Display configuration having a substrate with reduced optical

Abstract

A liquid crystal display (LCD) includes a liquid crystal layer between a first substrate layer and a second substrate layer extending between the liquid crystal layer and a light guide plate, wherein each of the first substrate layer and the second substrate layer has a transmittance in a range of about 88% to about 99.5% for light having a wavelength of about 400 nm to about 650 nm and a distance of about 0.5 mm.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims the benefit of priority under the patent law to U.S. Provisional Application Serial No. 63 / 604,266, filed on November 30, 2023, the content of which is relied upon herein and incorporated herein by reference in its entirety. Technical Field

[0003] This disclosure generally relates to display configurations, and more particularly to display configurations with substrates having reduced optical transmittance. Background Art

[0004] Features desired by consumers for liquid crystal displays (LCDs) include narrow bezels and high contrast ratios. A typical LCD includes a liquid crystal (LC) display panel and a backlight unit (BLU), which can be, for example, direct - lit or edge - lit. The light provided by the BLU is spatially modulated by the LC display panel to produce a display image.

[0005] However, due to light leakage from the edges of the LC layer, the bezels may undesirably widen. Additionally, the guided light coupled into the LC layer from one pixel may scatter out from the front display surface at other pixels, thus reducing the contrast ratio of the display. Therefore, improvements are needed to narrow the bezels of LCDs and increase the contrast ratio of LCDs. Summary of the Invention

[0006] Embodiments disclosed herein include a liquid crystal display (LCD). The LCD includes a liquid crystal layer located between a first substrate layer and a second substrate layer, and the second substrate layer extends between the liquid crystal layer and a light guide plate. Each of the first substrate layer and the second substrate layer has a transmittance in the range of about 88% to about 99.5% for light having a wavelength of about 400 nanometers to about 650 nanometers and a distance of about 0.5 millimeters.

[0007] Additional features and advantages of the embodiments disclosed herein will be set forth in the detailed description below, and in part will be apparent to those of ordinary skill in the art from the description, or may be recognized by practicing the embodiments of the disclosure described herein, including the detailed description below, the claims, and the drawings.

[0008] It should be understood that the embodiments given in the foregoing general description and the following detailed description are intended to provide an overview or framework for understanding the nature and characteristics of the claimed embodiments. The inclusion of the drawings is for further understanding, and the drawings are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the present disclosure and, together with the specification, are used to explain the principles and operations of the present disclosure. Description of the Drawings

[0009] Figure 1 is a schematic side cross-sectional perspective view of a side-lit liquid crystal display (LCD);

[0010] Figure 2 is a schematic side cross-sectional perspective view of a side-lit LCD at least partially surrounded by a light detector;

[0011] Figure 3 is Figure 2 a schematic front or top perspective view of the side-lit LCD of

[0012] Figure 4 is Figure 2 a schematic illustration of the output light distribution of the front or top of the side-lit LCD of

[0013] Figure 5 is Figure 2 a schematic illustration of the output light distribution at the edge of the side-lit LCD of

[0014] Figure 6 is a graph showing the relationship between the edge light leakage percentage and the scattering factor of a side-lit LCD;

[0015] Figure 7 is a schematic side cross-sectional perspective view of another side-lit LCD at least partially surrounded by a light detector;

[0016] Figure 8 is Figure 7 a schematic front or top perspective view of the side-lit LCD of

[0017] Figure 9 is Figure 7 a schematic illustration of the output light distribution of the front or top of the side-lit LCD of

[0018] Figure 10 is Figure 7 a schematic illustration of the output light distribution at the edge of the side-lit LCD of

[0019] Figure 11A and Figure 11B is a graph showing the relationship between the front light power reduction and the edge light leakage reduction and the scattering factor of a side-lit LCD; and

[0020] Figure 12A and Figure 12B is a graph showing the relationship between the front light power reduction and edge leakage reduction of a side-light type LCD and glass transmittance. Detailed implementation manners

[0021] Now, reference will be made in detail to the currently preferred embodiments of the present disclosure, examples of which are shown in the accompanying drawings. In any possible case, the same reference numerals in all the drawings will be used to represent the same or similar parts. However, the present disclosure can be implemented in many different forms and should not be construed as limited to the embodiments set forth herein.

[0022] Ranges may be expressed herein as from “about” a particular value and / or to “about” another particular value. When expressing such ranges, another embodiment includes from the said one particular value and / or to the said another particular value. Similarly, when a value is expressed as an approximation by use of the antecedent “about”, it is to be understood that the particular value forms another embodiment. It should also be understood that each end value of a range is significant relative to the other end value and independent of the other end value.

[0023] Directional terms used herein (e.g., up, down, right, left, front, back, top, bottom) refer only to the drawings as drawn and are not intended to imply absolute orientation.

[0024] Unless otherwise expressly stated, in no way is any method set forth herein to be construed as requiring that the steps of the method be performed in a particular order, nor is any apparatus to be construed as requiring a particular orientation. Accordingly, where a method claim does not actually recite an order to be followed by the steps of the method, or any apparatus claim does not actually recite an order or orientation of the various components, or where the claims or specification do not otherwise specifically state that the steps are limited to a particular order, or do not recite an order or orientation of the apparatus components, in no way is it desired to infer an order or orientation in any respect. This applies to any possible non-explicit basis of interpretation, including: logical issues regarding step arrangement, operational flow, component order or component orientation; simple meaning derived from grammatical organization or punctuation; and the number or type of embodiments described in the specification.

[0025] As used herein, unless the context clearly indicates otherwise, the singular forms “a”, “an” and “the” include plural referents. Thus, for example, unless the context clearly indicates otherwise, a reference to “a” component includes aspects having two or more such components.

[0026] As used herein, the term "light transmittance" refers to the proportion of light (e.g., at a specified wavelength) incident on a material or layer that passes through the material or layer (e.g., within a specified travel distance through the material or layer) rather than being absorbed into the material or layer.

[0027] As used herein, the term "scattering factor" refers to the standard deviation (in degrees) of the surface light scattering characteristics.

[0028] As used herein, the term "rough surface" means that, as known to those of ordinary skill in the art, the roughness of the substrate surface measured by atomic force microscopy (AFM) is higher than that of the rest of the substrate surface.

[0029] Figure 1 is a schematic side cross-sectional perspective view of a side-lit liquid crystal display (LCD) 100. The LCD 100 includes a liquid crystal layer 102 sandwiched between a first color filter or thin film transistor (TFT) layer 108A and a second color filter or thin film transistor (TFT) layer 108B. These layers are located between a first substrate layer 104A and a second substrate layer 104B. A first polarizer 110A is positioned along the side of the first substrate layer 104A opposite the first color filter or TFT layer 108A, and a second polarizer 110B is positioned along the side of the second substrate layer 104B opposite the second color filter or TFT layer 108B. At least one optical film 112 is located between the second polarizer 110B and a light guide plate 106, and the light guide plate 106 includes a plurality of light extraction features 116. A reflector 114 extends near the bottom or back side of the light guide plate 106. The light guide plate 106 is side-lit, i.e., light is coupled to a light source 150 extending along the edge of the light guide plate 106. The light source 150 may include, for example, a plurality of light emitting diodes (LEDs).

[0030] In operation, light from the light source 150 is guided into the light guide plate 106 and further propagates through the various layers of the LCD, including at least one optical film 112, the second polarizer 110B, the second substrate layer 104B, the second color filter or TFT layer 108B, the liquid crystal layer 102, the first color filter or TFT layer 108A, the first substrate layer 104A, and the first polarizer 110A.

[0031] Figure 2 and Figure 3 respectively show a schematic side cross-sectional perspective view and a front or top perspective view of a side-lit LCD 200 at least partially surrounded by a light detector. Specifically, Figure 2FIG. 0 shows a schematic side cross-sectional perspective view of a side-lit LCD 200 that includes a liquid crystal layer 202 located between a first substrate layer 204A and a second substrate layer 204B, and the second substrate layer 204B extends between the liquid crystal layer 202 and a light guide plate 206. The light guide plate 206 includes a plurality of light extraction features (microstructures) 216. The light guide plate 206 is side-lit, i.e., light is coupled to a light source 250 that extends along an edge of the light guide plate 206. The light source 250 can include, for example, a plurality of light emitting diodes (LEDs). A Lambertian reflector 214 with a reflectivity of 100% extends near the bottom or back side of the light guide plate 206, while a specular reflector 218 with a reflectivity of 100% extends near an output edge of the light guide plate 206.

[0032] Each of the first substrate layer 204A and the second substrate layer 204B includes a glass composition that has a thickness of about 0.2 mm and a light transmittance of about 99.8% at a wavelength of 550 nm and a distance of about 0.5 mm (i.e., the distance that light travels through the substrate). The main surface of the second substrate layer 204B facing the liquid crystal layer 202 has a scattering factor (σ) of 2.03 degrees, which can be introduced by a color filter and / or a thin film transistor (TFT) layer in the LCD.

[0033] As Figure 2 shown, the front or top surface of the first substrate layer 204A faces a first light detector 500A, an input edge surface 220 faces a second light detector 500B, and an output edge surface 226 faces a third light detector 500C. Additionally, as Figure 3 shown, a left edge surface 222 faces a fourth light detector 500D, and a right edge surface 224 faces a fifth light detector 500E. The light detectors 500A to 500E are each configured to measure the light distribution transmitted through the corresponding facing surfaces of the LCD 200.

[0034] Figure 4 and Figure 5 respectively show schematic diagrams of the modeled output light distribution (detected by the light detectors 500A to 500E) of the front or top and edges of the side-lit LCD 200, where Figure 2 the shaded scale on the right represents an incoherent irradiance from 0.00 to 1.80. As can be seen from Figure 4 and Figure 4 and Figure 5 the output light varies according to the position within the top surface of the first substrate layer 204A and along the edge surfaces 220, 222, 224, and 226. Specifically, a certain amount of light output is observed from the edge surfaces 220, 222, 224, and 226, particularly from the edge surfaces 222 and 224 (left edge and right edge).

[0035] The light scattering characteristics of the surface related to surface roughness can be described by a Gaussian scattering function:

[0036]

[0037] where θ is the angle (degrees) relative to the specular reflection direction, I(θ) is the irradiance in the θ direction, I 0 is the radiance in the specular reflection direction, and the scattering factor σ is the standard deviation of the Gaussian distribution, in degrees.

[0038] Figure 6 is a graph showing the relationship between the modeled edge light leakage percentage and the scattering factor (σ) of the edge-lit LCD. Each edge-lit LCD has first and second substrate layers (listed as first and second substrate layers A, B, and C in Table 1) with different light transmittance levels at 550 nm, as summarized in Table 1.

[0039] Table 1

[0040]

[0041] Specifically, for the first and second substrate layers with light transmittances of 99.8%, 96%, and 88% respectively (e.g., first and second substrate layers 204A and 204B), Figure 6 shows the modeled light leakage (which is the percentage of the total possible light transmission through these surfaces) from the edge surfaces of these substrate layers (e.g., Figures 3 to 5 the edge surfaces 220, 222, 224, and 226 shown in Figure 2 in relation to the scattering factor (σ) of the main surface of the substrate facing the liquid crystal layer and extending between the liquid crystal layer and the light guide plate (e.g.,

[0042] the scattering factor (σ) of the main surface of the second substrate layer 204B facing the liquid crystal layer 202 shown in Figure 6 It can be seen that the higher the light transmittance of the substrate, the more serious the edge surface light leakage phenomenon. The higher the scattering factor (σ) of the main surface of the substrate facing the liquid crystal layer and extending between the liquid crystal layer and the light guide plate, the more serious the edge surface light leakage phenomenon. In other words, as Figure 6 shown, the reduction of the substrate light transmittance along the entire scattering factor range results in the reduction of the edge surface light leakage.

[0043] The scattering factor (σ) as described above may correspond to the surface roughness of the main surface of the substrate, which may be introduced on the substrate by a color filter and / or a thin film transistor (TFT) layer in an LCD. For example, techniques known to those of ordinary skill in the art may be used to roughen the main surface of the substrate, including but not limited to chemical and / or mechanical surface roughening. Such roughening may be performed so that the scattering factor (σ) of a given surface can be within an expected value or range.

[0044] Figure 7 and Figure 8 respectively show a schematic side cross-sectional perspective view and a front or top perspective view of a side-lit LCD 300 at least partially surrounded by light detectors. Specifically, Figure 7 shows a schematic side cross-sectional perspective view of a side-lit LCD 300, which includes a liquid crystal layer 302 located between a first substrate layer 304A and a second substrate layer 304B, and the second substrate layer 304B extends between the liquid crystal layer 302 and a light guide plate 306. The light guide plate 306 includes a plurality of light extraction features (microstructures) 316. The light guide plate 306 is side-lit, that is, light is coupled to a light source 350 extending along the edge of the light guide plate 306. The light source 350 may include, for example, a plurality of light emitting diodes (LEDs). A Lambertian reflector 314 with a reflectivity of 100% extends near the bottom or back side of the light guide plate 306, while a specular reflector 318 with a reflectivity of 100% extends near the output edge of the light guide plate 306.

[0045] Each of the first substrate layer 304A and the second substrate layer 304B includes a glass composition with a thickness of about 0.2 mm and a light transmittance of about 96% at a wavelength of 550 nm and a distance of about 0.5 mm (i.e., the light travel distance through the substrate). The main surface of the second substrate layer 304B facing the liquid crystal layer 302 has a scattering factor (σ) of 2.03 degrees.

[0046] As Figure 7 shown, the front or top surface of the first substrate layer 304A faces a first light detector 500A, the input edge surface 320 faces a second light detector 500B, and the output edge surface 326 faces a third light detector 500C. In addition, as Figure 8 shown, the left edge surface 322 faces a fourth light detector 500D, and the right edge surface 324 faces a fifth light detector 500E. The light detectors 500A to 500E are each configured to measure the light distribution transmitted through the corresponding facing surfaces of the LCD 300.

[0047] Figure 9 and Figure 10 respectively show Figure 7Schematic illustration of the modeled output light distribution (detected by light detectors 500A to 500E) on the front or top and edges of the edge-lit LCD 300, where Figure 9 The shaded scale on the right represents the incoherent irradiance from 0.00 to 1.80. From Figure 9 and Figure 10 it can be seen that the output light varies according to the position within the top surface of the first substrate layer 304A and along the edge surfaces 320, 322, 324, and 326. Specifically, compared with Figure 4 the edge surfaces 220, 222, 224, and 226, significantly less light output is observed from Figure 10 the edge surfaces 320, 322, 324, and 326.

[0048] Figure 11A and Figure 11B are graphs showing the relationship between the front light power reduction and edge light leakage reduction of the edge-lit LCD and the scattering factor (σ) of the main surface of the second substrate layer. Specifically, Figure 11A shows the relationship between the front light power reduction of the edge-lit LCD and the scattering factor (σ), where the light transmittance of the substrate of the edge-lit LCD is 88% and 96% at a wavelength of 550 nm and a distance (i.e., the light travel distance through the substrate) of approximately 0.5 mm. Figure 11B then shows the relationship between the edge light leakage reduction of the edge-lit LCD and the scattering factor (σ), where the light transmittance of the substrate of the edge-lit LCD is 88% and 96% at a wavelength of 550 nm and a distance (i.e., the light travel distance through the substrate) of approximately 0.5 mm.

[0049] From Figure 11A it can be seen that within the entire range of scattering factors shown in Figure 11A , for the edge-lit LCD with a substrate having a light transmittance of 88%, the front light power reduction is greater than that of the LCD with a substrate having a light transmittance of 96%. And, from Figure 11B it can be seen that within the entire range of scattering factors shown in Figure 11B , for the edge-lit LCD with a substrate having a light transmittance of 88%, the edge light leakage reduction is greater than that of the LCD with a substrate having a light transmittance of 96%.

[0050] Figure 12A and Figure 12B are graphs showing the relationship between the front light power reduction and edge light leakage reduction of the edge-lit LCD and the glass transmittance. Specifically, Figure 12A shows the relationship between the front light power reduction at a wavelength of 550 nm and a distance (i.e., the light travel distance through the substrate) of approximately 0.5 mm and the glass light transmittance of the substrate. Figure 12Bshows the relationship between the edge leakage reduction and the light transmission of the substrate glass at a wavelength of 550 nanometers and a distance (i.e., the light traveling distance through the substrate) of about 0.5 millimeters.

[0051] From Figure 12A it can be seen that along Figure 12A the entire range of substrate glass light transmission shown, the front light power reduction decreases linearly with the increase in substrate glass light transmission. And, from Figure 12B it can be seen that along Figure 12B the entire range of substrate glass light transmission shown, the edge leakage reduction increases asymptotically with the decrease in substrate glass light transmission.

[0052] Embodiments disclosed herein include embodiments in which the LCD includes a liquid crystal layer located between a first substrate layer and a second substrate layer, and the second substrate layer extends between the liquid crystal layer and the light guide plate. Each of the first substrate layer and the second substrate layer has a light transmittance range of about 88% to about 99.5%, for example about 92% to about 96%, for light with a wavelength of about 400 nanometers to about 650 nanometers and a distance (i.e., the light traveling distance through the substrate) of about 0.5 millimeters.

[0053] Such embodiments may also include embodiments in which each of the first substrate layer and the second substrate layer has a thickness in the range of about 0.1 millimeters to about 1 millimeter, for example about 0.2 millimeters to about 0.5 millimeters.

[0054] Such embodiments may also include embodiments in which the LCD is a direct - lit or edge - lit type. In addition, such embodiments may include embodiments in which the light guide plate includes a plurality of light extraction features.

[0055] Embodiments disclosed herein include embodiments in which each of the first substrate layer and the second substrate layer includes glass, including embodiments in which the first substrate layer and the second substrate layer consist essentially of glass. For example, embodiments disclosed herein include embodiments in which the substrate comprises a glass composition, such as an alkali - free glass composition, the glass composition comprising 58 to 65 weight percent (wt%) of SiO 2 、14 to 20 wt% of Al 2 O 3 、8 to 12 wt% of B 2 O 3 、1 to 3 wt% of MgO, 5 to 10 wt% of CaO, and 0.5 to 2 wt% of SrO. The substrate may also include a glass composition, such as an alkali - free glass composition, the glass composition comprising 58 to 65 wt% of SiO 2 、16 to 22 wt% of Al 2 O 3 、1 to 5 wt% of B 2O 3 and 1 to 4 wt% of MgO, 2 to 6 wt% of CaO, 1 to 4 wt% of SrO, and 5 to 10 wt% of BaO. Additionally, the substrate may comprise a glass composition, such as an alkali-free glass composition, the glass composition comprising 57 to 61 wt% of SiO 2 and 17 to 21 wt% of Al 2 O 3 and 5 to 8 wt% of B 2 O 3 and 1 to 5 wt% of MgO, 3 to 9 wt% of CaO, 0 to 6 wt% of SrO, and 0 to 7 wt% of BaO. The substrate may further comprise a glass composition, such as an alkali-containing glass composition, the glass composition comprising 55 to 72 wt% of SiO 2 and 12 to 24 wt% of Al 2 O 3 and 10 to 18 wt% of Na 2 O, 0 to 10 wt% of B 2 O 3 and 0 to 5 wt% of K 2 O, 0 to 5 wt% of MgO, and 0 to 5 wt% of CaO, and in certain embodiments, the glass composition may further comprise 1 to 5 wt% of K 2 O and 1 to 5 wt% of MgO.

[0056] In certain exemplary embodiments, the glass may comprise at least one dopant or colorant capable of reducing the light transmittance of the glass, as is known to those of ordinary skill in the art. Such embodiments include those in which the dopant or colorant does not adversely affect the color transmittance of the glass, for example by preferentially transmitting or absorbing at least one RGB color relative to at least one other red, green, or blue (RGB) color.

[0057] The embodiments disclosed herein include methods of manufacturing the LCDs disclosed herein and electronic devices comprising the LCDs disclosed herein.

[0058] The embodiments disclosed herein may also, for example, enable the production of LCDs with narrower borders and higher contrast.

[0059] It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments of the present disclosure without departing from the spirit and scope of the present disclosure. Accordingly, it is intended that the present disclosure cover the modifications and variations provided they come within the scope of the appended claims and the equivalents of those claims.

Claims

1. A liquid crystal display (LCD), comprising: a liquid crystal layer, the liquid crystal layer being located between the first substrate layer and the second substrate layer, the second substrate layer extending between the liquid crystal layer and the light guide plate; Each of the first substrate layer and the second substrate layer has a transmittance ranging from about 88% to about 99.5% for light having a wavelength of about 400 nanometers to about 650 nanometers and a distance of about 0.5 millimeters.

2. The LCD of claim 1, wherein each of the first substrate layer and the second substrate layer has a transmittance ranging from about 92% to about 96% for light having a wavelength of about 400 nanometers to about 650 nanometers and a distance of about 0.5 millimeters. 3 . The LCD of claim 1 , wherein each of the first substrate layer and the second substrate layer has a thickness ranging from about 0.1 mm to about 1 mm.

4. The LCD as claimed in claim 1, wherein the light guide plate is an edge-lit type.

5. The LCD of claim 1, wherein the light guide plate comprises a plurality of light extraction features. 6 . The LCD of claim 1 , wherein each of the first substrate layer and the second substrate layer comprises glass.

7. The LCD of claim 1, wherein the glass includes at least one dopant or colorant.

8. A method of manufacturing the LCD as claimed in claim 1.

9. An electronic device comprising the LCD according to claim 1.

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