Display and display driver with on/off power controller used to prevent damage to the display

Abstract

Signal management control units 47 1 -47 n of respective scan drivers LSI in an LCD module are cascade-connected and each have the same construction. A detected signal of the signal management control unit 47J is a data signal latch clock LP applied to a terminal CKB 1 . A detected signal of the signal management control unit 47 2 is a frame start signal SP applied to a terminal CKB 2 . A detected signal of the signal management control unit 47n is an AC-transforming clock FR applied to a terminal CKBn. The signal management control unit 47 1 includes a signal stop detection circuit 48 serving as a signal detection means for detecting a stop of the detected signal delay circuit 49 processing circuit 51 consisting of a signal delay circuit 49 and a logic circuit 50. When stopping oscillations of, e.g., the frame start signal SP, outputs T 1 -T n of the circuit 51 change to an L level. Hence, a display-off signal DF of the LCD module assumes the L level. A liquid crystal panel is forcibly set in a display-off mode. As a result, even if the frame start signal SP is stopped due to some cause, a liquid crystal application voltage is set down to zero. It is, therefore, possible to avoid a liquid crystal DC drive and prevent a deterioration of the liquid crystal.

1. A method of controlling a flat display unit comprising a flat display panel driven in accordance with display driving voltages, display driver means for selecting the display driving voltages supplied to the flat display panel and a display power source circuit for supplying the display driving voltages to the display driver means in response to a power control signal, the method of controlling the flat display unit comprising the steps of:
 detecting a logic power voltage activating a logic circuit of the flat display unit by the display driver means;    supplying the power control signal from the display driver means to the power source circuit, said power control signal having a delay time after the detection of said logic power voltage;    supplying the display driving voltages to the display driver means in response to the power control signal by the power source circuit; and    selecting the display driving voltages supplied from the power source circuit to the flat display panel by the display driver means.    
     
     
       2. The method according to  claim 1 , further comprising the step of supplying a start signal controlling a start of display to the display driver means after supplying the display driving voltages to the display driver means. 
     
     
       3. A method of controlling a flat display device comprising a flat display panel module unit and a display control unit for supplying control signals to control display of the flat display panel module unit, said flat display panel module unit including a flat display panel driven in accordance with display driving voltages, display driver means for selecting the display driving voltages to the flat display panel and a display power source circuit for supplying the display driving voltages to the display driver means in response to a power control signal, the method of controlling the flat display unit comprising the steps of:
 supplying the power control signal to the power source circuit by the display driver means, the power control signal having a delay time after a logic power voltage has been supplied to a logic circuit of the flat display device;    supplying the display driving voltages to the display driver means in response to the power control signal by the power source circuit;    supplying a display start signal controlling a start of the selection of the display driving voltages by the display driver means in response to the control signal supplied from the display control unit, said display start signal having a delay tine after the power control signal has supplied to the power source circuit; and    selecting the display driving voltages supplied from the power source circuit to supply to the flat display panel in response to the display start signal.    
     
     
       4. The method according to  claim 3 , wherein the flat display panel module unit is arranged separately from the display control unit. 
     
     
       5. A flat display unit comprising:
 a flat display panel for being driven in accordance with display driving voltages;    display driver means for selecting the display driving voltages supplied to said flat display panel, said display driver means comprising a logic circuit and a detection means for detecting a logic power voltage, activating said logic circuit and for supplying a power control signal having a delay time after the detection of the logic power voltage; and    a display power source circuit for supplying the display driving voltages to said display driver means in response to the power control signal.    
     
     
       6. A flat display device comprising a flat display panel module unit and a display control unit for supplying control signals to control display of the flat display panel module unit, said flat display panel module unit comprising:
 a flat display panel driven in accordance with display driving voltages;    display driver means for selecting the display driving voltages supplied to said flat display panel and for supplying a power control signal having a delay time after a logic power voltage has been supplied to a logic circuit of said display driver means; and    a display power source circuit for supplying the display driving voltages to said display driving means in response to the power control signal,    wherein said display driver means starts the selection of the display driving voltages in response to a display start signal having a delay time after the power control signal has supplied to said power source circuit.    
     
     
       7. A display apparatus having a display body module unit and a separately disposed display control unit, the display body module unit including a display panel and a display driving means for driving the display panel, the display apparatus comprising:
   a signal management control means comprising a signal detection means for detecting errors in control signals output from the display control unit, and a sequence processing means for changing the shape of a signal on the display body module unit based on a detection signal from the signal detection means;      the signal detection means comprising a signal - stop detection means for detecting stoppage of a control signal; and        the sequence processing means comprising a forced - stop control means for unconditionally control - setting a display panel voltage to be applied to the display panel by the display driving means to substantially zero in response to a detection output of the signal - stop detection means;      the forced - stop control means comprising a first signal delay means for controlling setting the display panel voltage to be applied to the display panel after a first delay time following a non - detection output of the signal - stop detection means; and            a power source control means for controlling the on/off state of a display panel power source means in order to generate a display panel drive voltage based on an output from the signal - stop detection means and a power on/off signal of a logic - side supply voltage.     
     
     
       8. A display apparatus as described in  claim 7 , wherein the power source control means comprises a second signal delay means for controlling turning the display panel power source means on after a second delay time, which is shorter than the first delay time, following the non- detection output of the signal - stop detection means.   
     
     
       9. A display apparatus as described in  claim 7 , wherein the forced- stop control means comprises a forced - blanking display signal control terminal for controlling transmission of output from the forced - stop control means.   
     
     
       10. A display apparatus as described in  claim 9 , wherein there are n signal management control means where n is a positive integer, and
   a different type of detected signal is input as a control signal to each of the signal management control means.     
     
     
       11. A display apparatus as described in  claim 10 , wherein k= 1  to n− 1 , and a control output of the k- th signal management control means is applied as the forced - blanking display signal of the  ( k+ 1   )- th signal management control means, and the on/off display state of the display driving means is controlled based on control output of an n - th signal management control means.   
     
     
       12. A display apparatus as described in  claim 11 , wherein the first signal delay means is an N- stage D - type flip - flop, where N is a positive integer, to which a frame start signal is input and which is settable/resettable based on output from the signal - stop detection means; and      the second signal delay means in an M - stage D - type flip - flop, where M is a positive integer less than N, to which a frame start signal is input and which is settable/resettable based on output from the signal - stop detection means.     
     
     
       13. A display apparatus as described in  claim 7 , wherein the display panel is a liquid crystal display panel. 
     
     
       14. A display apparatus as described in any of  claim 7 , wherein the display panel is a plasma display panel. 
     
     
       15. A display panel drive apparatus disposed on a display body module unit for supplying a display drive voltage to a display panel based on signals from a display control unit, comprising:
   a signal management control means comprising a signal detection means for detecting errors in control signals output from the display control unit, and a sequence processing means for changing the shape of a signal on the display body module unit based on a detection signal of the signal detection means;     the signal detection means comprising a signal - stop detection means for detecting stoppage of a control signal; and        the sequence processing means comprising a forced - stop control means for unconditionally control - setting a display panel voltage to be applied to the display panel to substantially zero based on output of a signal - stop - detected signal by the signal - stop detection means;      the forced - stop control means comprising a first signal delay means for controlling setting the display panel voltage to be applied to the display panel after a first delay time following a non - detection output of the signal - stop detection means; and            the signal management control means comprising a power source control means for controlling the on/off state of a display panel power source means in order to generate a display panel drive voltage based on an output from the signal - stop detection means and a power on/off signal of a logic - side supply voltage.     
     
     
       16. A display panel drive apparatus as described in  claim 15 , wherein the power source control means comprises a second signal delay means for controlling turning the display panel power source means on after a second delay time, which is shorter than the first delay time, following the non- detection output of the signal - stoppage detection means.   
     
     
       17. A display panel drive apparatus as described in  claim 16 , wherein the forced- stop control means comprises a forced - blanking display signal input terminal for controlling transmission of an output from the forced - stop control means.   
     
     
       18. A display panel drive apparatus as described in  claim 17 , wherein the first signal delay means is an N- stage D - type flip - flop, where N is a positive integer, to which a frame start signal is input and which is settable/resettable based on an output from the signal - stop detection means; and      the second signal delay means is an M - stage D - type flip - flop, where M is a positive integer less than N, to which the frame start signal is input and which is settable/resettable based on an output from the signal - stop detection means.     
     
     
       19. A display panel drive apparatus as described  claim 15 , wherein the display panel drive apparatus is a liquid crystal drive device for driving a liquid crystal display panel. 
     
     
       20. A display panel drive apparatus as described in  claim 19 , wherein the liquid crystal drive device is a semiconductor integrated circuit. 
     
     
       21. A display panel drive apparatus as described in  claim 20 , wherein the semiconductor integrated circuit is a Y driver. 
     
     
       22. A display panel drive apparatus as described in  claim 21 , wherein the Y driver is a scanning driver of a passive matrix LCD. 
     
     
       23. A display panel drive apparatus as described in  claim 21 , wherein the Y driver is a gate driver of an active matrix LCD. 
     
     
       24. A display control apparatus for controlling a display panel containing display elements, comprising:
   a logic circuit unit to which a logic power source  ( Vcc )  is supplied;        a power - on detection circuit comprising a time constant circuit having one side connected to the logic power source  ( Vcc )  and another side connected to a ground line GND, and a potential detection circuit  ( INV 2   )  that receives an output of the time constant circuit after the logic power source is applied and that outputs a reset signal to a detection output line until a specific potential is exceeded;        a signal delay control unit connected to the detection output line, that receives as an input the reset signal supplied to the detection output line, and that outputs a control signal delayed by a specific delay time;        a scan driver circuit that receives the output of the signal delay control unit and a forced - blanking display signal  ( /DFF ) , and that outputs a display blanking signal  ( /DF )  and display power control signal  ( /POFF )  instructing a display power source circuit to start producing a power supply output based on the combination of the signal delay control unit output and the forced - blanking display signal  ( /DFF ) ; and        a display driving circuit that is connected to the output of the scan driving circuit and that selects a specific supply source from the display power source circuit according to an ACTIVE/INACTIVE state of the display blanking signal  ( /DF );      wherein the display panel is controlled to be blank at least until the signal delay control unit output goes ACTIVE after the logic power source is applied.