TWI599825B - Backlight module having design for improving blue light hazard and display module utilized thereof - Google Patents

Description

Backlight module with blue light damage improvement design and display module using same

The present invention relates to a backlight module and a display module using the same; in particular, the present invention relates to a backlight module with a blue light damage improvement design and a display module using the same.

With the advancement of display technology, there are many products that can provide high-quality images. In the case of backlight modules, the way in which fluorescent tubes have been used as backlights has been gradually replaced by light-emitting diodes. The light-emitting diode has the advantages of high luminous efficiency and long service life, and the display with the light-emitting diode as the backlight can reduce the overall volume under the same size, thereby achieving a lightweight effect.

In terms of light emission, a commonly used light-emitting diode backlight module uses a blue light-emitting diode to generate white light by exciting blue-light phosphor powder emitted from a blue light-emitting diode chip. However, the intensity of the blue light emitted by the blue light emitting diode chip is quite high. Please refer to the schematic diagram of the backlight spectrum of the conventional backlight module of FIG. The curve 10 shown in FIG. 1 is the backlight spectrum of a conventional blue light emitting diode chip. As shown in FIG. 1, the conventional backlight module has a relatively high relative intensity between 400 nm and 500 nm (corresponding to the blue light band).

In addition, since blue light is a relatively strong visible light, its ability to penetrate the cornea is better. Strong, most of the energy absorbed by the retina after the cornea penetrates the cornea, causing photochemical damage to the retina. In recent years, studies have been pointed out that long-term exposure to high-energy bands in displays can cause discomfort and even damage to the eyes of users, such as cataracts or macular degeneration. Long-term exposure of the human eye to light in this wavelength range can cause photochemical damage to the retina. It can be seen from the above that in order to reduce the health effects of the light emitted by the backlight module, the existing display still needs to be improved.

An object of the present invention is to provide a backlight module that can reduce the damage of blue light to the eyes.

Another object of the present invention is to provide a display module that can reduce the intensity of the blue light band and maintain the optical performance of the display.

The backlight module includes a light source that produces a backlight. A backlight having a wavelength [lambda] is the spectral T argument of (λ), and is defined with a wavelength [lambda] is the indicator function F argument of (λ): F (λ) = T (λ) * B (λ), where B ( λ ) is the Blue Hazard Function. The index function F( λ ) has a first index peak between 430 nm and 490 nm and a second index peak between 495 nm and 565 nm. The ratio of the peak of the first index peak to the peak of the second index peak is between 12.1 and 15.7. By reducing the blue light intensity of the backlight, the damage of the blue light to the eyes can be reduced.

100‧‧‧ display module

110‧‧‧ display panel

120‧‧‧Backlight module

121‧‧‧Optical diaphragm

122‧‧‧Light source

124‧‧‧Light Emitting Diode Wafer

126‧‧‧Blue Fluorescent Powder

128‧‧‧Green Fluorescent Powder

130‧‧‧Red Fluorescent Powder

310,320,330‧‧‧ Curve

400,410,420,430‧‧‧ indicator function

401,411,421,431‧‧‧ first indicator peak

402,412,422,432‧‧‧second indicator peak

500, 530, 550 ‧ ‧ color range

A, B, C‧‧‧ area

W1, w2‧‧‧ half height

1 is a schematic diagram of a backlight spectrum distribution of a conventional backlight module; FIG. 2 is a schematic diagram of an embodiment of a display module of the present invention; FIG. 3 is a schematic diagram of an embodiment of a light source; 4 is a schematic diagram of a backlight spectrum distribution of a backlight module of the present invention; FIG. 5 is a schematic diagram of a blue damage function; FIG. 6 is a schematic diagram of a distribution of index functions; FIG. 7 is a half-height width diagram of an index function; Schematic diagram of the color range of the module.

The invention provides a display module with a blue light damage improvement design. The display module of the present invention is preferably a liquid crystal display, which uses a light-emitting diode chip with appropriate blue phosphor powder to reduce the intensity of blue light in the incident light of the backlight module, so as to improve the conventional display module may be generated for the human eye. s damage.

2 is a schematic diagram of an embodiment of a display module 100 of the present invention. As shown in FIG. 2 , the display module 100 includes a display panel 110 and a backlight module 120 . The backlight module 120 is disposed on one side of the display panel 110 and includes an optical film 121 and a light source 122 disposed on a side of the optical film 121 opposite to the display panel 110 to generate a backlight. 3 is a schematic view of an embodiment of a light source. As shown in FIG. 3, the light source 122 is a light emitting diode comprising a light emitting diode wafer 124. The first phosphor powder and the second phosphor powder are filled in the light emitting diode package, and the first phosphor powder and the second phosphor powder are complementary colors to form a white light backlight. For example, in the embodiment shown in FIG. 3, the blue phosphor powder 126 filled in the light source 122 is used as the first phosphor powder, and the green phosphor powder 128 and the red phosphor powder 130 are used as the second phosphor powder. The light generated by the LED wafer 124 excites the blue phosphor powder 126 and the green phosphor powder 128 and the red phosphor powder 130 to form a white backlight. In other embodiments, the blue phosphor powder may also be used as the first phosphor powder, and the yellow phosphor powder having the complementary color may be selected as the second phosphor powder. The LED chip 124 is preferably an ultraviolet light emitting diode chip, but is not limited thereto.

The backlight generated by the backlight module has a backlight spectrum distributed at different wavelengths. The backlight can be defined as the light generated by the backlight itself or the light passing through the optical film in the backlight module. Please refer to FIG. 4 for a schematic diagram of the backlight spectrum distribution of the backlight module. In Figure 4, the different curves represent the backlight spectrum of the backlight module using different light sources. Wherein, the curves 310, 320, 330 are the backlight spectrum of the light-emitting diode wafer of the present invention, and the different curves represent the different amounts of blue phosphor powder in the light-emitting diode wafer of the present invention. The backlight spectrum corresponding to the curve 310 to the curve 330 sequentially represents the decreasing content of the filled blue phosphor powder, the blue fluorescent powder luminous intensity is taken as the reference value of the curve 310, and the curve 320 blue fluorescent powder luminous intensity is reduced by 5%, the curve 330 blue light Fluorescent powder luminous intensity is reduced by 10%. As shown in FIG. 4, the relative intensity of the backlight module of the present invention at a wavelength between 400 nm and 500 nm (corresponding to the blue light band) is significantly lower than that of the conventional light source, and the first phosphor powder is adjusted by the blue phosphor powder reduction. The proportion of the second phosphor will reduce the damage of blue light to the eyes. In addition, the ratio of the first phosphor powder to the second phosphor powder can be adjusted by increasing the amount of phosphor powder of the complementary color, for example, the content of the yellow phosphor powder is increased. For the case of filling the green fluorescent powder and the red fluorescent powder as the second fluorescent powder, the content of the green fluorescent powder and the red fluorescent powder may be adjusted, or at least the green fluorescent powder content may be adopted. The way to increase the height to reduce the damage of blue light in the light source to the eyes.

In addition, according to the International Electrotechnical Commission (IEC), the safety standard for photobiosafety, IEC62471, is proposed for the influence of blue light in light sources on the human body. It proposes a blue hazard function closely related to human eye health (Blue Hazard). Function). As shown in Fig. 5, B( λ ) is a blue-damage function, and light having a wavelength range between 380 nm and 540 nm has different degrees of stimulation values for the retina. The Applicant has found that using the blue damage function as the weighting parameter of the backlight spectrum of the present invention, the backlight module of the present invention has several features, which are further described below.

Figure 6 is a schematic diagram showing the distribution of the index function. The curves in Figure 6 indicate no The index function of the backlight module is the product of the backlight spectrum and the blue damage function, thereby highlighting the backlighting of different backlight modules in the wavelength range between 380 nm and 540 nm, and the degree of stimulation to the retina. In detail, the index function is defined as a function F(λ) with one of the wavelengths λ as an independent variable, having the following relationship: F(λ)=T(λ)*B(λ), where T(λ) is the backlight spectrum, B(λ) is a blue damage function. In FIG. 6, the dotted line shows the index function 400 of the conventional blue light emitting diode chip, and the solid line shows the index function corresponding to the backlight spectrum (310, 320, 330) of the light emitting diode chip of the present invention. (410, 420, 430). As shown in FIG. 6, the relative stimulation intensity of the backlight module of the present invention in the corresponding blue light band is significantly lower than that of the conventional light source.

Further, the index function (410, 420, 430) has two peaks, wherein the index function (410, 420, 430) has a first index peak (411, 421, 431) between wavelengths 430 nm and 490 nm, which is generated by the excitation of the blue phosphor in the backlight. section. In addition, the index function (410, 420, 430) has a second index peak (412, 422, 432) between wavelengths 495 nm and 565 nm, which corresponds to the portion of the backlight that is generated by the excitation of the green phosphor. As shown in FIG. 6, the peak of the first index peak (411, 421, 431) is between 0.3 and 0.5, which is significantly lower than the peak of the first index peak 401 (close to 1) of the conventional light source, and the high energy can be reduced. The visible light is irritating to the human eye.

In addition, the backlight module of the present invention has a characteristic that the peak value of the first and second index peaks has a ratio between 12.1 and 15.7, and the intensity of the index function corresponding to the backlight is adjusted by adjusting the content of the blue phosphor powder. The proportional relationship between this range can take into account the effects of human eye protection and color performance. Referring to FIG. 7, a half-height width diagram of the index function is shown. As shown in FIG. 7, the half-height width w1 of the first index peak 401 of the conventional light source is 18 nm, and the half-height width w2 of the first index peak 431 having the lowest stimulation intensity of the light source of the present invention is 32 nm. In other words, with the indicator function 400 The half-height width is used as the lower limit value, and the half-height width of the index function 430 is taken as the upper limit value, and the light source corresponding to the range is used, and the distribution waveform covers a wide range of the wave band, and the stimulation of the human eye by the specific band is reduced. . With the backlight module of the present invention, the backlight adjustment adjusts the half-height width of the first index peak of the corresponding index function between 18 nm and 32 nm, thereby providing better protection of the human eye.

As described above, the backlight module of the present invention can provide better color performance in addition to reducing the damage of blue light to the eyes. The results of measuring the color performance are shown in Table 1: It can be seen from the data in Table 1 that the backlight module of the present invention can provide better color performance according to the color gamut standard of NTSC, and can provide color performance greater than 90% of NTSC. . Please refer to FIG. 8 for a schematic diagram of the color range. The triangular frame shown in FIG. 8 represents the color range of different backlight modules in the chromaticity coordinates defined by CIE1931. As shown in FIG. 8, the backlight of the conventional blue light emitting diode chip has a color range of 500, and the backlight of the light emitting diode chip of the present invention has a color range 530 (corresponding to the light source of the backlight spectrum 330), and the color gamut standard of the NTSC Defined as a color range of 550. As can be seen from FIG. 8, the backlight module of the present invention is retracted from the range of the region A (substantially corresponding to blue light) with respect to the conventional light source, and the range of the region B (corresponding to the green light) and the region C (corresponding to the red light). Wide distribution. In general, the backlight module of the present invention can cover the color range defined by the NTSC color gamut standard, has better color performance, and provides human eye protection without affecting the display effect, thereby reducing blue light damage to the eyes. .

The present invention has been described by the above-described related embodiments, but the above embodiments are merely examples for implementing the present invention. It must be noted that the disclosed embodiments do not limit the scope of the invention. On the contrary, modifications and equivalents of the spirit and scope of the invention are included in the scope of the invention.

100‧‧‧ display module

110‧‧‧ display panel

120‧‧‧Backlight module

121‧‧‧Optical diaphragm

122‧‧‧Light source

Claims (13)

A backlight module comprises: a light source, which generates a backlight; wherein the backlight has a spectrum T(λ) which is one of the independent variables of the wavelength λ, and defines an index function F(λ) with the wavelength λ as an independent variable. ): F(λ)=T(λ)*B(λ) where: B(λ) is a Blue Hazard Function. The index function F(λ) has a first index peak between 430 nm and 490 nm. And having a second index peak between 495 nm and 565 nm; the ratio of the peak of the first index peak to the peak of the second index peak is between 12.1 and 15.7. The backlight module of claim 1, wherein the light source comprises: a light emitting diode chip; a first phosphor powder; and a second phosphor powder; wherein the light emitting diode chip generates light to excite the light emitting diode The first phosphor and the second phosphor are formed to form the backlight. The backlight module of claim 2, wherein the first phosphor powder and the second phosphor powder are complementary colors to form a white backlight. The backlight module of claim 2, wherein the first phosphor is a blue phosphor; the second phosphor is a yellow phosphor, or a combination of a red phosphor and a green phosphor. . The backlight module of claim 1, wherein a half-height width of the first index peak is between 18 nm and 32 nm. The backlight module of claim 1, wherein the peak of the first index peak is between 0.3 and 0.5. A display module includes: a display panel; and a backlight module including a light source to generate a backlight; wherein the backlight has a spectrum T(λ) having a wavelength λ as an independent variable, and is defined by a wavelength λ One of the independent variables is the index function F(λ): F(λ)=T(λ)*B(λ) where: B(λ) is the Blue Hazard Function. The index function F(λ) is at the wavelength. There is a first index peak between 430 nm and 490 nm, and a second index peak between 495 nm and 565 nm; the ratio of the peak of the first index peak to the peak of the second index peak is between 12.1 and 15.7. The display module of claim 7, wherein the light source comprises: a light emitting diode chip; a first phosphor powder; and a second phosphor powder; wherein the light emitting diode chip generates light to excite the light The first phosphor and the second phosphor are formed to form the backlight. The display module of claim 8, wherein the first phosphor and the second phosphor are complementary colors to form a white backlight. The display module of claim 8, wherein the first phosphor is blue phosphor powder; and the second phosphor is a combination of red phosphor and green phosphor. The display module of claim 10, wherein the first index peak corresponds to a portion of the backlight that is generated by the excitation of the blue phosphor; the second index peak corresponds to the green light in the backlight The part of the light powder that is excited. The display module of claim 7, wherein the first index peak has a half-height width of 18 nm. Between 32nm. The display module of claim 7, wherein the peak of the first index peak is between 0.3 and 0.5.