201101128 六、發明說明： 【發明所屬之技術領域】 [0001] 本發明涉及一種輸入裝置，尤其涉及一種觸控式輸入裝 置。 【先前技術】201101128 VI. Description of the Invention: [Technical Field] The present invention relates to an input device, and more particularly to a touch input device. [Prior Art]
[0002] 隨著社會之發展及科技之進步，介面更人性化，輸入更 簡便之帶有觸摸屏被廣泛地應用於個人電腦、移動電話 、電視、攝影機、測量儀器等顯示器上。請參見文獻A novel gestural input device for virtual reali ty » Maggioni, C. ;V i rtual Reality Annual International Symposium, 1993., 1993 IEEE18-22 Sept. 1993 Page(s):118 - 124。 [0003] 觸控屏根據所用之介質以及工作原理，可分為電阻式、 電容式、紅外線式及表面聲波式多種。目前較為常用之 觸控輸入裝置為電阻式及電容式兩種，但其均需要於面 板上設置感應之電路，且無法實現多點觸控感應。此外 ，此類觸控輸入裝置易受環境電場之影響，進而降低感 〇 應之準確度。 【發明内容】 [0004] 有鑑於此，提供一種能夠實現多點觸控且具有高之感應 之準確度之觸控式輸入裝置實屬必要。 [0005] 一種觸控式輸入裝置，其包括一個紅外光源模組、一個 第一偏振片、一個應力感測片、至少一個第二偏振片、 至少一個紅外攝像頭及一個圖像處理器，所述紅外光源 模組、第一偏振片及應力感測片依次相鄰設置，所述紅 098120178 表單編號A0101 第4頁/共17頁 0982034299-0 201101128 ο [0006] ❹ [0007] 外光源模組用於提供紅外光，所述第_偏振片用於將所 述、’外光轉化為第一偏振光，所述應力感測片設置於第 偏振片與第二偏振片之間，用於於被觸碰時於其内部 產生應力’從而使所述第—偏振光經過應力感測片時發 生又折射後出射’所述第二偏振片之偏振化方向與第一 偏振片之偏振化方向相互垂直，用於將應力感測片出射 之光線轉化為第二偏振光’所述紅外攝像翻於藉由第 偏振片獲取應力感測片由於應力產生之干涉條紋圖像 所述圖像處理器與紅外攝像頭相連接，用於接收並對 紅外攝像頭獲取之圖像進行處理從而判定應力感測片被 觸碰之位置及觸碰之軌跡。 本技術方案提供之觸控式輪人裝置，採用第—偏振片將 、’外光源模組產生之紅外光轉化為偏振光，該偏振光經 過由於施加外力而具有應力之應力感測片產生之雙折射 現象’紅外攝像頭透過具有與第―偏片振化方向垂直之 第二偏振片得到影像經過影像處理器進行處理，從而可 知到觸碰物體觸碰應力感測片之俾置及軌跡，從而實現 觸控式輸入。因此，本技術方案提供之觸控式輸入裝置 能夠準確地感應觸碰之位置及觸碰之軌跡，並且能夠實 現多點觸控。 【實施方式】 下面將結合複數實施例及複數附圖，對本技術方案提供 之觸控式輸入裝置作進一步之詳細說明。 請一併參閱圖1及圖2 ’本技術方案第一實施例提供一種 觸控式輸入裝置1〇〇，其包括一紅外光源模組11〇、一第 098120178 表單編號A0101 第5頁/共17頁 0982034299-0 [0008] 201101128 一偏振片1 2 0、一應力感測片1 3 0、二紅外攝像頭14 〇、 二第二偏振片150及一圖像處理器160。 [0009] [0010] [0011] 紅外光源模組110用於提供紅外光。本實施例中，紅外光 源模組11〇包括複數紅外光源ill及一導光板112。複數 紅外光源111用於發射紅外光，並使紅外光相導光板丨i 2 内入射，導光板112用於將紅外光源11丨入射之紅外光線 均勻從導光板112出射。本實施例中，紅外光源模级u〇 包括四紅外光源111。紅外光源111可為紅外發光二級管 或紅外鐳射光源。 本實施例中，導光板112為長方體，其具有—出光面1121 、一與出光面1121相對之底面1122及—連接於出光面 1121及底面1122之間之入光面1123。於底面1122上設 置有複數網點（圖未示），用於將紅外光源lu入射至導 光板112内之廣進行擴散，使得紅外光線經過出光面Η。 均勻地射出導光板112。四個紅外束源lu平行於入光面 1123設置。每個紅外光源i U之出光面與導光板ιΐ2之入 光面1123相對。當然，導卷板112多形狀並不限於長方體 ，其亦可為圓柱體、圓臺形或多棱柱形等其他形狀。 當然’紅外光源模組110不限於本實施例中之結構，其亦 可包括複數陣列排部之複數紅外光源，僅f使每個紅外 光源之出光面與第一偏振片12〇相對即可。 第-偏振㈣紅外光源·11{)提供之紅外光線 轉換為紅外偏振光線。第-偏振片m設置於紅外光源模 組no與應力感測片130之間。第—偏振片12〇與導光板 098120178 表單編號A0101 第6頁/共17頁 0982034299-0 [0012] 201101128 112之出光面1121相對，用於將由出光面1121出射之紅 外光轉換為偏振光線。本實施例中，第一偏振片120為長 方形片狀，其為線偏振片。優選地，第一偏振片120與出 光面1121同軸設置。 [0013] ❹ Ο 應力感測片130設置於第一偏振片120遠離紅外光源模組 110之一側。本實施例中，應力感測片130為長方形片狀 ，其具有觸碰面131及於觸碰面相對之背面132，背面 132與第一偏振片120相對。應力感測片130由能夠由於 外加力之作用而產生内應力之透光材料製成，如其可由 具有上述性能之各種塑膠或者液晶等材料製成。當觸碰 物體到觸碰面131時，觸碰施加於觸碰面131之壓力使得 應力感測片130内部對應觸碰之位置產生應力。當觸碰應 力感測片130對應之位置内部產生應力時，當光線經過上 述位置時，光線便會發生雙折射現象。此係因為應力感 測片13 0内之應力會產生一定程度之各向異性，從而產生 雙折射。亦即，這種具有應力之透明介質中〇光及e光產 生之光程差不為零，〇光及e光產生之光程差與應力分佈 有關。如果將上述介質做成片狀插於兩偏振片之間，不 同之位置因〇光及e光產生之光程差不同而引起〇光、e光 間不同之位相差，藉由與第一偏振片120偏振化方向垂直 之偏振片便可觀測到干涉條紋。應力越集中之地方，各 向異性越強，干涉條紋越細密。 紅外攝像頭140與碰觸面131相對。本實施例中，觸控式 輸入裝置100包括兩個紅外攝像頭140。該兩紅外攝像頭 設置於該碰觸面131同一邊之兩個頂角處之上方。兩個紅 098120178 表單編號A0101 第7頁/共17頁 0982034299-0 [0014] 201101128 外攝像頭140之視場141重疊之區域覆蓋整個觸碰面131 。兩個紅外攝像頭140與碰觸面131間隔一定距離，該距 離由碰觸面131之面積大小決定。碰觸面131之面積越大 ，該距離越遠。紅外攝像頭140不局限於本實施例中之兩 個，可為多於兩個，其數量可根據碰觸面131之面積大小 及紅外攝像頭140之視場大小來設定。碰觸面131之面積 越大，所需要之紅外攝像頭140之數量越多；紅外攝像頭 140之視場越小，所需要之紅外攝像頭140之數量越多。 紅外攝像頭140優選為廣角式紅外攝像頭，其視場角範圍 ^ ?) 於90到120度之間。 [0015] 第二偏振片150設置於碰觸面131與紅外攝像頭140之間 。第二偏振片150用於使得從應力感測片130入射至其之 光線進行偏振化，使得上述光線轉化為與第二偏振片150 偏振化方向相同之光線。本實施例中，觸控式輸入裝置 100包括兩第二偏振片150，每個第二偏振片150對應安 裝於一紅外攝像頭140之物側。第二偏振片150與第一偏 振片120之偏振角度相互垂直。 y [0016] 可理解，第二偏振片150亦可封裝於每個紅外攝像頭140 中〇 [0017] 紅外光源模組110出射之紅外光線經過第一偏振片120轉 化為與第一偏振片120偏振化方向相同之偏振光，當該偏 振光經過沒有產生應力之應力感測片130時，該偏振光不 會發生雙折射。第一偏振片120與第二偏振片150之偏振 化方向相互垂直，紅外攝像頭140藉由第二偏振片150不 會呈現形成有干涉條紋之影像。然而，紅外光源模組110 098120178 表單編號A0101 第8頁/共17頁 0982034299-0 201101128 出射之紅外光線經過第一偏振片120轉化為與第一偏振片 120偏振化方向相同之偏振光後，當該偏振光經過由於觸 碰而產生應力之應力感測片130時，該偏振光於產生應力 對應之位置發生雙折射，因為第一偏振片120與第二偏振 片150之偏振化方向相互垂直，紅外攝像頭140藉由第二 偏振片150會於產生應力對應之位置形成有干涉條紋之影 像。 [0018] 圖像處理器160與兩紅外攝像頭150相連接。圖像處理器 ^ 160用於接收每個紅外攝像頭150所獲得之圖像訊號，並 對該圖像訊號進行處理。圖像處理器160將兩個紅外攝像 頭150所獲得之影像進行處理，即可分別得到該位置於觸 碰面131上具體之位置；並且，觸碰之位置發生移動時， 圖像處理器160根據與其連接之紅外攝像頭150所獲得之 圖像訊號，判斷觸碰之移動之軌跡。可理解之係，該觸 控式輸入裝置100亦可用來同時識別複數觸控位置及觸碰 之軌跡。 〇 [0019] 請參一併參閱圖3及圖4，本技術方案第二實施例提供之 一種觸控式輸入裝置200，其結構與第一實施例提供之觸 控式輸入裝置100結構相近，不同之處為，觸控式輸入裝 置200之紅外光源模組210具有一反射板213並具有兩入 光面2123。另外，觸控式輸入裝置20 0僅包括一紅外攝像 頭240及一第二偏振片250。反射板213設置於導光板212 之底面2122，用於防止光線從底面2122出射，可提高光 之利用率。導光板212具有兩個連接於出光面2121及底面 2122之間之入光面2123，兩入光面2123相對。平行於每 098120178 表單編號A0101 第9頁/共17頁 0982034299-0 201101128 個入光面112 3均設置有四紅外光源21!，以提高導光板 212之出光亮度。一個紅外攝像頭24〇設置於應力感測片 230之觸碰面231之中心軸線上，一第二偏振片25〇設置 於應力感測片230於紅外攝像頭24〇之間。紅外攝像頭 240之視場覆蓋整個觸碰面mi。 [0020] 本技術方案提供之觸控式輸入裝置，採用第一偏振片將 紅外光源模組產生之紅外光轉化為偏振光，該偏振光經 過由於施加外力而具有應力之應力感測片產生之雙折射 現象，紅外攝像頭透過具有與第一偏片振化方向垂直之 第二偏振片得到影像經過影像處理器進行處理，從而可 得到觸碰物體觸碰應力感測片之位置及軌跡，從而實現 觸控式輸入。因此’本技術方案提供之觸控式輸入裝置 能夠準確地感應觸碰之位置及觸碰之軌跡，並且能夠實 現多點觸控。 [0021] 綜上所述，本發明確已符合發明專利之要件，遂依法提 . ... ： ·. 出專利申請。惟’以上所述者僅為本發明之較佳實施方 式，自不能以此限制本案之申請專利範圍。舉凡熟悉本 案技藝之人士援依本發明之精神所作之等效修飾或變化 ，皆應涵蓋於以下申請專利範圍内。 【圖式簡單說明】 [0022] 圖1係本技術方案第一實施例提供之觸控式輸入裝置之剖 視示意圖。 [0023] 圖2係圖1中觸控式輸入裝置之俯視示意圖。 [0024] 圖3係本技術方案第二實施例提供之觸控式輸入裝置之剖 098120178 表單編號A0101 第10頁/共17頁 0982034299-0 201101128 視示意圖。 [0025] Ο ο 098120178 圖4係圖3中觸控式輸入裝置之俯視示意圖。 【主要元件符號說明】 [0026] 觸控式輸入裝置 100 ' 200 紅外光源模組 110 、 210 紅外光源 111 、 211 導光板 112 、 212 出光面 1121 、 2121 底面 1122 、 2122 入光面 1123 、 2123 第一偏振片 120 應力感測片 130 、 230 觸碰面 131 、 231 背面 132 紅外攝像頭 140 ' 240 視場 141 第二偏振片 150 、 250 圖像處理器 160 反射板 213 表單編號Α0101 第11頁/共17頁 0982034299-0[0002] With the development of society and the advancement of technology, the interface is more user-friendly, and the input with a simple touch screen is widely used in displays such as personal computers, mobile phones, televisions, cameras, measuring instruments, and the like. See A novel gestural input device for virtual realty ty » Maggioni, C.; V i rtual Reality Annual International Symposium, 1993., 1993 IEEE 18-22 Sept. 1993 Page(s): 118-124. [0003] Touch screens can be classified into resistive, capacitive, infrared, and surface acoustic wave types depending on the medium used and the working principle. Currently, the touch input devices are commonly used in both resistive and capacitive modes, but they all need to be provided with an inductive circuit on the panel, and multi-touch sensing cannot be realized. In addition, such touch input devices are susceptible to environmental electric fields, which in turn reduces the accuracy of the sensory response. SUMMARY OF THE INVENTION [0004] In view of the above, it is necessary to provide a touch input device capable of achieving multi-touch and having high accuracy of sensing. [0005] A touch input device includes an infrared light source module, a first polarizing plate, a stress sensing sheet, at least one second polarizing plate, at least one infrared camera, and an image processor. The infrared light source module, the first polarizing plate and the stress sensing sheet are arranged adjacent to each other in sequence, the red 098120178, the form number A0101, the fourth page, the total number of pages, the number of pages, the number of pages, the number of the Providing infrared light, the first polarizer is for converting the external light into a first polarized light, and the stress sensing sheet is disposed between the polarizer and the second polarizer for being used by When the touch generates stress in the interior thereof, so that the first polarized light passes through the stress sensing sheet, and then refracts and then exits. The polarizing direction of the second polarizing plate is perpendicular to the polarization direction of the first polarizing plate. For converting the light emitted from the stress sensing sheet into the second polarized light. The infrared imaging is turned over by the first polarizing plate to obtain the interference sensing sheet due to stress. The image processor and the infrared image. Camera The head is connected for receiving and processing the image acquired by the infrared camera to determine the position where the stress sensor is touched and the track of the touch. The touch wheel device provided by the technical solution converts the infrared light generated by the external light source module into polarized light by using a first polarizing plate, and the polarized light is generated by a stress sensing piece having stress due to application of an external force. The phenomenon of birefringence 'infrared camera is processed by the image processor through the second polarizer having the direction perpendicular to the oscillating direction of the first yoke, so that the touch object touches the sway and the trajectory of the stress sensing piece, thereby Implement touch input. Therefore, the touch input device provided by the technical solution can accurately sense the position of the touch and the track of the touch, and can realize multi-touch. [Embodiment] The touch input device provided by the present technical solution will be further described in detail below in conjunction with the plurality of embodiments and the multiple figures. Referring to FIG. 1 and FIG. 2 together, the first embodiment of the present invention provides a touch input device 1A, which includes an infrared light source module 11A, a 098120178, a form number A0101, a fifth page, and a total of 17 Page 0902034299-0 [0008] 201101128 A polarizing plate 1 220, a stress sensing sheet 1 30, a second infrared camera 14 〇, two second polarizing plates 150, and an image processor 160. [0011] The infrared light source module 110 is configured to provide infrared light. In this embodiment, the infrared light source module 11A includes a plurality of infrared light sources ill and a light guide plate 112. The infrared light source 111 is for emitting infrared light and is incident on the infrared light guide plate 丨i 2 , and the light guide plate 112 is used for uniformly emitting the infrared light incident from the infrared light source 11 从 from the light guide plate 112. In this embodiment, the infrared light source mode stage 〇 includes a four-infrared light source 111. The infrared light source 111 can be an infrared light emitting diode or an infrared laser light source. In this embodiment, the light guide plate 112 is a rectangular parallelepiped having a light-emitting surface 1121, a bottom surface 1122 opposite to the light-emitting surface 1121, and a light-incident surface 1123 connected between the light-emitting surface 1121 and the bottom surface 1122. A plurality of dots (not shown) are disposed on the bottom surface 1122 for diffusing the infrared light source lu into the light guide plate 112 so that the infrared light passes through the light exiting surface. The light guide plate 112 is uniformly emitted. Four infrared beam sources lu are arranged parallel to the entrance face 1123. The light exit surface of each of the infrared light sources i U is opposite to the light incident surface 1123 of the light guide plate ι 2 . Of course, the shape of the guide wrap 112 is not limited to a rectangular parallelepiped, and may be other shapes such as a cylinder, a truncated cone, or a polygonal prism. Of course, the infrared light source module 110 is not limited to the structure in the embodiment, and may also include a plurality of infrared light sources of the plurality of array rows, and only f may make the light emitting surface of each of the infrared light sources oppose the first polarizing plate 12A. The first-polarized (four) infrared source ·11{) provides infrared light that is converted to infrared polarized light. The first polarizing plate m is disposed between the infrared light source module group no and the stress sensing sheet 130. First—polarizing plate 12〇 and light guide plate 098120178 Form No. A0101 Page 6 of 17 0982034299-0 [0012] The light emitting surface 1121 of 201101128 112 is opposite to convert the infrared light emitted from the light emitting surface 1121 into polarized light. In this embodiment, the first polarizing plate 120 has a rectangular sheet shape, which is a linear polarizing plate. Preferably, the first polarizing plate 120 is disposed coaxially with the light emitting surface 1121. [0013] The 感 应力 stress sensing sheet 130 is disposed on a side of the first polarizing plate 120 away from the infrared light source module 110. In the present embodiment, the stress sensing sheet 130 has a rectangular sheet shape having a touch surface 131 and a back surface 132 opposite to the touch surface, and the back surface 132 is opposed to the first polarizing film 120. The stress sensing sheet 130 is made of a light transmissive material capable of generating internal stress due to the action of an applied force, as it may be made of various plastic or liquid crystal materials having the above properties. When the object is touched to the touch surface 131, the pressure applied to the touch surface 131 causes stress to be generated at a position corresponding to the inside of the stress sensing sheet 130. When stress is generated inside the position corresponding to the impact sensing piece 130, when the light passes through the above position, the light will undergo birefringence. This is because the stress in the stress sensing sheet 130 produces a certain degree of anisotropy, resulting in birefringence. That is, the optical path difference generated by the calendering and the e-light in the transparent medium having stress is not zero, and the optical path difference between the calendering and the e-light is related to the stress distribution. If the medium is formed into a sheet shape and inserted between the two polarizing plates, the difference in the optical path difference caused by the neon light and the e light is different at different positions, and the difference between the light and the e light is caused by the first polarization. Interference fringes can be observed in the polarizing plate in which the sheet 120 is polarized in the vertical direction. Where the stress is concentrated, the anisotropy is stronger and the interference fringes are finer. The infrared camera 140 is opposed to the touch surface 131. In this embodiment, the touch input device 100 includes two infrared cameras 140. The two infrared cameras are disposed above the two apex angles of the same side of the contact surface 131. Two red 098120178 Form No. A0101 Page 7 of 17 0982034299-0 [0014] 201101128 The area overlapped by the field of view 141 of the external camera 140 covers the entire touch surface 131. The two infrared cameras 140 are spaced apart from the contact surface 131 by a distance determined by the size of the contact surface 131. The larger the area of the touch surface 131, the further the distance. The infrared camera 140 is not limited to two in the embodiment, and may be more than two, and the number thereof may be set according to the size of the contact surface 131 and the field of view of the infrared camera 140. The larger the area of the touch surface 131, the greater the number of infrared cameras 140 required; the smaller the field of view of the infrared camera 140, the greater the number of infrared cameras 140 required. The infrared camera 140 is preferably a wide-angle infrared camera having a field of view angle range of between 90 and 120 degrees. [0015] The second polarizing plate 150 is disposed between the contact surface 131 and the infrared camera 140. The second polarizing plate 150 is for polarizing light incident thereto from the stress sensing sheet 130 such that the light is converted into light having the same polarization direction as that of the second polarizing film 150. In this embodiment, the touch input device 100 includes two second polarizing plates 150, and each of the second polarizing plates 150 is mounted on an object side of an infrared camera 140. The polarization angles of the second polarizer 150 and the first polarizer 120 are perpendicular to each other. [0016] It can be understood that the second polarizing plate 150 can also be packaged in each infrared camera 140. [0017] The infrared light emitted by the infrared light source module 110 is converted into polarization with the first polarizing plate 120 through the first polarizing plate 120. The polarized light of the same direction is polarized, and when the polarized light passes through the stress-sensing sheet 130 where no stress is generated, the polarized light does not undergo birefringence. The polarization directions of the first polarizer 120 and the second polarizer 150 are perpendicular to each other, and the infrared camera 140 does not exhibit an image in which interference fringes are formed by the second polarizer 150. However, the infrared light source module 110 098120178 Form No. A0101 Page 8 / Total 17 page 0992034299-0 201101128 After the infrared light emitted by the first polarizing film 120 is converted into the polarized light of the same polarization direction as the first polarizing plate 120, When the polarized light passes through the stress sensing sheet 130 that is stressed by the touch, the polarized light is birefringent at a position corresponding to the generated stress because the polarization directions of the first polarizing plate 120 and the second polarizing plate 150 are perpendicular to each other. The infrared camera 140 forms an image of interference fringes at a position corresponding to the stress generated by the second polarizing film 150. [0018] The image processor 160 is coupled to the two infrared cameras 150. The image processor ^ 160 is configured to receive an image signal obtained by each infrared camera 150 and process the image signal. The image processor 160 processes the images obtained by the two infrared cameras 150 to obtain the specific position of the position on the touch surface 131 respectively; and when the position of the touch moves, the image processor 160 according to the image processor 160 The image signal obtained by the connected infrared camera 150 determines the trajectory of the movement of the touch. It can be understood that the touch input device 100 can also be used to simultaneously identify the plurality of touch positions and the touch track. [0019] Referring to FIG. 3 and FIG. 4, a second embodiment of the present invention provides a touch input device 200 having a structure similar to that of the touch input device 100 provided in the first embodiment. The difference is that the infrared light source module 210 of the touch input device 200 has a reflective plate 213 and has two light incident surfaces 2123. In addition, the touch input device 20 0 includes only one infrared camera 240 and one second polarizer 250. The reflector 213 is disposed on the bottom surface 2122 of the light guide plate 212 to prevent light from exiting from the bottom surface 2122, thereby improving the utilization of light. The light guide plate 212 has two light incident surfaces 2123 connected between the light emitting surface 2121 and the bottom surface 2122, and the two light incident surfaces 2123 are opposite to each other. Parallel to each 098120178 Form No. A0101 Page 9 of 17 0982034299-0 201101128 Each of the entrance faces 112 3 is provided with four infrared light sources 21! to improve the brightness of the light guide plate 212. An infrared camera 24 is disposed on a central axis of the touch surface 231 of the stress sensing sheet 230, and a second polarizing plate 25 is disposed between the stress sensing sheet 230 and the infrared camera 24A. The field of view of the infrared camera 240 covers the entire touch surface mi. [0020] The touch input device provided by the technical solution converts infrared light generated by the infrared light source module into polarized light by using a first polarizing plate, and the polarized light is generated by a stress sensing piece having stress due to application of an external force. In the phenomenon of birefringence, the infrared camera obtains the image through the image processor through the second polarizer having the direction perpendicular to the oscillating direction of the first polarizer, so that the position and the trajectory of the touch object can be obtained by the touch object. Touch input. Therefore, the touch input device provided by the technical solution can accurately sense the position of the touch and the track of the touch, and can realize multi-touch. [0021] In summary, the present invention has indeed met the requirements of the invention patent, and is legally mentioned. ... : ·. Patent application. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by persons skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims. BRIEF DESCRIPTION OF THE DRAWINGS [0022] FIG. 1 is a schematic cross-sectional view of a touch input device according to a first embodiment of the present technical solution. 2 is a top plan view of the touch input device of FIG. 1. 3 is a cross-sectional view of a touch input device according to a second embodiment of the present technical solution. 098120178 Form No. A0101 Page 10 of 17 0982034299-0 201101128 A schematic view. [0025] FIG. 4 is a top plan view of the touch input device of FIG. 3. [Description of main component symbols] [0026] Touch input device 100' 200 Infrared light source module 110, 210 Infrared light source 111, 211 Light guide plate 112, 212 Light-emitting surface 1121, 2121 Bottom surface 1122, 2122 Light-in surface 1123, 2123 A polarizing plate 120 stress sensing sheet 130, 230 touch surface 131, 231 back surface 132 infrared camera 140' 240 field of view 141 second polarizing film 150, 250 image processor 160 reflecting plate 213 Form No. 101 0101 Page 11 of 17 Page 0982034299-0