发明申请
- 专利标题: PHOTOMETRIC DEVICE
- 专利标题(中): 光学设备
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申请号: US12487287申请日: 2009-06-18
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公开(公告)号: US20090324244A1公开(公告)日: 2009-12-31
- 发明人: Jun KOYAMA , Seiko AMANO
- 申请人: Jun KOYAMA , Seiko AMANO
- 申请人地址: JP Atsugi-shi
- 专利权人: SEMICONDUCTOR ENERGY LABORATORY CO., LTD.
- 当前专利权人: SEMICONDUCTOR ENERGY LABORATORY CO., LTD.
- 当前专利权人地址: JP Atsugi-shi
- 优先权: JP2008-166334 20080625
- 主分类号: H04B10/00
- IPC分类号: H04B10/00
摘要:
A photometric device with a wide dynamic range. The photometric device includes a constant current generation circuit, a fixed clock signal generation circuit which generates a fixed clock signal having a fixed frequency, a photoelectric conversion element, a variable clock signal generation circuit and a digital signal generation circuit. The fixed clock signal generation circuit generates a fixed clock signal that oscillates at a fixed frequency, from constant current The variable clock signal generation circuit generates a variable clock signal that oscillates at a frequency proportional to the amount of photocurrent, from photocurrent generated in the photoelectric conversion element. The digital signal generation circuit sets a measurement period using the fixed clock signal, counts the number of pulses of the variable clock signal that oscillates for the measurement period, and outputs a digital signal including the count value as data.
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