Image display screen
View Patent ↗Image display screen suitable for displaying image frames, at a given screen scanning frequency, comprising, light emitters, circuits for addressing the emitters each comprising, a current modulator able to supply the said emitter with current during the screen display mode, a charge capacitance able to store at each image frame a potential applied to the gate electrode of the current modulator, the potential being representative of a voltage for addressing an image datum during a screen display mode. The screen comprises a control system able to apply a bias voltage to the gate electrode of the current modulator and to the said charge capacitance, during a screen standby mode of a duration greater than the duration of an image frame, the said bias voltage having a bias inverse to the bias of the potential applied to the said charge capacitance during the screen display mode.
1. Image display screen suitable for displaying image frames, comprising:
light emitters distributed as rows of emitters and columns of emitters to form an array of emitters, the emitters of the array being able to be supplied with a current during a screen display mode;
an emitter addressing circuit, associated with each emitter of the array, the said circuit comprising:
a current modulator able to supply current to said emitter, during said display mode, said modulator comprising a gate electrode and two current flow electrodes,
a charge capacitance able to store, at each image frame, an addressing voltage representative of an image datum during said display mode, said voltage being applied to the gate electrode of the current modulator;
a control system able to apply a bias voltage to the gate electrode of the current modulator, during a screen standby mode, said bias voltage having a bias inverse to the bias of the addressing voltage applied to said charge capacitance during the screen display mode,
wherein the control system comprises addressing control means able to apply on the one hand said addressing voltage to the gate electrode of the current modulator during the screen display mode and, on the other hand said bias voltage during the screen standby mode,
the duration of application of said bias voltage having a bias inverse to the bias of the addressing voltage is greater than the duration of an image frame, and
the value of said bias voltage lies between −8 volts and −25 volts.
2. Display screen according to claim 1 , wherein the value of said bias voltage is constant.
3. Display screen according to claim 1 , wherein the control system comprises means of control of scanning of the lines of the screen that are adapted for decreasing the frequency of scanning of the lines of the screen during the screen standby mode to a frequency below the frequency of scanning of the lines during the display mode.
4. Display screen according to claim 1 , wherein the control system comprises means of calculation of the sum of the said voltages applied, at each image frame, to the gate electrode of each current modulator during the screen display mode, the said means of calculation being able to determine characteristics of a bias voltage suitable for being applied to each current modulator, as a function of the said sum of the said voltages applied to this modulator, and in that the control system is able to apply, to each modulator, the said suitable bias voltage determined by the means of calculation, during the screen standby mode.
5. Display screen according to claim 4 , wherein the characteristics of the bias voltage that are determined by the means of calculation comprise the duration of application of the bias voltage.
6. Display screen according to claim 4 , wherein the characteristics of the bias voltage that are determined by the means of calculation comprise the value of the said bias voltage.
7. Display screen according to claim 1 , wherein it comprises means for supplying power to the emitters and in that the control system comprises means for cutting the supply to the emitters during the screen standby mode.
8. Image display screen suitable for displaying image frames, comprising:
light emitters distributed as rows of emitters and columns of emitters to form an array of emitters, the emitters of the array being able to be supplied with a current during a screen display mode;
an emitter addressing circuit, associated with each emitter of the array, the said circuit comprising:
a current modulator able to supply current to said emitter, during said display mode, said modulator comprising a gate electrode and two current flow electrodes,
a charge capacitance able to store, at each image frame, an addressing voltage representative of an image datum during said display mode, said voltage being applied to the gate electrode of the current modulator;
a control system able to apply a bias voltage to the gate electrode of the current modulator, during a screen standby mode, said bias voltage having a bias inverse to the bias of the addressing voltage applied to the said charge capacitance during the screen display mode, wherein
the control system comprises addressing control means able to apply on the one hand said addressing voltage to the gate electrode of the current modulator during the screen display mode and, on the other hand, said bias voltage during the screen standby mode,
the duration of application of said bias voltage having a bias inverse to the bias of the addressing voltage is greater than the duration of an image frame, and
the display screen comprises a power generator for supplying power to the emitters and said control system comprises means arranged between each emitter and said power generator for cutting the supply to the emitters during the screen standby mode.
9. Display screen according to claim 8 , wherein the control system comprises means of control of scanning of the lines of the screen that are adapted for decreasing the frequency of scanning of the lines of the screen during the screen standby mode to a frequency below the frequency of scanning of the lines during the display mode.
10. Display screen according to claim 8 , wherein the control system comprises means of calculation of the sum of the said voltages applied, at each image frame, to the gate electrode of each current modulator during the screen display mode, the said means of calculation being able to determine characteristics of a bias voltage suitable for being applied to each current modulator, as a function of the said sum of the said voltages applied to this modulator, and in that the control system is able to apply, to each modulator, the said suitable bias voltage determined by the means of calculation, during the screen standby mode.
11. Display screen according to claim 10 , wherein the characteristics of the bias voltage that are determined by the means of calculation comprise the duration of application of the bias voltage.
12. Display screen according to claim 10 , wherein the characteristics of the bias voltage that are determined by the means of calculation comprise the value of the said bias voltage.
13. Display screen according to claim 8 , wherein the means for supplying power to the emitters comprise a breaker, arranged between an emitter and said power generator, and a line for controlling the opening and the closing of the breaker.
14. Image display screen suitable for displaying image frames, comprising:
light emitters distributed as rows of emitters and columns of emitters to form an array of emitters, the emitters of the array being able to be supplied with a current during a screen display mode;
an emitter addressing circuit, associated with each emitter of the array, the said circuit comprising:
a current modulator able to supply current to said emitter, during said display mode, said modulator comprising a gate electrode and two current flow electrodes,
a charge capacitance able to store, at each image frame, an addressing voltage representative of image data during said display mode, said voltage being applied to the gate electrode of the current modulator;
a control system able to apply a constant bias voltage to the gate electrode of the current modulator, during a screen standby mode, said bias voltage having a bias inverse to the bias of the addressing voltage applied to said charge capacitance during the screen display mode, wherein
the control system comprises addressing control means able to apply on the one hand said addressing voltage to the gate electrode of the current modulator during the screen display mode and, on the other hand, said bias voltage during the screen standby mode,
the duration of application of said bias voltage having a bias inverse to the bias of the addressing voltage is greater than the duration of an image frame, and wherein
the value of said bias voltage is constant and below −8 volts.
15. Display screen according to claim 14 , wherein the control system comprises means of control of scanning of the lines of the screen that are adapted for decreasing the frequency of scanning of the lines of the screen during the screen standby mode to a frequency below the frequency of scanning of the lines during the display mode.
16. Display screen according to claim 14 , wherein the control system comprises means of calculation of the sum of the said voltages applied, at each image frame, to the gate electrode of each current modulator during the screen display mode, the said means of calculation being able to determine characteristics of a bias voltage suitable for being applied to each current modulator, as a function of the said sum of the said voltages applied to this modulator, and in that the control system is able to apply, to each modulator, the said suitable bias voltage determined by the means of calculation, during the screen standby mode.
17. Display screen according to claim 16 , wherein the characteristics of the bias voltage that are determined by the means of calculation comprise the duration of application of the bias voltage.
18. Display screen according to claim 16 , wherein the characteristics of the bias voltage that are determined by the means of calculation comprise the value of the said bias voltage.
19. Display screen according to claim 14 , wherein it comprises means for supplying power to the emitters and in that the control system comprises means for cutting the supply to the emitters during the screen standby mode.