Liquid crystal display device and electronic device

Abstract

The application discloses a liquid crystal display device and electronic equipment, the liquid crystal display device includes display liquid crystal box, quantum dot layer and the backlight module of providing blue light source;Display liquid crystal box includes color film substrate, array substrate and liquid crystal layer, display liquid crystal box is equipped with blue sub-pixel, green sub-pixel and red sub-pixel, corresponding blank area with blue sub-pixel, green color resistance corresponding with green sub-pixel and red color resistance corresponding with red sub-pixel are arranged on color film substrate, again match in quantum dot layer set up transparent area corresponding with blank area and white quantum dot area corresponding with color resistance area, white quantum dot area is equipped with white quantum dot and can excite white light, quantum dot layer is located between backlight module and liquid crystal layer, and adopts the backlight module of blue light source, so that blue light can directly penetrate transparent area and blank area, improves the light transmittance of light.

Description

Technical Field

[0001] This invention relates to the field of display technology, and in particular to a liquid crystal display device and electronic device. Background Technology

[0002] Liquid crystal displays (LCDs) have numerous advantages, including thinness, energy efficiency, and no radiation, leading to their widespread use. Examples include LCD televisions, mobile phones, personal digital assistants (PDAs), digital cameras, computer screens, and laptop screens, where they dominate the flat panel display field.

[0003] Traditional liquid crystal display (LCD) panels consist of a color filter substrate (CF), a thin-film transistor array substrate (TFT array substrate), and a liquid crystal layer filling the space between the two substrates. Traditional LCD devices achieve color display by using color filters coated with red, green, and blue color resists to filter the monochromatic light (usually white light) provided by the backlight module. Typically, three sub-pixels with the same aperture ratio (red, green, and blue) constitute one pixel. Due to the filtering properties of the color resists, different intensities of red, green, and blue light can be obtained. A color image is then produced by mixing these three primary colors.

[0004] However, since the backlight module directly provides white light, it also contains other non-visible light, resulting in low purity white light. Therefore, to improve the color gamut of the LCD panel, existing technologies typically require thicker color resists on the color filter to obtain higher purity red, green, and blue light. However, this leads to lower light transmittance of the color filter and higher power consumption of the backlight module. Existing technologies generally increase light transmittance by reducing opaque areas to increase the panel aperture ratio and maximize transmittance. However, limitations in manufacturing precision, such as metal linewidth and BM (black matrix) linewidth, are limited by exposure and development capabilities, resulting in limited improvement in transmittance. Furthermore, solely relying on reducing metal linewidth can affect the resistance, impacting panel power consumption and even display panel image quality. Summary of the Invention

[0005] In order to overcome the shortcomings and deficiencies of the prior art, the present invention aims to provide a liquid crystal display device and electronic device to solve the problem of low light transmittance of liquid crystal display panels in the prior art.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] The present invention provides a liquid crystal display device, including a display liquid crystal cell, a quantum dot layer and a backlight module, wherein the display liquid crystal cell is used to control the grayscale brightness of the displayed image and the backlight module is used to provide a blue light source;

[0008] The display liquid crystal cell includes a color filter substrate, an array substrate disposed opposite to the color filter substrate, and a liquid crystal layer located between the color filter substrate and the array substrate. The color filter substrate has a blank area and a color resist area. The color filter substrate has a red color resist and a green color resist in the color resist area. The display liquid crystal cell has a plurality of pixel units arranged in an array. The plurality of pixel units have a blue sub-pixel, a green sub-pixel, and a red sub-pixel. The blank area corresponds to the blue sub-pixel, the green color resist corresponds to the green sub-pixel, and the red color resist corresponds to the red sub-pixel.

[0009] The quantum dot layer is located between the backlight module and the liquid crystal layer. The quantum dot layer includes a transparent area and a white quantum dot area. The white quantum dot area is provided with white quantum dots and can emit white light. The transparent area corresponds to the blank area, and the white quantum dot area corresponds to the color resist area.

[0010] Furthermore, the quantum dot layer is disposed on the side of the array substrate facing the liquid crystal layer; or, the quantum dot layer is disposed between the backlight module and the array substrate.

[0011] Furthermore, the array substrate is provided with a long-pass filter corresponding to the white quantum dot region. The long-pass filter is located on the light-emitting side of the quantum dot layer and can transmit red and green light and reflect blue light.

[0012] Furthermore, the liquid crystal display device includes a light-filtering liquid crystal cell, which includes a first substrate, a second substrate disposed opposite to the first substrate, and a cholesteric liquid crystal layer located between the first substrate and the second substrate. The cholesteric liquid crystal layer is located on the light-emitting side of the quantum dot layer, and the cholesteric liquid crystal layer reflects blue light in the reflective state.

[0013] In the display state, the filter liquid crystal cell has a transmissive area and a reflective area. The transmissive area corresponds to the transparent area, and the reflective area corresponds to the white quantum dot area. The transmissive area is used to transmit blue light when displaying the image, and the reflective area is used to reflect blue light and transmit red and green light when displaying the image.

[0014] Furthermore, the first substrate is provided with a common electrode, and the second substrate is provided with a first control electrode and a second control electrode that cooperate with the common electrode. The first control electrode corresponds to the transmission region, and the second control electrode corresponds to the reflection region.

[0015] Furthermore, the quantum dot layer is disposed on the side of the second substrate facing the cholesteric liquid crystal layer; or, the quantum dot layer is disposed between the backlight module and the second substrate.

[0016] Furthermore, a metal wire grid polarizer is provided on the side of the array substrate facing the liquid crystal layer. The metal wire grid polarizer is located on the light-emitting side of the quantum dot layer. A polarizer is provided on the color filter substrate. The transmission axis of the polarizer is perpendicular to the transmission axis of the metal wire grid polarizer.

[0017] Furthermore, the array substrate has a pixel electrode and a common electrode that cooperates with the pixel electrode on the side facing the liquid crystal layer, and the metal wire grid polarizer is reused as the pixel electrode or the common electrode;

[0018] And / or, the surface of the metal wire grid polarizer facing the liquid crystal layer is provided with an anti-reflection layer, the metal wire grid polarizer includes multiple parallel and spaced metal lines, and the anti-reflection layer includes multiple parallel and spaced light-absorbing lines, the light-absorbing lines corresponding one-to-one with the metal lines.

[0019] Furthermore, a quarter-wave plate is provided on the color filter substrate, and the quarter-wave plate is located on the side of the polarizer facing the liquid crystal layer, with the fast and slow axes of the quarter-wave plate at 45° to the light transmission axis of the polarizer.

[0020] This application also provides an electronic device, including the liquid crystal display device described above.

[0021] The beneficial effects of this invention are as follows: by setting a blank area corresponding to the blue sub-pixel, a green color resist corresponding to the green sub-pixel, and a red color resist corresponding to the red sub-pixel on the color filter substrate, and then setting a transparent area corresponding to the blank area and a white quantum dot area corresponding to the color resist area on the quantum dot layer, and using a backlight module with a blue light source, blue light can directly pass through the transparent area and the blank area, thereby improving the light transmittance. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the liquid crystal display device in its initial state according to Embodiment 1 of the present invention;

[0023] Figure 2 This is a schematic diagram of the planar structure of the array substrate in Embodiment 1 of the present invention;

[0024] Figure 3 This is a schematic diagram of the planar structure of the color filter substrate in Embodiment 1 of the present invention;

[0025] Figure 4This is a schematic diagram of the planar structure of the quantum dot layer in Embodiment 1 of the present invention;

[0026] Figure 5 This is a schematic diagram of the liquid crystal display device in display state according to Embodiment 1 of the present invention;

[0027] Figure 6 This is a schematic diagram of the liquid crystal display device in its initial state according to Embodiment 2 of the present invention;

[0028] Figure 7 This is a schematic diagram of the liquid crystal display device in display mode according to Embodiment 2 of the present invention;

[0029] Figure 8 This is a schematic diagram of the liquid crystal display device in its initial state according to Embodiment 3 of the present invention;

[0030] Figure 9 This is a schematic diagram of the liquid crystal display device in display mode according to Embodiment 3 of the present invention;

[0031] Figure 10 This is a schematic diagram of the liquid crystal display device in its initial state according to Embodiment 4 of the present invention;

[0032] Figure 11 This is a transmittance curve of the long-pass filter for different light rays in Embodiment 4 of the present invention;

[0033] Figure 12 This is a reflection curve of the long-pass filter for light rays at different incident angles in Embodiment 4 of the present invention;

[0034] Figure 13 This is a schematic diagram of the liquid crystal display device in display mode according to Embodiment 4 of the present invention;

[0035] Figure 14 This is a schematic diagram of the optical path of the liquid crystal display device in display mode according to Embodiment 4 of the present invention;

[0036] Figure 15 This is a schematic diagram of the liquid crystal display device in its initial state according to Embodiment 5 of the present invention;

[0037] Figure 16 This is a schematic diagram illustrating the principle of the three state transformations of cholesteric liquid crystal in Embodiment 5 of the present invention;

[0038] Figure 17 This is a schematic diagram of the driving signals for the three state transitions of cholesteric liquid crystal in Embodiment 5 of the present invention;

[0039] Figure 18 This is a schematic diagram of the structure and optical path of the liquid crystal display device in display mode according to Embodiment 5 of the present invention;

[0040] Figure 19This is a schematic diagram of the planar structure of the filter liquid crystal cell in the display state in Embodiment 5 of the present invention. Detailed Implementation

[0041] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the specific implementation methods, structures, features, and effects of the liquid crystal display device and electronic device according to the present invention are described in detail below with reference to the accompanying drawings and preferred embodiments:

[0042] [Example 1]

[0043] Figure 1 This is a schematic diagram of the liquid crystal display device in its initial state according to Embodiment 1 of the present invention. Figure 2 This is a schematic diagram of the planar structure of the array substrate in Embodiment 1 of the present invention. Figure 3 This is a schematic diagram of the planar structure of the color filter substrate in Embodiment 1 of the present invention. Figure 4 This is a schematic diagram of the planar structure of the quantum dot layer in Embodiment 1 of the present invention. Figure 5 This is a schematic diagram of the liquid crystal display device in display mode according to Embodiment 1 of the present invention.

[0044] like Figures 1 to 5 As shown in Embodiment 1 of the present invention, a liquid crystal display device includes a display liquid crystal cell 10, a quantum dot layer 20, and a backlight module 30. Both the display liquid crystal cell 10 and the quantum dot layer 20 are disposed on the light-emitting side of the backlight module 30, wherein the light-emitting side faces the external environment. The display liquid crystal cell 10 is used to control the grayscale brightness of the displayed image, and the backlight module 30 is used to provide a blue light source. The backlight module 30 can use a blue LED as the light source to emit blue light.

[0045] like Figure 3 As shown, the display liquid crystal cell 10 is provided with a plurality of pixel units P arranged in an array. Each pixel unit P has a blue sub-pixel P1, a green sub-pixel P2, and a red sub-pixel P3. A column of blue sub-pixels P1, a column of green sub-pixels P2, and a column of red sub-pixels P3 are arranged periodically in the row direction.

[0046] The display liquid crystal cell 10 includes a color filter substrate 11, an array substrate 12 disposed opposite to the color filter substrate 11, and a liquid crystal layer 13 located between the color filter substrate 11 and the array substrate 12. The array substrate 12, the liquid crystal layer 13, and the color filter substrate 11 are arranged sequentially on the side facing the external environment. The liquid crystal layer 13 uses positive liquid crystal molecules, that is, liquid crystal molecules with positive dielectric anisotropy. Figure 1As shown, in the initial state, the positive liquid crystal molecules in the liquid crystal layer 13 are aligned parallel to the color filter substrate 11 and the array substrate 12. The alignment directions of the positive liquid crystal molecules near the color filter substrate 11 and the positive liquid crystal molecules near the array substrate 12 are parallel or antiparallel to each other. Of course, in other embodiments, the positive liquid crystal molecules in the liquid crystal layer 13 are aligned parallel to the color filter substrate 11 and the array substrate 12, and the alignment directions of the positive liquid crystal molecules near the color filter substrate 11 and the positive liquid crystal molecules near the array substrate 12 can also be perpendicular to each other, i.e., the positive liquid crystal molecules in the liquid crystal layer 13 are twisted by 90° to form a TN display mode. Alternatively, the liquid crystal layer 13 can also use negative liquid crystal molecules, which can be aligned perpendicular to the color filter substrate 11 and the array substrate 12, similar to the alignment method of the VA display mode.

[0047] The color filter substrate 11 has a blank area 11a and a color resist area 11b. A color resist layer 112 is provided in the color resist area 11b, comprising a red color resist 112r and a green color resist 112g. The blank area 11a is covered by a planarization layer (OC) material. The blank area 11a corresponds to the blue sub-pixel P1, the green color resist 112g corresponds to the green sub-pixel P2, and the red color resist 112r corresponds to the red sub-pixel P3. The color filter substrate 11 also has a black matrix (BM) 111, located between the blank area 11a, the red color resist 112r, and the green color resist 112g, such that adjacent pixel units P are separated from each other by the black matrix 111.

[0048] The quantum dot layer 20 is located between the backlight module 30 and the liquid crystal layer 13. The quantum dot layer 20 includes a transparent area 201 and a white quantum dot area 202. The white quantum dot area 202 is provided with white quantum dots and can emit white light. The transparent area 201 corresponds to the blank area 11a, and the white quantum dot area 202 corresponds to the color resist area 11b.

[0049] Quantum dots (QDs) are typically nanoparticles composed of group II-V1 or III-V elements, with sizes smaller than or close to the exciton Bohr radius (generally no more than 10 nm in diameter). Examples include spherical or near-spherical particles with diameters of 2-20 nm composed of zinc, cadmium, selenium, and sulfur atoms, exhibiting significant quantum effects. They are generally considered quasi-zero-dimensional materials, semiconductor nanostructures that bind conduction band electrons, valence band holes, and excitons in three spatial directions.

[0050] When the particle size of nanomaterials decreases to a certain value (generally below 10 nm), the electronic energy levels near the Fermi level of the metal change from quasi-continuous to discrete. The energy gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital energy levels of the nano-semiconductor particles widens, thereby causing a blue shift in the absorption and fluorescence spectrum peaks. This phenomenon is called the quantum size effect.

[0051] The quantum size effect dramatically alters the photoelectric properties of semiconductor quantum dots. When the size of semiconductor quantum dot particles is smaller than the Bohr radius of excitons, the resulting quantum size effect changes the energy level structure of the semiconductor material, transforming it from a continuous band structure into a discrete energy level structure with molecular characteristics. This phenomenon can be used to prepare semiconductor quantum dots of different sizes in the same reaction, producing light emission at different frequencies, thus allowing for convenient control of various emission colors.

[0052] When a solid absorbs a photon (absorption), the energy of the absorbed photon will be greater than that of the emitted photon (emission). Therefore, the emission spectrum will be shifted (redshift) towards a lower energy direction compared to the absorption spectrum. The difference in energy between the two photons is called the Stokes shift.

[0053] Because quantum dots have a narrow emission spectrum and high luminous efficiency, and possess quantum size effect and Stokes spectral shift effect, the quantum dots corresponding to each color sub-pixel can absorb light with energy greater than that of the color unit emitted by the backlight, and efficiently convert the absorbed light into monochromatic light of that sub-pixel unit color and emit it, making the color corresponding to that color sub-pixel purer, with higher saturation, and improving the transmittance of the backlight.

[0054] In this embodiment, the quantum dot layer 20 is disposed on the side of the array substrate 12 facing the liquid crystal layer 13. The quantum dot layer 20 can be made of planarization layer (OC) material and white quantum dots. The transparent area 201 is covered by the planarization layer (OC), and the white quantum dot area 202 is formed by mixing the planarization layer (OC) material and white quantum dots. This allows the quantum dot layer 20 to also function as a planarization layer, thereby planarizing the electrodes of the array substrate 12 and reducing the cell thickness. Of course, in other embodiments, the quantum dot layer 20 can also be disposed between the backlight module 30 and the array substrate 12, for example, on the side of the array substrate 12 facing the backlight module 30.

[0055] like Figure 1 and 2As shown, the array substrate 12 has multiple pixel units P formed by multiple scan lines 1 and multiple data lines 2 that are mutually insulated and intersecting on the side facing the liquid crystal layer 13. The black matrix 111 corresponds vertically to the scan lines 1 and data lines 2. Each pixel unit P is provided with a pixel electrode 122 and a thin-film transistor 3. The pixel electrode 122 is electrically connected to the data line 2 of the adjacent thin-film transistor 3 through the thin-film transistor 3. The thin-film transistor 3 includes a gate, an active layer, a drain, and a source. The gate is located on the same layer as the scan line 1 and is electrically connected. The gate is isolated from the active layer by an insulating layer. The source is electrically connected to the data line 2, and the drain is electrically connected to the pixel electrode 122 through a contact hole.

[0056] In this embodiment, a common electrode 121 is further provided on the side of the array substrate 12 facing the liquid crystal layer 13. The common electrode 121 and the pixel electrode 122 are located on different layers and are insulated and isolated by an insulating layer. The common electrode 121 may be located above or below the pixel electrode 122. Figure 1 The diagram shows the common electrode 121 located below the pixel electrode 122. Preferably, the common electrode 121 is a planar electrode with its entire surface, and the pixel electrode 122 is a slit electrode with multiple electrode strips in each pixel unit P to form a fringe field switching (FFS) mode. Of course, in other embodiments, the pixel electrode 122 and the common electrode 121 are located on the same layer, but they are insulated from each other. Both the pixel electrode 122 and the common electrode 121 may include multiple electrode strips, and the electrode strips of the pixel electrode 122 and the common electrode 121 are arranged alternately to form an in-plane switching (IPS) mode. Alternatively, the array substrate 12 has the pixel electrode 122 on the side facing the liquid crystal layer 13, and the color filter substrate 11 has the common electrode 121 on the side facing the liquid crystal layer 13 to form a TN mode or a VA mode. For further descriptions of the TN mode and VA mode, please refer to the prior art, which will not be repeated here.

[0057] In this embodiment, a full-surface metal wire grid polarizer 123 is provided on the side of the array substrate 12 facing the liquid crystal layer 13. The metal wire grid polarizer 123 is located on the light-emitting side of the quantum dot layer 20. A polarizer 113 is provided on the color filter substrate 11, and the transmission axis of the polarizer 113 is perpendicular to the transmission axis of the metal wire grid polarizer 123. The metal wire grid polarizer 123 has mutually perpendicular transmission and reflection axes. By providing the metal wire grid polarizer 123 on the side of the array substrate 12 facing the liquid crystal layer 13, it can not only perform polarization but also improve the utilization rate of light through reflection. The metal wire grid polarizer 123 is preferably made of Al / Mo, but other metal materials are also acceptable. The wire grid pitch is less than or equal to 50-500 nm, the thickness is 40-400 nm, and it is manufactured using a nanoimprint lithography process. The metal wire grid polarizer 123 can convert the blue light emitted by the backlight module 30 and the white light excited by the quantum dots into linearly polarized light.

[0058] In this embodiment, a quarter-wave plate 114 is also provided on the color filter substrate 11. The quarter-wave plate 114 is disposed on the side of the polarizer 113 facing the liquid crystal layer 13, and the fast and slow axes of the quarter-wave plate 114 are at 45° to the light transmission axis of the polarizer 113. By using the quarter-wave plate 114 in conjunction with the polarizer 113, the quarter-wave plate 114 and the polarizer 113 together form a circular polarizer, thereby preventing the display liquid crystal cell 10 from reflecting ambient light and improving the light utilization rate.

[0059] The color filter substrate 11 and the array substrate 12 can be made of materials such as glass, acrylic, and polycarbonate. The common electrode 121 and the pixel electrode 122 can be made of transparent conductive materials such as indium tin oxide (ITO) or indium zinc oxide (IZO).

[0060] This application also provides an electronic device, including the liquid crystal display device described above.

[0061] [Example 2]

[0062] Figure 6 This is a schematic diagram of the liquid crystal display device in its initial state according to Embodiment 2 of the present invention. Figure 7 This is a schematic diagram of the liquid crystal display device in display mode according to Embodiment 2 of the present invention. Figure 6 and Figure 7 As shown, the liquid crystal display device and electronic device provided in Embodiment 2 of the present invention are similar to those in Embodiment 1. Figures 1 to 5 The liquid crystal display device and electronic equipment in this embodiment are basically the same, except that in this embodiment:

[0063] The metal wire grid polarizer 123 is reused as a common electrode 121. That is, the metal wire grid polarizer 123 not only has a light transmission axis and a light reflection axis, but also acts as a common electrode 121 to apply a common signal. Therefore, it is not necessary to set a separate common electrode 121, thereby reducing the cell thickness and lowering the manufacturing process difficulty and production cost. Of course, in other embodiments, the metal wire grid polarizer 123 can also be reused as a pixel electrode 122. Since the pixel electrode 122 corresponds one-to-one with the pixel unit P, the metal wire grid polarizer 123 also needs to be divided into a structure corresponding one-to-one with the pixel unit P.

[0064] Those skilled in the art should understand that the remaining structures and working principles of this embodiment are the same as those of Embodiment 1, and will not be repeated here.

[0065] [Example 3]

[0066] Figure 8 This is a schematic diagram of the liquid crystal display device in its initial state according to Embodiment 3 of the present invention. Figure 9 This is a schematic diagram of the liquid crystal display device in display mode according to Embodiment 3 of the present invention. Figure 8 and Figure 9 As shown, the liquid crystal display device and electronic device provided in Embodiment 3 of the present invention are similar to those in Embodiment 1. Figures 1 to 5 Example 2 Figure 6 and Figure 7 The liquid crystal display device and electronic equipment in this embodiment are basically the same, except that in this embodiment:

[0067] An anti-reflection layer 124 is provided on the surface of the metal wire grid polarizer 123 facing the liquid crystal layer 13. The metal wire grid polarizer 123 includes multiple parallel and spaced metal traces, and the anti-reflection layer 124 includes multiple parallel and spaced light-absorbing traces, with each light-absorbing trace corresponding to one of the metal traces. Preferably, the anti-reflection layer 124 is made of a metal oxide (e.g., molybdenum oxide, formed by first creating a layer of molybdenum metal and then oxidizing it). However, the anti-reflection layer 124 can also be made of other light-absorbing materials.

[0068] In this embodiment, the anti-reflection layer 124 is disposed on the surface of the metal wire grid polarizer 123 away from the quantum dot layer 20 and is in direct contact with the metal wire grid polarizer 123. That is, the anti-reflection layer 124 is directly fabricated on the surface of the metal wire grid polarizer 123. No other dielectric layer needs to be disposed between the metal wire grid polarizer 123 and the anti-reflection layer 124. The anti-reflection layer 124 can also provide a certain degree of protection for the metal wire grid polarizer 123, preventing it from being oxidized. Of course, in other embodiments, the anti-reflection layer 124 may not be directly disposed on the surface of the metal wire grid polarizer 123. Other layers (such as a common electrode 121, a pixel electrode 122, or an insulating layer) can be disposed between the anti-reflection layer 124 and the metal wire grid polarizer 123. It is only necessary that the light-absorbing traces of the anti-reflection layer 124 correspond one-to-one with the metal traces of the metal wire grid polarizer 123.

[0069] Those skilled in the art should understand that the remaining structures and working principles of this embodiment are the same as those of Embodiment 1 and Embodiment 2, and will not be repeated here.

[0070] [Example 4]

[0071] Figure 10 This is a schematic diagram of the liquid crystal display device in its initial state according to Embodiment 4 of the present invention. Figure 10 As shown, the liquid crystal display device and electronic device provided in Embodiment 4 of the present invention are similar to those in Embodiment 1. Figures 1 to 5 Example 2 Figure 6 and Figure 7 Example 3 Figure 8 and Figure 9 The liquid crystal display device and electronic equipment in this embodiment are basically the same, except that in this embodiment:

[0072] A long-pass filter 125 corresponding to the white quantum dot region 202 is provided on the array substrate 12, that is, the long-pass filter 125 corresponds to the color resist region 11b on the color filter substrate 11. The long-pass filter 125 is located on the light-emitting side of the quantum dot layer 20, and the long-pass filter 125 can transmit red and green light and reflect blue light. Since the white quantum dots in the white quantum dot region 202 emit white light, the long-pass filter 125 can transmit the red and green light in the white light and reflect the blue light and other light in the white light, so that the blue light and other light can be reused by the white quantum dots to improve the color purity of the green sub-pixel P2 and the red sub-pixel P3 and the utilization rate of the backlight.

[0073] Both the long-pass filter 125 (Short-pass filter, SPF) and the short-pass filter (Long-pass filter, LPF) are distributed Bragg reflectors (DBRs). The short-pass filter transmits blue light with wavelengths below 490 nm and reflects red and green light with wavelengths between 500 and 680 nm, while the long-pass filter 125 transmits red and green light with wavelengths between 500 and 680 nm and reflects blue light with wavelengths below 490 nm. Distributed Bragg reflectors (DBRs) are reflectors used in waveguides. The long-pass filter 125 and the short-pass filter use SiO2 (silicon dioxide) and TiO2 (titanium dioxide) as alternating materials, achieving two different bandpasses in the DBR by adjusting the film thickness and logarithm. When light passes through different media, it is reflected at the interface. The reflectivity is related to the refractive indices of the media. Therefore, if we periodically stack thin films with different refractive indices, when light passes through these films, the reflected light from each layer undergoes constructive interference due to the change in phase angle, and then combines with each other to produce strongly reflected light. If the number of layers becomes very large, and the difference in refractive indices n1, n2, n3, etc., becomes very small, the light travels as if it were in a single medium, and the reflection coefficient becomes very small. The interference effect caused by the multiple interferences of light is very significant, making it very sensitive to wavelength selection. When using a grating-like structure, this periodic structure is called a distributed Bragg reflector.

[0074] Figure 11 This is a transmittance curve of the long-pass filter for different light rays in Embodiment 4 of the present invention, as shown in the figure. Figure 11 As shown in the figure, curves R, G, and B represent the wavelengths of red, green, and blue light, respectively, and curve L represents the transmittance of the long-pass filter 125 for different wavelengths of light. Figure 11 It can be seen that the long-pass filter 125 has a good transmission effect on red and green light with wavelengths of 500-680nm, and the transmittance can reach more than 95%.

[0075] Figure 12 This is a reflection curve of the long-pass filter for light rays at different incident angles in Embodiment 4 of the present invention, as shown in the figure. Figure 12 As shown, curves L1, L2, L3, and L4 represent the reflectivity of the long-pass filter 125 for white light with incident angles of 0°, 20°, 40°, and 60°, respectively. Figure 12It can be seen that when the incident light angle is less than 40°, the long-pass filter 125 has a reflectivity of 94% for blue light in the 400-500nm range, which reduces the transmittance of blue light in the green sub-pixel P2 and the red sub-pixel P3 and improves the utilization rate of blue light.

[0076] Figure 13 This is a schematic diagram of the liquid crystal display device in display mode according to Embodiment 4 of the present invention. Figure 14 This is a schematic diagram of the optical path of the liquid crystal display device in display mode according to Embodiment 4 of the present invention. Figure 13 and Figure 14 As shown, in the display state, the backlight module 30 provides a blue light source. The blue light corresponding to the blue sub-pixel P1 region can directly pass through the transparent area 201 in the quantum dot layer 20 and the blank area 11a on the color filter substrate 11 and be emitted. The blue light corresponding to the green sub-pixel P2 and red sub-pixel P3 regions is excited to produce white light through the white quantum dot area 202 of the quantum dot layer 20. The blue light in the white light is reflected back by the long-pass filter 125 for reuse. The red and green light in the white light can pass through the long-pass filter 125 and be filtered by the color resist area 11b on the color filter substrate 11 before being emitted, thereby improving the color purity of the green sub-pixel P2 and the red sub-pixel P3 and the utilization rate of the backlight.

[0077] Those skilled in the art should understand that the remaining structures and working principles of this embodiment are the same as those of Embodiment 1, Embodiment 2, and Embodiment 3, and will not be repeated here.

[0078] [Example 5]

[0079] Figure 15 This is a schematic diagram of the liquid crystal display device in its initial state according to Embodiment 5 of the present invention. Figure 15 As shown, the liquid crystal display device and electronic device provided in Embodiment 5 of the present invention are similar to those in Embodiment 1. Figures 1 to 5 Example 2 Figure 6 and Figure 7 Example 3 Figure 8 and Figure 9 Example 4 Figure 10 and Figure 14 The liquid crystal display device and electronic equipment in this embodiment are basically the same, except that in this embodiment:

[0080] The liquid crystal display device includes a light-filtering liquid crystal cell 40. The light-filtering liquid crystal cell 40 includes a first substrate 41, a second substrate 42 disposed opposite to the first substrate 41, and a cholesteric liquid crystal layer 43 located between the first substrate 41 and the second substrate 42. The second substrate 42, the cholesteric liquid crystal layer 43, and the first substrate 41 are sequentially arranged on the side facing the external environment. The cholesteric liquid crystal layer 43 is located on the light-emitting side of the quantum dot layer 20, and in its reflective state, the cholesteric liquid crystal layer 43 reflects blue light. In the display state, the light-filtering liquid crystal cell 40 has a transmissive region 401 and a reflective region 402. The transmissive region 401 corresponds to the transparent region 201, and the reflective region 402 corresponds to the white quantum dot region 202. The transmissive region 401 transmits blue light when displaying an image, and the reflective region 402 reflects blue light and transmits red and green light when displaying an image. Since the white quantum dots in the white quantum dot region 202 emit white light, the reflective region 402 of the filter liquid crystal cell 40 can transmit red and green light in the white light and reflect blue light in the white light, so that blue light and other light can be reused by the white quantum dots to improve the color purity of the green sub-pixel P2 and the red sub-pixel P3 as well as the utilization rate of backlight.

[0081] Furthermore, a common electrode 411 is provided on the first substrate 41, and a first control electrode 421 and a second control electrode 422 are provided on the second substrate 42 to cooperate with the common electrode 411. The first control electrode 421 corresponds to the transmission region 401, and the second control electrode 422 corresponds to the reflection region 402.

[0082] The cholesteric liquid crystal in the cholesteric liquid crystal layer 43 possesses three stable textures: P-state (Planar, reflective state), FC-state (Focal Conic, hazy state), and H-state (transparent state). In the P-state, the cholesteric liquid crystal's reflection spectrum is in the visible spectrum, reflecting bright colored light; the specific reflected color can be set according to the pitch of the cholesteric liquid crystal. In the FC-state, the cholesteric liquid crystal no longer reflects the aforementioned colored light, and light can be scattered and transmitted through it. In the H-state, the cholesteric liquid crystal no longer reflects the aforementioned colored light, and light can pass directly through it without any scattering effect. The P-state and FC-state do not require voltage to maintain; that is, the P-state and FC-state are stable states. Under a certain electric field, these three states can be interconverted, or the cholesteric liquid crystal layer 43 can be initially aligned into a focal conic (transmittance) state and a reflective state through alignment. Different arrangement directions of the cholesteric liquid crystal result in different reflected visible light spectra, with the remaining spectrum transmitted. The reflection spectral band (Δλ) of the cholesteric liquid crystal is proportional to its pitch (Po) and birefringence (Δn = ne - no), as expressed by the formula: Δλ = PoΔn. Therefore, cholesteric liquid crystals with different pitches can reflect different colors of light in the reflective state. In this embodiment, the pitch of the cholesteric liquid crystal in the cholesteric liquid crystal layer 43 is 190–340 nm, thus enabling it to reflect blue light in the reflective state.

[0083] Figure 16 This is a schematic diagram illustrating the principle of the three state transformations of cholesteric liquid crystal in Embodiment 5 of the present invention. Figure 17 This is a schematic diagram of the driving signals for the three state transitions of the cholesteric liquid crystal in Embodiment 5 of the present invention. Figure 16 and Figure 17As shown, a common voltage signal Vcom is applied to the common electrode 411, and a first electrical signal V1 is continuously applied to the control electrodes (first control electrode 421, second control electrode 422). There is a voltage difference (e.g., 16V) between the common voltage signal Vcom and the first electrical signal V1. A strong vertical electric field is formed between the common electrode 411 and the control electrode. The cholesteric liquid crystal in the cholesteric liquid crystal layer 13 rotates and stagnates in the H state (transparent state). A common voltage signal Vcom is applied to the common electrode 411, and a second electrical signal V2 is applied to the control electrode. There is a voltage difference (e.g., 16V) between the second electrical signal V2 and the common voltage signal Vcom. The second electrical signal V2 gradually becomes the same as the common voltage signal Vcom within a first preset time. That is, the second electrical signal V2 first has a large voltage difference with the common voltage signal Vcom, and then slowly decreases and becomes the same as the common voltage signal Vcom. Therefore, a strong vertical electric field is initially formed between the common electrode 411 and the control electrode. This vertical electric field then slowly disappears, causing the cholesteric liquid crystal in the cholesteric liquid crystal layer 13 to rotate and remain stationary in the FC state, which is a scattering state and has a light-scattering effect. A common voltage signal Vcom is applied to the common electrode 411, and a third electrical signal V3 is applied to the control electrode. There is a voltage difference (e.g., 16V) between the third electrical signal V3 and the common voltage signal Vcom. The third electrical signal V3 directly becomes the same as the common voltage signal Vcom at a second preset time. The second preset time is shorter than the first preset time; that is, the third electrical signal V3 initially has a large voltage difference with the common voltage signal Vcom, and then rapidly decreases to become the same as the common voltage signal Vcom. Therefore, a strong vertical electric field is initially formed between the common electrode 411 and the control electrode. This vertical electric field then rapidly disappears, causing the cholesteric liquid crystal in the cholesteric liquid crystal layer 13 to rotate and remain stationary in the P state, which is a reflecting state.

[0084] In this embodiment, the quantum dot layer 20 is disposed on the side of the second substrate 42 facing the cholesteric liquid crystal layer 43. The quantum dot layer 20 can be made of a planarization layer (OC) material and white quantum dots. The transparent area 201 is covered by the planarization layer (OC), and the white quantum dot area 202 is formed by mixing the planarization layer (OC) material and white quantum dots. This allows the quantum dot layer 20 to also function as a planarization layer, thereby planarizing the electrodes of the array substrate 12 and reducing the cell thickness. In other embodiments, the quantum dot layer 20 is disposed between the backlight module 30 and the second substrate 42; for example, the quantum dot layer 20 is disposed on the side of the second substrate 42 facing the backlight module 30.

[0085] Figure 18 This is a schematic diagram of the structure and optical path of the liquid crystal display device in the display state according to Embodiment 5 of the present invention. Figure 19 This is a schematic diagram of the planar structure of the filter liquid crystal cell in display mode according to Embodiment 5 of the present invention. Figure 18 and Figure 19 As shown, in the display state, the cholesteric liquid crystal layer 43 corresponding to the transmission region 401 is controlled to be in a transmission state (e.g., focal conic or transparent state), and the cholesteric liquid crystal layer 43 corresponding to the reflection region 402 is controlled to be in a reflection state. The backlight module 30 provides a blue light source. The blue light corresponding to the blue sub-pixel P1 region can directly pass through the transparent area 201 in the quantum dot layer 20, the transmissive area 401 in the filter liquid crystal cell 40, and the blank area 11a on the color filter substrate 11 and be emitted. The blue light corresponding to the green sub-pixel P2 and red sub-pixel P3 regions is excited to produce white light through the white quantum dot area 202 of the quantum dot layer 20. The blue light in the white light is reflected back by the cholesteric liquid crystal layer 43 of the reflective area 402 in the filter liquid crystal cell 40 for reuse. The red and green light in the white light can pass through the cholesteric liquid crystal layer 43 of the reflective area 402 and be filtered by the color resist area 11b on the color filter substrate 11 before being emitted. This can improve the color purity of the green sub-pixel P2 and the red sub-pixel P3 and the utilization rate of the backlight.

[0086] Those skilled in the art should understand that the remaining structures and working principles of this embodiment are the same as those of Embodiment 1, Embodiment 2, Embodiment 3, and Embodiment 4, and will not be repeated here.

[0087] In this document, the directional terms such as up, down, left, right, front, and back are defined according to the position of the structures in the accompanying drawings and the relative positions of the structures, and are only used for clarity and convenience in expressing the technical solution. It should be understood that the use of these directional terms should not limit the scope of protection claimed in this application. It should also be understood that the terms "first" and "second," etc., used herein are only used for distinction in name and are not used to limit the number or order.

[0088] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content without departing from the scope of the technical solution of the present invention, which are equivalent embodiments with equivalent changes. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the technical solution of the present invention shall still fall within the protection scope of the technical solution of the present invention.

Claims

1. A liquid crystal display device, characterized in that, It includes a display liquid crystal cell (10), a quantum dot layer (20), and a backlight module (30). The display liquid crystal cell (10) is used to control the grayscale brightness of the display screen, and the backlight module (30) is used to provide a blue light source. The display liquid crystal cell (10) includes a color filter substrate (11), an array substrate (12) disposed opposite to the color filter substrate (11), and a liquid crystal layer (13) located between the color filter substrate (11) and the array substrate (12). The color filter substrate (11) has a blank area (11a) and a color resist area (11b). The color filter substrate (11) has a red color resist (112r) and a green color resist (112g) in the color resist area (11b). The display liquid crystal cell (10) has a plurality of pixel units (P) arranged in an array. The plurality of pixel units (P) have a blue sub-pixel (P1), a green sub-pixel (P2), and a red sub-pixel (P3). The blank area (11a) corresponds to the blue sub-pixel (P1), the green color resist (112g) corresponds to the green sub-pixel (P2), and the red color resist (112r) corresponds to the red sub-pixel (P3). The quantum dot layer (20) is located between the backlight module (30) and the liquid crystal layer (13). The quantum dot layer (20) includes a transparent area (201) and a white quantum dot area (202). The white quantum dot area (202) is provided with white quantum dots and can emit white light. The transparent area (201) corresponds to the blank area (11a), and the white quantum dot area (202) corresponds to the color resist area (11b). The quantum dot layer (20) is made of planarization material and white quantum dots, the transparent area (201) is covered by planarization material, and the white quantum dot area (202) is formed by mixing planarization material and white quantum dots, so that the quantum dot layer (20) can also be used as a planarization layer.

2. The liquid crystal display device according to claim 1, characterized in that, The quantum dot layer (20) is disposed on the side of the array substrate (12) facing the liquid crystal layer (13); or, the quantum dot layer (20) is disposed between the backlight module (30) and the array substrate (12).

3. The liquid crystal display device according to claim 1, characterized in that, The array substrate (12) is provided with a long-pass filter (125) corresponding to the white quantum dot region (202). The long-pass filter (125) is located on the light-emitting side of the quantum dot layer (20). The long-pass filter (125) can transmit red and green light and reflect blue light.

4. The liquid crystal display device according to claim 1, characterized in that, The liquid crystal display device includes a light-filtering liquid crystal cell (40), which includes a first substrate (41), a second substrate (42) disposed opposite to the first substrate (41), and a cholesteric liquid crystal layer (43) located between the first substrate (41) and the second substrate (42). The cholesteric liquid crystal layer (43) is located on the light-emitting side of the quantum dot layer (20), and the cholesteric liquid crystal layer (43) reflects blue light in the reflective state. In the display state, the filter liquid crystal cell (40) has a transmissive area (401) and a reflective area (402). The transmissive area (401) corresponds to the transparent area (201), and the reflective area (402) corresponds to the white quantum dot area (202). The transmissive area (401) is used to transmit blue light when displaying the image, and the reflective area (402) is used to reflect blue light and transmit red and green light when displaying the image.

5. The liquid crystal display device according to claim 4, characterized in that, The first substrate (41) is provided with a common electrode (411), and the second substrate (42) is provided with a first control electrode (421) and a second control electrode (422) that cooperate with the common electrode (411). The first control electrode (421) corresponds to the transmission area (401), and the second control electrode (422) corresponds to the reflection area (402).

6. The liquid crystal display device according to claim 4, characterized in that, The quantum dot layer (20) is disposed on the side of the second substrate (42) facing the cholesteric liquid crystal layer (43); or, the quantum dot layer (20) is disposed between the backlight module (30) and the second substrate (42).

7. The liquid crystal display device according to any one of claims 1-6, characterized in that, The array substrate (12) has a metal wire grid polarizer (123) on the side facing the liquid crystal layer (13). The metal wire grid polarizer (123) is located on the light-emitting side of the quantum dot layer (20). The color filter substrate (11) has a polarizer (113) on it. The light transmission axis of the polarizer (113) is perpendicular to the light transmission axis of the metal wire grid polarizer (123).

8. The liquid crystal display device according to claim 7, characterized in that, The array substrate (12) has a pixel electrode (122) and a common electrode (121) that cooperates with the pixel electrode (122) on the side facing the liquid crystal layer (13). The metal wire grid polarizer (123) is reused as the pixel electrode (122) or the common electrode (121). And / or, the surface of the metal wire grid polarizer (123) facing the liquid crystal layer (13) is provided with an anti-reflection layer (124), the metal wire grid polarizer (123) includes a plurality of parallel and spaced metal traces, and the anti-reflection layer (124) includes a plurality of parallel and spaced light-absorbing traces, the light-absorbing traces corresponding one-to-one with the metal traces.

9. The liquid crystal display device according to claim 7, characterized in that, A quarter-wave plate (114) is provided on the color filter substrate (11). The quarter-wave plate (114) is located on the side of the polarizer (113) facing the liquid crystal layer (13). The fast and slow axes of the quarter-wave plate (114) are at 45° to the light transmission axis of the polarizer (113).

10. An electronic device, characterized in that, Includes the liquid crystal display device as described in any one of claims 1-9.

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