摘要:
The present invention is to provide a fluorescent lamp dimming apparatus capable of continuously dimming the fluorescent lamp, and capable of eliminating a fluctuation of light outputs, and in particular, capable of turning ON the fluorescent lamp in a low temperature. The fluorescent lamp dimming apparatus is comprised of a lamp voltage detecting circuit for detecting a discharge voltage of the fluorescent lamp, and a control unit intermittently controls the output frequency of a high frequency power supply in such a manner that the output frequency becomes higher than a dimming frequency based on the dimming signal so as to periodically change a current supplied to the fluorescent lamp into a low current; and when the output frequency of the high frequency power supply becomes higher than the dimming frequency, the control unit sets a lower limit dimming set value based upon a detection voltage of the lamp voltage detecting circuit in order that the output frequency of the high frequency power supply is controlled to become lower than, or equal to the upper limit frequency in accordance with the lower limit dimming set value.
摘要:
A current flowing through a discharge lamp 4 is detected by a current detecting circuit 5, and the detected current is outputted as a lamp current signal A to a feedback control circuit 7 where a difference between the lamp current signal A and the dimming control signal B is obtained and amplified, and then a amplified signal D is outputted to an adder 12 which adds the amplified signal D to the dimming control signal B to constitute a control signal E. The control signal is fed back to a high frequency power supply 2. When a comparing circuit 15 detects that the light level of the dimming control signal B with respect to the full light becomes higher than or equal to 40% to 60%, the feedback circuit is disconnected by operating a switch 13 provided between an error amplifying circuit 9 and an adder 12 to stop the feedback control. When a light level of a discharge lamp 104 is smaller than or equal to a predetermined value, first and second reference voltage 108a and 108b are switched by a two-stage switching circuit 109. A comparator 107 compares a detection voltage 106 of the discharge lamp 104 with the first reference voltage 108a, or the detection voltage 106 with the second reference voltage 108b. When the voltage of the discharge lamp 104 becomes high, a control circuit 110 supplies to a high frequency power supply 102, a control signal 112 for interrupting, or reducing an output of the high frequency power supply 102.
摘要:
A current flowing through a discharge lamp 4 is detected by a current detecting circuit 5, and the detected current is outputted as a lamp current signal A to a feedback control circuit 7 where a difference between the lamp current signal A and the dimming control signal B is obtained and amplified, and then a simplified signal D is outputted to an adder 12 which adds the amplified signal D to the dimming control signal B to constitute a control signal E. The control signal is fed back to a high frequency power supply 2. When a comparing circuit 15 detects that the light level of the dimming control signal B with respect to the full light becomes higher than or equal to 40% to 60%, the feedback circuit is disconnected by operating a switch 13 provided between an error amplifying circuit 9 and an adder 12 to stop the feedback control.
摘要:
After a DC voltage outputted from a rectifying circuit 2 is smoothed by a smoothing capacitor 3, transistors 4 and 5 are turned ON/OFF so as to convert the smoothed DC voltage into high frequency power. This high frequency power is supplied via a second resonant circuit 22 to a load circuit 23 and a first resonant circuit 17, and a high frequency voltage is superimposed on the output of the rectifying circuit 2 from the first resonant circuit 17.
摘要:
When an inverter circuit is driven at a predetermined driving frequency, an amount of current change per predetermined period of time of an input current or a coil current is detected, and a heating period from a start of control until the amount of current change becomes a set value or less is measured. Then, the inverter circuit is controlled to reduce high frequency power to be supplied to a heating coil in accordance with a length of the measured heating period.
摘要:
When an inverter circuit is driven with a predetermined driving frequency, an amount of current change of an input current or a coil current in a set period is detected, and high frequency power to be supplied from the inverter circuit to a heating coil is adjusted in accordance with the amount of current change.
摘要:
When an inverter circuit is driven with a predetermined driving frequency, an amount of current change of an input current or a coil current in a set period is detected, and high frequency power to be supplied from the inverter circuit to a heating coil is adjusted in accordance with the amount of current change.
摘要:
In the wafer chamfering method, there is used a disk-shaped grindstone 8 which includes: a peripheral edge portion serving as a grinding surface 1; a flat portion formed in the central portion of the grinding surface 1 in the width direction thereof; and, two edge portions 5 respectively formed on the two sides of the flat portion 2 in the width direction thereof and made in the form of the shape of the valley portion of the notch portion 4 of a disk-shaped wafer 3 to be chamfered. In operation, in the wafer chamfering method, while rotating the above grindstone 8, the grindstone 8 is revolved in the thickness direction of the wafer 3 to thereby chamfer the wafer 3. Especially, the present wafer chamfering method comprises two steps: that is, a circumferential portion grinding step in which the grindstone is supported such that it stands upright or at right angles to the circumferential portion 6 of the wafer 3 at their respective mutual contact points and only the flat portion of the grindstone 8 is contacted with the mutual contact points to thereby chamfer the peripheral edge portion of the wafer 3; and, a notch portion grinding step in which the grindstone is supported such that it is inclined with respect to the diameter direction of the notch portion of the wafer 3 by an angle of about 45° in the circumferential direction of the wafer 3 and the edge portions 5 or both of the edge portions 5 and flat portion 2 are used to chamfer the notch portion 4 of the wafer 3.
摘要:
A spindle 23 of a grinding wheel 28 is rotatively borne by a bench 22 for the grinding wheel through hydrostatic thrust bearings 26 and 27. A pressure regulator 38 for regulating the pressure which must be supplied to at least either of supply ports 26a and 27a opposite to each other in the direction of the axial line of the spindle 23 in the hydrostatic thrust bearings 26 and 27 is provided. The pressure regulator 38 has a changing member for changing a passage for choking the fluid and the length of the choking passage.
摘要:
A spindle 23 of a grinding wheel 28 is rotatively borne by a bench 22 for the grinding wheel through hydrostatic thrust bearings 26 and 27. A pressure regulator 38 for regulating the pressure which must be supplied to at least either of supply ports 26a and 27a opposite to each other in the direction of the axial line of the spindle 23 in the hydrostatic thrust bearings 26 and 27 is provided. The pressure regulator 38 has a changing member for changing a passage for choking the fluid and the length of the choking passage.