PARTICLE MEASURING APPARATUS

• Main Authors: KONDO IKU, TABUCHI TAKUYA, KONDO SOTA, BANDO KAZUNA
• Format: Patent
• Language: English; Japanese
• Published: 26.07.2021
• Subjects: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASURING; PHYSICS; TESTING

To provide a technique which improves a particle diameter resolution.SOLUTION: First, an expander 21 expands irradiation light LI which is emitted by a light source 10, into a shape meeting a request of a DOE 22, makes the light into parallel light and makes the same incident to the DOE 22. Next, the DOE 22 shapes the incident irradiation light LI into a flat top beam of which a cross section at a focal position thereof has an elongated rectangular shape. Since high-order diffraction light is generated in a shaping step in the DOE 22, the shaped irradiation light LI is emitted from the DOE 22 to a focal point and, in addition, the high-order diffraction light is radially diverted. Three different slit plates 23-25 disposed between the DOE 22 and the focal point surely pass the shaped irradiation light LI while shielding the high-order diffraction light step by step. Since intensity distribution of light is substantially uniform in a detection region formed from the shaped irradiation light LI, the number of times of tracking diverting motion of particles (the number of frame images to be acquired) can be fixed regardless of passage position of particles, thereby improving a particle diameter resolution.SELECTED DRAWING: Figure 3 【課題】粒径分解能を向上させる技術の提供。【解決手段】先ず、エキスパンダ２１が、光源１０が出射した照射光ＬＩをＤＯＥ２２の要求を満たす形状に拡大し、平行光にしてＤＯＥ２２に入射させる。次に、ＤＯＥ２２が、入射した照射光ＬＩをその焦点位置における断面が細長い矩形状をなすフラットトップビームに整形する。ＤＯＥ２２における整形過程では高次回折光が生じるため、ＤＯＥ２２からは、整形された照射光ＬＩが焦点に向かって出射するのに加え、高次回折光が放射状に発散する。ＤＯＥ２２と焦点との間に配置された３枚の異なるスリット板２３〜２５は、高次回折光を段階的に遮蔽しつつ整形された照射光ＬＩを確実に通過させる。整形された照射光ＬＩにより形成される検出領域においては光の強度分布が略均一なため、粒子の拡散運動の追跡回数（フレーム画像の取得枚数）を粒子の通過位置に関わらず一定にすることができ、粒径分解能を向上できる。【選択図】図３