Vehicle-mounted imaging equipment

Abstract

The invention discloses vehicle-mounted imaging equipment which comprises an image source, a first lens, a second lens, a first curved mirror and a second curved mirror. Image light rays emitted by the image source firstly enter the first lens and then enter the second lens through reflection of the first lens, the second lens reflects the incident light rays to the first curved mirror, the incident light rays are reflected to the second curved mirror through the first curved mirror, and then the incident light rays are reflected to the position of a passenger through the second curved mirror. The emergent surface of the second lens serves as an object surface, and the first curved mirror and the second curved mirror are used for imaging the image light emitted by the second lens, so that a large-size virtual screen is formed at a set position in front of a passenger. The device is not limited by the space in the vehicle any more, passengers can watch large-size images at a comfortable watching distance, the adjusting force of ciliary muscles of human eyes is not changed at the moment, asthenopia can be reduced, and the carsickness phenomenon caused by watching a screen at a short distance is relieved.

Description

Technical Field

[0001] The present invention relates to the field of display technology, and in particular to a vehicle-mounted imaging device. Background Art

[0002] With the development of automobile intelligence, more and more smart cars tend to install more and larger in-vehicle screens. However, whether the screen is hung on the back of the front seat or on the roof of the vehicle, a large space is required in the car, so the in-vehicle screen is generally used in medium and large models such as business and executive vehicles.

[0003] However, even for medium and large cars with excellent space performance, the size of the in-car screen cannot be infinitely expanded. On the other hand, considering the limited viewing distance in the car, it is not suitable to install a large-sized display screen. A large-sized display screen will take up a lot of space in the car, and watching the screen at a close distance while driving will cause visual fatigue, motion sickness and other problems, affecting the viewing experience. Summary of the invention

[0004] An embodiment of the present invention provides a vehicle-mounted imaging device, including:

[0005] An image source, used for emitting image light;

[0006] A first lens is located at the light-emitting side of the image source; the first lens receives and reflects the emitted light from the image source;

[0007] A second lens is located on the path of the reflected light of the first lens; the second lens is used to change the divergence angle of the incident light and reflect it;

[0008] Two curved mirrors, namely a first curved mirror and a second curved mirror, the first curved mirror is located on the path of the reflected light of the second lens, and the second curved mirror is located on the path of the reflected light of the first curved mirror; the first curved mirror receives the light reflected by the second lens and reflects it toward the second curved mirror, and the second curved mirror receives the light reflected by the first curved mirror and reflects it toward the position of the passenger, and the first curved mirror and the second curved mirror are used to image the incident light beam at a set position in front of the passenger.

[0009] In some embodiments of the present invention, the first lens is a plane reflector.

[0010] In some embodiments of the present invention, the first curved mirror is a convex reflector, and the second curved mirror is a concave reflector;

[0011] In some embodiments of the present invention, the surface shapes of the first curved mirror and the second curved mirror are both free-form surfaces.

[0012] In some embodiments of the present invention, the surface shapes of the first curved mirror and the second curved mirror satisfy:

[0013]

[0014] Wherein, z represents the surface equation of the first curved mirror or the second curved mirror, c represents the curvature, k represents the cone coefficient, r represents the radial coordinate, N represents the number of terms of the extended polynomial, and A i represents the coefficient of the i-th expanded polynomial.

[0015] In some embodiments of the present invention, the image source is a laser projection device, and the laser projection device emits three-color lasers.

[0016] In some embodiments of the present invention, a reflection-enhancing film is provided on the reflective surface of the second curved mirror, and the reflection-enhancing film is used to reflect light of corresponding wavelength bands of the three-color laser emitted by the laser projection device and absorb light of other wavelength bands.

[0017] In some embodiments of the present invention, an adjustment portion is provided on a side of the first curved mirror facing away from the second curved mirror, and the adjustment portion is used to adjust the pitch angle of the first curved mirror to adjust the imaging height.

[0018] In some embodiments of the present invention, the distance between the imaging device on board and the passenger is 3m to 4m;

[0019] The image size viewed by passengers is 20 inches to 50 inches.

[0020] In some embodiments of the present invention, the size of the vehicle-mounted imaging device is less than or equal to 75 mm×200 mm×200 mm, and the vehicle-mounted imaging device is installed in the backrest of the front seat of the vehicle.

[0021] The vehicle-mounted imaging device provided by the embodiment of the present invention includes: an image source, a first lens, a second lens, a first curved mirror and a second curved mirror. The image light emitted by the image source is first incident on the first lens and then reflected by the first lens to the second lens. The second lens reflects the incident light to the first curved mirror, which is then reflected to the second curved mirror by the first curved mirror, and then reflected to the passenger's position by the second curved mirror. The exit surface of the second lens serves as the object surface, and the first curved mirror and the second curved mirror are used to image the image light emitted by the second lens, thereby forming a large-sized virtual screen at a set position in front of the passenger. No longer constrained by the space inside the vehicle, passengers can view large-sized images at a comfortable viewing distance. At this time, the adjustment force of the ciliary muscles of the human eye remains unchanged, which can reduce visual fatigue and alleviate motion sickness caused by watching the screen at a close distance. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings introduced below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0023] Figure 1 One of the structural schematic diagrams of the vehicle-mounted imaging device provided by an embodiment of the present invention;

[0024] Figure 2 A schematic diagram of imaging of a vehicle-mounted imaging device provided by an embodiment of the present invention;

[0025] Figure 3 A schematic diagram of the positional relationship of the vehicle-mounted imaging device provided in an embodiment of the present invention;

[0026] Figure 4 A second structural diagram of a vehicle-mounted imaging device provided by an embodiment of the present invention;

[0027] Figure 5 A third structural diagram of a vehicle-mounted imaging device provided by an embodiment of the present invention;

[0028] Figure 6 A point diagram of a vehicle-mounted imaging device provided by an embodiment of the present invention;

[0029] Figure 7 An optical transfer function curve diagram of a vehicle-mounted imaging device provided by an embodiment of the present invention;

[0030] Figure 8 A TV distortion diagram of a vehicle-mounted imaging device provided by an embodiment of the present invention;

[0031] Fig. 9 A parallax angle distribution curve in the horizontal direction of the vehicle-mounted imaging device provided by an embodiment of the present invention;

[0032] Fig.10 This is a parallax angle distribution curve in the vertical direction of the vehicle-mounted imaging device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described below with reference to the accompanying drawings and examples. However, the exemplary embodiments can be implemented in various forms and should not be understood as being limited to the embodiments described herein; on the contrary, these embodiments are provided to make the present invention more comprehensive and complete, and to fully convey the concepts of the exemplary embodiments to those skilled in the art. The same figure marks in the figures represent the same or similar structures, and thus their repeated descriptions will be omitted. The words expressing position and direction described in the present invention are all explained using the accompanying drawings as examples, but changes can be made as needed, and the changes made are all included in the scope of protection of the present invention. The drawings of the present invention are only used to illustrate the relative position relationship and do not represent the true proportions.

[0034] With the development of automobile intelligence, more and more smart cars tend to install more and larger in-vehicle display screens. Currently, the display screens used for in-vehicle display can be divided into two types: projection display and direct display.

[0035] Projection display is usually used in head-up display. The image is displayed by the display device. After the projection lens forms an image, the projection light is projected onto the windshield of the vehicle. The windshield reflects the light to the human eye so that the virtual image can be seen directly in front of the vehicle. Direct display can usually use the currently mature liquid crystal display or organic light-emitting diode display to directly emit light to the human eye so that the display image can be seen.

[0036] However, since projection display requires the use of a windshield to reflect light, this type of display is usually only applicable to the driver's and co-pilot's seats, but there is no windshield for the rear passengers, so imaging of the rear passengers is impossible.

[0037] Whether the large-size display screen is hung on the back of the front seat or on the roof of the vehicle, it requires a large space in the car, so it can generally only be used in medium and large models such as business and executive vehicles. However, even for medium and large vehicles with excellent space performance, the size of the on-board screen cannot be infinitely expanded. On the other hand, in terms of the limited viewing distance in the car, it is not suitable to install a large-size display screen. A large-size display screen will take up a lot of space in the car, and watching the screen at a close distance while driving will cause visual fatigue, motion sickness and other problems, affecting the viewing experience.

[0038] In view of this, an embodiment of the present invention provides a vehicle-mounted imaging device that can occupy a relatively small space to image and display a large-size image.

[0039] Figure 1 This is one of the structural schematic diagrams of the vehicle-mounted imaging device provided in an embodiment of the present invention.

[0040] like Figure 1 As shown, the vehicle-mounted imaging device provided by the embodiment of the present invention includes: an image source 10, a first lens 20, a second lens 30 and two curved mirrors, namely a first curved mirror 40 and a second curved mirror 50.

[0041] Among them, the first lens 20 is located on the light output side of the image source 10, the second lens 30 is located on the path of the reflected light of the first lens 20, the first curved mirror 40 is located on the path of the reflected light of the second lens 30, and the second curved mirror 50 is located on the path of the reflected light of the first curved mirror 40.

[0042] The image light emitted by the image source 10 is first incident on the first lens 20 and then reflected by the first lens 20 to the second lens 30. The second lens 30 can adopt a reflective diffuser to reflect the incident light 30 to the first curved mirror 40, and then reflected by the first curved mirror 40 to the second curved mirror 50, and then reflected by the second curved mirror 50 to the passenger's position.

[0043] like Figure 1 As shown, the vehicle-mounted imaging device provided by the embodiment of the present invention adopts an off-axis reflective optical system and folds the optical path multiple times, which is beneficial to reducing the volume of the imaging device. The volume of the vehicle-mounted imaging device can be reduced to less than 75mm×200mm×200mm, so that the imaging device can be installed in the backrest of the front seat of the vehicle without occupying the space inside the vehicle.

[0044] The light emitted by the image source 10 first enters the first lens 20. The main function of the first lens 20 is to fold the light path. Therefore, in a specific implementation, the first lens 20 can be a plane reflector to reflect the incident light of the full band.

[0045] The second lens 30 is a reflective diffuser. In the vehicle-mounted imaging device provided by the embodiment of the present invention, the diffuser serves as the object surface of the optical system, and its light receiving surface can be provided with a microstructure, and the surface away from the microstructure is silver-plated for reflecting light. The microstructure can make the diffusion angle of the outgoing light match the field of view of the optical system and increase the system light efficiency.

[0046] The first curved mirror 40 and the second curved mirror 50 not only have the function of reflecting light, but also are used to image the image light emitted by the second lens 30. In the embodiment of the present invention, the first curved mirror 40 and the second curved mirror 50 are designed to form a virtual image of the incident light at a set position in front of the passenger, thereby forming a large-sized virtual screen in front of the passenger. In the specific implementation, the distance between the virtual screen formed by the vehicle-mounted imaging device and the passenger is 3m to 4m, and the size of the virtual screen viewed by the passenger is 20 inches to 40 inches, which is equivalent to the passenger being able to view a 20-inch to 40-inch image at a position 3m to 4m in front of the passenger. As a result, the imaging device is no longer restricted to the space inside the vehicle, and the passenger can view a large-sized image at a comfortable viewing distance. At this time, the adjustment force of the ciliary muscle of the human eye remains unchanged, which can reduce visual fatigue and alleviate motion sickness caused by viewing the screen at a close distance.

[0047] It should be pointed out that in the field of in-vehicle display, the factors affecting the user's motion sickness can be reflected in many aspects, such as the factors affecting the motion sickness may include: imaging distance, the graininess of the display screen, the contrast of the display image, and whether the display image flickers, etc. Usually, a smaller imaging distance, more obvious graininess of the display screen, lower contrast of the display image, and more severe flickering of the display image will aggravate the user's motion sickness. In order to improve the user's motion sickness, the above factors can be taken into consideration when designing in-vehicle imaging equipment.

[0048] In the embodiment of the present invention, the distance between the imaging device and the passenger needs to be designed to be within the user's comfortable viewing distance, and the imaging has a larger size. In addition, the optimization of imaging parameters such as resolution and contrast needs to be considered.

[0049] Specifically, the vehicle-mounted imaging device provided by the embodiment of the present invention needs to optimize optical parameters such as the distance between the second lens 30 and the first curved mirror 40, the distance between the first curved mirror 40 and the second curved mirror 50, the relative angle between the first curved mirror 40 and the second lens 30, the relative angle between the second curved mirror 50 and the first curved mirror 40, and the surface shape of the first curved mirror 40 and the second curved mirror 50 according to requirements such as virtual image distance, eye point distance, field of view, resolution, virtual image size, object distance, image distance, magnification, and imaging device size.

[0050] In the embodiment of the present invention, the design principle of the vehicle-mounted imaging device is specifically described with the virtual image distance of 4m and the virtual image size of 40 inches combined with the limitations of parameters such as the in-vehicle space and the display effect. Figure 2 This is a schematic diagram of imaging of a vehicle-mounted imaging device provided by an embodiment of the present invention. Figure 3 A schematic diagram of the positional relationship of the vehicle-mounted imaging devices provided in an embodiment of the present invention.

[0051] The on-board imaging device is installed in the backrest of the front seat of the vehicle, and the rear passengers can watch the 40-degree display image at a distance of 4m. Figure 2 and Figure 3 As shown, if the position of the passenger is Q and the position of the virtual image is P, the position between the passenger and the virtual image is the virtual image distance st, the distance between the passenger's eyes and the second curved mirror of the imaging device is the eye point distance s1, the distance from the second lens 30 to the first curved mirror 40 is s2, and the distance from the first curved mirror 40 to the second curved mirror 50 is s3.

[0052] Among them, the virtual image distance st = 4000m; the distance from the rear passengers to the front seats is usually about 500mm, which is approximately the eye point distance, that is, s1 = 500mm; then the image distance of the imaging device can be calculated as st-s1 = 4000-500 = 3500mm. The object distance of the imaging device is s2+s3, and the vertical axis magnification = image plane size / image size on the second lens = image distance / object distance. If the resolution at the human eye position is 60ppd and the field of view is 14°×5°, the required resolution of the image can be calculated as the product of the human eye resolution and the field of view, 840pixel×300pixel. The virtual image size is 40 inches = 960mm×320mm; the image size ratio is 3:1, then the image size emitted by the second lens is 60mm×20mm, and the pixel pitch is 0.07mm. According to the visual characteristics of the human eye, the viewing angle of the optical system is designed to be 2°. Due to the space limitations of the seat back, the vertical distance between the components in the imaging device does not exceed 75 mm.

[0053] According to the above parameter restrictions, the first curved mirror 40 can be a convex reflector, the second curved mirror 50 can be a concave reflector, and the surface shapes of the first curved mirror 40 and the second curved mirror 50 can both be XY polynomial free-form surfaces, satisfying the equation:

[0054]

[0055] Among them, z represents the surface equation of the curved mirror, c represents the curvature, k represents the cone coefficient, r represents the radial coordinate, N represents the number of terms in the extended polynomial, and A i represents the coefficient of the i-th expanded polynomial.

[0056] In the embodiment of the present invention, the value N of the curved mirror is 44, and the above equation is expanded to obtain:

[0057] z=c 1 x+c 2 y+c 3 x 2 +c 4 xy+c 5 y 2 +c6 x 3 +c 7 x 2 y+c 8 xy 2 +c 9 y 3 +c 10 x 4 +c 11 x 3 y

[0058] +c 12 x 2 y 2 +c 13 xy 3 +c 14 y 4 +c 15 x 5 +c 16 x 4 y+c 17 x 3 y 2 +c 18 x 2 y 3 +c 19 xy 4

[0059] +c 20 y 5 +c 21 x 6 +c 22 x 5 y+c 23 x 4 y 2 +c 24 x 3 y 3 +c 25 x 2 y 4 +c 26 xy 5 +c 27 y 6

[0060] +c 28 x 7 +c 29 x 6 y+c 30 x 5 y 2 +c 31 x 4 y 3 +c 32 x 3 y 4 +c33 x 2 y 5 +c 34 xy 6 +c 35 y 7 +c 36 x 8 +c 37 x 7 y+c 38 x 6 y 2 +c 39 x 5 y 3 +c 40 x 4 y 4 +c 41 x 3 y 5 +c 42 x 2 y 6

[0061] +c 43 xy 7 +c 44 y 8 ;

[0062] Among them, c 1 is the x-axis trapezoidal change, c 2 is the y-axis trapezoidal change, c 3 and c 5 is the surface magnification, c 4 is the ratio of the four corners of the surface, c 6 to c 44 The value of reflects the adjustment to the surface.

[0063] In some embodiments, for the first curved mirror 40, the parameter c 1 ~c 44 The values ​​are shown in the following table:

[0064]

[0065]

[0066] For the second curved mirror 50, parameter c 1 ~c 44 The values ​​are shown in the following table:

[0067]

[0068]

[0069]

[0070] The distance s2 between the second lens 30 and the first curved mirror 40 along the principal light is 67.824 mm, the distance s3 between the first curved mirror 40 and the second curved mirror 50 along the principal light is -113.026 mm, the inclination angle of the first curved mirror 40 relative to the x-axis is 36.079°, and the inclination angle of the second curved mirror 50 relative to the x-axis is -23.264°.

[0071] When performing optical design, the coefficient of each binomial in the equation affects the aberration. Therefore, during the design process, it is necessary to analyze the aberration according to the simulation results, increase the weight of the coefficient affected by the aberration, and optimize the best solution.

[0072] The above optical system can reduce the size of the vehicle-mounted imaging device to less than 75mm×200mm×200mm, so that the imaging device can be installed in the backrest of the front seat of the vehicle without occupying the space inside the vehicle. The virtual image formed by the vehicle-mounted imaging device is 3m to 4m away from the passenger, and the virtual image size is 20 inches to 40 inches. Passengers have a better experience when watching the image at this distance.

[0073] In the embodiment of the present invention, the image source 10 may be a laser projection device, which includes a laser light source, an illumination system, and a projection lens. The illumination system includes an illumination optical path and an optical modulator. In a specific implementation, the optical modulator may be a digital micromirror (DMD). The laser projection device is a laser projection optical engine based on digital light processing (DLP), which can achieve a resolution of 60PPD.

[0074] The laser light source can emit three-color lasers. Lasers have the characteristics of wide color gamut, high brightness, and narrow spectral bandwidth. The use of laser light sources can improve the color gamut and brightness of displayed images. After the three-color lasers emitted by the laser light source are shaped and homogenized through the illumination light path, the light beams meet the illumination size and incident angle required by the DMD. The surface of the DMD includes many tiny reflectors, each of which can be driven to deflect individually. By controlling the deflection angle of the DMD, the brightness of the light incident on the projection lens is controlled. Finally, the projection lens forms an image and emits the light to display the image.

[0075] Since the vehicle-mounted imaging device provided by the embodiment of the present invention is applied in a vehicle, it will be affected by sunlight and cause the contrast to decrease. In view of this, the embodiment of the present invention further improves the vehicle-mounted imaging device to overcome the above problem.

[0076] Figure 4 The second structural schematic diagram of the vehicle-mounted imaging device provided in an embodiment of the present invention.

[0077] In some embodiments, Figure 4 As shown, in order to improve the contrast of the displayed image, an anti-reflection film 60 is provided on the reflective surface of the second curved mirror 50. The image source 10 adopts a laser projection device, and the output light of the laser projection device is a three-primary-color laser. The anti-reflection film 60 is used to reflect the light of the corresponding wavelength band of the three-primary-color laser emitted by the laser projection device, and absorb the light of other wavelength bands. In this way, even if external light is incident on the second curved mirror 50, most of the light will be absorbed by the anti-reflection film 60, so that most of the light incident on the human eye is the light emitted by the laser projection device, which can effectively suppress sunlight, reduce the influence of ambient light on the displayed image, and improve the contrast of the displayed image.

[0078] Specifically, the anti-reflection film 60 may include a high-refractive index film layer and a low-refractive index film layer stacked together. The product of the refractive index and thickness of the two film layers can satisfy the condition for interfering with the light of the peak wavelengths corresponding to the three-primary color lasers, thereby utilizing the interference between the lasers to enhance the reflection of the three-primary color lasers. Then, the light of other wavelength bands is absorbed by the anti-reflection film 60, thereby achieving the purpose of enhancing the reflection of the three-primary color lasers.

[0079] Since the laser projection device is used as the image source, the laser has higher brightness and color gamut than other light sources, so the displayed image has higher color gamut saturation and larger color gamut, which is conducive to improving image quality. In order to improve the image contrast, a reflection enhancement film can be set on the second curved mirror to enhance the reflection of the light emitted by the laser projection device and inhibit the reflection of other bands of light to the human eye. The laser projection device uses a laser light source. Therefore, in order to inhibit the image from being granular due to laser speckle, in an embodiment of the present invention, a component for eliminating or inhibiting laser speckle can be set in the laser projection device, including but not limited to at least one of a diffuser, a diffuser wheel, a dynamic diffuser, a wave plate, and a dynamic wave plate, so as to reduce the diameter of the laser speckle to the minimum size recognizable by the human eye. The laser projection device has a higher resolution based on the DLP system. Combined with the diffuser (second lens), the resolution of the vehicle-mounted projection device can reach more than 60ppd, thereby avoiding the generation of granularity and improving the viewing experience of passengers. The image refresh rate of the laser projection device is high, and the problem of image flickering will not occur. Therefore, the vehicle-mounted imaging device provided by the embodiment of the present invention can effectively improve the motion sickness of passengers when viewing images, and has a good imaging effect.

[0080] The eyebox range is an important parameter in the field of vehicle-mounted displays. The eyebox refers to the area where the human eye can move. When designing a vehicle-mounted imaging device, it is necessary to ensure that the human eye can see the displayed image clearly within the eyebox area. Since the eyebox heights of passengers of different heights are different, in order to provide passengers of different heights with a better viewing experience when viewing the displayed image, an adjustment unit is also provided in the vehicle-mounted imaging device in the embodiment of the present invention.

[0081] Figure 5 The third structural schematic diagram of the vehicle-mounted imaging device provided in an embodiment of the present invention.

[0082] like Figure 5 As shown, an adjustment part 70 is provided on the side of the first curved mirror 40 away from the second curved mirror 50, and the adjustment part 70 is used to adjust the pitch angle of the first curved mirror 40, thereby adjusting the position where the first curved mirror 40 reflects the light incident on the second curved mirror 50, so as to achieve the purpose of adjusting the imaging height. In this way, the eye box can be adjusted up and down to adapt to passengers of different heights.

[0083] Specifically, the adjusting part 70 can be a rotating shaft, one end of which is connected to the motor and the other end is fixed to the edge of the first curved mirror 40, so as to adjust the pitch angle of the first curved mirror 40 by driving the motor. Of course, the adjusting part 70 can also adopt other forms of modulation structures, as long as the pitch angle of the first curved mirror 40 can be adjusted, which is not limited here.

[0084] The embodiment of the present invention also performs optical simulation on the above-mentioned vehicle-mounted imaging device. According to the design requirements of the visual optical system, the design indicators of the vehicle-mounted imaging optical system provided by the embodiment of the present invention are: MTF>0.3@6lp / mm, TV distortion<2%, and RMS spot within the range of Airy disk. The simulation results can be found in Figure 6 to Figure 10 . Figure 6 A point diagram of a vehicle-mounted imaging device provided by an embodiment of the present invention, Figure 7 The optical transfer function curve diagram of the vehicle-mounted imaging device provided by the embodiment of the present invention is as follows: Figure 8 A TV distortion diagram of a vehicle-mounted imaging device provided by an embodiment of the present invention, Fig. 9 The parallax angle distribution curve of the vehicle-mounted imaging device in the horizontal direction provided by the embodiment of the present invention is as follows: Fig.10 This is a parallax angle distribution curve in the vertical direction of the vehicle-mounted imaging device provided by an embodiment of the present invention.

[0085] After all the light rays emitted by an object point pass through an ideal optical system, they will converge at a point on the image plane, which is the image point of the object point. However, due to the existence of aberrations in actual optical systems, after all the light rays emitted by an object point pass through this optical system, the intersection with the image plane is no longer a point, but a diffuse light spot, which is called a point diagram. The distribution of points in the point diagram can approximately represent the energy distribution of the image point, and the Airy disk can be used as a reference. The Airy disk means that when the diameter of the diffuse spot formed is within 2.44λF, the optical system can be considered to be an ideal optical system, where λ represents the main wavelength and F represents the F number. Figure 6 As shown, the RMS spot of the imaging device provided by the embodiment of the present invention is within the range of the Airy disk and has a better imaging effect.

[0086] like Figure 7 In the optical transfer function curve shown, the horizontal axis represents the spatial frequency, and the vertical axis represents the optical transfer function (Optical Transfer Function, referred to as OTF) modulus. Figure 7 The top curve represents the diffraction limit when the field of view angle is 0. The closer the OTF modulus value at different field of view angles is to the top curve, the better the imaging effect of the imaging system. The optical transfer function curve diagram shows the MTF curves in the sagittal direction and the meridional direction, where the dotted line represents the MTF curve in the sagittal direction, the solid line represents the MTF curve in the meridional direction, and different grayscales represent the MTF curves of light of different wavelengths. Figure 7 As shown, after parameter optimization, the optical transfer function of the vehicle-mounted imaging device provided by the embodiment of the present invention is greater than 0.3@6lp / mm in the full field of view, and has better imaging performance.

[0087] like Figure 8 The TV distortion diagram shown in the figure shows that the horizontal axis represents the x direction and the vertical axis represents the y direction, where “×” represents the real imaging point and “·” represents the ideal imaging point. Figure 8 It can be seen that after the parameters of the vehicle-mounted imaging device provided by the embodiment of the present invention are optimized, the position difference between the real imaging point and the ideal imaging point is small, the TV distortion is less than 1.76%, the distortion amount is small, and the imaging effect is good.

[0088] According to the simulation results, the spot diagram, MTF and TV distortion of the vehicle-mounted imaging device provided by the embodiment of the present invention all meet the design requirements and have good imaging effects.

[0089] like Fig. 9 and Fig.10 As shown, the embodiment of the present invention also analyzes the binocular parallax of the vehicle-mounted imaging device, wherein Fig. 9 and Fig.10 The horizontal axis represents the field of view angle, and the vertical axis represents the parallax angle. Fig. 9and Fig.10 It can be seen that the parallax angle in the horizontal direction is <2mrad, and the parallax angle in the vertical direction is <0.1mrad. In the dynamic distortion analysis, the distortion difference of each eye point in the middle eye box is <3.3%.

[0090] According to the first inventive concept, the vehicle-mounted imaging device provided by the embodiment of the present invention includes: an image source, a first lens, a first lens, a first curved mirror, and a second curved mirror. The image light emitted by the image source is first incident on the first lens and then reflected by the first lens to the second lens. The first lens reflects the incident light to the first curved mirror, which is then reflected to the second curved mirror by the first curved mirror, and then reflected to the passenger's position by the second curved mirror. The exit surface of the second lens serves as the object surface, and the first curved mirror and the second curved mirror are used to image the image light emitted by the second lens, thereby forming a large-sized virtual screen at a set position in front of the passenger. No longer restricted by the space inside the car, passengers can watch large-sized images at a comfortable viewing distance. At this time, the adjustment force of the ciliary muscles of the human eye remains unchanged, which can reduce visual fatigue and alleviate motion sickness caused by watching the screen at a close distance.

[0091] According to the second invention concept, the image source adopts a laser projection device, which has the characteristics of wide color gamut, high brightness and narrow spectral bandwidth. The use of a laser light source can improve the color gamut and brightness of the displayed image. At the same time, the laser projection device can realize a display image with a resolution of 60ppd.

[0092] According to the third inventive concept, the second lens uses a reflective diffuser. The outgoing surface of the diffuser is used as the object surface, and the surface receiving light can be provided with a microstructure, and the surface away from the microstructure is silver-plated for reflecting light. The microstructure can make the diffusion angle of the outgoing light match the field of view angle of the optical system and increase the system light efficiency.

[0093] According to the fourth invention concept, the first curved mirror and the second curved mirror are designed to form a virtual image of incident light at a set position in front of the passenger, thereby forming a large-sized virtual screen in front of the passenger. The distance between the virtual screen formed by the on-board imaging device and the passenger is 3m to 4m, and the size of the virtual screen viewed by the passenger is 20 inches to 40 inches, which is equivalent to the passenger being able to view a 20-inch to 40-inch image at a position 3m to 4m in front of the passenger.

[0094] According to the fifth invention concept, the first curved mirror is a convex reflector, the second curved mirror is a concave reflector, and the surface shapes of the first curved mirror and the second curved mirror can both be XY polynomial free-form surfaces.

[0095] According to the sixth invention concept, a reflection enhancement film is provided on the reflection surface of the second curved mirror. The image source adopts a laser projection device, the output light of the laser projection device is a three-primary-color laser, and the reflection enhancement film is used to reflect the light of the corresponding wavelength band of the three-primary-color laser emitted by the laser projection device, and absorb the light of other wavelength bands. In this way, even if external light is incident on the second curved mirror, most of the light will be absorbed by the reflection enhancement film, so that most of the light incident on the human eye is the light emitted by the laser projection device, which can effectively suppress sunlight, reduce the influence of ambient light on the displayed image, and improve the contrast of the displayed image.

[0096] According to the seventh invention, an adjustment part is provided on the side of the first curved mirror away from the second curved mirror, and the adjustment part is used to adjust the pitch angle of the first curved mirror, thereby adjusting the position where the first curved mirror reflects the light incident on the second curved mirror, so as to achieve the purpose of adjusting the imaging height. In this way, the eye box can be adjusted up and down to adapt to passengers of different heights.

[0097] According to the eighth inventive concept, the simulation data of the vehicle-mounted imaging device provided by the embodiment of the present invention satisfies: MTF>0.3@6lp / mm, TV distortion<2%, RMS spot is within the Airy disk range, the parallax angle in the horizontal direction is<2mrad, the parallax angle in the vertical direction is<0.1mrad, and in the dynamic distortion analysis, the distortion difference of each eye point in the middle eye box is<3.3%.

[0098] According to the ninth inventive concept, the size of the vehicle-mounted imaging device is less than or equal to 75 mm×200 mm×200 mm, and can be installed in the backrest of the front seat of the vehicle.

[0099] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0100] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A vehicle-mounted imaging device, It is characterized in that include: An image source, used for emitting image light; A first lens is located at the light-emitting side of the image source; the first lens receives and reflects the emitted light from the image source; A second lens is located on the path of the reflected light of the first lens; the second lens is used to change the divergence angle of the incident light and reflect it; Two curved mirrors, namely a first curved mirror and a second curved mirror, the first curved mirror is located on the path of the reflected light of the second lens, and the second curved mirror is located on the path of the reflected light of the first curved mirror; the first curved mirror receives the light reflected by the second lens and reflects it toward the second curved mirror, and the second curved mirror receives the light reflected by the first curved mirror and reflects it toward the position of the passenger, and the first curved mirror and the second curved mirror are used to image the incident light beam at a set position in front of the passenger.

2. The vehicle-mounted imaging device according to claim 1, It is characterized in that The first lens is a plane reflecting mirror.

3. The vehicle-mounted imaging device according to claim 2, It is characterized in that The first curved mirror is a convex reflecting mirror, and the second curved mirror is a concave reflecting mirror.

4. The vehicle-mounted imaging device according to claim 3, It is characterized in that The surface shapes of the first curved mirror and the second curved mirror are both free-form surfaces.

5. The vehicle-mounted imaging device according to claim 4, It is characterized in that The surface shapes of the first curved mirror and the second curved mirror satisfy: Wherein, z represents the surface equation of the first curved mirror or the second curved mirror, c represents the curvature, k represents the cone coefficient, r represents the radial coordinate, N represents the number of terms of the extended polynomial, and A i represents the coefficient of the i-th expanded polynomial.

6. The vehicle-mounted imaging device according to any one of claims 1 to 5, It is characterized in that The image source is a laser projection device, and the laser projection device emits three-color lasers.

7. The vehicle-mounted imaging device according to claim 6, It is characterized in that A reflection enhancement film is arranged on the reflection surface of the second curved mirror, and the reflection enhancement film is used to reflect the light of the corresponding wavelength band of the three-color laser emitted by the laser projection device and absorb the light of other wavelength bands.

8. The vehicle-mounted imaging device according to any one of claims 1 to 5, It is characterized in that An adjustment portion is provided on a side of the first curved mirror facing away from the second curved mirror, and the adjustment portion is used to adjust the pitch angle of the first curved mirror to adjust the imaging height.

9. The vehicle-mounted imaging device according to any one of claims 1 to 5, It is characterized in that The distance between the imaging device and the passenger is 3m to 4m; The image size viewed by passengers is 20 inches to 50 inches.

10. The vehicle-mounted imaging device according to any one of claims 1 to 5, It is characterized in that The size of the vehicle-mounted imaging device is less than or equal to 75 mm×200 mm×200 mm, and the vehicle-mounted imaging device is installed in the backrest of the front seat of the vehicle.

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