OPTICAL LAYER

Abstract

An optical layer (100) is provided, containing a first substrate (101) and a plurality of prism structures (120). The plurality of prism structures (120) is arranged on a first substrate surface (101s) of the first substrate (101) along a first direction (X) and extends along a second direction (Y). The first substrate (101) has a first side edge (101e1) and a second side edge (101e2) on opposite sides of it along the first direction (X). Each of the prism structures (120) has a structural height (H) relative to the first substrate surface (101s), and the structural height (H) of each prism structure (120) increases first and then decreases from the first side edge (101e1) to the second side edge (101e2).

Description

BACKGROUND Technical area

[0001] The disclosure relates to an optical film or optical layer, in particular an optical layer provided with prism structures. Description of the state of the art

[0002] Advances in display technology have driven the development of display applications in vehicles. Among these, head-up displays (HUDs), which utilize the vehicle's windshield as a projection screen, have become a major focus for manufacturers. Generally, the light source module used in a HUD is typically equipped with a prism layer for light focusing and a brightness enhancer layer to improve optical energy utilization, and it provides a degree of uniformity in light output.However, since most vehicle windshields are freeform surfaces and often feature special reflective coatings, these coatings further alter the windshield's reflective properties, leading to varying degrees of reflectance under different lighting conditions (such as different polarization states or angles of incidence). Consequently, despite the uniformity of the light emitted by the light source module, the brightness uniformity of the virtual image formed by reflection on the windshield may be reduced. SUMMARY

[0003] The revelation provides an optical layer that can effectively improve the brightness uniformity of an image formed by light reflected from a projection screen.

[0004] The revelation provides an optical layer that offers greater process flexibility and a more uniform appearance of the layer surface.

[0005] An optical layer of the disclosure is adapted for use in a light source module and configured according to a projection screen. The projection screen has a viewing area formed by a multitude of viewpoints. The optical layer contains a first substrate and a multitude of prism structures. The first substrate has a first side edge and a second side edge on opposite sides along a first direction. A multitude of prism structures is arranged on a first substrate surface of the first substrate along the first direction and extends along a second direction. The multitude of prism structures includes a first prism structure and a second prism structure with distinct geometric shapes. A light source of the light source module is configured to emit a first light beam and a second light beam.The first light ray, after passing through the first prism structure, strikes a first section of the projection screen with a first light intensity. The second light ray, after passing through the second prism structure, strikes a second section of the projection screen with a second light intensity. The first light intensity is not equal to the second light intensity. A section of the virtual image, formed at any of the multiple viewpoints by the first light ray with the first light intensity and reflected from the first section of the projection screen, has a first display brightness. Another section of the virtual image, formed at any of the multiple viewpoints by the second light ray with the second light intensity and reflected from the second section of the projection screen, has a second display brightness. The first display brightness is equal to the second display brightness.

[0006] An optical layer of the revelation contains a first substrate and a plurality of prism structures. The plurality of prism structures is arranged on a first substrate surface of the first substrate along a first direction and extends along a second direction. The first substrate has a first lateral edge and a second lateral edge on opposite sides of it along the first direction. Each of the plurality of prism structures has a structural height relative to the first substrate surface. The structural height of each of the plurality of prism structures increases first and then decreases from the first lateral edge to the second lateral edge.

[0007] An optical layer of the disclosure contains a substrate and a plurality of prism structures. The substrate has a first side edge and a second side edge on opposite sides of it along a first direction. The plurality of prism structures is arranged on a substrate surface along the first direction and extends along a second direction. Each of the plurality of prism structures has a structural height relative to the substrate surface and a first structural surface and a second structural surface, respectively, facing the first and second side edges. A first angle is contained between the first structure surface and the substrate surface. A second angle is contained between the second structure surface and the substrate surface.The plurality of prism structures contains a plurality of first prism structures, a plurality of second prism structures, and a plurality of third prism structures. At least one segment of the plurality of third prism structures is positioned between each plurality of first prism structures and each plurality of second prism structures. The first angle of each plurality of third prism structures is equal to the first angle of each plurality of first prism structures and differs from the first angle of each plurality of second prism structures. The second angle of each plurality of third prism structures is equal to the second angle of each plurality of first prism structures and differs from the second angle of each plurality of second prism structures.The structural height of each of the plurality of third prism structures 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 foregoing, in the optical layer of one embodiment of the disclosure, the geometric shape or structural height of each prism structure varies according to its position on the substrate. The geometric shape distribution or structural height distribution of these prism structures allows light passing through the respective structure surfaces to strike different sections of the projection screen with varying light intensities. After being reflected from different sections of the projection screen, the virtual image formed at each eye point within the viewing area can exhibit a more uniform display brightness distribution. In the optical layer of one embodiment of the disclosure, a third prism structure is provided between the first and second prism structures, with different angles.Since the angle of the third prism structure corresponds to that of the first or second prism structure, and the structure height of the third prism structure is less than that of the first and second prism structures, the region where the third prism structure is provided can serve as a buffer area for the segmented processing of the first and second prism structures. This contributes to improved process flexibility, and the fabricated optical layer can exhibit a desired surface appearance.

[0009] To make the above clearer, several embodiments are described in detail below with reference to drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The accompanying drawings are included to provide a further understanding of the revelation and are incorporated into and form part of this description. The drawings illustrate exemplary embodiments of the revelation and, together with the description, serve to explain the fundamentals of the revelation. Fig. 1A and Fig. Figure 1B shows schematic cross-sectional views of a light source module according to a first embodiment of the disclosure. Fig. Figure 2 is a schematic top view showing the configuration relationship between the optical layer and the projection screen. Fig. 1 illustrates. Fig. 3A is a schematic diagram showing the configuration relationship between the optical layer, the projection screen, and the viewing area in Fig. 2 illustrated. Fig. 3B is a schematic diagram illustrating the configuration relationship between another embodiment of the optical layer in Fig. 2, the projection screen and the viewing area are illustrated. Fig. 4A to Fig. Figure 4C illustrates the light distributions of the light beam after passing through different prism structures in different regions of the optical layer in Fig. 1. Fig. 5A is a display brightness distribution of a virtual image formed at an eye point in the viewing area after light passes through the optical layer of Fig. 1 passed through and was reflected by the projection screen. Fig. Figure 5B shows the brightness distribution of a virtual image formed at an eye point in the viewing area after light has passed through an optical layer of a comparison example and is reflected from the projection screen. Fig. 6A and Fig. Figure 6B shows schematic cross-sectional views of an optical module from a comparative example. Fig. Figure 7 is a schematic cross-sectional view of another embodiment of the optical layer in Fig. 1A. Fig. 8A and Fig. Figure 8B are schematic cross-sectional views of a light source module according to a second embodiment of the disclosure. Fig. 9A to Fig. Figure 9C illustrates the light distribution of the light beam after passing through the multitude of prism structures in different regions of the optical layer in Fig. 8A and Fig. 8B and the pattern shift layer. Fig. 10A and Fig. Figure 10B are schematic cross-sectional views of a light source module according to a third embodiment of the disclosure. Fig. Figure 11 is a schematic cross-sectional view of a light source module according to a fourth embodiment of the disclosure. Fig. Figure 12 is a schematic diagram illustrating the configuration relationship between the optical layer, the projection screen, and the viewing area. Fig. 11 illustrated. Fig. Figure 13 is a schematic cross-sectional view of an optical layer according to a fifth embodiment of the disclosure. Fig. Figure 14 is a schematic cross-sectional view of another embodiment of the optical layer in Fig. 13. Fig. Figure 15 is a schematic cross-sectional view of an optical layer according to a sixth embodiment of the disclosure. DESCRIPTION OF THE EXECUTION FORMS

[0011] As used here, the terms "approximately," "about," "essentially," or "basically" include the stated values ​​as well as average values ​​within an acceptable range of deviation, as determined by a person skilled in the art, taking into account specific measured quantities and the errors associated with the measurement (i.e., the limitations of the measuring system). For example, "about" may refer to within one or more standard deviations from the standard value, or to within ±30%, ±20%, ±15%, ±10%, or ±5%. Furthermore, depending on the nature of the measurement, the cutting process, or other relevant characteristics, the terms "approximately," "about," "essentially," or "basically" may be interpreted with a selectively acceptable range of deviation or standard deviation, whereby a single standard deviation does not necessarily apply to all characteristics.

[0012] In the drawings, the thicknesses of planes, layers, plates, and regions are exaggerated for clarity. It is understood that when components such as planes, layers, regions, or substrates are described as "on" or "connected to" another component, they may lie directly on top of or be connected to that other component, or intermediate components may be present. Conversely, no intermediate components are present when components are described as "directly on" or "directly connected to" another component. As used here, "connected" can refer to a physical and / or electrical connection. Furthermore, "electrically connected" can still allow for the presence of other components between the two elements.

[0013] Furthermore, relative terms such as "lower" or "bottom" and "upper" or "top" can be used here to describe the relationship between components, as shown in the figures. It should be understood that such relative terms serve to capture different orientations of the device beyond those shown in the drawings. For example, if a device is rotated in a drawing, the component described as "below" another component may now be positioned "above" it. Therefore, exemplary terms such as "below" can include both the "below" and "above" orientations, depending on the specific orientation in the figures. Similarly, a component described as "below" or "below" another may also be positioned "above" or "above" it if the figure is rotated.Therefore, exemplary terms such as "above" or "below" can contain both orientations.

[0014] The exemplary embodiments described here refer to schematic cross-sectional views, which are idealized examples. Deviations in the depicted shapes, for example due to manufacturing techniques and / or tolerances, are to be expected. Therefore, the embodiments described here should not be interpreted as being limited to the specific shapes shown, but should also include shape deviations resulting from manufacturing. For example, regions depicted or described as flat may have rough and / or nonlinear properties. Furthermore, sharp corners shown in the drawings may actually be rounded. Therefore, the regions shown in the figures are essentially schematic and are not intended to represent exact shapes or to limit the scope of the claimed invention.

[0015] Exemplary embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. Where possible, the same reference numerals are used in the drawings and the description to refer to identical or similar parts.

[0016] Fig. 1A and Fig. Figure 1B shows schematic cross-sectional views of a light source module according to a first embodiment of the disclosure. Fig. Figure 2 is a schematic top view showing the configuration relationship between the optical layer and the projection screen. Fig. 1 illustrates. Fig. 3A is a schematic diagram showing the configuration relationship between the optical layer, the projection screen, and the viewing area in Fig. 2 illustrated. Fig. 3B is a schematic diagram showing the configuration between another embodiment of the optical layer in Fig. 2, the projection screen and the viewing area are illustrated. Fig. 4A to Fig. 4C illustrates light distributions of the light beam after passing through different prism structures in different regions of the optical layer in Fig. 1. Fig. Figure 5A shows a display brightness distribution of a virtual image formed at an eye point in the viewing area after the light passes through the optical layer. Fig. 1 has passed through and is reflected by the projection screen. Fig. Figure 5B shows the display brightness distribution of a virtual image formed at an eye point in the viewing area after the light has passed through an optical layer from a comparison example and is reflected from the projection screen. Fig. 6A and Fig. Figure 6B shows schematic cross-sectional views of an optical module from a comparative example. Fig. Figure 7 is a schematic cross-sectional view of another embodiment of the optical layer in Fig. 1A. For clarity, the light source module 10 is shown in Fig. 2 only the optical layer 100 from Fig. 1A.

[0017] With reference to Fig. 1A and Fig. 1B comprises an optical layer 100, a substrate 101, and a plurality of prism structures 120. The plurality of prism structures 120 are arranged, for example, on a substrate surface 101s of the substrate 101 along a direction X and extend along a direction Y, wherein the direction X and the direction Y may optionally be perpendicular to each other, although the disclosure is not limited to this. The substrate 101 is provided with a side edge 101e1 and a side edge 101e2 on opposite sides thereof along the direction X. Each of the prism structures 120 has a first structure surface ss1 and a second structure surface ss2, respectively facing the side edge 101e1 and the side edge 101e2. A first angle A1 is contained between the first structure surface ss1 and the substrate surface 101s. A second angle A2 is contained between the second structure surface ss2 and the substrate surface 101s.

[0018] It is particularly noteworthy that the structural surfaces of the prism structures 120 of the optical layer 100 can form different angles relative to the substrate surface 101s. For example, in the embodiment, the substrate 101 is successively provided with a prism structure 121, a prism structure 122, a prism structure 123, a prism structure 124, and a prism structure 125 from side edge 101e1 to side edge 101e2. These prism structures are arranged symmetrically relative to a structural axis SX on the substrate surface 101s, and the structural axis SX is parallel to the Y direction. It should be noted that the structural axis SX of the embodiment is also an axis of symmetry of the substrate 101 in the X direction, but the disclosure is not limited to this.

[0019] The first angle A1 of each of the prism structures 121 to 125 decreases from side edge 101e1 to side edge 101e2, and the second angle A2 decreases from side edge 101e2 to side edge 101e1. For example, the first angle A1 of prism structure 122, which is farther from side edge 101e1, is smaller than the first angle A1 of prism structure 121, which is closer to side edge 101e1. The second angle A2 of prism structure 121, which is farther from side edge 101e2, is smaller than the second angle A2 of prism structure 122, which is closer to side edge 101e2.

[0020] From another perspective, the structure height H of each of the prism structures relative to the substrate surface 101s initially increases and then decreases from side edge 101e1 to side edge 101e2 of the substrate 101. In other words, the structure height H of each of the prism structures decreases from the structure axis SX towards either side edge 101e1 or side edge 101e2 of the substrate 101. In this way, the prism structures can be arranged at equal intervals on the substrate surface 101s, thus avoiding the occurrence of moiré patterns when the optical layer 100 is stacked with other layers, which would otherwise impair the visual effect.

[0021] However, the revelation is not limited to this. As in Fig. As shown in Figure 7, in a further modified embodiment, the first angle A1 of each prism structure 120A of the optical layer 100A increases from the structure axis SX towards the side edge 101e1 of the substrate 101, and the second angle A2 of each prism structure 120A increases from the structure axis SX towards the side edge 101e2 of the substrate 101. Conversely, the structure axis H of each prism structure 120A increases from the structure axis SX towards either the side edge 101e1 or the side edge 101e2 of the substrate 101.

[0022] First, it should be noted that the light field distribution through the optical layer 100 (or the optical layer 100A in Fig. 7) the light passing through the embodiment is anisotropic. For example, in this embodiment, the plurality of prism structures 121 to 125 with five different angular configurations can generate different light field distributions after the light has passed through different regions of the optical layer 100. Here, for example, the different regions are each provided with the plurality of prism structures 121 to 125, and each region is provided with a plurality of prism structures with the same angular configuration. However, the disclosure is not limited to this. In other embodiments, the number of angular types of the prism structures of the optical layer can be adapted according to the actual application requirements (for example, the number of subdivided regions).

[0023] With reference to the Fig. In Figures 1A to 3A, the optical layer 100 is designed for use in a light source module 10 and configured accordingly for a projection screen 200. In this embodiment, the projection screen 200 is, for example, a windshield or a side window of a vehicle, and the light source module 10 used in combination with the projection screen 200 can form a head-up display (HUD) for use in vehicles, but the disclosure is not limited thereto. In other embodiments, the projection screen 200 can be a panoramic window of a building.

[0024] For example, the light source module 10 can further comprise a light source 50, a diffusion layer 60, a prism layer 150, and an optical brightness enhancement layer 160. The light source 50 is designed to emit a plurality of light rays, such as light rays L1 to L5. The light source 50 can, for example, be a light panel provided with a plurality of light-emitting elements (e.g., LEDs) arranged in an array, but the disclosure is not limited thereto. The optical layer 100 is arranged on one side of a light-emitting surface of the light source 50 and is located on the transmission path of the light rays. The diffusion layer 60 can optionally be arranged between the optical layer 100 and the light source 50.The optical brightness enhancer layer 160 is arranged on one side of the optical layer 100 facing away from the light source 50. The prism layer 150 is arranged between the optical layer 100 and the optical brightness enhancer layer 160. The optical brightness enhancer layer 160 can, for example, be a dual brightness enhancer (DBEF) layer manufactured by 3M, but the disclosure is not limited to this. Additionally, a cavity structure disclosed in US8,390,760 can also be arranged between the diffusion layer 60 and the light source 50.

[0025] The prism layer 150 can contain a substrate 151 and a plurality of prism structures 153. In this embodiment, the prism structures 153 can be arranged on the substrate 151 along the Y direction and extend along the X direction. That is, the arrangement direction of the prism structures 153 of the prism layer 150 can be perpendicular to the arrangement direction of the prism structures 120 of the optical layer 100. It should be noted that, unlike the optical layer 100, the two structural faces of each prism structure 153 of the prism layer 150 are arranged symmetrically and configured to improve the light convergence of the light source module 10 along the Y direction.

[0026] For example, the light source module 10 can be arranged on a platform between the dashboard and the windshield of a vehicle and project several light beams L1 to L5 towards the projection screen 200. These light beams L1 to L5, after being reflected by the projection screen 200, are transmitted into a viewing area VA, which is composed of several eye points EP. The light beams L1 to L5 are received by a user USR1 (for example, a driver) or a user USR2 (for example, a front-seat passenger) at any eye point EP in the viewing area VA, and a virtual image IM is formed behind the projection screen 200, as shown in Fig. 2 shown.

[0027] In this embodiment, the viewing area VA has a width along direction X that can simultaneously cover both users USR1 and USR2, but the disclosure is not limited thereto. The projection screen 200 and the viewing area VA each have an upright axis VX1 and an upright axis VX2, and the upright axis VX2 of the viewing area VA is oriented along direction Y toward the upright axis VX1 of the projection screen 200. The upright axes VX1 and VX2 can define a virtual plane VP. The virtual plane VP intersects the substrate surface 101s at a section line IL, with a midpoint CP. The structural axis SX passes through the midpoint CP of the section line IL and extends along direction Y. More precisely, in this embodiment, the structural axis SX overlaps (or coincides with) the section line IL, but the disclosure is not limited thereto.

[0028] In this embodiment, the projection screen 200 can contain a plurality of sections 200p1 to 200p5. The multiple light rays L1 to L5 emitted by the light source 50 are each projected onto the plurality of sections 200p1 to 200p5 of the projection screen 200 after passing through the plurality of prism structures 121 to 125 of the optical layer 100. After being reflected by the plurality of sections 200p1 to 200p5 of the projection screen 200, these light rays L1 to L5 form multiple virtual partial images IMa to IMe, which constitute the aforementioned virtual image IM at any arbitrary eye point EP in the viewing area VA.

[0029] First, it should be noted that, since the projection screen 200 is a curved surface, different sections of it (for example, sections 200p1 to 200p5) arranged along direction X may have different reflectances for light rays incident from the same direction. Therefore, light rays with a uniform light field distribution may exhibit a non-uniform light field distribution after reflection by the projection screen 200. For example, in a light source module 11 (as in the Fig. 6A and Fig. Figure 6B shows a different prism layer 140 used in a comparative example to replace the optical layer 100 in the light source module 10 of the embodiment. Similar to prism layer 150, prism layer 140 can contain a substrate 141 and a plurality of prism structures 143. In the comparative example, the prism structures 143 can be arranged on the substrate 141 along direction X and extend along direction Y. That is, the arrangement direction of the prism structures 143 of prism layer 140 can be perpendicular to the arrangement direction of the prism structures 153 of prism layer 150. The two structural faces of each prism structure 143 of prism layer 140 are arranged symmetrically and configured to improve the light convergence of the light source module 11 along direction X.

[0030] Due to the stacked arrangement of prism position 140 and prism position 150, the light rays emitted by the light source module 11 of the comparison example exhibit better light convergence and a more uniform light field distribution in both the X and Y directions. After reflection by the in Fig. On the projection screen 200 shown, the uniform light field distribution can become uneven at any eye point EP. The display brightness of a multitude of virtual sub-images of the virtual image IM, which is formed by the light rays with uneven light field distribution at any eye point EP in the viewing area VA, can differ considerably. As shown in Fig. 2 and Fig. As shown in Figure 5B, the display brightness of the virtual image IM decreases for the user USR1 from the virtual sub-image IMa to the virtual sub-image IMe.

[0031] In the light source module 10 of the embodiment, however, the angles of the prism structures of the optical layer 100 vary depending on their arrangement regions on the substrate 101. Therefore, the light distribution of the light rays also differs after passing through prism structures with different angles. For example, after passing through the prism structures 121 that are closer to the side edge 101e1 of the substrate 101, the light ray L1 exhibits the greatest shift to the right relative to the forward light emission direction (for example, direction Z in the Fig. 2) of the light source module 10 (as in Fig. 4A). After passing through the prism structures 122, which are located somewhat further from the side edge 101e1, the light beam L2 exhibits the second largest shift to the right relative to the forward light emission direction of the light source module 10 (as shown in Fig. 4B), and the light beam L3, after passing through the prism structures 123, which are furthest from both side edges 101e1 and 101e2 of the substrate 101, exhibits a symmetrical distribution relative to the forward light emission direction of the light source module 10 (as shown in Fig. 4C shown).

[0032] It should be noted that, although not shown, the light distribution of the light beam L5 after passing through the multitude of prism structures 125 that are closest to the side edge 101e2 of the substrate 101 exhibits the greatest shift to the left relative to the forward light emission direction of the light source module 10, and the magnitude of the shift to the left is similar to the magnitude of the shift to the right that is shown in Fig. 4A is shown. After passing through the plurality of prism structures 124, which are second closest to the side edge 101e2 of the substrate 101, the light distribution of the light beam L4 exhibits the second largest shift to the left relative to the forward light emission direction of the light source module 10, and the magnitude of the shift to the left is similar to the magnitude of the shift to the right shown in Fig. 4B is shown.

[0033] In other words, the light distributions of the several light rays L1 to L5 differ from one another after passing through the optical layer 100. That is, the entire light field distribution of the light rays after passing through the optical layer 100 of the embodiment is anisotropic. For example, the light intensity of light ray L1 entering section 200p1 of the projection screen 200, the light intensity of light ray L2 entering section 200p2 of the projection screen 200, the light intensity of light ray L3 entering section 200p3 of the projection screen 200, the light intensity of light ray L4 entering section 200p4 of the projection screen 200, and the light intensity of light ray L5 entering section 200p5 of the projection screen 200 differ from one another.

[0034] Since the projection screen 200 is a curved surface, its various sections (for example, the plurality of sections 200p1 to 200p5), arranged along direction X, can exhibit different reflectances for light rays incident from the same direction. By allowing light rays L1 to L5 to enter the projection screen 200 with different light intensities, the plurality of virtual sub-images IMa to IMe, each formed by the light rays L1 to L5 after being reflected by the plurality of sections 200p1 to 200p5 of the projection screen 200, can have the same or substantially the same display brightness at each eye point EP in the viewing area VA, as shown in Fig. 5A shown. That is, in comparison to the light source module 11 of the comparison example (as shown in the Fig. 6A and Fig. (as shown in Figure 6B) the virtual image IM projected onto the projection screen 200, which uses the optical module 10 of the embodiment, can have a more uniform display brightness distribution.

[0035] It is worth noting that the respective geometries of the plurality of prism structures 120 of the embodiment are not identical and are arranged symmetrically relative to the structure axis SX on the substrate surface 101s (for example, prism structure 121 and prism structure 125 or prism structure 122 and prism structure 124). The effectiveness of this configuration can be demonstrated by comparing it to the comparative example (as shown in the Fig. 5B and Fig. 6A) with the embodiment (as shown in the Fig. 5A and Fig. (1A shown). In the light source module 11 of the comparative example, the multitude of prism structures on the prism layer 140 all exhibit symmetrical and identical geometries. This structural design results in the display brightness of the virtual sub-image IMa being significantly greater than the display brightness of the virtual sub-image IMe. In the light source module 10 of the embodiment, however, the respective geometries of the prism structures on the optical layer 100 are not identical and are not arranged symmetrically relative to the structural axis SX on the substrate surface 101s. For example, the prism structure 121 with an asymmetrical structural surface design can significantly increase the display brightness of the virtual sub-image IMa. Fig. 5A compared to the one in Fig. 5B significantly reduces, while the prism structure 125, which is arranged symmetrically to the prism structure 121 and also has an asymmetric structural design, reduces the display brightness of the virtual sub-image IMe in Fig. 5A compared to the one in Fig. 5B can be significantly increased, bringing it close to the display brightness of the virtual sub-image IMa in Fig. 5A. Similarly, the technical effect of making the display brightness of the virtual sub-images IMb and IMd approximately equal can be achieved by the symmetrically arranged prism structures 122 and 124 with asymmetric structural surface designs with respect to the structure axis SX, thereby improving the overall display uniformity of the virtual sub-images IMa to IMe and solving the problem of poor display uniformity in conventional virtual images.

[0036] Furthermore, as in Fig. As shown in Figure 1A, in this embodiment the sum of the first angle A1 and the second angle A2 of each prism structure 120 of the optical layer 100 is equal. For example, the sum of the angles A1 and A2 of prism structure 121 is equal to the sum of the angles A1 and A2 of prism structure 122. Therefore, it is possible to use only one cutting tool when manufacturing the mold for producing the optical layer 100, and the mold can be completed by sequentially rotating the tool angle, which simplifies the mold manufacturing process.

[0037] With reference to Fig. 3B can be implemented in an optical layer 100" according to a further embodiment of the in Fig. In the optical layer 100 shown in Figure 2, the substrate surface 101s" of the substrate 101" is a curved surface that is recessed in a direction opposite to direction Z. In other words, the light field distribution of the light beam after passing through the substrate 101" is uneven. Therefore, it is all the more necessary to use the angular distribution design of the prism structures to ensure that the virtual image formed at any eye point EP in the viewing area VA by the light rays reflected from different sections of the projection screen 200 has a more uniform brightness distribution.

[0038] Several other embodiments of the disclosure are described in detail below. Identical components are identified by the same reference numerals, and repeated technical descriptions are omitted. For the omitted sections, reference is made to the aforementioned embodiment, which is not described redundantly here.

[0039] Fig. 8A and Fig. Figure 8B are schematic cross-sectional views of a light source module according to a second embodiment of the disclosure. Fig. 9A to Fig. Figure 9C illustrates the light distribution of the light beam after passing through the multitude of prism structures in different regions of the optical layer in Fig. 8A and Fig. 8B and the pattern-shifting layer. With reference to Fig. 3A, Fig. 8A and Fig. 8B uses a light source module 10A of the embodiment in contrast to the light source module 10 in Fig. 1A and Fig. 1B instead of the one in Fig. Figure 1A shows an optical brightness enhancement layer 160 and a light pattern shifting layer 170. That is, the light pattern shifting layer 170 is arranged on the side of the prism layer 150 that is facing away from the optical layer 100 and overlaps the optical layer 100.

[0040] In this embodiment, the light pattern shift layer 170 comprises a substrate 171 and a plurality of optical microstructures 173. These optical microstructures 173 are arranged on a substrate surface 171s of the substrate 171 along the Y direction and extend along the X direction. The substrate 171 is provided with a side edge 171e1 and a side edge 171e2 on opposite sides along the Y direction. Each of the optical microstructures 173 has a structure surface ss3 facing the side edge 171e1 of the substrate 171 and a structure surface ss4 facing the side edge 171e2. An angle A3 between the structure surface ss3 of each optical microstructure 173 and the substrate surface 171s is equal to 1. An angle A4, which is contained between the structure surface ss4 of each optical microstructure 173 and the substrate surface 171s, is equal.Angle A3 differs from angle A4. In this embodiment, for example, angle A3 can be larger than angle A4, but the disclosure is not limited to this.

[0041] The configuration of the light pattern shift layer 170 can further shift the light distribution in the Y direction. By comparing the Fig. 9A, Fig. 9B and Fig. 9C each with the Fig. 4A, Fig. 4B and Fig. 4C shows that if the light rays pass further through the light pattern shifting layer 170 of the embodiment, the light distribution is generally shifted in the direction Y. As shown in Fig. As shown in Figure 3A, since the projection screen 200 is a toric surface (that is, the curvature of the projection screen 200 along the X direction differs from that along the Z direction), the brightness uniformity of the displayed virtual image (such as the one shown in Figure 3A) can be adjusted by shifting the light distribution in the Y direction using the light pattern shift layer 170. Fig. 2 (virtual image IM) shown along the direction Z can be further improved.

[0042] Fig. 10A and Fig. Figure 10B are schematic cross-sectional views of a light source module according to a third embodiment of the disclosure. With reference to Fig. 10A and Fig. 10B uses the light source module 10B in this embodiment instead of the one in Fig. 1A and Fig. In the prism position 150 shown in Figure 1B, a further optical layer 130 is present. The structural design and function of the optical layer 130 are similar to those of the optical layer 100. More precisely, the light field distribution of the light beam after passing through the optical layer 130 is also uneven, and the influence of the optical layer 130 and the optical layer 100 on the light field distribution occurs in different spatial dimensions. For example, the optical layer 100 influences the light field distribution in the X direction, while the optical layer 130 influences the light field distribution in the Y direction.

[0043] Specifically, the optical layer 130 can contain 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 the Y direction and extend along the X direction. That is, the arrangement direction of the prism structures 120 of the optical layer 100 can be perpendicular to the arrangement direction of the prism structures 135 of the optical layer 130. The substrate 131 is provided with a side edge 131e1 and a side edge 131e2 on opposite sides along the Y direction. Each prism structure 135 has a structure surface ss1" facing side edge 131e1 and a structure surface ss2" facing side edge 131e2. An angle A1" is formed between each structure surface ss1" and the substrate surface 131s. Between each structure surface ss2" and the substrate surface 131s there is an angle A2".Since in the embodiment the distribution of the angle A1" and the angle A2" of each prism structure 135 of the optical layer 130 is similar to that of the optical layer 100, a detailed description can be found in the corresponding paragraphs of the aforementioned embodiments and is not repeated here.

[0044] It is particularly important to note that if the width of the projection screen is 200... Fig. If the optical layer 3A is enlarged in the Z direction (for example, doubled), different sections of the projection screen 200 arranged along the Z direction will exhibit different reflectances for light rays incident from the same direction. Therefore, by configuring the optical layer 130 described above, the entire light field distribution of the light source module 10B in the Y direction can also become uneven. In this way, the brightness uniformity of the displayed virtual image (such as the one in Fig. 2 (virtual image IM) shown in the direction of Z can be further improved.

[0045] Fig. Figure 11 is a schematic cross-sectional view of a light source module according to a fourth embodiment of the disclosure. Fig. Figure 12 is a schematic diagram illustrating the configuration relationship between the optical layer, the projection screen, and the viewing area. Fig. 11 illustrates. With reference to the Fig. 11 and Fig. 12. The difference between a light source module 10C of the embodiment and the light source module 10 in Fig. 1A in the position of the structural axis of the optical layer on the substrate surface. In particular, the structural axis SX'' of the embodiment does not overlap the symmetry axis of the substrate 101 in the X direction. That is, the structural axis SX'' is arranged offset from the symmetry axis of the substrate 101.

[0046] For example, in the embodiment, the width of the viewing area VA'' along direction X is, for example, one third of the width of the viewing area VA in Fig. 3A and is configured only for user USR1. In other words, the vertical axis VX2 of the viewing area VA'' is not oriented along the Y direction of the vertical axis VX1 of the projection screen 200. The virtual plane VP, formed by the vertical axes VX1 and VX2, intersects the substrate surface 101s at the intersection line IL'', which intersects the structure axis SX''.

[0047] It is particularly important to note that the midpoint CP of the intersection line IL'' defines the position of the structure axis SX'' on the substrate surface 101s along the direction X. The multitude of prism structures 120 of the optical layer 100C are arranged symmetrically relative to the structure axis SX''. In other words, the position of the mirror-symmetric center (i.e., the structure axis) of the prism structure distribution of the optical layer can be adjusted according to different application requirements (e.g., single-user or multi-user application) in order to optimize the brightness uniformity of the displayed virtual image.

[0048] Fig. Figure 13 is a schematic cross-sectional view of an optical layer according to a fifth embodiment of the disclosure. Fig. Figure 14 is a schematic cross-sectional view of another embodiment of the optical layer in Fig. 13. With reference to Fig. In embodiment 13, the substrate 101 of the optical layer 100D is provided with a plurality of prism structures 121 and a plurality of prism structures 122. These prism structures are arranged on the substrate surface 101s of the substrate 101 along the X direction and extend along the Y direction. The angle A1a of the prism structures 121 is not equal to the angle A1b of the prism structures 122. The angle A2a of the prism structures 121 is not equal to the angle A2b of the prism structures 122.

[0049] Due to the different structural configurations of prism structures 121 and 122 (i.e., different angles between the structure surfaces and the substrate surface 101s), tool changes are required during the fabrication of the prism structures with different angles. However, tool changes can easily lead to alignment tolerances, resulting in partial overlaps between the two types of prism structures with different angles, leading to noticeable light streaks on the layer surface, or to gaps between the two types of prism structures, leading to noticeable dark streaks on the layer surface.

[0050] To solve the aforementioned problem, in this embodiment, a plurality of prism structures 121'' and a plurality of prism structures 122'' can be provided between the prism structures 121 and the prism structures 122. The plurality of prism structures 121'' is arranged adjacent to the prism structures 121, and the plurality of prism structures 122'' is arranged adjacent to the prism structures 122. It is particularly noted that the prism structures 121'' and the prism structures 121 can be machined with the same tool, and that the prism structures 122'' and the prism structures 122 can be machined with the same tool. Therefore, the angle A1a'' and the angle A2a'' of prism structure 121'' can be equal to the angle A1a and the angle A2a of prism structure 121, respectively, and the angle A1b'' and the angle A2b'' of prism structures 122'' can be equal to the angle A1b and the angle A2a of prism structure 121, respectively.the angle A2b of the prism structures 122.

[0051] It is particularly important to note that the structure height H1'' of prism structures 121'' is smaller than the structure height H1 of prism structures 121, and the structure height H2'' of prism structures 122'' is smaller than the structure height H2 of prism structures 122. Since the dimensions of prism structures 121'' and 122'' are significantly smaller than those of prism structures 121 and 122, even if there is a partial overlap between prism structures 121'' and 122'' due to alignment tolerances during the tool change process, the resulting light streaks on the layer surface are not readily apparent.In other words, the regions in which the prism structures 121'' and 122'' are arranged can serve as a buffer area for the tool change process during the segmented machining of the prism structures 121 and 122, thereby improving the process flexibility and the quality of the surface appearance of the optical layer 100D.

[0052] However, the disclosure is not limited to this. In other embodiments, only the plurality of prism structures 121'' or the plurality of prism structures 122'' between the arrangement regions of the plurality of prism structures 121 and the plurality of prism structures 122 can be provided. Even if a misalignment occurs during the tool change process, such that a portion of the prism structures 121'' overlaps a portion of the prism structures 122 or a portion of the prism structures 122'' overlaps a portion of the prism structures 121, the bright streaks formed on the surface of the layer can become inconspicuous due to the large structural size difference between the overlapping prism structures. Thus, a similar technical effect to that of the embodiment can also be achieved.

[0053] In this embodiment, the plurality of prism structures 121'' have a width W1a along direction X, and the plurality of prism structures 122'' have a width W1b along direction X. Each of the prism structures 121 has a width W2a along direction X, and each of the prism structures 122 has a width W2b along direction X. Preferably, the ratio of width W1a to width W2a and the ratio of width W1b to width W2b are greater than or equal to 0.1 and less than 1.

[0054] It is particularly noted that the technical means disclosed in the embodiment can be applied to the splicing or connection regions between any two types of prism structures in the aforementioned embodiments, such as the connection region between prism structures 122 and 123, the connection region between prism structures 123 and 124 and / or the connection region between prism structures 124 and 125 in Fig. 1A, in order to achieve a similar technical effect to that of the embodiment.

[0055] The in Fig. Optical layer 100D shown in Figure 13 represents a configuration formed without misalignment during the tool change process. If misalignment occurs during the tool change process, an optical layer 100E is formed as shown in Figure 13. Fig. Figure 14 shows that in the optical layer 100E, the arrangement region of the plurality of prism structures 121'' partially overlaps the arrangement region of the plurality of prism structures 122''. That is, a portion of the prism structures 121'' and a portion of the prism structures 122'' are arranged alternately along the direction X.

[0056] Fig. Figure 15 is a schematic cross-sectional view of an optical layer according to a sixth embodiment of the disclosure. With reference to Fig. In contrast to the optical layer 100D, 15 takes up Fig. 13 in an optical layer 100F of the embodiment the structure height H1'' of each of the plurality of prism structures 121A'' decreases with increasing distance from the plurality of prism structures 121 and the structure height H2'' of each of the plurality of prism structures 122A'' decreases with increasing distance from the plurality of prism structures 122.

[0057] From another perspective, any two adjacent prism structures 121A'' are arranged at a distance P1, and this distance P1 decreases with increasing distance from the prism structures 121. Similarly, any two adjacent prism structures 122A'' are arranged at a distance P2, and this distance P2 decreases with increasing distance from the prism structures 122. By using a gradient design for the structure height and spacing of the prism structures 121A'' (or 122A''), it is possible to effectively prevent problems such as structural flaking or poor formation of the prism structures 121A'' and 122A'' caused by poor photoresist flow in the photolithography embossing process.

[0058] It should be noted that the gradient pattern of the structural height reduction of the prism structures 121A'' and the prism structures 122A'' can be adapted according to different process requirements or material selections and is not limited by the disclosure.

[0059] In summary, in the optical layer of one embodiment of the disclosure, the geometric shape or structural height of each prism structure varies according to its position on the substrate. The geometric shape distribution or structural height distribution of these prism structures allows light passing through the respective structure surfaces to fall onto different sections of the projection screen with varying light intensities. After being reflected from different sections of the projection screen, the virtual image formed at each eye point within the viewing area can exhibit a more uniform brightness distribution. In the optical layer of one embodiment of the disclosure, a third prism structure is provided between the first and second prism structures, with different angles.Since the angle of the third prism structure corresponds to that of the first or second prism structure, and the structure height of the third prism structure is less than that of the first and second prism structures, the region where the third prism structure is provided can serve as a buffer area for the segmented processing of the first and second prism structures. This contributes to improved process flexibility, and the fabricated optical layer can exhibit a desired surface appearance.

[0060] Those skilled in the art will understand that various modifications and variations can be made to the disclosed embodiments without deviating from the scope or fundamental concept of the disclosure. In light of the foregoing, the disclosure is intended to cover modifications and variations that fall within the scope of the following claims and their equivalents. [Description of symbols] 10, 10A, 10B, 10C, 11 Light source module 50 light sources 60 Diffusion position 100, 100'', 100A, 100C, 100D, 100E, 100F, 130 optical layer 101, 101'', 131, 141, 151, 171 substrate 101el, 101e2, 131e1, 131e2, 171e1, 171e2 side edge 101s, 101s'', 131s, 171s substrate surface 120, 120A, 121, 122, 123, 124, 125, 121'', 122'', 121A'', 122A'', 135, 143, 153 prism structure 140, 150 prism position 160 optical brightness enhancement layer 170 Light pattern shift layer 173 optical microstructure 200 projection screens 200p1, 200p2, 200p3, 200p4, 200p5 section A1, A2, A1'', A2'', A1a, A2a, A1a'', A2a'', A1b, A2b, A1b'', A2b'', A3, A4 angle CP Center EP Focus H, H1, H1'', H2, H2'' Structure height IL, IL'' Intersection line IN virtual image IMa, IN1b, IMc, IMd, IMe virtual partial image L1, L2, L3, L4, L5 Light beam P1, P2 distance ss1, ss2. ss1'', ss2'', ss3, ss4 Structure surface SX, SX'' structural axis USR1, USR2 User VA, VA'' viewing area VP virtual level VX1, VX2 upright axis W1a, W1b, W2a, W2b width X, Y, Z direction QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 8,390,760

[0024]

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