201003048 六、發明說明 【發明所屬之技術領域】 本發明係有關於將測定對象之色彩之特性加以測定時 所使用的測定用光學系，是有關於將彩色LCD的顯示特 性（例如色度、亮度、色差等）加以測定的色彩儀上所能理 想適用的測定用光學系。 【先前技術】 先前以來，作爲計測彩色LCD之顯示特性（例如色 度、亮度、色差等）之色彩儀中所使用的測定用光學系， 爲了在光強度微弱的情況下仍可正確地測定出測定對象的 色彩特性，具備一接物透鏡，其係具有，在來自測定對象 之被測定領域之光束當中僅將出射角度在所定値以下之光 束予以聚光之正的光焦度，使已被該接物透鏡所聚光之光 束，入射至由複數根光纖所集束而形成之導光體的入射端 (: 面，將該導光體作3分割，使各光束從所被分割之各導光 體的出射端面出射，將從該各出射端面所出射得各光束， 分別以受光元件加以受光，基於光的三刺激値（R、G、B) 所關連之光電轉換訊號，來進行測定對象之色彩特性的計 測者，已爲公知（參照專利文獻1)。 [專利文獻1]日本特開2002-3 1 8080號公報 【發明內容】 [發明所欲解決之課題] -5- 201003048 可是，先前，在該測定用光學系中’爲了獲得光的三 剌激値，而在各受光元件的前面’配設有對R (紅）、 B(藍）、G(綠）之各波長領域具有感度之分光感度補正濾光 片。在該分光感度補正濾光片，通常會採用彩色玻璃濾光 片。 然而，此種彩色玻璃濾光片，係由於穿透率較低，所 以入射至受光元件的受光量會變少’在光強度微弱的情況 下，色彩特性的測定相當困難，並且爲了使偵測感度提 升，就測定對象的色彩特性的正確測定而言，並不充分。 於是，考慮使用穿透率高的干涉濾光片來作爲分光感 度補正濾光片，但是，干涉濾光片係爲，若入射至該干涉 濾光片的光束的入射角越大，則光的波長會往越短之方向 平移，因此具有難以正確測定色彩特性之問題。 又，若將接物透鏡的焦距設定得較大，則可縮小在導 光體入射端面位置上的入射角，使該入射角被保持而傳播 至導光體出射端面而出射，可縮小對干涉濾光片的入射 角’但若採取此種構成，則會導致測定用光學系全長變長 之問題。 本發明係有鑑於上記情事而硏發，目的在於提供一 種’不必加長光學系之全長，就可使用干涉用濾光片來使 偵測感度提升的測定用光學系。 [用以解決課題之手段] 申請專利範圍第1項所記載之發明，係一種測定用光 -6- 201003048 學系，其特徵爲，具備：第1透鏡，係面對於測定對 具有正的光焦度，且將來自前記測定對象之被測定領 各點的光束予以聚光而使其準直（collimate);和開 圈，係被配設於前記第1透鏡的略後側焦點位置，限 前記各點入射至前記第1透鏡之光束的入射角度；和 透鏡，係在該開口光圈的略配設位置具有前側焦點， 於通過前記開口光圈而入射之光束，將前記被測定領 像形成在後側焦點位置；和光束分割手段，在該第2 的略後側焦點位置具有入射端面，且將入射至該入射 的各光束，分割成3個光束群；和受光手段，係隔著 於前記光束分割手段的出射面而配設的干涉濾光片而 記各光束群予以受光；在前記光束分割手段之入射端 置上的光束之入射角是被設定成小於在前記開口光圈 上的入射角，來自前記受光手段的輸出，係被使用於 特性之測定。 申請專利範圍第2項所記載之發明，係如申請專 圍第1項所記載之測定用光學系，其中，爲了使前記 分割手段之入射端面位置上的入射角小於前記開口光 置上的入射角，前記光束分割手段的入射端面之大小 設定成大於前記開口光圈之大小。 申請專利範圍第3項所記載之發明，係如申請專 圍第2項所記載之測定用光學系，其中，在前記光束 手段的入射端面，配設有用來規定前記被測定領域之 的視野光圏。 象而 域之 口光 制從 第2 且基 域的 透鏡 端面 對向 將前 面位 位置 色彩 利範 光束 圈位 是被 利範 分割 大小 201003048 申請專利範圍第4項 圍第3項所記載之測定用 段’係由將多數根光纖集 光纖係被集束成，使得成 位置關係是呈擬似性隨機 申請專利範圍第5項 圍第4項所記載之測定用 係由對向於前記出射端面 出射之光束予以聚光之正 該聚光透鏡所聚光之光線 [發明效果] 若依據申請專利範圍 達成以下效果：不必加長 瀘光片來提升偵測感度。 又，若依據申請專利 了上記效果外，還可達成 【實施方式】 以下，一面參照圖面 的測定用光學系的發明實 [實施例] 圖1係本發明所述之 所記載之發明，係如申請專利範 光學系，其中，前記光束分割手 合成束的導光體所成，該多數根 像於前記入射端面之光束的成像 〇 所記載之發明，係如申請專利範 光學系，其中，前記受光手段， 而配設且具有將從該出射端面所 的光焦度的聚光透鏡、和將已被 予以受光用的受光部，所構成。 第1至4項所記載之發明，則可 光學系之全長，就可使用干涉用 範圍第5項所記載之發明，則除 受光感度之提升。 ，一面說明本發明所述之色彩儀 施形態。 色彩儀的測定用光學系的槪略構 -8 - 201003048 成的說明圖’於此圖1中’符號1係爲液晶盤，符號i a 係爲液晶盤1的顯示面’ 2係測定用光學系。此處，顯示 面la係爲測定對象’該顯示面ia的一部分是被當成被測 定領域。 測疋用先學系2係由同體3與框體4所槪略構成。在 筒體3的內部係設有第1透鏡5、開口光圈6、第2透鏡 7，在框體4中則設有例如作爲光束分割手段的導光體 8、受光手段9、含演算電路1〇的其他測定電路、電源電 路等、測定開關等之測定時所需要的機構。 筒體3的先端3 a係在測定之際會接觸於顯示面1 a， 第1透鏡5係在測定之際會面對於顯示面1 α。筒體3係 擔任遮蔽外光的角色，並用來規定顯示面la對第1透鏡 5之距離。 第1透鏡5係具有正的光焦度，是以使得其前側焦點 位置fl是位於顯示面la上的方式而配設。該第1透鏡5 係負責將來自顯示面1 a之被測定領域的光束加以聚光， 並使其準直（collimate)。於此圖1中，符號Pal〜Pa3係 表示從點a入射至第1透鏡5之光束，符號Pbl〜Pb3係 表示從點b入射至第1透鏡5之光束，符號Pci〜Pc3係 表示從點c入射至第1透鏡5之光束，來自被測定領域之 各點a、b、c的光束係被第1透鏡5所聚光，分別被予以 準直而導入至開口光圈6。 開口光圈6係被配設於第1透鏡5的後側焦點位置 f 1，，負責限制從各點a、b、c入射至第1透鏡5的光束的 -9- 201003048 入射角度。此處，該開口光圈6係負責以主光線P a2、 Pb2、Pc2爲基準，將超過正負2.5度之角度的從被測定領 域往第1透鏡5之光束予以遮光。 此處，以主光線Pa2、Pb2、Pc2爲基準，將超過正負 2.5度之角度的從被測定領域往第1透鏡5之光束予以遮 光的根據，是基於色彩儀所被要求之國際規格。 第2透鏡7係在開口光圈6的配設位置具有前側焦點 位置f2且負責基於通過開口光圈6所入射之光束而將被 測定領域的像形成在後側焦點位置f 2 '，該第2透鏡也是 和第1透鏡5同樣地具有正的光焦度。該第2透鏡7的焦 距係短於第1透鏡5的焦距。 導光體8係由多數光纖集結成束的光纖束所構成。這 些光纖束係在入射端面8 a側被收成一束，在出射端面則 是被分割成3條光纖束。該被分割成3條光纖束的各光纖 束的出射端面係分別以符號8br、8bg、8bb表示。該各出 射端面8br、8bg、8bb係如圖2所示，係被配置成，例 如，其中心位置Ο 1、02、03所連結成的線段是構成一正 三角形。 導光體8的入射端面8a係被配設在第2透鏡7的後 側焦點位置f 2 1 ’導光體8係擔任作爲將入射至入射端面 8a的像形成光束分割成3個光束群之光束分割手段之角 色。 該多數根光纖，係如圖3的模式性圖示，以使得成像 於入射端面8a之像形成光束的成像位置關係是擬似性隨 -10- 201003048 機的方式而被集束形成，藉此，從各出射端面8br〜8bb 所出射而入射至後述的各受光元件的像形成光束，係被擬 似性隨機地混合，而入射至該當各受光元件’因此可減輕 像形成光束的光量不均。 受光手段9，係由干涉濾光片11a〜11c與受光元件 1 2 a〜1 2 c所槪略構成。該各干涉濾光片1 1 a〜1 1 c係分別 對向於出射端面8br、8bg、8bb而配設。受光元件12a〜 1 2c係對應於各干涉濾光片1 1 a〜1 1 c而配置。 干涉濾光片1 1 a係具有，使得從出射端面8br所出射 的光束當中的紅色（R)光會穿透的濾光片特性，干涉濾光 片11b係具有，使得從出射端面8bg所出射的光束當中的 綠色（G)光會穿透的濾光片特性，干涉濾光片1 1 c係具 有，使得從出射端面8 bb所出射的光束當中的藍色（B)光 會穿透的濾光片特性。 受光元件12a係基於通過了干涉濾光片lla之紅色波 t 長帶的光而輸出光電轉換訊號，受光元件12b係基於通過 了干涉濾光片11b之綠色波長帶的光而輸出光電轉換訊 號，受光元件12c係基於通過了干涉濾光片lic之藍色波 長帶的光而輸出光電轉換訊號，各光電轉換訊號係被輸入 至演算電路1 〇及其他測定電路，藉由這些測定電路，測 定出色度、亮度、色差等之色彩特性。 在導光體8的入射端面8a，設有用來規定被測定領 域之大小的視野光圈13’藉此，來自被測定領域的多餘 光就會被遮光。又，視野光圈13的大小，亦即導光體8 -11 - 201003048 的入射端面8 a之大小，係被設定成大於開口光圈6的大 小，藉此，相對於在導光體8的入射端面8a配置在開口 光圈6時入射至該入射端面8a的各光束的最大入射角αΐ 而言，在導光體8的入射端面8a配置在第2透鏡7的後 側焦點位置f2'時入射至該入射端面8a的各光束的最大入 射角ct2可較爲緩和，其結果爲，即使使用了穿透率高的 干涉濾光片1 1 a〜1 1 C的情況下，仍可防止光的波長往短 波長方向平移，可正確地測定色彩特性。 又，若刻意在開口光圈6的位置配置入射端面8 a， 則入射至該入射端面8a的各像形成光束的最大入射端角 α 1會被保存，會傳播至出射端面8br〜8bb而出射，因 此在使用干涉濾光片1 1 a〜1 1 c來構成測定用光學系的情 況下，有必要爲了縮小最大入射角α 1而加長第1透鏡5 的焦距，又，由於導光體8的入射端面8a會因此而增 大，所以導光體8需要有足夠長度，必須要加長測定用光 學系的全長，但是，在本發明的實施形態中，將使用第1 透鏡5與第2透鏡7的測定用光學系設計成由遠心光學系 所成之構成，使透過第2透鏡7而入射至入射端面8a的 像形成光束的最大入射角α2是較最大入射角αΐ緩和之 構成，因此，不必加長測定用光學系之全長，可精簡地加 以構成。 理想而言，令開口光圈6的面積爲S 1，導光體8的 入射端面8a亦即視野光圈1 3的面積爲S2，以使得開口 光圈6的最大入射角αΐ的正弦與面積S1的積Sl.sino: -12- 201003048 1，是相等於最大入射角《2的正弦與面積S2的積S2· sin α2的方式，來配設第1透鏡5與第2透鏡7’同時’ 以使得被測定領域與入射端面8a是隔著第1透鏡5與第 2透鏡7而呈光學性共軛的方式，將入射端面8a對第2 透鏡7進行配設，較爲理想。 以上，在本發明的實施形態中，雖然是設計成使受光 元件12a〜12c直接對於干涉濾光片11a〜11c作對向配設 之構成，但如圖4所示，若在出射端面8br〜8bb與干涉 濾光片1 la〜1 lc之間，配置一具有把從出射端面8br〜 8bb所出射之光束加以聚光的正的光焦度的聚光透鏡14’ 使透過了構成受光部之一部分的干涉濾光片11a〜11c的 光束，被收束於受光元件12a〜12c的構成，則可更進一 步謀求受光感度之提升。 若依據本發明的實施形態，則由於可提升微弱光的偵 測感度，因此可達成，提升被測定領域的黑色測定感度之 效果。 【圖式簡單說明】 [圖1 ]本發明之測定用光學系的模式性圖示之說明 圖。 [圖2]圖1所示的出射端面之位置關係的平面圖。 [圖3 ]本發明所述之光纖束之一例子的模式性圖示之 斜視圖。 [圖4]本發明所述之測定用光學系另一例子的模式性 -13- 201003048 圖示之說明圖。 【主要元件符號說明】 1 :液晶盤 2 :測定用光學系 3 :筒體 4 :框體 5 :第1透鏡 6 :開口光圈 7 :第2透鏡 8 :導光體 9 :受光手段 1 0 :演算電路 1 3 :視野光圏 1 4 :聚光透鏡 1 1 a〜1 1 c :干涉濾光片 8 b r ' 8 b g ' 8bb:出身寸端面 12a〜12c:受光兀件 1 a :顯示面 3 a :先端 8 a :入射端面 Ο 1、Ο 2、Ο 3 :中心位置201003048 VI. Description of the Invention [Technical Fields of the Invention] The present invention relates to an optical system for measurement used for measuring characteristics of a color of a measurement object, and relates to display characteristics (for example, chromaticity and brightness) of a color LCD. , chromatic aberration, etc.) The optical system for measurement that is ideally applicable to a color meter to be measured. [Prior Art] The optical system for measurement used in the colorimeter for measuring the display characteristics (for example, chromaticity, luminance, chromatic aberration, etc.) of a color LCD has been accurately measured in the case where the light intensity is weak. The color characteristic of the measurement object includes a contact lens having a positive refractive power in which only a light beam having an emission angle below a predetermined angle is concentrated in a light beam from a measurement target area, so that The light beam condensed by the object lens is incident on an incident end of the light guide body formed by the bundle of a plurality of optical fibers (the surface is divided into three, so that the respective light beams are guided from the respective guides The light-emitting end face of the light body is emitted, and the light beams emitted from the respective output end faces are received by the light-receiving elements, and the photoelectric conversion signals associated with the three-stimulus 光 (R, G, B) of the light are used to measure the object. The measurement of the color characteristics is known (refer to Patent Document 1). [Patent Document 1] JP-A-2002-3 1 8080 [Summary of the Invention] [Problems to be Solved by the Invention] -5- 2010030 48. In the optical system for measurement, in the optical system for measurement, each of R (red), B (blue), and G (green) is disposed in front of each light-receiving element in order to obtain three-intensity excitation of light. In the wavelength field, there is a sensitivity-based spectral sensitivity correction filter. In the spectral sensitivity correction filter, a colored glass filter is usually used. However, such a colored glass filter is incident because of a low transmittance. The amount of light received by the light-receiving element is reduced. When the light intensity is weak, the measurement of the color characteristics is difficult, and in order to improve the detection sensitivity, it is not sufficient to accurately measure the color characteristics of the measurement object. Consider using an interference filter with a high transmittance as a spectral sensitivity correction filter, but the interference filter is such that the larger the incident angle of the light beam incident on the interference filter, the wavelength of the light It is difficult to accurately measure the color characteristics by shifting in the shorter direction. Further, if the focal length of the objective lens is set to be large, the incident angle at the position of the incident end face of the light guide body can be reduced, so that the incident angle can be reduced. When the incident angle is maintained and propagated to the light-emitting body exit end surface and is emitted, the incident angle of the interference filter can be reduced. However, if such a configuration is adopted, the entire length of the optical system for measurement becomes long. In view of the above, the purpose is to provide an optical system for measuring which can improve the detection sensitivity by using an interference filter without lengthening the entire length of the optical system. [Means for Solving the Problem] Patent Application Scope The invention according to the first aspect of the invention is characterized in that the invention is characterized in that: the first lens is provided, and the first lens has a positive refractive power for the measurement pair, and the measurement target is The light beam at each point of the collar is collected to be collimated, and the open circle is disposed at a slightly rear focus position of the first lens, and the light beam is incident on the light beam of the first lens. The incident angle; and the lens having a front focus at a slightly disposed position of the aperture stop, and a light beam incident through the aperture of the opening, forming a pre-recorded collar image at a rear focus position; And the beam splitting means has an incident end face at the second rear focus position, and divides the incident light beams into three beam groups; and the light receiving means is separated by the pre-recording beam splitting means The interference filter disposed on the surface is recorded by each of the light beam groups; the incident angle of the light beam placed at the incident end of the beam splitting means is set to be smaller than the incident angle on the aperture of the opening aperture, from the light receiving means The output is used to determine the characteristics. The invention described in claim 2 is the optical system for measurement described in the first aspect of the invention, wherein the incident angle at the incident end surface position of the pre-recording means is smaller than the incidence of the front opening light. The angle, the size of the incident end face of the beam splitting means is set to be larger than the size of the aperture of the opening. The invention according to the third aspect of the invention is the optical system for measurement described in the second aspect of the invention, wherein the incident end surface of the pre-recorded beam means is provided with a field of view for defining the field to be measured. Hey. The image of the image is from the lens end face of the 2nd and the base field, and the color position of the front position is the size of the segment. 201003048 The measurement segment described in item 4 of the fourth paragraph of the patent application scope 'Because the majority of the fiber-optic fiber bundles are bundled, so that the positional relationship is a pseudo-random patent application. The measurement system described in item 4 of the fifth item is made of a beam that is emitted from the front end of the exit end. The light concentrated by the condensing lens is concentrated [Effect of the Invention] According to the scope of the patent application, the following effects are achieved: it is not necessary to lengthen the glazing sheet to improve the detection sensitivity. In addition, the invention can be achieved in accordance with the above-mentioned effects of the patent application. [Embodiment] The invention of the optical system for measurement is shown in the following. FIG. 1 is an invention described in the present invention. For example, the invention relates to a patented optical system, wherein the pre-recorded beam splits the light guide body of the hand-splitting beam, and the invention is described in the image of the beam of the incident end face, such as the patent application optical system, wherein In the light receiving means, a collecting lens having a power from the exit end face and a light receiving portion for receiving light are disposed. In the invention according to the first to fourth aspects, the invention described in the fifth item of the interference range can be used for the entire length of the optical system, and the light sensitivity is improved. The color instrument configuration of the present invention will be described. Illustrated diagram of the optical system for measuring the colorimeter - 201003048. In the figure 1, the symbol 1 is a liquid crystal panel, and the symbol ia is a display surface of the liquid crystal panel 1 '2 optical system for measurement . Here, the display surface la is a measurement target'. A part of the display surface ia is regarded as a measured area. The first system of the test system is composed of the same body 3 and the frame 4. The first lens 5, the aperture stop 6, and the second lens 7 are provided inside the cylindrical body 3. The light guide body 8 as a beam splitting means, the light receiving means 9, and the arithmetic circuit 1 are provided in the casing 4. Other measuring circuits, power supply circuits, etc., which are required for measurement of switches and the like. The tip end 3 a of the cylindrical body 3 is in contact with the display surface 1 a during measurement, and the first lens 5 meets the display surface 1 α at the time of measurement. The cylinder 3 serves to shield the external light and is used to define the distance of the display surface 1a from the first lens 5. The first lens 5 has a positive refractive power and is disposed such that its front side focus position fl is located on the display surface 1a. The first lens 5 is responsible for condensing and collimating the light beams from the measurement target area of the display surface 1a. In Fig. 1, symbols Pal to Pa3 indicate light beams incident on the first lens 5 from the point a, symbols Pb1 to Pb3 indicate light beams incident on the first lens 5 from the point b, and symbols Pci to Pc3 indicate points from the point. c. The light beam incident on the first lens 5, the light beams from the respective points a, b, and c in the measurement area are collected by the first lens 5, and are collimated and introduced into the aperture stop 6. The aperture stop 6 is disposed at the rear focus position f1 of the first lens 5, and is responsible for limiting the incident angle of the light beam -9-201003048 incident on the first lens 5 from each of the points a, b, and c. Here, the aperture stop 6 is configured to shield the light beam from the measurement target to the first lens 5 by an angle of more than plus or minus 2.5 degrees with respect to the principal ray P a2, Pb2, and Pc2. Here, the basis for shielding the light beam from the measurement target region to the first lens 5 at an angle of more than plus or minus 2.5 degrees based on the principal ray Pa2, Pb2, and Pc2 is based on an international standard required for the colorimeter. The second lens 7 has a front focus position f2 at the position where the aperture stop 6 is disposed, and is responsible for forming an image of the area to be measured at the rear focus position f 2 ' based on the light beam incident through the aperture stop 6, the second lens Similarly to the first lens 5, it also has a positive refractive power. The focal length of the second lens 7 is shorter than the focal length of the first lens 5. The light guide body 8 is composed of a bundle of optical fibers in which a plurality of optical fibers are bundled. These bundles are bundled at the side of the incident end face 8a, and are split into three bundles at the exit end face. The exit end faces of the respective bundles divided into three bundles are denoted by reference numerals 8br, 8bg, and 8bb, respectively. The respective output end faces 8br, 8bg, and 8bb are arranged as shown in Fig. 2, for example, the line segments to which the center positions Ο 1, 02, and 03 are connected constitute a regular triangle. The incident end surface 8a of the light guide body 8 is disposed at the rear focus position f 2 1 ' of the second lens 7 as the light guide body 8 serves to divide the image forming light beam incident on the incident end surface 8a into three beam groups. The role of the beam splitting method. The plurality of optical fibers are schematically illustrated in FIG. 3 such that an imaging positional relationship in which the image formed on the incident end face 8a forms a light beam is formed in a manner similar to that of the -10-201003048 machine, whereby The image forming light beams which are emitted from the respective output end faces 8br to 8bb and incident on the respective light receiving elements to be described later are randomly mixed in a pseudo-like manner, and are incident on the respective light-receiving elements', thereby reducing the amount of light unevenness of the image forming light beam. The light receiving means 9 is constituted by the interference filters 11a to 11c and the light receiving elements 1 2 a to 1 2 c. Each of the interference filters 1 1 a to 1 1 c is disposed to face the emission end faces 8br, 8bg, and 8bb, respectively. The light receiving elements 12a to 1 2c are arranged corresponding to the respective interference filters 1 1 a to 1 1 c. The interference filter 11a has a filter characteristic such that red (R) light among the light beams emitted from the exit end face 8br penetrates, and the interference filter 11b has such that it exits from the exit end face 8bg. Among the beams, the green (G) light will penetrate the filter characteristics, and the interference filter 1 1 c has such that the blue (B) light from the light beam exiting the exit end face 8 bb will penetrate. Filter characteristics. The light-receiving element 12a outputs a photoelectric conversion signal based on the light passing through the red band t of the interference filter 11a, and the light-receiving element 12b outputs a photoelectric conversion signal based on the light passing through the green wavelength band of the interference filter 11b. The light-receiving element 12c outputs a photoelectric conversion signal based on the light having passed through the blue wavelength band of the interference filter lic, and each photoelectric conversion signal is input to the calculation circuit 1 and other measurement circuits, and the measurement circuit is excellent. Color characteristics such as degree, brightness, and chromatic aberration. The field of view aperture 13' for defining the size of the area to be measured is provided on the incident end surface 8a of the light guide 8, whereby excess light from the area to be measured is shielded from light. Further, the size of the field stop 13 , that is, the size of the incident end face 8 a of the light guide bodies 8 -11 - 201003048 is set to be larger than the size of the aperture stop 6 , whereby the incident end face of the light guide body 8 is opposed to The maximum incident angle αΐ of each of the light beams incident on the incident end surface 8a when the aperture stop 6 is disposed is 8a, and is incident when the incident end surface 8a of the light guide 8 is disposed at the rear focus position f2' of the second lens 7. The maximum incident angle ct2 of each of the light beams incident on the end face 8a can be moderated. As a result, even when the interference filter 1 1 a to 1 1 C having a high transmittance is used, the wavelength of the light can be prevented. Transient in the short wavelength direction to accurately determine color characteristics. Further, when the incident end surface 8a is intentionally placed at the position of the aperture stop 6, the maximum incident end angle α1 of the image forming light beam incident on the incident end surface 8a is stored and propagates to the exit end faces 8br to 8bb to be emitted. Therefore, when the interference optical filters 1 1 a to 1 1 c are used to constitute the optical system for measurement, it is necessary to lengthen the focal length of the first lens 5 in order to reduce the maximum incident angle α 1 and also to the light guide 8 . Since the incident end surface 8a is thus increased, the light guide 8 needs to have a sufficient length, and it is necessary to lengthen the entire length of the measuring optical system. However, in the embodiment of the present invention, the first lens 5 and the second lens 7 are used. The measuring optical system is configured by a telecentric optical system, and the maximum incident angle α2 of the image forming light beam incident on the incident end surface 8a through the second lens 7 is moderated from the maximum incident angle αΐ, so that it is not necessary. The length of the optical system for measurement is lengthened, and it can be configured in a compact manner. Ideally, the area of the aperture stop 6 is S1, and the area of the incident end face 8a of the light guide body 8, that is, the area of the field stop diaphragm 13 is S2, so that the product of the sine of the maximum incident angle αΐ of the aperture stop 6 and the area S1 is made. Sl.sino: -12- 201003048 1, which is equal to the product S2·sin α2 of the sine of the maximum incident angle "2" and the area S2, and the first lens 5 and the second lens 7' are disposed at the same time. The measurement area and the incident end surface 8a are optically conjugated with the first lens 5 and the second lens 7 interposed therebetween, and the incident end surface 8a is preferably disposed to the second lens 7. As described above, in the embodiment of the present invention, the light-receiving elements 12a to 12c are designed to face the interference filters 11a to 11c directly, but as shown in Fig. 4, at the exit end faces 8br to 8bb. Between the interference filters 1 la to 1 lc, a condensing lens 14 ′ having a positive refractive power that condenses the light beams emitted from the exit end faces 8 Br 8 bb is disposed so as to pass through a portion constituting the light receiving portion. The light beams of the interference filters 11a to 11c are converged in the light receiving elements 12a to 12c, and the light sensitivity can be further improved. According to the embodiment of the present invention, since the detection sensitivity of the weak light can be enhanced, the effect of improving the black measurement sensitivity in the measurement area can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS [Fig. 1] An explanatory view of a schematic diagram of an optical system for measurement of the present invention. Fig. 2 is a plan view showing the positional relationship of the exit end faces shown in Fig. 1. Fig. 3 is a perspective view showing a schematic view of an example of a fiber bundle according to the present invention. Fig. 4 is an explanatory view showing a pattern of another example of the optical system for measurement according to the present invention - 13 - 201003048. [Description of main component symbols] 1 : Liquid crystal panel 2 : Optical system for measurement 3 : Cylinder 4 : Frame 5 : First lens 6 : Open aperture 7 : Second lens 8 : Light guide 9 : Light receiving means 1 0 : Calculation circuit 1 3 : Field of view pupil 1 4 : Condenser lens 1 1 a to 1 1 c : Interference filter 8 br ' 8 bg ' 8bb: Outlet end face 12a to 12c: Light receiving element 1 a : Display surface 3 a : apex 8 a : incident end face Ο 1, Ο 2, Ο 3 : center position
Pal〜Pa3 :從點a入射至第1透鏡5之光束 Pbl〜Pb3 :從點b入射至第1透鏡5之光束 -14- 201003048Pal to Pa3: light beam incident from the point a to the first lens 5 Pb1 to Pb3: light beam incident from the point b to the first lens 5 -14- 201003048
Pci fl ： f Γ f2 ： f2' 〜Pc3 :從點c入射至第1透鏡5之光束 前側焦點位置 :後側焦點位置 前側焦點位置 =後側焦點位置 -15-Pci fl : f Γ f2 : f2' to Pc3 : light beam incident from the point c to the first lens 5 front side focus position: rear side focus position front side focus position = rear side focus position -15-