Source: http://www.google.com/patents/US7466302?ie=ISO-8859-1&dq=5,666,293
Timestamp: 2014-03-09 17:52:21
Document Index: 156348838

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Patent US7466302 - Display apparatus and method of driving the same - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsA light generating part generates a first light based on a first control signal. A first driving part outputs a panel driving signal. A display panel receives the first light or a second light that is provided from an exterior to display an image based on the panel driving signal. A sensing part outputs...http://www.google.com/patents/US7466302?utm_source=gb-gplus-sharePatent US7466302 - Display apparatus and method of driving the sameAdvanced Patent SearchPublication numberUS7466302 B2Publication typeGrantApplication numberUS 10/949,068Publication dateDec 16, 2008Filing dateSep 24, 2004Priority dateDec 19, 2003Fee statusPaidAlso published asCN1629914A, CN100470625C, US20050134548Publication number10949068, 949068, US 7466302 B2, US 7466302B2, US-B2-7466302, US7466302 B2, US7466302B2InventorsJin-hong Kim, Cheol-woo Park, Chong-Chul Chai, Kyoung-Ju ShinOriginal AssigneeSamsung Electronics Co., Ltd.Export CitationBiBTeX, EndNote, RefManPatent Citations (5), Referenced by (2), Classifications (20), Legal Events (3) External Links: USPTO, USPTO Assignment, EspacenetDisplay apparatus and method of driving the sameUS 7466302 B2Abstract A light generating part generates a first light based on a first control signal. A first driving part outputs a panel driving signal. A display panel receives the first light or a second light that is provided from an exterior to display an image based on the panel driving signal. A sensing part outputs a sensing signal based on the second light. A second driving part compares a reference voltage range with the sensing signal to output the first control signal. The reference voltage range is determined by a first reference voltage and a second reference voltage. Therefore, the light generating part is turned on/off based on the second light to decrease the power consumption of the light generating part, and an operation of the light generating part is stabilized.
a light generating part generating a first light based on a first control signal;
a first driving part outputting a panel driving signal;
a display panel disposed on the light generating part to receive the first light that is generated from the light generating part and to receive a second light that is provided from an exterior to display an image based on the panel driving signal;
a sensing part disposed on the display panel to output a sensing signal based on the second light to the display panel; and
a second driving part disposed between the sensing part and the light generating part to compare a reference voltage range with the sensing signal to output the first control signal to cause the light generating part to generate light, the reference voltage range being determined based on a first reference voltage and a second reference voltage higher than the first reference voltage,
the first control signal being in substantially same state or opposite state with respect to a second control signal corresponding to an on/off state of the light generating part.
2. The display apparatus of claim 1, wherein the second driving part comprises:
a first comparator comparing the sensing signal with the first reference level to output a first state signal;
a second comparator comparing the sensing signal with the second reference level to output a second state signal; and
a switching part applying the first control signal to the light generating part based on the first and second state signals.
3. The display apparatus of claim 2, wherein the second driving part stores the second control signal corresponding to the on/off state of the light generating part, and further comprises a memory part storing the first control signal outputted from the switching part that receives the second control signal.
4. The display apparatus of claim 2, wherein the first state signal is in a low state in case that the sensing signal is higher than the first reference level, the first state signal is in a high state in case that the sensing signal is lower than the first reference level, the second state signal is in the low state in case that the sensing signal is higher than the second reference level, and the second state signal is in the high state in case that the sensing signal is lower than the second reference level.
5. The display apparatus of claim 4, wherein the switching part outputs the first control signal that is substantially same as the second control signal, when the light generating part is turned off and the first and second state signals are in the low state.
6. The display apparatus of claim 4, wherein the switching part outputs the first control signal that is opposite to the second control signal, when the light generating part is turned off and the first and second state signals are in the high state.
7. The display apparatus of claim 4, wherein the switching part outputs the first control signal that is substantially same as the second control signal, when the light generating part is turned off and the first and second state signals are in the low state and the high state, respectively.
8. The display apparatus of claim 4, wherein the switching part outputs the first control signal that is opposite to the second control signal, when the light generating part is turned on and the first and second state signals are in the low state.
9. The display apparatus of claim 4, wherein the switching part outputs the first control signal that is substantially same as the second control signal, when the light generating part is turned on and the first and second state signals are in the high state.
10. The display apparatus of claim 4, wherein the switching part outputs the first control signal that is substantially same as the second control signal, when the light generating part is turned on and the first and second state signals are in the low state and the high state, respectively.
11. The display apparatus of claim 1, wherein the display panel comprises a display area and a peripheral area that is disposed at a position adjacent to the display area, and a plurality of gate lines, a plurality of data lines and the sensing part are disposed in the display area to display an image.
12. The display apparatus of claim 11, wherein a center of the display area corresponds a center of the display panel.
13. The display apparatus of claim 11, wherein a pixel transistor is disposed in the display area, and the pixel transistor comprises a first gate electrode electrically connected to one of the gate lines, a first source electrode electrically connected to one of the data lines and a first drain electrode electrically connected to a pixel electrode.
14. The display apparatus of claim 11, wherein the sensing part comprises a sensing transistor outputting the sensing signal based on the second light, and a first storage capacitor receiving a first voltage based on the sensing signal.
15. The display apparatus of claim 14, wherein the sensing transistor comprises amorphous silicon.
16. The display apparatus of claim 14, wherein the first driving part comprises a plurality of stages electrically connected to one another and a gate driving integrated circuit outputting gate signals to the gate lines based on a first driving voltage, a second driving voltage and a start signal.
17. The display apparatus of claim 16, wherein the sensing transistor comprises a second drain electrode receiving the first driving voltage, a second gate electrode receiving the second driving voltage and a second source electrode outputting the sensing signal, and the first storage capacitor comprises a first electrode receiving the second driving voltage and a second electrode receiving the sensing signal.
18. The display apparatus of claim 16, further comprising a read-out part that reads the first voltage charged in the first storage capacitor.
19. The display apparatus of claim 18, wherein the read-out part further comprises: a read-out transistor outputting a second voltage based on the first voltage and an output signal of a last stage of the stages; and a second storage capacitor that receives the second voltage outputted from the switching transistor.
20. The display apparatus of claim 19, wherein the read-out transistor comprises a third drain electrode receiving the first voltage, a third gate electrode receiving the output signal of the last stage of the stages and a third source electrode outputting the second voltage, and the second storage capacitor comprises a third electrode receiving the second driving voltage and a fourth electrode receiving the second voltage.
21. The display apparatus of claim 16, wherein the gate driving integrated circuit is disposed in the peripheral area.
22. The display apparatus of claim 21, wherein the gate driving integrated circuit comprises amorphous silicon.
23. The display apparatus of claim 16, wherein the first driving part comprises one chip having the gate driving integrated circuit and a data diving integrated circuit outputting data signals to the data lines.
24. The display apparatus of claim 16, further comprising a reset part that initializes the sensing part at every predetermined interval.
25. The display apparatus of claim 24, wherein the reset part comprises a fourth gate electrode receiving the start signal, a fourth drain electrode receiving the first voltage and a fourth source electrode receiving the second driving voltage.
26. A method of driving a display apparatus comprising:
generating a first light based on a control signal;
outputting a panel driving signal;
receiving the first light and a second light that is provided from an exterior to display an image based on the panel driving signal;
outputting a sensing signal based on the second light; and
comparing in a first comparator the sensing signal with a first reference level and producing a first state signal and comparing in a second comparator a second reference level higher than the first reference level and producing a second state signal, the first and second reference levels determining a voltage reference range, and switching between the first and second state signals to output the control signal.
27. The method of claim 26, wherein the image is displayed by using the first light during a present frame, when the image is displayed by using the first light during a previous frame and the sensing signal is lower than the second reference level.
28. The method of claim 26, wherein the image is displayed by using the second light during a present frame, when the image is displayed by using the first light during a previous frame and the sensing signal is higher than the second reference level.
29. The method of claim 26, wherein the image is displayed by using the first light during a present frame, when the image is displayed by using the second light during a previous frame and the sensing signal is lower than the first reference level.
30. The method of claim 26, wherein the image is displayed by using the second light during a present frame, when the image is displayed by using the second light during a previous frame and the sensing signal is higher than the first reference level. Description
CROSS-REFERENCE OF RELATED APPLICATIONS The present application claims priority from Korean Patent Application No. 2003-93836, filed on Dec. 19, 2003, the disclosure of which is hereby incorporated herein by reference in its entirety.
The present invention relates to a display apparatus and a method of driving the display apparatus. More particularly, the present invention relates to a display apparatus capable of controlling an operation of a light generating part and reducing power consumption thereof and a method of driving the display apparatus.
A display apparatus, generally, includes a display panel displaying an image using a light. The light may be an externally provided light such as a sunlight, an illumination light, etc., or an internally provided light generated from a backlight, a front-light, etc.
The display apparatus displays the image using the externally provided light and the internally provided light. The display apparatus displays the image using the externally provided light in a bright place, and displays the image using the internally provided light in a dark place.
A power consumption of the backlight assembly may be about 70% of the power consumption of the display apparatus. A backlight assembly having low power consumption is in demand for a portable display device such as a cellular phone, a notebook computer, personal digital assistants (PDA), etc.
When the power consumption of the backlight assembly decreases, the amount of the light generated from the backlight assembly also decreases, thereby decreasing luminance of the display apparatus.
BRIEF SUMMARY OF THE INVENTION The present invention provides a display apparatus capable of controlling an operation of a light generating part and reducing power consumption thereof.
The present invention also provides a method of driving the above-mentioned display apparatus.
A display apparatus in accordance with one exemplary embodiment of the present invention includes a light generating part, a first driving part, a display panel, a sensing part and a second driving part. The light generating part generates a first light based on a first control signal. The first driving part outputs a panel driving signal. The display panel is disposed on the light generating part to receive the first light that is generated from the light generating part or a second light that is provided from an exterior to display an image based on the panel driving signal. The sensing part is disposed on the display panel to output a sensing signal based on the second light that is provided from an exterior to the display panel. The second driving part is disposed between the sensing part and the light generating part to compare a reference voltage range with the sensing signal to output the first control signal. The voltage range is determined based on a first reference voltage and a second reference voltage higher than the first reference voltage.
A method of manufacturing in accordance with one exemplary embodiment of the present invention is provided. A first light is generated based on a control signal. A panel driving signal is outputted. The first light or a second light is received to display an image based on the panel driving signal. The second light is provided from an exterior to display an image. A sensing signal is outputted based on the second light. The sensing signal is compared with a first reference level and a second reference level higher than the first reference level to output the control signal. The first and second reference levels determine a voltage reference range.
Therefore, the light generating part is turned on/off based on the amount of the second light to decrease the power consumption of the light generating part. In addition, number of the turning on/off is decreased to stabilize the operation of the light generating part.
FIG. 2 is a plan view showing a liquid crystal display (LCD) apparatus according to an exemplary embodiment of the present invention;
FIG. 3 is a cross-sectional view taken along the line I-I′ shown in FIG. 2;
FIG. 4 is a circuit diagram showing an LCD apparatus according to an exemplary embodiment of the present invention;
FIG. 5 is a circuit diagram showing a light sensing part according to an exemplary embodiment of the present invention;
FIG. 6 is a timing diagram showing an output signal of a gate driving integrated circuit (IC) and a light sensing part according to an exemplary embodiment of the present invention;
FIG. 7 is a block diagram showing a second driving part according to an exemplary embodiment of the present invention;
FIG. 8 is a circuit diagram showing a first comparator and a second comparator; and
FIG. 9 is a timing diagram showing an output signal of a second driving part according to an exemplary embodiment of the present invention.
FIG. 1 is a block diagram showing a display apparatus according to an exemplary embodiment of the present invention.
Referring to FIG. 1, the liquid crystal display (LCD) apparatus 700 includes an LCD panel 100 displaying an image, a first driving part 200 outputting a panel driving signal PDS that drives the LCD panel 100, a light generating part 300 supplying the LCD panel 100 with an internally provided light L1 and a second driving part 600 driving the light generating part 300.
The LCD panel 100 includes a light sensing part 400 outputting a photo current Iph based on an amount of an externally provided light L2 that is supplied from an exterior to the LCD panel 100. The second driving part 600 outputs a first control signal CS1 driving the light generating part 300 based on the photo current Iph outputted from the light sensing part 400.
When the externally provided light L2 is insufficient to display the image, the light sensing part 400 outputs the photo current Iph based on the insufficient externally provided light L2 so that the second driving part 600 outputs the first control signal corresponding to the insufficient externally provided light L2. Therefore, the light generating part 300 generates the internally provided light L1 based on the first control signal CS1 corresponding to the insufficient externally provided light L2 so that the LCD panel 100 displays an image using the internally and externally provided lights L1 and L2.
When the externally provided light L2 is sufficient to display the image, the light sensing part 400 outputs the photo current Iph based on the sufficient externally provided light L2 so that the second driving part 600 outputs the first control signal corresponding to the sufficient externally provided light L2. Therefore, the light generating part 300 does not generate the internally provided light L1 based on the first control signal CS1 corresponding to the sufficient externally provided light L2 so that the LCD panel 100 displays the image using the externally provided light L2.
The LCD apparatus 700 turns on/off the light generating part 300 based on a variation of the amount of the externally provided light L2. Therefore, a power consumption of the LCD apparatus 700 is decreased. In addition, the LCD apparatus 700 may display the image of an improved display quality in a dark place although the power consumption of the LCD apparatus 700 is decreased.
FIG. 2 is a plan view showing a liquid crystal display (LCD) apparatus according to an exemplary embodiment of the present invention, and FIG. 3 is a cross-sectional view taken along the line I-I′ shown in FIG. 2.
Referring to FIGS. 2 and 3, the LCD panel 100 includes a lower substrate 110, an upper substrate 120 corresponding to the lower substrate 110, a liquid crystal layer 130 interposed between the lower and upper substrates 110 and 120, and a sealant 135.
The LCD panel 100 includes a display area DA where the image is displayed and first to fourth peripheral areas PA1, PA2, PA3 and PA4 are disposed at a position adjacent to the display area DA.
The upper substrate 120 includes a blocking layer 121, a color filter 122 and a common electrode 123.
The color filter 122 includes a red color filter unit corresponding to a red color, a green color filter unit corresponding to a green color and a blue color filter unit corresponding to a blue color. The blocking layer 121 is disposed between the color filter units in the display area DA to improve the display quality of the LCD apparatus 700. In addition, the blocking layer 121 is also disposed in a position corresponding to the first to fourth peripheral areas PA1, PA2, PA3 and PA4. The common electrode 123 is uniformly formed in thickness on the blocking layer 121 and the color filter 122.
A plurality of pixel portions PP is arranged in a matrix shape on the lower substrate 110 corresponding to the display area DA. The pixel portions PP are defined by a plurality of gate lines GL1, GL2, . . . GLn extended in a first direction D1 and a plurality of data lines DL1, DL2, . . . DLn extended in a second direction D2.
Each of the pixel portions PP includes a pixel thin film transistor TR1 and a pixel electrode PE. The pixel thin film transistor TR1 includes a first gate electrode GE1 electrically connected to one of the gate lines, a first source electrode SE1 electrically connected to one of the data lines, and a first drain electrode DE1 electrically connected to the pixel electrode PE. The pixel electrode PE corresponds to the common electrode 123, and the liquid crystal layer 130 is disposed between the pixel electrode PE and the common electrode 123 to form a liquid crystal capacitor Clc.
The first peripheral area PA1 is disposed at a position adjacent to first end portions of the gate lines GL1, GL2, . . . GLn, and the second peripheral area PA2 is disposed at a position adjacent to the second end portions of the gate lines GL1, GL2, . . . GLn corresponding to the first end portions. The third peripheral area PA3 is also disposed at a position adjacent to the third end portions of the data lines DL1, DL2, . . . DLm, and the fourth peripheral area PA4 is disposed at a position adjacent to the fourth end portions of the data lines DL1, DL2, . . . DLm corresponding to the third end portions.
The first driving part 200 driving the LCD panel 100 includes a gate driving integrated circuit 210 disposed in the first peripheral area PA1 and a data driving integrated circuit 220 disposed in the third peripheral area PA3.
The gate driving integrated circuit 210 is electrically connected to the first end portions of the gate lines GL1, GL2, . . . GLn in the first peripheral area PA1 to successively output gate signals to the gate lines GL1, GL2, . . . GLn. Alternatively, the gate driving integrated circuit 210 may include amorphous silicon so that the gate driving integrated circuit 210 is formed in the first peripheral area PA1 of the lower substrate 110. Alternatively, the gate driving integrated circuit 210 may be directly formed on the lower substrate 110. The gate driving integrated circuit 210 may also be formed in one of the first to fourth peripheral areas PA1, PA2, PA3 and PA4. The gate driving integrated circuit 210 may also be formed from a same layer as the thin film transistors. When the gate driving integrated circuit 210 is formed in one of the first to fourth peripheral areas PA1, PA2, PA3 and PA4, a center of the display area DA may be disposed at a center of the LCD panel 100. The data driving integrated circuit 220 is electrically connected to the third end portions of the data lines DL1, DL2, . . . DLm in the third peripheral region PA3 to output data signals to the data lines DL1, DL2, . . . DLm. Alternatively, the gate driving integrated circuit 210 and the data driving integrated circuit 220 may form a one chip.
The light sensing part 400 is disposed in a side portion SP of the display area DA adjacent to the fourth peripheral area PA4. The light sensing part 400 outputs the photo current Iph based on the amount of the externally provided light L2 that is provided from an exterior to the LCD panel 100. The photo current Iph varies in proportion to the amount of the externally provided light L2. That is, the photo current Iph increases when the amount of the externally provided light L2 increases. The photo current Iph decreases when the amount of the externally provided light L2 decreases. Alternatively, the sensing part 400 may include amorphous silicon. The light sensing part 400 may be directly formed on the lower substrate 110, and the light sensing part 400 may be formed from the same layer as the thin film transistors, the gate lines, the data lines, etc. so that a manufacturing process of the LCD panel 100 may be simplified.
The data driving integrated circuit 220 is electrically connected to the third end portions of the data lines DL1, DL2, . . . DLm. The fourth end portions of the data lines DL1, DL2, . . . DLm are disposed in the display area DA so that the fourth end portions of the data lines DL1, DL2, . . . DLm are not disposed in the fourth peripheral area PA4. Therefore, the light sensing part 400 may not overlapped with the data lines DL1, DL2, . . . DLm though the light sensing part 400 is disposed in the side portion SP of the display area DA. When the light sensing part 400 is not overlapped with the data lines DL1, DL2, . . . DLm, the gate or data signals that are applied to the display area DA may not be distorted.
A flexible circuit board 140 is disposed in the third peripheral area PA3. The flexible circuit board 140 receives signals from an exterior to the LCD panel to apply the gate driving integrated circuit 210, the data driving integrated circuit 220 and the light sensing part 400 with the signals.
FIG. 4 is a circuit diagram showing an LCD apparatus according to an exemplary embodiment of the present invention, and FIG. 5 is a circuit diagram showing a light sensing part according to an exemplary embodiment of the present invention.
Referring to FIG. 4, the light sensing part 400 is disposed in the side portion SP of the display area DA. The gate driving integrated circuits 210 and data driving integrated circuit 220 are disposed in the first and third peripheral areas PA1 and PA3, respectively. The first and third peripheral areas PA1 and PA3 are disposed at a position adjacent to the display area DA.
The gate driving integrated circuit 210 includes a shift resistor having a plurality of stages SRC1, SRC2, . . . , SRCn+1. A plurality of gate lines GL1, GL2, . . . GLn is electrically connected to the stages SRC1, SRC2, . . . , SRCn so that the stages SRC1, SRC2, . . . , SRCn apply the gate signals to the gate lines GL1, GL2, . . . GLn, respectively.
A last stage SRCn+1 of the stages SRC1, SRC2, . . . SRCn+1 is a dummy stage that drives an n-th stage SRCn.
A first driving voltage line VONL and a second driving voltage line VOFFL are extended in the first direction D1, and are disposed in the first peripheral area PA1 adjacent to the gate driving integrated circuit 210. A start signal ST is applied to the first stage SRC1 through the start signal line STL. The start signal line STL is disposed at a position adjacent to the first driving voltage line VONL.
Referring to FIGS. 4 and 5, the light sensing part 400 includes a plurality of sensing thin film transistors TR2 and a plurality of first storage capacitors Cs1.
Each of the sensing thin film transistors TR2 includes a second gate electrode GE2 electrically connected to the second driving voltage line VOFFL, a second drain electrode DE2 electrically connected to the first driving voltage line VONL and a second source electrode SE2 electrically connected to a first read-out line RL1. Each of the first storage capacitors Cs1 includes a first electrode LE1 electrically connected to the second driving voltage line VOFFL and a second electrode UE1 electrically connected to the first read-out line RL1.
A read-out part 500 is disposed in the third peripheral area PA3. The read-out part 500 includes a read-out thin film transistor TR3 and a second storage capacitor Cs2. The read-out thin film transistor TR3 includes a third gate electrode GE3 electrically connected to an output terminal of the last stage SRCn+1, a third drain electrode DE3 electrically connected to the first read-out line RL1 and a third source electrode SE3 electrically connected to the second read-out line RL2. The second storage capacitor Cs2 includes a third electrode LE2 electrically connected to the second driving voltage line VOFFL and a fourth electrode UE2 electrically connected to the second read-out line RL2.
A reset part 550 is disposed in the first peripheral region PA1. The reset part 550 may initialize the sensing part 400 at every predetermined interval. A reset thin film transistor TR4 of the reset part 550 includes a fourth gate electrode GE4 electrically connected to the start signal line STL, a fourth drain electrode DE4 electrically connected to the first read-out line RL1 and a fourth source electrode SE4 electrically connected to the second driving voltage line VOFFL.
FIG. 6 is a timing diagram showing an output signal of a gate driving integrated circuit (IC) and a light sensing part according to an exemplary embodiment of the present invention.
Referring to FIG. 6, when the start signal ST is applied to the first stage SRC1 during a first frame, the first stage SRC1 applies a first gate signal to the first gate line GL1.
Subsequently, the second stage SRC2 outputs a second gate signal to the second gate line GL2 based on the first gate signal outputted from the first stage SRC1. The above described processes are repeated so that the gate signals are applied to the gate lines GL1, GL2, . . . GLn, respectively, during the first frame.
The start signal ST is then applied to the first stage SRC1 to start a second frame. The above described processes are repeated so that the gate signals are applied to the gate lines GL1, GL2, . . . GLn, respectively, during the second frame.
A blank period BL is interposed between the first and second frames. The gate signals applied to the gate lines GL1, GL2, . . . GLn, are discharged during the blank period BL so as to initialize the gate lines GL1, GL2, . . . GLn.
The sensing thin film transistor TR2 outputs the photo current Iph to the second source electrode SE2 based on the externally provided light L2. The first storage capacitor Cs1 receives the photo current Iph that is outputted from the sensing thin film transistor TR2.
When the amount of the externally provided light L2 decreases, the photo current Iph outputted from the sensing thin film transistor TR2 also decreases so that a first voltage V1 charged in the first storage capacitor Cs1 decreases based on the decreased photo current Iph. Therefore, the first voltage V1 is slightly higher than the second driving voltage VOFF during the first frame.
The read-out transistor TR3 is then turned on based on the output signal outputted from the last stage SRCn+1. The read-out thin film transistor TR3 reads the first voltage V1 stored in the first storage capacitor Cs1 so that the second storage capacitor Cs2 receives a second voltage V2 based on the first voltage V1.
The first voltage V1 stored in the first storage capacitor Cs1 is discharged during the blank period BL to form the second driving voltage VOFF.
When the amount of the externally provided light L2 increases, the photo current lph outputted from the sensing thin film transistor TR2 increases. Therefore, the first voltage V1 charged in the first storage capacitor Cs1 based on the increased photo current Iph also increases to the first driving voltage VON.
The read-out thin film transistor TR3 is then turned on based on the output signal outputted from the last stage SRCn+1. Therefore, the read-out thin film transistor TR3 reads the first voltage V1 stored in the first storage capacitor Cs1 so that the second storage capacitor Cs2 receives the second voltage V2 based on the first voltage V1.
FIG. 7 is a block diagram showing a second driving part according to an exemplary embodiment of the present invention, and FIG. 8 is a circuit diagram showing a first comparator and a second comparator.
Referring to FIGS. 7 and 8, the second driving part 600 includes a first comparator 610, a second comparator 620, a memory part 630 and a switching part 640.
The first comparator 610 receives the second voltage V2 outputted from the read-out part 500, and includes a first operational amplifier OP-AMP that compares the second voltage V2 with a first reference voltage VREF1 to output a first state voltage VSE1. The first reference voltage VREF1 is a minimum voltage of a reference voltage range. When the second voltage V2 is higher than the first reference voltage VREF1, the first state voltage VSE1 has a first voltage level V+. When the second voltage V2 is lower than the first reference voltage VREF1, the first state voltage VSE1 has a second voltage level V−.
The second comparator 620 receives the second voltage V2 outputted from the read-out part 500, and includes a second operational amplifier OP-AMP that compares the second voltage V2 with a second reference voltage VREF2 to output a second state voltage VSE2. The second reference voltage VREF2 is a maximum voltage in the reference voltage range. When the second voltage V2 is higher than the second reference voltage VREF2, the second state voltage VSE2 has the first voltage level V+. When the second voltage V2 is lower than the second reference voltage VREF2, the second voltage VSE2 has the second voltage level V−.
The first and second reference voltages VREF1 and VREF2 may be adjusted to prevent a noise signal generated from the externally provided light L2. Alternatively, the first and second reference voltages VREF1 and VREF2 may be also adjusted based on a sensitivity of the light sensing part 400.
A memory part 630 outputs a second control signal CS2 that is outputted from the switching part 640 and corresponds to a previous frame. The memory part 630 stores a first control signal CS1 that is outputted from the switching part 640 and corresponds to a present frame. The second control signal CS2 is the on/off signal that turns on/off the light generating part 300, and corresponds to a state of the light generating part 300.
The switching part 640 receives the first state voltage VSE1 outputted from the first comparator 610, the second state voltage VSE2 outputted from the second comparator 620 and the second control signal CS2 outputted from the memory part 630.
Table 1 represents digitalized signals including input and output signals of the switching part 640.
Referring to Table 1, when the first and second control signals CS1 and CS2 are in a low state (0), the light generating part 300 is turned off. When the first and second control signals CS1 and CS2 are in a high state (1), the light generating part 300 is turned on.
A first state signal (D-low) is digitalized signal of the first state voltage VSE1. That is, when the first state signal (D-low) is in the low state (0), the first state voltage VSE1 has the first voltage level (V+). In addition, when the first state signal (D-low) is in the high state (1), the first state voltage VSE1 has the second voltage level (V−).
A second state signal (D-high) is the digitalized signal of the second state voltage VSE2. That is, when the second state signal (D-high) is in the low state (0), the second state voltage VSE2 has the first voltage level (V+). In addition, when the second state signal (D-high) is in the high state (1), the second state voltage VSE2 has the second voltage level (V−).
Referring again to the Table 1, when the second control signal CS2 is in the low state (0), that is the light generating part 300 is turned off during the previous frame and the first state signal (D-low) and the second state signal (D-low) are in the low state (0), the first control signal CS1 outputted from the switching part 640 is in the low state (0) that is substantially same as the second control signal CS2. Therefore, the light generating part 300 maintains the off state of the previous frame during the present frame, when the second voltage V2 outputted from the read-out part 500 is higher than the first and second reference voltages VREF1 and VREF2.
When the second control signal CS2 is in the low state (0) and the first state signal (D-low) is in the low state (0) and the second state signal (D-high) is in the high state (1), the first control signal CS1 outputted from the switching part 640 is in the low state (0) that is substantially same as the second control signal CS2. Therefore, the light generating part 300 maintains the off state of the previous frame during the present frame, when the second voltage V2 is higher than the first reference voltage VREF1 and lower than the second reference voltage VREF2.
When the second control signal CS2 is in the low state (0), and the first state signal (D-low) and the second state signal (D-high) are in the high state (1), the first control signal CS1 outputted from the switching part 640 is in the high state (1) that is opposite to the second control signal CS2. Therefore, the light generating part 300 is turned on during the present frame, when the second voltage V2 is higher than the first and second reference voltages VREF1 and VREF2.
When the second control signal CS2, that is, the light generating part 300 is turned on during the previous frame, and the first state signal (D-low) and the second state signal (D-high) are in the low state (0), the first control signal CS1 outputted from the switching part 640 is in the low state (0) that is opposite to the second control signal CS2. Therefore, the light generating part 300 is turned off during the present frame.
When the second control signal CS2 is in the high state (1), and the first state signal (D-low) is in the low state (0) and the second state signal (D-high) is in the high state (1), the first control signal CS1 outputted from the switching part 640 is in the high state (1) that is substantially the same as the second control signal CS2. Therefore, the light generating part 300 maintains the on-state of previous frame during the present frame.
When the second control signal CS2 is in the high state (1) and the first state signal (D-low) and the second state signal (D-high) are in the high state (1), the first control signal CS1 outputted from the switching part 640 is in the high state (1) that is substantially same as the second control signal CS2. Therefore, the light generating part 300 maintains the on-state of the previous frame during the present frame.
When the first state signal (D-low) is in the high state (1), the second state (D-high) may not be in the low state (0).
FIG. 9 is a timing diagram showing an output signal of a second driving part according to an exemplary embodiment of the present invention. A horizontal axis represents a voltage and the on/off state of the light generating part 300.
Referring to FIG. 9, the first graph GRP1 shows an operation of the light generating part 300 during a present frame in case that the light generating part 300 is turned off during a previous frame.
Referring to the first graph GRP1 in the FIG. 9, the light generating part 300 is turned off during the present frame, when the light generating part 300 is turned off during the previous frame and the second voltage V2 is lower than the second reference voltage VREF2 during the present frame. In addition, the light generating part 300 is turned on, when the light generating part 300 is turned off during the previous frame and the second voltage V2 is higher than the second reference voltage VREF2 during the present frame.
Referring to FIG. 9, the second graph GRP2 shows the operation of the light generating part 300 during the present frame in case that the light generating part 300 is turned on during the previous frame.
Referring to the second graph GRP2 in the FIG. 9, the light generating part 300 is turned on, when the light generating part 300 is turned on during the previous frame and the second voltage V2 is higher than the first reference voltage VREF1 during the present frame. In addition, the light generating part 300 is turned off, when the light generating part 300 is turned off during the previous frame and the second voltage V2 is lower than the second reference voltage VREF1 during the present frame.
According to the present invention, the second driving part receives the second voltage corresponding to the externally provided light, and compares the second voltage with the first and second reference voltages that determine the reference voltage range to output the first control signal that operates the light generating part.
Therefore, the light generating part is turned on/off based on the amount of the externally provided light so as to reduce the power consumption of the display apparatus.
The second driving part also compares the second voltage with the reference voltages to output the first control signal based on the on/off state of the light generating part during the previous frame.
Furthermore, the number of the turning on/off is decreased to stabilize the operation of the light generating part by using the reference voltage range defined by the first and second reference voltages, although the amount of the externally provided light may be close to a predetermined reference amount, thereby increasing a lifetime of the light generating part.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS5786801 *Sep 6, 1996Jul 28, 1998Sony CorporationBack light control apparatus and method for a flat display systemUS5933089 *Dec 16, 1996Aug 3, 1999Nec CorporationPager with message display functionUS6888528 *Jun 25, 1999May 3, 2005Sanyo Electric Co., Ltd.Liquid crystal display apparatus having light collecting mechanismUS20030137485 *Jun 12, 2002Jul 24, 2003Chung-Kuang WeiTFT-LCD capable of adjusting its light sourceUS20050179682 *Dec 16, 2004Aug 18, 2005Kyoung-Ju ShinDisplay apparatus* Cited by examinerReferenced byCiting PatentFiling datePublication dateApplicantTitleUS7974103 *Aug 13, 2007Jul 5, 2011Samsung Electronics Co., Ltd.LCD signal transfer membersUS20110025678 *Feb 23, 2010Feb 3, 2011Samsung Mobile Display Co., Ltd.Organic light emitting display device and driving method thereof* Cited by examinerClassifications U.S. Classification345/102, 315/154, 315/307, 345/212, 315/156, 345/211, 345/207, 345/87, 345/89International ClassificationG09G3/20, G02F1/133, G09G3/34, G09G3/36, H05B37/02Cooperative ClassificationG09G2360/144, G09G3/3677, G09G2320/0626, G09G2330/021, G09G3/3406European ClassificationG09G3/34BLegal EventsDateCodeEventDescriptionSep 17, 2012ASAssignmentEffective date: 20120904Owner name: SAMSUNG DISPLAY CO., LTD., KOREA, REPUBLIC OFFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:SAMSUNG ELECTRONICS CO., LTD.;REEL/FRAME:029045/0860May 9, 2012FPAYFee paymentYear of fee payment: 4Sep 24, 2004ASAssignmentOwner name: SAMSUNG ELECTRONICS CO., LTD., KOREA, REPUBLIC OFFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:KIM, JIN-HONG;PARK, CHEOL-WOO;CHAI, CHONG-CHUL;AND OTHERS;REEL/FRAME:015838/0826Effective date: 20040913RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google