Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J1/00—Photometry, e.g. photographic exposure meter
  • G01J1/42—Photometry, e.g. photographic exposure meter using electric radiation detectors
  • G01J1/44—Electric circuits
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J1/00—Photometry, e.g. photographic exposure meter
  • G01J1/42—Photometry, e.g. photographic exposure meter using electric radiation detectors
  • G01J1/44—Electric circuits
  • G01J2001/4446—Type of detector
  • G01J2001/446—Photodiode

Definitions

• This invention relates to an electric coupling in an instrument for detecting ultra-violet radiation, visible light or infrared radiation, comprising a photo-diode of silicon or germanium, a precision resistor for measuring, via which generated photo-electric current generates a voltage, and a voltmeter with low leakage current for measuring the voltage generated.
• the present invention has the object to render possible a structural design, which is less expensive, simpler and safer than the ones known and commercially available.
• the invention is characterized in that the precision resistor and calibrated voltmeter each are connected in parallel over the photo-diode.
• Fig. 1 shows schematically a circuit diagram for a known photometric coupling
• Fig. 2 shows the current-voltage characteristic of the photo-diode in the forward direction
• Fig. 5 shows a circuit diagram according to the invention idea.
• the coupling shown in Fig. 1 thus, comprises a photo-diode F and a voltmeter connected in parallel therewith. Before the voltmeter an operation amplifier 0 and a resistance R A are connected. The resistance can be exchanged against resistances of a different size for changing the measurement ranges.
• the coupling acts in such a way, that the photo-diode F at exposure to the radiation E generates in its backward direction a photo-electric current I F .
• the photoelectric current I F is passed on via the amplification resistor R A of the operation amplifier 0.
• Generated voltage is shown by the voltmeter V.
• Fig. 2 the current-voltage characteristic of the photo-diode is shown in forward direction, i.e. opposed to the direction of the photo-electric current generation. It appears from this that at low voltage V in the forward direction the diode acts as an insulator. The resistance is very high, near the origin of coordinates. This applies especially to silicon diodes.
• Fig. 3 shows the coupling according to the invention idea. It appears from it that the voltmeter and the measurement resistor R A both are connected in parallel over the diode F The measurement resistances can be exchanged automatically for changing the measurement ranges.
• the resistor R L illustrates the resistance in the barrier layer of the photo-diode in the conducting direction, i.e. in Fig. 2.
• I F is the photo-electric current in the backward direction of the diode generated by the radiation E.
• the leakage current is in the forward direction.
• I V is the very low leakage current over the modern voltmeter V.
• the magnitude for the leakage current is one pico-ampere.
• the voltmeter is adjusted so that maximum deflection is attained at a voltage equal to or lower than ⁇ V.
• Calibration with a known radiation E can be carried out directly by adjustment of the voltmeter when R A was chosen so that I F ⁇ R A is lower than ⁇ V.
• the coupling according to the invention idea implies substantial savings in material and labour costs and a superior simplicity of handling owing to the automatic zero-point stability.
• the voltmeter certainly may contain active amplification, but due to high-technology mass production modern voltmeters are zero-point stable in very varying temperatures.
• Modern voltmeters - generally digital ones also are well capable to resolve voltages as small as have been reported here (for example 50 mV in two-thousand scale divisions).

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Photometry And Measurement Of Optical Pulse Characteristics (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20360834

Family Applications (1)

Country Status (6)

Families Citing this family (4)

Citations (2)

Family Cites Families (6)

• 1985
  • 1985-07-05 SE SE8503358A patent/SE447934B/sv not_active IP Right Cessation
• 1986
  • 1986-07-04 JP JP61503937A patent/JPS63500269A/ja active Pending
  • 1986-07-04 DE DE19863690352 patent/DE3690352T/de active Pending
  • 1986-07-04 US US07/034,153 patent/US4793704A/en not_active Expired - Lifetime
  • 1986-07-04 GB GB8704452A patent/GB2191283B/en not_active Expired
  • 1986-07-04 WO PCT/SE1986/000325 patent/WO1987000271A1/en active Application Filing
  • 1986-07-04 DE DE3690352A patent/DE3690352C2/de not_active Expired - Fee Related

Patent Citations (2)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events