JP2006106144A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device capable of reducing disorder of display nearby spacers. <P>SOLUTION: A display panel 10 has spacers SP arranged between a face plate FP and a rear plate RP almost in parallel to scanning lines. Temperature sensors 16 and 17 detect temperatures of the rear plate RP and face plate FP and a microcomputer 42 obtains the temperature difference between the both. Then the microcomputer 42 controls a scanning line driver 31 according to the temperature difference between the rear plate RP and face plate FP to vary a scanning line signal supplied to 1st scanning lines (Y5, Y6, Y10, etc.). Consequently, the disorder of display of display pixels Px nearby the spacers SP can be eliminated. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a display device in which a spacer is disposed between substrates such as a field emission display.

Development of a field emission display in which an electron-emitting device (hereinafter referred to as an electron source) and a phosphor are arranged between two substrates and the phosphor emits light by electrons emitted from the electron source to display. (See Patent Document 1).
In order to operate the field emission display, it is necessary to reduce the pressure between the substrates. For this reason, spacers are arranged between the substrates to counter atmospheric pressure, and the distance between the substrates is maintained.
JP 2000-31607 A

However, the display may be disturbed in the vicinity of the spacer due to charging of the spacer or the like.
The present invention has been made to solve such a problem, and an object of the present invention is to provide a display device that can reduce display disturbance in the vicinity of a spacer.

  In order to achieve the above-described object, a display device of the present invention includes a first substrate, a second substrate disposed opposite to the first substrate, and a plurality of signal lines and scanning lines arranged in a matrix, A display unit including a spacer disposed between the first substrate and the second substrate and substantially parallel to the scanning line, and a temperature difference detection for detecting a temperature difference between the first substrate and the second substrate. The scanning line signal is supplied to each of the first scanning line disposed in the vicinity of the spacer, and the second scanning line disposed from the spacer with the first scanning line separated from the spacer. A scanning line driving unit for displaying a display unit, and a temperature difference storing correction information for varying a scanning line signal supplied to the first scanning line in accordance with a temperature difference between the first substrate and the second substrate Detected by the correction information storage means and the temperature difference detection means The scanning line driving unit is controlled to supply a scanning line signal to the first scanning line based on the correction information stored in the temperature difference correction information storage unit according to the temperature difference between the first substrate and the second substrate. And a control unit.

  The display device of the present invention includes a first substrate, a second substrate disposed opposite to the first substrate, and a plurality of signal lines and scanning lines arranged in a matrix, and between the first substrate and the second substrate. And a temperature difference detecting means for detecting a temperature difference between the first substrate and the second substrate, and a plurality of scanning lines. A scanning line driving unit for displaying the display unit by supplying a scanning line signal to a first scanning line disposed in the vicinity of the spacer and a second scanning line disposed at a distance from the spacer to the first scanning line. And the scanning line drive unit to vary the voltage of the scanning line signal supplied to the first scanning line according to the temperature difference between the first substrate and the second substrate detected by the temperature difference detection means. And a control unit for controlling.

  ADVANTAGE OF THE INVENTION According to this invention, the display apparatus which can reduce the disorder of the display in the spacer vicinity can be provided.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram illustrating a display device D according to an embodiment of the present invention.
The display device D according to the present invention includes a display panel 10, a signal line driver 20, a scanning line driver 30, a video signal processing circuit 40, and a timing generation circuit 60.

  A video signal and a synchronization signal are input to the input circuit 50, and are output separately to the video signal processing circuit 40 and the timing generation circuit 60. The video signal processing circuit 40 corrects a digital signal having a certain gradation value input from the input circuit 50 and outputs the corrected digital signal to the signal line driver 20. The timing generation circuit 60 outputs operation timing based on the synchronization signal input from the input circuit 50 to the scanning line driver 30, the video signal processing circuit 40, and the signal line driver 20.

  The signal line driver 20 converts the video signal input from the video signal processing circuit 40 into a drive signal and outputs it to the display panel 10. The scanning line driver 30 converts the operation timing input from the timing generation circuit 60 into a scanning line signal and outputs it to the display panel 10. The display panel 10 displays an image based on the drive signal and the scan line signal input from the signal line driver 20 and the scan line driver 30.

2 is a top view schematically showing the state of the display panel 10 as viewed from above, and FIG. 3 is a side view of the state of the display panel 10 as viewed from the side.
As shown in FIGS. 2 and 3, the display panel 10 is an electronic device in which signal wiring such as a face plate FP, a scanning line Y, and a signal line X as a transparent substrate (first substrate) that transmits light is formed. A rear plate RP, a side wall W, a spacer SP, a display pixel Px, temperature sensors 16, 17 and the like as a source substrate (second substrate) are provided.

The face plate FP and the rear plate RP together with the side wall W constitute a vacuum vessel. In other words, the space (inside the vacuum vessel) formed by the face plate FP, the rear plate RP, and the side wall W is decompressed for the operation of the display panel 10 and is in a high vacuum state.
The spacer SP is used to keep the space between the face plate FP and the rear plate RP. Since the pressure between the face plate FP and the rear plate RP is reduced, a force due to atmospheric pressure is applied, and there is a possibility that the distance between these centers is smaller than the vicinity of the side wall W. Therefore, the spacer SP has a columnar shape having a substantially rectangular bottom surface elongated in the horizontal direction, and is arranged substantially parallel to the scanning line Y at a predetermined interval.

On the rear plate RP, a plurality of signal lines X are arranged in the X-axis direction (vertical direction in the drawing), and the scanning lines Y are arranged in a direction orthogonal to the signal lines X, that is, in the Y-axis direction. That is, the signal lines X and the scanning lines Y are arranged in a matrix so as to intersect. m (= 720) scanning lines Y (Y1 to Ym) extend in the horizontal (horizontal) direction. n (= 1280 × 3) signal lines X (X1 to Xn) extend in the vertical (vertical) direction across the scanning lines Y1 to Ym.
Near the intersecting positions of the scanning lines Y1 to Ym and the signal lines X1 to Xn, m × n (= about 2.76 million) display pixels Px are arranged.

The temperature sensor 16 is provided on the face plate FP and detects the temperature of the face plate FP itself. The temperature sensor 17 is provided on the surface of the rear plate RP, and detects the temperature of the rear plate RP itself. These temperature sensors 16 and 17 are, for example, thermistors. The temperature signals detected by the temperature sensors 16 and 17 are input to the microcomputer 42, and the microcomputer 42 calculates the temperature difference between them. That is, the temperature sensors 16 and 17 and the microcomputer 42 constitute temperature difference detection means. As the temperature difference detecting means, a thermocouple, a platinum resistance thermometer, or the like can be used.
The microcomputer 42 serves as a control unit that controls the scanning line driver 30 so as to vary the voltage of the scanning line signal supplied to the scanning lines in the vicinity of the spacer SP according to the detected temperature difference between the face plate FP and the rear plate RP. Function.

The display pixel Px is generated from the electron emitter 11 as an electron source and the phosphor 12. The electron-emitting devices 11 are arranged at intersections of a plurality of signal lines X and scanning lines Y arranged in a matrix on the rear plate RP, and are driven by the corresponding scanning lines Y and signal lines X to emit electrons. To do.
The phosphor 12 is disposed on the face of the face plate FP that faces the electron emitter 11 and emits light by an electron beam emitted from the electron emitter 11. The phosphor 2 emits light in one of red (R), green (G), and blue (B) display colors. That is, the display pixel Px corresponds to one of the display colors of red (R), green (G), and blue (B).
The display pixels Px of red (R), green (G), and blue (B) are each arranged in the vertical direction (X direction). Here, the three adjacent display pixels Px of red (R), green (G), and blue (B) arranged in the horizontal direction can be considered as one color pixel. By controlling these red (R), green (G), and blue (B) display pixels Px, full color display is possible.

  The display pixels Px are arranged between the spacers SP as shown in FIG. In FIG. 2, for the sake of clarity, five display pixels Px are arranged between the spacers SP arranged in the vertical direction, but this is not absolute. A larger number of display pixels Px may be arranged between the spacers SP. Further, the number of display pixels Px arranged between the spacers SP may not be constant.

  That is, the display panel 10 is disposed so as to face the face plate FP having the phosphor 12 disposed on one surface thereof, and the surface of the face plate FP having the phosphor 12 disposed thereon, and the plurality of signal lines X and A rear plate RP in which the scanning lines Y are arranged in a matrix in the X-axis direction and the Y-axis direction, and an electron-emitting device 11 that emits electrons to the phosphor 12 is formed at the intersection of each other, and the face plate FP and the rear plate RP A spacer SP disposed substantially parallel to the scanning line Y formed in the Y-axis direction is provided therebetween.

Here, the display on the display panel 10 is disturbed in the vicinity of the spacer SP. The display pixel (reproximity display pixel) Px closest to the spacer SP, that is, the display pixel Px corresponding to the scanning lines Y5, Y6, Y10, and Y11 in FIG. 2, tends to be darker than the original luminance. Further, the display pixels (proximity display pixels) Px farther from the spacer SP than the near-neighbor display pixels Px, and the display pixels Px corresponding to the scanning lines Y4, Y7, Y9 and the like in FIG. 2 tend to be brighter than the original luminance. The display pixel Px further away from the spacer SP emits light with the original luminance.
When the area on the display panel 10 is divided into the closest area, the adjacent area, and the normal area according to the distance from the spacer SP, the luminance becomes low, high, and normal, and bright and dark stripes are formed in the vicinity of the spacer SP. Will be. Such stripes are not preferable because the display on the display panel 10 is disturbed.
In the above description, the display pixels Px included in these areas are described as one. However, a plurality of display pixels Px may be included in these areas, and low-luminance and high-luminance areas may be included. There may be a display pixel Px having an intermediate brightness therebetween.

The occurrence of light and dark in the vicinity of the spacer SP can be explained by the charging of the spacer SP.
When a part of the electrons emitted from the electron-emitting device 11 in the vicinity of the spacer SP collides with the spacer SP, or when ions such as gas ionized by the action of the emitted electrons adhere to the spacer SP, the spacer SP May be charged. Furthermore, there is a possibility that the electrons that have reached the face plate FP are partially reflected and scattered, and a part of the electrons collides with the spacer SP, thereby charging the spacer SP.

When the spacer SP is charged, the trajectory of electrons traveling from the electron emitting element 11 to the phosphor 12 is affected. For example, when the spacer SP is negatively charged, electrons flying near the spacer SP are separated from the spacer. As a result, the number of electrons reaching the phosphor 12 nearest to the spacer SP decreases, and the number of electrons reaching the phosphor 12 farther from the spacer SP than the nearest phosphor 12 increases. As a result, the display pixel Px in the nearest region has a low luminance and the display pixel Px in the vicinity region has a high luminance with respect to the spacer SP.
In order to suppress the charging of the spacer SP, it is conceivable to impart conductivity to the surface of the spacer SP and remove the charged charge. However, it is difficult to completely eliminate the luminance disturbance in the vicinity of the spacer SP. It is preferable to correct the luminance by some means.

Furthermore, it has been found that the disturbance of the display pixel Px in the vicinity of the spacer SP also occurs due to the influence of the temperature difference between the face plate FP and the rear plate RP.
FIG. 4 is a temperature characteristic diagram showing a relative relationship between the temperature difference (FP-RP) between the face plate FP and the rear plate RP and the position where the electrons hit the phosphor 12.
In this temperature characteristic diagram, the horizontal axis shows the temperature difference (FP-RP) between the face plate FP and the rear plate RP, and the vertical axis shows the position where the electrons hit the phosphor 12.
This temperature characteristic diagram is a fluorescence in which the position at which the electron beam hits the phosphor 12 is changed by a change in the temperature difference between the face plate FP and the rear plate RP with reference to a reference value of the temperature difference, for example, 0 ° C. with no temperature difference. As the temperature difference increases, it can be seen that the deviation from the reference position where the electrons hit the phosphor 12 increases. Although the reference value of the temperature difference has been described as 0 ° C, this is only an example, and a temperature difference other than 0 ° C, for example, + 5 ° C may be used as the reference value.

In such a temperature characteristic, the scanning line Y that constitutes the display pixel Px closest to the spacer SP, that is, the scanning lines Y5, Y6, Y10, and Y11 arranged almost in parallel in the immediate vicinity of the spacer SP becomes dark. The adjacent scanning lines Y4, Y7, Y9, etc. tend to become brighter. This is because, for example, electrons emitted from the electron-emitting device 11 located in the immediate vicinity of the spacer SP bend as the temperature difference increases, the number hitting the corresponding phosphor 12 decreases, and the number hitting the adjacent phosphor 12 increases. Therefore, it can be considered. In addition, a fine shape change equalization in the discharge space due to the temperature difference can be considered.
For this reason, a device that does not cause a temperature difference between the face plate FP and the rear plate RP or a luminance disturbance of the display pixel Px that occurs in the vicinity of the spacer SP due to a change in the temperature difference is eliminated or corrected by some means. Is preferred.

The signal line driver 20, the scanning line driver 30, the video signal processing circuit 40, the input circuit 50, and the timing generation circuit 60 are used as a drive circuit for the display panel 10 and are arranged around the display panel 10. The signal line driver 20 is connected to the signal lines X1 to Xn, and the scanning line driver 30 is connected to the scanning lines Y1 to Ym.
The input circuit 50 receives an analog RGB video signal and a synchronization signal supplied from an external signal source, supplies the video signal to the video signal processing circuit 40, and supplies the synchronization signal to the timing generation circuit 60.
The video signal processing circuit 40 performs signal processing on the video signal from the input circuit 50.
The timing generation circuit 60 takes the operation timing of the signal line driver 20, the scanning line driver 30, and the video signal processing circuit 40 based on the synchronization signal.

The video signal processing circuit 40 includes an AD conversion circuit 41, a microcomputer 42, a correction table 43, a multiplier 44, a conversion unit 45, and a conversion table 46.
The AD conversion circuit 41 converts the analog RGB video signal supplied from the input circuit 50 into a digital format in synchronization with the horizontal synchronization signal. In the AD conversion circuit 41, the analog RGB video signal is converted into 10-bit gradation data that can display, for example, 1024 gradations for each display pixel Px.

  The microcomputer 42 receives the temperature signals from the temperature sensors 16 and 17, calculates the temperature difference between them, and refers to the correction table 43 when the temperature difference between the face plate FP and the rear plate RP is detected. Then, the correction information (numerical value) corresponding to the temperature difference is read, and at least the voltage control signal Vc3 is scanned among the scanning voltage control signals Vc1 to Vc3 for correcting the luminance of the display pixel Px based on the correction information (numerical value). The voltage is output to the voltage control terminal Vyon and the scanning line driver 30 is controlled to correct the luminance of the corresponding display pixel Px.

The scanning line driver 30 includes a shift register 31 and an output buffer amplifier 32.
The shift register 31 shifts the vertical synchronization signal every one horizontal scanning period and outputs it from one of the m output terminals. The output buffer amplifier 32 outputs the scanning line signals to the scanning lines Y1 to Ym in response to the pulses from the m output terminals of the shift register 31, respectively.
The scanning line driver 30 outputs the scanning line signal to the scanning lines Y1 to Ym for one horizontal scanning period in accordance with the scanning voltage control signals Vc1 to Vc3 input from the scanning voltage control terminal Vyon. The scanning line signal is a negative (minus :-) rectangular wave voltage.

  When the position of the spacer SP is used as a reference, the plurality of scanning lines Y1 to Ym are arranged in the first scanning line group (Y5, Y6, Y10, Y11,... Ym-5, Ym- 4) and a second scanning line group (Y1 to Y4, Y7 to Y9, Y12 to..., Ym-3 to Ym) arranged at a position separating the first scanning line from the spacer SP.

  The first scanning line group (Y5, Y6, Y10, Y11,... Ym-5) arranged at the position closest to the spacer SP is significantly affected by the change in temperature difference between the face plate FP and the rear plate RP. , Ym-4), and when a temperature difference occurs, it is necessary to control the drive separately from the second scanning line group (Y1 to Y4, Y7 to Y9, Y12 to..., Ym-3 to Ym). .

  Therefore, the display device D is provided with a correction table 43 (see FIG. 5) for correcting the voltage of the scanning line signal supplied to the first scanning line group when a temperature difference occurs. This correction table 43 is a table used for luminance correction control in the microcomputer 42, and what is set here is not the voltage value of the scanning line signal itself.

As shown in FIG. 5, in the correction table 43, the value of the scanning voltage control signal Vc3 to be output according to the temperature difference is set. The value of the scanning voltage control signal Vc3 is increased as the temperature difference is increased, and the luminance is increased because the potential difference from the signal line X is increased.
That is, the correction table 43 varies the scanning line signal supplied to the first scanning lines Y5, Y6, Y10, Y11, etc. via the buffer amplifier 32 according to the temperature difference between the face plate FP and the rear plate RP. The temperature difference correction information storage means stores the correction information.

When the temperature difference occurs, the microcomputer 42 outputs the scanning voltage control signal Vc3 with reference to the correction table 43, and the scanning line driver 30 outputs a plurality of scanning lines Y1 according to the scanning voltage control signal Vc3 input from the microcomputer 42. The first scanning line group (Y5, Y6, Y10, Y11,... Ym-5, Ym-4) arranged at the position closest to the spacer SP among .about.Ym is driven.
That is, the microcomputer 42 increases the first scanning line group (Y5, Y6, Y10, Y10) in a direction in which the potential difference with the drive signal applied to the signal line X increases as the temperature difference increases with respect to the scanning line driver 30. The luminance of the display pixel Px in this portion is increased by controlling the scanning line driver 30 so as to vary the value (negative voltage) of the scanning line signal of Y11,.

  On the other hand, the second scanning line group is a scanning line group (Y4, Y7, Y9, Ym-3) located immediately adjacent to the first scanning line group, and a scanning line that is separated from the spacer SP by two scanning lines or more. Divided into groups (Y1-Y3, Y8, Ym-2, Ym-1, Ym).

The scanning line group (Y1 to Y3, Y8, Ym-2, Ym-1, Ym) that is more than two scanning lines away from the spacer SP is affected by the temperature difference between the face plate FP and the rear plate RP. There is no need for luminance correction.
On the other hand, in the second scanning line group, the scanning line group (Y4, Y7, Y9, Ym-3) located immediately adjacent to the first scanning line group has a slight luminance compared to the others due to the influence of the charging of the spacer SP. In some cases, it becomes brighter, and this requires separate correction control.

Therefore, as a modification of the correction table 43 shown in FIG. 5, temperature correction values of the scanning voltage control signal Vc1 and the scanning voltage control signal Vc2 are added in addition to the scanning voltage control signal Vc3 as shown in FIG. The correction table 43a may be used.
In this correction table 43a, the scanning voltage control signal Vc2 is a constant value such as “1.00”, for example, and there is no change in luminance even if it is output as a control signal for correction. The scanning voltage control signal Vc1 has a lower value than the scanning voltage control signal Vc2, and the smaller the numerical value, the lower the luminance because the potential difference from the signal line X disappears.

In this case, the microcomputer 42 outputs the scanning voltage control signals Vc1, Vc2, and Vc3 with reference to the correction table 43a when the temperature difference occurs.
In accordance with the scanning voltage control signal Vc2 input from the microcomputer 42, the scanning line driver 30 scans a group of scanning lines (Y1 to Y3, Y8, Ym-2, Ym-1) separated from each other by two scanning lines from the spacer SP. , Ym) is driven, but since all the voltages are the same as the original, there is no change in the corresponding display pixel Px.

  The scanning line driver 30 drives the scanning line group (Y4, Y7, Y9, Ym-3) located immediately adjacent to the first scanning line group according to the scanning voltage control signal Vc1 input from the microcomputer 42. The luminance of the display pixel Px is slightly lowered.

  Since the scanning line driver 30 drives the first scanning line group (Y4, Y7, Y9, Ym-3) according to the scanning voltage control signal Vc3 input from the microcomputer 42, the luminance of the corresponding display pixel Px is increased.

That is, the scanning line driver 30 sequentially drives the scanning lines Y1 to Ym using the scanning voltage control signals Vc1 to Vc3 input from the microcomputer 42 through the scanning voltage control terminal Vyon. The signal line driver 20 drives the signal lines X1 to Xn by a voltage pulse type signal line driving signal while each of the scanning lines Y1 to Ym is driven by the scanning line driver 30.
In this way, a negative (−) voltage is supplied from the scanning line driver 30 to the scanning lines Y1 to Ym, and a positive (+) voltage is supplied from the signal line driver 20 to the signal lines X1 to Xn. The display panel 10 is displayed according to the potential difference.

Note that while the temperature difference between the face plate FP and the rear plate RP is extremely small, the display pixel Px may not have uneven brightness. That is, there is a certain allowable range when uneven brightness occurs in the spacer SP arrangement portion of the display panel 10 (see FIG. 4).
Therefore, the microcomputer 42 detects the first scanning line group (Y5, Y6, Y10, Y11,... Ym-5) when the temperature difference between the face plate FP and the rear plate RP exceeds a preset allowable range. The scanning line driver 30 is controlled to vary the value (voltage) of the scanning line signal supplied to Ym-4). For example, in the example of the correction table 43 in FIG. 5, for example, in the example of the correction table 43 in FIG. 5, the value of the scanning voltage control signal Vc3 in the range of ± 10 C ° from the reference value is set to “−1.00”. It is to keep.

As a countermeasure for correcting uneven brightness in the vicinity of the spacer SP when a temperature difference between the face plate FP and the rear plate RP occurs, a predetermined scanning line (first scanning line group Y5, Y5) arranged in the vicinity of the spacer SP as described above is used. Y6, Y10, Y11, a part of the second scanning line group, etc.) may be changed, and correction control may be performed on the signal line X side as well.
In this case, based on the timing signal from the timing generation circuit 60, the microcomputer 42 determines whether the scanning line Y number Yi and the display color are red (R), green (G), or blue (B). Outputs a tone correction signal.
The microcomputer 42 determines the number Yi of the scanning line Y from the vertical synchronization signal, the display color from the horizontal synchronization signal, and determines the gradation correction value by referring to the gradation correction table 47 instead of the correction table 43. .

FIG. 7 is a schematic diagram showing an example of the contents of the gradation correction table 47.
As shown in the figure, the number Yi of the scanning line Y and the respective gradation correction values Ar, Ag, Ab for red (R), green (G), and blue (B) are represented correspondingly. . FIG. 8 is a graph showing the table shown in FIG. The horizontal axis represents the scanning line number Yi, and the vertical axis represents the respective gradation correction values Ar, Ag, Ab for red (R), green (G), and blue (B). FIGS. 7 and 8 show gradation correction values for correcting the relative luminances RLr, RLg, and RLb shown in FIG.
The multiplier 44 multiplies the gradation value output from the AD conversion circuit 41 by the gradation correction value output from the microcomputer 42. As a result of this multiplication, the gradation value is corrected, and unevenness in luminance of each of red (R), green (G), and blue (B) in the vicinity of the spacer SP is corrected.

The conversion unit 45 converts the digital signal having a certain gradation value output from the multiplier 44 into a value suitable for the voltage pulse system of the signal line drive signal. In this conversion, the conversion table 46 is referred to.
The conversion table 46 stores 1024 12-bit conversion data assigned to all the gradation values of the gradation data output from the multiplier 44.

  Specifically, gradations 0-256 are 0-256, gradations 257-512 are 512-769, gradations 513-768 are 1024-1280, gradations 769-1024 are 1536-1792, respectively. Convert. In this conversion result, the upper 3 bits and the lower 9 bits respectively correspond to the pulse amplitude (element voltages V1 to V4) and the pulse width (time length of 0 to 256) of the signal line drive signal. The signal line drive signal will be described later with reference to FIG.

The signal line driver 20 includes line memories 21 and 22 and a drive signal generation unit 23.
The line memory 21 samples the video signal for one horizontal line in synchronization with the clock CK1 supplied from the timing generation circuit 60 in each horizontal scanning period, and these video signals, that is, n pieces of gradation data are parallelly sampled. Output.
The line memory 22 latches the gradation data in response to the latch pulse DL supplied from the timing generation circuit 60 in a state where all the gradation data is output from the line memory 21, and the line memory 21 performs the sampling operation again. The gradation data is held in the subsequent one horizontal scanning period.

  The drive signal generator 23 generates n voltage pulses having pulse amplitudes and pulse widths respectively corresponding to the gradation data output in parallel from the line memory 22 as signal line drive signals to generate signal lines X1 to Xn. To supply. The drive signal generator 23 includes a counter 24, n pulse width modulation circuits 25, and n output buffer amplifiers 26.

  The counter 24 has a 10-bit configuration, and is initialized in response to a reset signal RST supplied from the timing generation circuit 60 with the start of each horizontal scanning period. The counter 24 is counted up by the clock CK2 supplied from the timing generation circuit 60 following the reset signal RST. Thereafter, the counter 24 outputs 10-bit count data representing the effective video period in each horizontal scanning period by a time length of 1024 stages.

  Each pulse width modulation circuit 25 is a comparator, for example, and compares the corresponding gradation data supplied from the line memory 22 with the count data supplied from the counter 24 until the count data reaches the gradation data. A voltage pulse having a pulse width equal to the period is output.

  Each output buffer amplifier 26 selects and outputs positive element voltages V1, V2, V3, and V4 supplied from the outside based on the upper 2 bits of the gradation data supplied to the corresponding pulse width modulation circuit 25. . Therefore, the voltage pulse from the pulse width modulation circuit 25 is amplified to a pulse amplitude equal to any one of these element voltages V1, V2, V3, and V4. At this time, the selection element voltage is output from the output buffer amplifier 26 for a period equal to the pulse width of the pulse voltage from the pulse width modulation circuit 25. That is, the output buffer amplifier 26 outputs a signal line drive signal having a pulse amplitude and a pulse width depending on the gradation value of the gradation data.

FIG. 9 is a graph showing an example of the signal waveform of the signal line drive signal.
The signal line drive signal is divided into four areas (A) to (D) according to the magnitude of the video signal, and has different amplitude values V1 to V4 for each area. The amplitude values V1 to V4 of the drive signal are increased step by step in each region, and the pulse width is varied in each region in accordance with the value of the video signal, thereby enabling fine gradation expression. Yes.

As shown in FIG. 9A, when the gradation value is 0 to 256, the signal line drive signal is a pulse having a pulse length of the element voltage V1 and a pulse width of 0 to 256.
As shown in FIG. 9B, when the gradation value is 257 to 512, the signal line drive signal includes a pulse having a pulse length of the element voltage V2 and a pulse length of 0 to 256, and a pulse amplitude of This is a combination with the pulse having the remaining time length at the element voltage V1.
As shown in FIG. 9C, when the gradation value is 513 to 768, the signal line drive signal includes a pulse with a pulse amplitude of the element voltage V3 and a pulse length of 0 to 256, and a pulse amplitude of This is a combination with the pulse having the remaining time length at the element voltage V2.
As shown in FIG. 9D, when the gradation value is 769 to 1024, the signal line drive signal includes a pulse with a pulse amplitude of the element voltage V4 and a pulse length of 0 to 256, and a pulse amplitude of This is a combination with the pulse having the remaining time length at the element voltage V3.

  In each electron-emitting device 11, discharge occurs when the device voltage Vf, which is the potential difference between the electrodes composed of the signal line X and the scanning line Y, exceeds the threshold, and the electron beam emitted thereby excites the phosphor 12. . The luminance of each display pixel Px is controlled by the drive current flowing through the electron-emitting device 11 depending on the pulse width and pulse amplitude of the signal line drive signal.

  As described above, according to the display device D of this embodiment, the microcomputer 42 detects the temperature difference between the temperature sensor 16 provided on the face plate FP and the temperature sensor 17 provided on the rear plate RP, and according to the temperature difference. Since the scanning line signal of the scanning line Y is controlled, an image in which the luminance of the display pixel Px becomes dark in the vicinity of the spacer SP arranged at a predetermined interval on the display panel 10 due to the temperature difference between the face plate FP and the rear plate RP. The deterioration phenomenon can be prevented.

(Other embodiments)
Embodiments of the present invention are not limited to the above-described embodiments, and can be expanded and modified. The expanded and modified embodiments are also included in the technical scope of the present invention.

For example, in the above-described embodiment, the scanning line signal supplied to the scanning lines in the vicinity of the spacers SP is caused by the deterioration of the luminance of the surface of the display panel 10 (the deterioration of the video quality) caused by the temperature difference between the face plate FP and the rear plate RP. In addition to the voltage correction (signal control), the voltage correction (signal control) of the signal line drive signal supplied to the signal lines of each color of red (R), green (G), and blue (B) is performed. Also good.
Further, a cooling means (such as a Peltier element, a fan or a heat sink) or an overheating means (such as a heater) for eliminating the temperature difference itself between the face plate FP and the rear plate RP is provided on at least one of the face plate FP and the rear plate RP. Also good.
Further, the temperature may be adjusted by connecting the face plate FP and the rear plate RP with a heat pipe or the like to circulate the mutual heat.

The figure showing the display apparatus which concerns on one Embodiment of this invention. The top view which represents typically the state which looked at the display panel of FIG. 1 from the upper surface. The side view showing the state which looked at the display panel of FIG. 1 from the horizontal direction. The temperature characteristic figure showing the relative relationship between the temperature difference of a face plate and a rear plate, and the position where an electron hits a fluorescent substance. The figure which shows an example of a correction table. The figure which shows the other example of a correction table. The schematic diagram showing an example of the content of the gradation correction table. FIG. 9 is a diagram illustrating what is represented as a gradation correction table in FIG. 8. The figure which shows an example of the signal waveform of a signal line drive signal.

Explanation of symbols

  D ... Display device, 10 ... Display panel, 11 ... Electron emission element (electron source), 12 ... Phosphor, 16, 17 ... Temperature sensor, 20 ... Signal line driver, 21 ... Line memory, 22 ... Line memory, 23 ... Drive signal generation unit, 24 ... counter, 25 ... pulse width modulation circuit, 26 ... output buffer amplifier, 30 ... scan line driver, 31 ... shift register, 32 ... output buffer amplifier, 40 ... video signal processing circuit, 41 ... AD conversion Circuit 42, microcomputer, 43, 43a ... correction table, 44 ... multiplier, 45 ... conversion unit, 46 ... conversion table, 47 ... gradation correction table, 50 ... input circuit, 60 ... timing generation circuit, FP ... face plate , RP ... rear plate, W ... side, SP ... spacer, Px ... display pixel, X (X1-Xn) ... signal line, Y (Y1-Ym) ... scanning line.

Claims (5)

A first substrate, a second substrate disposed opposite to the first substrate and having a plurality of signal lines and scanning lines arranged in a matrix, and the scanning line substantially between the first substrate and the second substrate; A display unit comprising spacers arranged in parallel;
Temperature difference detecting means for detecting a temperature difference between the first substrate and the second substrate;
The display unit is configured to supply a scanning line signal to a first scanning line arranged in the vicinity of the spacer and a second scanning line arranged with the first scanning line separated from the spacer among the plurality of scanning lines. A scanning line driving unit to be displayed;
Temperature difference correction information storage means storing correction information for varying a scanning line signal supplied to the first scanning line in accordance with a temperature difference between the first substrate and the second substrate;
A scanning line signal is supplied to the first scanning line based on correction information stored in the temperature difference correction information storage unit according to a temperature difference between the first substrate and the second substrate detected by the temperature difference detection unit. And a control unit for controlling the scanning line driving unit. In the temperature difference correction information storage means,
Correction information for varying the scanning line signal of the first scanning line in a direction to increase the potential difference with the driving signal applied to the signal line as the temperature difference increases is stored in the scanning line driving unit. The display device according to claim 1, wherein the display device is a display device. A first substrate, a second substrate disposed opposite to the first substrate and having a plurality of signal lines and scanning lines arranged in a matrix, and the scanning line substantially between the first substrate and the second substrate; A display unit comprising spacers arranged in parallel;
Temperature difference detecting means for detecting a temperature difference between the first substrate and the second substrate;
The display unit is configured to supply a scanning line signal to a first scanning line arranged in the vicinity of the spacer and a second scanning line arranged with the first scanning line separated from the spacer among the plurality of scanning lines. A scanning line driving unit to be displayed;
The scanning line driving unit is controlled so as to vary the voltage of the scanning line signal supplied to the first scanning line according to the temperature difference between the first substrate and the second substrate detected by the temperature difference detecting means. And a control unit. The controller is
When the temperature difference between the first substrate and the second substrate exceeds a preset allowable range, the scanning line driving unit is configured to vary the voltage of the scanning line signal supplied to the first scanning line. The display device according to claim 3, wherein the display device is controlled. The controller is
The scanning line driving unit is configured to vary the scanning line signal of the first scanning line in a direction in which a potential difference with a driving signal applied to the signal line is increased as a temperature difference is increased. Item 4. The display device according to Item 3.

Images