Patent Description:
A light guide structure is commonly found in a light guide plate, and the light guide plate is a high-tech product for converting a linear light source into a surface light source. Light guide spots are printed on the bottom surface of an optical-grade acrylic/PC plate by using an engraving printing technology. The light emitted from the light source is absorbed by the optical-grade acrylic plate and is continuously and totally reflected inside the plate, when the light irradiates each light guide spot, the reflected light can be diffused at various angles, and then emitted from the front surface of the light guide plate after breaking the reflection condition. The light guide plate can emit light uniformly through various light guide spots with different densities and sizes.

The light guide plate is high in manufacturing cost and precise in optical structure, and the whole light guide plate needs to be wasted once being damaged. Currently, the light guide plate is replaced by combining a light guide film with a transparent substrate, such as Chinese patent application with the publication number of <CIT>, a composite light guide plate is disclosed, which has a transparent substrate and a transparent film, and a plurality of light guide spots are printed on the transparent film and attached to the back surface of the transparent substrate. The above solution is to print the light guide spots on the transparent film firstly, and then combine the transparent film printed with the light guide spots with the transparent substrate, to form the composite light guide plate. Since the light guide spots are printed on the transparent thin film, it is easier to implement than direct printing on the transparent substrate, which reduces manufacturing difficulty, and even if bad scrapping occurs, only the part of the transparent film needs to be scrapped while the part of the transparent substrate is intact, so that the cost can be reduced.

The patent No. <CIT> discloses a controlled light distribution element, which comprises a lightguide medium configured for light propagation, a first functional layer configured as an optical filter layer and disposed on an at least one surface of the lightguide medium,and a second functional layer comprising an at least one optically functional pattern, wherein the first functional layer and the second functional layer are rendered with an at least one optical function related to incident light and,in particular, to light incident at an angle equal and/or below the critical angle.

The patent No. <CIT> discloses a light distribution structure and a related element <NUM>, such as a light guide. The structure <NUM> is preferably an optically functional layer comprising an at least one feature pattern <NUM>, 11A established in a light-transmitting carrier by a plurality of three-dimensional optical features variable in terms of at least one of the cross-sectional profile, dimensions, periodicity. orientation and disposition thereof within the feature pattern. In some instances, the optical features are embodied as internal optical cavities <NUM> capable to establish the total internal reflection (TIR) function at a horizontal surface and at an essentially vertical surface thereof. A method for manufacturing the light distribution structure is further provided.

The patent No. <CIT> discloses an optical device which realizes uniform light distribution and sufficient display quality with a simple structure. The optical device has light guide layer, a first optical functional layer, a light control structure.

The patent No. <CIT> discloses a system and method for using bubble structures to control the extraction of light from a waveguide top surface. The method determines a maximum angle (a) of light propagation through a waveguide medium relative to a first horizontal direction parallel to a waveguide top surface. A plurality of bubble structures is provided having a refractive index less than the waveguide medium. The bubble structures have a base, and sides formed at an acute angle upwards with respect to the base. The bubble structure bases are separated by gap (W), have a height (H), and have a top separated from a waveguide top surface by a space (h). The method varies the gap (W), the height (H), and the space (h). In response, the intensity oflight extraction at even the maximum angle (α) of light propagation, can be controlled from the waveguide top surface.

The patent No. <CIT> is directed to techniques to manufacture internal cavity optical patterns and to apparatuses manufactured using the manufacturing techniques. Internal cavity optical patterns include small cavities (e.g., microcavities, nanocavities, etc.) spread across a surface of a thin transparent material. The thin material may then be laminated to a second material to join the surface having the cavities with the second material and thereby enclose the cavities within the resulting combination. The internal cavities may be filled with air or another medium (e.g., a fluid, gas, or solid), which enable the cavity to redirect light in accordance with design requirements. By manufacturing the internal cavity optics in this manner, the cavities may remain free of debris that may reduce an effectiveness of the optics. In some instances, additional layers of material may be laminated together to create additional layers of the internal cavity optics.

However, the above-mentioned solution has certain drawbacks, because the transparent film and the transparent substrate are separately arranged, the firmness of the bonding between the transparent film and the transparent substrate should be considered when the transparent film and the transparent substrate are bonded. The light guide points are arranged on the transparent film, when the surface with the light guide points on the transparent film is in contact with the transparent substrate, not the surface-to-surface bonding but the point-to-surface bonding is adopted between the two. Although there are a lot of light guide points, the transparent film and the transparent substrate are not made of the same material, and the point-to-surface bonding is easy to separate, which is not beneficial for long-term use.

In view of the disadvantages present in the prior art, this application provides a light guide film, a production method thereof and a light guide device, which can improve the bonding area and intensity between the light guide film and the substrate, and better protect the ultrastructure without affecting the light guiding effect.

To this end, this application provides the following technical solutions: a light guide film is provided, an upper surface of the light guide film is a light exit surface and a lower surface is a light incident surface; the lower surface of the light guide film is smooth, and used for being connected with a transparent substrate; a plurality of hollow ultrastructures are disposed in the light guide film, each hollow ultrastructure includes a conduction reflecting surface close to the lower surface of the light guide film, a top surface close to the upper surface of the light guide film, and a light exit reflecting surface connecting the conduction reflecting surface and the top surface, and a gap between every two adjacent ultrastructures is a light exit gap, a distance between the bottom line of the conduction reflecting surface and the light incident surface is <NUM>-<NUM>, the conduction reflecting surface is a curved surface, and an included angle between a tangent plane at any point on the curved surface and the light incident surface is less than <NUM>°, and the light guide film is made of a soft material.

Compared with the prior art, the lower surface of the light guide film is smoothly arranged, so that when the lower surface of the light guide film is fixed with the substrate, the whole surface can be bonded, the contact area is maximized, the fixing effect can also be optimized, and the light guide film and the substrate are not easy to separate.

In the present application, a hollow ultrastructure is arranged inside the light guide film, so that light can be guided, light directly emitted to the hollow ultrastructure from the substrate can be totally reflected, light emitted to the light exit gap from the substrate can be finally emitted from the light exit surface, thereby achieving the light guide function. Furthermore, the ultrastructure of the light guide is arranged inside the light guide film, so that the ultrastructure for light guide is not easy to damage and has stronger stretch-resistant capability.

The hollow ultrastructure is sealed by the conduction reflecting surface, the top surface and the light exit reflecting surface, and the interior of the hollow ultrastructure is air, or other material having a large difference from the refractive index of the film material, and light emitted to the conduction reflecting surface may be totally reflected, and the optical path extends within the substrate. Light emitted to the light exit gap is emitted onto the light exit reflecting surface, and then reflected and emitted from the light exit surface. A plurality of hollow ultrastructures are arranged inside the light guide film to play a role of guiding light, and the included angle between the light reflecting surface and the light exit reflecting surface, and the size of the light exit gap are controlled, so as to control the light path, and light rays are gradually distributed on the light exit surface of the whole light guide film.

According to the claimed invention, the conduction reflecting surface is a curved surface, the included angle between a tangent plane at any point on the curved surface and the light incident surface is less than <NUM>°.

By adopting the above technical solution, when the conduction reflecting surface is a flat surface, the conduction reflecting surface can be parallel to the light incident surface, and the reflection path of light is regular. When the conduction reflecting surface is a curved surface, the light path is irregular, and different light guiding effects and differentiated visual effects are generated.

Preferably, the light exit reflecting surface is an inclined surface or a curved surface; when the light exit reflecting surface is an inclined surface, the included angle between the light exit reflecting surface and the light incident surface is <NUM>° to <NUM>°; when the light exit reflecting surface is a curved surface, the included angle between a tangent plane at any point on the curved surface and the light incident surface is <NUM>° to <NUM>°.

By adopting the above technical solution, when light rays are irradiated on the inclined surface, the light rays are reflected and then irradiated on the light exit surface, and since the angles of the light irradiated on the inclined surface are different, the angles of the light irradiated on the light exit surface after being reflected are also different, and the intensity of the light emitted is different. If the light exit reflecting surface is arranged as a cambered surface, the angle of the cambered surface is arranged in advance, such that the light rays are vertically emitted to the light exit surface as much as possible, after the light lays are reflected by the cambered surface, so that light rays emitted from the light exit surfaces reaches the maximum light intensity, substantially remains uniform, and the light rays are emitted more uniformly.

The distance between the bottom line of the conduction reflecting surface and the light incident surface is <NUM>-<NUM>, and the bottom lines of all the conduction reflecting surfaces are equidistant or non-equidistant from the light incident surface.

In the prior art, the ultrastructure is arranged on the surface of the light guide film, and light rays pass through the substrate and then are directly emitted to the ultrastructure, so that the light utilization efficiency is very high. However, in the present application, in order to achieve a better bonding effect between the light guide film and the substrate, the ultrastructure is arranged inside the light guide film, therefore, the ultrastructure and the substrate are spaced apart by a thin layer of light guide film, which has a certain influence on the light path, and light needs to pass through the thin layer of film before reaching the ultrastructure. Therefore, the thinner the thin layer of film, the smaller the effect of the thin film on light refraction, the smaller the change of the light path; generally, when the thickness of the thin film is less than <NUM>, and the light path change is negligible.

Preferably, the light exit gap between every two adjacent ultrastructures are equidistant or non-equidistant.

The light exit gap between ultrastructures can be equidistant or non-equidistant, if equidistant, the light emission is relatively uniform; and if non-equidistant, the light guiding efficiency of each light exit gap can be changed, so that the light finally emitted from the light guide film is significantly changed, and the visual effect is better.

This application further provides a process for producing a light guide film, which includes the following steps of:.

The polymer material can be selected from transparent silicone, or other transparent thermosetting or thermoplastic polymer materials, and an integrally formed light guide film, the process is simpler, and the hollow ultrastructure is arranged inside the light guide film, and is not easily damaged by itself and has a stronger stretch-resistant capability while guiding light.

Since the ultrastructure is disposed inside the light guide film, it is difficult to form at a time through a single mold. The mold is divided into two parts, and the light guide film is divided into two parts, which are respectively formed. Before the two materials are completely cured, the two materials are attached by utilizing the characteristics of the silica gel material, so that curing forming is realized.

Preferably, the upper die or the lower die is provided with a micro-structure matching with the ultrastructure.

The precision of the ultrastructure is too high. If the upper die and the lower die each has a part of the ultrastructure, the precise bonding cannot be ensured when the last two parts of the finished product are bonded, the ultrastructure is easily displaced, which affects the light guiding effect. Therefore, the micro-structure is individually disposed in the upper die or the lower die, so that one of the molded finished products has an ultrastructure and can be bonded to another finished product, thereby ensuring accuracy of the ultrastructure.

By adopting the above technical solution, the light guide film can be formed at a time through a single mold, the process is simpler, the molding effect is better, and the light guide film is not easily deformed.

This application further provides a light guide device, which includes the light guide film described above, and further includes a transparent substrate, wherein a lower surface of the light guide film is fixed to the transparent substrate.

By adopting the above technical solution, since the lower surface of the light guide film is a smoothly transitioned flat surface, so that when the light guide film is fixed to the substrate, the whole surface can be attached, the contact area reaches the maximum, the fixing effect can be optimized, and the light guide film and the substrate are not easy to separate.

Preferably, a protective layer is arranged on the upper surface of the light guide film.

By adopting the above technical solution, the light guide film is made of a soft material and is easily stained with dirt such as dust, the light emitting effect can be improved by additionally arranging the protective layer, and cleaning is also convenient. The protection layer is preferably made of PET, and the PET is good in light transmittance, good in bonding effect with a silica gel light guide film, stable in physical performance and not prone to abrasion and deformation.

In summary, the present application has the following beneficial effects: the lower surface of the light guide film is smoothly arranged, so that when the lower surface of the light guide film is fixed with the substrate, the whole surface can be bonded, the contact area is maximized, the fixing effect can also be optimized, and the light guide film and the substrate are not easy to separate. Meanwhile, the ultrastructure is arranged inside the light guide film, so that light can be guided, the ultrastructure is not easy to damage and has stronger stretch-resistant capability.

In the drawings: <NUM>. substrate; <NUM>. protective layer; <NUM>. light guide film; <NUM>. light incident surface; <NUM>. light exit surface; <NUM>. Ultrastructure; <NUM>. conduction reflecting surface; <NUM>. light exit gap; <NUM>. top surface; <NUM>. light exit reflecting surface; <NUM>. upper die; <NUM>. lower die; <NUM>. micro-structure.

Hereinafter, the present application is further illustrated in detail in combination with the accompanying drawings.

Referring to <FIG>, a light guide film <NUM> is provided, an upper surface of the light guide film <NUM> is a light exit surface <NUM>, and a lower surface of the light guide film <NUM> is a light incident surface <NUM>. The lower surface of the light guide film <NUM> is smooth and is used for being fixedly connected with the substrate <NUM> (see <FIG>). A plurality of hollow ultrastructures <NUM> are disposed in the light guide film <NUM>, and a side of the hollow ultrastructures <NUM> close to the lower surface of the light guide film <NUM> is a conduction reflecting surface <NUM>, and a gap between every two adjacent ultrastructures <NUM> is a light exit gap <NUM>.

In this embodiment, the lower surface of the light guide film <NUM> is arranged to be smooth, so that when the light guide film <NUM> is fixed to the substrate <NUM>, the whole surface can be attached, the contact area reaches the maximum, the fixing effect can be optimized, and the light guide film <NUM> and the substrate <NUM> are not easy to separate.

In this embodiment, the hollow ultrastructure <NUM> includes a conduction reflecting surface <NUM> close to the lower surface of the light guide film <NUM>, a top surface <NUM> close to the upper surface of the light guide film <NUM>, and a light exit reflecting surface <NUM> connecting the conduction reflecting surface <NUM> and the top surface <NUM>.

The hollow ultrastructure <NUM> is disposed inside the light guide film <NUM>, so that light can be guided, light directly emitted from the substrate <NUM> to the hollow ultrastructure <NUM> can be totally reflected, light emitted from the substrate <NUM> to the light exit gap <NUM> can be finally emitted from the light exit surface <NUM>, thereby achieving the light guide function. Furthermore, the light guide ultrastructure is disposed inside the light guide film <NUM>, so that the light guide film <NUM> is not easy to damage and stronger in stretch-resistant capability. The hollow ultrastructure <NUM> is sealed by the conduction reflecting surface <NUM>, the top surface <NUM> and the light exit reflecting surface <NUM>, and the interior of the hollow ultrastructure <NUM> is air, or other material having a large difference from the refractive index of the film material, and light emitted to the conduction reflecting surface <NUM> may be totally reflected, and the optical path extends within the substrate <NUM>. Light emitted to the light exit gap <NUM> is emitted onto the light exit reflecting surface <NUM>, and then reflected and emitted from the light exit surface <NUM>. A plurality of hollow ultrastructures <NUM> are arranged inside the light guide film <NUM> to play a role of guiding light, and the included angle between the light reflecting surface <NUM> and the light exit reflecting surface <NUM>, and the size of the light exit gap <NUM> are controlled, so as to control the light path, and light rays are gradually distributed on the light exit surface <NUM> of the whole light guide film <NUM>.

In this embodiment, since the top surface <NUM> has no light guiding effect, the top surface <NUM> can be designed in any shape, such as a flat surface, a cambered surface, a dot, or the like, as shown in <FIG>.

In this embodiment, the light exit gaps <NUM> between the ultrastructures <NUM> may be equidistant or non-equidistant, as shown in <FIG>.

As shown in <FIG>, the conduction reflecting surface <NUM> may be a flat surface, in embodiments not part of the claimed invention, or a curved surface, in embodiments according to the claimed invention, and an included angle between a tangent plane at any point on the curved surface and the light incident surface is less than <NUM>°. The light distribution can be achieved according to different designs, so that there is a sense of hierarchy when light is emitted.

As shown in <FIG>, light is incident into the substrate <NUM> from the side surface of the substrate <NUM>, and there are three cases of light path.

The first one is that the light rays are emitted to the junction between the substrate <NUM> and the light guide film <NUM>, refracted into the light guide film <NUM>, and then emitted to the light exit gap <NUM> between light guide structures in the light guide film <NUM>, and the light continues to pass through the light exit gap <NUM> and is emitted to the light exit reflecting surface <NUM>. Since the other side of the light exit reflecting surface <NUM> is a hollow ultrastructure <NUM>, the refractive index of the air is low, the light rays are totally reflected on the light exit reflecting surface <NUM> and are emitted from the light exit surface <NUM>.

The second one is that the light rays are emitted to the junction between the substrate <NUM> and the light guide film <NUM>, refracted into the light guide film <NUM>, and then emitted to the lower surface of the hollow ultrastructure <NUM> in the light guide film <NUM>, that is, the conduction reflecting surface <NUM>. Since the other side of the conduction reflecting surface <NUM> is a hollow ultrastructure <NUM>, the refractive index of the air is low, the light rays are totally reflected on the conduction reflecting surface <NUM> and are emitted back to the substrate <NUM>. The light rays continue to be totally reflected on one side of the substrate <NUM> away from the light guide film <NUM>, and are emitted to the light guide film <NUM> again. If the light rays are emitted to the conduction reflecting surface <NUM> of the hollow ultrastructure <NUM> after passing through the light guide film <NUM>, the light rays continue to be totally reflected repeatedly; if the light rays are emitted to the light exit gap <NUM> between the light guide structures after passing through the light guide film <NUM>, the light rays are emitted from the light exit surface <NUM>, as with the first case described above.

The third one is that the light rays are emitted to the one side of the substrate <NUM> away from the light guide film <NUM>, and then are emitted to the light guide film <NUM> after being totally reflected, if the light rays are emitted to the light exit gap <NUM> between the light guide structures after passing through the light guide film <NUM>, then the light rays are as with the first case described above; if the light rays are emitted to the conduction reflecting surface <NUM> of the hollow ultrastructure <NUM> after passing through the light guide film <NUM>, then the light rays are as with the second case described above.

In this embodiment, the distance between the conduction reflecting surface <NUM> and the light incident surface <NUM> is <NUM>-<NUM>.

In the prior art, the ultrastructure <NUM> is arranged on the surface of the light guide film <NUM>, and light rays pass through the substrate <NUM> and then are directly emitted to the ultrastructure <NUM>, so that the light utilization efficiency is very high. However, in the present application, in order to achieve a better bonding effect between the light guide film <NUM> and the substrate <NUM>, the ultrastructure <NUM> is arranged inside the light guide film <NUM>, therefore, the ultrastructure <NUM> and the substrate <NUM> are spaced apart by a thin layer of light guide film <NUM>, which has a certain influence on the light path, and light needs to pass through the thin layer of film before reaching the ultrastructure <NUM>. Therefore, the thinner the thin layer of film, the smaller the effect of the thin film on light refraction, the smaller the change of the light path; generally, when the thickness of the thin film is less than <NUM>, and the light path change is negligible.

In this embodiment, the distance between the conduction reflecting surface <NUM> and the light incident surface <NUM> is <NUM>-<NUM>, preferably <NUM>. The distance has certain influence on the light path, and after the light passes through the substrate <NUM>, the light needs to be emitted to the conduction reflecting surface <NUM> or the light exit gap <NUM> only after passing through the small distance. Therefore, the shorter the distance, the smaller the effect of the thin film on light refraction, the smaller the change of the light path; when the thickness of the thin film is less than <NUM>, and the light path change is negligible.

The height of the conduction reflecting surface <NUM> to the light incident surface <NUM> of each ultrastructure <NUM> may be uniform or non-uniform, if uniform, the light emission is relatively uniform; and if non-uniform, as shown in <FIG>, different light guiding effects and differentiated visual effects are generated.

In this embodiment, as shown in <FIG>, the conduction reflecting surface <NUM> may be a flat surface or a curved surface. When the conduction reflecting surface <NUM> is a flat surface, the conduction reflecting surface <NUM> can be parallel to the light incident surface, and the reflection path of light is regular. When the conduction reflecting surface <NUM> is a curved surface, the included angle between a tangent plane at any point on the curved surface and the light incident surface is less than <NUM>°, the light path is irregular, the light distribution can be achieved according to different designs, and different light guiding effects and differentiated visual effects are generated.

This embodiment differs from Embodiment <NUM> in that, in this embodiment, the light exit reflecting surface <NUM> is a cambered surface.

Referring to <FIG>, it is shown a light emitting path when the light exit reflecting surface <NUM> is an inclined surface in Embodiment <NUM>. When light rays are irradiated on the inclined surface, the light rays are reflected and then irradiated on the light exit surface <NUM>, and since the angles of the light irradiated on the inclined surface are different, the angles of the light irradiated on the light exit surface <NUM> after being reflected are also different, and the intensity of the light emitted is different.

In this embodiment, as shown in <FIG>, the light exit reflecting surface <NUM> is arranged as a cambered surface. When the light exit reflecting surface is a curved surface, the included angle between a tangent plane at any point on the curved surface and the light incident surface is <NUM>° to <NUM>°. The angle of the cambered surface is designed such that the light rays are vertically emitted to the light exit surface <NUM> as much as possible, after the light lays are reflected by the cambered surface, so that light rays emitted from the light exit surfaces <NUM> reaches the maximum light intensity, substantially remains uniform, and the light rays are emitted more uniformly.

In this embodiment, the height of the light exit reflecting surface <NUM> is <NUM>-<NUM> times of the light exit gap <NUM>, so that the number of the light exit gaps <NUM> that light passes through can be controlled, thus the light reflected out of the light guide film from the light exit reflecting surface <NUM> can be controlled, and the light emitting efficiency of the light guide film can be controlled.

This embodiment provides a production process of a hollow ultrastructure light guide film, which is used for producing the light guide film of Embodiment <NUM>, and the production process includes the following steps of:.

An integrally formed light guide film, the process is simpler, and the hollow ultrastructure is arranged inside the light guide film, and is not easily damaged by itself and has a stronger stretch-resistant capability while guiding light.

This embodiment differs from Embodiment <NUM> in that, the light guide film is formed by hollow extrusion molding. The mold includes a micro-structure core mold, the raw materials are molded in the mold, and then stretched after leaving a die orifice, to obtain the light guide film with a hollow ultrastructure. The light guide film can be formed at a time through a single mold, the process is simpler, the molding effect is better, and the light guide film is not easily deformed.

As shown in <FIG>, this embodiment differs from Embodiment <NUM> in that, in this embodiment, the mold includes an upper die <NUM> and a lower die <NUM>, and after the raw materials are respectively injected into the upper die <NUM> and the lower die <NUM>, the semi-finished raw materials are removed from the mold after the raw materials are semi-formed, and the semi-finished raw materials are bonded to each other before being fully cured.

In this embodiment, the upper die <NUM> or the lower die <NUM> is provided with a micro-structure <NUM> matching with the ultrastructure.

The precision of the ultrastructure is too high. If the upper die <NUM> and the lower die <NUM> each has a part of the ultrastructure, the precise bonding cannot be ensured when the last two parts of the finished product are bonded, the ultrastructure is easily displaced, which affects the light guiding effect. Therefore, the micro-structure <NUM> is individually disposed in the upper die <NUM> or the lower die <NUM>, so that one of the molded finished products has an ultrastructure and can be bonded to another finished product, thereby ensuring accuracy of the ultrastructure. In this embodiment, the micro-structure <NUM> is provided in the upper die <NUM>.

As shown in <FIG>, this embodiment discloses a light guide structure, which adopts the light guide film <NUM> of Embodiment <NUM>, and further includes a transparent substrate <NUM> and a protective layer <NUM>. The lower surface of the light guide film <NUM> is fixed with the transparent substrate <NUM>, and a protective layer <NUM> is arranged on the upper surface of the light guide film <NUM>.

The light guide film <NUM> is made of a soft material and is easily stained with dirt such as dust, the light emitting effect can be improved by additionally arranging the protective layer <NUM>, and cleaning is also convenient. The protection layer <NUM> is preferably made of PET, and the PET is good in light transmittance, good in bonding effect with a silica gel light guide film, stable in physical performance and not prone to abrasion and deformation.

In addition, during processing, the protective layer <NUM> can be firstly attached to the light guide film <NUM>, so that the hardness and strength of the light guide film can be increased. Then, the light guide film <NUM> is attached to the substrate <NUM>, so that the light guide film <NUM> is not easily deformed when bonding.

Claim 1:
A light guide film, wherein an upper surface of the light guide film (<NUM>) is a light exit surface (<NUM>) and a lower surface is a light incident surface (<NUM>); the lower surface of the light guide film (<NUM>) is smooth and used for being connected with a transparent substrate (<NUM>); a plurality of hollow ultrastructures (<NUM>) are disposed in the light guide film (<NUM>), each hollow ultrastructure (<NUM>) comprises a conduction reflecting surface (<NUM>) close to the lower surface of the light guide film (<NUM>), a top surface (<NUM>) close to the upper surface of the light guide film (<NUM>), and a light exit reflecting surface (<NUM>) connected with the conduction reflecting surface (<NUM>) and the top surface (<NUM>), a gap between every two adjacent ultrastructures (<NUM>) is a light exit gap (<NUM>), and a distance between the bottom line of the conduction reflecting surface (<NUM>) and the light incident surface (<NUM>) is <NUM>-<NUM>; characterized in that
the conduction reflecting surface (<NUM>) is a curved surface, and an included angle between a tangent plane at any point on the curved surface and the light incident surface (<NUM>) is less than <NUM>°, and
the light guide film is made of a soft material.