CN112558301A

CN112558301A - Imaging optical system

Info

Publication number: CN112558301A
Application number: CN202011033855.6A
Authority: CN
Inventors: 熊全宾; 郑舜文
Original assignee: Sitronix Technology Corp
Current assignee: Sitronix Technology Corp
Priority date: 2019-09-26
Filing date: 2020-09-27
Publication date: 2021-03-26

Abstract

The invention relates to an imaging optical system, which comprises a windshield, wherein the windshield comprises a first glass layer and a second glass layer, a fixed distance is formed between the first glass layer and the second glass layer, the transverse axial curvature of the first glass layer and the second glass layer is more than 3.5 meters, the longitudinal axial curvature of the first glass layer and the second glass layer is more than the transverse axial curvature, and an optical imaging device can reduce double image when being matched with the windshield for imaging.

Description

Imaging optical system

Technical Field

The present invention relates to an optical system, and more particularly to an imaging optical system with reduced ghost phenomenon.

Background

With the progress of optical and electronic technologies, optical imaging devices are being developed for various applications in daily life, such as projectors, liquid crystal displays, etc., and nowadays, manufacturers have developed Head Up Displays (HUDs), which are commonly referred to as HUDs, for drivers on vehicles, and are currently widely used as driving aids for drivers, so that the drivers can view important driving information within the driving sight range without looking down at an instrument panel in front of the drivers, thereby reducing the frequency of looking at the instrument in a low Head manner, avoiding attention interruption or losing the grasp of state awareness, and improving the driving safety.

However, when the HUD projects an image onto a normal windshield, as shown in FIG. 1, under the condition that a first glass plane P1 and a second glass plane P2 of the normal windshield G are equally spaced, corresponding to two parallel planes, the image source IMS emits a main image light L1 and a double image light L2 onto the first glass plane P1 and the second glass plane P2 of the windshield G respectively, wherein the main shadow light L1 is reflected by the first glass surface P1 to form a main shadow reflected light R1, so as to form a main shadow spot R1C on the first glass surface P1 and reflect to an EYE EYE of a driver, the ghost light ray L2 is incident to the windshield G and refracted, that is, the reflected light passes through the first glass surface P1 and is reflected by the second glass surface P2, and then exits the first glass surface P1 of the windshield G and is refracted to form a double image reflected light R2, to form a ghost light spot R2C on the first glass surface P1 for reflection to the EYE.

Referring to fig. 1 again, the EYE receives the main reflected light R1 and the ghost reflected light R2 of the image source IMS, that is, the first virtual image I1 and the second virtual image I2 are formed in front of the windshield G relative to the main shadow light point R1C and the ghost light point R2C, the first virtual image I1 and the second virtual image I2 are not overlapped, and the EYE sees the first virtual image I1 and the second virtual image I2, thereby forming a ghost, which is also referred to as a ghost phenomenon. As shown in fig. 2, the distance between the image source IMS and the windshield G is inversely proportional to the distance between the main image light point R1C and the ghost light point R2C, so that as the distance between the image source IMS and the windshield G increases from 1000 millimeters (mm) to 8000 millimeters (mm), the distance between the main image light point R1C and the ghost light point R2C decreases from 2 millimeters (mm) to approximately 0.25 millimeters (mm), but does not overlap, and therefore, referring to fig. 1 and 2 again, the EYE of the user sees the first virtual image I1 and the second virtual image I2, so that a ghost phenomenon occurs, and it is difficult for the user of the HUD to clearly recognize the content of the HUD.

In addition, in order to solve the above problem, the HUD needs to be matched with a dedicated HUD windshield, so that the cost of the HUD product is increased, and the cost of the vehicle is increased due to the increased cost.

In view of the above problems, the present invention provides an imaging optical system that can reduce ghost images, further reduce the use dependence of a HUD-dedicated windshield, and reduce the cost of purchasing cars and the cost of future maintenance.

Disclosure of Invention

An objective of the present invention is to provide an imaging optical system, which includes a windshield, a curvature of the windshield in a transverse axis direction is greater than 3.5 m, and a curvature of the windshield in a longitudinal axis direction is greater than the curvature in the transverse axis direction, so that when an optical imaging device is used to image in cooperation with the windshield, ghost images can be reduced.

In view of the above, the present invention provides an imaging optical system, which includes a windshield, the windshield including a first glass layer and a second glass layer, the first glass layer and the second glass layer having a fixed distance therebetween, a transverse-axis direction curvature of the first glass layer and the second glass layer being greater than 3.5 meters, and a longitudinal-axis direction curvature of the first glass layer and the second glass layer being greater than the transverse-axis direction curvature.

Drawings

FIG. 1: which is an imaging schematic diagram of an imaging optical system in the prior art;

FIG. 2: it is a curve diagram of the separation distance between the image source and the windshield to the separation distance between the main image light spot and the ghost light spot in the prior art;

FIG. 3: which is a schematic view of an imaging optical system according to an embodiment of the present invention

FIG. 4: the imaging schematic diagram of the windshield with the non-parallel surface is shown in the invention;

FIG. 5: it is a curve chart of the spacing distance between the image source and the windshield to the spacing distance between the main image light spot and the ghost light spot;

FIG. 6: which is an imaging schematic diagram of an imaging optical system according to an embodiment of the present invention;

FIG. 7: which is an imaging schematic diagram of an imaging optical system according to an embodiment of the present invention;

FIG. 8: which is a plot of the separation distance between the image source and the windshield versus the separation distance between the main image spot and the ghost spot.

[ brief description of the drawings ]

10 imaging optical system

12 windscreen

12A reflective area

122 first glass layer

124 second glass layer

14 optical imaging device

142 display source

142A first optical path

144 mirror

144A second optical path

146 spherical mirror

Center of a CC concentric circle

First curve of CV1

Second curve of CV2

Third curve of CV3

D1 distance apart

EYE of EYE

G windshield

G1 windshield

I1 first virtual image

I2 second virtual image

IMG image

IMS image source

L1 main shadow ray

L2 ghost ray

M1 imaging distance

M2 throw distance

N1 first normal

Second normal of N2

OP optical component

P1 first plane

P12 first plane

P2 second plane

P22 second plane

R1 reflection light

R1C dominant spot

R12 reflection light

R12C dominant spot

R2 ghost reflected light

R2C ghost light point

R22 ghost reflected light

R22C ghost light point

RR1 first reflection point

RR2 second reflection point

RR2C ghost spots

RR2I incident Point

T1 first tangent line

Second tangent line of T2

V1 first virtual image

Virtual V1C image region

V2 second virtual image

V3 third virtual image

VL1 main shadow ray

VL2 ghost ray

VR1 reflection of the main shadow

VR2 ghost reflected light

X X axial curvature

Y Y axial curvature

Detailed Description

In order to provide a further understanding and appreciation for the structural features and advantages achieved by the present invention, the following detailed description of the presently preferred embodiments is provided:

hereinafter, various embodiments of the present invention will be described in detail by way of the drawings. The inventive concept may, however, be embodied in many different forms and should not be construed as being limited to the exemplary embodiments set forth herein.

A schematic diagram of an imaging optical system of the present invention is shown in fig. 3. As shown in the drawings, the imaging optical system 10 of the present invention includes a windshield 12, the windshield 12 includes a first glass layer 122 and a second glass layer 124, the windshield 12 of the present embodiment is a windshield for providing a vehicle, the first glass layer 122 and the second glass layer 124 have a fixed distance therebetween, which is equivalent to the distance between the first glass layer 122 and the second glass layer 122 is fixed, which means that the first glass layer 122 and the second glass layer 124 are two glass layers parallel to each other, and the first glass layer 122 and the second glass layer 124 have curvatures, so that the center of circle of the first glass layer 122 and the center of circle of the second glass layer 124 are the same center of circle, and the surface of the first glass layer 122 and the surface of the second glass layer 124 are parallel free surfaces.

A first virtual image V1 is used as an image source, and a distance is provided between the virtual image region V1C where the first virtual image V1 is located and the center CC of the first glass layer 122 and the center CC of the second glass layer 124 of the windshield 12, that is, the virtual image region V1C is located at the center of a non-concentric circle (as shown in fig. 7). A first reflection point RR1 is formed on the first glass layer 122 and corresponds to the visual region V.

Referring back to fig. 3, the present embodiment further includes an optical imaging device 14, which includes a display source 142 and an optical element OP, in particular, in the present embodiment, the optical assembly OP further comprises a reflecting mirror 144 and a spherical mirror 146, the optical assembly OP is located on a first optical path 142A of the display source 142, in particular, mirror 144 is positioned in first optical path 142A of display source 142, the spherical mirror 146 is located on a second optical path 144A of the reflective mirror 144, the display source 142 outputs an image IMG to the reflective mirror 144 for reflection to the spherical mirror 146, so that the spherical mirror 146 projects the image IMG to the reflection area 12A of the windshield 12, to be reflected to the visual region V, and the first optical path 142A and the second optical path 144A may be smaller than the focal length of the spherical mirror 146, thereby forming a first virtual image V1, it shows that the optical assembly OP of the optical imaging device 14 images the first virtual image V1 corresponding to the reflective area 12A. The optical imaging device 14 images a first virtual image V1, and the first virtual image V1 is located below the windshield 12 as an image source, so that the first virtual image V1 forms reflected light rays to the visual area V through the first reflection point RR 1.

Referring back to fig. 3, the surface of the first glass layer 122 and the surface of the second glass layer 124 both have curvatures and are free surfaces, and the curvature X in the transverse (X-axis) direction is greater than 3.5 meters, and the curvature Y in the longitudinal (Y-axis) direction is greater than the curvature in the transverse direction, and in an embodiment of the invention, the curvature Y in the Y-axis direction may be greater than 6 meters. The first virtual image V1 is located at the center of a non-concentric circle between the first glass layer 122 and the second glass layer 124 (as shown in fig. 7), so that when the first virtual image V1 is projected onto the windshield 12, the first reflection point of the first glass layer 122 and the second reflection point of the second glass layer 124, which reflect the first virtual image V1, are located on non-parallel surfaces. Assuming that an angle is formed between a first plane P12 and a second plane P22 of a non-parallel glass G1, such as 0.05 degree, as shown in fig. 4, the glass G1 can be used as a windshield, when the image source IMS is located on one side of the non-parallel glass G1, the main image light L1 of the image source IMS forms a main image light point R12C on the first plane P12 and reflects to form a main image reflected light R12 to be projected to the EYE, the ghost light L2 of the image source IMS refracts through the first plane P12, reflects through the second plane P22 and refracts through the first plane P12 to form ghost reflected light R22, i.e., a ghost light point R22C is formed on the first plane P12, and the ghost light R22 is also projected to the EYE. The EYE receives the main reflected light R12 and the ghost reflected light R22 of the image source IMS, i.e., the main ghost point R12C and the ghost point R22C, and forms two virtual images I12 and I22 in front of the windshield G1.

As shown in fig. 5, as the distance between the image source IMS and the glass G1 increases, the distance between the main image point R12C and the ghost point R22C decreases, and the distance between the main image point R12C and the ghost point R22C of this embodiment is zeroed out in that the distance between the image source IMS and the glass G1 is slightly 1600 mm, and the distance between the image source IMS and the glass G1 exceeds 1600 mm, so that the main image point R12C and the ghost point R22C are staggered, for example, the ghost point R22C is located above the main image point R12C, and the ghost point R22C is located below the main image point R12C and the distance between the ghost point R22C and the main image point R12C increases with the distance between the image source IMS and the glass G1 exceeding 1600 mm. Adjusting the angle between the first plane P12 and the second plane P22 adjusts the relationship between the distance between the main image point R12C and the ghost point R22C relative to the distance between the image source IMS and the glass G1, in other words, further adjusts the distance between the image source IMS and the glass G1 when the distance between the main image point R12C and the ghost point R22C is zero.

Referring to fig. 3, in the imaging optical system 10 of the present invention, the first reflective region 12A has a separation distance D1 with respect to the first virtual image V1, the separation distance D1 is equivalent to an imaging distance M1 from the spherical mirror 146 to the first virtual image V1 and a projection distance M2 from the spherical mirror 146 to the reflective region 12A, which is equivalent to an imaging distance from the optical element OP to the first virtual image V1 and a projection distance from the optical element OP to the reflective region 12A for projecting the image IMG, and the separation distance D1 is smaller than 1/2X-axis curvature X, and the X-axis curvature is larger than 3.5 meters, and the Y-axis curvature Y is larger than the X-axis curvature X, and further, the Y-axis curvature Y may be larger than 6 meters. Thus, ghost phenomena can be reduced. In addition, the optical path of the image IMG passing through the optical assembly OP corresponds to the imaging distance M1 from the first virtual image V to the optical imaging device 14, in other words, the distance from the image source 142 to the reflective mirror 144 (the distance of the first optical path 142A) and the reflection distance from the reflective mirror 144 to the spherical mirror 146 (the distance of the second optical path 144A) correspond to the imaging distance M1 from the first virtual image V1 to the optical imaging device 14.

Please refer to fig. 6 and fig. 7, which are schematic imaging diagrams of an imaging optical system according to an embodiment of the present invention. As shown in fig. 6, the display source 142 projects the image IMG to the windshield 12 by reflection of the optical element OP, so as to form a first virtual image V1, in other words, the corresponding spherical mirror 146 forms a first virtual image V1, the first virtual image V1 is located at the non-concentric circle center of the reflection region 12A, the first virtual image V1 is equivalent to the image source projected to the windshield 12, the imaging distance from the optical element OP to the first virtual image V1 plus the reflection distance from the optical element OP to the reflection region 12A for projecting the image IMG is smaller than 1/2X-axis curvature X, so that the first virtual image V1 falls within the focal length of the virtual image imaged by the windshield 12, so as to image a second virtual image V2 and a third virtual image V3, the second virtual image V2 corresponds to the main light spot, and the third virtual image V3 corresponds to the virtual light spot.

As mentioned above, the imaging distance from the optical element OP to the first virtual image V1 and the projection distance from the optical element OP to the reflection region 12A for projecting the image IMG are smaller than the curvature X in the X-axis direction of 1/2, and since the curvature X in the X-axis direction is larger than 3.5 meters and the curvature Y in the Y-axis direction is larger than the curvature X in the X-axis direction, the second virtual image V2 and the third virtual image V3 are equivalent to imaging in a distance corresponding to the visual region V (the region seen by the eyes). Each point on the virtual image region V1C corresponds to each point of the reflection region 12A.

As shown in fig. 7, the first glass layer 122 and the second glass layer 124 have a first reflection point RR1 and a second reflection point RR2 relative to the first virtual image V1, the first glass layer 122 and the second glass layer 124 have the same center and correspond to concentric glass, the first normal N1 corresponds to the first reflection point RR1 to a concentric center position CC, the second normal N2 corresponds to the second reflection point RR2 to the concentric center position CC, the first virtual image V1 is not located at the concentric center position CC, which indicates that the first virtual image V1 is located at a non-concentric center position, and also indicates that the first reflection point RR1 is located at the center position (the first position) of the first glass layer 122, the second reflection point RR2 is located at the center position (the second position) of the second glass layer 124, the first virtual image V1 has a distance from the center position CC of the concentric center of the first position and the center position CC of the second glass layer 124, thus, the first tangent T1 and the second tangent T2 corresponding to the first normal N1 and the second normal N2 have different tangent angles, which means that the first tangent T1 and the second tangent T2 are not parallel to each other, i.e., the first tangent T1 and the second tangent T2 are not on the same normal line, so that the tangent positions of the first tangent T1 and the second tangent T2 are different, which corresponds to the main light ray VL1 and the ghost light ray VL2 of the embodiment of fig. 4 being reflected by the first plane P12 and the second plane P22, respectively, which are not parallel to each other. The first reflection point RR1 is located on the first tangent T1, and the second reflection point RR2 is located on the second tangent T2. Thus, based on fig. 4 and 5 and the corresponding description, the windshield 12 of the embodiment of fig. 6 and the optical imaging device 14 can make the main image light point and the auxiliary image light point approach and overlap to reduce the ghost phenomenon. In addition, the windshield 12 further includes an interlayer 126, i.e., the interlayer 126 is disposed between the first glass layer 122 and the second glass layer 124.

Referring to fig. 7, the first virtual image V1 projects a main shadow light VL1 and a ghost light VL2 to the first glass layer 122, and the main shadow light VL1 is reflected at a first reflection point RR1 of the first glass layer 122 to form a main shadow reflected light VR1 to be projected to the EYE, where the first reflection point RR1 is also a main shadow light point; the ghost light ray VL2 passes through the first glass layer 122 and is refracted and incident on the second glass layer 124 through the interlayer 126, so that an incident point RR2I is formed, the ghost light ray VL2 is refracted at the incident point RR2I to the second glass layer 124 to be reflected at the second reflection point RR2 on the surface of the second glass layer 124, so that ghost reflected light VR2 is formed, and is refracted through the first glass layer 122, so that a ghost light point RR2C is formed, and the ghost reflected light VR2 is projected to the EYE after exiting the first glass layer 122. Based on the first and second reflection points RR1 and RR2 being located on the first and second tangents T1 and T2 that are not parallel to each other, the first and second reflection points RR1 and RR2 are equivalent to two non-parallel surfaces located on the glass G1, so that the second and third virtual images V2 and V3 corresponding to the main-image reflected light VR1 and the ghost reflected light VR2 can be overlapped to reduce or eliminate the ghost phenomenon.

Referring to fig. 8, a first curve CV1 is a curve of a distance between a main image light point and a ghost light point relative to a distance between an image source and a windshield in an optical system including a windshield having a non-parallel surface; a second curve CV2 is a curve of the distance between the main image spot and the ghost spot relative to the distance between the image source and the windshield in an optical system including a windshield of the present invention; the third curve CV3 is a plot of the distance between the main and ghost spots versus the distance between the image source and the windshield in an optical system including a windshield having generally parallel glass. It can be seen from the third curve CV3 that how the distance between the image source and the windshield of a windshield including generally parallel glass increases still cannot make the main image light spot and the ghost light spot coincide with each other.

On the other hand, the curvature of the windshield of the imaging optical system of the present invention in the transverse axis direction is greater than 3.5 m, and the curvature in the longitudinal axis direction is greater than the curvature in the transverse axis direction, so that the main image light point and the ghost light point can be overlapped according to the second curve CV2, for example, in the case that the distance between the main image light point and the ghost light point is set to 0, the distance between the image source and the windshield is about 4000 mm (mm), and in comparison with the windshield having a non-parallel surface which is expensive in terms of cost, the first curve CV1 is relative to the second curve CV2, the distance between the image source and the windshield is shorter, the distance between the image source and the ghost light point can be overlapped, as shown in the figure, in the case that the distance between the main image light point and the ghost light point is set to 0, but the manufacturing cost and the price of the windshield having the non-parallel surface are higher, and it is not easy to apply all the vehicle money widely, the invention can provide an optical system which can enable the HUD to be widely applied to all vehicle models, so that the invention can break the thoughts of the special HUD glass, thereby reducing the use dependence of the special HUD windshield.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not intended to limit the scope of the present invention, which is defined by the appended claims.

Claims

1. An imaging optical system, comprising:

the windshield comprises a first glass layer and a second glass layer, a fixed distance is reserved between the first glass layer and the second glass layer, the curvature of the first glass layer and the second glass layer in the transverse axis direction is larger than 3.5 meters, and the curvature of the first glass layer and the second glass layer in the longitudinal axis direction is larger than the curvature of the first glass layer and the second glass layer in the transverse axis direction.

2. The imaging optical system of claim 1, wherein a first virtual image is located below the windshield, the first virtual image being reflected by the windshield to form a second virtual image.

3. The imaging optical system of claim 2, wherein the first glass layer and the second glass layer have a first reflection point and a second reflection point corresponding to the first virtual image, the first reflection point is located at a first tangent line, the second reflection point is located at a second tangent line, and the first tangent line and the second tangent line are not parallel to each other.

4. The imaging optical system according to claim 3, wherein the first reflection point is located at a first position of the first glass layer, the second reflection point is located at a second position of the second glass layer, and the first virtual image has a distance from a center of the first position and a center of the second position, respectively.

5. The imaging optical system of claim 2, further comprising:

an optical imaging device is used for imaging the first virtual image corresponding to a reflection area of the windshield, and the distance between the first virtual image and the reflection area is smaller than half of the curvature of the transverse axis direction.

6. The imaging optical system of claim 5, wherein the separation distance is an imaging distance from the first virtual image to the optical imaging device plus a projection distance from the optical imaging device to the reflective region.

7. The imaging optical system of claim 5, wherein the optical imaging device comprises a display source and an optical element, the display source outputting an image to the optical element to image the first virtual image.

8. The imaging optical system of claim 7, wherein the optical assembly comprises a mirror and a spherical mirror, the mirror reflecting the image to the spherical mirror such that the spherical mirror images the first virtual image.

9. The imaging optical system of claim 8, wherein the separation distance is an imaging distance from the first virtual image to the spherical mirror plus a projection distance from the spherical mirror to the reflective region.

10. The imaging optical system of claim 5, wherein an optical path of the optical imaging device corresponds to an imaging distance from the first virtual image to the optical imaging device.

11. The imaging optical system according to claim 5, wherein a virtual image region of the first virtual image corresponds to the reflection region.

12. The imaging optical system according to claim 1, wherein the longitudinal axis direction curvature is greater than 6 meters.

13. The imaging optical system according to claim 1, wherein the windshield includes an interlayer disposed between the first glass layer and the second glass layer.