coupling efficiency of the beam, thereby improving the utilization of the light energy, and the light guide plate has high brightness and low energy. loss. In addition, it is better to eliminate the shadow effect of uneven energy distribution due to the use of discrete point light sources (LEDs). [0029] In the meantime, the present invention can also design a diffractive optical structure of different structures on the exit surface of the LGP, thereby achieving the control effect on the LGP exit angle and energy distribution, and further improving the energy utilization rate of the backlight system. [Embodiment] The present invention will be further described in detail below with reference to the accompanying drawings. [0031] Please refer to the seventh and eighth figures together. The flat type light guide plate 50 provided by the present invention includes an incident surface 51, a reflecting surface 52, an emitting surface 53, and other sides thereof. Mark). The incident surface 51 is formed on a side of the light guide plate 50 adjacent to the light source 70. The exit surface 53 is formed on the top surface of the light guide plate 50. The reflecting surface 52 is formed on the bottom surface of the light guide plate 50, and is provided with a plurality of microstructures 521. 093131353 Form No. A0101 Page 7 of 26 0993367629-0 H37271 October 13th, 2008, the shuttle replacement page [0032] & In this example, the incident surface 51 is formed with an aspherical diffraction structure. The phase retarder of the mysterious aspherical diffraction structure 512 satisfies the following relation (1): [0033] _ ^ (^) = (/ - ^/72 + ) [0034]

其中f為該非球面繞射結構512之焦距，n2為焦點處之折射率’ λΜ空中人射波長乂，為真空中波數。焦距範圍為2〜10mm，根據情況，一般入光面之焦距比較短，而出光面之焦距比較長，這需要設計而得。χ 為该非球面繞射結構512表面上任意點到其中心軸之距離 (如X!，x2 ’ x3)，其取值根據LGP之外形尺寸而定，一般為—1 5mm〜+ 1 5mm。 [0035]同時’該非球面繞射結構512之深度y，即該非球面燒射 ® 結構512之環帶結構表面上之任意點到該非球面繞射結構 512所在基面之距離，一般在幾微米到幾百微米左右，其滿足下列關係式（2): [0036] __ y(x) = ~ J2 + - f - m λ2) <|^|<min(^+1>Z)/2) y _其中，；= ；!/% ’ w = 0，1，.··，*非球面繞射結 093131353 表單編號A0101 第8頁/共26頁 0993367629-0 1337271 099年10月13日修正替換頁Where f is the focal length of the aspherical diffraction structure 512, and n2 is the refractive index at the focus 'λ Μ Μ airborne wavelength 乂 , which is the number of waves in the vacuum. The focal length range is 2~10mm. According to the situation, the focal length of the light-incident surface is relatively short, and the focal length of the light-emitting surface is relatively long, which requires design. χ is the distance from any point on the surface of the aspherical diffraction structure 512 to its central axis (such as X!, x2 ' x3), and its value depends on the size of the LGP, which is generally -1 5mm~+ 1 5mm. [0035] At the same time, the depth y of the aspherical diffraction structure 512, that is, the distance from any point on the surface of the aspherical surface structure 512 to the base surface of the aspherical diffraction structure 512 is generally a few micrometers. A few hundred micrometers or so, which satisfies the following relation (2): [0036] __ y(x) = ~ J2 + - f - m λ2) <|^|<min(^+1>Z)/2) y _ where,;= ;!/% ' w = 0,1,.··,* aspherical diffractive knot 093131353 Form No. A0101 Page 8 of 26 0993367629-0 1337271 Correction replacement on October 13, 099 page

構512之環帶數’ 為該非球面繞射結構51 2之折射率，D 係非球面繞射結構51 2之口徑，即D = x ， * max [0038] 表示該非球面繞射結構51 2每一個之環帶端點到為該 ΛThe ring number ′ of the structure 512 is the refractive index of the aspherical diffraction structure 51 2 , and the aperture of the D-system aspherical diffraction structure 51 2 , that is, D = x , * max [0038] represents the aspherical diffraction structure 51 2 per One of the ring ends to the point

iW 非球面繞射結構512中心軸之距離，滿足下列關係式（3 [0039]The distance of the central axis of the iW aspherical diffraction structure 512 satisfies the following relationship (3 [0039]

2 ]1/2 ° [0040] 上述非球面繞射結構512之深度y與邊緣之尺寸一般2 ] 1/2 ° [0040] The depth y of the aspherical diffraction structure 512 and the size of the edge are generally

X3H 可應根據加工能力來選取。 [0041] 該非球面繞射結構512向外凸出於該導光板50。需指出的係，為了實際加工方便，可以將曲面面型之非球面繞射結構512用直線面型來代替，這樣在不影響性能之情況下更便於加工。The X3H should be selected based on processing capabilities. [0041] The aspherical diffraction structure 512 protrudes outward from the light guide plate 50. It should be pointed out that for the convenience of actual processing, the aspherical diffraction structure 512 of the curved surface type can be replaced by a straight surface type, which is more convenient to process without affecting performance.

[0042] 本實施例為了綜合利用各個離散光源70之功能，於整個入射面51上做成一個非球面繞射結構512。當然，還可以根據光源70之數目，於入射面51上形成分別與各光源70 對應之獨立之若干繞射結構，不必限於此實施例。 [0043] 請參閱第九圖，其為當於LGP入光面之中心位置放置一個 LED作為光源時，LGP出射光場強度分佈值，其中第九A圖為入射面無繞射結構之情況，第九B圖為入射面有本發明之繞射結構之情況。其中，實驗所用LGP之出射面沒有繞射結構，其具體參數為：f = 3mm，X在一3mm〜+ 3mm， 093131353 表單編號A0101 第9頁/共26頁 0993367629-0 1337271 099年10月13日修正替换頁深度y最大值為〇.41mm ’ 1^ = 1.49 ’ n2=l，波長為可見光0. 55um。實驗結果表明入射面之繞射結構對光場之調製效果明顯。 [0044] 此外，在本實施例中，該導光板50之出射面53上也形成有一第二非球面繞射結構532，其繞射面型之相位延遲同樣滿足上述關係式（1)，其具體參數應根據實際情況加以設計，一般與入射面51之非球面繞射結構512之參數不同。兩者具有相同深度，也可根據情況將其設計為不同 _ 深度。 [0045] 另外，該第二非球面繞射結構532呈一維柱面形狀，由臨近入射面一端延伸至與其相對之另一端。值得注意的係，其也可以設計成二維彎曲形狀r該第二非球面繞射結構532向外凸出於該導光板50。可以選擇的係，其也可以向内凹進於該導光板50。 [0046] 本發明之導光板50係由合成樹脂材料製成之平板型結構 • ，其反射面可以為V型結構或者為傳統圓形小點等微結構 [0047] 光源70為點光源，如發光二極管。當然，也可選用線光源，例如冷陰極管。 [0048] 請參閱第十圖，為驗證繞射結構對於消除陰影現象之作用，計算有繞射結構與沒有繞射結構兩種導光板之光場分佈，光源為3個相同之LED。其中有繞射結構之導光板，其繞射結構之具體參數為： [0049] ( 1 )入光面，f = 3mm，X在一1 5mm〜+ 1 5mm，深度y最 093131353 表單編號A0101 第10頁/共26頁 0993367629-0 1.337271 大值為〇.8841πππ，η =1.49，rig: 〇.55um ; 099年10月13日修正波長為可見光 [0050] [0051] [0052] [0053] (2)出光面 ’ f = l〇mm，X在—15mm〜+ 15mm，深度y最大值為0·6316_，η =1.49，n =l，波長為可見光 1 ^〇.55um。 [0054] 093131353 結果表明，繞射結構對光場之調製能力明顯。請參閱第十一圖’本發明所提供之另一平板型導光板6〇與前一實施例中之平板型導光板50相比，其主要不同在於’入射面61形成之非球面繞射結構612向内凹進於導光板60。請參閱第十二圖，採用導光板5〇之背光模組8〇，包括導光板50、位於其側面之光源70、位於其下方之反射板82 、以及依次位於其上方之擴散片84以及增亮片86等光學膜片。其中反射片82係將未被散射之光線再導入導光板 5〇中，擴散片84使光線形成漫射而均勻擴散，消除導光板50上微結構521形成之亮區，增亮片86起到會聚光線，提高亮度之作用。請參閱第十三圖’上述繞射結構同樣可以應用於棋型導光板中。在本實施财，本發明提供之Μ導光板90，包括-入射面91、-反射面92、_出射面93及其其他幾個側面（未標示）。其中，該人射面91形成有-非球面繞射結構912，其同樣滿足上述關係式（1)〜（3)。需注意的係、’本發明還可採用其他形狀之繞射結構，並不僅限於非球面型繞射結構。表單編號Α0101 第11頁/共26頁 0993367629-0 [0055] 1337271 099年10月13日修正替換頁 [0056] 本發明借鑒繞射光學結構之面型設計自由度大、對光束控制能力強之特點，採用直接於LGP之入射面製作繞射光學結構，使得整個結構之緊湊性高，並且可以根據光源大小與位置靈活設計結構之表面輪廓來調整傳統LED入射光束之入射角，提高光束之耦合效率，從而提高光能利用率，使得導光板具有高亮度與低能量損耗。另外，還能較好消除由於採用離散點光源（LED)造成之靠近光源處，能量分佈不均之陰影效果。 [0057] 同時，本發明還可於LGP之出射面設計不同結構之繞射光學結構，從而達到對LGP出射角度與能量分佈之控制作用，進一步提高背光系統之能量利用率。 [0058] 另外，本領域技術人員還可在本發明精神内做其他變化，如在導光板之反射面上設置增反膜以替代背光模組中之反射板等設計。當然，這些依據本發明精神所做之變化，都應包含在本發明所要求保護之範圍内。【圖式簡單說明】 [0059] 第一圖係傳統之光源與導光板結合之結構示意圖； [0060] 第二圖係先前技術之第6, 421，104號美國專利所揭示之背光系統之結構示意圖； [0061] 第三圖係先前技術之特開平1 0-19931 6曰本專利申請所揭示之背光系統之結構示意圖； [0062] 第四圖係先前技術之第2003021 481 8號美國專利申請所揭示之背光系統之結構示意圖； 0993367629-0 [0063] 第五圖係第四圖中V部分之局部放大圖； 093131353 表單編號A0101 第12頁/共26頁 1337271 r_ 099年10月13日修正替換頁 [0064] 第六圖係先前技術之第6, 636, 283號美國專利所揭示之背光系統之結構示意圖； [0065] 第七圖係本發明提供之平板型導光板之立體示意圖； [0〇66]第八圖係本發明提供之平板型導光板之平面示意圖； [0067] 第九A圖係入射面無繞射結構之導光板之光場強度分佈圖 , ’第九B圖係入射面有繞射結構之導光板之光場強度分佈 TSI · 圍， [0068] 第十A圖係入射面無繞射結構之導光板之光場分佈圖，第丨十B圖係入射面有繞射結構之導光板之光場分佈圖； [0069] 第十一圖係本發明提供之另一平板型導光板之結構示意 [0070]第十二圖係採用本發明提供之平板型導光板之背光模組之結構示意圖 [00Ή]第十三圖係本發明提供之楔型導光板之立體示意圖。【主要元件符號說明】 [0072] 導光板 50入射面51 [0073] 非球面繞射結構512反射面52 [0074] 微結構521出射面53 [0075] 第二非球面繞射結構532導光板 60 [0076] 入射面 61非球面繞射結構612 [0077] 光源70背光模組80 0993367629-0 093131353 表單編號A0101 第13頁/共26頁 1337271 [0078] 反射板 82 擴散片84 [0079] 增亮片 86 楔型導光板90 ' [0080] 入射面 91 非球面繞射結構912 [0081] 反射面 92 出射面9 3 093131353 表單編號A0101 第14頁/共26頁 099年10月13日按正替换頁 0993367629-0[0042] In the present embodiment, in order to comprehensively utilize the functions of the discrete light sources 70, an aspherical diffraction structure 512 is formed on the entire incident surface 51. Of course, a plurality of independent diffraction structures respectively corresponding to the respective light sources 70 may be formed on the incident surface 51 according to the number of the light sources 70, and are not necessarily limited to this embodiment. [0043] Please refer to the ninth figure, which is a distribution value of the intensity field of the LGP exiting light when an LED is placed at the center of the light incident surface of the LGP, wherein the ninth A is a diffraction-free structure of the incident surface. Figure IXB shows the case where the incident surface has the diffraction structure of the present invention. Among them, the exit surface of the LGP used in the experiment has no diffraction structure, and its specific parameters are: f = 3mm, X is 3mm~+ 3mm, 093131353 Form No. A0101 Page 9 / Total 26 Page 0993367629-0 1337271 099 October 13 The maximum value of the depth of the replacement page is 〇.41mm ' 1^ = 1.49 ' n2=l, and the wavelength is visible light. The experimental results show that the diffraction structure of the incident surface has a significant effect on the modulation of the light field. In addition, in the embodiment, a second aspherical diffraction structure 532 is also formed on the exit surface 53 of the light guide plate 50, and the phase delay of the diffraction surface pattern also satisfies the above relationship (1). The specific parameters should be designed according to the actual situation, and generally different from the parameters of the aspherical diffraction structure 512 of the incident surface 51. Both have the same depth and can be designed to be different _ depth depending on the situation. In addition, the second aspherical diffraction structure 532 has a one-dimensional cylindrical shape extending from one end of the near-incident surface to the other end opposite thereto. It is also worth noting that it can also be designed as a two-dimensional curved shape r. The second aspherical diffraction structure 532 protrudes outwardly from the light guide plate 50. A system can be selected which can also be recessed inwardly into the light guide plate 50. [0046] The light guide plate 50 of the present invention is a flat type structure made of a synthetic resin material, and the reflective surface thereof may be a V-shaped structure or a micro structure such as a conventional circular dot [0047] The light source 70 is a point light source, such as led. Of course, a line source such as a cold cathode tube can also be used. [0048] Referring to the tenth figure, in order to verify the effect of the diffraction structure on eliminating the shadow phenomenon, the light field distribution of the light guide plates having the diffraction structure and the non-diffraction structure is calculated, and the light source is three identical LEDs. Among them, there is a diffractive structure light guide plate, and the specific parameters of the diffraction structure are: [0049] (1) light entrance surface, f = 3mm, X is at 1 5mm~+1 5mm, depth y is the most 093131353 Form No. A0101 10 pages/total 26 pages 0993367629-0 1.337271 The large value is 884.8841πππ, η =1.49, rig: 〇.55um; the corrected wavelength is visible light on October 13, 099 [0050] [0052] [0053] 2) The light-emitting surface 'f = l〇mm, X is -15mm~+ 15mm, the maximum depth y is 0·6316_, η = 1.49, n = l, and the wavelength is visible light 1 ^ 〇 .55um. [0054] 093131353 The results show that the diffraction structure has a significant ability to modulate the light field. Referring to FIG. 11 'the other flat type light guide plate 6 provided by the present invention is different from the flat type light guide plate 50 of the previous embodiment, and the main difference is that the aspherical diffraction structure formed by the incident surface 61 The 612 is recessed inwardly into the light guide plate 60. Referring to FIG. 12, a backlight module 8A using a light guide plate 5b includes a light guide plate 50, a light source 70 on a side thereof, a reflection plate 82 located therebelow, and a diffusion sheet 84 sequentially positioned thereon. Optical film such as sequins 86. The reflection sheet 82 re-introduces the unscattered light into the light guide plate 5, and the diffusion sheet 84 diffuses the light to uniformly diffuse, eliminating the bright region formed by the microstructure 521 on the light guide plate 50, and the brightness enhancement sheet 86 converges. Light, the effect of increasing brightness. Please refer to the thirteenth diagram. The above diffraction structure can also be applied to a chess type light guide plate. In the present invention, the present invention provides a light guide plate 90 including an entrance surface 91, a reflection surface 92, an exit surface 93, and other sides thereof (not shown). Among them, the human face 91 is formed with an aspherical diffraction structure 912 which also satisfies the above relations (1) to (3). It is to be noted that the present invention can also employ other shapes of diffraction structures, and is not limited to aspherical diffraction structures. Form No. 1010101 Page 11/Total 26 Page 0993367629-0 [0055] 1337271 Modified on October 13, 099 [0056] The present invention draws on the design of the diffractive optical structure with a large degree of freedom in design and strong control of the light beam. The feature is that the diffractive optical structure is directly formed on the incident surface of the LGP, so that the whole structure is compact, and the surface contour of the structure can be flexibly designed according to the size and position of the light source to adjust the incident angle of the incident beam of the conventional LED, thereby improving the coupling of the beam. Efficiency, thereby increasing the utilization of light energy, makes the light guide plate have high brightness and low energy loss. In addition, it is better to eliminate the shadow effect of uneven energy distribution due to the use of discrete point sources (LEDs) close to the source. [0057] At the same time, the invention can also design a diffractive optical structure of different structures on the exit surface of the LGP, thereby achieving the control effect on the LGP emission angle and the energy distribution, and further improving the energy utilization rate of the backlight system. In addition, those skilled in the art can also make other changes in the spirit of the present invention, such as providing an anti-reflection film on the reflective surface of the light guide plate instead of the reflective plate in the backlight module. Of course, these changes in accordance with the spirit of the invention are intended to be included within the scope of the invention as claimed. BRIEF DESCRIPTION OF THE DRAWINGS [0059] The first figure is a structural diagram of a combination of a conventional light source and a light guide plate; [0060] The second figure is a structure of a backlight system disclosed in U.S. Patent No. 6,421,104. BRIEF DESCRIPTION OF THE DRAWINGS [0061] FIG. 3 is a schematic view showing the structure of a backlight system disclosed in the present patent application; [0062] FIG. 4 is a prior art US Patent Application No. 2003021 481 8 Schematic diagram of the disclosed backlight system; 0993367629-0 [0063] The fifth figure is a partial enlarged view of the V portion in the fourth figure; 093131353 Form No. A0101 Page 12 of 26 1337271 r_ October 13, 1999 amendment [0064] FIG. 6 is a schematic view showing the structure of a backlight system disclosed in US Pat. No. 6,636,283; [0065] FIG. 7 is a perspective view of a flat type light guide plate provided by the present invention; 0〇66] FIG. 8 is a plan view of a flat-type light guide plate provided by the present invention; [0067] FIG. 9A is a light field intensity distribution diagram of a light guide plate having an incident surface without a diffraction structure, and 'Nineth B diagram The incident surface has a diffraction structure The light field intensity distribution of the light guide plate TSI · circumference, [0068] The tenth A picture is the light field distribution diagram of the light guide plate with no diffraction structure on the incident surface, and the tenth B picture is the light guide plate with the diffraction structure on the incident surface Light field distribution map; [0069] FIG. 11 is a schematic structural diagram of another flat type light guide plate provided by the present invention. [0070] FIG. 12 is a schematic structural view of a backlight module using the flat type light guide plate provided by the present invention. [00Ή] FIG. 13 is a perspective view of a wedge-shaped light guide plate provided by the present invention. [Main component symbol description] [0072] Light guide plate 50 incident surface 51 [0073] Aspherical diffraction structure 512 reflective surface 52 [0074] Microstructure 521 exit surface 53 [0075] Second aspherical diffraction structure 532 light guide plate 60 Injecting surface 61 aspherical diffraction structure 612 [0077] Light source 70 backlight module 80 0993367629-0 093131353 Form No. A0101 Page 13 / Total 26 pages 13327271 [0078] Reflector 82 Diffuser 84 [0079] Brightening sheet 86 Wedge Light Guide 90 ' [0080] Incidence Surface 91 Aspherical Diffraction Structure 912 [0081] Reflecting Surface 92 Exit Surface 9 3 093131353 Form No. A0101 Page 14 of 26 October 13th, 9999 Pressing the Replacement Page 0993367629-0

Claims

七、申請專利範圍： 099年 1〇月 13日種導光板，包括-人射面出射面及—設有若干微結構之反射面，其改進在於，該人射面形成有至少—個非球面繞射結構，所述非球面繞射結構之深度心），即該非球面繞射結構之環帶結縣面上之任意關該非球面繞射結構所在基面之距離，其滿足下式： y(^)Seven, the scope of application for patents: 099 January 1st, 13th kind of light guide plate, including - human face exit surface and - with a number of microstructured reflective surface, the improvement is that the person's face is formed with at least - aspheric The diffraction structure, the depth of the aspherical diffraction structure, that is, the distance between the abutment surface of the aspherical diffraction structure and the base surface of the aspherical diffraction structure, which satisfies the following formula: y( ^)

士 = /Ϊ /乃2，W = 0,1，…為非球面繞射結構之環帶數，11丨為該非球面繞射結構之折射率，D係非球面繞射結構之口徑， X表示非球面繞射結構每一個之環帶端點到豆中心軸之 w '、± = Ϊ / is 2, W = 0, 1, ... is the number of rings of the aspherical diffraction structure, 11 丨 is the refractive index of the aspherical diffraction structure, and the diameter of the D-type aspherical diffraction structure, X is The end point of each aspherical diffraction structure to the center axis of the bean w',

距離，滿足式： 2mf^ + {m\) 2 1/2 如申請專利範圍第1項所述之導光板，其中，所述非球面繞射結構之相位延遲滿足下式： 093131353 其中f為該非球面繞射結構之焦距，η2為焦點處之折射率表軍編珑Α0101 第15頁/共26頁 0993367629-0 1337271 099年10月13日核正替换頁，λ為真空中入射波長 = 2πί λ ，為真空中波數，X為該非球面繞射結構表面上任意點到非球面繞射結構中心軸之距離。如申請專利範圍第1項所述之導光板，其中，所述繞射結構向外凸出於該導光板。如申請專利範圍第1項所述之導光板，其令，所述繞射結構向内凹進於該導光板。The light guide plate of claim 1, wherein the phase retardation of the aspherical diffraction structure satisfies the following formula: 093131353 where f is the non-availability: 2mf^ + {m\) 2 1/2 The focal length of the spherical diffraction structure, η2 is the refractive index at the focus of the table. 0101 Page 15 of 26 Page 0993367629-0 1337271 October 13th, 1999, the replacement page, λ is the incident wavelength in vacuum = 2πί λ Is the wave number in the vacuum, and X is the distance from any point on the surface of the aspherical diffraction structure to the central axis of the aspherical diffraction structure. The light guide plate of claim 1, wherein the diffraction structure protrudes outward from the light guide plate. The light guide plate of claim 1, wherein the diffraction structure is recessed inwardly of the light guide plate.

如申請專利範圍第1項所述之導光板，其中，所述出射面形成有至少一第二繞射結構。如申請專利範圍第5項所述之導光板，其中，所述第二繞射結構為非球面繞射結構。如申請專利範圍第1所述之導光板，其中，所述導光板為平板或楔型板。The light guide plate of claim 1, wherein the exit surface is formed with at least one second diffraction structure. The light guide plate of claim 5, wherein the second diffraction structure is an aspherical diffraction structure. The light guide plate of claim 1, wherein the light guide plate is a flat plate or a wedge plate.

一種背光模組，包括一導光板及一位於其側面之光源，其中該導光板包括一入射面、一出射面及一設有若干微結構之反射面，其特徵在於，該入射面形成有至少一個非球面繞射結構，所述非球面繞射結構之深度y(x)，即該非球面繞射結構之環帶結構表面上之任意點到該非球面繞射結構所在基面之距離，其滿足下式： yM = ———(V/2 + - f ~mA2) «ι - < |χ| < min(^+1, D / 2) 其中，為非球面繞射結 093131353 表單編號A0101 第16頁/共26頁 0993367629-0 1337271 099年10月13日後正餘頁構之環帶數，\為該非球面繞射結構之折射率，_非球面繞射結構之口徑，、表示非球面繞射結構每-個之環帶端點到其中心袖之距離，滿足式：〜=[2彷/名 + 〇«々)2]1/2。 9.如申請專利範圍第8項所述之背光模組，其中，所述非球面繞射結構之相位延遲炉滿足下式：屮（））=允〇«2(/ -、/ 其中f為該非球面繞射結構之焦距、為焦點處之折射率，λ為真空中入射波長， **…丄為真空中波數 ’ X為該非球面繞射結構表面上&意點到非球面繞射結構中心軸之距離。A backlight module includes a light guide plate and a light source on a side thereof, wherein the light guide plate includes an incident surface, an exit surface, and a reflective surface provided with a plurality of microstructures, wherein the incident surface is formed with at least An aspherical diffraction structure, the depth y(x) of the aspherical diffraction structure, that is, the distance from any point on the surface of the annulus structure of the aspherical diffraction structure to the base surface of the aspherical diffraction structure, which satisfies The following formula: yM = ———(V/2 + - f ~mA2) «ι - < |χ| < min(^+1, D / 2) where is the aspherical diffraction knot 093131353 Form No. A0101 Page 16 of 26 0993367629-0 1337271 The number of rings in the normal page after October 13, 099, \ is the refractive index of the aspherical diffraction structure, the aperture of the aspherical diffraction structure, and the aspheric surface The distance from the end of each ring of the diffraction structure to its center sleeve is satisfied: ~=[2 imitation/name+ 〇«々) 2]1/2. 9. The backlight module of claim 8, wherein the phase retarder of the aspherical diffraction structure satisfies the following formula: 屮())=allow 〇«2(/ -, / where f is The focal length of the aspherical diffraction structure is the refractive index at the focus, λ is the incident wavelength in vacuum, **...丄 is the wave number in the vacuum' X is the surface of the aspherical diffraction structure & point to aspherical diffraction The distance from the center axis of the structure.

10.如申請專利範圍第8項所述之背光模組，其中，所述繞射結構向外凸出於該導光板。 11 .如申請專利範圍第8項所述之背光模組，其中，所述繞射結構向内凹進於該導光板。 12 ,如申請專利範圍第8項所述之背光模組，其中’所述出射面形成有至少一第二繞射結構。 13 .如申請專利範圍第12項所述之背光模組，其中，所述第_ 繞射結構為非球面繞射結構。 093131353 如申請專利範圍第8項所述之背光模組，其中，表單編號Α0101 第17頁/共26頁所述導光 0993367629-0 14 1337271 099年10月13日梭正替換頁板為平板或楔型板。10. The backlight module of claim 8, wherein the diffraction structure protrudes outwardly from the light guide plate. The backlight module of claim 8, wherein the diffraction structure is recessed inwardly of the light guide plate. The backlight module of claim 8, wherein the exit surface is formed with at least one second diffraction structure. The backlight module of claim 12, wherein the first ray diffraction structure is an aspherical diffraction structure. 093131353 The backlight module according to claim 8 of the patent application, wherein the form number Α0101, page 17 / total 26 pages, the light guide 0993367629-0 14 1337271, October 13, 1999, the shuttle is replacing the page board as a flat plate or Wedge plate.

093131353 表單編號A0101 第18頁/共26頁 0993367629-0093131353 Form No. A0101 Page 18 of 26 0993367629-0