Image generation unit and head-up display device

Abstract

The present disclosure relates to an image generating unit and a head-up display device. In one aspect, the image generating unit comprises: an illumination device for providing light rays; a first beam splitter arranged at an exit side of the illumination device for reflecting first S light and transmitting first P light among the light rays; a first display device arranged to receive the first S light for converting it into second P light and reflecting the second P light to the first beam splitter; a second display device arranged to receive the first P light for converting it into second S light and reflecting the second S light to the first beam splitter; a first diffuse reflector arranged downstream of the light path of the first beam splitter and configured to image one of the second S light and the second P light; and a second diffuse reflector arranged downstream of the light path of the first beam splitter and configured to image the other one. Thereby, the head-up display device can have a smaller volume, a lower power consumption and a larger field of view.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of display, in particular, to an image generation unit and a head-up display device comprising the same. BACKGROUND

[0002] Head-up display (HUD) devices are widely used in vehicles and other transportation tools, which are used to display information such as vehicle conditions on the imaging reflection part such as windshield glass of the transportation tools, so that the driver can obtain the information while maintaining continuous attention to the road conditions.

[0003] Generally, the HUD device comprises a picture generation unit (PGU) and a reflection unit. The PGU is used to emit image light rays towards the reflection unit, and the reflection unit is used to project the image light rays onto the windshield glass. In this way, the image light rays are reflected by the windshield glass to reach the eyebox, thereby forming a virtual image for the driver to observe on the backward extension line of the reflected image light rays.

[0004] The liquid crystal on silicon (LCOS) PGU is a PGU using LCOS which is a reflective polarization device, which can provide a clear image with high resolution. A bifocal HUD device using the LCOS PGU can be used to obtain two virtual images at different distances, so that the virtual images can be integrated with real scenes at different distances, thereby providing a better driving experience.

[0005] However, the bifocal HUD device using the LCOS PGU under the existing architecture has the problems of large volume, high power consumption and small field of view angle. SUMMARY

[0006] This section provides a general summary of the present disclosure, rather than a comprehensive disclosure of the full scope or all features of the present disclosure.

[0007] The purpose of the present disclosure is to provide a PGU which can make the volume of the HUD device small, the power consumption low and the field of view angle large.

[0008] In order to achieve the above-mentioned purpose, according to an aspect of the present disclosure, a PGU is provided, which comprises:

[0009] An illumination device for providing light rays;

[0010] A first beam splitter disposed on the light emitting side of the illumination device for reflecting first S light and transmitting first P light in the light rays;

[0011] a first display device configured to receive the first S light from the first beamsplitter for converting it to second P light and reflecting the second P light to the first beamsplitter;

[0012] a second display device configured to receive the first P light from the first beamsplitter for converting it to second S light and reflecting the second S light to the first beamsplitter;

[0013] a first diffuse reflector disposed downstream of the optical path of the first beamsplitter and configured to image one of the second S light and the second P light; and

[0014] a second diffuse reflector disposed downstream of the optical path of the first beamsplitter and configured to image the other of the second S light and the second P light.

[0015] In some embodiments, the first diffuse reflector and the second diffuse reflector can be arranged on the same optical path and arranged sequentially according to the direction of the optical path, wherein the second S light and the second P light both propagate on the optical path.

[0016] In some embodiments, the first diffuse reflector and the second diffuse reflector can both be switchable between a first state and a second state, and in the case that the first diffuse reflector is in one of the first state and the second state, the second diffuse reflector is in the other state, wherein in the first state, the first diffuse reflector and the second diffuse reflector both transmit the second S light and the second P light, and in the second state, the first diffuse reflector images the one and absorbs the other, and the second diffuse reflector images the other and absorbs the one.

[0017] In some embodiments, the first diffuse reflector and the second diffuse reflector can both be tunable light polarization absorption films, which are switchable between the first state and the second state by adjustment of voltage.

[0018] In some embodiments, the first diffuse reflector can be configured to image the one and transmit the other, and the second diffuse reflector can be configured to image the other and transmit the one.

[0019] In some embodiments, a first internal mirror can also be included, which is disposed on the optical path between the first diffuse reflector and the first beamsplitter to reflect the second S light and the second P light to the first diffuse reflector.

[0020] In some embodiments, the first display device and the second display device can both be silicon-based liquid crystal display devices.

[0021] In some embodiments, a projection device can be further included, disposed on the optical path between the first beam splitter and the first diffuse reflector and the second diffuse reflector, for magnifying the second S light and the second P light exiting from the first beam splitter.

[0022] In some embodiments, a second beam splitter, a second internal mirror, a third internal mirror and a combiner can be further included, the second beam splitter disposed downstream of the optical path of the first beam splitter, for reflecting the second S light and transmitting the second P light; the second internal mirror disposed to receive the second S light from the second beam splitter and reflect it to the combiner; the third internal mirror disposed to receive the second P light from the second beam splitter and reflect it to the combiner; and the combiner for reflecting the second S light and transmitting the second P light.

[0023] Wherein the first diffuse reflector is arranged on the first optical path of the second S light between the second beam splitter and the combiner and images the second S light, and the second diffuse reflector is arranged on the second optical path of the second P light between the second beam splitter and the combiner and images the second P light.

[0024] In some embodiments, the first diffuse reflector can be arranged on the first optical path between the combiner and the second internal mirror, and the second diffuse reflector can be arranged on the second optical path between the combiner and the third internal mirror.

[0025] In some embodiments, the first diffuse reflector can be arranged on the first optical path between the second internal mirror and the second beam splitter, and the second diffuse reflector can be arranged on the second optical path between the combiner and the third internal mirror.

[0026] In some embodiments, the first diffuse reflector can be arranged on the first optical path between the combiner and the second internal mirror, and the second diffuse reflector can be arranged on the second optical path between the third internal mirror and the second beam splitter.

[0027] In some embodiments, the first diffuse reflector can be arranged on the first optical path between the second internal mirror and the second beam splitter, and the second diffuse reflector can be arranged on the second optical path between the third internal mirror and the second beam splitter.

[0028] According to another aspect of the present disclosure, a HUD device is also provided, comprising the PGU according to any of the above embodiments.

[0029] According to the above technical solution, by setting only one PGU in the HUD device and without setting an additional reflector, the HUD device has a small size. Furthermore, by using two LCOS display devices in the PGU to utilize both S-rays and P-rays from a single illumination device to form two virtual images, the HUD device has low power consumption. In addition, by setting two diffusers in the PGU to provide two effective display areas respectively, the HUD device can provide virtual images with a wider field of view. Attached Figure Description

[0030] The features and advantages of embodiments of the present disclosure will become more readily understood from the following description with reference to the accompanying drawings. The drawings are not drawn to scale and some features may be enlarged or reduced to show details of specific components. In the drawings:

[0031] Figure 1 This is a schematic diagram of the structure of a HUD system that includes HUD devices with related technologies.

[0032] Figure 2 This is a schematic diagram of the structure of a HUD system that includes another related technology.

[0033] Figure 3 This is a schematic diagram of the structure of a HUD system that includes another related technology.

[0034] Figure 4a and Figure 4b All of these are schematic diagrams of the PGU structure according to the first embodiment of this disclosure.

[0035] Figure 5 For including having Figure 4a and Figure 4b A schematic diagram of the HUD system of the PGU HUD device.

[0036] Figure 6 This is a schematic diagram of the structure of the PGU according to the second embodiment of the present disclosure.

[0037] Figure 7 For including having Figure 6 A schematic diagram of the HUD system of the PGU HUD device.

[0038] Figure 8 This is a schematic diagram of the structure of the PGU according to the third embodiment of the present disclosure.

[0039] Figure 9 For including having Figure 8 A schematic diagram of the HUD system of the PGU HUD device.

[0040] Figure 10A structural schematic diagram of a PGU according to a fourth embodiment of the present disclosure.

[0041] Figure 11 A structural schematic diagram of a HUD system including a PGU having Figure 10 A structural schematic diagram of a HUD system including a PGU having

[0042] Figure 12 A structural schematic diagram of a PGU according to a fifth embodiment of the present disclosure.

[0043] Figure 13 A structural schematic diagram of a PGU according to a sixth embodiment of the present disclosure.

[0044] Figure 14 A structural schematic diagram of a HUD device according to an embodiment of the present disclosure.

[0045] In the drawings, the same or corresponding technical features or components are denoted by the same or corresponding reference numerals. DETAILED DESCRIPTION

[0046] The present disclosure will be described in detail below with reference to the accompanying drawings and by way of exemplary embodiments. It is to be noted that the following detailed description of the present disclosure is merely for illustrative purposes and by no means limiting to the present disclosure.

[0047] It should be noted that, for the sake of clarity, not all features of a specific embodiment are described and shown in the specification and drawings, and in order to avoid obscuring the technical solutions of the present disclosure with unnecessary details, only the device structures closely related to the technical solutions of the present disclosure are described and shown in the specification and drawings, and other details which are not closely related to the technical content of the present disclosure and are known to those skilled in the art are omitted.

[0048] Below, reference Figures 1 to 3 A dual-focal-plane HUD device using an LCOS PGU under the prior architecture is described.

[0049] First, reference Figure 1 which shows a related-art HUD device 10' (schematically shown in a dashed-line frame), and shows a HUD system 1' including the HUD device 10' and an imaging reflection part 11'.

[0050] The HUD device 10' includes a PGU 100', a PGU 101', a mirror 200', and a beam splitter 300', wherein both the PGU 100' and the PGU 101' use LCOS.

[0051] Since LCOS is a reflective polarization device, the image light emitted by the PGU using LCOS is P-polarized light (abbreviated as P light) or S-polarized light (abbreviated as S light). In the HUD device 10', the PGU 100' and the PGU 101' are arranged in a manner that the image light emitted by the PGU 100' and the image light emitted by the PGU 101' are incident on the mirror 200' in a same direction.Figure 1 In the diagram, the image ray S1' (shown as a solid line) emitted by PGU100' is an S-ray, while the image ray S2' (shown as a dashed line) emitted by PGU101' is a P-ray.

[0052] Beam splitter 300' and mirror 200' are arranged opposite to each other. Beam splitter 300' is configured to reflect S-rays and transmit P-rays. PGU100' and PGU101' are respectively arranged on opposite sides of beam splitter 300'. PGU100' is arranged such that image light S1' emitted from PGU100' is reflected by beam splitter 300' to mirror 200', then reflected by mirror 200' to imaging reflector 11', and finally reflected by imaging reflector 11' to eye box 3'. Thus, on the outside of imaging reflector 11' (i.e., ... Figure 1 The first virtual image 4' is formed on the right side of the imaging reflector 11' and on the rearward extension line of the reflected image ray S1'. The PGU101' is arranged such that the image ray S2' emitted from the PGU101' passes through the beam splitter 300' and enters the reflector 200', is reflected by the reflector 200' to the imaging reflector 11', and is finally reflected by the imaging reflector 11' to the eye box 3'. Thus, a second virtual image 5' is formed on the outside of the imaging reflector 11' and on the rearward extension line of the reflected image ray S2'.

[0053] In the HUD device 10' under this architecture, the use of two PGUs, namely PGU100' and PGU101', results in a large size of HUD device 10'; moreover, since each PGU is equipped with an illumination device for providing light, the use of two PGUs also causes a large power consumption.

[0054] Next, refer to Figure 2 It shows another related technology HUD device 10'' (shown schematically in dashed box), and shows a HUD system 1'' including HUD device 10'' and imaging reflector 11'.

[0055] HUD device 10'' includes PGU100'', PGU101'', a first reflector 210'', a second reflector 220'' and a third reflector 230'', wherein PGU100'' and PGU101'' both use LCOS.

[0056] exist Figure 2 In the image ray S1'' emitted by PGU100'' (shown as a solid line) can be either an S-ray or a P-ray, and the image ray S2'' emitted by PGU101'' (shown as a dashed line) can also be either an S-ray or a P-ray.

[0057] The first reflecting mirror 210'' and the second reflecting mirror 220'' are both arranged opposite to the third reflecting mirror 230''. PGU100'' is arranged to emit image light rays S1'' towards the first reflecting mirror 210''. The image light rays S1'' are reflected by the first reflecting mirror 210'' to the third reflecting mirror 230'', then by the third reflecting mirror 230'' to the imaging reflecting unit 11', and finally by the imaging reflecting unit 11' to the eyepiece 3', thereby forming the first virtual image 4''. PGU101'' is arranged to emit image light rays S2'' towards the second reflecting mirror 220''. The image light rays S2'' are reflected by the second reflecting mirror 220'' to the third reflecting mirror 230'', then by the third reflecting mirror 230'' to the imaging reflecting unit 11', and finally by the imaging reflecting unit 11' to the eyepiece 3', thereby forming the second virtual image 5''.

[0058] In the HUD device 10'' under this architecture, the size of the HUD device 10'' is large due to the use of two PGUs, namely PGU100'' and PGU101'', and the use of more reflectors; moreover, the use of two PGUs also results in greater power consumption because each PGU is equipped with an illumination device.

[0059] Next, refer to Figure 3 It shows another related technology HUD device 10''', and shows a HUD system 1''' including HUD device 10''' and imaging reflector 11'.

[0060] HUD device 10''' includes PGU100''', first reflector 210''', second reflector 220''', and beam splitter 300''', wherein PGU100''' uses LCOS.

[0061] exist Figure 3 In the display area, the PGU100 emits image rays S1''' (shown as solid lines) and S2''' (shown as dashed lines) in two regions. Image ray S1''' is a P-ray, while image ray S2''' is an S-ray.

[0062] The first mirror 210''' and the beam splitter 300''' are arranged opposite to the second mirror 220''', and the beam splitter 300''' is arranged between the first mirror 210''' and the second mirror 220'''. The beam splitter 300''' is configured to reflect S light and transmit P light. The PGU 100''' is arranged such that the image light ray S1''' exiting from the PGU 100''' is reflected via the first mirror 210''' to the beam splitter 300''', is transmitted through the beam splitter 300''' to be incident to the second mirror 220''', is reflected via the second mirror 220''' to the imaging reflecting part 11', and is finally reflected via the imaging reflecting part 11' to the eye box 3', thereby forming the first virtual image 4'''. While the image light ray S2''' exiting from the PGU 100''' is reflected via the beam splitter 300''' to the second mirror 220''', is reflected via the second mirror 220''' to the imaging reflecting part 11', and is finally reflected via the imaging reflecting part 11' to the eye box 3', thereby forming the second virtual image 5'''.

[0063] In the HUD device 10''' under this architecture, although the volume and power consumption of the HUD device 10''' are not increased due to the use of only 1 PGU and 2 mirrors, the size of each of the two virtual images formed is reduced, i.e., the field of view of the virtual image is reduced, because the image light ray S1''' corresponding to the first virtual image 4''' and the image light ray S2''' corresponding to the second virtual image 5''' are emitted from two display regions respectively divided from the effective display region of the PGU.

[0064] The above problem can be solved by the PGU according to the embodiments of the present disclosure. Hereinafter, the PGU according to the embodiments of the present disclosure will be described with reference to Figures 4a to 13 The PGU according to the embodiments of the present disclosure will be described.

[0065] Figure 4a , Figure 4b , Figure 6 , Figure 8 , Figure 10 , Figure 12 and Figure 13 respectively show a PGU 100 (shown in a dashed line box in these figures) according to the embodiments of the present disclosure, Figure 5 , Figure 7 , Figure 9 and Figure 11 respectively show a HUD system 1 including a HUD device 10 (shown in a dashed line box in these figures) having the PGU 100 and an imaging reflecting part 11.

[0066] The PGU 100 comprises an illuminating device 110, a first light splitting mirror 120, a first display device 130, a second display device 140, a projecting device 150, a first diffuse reflector 160 and a second diffuse reflector 170.

[0067] The illuminating device 110 is configured to provide light rays S for forming image light rays S1 out of the PGU 100 from the light rays S. Exemplarily, the illuminating device 110 can comprise a light source for providing the light rays, a collimating system for collimating the light rays, a homogenizing system for homogenizing the light rays, a relay system and the like. The light rays S comprise both S light and P light, for example, the light rays S can be natural light provided by a LED light source.

[0068] The first light splitting mirror 120 is disposed on the light exit side of the illuminating device 110 for reflecting S light (hereinafter referred to as first S light) S11 from the light rays S of the illuminating device 110 and transmitting P light (hereinafter referred to as first P light) S12 from the light rays S. Thus, by light splitting of the first light splitting mirror 120, the light rays S form two light rays, i.e. the first S light S11 and the first P light S12. The first light splitting mirror 120 can be, for example, a light splitting prism which is glued by two triangular prisms, and the glued surface is provided with a film for reflecting S light and transmitting P light. It can be envisaged that other surfaces of the light splitting prism are provided with anti-reflection film for improving light transmittance, thereby improving light efficiency.

[0069] The first display device 130 and the second display device 140 are both LCOS display devices.

[0070] The first display device 130 is configured to receive the first S light S11 from the first light splitting mirror 120 for converting the first S light S11 into P light (hereinafter referred to as second P light) S21 and reflecting the second P light S21 to the first light splitting mirror 120. Since the first light splitting mirror 120 transmits P light, the second P light S21 will transmit through the first light splitting mirror 120.

[0071] The second display device 140 is configured to receive the first P light S12 from the first light splitting mirror 120 for converting the first P light S12 into S light (hereinafter referred to as second S light) S22 and reflecting the second S light S22 to the first light splitting mirror 120. Since the first light splitting mirror 120 reflects S light, the second S light S22 will be reflected by the first light splitting mirror 120.

[0072] The projecting device 150 is disposed on the light path between the first light splitting mirror 120 and the first diffuse reflector 160 and the second diffuse reflector 170. Exemplarily, in the PGU 100, the projecting device 150 is disposed on the light path between the first light splitting mirror 120 and the first diffuse reflector 160. Figure 4a and Figure 4bIn this case, the projection device 150 is disposed on the optical path between the first beam splitter 120 and the first diffuse reflector 160. The projection device 150 may, for example, be composed of a lens group for magnifying the second P light S21 and the second S light S22 that exit from the first beam splitter 120.

[0073] The first diffuse reflector 160 and the second diffuse reflector 170 are each disposed downstream of the optical path of the first beam splitter 120, specifically, as shown in Figure 4a and Figure 4b indicated in the above, downstream of the optical path of the projection device 150, to provide two effective display regions, respectively.

[0074] The first diffuse reflector 160 is configured to image one of the second S light S22 and the second P light S21, and the second diffuse reflector 170 is configured to image the other of the second S light S22 and the second P light S21. For example, in Figure 4a and Figure 4b , the first diffuse reflector 160 is configured to image the second P light S21 to provide an effective display region for the second P light S21; and the second diffuse reflector 170 is configured to image the second S light S22 to provide another effective display region for the second S light S22.

[0075] In this case, for example, referring to Figure 5 , the image light rays S1 that exit from the PGU 100, i.e., the second P light S21 (indicated by a horizontal line to indicate the polarization direction thereof) and the second S light S22 (indicated by a dot to indicate the polarization direction thereof, which is orthogonal to the polarization direction of the second P light S21), are reflected via the first mirror 210 to the second mirror 220, and are reflected via the second mirror 220 to the reflective imaging portion 11, and are further reflected via the reflective imaging portion 11 to the eyebox 3, thereby forming the first virtual image 4 and the second virtual image 5, respectively. That is, with the HUD device 10, virtual images at two different distances can be obtained.

[0076] In this way, the volume of the HUD device 10 is smaller than that of the HUD devices 10' and 10" in the prior art, which are provided with two PGUs and more mirrors, since the HUD device 10 is provided with only one PGU, i.e., the PGU 100, and is not provided with additional mirrors. Moreover, the power consumption of the HUD device 10 is smaller than that of the HUD devices 10' and 10" in the prior art, which are provided with two PGUs and more mirrors, since the HUD device 10 is provided with only one PGU, which utilizes both S light and P light from one illumination device by using two LCOS display devices to form two virtual images, compared with the HUD devices 10' and 10" in the prior art, which respectively use only one polarization light, e.g., S light or P light, of the light from two illumination devices to form two virtual images. Furthermore, the HUD device 10 is able to provide virtual images with a larger field of view than the HUD device 10'" in the prior art, which is provided with one effective display area to provide two display areas by splitting the one effective display area into two, since the HUD device 10 provides two effective display areas by two diffuse reflectors in the PGU 100, respectively.

[0077] It should be noted that the focusing of the second P light S21 on the first diffuse reflector 160 and the focusing of the second S light S22 on the second diffuse reflector 170 are achieved by adjusting the first optical back focal length and the second optical back focal length, respectively. The first optical back focal length is the distance between the first display device 130 and the first beam splitter 120, and the second optical back focal length is the distance between the second display device 140 and the first beam splitter 120.

[0078] In some embodiments, as shown in Figure 4a , Figure 4b and Figure 6 , the first diffuse reflector 160 and the second diffuse reflector 170 are arranged on the same light path and are sequentially arranged according to the direction of the light path, wherein the second S light S22 and the second P light S21 both propagate on the light path.

[0079] As shown in Figure 4a , Figure 4b and Figure 6 , the light path is the light path of the second S light S22, and is also the light path of the second P light S21, i.e., the second S light S22 and the second P light S21 are in the same light path. By sequentially arranging the first diffuse reflector 160 and the second diffuse reflector 170 on the light path according to the direction of the light path, the first diffuse reflector 160 is closer to the first beam splitter 120, or closer to the projection device 150, than the second diffuse reflector 170.

[0080] In this way, the second P light S21 and the second S light S22 can be directly projected to the first mirror 210 after being imaged on the first diffuse reflector 160 and the second diffuse reflector 170, respectively, without the need to provide other optical elements. Thereby, the internal structure of the PGU 100 is simplified.

[0081] In some embodiments, with reference to Figure 4a 、 Figure 4b and Figure 5 , the first diffuse reflector 160 and the second diffuse reflector 170 are each switchable between a first state and a second state, and in the case where the first diffuse reflector 160 is in one of the first state and the second state, the second diffuse reflector 170 is in the other state. In the first state, the first diffuse reflector 160 and the second diffuse reflector 170 each transmit the second S light and the second P light, and in the second state, the first diffuse reflector 160 images one of the second S light S22 and the second P light S21 and absorbs the other, while the second diffuse reflector 170 images the other and absorbs the one.

[0082] For example, as shown in Figure 4a and Figure 4b , the first diffuse reflector 160 images the second P light S21 and absorbs the second S light S22 in the second state, while the second diffuse reflector 170 images the second S light S22 and absorbs the second P light S21 in the second state.

[0083] In this case, with reference to Figure 4a , when the first diffuse reflector 160 is set to be in the first state, the second diffuse reflector 170 is set to be in the second state. At this time, when the second S light S22 and the second P light S21 from the projection device 150 are incident to the first diffuse reflector 160, the second S light S22 and the second P light S21 each transmit through the first diffuse reflector 160 and are incident to the second diffuse reflector 170. Thereby, the second S light S22 is imaged on the second diffuse reflector 170, and the second P light S21 is absorbed by the second diffuse reflector 170. The imaged second S light S22 is projected to the first mirror 210 and reaches the eyebox 3 after being reflected by the first mirror 210, the second mirror 220, and the reflection imaging portion 11 in this order, thereby forming the second virtual image 5.

[0084] On the other hand, with reference to Figure 4bWhen the first diffuse reflector 160 is set to be in the second state, the second diffuse reflector 170 is set to be in the first state. At this time, when the second S light S22 and the second P light S21 from the projection device 150 are incident to the first diffuse reflector 160, the second P light S21 is imaged on the first diffuse reflector 160, and the second S light S22 is absorbed by the first diffuse reflector 160. The imaged second P light S21 is projected to the first mirror 210 through the second diffuse reflector 170, and reaches the eyebox 3 after being reflected by the first mirror 210, the second mirror 220, and the reflection imaging portion 11 in this order, thereby forming the first virtual image 4.

[0085] In this way, the double virtual image display can be realized by switching between the first state and the second state, and the switching between the close-range virtual image and the long-range virtual image can be performed according to the different time sequences of the scenes in actual use, thereby providing a better visual experience.

[0086] In some embodiments, the first diffuse reflector 160 and the second diffuse reflector 170 can each be a tunable light polarization absorption film that is switched between the first state and the second state by adjustment of voltage. At this time, the first state is a transparent state assumed by the tunable light polarization absorption film in an energized state, and the second state is a fogging state assumed by the tunable light polarization absorption film in a de-energized state.

[0087] In some embodiments, referring to Figure 6 and Figure 7 , the first diffuse reflector 160 can be configured to image one of the second S light S22 and the second P light S21 and transmit the other, and the second diffuse reflector 170 can be configured to image the other of the second S light S22 and the second P light S21 and transmit the above one.

[0088] At this time, the first diffuse reflector 160 and the second diffuse reflector 170 are each a polarization-type diffuse reflector. For example, as shown in Figure 6 , the first diffuse reflector 160 can be configured to image the second P light S21 and transmit the second S light S22, and the second diffuse reflector 170 is configured to image the second S light S22 and transmit the second P light S21.

[0089] In this case, when the second S light S22 and the second P light S21 from the projection device 150 are incident to the first diffuse reflector 160, the second P light S21 is imaged on the first diffuse reflector 160 and is projected to the first mirror 210 through the second diffuse reflector 170; the second S light S22 is imaged on the second diffuse reflector 170 by passing through the first diffuse reflector 160 and is projected to the first mirror 210. In this way, the second P light S21 and the second S light S22 reach the eyebox 3 by being reflected in turn via the first mirror 210, the second mirror 220, the reflection imaging portion 11, thereby forming the first virtual image 4 and the second virtual image 5, respectively.

[0090] In this way, the first virtual image 4 and the second virtual image 5 can be formed simultaneously, so that the user can observe the two virtual images at the same time.

[0091] In some embodiments, with reference to Figure 4a , Figure 4b and Figure 6 , the PGU 100 can further include a first internal mirror 180, which is disposed on the optical path between the first diffuse reflector 160 and the first beam splitter 120, specifically, between the first diffuse reflector 160 and the projection device 150, to reflect the second S light S22 and the second P light S21 exiting from the projection device 150 to the first diffuse reflector 160.

[0092] By disposing the first internal mirror 180, the positions of the optical elements within the PGU 100 can be adjusted so as to make the PGU 100, and thus the HUD device 10, have a smaller volume.

[0093] In some embodiments, with reference to Figures 8 to 13 , the PGU 100 can include a second beam splitter 121, a second internal mirror 181, a third internal mirror 182 and a combining mirror 190.

[0094] The second beam splitter 121 is disposed downstream of the first beam splitter 120, specifically, downstream of the projection device 150, for reflecting the second S light S22 and transmitting the second P light S21. The second internal mirror 181 is disposed to receive the second S light S22 from the second beam splitter 121, i.e., to receive the second S light S22 reflected via the second beam splitter 121, and to reflect the second S light S22 to the combining mirror 190. The third internal mirror 182 is disposed to receive the second P light S21 from the second beam splitter 121, i.e., to receive the second P light S21 transmitted through the second beam splitter 121, and to reflect the second P light S21 to the combining mirror 190. The combining mirror 190 is configured to reflect the second S light S22 and transmit the second P light S21.

[0095] In this way, by the light splitting by the second light-splitter 121, the second S light S22 and the second P light S21 start to propagate along different optical paths, and thereafter, by the light combination by the light combiner 190, the second S light S22 and the second P light S21, which have been propagating along different optical paths, start to propagate along the same optical path again.

[0096] In the present embodiment, the first diffuse reflector 160 is arranged on the first optical path S100 of the second S light S22 between the second light-splitter 121 and the light combiner 190 and images the second S light S22, and the second diffuse reflector 170 is arranged on the second optical path S200 of the second P light S21 between the second light-splitter 121 and the light combiner 190 and images the second P light S21.

[0097] Thereby, when the second S light S22 and the second P light S21 from the projection device 150 are incident to the second light-splitter 121, the second S light S22 propagates on the first optical path S100 by reflection by the second light-splitter 121 to be imaged on the first diffuse reflector 160 and projected to the light combiner 190, and the second P light S21 propagates on the second optical path S200 by transmission through the second light-splitter 121 to be imaged on the second diffuse reflector 170 and projected to the light combiner 190. The light combiner 190 reflects the second S light S22 projected thereto and transmits the second P light S21 projected thereto. Thereby, for example, with reference to Figure 9 , the second S light S22 and the second P light S21 are projected to the first mirror 210 as image light rays S1 exiting from the PGU 100 and reach the eyebox 3 by reflection successively through the first mirror 210, the second mirror 220 and the reflecting imaging portion 11, thereby forming the first virtual image 4 and the second virtual image 5, respectively.

[0098] In this way, since the second S light S22 and the second P light S21 are imaged on the respective diffuse reflectors while being in different optical paths, there is no need to take into account the influence of one of the second S light S22 and the second P light S21 on the other one when imaging. For example, there is no need to specially use a specific type of diffuse reflector to eliminate such influence, such as the diffuse reflectors in Figure 4a , Figure 4b and Figure 6 . Moreover, the first virtual image 4 and the second virtual image 5 can be formed simultaneously, so that a user can observe both virtual images at the same time.

[0099] In some embodiments, with reference to Figure 8 , the first diffuse reflector 160 can be arranged on the first optical path S100 between the second internal mirror 181 and the second light-splitter 121, and the second diffuse reflector 170 can be arranged on the second optical path S200 between the light combiner 190 and the third internal mirror 182.

[0100] In this way, as shown in Fig. 2, the second S light S22 and the second P light S21 are imaged on the respective first and second diffuse reflectors 160, 170 while being in different optical paths.Figure 8 and Figure 9 As shown, the first diffuse reflector 160 is farther from the first reflector 210 at the reflecting end of the HUD device 10, while the second diffuse reflector 170 is closer to the first reflector 210 at the reflecting end of the HUD device 10, and the optical path difference between the two is relatively large. This arrangement is suitable for situations where the distance difference between the two formed virtual images is large, and the virtual image formed by the second S-beam S22 is farther away.

[0101] In some implementations, refer to Figure 10 The first diffuse reflector 160 can be arranged on the first optical path S100 between the beam combiner 190 and the second internal reflector 181, and the second diffuse reflector 170 can be arranged on the second optical path S200 between the third internal reflector 182 and the second beam splitter 121.

[0102] Therefore, referring to Figure 11 The second P-ray S21 and the second S-ray S22 are projected as image rays S1 emitted from PGU100 onto the first reflector 210, and are reflected sequentially by the first reflector 210, the second reflector 220 and the reflective imaging unit 11 to reach the eye box 3, thereby forming the first virtual image 4 and the second virtual image 5 respectively.

[0103] In this way, such as Figure 10 and Figure 11 As shown, the first diffuse reflector 160 is closer to the first reflecting mirror 210 at the reflecting end of the HUD device 10, while the second diffuse reflector 170 is farther from the first reflecting mirror 210 at the reflecting end of the HUD device 10, and the optical path difference between the two is large. This arrangement is suitable for situations where the distance difference between the two formed virtual images is large, and the virtual image formed by the second P-beam S21 is farther apart.

[0104] In some implementations, refer to Figure 12 The first diffuse reflector 160 can be arranged on the first optical path S100 between the beam combiner 190 and the second internal reflector 181, and the second diffuse reflector 170 can be arranged on the second optical path S200 between the beam combiner 190 and the third internal reflector 182.

[0105] In this arrangement, the first diffuse reflector 160 and the second diffuse reflector 170 are both close to the first reflecting mirror 210 at the reflecting end of the HUD device 10, and the optical path difference between them is small. Therefore, the optical path at the reflecting end of the HUD device 10 is short, the virtual image distance is close, and the distance difference between the two formed virtual images is small. This arrangement is suitable for situations where the distance difference between the two formed virtual images is small, and the virtual images are close together.

[0106] In some implementations, refer toFigure 13 The first diffuse reflector 160 can be arranged between the second internal mirror 181 and the second beam splitter 121 on the first light path S100, and the second diffuse reflector 170 can be arranged between the third internal mirror 182 and the second beam splitter 121 on the second light path S200.

[0107] In this way, the first diffuse reflector 160 and the second diffuse reflector 170 are both far away from the first mirror 210 of the reflection end of the HUD device 10, and the optical path difference of the two is small. Therefore, the reflection end optical path of the HUD device 10 is long, the virtual image distance is far, and the distance difference of the two virtual images formed is small. Such an arrangement is suitable for the case where the distance difference of the two virtual images formed is small, and the virtual image distance is far.

[0108] It should be noted that, in the case shown in Figure 12 and Figure 13 , since the difference between the optical path of the first diffuse reflector 160 from the first mirror 210 and the optical path of the second diffuse reflector 170 from the first mirror 210 is small, in actual operation, the corresponding optical path difference can be adjusted by adjusting the first diffuse reflector 160 and the second diffuse reflector 170 along the corresponding optical axis by a certain distance to obtain a corresponding different virtual image distance. Therefore, the corresponding light path diagram of the two virtual images formed will be similar to Figure 9 or Figure 11 , and therefore is not shown again.

[0109] According to another aspect of the present disclosure, as shown in Figure 14 , a HUD device 10 (shown in a dashed box) is also provided, which includes the above-mentioned PGU 100 (also shown in a dashed box).

[0110] In addition, the HUD device 10 can also include a reflection unit, for example, including the first mirror 210 and the second mirror 220, and the display light rays S1 emitted by the PGU 100 can be emitted from the HUD device 10 in turn via reflection of the first mirror 210 and the second mirror 220.

[0111] In the present disclosure, the use of the terms "first", "second" and the like is merely for the purpose of facilitating description and should not be regarded as limiting. In addition, although the present disclosure has been described with reference to exemplary embodiments, it should be understood that the present disclosure is not limited to the specific embodiments described and shown in detail. Those skilled in the art can make various changes to the exemplary embodiments without departing from the scope defined by the claims of the present disclosure.

[0112] The features mentioned and / or shown in the description of the example embodiments of the present disclosure can be combined in any manner with one or more other features mentioned and / or shown, and / or with features of other embodiments, without departing from the scope of the present disclosure. The technical solutions obtained by the combination of the features mentioned and / or shown in the description of the example embodiments of the present disclosure with one or more other features mentioned and / or shown, and / or with features of other embodiments, should also be considered as included in the scope of protection of the present disclosure.

Claims

1. An image generation unit characterized by comprising: Comprising: an illumination device for providing light rays; a first beam splitter arranged on an exit side of the illumination device for reflecting first S light and transmitting first P light among the light rays; a first display device arranged to receive the first S light from the first beam splitter for converting it into second P light and reflecting the second P light to the first beam splitter; a second display device arranged to receive the first P light from the first beam splitter for converting it into second S light and reflecting the second S light to the first beam splitter; a first diffuse reflector arranged downstream of the first beam splitter in an optical path of the first beam splitter and configured to image one of the second S light and the second P light; and a second diffuse reflector arranged downstream of the first beam splitter in the optical path of the first beam splitter and configured to image the other of the second S light and the second P light, the first and second diffuse reflectors being two separate diffuse reflectors, the first and second diffuse reflectors being arranged on the same optical path and sequentially arranged according to a direction of the optical path, wherein the second S light and the second P light both propagate on the optical path, the first and second diffuse reflectors are both switchable between a first state and a second state, and in a case where the first diffuse reflector is in one of the first state and the second state, the second diffuse reflector is in the other state, wherein in the first state, the first and second diffuse reflectors both transmit the second S light and the second P light, and in the second state, the first diffuse reflector images the one and absorbs the other, while the second diffuse reflector images the other and absorbs the one.

2. The image generation unit of claim 1, wherein, the first and second diffuse reflectors are both tunable optical polarization absorbing films, which are switched between the first state and the second state by adjustment of a voltage.

3. The image generation unit according to claim 1 or 2, characterized in that, Further comprising a first internal mirror arranged on the optical path between the first diffuse reflector and the first beam splitter for reflecting the second S light and the second P light to the first diffuse reflector.

4. The image generation unit according to claim 1 or 2, characterized in that, the first and second display devices are both liquid crystal on silicon display devices.

5. The image generation unit according to claim 1 or 2, characterized by Further comprising a projection device arranged on the optical path between the first beam splitter and the first and second diffuse reflectors for magnifying the second S light and the second P light exiting from the first beam splitter.

6. A head-up display device, characterized by comprising an image generation unit according to any one of claims 1 to 5.

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