JPH04229824A - Fluorescent lamp lighting device - Google Patents

Fluorescent lamp lighting device

Info

Publication number
JPH04229824A
JPH04229824A JP2408492A JP40849290A JPH04229824A JP H04229824 A JPH04229824 A JP H04229824A JP 2408492 A JP2408492 A JP 2408492A JP 40849290 A JP40849290 A JP 40849290A JP H04229824 A JPH04229824 A JP H04229824A
Authority
JP
Japan
Prior art keywords
fluorescent lamp
period
circuit
light
pulse width
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP2408492A
Other languages
Japanese (ja)
Inventor
Yoshiaki Hara
Original Assignee
Toshiba Lighting & Technol Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Toshiba Lighting & Technol Corp filed Critical Toshiba Lighting & Technol Corp
Priority to JP2408492A priority Critical patent/JPH04229824A/en
Publication of JPH04229824A publication Critical patent/JPH04229824A/en
Pending legal-status Critical Current

Links

Abstract

PURPOSE:To provide accurate photometry without being affected by a quantity of light of a fluorescent lamp by carrying out the photometry of the light quantity around a liquid crystal display within a turn-off period of the fluorescent lamp. CONSTITUTION:An external light detecting circuit 104 feeds a pulse width control circuit 105 with an output signal conformed to a quantity of ambient light, and outputs a pulse of pulse width conformed to the output signal. With an of-off period of this pulse width, a chopper circuit 102 makes a direct current of a DC power source 101 intermit, further it converts the direct current into an alternate current of yet higher frequency at an inverter circuit 10 at the next stage, thereby turning on or off a fluorescent lamp 106 according to the on-off period of the chopper circuit 102. Accordingly, during the lighting of the fluorescent lamp 106 by a control means, the external light detecting circuit 104 will not measure the quantity of ambient light, thus this circuit 104 measures the quantity of ambient light accurately within the off period of the chopper circuit 102, namely, within the turn-off period of the fluorescent lamp 106.
JP2408492A 1990-12-27 1990-12-27 Fluorescent lamp lighting device Pending JPH04229824A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2408492A JPH04229824A (en) 1990-12-27 1990-12-27 Fluorescent lamp lighting device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2408492A JPH04229824A (en) 1990-12-27 1990-12-27 Fluorescent lamp lighting device

Publications (1)

Publication Number Publication Date
JPH04229824A true JPH04229824A (en) 1992-08-19

Family

ID=18517942

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2408492A Pending JPH04229824A (en) 1990-12-27 1990-12-27 Fluorescent lamp lighting device

Country Status (1)

Country Link
JP (1) JPH04229824A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007072243A (en) * 2005-09-08 2007-03-22 Sanyo Epson Imaging Devices Corp Illuminance detecting method, luminance control method, electrooptical device, and electronic equipment
JP2007179000A (en) * 2005-12-01 2007-07-12 Hitachi Displays Ltd Liquid crystal display device and display device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007072243A (en) * 2005-09-08 2007-03-22 Sanyo Epson Imaging Devices Corp Illuminance detecting method, luminance control method, electrooptical device, and electronic equipment
JP2007179000A (en) * 2005-12-01 2007-07-12 Hitachi Displays Ltd Liquid crystal display device and display device

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