TWI386726B - Liquid crystal display and lighting method - Google Patents

Description

Liquid crystal display and light emitting method

The present invention relates to a liquid crystal display and a light emitting method, and more particularly to a liquid crystal display capable of emitting green light and a light emitting method.

With the development of display technology, the application of liquid crystal display devices is becoming more and more popular. A liquid crystal display device usually uses a backlight and a color filter to cooperate with each other to display a full-color picture. The backlight can be a Cold Cathode Fluorescent Lamp (CCFL) or a Light Emitting Diode (LED). Because the light-emitting diode has the advantages of small size, low pollution and power saving, the light-emitting diode is favored by the industry.

A light-emitting diode is used as a backlight of a liquid crystal display device as an example. The color light emitted by the light-emitting diode, for example, white light, is changed by a color filter to change the light-emitting spectrum thereof, so that the liquid crystal display device can display pictures of different colors. Therefore, the color performance of the liquid crystal display device often depends on the light-emitting spectrum of the light-emitting diode and the transmission spectrum of the color filter.

However, under the consideration of low cost, when the existing low-cost light-emitting diode is matched with the color filter, the green light emitted by the liquid crystal display device tends to have insufficient saturation, so that the overall color performance of the liquid crystal display device is achieved. Not good. Therefore, how to improve the color performance of the liquid crystal display device by selecting appropriate light-emitting diodes and color filters under low cost considerations is one of the projects of the industry.

The invention relates to a liquid crystal display and a light-emitting method, which enhance the saturation of green light by the interaction of white light and color filter, so that the liquid crystal display according to the invention can have good color performance.

According to an embodiment of the present invention, a liquid crystal display including a backlight and a liquid crystal display panel is provided. The backlight is used to emit white light. The normalized luminescence spectrum of white light has a first peak and a second peak. The first peak is substantially equal to one. The wavelength corresponding to the first peak is less than the wavelength corresponding to the second peak, and the half-height of the second peak is less than 100 nm. The liquid crystal display panel is disposed on one side of the backlight and has a color filter. One part of the color filter is used to filter white light and emit green light. The transmission spectrum of the color filter for emitting green light is intersected with the normalized illumination spectrum of white light at the first intersection point and the second intersection point. The difference between the wavelength corresponding to the first intersection point and the wavelength corresponding to the second intersection point is less than 127 nm.

According to another embodiment of the present invention, a method of illuminating is provided, comprising the following steps. First, white light is produced. The normalized luminescence spectrum of white light has a first peak and a second peak. The first peak is substantially equal to one. The wavelength corresponding to the first peak is less than the wavelength corresponding to the second peak, and the half-height of the second peak is less than 100 nm. Next, a portion of the color filter of the liquid crystal display panel is used to partially filter the white light and emit green light. The transmission spectrum of the color filter that emits the green light intersects the normalized illumination spectrum of the white light at the first intersection point and the second intersection point. The difference between the wavelength corresponding to the first intersection point and the wavelength corresponding to the second intersection point is less than 127 Nai Meter.

In order to make the above-mentioned contents of the present invention more comprehensible, the preferred embodiments are described below, and the detailed description is as follows:

A liquid crystal display according to an embodiment of the present invention includes a backlight and a liquid crystal display panel. The backlight is used to emit white light. The normalized luminescence spectrum of white light has a first peak and a second peak. The first peak is substantially equal to one. The wavelength corresponding to the first peak is less than the wavelength corresponding to the second peak, and the half-height of the second peak is less than 100 nm. Here, the full width at half maximum means the difference between the two wavelengths corresponding to the waveform having the second peak at the second peak of 1/2 thereof. The liquid crystal display panel is disposed on one side of the backlight and has a color filter. One part of the color filter is used to filter white light and emit green light. The transmission spectrum of the filter for emitting green light intersects the white light normalized illumination spectrum at the first intersection point and the second intersection point. The difference between the wavelength corresponding to the first intersection point and the wavelength corresponding to the second intersection point is less than 127 nm.

Please refer to FIG. 1 , which is a schematic diagram of a liquid crystal display according to a preferred embodiment of the present invention. The liquid crystal display 200 includes a backlight 210 and a liquid crystal display panel 230. The liquid crystal display panel 230 is disposed on one side of the backlight 210. The backlight 210 includes, for example, a plurality of light emitting diodes 211 for emitting white light W.

The liquid crystal display panel 230 has an upper substrate 230a, a lower substrate 230b, an insulating layer 232, alignment films 233a and 233b, a pixel electrode 234, and a protective layer. 235, a liquid crystal layer 236, a common electrode 237, a thin film transistor 239, and a color filter 231. The gate (not labeled) of the thin film transistor 239, the insulating layer 232, the active layer (not labeled) of the thin film electrode body 239, the drain (not labeled) and the source (not labeled), the protective layer 235, and the pixel electrode 234 The alignment film 233b is sequentially disposed on the lower substrate 233b. The pixel electrode 234 is electrically coupled to the source of the thin film transistor 239. The color filter 231, the common electrode 237, and the alignment film 233a are sequentially disposed on the upper substrate 230a. The liquid crystal layer 236 is sealed between the upper substrate 230a and the lower substrate 230b.

In the present embodiment, the color filter 231 has a black matrix BM, a red filter layer 231R, a blue filter layer 231B, and a green filter layer 231G. When the white light W emitted from the light-emitting diode 211 of the backlight 210 passes through the liquid crystal display panel 230, the red filter layer 231R, the blue filter layer 231B, and the green filter layer 231G filter the white light W and emit red light respectively. , blue light B and green light G.

Please refer to FIG. 2 at the same time, which shows a schematic diagram of the illumination spectrum of the backlight and the penetration spectrum of the green filter layer in FIG. 1 . The left ordinate, the right ordinate, and the abscissa in Fig. 2 represent the normalized light intensity, unit light intensity (cd/unit), and wavelength (nm), respectively. The values y1 to y12 on the right ordinate indicate the light intensity of y1 to y12 units, respectively. The normalized luminescence spectrum of white light W is indicated by the dashed line L1 and corresponds to the left ordinate. The color filter 231 for emitting a portion of the green light G, that is, the green filter layer 231G, has a penetration spectrum indicated by a solid line L2 and corresponds to a right ordinate.

The white light W of the present embodiment is generated, for example, by emitting blue light from a plurality of blue light-emitting diodes to excite the fluorescent material disposed thereon. As shown in Figure 2 As shown, the normalized luminescence spectrum L1 of white light W has a first peak P1 and a second peak P2, and the first peak P1 is substantially equal to one. The wavelength wP1 corresponding to the first peak P1 is smaller than the wavelength wP2 corresponding to the second peak P2, and the half-height width FWHM of the second peak P2 is less than 100 nm.

The color filter 231 for emitting a portion of the green light G, that is, the green filter layer 231G, the normalized light-emitting spectrum L1 of the penetration spectrum L2 and the white light W intersects at the first intersection point I1 and the second Intersection point I2. In the present embodiment, the difference D between the wavelength wI1 corresponding to the first intersection point I1 and the wavelength wI2 corresponding to the second intersection point I2 is less than 127 nm. As a result, the color performance of the green light G has better saturation.

Compared with the case where the penetration spectrum of the color filter that does not emit green light is selected and the distance between the two intersections of the white light normalized emission spectrum, the green light G emitted by the liquid crystal display 200 of the present embodiment has The saturation is better, and the deviation of the color of the green light G can be avoided, so that the liquid crystal display 200 has good color performance.

In the embodiment, the backlight 210 in FIG. 1 is described by taking a direct type backlight as an example, but is not limited thereto. It should be apparent to those skilled in the art that any backlight that can provide white light to the liquid crystal display panel 230, such as an edge-lit backlight, can be used in this embodiment.

The liquid crystal display 200 of the present embodiment will be further described below. Preferably, the first peak P1 of the normalized light-emitting spectrum L1 of the white light W as shown in FIG. 2 is larger than the second peak P2, and the wavelength wP2 corresponding to the second peak P2 is greater than 500 nm. Furthermore, in order to have more saturation The green light is used to enhance the color performance of the liquid crystal display 200. The difference D between the wavelength wI1 and the wavelength wI2 in this embodiment may range from 90 to 127 nm, but is not limited thereto. As long as the normalized light spectrum of the white light and the color filter for emitting the green light are coordinated, the difference between the wavelength corresponding to the first intersection and the wavelength corresponding to the second intersection is less than 127 nm can be applied to this embodiment.

As shown in FIG. 1 , the color filter 231 of the present embodiment includes a red filter layer 231R, a blue filter layer 231B, and a green filter layer 231G, and the green filter layer 231G is used to filter the white light W to emit Green light G. However, this embodiment is not limited to the use of a color filter having a red filter layer, a blue filter layer, and a green filter layer. A color filter having other white light that can filter white light to emit two or more colors of light to mix green light can also be applied to the present embodiment. The following will be illustrated. Of course, it will be apparent to those of ordinary skill in the art that color filters that utilize any amount of color light to mix green light can be used in this embodiment.

Please refer to FIG. 3, which illustrates a schematic diagram of another liquid crystal display. The color filter 231' of the liquid crystal display 200' includes, for example, a first color filter layer 231a', a second color filter layer 231b', a red filter layer 231R', and a blue filter layer 231B'. The color of the first color filter layer 231a' is, for example, yellow, and the color of the second color filter layer 231b' is, for example, cyan. The first color filter layer 231a' and the second color filter layer 231b' filter the white light W to emit green light G', and the red filter layer 231R' and the blue filter layer 231B' filter the white light W to respectively emit Red light R' and blue light B'.

First color filter layer 231a' and second color filter layer 231b' The normalized illuminating spectrum of the effective penetration spectrum and the white light W intersect at the first intersection point and the second intersection point such that the difference between the wavelength corresponding to the first intersection point and the wavelength corresponding to the second intersection point is less than 127 nm. Therefore, the liquid crystal display 200' can also be used to avoid a deviation in the color of the green light G'. Thus, the green light G' of the liquid crystal display 200' has good saturation, so that the color performance of the liquid crystal display 200' is improved. Of course, the color of the first color filter layer and the color of the second color filter layer are merely examples, and are not intended to limit the present invention.

Referring to FIG. 4, a flow chart of a method of illuminating according to a preferred embodiment of the present invention is shown. The light-emitting method in Fig. 4 is explained using the liquid crystal display 200 in Fig. 1 . However, it should be understood by those of ordinary skill in the art that the method of illuminating is not limited to the order of steps and steps in FIG. 4, and is not limited to being performed only by the liquid crystal display 200 of FIG.

As shown in Fig. 4, the light-emitting method includes the following steps. First, in step 501, the white light W is generated by the backlight 210 in FIG. As shown in FIG. 2, the normalized light-emission spectrum L1 of the white light W has a first peak P1 and a second peak P2, and the first peak P1 is substantially equal to 1. The wavelength wP1 corresponding to the first peak P1 is smaller than the wavelength wP2 corresponding to the second peak P2, and the half-height width FWHM of the second peak P2 is less than 100 nm.

Next, in step 503, the portion of the color filter 231 of the liquid crystal display panel 230 in Fig. 1, for example, the green filter layer 231G thereof, is used to filter the white light W and emit green light G. Glow green light G The normalized light-emitting spectrum L1 of the green filter layer 231G intersects the normalized light-emitting spectrum L1 of the white light W at the first intersection point I1 and the second intersection point I2. Since the difference between the wavelength wI1 corresponding to the first intersection point I1 and the wavelength wI2 corresponding to the second intersection point I2 is less than 127 nm, the green light G has good saturation.

Of course, the light-emitting method in FIG. 4 can also perform the steps using the liquid crystal display 200' in FIG. 3, and the step 503 in FIG. 4 utilizes the color filter 231' of the liquid crystal display panel 230'. The first color filter layer 231a' and the second color filter layer 231b' filter the white light W to emit green light G'. The equivalent transmission spectrum of the first color filter layer 231a' and the second color filter layer 231b' intersects with the normalized luminescence spectrum of the white light W at the first intersection point and the second intersection point, so that the corresponding The difference between the wavelength of one intersection point and the wavelength corresponding to the second intersection point is less than 127 nm. Thus, the green light G' has a better saturation. Here, the color of the first color filter layer 231a' is, for example, yellow, and the color of the second color filter layer 231b' is, for example, cyan.

In addition, preferably, the first peak P1 of the normalized luminescence spectrum L1 of the white light W formed in step 501 is greater than the second peak P2, and the wavelength wP2 corresponding to the second peak P2 is greater than 500 nm. Furthermore, in this embodiment, if the saturation of the green light G in FIG. 1 is further improved, the difference between the wavelength corresponding to the first intersection point and the wavelength corresponding to the second intersection point may also be defined. For example, the range in which the difference between the wavelengths corresponding to the two intersection points is selected is in the range of 90 to 127 nm. However, the wavelength corresponding to the first intersection point and the wave corresponding to the second intersection point The range of long differences is not limited to this.

The liquid crystal display and the light-emitting method disclosed in the above embodiments of the present invention, which modulate the light-emitting spectrum of the backlight and the transmission spectrum of the color filter for emitting the green light, so that the light-emitting spectrum of the backlight and the color of the portion The difference between the wavelengths of the two intersections of the filter's transmission spectrum is less than 127 nm. Thus, the green light emitted according to the present embodiment has good saturation, so that the liquid crystal display of the embodiment can have good color performance.

In conclusion, the present invention has been disclosed in the above preferred embodiments, and is not intended to limit the present invention. A person skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

200, 200'‧‧‧ liquid crystal display

210‧‧‧Backlight

230, 230'‧‧‧ LCD panel

230a‧‧‧Upper substrate

230b‧‧‧lower substrate

231, 231'‧‧‧ color filters

231a’‧‧‧First color filter

231B, 231B'‧‧‧ blue filter layer

231b’‧‧‧Second color filter

231G‧‧‧Green filter layer

231R, 231R'‧‧‧ red filter layer

232‧‧‧Insulation

233a, 233b‧‧‧ alignment film

234‧‧‧ pixel electrodes

235‧‧ ‧ protective layer

236‧‧‧Liquid layer

237‧‧‧Common electrode

239‧‧‧film transistor

B, B’‧‧‧Blue light

D‧‧‧Difference

FWHM‧‧‧Half width

G, G’‧‧‧ Green Light

11‧‧‧First meeting point

12‧‧‧Second meeting point

The normalized luminescence spectrum of L1‧‧‧ white light

L2‧‧‧Green filter layer penetration spectrum

P1‧‧‧ first peak

P2‧‧‧ second peak

R, R’‧‧‧ red light

W‧‧‧White light

wI1, wI2, wP1, wP2‧‧‧ wavelength

FIG. 1 is a schematic view of a liquid crystal display according to a preferred embodiment of the present invention.

FIG. 2 is a schematic diagram showing the light-emitting spectrum of the backlight and the penetration spectrum of the green filter layer in FIG. 1 .

FIG. 3 is a schematic view showing another liquid crystal display.

4 is a flow chart showing a method of illuminating according to a preferred embodiment of the present invention.

D‧‧‧Difference

FWHM‧‧‧Half width

I1‧‧‧First meeting point

I2‧‧‧Second meeting point

The normalized luminescence spectrum of L1‧‧‧ white light

L2‧‧‧Green filter layer penetration spectrum

P1‧‧‧ first peak

P2‧‧‧ second peak

wI1, wI2, wP1, wP2‧‧‧ wavelength

Claims (14)

A liquid crystal display comprising: a backlight for emitting a white light, the normalized light spectrum of the white light having a first peak and a second peak, the first peak is substantially equal to 1, corresponding to The wavelength of the first peak is smaller than the wavelength corresponding to the second peak, and the half width of the second peak is less than 100 nm; and a liquid crystal display panel is disposed on one side of the backlight and has a color a filter, one of the color filters is configured to filter the white light and emit a green light, and the transmission spectrum of the color filter for emitting the portion of the green light is normalized to the white light The illuminating spectrum intersects at a first intersection point and a second intersection point, and a difference between a wavelength corresponding to the first intersection point and a wavelength corresponding to the second intersection point is less than 127 nm. The liquid crystal display of claim 1, wherein the color filter comprises a green filter layer, the penetration spectrum of the green filter layer intersects with the normalized illumination spectrum of the white light at the first The intersection point and the second intersection point, the green filter layer filters the white light to emit the green light. The liquid crystal display of claim 1, wherein the color filter comprises a first color filter layer and a second color filter layer, the first color filter layer and the second color filter layer. The equivalent penetration spectrum of the layer intersects the normalized illumination spectrum of the white light at the first intersection point and the second intersection point, and the first color filter layer and the second color filter layer filter the white light To emit the green light. The liquid crystal display of claim 3, wherein the color of the first color filter layer is substantially yellow, and the color of the second color filter layer is substantially cyan. The liquid crystal display of claim 1, wherein a range corresponding to a difference between a wavelength of the first intersection point and a wavelength corresponding to the second intersection point is 90 to 127 nm. The liquid crystal display of claim 1, wherein the wavelength corresponding to the second peak is greater than 500 nm. The liquid crystal display of claim 1, wherein the first peak is greater than the two peaks. A method of illuminating, comprising: (a) generating a white light, the normalized illuminating spectrum of the white light having a first peak and a second peak, the first peak being substantially equal to 1, corresponding to the first peak The wavelength system is smaller than a wavelength corresponding to the second peak, and a half-height width of the second peak is less than 100 nm; and (b) partially filtering the white light and emitting a green color using one of the color filters of one of the liquid crystal display panels Light, the transmission spectrum of the color filter that emits the portion of the green light intersects with the normalized illumination spectrum of the white light at a first intersection point and a second intersection point, corresponding to the first intersection point The difference between the wavelength and the wavelength corresponding to the second intersection is less than 127 nm. The illuminating method of claim 8, wherein the color filter comprises a green filter layer, and a penetration spectrum of the green filter layer intersects with a normalized luminescence spectrum of the white light. a meeting point and In the second intersection, step (b) uses the green filter layer to filter the white light to emit the green light. The illuminating method of claim 8, wherein the color filter comprises a first color filter layer and a second color filter layer, the first color filter layer and the second color filter layer An equivalent transmission spectrum of the layer intersects the normalized illumination spectrum of the white light at the first intersection point and the second intersection point, and step (b) utilizes the first color filter layer and the second color filter layer The light layer filters the white light to emit the green light. The method of illuminating according to claim 10, wherein the color of the first color filter layer is substantially yellow, and the color of the second color filter layer is substantially cyan. The illuminating method according to claim 8, wherein a range corresponding to a difference between a wavelength of the first intersection point and a wavelength corresponding to the second intersection point is 90 to 127 nm. The method of illuminating according to claim 8, wherein the wavelength corresponding to the second peak is greater than 500 nm. The illuminating method of claim 8, wherein the first peak is greater than the two peaks.