JP2003099003A - Picture display device, and method for controlling picture display and picture display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a picture display device having high reproducibility and a control method therefor by correcting irregularity of chromaticity of light emitting elements and uniformalizing a color tone of each pixel. SOLUTION: The picture display device comprises a display part 10 in which light emitting elements of a plurality of color tones are arranged for each pixel, a driving part 50 for supplying a driving current to each light emitting element of a plurality of color tones for each pixel based on the picture data concerning a plurality of the color tones, and a chromaticity correction part 11 for distributing a predetermined part of the driving current supplied to a light emitting element corresponding to at least any one of the color tones of each pixel from the driving part 50 to a light emitting element corresponding to the other one or more color tones of the pixel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device in which light emitting elements of a plurality of color tones are arranged for each pixel and a control method thereof, and more specifically, the light emission amount is corrected according to the characteristic variation of the light emitting elements. The present invention relates to an image display device having a function and a control method thereof.

[0002]

2. Description of the Related Art Today, light emitting diodes (Light Emitting)
Diode, hereinafter also referred to as “LED”. ) And other high-luminance light-emitting elements have been developed for each of the three primary colors of light, red (Red), green (Green), and blue (Blue) RGB, so that a large self-luminous full-color display can be created. became. Among them, the LED display has features such as light weight, thinness, and low power consumption, so that the demand as a large display that can be used outdoors is rapidly increasing.

In the case of a large-sized LED display installed outdoors, it is generally constructed by combining a plurality of LED units, and each LED unit displays each part of the full-screen data. In the LED unit, a set of RGB light-emitting diodes is arranged on a substrate in a pixel matrix, and each LED unit performs the same operation as the above-described LED display.
For large large LED displays, for example,
A total of about 300,000 pixels of LEDs of 300 vertical by 640 horizontal are used. Further, in a full-color LED display, this one pixel is composed of a combination of LEDs of 3 dots or more which emit R, G and B respectively.

A dynamic drive system is generally used as a drive system for the LED unit. For example, m
In the case of an LED display configured in a matrix of rows × n columns, the anode terminals of the LEDs located in each row are 1
Commonly connected to one common source line, the cathode terminals of the LEDs located in each column are commonly connected to one current line. The m common source lines are sequentially turned on at a predetermined cycle, and a drive current is supplied to n current lines according to the image data corresponding to the turned on lines. As a result, a drive current corresponding to the image data is applied to the LED of each pixel, and an image is displayed.

In order for the image data to be accurately reproduced on the LED display, the light output characteristics (driving current-luminance characteristics, etc.) of the individual LEDs must be uniform. However, not all LED devices actually manufactured are homogeneous. The LED element is formed on a wafer by a semiconductor manufacturing technique, but the light output characteristics and the emission spectrum vary depending on the manufacturing lot, the wafer, or the chip. Therefore, variations in the LED characteristics of each pixel,
For example, it is necessary to correct the magnitude of the drive current corresponding to each image data according to the variation in brightness and chromaticity.

As a means for correcting image data, for example, a method for correcting brightness has been developed (Japanese Patent Publication No. 2950).
No. 178). For example, a method of correcting so that the same light output can be obtained with respect to the image data input having the same value in any of the LEDs by increasing or decreasing the driving current in an amount corresponding to the variation in the light output characteristic of each LED. There is.

Alternatively, a high quality image is displayed by using the image data whose brightness is corrected for each LED element. Specifically, the brightness correction data corresponding to each LED element is stored in the correction data storage unit in the control circuit that controls the lighting of the LED display. For example, a ROM is used as the correction data storage unit. The control circuit
The image data is corrected and displayed based on the correction data stored in the ROM.

[0008]

However, in any of the above methods, although the luminance can be corrected, the chromaticity cannot be corrected. In the LED element, not only the luminance but also the chromaticity variation exists for each element. Therefore, even if only the brightness correction is performed to make the brightness between pixels uniform, it is not possible to correct the chromaticity of each pixel, and the displayed image becomes rough because the color tone varies. There was a problem that the quality of the. In particular, the greater the number of colors used, the more remarkable the variation in chromaticity. In order to display a high-quality image on a full-color display using RGB, not only luminance correction but also chromaticity correction is important.

The present invention has been made in view of such problems. An important object of the present invention is to provide an image display device that uses light emitting elements in which variations in characteristics are observed. Even if an image display apparatus uses light emitting elements of each color, chromaticity correction is performed to obtain uniform, high-quality reproducibility. An object is to provide an image display device capable of displaying an image and a control method thereof.

[0010]

In order to achieve the above object, the image display device according to claim 1 of the present invention comprises:
A first current for adjusting a driving current supplied to each of the light emitting elements of a plurality of colors for each pixel based on image data regarding the plurality of colors, in which light emitting elements of a plurality of colors are arranged for each pixel. Adjusting unit 61 _R , 61 _G , 61
_B and at least one of the plurality of color tones of each pixel
A second current adjusting unit 65 for adjusting a correction current supplied to a light emitting element corresponding to one or more other color tones of the pixel in order to correct the color tone of the light emitting element corresponding to one color tone; Equipped with. This image display device divides one image frame having VSYNC as a frame signal into a plurality of image transfer frames, and at least one of the image transfer operations is performed based on the same image data in each image transfer frame. In the image transfer frame, a correction current for correcting the color tone of the light emitting element of any one color tone is supplied to the light emitting element of any one other color tone, and at the same time, the correction current of any one light emitting element is changed for each image transfer frame. The present invention is characterized in that the correction current supplied to any one other light emitting element for correcting the color tone is switched to realize the color tone correction for the light emitting elements of a plurality of color tones in a time division manner.

With such a configuration, it is possible to provide an image display device which can make the chromaticity uniform for each pixel regardless of the chromaticity variation of the light emitting element.

With this configuration, the emission chromaticity of the color tone is corrected during the light emission of the light emitting element corresponding to at least one of the plurality of color tones.
By causing a light emitting element corresponding to one or more other color tones to emit light, the chromaticity can be corrected and the display flickering can be prevented.

An image display device according to a second aspect of the present invention has the features of the first aspect,
The color tone of the light emitting element is red, green, or blue.

An image display device according to a third aspect of the present invention is characterized in that the brightness of each light emitting element is corrected.

Further, in the image display device according to the fourth aspect of the present invention, the first current adjusting section 61 includes one first
The current adjusting unit 61 supplies a drive current to the light emitting element of one color tone, and the second current adjusting unit 65 of the second current adjusting unit 65 applies the correction current to the light emitting elements of a plurality of color tones. It is characterized by supplying.

Next, in the image display device according to a fifth aspect of the present invention, the number of image transfer frames obtained by dividing the image frame and the correction current for the light emitting element of any color tone in any of the image transfer frames are corrected. It is characterized in that it can be set whether or not to supply.

Further, in the image display device according to claim 6 of the present invention, the first current adjusting section 61 is a first current adjusting DA converter 61A _R , 61A _G , 61A _B , and The second current adjusting unit 65 is a second current adjusting DA converter 65A.

Further, an image according to claim 7 of the present invention
The image display device controls the light emission of each of the light emitting elements.
At least one lighting pulse generation unit that generates a lighting pulse
63 _R, 63_G, 63_BAnd the lighting pulse generator 63
_R, 63_G, 63_BON / OFF is controlled by each
Controlled multiple primary current switches 62_R, 62_G, 62
_BAnd multiple correction current switches for adjusting the correction current.
Switch SW1 to SW6 and the correction current switches SW1 to SW6
With switch control units 66, 66, 66 for N / OFF control
Equipped with. This image display device includes the first current adjusting unit.
61_R, 61_G, 61_BIs the main current switch 62
_R, 62_G, 62_BDrive to each light emitting element via
The second current adjusting unit 65 adjusts the dynamic current, and the second current adjusting unit 65
It is supplied to each light emitting element through the positive current switches SW1 to SW6.
Adjust the correction current, and add the correction current to the drive current
The color tone correction is performed for each light emitting element.

Further, in the image display device according to the eighth aspect of the present invention, the lighting pulse generating sections 63 _R , 63 _G ,
63 _B, based on the gradation reference clock, and controls the lighting section by gradation data pulse width modulation.

Further, in the image display device according to claim 9 of the present invention, the switch control units 66, 66, 66 receive the correction current switch SW1 in response to a chromaticity correction selection signal.
It is characterized by performing ON / OFF control of 6 to 6.

Further, in the image display control method according to a tenth aspect of the present invention, light emitting elements L _R , L _G , and L _B corresponding to a plurality of color tones RGB are arranged for each pixel, and RG
Image data _D R about _B, D G, the light emitting element for each pixel based on _{D B L R, L G,} each of the light emission amount A of _{L B}
By controlling _R , A _G , and A _B , multicolor light emission is performed. According to this image display control method, one image frame having VSYNC as a frame signal is divided into a plurality of image transfer frames, and at least one of the image transfer operations is performed based on the same image data in each image transfer frame. In the image transfer frame of, the light emitting element Li (i = R,
G, B) emits light based on the image data Di, the light-emitting elements Lk (k ≠ i) of one or more other color tones of the pixel emit light with the light emission amount Ak according to the image data Dk, and
The light emitting element Lk is further made to emit light at the light emitting quantity A′k according to the light emitting quantity Ai of the light emitting element Li, the light emitting quantity of the light emitting element Lk is set to Ak + A′k, and the light emitting quantity A ′ for correction is further set.
In order to correct the addition of k in any one image transfer frame by adding k, the light emitting element of any one of the other color tones is caused to emit light with the light emission amount A′k, and any one is added for each image transfer frame. Amount of light emission A'k that causes one of the other light emitting elements to emit light in order to correct the color tone of the other light emitting element.
The color tone correction for the light emitting elements of a plurality of color tones is realized in a time-divisional manner by switching between the two.

Further, according to the control method of the image display device of the eleventh aspect of the present invention, the light emitting elements of a plurality of color tones are arranged for each pixel, and each pixel is based on the image data relating to the plurality of color tones. A first current adjusting unit 61 _R , 61 _G , 61 _B for adjusting a drive current supplied to each of the light emitting elements having a plurality of color tones, and at least one of the plurality of color tones of each pixel. A second current adjusting unit 65 for adjusting a correction current supplied to a light emitting element corresponding to one or more other color tones of the pixel in order to correct the color tone of the light emitting element corresponding to. Correct the brightness and color tone of the image display device. The control method of the image display device is a brightness / color tone calculation for each pixel of the brightness and color tone of the light emitting element corresponding to each color tone of the display device, by the emission intensity detector having a light receiving element corresponding to a plurality of color tones. In the calculation step, the luminance and color tone of each light emitting element calculated for each pixel in the luminance / color tone calculation step are compared with the reference luminance and the reference color tone, and the luminance difference and the color tone difference are calculated. Color tone difference calculation step, and the drive current supplied to the light emitting element corresponding to each color tone, the first current adjustment 61 _R , 61 _G , 61
_{And the} correction current supplied based on the brightness difference and the color difference calculated in the brightness / color difference calculation step is adjusted by the second current adjusting unit 65 and added to the drive current. A correction step for correcting each pixel brightness and color tone to a reference brightness and a reference color tone, and in the correction step, correction data relating to control of a drive current supplied to the light emitting element of each color tone, When a correction data storing step of storing in a display device and one image frame using VSYNC as a frame signal are divided into a plurality of image transfer frames and an image display operation is performed based on the same image data in each image transfer frame. In at least one image transfer frame,
A step of supplying a correction current for performing luminance / color tone correction based on the correction data to a light emitting element corresponding to the one or more other color tones and adding the correction current to the drive current. A correction current for correcting the color tone and the brightness of the light emitting element of one color tone is supplied to the light emitting element of any one other color tone, and the color tone of any one light emitting element is corrected for each image transfer frame. In order to do so, the correction current supplied to any one of the other light emitting elements is switched to perform the color tone correction and the luminance correction for the light emitting elements of a plurality of color tones in a time division manner.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. However, the embodiments described below exemplify an image display device and a control method thereof for embodying the technical idea of the present invention, and the present invention provides an image display device and a control method thereof as follows. Not specified.

Further, in this specification, in order to facilitate understanding of the claims, the numbers corresponding to the members shown in the embodiments are referred to as "claims column" and "to solve the problems". It is added to the members shown in the column of "means". However, the members shown in the claims are not limited to the members of the embodiment.

The image display control method of the present invention will be described below. According to this method, the display unit 10 in which the light emitting elements L _R , L _G , and L _B corresponding to a plurality of color tones RGB are arranged for each pixel,
Multicolor light emission is performed by controlling the light emission amounts A _R , A _G , and A _B of the light emitting elements L _R , L _G , and L _B for each pixel based on the image data D _R , D _G , and D _B regarding RGB. This is an image display control method.

An LED or the like is used as the light emitting element.
In the following example, three light emitting diodes each capable of emitting red, green, and blue RGB are arranged adjacent to each other to form one pixel. L with RGB adjacent to each pixel
The ED can realize full color display. However, the present invention is not limited to this configuration, and two colors can be arranged close to each other, or two or more LEDs can be arranged for each color.

FIG. 1 shows a plurality of color tones R on the display unit 10.
An example of a pixel including light emitting elements L _R , L _G , and L _B corresponding to GB is shown. Here, one pixel is a picture element (dot)
Although an example in which it is configured by three light emitting diodes corresponding to the above is shown, full color display is possible by configuring each RGB by at least one dot. In this example, the anode terminal of each light emitting element is connected in common to one common source line, RGB each of the light emitting elements L _R, L _G, the cathode terminal of the L _B are connected to respective current lines. Light emitting elements L _R , L _G , L _B
The light emission amount of is controlled by the drive current supplied to the current line, for example. In this way, the light emitting elements L _R , L _G ,
The L _B has a display unit 10 disposed for each pixel, the image data D _R, D _G, the amount of current and / or the driving time of the driving current supplied to each based on D _B, amount of light emission A _R, A _G, is a multi-color light emission by controlling the a _B, to realize an image display control.

At this time, the light emission amount A'k of the light emitting element Lk (k ≠ i), which corresponds to the correction amount described later, can be emitted within the same time as the light emitting time of the light emitting element Li. However,
It is not necessary to emit light within the same light emission time as long as there is a time lag within a range in which an afterimage remains in human eyes.

In the present invention, in order to prevent variation in chromaticity of each pixel due to manufacturing variation of each light emitting element, the light emitting element Li (i = R, i = R, G, B) as image data Di
When emitting light based on
The light emitting element Lk (k ≠ i) of one color tone is set to the image data Dk.
In addition to the light emission amount Ak according to the light emission amount Ak, the light emission amount A′k for the light emitting element Lk according to the light emission amount Ai of the light emitting element Li is further emitted, and the light emission amount Ak +
Control is performed to emit light of A'k.

Below, one color tone light emitting element Lk (k ≠
An example of a method of controlling the light emission amount A′k added to the light emission amount Ak emitted by i) according to the image data Dk will be described.

In this example, the light emission amount Ai of the light emitting element Li is
The light emission amount A′k for the corresponding light emitting element Lk is calculated as Ai.
The light emission amount is obtained by multiplying the distribution ratio for each color tone. This
In this case, the distribution ratio is
r_G, R_BThe distribution ratio of B and R to G and
g_B, G_RDistribution ratios of R and G to B and B respectively
b_R, B_GIs expressed as. That is, the image data D
_R, D_G, D_BEach light emitting element L based on_R,
L_G, L_BThe amount of light emitted is A_R, A_G, A_BIf
In the image display control method of the present invention, each light emission
Element L_R, L_G, L_BThe final luminous intensity of A ”_R, A ”_G,
A ”_BIs A_R, A_G, A_BTo A ’_R, A ’_G, A ’ _B
Are controlled so that the light emission amounts are respectively added. Luminous intensity
A ”_R, A ”_G, A ” _BIs represented by the following formula.

[0032]

[Equation 1]

Therefore, in the conventional image display control method, the light emission amount Ai (i = R, B, G) of each light emitting element Li (i = R, B, G) corresponds to the corresponding image data Di (i = Although one output characteristic is shown for R, B, G), in the image display control method of the present invention, the light emission amount A ″ i (i) of each light emitting element Li (i = R, B, G).
= R, B, G) is the corresponding image data Di (i = R,
B, G) does not have one output characteristic, and image data Dk (k ≠ i) of light emitting elements Lk (k ≠ i) of other color tones.
Also depends on the light emission amount Ak (k ≠ i) corresponding to

Next, an example of a method of setting the light emission amount A'k to be added to the light emitting element Lk according to the light emission amount Ai of the light emitting element Li will be described. For example, when a light emitting diode (LED) is used as a light emitting element, the image data Di (i = R, B, G) is used to correct chromaticity variation due to wavelength variation or light output characteristic variation of the LED.
The light emission amounts of the light emitting elements Lk (k ≠ i) of other color tones are set so that the chromaticity of the pixel corresponding to each maximum value becomes the reference chromaticity. Here, as the reference chromaticity, it is preferable to select three chromaticities that can be expressed for all combinations within the range of the production variation of the RGB LEDs.

An example of a specific reference chromaticity selection method will be described with reference to the chromaticity diagram of FIG. On the chromaticity diagram of FIG.
B Each LED has a maximum light emission amount A corresponding to the maximum value Di _Max (i = R, B, G) of the image data of the corresponding color tone.
A region ΔSi (i = R, B, G) showing a range of chromaticity variation when light is emitted at i _Max (i = R, B, G) is drawn. In FIG. 2, each area ΔSi is schematically shown as a polygon. At this time, it can be considered that all the LEDs are distributed within this ΔSi region (regions indicated by diagonal lines in FIG. 2).

The triangles are formed by connecting the vertices of this ΔSi region. From the vertices of the respective ΔSi regions of RGB, the vertices that minimize the area of the triangle formed by the intersections of the vertices are selected. Each vertex S ′ of the smallest triangle ΔS ′ _R S ′ _G S ′ _B formed by the intersections of the selected vertices
_R , S ′ _G , and S ′ _B are selected as the reference chromaticities of RGB. That is, S ′ _R , S ′ _G , and
By selecting S ′ _B , the triangle ΔS ′ _R S ′ _G S ′ _B
All chromaticities in the area can be expressed.

By setting the reference chromaticity of each color in this way, the chromaticity within the range of chromaticity that can be expressed by any combination of LEDs (within the triangle ΔS ′ _R S ′ _G S ′ _B area) Can be expressed. The chromaticity correction can be performed by emitting light of another color tone. As a result, it is possible to significantly reduce the chromaticity display variation between pixels and prevent the chromaticity variation within the same LED unit 1.

In FIG. 2, the range of chromaticity variation is exaggerated for the sake of convenience of explanation, so that the chromaticity range that can be displayed by the display unit 10 seems to be small (the area indicated by the broken line in FIG. 2). From the triangle ΔS ′ _R S ′ _G S ′ _B )), the LED display has the characteristic that the color expression range is sufficiently large even when compared with, for example, a CRT. The chromaticity expression range of the applied display device is still larger than that of the CRT. Further, when the chromaticity is corrected by using the luminescence amount A′k added to LEDs of other color tones as the luminescence amount obtained by multiplying the luminescence amount Ai by the distribution ratio, for example, the chromaticity is continuously corrected within the entire chromaticity range. As a result, the chromaticity variation can be prevented not only in the areas near RGB but also in the entire color range.

Further, here, when each of the RGB light emitting elements Li (i = R, G, B) of each pixel emits light based on the image data Di, the light emitting element Lk (of any other color tone of the pixel). For k ≠ i), the light emission amount Ak + A′k obtained by adding the light emission amount Ak of the light emitting element according to the image data Dk to the light emission amount A′k of the light emitting element Lk according to the light emission amount Ai of the light emitting element Li is calculated. Although the image display control method of controlling to perform is shown as an example, the light emission amount Ak of the light emitting element corresponding to the image data Dk of the light emitting element Lk (k ≠ i) of one or more other color tones of the pixel is set to Li. Light emission amount Ak + obtained by adding the light emission amount A′k to the light emitting element Lk according to the light emission amount Ai of
You may control so that light emission of A'k may be performed.

For example, consider the color discrimination threshold on the chromaticity diagram.
Then, in the R region, the human eye is in the B direction compared to the G direction.
Because it is insensitive to the difference in chromaticity,
Amount of light emitted from R LED only_RA'according to
_GAmount of luminescence added_G+ A ' _GControl so that
May be. At present, gallium nitride compounds
Compared to R and B LEDs, G LEDs made of conductors
Due to the large variation in chromaticity, the R and B LED
If the flicker is small enough,
Light emission amount A'of only R and / or B LEDs_R, A ’_G
Amount of luminescence added_R+ A '_RAnd / or A_G+ A '
_GMay be controlled to emit light. But the human eye
Has a small color discrimination threshold in the B region and is sensitive to the chromaticity difference.
Therefore, even if the chromaticity of the B LED is small,
At the same time, the chromaticity of the B LED is corrected.
May be. Of course, the RGB chromaticity
Whether to omit the correction is not limited to the above example, and any color
Variation in chromaticity of the light-emitting element, and its color
Select appropriately according to the shape of the color discrimination threshold in the degree range
be able to.

Further, image data D _R , D regarding RGB
_G, the light emitting device based on _{D B L R, L G,} light emission _A R of _{L B,} A G, the control of the _{A B} light emitting elements _{L R, L} G,
When the image display is controlled by the amount of drive current supplied to L _B and / or the drive time, the light emitting element Lk
On the other hand, it is preferable to control the light emission amount A′k added according to the light emission amount Ai of the light emitting element Li by increasing the drive current supplied to the light emitting element Lk. This is because, in each pixel, the amount of light emission is simultaneously controlled within the same drive time of each light emitting element, and display flicker can be minimized.

Although an example in which an LED is used as the light emitting element is shown here, the present invention is not limited to the LED as the light emitting element, and is suitable for an image display device in which chromaticity variation occurs between light emitting elements.

Note that there is a correlation between the correction of the luminance variation and the correction of the chromaticity variation, and when considering the correction of the image display device, it is important to perform the luminance variation correction at the same time as the chromaticity variation correction. is there.

As the light emitting diode, a semiconductor light emitting element capable of various light emission can be used. As semiconductor elements, GaP, GaAs, GaN, InN, AlN, GaAsP, GaAlAs, InG
Examples include semiconductors such as aN, AlGaN, AlGaInP, and InGaAlN used for the light emitting layer. Also, the semiconductor structure is MI
Examples thereof include a homo structure, a hetero structure, or a double hetero structure having an S junction, a PIN junction, or a PN junction.

The emission wavelength of the semiconductor light emitting device can be variously selected from ultraviolet light to infrared light depending on the material of the semiconductor layer and the mixed crystallinity thereof. Further, in order to have a quantum effect, a single quantum well structure or a multiple quantum well structure in which the light emitting layer is a thin film can be used.

Not only the three primary colors of RGB but also a light emitting diode which is a combination of light from an LED chip and a fluorescent substance which is excited by the light and emits light can be used. In this case, by using a fluorescent substance that is excited by light from the light emitting diode and converted into a long wavelength, a light emitting diode capable of emitting white light with good linearity can be obtained by using one type of light emitting element.

Further, the light emitting diode may have various shapes. Specifically, the LED chip, which is a light emitting element, is electrically connected to the lead terminal, and a bullet type covered with a mold resin or the like, a chip type LED, or the light emitting element itself is used.

[0048]

EXAMPLES A concrete configuration example of the embodiment of the present invention will be described below.

[Embodiment 1] FIG. 3 shows a schematic block diagram of an example of an image display device according to the present invention. The image display device shown in this figure shows an example in which one image is divided into a plurality of image regions and applied to an LED unit for displaying. The image display device shown in FIG. 3 includes a display unit 10, a correction data storage unit 32, a correction data control unit 31 connected to the correction data storage unit 32, and a communication unit 33 connected to the correction data control unit 31. , The current supply unit 14 connected to the correction data control unit 31, the brightness correction unit 13, and the chromaticity correction unit 1
1, an image input unit 19 that receives image data input from the outside, a drive time control unit 12 that receives image data from the image input unit 19, an address generation unit 18, and a common driver 17.

The image display device of the present invention can display a moving image or a still image by displaying a screen of 30 frames or more as an image frame in one second, for example. Generally, an image display device using a light emitting element has a higher refresh rate than an image display using a cathode ray tube, and increases the number of image frame displays per second. In FIG. 3, reference numeral 10 denotes a display unit 10 that displays an image corresponding to a designated image area among the divided image areas. The display unit 10 displays, for example, RGs corresponding to three color tones.
One pixel is formed by combining the respective LEDs of B, and a plurality of pixels are arranged in a matrix of m rows × n columns.

The correction data storage unit 32 stores correction data necessary for correcting the luminance and chromaticity of the display unit 10. A storage element such as a RAM, a flash memory, or an EEPROM is used as the correction data storage unit 32. The correction data storage unit 32 stores various correction data necessary for image correction. For example, in order to correct the brightness for each dot in the brightness correction unit 13, the white balance correction data and the surface brightness correction data which are the data necessary for controlling the predetermined current amount supplied for each color tone in the current supply unit 14. Pixel luminance correction data necessary for the chromaticity correction unit 11 and the driving current supplied to the light emitting element corresponding to one color tone, which is necessary for correcting the chromaticity for each pixel in the chromaticity correction unit 11, one or more other than Chromaticity correction data and the like regarding a predetermined part of the drive current to be distributed to the light emitting elements corresponding to the color tone are stored in the correction data storage unit 32.

The correction data control unit 31 calls various kinds of correction data stored in the correction data storage unit 32 and writes them into the current supply unit 14, the brightness correction unit 13 and the chromaticity correction unit 11, respectively.

Image data input from the outside is input to the drive time control unit 12 via the image input unit 19. The drive time control unit 12 includes a current supply unit 14 and a brightness correction unit 1.
The current of the current amount corrected by 3 is supplied, the drive time is controlled by the pulse width of the supplied drive current based on the image data, and the chromaticity correction unit 11 is used as the pulse drive current.
To enter. At this time, the driving time control unit 12 may control the chromaticity correction unit 11 not by the pulse width but by the number of times of driving a constant pulse.

The chromaticity correction unit 11 further corrects the pulse drive current input from the drive time control unit 12. The chromaticity correction unit 11 corrects the pulse drive current supplied to each LED based on the chromaticity correction data in order to correct the chromaticity difference due to the chromaticity variation of each LED.

The address generator 18 generates an address indicating a row corresponding to the input synchronization signal Hs and inputs it to the common driver 17, the correction data controller 31 and the drive time controller 12. The common driver 17 drives the row corresponding to the input address. The chromaticity correction unit 11 also serves as a segment driver, and the drive time control unit 12
To drive a column corresponding to, and drive one pixel in time division together with the common driver 17 to realize matrix display.

Next, the brightness correction and chromaticity correction of the display section 10 will be described. In the current supply unit 14, the current supply unit 14 is based on the white balance correction data and the surface brightness correction data stored in the correction data storage unit 32.
The drive current supplied from the to the brightness correction unit 13 is corrected for each RGB. In this way, the white balance and surface brightness of the entire LED unit 1 are corrected, and variations among the LED units 1 are prevented.

In the brightness correction unit 13, the drive current supplied to each LED is corrected for each RGB of each pixel based on the pixel brightness correction data stored in the correction data storage unit 32 for each RGB of each pixel. . In this way, the brightness of each pixel is adjusted, and variations in brightness of each pixel in the same LED unit 1 are prevented.

In the chromaticity correction unit 11, the pulse drive current supplied from the drive time control unit 12 is the RGB of each pixel based on the chromaticity correction data stored in the correction data storage unit 32 for each RGB of each pixel. It is corrected every time. In this way, the chromaticity of each pixel is corrected, and the RG of each LED unit is corrected.
Each color tone of B is adjusted to the reference value, and the variation in chromaticity of each pixel in the LED unit 1 is significantly reduced.

Therefore, according to the present invention, not only the variations in luminance and chromaticity of each LED unit but also the same L
It is possible to prevent variations in luminance and chromaticity of each pixel in the ED unit.

The current supply unit 14 first corrects the drive currents supplied to the LEDs corresponding to the color tones of RGB based on the white balance correction data and the surface brightness correction data, and then the brightness correction unit. 13 and the chromaticity correction unit 11 individually correct the drive current for each pixel, thereby performing white balance correction,
It becomes possible to perform correction for each element such as surface brightness correction, pixel brightness correction, and pixel chromaticity correction.

Next, the chromaticity correction unit 11 will be described. In the chromaticity correction unit 11, a predetermined part of the drive current supplied to the LEDs of the respective color tones is distributed to the drive currents of other tones based on the chromaticity correction data stored in advance for each pixel. It That is, the LEDs of G and B that form the pixels having the same drive current for R and the LEDs of B and R that form the pixels of the same drive current for G form the pixels of R and G that form the same drive current for B. It is distributed to each LED. The predetermined part of the drive current to be distributed is
For example, it is determined by setting the distribution ratio as the chromaticity correction data. The chromaticity correction data is set so that the chromaticity when one color LED of each pixel is driven by a predetermined pulse drive current corresponds to the other chromaticity LE.
The distribution ratio of the pulse drive current to D is set in advance and stored in the storage unit for each color tone of each pixel.

[0062] Here, and G, the distribution ratio of B respectively _r G, and _{r B} for R, _g B B for G, the distribution ratio R respectively, and _{g R,} R for B, the distribution ratio of G respectively _Let b _R and b _G. The image data D _R , D _G , D
Emitting element _L R based on _{B, L G,} L _B, respectively the amount of charge supplied to the _{Q R, Q G,} and _{Q B.} Furthermore, the amount of charge applied depending on the amount of light emission of the other light-emitting elements each Q _'R, Q' _G, when the Q _'B, are respectively supplied emitting elements L _R of a certain _pixel, L _G, the L _B The total amount of charges Q ″ _R , Q ″ _G , Q ″ _B is expressed by the following equation.

[0063]

[Equation 2]

The amount of light emitted from the light emitting element can be controlled by controlling the amount of charge described above. Here, the light emitting elements L _R and L of a certain pixel, which are supplied from the current supply unit 14.
_The driving current amounts for _G and L _B are I _R , I _G , and I, respectively.
Is _B, and the image data _{D R, D G,} the drive time _T of performing gradation representation based on _{D B R,} T _G, when controlling as _{T B,} the charge amount _{Q R, Q G, Q B} and Q _'R,
Q _'G, Q' _B is represented by the following equation.

[0065]

## EQU00003 ## Qi = IiTi (i = R, G, B), Q'i = .SIGMA. _(K ≠ _i) i _k IkTk (i _k = r _G ,
r _B , g _B , g _R , b _R , b _G )

This situation will be described with reference to FIG. For example, image data D _R , D _G , D of each pixel
_The RGB pulse drive currents supplied from the drive time control unit 12 based on _B are shown in FIG.
When represented by (b) and (c), the final pulse drive currents corrected by the chromaticity correction unit 11 and supplied to the respective RGB LEDs of the pixel are (d), (e), ( It can be represented by f). At this time, the charge amounts Q ″ _R , Q ″ _G , Q ″ supplied to the respective RGB LEDs of the pixel.
_B is represented by the area surrounded by the solid line. That is, in this example, for example, the light emission of the light emitting element L _B corresponding to the color tone of B is not limited to the driving time T _B based on the image data D _B , but also the light emitting element L of another color tone based on the image data D _R and D _{G. R, L G} of the drive time _T R, will be also performed in the _{T G.} That is, the charge amount Q ″ i finally supplied.
Is the original charge amount Qi plus the charge amount Q′i corresponding to the portion surrounded by the diagonal lines in FIG.

In the above example, the amount of distributed charge Q'k
An example is shown in which (k ≠ i) is added during the driving time Ti based on the image data Di of another color tone. However, the present invention may add the distributed charge amount Q′k to a time shorter than the drive time Ti based on the image data Di. This is because the charge amount to be distributed is not larger than the basic charge amount, and in order to perform the distributed charge amount Q′k during the drive time Ti based on the image data Di, the drive current amount k to be distributed. _This is because it is necessary to control _i Ii with high accuracy.

FIG. 5 shows a schematic diagram of the chromaticity correction unit 11.
In the chromaticity correction unit 11, RGB distribution blocks 111a, 111b, 111c and composite blocks 112a, 112b, 112c are provided.
Are arranged. Each of the distribution blocks 111a, 111b, 111c has a chromaticity correction data storage unit that stores a distribution ratio, and is supplied from the drive time control unit 12 corresponding to RGB based on the stored chromaticity correction data. The pulse drive current is distributed to each synthesis block 112a, 112b, 112c. And RG
In each of B composite blocks 112a, 112b, 112c,
The pulse drive currents distributed from the distribution blocks 111a, 111b, 111c are combined with the original pulse drive currents, and the combined pulse drive currents are supplied to the light emitting elements to be driven. The chromaticity correction data storage unit may be configured to store the distribution ratio for all pixels, but
It is preferable to reduce the memory capacity by dynamically rewriting the data of the distribution ratio storage memory for each pixel or each row as the memory capacity for each pixel or one row. In order to realize this configuration, for example, the chromaticity correction unit 1
The No. 1 chromaticity correction data storage unit is a chromaticity correction data temporary storage unit, and is configured by a register, a RAM, and the like.

FIG. 6 shows an example in which the chromaticity correction data storage unit is composed of one shift register corresponding to the capacity of one row and a register of the capacity of one row. FIG. 6 shows only the part relating to R, and this figure is a schematic diagram showing the R distribution block 111a and the R synthesis block 112a. The registers in the R distribution block 111a hold the chromaticity correction data r _G and r _B for the drive target row. The distribution circuit, based on the chromaticity correction data r _G , r _B held in the register, LE of G and B.
The pulse drive current to be distributed to D is distributed to the G and B composite blocks 112b and 112c (not shown in FIG. 6). R
Similarly, the combining block 112a adds the pulse driving currents distributed from the G and B distribution blocks 111b and c to the R LEDs to the original pulse driving current supplied from the driving time control unit 12 and combines them. , To the R LED, which is the pixel to be driven.

The chromaticity correction data of the next row is input to the shift register via the chromaticity correction data line DATA for each r _G and r _B while being sequentially shifted by the clock signal CLK. Then, the chromaticity correction data is transferred to the register by the latch signal LATCH according to the switching timing to the next row, and the chromaticity correction data of the next drive target row is held in the register. In this way, by inputting the chromaticity correction data while sequentially shifting by the shift register, the circuit configuration can be simplified. Here chromaticity correction data r _G, an example that is input in parallel for each r _B, may be constituted by connecting the chromaticity correcting data r _G, the shift register corresponding to r _B in series .

[Second Embodiment] Next, a second embodiment which is another embodiment of the present invention will be described.

FIG. 7 shows the light emitting element L _{R in the} second embodiment.
The pulse drive current for one image frame time supplied to each of L _G and L _B is shown. In this specification, an image frame refers to a section in which one screen of image data is displayed, and
In the chart shown in the uppermost row of FIG.
The interval between SYNC (vertical synchronization signal) pulses corresponds to one image frame time. Here, an image frame time corresponding to one image frame of a video signal corresponding to one color tone is divided, and a drive pulse whose pulse width is controlled corresponding to the image data is assigned to each. The amount of light emission is controlled by setting a part of the divided image frame time as a predetermined time and supplying a part of the pulse drive current to the light emitting element of another color tone. Here, for the sake of simplification of the drawing, the width of each area surrounded by a line is defined as the image data D _R , D _G , D of the corresponding image frame.
Drive time _T R based on _B, and that T G, the _{T B} is set. Further, the drive time control unit 12 uses a high frequency reference clock so that gradation expression can be performed in the divided image frame time.

As an example, the pulse drive current of the light emitting element L _R corresponding to _R will be described. A part of the image frame time obtained by dividing one image frame is used as the light emitting elements L _G and L _B.
And the pulse drive currents respectively supplied to the above. In FIG. 7, the pulses at the end of the image frame time are interchanged with each other. As a result, the light emission amount A ′ _R corresponding to the light emission amounts A _G and A _B with respect to the light emitting devices L _G and L _B of another color tone is changed to the light emission amount A of the light emitting device corresponding to R within the driving time of one image frame. Can be added to _R. At this time, it is possible to add the light emission amount according to the color tone variation of each light emitting element by controlling the number of pulse drive currents to be exchanged or by controlling the drive current amount.

Also in the second embodiment, as in the first embodiment, the number of pulse driving currents to be replaced, which is the chromaticity correction data, or the driving current amount is stored in the chromaticity correction data storage section of each distribution block 111a, 111b, 111c. The data is stored, the distribution circuit generates a pulse drive current according to the chromaticity correction data, and appropriately supplies the pulse drive current to each of the synthesis blocks 112a, 112b, 112c.

[Third Embodiment] A third embodiment, which is still another embodiment, will be described.

FIG. 8 shows a light emitting device L according to the third embodiment._R,
L_G, L_BExamples of pulse drive currents supplied to each
Show. Here, one screen of video signal corresponding to one color tone
The drive time corresponding to the image frame is divided into three.
With one of the divided times as the main display period, the light emitting element
The pulse drive current of the color corresponding to
The two driving times are set as the color correction period, and the
The amount of light emission A "k added by supplying a drive current
To control. Here each of the
The area is the image data of the corresponding image frame.
D_R, D_G, D _BDrive time T based on_R, T_G, T_BBut
It is assumed to be set. In this example, the light emitting element
L_R, L_G, L_BImage data corresponding to
D_R, D_G, D_BFor pulse drive current based on
Drive time can be increased by setting a larger reference clock width
The pulse drive current for other colors.
By setting the quasi-clock width small, the drive time
Shorten. In this way, when driving one image frame
Light emission from one color tone light emitting element according to the amount of light emitted
The amount of light can be added to the amount of light emitted by light emitting devices of other colors.
Wear. At this time, the reference clock width, that is, the reference clock
Control the frequency ratio of, or control the amount of drive current
Therefore, the amount of light emitted can be adjusted according to the variation of each light emitting element.
Can be obtained.

In the third embodiment, the drive time control section 12 has a chromaticity correction data storage section, and controls each drive time based on the data relating to the frequency ratio of the reference clock which is the chromaticity correction data. Then, in the chromaticity correction unit 11,
The pulse driving currents are switched to the light emitting elements to be supplied according to the switching timing of the pulse driving currents.

Although the above-described Examples 1 to 3 have been described so as to perform the chromaticity correction on any of the R, G, and B light emitting elements, the chromaticity correction unit may use at least one of a plurality of color tones as necessary. A predetermined part of the drive current supplied to the light emitting element corresponding to the color tone may be distributed to the light emitting elements corresponding to one or more other color tones.

The example in which the correction data storage unit 32 is configured in the LED unit and the chromaticity correction unit 11 is directly controlled based on the chromaticity correction data stored in the correction data storage unit 32 has been described above. However, the image display control method of the present invention can reflect the brightness and color tone variation information of the light emitting element corresponding to the display data by making the display data multi-bit by using the image signal processing method. . However, in this case, signal processing becomes complicated, and it is difficult to achieve both high-resolution gradation control and highly accurate luminance correction and chromaticity correction. Further, in the case of a large display such as an LED display which is divided into small units, since the correction data is placed in the signal processing portion that collectively controls the display data, the light emitting element and the variation data of the light emitting element are separated. Therefore, it becomes difficult to manage the data during maintenance and inspection such as when replacing some units. Therefore, a direct control method is preferable as the image display control method for the LED unit.

[Chromaticity Correction Method of Image Display Device] Next, as a fourth embodiment, a control method of the image display device of the present invention will be described. FIG. 9 is a conceptual diagram of a chromaticity correction system used in the control method of the image display device of the present invention. The system shown in this figure includes an LED unit 1, a brightness / chromaticity correction device 41 connected to the LED unit 1, and a brightness / chromaticity detection device 41 connected to the brightness / chromaticity correction device 41 to detect the emission intensity of the LED unit 1. It is composed of a chromaticity meter 42.

The chromaticity correction system controls the lighting of each dot of the LED unit 1 by the brightness / chromaticity correction device 41. A light emission intensity detector having light receiving elements corresponding to a plurality of color tones is arranged and connected so that the light emission from the LED unit 1 as the luminance / chromaticity meter 42 is received by the light receiving portion of the light emission intensity detector. The luminance / chromaticity correction device 41 reads the chromaticity and luminance data of each pixel of the LED unit 1 by the luminance / chromaticity meter 42 and calculates the average value of each of the LED units 1 as a whole. Then, the drive currents supplied from the current supply unit 14 are corrected for each RGB so that the respective average values thereof match the preset reference values of the white balance and the surface brightness. RGB of each pixel
The correction value for each is obtained by matrix calculation from reference values of luminance and chromaticity. Further, the dot correction value and the chromaticity correction value are also obtained at the same time. The correction data relating to this control is stored in the correction data storage unit 32 as white balance correction data and surface brightness correction data via the communication unit 33 in the LED unit 1 shown in FIG.

Next, the luminance / chromaticity correction device 41 drives the L driven according to the driving current condition corrected by the set value.
The brightness data of each dot of the ED unit 1 is read.
Then, the brightness correction unit 13 in FIG. 3 controls the drive current for each dot so that the brightness of each dot matches the preset reference value. The pixel brightness correction data regarding this control is stored as pixel brightness correction data in the correction data storage unit 32 via the communication unit 33 in the LED unit 1.

Further, in each pixel of the LED unit 1, the LED corresponding to each color tone RGB is set to the RGB of each pixel.
The chromaticity correction unit 11 uses the pulse driving current corrected for each
Drive without distribution at. Then, each chromaticity is calculated for each pixel from the received light intensity of the light receiving element corresponding to a plurality of color tones. Further, the chromaticity calculated for each pixel by the light emitting element of each color tone is compared with the reference chromaticity.
Based on the chromaticity difference between the chromaticity calculated for each pixel and the reference chromaticity, the luminance / chromaticity correction device 41 controls the pulse drive current distributed by the chromaticity correction unit 11 of the LED unit 1 to The chromaticity of each pixel is corrected by the light emitting element having the color tone of. The luminance / chromaticity correction device 41 provides, for each pixel, chromaticity correction data relating to the drive current distributed from the drive current supplied to the LED of each color tone to the LEDs of other color tones.
The chromaticity correction data for each pixel is stored in the correction data storage unit 32 via the communication unit 33 in the LED unit 1.
The luminance correction value and the chromaticity correction value may be obtained at the same time by obtaining a correction value for each RGB of each pixel by matrix calculation from the reference values of the luminance and the chromaticity.

The above correction method is an example for explaining the present system, and by repeating this process a plurality of times,
It goes without saying that the convergence value of correction can be made more accurate. Even if the correction process is started from chromaticity correction and pixel brightness correction, surface brightness correction, and white balance adjustment are performed in the reverse order, the effective effect can be obtained. Further, in the present invention, the method of separately storing various correction data such as chromaticity correction data, pixel correction data, surface luminance correction data, and white balance correction data has been described.
It is also possible to collectively process each pixel and store it as correction data for each pixel.

[Fifth Embodiment] An image display apparatus according to a fifth embodiment of the present invention will be described. In this embodiment, a main current is supplied to an LED forming an arbitrary pixel to control the brightness, and a correction current for chromaticity correction is added to an LED forming another pixel to also perform chromaticity correction. It is something to do.

That is, in the structure in which the light emitting elements of three colors are connected to the drive circuit, in order to correct the variation in the color tone, that is, the chromaticity of the light emitting elements of each color, the present invention selects the light emitting element of the color to be chromaticity corrected. On the other hand, chromaticity correction is performed by slightly turning on the other two color light emitting elements. For example, when correcting the chromaticity of red, the chromaticity of the red light emitting element is corrected by adding a correction current to the green and / or blue light emitting element. Similarly, red and blue correction currents are added for green chromaticity correction, and red and blue for blue chromaticity correction.
The green correction current is added in a time-sharing manner.

FIG. 10 is a block diagram conceptually showing the structure of the LED display unit according to the image display apparatus of the fifth embodiment. The image display device of FIG. 10 has a plurality of LEDs.
A display unit 10 in which pixels are arranged in a matrix for each pixel L,
A drive unit 50 that drives the LEDs of the display unit 10, and a drive unit 5
A drive control unit 51 for transmitting various control data to 0 is provided. The drive unit 50 includes a vertical drive unit 50A and a horizontal drive unit 5A.
It consists of 0B. The vertical driver 50A is the common driver 17
The horizontal drive unit 50B is the LED driver 50b.

In the image display device of FIG. 10, the drive control unit 5
1 transmits image data, luminance correction data, chromaticity correction data, etc. to the drive unit 50. In this image display device, dynamic drive is directly performed. The drive control unit 51 controls the common driver 17 that is the vertical drive unit 50A, and the common driver 17 switches the power supply to the LEDs connected to each common line on the LED dot matrix that is the display unit 10.

LED driver 5 which is the horizontal drive section 50B
0b is connected to a plurality of stages and supplies a current to the LED connected to the row selected by the common driver 17.

FIG. 11 shows an example of the circuit configuration of the image display device of the fifth embodiment. The horizontal driving unit shown in the figure includes L _R , L _G , and L _B as LEDs that are light emitting elements, and LEDs of these.
Connected to each of the three first current drive units 52 that can be individually driven and controlled, and a second current drive unit 52 that supplies a correction current to each LED.
Current drive section 53, first current drive section 52 and second current drive section 53
Connected to the current driver 53 of and inputting a lighting pulse 3
One lighting pulse generator 63 _R , 63 _G , 63 _B is provided. The lighting pulse generator 63 of each LED is connected to the second current driver 53 via the selector 54. The selector 54 is a selector that selects the input from each lighting pulse generation unit 63 and outputs it to the second current drive unit 53, and the correction current of each LED is time-divided by one second current drive unit 53. Can be controlled. The circuit having this configuration is configured such that the first current driver 52
Corrects the brightness of each LED based on the lighting pulse, and the second current driver 53 supplies a correction current based on the lighting pulse selected by the selector 54 to correct the chromaticity of each LED.

[Sixth Embodiment] FIG. 12 shows a structural example of an image display device according to a sixth embodiment of the present invention. The first current driver 52 shown in this figure is connected to each light emitting element to supply a main current based on image data, and a plurality of first constant currents that can be individually driven and controlled for each light emitting element. The driving unit 60 and the first constant current driving unit 60 are connected to the first
The first current adjusting unit 61 that adjusts the output current of the constant current driving unit 60, and the main current control unit 61 that is connected in series between the first constant current driving unit 60 and the light emitting element to control the current supply to the light emitting element. A current switch 62 is provided.

The first constant current drive section 60 shown in FIG.
They are connected to the respective LEDs via main current switches 62 _R , 62 _G and 62 _B , respectively. Each main current switch 6
The ON / OFF control of No. 2 is performed by the lighting pulse generators 63 _R , 63 _G , 6 connected to the respective main current switches 62.
_3B . The lighting pulse generation unit 63 generates a lighting pulse by pulse width modulation based on the display data received from the drive control unit 51. The lighting pulse generation unit 63 applies the lighting pulse as an ON / OFF control signal for each main current switch 62 to control the drive of the main current in each first constant current drive unit 60.

The main current switch 62 shown in FIG.
Is connected in series between the first constant current drive unit 60 and the light emitting element, but the position of the main current switch 62 is not limited to this. For example, the main current switch 62 may be provided between the first constant current drive unit 60 and the first current adjustment unit 61. The PWM control based on the lighting pulse from the lighting pulse generation unit 63 is not limited to the configuration performed by the main current switch 62, and may be performed by the first constant current drive unit 60 or the first current adjustment unit 61.

In addition, the drive circuit of FIG. 12 further includes a second constant current drive section 64 and a second current adjustment section connected to the second constant current drive section 64 in order to correct the chromaticity of each LED. 6
It is equipped with 5. With this configuration, the main current for controlling the brightness of each LED is subjected to constant current driving by the first constant current driving unit 60, and the second current is further applied to the LED.
LEDs other than the chromaticity to be corrected by the constant current driving unit 64 of
A correction current is added to the chromaticity correction. A second current adjusting unit 65 separately provided for the second constant current driving unit 64.
Adjusts the value of the correction current to be added.

The first current adjusting section 61 and the second current adjusting section 65 are composed of DA converters for current adjustment. That is, in the example of FIG. 12, one circuit for each pixel includes a luminance correction D / A converter (DAC) and a chromaticity correction D / A converter, and each color can be individually controlled.

The second current driver 53 may be separately provided for each of the RGB colors so that the chromaticity of each color can be corrected at the same time. Further, the second current driver 53 is commonly used for RGB and the color of each color is adjusted. The degree correction can also be performed in a time-sharing manner.
In the example of FIG. 12, one second current adjusting unit 65 is connected in parallel to the three second constant current driving units 64. As a result, the second current adjusting unit 6 necessary for supplying the correction current
The number of 5 can be reduced. However, a plurality of constant current circuits necessary for supplying the correction current are provided, such as a configuration in which each second constant current drive unit is provided with a second current adjustment unit,
It is also possible to supply a plurality of chromaticity correction currents at the same time.

The second current adjusting section 65 determines the output current value, and the second constant current driving section performs the chromaticity correction by adding this to the main current of each color as a correction current for chromaticity correction. . The second current adjusting unit 65 adjusts the current value added by the second constant current driving unit 64. For example, when correcting R (red), the lighting pulse generator 63 for red is used.
Lighting pulse signal generated by G (green), B (blue)
The second constant-current driving unit 64 for driving is also driven. Then, while supplying a main current to the red LEDs and supplying a correction current to the green and blue LEDs to light them, the chromaticity of red is corrected. The same means is used for chromaticity correction of other colors. For example, red for chromaticity correction of green,
The blue correction current is added, and the red and green correction currents are added for blue chromaticity correction.

As a result, when RGB is turned on as one pixel, the correction currents of the other two colors are added to the main currents of the LEDs of each color. For example, in the red LED, a main current for lighting red, a correction current for green correction, and a correction current for blue correction flow. The main current and the correction current for chromaticity correction are combined by the respective second current drive units.

The image display device according to the sixth embodiment described above has the following configuration. (1) A first current adjusting unit 61 that individually controls the main current of each color is provided. The gradation pulse width of the lighting pulse generator 63 is determined based on the gradation data received from the drive controller 51, and the main current is supplied from the first constant current driver 60 to the LED during this pulse effective period. To do. (2) Further, in the image display device of the sixth embodiment, the lighting pulse generated in the lighting pulse generation unit 63 for the LED of the chromaticity correction is used as the drive control signal in the second constant current drive units 64 of the other two colors. input. Then, based on the second current adjusting unit 65, a predetermined correction current for chromaticity correction is added to the main current of the LED corresponding to the correction color.

Due to such characteristics, in the image display device of the sixth embodiment, the first constant current driving unit 60 and the first current adjusting unit 6 are provided in the respective driving units 50 of the red, green and blue LEDs.
The main current to be output by 1 is adjusted, and the correction current added to the main current is driven and controlled by the second constant current drive unit 64 and the second current adjustment unit 65, so that each color LE
It is possible to make the individual variations uniform by performing D chromaticity correction.

[Embodiment 7] An image display apparatus according to Embodiment 7 of the present invention is shown in FIG. Constant current driving circuit in FIG. 13 is a RGB of LED _{L R,} L G, and _{L B,} each L
Outputs OUT _R , OUT _G , OUT _B connected to ED
A lighting pulse generator 63 _R , 63 _G , 63 _B, and
First current adjustment DA converter 61 which is the current adjustment unit 61 of
A _{R, 61A} G, _{61A B} and the second current adjustment DA converter 65A is the second current adjusting portion 65, the correction current switch SW1~6 a switch control constituting the second constant current driving portions 64 And a section 66. Hereinafter, referring to the constant current drive circuit for chromaticity correction shown in FIG.
A specific configuration of the image display device according to the present invention will be described.

The constant current drive circuit shown in FIG. 13 has one pixel
The output part of the LED to be controlled is output by RGB respectively._R,
OUT_G, OUT_BIt is composed of three output units. Each output
The constant current drive of each part can be controlled individually. In this example
Adjusts the brightness of each LED by gradation control by pulse width modulation.
I'm going. Specifically, the gradation reference clock (GC
LK) lighting pulse generator 63_R, 63_G, 63_BEnter
And pulse based on the gradation data (DATA1-3)
The width modulation is performed to control the lighting section. This lighting pulse signal
No. 1 regulates the main current flowing to each output unit by the first current adjustment.
DA converter 61A _R, 61A_G, 61A_BDecided by each
Output section OUT_R, OUT_G, OUT_BTo drive. First
Current adjustment DA converter 61A_R, 61A_G, 61A_BOh
And the second current adjustment DA converter 65A, respectively.
The data DAC_Data1 to 4 are input and controlled.
Be done. Here, as control data DAC_Data1 to 3
Is white balance correction data, surface brightness correction data,
There is elementary brightness correction data, etc., and control data DAC_Da
ta4 is chromaticity correction data.

In this embodiment, in order to correct the chromaticity of the LED of any color, the correction currents are added to the other two colors in the same lighting section to adjust the LED to have the predetermined chromaticity. That is, in order to correct one color, it is necessary to add a correction current to the other two colors, and therefore, it is necessary to add a total of six types of correction currents for the three colors. The constant current drive circuit shown in FIG. 13 includes correction current switches SW1 to SW6, and each correction current switch SW is time-divisionally turned on according to a chromaticity correction selection signal.

FIG. 14 shows an example of a time chart for the chromaticity correction operation. In this operation, one image frame whose frame signal is VSYNC (vertical synchronization signal) indicating the beginning of the image frame is divided into six, and the image transfer frame (Fram
Then, the image data is transferred in the image transfer frames 1 to 6 and the image display operation is performed. Flickering can be prevented by dividing one image frame into a plurality of image transfer frames and performing lighting display based on the same image data a plurality of times in each image transfer frame.

The chromaticity correction operation for each color is carried out for each image transfer frame divided into six. Each chromaticity correction current value to be the chromaticity correction target is transferred as chromaticity correction current data in the previous image transfer frame. That is, each chromaticity correction current data is transferred to the second current adjustment DA converter 65A in the previous image transfer frame, and the correction current switch SW is turned on to the chromaticity correction target LED in the next image transfer frame.
N to add a correction current. Correction current switch SW
Performs time-divisional addition control of the correction current according to the chromaticity correction selection signal. The correction current is added to the LEDs other than the chromaticity correction target LED from the second current adjustment DA converter 65A via the correction current switch SW. As described above, in each image transfer frame shown in FIG. 14, the step of transferring the chromaticity correction current data of the previous image transfer frame, and the chromaticity correction based on the chromaticity correction current data transferred in the previous image transfer frame. Based on the process in which the second current adjustment DA converter 65A supplies the current and the chromaticity correction selection signal, the switch control unit 6
6 includes the step of turning on the corresponding correction current switch SW.

For example, the R_g chromaticity correction data is R
The chromaticity correction current data for causing G (green) to emit light for chromaticity correction of the (red) LED is shown. The R_g chromaticity correction data is transferred in the image transfer frame 6, the data is held in the next image transfer frame 1, and the chromaticity correction current is reflected. Correction current switch S in the next image transfer frame 1
W3 is selected by the chromaticity correction selection signal and turned on, and the current adjustment D is performed based on the R_g chromaticity correction current data.
A correction current is supplied from the A converter 65A, and PWM control is performed by the lighting pulse generation unit 63. In this way, the G chromaticity correction current is applied during the period when the R LED is on. Similarly, the image transfer frame 1
To 6 are sequentially processed, and the correction current switches SW1 to SW6
Is switched to time division, and the chromaticity of the LEDs of all colors is corrected in one image frame period.

Here, LE is used in each image transfer frame.
Although the example of supplying the correction current for the D chromaticity correction has been described, the number of image transfer frames and in which image transfer frame the correction current is supplied can be appropriately set. The number of divided image frames to set the number of image transfer frames is determined from the viewpoint of flicker prevention of the image display device, and the correction current is supplied by the LE to be used.
It depends on the number of color tones of D and the number of color tones of the LED that is turned on for correction. For example, the number of image transfer frames may be eight, and the correction current may be supplied in six image transfer frames.

[0108]

As described above, the image display device and the control method thereof according to the present invention can make the chromaticity uniform for each pixel regardless of the chromaticity variation of light emitting elements such as LEDs.

Particularly, by configuring the correction data storage unit in the image display unit and the chromaticity correction unit being directly controlled based on the chromaticity correction data stored in the correction data storage unit, the same luminance is obtained. Thus, it becomes possible to manufacture color tone units, and it is possible to provide image display with excellent uniformity not only for each unit but also within the same unit.

Further, since it is easy to integrate the current supply section, the brightness correction section, the drive time control section, and the like in the drive section into an IC, the chromaticity correction section can be made into an IC. it can. Furthermore, when a large-sized display is composed of a plurality of image display units, each image display unit has a correction function, which has the effect of significantly improving maintainability such as replacement of image display unit units. To be Furthermore, the external image data control circuit side that supplies the image data to the image display device does not need to consider the variation of the light emitting elements, so that the external device can concentrate on the function of displaying an image on a uniform screen. As a result, it becomes possible to realize signal processing that enables higher quality image display.

As described above, the image display device and the control method thereof according to the present invention are provided with an inexpensive LED having variations in characteristics.
Is used, the manufacturing cost can be reduced, and the high-quality image display device having excellent reproducibility for the same data can be provided.

Furthermore, in the image display device according to the present invention, one current adjusting section is provided for each pixel for chromaticity correction, and the correction current for chromaticity correction of each color is turned on / off. By switching and adding by control, chromaticity correction of all colors can be performed in the image frame cycle of one image. With this configuration, chromaticity correction of all colors can be realized without using many current adjustment DA converter circuits and the like. In particular, the current adjustment DA converter is a part that requires a space because it is combined with resistors to form a circuit. The present invention is capable of controlling the chromaticity correction current of the light emitting element of one pixel by one circuit without separately providing the second current adjusting DA converter for each light emitting element. In addition to the above, it is possible to reduce the size of the circuit and contribute to the miniaturization of the device.

[Brief description of drawings]

FIG. 1 shows a plurality of color tones RGB in an image display unit of the present invention.
FIG. 6 is a conceptual diagram showing an example of a pixel including light emitting elements L _R , L _G , and L _B corresponding to FIG.

FIG. 2 is a conceptual diagram showing an example in which a reference chromaticity in the present invention is selected using a chromaticity diagram.

FIG. 3 is a block diagram showing a configuration of an image display device of the present invention.

FIG. 4 is a diagram showing an example of combining pulse drive currents in the chromaticity correction unit according to the first embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a distribution unit in the image display device of the present invention.

FIG. 6 is a conceptual diagram showing a drive current distribution flow in a distribution unit of the present invention for an R distribution block and an R combination block.

FIG. 7 is a diagram showing an example of a pulse drive current for one image frame time in the chromaticity correction unit according to the second embodiment of the present invention.

FIG. 8 is a diagram showing an example of a pulse drive current for one image frame time in the chromaticity correction unit according to the third embodiment of the present invention.

FIG. 9 is a conceptual diagram of a chromaticity correction system used in a chromaticity correction method for an image display device according to a fourth embodiment of the present invention.

FIG. 10 is a block diagram showing a configuration of a display unit according to an image display device of Example 5 of the present invention.

FIG. 11 is a block diagram showing a configuration of an image display device according to a fifth embodiment of the present invention.

FIG. 12 is a block diagram showing an example of an image display device according to a sixth embodiment of the present invention.

FIG. 13 is a block diagram showing a configuration of an image display device according to a seventh embodiment of the present invention.

FIG. 14 is a time chart showing the operation of the image display device of FIG. 13 for chromaticity correction.

[Explanation of symbols]

1 ... LED unit L ... pixel _{L R, L G, L B} ··· light emitting element 10 ... display unit 11 ... chromaticity correcting unit 111a, b, c ... R distribution block, G distribution block, B distribution block 112a, b, c ... R combination block, G combination block, B combination block 12 ... Driving time control unit 13 ... Luminance correction unit 14 ... Current supply unit 17 ... ..Common driver 18 ... address generation unit 19 ... image input unit 31 ... correction data control unit 32 ... correction data storage unit 33 ... communication unit 41 ... luminance / chromaticity correction device 42 ... Luminance / chromaticity meter 50 ... Drive unit 50A ... Vertical drive unit 50B ... Horizontal drive unit 50b ... LED driver 51 ... Drive control unit 52 ... First current Drive unit 53 ... Second current drive unit 54 ... Selector 6 ... first constant current driving portions 61 ... first current controller _{61A, 61A R, 61A G,} 61A B ··· first current adjustment DA converter 62,62 _{R, 62} G, _{62 B} ... Main current switch 63, 63 _R , 63 _G , 63 _B ... Lighting pulse generation unit 64 ... Second constant current drive unit 65 ... Second current adjustment unit 65A ... 2 current adjustment DA converter 66 ... Switch control parts OUT _R , OUT _G , OUT _B ... Output parts SW1, SW2, SW3, SW4, SW5, SW6 ...
・ Correction current switch

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI Theme Coat (reference) G09G 3/20 642 G09G 3/20 642J (72) Inventor Yoshiyuki Nakano 491-1 Oka, Kaminaka-cho, Anan City, Tokushima Prefecture Nichia Kagaku Kogyo Co., Ltd. (72) Inventor Ryuhei Tsuji 100 491, Oka, Kaminaka-cho, Anan-shi, Tokushima Prefecture F-term inside Nichia Kagaku Kogyo Co., Ltd.

Claims (11)

[Claims] 1. A light emitting element having a plurality of color tones is arranged for each pixel, and a drive current supplied to each of the light emitting elements having a plurality of color tones is adjusted for each pixel based on image data relating to the plurality of color tones. The first current adjusting unit (61 _R , 6
1 _G , 61 _B ) and light emission corresponding to one or more other color tones of the pixel in order to correct the color tone of the light emitting element corresponding to at least one of the plurality of color tones of each pixel. An image display device comprising a second current adjusting section (65) for adjusting a correction current supplied to an element, wherein one image frame having VSYNC as a frame signal is divided into a plurality of image transfer frames. When performing the image display operation based on the same image data in each image transfer frame, the correction current for correcting the color tone of the light emitting element of any one color tone in at least one image transfer frame is set to another value. The correction current supplied to the light emitting element of any one of the color tones and the correction current supplied to any one of the other light emitting elements to correct the color of the one of the light emitting elements for each image transfer frame is switched. The image display apparatus characterized by being configured to implement a time division color correction with respect to the light-emitting element of the plurality of color tone Rukoto. 2. The image display device according to claim 1, wherein the color tones of the light emitting elements are red, green and blue. 3. The image display device according to claim 1, wherein the image display device further corrects the brightness of each light emitting element. 4. The first current adjusting section (61) includes a first first
Current adjusting section (61) supplies a drive current to the light emitting element of one color tone, and the second current adjusting section (65) includes one second current adjusting section (6).
5. The image display device according to claim 1, wherein 5) supplies a correction current to the light emitting elements of a plurality of colors. 5. The number of image transfer frames obtained by dividing an image frame, and which image transfer frame is to be supplied with a correction current for which color tone of the light emitting element can be set. Item 5. The image display device according to any one of items 1 to 4. 6. The first current adjusting unit (61) is a first current controller.
Adjustment DA converter (61A _R, 61A_G, 61A_B) And the second
The current adjustment unit (65) of the second current adjustment DA converter (65A)
It exists, It is characterized by the above-mentioned.
Image display device. 7. The image display device further includes at least one lighting pulse generation unit (63 _R , 63 _G , 63) for generating a lighting pulse for controlling light emission of each of the light emitting elements.
_B ) and a plurality of main current switches (6) whose ON / OFF is controlled by the lighting pulse generator (63 _R , 63 _G , 63 _B ) respectively.
2 _R , 62 _G , 62 _B ) and a plurality of correction current switches (SW1) for adjusting the correction current.
-6) and a switch control section (66, 66, 66) for ON / OFF controlling the correction current switch (SW1-6), and the first current adjusting section (61 _R , 61 _G , 61 _B). ) Adjusts the drive current supplied to each light emitting element via the main current switch (62 _R , 62 _G , 62 _B ), and the second current adjusting section (65) controls the correction current switch (65). S
6. The color tone correction is performed for each light emitting element by adjusting the correction current supplied to each light emitting element via W1-6) and adding the correction current to the drive current. Or the image display device described above. 8. The lighting pulse generator (63 _R , 63 _G , 63 _B )
The image display device according to claim 7, wherein the pulse width modulation is performed on the gradation data based on the gradation reference clock to control the lighting section. 9. The switch control section (66, 66, 66) controls the O of the correction current switch (SW1-6) in response to a color tone correction selection signal.
The image display device according to claim 7, which performs N / OFF control. 10. Light emitting elements L _R , L _G , L _B corresponding to a plurality of color tones RGB are arranged for each pixel, and the light emission is performed for each pixel based on image data D _R , D _G , D _B regarding RGB. The light emission amounts A _{R of} the elements L _R , L _G , and L _B ,
An image display control method for controlling multi-color emission by controlling A _G and A _B , wherein one image frame having VSYNC as a frame signal is divided into a plurality of image transfer frames, and the same image transfer frame is used for each image transfer frame. When performing the image display operation based on the image data, in at least one image transfer frame, the light emitting element Li (i = R, G, B) relating to at least one color tone of RGB of each pixel is changed to the image data Di. When light is emitted on the basis of the light emission amount A based on the image data Dk, the light emitting element Lk (k ≠ i) of another one or more tones of the pixel is emitted according to the image data Dk.
The light emission amount Ai of the light emitting element Li
In accordance with the above, the light emitting element Lk is further caused to emit light with the light emitting amount A′k, the light emitting amount of the light emitting element Lk is set to Ak + A′k, and the light emitting amount A′k for correction is added in Then, in order to correct any one of the color tones, the light emitting element of any one of the other colors is caused to emit light with the light emission amount A′k, and in order to correct the color of any one of the light emitting elements for each image transfer frame, An image display control method configured to realize color tone correction for light emitting elements of a plurality of color tones in a time-sharing manner by switching the light emission amount A′k that causes one of the light emitting elements to emit light. 11. A light emitting element having a plurality of color tones is arranged for each pixel, and a drive current supplied to each of the light emitting elements having a plurality of color tones is adjusted for each pixel based on image data relating to the plurality of color tones. The first current adjusting unit (61 _R , 6
1 _G , 61 _B ) and light emission corresponding to one or more other color tones of the pixel in order to correct the color tone of the light emitting element corresponding to at least one of the plurality of color tones of each pixel. A control method for an image display device, comprising: a second current adjusting section (65) for adjusting a correction current supplied to an element, for correcting the brightness and color tone of the image display device, the method being compatible with a plurality of color tones. A luminance / color tone calculation step of calculating the luminance and color tone of the light emitting element corresponding to each color tone of the display device for each pixel by a light emission intensity detector having a light receiving element, and calculation for each pixel in the luminance / color tone calculation step Luminance / color tone difference calculation step of comparing the luminance and color tone of the light emitting element corresponding to each color tone with the reference luminance and the reference color tone, and calculating the luminance difference and the color tone difference, and the luminescent element corresponding to each color tone. The drive current supplied to the child is adjusted by the first current adjustment (61 _R , 61 _G , 61 _B ) and is supplied based on the brightness difference and color difference calculated in the brightness / color difference calculation step. A correction step of correcting each pixel brightness and color tone to a reference brightness and a reference color tone by adjusting the correction current by the second current adjusting section (65) and adding the adjusted correction current to the drive current; , A correction data storing step of storing correction data relating to control of a drive current supplied to the light emitting element of each color tone in the image display device for each pixel, and a plurality of one image frame using VSYNC as a frame signal When the image display operation is performed based on the same image data in each image transfer frame by dividing the image transfer frame, the correction is performed in at least one image transfer frame. A step of supplying a correction current for performing brightness / color tone correction based on data to the light emitting element corresponding to the one or more other color tones and adding the correction current to the drive current. In order to supply the correction current for correcting the color tone and the brightness of the light emitting element of one color tone to the light emitting element of any one other color tone, and to correct the color tone of any one light emitting element for each image transfer frame. A method of controlling an image display device, comprising: a step of performing color tone correction and luminance correction for light emitting elements of a plurality of color tones in a time division manner by switching a correction current supplied to any one other light emitting element.