Optical film

Abstract

An optical film comprises a first substrate and a plurality of prism structures. The plurality of prism structures are arranged on a first substrate surface of the first substrate along a first direction and extend along a second direction. A first side edge and a second side edge are arranged on the two opposite sides of the first substrate in the first direction respectively. Each prism structure has a structure height relative to the surface of the first substrate, and the structure height of each prism structure increases progressively and then decreases progressively from the first side edge to the second side edge.

Description

Technical Field

[0001] The invention relates to an optical film, and in particular to an optical film with a prism structure. Background Art

[0002] The advancement of display technology has driven the development of in-vehicle display applications. Head-up displays that use vehicle windshields as projection screens are one of the development focuses of related manufacturers. Generally speaking, the light source modules used in head-up displays are mostly equipped with prisms with light-collecting functions and brightening films that can improve the utilization rate of light energy, and have a certain degree of light uniformity. However, since the windshields of most vehicles are complex curved surfaces and the surface is usually provided with a special reflective coating, the reflective coating will further change the reflective properties of the windshield, causing light under different conditions (such as different polarization states, incident angles) to produce different reflectivities. Therefore, the uniform light emitted by the light source module is projected onto the windshield, and the virtual image produced by reflection is prone to poor display brightness uniformity. Summary of the invention

[0003] The invention provides an optical film which can effectively improve the brightness uniformity of the image formed after the light is reflected by the projection screen.

[0004] The invention provides an optical film, which has high process flexibility and a more uniform appearance of the film surface.

[0005] The optical film of the present invention is suitable for use in a light source module and is arranged corresponding to a projection screen. The projection screen has a viewing area consisting of a plurality of eye points. The optical film includes a first substrate and a plurality of prism structures. The first substrate is provided with a first side edge and a second side edge on opposite sides along a first direction. The plurality of prism structures are arranged on a first substrate surface of the first substrate along the first direction and extend along a second direction. The plurality of prism structures include a first prism structure and a second prism structure having different geometric shapes. The light source of the light source module is used to emit a first light and a second light. After passing through the first prism structure, the first light enters a first part of the projection screen according to a first light intensity. After passing through the second prism structure, the second light enters a second part of the projection screen according to a second light intensity. The first light intensity is not equal to the second light intensity. A portion of a virtual image formed by the first light with the first light intensity at any one of the plurality of eye points after being reflected by the first part of the projection screen has a first display brightness. Another portion of a virtual image formed by the second light with the second light intensity at any one of the plurality of eye points after being reflected by the second part of the projection screen has a second display brightness. The first display brightness is equal to the second display brightness.

[0006] The optical film of the present invention comprises a first substrate and a plurality of prism structures. The plurality of prism structures are arranged on the first substrate surface of the first substrate along a first direction and extend along a second direction. The first substrate is provided with a first side edge and a second side edge on opposite sides along the first direction. Each prism structure has a structural height relative to the surface of the first substrate, and the structural height of each prism structure increases first and then decreases from the first side edge to the second side edge.

[0007] The optical film of the present invention comprises a substrate and a plurality of prism structures. The substrate is provided with a first side edge and a second side edge on opposite sides along a first direction. The plurality of prism structures are arranged on a first substrate surface of the substrate along the first direction and extend along a second direction. Each prism structure has a structural height relative to the substrate surface. Each prism structure has a first structural surface and a second structural surface facing the first side edge and the second side edge respectively. A first angle is formed between the first structural surface and the substrate surface. A second angle is formed between the second structural surface and the substrate surface. The prism structures comprise a plurality of first prism structures, a plurality of second prism structures and a plurality of third prism structures. At least a portion of a plurality of third prism structures is provided between each first prism structure and each second prism structure. The first angle of each third prism structure is equal to the first angle of each first prism structure and is not equal to the first angle of each second prism structure. The second angle of each third prism structure is equal to the second angle of each first prism structure and is not equal to the second angle of each second prism structure. The structural height of each third prism structure is less than the structural height of each of the plurality of first prism structures and the plurality of second prism structures.

[0008] Based on the above, in an optical film of one embodiment of the present invention, the geometric shape or structural height of each prism structure may be different depending on its setting position on the substrate. The geometric shape distribution or structural height distribution of these prism structures can allow the light passing through each structural surface to be incident on different parts of the projection screen with different light intensities. The virtual image formed by any eye point in the viewing area after the light is reflected by different parts of the projection screen can have a more uniform display brightness distribution. In an optical film of one embodiment of the present invention, a third prism structure is provided between the first prism structure and the second prism structure having different angles. Since the angle of the third prism structure is the same as that of the first prism structure or the second prism structure and the structural height is lower than that of the first prism structure and the second prism structure, the setting area of ​​the third prism structure can be used as a buffer area for the first prism structure and the second prism structure during segmented processing, which helps to improve the process flexibility, and the optical film produced can have a good film surface appearance. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1A and Figure 1B is a schematic cross-sectional view of a light source module according to a first embodiment of the present invention.

[0010] Figure 2 1 is a schematic top view of the configuration relationship between the optical film and the projection screen.

[0011] Figure 3A yes Figure 2 Schematic diagram of the configuration relationship between the optical film, projection screen and viewing area.

[0012] Figure 3B yes Figure 2 Another embodiment of the optical film, and a schematic diagram of the configuration relationship between the projection screen and the viewing area.

[0013] FIG. 4A to FIG. 4C It is the light distribution after the light passes through the various prism structures in different areas of the optical film in FIG. 1 .

[0014] Figure 5A It is the display brightness distribution of the virtual image formed at one eye point in the viewing area after the light passes through the optical film in FIG. 1 and is reflected by the projection screen.

[0015] Figure 5B The display brightness distribution of a virtual image formed at one eye point in the viewing area after light passes through an optical film of a comparative example and is reflected by a projection screen.

[0016] Fig. 6A and Figure 6B is a cross-sectional schematic diagram of an optical module of a comparative example.

[0017] Figure 7 yes Figure 1A A cross-sectional schematic diagram of another embodiment of an optical film.

[0018] Fig. 8A and Figure 8B is a schematic cross-sectional view of a light source module according to a second embodiment of the present invention.

[0019] 9A to 9C It's the light passing through Fig. 8A and Figure 8B The optical film has multiple prism structures in different areas and light distribution after the light type bias film.

[0020] Fig. 10A and Fig. 10B is a schematic cross-sectional view of a light source module according to a third embodiment of the present invention.

[0021] Fig.11 is a schematic cross-sectional view of a light source module according to a fourth embodiment of the present invention.

[0022] Fig.12 yes Fig.11 Schematic diagram of the configuration relationship between the optical film, projection screen and viewing area.

[0023] Fig.13 is a schematic cross-sectional view of an optical film according to a fifth embodiment of the present invention.

[0024] Fig.14 yes Fig.13 A cross-sectional schematic diagram of another embodiment of an optical film.

[0025] Fig.15 is a schematic cross-sectional view of an optical film according to a sixth embodiment of the present invention.

[0026] Description of reference numerals:

[0027] 10, 10A, 10B, 10C, 11: Light source module

[0028] 50: Light source

[0029] 60: Diffuser

[0030] 100, 100", 100A, 100C, 100D, 100E, 100F, 130: Optical film

[0031] 101, 101”, 131, 141, 151, 171: base plate

[0032] 101e1, 101e2, 131e1, 131e2, 171e1, 171e2: side edge

[0033] 101s, 101s”, 131s, 171s: Substrate surface

[0034] 120, 120A, 121~125, 121", 122", 121A", 122A", 135, 143, 153: Prism structure

[0035] 140, 150: Prism

[0036] 160: Optical Brightness Enhancement Film

[0037] 170: Optical bias film

[0038] 173: Optical microstructures

[0039] 200: Projection screen

[0040] 200p1~200p5:Part

[0041] A1, A2, A1”, A2”, A1a, A2a, A1a”, A2a”, A1b, A2b, A1b”, A2b”, A3, A4: included angle

[0042] CP: Midpoint

[0043] EP: Eye Point

[0044] H, H1, H1”, H2, H2”: structure height

[0045] IL, IL”: intersection line

[0046] IM: virtual image

[0047] IMa~IMe: Partial virtual image

[0048] L1~L5: light

[0049] P1, P2: Pitch

[0050] ss1, ss2, ss1”, ss2”, ss3, ss4: structural surface

[0051] SX, SX”: Structural axis

[0052] USR1, USR2: User

[0053] VA, VA”: Viewing area

[0054] VP: Virtual Facade

[0055] VX1, VX2: upright center axis

[0056] W1a, W1b, W2a, W2b: Width

[0057] X, Y, Z: direction DETAILED DESCRIPTION

[0058] As used herein, "about," "approximately," "substantially," or "substantially" include the stated value and the average value within an acceptable deviation range of the particular value determined by one of ordinary skill in the art, taking into account the measurement in question and the particular amount of error associated with the measurement (i.e., the limitations of the measurement system). For example, "about" can mean within one or more standard deviations of the stated value, or within, for example, ±30%, ±20%, ±15%, ±10%, ±5%. Furthermore, as used herein, "about," "approximately," "substantially," or "substantially" can select a more acceptable deviation range or standard deviation depending on the measured property, cutting property or other property, and can apply to all properties without one standard deviation.

[0059] In the accompanying drawings, for the sake of clarity, the thickness of layers, films, panels, regions, etc. is magnified. It should be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" or "connected to" another element, it may be directly on or connected to another element, or an intermediate element may also exist. On the contrary, when an element is referred to as being "directly on" or "directly connected to" another element, there is no intermediate element. As used herein, "connection" may refer to physical and / or electrical connection. Furthermore, "electrical connection" may be the presence of other elements between two elements.

[0060] In addition, relative terms such as "lower" or "bottom" and "upper" or "top" may be used herein to describe the relationship of one element to another element, as shown in the figures. It should be understood that relative terms are intended to include different orientations of the device in addition to the orientation shown in the figures. For example, if the device in one figure is turned over, the element described as being on the "lower" side of the other elements will be oriented on the "upper" side of the other elements. Therefore, the exemplary term "lower" can include both "lower" and "upper" orientations, depending on the specific orientation of the figure. Similarly, if the device in one figure is turned over, the element described as being "below" or "below" other elements will be oriented as being "above" other elements. Therefore, the exemplary terms "above" or "below" can include both above and below orientations.

[0061] Exemplary embodiments are described herein with reference to cross-sectional views that are schematic diagrams of idealized embodiments. Therefore, variations in the shapes of the illustrations as a result of, for example, manufacturing techniques and / or tolerances can be expected. Therefore, the embodiments described herein should not be construed as limited to the specific shapes of the regions as shown herein, but rather include shape deviations, for example, caused by manufacturing. For example, a region shown or described as flat may typically have rough and / or nonlinear features. In addition, the sharp angles shown may be rounded. Therefore, the regions shown in the figures are schematic in nature, and their shapes are not intended to illustrate the precise shapes of the regions and are not intended to limit the scope of the claims.

[0062] Reference will now be made in detail to exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals are used in the drawings and the description to refer to the same or like parts.

[0063] Figure 1A and Figure 1B is a schematic cross-sectional view of a light source module according to a first embodiment of the present invention. Figure 2 1 is a schematic top view of the configuration relationship between the optical film and the projection screen. Figure 3A yes Figure 2 Schematic diagram of the configuration relationship between the optical film, projection screen and viewing area. Figure 3B yes Figure 2 Another embodiment of the optical film, and a schematic diagram of the configuration relationship between the projection screen and the viewing area. FIG. 4A to FIG. 4C It is the light distribution after the light passes through the various prism structures in different areas of the optical film in FIG. 1 . Figure 5A It is the display brightness distribution of the virtual image formed at one eye point in the viewing area after the light passes through the optical film in FIG. 1 and is reflected by the projection screen. Figure 5B The display brightness distribution of a virtual image formed at one eye point in the viewing area after light passes through an optical film of a comparative example and is reflected by a projection screen. Fig. 6A and Figure 6B is a cross-sectional schematic diagram of an optical module of a comparative example. Figure 7 yes Figure 1A A cross-sectional schematic diagram of another embodiment of an optical film. For the sake of clarity, Figure 2 The light source module 10 is only shown Figure 1A An optical film 100 is provided.

[0064] Please refer to Figure 1A and Figure 1B The optical film 100 includes a substrate 101 and a plurality of prism structures 120. These prism structures 120 are arranged on a substrate surface 101s of the substrate 101, for example, along a direction X, and extend along a direction Y, wherein the direction X and the direction Y may be selectively perpendicular to each other, but are not limited thereto. The substrate 101 is provided with a side edge 101e1 and a side edge 101e2 on opposite sides along the direction X, respectively. Each prism structure 120 has a structural surface ss1 and a structural surface ss2 facing the side edge 101e1 and the side edge 101e2, respectively. An angle A1 is formed between the structural surface ss1 and the substrate surface 101s. An angle A2 is formed between the structural surface ss2 and the substrate surface 101s.

[0065] It is particularly noted that the structural surface of the prism structure 120 of the optical film 100 can have a variety of angles relative to the substrate surface 101s. For example, in the present embodiment, the substrate 101 is provided with a prism structure 121, a prism structure 122, a prism structure 123, a prism structure 124 and a prism structure 125 in sequence from one side edge 101e1 to the other side edge 101e2. These prism structures are symmetrically arranged relative to the structural center axis SX on the substrate surface 101s, and the structural center axis SX is parallel to the direction Y. It is first explained that the structural center axis SX of the present embodiment is also the symmetry axis of the substrate 101 in the direction X, but it is not limited to this.

[0066] The angle A1 of each of the plurality of prism structures 121 to 125 decreases from the side edge 101e1 to the side edge 101e2, and the angle A2 decreases from the side edge 101e2 to the side edge 101e1. For example, the angle A1 of the prism structure 122 farther from the side edge 101e1 is smaller than the angle A1 of the prism structure 121 closer to the side edge 101e1, and the angle A2 of the prism structure 121 farther from the side edge 101e2 is smaller than the angle A2 of the prism structure 122 closer to the side edge 101e2.

[0067] From another point of view, the structural height H of each of these prism structures relative to the substrate surface 101s will first increase and then decrease from the side edge 101e1 of the substrate 101 to the side edge 101e2. In other words, the structural height H of each prism structure decreases along the structural center axis SX toward the side edge 101e1 or the side edge 101e2 of the substrate 101. In this way, it can be ensured that these prism structures can be arranged on the substrate surface 101s with the same pitch, thereby avoiding the generation of moiré when the optical film 100 is stacked with other films to affect the visual effect.

[0068] However, the present invention is not limited thereto. Figure 7 As shown, in another variant embodiment, the angle A1 of the prism structure 120A of the optical film 100A increases from the structural center axis SX to the side edge 101e1 of the substrate 101, and the angle A2 of the prism structure 120A increases from the structural center axis SX to the side edge 101e2 of the substrate 101. On the other hand, the structural height H of the prism structure 120A increases along the direction from the structural center axis SX to the side edge 101e1 or the side edge 101e2 of the substrate 101.

[0069] First, it should be noted that when light passes through the optical film 100 (or Figure 7 The light field distribution after the optical film 100A) is anisotropic. For example, in the present embodiment, the aforementioned multiple prism structures 121-125 with five different angle designs can allow light to produce different light field distributions after passing through different areas of the optical film 100. The different areas here are, for example, five areas each having a plurality of prism structures 121-125, and each area having a plurality of prism structures with the same angle design. However, the present invention is not limited to this. In other embodiments, the number of angle types of the prism structure of the optical film can be adjusted according to actual application requirements (such as the number of partitions).

[0070] Please refer to Figures 1A to 3AThe optical film 100 is suitable for use in the light source module 10 and is disposed corresponding to a projection screen 200. In this embodiment, the projection screen 200 is, for example, a windshield or a window of a vehicle, and the light source module 10 and the projection screen 200 can be used together to form a head-up display (HUD) for use in a vehicle, but the present invention is not limited thereto. In other embodiments, the projection screen 200 can be a landscape window of a building.

[0071] For example, the light source module 10 may further include a light source 50, a diffuser 60, a prism sheet 150 and an optical brightness enhancement film 160. The light source 50 is suitable for emitting multiple light rays, such as light rays L1 to L5. The light source 50 is, for example, a light board having a plurality of light-emitting elements (such as light-emitting diodes) arranged in an array, but is not limited thereto. The optical film 100 is disposed on one side of the light-emitting surface of the light source 50 and is located on the transmission path of these light rays. The diffuser 60 may be selectively disposed between the optical film 100 and the light source 50. The optical brightness enhancement film 160 is disposed on the side of the optical film 100 facing away from the light source 50. The prism sheet 150 is disposed between the optical film 100 and the optical brightness enhancement film 160. The optical brightness enhancement film 160 is, for example, a reflective brightness enhancement film (dual brightness enhancement film, DBEF) produced by 3M, but is not limited thereto. In addition, a Cavity structure as disclosed in US8,390,760 may also be disposed between the diffuser 60 and the light source 50.

[0072] The prism sheet 150 may include a substrate 151 and a plurality of prism structures 153. In the present embodiment, the prism structures 153 may be arranged on the substrate 151 along a direction Y and extend along a direction X. In other words, the arrangement direction of the prism structures 153 of the prism sheet 150 may be perpendicular to the arrangement direction of the prism structures 120 of the optical film 100. It is particularly noted that, unlike the optical film 100, the two structural surfaces of the prism structures 153 of the prism sheet 150 are symmetrically arranged and are used to improve the light collection property of the light source module 10 in the direction Y.

[0073] For example, the light source module 10 can be disposed on a platform between the dashboard and the windshield of the vehicle and project a plurality of light beams L1-L5 toward the projection screen 200. After being reflected by the projection screen 200, the light beams L1-L5 are transmitted to a visual area VA formed by a plurality of eye points EP. After being received by any eye point EP in the visual area VA by the user USR1 (e.g., the driver) or the user USR2 (e.g., the passenger in the front passenger seat), the light beams L1-L5 will be imaged behind the projection screen 200, as shown in FIG. Figure 2 Virtual image IM shown.

[0074] In the present embodiment, the width of the viewing area VA along the direction X can cover both the user USR1 and the user USR2, but is not limited thereto. The projection screen 200 and the viewing area VA have a vertical central axis VX1 and a vertical central axis VX2, respectively, and the vertical central axis VX2 of the viewing area VA is opposite to the vertical central axis VX1 of the projection screen 200 along the direction Y. The vertical central axis VX1 and the vertical central axis VX2 can form a virtual vertical plane VP. The intersection line IL of the virtual vertical plane VP and the substrate surface 101s has a midpoint CP. The structural central axis SX passes through the midpoint CP of the intersection line IL and extends in the direction Y. More specifically, in the present embodiment, the structural central axis SX overlaps (or coincides with) the intersection line IL, but is not limited thereto.

[0075] In this embodiment, the projection screen 200 may include a plurality of parts 200p1-200p5. The plurality of light beams L1-L5 emitted by the light source 50 are respectively projected onto the plurality of parts 200p1-200p5 of the projection screen 200 after passing through the plurality of prism structures 121-125 of the optical film 100. After being respectively reflected by the plurality of parts 200p1-200p5 of the projection screen 200, the light beams L1-L5 respectively form a plurality of partial virtual images IMa-IMe constituting the aforementioned virtual image IM at any eye point EP of the viewing area VA.

[0076] First, since the projection screen 200 is a curved surface, different portions (e.g., portions 200p1 to 200p5) along the direction X have different reflectivities for light incident in the same direction, so light with a uniform light field distribution will form a non-uniform light field distribution after being reflected by the projection screen 200. Fig. 6A and Figure 6B ), another prism sheet 140 is used to replace the optical film 100 in the light source module 10 of this embodiment. Similar to the prism sheet 150, the prism sheet 140 may include a substrate 141 and a plurality of prism structures 143. In the comparative example, these prism structures 143 may be arranged on the substrate 141 along the direction X and extend along the direction Y. That is, the arrangement direction of the prism structure 143 of the prism sheet 140 may be perpendicular to the arrangement direction of the prism structure 153 of the prism sheet 150. The two structural surfaces of the prism structure 143 of the prism sheet 140 are symmetrically arranged and are used to improve the light collection property of the light source module 11 in the direction X.

[0077] The stacking of the prism sheet 140 and the prism sheet 150 allows the light emitted by the light source module 11 of the comparative example to have better light collection properties along the direction X and the direction Y, and the light field distribution is also more uniform. Figure 2After the projection screen 200 reflects light to any eye point EP, its light field distribution becomes uneven. After the light with uneven light field distribution forms a virtual image IM at any eye point EP in the viewing area VA, the display brightness of multiple parts of the virtual image will be significantly different. Figure 2 and Figure 5B As shown, for the user USR1, the display brightness of the virtual image IM seen by the user decreases gradually from the partial virtual image IMa to the partial virtual image IMe.

[0078] However, in the light source module 10 of the present embodiment, the angle of the prism structure of the optical film 100 will change according to the different areas where it is set on the substrate 101. Therefore, the light distribution after passing through the prism structures with different angles will also be different. For example, the light distribution of the light L1 after passing through the multiple prism structures 121 closer to the side edge 101e1 of the substrate 101 will be different relative to the forward light direction of the light source module 10 (for example Figure 2 direction Z) produces the largest right offset (such as Figure 4A ), the light L2 after passing through the plurality of prism structures 122 near the side edge 101e1 of the substrate 101 will produce the second largest rightward deviation relative to the forward light emitting direction of the light source module 10 (as shown in FIG. Figure 4B As shown), the light L3 after passing through the multiple prism structures 123 on the two side edges 101e1 and 101e2 farthest from the substrate 101 will be symmetrically distributed relative to the forward light emitting direction of the light source module 10 (as shown). Figure 4C shown).

[0079] It should be noted that, although not shown in the figure, the light distribution of the light L5 after passing through the multiple prism structures 125 closest to the side edge 101e2 of the substrate 101 will produce the largest left deviation relative to the forward light direction of the light source module 10, and its left deviation will be similar to Figure 4A The right offset shown, and the light distribution of the light L4 after passing through the multiple prism structures 124 near the side edge 101e2 of the substrate 101 will produce the second largest left offset relative to the forward light emitting direction of the light source module 10, and its left offset will be similar to Figure 4B The right offset shown.

[0080] In other words, the light distributions of the multiple light beams L1 to L5 after each passing through the optical film 100 are not the same. That is, the overall light field distribution of these light beams after passing through the optical film 100 of this embodiment is non-uniform. For example, the light intensity of the light beam L1 incident on the portion 200p1 of the projection screen 200, the light intensity of the light beam L2 incident on the portion 200p2 of the projection screen 200, the light intensity of the light beam L3 incident on the portion 200p3 of the projection screen 200, the light intensity of the light beam L4 incident on the portion 200p4 of the projection screen 200, and the light intensity of the light beam L5 incident on the portion 200p5 of the projection screen 200 may be different from each other.

[0081] Since the projection screen 200 is a curved surface, different portions (e.g., portions 200p1 to 200p5) along the direction X have different reflectivities for light incident in the same direction. By allowing the light rays L1 to L5 to enter the projection screen 200 with different light intensities, the light rays L1 to L5 can form multiple partial virtual images IMa to IMe at any eye point EP of the viewing area VA after being respectively reflected by the portions 200p1 to 200p5 of the projection screen 200, all of which have equal or comparable display brightness. Figure 5A That is, compared with the light source module 11 of the comparative example (such as Fig. 6A and Figure 6B As shown in FIG. 1 , the virtual image IM projected on the projection screen 200 by the optical module 10 of this embodiment may have a more uniform display brightness distribution.

[0082] It is worth mentioning that the geometric shapes of the multiple prism structures 120 of this embodiment are different, and they are symmetrically arranged with respect to the structural center axis SX on the substrate surface 101s (for example, the prism structure 121 and the prism structure 125 or the prism structure 122 and the prism structure 124). The technical effect produced can be compared with the comparative example (such as Figure 5B and Fig. 6A ) and this embodiment (as shown Figure 5A and Figure 1A In the light source module 11 of the comparative example, the geometric shapes of the multiple prism structures on the prism sheet 140 are symmetrical and identical to each other. This structural design makes the display brightness of the partial virtual image IMa much greater than the display brightness of the partial virtual image IMe. However, in the light source module 10 of the present embodiment, the geometric shapes of the optical film 100 are not identical, and are symmetrically arranged relative to the structural center axis SX on the substrate surface 101s. For example: the prism structure 121 with an asymmetric structural surface design can Figure 5A The display brightness of the partial virtual image IMa is compared with Figure 5B The display brightness of the partial virtual image IMa is greatly reduced, and the prism structure 125 which also has an asymmetric structure design and is symmetrically arranged with the prism structure 121 can make Figure 5A The display brightness of the partial virtual image IMe is compared with Figure 5B The display brightness of the partial virtual image IMe increased significantly and approached Figure 5A Similarly, the technical effect of similar display brightness of the partial virtual image IMb and the partial virtual image IMd can also be achieved by the prism structure 122 and the prism structure 124 which are symmetrically arranged with respect to the structural center axis SX and each has an asymmetric structural surface design, thereby improving the overall display uniformity of the partial virtual image IMa to the partial virtual image IMe, solving the problem of poor display uniformity of the existing virtual images.

[0083] Another thing to mention is that Figure 1A As shown, in this embodiment, the sum of the angles A1 and A2 of each prism structure 120 of the optical film 100 can be equal to each other. For example, the sum of the angle A1 and A2 of the prism structure 121 is equal to the sum of the angle A1 and A2 of the prism structure 122. Therefore, when manufacturing the manufacturing mold of the optical film 100, only one tool can be used and the tool angle can be rotated in sequence to complete the processing of the mold, which helps to simplify the process of the mold.

[0084] Please refer to Figure 3B ,exist Figure 2 In an optical film 100'' of another embodiment of the optical film 100, the substrate surface 101s'' of the substrate 101'' may be a curved surface that is concave in the reverse direction toward the direction Z. That is to say, the light field distribution after the light passes through the substrate 101'' is uneven. Therefore, it is more necessary to use the angle distribution design of the prism structure to allow the virtual image formed by any eye point EP in the viewing area VA after the light is reflected by different parts of the projection screen 200 to have a more uniform display brightness distribution.

[0085] Some other embodiments will be listed below to explain the present invention in detail, wherein the same components will be marked with the same symbols, and the description of the same technical content will be omitted. For the omitted parts, please refer to the aforementioned embodiments and will not be repeated below.

[0086] Fig. 8A and Figure 8B is a schematic cross-sectional view of a light source module according to a second embodiment of the present invention. 9A to 9C It's the light passing through Fig. 8A and Figure 8B The optical film has multiple prism structures in different areas and the light distribution after the light type bias film. Please refer to Figure 3A , Fig. 8A and Figure 8B , different from Figure 1A and Figure 1B The light source module 10A of this embodiment is replaced by a light type biasing film 170. Figure 1AThat is, the optical brightness enhancement film 160 is located on the side of the prism sheet 150 facing away from the optical film 100 and overlaps the optical film 100.

[0087] In the present embodiment, the optical bias film 170 includes a substrate 171 and a plurality of optical microstructures 173. These optical microstructures 173 may be arranged on a substrate surface 171s of the substrate 171 along a direction Y and extend along a direction X. The substrate 171 is provided with side edges 171e1 and side edges 171e2 on opposite sides along the direction Y, respectively. Each optical microstructure 173 has a structural surface ss3 and a structural surface ss4 facing the side edge 171e1 and the side edge 171e2 of the substrate 171, respectively. The structural surface ss3 of each optical microstructure 173 has the same angle A3 with the substrate surface 171s. The structural surface ss4 of each optical microstructure 173 has the same angle A4 with the substrate surface 171s, and the angle A3 is different from the angle A4. For example, in the present embodiment, the angle A3 may be greater than the angle A4, but is not limited thereto.

[0088] The light-biasing film 170 can further shift the light distribution along the direction Y. Fig. 9A , Fig. 9B and Fig. 9C Respectively Figure 4A , Figure 4B and Figure 4C By comparison, it can be seen that if the light further passes through the optical biasing film 170 of this embodiment, its light distribution will generally deviate along the direction Y. Figure 3A As shown, since the projection screen 200 is a complex surface (i.e., the curvature of the projection screen 200 along the direction X is different from the curvature along the direction Z), the light distribution of the light is offset along the direction Y by using the optical bias film 170 to further enhance the display of the virtual image (such as Figure 2 The brightness uniformity of the virtual image IM) shown in the direction Z.

[0089] Fig. 10A and Fig. 10B is a cross-sectional view of a light source module according to a third embodiment of the present invention. Fig. 10A and Fig. 10B The light source module 10B of this embodiment is replaced by another optical film 130. Figure 1A and Figure 1BThe optical film 130 is formed by the prism sheet 150 in the optical film 100. The structural design and function of the optical film 130 are similar to those of the optical film 100. More specifically, the light field distribution after the light passes through the optical film 130 is also non-uniform, and the effects of the optical film 130 and the optical film 100 on the light field distribution are in different spatial dimensions. For example, the effect of the optical film 100 on the light field distribution is in the direction X, while the effect of the optical film 130 on the light field distribution is in the direction Y.

[0090] In detail, the optical film 130 may include a substrate 131 and a plurality of prism structures 135. These prism structures 135 are arranged on a substrate surface 131s of the substrate 131 along a direction Y and extend along a direction X. That is, the arrangement direction of the prism structures 120 of the optical film 100 may be perpendicular to the arrangement direction of the prism structures 135 of the optical film 130. The substrate 131 is provided with side edges 131e1 and side edges 131e2 on opposite sides along the direction Y, respectively. Each prism structure 135 has a structural surface ss1″ and a structural surface ss2″ facing the side edge 131e1 and the side edge 131e2 of the substrate 131, respectively. An angle A1″ is formed between the structural surface ss1″ and the substrate surface 131s. An angle A2″ is formed between the structural surface ss2″ and the substrate surface 131s. In this embodiment, since the distribution of the angles A1 ″ and A2 ″ of each prism structure 135 of the optical film 130 is similar to that of the optical film 100 , the detailed description can be found in the relevant paragraphs of the aforementioned embodiment, which will not be repeated here.

[0091] In particular, when Figure 3A When the width of the projection screen 200 along the direction Z increases (for example, increases to twice the original width), different parts of the projection screen 200 along the direction Z will have different reflectivities for the light incident in the same direction. Therefore, by setting the optical film 130, the overall light field distribution of the light source module 10B in the direction Y can also be non-uniform. In this way, the display of virtual images (such as Figure 2 The brightness uniformity of the virtual image IM) shown in the direction Z.

[0092] Fig.11 is a schematic cross-sectional view of a light source module according to a fourth embodiment of the present invention. Fig.12 yes Fig.11 Schematic diagram of the configuration relationship between the optical film, projection screen and viewing area. Please refer to Fig.11 and Fig.12 The light source module 10C of this embodiment is Figure 1A The difference of the light source module 10 is that the position of the structural axis of the optical film on the substrate surface is different. Specifically, the structural axis SX" of this embodiment does not overlap the symmetry axis of the substrate 101 in the direction X. That is, the structural axis SX" is set away from the symmetry axis of the substrate 101.

[0093] For example, in this embodiment, the width of the viewing area VA" along the direction X is Figure 3A One third of the viewing area VA” and is only set for the user USR1. In other words, the vertical central axis VX2 of the viewing area VA” is not directly opposite to the vertical central axis VX1 of the projection screen 200 along the direction Y. The intersection line IL” of the virtual vertical plane VP formed by the vertical central axis VX1 and the vertical central axis VX2 and the substrate surface 101s intersects at the structural central axis SX”.

[0094] It is particularly noted that the midpoint CP of the intersection line IL" can define the position of the structural center axis SX" on the substrate surface 101s along the direction X. The multiple prism structures 120 of the optical film 100C are symmetrically arranged relative to the structural center axis SX". In other words, the position of the mirror center (i.e., the structural center axis) of the prism structure distribution of the optical film can be adjusted according to different application requirements (such as single or multiple use) to achieve optimization of the brightness uniformity of the displayed virtual image.

[0095] Fig.13 is a schematic cross-sectional view of an optical film according to a fifth embodiment of the present invention. Fig.14 yes Fig.13 A cross-sectional schematic diagram of another embodiment of an optical film. Fig.13 In this embodiment, a plurality of prism structures 121 and a plurality of prism structures 122 are provided on the substrate 101 of the optical film 100D. The prism structures are arranged on the substrate surface 101s of the substrate 101 along the direction X and extend along the direction Y. The angle A1a of the prism structure 121 is not equal to the angle A1b of the prism structure 122. The angle A2a of the prism structure 121 is not equal to the angle A2b of the prism structure 122.

[0096] Since the prism structure 121 and the prism structure 122 have different structural designs (i.e., the angles of the structural surfaces relative to the substrate surface 101s are different), it is necessary to change the tool when making prism structures with different angles. However, alignment tolerance is easily generated during the tool change process, resulting in partial overlap of the two prism structures with different angle designs, forming obvious bright lines on the film surface, or gaps between the two prism structures, forming obvious dark lines on the film surface.

[0097] In order to solve the above-mentioned problem, in the present embodiment, a plurality of prism structures 121″ and a plurality of prism structures 122″ may be further arranged between the prism structure 121 and the prism structure 122. The plurality of prism structures 121″ are arranged adjacent to the prism structure 121, and the plurality of prism structures 122″ are arranged adjacent to the prism structure 122. It is particularly noted that the prism structure 121″ and the prism structure 121 may be processed using the same tool, and the prism structure 122″ and the prism structure 122 may be processed using the same tool. Therefore, the angle A1a″ and the angle A2a″ of the prism structure 121″ may be respectively equal to the angle A1a and the angle A2a of the prism structure 121, and the angle A1b″ and the angle A2b″ of the prism structure 122″ may be respectively equal to the angle A1b and the angle A2b of the prism structure 122.

[0098] It is particularly noteworthy that the structural height H1” of the prism structure 121” is smaller than the structural height H1 of the prism structure 121, and the structural height H2” of the prism structure 122” is smaller than the structural height H2 of the prism structure 122. Since the structural dimensions of the prism structure 121” and the prism structure 122” are significantly smaller than the structural dimensions of the prism structure 121 and the prism structure 122, even if these prism structures 121” and these prism structures 122” partially overlap due to positioning tolerance during the tool changing process, the bright lines formed on the film surface appearance are not obvious. In other words, the setting area of ​​the prism structure 121” and the prism structure 122” can be used as a buffer area for the prism structure 121 and the prism structure 122 in the tool changing process of segmented processing, which helps to improve the process flexibility of the optical film 100D and the quality of the film surface appearance.

[0099] However, the present invention is not limited to this. In other embodiments, only a plurality of prism structures 121" or a plurality of prism structures 122" may be provided between the setting area of ​​the prism structure 121 and the setting area of ​​the prism structure 122. Even if a positioning error occurs during the tool changing process, so that part of the prism structure 121" overlaps part of the prism structure 122 or part of the prism structure 122" overlaps part of the prism structure 121, the bright lines formed on the appearance of the film surface will become less obvious due to the large difference in the structural dimensions of the overlapping prism structures. In this way, a technical effect similar to that of the present embodiment can be achieved.

[0100] In this embodiment, the plurality of prism structures 121" have a width W1a along the direction X, and the plurality of prism structures 122" have a width W1b along the direction X. Each prism structure 121 has a width W2a along the direction X, and each prism structure 122 has a width W2b along the direction X. Preferably, the ratio of the width W1a to the width W2a and the ratio of the width W1b to the width W2b are greater than or equal to 0.1 and less than 1.

[0101] It is particularly noted that the technical means disclosed in this embodiment can be applied to the splicing area of ​​any two prism structures in the aforementioned embodiments, for example: Figure 1A The splicing area between the prism structure 122 and the prism structure 123, the splicing area between the prism structure 123 and the prism structure 124, and / or the splicing area between the prism structure 124 and the prism structure 125 can achieve similar technical effects as those of the present embodiment.

[0102] Fig.13 The disclosed optical film 100D is an embodiment formed without any alignment error during the tool change process. If an alignment error occurs during the tool change process, the following will be produced: Fig.14 The optical film 100E shown. In the optical film 100E, the disposition area of ​​the plurality of prism structures 121" partially overlaps the disposition area of ​​the plurality of prism structures 122". That is, part of the prism structures 121" and part of the prism structures 122" are alternately arranged along the direction X.

[0103] Fig.15 is a cross-sectional view of an optical film according to a sixth embodiment of the present invention. Fig.15 , different from Fig.13 In the optical film 100D of the present embodiment, in the optical film 100F of the present embodiment, the structure height H1” of each of the plurality of prism structures 121A” decreases as they are away from the plurality of prism structures 121, and the structure height H2” of each of the plurality of prism structures 122A” decreases as they are away from the plurality of prism structures 122.

[0104] From another point of view, any two adjacent ones of the multiple prism structures 121A" are arranged at a pitch P1, and the pitch P1 decreases as they are away from the multiple prism structures 121. Any two adjacent ones of the multiple prism structures 122A" are arranged at a pitch P2, and the pitch P2 decreases as they are away from the multiple prism structures 122. The gradual design of the structural height and arrangement pitch of the aforementioned multiple prism structures 121A" (prism structure 122A") can effectively prevent the prism structure 121A" and the prism structure 122A" from having structural corner missing or poor forming due to poor fluidity of the photoresist during the yellow light imprinting process.

[0105] It should be noted that the gradual change in the height of the prism structure 121A" and the prism structure 122A" can be adjusted according to different process requirements or material selection, and the present invention is not limited thereto.

[0106] In summary, in an optical film of an embodiment of the present invention, the geometric shape or structural height of each prism structure may be different depending on its setting position on the substrate. The geometric shape distribution or structural height distribution of these prism structures can allow the light passing through each structural surface to be incident on different parts of the projection screen with different light intensities. The virtual image formed by any eye point in the viewing area after the light is reflected by different parts of the projection screen can have a more uniform display brightness distribution. In an optical film of an embodiment of the present invention, a third prism structure is provided between the first prism structure and the second prism structure having different angles. Since the angle of the third prism structure is the same as that of the first prism structure or the second prism structure and the structural height is lower than that of the first prism structure and the second prism structure, the setting area of ​​the third prism structure can be used as a buffer area for the first prism structure and the second prism structure during segmented processing, which helps to improve the process flexibility, and the optical film produced can have a good film surface appearance.

Claims

1. An optical film, suitable for use in a light source module and arranged corresponding to a projection screen, the projection screen having a viewing area consisting of a plurality of eye points, the optical film comprising: A first substrate having a first side edge and a second side edge respectively disposed on two opposite sides along a first direction; as well as A plurality of prism structures are arranged on a first substrate surface of the first substrate along the first direction and extend along a second direction, wherein the prism structures include a first prism structure and a second prism structure having different geometric shapes. A light source of the light source module is used to emit a first light and a second light. The first light is incident on a first part of the projection screen with a first light intensity after passing through the first prism structure. The second light is incident on a second part of the projection screen with a second light intensity after passing through the second prism structure. The first light intensity is not equal to the second light intensity. A portion of a virtual image formed by the first light with the first light intensity at any one of the eye points after being reflected by the first part of the projection screen has a first display brightness. Another portion of a virtual image formed by the second light with the second light intensity at any one of the eye points after being reflected by the second part of the projection screen has a second display brightness. The first display brightness is equal to the second display brightness.

2. The optical film according to claim 1, wherein: Each of the prism structures has a first structural surface and a second structural surface facing the first side edge and the second side edge respectively. There is a first angle between the first structural surface and the first substrate surface. The first angle of the first prism structure is different from the first angle of the second prism structure.

3. The optical film as claimed in claim 2, wherein a second angle is formed between the second structure surface and the first substrate surface, and the sum of the first angle and the second angle of the first prism structure is equal to the sum of the first angle and the second angle of the second prism structure.

4. The optical film as described in claim 2, wherein the projection screen also has a first vertical central axis, the viewing area has a second vertical central axis, the first vertical central axis and the second vertical central axis constitute a virtual vertical plane, an intersection line of the virtual vertical plane and the first substrate surface has a midpoint, the first substrate surface is provided with a structural central axis, the structural central axis passes through the midpoint and extends in the second direction, and the prism structures are symmetrically arranged relative to the structural central axis.

5. The optical film as described in claim 4, wherein a second angle is formed between the second structure surface and the first substrate surface, the first angle of each of the prism structures decreases from the first side edge to the second side edge, and the second angle of each of the prism structures decreases from the second side edge to the first side edge. 6 . The optical film as claimed in claim 5 , wherein each of the prism structures has a structure height relative to the surface of the first substrate, and the structure height of each of the prism structures decreases along the structure center axis toward the first side edge or the second side edge. The optical film as claimed in claim 4 , wherein the structural center axis overlaps the intersection line. The optical film as claimed in claim 4 , wherein the structural center axis intersects the intersection line.

9. The optical film as described in claim 1, wherein the light source module also includes a light-type biasing film arranged overlapping the optical film, the light-type biasing film includes a second substrate and a plurality of optical microstructures, the optical microstructures are arranged on a second substrate surface of the second substrate along the second direction and extend along the first direction, the second substrate is provided with a third side edge and a fourth side edge on opposite sides along the second direction, each of the optical microstructures has a third structural surface and a fourth structural surface facing the third side edge and the fourth side edge respectively, the third structural surface of each of the optical microstructures has a same third angle with the second substrate surface, the fourth structural surface of each of the optical microstructures has a same fourth angle with the second substrate surface, and the third angle is different from the fourth angle.

10. An optical film, comprising: a first substrate; as well as A plurality of prism structures are arranged on a first substrate surface of the first substrate along a first direction and extend along a second direction, wherein the first substrate is provided with a first side edge and a second side edge on opposite sides along the first direction, respectively, and each of the prism structures has a structural height relative to the first substrate surface, and the structural height of each of the prism structures first increases and then decreases from the first side edge to the second side edge.

11. An optical film as described in claim 10, wherein each of the prism structures has a first structural surface and a second structural surface facing the first side edge and the second side edge respectively, a first angle between the first structural surface of each of the prism structures and the first substrate surface decreases from the first side edge to the second side edge, and a second angle between the second structural surface of each of the prism structures and the first substrate surface decreases from the second side edge to the first side edge.

12. The optical film as described in claim 10 is suitable for use in a light source module and is arranged corresponding to a projection screen, wherein the prism structures include a first prism structure and a second prism structure, a light source of the light source module is used to emit a first light and a second light, the first light is incident on a first part of the projection screen with a first light intensity after passing through the first prism structure, and the second light is incident on a second part of the projection screen with a second light intensity after passing through the second prism structure, the first light intensity is not equal to the second light intensity, a part of the virtual image formed by the first light with the first light intensity after being reflected by the first part of the projection screen in a viewing area of ​​the projection screen has a first display brightness, and another part of the virtual image formed by the second light with the second light intensity after being reflected by the second part of the projection screen in the viewing area of ​​the projection screen has a second display brightness, and the first display brightness is equal to the second display brightness.

13. An optical film as described in claim 12, wherein the projection screen has a first vertical central axis, the viewing area has a second vertical central axis, the first vertical central axis and the second vertical central axis form a virtual vertical plane, an intersection line of the virtual vertical plane and the first substrate surface has a midpoint, the first substrate surface is provided with a structural central axis, the structural central axis passes through the midpoint and extends in the second direction, and the prism structures are symmetrically arranged relative to the structural central axis. The optical film as claimed in claim 13 , wherein the structural center axis overlaps the intersection line. The optical film as claimed in claim 13 , wherein the structural center axis intersects the intersection line.

16. An optical film as described in claim 12, wherein the light source module also includes a light-type biasing film arranged overlapping the optical film, the light-type biasing film includes a second substrate and a plurality of optical microstructures, the optical microstructures are arranged on a second substrate surface of the second substrate along the second direction and extend along the first direction, the second substrate is provided with a third side edge and a fourth side edge on opposite sides along the second direction, each of the optical microstructures has a third structural surface and a fourth structural surface facing the third side edge and the fourth side edge respectively, the third structural surface of each of the optical microstructures has a same third angle with the second substrate surface, the fourth structural surface of each of the optical microstructures has a same fourth angle with the second substrate surface, and the third angle is different from the fourth angle.

17. An optical film, comprising: A substrate having a first side edge and a second side edge respectively disposed on two opposite sides along a first direction; as well as A plurality of prism structures are arranged on a substrate surface of the substrate along the first direction and extend along a second direction, each of the prism structures has a structure height relative to the substrate surface, each of the prism structures has a first structure surface and a second structure surface facing the first side edge and the second side edge respectively, a first angle is formed between the first structure surface and the substrate surface, and a second angle is formed between the second structure surface and the substrate surface, the prism structures include a plurality of first prism structures, a plurality of second prism structures and a plurality of third prism structures, at least a portion of the third prism structures is disposed between each of the first prism structures and each of the second prism structures, The first angle of each of the third prism structures is equal to the first angle of each of the first prism structures, and is not equal to the first angle of each of the second prism structures; the second angle of each of the third prism structures is equal to the second angle of each of the first prism structures, and is not equal to the second angle of each of the second prism structures; and the structural height of each of the third prism structures is less than the structural height of each of the first prism structures and the second prism structures.

18. An optical film as described in claim 17, wherein the prism structures also include a plurality of fourth prism structures, which are arranged between at least a portion of the third prism structures and each of the second prism structures, the first angle of each of the fourth prism structures is equal to the first angle of each of the second prism structures, and is not equal to the first angle of each of the first prism structures, the second angle of each of the fourth prism structures is equal to the second angle of each of the second prism structures, and is not equal to the second angle of each of the first prism structures, and the structural height of each of the fourth prism structures is less than the structural height of each of the first prism structures and the second prism structures. 19 . The optical film as claimed in claim 18 , wherein the structure height of each of the third prism structures decreases as it moves away from the first prism structures, and the structure height of each of the fourth prism structures decreases as it moves away from the second prism structures.

20. The optical film as claimed in claim 19, wherein any two adjacent ones of the third prism structures are arranged at a first pitch, and the first pitch decreases as they are away from the first prism structures, and any two adjacent ones of the fourth prism structures are arranged at a second pitch, and the second pitch decreases as they are away from the second prism structures. 21 . The optical film as claimed in claim 17 , wherein the third prism structures have a first width along the first direction, each of the first prism structures has a second width along the first direction, and a ratio of the first width to the second width is greater than or equal to 0.1 and less than or equal to 1.

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