{"id":1661,"date":"2026-06-03T10:56:16","date_gmt":"2026-06-03T01:56:16","guid":{"rendered":"https:\/\/www.san-eielectric.co.jp\/am\/?page_id=1661"},"modified":"2026-06-03T11:40:31","modified_gmt":"2026-06-03T02:40:31","slug":"angular-characteristics-of-solar-simulators","status":"publish","type":"page","link":"https:\/\/www.san-eielectric.co.jp\/am\/en\/solar-simulator-technology\/angular-characteristics-of-solar-simulators\/","title":{"rendered":"Angular Characteristics of Solar Simulators"},"content":{"rendered":"\n<div id=\"anchor-00\" class=\"wp-block-group has-global-padding is-layout-constrained wp-container-core-group-is-layout-155d5985 wp-block-group-is-layout-constrained\" style=\"border-width:1px;margin-top:var(--wp--preset--spacing--30);margin-bottom:var(--wp--preset--spacing--30);padding-top:var(--wp--preset--spacing--20);padding-right:var(--wp--preset--spacing--20);padding-bottom:var(--wp--preset--spacing--20);padding-left:var(--wp--preset--spacing--20)\">\n<h2 class=\"wp-block-heading has-large-font-size\"><strong>INDEX<\/strong><\/h2>\n\n\n\n<div class=\"wp-block-group is-layout-grid wp-container-core-group-is-layout-628aea67 wp-block-group-is-layout-grid\" style=\"margin-top:var(--wp--preset--spacing--20);margin-bottom:var(--wp--preset--spacing--20);padding-top:0;padding-right:0;padding-bottom:0;padding-left:0\">\n<p class=\"has-medium-font-size wp-block-paragraph\"><a href=\"https:\/\/www.san-eielectric.co.jp\/am\/en\/solar-simulator-technology\/angular-characteristics-of-solar-simulators\/#anchor-01\">1. Why SAN-EI Provides Angular Information<\/a><\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\"><a href=\"https:\/\/www.san-eielectric.co.jp\/am\/en\/solar-simulator-technology\/angular-characteristics-of-solar-simulators\/#anchor-02\">2. SAN-EI\u2019s Basic Policy<\/a><\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\"><a href=\"https:\/\/www.san-eielectric.co.jp\/am\/en\/solar-simulator-technology\/angular-characteristics-of-solar-simulators\/#anchor-03\">3. Transition from Conventional CHA and DA Indications<\/a><\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\"><a href=\"https:\/\/www.san-eielectric.co.jp\/am\/en\/solar-simulator-technology\/angular-characteristics-of-solar-simulators\/#anchor-04\">4. Main Angular Specifications<br><\/a><\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\"><a href=\"https:\/\/www.san-eielectric.co.jp\/am\/en\/solar-simulator-technology\/angular-characteristics-of-solar-simulators\/#anchor-05\">5. Measurement Method<\/a><\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\"><a href=\"https:\/\/www.san-eielectric.co.jp\/am\/en\/solar-simulator-technology\/angular-characteristics-of-solar-simulators\/#anchor-06\">6. Calculation Method<\/a><\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\"><a href=\"https:\/\/www.san-eielectric.co.jp\/am\/en\/solar-simulator-technology\/angular-characteristics-of-solar-simulators\/#anchor-07\">7. Important Notes<\/a><\/p>\n\n\n\n<p class=\"has-medium-font-size wp-container-content-574e1f9d wp-block-paragraph\"><a href=\"https:\/\/www.san-eielectric.co.jp\/am\/en\/solar-simulator-technology\/angular-characteristics-of-solar-simulators\/#anchor-08\">8. SAN-EI\u2019s Position<\/a><\/p>\n<\/div>\n<\/div>\n\n\n\n<h2 id=\"anchor-01\" class=\"wp-block-heading has-base-color has-contrast-background-color has-text-color has-background has-link-color has-large-font-size wp-elements-dfad7184efb710a34817a5af5f9d641f\" style=\"padding-top:var(--wp--preset--spacing--20);padding-right:var(--wp--preset--spacing--20);padding-bottom:var(--wp--preset--spacing--20);padding-left:var(--wp--preset--spacing--20)\">1. Why SAN-EI Provides Angular Information<\/h2>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Solar simulator performance is generally evaluated by the following key items:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li class=\"has-medium-font-size\">Spectral irradiance distribution<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Irradiance level<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Spatial non-uniformity over the effective irradiation area<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Temporal instability<\/li>\n<\/ul>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">These are essential parameters for evaluating the quantity, distribution, and stability of simulated sunlight.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">However, in some applications, the angle at which light enters the sample surface may also affect the test result.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">This is especially important in applications such as:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li class=\"has-medium-font-size\">Fine pattern exposure<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Photoresist evaluation<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Optical material evaluation<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Evaluation of samples with angular dependence<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Thin films, multilayer films, and anti-reflection coatings<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Small-area devices requiring well-defined irradiation conditions<\/li>\n<\/ul>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">For this reason, SAN-EI provides angular information when it is useful for understanding the irradiation conditions more accurately.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Angular characteristics do not replace the basic performance items of a solar simulator.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">They are additional technical information that helps users understand the nature of the light reaching the sample surface.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">SAN-EI\u2019s purpose is not to make the equipment appear better by adding more specifications.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Our purpose is to help users judge whether the irradiation conditions are suitable for their specific test purpose.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Therefore, in addition to spectral characteristics, spatial non-uniformity, and temporal instability, SAN-EI also provides angular information when it is relevant to the application.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\"><a href=\"https:\/\/www.san-eielectric.co.jp\/am\/en\/solar-simulator-technology\/angular-characteristics-of-solar-simulators\/#anchor-00\">Return to INDEX<\/a><\/p>\n\n\n\n<h2 id=\"anchor-02\" class=\"wp-block-heading has-base-color has-contrast-background-color has-text-color has-background has-link-color has-large-font-size wp-elements-e1a615feb12975615bd6a69c7769ec5e\" style=\"padding-top:var(--wp--preset--spacing--20);padding-right:var(--wp--preset--spacing--20);padding-bottom:var(--wp--preset--spacing--20);padding-left:var(--wp--preset--spacing--20)\">2. SAN-EI\u2019s Basic Policy<\/h2>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">SAN-EI regards angular information as supplementary information for correct use and correct evaluation.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Angular values should not be shown as isolated numbers.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">The meaning of an angular specification depends on the definition, measurement position, measurement range, and calculation method.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">For this reason, SAN-EI provides angular specifications together with the following information whenever possible:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li class=\"has-medium-font-size\">What the value represents<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Where the value was measured<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Which part of the light was evaluated<\/li>\n\n\n\n<li class=\"has-medium-font-size\">How the value was calculated<\/li>\n\n\n\n<li class=\"has-medium-font-size\">For what purpose the value is useful<\/li>\n<\/ul>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">This approach helps users understand and compare angular characteristics without misunderstanding.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\"><a href=\"https:\/\/www.san-eielectric.co.jp\/am\/en\/solar-simulator-technology\/angular-characteristics-of-solar-simulators\/#anchor-00\">Return to INDEX<\/a><\/p>\n\n\n\n<h2 id=\"anchor-03\" class=\"wp-block-heading has-base-color has-contrast-background-color has-text-color has-background has-link-color has-large-font-size wp-elements-3c7ef9be307f67fde624aa33f988affd\" style=\"padding-top:var(--wp--preset--spacing--20);padding-right:var(--wp--preset--spacing--20);padding-bottom:var(--wp--preset--spacing--20);padding-left:var(--wp--preset--spacing--20)\">3. Transition from Conventional CHA and DA Indications<\/h2>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">SAN-EI has previously provided angular values such as CHA (Collimation Half Angle) and DA (Declination Angle) in response to user requests.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">These indications have been used mainly to satisfy specific user specifications or application requirements.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">However, angular terms such as CHA and DA may be interpreted differently depending on the field, application, or user.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Even when the same term is used, the meaning of the value may change depending on the measurement method, measurement plane, evaluation range, and calculation method.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Therefore, SAN-EI is moving toward a clearer method of displaying angular specifications.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">In the new approach, angular values will be shown together with their definitions, measurement conditions, and calculation methods.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">This does not mean that SAN-EI will stop supporting conventional CHA and DA indications.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">When users require CHA or DA, SAN-EI will continue to provide them as necessary.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">However, SAN-EI will provide these values with clear definitions and conditions, rather than showing the numbers alone.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Our intention is not to reject the conventional indications, but to make angular information more accurate, more reproducible, and easier to understand.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\"><a href=\"https:\/\/www.san-eielectric.co.jp\/am\/en\/solar-simulator-technology\/angular-characteristics-of-solar-simulators\/#anchor-00\">Return to INDEX<\/a><\/p>\n\n\n\n<h2 id=\"anchor-04\" class=\"wp-block-heading has-base-color has-contrast-background-color has-text-color has-background has-link-color has-large-font-size wp-elements-dbd2621ad6fa96e890b0b56cfefc0671\" style=\"padding-top:var(--wp--preset--spacing--20);padding-right:var(--wp--preset--spacing--20);padding-bottom:var(--wp--preset--spacing--20);padding-left:var(--wp--preset--spacing--20)\">4. Main Angular Specifications<\/h2>\n\n\n\n<h3 class=\"wp-block-heading has-contrast-color has-text-color has-link-color has-large-font-size wp-elements-9c4ae764a2cb0ee6ef44e538dd0fcf41\" style=\"border-width:1px;padding-top:5px;padding-right:var(--wp--preset--spacing--20);padding-bottom:5px;padding-left:var(--wp--preset--spacing--20)\">4.1 Incident Angle<\/h3>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">The incident angle is the angle at which light enters the sample surface.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Normally, the direction perpendicular to the sample surface is defined as 0\u00b0.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">The incident angle shows how far the incoming light is inclined from this perpendicular direction.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">The incident angle may affect reflection, absorption, transmission, and interference at the sample surface.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">This is especially important for thin films, multilayer films, optical coatings, solar cells, and photoresists.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">For this reason, incident angle information can be useful for confirming the reproducibility and comparability of test results.<\/p>\n\n\n\n<h3 class=\"wp-block-heading has-contrast-color has-text-color has-link-color has-large-font-size wp-elements-97f731a1b3f305f65b392e5d46b81705\" style=\"border-width:1px;padding-top:5px;padding-right:var(--wp--preset--spacing--20);padding-bottom:5px;padding-left:var(--wp--preset--spacing--20)\">4.2 Optical Axis Angle<\/h3>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">The optical axis angle indicates how much the central direction of the irradiation light is tilted from the normal direction of the sample surface.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Ideally, the central direction of the light should be perpendicular to the sample surface.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">In actual optical systems, however, the optical axis may be slightly tilted due to the lamp, reflector, lens, filter, working distance, or mechanical alignment.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Displaying the optical axis angle helps users understand how well the central direction of the irradiation light is aligned with the sample plane.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">This information is especially important for precise positioning, fine pattern exposure, and evaluation of samples with angular dependence.<\/p>\n\n\n\n<h3 class=\"wp-block-heading has-contrast-color has-text-color has-link-color has-large-font-size wp-elements-98db2c93b449cb60f3fad7bdd8c836cd\" style=\"border-width:1px;padding-top:5px;padding-right:var(--wp--preset--spacing--20);padding-bottom:5px;padding-left:var(--wp--preset--spacing--20)\">4.3 Divergence Angle<\/h3>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">The divergence angle indicates how widely the irradiation light spreads in angle when it reaches the sample surface.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">The light from a solar simulator is not perfectly parallel.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Because of the lamp source, reflector, lens system, filter, and working distance, the light reaches the sample surface with a certain angular spread.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">The divergence angle is used to describe this angular spread.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">A smaller divergence angle means that the light is closer to parallel light.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">A larger divergence angle means that light enters the sample from a wider range of directions.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">However, a smaller divergence angle is not always better.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">For applications requiring a wide and uniform irradiation area, a certain angular spread may be necessary.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">For fine pattern exposure or samples with strong angular dependence, a smaller angular spread may be more important.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Therefore, the divergence angle should not be used as a simple ranking value.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">It should be evaluated in relation to the intended application.<\/p>\n\n\n\n<h3 class=\"wp-block-heading has-contrast-color has-text-color has-link-color has-large-font-size wp-elements-560b5d6014c2604e13f7b5e6b7b3fc77\" style=\"border-width:1px;padding-top:5px;padding-right:var(--wp--preset--spacing--20);padding-bottom:5px;padding-left:var(--wp--preset--spacing--20)\">4.4 Half-Angle and Full Width at Half Maximum<\/h3>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">The half-angle is the angle at which the angular intensity falls to 50% of the maximum intensity.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">It is used to understand how concentrated the main part of the irradiation light is around the central direction.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">In some cases, the value is shown as a half-angle from the center.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">In other cases, it is shown as the full width at half maximum.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">For example:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li class=\"has-medium-font-size\">Half-angle: \u00b12.5\u00b0<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Full width at half maximum: 5.0\u00b0<\/li>\n<\/ul>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">These may describe the same angular distribution, but the expression is different.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Therefore, when comparing values, it is important to confirm whether the value is shown as a half-angle or as a full width.<\/p>\n\n\n\n<h3 class=\"wp-block-heading has-contrast-color has-text-color has-link-color has-large-font-size wp-elements-ec1e39b459834a97b0525cebf7b99032\" style=\"border-width:1px;padding-top:5px;padding-right:var(--wp--preset--spacing--20);padding-bottom:5px;padding-left:var(--wp--preset--spacing--20)\">4.5 CHA (Collimation Half Angle)<\/h3>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">CHA is one of the angular indications that SAN-EI has provided in response to user requests.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">It has been used to express angular characteristics in a simple form for specific applications.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">However, the definition of CHA may vary depending on the user or technical field.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Therefore, when SAN-EI provides CHA, we will also clarify the definition, measurement position, evaluation range, and calculation method.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">CHA will continue to be supported when it is required by users or existing specifications.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">At the same time, SAN-EI will not rely only on CHA.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">When necessary, CHA will be explained together with angular distribution, optical axis angle, divergence angle, or other defined angular information.<\/p>\n\n\n\n<h3 class=\"wp-block-heading has-contrast-color has-text-color has-link-color has-large-font-size wp-elements-8b21604906a50dbd532d04c4bbdf56e3\" style=\"border-width:1px;padding-top:5px;padding-right:var(--wp--preset--spacing--20);padding-bottom:5px;padding-left:var(--wp--preset--spacing--20)\">4.6 DA (Declination Angle)<\/h3>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">DA is also one of the angular indications that SAN-EI has provided according to user requirements.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">DA is used to describe the angular deviation of the irradiation light from a defined reference direction, such as the optical axis or the normal direction of the sample plane.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">However, as with CHA, the meaning of DA may vary depending on the definition and measurement method.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Therefore, when SAN-EI provides DA, we will clarify the measurement position, measurement plane, angular range, and calculation method.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">DA will continue to be supported for compatibility with conventional user requirements.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">At the same time, SAN-EI will gradually move toward clearer and more reproducible angular specifications.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\"><a href=\"https:\/\/www.san-eielectric.co.jp\/am\/en\/solar-simulator-technology\/angular-characteristics-of-solar-simulators\/#anchor-00\">Return to INDEX<\/a><\/p>\n\n\n\n<h2 id=\"anchor-05\" class=\"wp-block-heading has-base-color has-contrast-background-color has-text-color has-background has-link-color has-large-font-size wp-elements-81d8e249dec65c148dc04d5833d3962b\" style=\"padding-top:var(--wp--preset--spacing--20);padding-right:var(--wp--preset--spacing--20);padding-bottom:var(--wp--preset--spacing--20);padding-left:var(--wp--preset--spacing--20)\">5. Measurement Method<\/h2>\n\n\n\n<h3 class=\"wp-block-heading has-contrast-color has-text-color has-link-color has-large-font-size wp-elements-9efee15280cc77beeaac18b651252260\" style=\"border-width:1px;padding-top:5px;padding-right:var(--wp--preset--spacing--20);padding-bottom:5px;padding-left:var(--wp--preset--spacing--20)\">5.1 Measurement Position<\/h3>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Angular characteristics are measured at the sample plane, normally at the specified working distance.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">The working distance is the position where the sample is placed and where the optical performance is evaluated.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">If the working distance changes, the irradiation area, irradiance, spatial non-uniformity, and angular distribution may also change.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Therefore, when angular specifications are shown, the measurement position must be clearly stated.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Typical information includes:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li class=\"has-medium-font-size\">Measurement position<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Working distance<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Measurement plane<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Effective irradiation area<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Measurement point or points<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Reference direction for angle measurement<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading has-contrast-color has-text-color has-link-color has-large-font-size wp-elements-f2b8c5dfd20da6e352e155a43c99ae05\" style=\"border-width:1px;padding-top:5px;padding-right:var(--wp--preset--spacing--20);padding-bottom:5px;padding-left:var(--wp--preset--spacing--20)\">5.2 Measurement Target<\/h3>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">The measurement target is the angular distribution of the irradiation light at the sample plane.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Depending on the purpose, the measurement may include:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li class=\"has-medium-font-size\">Angular distribution at the center of the effective irradiation area<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Angular distribution at multiple points within the effective irradiation area<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Tilt of the optical axis<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Angular spread of the light<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Ratio of light included within a specified angular range<\/li>\n<\/ul>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">A single measurement point may not fully represent the angular characteristics over the entire effective irradiation area.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">For high-precision applications, measurements at multiple points may be required.<\/p>\n\n\n\n<h3 class=\"wp-block-heading has-contrast-color has-text-color has-link-color has-large-font-size wp-elements-97d1e4cc887e0818d99236de00b82413\" style=\"border-width:1px;padding-top:5px;padding-right:var(--wp--preset--spacing--20);padding-bottom:5px;padding-left:var(--wp--preset--spacing--20)\">5.3 Measurement Equipment<\/h3>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Angular characteristics may be measured using suitable instruments or measurement systems, such as:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li class=\"has-medium-font-size\">Angular distribution measurement equipment<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Goniometer-based measurement system<\/li>\n\n\n\n<li class=\"has-medium-font-size\">A slit and sensor measurement system<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Camera-based optical axis confirmation system<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Dedicated fixtures for incident angle measurement<\/li>\n<\/ul>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">The type of measurement equipment affects the angular resolution, measurable range, and interpretation of the result.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Therefore, SAN-EI records the measurement equipment and conditions when angular specifications are provided.<\/p>\n\n\n\n<h3 class=\"wp-block-heading has-contrast-color has-text-color has-link-color has-large-font-size wp-elements-82f00d41ab099ea761c7f088f23e0869\" style=\"border-width:1px;padding-top:5px;padding-right:var(--wp--preset--spacing--20);padding-bottom:5px;padding-left:var(--wp--preset--spacing--20)\">5.4 Measurement Conditions<\/h3>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">The following conditions should be recorded when angular characteristics are measured:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li class=\"has-medium-font-size\">Model name<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Lamp type<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Lamp current or operating condition<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Filter configuration<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Working distance<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Measurement plane<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Effective irradiation area<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Measurement point<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Measurement equipment<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Angular measurement range<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Angular resolution<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Measurement environment<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Measurement date<\/li>\n<\/ul>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">By recording these conditions, the reproducibility and comparability of angular information can be improved.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\"><a href=\"https:\/\/www.san-eielectric.co.jp\/am\/en\/solar-simulator-technology\/angular-characteristics-of-solar-simulators\/#anchor-00\">Return to INDEX<\/a><\/p>\n\n\n\n<h2 id=\"anchor-06\" class=\"wp-block-heading has-base-color has-contrast-background-color has-text-color has-background has-link-color has-large-font-size wp-elements-4af36fcb189e8a13fea9cf3bdc7e398e\" style=\"padding-top:var(--wp--preset--spacing--20);padding-right:var(--wp--preset--spacing--20);padding-bottom:var(--wp--preset--spacing--20);padding-left:var(--wp--preset--spacing--20)\">6. Calculation Method<\/h2>\n\n\n\n<h3 class=\"wp-block-heading has-contrast-color has-text-color has-link-color has-large-font-size wp-elements-86c5839217e70c38fd9214732d9d7a1a\" style=\"border-width:1px;padding-top:5px;padding-right:var(--wp--preset--spacing--20);padding-bottom:5px;padding-left:var(--wp--preset--spacing--20)\">6.1 Optical Axis Angle<\/h3>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">The optical axis angle is calculated by determining the central direction of the measured angular distribution.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">The angle between this central direction and the normal direction of the sample surface is then shown as the optical axis angle.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Example:<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Optical axis angle: 0.8\u00b0<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">This means that the central direction of the irradiation light is tilted by 0.8\u00b0 from the normal direction of the sample surface.<\/p>\n\n\n\n<h3 class=\"wp-block-heading has-contrast-color has-text-color has-link-color has-large-font-size wp-elements-5601c11f65491e254ed1dad216db267a\" style=\"border-width:1px;padding-top:5px;padding-right:var(--wp--preset--spacing--20);padding-bottom:5px;padding-left:var(--wp--preset--spacing--20)\">6.2 Divergence Angle<\/h3>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">The divergence angle is calculated from the angular spread of the measured light distribution. Several methods may be used depending on the purpose, such as:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li class=\"has-medium-font-size\">The angular range where the intensity is 50% or more of the maximum intensity<\/li>\n\n\n\n<li class=\"has-medium-font-size\">The angular range that includes a specified percentage of the total light<\/li>\n\n\n\n<li class=\"has-medium-font-size\">The angular range where the intensity exceeds a specified threshold<\/li>\n<\/ul>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">When SAN-EI shows a divergence angle, the calculation method will be stated.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Example:<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Divergence angle: \u00b13.0\u00b0<br>Condition: angular range where the intensity is 50% or more of the maximum intensity<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">This means that the main part of the light distribution is within \u00b13.0\u00b0 from the central direction under the stated condition.<\/p>\n\n\n\n<h3 class=\"wp-block-heading has-contrast-color has-text-color has-link-color has-large-font-size wp-elements-53d0ad4ceff84f96b856fd8ebe31fcec\" style=\"border-width:1px;padding-top:5px;padding-right:var(--wp--preset--spacing--20);padding-bottom:5px;padding-left:var(--wp--preset--spacing--20)\">6.3 Half-Angle<\/h3>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">The half-angle is calculated by finding the angle where the angular intensity becomes 50% of the maximum intensity.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">SAN-EI will clarify whether the value is shown as a half-angle or as a full width.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Example:<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Half-angle: \u00b12.5\u00b0<br>or<br>Full width at half maximum: 5.0\u00b0<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">The numerical meaning is different depending on the expression.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Therefore, the definition must be confirmed before comparing values.<\/p>\n\n\n\n<h3 class=\"wp-block-heading has-contrast-color has-text-color has-link-color has-large-font-size wp-elements-d9e4b48aca6a7d8f9d6a5031c899d200\" style=\"border-width:1px;padding-top:5px;padding-right:var(--wp--preset--spacing--20);padding-bottom:5px;padding-left:var(--wp--preset--spacing--20)\">6.4 CHA (Collimation Half Angle) and DA (Declination Angle)<\/h3>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">When CHA or DA is provided, the calculation method will follow the user-specified definition or the conventional specification requested by the user.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">However, SAN-EI will also clarify the following information:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li class=\"has-medium-font-size\">Definition of CHA or DA<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Measurement position<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Measurement range<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Evaluation angle range<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Calculation method<\/li>\n\n\n\n<li class=\"has-medium-font-size\">Whether the value is shown as a half-angle or full width<\/li>\n<\/ul>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">This allows SAN-EI to maintain compatibility with conventional user requirements while avoiding misunderstanding.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\"><a href=\"https:\/\/www.san-eielectric.co.jp\/am\/en\/solar-simulator-technology\/angular-characteristics-of-solar-simulators\/#anchor-00\">Return to INDEX<\/a><\/p>\n\n\n\n<h2 id=\"anchor-07\" class=\"wp-block-heading has-base-color has-contrast-background-color has-text-color has-background has-link-color has-large-font-size wp-elements-1a3afbc6d9b10390f327c1b2f07c501a\" style=\"padding-top:var(--wp--preset--spacing--20);padding-right:var(--wp--preset--spacing--20);padding-bottom:var(--wp--preset--spacing--20);padding-left:var(--wp--preset--spacing--20)\">7. Important Notes<\/h2>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Angular characteristics depend on the measurement conditions.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Values measured with different working distances, different irradiation areas, different measurement methods, or different definitions cannot be compared directly.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">A smaller angular value is not always better.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">In some applications, a certain angular spread may be necessary to obtain a uniform irradiation area.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">In other applications, such as fine pattern exposure or evaluation of angular-dependent samples, a smaller angular spread may be preferred.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Therefore, angular specifications should not be used as simple ranking values.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">They should be used as technical information for judging whether the irradiation condition is suitable for the intended application.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">SAN-EI provides angular information to support correct understanding, correct use, and correct evaluation of solar simulators.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\"><a href=\"https:\/\/www.san-eielectric.co.jp\/am\/en\/solar-simulator-technology\/angular-characteristics-of-solar-simulators\/\">Return to INDEX<\/a><\/p>\n\n\n\n<h2 id=\"anchor-08\" class=\"wp-block-heading has-base-color has-contrast-background-color has-text-color has-background has-link-color has-large-font-size wp-elements-19b808e3386bd869ea38d63edded143b\" style=\"padding-top:var(--wp--preset--spacing--20);padding-right:var(--wp--preset--spacing--20);padding-bottom:var(--wp--preset--spacing--20);padding-left:var(--wp--preset--spacing--20)\">8. SAN-EI\u2019s Position<\/h2>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">SAN-EI will provide angular specifications as supplementary technical information when they are useful for the application.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">We will continue to support conventional CHA and DA indications when users require them.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">At the same time, we will gradually move toward clearer angular specifications with defined measurement conditions and calculation methods.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Our goal is to provide information that helps users understand the actual irradiation conditions at the sample plane.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">SAN-EI believes that solar simulator performance should not be explained only by isolated numerical values.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">It should be explained together with the measurement conditions, definitions, and purpose of use.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">Angular characteristics are one part of this approach.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\"><a href=\"https:\/\/www.san-eielectric.co.jp\/am\/en\/solar-simulator-technology\/angular-characteristics-of-solar-simulators\/\" data-type=\"page\" data-id=\"93\">Return to INDEX<\/a><\/p>\n\n\n\n<div class=\"wp-block-group has-global-padding is-layout-constrained wp-container-core-group-is-layout-155d5985 wp-block-group-is-layout-constrained\" style=\"border-width:1px;margin-top:var(--wp--preset--spacing--30);margin-bottom:var(--wp--preset--spacing--30);padding-top:var(--wp--preset--spacing--20);padding-right:var(--wp--preset--spacing--20);padding-bottom:var(--wp--preset--spacing--20);padding-left:var(--wp--preset--spacing--20)\">\n<h2 class=\"wp-block-heading has-large-font-size\"><strong>INDEX<\/strong><\/h2>\n\n\n\n<div class=\"wp-block-group is-layout-grid wp-container-core-group-is-layout-628aea67 wp-block-group-is-layout-grid\" style=\"margin-top:var(--wp--preset--spacing--20);margin-bottom:var(--wp--preset--spacing--20);padding-top:0;padding-right:0;padding-bottom:0;padding-left:0\">\n<p class=\"has-medium-font-size wp-block-paragraph\"><a href=\"https:\/\/www.san-eielectric.co.jp\/am\/en\/solar-simulator-technology\/angular-characteristics-of-solar-simulators\/#anchor-01\">1. Why SAN-EI Provides Angular Information<\/a><\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\"><a href=\"https:\/\/www.san-eielectric.co.jp\/am\/en\/solar-simulator-technology\/angular-characteristics-of-solar-simulators\/#anchor-02\">2. SAN-EI\u2019s Basic Policy<\/a><\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\"><a href=\"https:\/\/www.san-eielectric.co.jp\/am\/en\/solar-simulator-technology\/angular-characteristics-of-solar-simulators\/#anchor-03\">3. Transition from Conventional CHA and DA Indications<\/a><\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\"><a href=\"https:\/\/www.san-eielectric.co.jp\/am\/en\/solar-simulator-technology\/angular-characteristics-of-solar-simulators\/#anchor-04\">4. Main Angular Specifications<br><\/a><\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\"><a href=\"https:\/\/www.san-eielectric.co.jp\/am\/en\/solar-simulator-technology\/angular-characteristics-of-solar-simulators\/#anchor-05\">5. Measurement Method<\/a><\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\"><a href=\"https:\/\/www.san-eielectric.co.jp\/am\/en\/solar-simulator-technology\/angular-characteristics-of-solar-simulators\/#anchor-06\">6. Calculation Method<\/a><\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\"><a href=\"https:\/\/www.san-eielectric.co.jp\/am\/en\/solar-simulator-technology\/angular-characteristics-of-solar-simulators\/#anchor-07\">7. Important Notes<\/a><\/p>\n\n\n\n<p class=\"has-medium-font-size wp-container-content-574e1f9d wp-block-paragraph\"><a href=\"https:\/\/www.san-eielectric.co.jp\/am\/en\/solar-simulator-technology\/angular-characteristics-of-solar-simulators\/#anchor-08\">8. SAN-EI\u2019s Position<\/a><\/p>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>INDEX 1. Why SAN-EI Provides Angular Information 2. SAN-EI\u2019s Basic Policy 3. Transition from Conventional CHA  [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":93,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-1661","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.san-eielectric.co.jp\/am\/wp-json\/wp\/v2\/pages\/1661","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.san-eielectric.co.jp\/am\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.san-eielectric.co.jp\/am\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.san-eielectric.co.jp\/am\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.san-eielectric.co.jp\/am\/wp-json\/wp\/v2\/comments?post=1661"}],"version-history":[{"count":6,"href":"https:\/\/www.san-eielectric.co.jp\/am\/wp-json\/wp\/v2\/pages\/1661\/revisions"}],"predecessor-version":[{"id":1672,"href":"https:\/\/www.san-eielectric.co.jp\/am\/wp-json\/wp\/v2\/pages\/1661\/revisions\/1672"}],"up":[{"embeddable":true,"href":"https:\/\/www.san-eielectric.co.jp\/am\/wp-json\/wp\/v2\/pages\/93"}],"wp:attachment":[{"href":"https:\/\/www.san-eielectric.co.jp\/am\/wp-json\/wp\/v2\/media?parent=1661"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}