Optical illumination module for a display system

Abstract

The present disclosure relates to an optical illumination module for an automotive display system. The optical illumination module comprises a light generator for generating a light beam, a polarizing film for at least partially polarizing the light beam generated by the light generator, and a reflector sheet (104, 200a) disposed between the light generator and the polarizing film. The reflector sheet comprises a plurality of punch holes, each of the punch holes being configured to align with each of the light cells of the light generator. The reflector sheet is operable to receive the at least partially polarized light beam reflected from the polarizing film and redirect the polarized light beam toward the polarizing film.

Description

[Technical field]

[0001] The present disclosure relates to automobiles, and more particularly, to light source modules for automotive displays. [Background technology]

[0002] The automotive industry is increasingly moving towards using display technologies for entertainment and to display vehicle information. For example, a head-up display (HUD) projects an image from an image generating unit onto a mirror and reflects it onto the windshield or a combiner-type HUD to display vehicle information to the driver. A light source, such as a backlight unit, is required to display the content to the viewer. Another example is a HUD system that does not require a mirror. The displayed image is simply projected onto a glass panel. However, in automotive applications, one of the biggest challenges is often the excessive or lack of ambient lighting, which affects the quality of the image projection. Another challenge is the size of the light source for displays used in automobiles due to space constraints.

[0003] Traditionally, backlight units for display devices are made of reflectors and diffusers, or light guides and laminated foils. The challenge with traditional backlight units is that they have a wide angular distribution, which may not be suitable for automotive applications where space constraints are an issue. The wide angular distribution of light from a backlight module is particularly challenging for head-up display applications and display devices with small viewing angles, which are often used in automobiles to address space constraint issues.

[0004] Therefore, there is a need for automotive components for automotive display systems that overcome, or at least ameliorate, the challenges discussed above. Summary of the Invention [Problem to be solved by the invention]

[0005] The objective of the present disclosure is to improve the uniformity and brightness of the lighting module for HUD by adjusting the beam angle of the light rays reflected from the backlight unit to make the beam angle smaller or narrower, and to improve the contrast for local dimming effect. [Means for solving the problem]

[0006] The purpose of this disclosure is to a light generator operable to generate a light beam, the light generator comprising a plurality of light cells; a polarizing film operable to at least partially polarize the generated light beam; a reflective sheet having a plurality of punch holes through which the generated light can exit; a polarization rotation element operable to redirect the generated light beam; An optical illumination module for a display system comprising: The reflective sheet is Receives polarized and redirected light rays, Redirecting polarized light, redirected light, and light coming out through punch holes towards the polarizing film The problem is solved by an optical illumination module, characterized in that it is operable as follows.

[0007] The advantages of the above-mentioned aspects of the present disclosure provide an optical illumination module with illuminance and brightness homogeneity for displays, especially HUD systems and small display devices that are viewed through reflection on a transparent pane. As a result, the projected image is clear. Examples of suitable transparent panes include glass or tempered glass used as window glass, sunroof glass, and / or front and rear glass.

[0008] An optical illumination module as described above or as preferred above is preferred, in which The reflective sheet is disposed between the light generator and the polarizing film.

[0009] An advantage of the above aspect of the present disclosure is that by reflecting the polarized light from the polarizing film back and forth to the reflective sheet, the utilization of the light generated by the light generator is reused, resulting in uniformity and improved light efficiency.

[0010] An optical illumination module as described above or as preferred above is preferred, in which The light generator may comprise an LED array, a lens array, or a combination thereof.

[0011] An optical illumination module as described above or as preferred above is preferred, in which The lens array is disposed between the reflector sheet and the LED array.

[0012] An optical illumination module as described above or as preferred above is preferred, in which The reflector sheet and the lens array are integrated into a single device.

[0013] The advantages of the above aspects of the present disclosure result in an optical lighting module with homogenous illumination. The advantage of providing a reflector sheet and a lens array integrated into a single device means that individual LED components can be replaced by an LED array.

[0014] An optical illumination module as described above or as preferred above is preferred, in which The reflecting sheet may have a spherical or aspherical surface.

[0015] An optical illumination module as described above or as preferred above is preferred, in which The aspheric surface is a concave or arcuate profile.

[0016] An advantage of the above aspects of the present disclosure is the optimized control or influence of the direction of light rays reflected from the reflective sheeting.

[0017] An optical illumination module as described above or as preferred above is preferred, in which The reflective sheet is Perforated metal sheets, Plastic sheeting with a reflective coating, or Plastic sheet with reflective foil It is.

[0018] By virtue of the above aspects of the present disclosure, accurate and efficient reflective sheeting is obtained.

[0019] An optical illumination module as described above or as preferred above is preferred, in which The polarizing film (110) is a dual brightness enhancement film (DBEF).

[0020] An advantage of the above aspects of the present disclosure is that it optimizes the polarization of light rays and the reflection of the polarized light rays to achieve homogeneity by continuously recycling the reflected light rays while directing the reflected light rays along with the light rays generated from the light generator towards the top layer of the optical illumination module.

[0021] An optical illumination module as described above or as preferred above is preferred, in which The polarization rotating element is a retarder or a quarter wave plate.

[0022] An optical illumination module as described above or as preferred above is preferred, in which The polarization rotating element is made from a highly birefringent material.

[0023] An advantage of the above aspects of the present disclosure is that it increases the intensity of the light beam by increasing the energy.

[0024] An optical illumination module as described above or as preferred above is preferred, wherein the optical illumination module comprises: Optical diffuser placed in front of the polarizing film It further comprises:

[0025] An optical illumination module as described above or as preferred above is preferred, in which The display system is an automotive display system operable to project a virtual image onto a transparent pane.

[0026] An optical illumination module as described above or as preferred above is preferred, in which The display system is an automotive display system (400) embedded in a display device.

[0027] By virtue of the above aspects of the present disclosure, a homogeneous optical illumination module for use in an automotive display system is provided.

[0028] The purpose of this disclosure is to generating a light beam from a light generator, the light generator comprising a plurality of light cells; at least partially polarizing the light beam generated by the light generator with a polarizing film; redirecting a light beam generated by the light generator with a polarization rotation element; With reflective sheeting, an at least partially polarized light beam reflected from the polarizing film; ○ Light rays redirected by a polarization rotation element and a beam of light that is at least partially polarized; and a light beam redirected by a polarization rotation element; ○ The light ray passing through the light cell and exiting towards the polarizing film Redirecting and The problem is solved by a method of providing illumination for a display system, comprising:

[0029] The advantages of the above aspects of the present disclosure provide a lighting method that achieves uniformity, especially in HUD systems and small display devices.

[0030] A method for optical illumination as described above or as preferred above is preferred, said method comprising the steps of: Locally dimming each light cell by controlling the contrast of the light generated by each light cell Further includes:

[0031] An advantage of the above aspects of the present disclosure is that it improves the performance of the local dimming effect by adjusting the contrast of the light generated from each light cell.

[0032] Other objects and aspects of the present disclosure will become apparent from the following description of the embodiments, taken in conjunction with the accompanying drawings. [Brief description of the drawings]

[0033] [Figure 1A] 1 shows a side view of an optical illumination module according to a preferred embodiment. [Figure 1B] 1 illustrates a side view of an optical illumination module according to another preferred embodiment; [Figure 2A] 1 shows a reflector sheet according to a preferred embodiment. [Figure 2B] 1 shows a reflector sheet according to another preferred embodiment. [Figure 2C] FIG. 2 shows a top view of a reflector sheet integrated with a lens array according to a preferred embodiment. [Figure 2D] FIG. 2 illustrates a side view of a reflector sheet integrated with a lens array according to a preferred embodiment. [Figure 2E] FIG. 2 shows a perspective view of a reflector sheet integrated with a lens array according to a preferred embodiment. [Figure 3A]1 shows a schematic diagram of a system using an optical illumination module in an automotive display system according to a preferred embodiment. [Figure 3B] 1 shows a schematic diagram of a system using an optical illumination module in an automotive display system according to another preferred embodiment. [Figure 4] 1 shows a flow chart for providing optical illumination according to a preferred embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] In the various embodiments described with respect to the above figures, like reference numerals refer to like components among multiple perspective views and / or configurations.

[0035] The following detailed description is merely exemplary in nature and is not intended to limit the disclosure or the application and uses of the disclosure. Moreover, there is no intention to be bound by any theory presented in the preceding background of the disclosure or the following detailed description. The intent of the present disclosure is to present an optical illumination module for display systems, particularly HUD systems and small displays.

[0036] Hereinafter, the term "transparent" refers to a device or apparatus that has the property of being transparent, such that the background of the device or apparatus may be observable. Thus, a "transparent pane" allows a user to see both the image displayed on the display device and the background behind the display device, i.e., to see through to the background behind the transparent pane. Suitable examples of a "transparent pane" include glass or tempered glass.

[0037] Referring now to the accompanying drawings, Figures 1A and 1B show an optical illumination module 100a according to a preferred embodiment. The optical illumination module 100a comprises a light generator 106 for generating a light beam. The light generator 106 may further comprise a plurality of light cells 118, 118'. An example of the light generator 106 may be a light emitting diode (LED) array for emitting a light beam, more specifically, a plurality of LEDs represent each light cell 118, 118' for emitting a light beam. The light generator 106 may further comprise a lens covering each light cell 118, 118' or a lens array 120 disposed in front of the LED array. The lens array 120 acts as a collimator to increase the intensity of the light beam generated by the light generator 106. In an alternative embodiment, the lens array 120 may be a plurality of individual lenses forming an array by covering each LED.

[0038] The optical lighting modules 100a, 100b include a polarizing film 110. The polarizing film 110 is operable to at least partially polarize a light ray 116 in a direction (A), as shown in Figures 1A and 1B. As shown in Figures 1A and 1B, at least in part, a light ray 114 is transmitted through the polarizing film 110 toward a viewing area (B), such as a display layer 108. For clarity, the function of the polarizing film 110 is to reflect the light ray 116 toward the direction (A). A suitable example of the film 110 is a dual brightness enhancement film (DBEF).

[0039] The optical illumination module 100a further comprises a reflecting sheet 104 configured to align with each of the light cells 118, 118' of the light generator 106 so that the light rays can exit through the reflecting sheet 104. The reflecting sheet 104 is operable to redirect the polarized light rays 116 from the polarizing film 110 traveling towards the reflecting sheet 104 back to the polarizing film 110 along with the light rays generated from the light generator 106. Due to this constant reflection of polarized light rays and redirecting the reflected light rays along with the light rays generated from the light generator 106, the light rays within the optical illumination module 100 are at least partially recycled before transmitting the light rays 114 towards the viewing range (B).

[0040] In one embodiment, the reflector sheet 104 is disposed between the lens array 120 and the LED array 106. In another exemplary embodiment, as shown in FIG. 1B, the reflector sheet 104′ and the lens array 120 may be integrated into a single device disposed between the polarizing film 110 and the light generator 106 to affect the reflection and redirection of the light rays 116 traveling between the polarizing film 110, the lens array 120, and the light generator 106. Advantageously, both the embodiments shown in FIG. 1A and FIG. 1B achieve illumination homogeneity through this light recycling process provided by the reflector sheet 104.

[0041] The optical illumination module 100b further comprises a polarization rotation element 112 operable to change the polarization of the generated light beam. Examples of the polarization rotation element 112 include a retarder or a quarter wave plate. Preferably, the polarization rotation element 112 is made of a highly birefringent material to control the redirection of the polarization of the light beam.

[0042] In another embodiment, an optical diffuser (not shown) for redirecting light rays may be included in the polarizing film of the display layer near the viewing area (B).

[0043] In an exemplary embodiment, the polarizing film 110 is preferably disposed 3 mm to 5 mm, more preferably 4.7 mm, in front of the reflective sheet.

[0044] In another exemplary embodiment, the reflector sheet 104 is disposed between the light generator 106 and the polarizing film 110. Advantageously, disposing the reflector sheet 104 between the light generator 106 and the polarizing film 110 increases illumination homogeneity through a light recycling process within the optical illumination module 100a.

[0045] 1B, the optical illumination system 100b exhibits an integrated reflector sheet 104' that includes a spherical or aspherical surface having a plurality of perforated sheets and a lens array 120.

[0046] FIG. 2A shows a reflective sheet 200a according to a preferred embodiment. The reflective sheet 200a comprises a plurality of punch holes 202, 202'. Preferably, the plurality of punch holes 202, 202' have an equilateral geometric shape. Examples of equilateral geometric shapes include a hexagon, a pentagon, or a square. The punch holes 202, 202' may be circular as shown in FIG. 2A, and in an alternative embodiment as shown in FIG. 2B, the punch holes 202, 202' are square.

[0047] Preferably, to achieve optimal results, the outer dimensions are in the range of 3mm x 3mm to 5mm x 5mm, and the inner dimensions of the punch holes can be 1.6mm x 1.6mm to 2mm x 2mm. In an exemplary embodiment, the reflective sheet has a dimension of 40mm x 40mm, and each single unit of the punch holes 202 has an outer dimension of 4mm x 4mm, and the inner dimensions of the punch holes are 1.64mm x 1.64mm, as shown in FIG. 2B. Advantageously, the above-mentioned configuration optimizes the reception of the polarized light beam 116 and the generation of the light beam from the light generator 106 to achieve homogeneity. The above description provides an exemplary embodiment of the present disclosure to optimize the results of achieving an optical lighting module that provides homogeneous illumination for automotive displays to counter the effects of wide-angle distribution. However, it should be understood by those skilled in the art that these dimensions of the reflective sheet are not intended to limit the inventive concept of the present disclosure.

[0048] In an exemplary embodiment, the reflective sheet 200a has an aspheric surface. The advantage of an aspheric surface is that it controls the direction of the light rays generated by the light generator so that image quality is improved. This advantage is particularly important to the automotive industry, where it is desired to display clear images for vehicle or warning information. Examples of aspheric surfaces include concave or arcuate profiles. However, non-aspheric surfaces may achieve reasonable, though less than optimal, results without departing from the scope and spirit of the present disclosure.

[0049] In an exemplary embodiment, the reflective sheet 200a can be a metal perforated sheet made by a metal sheet stamping process. In another exemplary embodiment, the reflective sheet 200a is a plastic sheet with a reflective coating. In yet another exemplary embodiment, the reflective sheet 200a is a plastic sheet with a reflective foil.

[0050] In various embodiments discussed herein, the optical illumination module 100 functions as a backlight unit that provides illumination to a viewing area (B) defined by a display layer 108, as shown in Figures 1A and 1B. An example of a suitable display layer 108 includes a thin film transistor (TFT) display layer.

[0051] In an exemplary embodiment, the reflector sheet 200a is placed in front of the lens array 120 and the LED array 106 or light generator 106 as shown in FIG. 1A. In another exemplary embodiment as shown in FIG. 1B, the reflector sheet 200a is provided as a single device or integrated reflector sheet 200c such as shown in FIG. 2C, which shows a top view of the integrated reflector sheet 200c. FIG. 2D shows a side view of an integrated reflector sheet 200d, in which a lens array is integrated with the reflector sheet 104, 104'. In yet another exemplary embodiment, the reflector sheet 200a is provided as a single device as shown in FIG. 2C and FIG. 2D, in which individual lenses are integrated with each of the punch holes 202, 202' of the reflector sheet 200a, to achieve a collimation effect from the lenses combined with control of the reflective and redirecting properties of the reflector sheet 200a by providing a single device. FIG. 2E shows a perspective view illustrating an exemplary embodiment of the reflector sheet 200a integrated with a lens array.

[0052] Turning now to FIG. 3A , which shows a schematic diagram of a system 300 using the optical illumination module 100 in an automobile, the system 300 represents a head-up display (HUD) system that includes a reflector 302, 302′ and an image generation unit 306. In this exemplary embodiment, the optical illumination module 100 may be disposed within the image generation unit 306. An image generated from the image generation unit 306 is reflected via the reflector 302, 302′ to a transparent pane 304 of the automobile to form a virtual image 310 that can be viewed by a viewer 312. Examples of the transparent pane 304 include a glass or tempered glass sheet that may be used as an automobile window pane, an automobile sunroof, and / or an automobile windshield or rear windshield.

[0053] In another exemplary embodiment, as shown in FIG. 3B, which illustrates another exemplary embodiment of a HUD system 300b, for a type of head-up display that does not require an additional mirror or reflector to reflect light rays from the image generating unit, the virtual image 310 from the HUD system is simply projected onto a transparent pane that can be viewed directly by the driver 312.

[0054] FIG. 4 shows a flow chart 400 for providing illumination to a display system comprising an optical illumination module 104, 104′, 200a-200e as disclosed. At 402, a light generator generates a light beam from the light generator. The light generator comprises a plurality of light cells. At a next step 404, the light beam generated from the light generator is at least partially polarized by a polarizing film. At 406, the light beam is redirected by a polarization rotation element. At a next step 408, a reflecting sheet receives the at least partially polarized light beam and the light beam redirected by the polarization rotation element through the reflecting sheet. At a next step 410, the light beam received by the reflecting sheet, i.e. the at least partially polarized light beam and the light beam redirected by the polarization rotation element, together with the light beam emitted from the light cells of the light generator, are redirected towards the polarizing film.

[0055] In a further operational step 412, the method further comprises the step of locally dimming each light cell by controlling the contrast of the light emitted from each light cell.

[0056] It can thus be seen that an optical lighting module is provided with a uniform illuminance level suitable for small viewing range applications, especially automotive display applications. Due to the small beam reflection angle, the polarized light rays are redistributed within the optical lighting module to achieve uniform illumination, i.e., homogeneity. Furthermore, the design of the reflective sheet improves image quality by controlling the redistribution of the light rays and resulting in a sharper image compared to conventional direct-type backlight units known in the art.

[0057] Further, it should be understood that the exemplary embodiments are merely examples and are not intended to limit the scope, applicability, operation, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the exemplary embodiments of the invention, and it will be understood that various changes can be made in the function and arrangement of elements and method of operation described in the exemplary embodiments without departing from the scope of the invention as defined in the appended claims. [Explanation of symbols]

[0058] 100a Optical illumination module in preferred embodiment 100b Optical illumination module in another preferred embodiment 102 Printed Circuit Board (PCB) 104 Reflective Sheet 104' Integrated reflective sheeting 106 Light Generator 108 Display layer 110 Polarizing Film 112 Quarter Wave Plate 114 Ray of light 116 Polarized Light 118, 118' Optical cell 120 Lens Array 200a Reflective sheet with equilateral punch holes 202, 202' punch hole 204 Aspheric or surface of reflective sheet 200b Reflective sheet with equilateral punch holes 200c Reflective sheet top view Side view of 200d reflective sheet 300a, 300b Head-up display system 302, 302' reflector 304 Glass Panel 306 Image Generation Unit 308 Reflected Light 310 Virtual Image 312 The Viewer's Eyes 400 Flowchart

Claims

1. An optical illumination module (100a, 100b) for a display system (300), comprising: The optical lighting modules (100a, 100b) include: a light generator (106) operable to generate a light beam (114), said light generator (106) comprising a plurality of light cells (118, 118'); a polarizing film (110) operable to at least partially polarize the generated light beam (114); a reflective sheet (104, 104', 200a-d) having a plurality of punch holes (202, 202') through which the generated light beam (114) can exit; a polarization rotation element (112) operable to invert the polarization direction of the generated light beam (114); Equipped with In the optical illumination module (100a, 100b), The reflective sheet (104, 104', 200a-d) receiving the polarized light beam (116) and the polarization-switched light beam; The polarized light (116), the light whose polarization direction has been changed, and the light (114) that has passed through the punch holes (202, 202') are directed to the polarizing film (110) to change the polarization direction. It is possible to operate as follows: the polarizing film (110) further comprises an optical diffuser disposed in front of the polarizing film (110), the polarizing film (110) being disposed 3 mm to 5 mm in front of the reflecting sheet, or 4.7 mm in front of the reflecting sheet; An optical illumination module (100a, 100b).

2. The optical illumination module (100a, 100b) of claim 1, wherein the reflective sheet (104, 104', 200a-d) is disposed between the light generator (106) and the polarizing film (110).

3. The optical illumination module (100a, 100b) of claim 1 or 2, wherein the light generator (106) comprises an LED array, a lens array, or a combination thereof.

4. An optical lighting module (100a, 100b) as described in claim 3, wherein the reflective sheet (104, 104', 200a-d) is positioned between the lens array and the LED array.

5. The optical illumination module (100a, 100b) of claim 3, wherein the reflector sheet (104, 104', 200a-d) and the lens array are integrated into a single device.

6. The optical lighting module (100a, 100b) according to any one of the preceding claims, wherein the reflector sheet (104, 200a) has a spherical or aspherical surface (204).

7. The optical illumination module (100a, 100b) of claim 6, wherein the aspheric surface is a concave or arcuate profile.

8. The reflective sheet (104, 104', 200a-d) Metal perforated sheet, A plastic sheet with a reflective coating, or Plastic sheet with reflective foil The optical lighting module (100a, 100b) according to any one of claims 1 to 7,

9. The optical lighting module (100a, 100b) of any one of claims 1 to 8, wherein the polarizing film (110) is a dual brightness enhancement film (DBEF).

10. The optical illumination module (100a, 100b) of any one of claims 1 to 9, wherein the polarization rotation element (112) is a retarder or a quarter wave plate.

11. The optical illumination module (100a, 100b) of any one of claims 1 to 10, wherein the polarization rotating element (112) is made of a birefringent material.

12. The optical illumination module (100a, 100b) of any one of claims 1 to 11, wherein the display system is an automotive display system (300) operable to project a virtual image (310) onto a transparent pane (304).

13. A method of providing illumination for a display system (300), the method comprising: generating a light beam from a light generator, the light generator comprising a plurality of light cells; At least partially polarizing (404) the light beam generated by the light generator with a polarizing film (110); changing the polarization direction of the light beam generated by the light generator by a polarization rotation element (406); With reflective sheeting, the at least partially polarized light beam reflected from the polarizing film (110); A light beam whose polarization direction has been changed by the polarization rotation element; receiving (408); the at least partially polarized light beam; and A light beam whose polarization direction has been changed by the polarization rotation element; and A light ray passing through the light cell and exiting towards the polarizing film (110); incident on the polarizing film (110); Including, the polarizing film (110) further comprises an optical diffuser disposed in front of the polarizing film (110), the polarizing film (110) being disposed 3 mm to 5 mm in front of the reflecting sheet, or 4.7 mm in front of the reflecting sheet; method.

14. 14. The method of claim 13, further comprising the step of locally dimming each light cell by controlling the contrast of the light emitted from each light cell (412).

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