公开(公告)号：JP2002351417A

公开(公告)日：2002-12-06

申请号：JP2001156177

申请日：2001-05-24

Applicant: IBM

Inventor： SAKURAI TAKAAKI ,  WATANABE YOSHIAKI ,  YANA TOSHIYUKI ,  KARUBE SATOSHI

IPC: G02F1/133 ,  G09G3/20 ,  G09G3/36 ,  H02M3/155

Abstract: PROBLEM TO BE SOLVED: To provide a liquid crystal driving power supply circuit in which a driving power supply voltage to be supplied to a driver circuit is precisely generated by employing a low precision reference voltage generating circuit. SOLUTION: A driving power supply circuit 11 consists of a DC/DC converter 34 which generates a voltage having a size based on oscillating signals VOUT from a power supply voltage Vcc of the circuit 11 and outputs the generated voltage as a driving power supply voltage Vdcdc , a stable power supply circuit 60 which generates a most significant reference potential Vref H used to generate a gradation voltage in a driver circuit, a comparison section 46 which computes the difference between the voltage Vdcdc and the potential Vref H and outputs the computed difference as a difference voltage, an internal reference voltage generating section 42 which generates an internal reference voltage VREF having a prescribed size, an error amplifying section 44 which computes the difference between a reference voltage that is determined by the generated voltage VREF and the difference voltage and a PWM converting section 32 which outputs the signals VOUT in accordance with the difference.

公开(公告)号：JPH08115793A

公开(公告)日：1996-05-07

申请号：JP24905194

申请日：1994-10-14

Applicant: HITACHI LTD ,  IBM

Inventor： IKEDA RYUICHI ,  MATSUMOTO SHUZO ,  SUGINO MOTOHIRO ,  KAWABATA KENJI ,  OKADA TAKASHI ,  WATANABE YOSHIAKI

IPC: H05B41/24 ,  H05B41/285

Abstract: PURPOSE: To provide a lighting device for a discharge lamp, which detects an abnormal state of a discharge tube and also the lighting device of discharge lamp and protects the discharge lamp and the lighting device of the discharge lamp by multiplying the measured results of electric current and electric voltage, and halting or decreasing the output of a inverter when the multiplied result is equal to a prescribed value determined in advance. CONSTITUTION: An inverter 2 converts an output of a direct current power source 1 to a high-frequency output and feed it to a discharge tube 3. Thereby the discharge tube 3 is turned on by a high frequency and at this time necessary electric power for lighting is supplied by the power source 1. During the period when the discharge tube 3 is on at a normal condition, a voltage and a current of a high frequency which are supplied to the discharge lamp 3 are constant and therefore its power consumption is easily determined. A value of electric power is indicated by a value obtained by multiplying means 7 through the measured results by voltage measuring means 3 and current measuring means 6. The control circuit 4 halts the operation of the inverter 2 and turn off the discharge lamp 3 at a time when the output of means 7 is equal to a prescribed value.

公开(公告)号：JP2002244621A

公开(公告)日：2002-08-30

申请号：JP2001030240

申请日：2001-02-06

Applicant: IBM

Inventor： WATANABE YOSHIAKI ,  SAKURAI TAKAAKI ,  KIKUCHI YASUTO

IPC: G02F1/133 ,  G09G3/20 ,  G09G3/36

Abstract: PROBLEM TO BE SOLVED: To provide a liquid crystal display device capable of reducing flickers irrespective of any display pattern. SOLUTION: In a 1st frame, driving voltages with polarities defined according to random numbers in the unit of rows are applied, and in the following 2nd frame, the driving voltages of the inverted polarities of those in the 1st frame are applied. The polarity patterns are alternately repeated.

公开(公告)号：JPH11153796A

公开(公告)日：1999-06-08

申请号：JP5379098

申请日：1998-03-05

Applicant: IBM ,  STANLEY ELECTRIC CO LTD

Inventor： SUZUKI MASARU ,  WATANABE YOSHIAKI ,  OKI YOJI ,  KAWADA KOJI

IPC: G09F9/00 ,  F21V8/00 ,  G02B5/30 ,  G02B6/00 ,  G02B6/10 ,  G02F1/1335 ,  G02F1/13357

Abstract: PROBLEM TO BE SOLVED: To prevent the reabsorption of exit light and to prevent the generation of dark and bright stripe patterns by further laminating plural light transmission body films on the front surface on the large area side of a light transmission body unit body. SOLUTION: The light transmission body unit consists of the light transmission body unit body and further the plural light transmission body films laminated thereon and includes the unit body, of which one flank is a light incident surface, a reflection plate which is arranged on the other flank of the unit body and a means which is arranged between the unit body and the reflection plate and changes the polarization direction of the light. The other flank of the light transmission body inclines with a thickness direction. The plural light transmission body films are laminated on the front surface on the large area side of the light transmission body unit body. In such a case, the thickness of the light transmission body films is reduced in order to eliminate the dark and bright stripe patterns. The body part of the light transmission body, i.e., the right diagonal lower half of Fig., is required to be shaped as it is in order for the direct incidence of the light of a CFL from the end face and the remaining half (left diagonal above) is not required to be of the same thickness.

公开(公告)号：JPH09102399A

公开(公告)日：1997-04-15

申请号：JP25848795

申请日：1995-10-05

Applicant: HITACHI LTD ,  IBM

Inventor： OKADA TAKASHI ,  KAWABATA KENJI ,  IKEDA RYUICHI ,  SUGINO MOTOHIRO ,  WATANABE YOSHIAKI

IPC: H05B41/282 ,  H05B41/392 ,  H05B41/29

Abstract: PROBLEM TO BE SOLVED: To provide good circuit efficiency and a wide dimming range in a dimming discharge lamp-lighting apparatus. SOLUTION: This lighting apparatus is a current feedback discharge lamp- lighting apparatus composed of a chopper circuit 2 and a discharge lamp-lighting circuit 3 containing a DC/AC converter part. Lighting is dimmed by a dimming system to control a lamp current from 40% to 100% by a dimming signal switching apparatus 11 and lighting is dimmed by repeating lighting and extinguishing operations of a discharge lamp 5 by a chopping dimming signals from 5% to 40%. Consequently, without lowering the circuit efficiency so much, the dimming can be carried out to 5%.

公开(公告)号：JPH09129382A

公开(公告)日：1997-05-16

申请号：JP26883495

申请日：1995-10-17

Applicant: IBM

Inventor： WATANABE YOSHIAKI ,  YAMAGUCHI AKIYA ,  SUZUKI MASARU

IPC: G02B6/00 ,  G02F1/133 ,  H05B41/24 ,  H05B41/285

Abstract: PROBLEM TO BE SOLVED: To cope with delay in lighting up caused by high pressure cable failure or darkness effect by comparing current values of current detection means of a transformer secondary winding and current detection means of electric discharge tube with each other, and shutting out a power supply when a difference of specified value or more is detected. SOLUTION: A current detected current detection part 31 is installed on the side of secondary winding 21b of a transformer is called I-tr while a detected current of tube current detection part 25 detecting a current flowing in an electric discharge tube 15 is called I-lamp. When the currents I-tr and I-lamp are input to a comparator 33 and it is found that the difference therebetween is over a specified value, it is determined abnormal and a shut out signal is output to a power supply. With the provision of current detection means on the secondary side of transformer, the purpose is attained.

公开(公告)号：JP2001337730A

公开(公告)日：2001-12-07

申请号：JP2000146376

申请日：2000-05-18

Applicant: IBM

Inventor： SAKURAI TAKAAKI ,  WATANABE YOSHIAKI ,  YOSHIKAWA HIROSHI

IPC: G09G3/36 ,  G05F1/56 ,  G05F3/22 ,  G09G3/20

Abstract: PROBLEM TO BE SOLVED: To provide a power supply circuit which reduces total power consumption for the circuit. SOLUTION: R1-Rm-1 are internal resistance of a TFT driver. Q1-Qm are active elements such as transistors or the like, and control Vout (1) voltage, Vout (2) voltage ... Vout (m) voltage by changing their conductance. Output voltage Vout (1) - Vout (m) are compared with voltage V1-Vm given from a voltage regulating circuit by differential amplifiers U1-Um which have functions of feedback circuit and calculating circuit, and are controlled to be same voltage as the reference voltage by each transistor. The total power consumption for the circuit can be reduced because the active elements are inserted between plural output nodes of which required voltage balance are predetermined, and by controlling the conductance of the elements, the required reference voltage is supplied to each node.

公开(公告)号：JPH10228991A

公开(公告)日：1998-08-25

申请号：JP2869197

申请日：1997-02-13

Applicant: HITACHI LTD ,  IBM

Inventor： SUGINO MOTOHIRO ,  IKEDA RYUICHI ,  KAWABATA KENJI ,  WATANABE YOSHIAKI

IPC: H05B41/282 ,  H05B41/392 ,  H05B41/29

Abstract: PROBLEM TO BE SOLVED: To have sufficient flexibility without limiting a value and content to be set by using a computing means, in which a set value is input from an external memory so as to store it in a set value memory. SOLUTION: A serial data communication control circuit 23 outputs the serial clock output signal 27 at the time of initial setting after a power source is closed, and reads out a tube current target value housed in a data memory 41 so as to store it in a target value register inside of a RAM 21. Thereafter, a CPU 19 compares the tube current detection value, which is stored in the detection value register, with the tube current target value. In the case where the tube current detection value is larger than the tube current target value, processing for reducing the duty ratio of the pulse output from a PWM pulse control means 24 is performed. In the case where the tube current detection value is smaller than the tube current target value, processing for increasing the duty ration of the pulse to be output from the control means 24 is performed. As a result, tube current flowing to a discharge lamp 12 at a value corresponding to the target value is obtained.

公开(公告)号：JPH09103068A

公开(公告)日：1997-04-15

申请号：JP25837995

申请日：1995-10-05

Applicant: HITACHI LTD ,  IBM

Inventor： SUGINO MOTOHIRO ,  MATSUMOTO SHUZO ,  IKEDA RYUICHI ,  KAWABATA KENJI ,  OKADA TAKASHI ,  WATANABE YOSHIAKI

IPC: H05B41/282 ,  G05F1/10 ,  G05F1/40 ,  G05F1/56 ,  H02M3/155 ,  H05B41/29

Abstract: PROBLEM TO BE SOLVED: To control the output voltage stably even if the input voltage fluctuates over a control speed by selecting between an output control based on the increment/decrement of a detected output value and an output control based on the absolute value of input voltage. SOLUTION: The power supply comprises first means for controlling the output based on the increment/decrement of a value received from an output detecting means, and second means for controlling the output such that the value from output detecting means is equal to a reference value. When the input voltage is stable, feedback control is performed through increment/ decrement tuns production a stabilized output. When the input voltage fluctuates abruptly, direct control is performed depending on the input voltage thus preventing significant deviation of the output voltage from a specified value. Since feedback control can be restarted upon ending fluctuation of input voltage, settling time of output voltage can be shortened.