Holographic windscreen display system and method of controlling the same

Abstract

A holographic windshield display system and a control method thereof are provided. The holographic windshield display system includes a windshield, a holographic optical element (HOE) laminated on the windshield, a projection module for projecting an image onto the HOE, and a controller for controlling the projection module. The projection module includes at least one light source module including light sources having different center wavelengths, and a monitoring device for monitoring a change in at least one characteristic of a temperature and a wavelength of the at least one light source module. The controller drives, based on the changed characteristic of the at least one light source module, a light source having a center wavelength matching a center wavelength of a diffraction wavelength of the HOE, among the light sources having different center wavelengths.

Description

Technical Field

[0001] This specification relates to a holographic windshield display system and its control method, and more specifically, to a holographic windshield display system and its control method including a projection module capable of maintaining a center wavelength regardless of temperature changes. Background Technology

[0002] Holographic head-up displays (HUDs) include holographic optics (HOEs).

[0003] In the case of a vehicle HUD, the HOE is included in the windshield and includes a pre-formed interference pattern that selectively responds to light incident from the HUD at a specific angle and having a specific wavelength, thereby producing diffraction of a desired shape.

[0004] Interference patterns can be formed such that the HOE satisfies the Bragg matching condition of the incident light, thereby enabling high-efficiency light diffraction under specific conditions.

[0005] HOE is an optical element that utilizes the diffraction properties of light and has the advantage of providing a large screen for the driver while reducing the size of the HUD system.

[0006] On the other hand, because HOE is sensitive to the wavelength of incident light, laser sources are mainly used in holographic HUDs.

[0007] Since HOEs are diffractive optical elements and are sensitive to the wavelength of incident light, even when the path of the incident light is the same, changes in wavelength will result in different diffraction angles.

[0008] Therefore, from the driver's perspective, the image appears to move. Furthermore, each red (R), green (G), and blue (B) laser exhibits a different wavelength change even under the same temperature variation.

[0009] Therefore, changes in the diffraction angle in the HOE result in color separation in the image.

[0010] Figure 1 An example of color separation of an image generated by a laser projector-based holographic HUD using R+G laser diodes is shown, according to existing technology.

[0011] It can be seen that, Figure 1 In the input image shown in (a) (image from a laser projector), the R and G images are displayed identically to prevent color separation, but in Figure 1 In the output image shown in (b) (the image projected onto the HOE), the R image is displayed as shifted below the G image, resulting in color separation.

[0012] Meanwhile, research has recently been conducted on integrating holographic windshield display systems into vehicles.

[0013] Holographic windshield display systems typically include a projection module and a HOE (Honor of the Image), with the HOE serving as a transparent screen laminated onto the vehicle's windshield in the form of a film.

[0014] Therefore, the image projected from the projection module is projected onto the HOE and diffracted toward the passenger's eyes.

[0015] To improve the efficiency of the holographic windshield display system, it is preferable to match the center wavelength of the projection module with the center wavelength of the HOE diffraction wavelength.

[0016] However, as mentioned above, since all light sources have a center wavelength that varies with temperature, the efficiency of the holographic windshield display system will vary with temperature.

[0017] Therefore, when the efficiency for each R, G, and B is different, the white balance may be disrupted, color reproduction may be altered, and the brightness of the image formed on the HOE may be reduced. Summary of the Invention

[0018] This disclosure aims to at least address the aforementioned issues.

[0019] This disclosure also aims to provide a holographic windshield display system including a projection module capable of maintaining a center wavelength regardless of temperature changes.

[0020] This disclosure also aims to provide a control method for a holographic windshield display system, which includes a projection module capable of maintaining a center wavelength regardless of temperature changes.

[0021] In a typical embodiment, a holographic windshield display system includes: a windshield on which a holographic optical element (HOE) is laminated; a projection module configured to project an image onto the HOE; and a controller configured to control the projection module, wherein the projection module includes: at least one light source module comprising a plurality of light sources having different center wavelengths; and a monitoring device configured to monitor changes in at least one characteristic of the temperature and wavelength of the at least one light source module, and wherein the controller is further configured to drive a light source among the plurality of light sources having different center wavelengths whose center wavelength matches the center wavelength of the diffraction wavelength of the HOE, based on the changing characteristics of the at least one light source module.

[0022] The holographic windshield display system may also include: a memory configured to store a table of driving light sources based on the changing characteristics of at least one light source module.

[0023] The difference between the center wavelengths of multiple different light sources can range from 2 nm to 10 nm.

[0024] At least one light source module may include a red (R) laser light source module, a green (G) laser light source module, and a blue (B) laser light source module.

[0025] The projection module may further include: a display panel; an illumination optics system configured to transmit light from at least one light source module to the display panel; and a projection optics system configured to provide an image generated on the display panel to the HOE.

[0026] At least one light source module may include a red (R) laser light source module, a green (G) laser light source module, and a blue (B) laser light source module.

[0027] The projection module may further include: a display panel; an illumination optics system configured to transmit light from at least one light source module to the display panel; and a projection optics system configured to provide an image generated on the display panel to the HOE.

[0028] At least one light source module may include a red (R) laser light source module, a green (G) laser light source module, and a blue (B) laser light source module.

[0029] In another general aspect, a control method for a holographic windshield display system is provided. The holographic windshield display system includes: a windshield on which a holographic optical element (HOE) is laminated; a projection module including at least one light source module and a monitoring device, wherein the at least one light source module includes multiple light sources with different center wavelengths, and the control method includes: monitoring changes in at least one characteristic of the temperature and wavelength of the at least one light source module by the monitoring device; projecting an image onto the HOE by the projection module; controlling the projection module by a controller; and driving a light source among the multiple light sources with different center wavelengths whose center wavelength matches the center wavelength of the diffraction wavelength of the HOE, based on the changing characteristics of the at least one light source module.

[0030] The control method may further include: setting up a memory configured to store a table of driving light sources based on the changing characteristics of at least one light source module.

[0031] The difference between the center wavelengths of multiple different light sources can range from 2 nm to 10 nm.

[0032] At least one light source module may include a red (R) laser light source module, a green (G) laser light source module, and a blue (B) laser light source module.

[0033] The projection module may include: a display panel; an illumination optics system configured to transmit light from at least one light source module to the display panel; and a projection optics system configured to provide an image generated on the display panel to the HOE.

[0034] In the holographic windshield display system and control method according to various embodiments of the present disclosure, when a change in the characteristics of the light source module is detected, a light source whose center wavelength matches the center wavelength of the diffraction wavelength of the HOE is driven, and the driving of the light source with the changed characteristics can be terminated.

[0035] Therefore, since the light source in the memory is configured to be automatically driven according to the changes in the characteristics of the light source module, the reduction in brightness and the change in color of the holographic windshield display caused by the changes in the characteristics of the light source module can be effectively prevented.

[0036] The effects that can be obtained from this disclosure are not limited to those described above, and those skilled in the art to which this disclosure pertains will be able to clearly understand other effects not described based on the following description. Attached Figure Description

[0037] The accompanying drawings are included as part of the detailed description to aid in understanding this disclosure. The drawings provide various embodiments of the disclosure and, together with the detailed description, illustrate the contents of the disclosure. In the drawings: Figure 1 This is a view showing an example of a holographic image display (HID) image that uses two color lasers in a typical HID and where color separation occurs due to changes in the wavelength of the light source when a temperature change occurs; Figure 2 This is a view showing the configuration of a holographic windshield display system according to an embodiment of the present disclosure; Figure 3 This is a view illustrating an example of the process of manufacturing a holographic windshield display included in a holographic windshield display system according to an embodiment of the present disclosure; Figure 4 It is shown Figure 2 A view showing the detailed configuration of the blue (B) laser source module shown; Figure 5 This is an example illustrating the state of a holographic windshield display system installed in a vehicle according to an embodiment of the present disclosure; and Figure 6 This is another example illustrating the state of a holographic windshield display system installed in a vehicle according to an embodiment of the present disclosure. Detailed Implementation

[0038] In the following, various embodiments disclosed herein will be described in detail with reference to the accompanying drawings, and the same or similar components will be indicated by the same reference numerals regardless of the reference numerals, and repeated descriptions thereof will be omitted.

[0039] To facilitate the preparation of the instruction manual, the suffixes “module” and “unit” are given or used interchangeably with those used in the following description, and do not have different meanings or functions from each other.

[0040] Furthermore, when describing the various embodiments disclosed in this disclosure, detailed descriptions of related known technologies will be omitted when it is determined that such detailed descriptions may obscure the essence of the various embodiments disclosed in this disclosure.

[0041] Furthermore, the accompanying drawings are provided only for easy understanding of the various embodiments disclosed herein, and it should be understood that the technical spirit disclosed herein is not limited to the drawings, and all changes, equivalents or substitutions included in the spirit and scope of this disclosure are included in the drawings.

[0042] Terms including ordinal numbers such as first or second can be used to describe various components, but these components are not limited by the terms. These terms are used only for the purpose of distinguishing one component from another.

[0043] When a component is described as being “connected” or “coupled” to another component, it should be understood that the component may be directly connected or directly coupled to the other component, but the other component may be present in between.

[0044] On the other hand, when a component is described as being "directly connected" or "directly coupled" to another component, it should be understood that there is no other component in between.

[0045] Unless the context clearly indicates otherwise, the singular includes the plural.

[0046] In this application, it should be understood that the terms "comprising" and "having" are intended to specify the presence of the features, quantities, steps, operations, components, parts or combinations thereof described in this specification, but do not preclude the possibility of the presence or addition of one or more other features, quantities, steps, operations, components, parts or combinations thereof.

[0047] Various embodiments of this disclosure will be described below with reference to the accompanying drawings.

[0048] Figure 2 This is a view showing the configuration of a holographic windshield display system according to an embodiment of the present disclosure.

[0049] Figure 3This is a view illustrating an example of the process of manufacturing a holographic windshield display included in a holographic windshield display system according to an embodiment of the present disclosure.

[0050] Figure 4 It is shown Figure 2 A view showing the detailed configuration of the blue (B) laser source module.

[0051] Figure 5 This is an example showing the state of a holographic windshield display system installed in a vehicle according to an embodiment of the present disclosure.

[0052] Figure 6 This is another example illustrating the state of a holographic windshield display system installed in a vehicle according to an embodiment of the present disclosure.

[0053] First, such as Figure 2 As shown, the holographic windshield display system according to an embodiment of the present disclosure includes: a windshield 100, on which a holographic optical element (HOE) 30 is laminated in the form of a film; a projection module 200 for projecting an image onto the HOE 30; and a controller 240 for controlling the projection module 200.

[0054] First, refer to Figure 3 An example describing the process of manufacturing a windshield 100 laminated with HOE 30.

[0055] First, a first bonding process is performed: the first component 2 and the first component 3 are manufactured by sequentially laminating glass 10, polyvinyl butyral (PVB) film 20, first barrier film 40, second barrier film 40, PVB film 20 and glass 10 and bonding the laminates at a first bonding temperature (e.g., above 150°C) and under high pressure.

[0056] Subsequently, a separation process is performed: the first barrier film 40 is separated from the second barrier film 40 to separate the first component 2 and the first component 3 into the first bonding glass and the second bonding glass.

[0057] Subsequently, a second bonding process is performed: two low-temperature bonding films 22 are arranged between the first barrier film 40 of the first bonding glass and the second barrier film 40 of the second bonding glass, a film-shaped HOE 30 is arranged between the two low-temperature bonding films 22, and then the laminate is bonded at a second bonding temperature (e.g., in the range of 50°C to 100°C) below the first bonding temperature.

[0058] The first and second bonding processes can be performed using an autoclave, and the film-like HOE 30 can be manufactured by roll-to-roll imprinting.

[0059] The first bonding process may be performed after the initial bonding process is performed at a temperature below the first bonding temperature, and the second bonding process may be performed after the initial bonding process is performed at a temperature below the second bonding temperature.

[0060] The low-temperature bonding film can be formed from a material that can perform the bonding process at a lower temperature than that of the PVB film 20.

[0061] Materials used for the low-temperature bonding film 22 may include ethylene-vinyl acetate (EVA) film, thermosetting polymers, photocurable polymers, etc.

[0062] HOE 30 may include a pre-formed interference pattern that selectively responds to light incident at a specific angle and having a specific wavelength, thereby producing diffraction of a desired shape.

[0063] In this disclosure, the projection module 200 for projecting an image onto the HOE 30 is configured such that at least one light source module 210 includes a plurality of light sources (light source 1, light source 2, light source 3, light source 4, etc.) with different center wavelengths.

[0064] Figure 5 and Figure 6 An example of three of the projection modules 200 installed inside a vehicle is shown.

[0065] The holographic windshield display system may also include a reflector 220, as needed. Figure 5 As shown.

[0066] The following will describe an example in which three projection modules 200 are set, but the number of projection modules 200 installed inside the vehicle is not limited.

[0067] Each projection module 200 includes at least one light source module 210 as described above.

[0068] Figure 2 Each projection module 200 is shown to have three light source modules 210R, 210G and 210B.

[0069] In the following description, an example in which each projection module 200 includes three light source modules 210R, 210G and 210B will be described, but the number of light source modules 210 installed inside each projection module 200 is not limited.

[0070] Each projection module 200 includes a red (R) laser light source module 210R, a green (G) laser light source module 210G, and a blue (B) laser light source module 210B.

[0071] In addition, each of the light source modules 210R, 210G and 210B includes multiple light sources (light source 1, light source 2, light source 3, light source 4, etc.) with different center wavelengths.

[0072] Figure 4 An example is shown in which the blue (B) laser light source module 210B includes multiple light sources (light source 1, light source 2, light source 3, light source 4, etc.).

[0073] Multiple light sources (light source 1, light source 2, light source 3, light source 4, etc.) disposed in each of the light source modules 210R, 210G and 210B can have center wavelengths that differ from each other by a constant difference, which is in the range of 2 nm to 10 nm.

[0074] Figure 4 The difference between the center wavelengths of multiple light sources (light source 1, light source 2, light source 3, light source 4, etc.) is shown to be 3 nm.

[0075] refer to Figure 4 The center wavelength of light source 1 is 400 nm, the center wavelength of light source 2 is 403 nm, the center wavelength of light source 3 is 406 nm, and the center wavelength of light source 4 is 409 nm.

[0076] The projection module 200 includes a monitoring unit 230 (e.g., a monitoring device) for monitoring changes in at least one characteristic of the temperature and wavelength of at least one light source module 210.

[0077] In addition, the holographic windshield display system includes a controller 240, which is used to drive a light source among a plurality of light sources (light source 1, light source 2, light source 3, light source 4, etc.) with different center wavelengths, based on the changing characteristics of at least one light source module 210, that has a center wavelength that matches the center wavelength of the diffraction wavelength of HOE 30.

[0078] The controller 240 can be located in the projection module 200.

[0079] In addition, the holographic windshield display system may also include a memory 250 for storing a table of driving light sources with varying characteristics according to at least one light source module.

[0080] The memory 250 can be located in the projection module 200.

[0081] Figure 2 The memory 250 and controller 240 are shown as separate elements, but this is not limiting, and the memory 250 may be included as part of the controller 240.

[0082] The projection module 200 may further include: a display panel 260; an illumination optics system 270 for transmitting light from at least one light source module 210 to the display panel 260; and a projection optics system 280 for providing an image generated by the display panel 260 to the HOE 30.

[0083] There are no particular restrictions on the display panel 260, but it can be one of digital light processing (DLP), microelectromechanical systems (MEMS), scanner, liquid crystal on silicon, and liquid crystal display (LCD).

[0084] In addition, the projection module 200 may also include: a light source driver 291 for driving the light source module 210; and a panel driver 293 for driving the display panel 260.

[0085] In a holographic windshield display system with this configuration, when the monitoring unit 230 detects a change in the characteristics of the light source module 210 (e.g., a change in temperature and / or wavelength), the controller 240, which receives a signal from the monitoring unit 230, can transmit a drive signal to the light source driver 291 to drive a new light source that will be driven according to the changed characteristics of the light source module 210, based on the drive light source table stored in the memory 250.

[0086] Therefore, it is possible to drive a light source whose center wavelength matches the center wavelength of the diffraction wavelength of HOE 30, and to stop driving a light source with changing characteristics.

[0087] It will be apparent to those skilled in the art that this disclosure may be embodied in other specific forms without departing from its essential characteristics. Therefore, the above detailed description should not be construed as restrictive in any way, but rather as illustrative. The scope of this disclosure should be determined by the reasonable construction of the appended claims, and all variations within the scope of equivalents in this disclosure are intended to be included within this disclosure.

Claims

1. A holographic windshield display system, comprising: The windshield has a holographic optical element (HOE) laminated on it. A projection module is configured to project an image onto the HOE; as well as The controller is configured to control the projection module. The projection module includes: At least one light source module, comprising multiple light sources with different center wavelengths; and A monitoring device is configured to monitor changes in at least one characteristic of the at least one light source module, namely temperature and wavelength. The controller is further configured to drive a light source among the plurality of light sources having different center wavelengths, whose center wavelength matches the center wavelength of the diffraction wavelength of the HOE, based on the changing characteristics of the at least one light source module.

2. The holographic windshield display system according to claim 1 further includes: The memory is configured to store a table of driving light sources based on the changing characteristics of the at least one light source module.

3. The holographic windshield display system according to claim 2, wherein, The difference between the center wavelengths of the different light sources is in the range of 2 nm to 10 nm.

4. The holographic windshield display system according to any one of claims 1 to 3, wherein, The at least one light source module includes a red laser light source module, a green laser light source module, and a blue laser light source module.

5. The holographic windshield display system according to claim 4, wherein, The projection module also includes: Display panel; An illumination optical system is configured to transmit light from the at least one light source module to the display panel; and A projection optics system is configured to provide the HOE with an image generated on the display panel.

6. A control method for a holographic windshield display system, the holographic windshield display system comprising: The windshield has a holographic optical element (HOE) laminated on it. A projection module includes at least one light source module and a monitoring device, wherein the at least one light source module includes multiple light sources with different center wavelengths, and the control method includes: The monitoring device monitors changes in at least one characteristic of the at least one light source module, namely temperature and wavelength. The projection module projects the image onto the HOE; The projection module is controlled by a controller; and The controller drives a light source among the plurality of light sources with different center wavelengths, whose center wavelength matches the center wavelength of the diffraction wavelength of the HOE, based on the changing characteristics of the at least one light source module.

7. The control method according to claim 6 further includes: A memory is provided, the memory being configured to store a table of driving light sources based on the changing characteristics of the at least one light source module.

8. The control method according to claim 7, wherein, The difference between the center wavelengths of the different light sources is in the range of 2 nm to 10 nm.

9. The control method according to any one of claims 6 to 8, wherein, The at least one light source module includes a red laser light source module, a green laser light source module, and a blue laser light source module.

10. The control method according to claim 9, wherein, The projection module also includes: Display panel; An illumination optical system is configured to transmit light from the at least one light source module to the display panel; and A projection optics system is configured to provide the HOE with an image generated on the display panel.

Images