Description:RUGGEDIZED LIQUID CRYSTAL DISPLAY AND A PROCESS OF MAKING THE SAME

BACKGROUND

TECHNICAL FIELD
[0001] The present disclosure relates to the field of ruggedized display technology and particularly relates to a Ruggedized Liquid Crystal Display (RLCD) panel and a process for manufacturing the same to enhance durability and performance in harsh environments.

DESCRIPTION OF THE RELATED ART
[0002] Liquid Crystal Display (LCD) technology is widely used in various applications, including defense, aerospace, medical, industrial and outdoor environments, where displays must operate under extreme conditions. However, conventional LCD panels are highly susceptible to environmental stressors, which can significantly degrade their performance, reliability and lifespan. One of the primary challenges faced by LCD panels is low-temperature operation. In extremely cold environments, such as high-altitude aircraft, military operations in sub-zero conditions, or medical applications requiring cryogenic exposure, LCD panels exhibit slower response times, loss of contrast and eventual freezing of the liquid crystal material. This degradation renders the display unreadable and unusable in critical situations.
[0003] Additionally, high-altitude environments pose another set of challenges. At reduced atmospheric pressure, internal stresses within the LCD panel increase, leading to potential structural failures, condensation-related issues and long-term performance degradation. Conventional LCD panels lack the necessary reinforcement to withstand such extreme altitudes. Another major issue encountered with conventional LCDs is intense sunlight exposure. In outdoor applications such as cockpit displays, military vehicle dashboards and industrial monitoring screens, excessive ambient light causes significant glare and reflection losses, making the display difficult to read. This not only affects usability but also compromises safety in mission-critical applications.
[0004] Furthermore, electromagnetic interference (EMI) and electromagnetic compatibility (EMC) issues are significant concerns for LCD panels used in high-electronic-density environments, such as military control systems, avionics and medical imaging equipments. Conventional LCDs are highly susceptible to electromagnetic interference, which can distort display output, introduce unwanted artifacts, or cause complete display failure in sensitive environments. Mechanical durability is another critical aspect that standard LCD panels fail to address. Conventional LCDs are prone to EMI/EMC, mechanical impact, vibrations and shock-related failures, particularly in defense, aerospace and rugged industrial applications. Accidental impacts, equipment drops, or sustained mechanical stress can lead to panel breakage, delamination, or internal component failure, rendering the display non-functional. Moreover, dust, moisture and contaminants further threaten the longevity and performance of LCD panels. In harsh industrial or battlefield environments, particles and moisture can infiltrate display layers, leading to optical degradation, electrical failures and long-term damage. Conventional LCDs lack sufficient protection against such external contaminants, making them unsuitable for extreme operational conditions.
[0005] Therefore, there is a need for a display system capable of withstanding extreme environmental conditions while maintaining optimal performance and durability and also overcoming the above-mentioned drawbacks.
[0006] The reference to any prior art in this specification is not an acknowledgment or suggestion that prior art forms part of the common general knowledge in any jurisdiction or that a person skilled in the art could reasonably expect that prior art to be understood, regarded as relevant and/or combined with other aspects of prior art.

BRIEF SUMMARY
[0007] One or more embodiments are directed to a Ruggedized Liquid Crystal Display (RLCD) panel and a process for manufacturing the same to ensure enhanced durability, improved optical performance and resistance to harsh environmental conditions, including low temperatures, high altitudes, intense sunlight, electromagnetic interference (EMI) and mechanical impacts.
[0008] An embodiment of the present disclosure relates to the RLCD panel. The RLCD panel includes an LCD panel for visual output. A front surface of the LCD panel is bonded to an Anti-Reflective and Electromagnetic Interference (AR-EMI) shielding glass. In an embodiment, the conductive side of the AR-EMI shielding glass faces the LCD panel, reducing internal reflection losses and shielding the display from electromagnetic interference. To ensure low-temperature operability, an Indium Tin Oxide (ITO) heater glass is bonded to a back surface of the LCD panel. In some embodiments, the ITO heater glass has a sheet resistance range in between 20-50 Ohm/square, allowing the RLCD panel to function at temperatures as low as -55°C by providing uniform heating and thereby preventing the display from freezing.
[0009] In an embodiment, the RLCD panel includes a bonding structure utilizing Very High Bond (VHB) tape. The VHB tape is applied along the edges of the surface of the LCD panel to bond with the AR-EMI shielding glass and ITO heater glass. This 300- 500 micron-thick VHB tape serves as mechanical reinforcement while creating a designated space for subsequent gel filling. To enhance the structural integrity, the RLCD panel includes a sealing layer comprising an adhesive material, such as TSE397B, that is applied along all the bonded edges of the RLCD panel while leaving an opening of 6 - 10 mm at the feed point for gel injection. The adhesive material prevents light leakage and provides additional mechanical strength to the RLCD. In an embodiment, the RLCD panel includes a first Optically Clear Gel (OCG) layer (108A) injected between the LCD panel and the AR-EMI shielding glass and a second OCG layer (108B) is injected between the LCD panel and the ITO heater glass. The first OCG layer and the second OCG layer consist of a two-part gel mixture, composed of Part-A gel and Part-B gel in a mass ratio in the range between 1:1.5 to 1:1.7, ensuring proper cross-linking, uniform encapsulation and structural reinforcement.
[0010] In an embodiment, the RLCD panel includes a sealant, such as TSE397B, applied, after curing of the first OCG layer and the second OCG layer, to the feed point to prevent light leakage, moisture infiltration, dust accumulation and environmental contamination.
[0011] The RLCD panel ensures EMI shielding and superior optical performance, making the RLCD panel ideal for defense, medical and industrial applications. By incorporating AR-EMI shielding, ITO heater, optically clear gel encapsulation and a robust sealing mechanism, the RLCD panel provides a long-lasting, reliable display system capable of enduring extreme environmental conditions while maintaining optimal functionality and visual clarity.
[0012] An embodiment of the present disclosure relates to the process of making the Ruggedized Liquid Crystal Display (RLCD) panel to withstand harsh environmental conditions by incorporating optical, electrical, thermal and structural reinforcements. The process begins with bonding a front surface of an LCD panel to an Anti-Reflective and Electromagnetic Interference (AR-EMI) shielding glass. Such configuration reduces reflection losses and shields the display from electromagnetic interference, ensuring stable performance in EMI-prone environments such as military, aerospace and industrial applications.
[0013] Next, a back surface of the LCD panel is bonded with a transparent Indium Tin Oxide (ITO) coated heater glass. The outer surface of the ITO heater glass is coated with AR- material index matched to air and the inner surface (the surface facing towards LCD panel) of the ITO heater glass is non-coated. Such bonding facilitates uniform heat distribution and allows backlight to enter into an LCD panel to ensure the LCD panel remains visually functional in low-temperature conditions. In an embodiment, the ITO heater glass has a sheet resistance of 20-50 Ohm/square, allowing the RLCD panel to maintain functionality at temperatures as low as -55°C. To reinforce the mechanical integrity of the RLCD panel, a bonding structure utilizing Very High Bond (VHB) tape is applied along the edges of the LCD panel, AR-EMI shielding glass and ITO heater glass. The VHB tape has a thickness of approximately 300- 500 microns. Such thickness ensures sufficient space to accommodate subsequent optical gel filling for displays of different sizes while securing bonding between the LCD glass and the ITO heater glass and between the LCD glass and the AR-EMI glass. In some embodiments, a designated feed point is left unbonded for controlled gel injection in later stages of the process.
[0014] Following the bonding process, a sealing layer comprising an adhesive material, such as TSE397B, is applied along the bonded edges of the RLCD panel. The sealing material enhances structural integrity while maintaining an opening at the feed point, allowing for the injection of an Optically Clear Gel (OCG) layer. In an embodiment, the OCG layer is formed by injecting an optically clear gel mixture through the feed point. The gel is uniformly distributed using a controlled air pressure system within a range of 5-70 PSI, ensuring even filling without air bubbles. The OCG layer optimizes optical performance by improving image quality of the display and impact resistance and durability under high-impact and high-vibration conditions. In an embodiment, the OCG layer consists of a two-part gel mixture, composed of Part-A gel and Part-B gel in a mass ratio in the range between 1:1.5 to 1:1.7. Further, the OCG layer ensures proper cross-linking, consistent viscosity and structural reinforcement.
[0015] Next, the RLCD panel undergoes a curing process to stabilize its adhesive and bonding properties. The first curing phase is conducted at room temperature (250C- 150C) for a predefined duration of 24- 36 hours, allowing the adhesives and gel to settle. The second curing phase is performed at an elevated temperature of 85°C for 4- 6 hours, further strengthening the bonding structure and mechanical durability. After curing, the feed point is sealed using a contamination-resistant adhesive, such as TSE397B, to prevent moisture infiltration, light leakage, dust accumulation and environmental contamination. In some embodiments, the feed point is a 6- 10 mm gap, allowing for controlled gel injection.
[0016] By integrating optical shielding, EMI shielding, thermal management, impact resistance and environmental protection mechanisms, this manufacturing process ensures that the RLCD panel meets durability standards for defense, aerospace, medical and industrial applications. The resulting ruggedized display provides long-term operational reliability, high optical performance and resistance to extreme environmental conditions.
[0017] The features and advantages of the subject matter here will become more apparent in light of the following detailed description of selected embodiments, as illustrated in the accompanying FIGUREs. As will be realized, the subject matter disclosed is capable of modifications in various respects, all without departing from the scope of the subject matter. Accordingly, the drawings and the description are to be regarded as illustrative in nature.

BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In the figures, similar components and/or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label with a second label that distinguishes among the similar components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label.
[0019] FIGURE 1 illustrates a side view of a Ruggedized Liquid Crystal Display (RLCD) panel, in accordance with an embodiment of the present disclosure.
[0020] FIGURE 2 illustrates the LCD panel with a Very High Bond (VHB) tape without liner, in accordance with an embodiment of the present disclosure.
[0021] FIGURE 3 illustrates an Anti-Reflective and Electromagnetic Interference (AR-EMI) shielding glass, in accordance with an embodiment of the present disclosure.
[0022] FIGURE 4A illustrates a transparent Indium Tin Oxide (ITO) heater glass with heater wires, in accordance with an embodiment of the present disclosure.
[0023] FIGURE 4B illustrates the ITO heater glass with the VHB tape without the liner, in accordance with an embodiment of the present disclosure.
[0024] FIGURE 5 illustrates a process of making the RLCD panel, in accordance with an embodiment of the present disclosure.
[0025] Other features of embodiments of the present disclosure will be apparent from accompanying drawings and detailed description that follows.
DETAILED DESCRIPTION
[0026] Terminology
[0027] Brief definitions of terms used throughout this application are given below.
[0028] The terms “connected” or “coupled” and related terms are used in an operational sense and are not necessarily limited to a direct connection or coupling. Thus, for example, two devices may be coupled directly, or via one or more intermediary media or devices. As another example, devices may be coupled in such a way that information can be passed there between, while not sharing any physical connection with one another. Based on the disclosure provided herein, one of ordinary skill in the art will appreciate a variety of ways in which connection or coupling exists in accordance with the aforementioned definition.
[0029] If the specification states a component or feature “may”, “can”, “could”, or “might” be included or have a characteristic, that particular component or feature is not required to be included or have the characteristic.
[0030] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context dictates otherwise.
[0031] The phrases “in an embodiment,” “according to one embodiment,” and the like generally mean the particular feature, structure, or characteristic following the phrase is included in at least one embodiment of the present disclosure and may be included in more than one embodiment of the present disclosure. Importantly, such phrases do not necessarily refer to the same embodiment.
[0032] Exemplary embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments are shown. This disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. These embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the disclosure to those of ordinary skill in the art. Moreover, all statements herein reciting embodiments of the disclosure, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future (i.e., any elements developed that perform the same function, regardless of structure).
[0033] Certain exemplary embodiments of the present invention are described below and illustrated in the accompanying figures. The embodiments described are only for purposes of illustrating the present invention and should not be interpreted as limiting the scope of the invention, which, of course, is limited only by the claims below. Other embodiments of the invention and certain modifications and improvements of the described embodiments, will occur to those skilled in the art and all such alternate embodiments, modifications and improvements are within the scope of the present invention.
[0034] According to common practice, the various features of the drawings discussed below are not necessarily drawn to scale. Dimensions of various features and elements in the drawings may be expanded or reduced to more clearly illustrate the embodiments of the invention.
[0035] One or more embodiments are directed to a Ruggedized Liquid Crystal Display (RLCD) panel and a process for manufacturing the same to ensure enhanced durability, improved optical performance and resistance to harsh environmental conditions, including low temperatures (such as, -55 degree Celsius), low pressure (such as, 66000ft high altitude), intense sunlight, electromagnetic interference (EMI) and mechanical impacts. The RLCD panel may include an LCD panel for visual output with an Anti-Reflective and Electromagnetic Interference (AR-EMI) shielding glass, bonded to a front surface of the LCD panel. The conductive surface of the AR-EMI shielding glass faces the LCD panel to reduce reflection losses and shield against electromagnetic interference. Further, a transparent Indium Tin Oxide (ITO) heater glass may be bonded to a back surface of the LCD panel with the AR-EMI shielding glass to provide uniform heating for operation in low-temperature environments. Furthermore, a bonding structure, comprising VHB tape may be applied along the edges of the LCD panel, the AR-EMI shielding glass and the ITO heater glass to form bonded edges of the RLCD panel, leaving a designated feed point for subsequent gel filling. The RLCD panel may include a sealing layer, comprising an adhesive material applied to the bonded edges of the RLCD panel to enhance structural integrity while leaving an opening at the feed point for gel injection. Further, the RLCD may include an Optically Clear Gel (OCG) layer, disposed between the LCD panel, and the AR-EMI shielding glass and between the LCD panel and the ITO heater glass. The OCG layer is formed by injecting a gel mixture through the feed point and uniformly distributing it using a controlled air pressure system to enhance optical transmission and impact resistance. Additionally, the RLCD panel may include a contamination-resistant seal to seal, upon curing, the feed point to prevent environmental contamination, ensuring long-term durability of the RLCD panel.
[0036] FIGURE 1 illustrates a side view of the RLCD panel 100, in accordance with an embodiment of the present disclosure. In an embodiment, the RLCD panel 100 may be operated reliably in harsh environmental conditions, including low temperatures, intense sunlight, high-altitude atmospheres and EMI/EMC-prone environments, by incorporating a multi-layered structure designed for enhanced optical performance, thermal stability, mechanical durability and electromagnetic shielding. As illustrated, the RLCD panel 100 may include a Liquid Crystal Display (LCD) panel 102 that forms the primary display layer for visual output. Bonded to one surface of the LCD panel 102 may be an Anti-Reflective and Electromagnetic Interference (AR-EMI) shielding glass 104, which is oriented such that its conductive surface faces toward the LCD panel 102. The AR-EMI shielding glass layer 104 may serve to reduce surface reflection losses and shield the display from electromagnetic disturbances, making the RLCD panel 100 suitable for use in electromagnetically noisy environments such as defense and aerospace systems.
[0037] In an embodiment, on the opposite surface of the LCD panel 102, a transparent Indium Tin Oxide (ITO) heater glass 106 may be bonded to the structure. The ITO heater glass 106 may provide uniform heating across the LCD panel 102, facilitating the RLCD panel 100 to function effectively even in extremely low temperatures. The integration of the ITO heater layer 106 may ensure that the liquid crystal elements within the LCD panel 102 remain responsive and do not freeze under sub-zero conditions. Additionally, Optically Clear Gels (OCGs) may be disposed between the layers of the RLCD panel 100 to improve optical transmission and mechanical impact resistance. A first OCG layer 108A may fill the interfacial spaces between the LCD panel 102, the AR-EMI shielding glass 104 and a second OCG layer 108B may fill the interfacial spaces between the LCD panel 102 and the ITO heater glass 106, helping to eliminate internal reflections and air gaps, while simultaneously absorbing mechanical shock. In an embodiment, the first OCG layer 108A and the second OCG layer 108B may enhance optical performance by reducing air-to-glass interface reflection losses and improve impact resistance by the impulse action of the first OCG layer 108A and the second OCG layer 108B. In an embodiment, the LCD panel 102 may be configured to have dimensions larger than those of the AR-EMI shielding glass layer 104 and the ITO heater glass 106.
[0038] In an embodiment, the RLCD panel 100 may be constructed using layered bonding and sealing structures, including high-strength adhesive and tape components, to ensure mechanical robustness and long-term environmental resistance. While the individual components of the RLCD panel 100 are illustrated in FIGURE 1, their structure, material properties, bonding configuration and role in the ruggedization process will be described in greater detail in the following paragraphs.
[0039] FIGURE 2 illustrates the LCD panel 102 with a Very High Bond (VHB) tape 204 without liner, in accordance with an embodiment of the present disclosure. FIGURE 2 may correspond to the initial step of the ruggedization process, focusing on panel handling, peripheral bonding preparation and feed point allocation, which are fundamental to achieving mechanical strength, optical clarity and long-term environmental stability. In an embodiment, Display Head Assembly (DHA) may be dismantled and the LCD panel 102 may be taken out and pasted with a piece of Kapton tape on the LCD tab to insulate both the de-soldering points where negative and positive terminals of backlight were connected. During dismantling, care must be taken to keep the LCD panel 102 carefully on light box and switch on the light box and then drive the LCD panel 102 to check the LCD panel for any damage and also ensure the following: should be driven properly; no patch, crack or scratch; no hot pixel or dead pixel; no pixel column or pixel row missing; and no dust or dirt.
[0040] In an embodiment, the LCD panel 102 is shown in isolation before any ruggedizing layers are applied. It may be noted that, without departing from the scope of the disclosure, the LCD panel 102 may be selected from a variety of commercially available or custom display modules, including but not limited to, TFT-LCDs, monochrome LCDs, or high-resolution active-matrix displays, depending on the end application. In certain embodiments, the LCD panel 102 may incorporate protective coatings or anti-fingerprint layers on its surface. The LCD panel 102 may include a flexible display connector 202, which may serve as an electrical interface between the LCD module and an external driving or control unit. Additionally, a removable protection sheet may be applied over the display surface to safeguard it from scratches, static discharge, or particulate contamination during assembly and handling. This protective film may be composed of PET, vinyl, or other dielectric transparent materials and is typically removed before final lamination.
[0041] In an embodiment, the VHB tape 204 may vary in thickness, width and adhesive properties based on factors such as panel size, environmental sealing requirements and mechanical stress thresholds. In some embodiments, the VHB tape 204 may be composed of acrylic foam or other viscoelastic adhesives providing both cushioning and strong adhesion between subsequent layers. The VHB tape 204 may be in a full rectangular perimeter or partial side-bonded layout, depending on the bonding strategy. At an initial stage, the VHB tape 204 may retain the liner, typically made from silicone-coated paper or plastic film, which protects the adhesive surface prior to use. Importantly, a feed point 208 is deliberately left open, unbonded, or tape-free at one location along the edge. The feed point 208 may facilitate the later-stage injection of OCG, which serves both optical and mechanical functions within the RLCD structure. In a specific embodiment, the LCD panel 102 may be kept on the Laminar Flow Table (LFT) keeping viewing surface up, then 1st piece of VHB tape having width range 2- 5 mm may be pasted along the bottom length side (contains LCD TAB) of the LCD panel 102, then 2nd piece of VHB tape may be pasted along the top length side, then 3rd piece of VHB tape may be pasted along the left width and then 4th piece of VHB tape may be pasted along the right width side of LCD panel 102. Further, it may be ensured that there is no overlapping of the VHB tape 204 to avoid thickness variation. While applying the VHB tape 204, leave a 6- 10 mm gap for the feed point 208 at a top location along the edge of the LCD panel 102.
[0042] In an embodiment, the LCD panel 102, after removal of the liner, leaves behind the exposed adhesive surface of the VHB tape, as shown by 206. The exposed VHB tape 204 may enable direct bonding with other structural layers of the RLCD panel, such as an AR-EMI shielding glass or an ITO heater glass, which are aligned and laminated in subsequent steps. The removal of the liner may ensure maximum adhesion strength at the bonding interface. In various embodiments, the VHB tape 204 may be selectively patterned to create micro-channels for air escape or gel flow, or it may be layered in multiple strips to tailor compression resistance and thermal expansion handling. The feed point 208 may remain preserved during this stage to allow a seamless flow of gel material into the internal cavity formed between the panel layers. It may be apparent to a person skilled in the art that such steps accommodate a wide variety of display formats, bonding strategies and environmental sealing approaches, enabling the RLCD panel to be tailored to different use cases ranging from high-altitude avionics displays to field-deployable medical monitors and defense-grade computing interfaces.
[0043] FIGURE 3 illustrates an Anti-Reflective and Electromagnetic Interference (AR-EMI) shielding glass 104, in accordance with an embodiment of the present disclosure. In an embodiment, referring to FIGURE 3, the AR-EMI shielding glass 104 may be shown independently before being bonded to the LCD panel 102. The AR-EMI shielding glass 104 may be formed from soda-lime glass, aluminosilicate glass, or chemically-strengthened glass, depending on application-specific durability requirements. In some embodiments, the AR-EMI shielding glass 104 may be coated with a transparent conductive layer, such as Indium Tin Oxide (ITO), to serve the dual function of EMI shielding and optical enhancement. This conductive coating is positioned on the inner surface, i.e., the side facing the LCD panel 102 when assembled, to allow effective grounding and EMI suppression. In an embodiment, the ITO-coated soda glass may have a sheet resistance of less than 10.0 Ohm/sqr to enhance EMI shielding effect in the range of 2 MHz- 40 GHz without degrading any optical clarity and performance.
[0044] In an embodiment, the AR-EMI shielding glass 104 may include a blackened silver conductive mesh to achieve similar electromagnetic interference (EMI) shielding functionality. The silver conductive coating may be applied as a thin metallic layer or in the form of a patterned mesh or nanowire network and may be positioned on the inner surface of the AR-EMI shielding glass 104, i.e., the surface facing the LCD panel 102, when assembled. Such configurations facilitate effective electrical grounding while providing high conductivity for EMI suppression and may also support optical transmission depending on the thickness and pattern/mesh of the blackened silver coating.
[0045] In an embodiment, the AR-EMI shielding glass 104 may include multi-layer anti-reflective coatings optimized for specific wavelength bands to improve visibility under direct sunlight and reduce surface glare. In further embodiments, the AR-EMI shielding glass 104 may be laminated with additional films for shatter resistance, UV filtering, or abrasion protection, thereby enabling its use in diverse environments such as military vehicles, cockpit instrumentation, or rugged outdoor terminals. Before coupling the AR-EMI shielding glass 104 with the LCD panel 102, the AR-EMI shielding glass 104 may be inspected visually to ensure the following: no fingerprint; no dust particles or dirt; no scratch or crack; and identify the viewing/index matched to air surface (mega ohm or open) and conducting (few ohms) surface using multimeter. In an embodiment, the AR-EMI shielding glass 104 may be bonded to the LCD panel 102, forming a layered subassembly of the RLCD panel 100. The bonding is typically achieved using VHB tape 204. The feed point 208, previously left open in the VHB tape layout, is preserved to facilitate gel injection, as discussed in detail in the following paragraphs. The LCD connector 202 may remain accessible, extending from the bonded assembly to allow electrical interfacing. Such a bonded configuration may improve the structural rigidity of the panel while providing EMI protection, reduced reflectivity and enhanced mechanical impact resistance. In some embodiments, the bonding interface between the AR-EMI shielding glass 104 and LCD panel 102 may be reinforced using optically clear adhesive (OCA) or reworkable gel films in lieu of or in addition to VHB tape. The choice of bonding material may depend on thermal expansion tolerance and ease of repair. It may be apparent to a person skilled in the art that the configuration shown in the FIGURE(s) here may be scalable and adaptable to a variety of display sizes and form factors and is suitable for integration into ruggedized computing systems, avionics panels, wearable display modules, or field-deployable instrumentation.
[0046] In an embodiment, the conductive side of the AR-EMI shielding glass 104 face includes two surfaces consisting of bare (non-coated) glass surfaces. A first surface of the AR-EMI shielding glass 104 is adjacent to the first OCG layer 108A, having a refractive index close to glass to facilitate reduction of internal reflection losses at the interface of glass and gel, hence improving display image quality. In an embodiment, a second surface of the AR-EMI shielding glass 104, present above the 1st conducting coating layer, includes two thin film coating layers, including a first film coating and a second film coating. The first film coating may have a sheet resistance less than 10 ohms per square and may depend on the required shielding effectiveness in the particular range of electromagnetic frequency emitted by the LCD display and absorbed from the outside environment. The first film coating may shield the display from electromagnetic interference. The second film coating may have an anti-reflection index matching the index of air to optimize optical performance in the presence of sunlight.
[0047] FIGURE 4A illustrates the transparent Indium Tin Oxide (ITO) heater glass 106 with heater wires, in accordance with an embodiment of the present disclosure. FIGURE 4B illustrates the ITO heater glass 106 with the VHB tape 204 without the liner, in accordance with an embodiment of the present disclosure. For the sake of brevity, FIGURES 4A and 4B have been explained together. FIGURES 4A and 4B may depict the progressive integration of bonding structures and feed point definition, enabling the heater glass 106 to be securely assembled with other display layers while providing thermal functionality under extreme environmental conditions.
[0048] In an embodiment, referring to FIGURE 4A, the ITO heater glass 106 may be shown independently, including associated electrical structures. The ITO heater glass 106 may be fabricated from optically clear soda-lime or borosilicate glass, coated with a uniform layer of Indium Tin Oxide (ITO) to form a transparent, electrically conductive surface. This surface enables uniform heat generation across the display when powered, preventing issues such as crystal freezing or display lag in low-temperature environments. In some embodiments, the sheet resistance of the ITO heater glass 106 may be optimized for defrosting without compromising transparency and range between 20 - 50 Ohm/sqr, depending upon the size and aspect ratio of the display screen and temperature of the operating environment. Further, the ITO heater may facilitate the RLCD panel to function at temperatures as low as -55°C by providing uniform heating and thereby preventing Liquid Crystal (LC) materials of the LCD panel from freezing.
[0049] In an embodiment, the ITO heater glass 106 includes heating electrodes 402A and 402B coupled to heater wires 404A and 404B, which may extend to a power interface or controller and may be routed externally or embedded depending on space constraints and environmental sealing requirements. In an embodiment, the ITO heater glass 104 may be inspected visually to ensure no fingerprints, no dust particles or dirt and no scratches or cracks.
[0050] In an embodiment, the heater glass 106 is prepared for bonding by the application of VHB tape 204 around its periphery. The VHB tape 204 is used to bond the ITO heater glass 106 with other structural layers in the RLCD assembly, including the LCD panel 102 and AR-EMI shielding glass 104. The VHB tape 204 is initially covered with a liner, which protects the adhesive surface during positioning and alignment. In this stage, a feed point 208 is deliberately left unsealed by the tape, providing a channel for the later-stage injection of an OCG between the bonded layers. The VHB tape 204 may be made from acrylic foam or high-performance elastomers with customizable thickness (300 ~ 500 microns) to accommodate the gel cavity while maintaining mechanical stability. In a specific embodiment, the ITO heater glass 106 may be kept on the LFT in such a way that the heater wires 404A and 404B will remain on the bottom surface and then 1st piece of VHB tape with 2- 5 mm width may be pasted along the bottom length side (contains connecting terminals of heater wires) of Heater glass, 2nd piece of VHB tape may be pasted along the top length side, 3rd piece of VHB tape may be pasted along the left width and 4th piece of VHB tape may be pasted along the right width side of the ITO heater glass 106. It may be apparent to a person skilled in the art to make sure that there is no overlapping of the VHB tape 204 to avoid thickness variation. While applying the VHB tape 204, a 6 - 10 mm gap may be left for the feed point 208 at top corner of the ITO Heater glass 106.
[0051] In an embodiment, referring to FIGURE 4B, the VHB tape liner may be removed, exposing the active adhesive surface, referred to as the VHB tape 204 without liner, as shown by 206. Such surface allows the ITO heater glass 106 to be securely bonded to the LCD panel 102 or other intermediate layers during ruggedized assembly. The adhesive surface of the VHB tape 204 may provide not only mechanical adhesion but also vibration damping and thermal expansion flexibility, which are critical in harsh deployment environments such as aircraft cockpits, armored vehicles and industrial control panels. Further, the feed point 208 may remain preserved to ensure that the gel can be injected precisely and distributed evenly in subsequent steps.
[0052] In an embodiment, the AR-EMI shielding glass 104 may be positioned at the bottom and the ITO heater glass 106 disposed on the top, covering the back side of the display stack. In this embodiment, the LCD panel 102 is sandwiched between the two functional glass layers. Such a configuration may be preferred in applications where back-surface heating is advantageous, for example, to maintain the LCD panel’s operating temperature in extremely cold environments by heating from behind. The first OCG layer 108A and the second OCG layer 108B (hereafter together referred to as OCG layer 108) may be visible and may be disposed between the layers to provide optical clarity, mechanical cushioning and uniform bonding. The heater electrodes 402A and 402B may be near the edges of the ITO heater glass 106 and the heater wires 404A and 404B extend toward the system power interface. The feed point 208 may be accessible and positioned along the periphery of the assembly to allow controlled injection of the optically clear gel.
[0053] In an embodiment, the AR-EMI shielding glass 104 is disposed on top, forming the outermost visible surface of the display and the ITO heater glass 106 is positioned at the bottom, behind the LCD panel 102. This configuration may be particularly suited for use cases where EMI shielding and anti-reflective performance are very critical, such as in outdoor displays or cockpit instrumentation, where sunlight readability and signal integrity are essential. Placing the AR-EMI shielding glass 104 at the top ensures first-line protection against electromagnetic interference and surface glare while maintaining structural strength. Further, the ITO heater glass 106 at the bottom may continue to serve its role in regulating the temperature of the LCD panel 102 from the rear. The LCD connector 202 and heater wires 404A and 404B remain accessible for electrical interfacing. It may be apparent to a person skilled in the art that, depending on environmental exposure, user visibility requirements and system integration constraints, the relative placement of the AR-EMI shielding 104 and the ITO heater layer 106 can be customized without departing from the scope of the disclosure. The modular nature of the assembly, combined with robust bonding, gel encapsulation and environmental sealing, enables the RLCD panel 100 to adapt across defense, aerospace, medical and industrial applications while ensuring long-term durability and high-performance display characteristics. In an embodiment, the RLCD assembly may include a bonded LCD panel 102 mounted on a zig fixture. The RLCD panel represents the subassembly comprising the LCD panel 102, the AR-EMI shielding glass 104 and the ITO heater glass 106 bonded together with the peripheral VHB tape 204, as previously illustrated in earlier figures. As discussed in previous paragraphs, the feed point 208 is preserved at a specific location on the bonded structure to enable precise gel injection. In order to fill the gel, a gel mixture is dispensed into the RLCD panel through a dispensing barrel, which is mounted vertically above the feed point 208. The barrel may be pre-filled with the prepared gel mixture and connected to an air pressure device for controlled dispensing. The dispensing system enables pressure-driven flow of the OCG material through the feed point 208 into the bonded interfacial cavities of the RLCD panel.
[0054] In an embodiment, the gel mixture may be prepared by combining Part-A gel with Part-B gel, maintaining a precise mass ratio of 1:1.5 - 1:1.7, of OCG required to fill both front and back surfaces of the RLCD panel. The two-part gel ensures high optical performance in high ambient light and enhanced impact resistance. The two-part gel components are thoroughly mixed for 10- 15 minutes, followed by filtration through a MESH #300 filter to eliminate particulate contaminants. The filtered gel mixture is then degassed in a vacuum chamber for at least 10- 20 minutes, depending on the volume of the gel, to eliminate entrapped air bubbles that could compromise optical or structural integrity. The degassed gel is loaded into a 55 ml barrel fitted with a green PPF 18GA nozzle suitable for precision injection. The RLCD panel is secured onto the fixture, ensuring a stable and angled orientation for gel flow. A light box, which is kept just back side of the LCD panel 102, is switched on to visually monitor the OCG for proper filling progression.
[0055] The gel is dispensed through the feed point 208 by gradually increasing air pressure from the air pressure device in a controlled range of 5 - 70 PSI, ensuring smooth, void-free gel injection. The gel mixture may be injected through the feed point via an IVF needle. The gel is first dispensed between the ITO heater glass 106 and the LCD panel 102 and subsequently through the feed point 208 between the AR-EMI shielding glass 104 and the LCD panel 102, depending on panel orientation and cavity structure.
[0056] In an embodiment, after the gel filling is completed, the RLCD 100 may be removed from the fixture and laid flat on a surface to allow settling at room temperature (250C- 150C) for 24- 36 hours for uniform thickness OCG layer formation. It is then transferred to an oven for thermal curing at 85°C for 4- 6 hours, facilitating full cross-linking and adhesion of the gel. Upon curing, the feed point 208 may be cleaned using isopropyl alcohol (IPA) and a lint-free cloth and sealed with the sealant (such as TSE397B adhesive), which is then cured at room temperature for 3- 5 hours to complete the encapsulation process.
[0057] In an embodiment, the second OCG layer 108B may be formed in the space between the LCD panel and the ITO heater glass. The RLCD assembly is then dismantled from the OCG dispensing fixture and kept horizontally on a flat surface for 24-36 hours at room temperature (250C- 150C) for uniform thickness OCG layer 108B formation. Similar steps are performed for the formation of the first OCG 108A, between the LCD panel and AR-EMI glass. Such steps facilitate achieving uniform thickness OCG layers 108, which eventually improve the uniform optical performance throughout the display screen. The RLCD panel assembly may then be kept inside the oven at an elevated temperature of 85°C for 4- 6 hours for curing the OCG layers 108. The finalized RLCD panel 100 may finally be placed in a protective storage box to prevent contamination or damage before deployment.
[0058] FIGURE 5 illustrates a process 500 of making the RLCD panel, in accordance with an embodiment of the present disclosure. The process starts at step 502.
[0059] At first, a front surface of an LCD panel may be bonded to an Anti-Reflective and Electromagnetic Interference (AR-EMI) shielding glass, at step 504. Further, the conductive side of the AR-EMI shielding glass faces the LCD panel. This configuration reduces reflection losses and shields the display from electromagnetic interference, ensuring stable performance in EMI-prone environments such as military, aerospace and industrial applications.
[0060] Next, at step 506, a back surface of the LCD panel with the AR-EMI shielding glass is bonded to a transparent Indium Tin Oxide (ITO) heater glass, which facilitates uniform heat distribution to ensure the LCD panel remains functional in low-temperature conditions. In an embodiment, the ITO heater glass has a sheet resistance of 20-50 Ohm/sqr, allowing the RLCD panel to maintain uninterrupted functionality at temperatures as low as -55°C, without freezing Liquid Crystal (LC) materials of the LCD panel. In an embodiment, the AR-EMI shielding glass comprises ITO-coated soda glass with a sheet resistance of less than 10.0 Ohm/sqr to enhance EMI shielding effect in the range of 2 MHz- 40 GHz without degrading any optical clarity and performance. In an embodiment, to reinforce the mechanical integrity of the RLCD panel, a bonding structure utilizing Very High Bond (VHB) tape is applied along the edges of the LCD panel, AR-EMI shielding glass and ITO heater glass, at step 508. The VHB tape has a thickness of approximately, 300- 500 microns, ensuring sufficient space to accommodate subsequent optical gel filling while securing the bonded layers. In some embodiments, a designated feed point is left unbonded for controlled gel injection in later stages of the process.
[0061] Following the bonding process, a sealing layer including an adhesive material is applied, at step 510, along the bonded edges of the RLCD panel. The adhesive material may be TSE397B, which may prevent light leakage and provide additional mechanical strength. The sealing material enhances structural integrity while maintaining an opening at the feed point, allowing for the injection of an Optically Clear Gel (OCG) layer. In an embodiment, the OCG layer is formed, at step 512, by injecting an optically clear gel mixture through the feed point. The gel is uniformly distributed using a controlled air pressure system within a range of 5-70 PSI, ensuring even filling without air bubbles. This OCG layer enhances optical performance and impact resistance, improving the panel’s image quality and durability under high-impact and high-vibration conditions. In certain embodiments, the OCG layer consists of a two-part gel mixture, composed of Part-A and Part-B in a mass ratio of 1:1.5 - 1:1.7, ensuring consistent viscosity and structural reinforcement. Further, the two-part gel mixture ensures high optical performance in high ambient light and enhanced impact resistance. In an embodiment, a first OCG layer is formed between the LCD panel, the AR-EMI shielding glass and a second OCG layer is formed between the LCD panel and the ITO heater glass. The first OCG layer and the second OCG layer are formed by injecting the gel through the feed point and uniformly distributing using a controlled air pressure system to enhance optical transmission performance and impact resistance.
[0062] Next, at step 514, the RLCD panel undergoes a curing process to stabilize its adhesive and bonding properties. The first curing phase is conducted at room temperature (250C- 150C) for a predefined duration of 24- 36 hours, allowing the adhesives and gel to settle. The second curing phase is performed at an elevated temperature of 85°C for 4- 6 hours, further strengthening the bonding structure and mechanical durability. After curing, the feed point is sealed, at step 516, using a contamination-resistant adhesive, such as TSE397B, to prevent moisture infiltration, dust accumulation and environmental contamination. In some embodiments, the feed point is a 6- 10 mm gap, allowing for controlled gel injection and effective post-curing sealing. The method ends at step 518.
[0063] By integrating optical shielding, thermal management, impact resistance and environmental protection mechanisms, this manufacturing process ensures that the RLCD panel meets durability standards for defense, aerospace, medical and industrial applications. The resulting ruggedized display system provides long-term operational reliability, high optical clarity and resistance to extreme environmental conditions.
[0064] While embodiments of the present disclosure have been illustrated and described, it will be clear that the disclosure is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions and equivalents will be apparent to those skilled in the art, without departing from the spirit and scope of the disclosure, as described in the claims.
[0065] It should be apparent to those skilled in the art that many more modifications besides those already described are possible without departing from the inventive concepts herein. The inventive subject matter, therefore, is not to be restricted except in the spirit of the appended claims. Moreover, in interpreting both the specification and the claims, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms “comprises” and “comprising” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced. Where the specification claims refer to at least one of something selected from the group consisting of A, B, C …. and N, the text should be interpreted as requiring only one element from the group, not A plus N, or B plus N, etc.
[0066] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions, or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art. , Claims:I/We Claim:
1. A Ruggedized Liquid Crystal Display (RLCD) panel (100) to withstand harsh environments, the RLCD panel (100) comprising:
an LCD panel (102) for visual output;
an Anti-Reflective and Electromagnetic Interference (AR-EMI) shielding glass (104), bonded to a front surface of the LCD panel (100), wherein the conductive surface of the AR-EMI shielding glass (104) faces the LCD panel (102) to reduce reflection losses and shield against electromagnetic interference;
a transparent Indium Tin Oxide (ITO) heater glass (106), bonded to a back surface of the LCD panel (102) with the AR-EMI shielding glass (104), to provide uniform heating for uninterrupted operation of the RLCD panel in low-temperature environments;
a bonding structure, comprising Very High Bond (VHB) tape (204) applied along edges of the LCD panel (102), the AR-EMI shielding glass (104) and the ITO heater glass (106) to form bonded edges of the RLCD panel (100), leaving a designated feed point (208) for subsequent gel filling;
a sealing layer, comprising an adhesive material applied to the bonded edges of the RLCD panel (100) to enhance structural integrity while leaving an opening at the feed point (208) for gel injection;
a first Optically Clear Gel (OCG) layer (108A) between the LCD panel (102) and the AR-EMI shielding glass (104) and a second OCG layer (108B) between the LCD panel (102) and the ITO heater glass (106), wherein the first OCG layer (108A) and the second OCG layer (108B) are formed by injecting the gel through the feed point (208) and uniformly distributing it using a controlled air pressure system; and
a sealant (802) to seal, upon curing, the feed point to prevent environmental contamination, light leakage and ensure long-term durability of the RLCD panel (100).
2. The RLCD panel (100) as claimed in claim 1,
wherein the AR-EMI shielding glass (104) comprises ITO-coated soda glass with a sheet resistance of less than 10.0 Ohm/sqr to enhance EMI shielding effect in the range of 2 MHz- 40 GHz without degrading any optical clarity and performance;
wherein the ITO heater glass (106) has a sheet resistance of 20-50 Ohm/sqr to maintain LCD functionality, without freezing Liquid Crystal (LC) materials of the LCD panel (102), at low temperature up to -55°C; and
wherein the VHB tape (204) has a thickness between 300 - 500 microns to provide space for containing the first OCG layer between the LCD panel (102) and the AR-EMI shielding glass (104) and the second OCG layer between the LCD panel (102) and the ITO heater glass (106).
3. The RLCD panel (100) as claimed in claim 1, wherein the first OCG layer (108A) and the second OCG layer (108B) are composed of a two-part gel mixture, comprising Part-A and Part-B gel in the range of 1:1.5 to 1:1.7 mass ratio, ensuring high optical performance in high ambient light and enhanced impact resistance.
4. The RLCD panel (100) as claimed in claim 1, wherein the gel injection process utilizes air pressure within a range of 5-70 PSI, ensuring even gel distribution without air bubbles trapping.
5. The RLCD panel (100) as claimed in claim 1, wherein the sealant includes TSE397B adhesive and the feed point (208) of a 6-10 mm gap for controlled gel injection.
6. A process of making a Ruggedized Liquid Crystal Display (RLCD) panel to withstand harsh environments, the process comprising:
bonding a front surface of an LCD panel with an Anti-Reflective and Electromagnetic Interference (AR-EMI) shielding glass to reduce reflection losses and shield against electromagnetic interference;
bonding a back surface of the LCD panel with the AR-EMI shielding glass, to a transparent Indium Tin Oxide (ITO) heater glass to provide uniform heating for uninterrupted operation in low-temperature environments;
applying Very High Bond (VHB) tape along the edges of the LCD panel, the AR-EMI shielding glass and the ITO heater glass to form bonding edges of the RLCD panel, leaving a designated feed point, for providing space for subsequent gel filling;
applying a sealing layer to the bonded edges of the RLCD panel to enhance structural integrity while leaving an opening at the feed point for gel injection;
forming a first Optically Clear Gel (OCG) layer between the LCD panel and the AR-EMI shielding glass and a second OCG layer between the LCD panel and the ITO heater glass, wherein the first OCG layer and the second OCG layer are formed by injecting a gel through the feed point and uniformly distributing using a controlled air pressure system;
curing the RLCD panel through:
a first curing phase at room temperature for a first predefined duration; and
a second curing phase at a predefined elevated temperature for a second predefined duration to achieve stable adhesion and mechanical durability; and
sealing, after curing, the feed point using a sealant to prevent light leakage, environmental contamination and ensuring long-term durability of the RLCD panel.
7. The process as claimed in claim 6,
wherein the AR-EMI shielding glass comprises ITO-coated soda glass with a sheet resistance of less than 10.0 Ohm/sqr to enhance EMI shielding effect in the range of 2 MHz- 40 GHz without degrading any optical clarity and performance;
wherein the ITO heater glass has a sheet resistance of 20- 50 Ohm/sqr to maintain LCD functionality, without freezing the Liquid Crystal (LC) materials of the LCD panel (102), at low temperature up to -55°C;
wherein the VHB tape has a thickness of between 300- 500 microns to provide space for containing the first OCG layer between the LCD panel and the AR-EMI shielding glass and the second OCG layer between the LCD panel and the ITO heater glass.
8. The process as claimed in claim 6,
wherein the first OCG layer and the second OCG layer are composed of a two-part gel mixture, comprising Part-A and Part-B in the range of 1:1.5 to 1:1.7 mass ratio, ensuring high optical performance in high ambient light and enhanced impact resistance; and
wherein the gel injection process utilizes air pressure within a range of 5-70 PSI, ensuring even gel distribution without air bubbles trapping.
9. The process as claimed in claim 6, wherein the first predefined duration is 24- 36 hours, the second predefined duration is 4- 6 hours and a predefined elevated temperature is 85°C.
10. The process as claimed in claim 6, wherein the sealant includes TSE397B adhesive and the feed point of a 6- 10 mm gap for controlled gel injection.