CN101191955B - LCD device - Google Patents

Abstract

The present invention provides a liquid crystal display device, comprising a liquid crystal display panel and a backlight module. The backlight module and the liquid crystal display panel are stacked. The backlight module comprises a circuit and a light source array. The circuit comprises a first port supplying power for the light source array. The light source array comprises a plurality of red light emitting diodes, a plurality of green light emitting diodes and a plurality of blue light emitting diodes, which are connected with each other in series, wherein, the numbers of the red, green and blue light emitting diodes are respectively a, b and c. The backlight module can coordinate with the liquid crystal display device to display a coordinate of the preconcerted color, and the values of a, b and c can be determined through the chromaticity coordinate of the coordinate in preconcerted color. The present invention is low in cost.

Description

Liquid crystal display device having a plurality of pixel electrodes

Technical Field

The invention relates to a liquid crystal display device.

Background

Liquid crystal display devices are becoming widespread in use due to their characteristics of low radiation, light weight, small size, low power consumption, and the like, and their kinds are becoming more and more popular with the maturity and innovation of related technologies. A liquid crystal display ("lcd"), which is a non-self-luminous display device, generally includes a backlight module for providing a planar light required for displaying and a liquid crystal display panel for displaying images.

In the backlight module, a Light source for providing Light is generally a Cold Cathode Fluorescent Lamp (CCFL) or a Light Emitting Diode (LED). Among them, the red, green and blue leds have been widely noticed as backlight sources because of their high color saturation.

Please refer to fig. 1, which is a schematic structural diagram of a liquid crystal display device disclosed in the prior art, the liquid crystal display device 1 includes a liquid crystal display panel 10 and a backlight module 11, and the backlight module 11 and the liquid crystal display panel 10 are stacked and configured to provide display light for the liquid crystal display panel 10.

The lcd panel 10 includes a first substrate 100, a second substrate 120 and a liquid crystal layer 110. The first substrate 100 and the second substrate 120 are disposed opposite to each other, and the liquid crystal layer 110 is interposed between the first substrate 100 and the second substrate 120. The first substrate 100 includes a color filter layer 130, and the color filter layer 130 is disposed on a surface of the first substrate 100 near the liquid crystal layer 110. The color filter layer 130 includes a plurality of red filter units 131, a plurality of green filter units 132, and a plurality of blue filter units 133 for displaying images in full color.

Please refer to fig. 2, which is a schematic structural diagram of a backlight module of the liquid crystal display device of fig. 1. The backlight module 11 includes a power supply circuit 111 and a light source array 112. The power supply circuit 111 includes a first port 113, a second port 114, and a third port 115. The light source array 112 includes a plurality of red leds 116, a plurality of green leds 117 and a plurality of blue leds 118, wherein the plurality of red leds 116 are connected in series to the first port 113, the plurality of green leds 117 are connected in series to the second port 114, and the plurality of blue leds 118 are connected in series to the third port 115.

Since the red, green and blue leds 116, 117 and 118 have the same number and different frequency spectrums, different operating voltages of the red, green and blue leds 116, 117 and 118 are required to be respectively provided to control the light intensities of the red, green and blue leds 116, 117 and 118 in order to make the backlight module 11 emit white light. Therefore, the first port 113, the second port 114 and the third port 115 respectively provide different voltages, so that the red, green and blue leds 116, 117 and 118 respectively have different operating currents, thereby achieving the purpose that the three colors of light emitted by the red, green and blue leds 116, 117 and 118 can be mixed to form white light required for displaying.

However, in the backlight module 11, three ports 113, 114 and 115 with different voltages are required to supply power to the same number of red, green and blue leds 116, 117 and 118, which makes the power supply circuit structure complicated and the cost high.

Disclosure of Invention

In order to solve the problems of complicated structure and high cost of the power supply circuit of the liquid crystal display device, it is necessary to provide a liquid crystal display device with a simple structure and low cost of the power supply circuit.

A liquid crystal display device comprises a liquid crystal display panel and a backlight module, wherein the backlight module and the liquid crystal display panel are arranged in a laminated manner; the backlight module comprises a circuit and a light source array, the circuit comprises a first port which supplies power to the light source array, the light source array comprises a plurality of red light-emitting diodes, a plurality of green light-emitting diodes and a plurality of blue light-emitting diodes which are connected in series, wherein the number of the red light-emitting diodes, the number of the green light-emitting diodes and the number of the blue light-emitting diodes are a, b and c respectively, the backlight module can be matched with the liquid crystal display device to display a preset color coordinate, the values of a, b and c can be determined by the chromaticity coordinate of the preset color coordinate, the frequency spectrum of the red light-emitting diodes is S (R), the frequency spectrum of the green light-emitting diodes is S (G), (B) and the penetration frequency spectrum of the liquid crystal display panel in a red display state is tau_R(λ) a transmission spectrum in a green-displaying state is τ_G(λ) a transmission spectrum in a state of displaying blue is τ_R(λ), the chromaticity coordinate of red displayed by the liquid crystal display panel is a predetermined value (xR, yR), the chromaticity coordinate of green displayed by the liquid crystal display panel is a predetermined value (xG, yG), the chromaticity coordinate of blue displayed by the liquid crystal display panel is a predetermined value (xB, yB),

for spectral tristimulus values, a, B, C are unknowns, by solving the system of equations:

<math><mrow><mfenced open='{' close=''><mtable><mtr><mtd><mi>Xin</mi><mo>=</mo><mi>S</mi><mrow><mo>(</mo><mi>n</mi><mo>)</mo></mrow><msub><mi>&tau;</mi><mi>n</mi></msub><mrow><mo>(</mo><mi>&lambda;</mi><mo>)</mo></mrow><mover><mi>x</mi><mo>&OverBar;</mo></mover><mrow><mo>(</mo><mi>&lambda;</mi><mo>)</mo></mrow></mtd></mtr><mtr><mtd><mi>Yin</mi><mo>=</mo><mi>S</mi><mrow><mo>(</mo><mi>n</mi><mo>)</mo></mrow><msub><mi>&tau;</mi><mi>n</mi></msub><mrow><mo>(</mo><mi>&lambda;</mi><mo>)</mo></mrow><mover><mi>y</mi><mo>&OverBar;</mo></mover><mrow><mo>(</mo><mi>&lambda;</mi><mo>)</mo></mrow></mtd></mtr><mtr><mtd><mi>Zin</mi><mo>=</mo><mi>S</mi><mrow><mo>(</mo><mi>n</mi><mo>)</mo></mrow><msub><mi>&tau;</mi><mi>n</mi></msub><mrow><mo>(</mo><mi>&lambda;</mi><mo>)</mo></mrow><mover><mi>z</mi><mo>&OverBar;</mo></mover><mrow><mo>(</mo><mi>&lambda;</mi><mo>)</mo></mrow></mtd></mtr></mtable></mfenced><mo>,</mo><mi>i</mi><mo>=</mo><mn>1,2,3</mn><mo>,</mo><mi>n</mi><mo>=</mo><mi>R</mi><mo>,</mo><mi>G</mi><mo>,</mo><mi>B</mi></mrow></math>

<math><mrow><mi>XRR</mi><mo>=</mo><mrow><mo>(</mo><mi>A</mi><mo>,</mo><mi>B</mi><mo>,</mo><mi>C</mi><mo>)</mo></mrow><mo>&CenterDot;</mo><mfenced open='[' close=']'><mtable><mtr><mtd><mi>X</mi><mn>1</mn><mi>R</mi></mtd></mtr><mtr><mtd><mi>X</mi><mn>2</mn><mi>R</mi></mtd></mtr><mtr><mtd><mi>X</mi><mn>3</mn><mi>R</mi></mtd></mtr></mtable></mfenced></mrow></math> <math><mrow><mi>XGR</mi><mo>=</mo><mrow><mo>(</mo><mi>A</mi><mo>,</mo><mi>B</mi><mo>,</mo><mi>C</mi><mo>)</mo></mrow><mo>&CenterDot;</mo><mfenced open='[' close=']'><mtable><mtr><mtd><mi>X</mi><mn>1</mn><mi>G</mi></mtd></mtr><mtr><mtd><mi>X</mi><mn>2</mn><mi>G</mi></mtd></mtr><mtr><mtd><mi>X</mi><mn>3</mn><mi>G</mi></mtd></mtr></mtable></mfenced></mrow></math> <math><mrow><mi>XBR</mi><mo>=</mo><mrow><mo>(</mo><mi>A</mi><mo>,</mo><mi>B</mi><mo>,</mo><mi>C</mi><mo>)</mo></mrow><mo>&CenterDot;</mo><mfenced open='[' close=']'><mtable><mtr><mtd><mi>X</mi><mn>1</mn><mi>B</mi></mtd></mtr><mtr><mtd><mi>X</mi><mn>2</mn><mi>B</mi></mtd></mtr><mtr><mtd><mi>X</mi><mn>3</mn><mi>B</mi></mtd></mtr></mtable></mfenced></mrow></math>

<math><mrow><mi>YRG</mi><mo>=</mo><mrow><mo>(</mo><mi>A</mi><mo>,</mo><mi>B</mi><mo>,</mo><mi>C</mi><mo>)</mo></mrow><mo>&CenterDot;</mo><mfenced open='[' close=']'><mtable><mtr><mtd><mi>Y</mi><mn>1</mn><mi>R</mi></mtd></mtr><mtr><mtd><mi>Y</mi><mn>2</mn><mi>R</mi></mtd></mtr><mtr><mtd><mi>Y</mi><mn>3</mn><mi>R</mi></mtd></mtr></mtable></mfenced></mrow></math> <math><mrow><mi>YGG</mi><mo>=</mo><mrow><mo>(</mo><mi>A</mi><mo>,</mo><mi>B</mi><mo>,</mo><mi>C</mi><mo>)</mo></mrow><mo>&CenterDot;</mo><mfenced open='[' close=']'><mtable><mtr><mtd><mi>Y</mi><mn>1</mn><mi>G</mi></mtd></mtr><mtr><mtd><mi>Y</mi><mn>2</mn><mi>G</mi></mtd></mtr><mtr><mtd><mi>Y</mi><mn>3</mn><mi>G</mi></mtd></mtr></mtable></mfenced></mrow></math> <math><mrow><mi>YBG</mi><mo>=</mo><mrow><mo>(</mo><mi>A</mi><mo>,</mo><mi>B</mi><mo>,</mo><mi>C</mi><mo>)</mo></mrow><mo>&CenterDot;</mo><mfenced open='[' close=']'><mtable><mtr><mtd><mi>Y</mi><mn>1</mn><mi>B</mi></mtd></mtr><mtr><mtd><mi>Y</mi><mn>2</mn><mi>B</mi></mtd></mtr><mtr><mtd><mi>Y</mi><mn>3</mn><mi>B</mi></mtd></mtr></mtable></mfenced></mrow></math>

<math><mrow><mi>ZRB</mi><mo>=</mo><mrow><mo>(</mo><mi>A</mi><mo>,</mo><mi>B</mi><mo>,</mo><mi>C</mi><mo>)</mo></mrow><mo>&CenterDot;</mo><mfenced open='[' close=']'><mtable><mtr><mtd><mi>Z</mi><mn>1</mn><mi>R</mi></mtd></mtr><mtr><mtd><mi>Z</mi><mn>2</mn><mi>R</mi></mtd></mtr><mtr><mtd><mi>Z</mi><mn>3</mn><mi>R</mi></mtd></mtr></mtable></mfenced></mrow></math> <math><mrow><mi>ZGB</mi><mo>=</mo><mrow><mo>(</mo><mi>A</mi><mo>,</mo><mi>B</mi><mo>,</mo><mi>C</mi><mo>)</mo></mrow><mo>&CenterDot;</mo><mfenced open='[' close=']'><mtable><mtr><mtd><mi>Z</mi><mn>1</mn><mi>G</mi></mtd></mtr><mtr><mtd><mi>Z</mi><mn>2</mn><mi>G</mi></mtd></mtr><mtr><mtd><mi>Z</mi><mn>3</mn><mi>G</mi></mtd></mtr></mtable></mfenced></mrow></math> <math><mrow><mi>ZBB</mi><mo>=</mo><mrow><mo>(</mo><mi>A</mi><mo>,</mo><mi>B</mi><mo>,</mo><mi>C</mi><mo>)</mo></mrow><mo>&CenterDot;</mo><mfenced open='[' close=']'><mtable><mtr><mtd><mi>Z</mi><mn>1</mn><mi>B</mi></mtd></mtr><mtr><mtd><mi>Z</mi><mn>2</mn><mi>B</mi></mtd></mtr><mtr><mtd><mi>Z</mi><mn>3</mn><mi>B</mi></mtd></mtr></mtable></mfenced></mrow></math>

$\mathrm{xR}=\frac{\mathrm{XRR}}{\mathrm{XRR}+\mathrm{YRG}+\mathrm{ZRB}},$ $\mathrm{yR}=\frac{\mathrm{YRG}}{\mathrm{XRR}+\mathrm{YRG}+\mathrm{ZRB}}$

$\mathrm{xG}=\frac{\mathrm{XGR}}{\mathrm{XGR}+\mathrm{YGG}+\mathrm{ZGB}},$ $\mathrm{yG}=\frac{\mathrm{YGG}}{\mathrm{XGR}+\mathrm{YGG}+\mathrm{ZGB}}$

$\mathrm{xB}=\frac{\mathrm{XBR}}{\mathrm{XBR}+\mathrm{YBG}+\mathrm{ZBB}},$ $\mathrm{yB}=\frac{\mathrm{YBG}}{\mathrm{XBR}+\mathrm{YBG}+\mathrm{ZBB}}$

if the ratio of A to B to C is determined, a, B and C are integer solutions satisfying the ratio of A to B to C within an allowable error range.

Compared with the prior art, the liquid crystal display device provided by the invention has the advantages that the first port is adopted to provide a voltage to supply power to the light source array, and the corresponding design is carried out according to the number of the red, green and blue light-emitting diodes, so that the effect of realizing the work of three ports in the prior art is realized, and the cost is reduced. And the circuit only outputs one voltage, so that the structure of the power supply circuit is simple.

Drawings

Fig. 1 is a schematic structural diagram of a liquid crystal display device according to the prior art.

FIG. 2 is a schematic view of a backlight module of the LCD device of FIG. 1.

Fig. 3 is a schematic structural view of a liquid crystal display device according to a first embodiment of the present invention.

FIG. 4 is a schematic view of a backlight module of the LCD device shown in FIG. 3.

FIG. 5 is a 1391CIE-xy chromaticity diagram published by the International Commission on illumination.

FIG. 6 is a schematic view of a backlight module of a liquid crystal display device according to a second embodiment of the present invention.

Detailed Description

Fig. 3 is a schematic structural diagram of a liquid crystal display device according to a first embodiment of the invention. The LCD device 2 includes an LCD panel 20 and a backlight module 21. The backlight module 21 is stacked with the liquid crystal display panel 20 and provides display light for the liquid crystal display panel 20.

The lcd panel 20 includes a first substrate 200, a second substrate 220 and a liquid crystal layer 210. The first substrate 200 is disposed opposite to the second substrate 220, and the liquid crystal layer 210 is interposed between the first substrate 200 and the second substrate 220.

A first polarizer 290 is disposed on a surface of the first substrate 200 away from the liquid crystal layer 210. A color filter layer 230, a common electrode layer 240 and a first alignment layer 250 are sequentially disposed on the surface of the first substrate 200 close to the liquid crystal layer 210. The color filter layer 230 includes a plurality of red filter units 231, a plurality of green filter units 232, and a plurality of blue filter units 233, and they are arranged in a regular and repeated manner.

A second polarizer 219 is disposed on a surface of the second substrate 220 away from the liquid crystal layer 210. A pixel electrode layer 221 and a second alignment layer 222 are sequentially disposed on the surface of the second substrate 220 close to the liquid crystal layer 210.

Please refer to fig. 4, which is a schematic structural diagram of a backlight module of the lcd device shown in fig. 3. The backlight module 21 includes a power supply circuit 211 and a light source array 214. The power supply circuit 211 has a first port 212 that provides a voltage to power the light source array 214. The light source array 214 includes a plurality of red light emitting diodes 215, a plurality of green light emitting diodes 216, and a plurality of blue light emitting diodes 217. The plurality of red leds 215, the plurality of green leds 216, and the plurality of blue leds 217 are sequentially connected in series and connected to the first port 212. The number of the red light emitting diodes 215 is a, the number of the green light emitting diodes 216 is b, and the number of the blue light emitting diodes 217 is c.

Please refer to FIG. 5, which is a schematic diagram of 1391CIE-xy chromaticity diagram published by the International Commission on illumination. Visible light of any wavelength in the figure can be uniquely represented by the chromaticity coordinates of the 1931CIE-XYZ standard chromaticity system. The numbers a, b, and c of the red, green, and blue leds 215, 216, and 217 are determined such that the light emitted from the backlight module 21 can display predetermined red, green, blue, and other colors in cooperation with the lcd panel 20. Wherein the predetermined red, green, blue and other colors may be measured by chromaticity coordinates of the 1931CIE-XYZ standard chromaticity system published by the international commission on illumination.

Before explaining how to determine a, b, c, the basic concept and principle of the 1931CIE-XYZ standard chromaticity system will be briefly described.

The arbitrary color can be expressed by the following formula:

C＝X[X]+Y[Y]+Z[Z]

wherein C represents an arbitrary color, and [ X ], [ Y ], and [ Z ] are three primary colors of unit amount, and X, Y, Z is a tristimulus value.

The tristimulus value may be determined by the following formula:

<math><mrow><mfenced open='{' close=''><mtable><mtr><mtd><mi>X</mi><mo>=</mo><mi>k&Sigma;S</mi><mrow><mo>(</mo><mi>&lambda;</mi><mo>)</mo></mrow><mi>&tau;</mi><mrow><mo>(</mo><mi>&lambda;</mi><mo>)</mo></mrow><mover><mi>x</mi><mo>&OverBar;</mo></mover><mrow><mo>(</mo><mi>&lambda;</mi><mo>)</mo></mrow><mi>&Delta;&lambda;</mi></mtd></mtr><mtr><mtd><mi>Y</mi><mo>=</mo><mi>k&Sigma;S</mi><mrow><mo>(</mo><mi>&lambda;</mi><mo>)</mo></mrow><mi>&tau;</mi><mrow><mo>(</mo><mi>&lambda;</mi><mo>)</mo></mrow><mover><mi>y</mi><mo>&OverBar;</mo></mover><mrow><mo>(</mo><mi>&lambda;</mi><mo>)</mo></mrow><mi>&Delta;&lambda;</mi></mtd></mtr><mtr><mtd><mi>Z</mi><mo>=</mo><mi>k&Sigma;S</mi><mrow><mo>(</mo><mi>&lambda;</mi><mo>)</mo></mrow><mi>&tau;</mi><mrow><mo>(</mo><mi>&lambda;</mi><mo>)</mo></mrow><mover><mi>z</mi><mo>&OverBar;</mo></mover><mrow><mo>(</mo><mi>&lambda;</mi><mo>)</mo></mrow><mi>&Delta;&lambda;</mi></mtd></mtr></mtable></mfenced><mo>-</mo><mo>-</mo><mo>-</mo><mrow><mo>(</mo><mn>1</mn><mo>)</mo></mrow></mrow></math>

τ(λ)＝∏τ_i(λ)

wherein,

called spectral tristimulus values, S (λ) is the source spectrum, τ (λ) is the penetration spectrum, k is the parameter, and λ is the wavelength.

The chromaticity coordinate formula of the 1931CIE-XYZ standard chromaticity system can be expressed as:

$x=\frac{X}{X+Y+Z},$ $y=\frac{Y}{X+Y+Z}---\left(2\right)$

the following describes the steps for determining the number of the red, green and blue light emitting diodes in detail.

Firstly, acquiring required parameters;

obtaining the light source spectra S (R), S (G), S (B) corresponding to the red, green, blue LEDs 215, 216 and 217 at the same working current, and the transmission spectrum tau of the first polarizer 290₂(lambda), transmission spectrum tau of the second polarizer 219₃(λ), transmission spectrum τ of pixel electrode layer 221₄(λ), penetration spectrum τ of common electrode layer 240₄(λ), penetration spectrum τ of the first alignment layer 250₅(λ), the transmission spectrum τ of the second alignment layer 222₆(λ), transmission spectrum τ of red filter unit 231 of color filter layer 230_1R(λ), penetration spectrum τ of green filter unit 232_1G(λ), penetration spectrum τ of red filter 233_1B(λ), and spectral tristimulus values table.

Secondly, when the single red, green and blue light emitting diodes 215, 216 and 217 are respectively used as light sources, the liquid crystal display device 2 displays tristimulus values of red, green and blue;

assuming that a single red led 215 is used as the light source array 214, the lcd device 2 displays red, green and blue colors respectively through the red, green and blue color filter units 231, 232 and 233, and calculates the tri-stimulus values of the displayed red, green and blue colors according to the formula (1). The green light emitting diode 216 and the blue light emitting diode 217 are sequentially changed to calculate the same content. That is, the values of the variables listed in the following table were calculated:

thirdly, according to the superposition principle, when a plurality of light-emitting diodes are calculated to be used as light sources, the liquid crystal display device 2 displays the tristimulus values of red, green and blue;

according to the Grassman's law, the human eye's visual response should depend on the algebraic sum of the red, green and blue components, i.e. the ratio of which determines the visual color. Therefore, it is assumed that the number of the red leds 215 is a, the number of the green leds 216 is b, and the number of the blue leds 217 is c. When the light source array 214 is calculated based on the principle of superposition, the liquid crystal display device 2 displays three stimulus values of red, green, and blue. That is, the values of the variables listed in the following table were calculated:

wherein, the specific calculation formula of each variable is expressed by a matrix as:

<math><mrow><mi>XRR</mi><mo>=</mo><mrow><mo>(</mo><mi>a</mi><mo>,</mo><mi>b</mi><mo>,</mo><mi>c</mi><mo>)</mo></mrow><mo>&CenterDot;</mo><mfenced open='[' close=']'><mtable><mtr><mtd><mi>X</mi><mn>1</mn><mi>R</mi></mtd></mtr><mtr><mtd><mi>X</mi><mn>2</mn><mi>R</mi></mtd></mtr><mtr><mtd><mi>X</mi><mn>3</mn><mi>R</mi></mtd></mtr></mtable></mfenced></mrow></math> <math><mrow><mi>XGR</mi><mo>=</mo><mrow><mo>(</mo><mi>a</mi><mo>,</mo><mi>b</mi><mo>,</mo><mi>c</mi><mo>)</mo></mrow><mo>&CenterDot;</mo><mfenced open='[' close=']'><mtable><mtr><mtd><mi>X</mi><mn>1</mn><mi>G</mi></mtd></mtr><mtr><mtd><mi>X</mi><mn>2</mn><mi>G</mi></mtd></mtr><mtr><mtd><mi>X</mi><mn>3</mn><mi>G</mi></mtd></mtr></mtable></mfenced></mrow></math> <math><mrow><mi>XBR</mi><mo>=</mo><mrow><mo>(</mo><mi>a</mi><mo>,</mo><mi>b</mi><mo>,</mo><mi>c</mi><mo>)</mo></mrow><mo>&CenterDot;</mo><mfenced open='[' close=']'><mtable><mtr><mtd><mi>X</mi><mn>1</mn><mi>B</mi></mtd></mtr><mtr><mtd><mi>X</mi><mn>2</mn><mi>B</mi></mtd></mtr><mtr><mtd><mi>X</mi><mn>3</mn><mi>B</mi></mtd></mtr></mtable></mfenced></mrow></math>

$\mathrm{YRG}=(a,b,c)\left[\begin{array}{c}Y1R\\ Y2R\\ Y3R\end{array}\right]$ <math><mrow><mi>YGG</mi><mo>=</mo><mrow><mo>(</mo><mi>a</mi><mo>,</mo><mi>b</mi><mo>,</mo><mi>c</mi><mo>)</mo></mrow><mo>&CenterDot;</mo><mfenced open='[' close=']'><mtable><mtr><mtd><mi>Y</mi><mn>1</mn><mi>G</mi></mtd></mtr><mtr><mtd><mi>Y</mi><mn>2</mn><mi>G</mi></mtd></mtr><mtr><mtd><mi>Y</mi><mn>3</mn><mi>G</mi></mtd></mtr></mtable></mfenced></mrow></math> <math><mrow><mi>YBG</mi><mo>=</mo><mrow><mo>(</mo><mi>a</mi><mo>,</mo><mi>b</mi><mo>,</mo><mi>c</mi><mo>)</mo></mrow><mo>&CenterDot;</mo><mfenced open='[' close=']'><mtable><mtr><mtd><mi>Y</mi><mn>1</mn><mi>B</mi></mtd></mtr><mtr><mtd><mi>Y</mi><mn>2</mn><mi>B</mi></mtd></mtr><mtr><mtd><mi>Y</mi><mn>3</mn><mi>B</mi></mtd></mtr></mtable></mfenced></mrow></math>

<math><mrow><mi>ZRB</mi><mo>=</mo><mrow><mo>(</mo><mi>a</mi><mo>,</mo><mi>b</mi><mo>,</mo><mi>c</mi><mo>)</mo></mrow><mo>&CenterDot;</mo><mfenced open='[' close=']'><mtable><mtr><mtd><mi>Z</mi><mn>1</mn><mi>R</mi></mtd></mtr><mtr><mtd><mi>Z</mi><mn>2</mn><mi>R</mi></mtd></mtr><mtr><mtd><mi>Z</mi><mn>3</mn><mi>R</mi></mtd></mtr></mtable></mfenced></mrow></math> <math><mrow><mi>ZGB</mi><mo>=</mo><mrow><mo>(</mo><mi>a</mi><mo>,</mo><mi>b</mi><mo>,</mo><mi>c</mi><mo>)</mo></mrow><mo>&CenterDot;</mo><mfenced open='[' close=']'><mtable><mtr><mtd><mi>Z</mi><mn>1</mn><mi>G</mi></mtd></mtr><mtr><mtd><mi>Z</mi><mn>2</mn><mi>G</mi></mtd></mtr><mtr><mtd><mi>Z</mi><mn>3</mn><mi>G</mi></mtd></mtr></mtable></mfenced></mrow></math> <math><mrow><mi>ZBB</mi><mo>=</mo><mrow><mo>(</mo><mi>a</mi><mo>,</mo><mi>b</mi><mo>,</mo><mi>c</mi><mo>)</mo></mrow><mo>&CenterDot;</mo><mfenced open='[' close=']'><mtable><mtr><mtd><mi>Z</mi><mn>1</mn><mi>B</mi></mtd></mtr><mtr><mtd><mi>Z</mi><mn>2</mn><mi>B</mi></mtd></mtr><mtr><mtd><mi>Z</mi><mn>3</mn><mi>B</mi></mtd></mtr></mtable></mfenced><mo>-</mo><mo>-</mo><mo>-</mo><mrow><mo>(</mo><mn>3</mn><mo>)</mo></mrow></mrow></math>

the calculation result is an equation containing undetermined amounts a, b, and c.

Fourthly, converting the three stimuli into chromaticity coordinates;

the tristimulus values calculated above are converted into chromaticity coordinates according to equation (2).

Namely, it is $\mathrm{xR}=\frac{\mathrm{XRR}}{\mathrm{XRR}+\mathrm{YRG}+\mathrm{ZRB}},$ $\mathrm{yR}=\frac{\mathrm{YRG}}{\mathrm{XRR}+\mathrm{YRG}+\mathrm{ZRB}}$

$\mathrm{xG}=\frac{\mathrm{XGR}}{\mathrm{XGR}+\mathrm{YGG}+\mathrm{ZGB}},$ $\mathrm{yG}=\frac{\mathrm{YGG}}{\mathrm{XGR}+\mathrm{YGG}+\mathrm{ZGB}}$ (4)

$\mathrm{xB}=\frac{\mathrm{XBR}}{\mathrm{XBR}+\mathrm{YBG}+\mathrm{ZBB}},$ $\mathrm{yB}=\frac{\mathrm{YBG}}{\mathrm{XBR}+\mathrm{YBG}+\mathrm{ZBB}}$

Substituting the chromaticity coordinate value of the standard chromaticity system to solve the proportional relation a: b: c of the unknown quantities a, b and c;

the number of the red, green, and blue leds 215, 216, and 217 is determined such that the light emitted from the backlight module 21 can display predetermined red, green, blue, and other colors in cooperation with the lcd panel 20. Therefore, the chromaticity coordinate of the 1931CIE-XYZ standard chromaticity system corresponding to the preset color and the formula (3) are substituted into the formula (4) to obtain a homogeneous linear equation set related to a, B and C, and because the homogeneous linear equation set has no unique solution, only the proportional relation of a, B and C can be determined, namely a: B: C is A: B: C. Therefore, the number of a, B and C satisfying the condition of a: B: C: a: B: C can achieve the purpose of displaying ideal red, green, blue and other colors by matching with the liquid crystal display panel 20.

Sixthly, determining a, b and c;

a, B, C obtained above may not be an integer, and a, B, C are the numbers of the red, green, blue leds 215, 216, 217 in actual situation, i.e. integers, so the a, B, C can select a set of integers within a certain precision, and the ratio a: B: C is the closest to a: B: C. And because the integers a, B and C which are closest to A, B and C may be integers with large quantity, which are not in accordance with the actual situation, the requirement of the actual situation can be met by selecting a group of integers a, B and C which are small in quantity and are closer to A, B and C.

Through the above steps, the determination of the numbers of the red, green and blue leds 215, 216 and 217 in the backlight module 21 is completed.

In addition, considering that the similar numbers of red, green and blue light emitting diodes 215, 216 and 217 are arranged in a mixed manner according to a certain rule, good light mixing uniformity can be obtained, so when the red, green and blue light emitting diodes 215, 216 and 217 are selected, the red, green and blue light emitting diodes 215, 216 and 217 with proper frequency spectrums can be selected, and the number ratio A: B: C of the red, green and blue light emitting diodes 215, 216 and 217 determined by the steps is as close to 1: 2: 1 as possible, so that the arranged red, green and blue light emitting diodes 215, 216 and 217 can realize uniform light mixing.

Compared with the prior art, the liquid crystal display device 2 of the invention adopts the first port to provide a voltage to supply power to the light source array, and correspondingly designs the number of the red, green and blue light emitting diodes, thereby realizing the effect of needing three ports to work in the prior art and reducing the cost. And the circuit only outputs one voltage, so that the structure of the power supply circuit is simple.

Fig. 6 is a schematic structural diagram of a backlight module of a liquid crystal display device according to a second embodiment of the invention. The backlight module 31 is different from the backlight module 21 of the liquid crystal display device 2 of the first embodiment in that: the backlight module 31 further includes a trimming array 313. The power supply circuit 311 further includes a second port 310 for supplying power to the trimming array 313. The trimming array 313 includes a red LED 318 and a green LED 319. The red led 318 and the green led 319 are connected in series and connected to the second port 310.

Due to the principle of the first embodiment, the numbers a, B, C of the red, green, blue leds of the light source array 314 are necessarily integers, and the ratio of the numbers a, B, C to the calculated a: B: C may not be completely equal. The voltage provided by the second port 310 is lower than the voltage provided by the first port 312, which allows the red leds 318 and the green leds 319 of the trim array 313 to operate at lower power, such that the red leds 318 and the green leds 319 are actually less powerful than a single red led and a single green led in the light source array 314.

Compared with the first embodiment, the liquid crystal display device of the present embodiment employs the fine adjustment array 313 and the second port 310, and performs fine adjustment in accordance with the light source array 314 on the basis of the existing light source array 314, so that the chromaticity coordinates of the display light are closer to the ideal value.

However, the liquid crystal display device of the present invention is not limited to the first and second embodiments, wherein the trimming array includes at least one of red, green, and blue light emitting diodes. The output voltage of the second port may also be higher than the voltage of the first port.

Claims (9)

1. A liquid crystal display device comprises a liquid crystal display panel and a backlight module, wherein the backlight module and the liquid crystal display panel are arranged in a laminated manner; the backlight module comprises a circuit and a light source array, and is characterized in that: the circuit comprises a first port for supplying power to the light source array, the light source array comprises a plurality of red light-emitting diodes, a plurality of green light-emitting diodes and a plurality of blue light-emitting diodes which are connected in series, the number of the red, green and blue light-emitting diodes is a, b and c respectively, the backlight module can be matched with the liquid crystal display device to display preset color coordinates, and the backlight module can be matched with the liquid crystal display device to display preset color coordinatesa. The b and c values can be determined by the chromaticity coordinates of the predetermined color coordinates, the spectrum of the red light emitting diode is S (R), the spectrum of the green light emitting diode is S (G), the spectrum of the blue light emitting diode is S (B), and the transmission spectrum of the liquid crystal display panel in the red display state is tau_R(λ) a transmission spectrum in a green-displaying state is τ_G(λ) a transmission spectrum in a state of displaying blue is τ_B(λ), the chromaticity coordinate of red displayed by the liquid crystal display panel is a predetermined value (xR, yR), the chromaticity coordinate of green displayed by the liquid crystal display panel is a predetermined value (xG, yG), the chromaticity coordinate of blue displayed by the liquid crystal display panel is a predetermined value (xB, yB),

for spectral tristimulus values, a, B, C are unknowns, by solving the system of equations:

<math><mrow><mfenced open='{' close=''><mtable><mtr><mtd><mi>Xin</mi><mo>=</mo><mi>S</mi><mrow><mo>(</mo><mi>n</mi><mo>)</mo></mrow><msub><mi>&tau;</mi><mi>n</mi></msub><mrow><mo>(</mo><mi>&lambda;</mi><mo>)</mo></mrow><mover><mi>x</mi><mo>&OverBar;</mo></mover><mrow><mo>(</mo><mi>&lambda;</mi><mo>)</mo></mrow></mtd></mtr><mtr><mtd><mi>Yin</mi><mo>=</mo><mi>S</mi><mrow><mo>(</mo><mi>n</mi><mo>)</mo></mrow><msub><mi>&tau;</mi><mi>n</mi></msub><mrow><mo>(</mo><mi>&lambda;</mi><mo>)</mo></mrow><mover><mi>y</mi><mo>&OverBar;</mo></mover><mrow><mo>(</mo><mi>&lambda;</mi><mo>)</mo></mrow></mtd></mtr><mtr><mtd><mi>Zin</mi><mo>=</mo><mi>S</mi><mrow><mo>(</mo><mi>n</mi><mo>)</mo></mrow><msub><mi>&tau;</mi><mi>n</mi></msub><mrow><mo>(</mo><mi>&lambda;</mi><mo>)</mo></mrow><mover><mi>z</mi><mo>&OverBar;</mo></mover><mrow><mo>(</mo><mi>&lambda;</mi><mo>)</mo></mrow></mtd></mtr></mtable></mfenced><mo>,</mo><mi>i</mi><mo>=</mo><mn>1,2,3</mn><mo>,</mo><mi>n</mi><mo>=</mo><mi>R</mi><mo>,</mo><mi>G</mi><mo>,</mo><mi>B</mi></mrow></math>

<math><mrow><mi>XRR</mi><mo>=</mo><mrow><mo>(</mo><mi>A</mi><mo>,</mo><mi>B</mi><mo>,</mo><mi>C</mi><mo>)</mo></mrow><mo>&CenterDot;</mo><mfenced open='[' close=']'><mtable><mtr><mtd><mi>X</mi><mn>1</mn><mi>R</mi></mtd></mtr><mtr><mtd><mi>X</mi><mn>2</mn><mi>R</mi></mtd></mtr><mtr><mtd><mi>X</mi><mn>3</mn><mi>R</mi></mtd></mtr></mtable></mfenced></mrow></math> <math><mrow><mi>XGR</mi><mo>=</mo><mrow><mo>(</mo><mi>A</mi><mo>,</mo><mi>B</mi><mo>,</mo><mi>C</mi><mo>)</mo></mrow><mo>&CenterDot;</mo><mfenced open='[' close=']'><mtable><mtr><mtd><mi>X</mi><mn>1</mn><mi>G</mi></mtd></mtr><mtr><mtd><mi>X</mi><mn>2</mn><mi>G</mi></mtd></mtr><mtr><mtd><mi>X</mi><mn>3</mn><mi>G</mi></mtd></mtr></mtable></mfenced></mrow></math> <math><mrow><mi>XBR</mi><mo>=</mo><mrow><mo>(</mo><mi>A</mi><mo>,</mo><mi>B</mi><mo>,</mo><mi>C</mi><mo>)</mo></mrow><mo>&CenterDot;</mo><mfenced open='[' close=']'><mtable><mtr><mtd><mi>X</mi><mn>1</mn><mi>B</mi></mtd></mtr><mtr><mtd><mi>X</mi><mn>2</mn><mi>B</mi></mtd></mtr><mtr><mtd><mi>X</mi><mn>3</mn><mi>B</mi></mtd></mtr></mtable></mfenced></mrow></math>

<math><mrow><mi>YRG</mi><mo>=</mo><mrow><mo>(</mo><mi>A</mi><mo>,</mo><mi>B</mi><mo>,</mo><mi>C</mi><mo>)</mo></mrow><mo>&CenterDot;</mo><mfenced open='[' close=']'><mtable><mtr><mtd><mi>Y</mi><mn>1</mn><mi>R</mi></mtd></mtr><mtr><mtd><mi>Y</mi><mn>2</mn><mi>R</mi></mtd></mtr><mtr><mtd><mi>Y</mi><mn>3</mn><mi>R</mi></mtd></mtr></mtable></mfenced></mrow></math> <math><mrow><mi>YGG</mi><mo>=</mo><mrow><mo>(</mo><mi>A</mi><mo>,</mo><mi>B</mi><mo>,</mo><mi>C</mi><mo>)</mo></mrow><mo>&CenterDot;</mo><mfenced open='[' close=']'><mtable><mtr><mtd><mi>Y</mi><mn>1</mn><mi>G</mi></mtd></mtr><mtr><mtd><mi>Y</mi><mn>2</mn><mi>G</mi></mtd></mtr><mtr><mtd><mi>Y</mi><mn>3</mn><mi>G</mi></mtd></mtr></mtable></mfenced></mrow></math> <math><mrow><mi>YBG</mi><mo>=</mo><mrow><mo>(</mo><mi>A</mi><mo>,</mo><mi>B</mi><mo>,</mo><mi>C</mi><mo>)</mo></mrow><mo>&CenterDot;</mo><mfenced open='[' close=']'><mtable><mtr><mtd><mi>Y</mi><mn>1</mn><mi>B</mi></mtd></mtr><mtr><mtd><mi>Y</mi><mn>2</mn><mi>B</mi></mtd></mtr><mtr><mtd><mi>Y</mi><mn>3</mn><mi>B</mi></mtd></mtr></mtable></mfenced></mrow></math>

<math><mrow><mi>ZRB</mi><mo>=</mo><mrow><mo>(</mo><mi>A</mi><mo>,</mo><mi>B</mi><mo>,</mo><mi>C</mi><mo>)</mo></mrow><mo>&CenterDot;</mo><mfenced open='[' close=']'><mtable><mtr><mtd><mi>Z</mi><mn>1</mn><mi>R</mi></mtd></mtr><mtr><mtd><mi>Z</mi><mn>2</mn><mi>R</mi></mtd></mtr><mtr><mtd><mi>Z</mi><mn>3</mn><mi>R</mi></mtd></mtr></mtable></mfenced></mrow></math> <math><mrow><mi>ZGB</mi><mo>=</mo><mrow><mo>(</mo><mi>A</mi><mo>,</mo><mi>B</mi><mo>,</mo><mi>C</mi><mo>)</mo></mrow><mo>&CenterDot;</mo><mfenced open='[' close=']'><mtable><mtr><mtd><mi>Z</mi><mn>1</mn><mi>G</mi></mtd></mtr><mtr><mtd><mi>Z</mi><mn>2</mn><mi>G</mi></mtd></mtr><mtr><mtd><mi>Z</mi><mn>3</mn><mi>G</mi></mtd></mtr></mtable></mfenced></mrow></math> <math><mrow><mi>ZBB</mi><mo>=</mo><mrow><mo>(</mo><mi>A</mi><mo>,</mo><mi>B</mi><mo>,</mo><mi>C</mi><mo>)</mo></mrow><mo>&CenterDot;</mo><mfenced open='[' close=']'><mtable><mtr><mtd><mi>Z</mi><mn>1</mn><mi>B</mi></mtd></mtr><mtr><mtd><mi>Z</mi><mn>2</mn><mi>B</mi></mtd></mtr><mtr><mtd><mi>Z</mi><mn>3</mn><mi>B</mi></mtd></mtr></mtable></mfenced></mrow></math>

$\mathrm{xR}=\frac{\mathrm{XRR}}{\mathrm{XRR}+\mathrm{YRG}+\mathrm{ZRB}},$ $\mathrm{yR}=\frac{\mathrm{YRG}}{\mathrm{XRR}+\mathrm{YRG}+\mathrm{ZRB}}$

$\mathrm{xG}=\frac{\mathrm{XGR}}{\mathrm{XGR}+\mathrm{YGG}+\mathrm{ZGB}},$ $\mathrm{yG}=\frac{\mathrm{YGG}}{\mathrm{XGR}+\mathrm{YGG}+\mathrm{ZGB}}$

$\mathrm{xB}=\frac{\mathrm{XBR}}{\mathrm{XBR}+\mathrm{YBG}+\mathrm{ZBB}},$ $\mathrm{yB}=\frac{\mathrm{YBG}}{\mathrm{XBR}+\mathrm{YBG}+\mathrm{ZBB}}$

if the ratio of A to B to C is determined, a, B and C are integer solutions satisfying the ratio of A to B to C within an allowable error range.

2. The liquid crystal display device according to claim 1, wherein: the circuit further includes a trim array including at least one of red, green, and blue light emitting diodes and a second port for powering the trim array.

3. The liquid crystal display device according to claim 1, wherein: the spectral tristimulus values and the chromaticity coordinates are those in the 1931CIE-XYZ standard chromaticity system.

4. The liquid crystal display device according to claim 1, wherein: the values of the spectra of the red, green and blue LEDs are adjusted so that A: B: C, as determined by the system of equations, is equal to 1: 2: 1.

5. The liquid crystal display device according to claim 1, wherein: the LCD panel is a multi-layer structure, and the transmission spectrum is the product of the transmission spectra of the layers.

6. The liquid crystal display device according to claim 5, wherein: the multilayer structure of the liquid crystal display panel comprises a color filter layer, wherein the color filter layer comprises a plurality of transmission frequency spectrums tau_1RRed filter unit of (lambda), multiple penetration spectrum tau_1G(lambda) a green filter element and a plurality of transmission spectra tau_1B(lambda) a blue filter unit, the product of the transmission spectra of the layers except the color filter layer in the multilayer structure is pi tau_i(lambda) of

τ_R(λ)＝τ_1R(λ)∏τ_i(λ)

τ_G(λ)＝τ_1G(λ)∏τ_i(λ)

τ_B(λ)＝τ_1B(λ)∏τ_i(λ)。

7. The liquid crystal display device according to claim 6, wherein: the multilayer structure also comprises a first polaroid, a second polaroid, a liquid crystal layer, a first alignment layer and a second alignment layer.

8. The liquid crystal display device according to claim 7, wherein: the multi-layer structure further comprises a common electrode layer and a pixel electrode layer.

9. The liquid crystal display device according to claim 2, wherein: the voltage of the second port is less than the voltage of the first port.

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