Detailed Description
The light splitting film is arranged on the substrate away from the display side, and the display electrode is arranged on one side of the light splitting film close to the display side, so that the light splitting film does not influence the distribution of a driving electric field, the display quality is improved, the power consumption is reduced, and the thickness of a product is reduced.
The technical scheme of the invention is particularly suitable for display devices which can not emit light autonomously, such as: the liquid crystal display device and the electrowetting display device are characterized in that light rays for display are firstly split through the splitting film and then used for display, the light ray utilization rate is improved, and a color film is default. In order to overcome the phenomenon of light mixing, when the color filter is used in combination with a color film, the light transmittance can be greatly improved, theoretically, the light transmittance can be improved by 300%, and meanwhile, the color gamut can be improved.
The following detailed description of embodiments of the present invention will be made with reference to the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.
Referring to fig. 1 and 2, the present embodiment provides a display panel, which includes a plurality of pixel regions, each pixel region includes a plurality of sub-pixel regions for transmitting light of a specific color, and the sub-pixel regions cooperate with each other to realize color display.
The display panel comprises a first substrate 1 and a second substrate 2 which are opposite to each other, and the second substrate 2 is arranged close to the display side. The display panel further includes a display electrode for forming a driving electric field.
The second substrate 2 includes a second base 200, and the first substrate 1 includes a first base 100 and a spectroscopic film 3 disposed on the first base 100. The display electrode is located between the second substrate 200 and the spectroscopic film 3, that is, the display electrode is located on the side of the spectroscopic film 3 close to the display side, so that the thickness of the spectroscopic film 3 is prevented from being large, and the electric field distribution is prevented from being influenced, and further the display is prevented from being influenced. The light splitting film 3 is used for separating light rays of a specific color from light rays for display to irradiate a sub-pixel region transmitting the light rays of the same color, so that the light ray utilization rate is improved, and a color film is absent. In order to overcome the phenomenon of light mixing, the color filter can be combined with a color film, so that the light transmittance can be greatly improved, and meanwhile, the color gamut can be improved. Meanwhile, the light splitting film 3 is arranged on the substrate of the display panel, so that the alignment precision of the light splitting film 3 and the sub-pixel area is improved, and the thickness of the device is reduced.
Among them, the spectroscopic film 3 may be disposed on the surface of the first substrate 100 near the display side as shown in fig. 1. The light-splitting film may also be disposed on a surface of the first substrate facing away from the display side.
Further, the first substrate 1 may further include a planarization layer 10 covering a surface of the spectroscopic film 3 facing away from the first base 100 to provide a planarized surface.
As a specific embodiment, the spectroscopic film 3 is disposed on the surface of the first substrate 100 near the display side, and the surface of the spectroscopic film 3 facing away from the first substrate 100 is covered with the planarization layer 10. The refractive indexes of the flat layer 10 and the light splitting film 3 are different, and the refractive index of the whole flat layer 10 is the same, so that light splitting is facilitated, and uniform distribution of light splitting is ensured. The material of the flat layer 10 is selected from high transparent materials, and the light transmittance is more than 80%. The refractive index difference between the flattening layer 10 and the spectroscopic film 3 is larger than 0.1, and the larger the difference, the better. The refractive index of the planarization layer 10 may be larger than that of the spectroscopic film 3 or smaller than that of the spectroscopic film 3.
In this embodiment, the display electrodes (e.g., the pixel electrodes and the common electrodes of the liquid crystal display panel) of the display panel are located on one side of the spectroscopic film close to the display side, and may be specifically disposed on the second substrate, the first substrate, or both the substrates. Taking the liquid crystal display panel as an example, the pixel electrode and the common electrode may be disposed on the second substrate, or may be disposed on the first substrate, or one of the electrodes may be disposed on the first substrate and the other electrode may be disposed on the second substrate. In fig. 1 and 2, the pixel electrode 4 is disposed on the second substrate 2, and the common electrode 5 is disposed on the first substrate 1. When the spectroscopic film 3 is disposed on the surface of the first substrate 100 near the display side, the common electrode 5 is particularly disposed on the planarization layer 10 covering the spectroscopic film 3.
The technical solution of the present invention will be specifically described below by taking a liquid crystal display panel as an example.
The liquid crystal display panel further includes liquid crystal molecules 300 filled between the first substrate and the second substrate. The light for display is provided by the backlight module, and is split by the splitting film 3 to irradiate the sub-pixel area.
In this embodiment, the second substrate 2 is an array substrate, a front-end manner that the array substrate 2 is disposed near the display side is adopted, and the light-splitting film 3 is disposed on the first substrate 1, which is beneficial to realizing that the liquid crystal molecules 300, the pixel electrodes 4 and the common electrode 5 are disposed on one side of the light-splitting film 3 near the display side, so that the light-splitting film 3 does not affect the driving of the electric field to the liquid crystal molecules.
For the thin film transistor array substrate, the array substrate 2 further includes a thin film transistor 6 located in each sub-pixel region, the pixel electrode 4 is electrically connected to a drain electrode 7 of the thin film transistor 6, and the thin film transistor 6 is used as a driving element to transmit pixel voltage to the pixel electrode 4. The thin film transistor has the advantages of small volume, low power consumption, simple control and the like.
Further, the spectroscopic film 3 may be disposed on a surface of the first substrate 1 near the display side, and a surface of the spectroscopic film 3 facing away from the first base 100 is covered with the planarization layer 10 to provide a planarized surface. The refractive indexes of the flat layer 10 and the light splitting film 3 are different, and the refractive index of the whole flat layer 10 is the same, so that light splitting is facilitated, and uniform distribution of light splitting is ensured.
The liquid crystal display panel may be a lateral electric field type or a longitudinal electric field type. For the lateral electric field type, pixel electrodes and common electrodes are disposed on the array substrate 2 on a surface of the second substrate 200 facing away from the display side for forming an electric field for driving the liquid crystal molecules to deflect. For the longitudinal electric field type, the pixel electrode 4 is disposed on the array substrate 2 on a surface of the second substrate 200 facing away from the display side, and the common electrode 5 is disposed on a surface of the planarization layer 10 near the display side, as shown in fig. 1 and 2.
In order to realize color display, the liquid crystal display panel further includes a filter layer 8 located in each sub-pixel region, and the filter layer 8 transmits light of a specific color. In the prior art, there are various color combinations for realizing color display, and most commonly, color display is realized by using three primary colors R, G, B. That is, each pixel region includes a sub-pixel region R, a sub-pixel region G, and a sub-pixel region B. Accordingly, the purpose of the light splitting film 3 is to separate red light, blue light and green light from light to irradiate the sub-pixel regions of corresponding colors, thereby achieving the purpose of improving the light transmittance and color gamut.
In this embodiment, the filter layer 8 is formed on the array substrate 2, so that the problem of alignment deviation is overcome, and high resolution is facilitated. Then, when the common electrode 5 is disposed on the first substrate 1, the first substrate 1 specifically includes: the light-splitting device includes a first substrate 100, a light-splitting film 3 disposed on the first substrate 100, and a planarization layer 10 covering a surface of the light-splitting film 3 facing away from the first substrate 100, and a common electrode 5 is disposed on a surface of the planarization layer 10 facing away from the light-splitting film 3.
Taking the bottom gate type thin film transistor array substrate as an example, the array substrate 2 includes a plurality of sub-pixel regions, and each sub-pixel region specifically includes:
a black matrix 9 disposed on the second substrate 200 to define a plurality of sub-pixel regions;
gate lines 20 and data lines (not shown) disposed on the black matrix 9;
a thin film transistor 6 disposed on the black matrix 9, including a gate electrode, a gate insulating layer 201 covering the gate electrode, an active layer disposed on the gate insulating layer 201, a source electrode and a drain electrode 7, the source electrode and the drain electrode 7 may overlap the active layer, the active layer may be a metal oxide semiconductor or a silicon semiconductor, the gate electrode, the source electrode and the drain electrode 7 may be made of Cu, Al, Ag, Mo, Cr, Nd, Ni, Mn, Ti, Ta, W, and other metals and alloys thereof, the gate insulating layer 201 may be made of silicon nitride, silicon oxide, or silicon oxynitride;
an intermediate insulating layer 202 covering the thin film transistor 6;
filter layer 8 disposed on intermediate insulating layer 202;
a passivation layer 203 covering the filter layer;
the pixel electrode 4 disposed on the passivation layer 203 is electrically connected to the drain electrode 7.
It should be noted that, the structure of the array substrate in the embodiment of the present invention is not limited to this, for example: the thin film transistor may also be a top gate thin film transistor, and of course, the structure of the array substrate may also be adaptively adjusted according to needs, which all fall within the protection scope of the present invention.
For the purpose of achieving light splitting, the implementation structure of the light splitting film 3 may be, but is not limited to, a grating structure. The light splitting principle of the light splitting film is only described by taking the grating structure as an example:
referring to fig. 1 and 3, the spectroscopic film 3 is disposed on the first substrate 1 and includes a plurality of grating periods 30, and a certain distance is provided between two adjacent grating periods 30. The period of the grating structure is the width of the grating period 30 (the width of the grating period 30 refers to the width in a direction parallel to the plane of the first substrate 100). Alternatively, the widths of all steps 31 of the grating period 30 are set to be the same.
Each grating period 30 includes a plurality of grating regions, each grating region includes at least one step 31, and each step 31 has a certain height and a certain light transmittance in a direction perpendicular to the plane of the first substrate 100. The grating periods 30 correspond to the pixel regions one-to-one, and each grating region is used for separating a sub-pixel region which transmits light of the same color and irradiates light of a specific color to the corresponding pixel region. Wherein the height of each step 31 is 0-10 μm. Optionally, the heights of the steps 31 of each grating period 30 are different from each other and are distributed according to a certain rule, so that the separated light rays of different colors are irradiated to the sub-pixel regions transmitting the light rays of the corresponding colors. Since the distribution rule of the sub-pixel regions of all the pixel regions of the display panel is the same, the plurality of steps 31 for setting all the grating periods 30 are distributed in the same manner.
Each grating period 30 generally includes 3 to 100 steps 31, and the 3 to 100 steps 31 are divided to form a plurality of grating regions, each grating region is used for separating light of a specific color from sub-pixel regions transmitting light of the same color and irradiating the sub-pixel regions to corresponding pixel regions. The heights of all steps 31 of each grating region may or may not be the same or different from each other.
Wherein, the step 31 can be made by nano-imprinting, laser thank you or e-book direct writing.
Referring to fig. 3, the principle of splitting and splitting light of the grating structure is described as follows by taking an example that each grating region includes one step 31: the light splitting is realized by utilizing the diffraction of light rays, generally, the light intensity of only 0-order or +/-1-order diffraction is higher, and the light intensity of higher-order diffraction is very small and can be ignored. Then, by adjusting the height of each step 31, the adjustment of the grating structure to the light intensity of 0-order diffraction and 1-order diffraction is realized by utilizing the interference of light. For example: using the formula of destructive interference: h (n)1–n0) M λ/2, i.e. λ 2h (n)1–n0) It can be seen that when m is 1, 3, 5 … …, 0 th order diffraction appears in the transmission valley and ± 1 st order diffraction appears in the transmission peak. Using the constructive interference formula: h (n)1–n0) M λ, i.e. λ h (n)1–n0) It can be seen that when m is 1, 2, 3 … …, 0 th order diffraction appears in the transmission peak and ± 1 st order diffraction appears in the transmission valley. Wherein h (corresponds to h indicated in the figure)1、h2、h3) Is the height of the step 31 in a direction perpendicular to the plane of the first substrate 100, n1Is the refractive index of the step 31, n0Is the refractive index of air (when the surface of the spectroscopic film on the display side is covered with a flat layer, n0The refractive index of the planarization layer). M is generally chosen to be 1, 3, 5 … … such that 0 order diffraction occurs in the transmission valley and 1 order diffraction occurs in the transmission peak, so that the interference of the most easily achieved 1 order diffraction is constructive and the 0 order diffraction interference is destructive, for the purpose of splitting, for example: red light, green light, and blue light are separated from the display light to realize color display using three primary colors of RGB.
Furthermore, the diffraction and interference effects of the grating structure can be utilized to design the steps 31 with different heights to realize the control of the diffracted light, and the monochromatic light R, G transmitted by the pixel area and the B image are ensured to be at the same height while the light splitting purpose is achieved.
Specifically, the phases of the
individual steps 31 are:
when the sub-pixel regions R, G and B correspond to the step 31When the phase difference is the same, the monochromatic lights R, G and B split by the
splitting film 3 will be imaged at the same height, that is, when the phase difference is the same
ε=(n
1-n
0) With h/λ being constant, monochromatic light R, G and B will image at the same height. And bound λ ═ 2h (n)
1–n
0) And m, when m is 1, 3 and 5 … …, 0-order diffraction appears in a transmission valley, 1-order diffraction appears in a transmission peak, epsilon is m/2, and m is an odd number, light can be split, and monochromatic light R, G or B can be imaged at the same height.
according to the imaging height principle of the grating structure, the imaging height Z of the grating structure is related to the wavelength λ of incident light and the width α of the grating period, as follows:
according to the above formula, under the condition of a certain wavelength λ of incident light, the imaging height Z is higher as the width α of the grating period is larger, and therefore, the imaging height Z of the grating structure is increased along with the increase of the width α of the grating period for a specific wavelength, and therefore, different imaging heights Z can be obtained by changing the grating period α of the grating structure within the allowable range of diffraction effect, wherein the width α of the grating period can be 0.1um-300um, the height of the
step 31 can be 0.1um-30um, and the imaging height Z can be 2-20 um.
In order to achieve a better light splitting effect of the grating structure, the phase difference between the steps 31 corresponding to different sub-pixel regions in the grating structure is preferably pi 7/6-pi 3/2, which is obtained through simulation and optimization. Wherein, when the phase difference is pi 4/3, the light splitting effect is best.
As shown in FIG. 3, taking an example that each
grating period 30 includes 3 steps, each
step 31 corresponds to one sub-pixel region R, G or B, and if the phase difference between two
adjacent steps 31 of one grating
period 30 is
π 4/3, n is n
1=n,n
0Substituting 1 into the above formula
Can be obtained asThe following formula:
let lambdar=630nm,λg=540nm,λb450nm, it can be deduced that the height difference of the three steps 31 of the grating period 30 is h1-h 3-2.05 μm, h2-h 3-3.72 μm; when h3 is 0, h1 is 2.05 μm, and h2 is 3.72 μm. Since the distribution of the sub-pixel regions is the same for all pixel regions, the distribution of the plurality of steps 31 for setting all grating periods 30 is correspondingly the same.
Each grating region of each grating period 31 is used to separate light of a specific color from sub-pixel regions transmitting light of the same color. When each grating region comprises one step 31, the height difference of two adjacent steps 31 of each grating period 30 is set to be 10nm-10 μm. In order to improve the light splitting effect, the phase difference of different steps 31 of each grating period 30 is 7 pi/6-3 pi/2.
in practical applications, when the imaging height of the grating is constant, the light transmittance of the spectroscopic film 3 can be adjusted, and the light transmittance of the spectroscopic film 3 is related to the wavelength λ of the incident light, the number of steps 31 per grating period 30 and the height of the steps 31.
The embodiment also provides a display device, which comprises the display panel, and is used for improving the light transmittance, reducing the power consumption, simultaneously improving the color gamut and reducing the thickness of a product.
The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and substitutions can be made without departing from the technical principle of the present invention, and these modifications and substitutions should also be regarded as the protection scope of the present invention.