五、新型說明： 【新型所屬之技術領域】 本創作關於一種物件感測裝置，尤指一種可有效改善整體影像 照度之物件感測裝置。 【先前技術】 由於目前的消費性電子產品皆以輕、薄、短、小為設計之方向， 因此，產品上已無空間容納如滑鼠、鍵盤、觸控筆等傳統輪入之工 具。隨著觸控裝置技術的進步，在各種消費性電子產品中，例如顯 不器、一體機（All in One)、行動電話、個人數位助理（Pers〇nal Digitai Assistant，pDA)等產品已廣泛地使用觸控装置作為其資料輸入之 =具。此外’在觸控裝置日趨成熟之下，擁有大尺寸與多點觸控技 術的電子裝置將成為未㈣技。目前，光學式敏裝置相較並他 方式，如電_ m超音《顿辟像翁，以彳+ 士 與更易達成_勢。 像;切，有更低成本 二:閱第1圖’第i圖為先前技術的光學式觸控裝置％ 示，光學式觸控裝置1包含-指示咖 =早以a、12b以及三個發光單元14。指 貝邊㈣三_ S3鱗， 此外，弟—側邊S1以及第二側扣相交於-第-祕C1，第- M410279 邊S1以及第四側邊S4相交於一第二角落C2，第三側邊S3以及第 四側邊S4相交於一第三角落C3，而第二側邊S2以及第三側邊S3 相交於一第四角落C4。影像感測單元12a設置於指示平面10之第 一角落C1 ’而影像感測單元12b設置於指示平面1〇之第二角落 C2。三個發光單元14分別設置於第二側邊S2、第三側邊幻以及第 四側邊S4上，用以提供影像感測單元12a、12b感測一物件（例如： 手指或觸控筆）之光源。發光單元14可為獨立光源（例如，發光二 φ 極體）或由導光柱以及光源组成。 由於影像感測單元12a以及影像感測單元12b之結構與作用原 理相同，以下僅針對影像感測單元12a作詳細的說明。如第1圖所 不，影像感測單元12a包含一鏡頭模組12〇、一光圈模組122以及 -影像感測模組124，且鏡頭模組12〇設置於光圈模組122與影像 感測模組124之間。鏡頭模組120具有一光軸LA。光圈模組122 具有-光圈開口 1220，用以調節由指示平面1〇上不同位置入射影 像感測單^12a之進光量。此外，光關口 mG具有—開口方向轴 〇A。於先前技術中，鏡頭模組120之光軸LA與光圈開口 122〇之 3方向軸OA重合，且光軸LA指向指示平面上的—位置p， 而將第一側邊Si與第二側邊S2間的爽角等分成兩個45度角。 t 一請參閱第2圖，第2圖為影像感測單元12a感測之影像照度與 指示:面1G左半區（.以光軸LA為準）上不同位置的關係圖。需說 勺疋第2圖中的縱座標（即影像照度）係進行過正規化 5V. New description: [New technical field] This creation is about an object sensing device, especially an object sensing device that can effectively improve the overall image illumination. [Prior Art] Since current consumer electronic products are designed in a light, thin, short, and small direction, there is no space on the product to accommodate traditional wheeling tools such as a mouse, a keyboard, and a stylus. With the advancement of touch device technology, products such as display devices, All in One, mobile phones, and personal digital assistants (PDA) have been widely used in various consumer electronic products. Use the touch device as its data input. In addition, electronic devices with large-size and multi-touch technologies will become unskilled as touch devices become more mature. At present, the optical sensitive device is compared with other methods, such as the electric _ m supersonic "Don's like a singer, with 彳 + 士 and easier to achieve _ potential. Like, cut, have lower cost 2: Read Figure 1 'i' is the prior art optical touch device%, the optical touch device 1 contains - indicating coffee = early a, 12b and three illuminating Unit 14. Refers to the side of the shell (four) three _ S3 scale, in addition, the brother - side S1 and the second side buckle intersect at - the first secret C1, the first - M410279 side S1 and the fourth side S4 intersect at a second corner C2, third The side S3 and the fourth side S4 intersect at a third corner C3, and the second side S2 and the third side S3 intersect at a fourth corner C4. The image sensing unit 12a is disposed at a first corner C1' of the indication plane 10 and the image sensing unit 12b is disposed at a second corner C2 of the indication plane 1〇. The three light-emitting units 14 are respectively disposed on the second side S2, the third side, and the fourth side S4, so as to provide the image sensing unit 12a, 12b to sense an object (for example: a finger or a stylus) Light source. The light unit 14 can be an independent light source (for example, a light-emitting diode) or composed of a light guide column and a light source. Since the structure and function of the image sensing unit 12a and the image sensing unit 12b are the same, the image sensing unit 12a will be described in detail below. As shown in FIG. 1 , the image sensing unit 12 a includes a lens module 12 , an aperture module 122 , and an image sensing module 124 , and the lens module 12 is disposed on the aperture module 122 and image sensing. Between modules 124. The lens module 120 has an optical axis LA. The aperture module 122 has a diaphragm opening 1220 for adjusting the amount of light incident from the incident image sensing unit 12a at different positions on the indicating plane 1〇. Further, the light gate mG has an opening direction axis 〇A. In the prior art, the optical axis LA of the lens module 120 coincides with the 3-axis axis OA of the aperture opening 122, and the optical axis LA points to the position p on the indication plane, and the first side Si and the second side are The cool angle between S2 is equally divided into two 45 degree angles. t Please refer to FIG. 2, and FIG. 2 is a diagram showing the relationship between the image illuminance and the indication sensed by the image sensing unit 12a: the left half of the surface 1G (which is based on the optical axis LA). It should be said that the ordinate (ie, image illuminance) in Figure 2 has been normalized.
TBTII2W (normalized)處理，而橫座標係指示平面10上的不同位置偏離光 軸LA之夹角。舉例而言，若位置P偏離光軸！^八之夾角定義為〇 度，則第三角落C3偏離光轴LA之夾角為15度，而第二角落C2 偏離光軸LA之夾角為45度。如第1圖所示，由於開口方向軸〇A 與光軸LA重合，故第二角落C2偏離開口方向軸〇A之夾角亦為 45度，且第三角落C3偏離開口方向軸〇八之夾角亦為15度。換言 之，第二角落C2偏離開口方向軸0A之夾角大於第三角落㈡偏離 開口方向軸OA之夾角，故由第二角落C2入射影像感測單元12& 之進光量較少，因此影像感測單元12a感測到第二角落C2之影像 照度較低（如第2圖所示），使得光學式觸控裝置丨之整體影像照度 會有不均勻的問題產生。 【新型内容】 因此，本創作的目的之一在於提供一種可有效改善整體影像照 度之物件感測裝置。 根據一實施例，本創作之物件感測裝置包含一指示平面以及— 影像感測單元。指示平面具有一第一側邊以及一第二側邊。第—側 邊以及第二側邊相交於一角落，且影像感測單元設置於此角落。影 像感測單7°包含一鏡頭模組、一光圈模組以及一影像感測模組。光 圈模組與影像感測模組分別與鏡頭模組鄰近設置。鏡頭模組具有— 光軸光圈模組具有一光圈開口。光圈開口定義一開口方向軸，且 開口方向軸與光軸不平行。 M410279 “綜上所述，由於影像感測單元之光醒組之開口方向轴與鏡頭 模”且之光軸不平行，g此可根據指示平面上的不同位置調整光圈模 組之進光量，進而使影像_單元麟齡的雜日績之分配。藉 此即可有效改善物件感測裝置之整體影像照度。 關於本創作之優點與精神可以藉由以τ_作詳述及所附圖式 得到進一步的瞭解。 【實施方式】 請參閱第3 ® ’第3 _根據本創作—實_之物件感測裝置 3的示意圖。如第3圖所示’物件感測裝置3包含一指示平面％、 兩個影像感測單元32a、32b以及三個發光料34。指示平面3〇具 有一第—側邊S卜一第二側邊S2、一第三側邊％以及一第四側邊 料。第—側邊81與第三側邊S3相對，而第二側邊％與第四側邊 S4相對。於此實施例中，第—側邊Sl與第三側邊幻之長度大於第 二側邊S2與第四側邊S4之長度。此外，第—側邊si以及第二側 邊，相交於一第一角落α，.第一側邊幻以及第四側邊以相交於 -第二角落C2 ’第三側邊S3以及第四側邊以相交於一第三角落 C3 ’而第一側邊S2以及第三側邊S3相交於一第四角落&影像 感測單元32a設置於指示平面3〇之第一角落，而影像感測單元 灿設置於指示平面30之第二角落C2。三個發光單元％分別設置 於才曰不平面30之周圍’用以提供影像感測單元32a、]感測一物 7 件（例如：手指或觸控筆）之光源。於此實施例中，三個發光單元 34可分別設置於第二側邊S2、第三側邊S3以及第四側邊S4上。 於實際應用中，影像感測單元32a、32b可為電荷耦合元件 (Charge-coupled Device，CCD )感測器或互補式金屬氧化半導體 (Complementary Metal-Oxide Semiconductor，CMOS)感測器。此 外，母一個發光單元34可為獨立光源（例如，發光二極體）或由導 光柱以及光源組成。需說明的是，發光單元34的數量與設置位置可 根據貫際應用而決定，不以第3圖所繪示的為限。一般而言，物件 感測裝置3中還會設有運作時必要的軟硬體元件，如顯示面板、中 央處理單元（Central Processing Unit，CPU)、記憶體（mem〇ry)、 儲存裝置（storagedevice)、電源供應器、作業系統等，視實際應用 而定。上述元件之功能為習知技藝之人可輕易達成並加以運用，在 此不再詳加贅述。 由於影像感測單元32a以及影像感測單元32b之結構與作用原 理相同，以下僅針對影像感測單元32a作詳細的說明。請參閱第4 圖，第4圖為第3圖中之影像感測單元仏的放大圖。如第4圖所 不，影像感測單元32a包含一鏡頭模組32〇、一光圈模組322以及 -影像感測模組324。光圈模組322與影像感測模組324分別與鏡 頭模組320鄰近設置。一般而言，鏡頭模組32〇係設置於光圈模版 322以及影像感測模組324之間。鏡頭模組32〇具有一光車由。光 圈模組322具有-光圈開口 322〇，用以調節由指示平面3〇上不同 M410279 :入射影像感測單元32a之進光 向㈣’且開口方向轴似與 ：： 〇A與第-側邊S1夾—第 ❿方向轴 〇2,且第二角度必大於第:且”第一側邊幻夾—第二角度 LA，t , ,t 又划。於此只施例中，鏡頭模組32〇 之光軸W姑示平㈣上的—位置p， 相0Α與光轴认之間具有-央角…實珊，夫二介 於0度與45度之間。較佳地，夹角㈣介於Η度與30度之間。舉 例而言，若光轴LA將第一侧邊S1與第二側邊幻間的炎角等分成 兩個45度角，則夹角α為Μ度。 請參閱第5圖，第5圖為影像感測單元瓜感測之影像昭度鱼 指示平面3G林區（料軸LA鱗）係圖^ 明的是，第5圖中的縱座標（即影像照度）係進行過正規化 (_allZed)處理，而橫座標係指示平面3()上__^_ 軸LA之炎角。舉例而言，若位置？偏離光机八之夹角定義為〇 度’則第三角落C3偏離光軸LA之夾角為15度，而第二角落C2 偏離光軸LA之夾角為45度。如第3圖所示，本創作可透過適當地 調整影像感測單元32a之光圈開π 之開σ方向轴〇A，使開口 方向轴ΟΑ偏向第二角落C2,故可提升由第二聽c2人射影像感 測單元3M之進光量，進而提升影像感測單元仏感測到第二角落 C2之影像照度’如第5 _示。#此，本_可使雜感測單元 32a獲得較佳的影像照度之分配，進而有效改善物件感測裝置3之 9 整體影像照度。 請參閱第6圖，第6圖為根據本創作另—實施例之影像感測單 元32a'的示意圖。如第6圖所示，影像感測單元32a，與上述之影像 感測單元32a的主要不同之處在於’影像感測單元32a係藉由光圈 模組322的整體傾斜以調整開口方向軸〇A，而影像感測單元 係藉由光圈模組322'之結構設計以調整開口方向軸〇A，使開口方 向軸OA與鏡頭模組320之光軸LA不平行。如第6圖所示，光圈 模組322'上形成有一斜孔（即光圈），使得光圈開口 322〇之開口方 向軸OA與鏡頭模組320之光軸LA之間具有夾角α。當第3圖中的 衫像感測單元32a以第6圖中的影像感測單元32a'替換時，影像减 測單元32a，亦可獲得較佳的影像照度之分配，進而有效改善Z件感 測裝置3之整體影像照度。 “ 凊參閱第7圖 …第7圖為根據本創作另一實施例之影像感測單 _ 32义的示意圖。如第7圖所示，影像感測單元32&，，與上述之影像 則單το 的主要不同之處在於，影像感測單元瓜”藉由光圈模 =322”之結構設計，以調整光圈開口 322〇之開口方向軸，使開 :方向軸〇A與鏡頭模組320之光軸LA不平行。如第7圖所示，汗 3模組322''上形成有—不規則孔洞（即光圈），使得光圈開口 322〇 ^ 口方向轴OA與鏡頭模組32〇之光轴LA之間具有失角⑽當第 ^中的影像感測單元32a以第7圖中的影像感測單元32田 i感測單A 32a’’亦可獲得較佳的影像照度之分配，進而有效改呈 10 物件感測褒置3之整體影像照度。 , 斤述由於衫像感測單元之光圈模組之開日方向軸與鏡頭 f且之光^平行’因此可根據指示平面上的不同位置調整光圈模 之進光m ’進而使影像細單元獲得較麵f彡賴紅分配。藉 .t ’即可有效改善物件感測I置之整體影像照度。此外，影像感測 單元之光圈模k可具有不_結構設計，以調配光圈模組之進光 • 置，同樣地可有效改善物件感測裝置之整體影像照度。 以上所述僅為本創作之較佳實施例，凡依本創作申請專利範圍 所做之均等變化與修飾，皆應屬本創作之涵蓋範圍。 【圖式簡單說明】 第1圖為先前技術的光學式觸控裝置的示意圖。 第2圖為影像感測單元感測之影像照度與指示平面左半區（以 • 光軸為準）上不同位置的關係圖。 第3圖為根據本創作一實施例之物件感測裝置的示意圖。 第4圖為第3圖中之影像感測單元的放大圖。 第5圖為影像感測單元感測之影像照度與指示平面左半區（以 光軸為乎）上不同位置的關係圖。 第6圖為拫據本創作另一實施例之影像感測單元的示意圖。 第7圖為根據本創作另一實施例之影像感測單元的示意圖。 11 M410279 【主要元件符號說明】 1 光學式觸控裝置 3 物件感測裝置 10 ' 30 指示平面 12a、12b、 影像感測單元 32a、32b、 32a' ' 32a" 14、34 發光單元 120、320 鏡頭模組 122、322、 光圈模組 124、324 影像感測模組 322' ' 322" 1220、3220 光圈開口 a 夾角 cd 第一角度 oQ 第二角度 Cl 第一角落 C2 第二角落 C3 第三角落 C4 第四角落 LA 光軸 OA 開口方向軸 SI 第一側邊 S2 第二側邊 S3 第三側邊 S4 第四側邊 P 位置The TBTII2W (normalized) process, and the abscissa indicates that the different positions on the plane 10 deviate from the optical axis LA. For example, if the position P deviates from the optical axis! The angle between the eight angles is defined as the degree of inclination, and the angle between the third corner C3 and the optical axis LA is 15 degrees, and the angle between the second corner C2 and the optical axis LA is 45 degrees. As shown in Fig. 1, since the opening direction axis 〇A coincides with the optical axis LA, the angle between the second corner C2 and the opening direction axis 〇A is also 45 degrees, and the third corner C3 is offset from the opening direction. Also 15 degrees. In other words, the angle between the second corner C2 deviating from the opening direction axis 0A is greater than the angle between the third corner (2) and the opening direction axis OA, so that the amount of light entering the image sensing unit 12& is smaller by the second corner C2, so the image sensing unit 12a senses that the image illumination of the second corner C2 is low (as shown in FIG. 2), so that the overall image illumination of the optical touch device may have unevenness. [New content] Therefore, one of the purposes of the present invention is to provide an object sensing device that can effectively improve the overall image illumination. According to an embodiment, the object sensing device of the present invention includes an indication plane and an image sensing unit. The indicating plane has a first side and a second side. The first side and the second side intersect at a corner, and the image sensing unit is disposed at the corner. The image sensing unit 7° includes a lens module, an aperture module, and an image sensing module. The aperture module and the image sensing module are respectively disposed adjacent to the lens module. The lens module has an optical aperture module having an aperture opening. The aperture opening defines an opening direction axis, and the opening direction axis is not parallel to the optical axis. M410279 “In summary, since the opening direction axis of the image sensing unit and the lens mode are not parallel, the optical axis can be adjusted according to different positions on the indication plane, and further The allocation of the image of the unit_unit aging age. Thereby, the overall image illumination of the object sensing device can be effectively improved. The advantages and spirit of this creation can be further understood by taking τ_ as a detailed description and the drawings. [Embodiment] Please refer to the diagram of the 3 ® '3rd _ according to the creation-real object sensing device 3. As shown in FIG. 3, the object sensing device 3 includes an indication plane %, two image sensing units 32a, 32b, and three illuminants 34. The indicating plane 3 has a first side Sb, a second side S2, a third side %, and a fourth side material. The first side 81 is opposed to the third side S3, and the second side % is opposed to the fourth side S4. In this embodiment, the lengths of the first side S1 and the third side edge are greater than the lengths of the second side S2 and the fourth side S4. In addition, the first side si and the second side intersect at a first corner α, the first side edge and the fourth side intersect to the second corner C2 'the third side S3 and the fourth side The first side S2 and the third side S3 intersect at a fourth corner & the image sensing unit 32a is disposed at the first corner of the indicating plane 3〇, and the image sensing is performed. The unit can be disposed at the second corner C2 of the indication plane 30. The three light-emitting units are respectively disposed around the area of the surface 30 to provide the image sensing unit 32a, a light source for sensing a piece of material (for example, a finger or a stylus). In this embodiment, three light emitting units 34 are respectively disposed on the second side S2, the third side S3, and the fourth side S4. In practical applications, the image sensing units 32a, 32b may be a Charge-coupled Device (CCD) sensor or a Complementary Metal-Oxide Semiconductor (CMOS) sensor. In addition, the mother-emitting unit 34 can be an independent light source (e.g., a light-emitting diode) or composed of a light guide and a light source. It should be noted that the number and arrangement positions of the light-emitting units 34 can be determined according to the continuous application, and are not limited to those shown in FIG. Generally, the object sensing device 3 is also provided with soft and hard components necessary for operation, such as a display panel, a central processing unit (CPU), a memory (mem〇ry), and a storage device (storagedevice). ), power supply, operating system, etc., depending on the application. The functions of the above-described components can be easily achieved and utilized by those skilled in the art and will not be described in detail herein. Since the structure and function of the image sensing unit 32a and the image sensing unit 32b are the same, the image sensing unit 32a will be described in detail below. Please refer to FIG. 4, which is an enlarged view of the image sensing unit 第 in FIG. As shown in FIG. 4, the image sensing unit 32a includes a lens module 32A, an aperture module 322, and an image sensing module 324. The aperture module 322 and the image sensing module 324 are disposed adjacent to the lens module 320, respectively. Generally, the lens module 32 is disposed between the aperture template 322 and the image sensing module 324. The lens module 32 has a light vehicle. The aperture module 322 has a diaphragm opening 322 〇 for adjusting different M410279 on the indicating plane 3: the incoming light direction (four)' of the incident image sensing unit 32a and the opening direction axis is similar to: 〇A and the first side S1 clip - the second direction axis 〇 2, and the second angle must be greater than the first: and "the first side magic clip - the second angle LA, t, , t and draw. In this embodiment, the lens module 32 The optical axis of the 〇 姑 姑 姑 姑 四 四 四 四 四 四 四 四 四 四 位置 位置 位置 位置 位置 位置 位置 位置 位置 位置 位置 位置 位置 位置 位置 位置 位置 位置 位置 位置 位置 位置 位置 位置 位置 位置 位置 位置 位置 位置 位置 位置 位置 位置Between the twist and 30 degrees. For example, if the optical axis LA divides the inflammatory angle between the first side S1 and the second side into two angles of 45 degrees, the angle α is the twist. Please refer to Figure 5, Figure 5 is the image sensing unit melon sensing image Zhaodu fish indicating plane 3G forest area (material axis LA scale) system ^ Ming, is the ordinate in Figure 5 (ie image The illuminance is normalized (_allZed), and the abscissa indicates the inflammatory angle of the __^_ axis LA on the plane 3(). For example, if the position is deviated from the angle of the light machine, the angle is defined as the 〇 degree. 'The third corner C3 is offset from the optical axis LA by an angle of 15 degrees, and the second corner C2 is offset from the optical axis LA by an angle of 45 degrees. As shown in FIG. 3, the present invention can appropriately adjust the aperture of the image sensing unit 32a by π. Opening the σ direction axis 〇A, the opening direction axis ΟΑ is biased toward the second corner C2, so that the amount of light entering by the second listening c2 human image sensing unit 3M can be increased, thereby improving the image sensing unit and sensing the second corner. The image illuminance of C2 is as shown in the fifth _. This allows the miscellaneous sensing unit 32a to obtain a better distribution of image illuminance, thereby effectively improving the overall image illuminance of the object sensing device 3. 9 Figure 6 is a schematic diagram of an image sensing unit 32a' according to another embodiment of the present invention. As shown in Fig. 6, the image sensing unit 32a is mainly different from the image sensing unit 32a described above in that The image sensing unit 32a adjusts the opening direction axis A by the overall tilt of the aperture module 322, and the image sensing unit is designed by the aperture module 322' to adjust the opening direction axis A to make the opening direction The axis OA is not parallel to the optical axis LA of the lens module 320. As shown in FIG. 6, an aperture (ie, an aperture) is formed on the aperture module 322' such that an aperture angle OA between the aperture direction OA of the aperture opening 322 and the optical axis LA of the lens module 320 has an angle α. When the shirt image sensing unit 32a is replaced by the image sensing unit 32a' in FIG. 6, the image reducing unit 32a can also obtain a better image illumination distribution, thereby effectively improving the Z component sensing device 3. Overall image illumination. "See Fig. 7... Fig. 7 is a schematic diagram of an image sensing unit according to another embodiment of the present creation. As shown in FIG. 7, the main difference between the image sensing unit 32&, and the above-mentioned image is το is that the image sensing unit is designed by the aperture mode = 322" to adjust the aperture opening. The opening direction axis of 322 , is such that the opening direction axis 〇A is not parallel to the optical axis LA of the lens module 320. As shown in Fig. 7, the sweat 3 module 322'' is formed with irregular holes (i.e., apertures), so that there is a loss between the aperture opening 322 and the optical axis LA of the lens module 32. The angle (10) can also obtain a better image illumination distribution by using the image sensing unit 32 in the image sensing unit 32 of FIG. 7 to sense the single image A 32a′′, thereby effectively changing the sense of 10 objects. Measure the overall image illumination of the device 3. Because the opening direction axis of the aperture module of the shirt image sensing unit is parallel to the lens f and the light is parallel to each other, the aperture light of the aperture mode can be adjusted according to different positions on the indication plane to obtain the image thin unit. The face is more than the red distribution. By .t ’, the overall image illumination of the object sensing I can be effectively improved. In addition, the aperture mode k of the image sensing unit can have a non-structural design to adjust the aperture of the aperture module, which can effectively improve the overall image illumination of the object sensing device. The above descriptions are only preferred embodiments of the present invention, and all changes and modifications made in accordance with the scope of patent application of this creation should be covered by this creation. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of a prior art optical touch device. Figure 2 is a diagram showing the relationship between the image illuminance sensed by the image sensing unit and the left half of the indication plane (which is based on the optical axis). 3 is a schematic view of an object sensing device according to an embodiment of the present invention. Fig. 4 is an enlarged view of the image sensing unit in Fig. 3. Figure 5 is a diagram showing the relationship between the image illuminance sensed by the image sensing unit and the left half of the indication plane (in terms of the optical axis). Figure 6 is a schematic diagram of an image sensing unit according to another embodiment of the present invention. FIG. 7 is a schematic diagram of an image sensing unit according to another embodiment of the present creation. 11 M410279 [Description of main component symbols] 1 Optical touch device 3 Object sensing device 10' 30 Indication plane 12a, 12b, image sensing unit 32a, 32b, 32a' '32a" 14, 34 Illumination unit 120, 320 lens Module 122, 322, aperture module 124, 324 image sensing module 322' '322" 1220, 3220 aperture opening a angle cd first angle oQ second angle Cl first corner C2 second corner C3 third corner C4 Fourth corner LA optical axis OA opening direction axis SI first side S2 second side S3 third side S4 fourth side P position
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