Patent Publication Number: US-2015062498-A1

Title: Liquid crystal lens and liquid crystal display apparatus having the same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority under 35 U.S.C. §119 to Korean Patent Application No. 10-2013-0105256, filed on Sep. 3, 2013 in the Korean Intellectual Property Office (KIPO), the disclosure of which is incorporated by reference herein in its entirety. 
     TECHNICAL FIELD 
     Exemplary embodiments of the present invention relate to liquid crystal display, and more specifically, to a liquid crystal lens and a liquid crystal display apparatus having the same. 
     DISCUSSION OF THE RELATED ART 
     A liquid crystal lens uses a specific arrangement of liquid crystal molecules to function like an optical lens. The liquid crystal molecules may be rotated in an undesired direction by an electric field between fine patterns formed in the liquid crystal lens, and therefore, the response speed of the liquid crystal molecules may be reduced. 
     SUMMARY 
     In accordance with an exemplary embodiment of the present invention, a liquid crystal lens includes a first substrate, a second substrate, a liquid crystal layer, and an alignment layer. 
     The first substrate includes a plurality of electrodes. The second substrate faces the first substrate. The liquid crystal layer is disposed between the first substrate and the second substrate. The liquid crystal layer includes liquid crystal molecules and a mesogen. The alignment layer is disposed between the liquid crystal layer and the first substrate or between the liquid crystal layer and the second substrate. The mesogen includes an acrylate functional group. The acrylate functional group contacts the liquid crystal layer and prevents a flow of the liquid crystal molecules. 
     In an exemplary embodiment of the present invention, the alignment layer may include a first alignment layer disposed between the liquid crystal layer and the first substrate, and a second alignment layer disposed between the liquid crystal layer and the second substrate. 
     In an exemplary embodiment of the present invention, the alignment layer may include polyimide. 
     In an exemplary embodiment of the present invention, the liquid crystal lens may further include an insulation layer disposed on the plurality of electrodes. 
     In an exemplary embodiment of the present invention, different voltages from each other may be applied to the electrodes, respectively. 
     In an exemplary embodiment of the present invention, the voltages may be in a range from about 0V to about 10V. 
     In an exemplary embodiment of the present invention, the plurality of electrodes each may have a stripe shape. 
     In an exemplary embodiment of the present invention, a pre-tilted angle of the liquid crystal molecules adjacent to the mesogen may be equal to or less than 10°. 
     In an exemplary embodiment of the present invention, the liquid crystal lens may further include a first polarizing plate and a second polarizing plate. The first polarizing plate may be disposed on a lower surface of the first substrate. The second polarizing plate may be disposed on an upper surface of the second substrate. 
     In an exemplary embodiment of the present invention, the liquid crystal lens may further include a sealant. The sealant may be disposed on each of two opposite ends of the first substrate and the second substrate. The sealant may seal the liquid crystal layer. 
     In accordance with an exemplary embodiment of the present invention, a liquid crystal display apparatus includes a liquid crystal lens and a display panel. 
     The liquid crystal lens includes a first substrate, a second substrate, a liquid crystal layer, and an alignment layer. The first substrate includes a plurality of electrodes. The second substrate faces the first substrate. The liquid crystal layer is disposed between the first substrate and the second substrate. The liquid crystal layer includes liquid crystal molecules and a mesogen. The alignment layer is disposed between the liquid crystal layer and the first substrate or between the liquid crystal layer and the second substrate. The mesogen includes an acrylate functional group. The acrylate functional group contacts the liquid crystal layer and prevents a flow of the liquid crystal molecules. 
     The display panel is disposed on a lower surface of the liquid crystal lens 
     In an exemplary embodiment of the present invention, the alignment layer may include a first alignment layer disposed between the liquid crystal layer and the first substrate and a second alignment layer disposed between the liquid crystal layer and the second substrate. 
     In an exemplary embodiment of the present invention, the alignment layer may include polyimide. 
     In an exemplary embodiment of the present invention, the liquid crystal lens may further include an insulation layer disposed on the electrodes. 
     In an exemplary embodiment of the present invention, different voltages from each other may be applied to the plurality of electrodes, respectively. 
     In an exemplary embodiment of the present invention, the voltages may be in a range from about 0V to about 10V. 
     In an exemplary embodiment of the present invention, the plurality of electrodes each may have a stripe shape. 
     In an exemplary embodiment of the present invention, a pre-tilted angle of the liquid crystal molecules adjacent to the mesogen may be equal to or less than 10°. 
     In an exemplary embodiment of the present invention, the liquid crystal lens may further include a first polarizing plate and a second polarizing plate. The first polarizing plate may be disposed on a lower surface of the first substrate. The second polarizing plate may be disposed on an upper surface of the second substrate. 
     In an exemplary embodiment of the present invention, the liquid crystal lens may further include a sealant. The sealant may be disposed on both ends of the first substrate and the second substrate. The sealant may seal the liquid crystal layer. According to an exemplary embodiment of the present invention, the weight of the mesogen may be in a range from about 0.1% by weight to about 1.0% by weight, with respect to the total weight of the liquid crystal layer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure will become more apparent by describing in detailed exemplary embodiments thereof with reference to the accompanying drawings, in which: 
         FIG. 1  is a perspective view illustrating a liquid crystal display apparatus in accordance with an exemplary embodiment of the present invention; 
         FIG. 2  is a cross-sectional view illustrating a liquid crystal lens as illustrated in  FIG. 1  in accordance with an exemplary embodiment of the present invention; 
         FIG. 3  is a cross-sectional view illustrating a liquid crystal lens as illustrated in  FIG. 2 , in which voltages are applied to electrodes, in accordance with an exemplary embodiment of the present invention; 
         FIG. 4  is a phase shift graph illustrating a phase of a liquid crystal lens as illustrated in  FIG. 3  in accordance with an exemplary embodiment of the present invention; and 
         FIGS. 5A to 5F  are cross-sectional views illustrating a method for manufacturing a liquid crystal lens in accordance with an exemplary embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The same reference numerals may be used to denote the same or substantially the same elements throughout the specification and the drawings. The inventive concept, however, may be modified in various different ways, and should not be construed as limited to the embodiments set forth herein. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be understood that when an element or layer is referred to as being “on,” “connected to,” “coupled to,” or “adjacent to” another element or layer, it can be directly on, connected, coupled, or adjacent to the other element or layer, or intervening elements or layers may be present. 
       FIG. 1  is a perspective view illustrating a liquid crystal display apparatus in accordance with an exemplary embodiment of the present invention.  FIG. 2  is a cross-sectional view illustrating a liquid crystal lens illustrated in  FIG. 1 , in accordance with an exemplary embodiment of the present invention.  FIG. 3  is a cross-sectional view illustrating a liquid crystal lens illustrated in  FIG. 2 , where voltages applie to electrodes, in accordance with an exemplary embodiment of the present invention.  FIG. 4  is a graph illustrating a phase shift of a liquid crystal lens as illustrated in  FIG. 3 , in accordance with an exemplary embodiment of the present invention. 
     A liquid crystal layer  300 , as illustrated in  FIG. 1 , includes liquid crystal molecules  310  and mesogens  320  which are not hardened. 
     A liquid crystal layer  300 , as illustrated in  FIG. 2 , includes liquid crystal molecules  310  and mesogens  320  which are hardened, with no electric field applied to the liquid crystal layer  300 . 
     A liquid crystal layer  300 , as illustrated in  FIG. 3 , includes liquid crystal molecules  310  and mesogens  320  which are hardened, with an electric field applied to the liquid crystal layer  300 . 
     Referring to  FIGS. 1 to 3 , a liquid crystal display apparatus includes a liquid crystal lens and a display panel. 
     The liquid crystal display apparatus includes a first substrate  100 , a second substrate  200 , a liquid crystal layer  300  and a display panel  600 . 
     The first substrate  100  includes a plurality of electrodes EL 1 , EL 2 , and EL 3 . The second substrate  200  faces the first substrate  100 . 
     The first substrate  100  and the second substrate  200  may be plastic substrates, formed of, e.g., kapton, polyethersulphone (PES), polycarbonate (PC), polyimide (PI), polyethyleneterephthalate (PET), polyethylenenaphthalate (PEN), polyacrylate (PAR), fiber reinforced plastic (FRP), etc Alternatively, the first substrate  100  and the second substrate  200  may be glass substrates. 
     An insulation layer  110  may be disposed on the electrodes EL 1 , EL 2 , and EL 3 . The insulation layer  110  electrically insulates the electrodes EL 1 , EL 2 , EL 3  from other elements. 
     The insulation layer  110  may be formed of an organic material or an inorganic material. Examples of the organic material and the inorganic material include a benzocyclobutene resin, an olefic resin, a polyimide resin, an acryl resin, a polyvinyl resin, a siloxane resin, a silicon resin, etc. 
     The display panel  600  may be a liquid crystal display (LCD) panel. Alternatively, the display panel  600  may be an electro luminescent display (ELD) panel, a field emission display (FED) panel, a surface-conduction electron-emitter display (SED) panel, a plasma display panel (PDP), a cathode ray tube (CRT) panel, an electrophoretic display (EPD) panel, etc. 
     Referring to  FIG. 2 , the liquid crystal lens may include a lens area LA and a non-lens area NLA. The electrodes EL 1 , EL 2 , and EL 3  are disposed on the lens area LA. The electrodes EL 1 , EL 2 , and EL 3  are spaced apart from each other. The liquid crystal layer  300  may be operated by the electrodes EL 1 , EL 2 , and EL 3 , and thus, the lens area LA may function as a lens. The electrodes EL 1 , EL 2 , and EL 3  may extend in a first direction D1. 
     A plurality of lines (not illustrated) spaced apart from each other may be formed in, e.g., the lens area LA. The lines may apply voltages to the electrodes EL 1 , EL 2 , and EL 3 . For example, the lines may extend in a second direction D2, which is substantially perpendicular to the first direction D1. 
     A pad part (not illustrated) may be formed on the non-lens area NLA, applying voltages to the electrodes EL 1 , EL 2 , and EL 3 . First edges of the lines (not illustrated) may extend to the pad part and the first edges may form line pad electrodes (not illustrated). 
     Different voltages from each other may be applied to the electrodes EL 1 , EL 2 , and EL 3 , respectively. The voltages applied to the electrodes may be in a range from about 0V to about 10V. 
     When a strong voltage is applied to an electrode, the liquid crystal molecules  310 , which are positioned adjacent to the electrode, may be arranged so that their major axes are substantially perpendicular to the first substrate  100 . However, when a weak or no voltage is applied to an electrode, an initial arrangement of the liquid crystal molecules  310 , which are positioned adjacent to the electrode, may be maintained. 
     The liquid crystal molecules  310  positioned adjacent to the electrode, which receives a strong voltage, may be aligned substantially perpendicular to the first substrate  100 . The liquid crystal molecules  310  positioned adjacent to the electrode, which receives a weak or no voltage, may be aligned substantially parallel with the first substrate  100 . 
     The electrodes EL 1 , EL 2 , and EL 3  may be shaped like stripes. The electrodes EL 1 , EL 2 , and EL 3  each may include a transparent conductor, such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide having a doped aluminum (AZO). For example, the electrodes EL 1 , EL 2 , and EL 3  each may have a slit pattern. 
     A sealant  350  may be disposed in the non-lens area NLA, sealing the liquid crystal layer  300 . The sealant  350  may be disposed on two opposite ends of the first substrate  100  and the second substrate  200 . 
     The liquid crystal lens may include a first alignment layer  120  disposed on an upper surface of the first substrate  100 . The liquid crystal lens may include a second alignment layer  210  disposed on a lower surface of the second substrate  200 . The first and second alignment layers  120  and  210  may pre-tilt the molecules in the liquid crystal layer  300 . 
     For example, the first alignment layer  120  and the second alignment layer  210  may be formed of an alignment material. For example, the alignment material may include polyimide (PI). The alignment material may be coated on the first substrate  100  and the second substrate  200 , and may be then dried, forming the first alignment layer  120  and the second alignment layer  210 . 
     The first alignment layer  120  and the second alignment layer  210  may be rubbed by using an aligning fabric or a roller. 
     For example, a rubbing direction of the first alignment layer  120  may be the first direction D1. A rubbing direction of the second alignment layer  210  may be a direction, which is tilted clockwise from the first direction D1 by about 5° to about 10°. 
     The alignment layers  120  and  210  may be omitted depending on the type of the liquid crystal layer or structures of the electrodes EL 1 , EL 2 , and EL 3 . For example, when the electrodes EL 1 , EL 2 , and EL 3  have micro-slits that enable the liquid crystal to have an initial alignment, the first and second alignment layers  120  and  210  may be omitted. Furthermore, when the liquid crystal lens includes a mesogen layer for an initial alignment, the alignment layers  120 ,  210  may be omitted. 
     The liquid crystal lens may include a first polarizing plate  400  and a second polarizing plate  500 . The first polarizing plate  400  may be disposed on a lower surface of the first substrate  100 . The second polarizing plate  500  may be disposed on an upper surface of the second substrate  200 . 
     For example, a polarization axis of the first polarizing plate  400  may be substantially perpendicular to the rubbing direction of the first alignment layer  120 . A polarization axis of the second polarizing plate  500  may be tilted clockwise from the rubbing direction of the second alignment layer  210  by about 80° to about 90°. Therefore, the liquid crystal lens may operate in an electrically controlled birefringence mode (ECB). 
     The liquid crystal layer  300  may be formed between the first substrate  100  and the second substrate  200 . The liquid crystal layer  300  may include liquid crystal molecules  310  and mesogens  320 . 
     An alignment of the liquid crystal molecules  310  may be controlled by an electric field, which is formed by voltages applied to the electrodes EL 1 , EL 2 , and EL 3 . Thus, the liquid crystal molecules  310  may be aligned to form a desired configuration. For example, different voltages from each other are applied to the electrodes EL 1 , EL 2 , and EL 3 , respectively, thus allowing the liquid crystal layer  300  to function as a lenticular lens having a semicylinder-shaped convex portion. 
     When no voltages are applied to the electrodes EL 1 , EL 2 , and EL 3 , a major axis of the liquid crystal molecules  310  is aligned substantially parallel with the first and second substrates  100  and  200 . The liquid crystal molecules  310  may be pre-tilted. 
     For example, the liquid crystal molecules  310  may be aligned in the rubbing direction of the first alignment layer  120 . The liquid crystal molecules  310  may be aligned in the first direction D1. 
     The liquid crystal molecules  310  adjacent to the second substrate  200  may be aligned corresponding to the rubbing direction of the second alignment layer  210 . The liquid crystal molecules  310  may be pre-tilted clockwise from the first direction D1 by about 10° or less. For example, the liquid crystal molecules  310  adjacent to the second substrate  200  may have a pre-tilted angle, which is equal to or less than about 10°. 
     When the liquid crystal molecules  310  are positioned in the middle portion of the first substrate  100  and the second substrate  200 , the major axis of the liquid crystal molecules  310  may be parallel with an upper surface of the first substrate  100 . The major axis of the liquid crystal molecules  310  may be aligned in the first direction D1. 
     The mesogens  320  may decrease a flow of the liquid crystal molecules  310  adjacent to the first substrate  100  and the second substrate  200 . 
     The mesogens  320  may be disposed adjacent to the first substrate  100  and the second substrate  200 . The mesogens  320  may be disposed between the liquid crystal molecules  310 , which are adjacent to the first substrate  100  and the second substrate  200 . 
     The mesogens  320  may be photo-cured. The mesogens  320  may be injected in a monomer state into the first substrate  100  and the second substrate  200 . After the injection, voltages may be applied to the electrodes EL 1 , EL 2 , and EL 3  and light, such as, e.g., ultraviolet (UV) rays, may be radiated to the mesogens  320 . Accordingly, the mesogen monomers may react with each other. Thus, the mesogens  320  may be rendered to be adjacent to the first substrate  100  and the second substrate  200 . 
     The mesogens  320  may assist in aligning the liquid crystal molecules  310 . The mesogens  320  may have a similar structure to the liquid crystal molecules  310 . 
     The mesogens  320  each have an aliphatic ring or an aromatic ring. The mesogens  320  each have a functional group at its terminal. The functional group may include a photoreactor. For example, the photoreactor may include an acrylate, a methacrylate, etc. 
     When light such as an ultraviolet ray is radiated to the mesogens  320 , a plurality of the mesogens  320  reacts with an initiator, forming an oligomer, polymer or a mixture thereof. 
     Therefore, the mesogens  320  may be adjacent to the first substrate  100  and the second substrate  200 , and the mesogens  320  may prevent a flow of the liquid crystal molecules  310 . The mesogens  320  may prevent the liquid crystal molecules  310  from rotating to the rubbing directions of the first alignment layer  120  and the second alignment layer  210 . 
     The weight of the mesogens  320  may be in a range from about 0.1% by weight to about 1.0% by weight, without the total weight of the liquid crystal composition. 
     When the amount of the mesogens  320  is equal to or less than about 0.1% by weight, with respect to the total weight of the liquid crystal composition, a high refraction liquid crystal may be difficult to control. When the amount of the mesogens  320  is greater than about 1.0% by weight, with respect to the total weight of the liquid crystal composition, the returning speed of a liquid crystal may be decreased, and thus, the response time of the liquid crystal display may be reduced. 
       FIG. 4  illustrates a phase shift of a liquid crystal as illustrated in  FIG. 3  in accordance with an exemplary embodiment of the present invention. 
     For example, a first voltage V1, which is a relatively smallest voltage, may be applied to a first electrode EL 1 . A second voltage V2, which is higher than the first voltage V1, may be applied to a second electrode EL 2 . A third voltage V3, which is higher than the second voltage V2, may be applied to a third electrode EL 3 . The third voltage V3, which is a relatively highest voltage, may be applied to a third electrode EL 3 . The first voltage V1 may be applied to the first electrode EL 1 , which corresponds to a convex portion of the lens. 
     The major axis of the liquid crystal molecules  310  adjacent to the electrode (e.g., third electrode EL 3 ), to which the highest voltage (e.g., third voltage V3) is applied, may be aligned to be substantially perpendicular to the first substrate  100 . The major axis of the liquid crystal molecules  310  adjacent to the electrode (e.g., first electrode EL 1 ), to which the smallest voltage (e.g., first voltage V1) is applied, may be aligned to be substantially parallel to the first substrate  100 . 
     The liquid crystal molecules  310  may be aligned according to electric fields generated by the voltages V1, V2, and V3 applied to the electrodes EL 1 , EL 2 , and EL 3 , respectively. Therefore, the liquid crystal molecules  310  may be aligned to have a lens shape. For example, different voltages from each other are applied to the electrodes EL 1 , EL 2 , and EL 3 , respectively, and thus, the liquid crystal layer  300  may function as a lenticular lens having a semicylinder-shaped convex portion. 
       FIGS. 5A to 5F  are cross-sectional views illustrating a method for manufacturing a liquid crystal lens in accordance with an exemplary embodiment of the present invention. 
     Referring to  FIG. 5A , a first substrate  100  and a second substrate  200  facing the first substrate  100  are prepared. A plurality of electrodes EL 1 , EL 2 , and EL 3  is formed on the first substrate  100 . 
     The electrodes EL 1 , EL 2 , and EL 3  may extend in a first direction D1. The electrodes EL 1 , EL 2 , and EL 3  may be shaped like stripes. The electrodes EL 1 , EL 2 , and EL 3  may include a transparent conductor, such as indium tin oxide (ITO), indium zinc oxide (IZO), or zinc oxide having a doped aluminum (AZO). For example, the electrodes EL 1 , EL 2 , and EL 3  each may have a slit pattern. 
     An insulation layer  110  may be formed on the first substrate  100  and the electrodes EL 1 , EL 2 , and EL 3 . 
     The insulation layer  110  may be formed of an organic material or an inorganic material. Examples of the organic material and the inorganic material include a benzocyclobutene resin, an olefic resin, a polyimide resin, an acryl resin, a polyvinyl resin, a siloxane resin, a silicon resin, etc. 
     Referring to  FIG. 5B , a first alignment layer  120  and a second alignment layer  210  may be formed on the first substrate  100  and the second substrate  200 , pre-tilting liquid crystal molecules in the liquid crystal layer  300 . 
     For example, the first alignment layer  120  and the second alignment layer  210  may be formed of an alignment material. The alignment material may be coated on the first substrate  100  and the second substrate  200 , and may be then dried, forming the first alignment layer  120  and the second alignment layer  210 . 
     The first alignment layer  120  and the second alignment layer  210  may be rubbed by using an aligning fabric or a roller. 
     For example, a rubbing direction of the first alignment layer  120  may be the first direction D1. A rubbing direction of the second alignment layer  210  may be a direction, which is tilted clockwise from the first direction D1 by about 5° to about 10°. 
     Referring to  FIGS. 2 and 5C , a sealant  350  may be formed, sealing a liquid crystal layer  300 . 
     A sealant  350  may be disposed on two opposite ends of the first substrate  100  and the second substrate  200 . 
     The liquid crystal lens may include a lens area LA and a non-lens area NLA. A sealant  350  may be disposed on the non-lens area NLA, sealing the liquid crystal layer  300 . 
     Referring to  5 D, a liquid crystal composition may be injected between the first substrate  100  and the second substrate  200 , forming the liquid crystal layer  300 . 
     The liquid crystal composition may include liquid crystal molecules  310  and mesogens  320 . The mesogens  320  may decrease a flow of the liquid crystal molecules. 
     When no voltages are applied to the electrodes EL 1 , EL 2 , and EL 3 , the major axis of the liquid crystal molecules  310  is aligned substantially parallel with the first the second substrates  100  and  200 . The liquid crystal molecules  310  may be pre-tilted. 
     For example, the liquid crystal molecules  310  may be aligned in the rubbing direction of the first alignment layer  120 . The liquid crystal molecules  310  may be aligned in the first direction D1. 
     The liquid crystal molecules  310  adjacent to the second substrate  200  may be aligned in the rubbing direction of the second alignment layer  210 . The liquid crystal molecules  310  may be pre-tilted clockwise from the first direction D1 by about 10° or less. For example, the liquid crystal molecules  310  adjacent to the second substrate  200  may have a pre-tilted angle, which is equal to or less than about 10°. 
     When the liquid crystal molecules  310  are positioned in the middle portion of the first substrate  100  and the second substrate  200 , the major axis of the liquid crystal molecules  310  may be aligned substantially parallel with an upper surface of the first substrate  100 . The major axis of the liquid crystal molecules  310  may be aligned in the first direction D1. 
     Referring to  FIGS. 5E and 5F , voltages may be applied to the electrodes EL 1 , EL 2 , and EL 3 , respectively, and light may be radiated to the liquid crystal layer  300  including the mesogens  320 . 
     The mesogens  320  may be photo-cured. The mesogens  320  may be injected in a monomer state into the first substrate  100  and the second substrate  200 . After the injection, voltages may be applied to the electrodes EL 1 , EL 2 , and EL 3 , respectively, and light may be radiated to the mesogens  320 . The light may be an ultraviolet (UV) ray. When the light is radiated to the mesogens  320 , the mesogen monomers of the mesogens  320  may react with each other. The light radiation may last during about 10 seconds to about 30 seconds. 
     Thus, the mesogens  320  may be rendered to be adjacent to the first substrate  100  and the second substrate  200 . The mesogens  320  may be formed between the liquid crystal molecules  310  adjacent to the first substrate  100  and the second substrate  200 . 
     Therefore, the mesogens  320  may be adjacent to the first substrate  100  and the second substrate  200 , and the mesogens  320  may prevent a flow of the liquid crystal molecules  310 . The mesogens  320  may prevent the liquid crystal molecules  310  from rotating to the rubbing directions of the first alignment layer  120  and the second alignment layer  210 . 
     The weight of the mesogens  320  may be in a range from about 0.1% by weight to about 1.0% by weight, with respect to the total weight of the liquid crystal composition. 
     The liquid crystal lens may be formed by a liquid crystal composition including mesogens  320 . Therefore, the anchoring energy and response speed of liquid crystal may be increased. 
     A liquid crystal lens and a liquid crystal display apparatus in accordance with exemplary embodiments of the present invention may be applicable to electronic devices, such as televisions, personnel computers, mobile devices, etc. 
     While the inventive concept has been shown and described with reference to exemplary embodiments thereof, it will be apparent to those of ordinary skill in the art that various changes in form and detail may be made thereto without departing from the spirit and scope of the inventive concept as defined by the following claims.