{"id":1597,"date":"2026-03-05T16:26:08","date_gmt":"2026-03-05T15:26:08","guid":{"rendered":"https:\/\/eltra.bfenterprise.it\/encoder-pedia\/cose-lencoder-ottico\/"},"modified":"2026-04-02T11:43:41","modified_gmt":"2026-04-02T09:43:41","slug":"what-is-an-optical-encoder","status":"publish","type":"page","link":"https:\/\/eltra.bfenterprise.it\/en\/encoder-pedia\/what-is-an-optical-encoder\/","title":{"rendered":"What is an optical encoder?"},"content":{"rendered":"<p>The most widespread encoders use the\u00a0<strong>optical<\/strong>\u00a0(or photoelectric) technology to detect signals; this differentiates in two main scanning methods: the transmissive and the reflective one.<\/p>\n<h4>Transmissive optical scanning<\/h4>\n<p>In the\u00a0<strong>transmissive optical encoder<\/strong>, the scan system is based on the rotation of a graduated disc &#8211; or\u00a0<a title=\"Encoder code wheel\" href=\"https:\/\/eltra.bfenterprise.it\/en\/encoder-pedia\/what-is-the-encoder-code-wheel\/\" target=\"_blank\" rel=\"noopener\">code wheel<\/a>\u00a0&#8211; \u00a0patterned with alternating opaque and clear (transparent) segments; the code wheel is illuminated by an infrared light source positioned perpendicularly to the sensor. The disc beams its image on the surface of several receivers, opportunely masked by another grid (called \u201ccollimator\u201d) with the same pitch as the other. The receivers have the task to sense the variations of light that take place during the rotation of the disc, converting them into corresponding electric pulses. In linear transducers the operating principle is similar, with the difference that the motion is detected on a linear reading system.<\/p>\n<figure id=\"attachment_378\" aria-describedby=\"caption-attachment-378\" style=\"width: 300px\" class=\"wp-caption alignleft\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-378 size-medium\" src=\"https:\/\/eltra.bfenterprise.it\/wp-content\/uploads\/2026\/03\/incrementale-ottico-300x294.jpg\" alt=\"Encoder ottico incrementale\" width=\"300\" height=\"294\" srcset=\"https:\/\/eltra.bfenterprise.it\/wp-content\/uploads\/2026\/03\/incrementale-ottico-300x294.jpg 300w, https:\/\/eltra.bfenterprise.it\/wp-content\/uploads\/2026\/03\/incrementale-ottico.jpg 554w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><figcaption id=\"caption-attachment-378\" class=\"wp-caption-text\">Incremental optical encoder<\/figcaption><\/figure>\n<figure id=\"attachment_379\" aria-describedby=\"caption-attachment-379\" style=\"width: 300px\" class=\"wp-caption alignleft\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-379 size-medium\" src=\"https:\/\/eltra.bfenterprise.it\/wp-content\/uploads\/2026\/03\/Disegno-Encoder-Assoluto-300x252.jpg\" alt=\"Encoder ottico assoluto\" width=\"300\" height=\"252\" srcset=\"https:\/\/eltra.bfenterprise.it\/wp-content\/uploads\/2026\/03\/Disegno-Encoder-Assoluto-300x252.jpg 300w, https:\/\/eltra.bfenterprise.it\/wp-content\/uploads\/2026\/03\/Disegno-Encoder-Assoluto.jpg 560w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><figcaption id=\"caption-attachment-379\" class=\"wp-caption-text\">Absolute optical encoder<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<h4>Reflective optical scanning<\/h4>\n<p>The\u00a0<strong>reflective optical system<\/strong>\u00a0is also based on the photoelectric scanning of a code wheel, but in this type of technology the light source and the receiver are in the same surface mount package: the light source illuminates the code wheel formed by darker segments alternated with reflective ones, where the light is reflected and detected by the sensor (receiver), which will transform the variations in corresponding pulses, as per the transmissive system. This type of reading allows reducing the size of the device while maintaining its performances; it\u2019s an ideal solution for those applications that require miniaturized encoders with a high resolution.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The most widespread encoders use the\u00a0optical\u00a0(or photoelectric) technology to detect signals; this differentiates in two [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":721,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"footnotes":""},"class_list":["post-1597","page","type-page","status-publish","hentry"],"acf":[],"_links":{"self":[{"href":"https:\/\/eltra.bfenterprise.it\/en\/wp-json\/wp\/v2\/pages\/1597","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/eltra.bfenterprise.it\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/eltra.bfenterprise.it\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/eltra.bfenterprise.it\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/eltra.bfenterprise.it\/en\/wp-json\/wp\/v2\/comments?post=1597"}],"version-history":[{"count":3,"href":"https:\/\/eltra.bfenterprise.it\/en\/wp-json\/wp\/v2\/pages\/1597\/revisions"}],"predecessor-version":[{"id":1637,"href":"https:\/\/eltra.bfenterprise.it\/en\/wp-json\/wp\/v2\/pages\/1597\/revisions\/1637"}],"up":[{"embeddable":true,"href":"https:\/\/eltra.bfenterprise.it\/en\/wp-json\/wp\/v2\/pages\/721"}],"wp:attachment":[{"href":"https:\/\/eltra.bfenterprise.it\/en\/wp-json\/wp\/v2\/media?parent=1597"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}