Light guide device and lighting device including same

Abstract

According to exemplary embodiments, a light guide device is provided. The light guide device comprises: a transparent layer; and an in-coupling element disposed on the transparent layer and including a patterned layer, wherein the patterned layer includes a plurality of patterns, and the plurality of patterns are configured to direct illumination light introduced into the transparent layer at the same angle.

Description

Light guide device and lighting device including the same

[0001] The present invention relates to a light guide device and a lighting device including the same.

[0002] The present disclosure claims the benefit of priority based on Korean Patent Application No. 10-2025-0026750 filed February 28, 2025, and all contents of Korean Patent Application No. 10-2025-0026750 are incorporated by reference into the present disclosure.

[0003] LED (Light Emitting Diode) chips and LED packages containing LED chips are increasingly expanding their applications as light sources due to their various advantages, such as low power consumption, high brightness, and long lifespan. A representative example of using LED chips and LED packages as lighting sources is a lighting device that includes a light guide plate.

[0004] Lighting devices including light guide plates and LED packages can achieve uniform surface lighting with a thin thickness, allowing for high space utilization and sophisticated designs in signage, panel lights, and displays.

[0005] The problem that the technical concept of the present invention aims to solve is to provide a light guide device capable of providing an enhanced user experience and a lighting device including the same.

[0006] According to exemplary embodiments of the present invention for solving the above-described problem, a light guide device is provided. The light guide device comprises a transparent layer; and an incoupling element comprising a patterned layer on the transparent layer; wherein the patterned layer comprises a plurality of patterns, and the plurality of patterns are configured to direct illumination light introduced into the transparent layer at the same angle.

[0007] The above plurality of patterns are spaced apart in a first direction parallel to the main surface of the transparent layer.

[0008] The spacing between the above plurality of patterns is in the range of 10 μm to 1000 μm.

[0009] The above plurality of patterns extend in a second direction perpendicular to the first direction.

[0010] The depth of each of the above plurality of patterns is in the range of 10μ to 500μm.

[0011] Each of the above plurality of patterns includes an inclined surface configured to direct the illumination light.

[0012] The angle of inclination of each of the above-mentioned multiple patterns is different from each other.

[0013] The spacing between the above plurality of patterns depends on the distance between the light source generating the illumination light and the transparent layer.

[0014] The spacing between the above plurality of patterns depends on the thickness of the transparent layer.

[0015] The spacing between the above plurality of patterns depends on the thickness of the patterned layer.

[0016] The above-described in-coupling element further includes an adhesive layer between the transparent layer and the patterned layer.

[0017] The spacing between the above plurality of patterns depends on the thickness of the adhesive layer.

[0018] The distance l_m between the first pattern among the plurality of patterns, in which the angle of incidence of the illumination light is 0°, and the second pattern arranged at the m-th position from the first pattern, satisfies the following equation, and

[0019] l_m=d0tan(Φ0_m)+d1tan(Φ1_m)+d2tan(Φ2_m)+ tan(Φ0_m)

[0020] Here, d0 is the distance between the light source configured to irradiate the illumination light and the light guide device, d1 is the thickness of the transparent layer, d2 is the thickness of the adhesive layer, and d3 is the thickness of the patterned layer, α is the directional angle of the illumination light directed by a plurality of patterns, Φ0_m is the directional angle of the illumination light between the light source and the light guide device, Φ1_m is the directional angle of the illumination light within the transparent layer, Φ2_m is the directional angle of the illumination light within the adhesive layer, and Φ3_m is the directional angle of the illumination light within the patterned layer.

[0021] The distance l_m between the first pattern among the plurality of patterns in which the angle of incidence of the illumination light is 0° and the second pattern arranged m-th from the first pattern, and the distance l_m-1 between the first pattern and the third pattern arranged m-1-th from the first pattern satisfy the following equation, and

[0022] l_m=d2tan(α)+l_m-1+ tan(β_m-1)+ tan(β_m)

[0023] Here, d2 is the thickness of the adhesive layer, α is the directional angle of the illumination light reflected by the plurality of patterns, β_m is the angle of inclination of the inclined surface of the second pattern, and β_m-1 is the angle of inclination of the inclined surface of the third pattern.

[0024] Among the plurality of patterns above, the inclination angle β_m of the inclined surface of the second pattern arranged m-th from the first pattern, from the first pattern where the incident angle of the illumination light is 0°, satisfies the following equation, and

[0025] (β_m)=90°-(Φ3_m-α) / 2

[0026] Here, α is the directional angle of the illumination light directed by the plurality of patterns, and Φ3_m is the directional angle of the illumination light within the patterned layer.

[0027] It further includes a reflective layer on the patterned layer above.

[0028] The directional angle of the illumination light reflected at each of the interfaces of the reflection layer and the plurality of patterns is the same.

[0029] The refractive index of the patterned layer is in the range of 1.5 to 2.

[0030] According to exemplary embodiments, a light guide device is provided, the light guide device comprises: a transparent layer; and an incoupling element comprising a patterned layer on the transparent layer; wherein the patterned layer comprises a plurality of patterns including inclined surfaces, the spacing between the plurality of patterns is different from one another, and the angle of inclination of the inclined surfaces of each of the plurality of patterns is different from one another.

[0031] According to exemplary embodiments of the present invention, illumination light can be steered using a film-type incoupling element so that the illumination light proceeds through total internal reflection at the same angle within a transparent layer. Accordingly, the reliability and uniformity of an illumination device including a light guide device can be improved.

[0032] The effects obtainable from the exemplary embodiments of the present invention are not limited to those mentioned above, and other unmentioned effects can be clearly derived and understood by those skilled in the art to which the exemplary embodiments of the present disclosure belong from the following description. That is, unintended effects resulting from the implementation of the exemplary embodiments of the present disclosure can also be derived by those skilled in the art from the exemplary embodiments of the present disclosure.

[0033] FIG. 1 is a plan view showing a lighting device according to exemplary embodiments.

[0034] Figure 2 is a cross-sectional view taken along the cutting line 1A-1A' of Figure 1.

[0035] Figure 3 is a graph showing the coupling efficiency according to the refractive index of the pattern layer.

[0036] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings. Instead, based on the principle that the inventor can appropriately define the concepts of terms to best describe his invention, they should be interpreted in a meaning and concept consistent with the technical spirit of the present invention.

[0037] Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention; thus, it should be understood that various equivalents and modifications that can replace them may exist at the time of filing this application.

[0038] In addition, in describing the present invention, if it is determined that a detailed description of related known components or functions may obscure the essence of the invention, such detailed description is omitted.

[0039] Since embodiments of the present invention are provided to more fully explain the invention to those skilled in the art, the shapes and sizes of the components in the drawings may be exaggerated, omitted, or schematically depicted for clearer explanation. Accordingly, the size or proportion of each component does not entirely reflect the actual size or proportion.

[0040]

[0041] FIG. 1 is a plan view showing a lighting device according to exemplary embodiments.

[0042] Figure 2 is a cross-sectional view taken along the cutting line 1A-1A' of Figure 1.

[0043] Referring to FIGS. 1 and FIGS. 2, the lighting device (100) may include a light source (110) and a light guide device (120).

[0044] A light source (110) can generate light (IL) based on external power. The light (IL) generated by a plurality of light sources (110) may have a wavelength in the visible light band. The light source (110) may include an LED chip.

[0045] The LED chip may include a first conductivity semiconductor layer, an active layer, and a second conductivity semiconductor layer. According to exemplary embodiments, the first conductivity semiconductor layer is Al x In y Ga 1-x-y It may be composed of a single-crystal nitride having a composition of N (0≤x≤1, 0≤y≤1, 0≤x+y≤1). The first conductivity semiconductor layer may be composed of a semiconductor doped with n-type impurities. According to exemplary embodiments, the first conductivity semiconductor layer may include GaN doped with Si, etc.

[0046] The active layer may be disposed on the first conductivity semiconductor layer. The active layer may emit light having a predetermined energy through the recombination of electrons and holes. According to exemplary embodiments, the active layer may include a multiple quantum well (MQW) structure in which quantum well layers (not shown) and quantum barrier layers (not shown) are alternately stacked. The thickness of each quantum well layer and quantum barrier layer may be in the range of about 3 nm to about 10 nm. According to exemplary embodiments, the multiple quantum well structure may include a multiple stacked structure of InGaN and GaN. However, it is not limited thereto, and according to exemplary embodiments, the active layer may be composed of a single quantum well (SQW) structure.

[0047] The second conductivity type semiconductor material layer is Al doped with p-type impurities. x In y Ga1-x-y It may be composed of a single-crystal nitride having a composition of N (0≤x≤1, 0≤y≤1, 0≤x+y≤1). The p-type impurity may include, for example, Mg, but is not limited thereto.

[0048] Here, two directions substantially parallel to the main surface (121S) of the transparent layer (121) of the light guide device (120) are defined as the X direction and the Y direction, and a direction substantially perpendicular to the main surface (121S) is defined as the Z direction. The X direction, the Y direction, and the Z direction may be substantially perpendicular to each other.

[0049] The light source (110) may overlap with the light guide device (120) in the Z direction. The light source (110) may overlap with the in coupling element (120I) of the light guide device (120) in the Z direction. The light source (110) may face the main surface (121S) of the light guide device (120). The light source (110) may face the in coupling element (120I) of the light guide device (120). The in coupling element (120I) may be adjacent to the first edge (120E1) of the light guide device (120). The first edge (120E1) may be substantially parallel to the Y direction.

[0050] The distance between the coupling element (120I) and the second edge (120E2) may differ from the distance between the coupling element (120I) and the first edge (120E1). The distance between the coupling element (120I) and the second edge (120E2) may be greater than the distance between the coupling element (120I) and the first edge (120E1). The second edge (120E2) may be substantially parallel to the Y direction. The second edge (120E2) may be opposite to the first edge (120E1). The second edge (120E2) may be spaced apart from the first edge (120E1) in the X direction.

[0051] The light source (110) may be configured to irradiate illumination light (IL) toward the main surface (121S) of the light guide device (120). The illumination light (IL) generated by the light source (110) may be incident on the light guide device (120). The light source (110) may be configured to irradiate illumination light (IL) toward the coupling element (120I) of the light guide device (120).

[0052] A light guide device (120) may be configured to guide and emit illumination light (IL) generated by a light source (110). The light guide device (120) may include a transparent layer (121) and an in coupling element (120I). The in coupling element (120I) may be a film-type optical element. According to exemplary embodiments, the light guide device (120) may include a film-type coupling element (120I) without an in coupling optical element of complex structure, thereby providing a compact light guide device (120).

[0053] Illuminating light (IL) generated by the light source (110) can be coupled to the light guide device (120) by the coupling element (120I). Illuminating light (IL) incident on the coupling element (120I) can undergo total internal reflection within the light guide device (120). Illuminating light (IL) incident on the coupling element (120I) can travel in the X direction. Illuminating light (IL) incident on the coupling element (120I) can move toward the second edge (120E2). Illuminating light (IL) incident on the coupling element (120I) can diffuse in the Y direction.

[0054] Illuminating light (IL) traveling within the light guide device (120) may be emitted to the outside of the light guide device (120) from the outcoupling portion of the light guide device (120). The emission mechanism of the illuminating light (IL) from the outcoupling portion may be scattering, but is not limited thereto. The outcoupling portion may include features for scattering the illuminating light (IL).

[0055] The transparent layer (121) may include a portion having a flat shape. The transparent layer (121) may further include a portion having a curved shape. The transparent layer (121) may include, for example, transparent glass.

[0056] The coupling element (120I) may include an adhesive layer (123), a patterned layer (125), and a reflective layer (127). The coupling element (120I) may be on a transparent layer (121). The coupling element (120I) may be attached to the transparent layer (121).

[0057] Each adhesive layer (123) may have high transparency with respect to the visible light band. The adhesive layer (123) may include PVB (polyvinyl butaalcohol), but is not limited thereto. The adhesive layer (123) may have adhesive properties. The patterned layer (125) formed by the adhesive layer (123) may be attached to the transparent layer (121). The adhesive layer (123) may be located between the patterned layer (125) and the transparent layer (121).

[0058] The patterned layer (125) may include a plurality of patterns (125P_0, 125P_1, 125P_2, …, 125P_N, 125P_-1, 125P_-2, …, 125P_-M). The plurality of patterns (125P_0, 125P_1, 125P_2, …, 125P_N, 125P_-1, 125P_-2, …, 125P_-M) may be formed, for example, by imprinting. Here, M and N are integers. M and N may be the same or different from each other.

[0059] The refractive index of the patterned layer (125) may be in the range of about 1.5 to about 2.0. The spacing between the plurality of patterns (125P_0, 125P_1, 125P_2, …, 125P_N, 125P_-1, 125P_-2, …, 125P_-M) may be in the range of about 10 μm to about 1000 μm. The depth of each of the plurality of patterns (125P_0, 125P_1, 125P_2, …, 125P_N, 125P_-1, 125P_-2, …, 125P_-M) may be in the range of about 10 μm to about 500 μm.

[0060] Each of the multiple patterns (125P_0, 125P_1, 125P_2, …, 125P_N, 125P_-1, 125P_-2, …, 125P_-M) can be extended in the Y direction. Each of the multiple patterns (125P_0, 125P_1, 125P_2, …, 125P_N, 125P_-1, 125P_-2, …, 125P_-M) can have a line shape. Each of the multiple patterns (125P_0, 125P_1, 125P_2, …, 125P_N, 125P_-1, 125P_-2, …, 125P_-M) can have a sawtooth shape.

[0061] Multiple patterns (125P_0, 125P_1, 125P_2, …, 125P_N, 125P_-1, 125P_-2, …, 125P_-M) can be arranged in the X direction. Multiple patterns (125P_0, 125P_1, 125P_2, …, 125P_N, 125P_-1, 125P_-2, …, 125P_-M) can be spaced apart in the X direction.

[0062] Pattern (125P_0) may be at a reference position of multiple patterns (125P_0, 125P_1, 125P_2, …, 125P_N, 125P_-1, 125P_-2, …, 125P_-M). Pattern (125P_0) may also be referred to as a reference pattern. Pattern (125P_0) may be superimposed with the light source (110) in the Z direction. The angle of incidence of the illumination light (IL) on pattern (125P_0) may be approximately 0°, but is not limited thereto.

[0063] Patterns (125P_1, 125P_2, …, 125P_N) can be arranged in numbered order. Among the patterns (125P_1, 125P_2, …, 125P_N), the subsequent one may be further from pattern (125P_0) than the preceding one among the patterns (125P_1, 125P_2, …, 125P_N). For example, the distance between pattern (125P_2) and pattern (125P_0) may be greater than the distance between pattern (125P_1) and pattern (125P_0).

[0064] Patterns (125P_-1, 125P_-2, …, 125P_-M) can be arranged in numbered order. Among the patterns (125P_-1, 125P_-2, …, 125P_-M), the subsequent one may be further from pattern (125P_0) than the preceding one among the patterns (125P_-1, 125P_-2, …, 125P_-M). For example, the distance between pattern (125P_-2) and pattern (125P_0) may be greater than the distance between pattern (125P_-1) and pattern (125P_0).

[0065] Each of the plurality of patterns (125P_0, 125P_1, 125P_2, …, 125P_N, 125P_-1, 125P_-2, …, 125P_-M) may include an inclined surface (125I). Each of the plurality of patterns (125P_0, 125P_1, 125P_2, …, 125P_N, 125P_-1, 125P_-2, …, 125P_-M) may be configured to direct illumination light (IL). The illumination light (IL) can be directed in a direction set by the inclined surface (125I) of each of the multiple patterns (125P_0, 125P_1, 125P_2, …, 125P_N, 125P_-1, 125P_-2, …, 125P_-M).

[0066] Each inclined surface (125I) of a plurality of patterns (125P_0, 125P_1, 125P_2, …, 125P_N, 125P_-1, 125P_-2, …, 125P_-M) may have an angle of inclination (β_0, β_1, β_2, …, β_N, β_-1, β_-2, …, β_-M) set with respect to the normal direction (i.e., Z direction). The angle of the inclined surface (125I) of pattern (125P_0) with respect to the normal direction (i.e., Z direction) may be the angle of inclination (β_0). Likewise, the angle of the inclined surface (125I) of pattern (125P_1) with respect to the normal direction (i.e., Z direction) may be the angle of inclination (β_1).

[0067] In the following, the inclination angle (β_0, β_1, β_2, …, β_N, β_-1, β_-2, …, β_-M) of each of the multiple patterns (125P_0, 125P_1, 125P_2, …, 125P_-M) is an angle with respect to the normal direction (i.e., Z direction).

[0068] Each of the inclination angles (β_0, β_1, β_2, …, β_N, β_-1, β_-2, …, β_-M) may be in the range of about 30° to about 80°. The inclination angle (β_0) of the pattern (125P_0) may be in the range of about 45° to about 80°.

[0069] At this time, the slope angle β_m of the pattern (hereinafter, the m-th pattern) placed m-th from pattern (125P_0) among the plurality of patterns (125P_0, 125P_1, 125P_2, …, 125P_N, 125P_-1, 125P_-2, …, 125P_-M) satisfies the following equation.

[0070] [Equation 1]

[0071] (β_m)=90°-(Φ3_m-α) / 2

[0072] Here, m is an integer greater than or equal to -M and less than or equal to N. Also, Φ3_m is the directional angle within the patterned layer (125) of the illumination light (IL) reaching the m-th pattern among the plurality of patterns (125P_0, 125P_1, 125P_2, …, 125P_N, 125P_-1, 125P_-2, …, 125P_-M). In the following, unless otherwise noted, the directional angle of the illumination light (IL) is an angle with respect to the normal direction (i.e., Z direction).

[0073] The directional angle of the illumination light (IL) reaching the patterns (125P_1, 125P_2, 125P_N) within the patterned layer (125) can have a positive value. The directional angle of the illumination light (IL) reaching the patterns (125P_-1, 125P_-2, 125P_-N) within the patterned layer (125) can have a negative value.

[0074] According to exemplary embodiments, the angle of inclination of each of the plurality of patterns (125P_0, 125P_1, 125P_2, …, 125P_N, 125P_-1, 125P_-2, …, 125P_-M) may be different from one another. For example, the angle of inclination (β_2) of the slope (125I) of pattern (125P_2) may be different from the angle of inclination (β_1) of the slope (125I) of pattern (125P_1). For example, the angle of inclination (β_-2) of the slope (125I) of pattern (125P_-2) may be different from the angle of inclination (β_-1) of the slope (125I) of pattern (125P_-1).

[0075] The angle of inclination of each slope surface (125I) of the patterns (125P_1, 125P_2, …, 125P_N) can increase as it moves further away from the pattern (125P_0). For example, the angle of inclination (β_2) of the slope surface (125I) of the pattern (125P_2) can be greater than the angle of inclination (β_1) of the slope surface (125I) of the pattern (125P_1).

[0076] The angle of inclination of each slope surface (125I) of the patterns (125P_-1, 125P_-2, …, 125P_-M) can be smaller as it is further from the pattern (125P_0). For example, the angle of inclination (β_-2) of the slope surface (125I) of the pattern (125P_-2) can be smaller than the angle of inclination (β_-1) of the slope surface (125I) of the pattern (125P_-1).

[0077] In addition, the directional angle (α) is the angle in the normal direction with respect to the illumination light (IL) reflected by multiple patterns (125P_0, 125P_1, 125P_2, …, 125P_N, 125P_-1, 125P_-2, …, 125P_-M). According to exemplary embodiments, a plurality of patterns (125P_0, 125P_1, 125P_2, …, 125P_N, 125P_-1, 125P_-2, …, 125P_-M) can direct the illumination light (IL) in the same direction, and accordingly, the directional angle (α) of the illumination light (IL) reflected by each of the plurality of patterns (125P_0, 125P_1, 125P_2, …, 125P_N, 125P_-1, 125P_-2, …, 125P_-M) can have a constant value. Additionally, the directional angle (α) may be greater than or equal to the critical angle of the transparent layer (121).

[0078] In Equation 1, Φ3_m can be calculated using Snell's Law as in Equation 2.

[0079] [Equation 2]

[0080] n3·sin(Φ3_m)=n2·sin(Φ2_m)=n1·sin(Φ1_m)=n0·sin(Φ0_m)

[0081] Here, n0 is the refractive index of the space between the light source (110) and the light guide device (120), n1 is the refractive index of the transparent layer (121), n2 is the refractive index of the adhesive layer (123), and n3 is the refractive index of the patterned layer (125).

[0082] The illumination light (IL) traveling at a directional angle (Φ3_m) in the patterned layer (125) travels at a directional angle (Φ2_m) in the adhesive layer (123), travels at a directional angle (Φ1_m) in the transparent layer (121), and can travel at a directional angle (Φ1_m) in the space between the light source (110) and the light guide device (120). In particular, when m=0 (i.e., in the case of a reference pattern), Φ3_m, Φ2_m, Φ1_m, and Φ0_m are all 0.

[0083] The distance l_m between the m-th pattern and the pattern (125P_0) and the distance l_m-1 between the m-1-th pattern satisfy the following Equation 3.

[0084] [Equation 3]

[0085] l_m=d0tan(Φ0_m)+d1tan(Φ1_m)+d2tan(Φ2_m)+ tan(Φ0_m)

[0086] =d2tan(α)+l_m-1+ tan(β_m-1)+ tan(β_m)

[0087] Here, d0 is the distance between the light source (110) and the light guide device (120) (e.g., distance in the Z direction), d1 is the thickness of the transparent layer (121) (e.g., thickness in the Z direction), d2 is the thickness of the adhesive layer (123) (e.g., thickness in the Z direction), and d3 is the thickness of the patterned layer (125) (e.g., thickness in the Z direction).

[0088] According to exemplary embodiments, the distance (e.g., distance in the X direction) between the m-th pattern among a plurality of patterns (125P_1, 125P_2, …, 125P_N, 125P_-1, 125P_-2, …, 125P_-M) and the pattern (125P_0) may depend on the distance (d0) between the light source (110) and the transparent layer (121).

[0089] According to exemplary embodiments, the spacing between a plurality of patterns (125P_1, 125P_2, …, 125P_N, 125P_-1, 125P_-2, …, 125P_-M) (e.g., spacing in the X direction) may depend on the distance (d0) between the light source (110) and the transparent layer (121).

[0090] According to exemplary embodiments, the distance (e.g., distance in the X direction) between the m-th pattern and the pattern (125P_0) among a plurality of patterns (125P_1, 125P_2, …, 125P_N, 125P_-1, 125P_-2, …, 125P_-M) may depend on the thickness (d1) of the transparent layer (121).

[0091] According to exemplary embodiments, the spacing between a plurality of patterns (125P_1, 125P_2, …, 125P_N, 125P_-1, 125P_-2, …, 125P_-M) (e.g., spacing in the X direction) may depend on the thickness (d1) of the transparent layer (121).

[0092] According to exemplary embodiments, the distance (e.g., distance in the X direction) between the m-th pattern and the pattern (125P_0) among a plurality of patterns (125P_1, 125P_2, …, 125P_N, 125P_-1, 125P_-2, …, 125P_-M) may depend on the thickness (d2) of the adhesive layer (123).

[0093] According to exemplary embodiments, the spacing between a plurality of patterns (125P_1, 125P_2, …, 125P_N, 125P_-1, 125P_-2, …, 125P_-M) (e.g., spacing in the X direction) may depend on the thickness (d2) of the adhesive layer (123).

[0094] According to exemplary embodiments, the distance (e.g., distance in the X direction) between the m-th pattern and the pattern (125P_0) among a plurality of patterns (125P_1, 125P_2, …, 125P_N, 125P_-1, 125P_-2, …, 125P_-M) may depend on the thickness (d3) of the patterned layer (125).

[0095] According to exemplary embodiments, the spacing between a plurality of patterns (125P_1, 125P_2, …, 125P_N, 125P_-1, 125P_-2, …, 125P_-M) (e.g., spacing in the X direction) may depend on the thickness (d3) of the patterned layer (125).

[0096] From Equation 3, multiple patterns (125P_1, 125P_2, …, 125P_N, 125P_-1, 125P_-2, …, 125P_-M) _m can be calculated by Equation 4 below.

[0097] [Equation 4]

[0098] Δ_m=l_m-l_m-1=d2tan(α)+ tan(β_m-1)+ tan(β_m)

[0099] According to exemplary embodiments, the spacing between a plurality of patterns (125P_1, 125P_2, …, 125P_N, 125P_-1, 125P_-2, …, 125P_-M) may differ from one another. For example, the spacing between patterns (125P_0, 125P_1) may differ from the spacing between patterns (125P_1, 125P_2). For example, the spacing between patterns (125P_0, 125P_-1) may differ from the spacing between patterns (125P_-1, 125P_-2).

[0100] The spacing between patterns (125P_0, 125P_1, 125P_2, …, 125P_N) can be larger as they are further from pattern (125P_0). For example, the spacing between patterns (125P_1, 125P_2) can be larger than the spacing between patterns (125P_0, 125P_1).

[0101] The spacing between patterns (125P_0, 125P_-1, 125P_-2, …, 125P_-M) can be smaller as they are further from pattern (125P_0). For example, the spacing between patterns (125P_-1, 125P_-2) can be smaller than the spacing between patterns (125P_0, 125P_-1).

[0102] A reflective layer (127) may be on a patterned layer (125). The reflective layer (127) may have a high reflectivity for the wavelength band of the illumination light (IL). The illumination light (IL) may be reflected at the interface between the reflective layer (127) and the patterned layer (125). The interface between the reflective layer (127) and the patterned layer (125) may be oriented toward the second edge (120E2) so that the illumination light (IL) reflected at the interface between the reflective layer (127) and the patterned layer (125) is directed toward the second edge (120E2).

[0103] According to exemplary embodiments, the illumination light (IL) reflected at the interface between the reflective layer (127) and the patterned layer (125) can travel with the same directional angle (α) regardless of position, and accordingly, the reliability and uniformity of the illumination device (100) can be improved.

[0104]

[0105] FIG. 3 is a graph showing the coupling efficiency according to the refractive index. In the graph of FIG. 3, the refractive index of the transparent layer (121) is about 1.5, and the directional angle (α) is about 75°.

[0106] Referring to FIGS. 1 to 3, when the number of multiple patterns (125P_1, 125P_2, …, 125P_N, 125P_-1, 125P_-2, …, 125P_-M) within the area covered by illumination light (IL) emitted by the light source (110) increases, the proportion of the portion of illumination light (IL) guided by the light guide device (120) can be increased, and accordingly, the incoupling efficiency of the light guide device (120) can be improved.

[0107] When the refractive index of the patterned layer (125) increases, the distance lm calculated according to Equation 3 can be reduced, and the density (e.g., area density) of the plurality of patterns (125P_1, 125P_2, …, 125P_N, 125P_-1, 125P_-2, …, 125P_-M) increases, so the coupling efficiency of the light guide device (120) can be improved.

[0108] The coupling efficiency η of the light guide device (120) can be calculated by Equation 5.

[0109] [Equation 5]

[0110]

[0111] The present invention has been described in more detail above through drawings and embodiments. However, the configurations described in the drawings or embodiments described in this specification are merely one embodiment of the present invention and do not represent all technical concepts of the present invention; therefore, it should be understood that various equivalents and modifications that can replace them may exist at the time of filing this application.

Claims

1. Transparent layer; and It includes an coupling element comprising a patterned layer on the above transparent layer; The above-mentioned patterned layer includes a plurality of patterns, and A light guide device characterized by the above plurality of patterns being configured to direct the illumination light introduced into the transparent layer at the same angle.

2. In Paragraph 1, A light guide device characterized in that the plurality of patterns are spaced apart in a first direction parallel to the main surface of the transparent layer.

3. In Paragraph 1, A light guide device characterized in that the spacing between the plurality of patterns is in the range of 10 μm to 1000 μm.

4. In Paragraph 2, A light guide device characterized in that the above plurality of patterns extend in a second direction perpendicular to the first direction.

5. In Paragraph 1, A light guide device characterized in that the depth of each of the above plurality of patterns is in the range of 10μ to 500μm.

6. In Paragraph 1, A light guide device characterized in that each of the above plurality of patterns includes an inclined surface configured to direct the illumination light.

7. In Paragraph 6, A light guide device characterized in that the angle of inclination of each of the above-mentioned plurality of patterns is different from each other.

8. In Paragraph 1, A light guide device characterized in that the spacing between the plurality of patterns above depends on the distance between the light source generating the illumination light and the transparent layer.

9. In Paragraph 1, A light guide device characterized in that the spacing between the plurality of patterns depends on the thickness of the transparent layer.

10. In Paragraph 1, A light guide device characterized in that the spacing between the plurality of patterns depends on the thickness of the patterned layer.

11. In Paragraph 1, A light guide device characterized in that the above-described in-coupling element further includes an adhesive layer between the transparent layer and the patterned layer.

12. In Paragraph 11, A light guide device characterized in that the spacing between the plurality of patterns depends on the thickness of the adhesive layer.

13. In Paragraph 11, The distance l_m between the first pattern, in which the angle of incidence of the illumination light is 0°, and the second pattern arranged at the m-th position from the first pattern among the plurality of patterns above satisfies the following equation, and l_m=d0tan(Φ0_m)+d1tan(Φ1_m)+d2tan(Φ2_m)+ tan(Φ0_m) Here, d0 is the distance between a light source configured to irradiate the illumination light and the light guide device, d1 is the thickness of the transparent layer, d2 is the thickness of the adhesive layer, and d3 is the thickness of the patterned layer, α is the directional angle of the illumination light directed by a plurality of patterns, Φ0_m is the directional angle of the illumination light between the light source and the light guide device, Φ1_m is the directional angle of the illumination light within the transparent layer, Φ2_m is the directional angle of the illumination light within the adhesive layer, and Φ3_m is the directional angle of the illumination light within the patterned layer, characterized by a light guide device.

14. In Paragraph 11, The distance l_m between the first pattern among the plurality of patterns in which the angle of incidence of the illumination light is 0° and the second pattern arranged m-th from the first pattern, and the distance l_m-1 between the first pattern and the third pattern arranged m-1-th from the first pattern satisfy the following equation, and l_m=d2tan(α)+l_m-1+ tan(β_m-1)+ tan(β_m) A light guide device characterized in that, where d2 is the thickness of the adhesive layer, α is the directional angle of the illumination light reflected by the plurality of patterns, β_m is the inclination angle of the inclined surface of the second pattern, and β_m-1 is the inclination angle of the inclined surface of the third pattern.

15. In Paragraph 1, Among the plurality of patterns above, the inclination angle β_m of the inclined surface of the second pattern arranged m-th from the first pattern, from the first pattern where the incident angle of the illumination light is 0°, satisfies the following equation, and (β_m)=90°-(Φ3_m-α) / 2 A light guide device characterized in that, here, α is the directional angle of the illumination light directed by a plurality of patterns, and Φ3_m is the directional angle of the illumination light within the patterned layer.

16. In Paragraph 1, A light guide device characterized in that the above-described coupling element further includes a reflective layer on the patterned layer.

17. In Paragraph 16, A light guide device characterized in that the directional angle of the illumination light reflected from the interface between the reflection layer and each of the plurality of patterns is the same.

18. In Paragraph 1, A light guide device characterized in that the refractive index of the patterned layer is in the range of 1.5 to 2.

19. Transparent layer; and It includes an coupling element comprising a patterned layer on the above transparent layer; The above patterned layer includes a plurality of patterns including inclined surfaces, and The spacing between the above plurality of patterns is different from each other, and A light guide device characterized in that the angle of inclination of each of the above-mentioned plurality of patterns is different from each other.

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