POLARIZING PLATE AND "LIQUID CRYSTAL DISPLAY COMPRISING THE SAME The present invention relates to a polarizing plate and a liquid crystal display device. ' Background Art A liquid crystal display (LCD) device is applied in various fields because it has low power consumption and can be formed in a thin plane. The LCD device includes a liquid crystal panel including a liquid crystal present between transparent substrates and polarizing plates attached to both surfaces of the liquid crystal panel. The polarizing plate generally has a structure shown in FIG. 1. That is, the polarizing plate 1 may include a polarizer 11, and protective films 12a and 12b attached to .both surfaces of the polarizer 11, Also, the polarizing plate 1 may include a pressure-sensitive adhesive layer 13 formed under the protective film 12b and may be used to attach to a liquid crystal panel, and may further include a releasing film 14 formed under the pressure-sensitive adhesive layer 13. Although not shown in FIG. 1, the polarizing plate may include an additional functional film such as a reflection preventing film. In such a structure of the conventional polarizing plate, to provide a device having a smaller thickness and light weight, for example, as described in patent reference No. 1, there have been attempts to form the polarizing plate while omitting one of the protective films 12a and 12b formed on both surfaces of the conventional polarizer 11. However, it is difficult to provide a polarizing plate with desired performance without using a protective film. The present invention relates to a polarizing plate including: a polarizer; and a pressure-sensitive adhesive layer attached to at least one surface of the polarizer that has a first surface and a second surface that have different peeling forces with respect to a non-alkali glass. Hereinafter, the polarizing plate of the present invention will be described in further detail. In one example, the pressure-sensitive adhesive layer may be a single- layer structure having first and second surfaces. Here,'the single layer structure means a structure in which the pressure-sensitive adhesive layer is a single-layered pressure-sensitive adhesive layer. Therefore, a pressure-sensitive adhesive layer having a structure in which at least two pressure-sensitive adhesive layers are stacked is excluded. In one example, a first surface of the pressure-sensitive adhesive layer may be attached to a polarizer, and a second'surface thereof may be a pressure-sensitive adhesive surface for attaching the polarizing plate to a liquid crystal panel. Here, the first surface may have a lower peeling force with respect to the non-alkali glass than the second surface. A kind of the polarizer included in the polarizing plate of the present invention is not particularly limited, and any common material known in the art, for example, a polyvinyl alcohol-based polarizer, may be employed without limitation. A polarizer is a functional film or sheet capable of extracting light vibrating in only one direction from incident light vibrating in various directions. In a structure of a conventional polarizing plate, protective films such as triacetyl cellulose (TAC) films are generally attached to both surfaces of the polarizer. In the polarizing plate of the present invention, at least one of the above-mentioned protective films is omitted. That is, at least one surface of the polarizer does not have a protective film attached thereto, and the first surface of the pressure-sensitive adhesive layer may be attached to a surface of the polarizer which does not have a protective film. Furthermore, the pressure-sensitive adhesive layer may serve to attach the polarizing plate to a liquid crystal display panel. FIG. 2 is a cross-sectional view of an exemplary polarizing plate 2 according to the present invention. As shown in FIG. 2, the polarizing plate 2 may include a polarizer 21; and a pressure-sensitive adhesive layer 22 formed on one surface of the polarizer 21. In FIG. 2, the protective film 23 is attached to a surface of the polarizer 21 which does not have the pressure-sensitive adhesive layer 22. However, the polarizing plate 2 of FIG. 2 is an example of the present invention, and for example, neither surface of the polarizer may have a protective film attached thereto in the present invention. Since the polarizer is formed of a hydrophilic resin such as polyvinyl alcohol, it is generally vulnerable to moisture. Furthermore, since the polarizer is formed via a stretching process, it is easily contracted in moist conditions, resulting in degradation in the optical characteristics of the polarizing plate. For this reason, in the structure of the conventional polarizing plate, to reinforce strength of the polarizer, as shown in FIG. 1, protective films exemplified as TAC films are generally formed on both surfaces of the polarizer. When a protective film is not used, the polarizer has low dimensional stability, and durability or an optical property of the polarizing plate is degraded. [0014] In the present invention, the above-mentioned problems can be resolved by forming a pressure-sensitive adhesive layer on the polarizer instead of a protective film. Here, the surfaces of the pressure-sensitive adhesive layer are designed to have different peeling forces with respect to a non-alkali glass. Due to the removal of the protective film, the present invention can provide a thinner and lighter polarizing plate, which may be referred to as a thin polarizing plate throughout the specification. In other words, the polarizer does not have a protective film on at least one surface thereof, and a first surface of the pressure-sensitive adhesive layer, that is, a surface that has a relatively low peeling force, may be attached to a surface of the polarizer which does not have a protective film. FIG. 3 illustrates a single-layered pressure-sensitive adhesive layer 10 having a first surface 10A arid a second surface 10B. When the first surface of the pressure-sensitive adhesive layer attached to the polarizer is designed to have a low peeling force with respect to a non-alkali glass, contraction or expansion of the polarizer under severe conditions including high temperature or high humidity may be inhibited. In addition, when the second surface 10B serving to attach the polarizing plate to a liquid crystal panel is designed to have a high peeling force, the polarizer may have excellent wettability to an adherent. In one example, the first surface may have a peel strength to a non-alkali glass of 5 to 100 gf/25 mm, preferably, 5 to 70 gff25 mm, more preferably, 10 to 70 g#25 mm, and most preferably, 10 to 50 g#25 mm. In addition, the second surface may have a peeling force to a non-alkali glass of 100 to 1,000 g&25 mm, preferably 150 to 800 gf/25 mm, more preferably 150 to 70 g£75 mm, and most preferably 250 to 750 g#25 mm. The peeling force will be measured by a method described in the following example. When the peeling force o f the first and second surfaces are controlled in the above-mentioned range, the contraction and" expansion of the polarizer under high-temperature or high-humidity conditions may be effectively inhibited, and the polarizer may have excellent wettability to the liquid crystal panel. The pressure-sensitive adhesive layer which is formed as a single layer structure and whose both surfaces have different peeling forces may be, for-example, formed by making a modulus gradient in the direction of the thickness of the pressure-sensitive adhesive layer.. Referring to FIG. 3, in one example, the pressure-sensitive adhesive layer 10 may have a tensile modulus gradient in a thickness direction from the first surface 10 A to the second surface 10B (represented by arrow T of FIG. 3). The change in tensile modulus in the thickness direction means a continuous or discontinuous increase or decrease in the tensile modulus of the pressure-sensitive adhesive layer in the thickness direction. In detail, the tensile modulus may be changed in the thickness direction to show the highest tensile modulus on the first surface 10A, and the lowest tensile modulus on the second surface 10B. To give such a change in the tensile modulus of the pressure-sensitive adhesive layer in the thickness direction, a method of controlling the degree of curing of the pressure-sensitive adhesive layer differently in the thickness direction may be used. For example, as described later, when the. pressure-sensitive adhesive layer is formed using a UV curable pressure-sensitive adhesive composition, a pressure-sensitive adhesive layer whose storage modulus is changed in the thickness direction may be formed by suitably controlling the thickness of the coated pressure-sensitive adhesive composition and the intensity of UV rays irradiated during the curing of the composition. In other words, when the pressure-sensitive adhesive layer is formed by such a method, the irradiated UY rays penetrate in a thickness direction of the pressure-sensitive adhesive composition, and then are dissipated or absorbed by reaction with an internal photo initiator. Here, as the dissipation or absorption of the UV rays is suitably adjusted, the intensity of the UV rays inducing the curing reaction is decreased downwards in the thickness direction of the pressure-sensitive adhesive composition, and therefore the degree of curing may be controlled differently in the thickness :direction. In the present invention, in some cases, a pressure-sensitive adhesive layer whose degree of curing is changed in the thickness direction may be formed by a method of blending a UV absorber in a suitable amount with the photocurable pressure-sensitive adhesive composition. In other words, the UV absorber blended with the pressure-sensitive adhesive composition may absorb UV rays applied to the composition during the curing process, and thus'a difference in the amount of UV radiation is made in the thickness direction, and thereby the degree of curing may be controlled differently. When the pressure-sensitive adhesive layer is controlled for the tensile modulus to be changed in the thickness direction, the pressure-sensitive adhesive may have an average tensile modulus at 25 °C of 0.1 to 500 MPa, preferably 10 to 400 MPa, more preferably, 1 to 300 MPa, and most preferably, 45 to 300 MPa. When the average of the tensile modulus is controlled in the above range, the polarizing plate may effectively inhibit light leakage, and have excellent durability in high-temperature or high-humidity conditions. Meanwhile, the tensile modulus will be measured by the method described in the following example. The thickness of the pressure-sensitive adhesive layer of the present invention is not particularly limited, but may be controlled in a range of 20 to 80 urn, and preferably 25 to 60 jim. When the pressure-sensitive adhesive layer has a thickness of less than 20 um, the efficiency in inhibiting contraction or expansion of the polarizer may be decreased, or the efficiency in the implementation of the pressure-sensitive adhesive layers to have different degrees of curing in the thickness direction according to the above-described curing process may be degraded. When the pressure-sensitive adhesive layer has a thickness of more than 80 u.m, it may be an obstacle to make the polarizing plate thin. In the present invention, a method of forming the pressure-sensitive adhesive layer is not particularly limited. For example, the pressure-sensitive adhesive layer may be formed by curing with a conventional room temperature curable, moisture curable, thermal curable or photocurable pressure-sensitive adhesive composition, preferably a UV curable pressure-sensitive adhesive composition. The curing of the pressure-sensitive adhesive composition means expressing a pressure-sensitive adhesive characteristic in the pressure-sensitive adhesive composition by a physical action or chemical reaction by irradiating light, maintaining the pressure-sensitive adhesive composition at a predetermined temperature or supplying a suitable level of humidity. In one example, the pressure-sensitive adhesive layer may include an interpenetrating polymer network (referred to as an "IPN"). The term "IPN" may indicate a state-in which at least two kinds of crosslinking structures are present in a pressure-sensitive adhesive layer, and in one example, the crosslinking structure may be present in an entanglement, linking or penetrating state. When the pressure-sensitive adhesive layer includes the IPN, a polarizing plate with excellent durability," workability, optical characteristics and light leakage prevention in severe conditions can be realized. [0025] When the pressure-sensitive adhesive layer has the IPN structure, the pressure-sensitive adhesive layer may include a crosslinking structure including an acryl polymer present in a crosslinked state and a crosslinking structure including a polymerized photopolymerizable compound. For example, the acryl polymer may have a weight average molecular weight (Mw) of 500000 or more. The weight average molecular weight is a converted figure for standard polystyrene measured by gel permeation chromatography (GPC). " Herein, unless specifically defined otherwise, the term "molecular weight" indicates a "weight average molecular weight," When the molecular weight of the polymer is designed at 500000 or more, it is possible to form a pressure-sensitive adhesive layer having excellent durability under a severe condition.The upper limit of the molecular weight is not particularly limited, and may be, for example, controlled in a range of 2500000 or less in consideration of the durability of the adhesive or coatability of the composition. In one example, the polymer may include a (meth)acrylic acid ester monomer and a crosslinkable monomer as polymerization units. [0028] As the (meth)acrylic acid ester monomer, alkyl (meth)acrylate may be used. In consideration of the control of cohesion, glass transition temperature and adhesion, alkyl (meth)acrylate including an alkyl group having 1 to 14 carbon atoms may be used. Examples of such monomers may include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, sec-butyl (meth)acrylate, pentyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-ethyIbutyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, lauryl (meth)acrylate and tetradecyl (meth)acrylate, which may be used alone or in combination of at least two thereof. As a crosslinkable monomer, any one. including both a co-polymerizable functional group and a crosslinkable functional group in the molecule and capable of being copolymerized with the (meth)acrylic acid ester monomer and the monomer of Formula 1, and providing the crosslinkable functional group to the polymer after co-polymerization may be used without limitation. Examples of the crosslinkable functional groups may. include a hydroxyl group, a carboxyl group, a nitrogen-containing group such as an amino group, an isocyanate group and an epoxy group. In the art, various crosslinkable monomers capable of providing the above-mentioned crosslinkable functional group are known, and the monomers may all be used in the present invention. Examples of the crosslinkable monomers may include, but are not limited to, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 2-hydroxyethyleneglycol (meth)acrylate, 2-hydroxypropyl eneglycol (meth)acrylate, (meth)acrylic acid, 2-(meth)acryloyloxy acetic acid, 3-(meth)acryloyloxy propionic acid, 4-(meth)acryloyloxy butyric acid, an acrylic acid dimer, itaconic acid, maleic acid and maleic acid anhydride, (meth)acrylamideJ N-vinyl pyrrolidone or N-vinyl caprolactame. One or at least two of such crosslinkable monomers may be included in the polymer. The acryl polymer may include 80 to 99.8 parts by weight of (meth)acrylic acid ester monomer and 0.01 to 3 parts by weight of a crosslinkable monomer. Herein, unless specifically defined otherwise, the term "part(s) by weight" refers to a-weight ratio. When the weight ratio of the monomers of the acryl polymer is controlled as described above, a pressure-sensitive adhesive having excellent durability or optical properties may be provided. The acryl polymer may further include a suitable co-monomer other than those described above. For example, the polymer may Anther include a polymer of Formula 1 as a polymerization unit. In Formula 1, R is hydrogen or an alkyl- group, A is an alkylene group, Ri is an alkyl or aryl group, and n is any one of 1 to 50. The monomer of Formula ! provides an alkyleneoxide group to the polymer. In one example, the alkyleneoxide group may be a linear, branched or cyclic alkyleneoxide group having 1 to 20, 1 to 16, .1 to 12, 1 to 8 or 1 to 4 carbon atoms. The alkyleneoxide group may allow the pressure-sensitive adhesive layer to exhibit a low haze and effectively inhibit light leakage when applied to the polarizing plate. The alkyleneoxide group may serve to maintain a peeling force at a proper level while the modulus of the pressure-sensitive In Formula 1, R may be a hydrogen or an alkyl group having 1 to 4 carbon atoms, and be preferably hydrogen or a methyl group. In Formula 1, A may be a substituted or unsiibstituted alkylene group having 1 to 20, 1 tol6, 1 to 12, 1 to 8, or 1 to 4 carbon atoms, and the alkylene group may have a linear, branched or cyclic structure. In Formula 1, when R] is an alkyl group, the alkyl group may also be a substituted or unsubstituted alkyl having 1 to 20, 1 to 16, 1 to 12, 1 to 8 or 1 to 4 carbon atoms, and the alky group may have a linear, branched or cyclic group. In Formula 1, when Ri is an aryl group, the aryl group miay also have 6 to 20, 6 to 16, or 6 to 12 carbon atoms. In Formula 1, n is preferably one of 1 to 25, more preferably, 1 to 15, and most preferably, 1 to 6. Specific examples of the monomers of Formula 1, may include alkoxy alkyleneglycol (meth)acrylic acid ester, alkoxy dialkyleneglycol (meth)ac rylic acid ester, alkoxy trialkyleneglycol (meth)acrylic acid ester, alkoxy tetraalkyleneglycol (meth)acrylic acid ester, alkoxy polyethyleneglycol (meth)acrylic acid ester, phenoxy alkyleneglycol (meth)acrylic acid ester, phenoxy dialkyleneglycol (meth)acrylic acid ester, phenoxy trialkyleneglycol (meth)a crylic acid ester, phenoxy tetraalkyleneglycol (meth) acrylic acid ester or phenoxy polyalkyleneglycol (meth)acrylic acid ester, and one or at least two of the monomers may be included in the polymer. When the acryl polymer includes a monomer of Formula 2, the acryl polymer may include 40 to 99.9 parts by weight of a (meth)acrylic acid ester monomer, 10 to 50 parts •by weight of a monomer of Formula 1, and 0.01 to 30 parts by weight of a crosslinkable monomer. Herein, unless specifically described otherwise, the term (' Illuminance: 250 mW/cm2 Amount of Light: 300 mJ/cm2 Formation of Polarizing Plate A polarizer was formed by stretching a polyvinyl alcohol-based resin film, staining the .film with iodine, and treating the resulting film with a boric acid aqueous solution. Subsequently, a 60' um-thick triacetyl cellulose (TAC) film was attached to one surface of the polarizer using a water-based polyvinyl alcohol-based adhesive. Afterwards, the first surface of the pressure-sensitive adhesive layer was laminated to a surface of the polyvinyl alcohol-based polarizer to which a TAC film was not attached using the same water-based polyvinyl alcohol-based adhesive as used above, thereby forming a polarizing plate. Examples 2 to 4 and Comparative Examples 1 to 4 Except that components of the pressure-sensitive adhesive compositions were changed as shown in Table I, a polarizing plate was formed by the same method as described in Example I. Herein, the tensile modulus of the pressure-sensitive adhesive layer was measured by a tensile stress-strain test according to a method defined in ASTM D638, or when it was difficult to directly measure the tensile modulus, a storage modulus was measured by the following method and then converted by the following formula. Specifically, a stacked structure formed in the structure shown in FIG. 4 (including a PET releasing film, a pressure-sensitive adhesive layer and a PET releasing film) was cut into a dog bone-type specimen in a.size of 7 cm (length)* 1 cm (width). Both ends of the specimen were fixed with tensile test jigs, and a tensile modulus was measured. The conditions for measuring the tensile modulus were as follows.