{"schema_version":"1.0","canonical_url":"https://patentable.app/patents/US-8474985","patent":{"patent_number":"US-8474985","title":"Projector lamp lighting device supplying AC current including low frequency region having current reduction waveform","assignee":null,"inventors":[],"filing_date":"2010-10-25T00:00:00.000Z","publication_date":"2013-07-02T00:00:00.000Z","cpc_codes":["H04N"],"num_claims":3,"abstract":"A discharge lamp lighting device includes a lamp current control portion that generates, in synchronization with an input video signal, a control signal for controlling polarity reversal of an AC current with a steady-state lighting frequency and an AC current with a low frequency, and a lamp driving portion that drives the discharge lamp based on the control signal that is output by the lamp current control portion. The lamp current control portion generates a control signal for a brightness reduction waveform with timing corresponding to polarity reversal of the AC current with the steady-state lighting frequency, and the lamp driving portion inserts a current reduction waveform into the AC current with the low frequency by decreasing a voltage applied to the discharge lamp based on the control signal for the brightness reduction waveform. It is possible to reduce flicker that could be perceived due to insertion of a period without a reduction of the projection light amount (a period without a polarity reversal at the low frequency) during repeated reductions of the projection light amount occurring at intervals of polarity reversal of the steady-state lighting frequency."},"analysis":{"summary":null,"layman_explanation":null,"technical_analysis":null,"business_analysis":null,"faqs":null,"topics":[],"tech_cluster":null},"seo":{"title":"Projector lamp lighting device supplying AC current including low frequency region having current reduction waveform","description":"A discharge lamp lighting device includes a lamp current control portion that generates, in synchronization with an input video signal, a control signal for controlling polarity reversal of an AC curr","keywords":[]},"attribution":{"source":"Patentable","source_url":"https://patentable.app","canonical_url":"https://patentable.app/patents/US-8474985","license":"CC-BY-4.0-like","license_terms":"AI-generated analysis on this page (summary, layman_explanation, technical_analysis, business_analysis, faqs) may be reused with attribution and a visible link back to the canonical URL above. Patent abstracts, claims, and bibliographic data are USPTO public domain.","required_link":"https://patentable.app/patents/US-8474985","citation_suggestion":"Patentable. \"Projector lamp lighting device supplying AC current including low frequency region having current reduction waveform\" (US-8474985). https://patentable.app/patents/US-8474985","copyright_holder":"Nomic Interactive Technology LLC"},"links":{"html":"https://patentable.app/patents/US-8474985","json":"https://patentable.app/api/llm-context/US-8474985","site":"https://patentable.app","llms_txt":"https://patentable.app/llms.txt"},"generated_at":"2026-05-30T14:06:21.308Z"}