Image generation device and head-up display

Abstract

The embodiment of the invention provides an image generation device and a head-up display. The image generation device comprises a projection lens and a projection surface located on the light emitting side of the projection lens. The projection lens comprises a fixed lens group and a movable lens group, the movable lens group can move along the optical axis of the projection lens, and the position of the projection surface is adjusted according to the projection distance range, so that the head-up display projects virtual images with different virtual image distances.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of display technology, and more specifically, to an image generating device and a head-up display. Background Art

[0002] With the continuous progress of the automotive industry, in order to ensure that the safety and comfort of driving are significantly improved, the head-up display system (HUD) has been introduced into the design of automotive intelligent cockpits. However, the HUD systems currently on the market generally use a fixed virtual image distance setting. This limitation limits the ability of HUD to provide users with a more optimized driving experience in different driving environments. In addition, the clarity of the image displayed on the projection surface of the traditional head-up display is not high, which affects the projection quality.

[0003] In view of this, it is necessary to provide a new technical solution to solve the above technical problems. Summary of the invention

[0004] The purpose of this application is to provide a new technology solution for an image generating device and a head-up display.

[0005] The present application provides an image generating device. The image generating device is applied to a head-up display, a projection lens and a projection surface located on the light-emitting side of the projection lens;

[0006] The projection lens includes a fixed lens group and a movable lens group. The movable lens group can move along the optical axis of the projection lens to adjust the position of the projection surface according to the projection distance range, so that the head-up display projects virtual images with different virtual image distances.

[0007] Optionally, the movable lens group is located at the light-exiting side of the fixed lens group, or the movable lens group is located at the light-incoming side of the fixed lens group.

[0008] Optionally, the lens of the movable lens group farthest from the fixed lens group is an aspherical lens.

[0009] Optionally, the movable lens group is located at the light-emitting side of the fixed lens group, the overall optical power of the movable lens group is negative, and the overall optical power of the fixed lens group is positive.

[0010] Optionally, the movable lens group is located at the light incident side of the fixed lens group, the overall optical power of the movable lens group is positive, and the overall optical power of the fixed lens group is negative.

[0011] Optionally, the projection distance range between the projection surface and the projection lens satisfies: 120 mm ≤ T ≤ 140 mm.

[0012] Optionally, the movable lens group is located at the light-emitting side of the fixed lens group, and the distance T1 between the movable lens group and two adjacent lenses in the fixed lens group satisfies: 3.15 mm <T1<3.35mm。

[0013] Optionally, the projection lens further comprises an equivalent prism, the movable lens group is located at the light-emitting side of the equivalent prism, and the distance T2 between the lens in the movable lens group farthest from the fixed lens group and the equivalent prism satisfies: 5.5 mm <T2<5.9mm。

[0014] Optionally, the movable lens group is located at the light incident side of the fixed lens group, and the distance T3 between the movable lens group and two adjacent lenses in the fixed lens group satisfies: 0.01 mm <T3<0.2mm。

[0015] Optionally, the lens aperture of the projection lens closest to the projection surface is D1, and the effective focal length of the projection lens is EFL, wherein D1 / EFL<0.95.

[0016] Optionally, the total length of the projection lens is TTL, and the effective focal length of the projection lens is EFL, wherein TTL / EFL<4.5.

[0017] Optionally, the projection lens further comprises an adjusting mechanism, and the ineffective area of ​​the lens in the movable lens group is arranged on the adjusting mechanism, and the adjusting mechanism drives the movable lens group to move along the optical axis of the projection lens.

[0018] Optionally, the adjustment mechanism comprises a main body, a concave groove is formed on a side of the main body facing the movable lens group, and a sliding groove is formed in the concave groove;

[0019] The adjustment mechanism also includes a sliding portion, the ineffective area of ​​the lens in the movable lens group is connected to the sliding portion, the sliding portion is at least partially located in the recessed groove, and the sliding portion is embedded in the sliding groove to drive the movable lens group to move along the optical axis of the projection lens.

[0020] Optionally, the projection lens includes: a fifth lens, a fourth lens, a third lens, a second lens and a first lens arranged in sequence along the optical axis, the first lens is arranged adjacent to the projection surface, and the optical focal lengths of the fifth lens, the fourth lens, the third lens, the second lens and the first lens are: positive, positive, negative, positive, negative, respectively; the first lens is configured to be able to move along the optical axis, or the fifth lens is configured to be able to move along the optical axis.

[0021] Optionally, the projection distance range between the first lens and the projection surface satisfies 120 mm≤T≤140 mm.

[0022] Optionally, the first lens is an aspherical lens, and the fifth lens is an aspherical lens.

[0023] Optionally, when the first lens is configured to be movable along the optical axis, the distance T1 between the first lens and the second lens satisfies: 3.15 mm <T1<3.35mm。

[0024] Optionally, when the fifth lens is configured to be movable along the optical axis, the distance T3 between the fifth lens and the fourth lens satisfies: 0.01 mm <T3<0.2mm。

[0025] Optionally, the projection lens further includes an equivalent prism, the fifth lens is configured to be movable along the optical axis, and a distance T2 between the fifth lens and the equivalent prism satisfies: 5.5 mm <T2<5.9mm。

[0026] Optionally, the projection lens satisfies: -1.1 <EFL / f1<-0.95;0.95<EFL / f2<1.05;-1.25<EFL / f3<-1.15;0.93<EFL / f4<0.98;0.65<EFL / f5<0.75;

[0027] Among them, EFL is the effective focal length of the projection lens, f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, and f5 is the focal length of the fifth lens.

[0028] Optionally, the third lens and the fourth lens are cemented to form a cemented lens group.

[0029] In a second aspect, an embodiment of the present application further provides a head-up display, wherein the head-up display comprises the image generating device as described in the first aspect.

[0030] According to an embodiment of the present application, the projection lens in the image generating device includes a movable lens group, which can move along the optical axis of the projection lens, and the projection surface can adjust its setting position within the projection distance range. On the one hand, it can ensure that the projection surface displays a higher-definition image. On the other hand, the image generating device is applied to a head-up display, and the head-up display can project virtual images with different virtual image distances.

[0031] Other features and advantages of the present specification will become apparent from the following detailed description of exemplary embodiments of the present specification with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the specification and, together with the description, serve to explain the principles of the specification.

[0033] Figure 1 The figure shows the optical path of the projection lens provided in the embodiment of the present application. Figure 1 .

[0034] Figure 2 The structure of the projection lens provided in the embodiment of the present application is shown as follows Figure 1 .

[0035] Figure 3a to Figure 3e Shown Figure 2 MTF graphs for the projection lenses shown at projection distances of 120mm, 125mm, 130mm, 135mm, and 140mm.

[0036] Figure 4a to Figure 4e Shown Figure 2 Field curvature / distortion plots for the projection lenses shown at projection distances of 120mm, 125mm, 130mm, 135mm, and 140mm.

[0037] Figure 5 Shown Figure 2 The figure shows a curve diagram of the change in position of the first lens relative to the second lens when the projection distance of the projection lens changes by 2 mm at a time from 120 mm to 140 mm.

[0038] Figure 6 The figure shows the optical path of the projection lens provided in the embodiment of the present application. Figure 2 .

[0039] Figure 7 The structure of the projection lens provided in the embodiment of the present application is shown as follows Figure 2 .

[0040] Figure 8a to Figure 8e Shown Figure 7 MTF graphs for the projection lenses shown at projection distances of 120mm, 125mm, 130mm, 135mm, and 140mm.

[0041] Figure 9a to Figure 9e Shown Figure 7 Field curvature / distortion plots for the projection lenses shown at projection distances of 120mm, 125mm, 130mm, 135mm, and 140mm.

[0042] Fig.10 Shown Figure 7 The figure is a curve diagram showing the change of the position of the fifth lens relative to the equivalent prism when the projection distance of the projection lens changes by 2 mm at a time from 120 mm to 140 mm.

[0043] Description of reference numerals:

[0044] 101. movable lens group; 102. fixed lens group;

[0045] 20, first lens; 21, second lens; 22, third lens; 23, fourth lens; 24, fifth lens;

[0046] 31. Equivalent prism; 32. Protective glass; 33. DMD; 34. Aperture;

[0047] 4. Adjustment mechanism; 41. Main body; 42. Sliding part;

[0048] 5. Projection surface; DETAILED DESCRIPTION

[0049] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application.

[0050] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present application, its application, or uses.

[0051] Techniques and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the techniques and equipment should be considered part of the specification.

[0052] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0053] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0054] The embodiment of the present application provides an image generating device, which is applied to a head-up display. The image generating device of the head-up display is used to generate image information and project it onto a projection surface 5 through a projection lens of the image generating device. In this process, the movable lens group 101 inside the projection lens can be flexibly moved along the optical axis. As the movable lens group 101 moves, the position of the projection surface 5 in the image generating device will also be adjusted accordingly. By adjusting the setting positions of the movable lens group 101 and the projection surface 5, effective projection can be achieved within a projection distance range. Since the position of the projection surface 5 changes, the head-up display flexibly adjusts the distance of the virtual picture (virtual image distance) according to the actual projection distance between the projection surface 5 and the movable lens group 101.

[0055] In the embodiments of this application, refer to Figure 1 and Figure 2 as well as Figure 6 and Figure 7 The image generating device comprises: a projection lens and a projection surface 5 located at the light exiting side of the projection lens. The projection lens comprises a fixed lens group 102 and a movable lens group 101; the movable lens group 101 can move along the optical axis of the projection lens, and adjust the position of the projection surface 5 according to the projection distance range, so that the head-up display projects virtual images with different virtual image distances.

[0056] In this embodiment, the image generating device mainly includes a projection lens and a projection surface 5. The projection lens is responsible for projecting the image information, and the projection surface 5 is located on the light emitting side thereof and is responsible for receiving and displaying the image information. In the head-up display, the projection surface 5 is used to emit light with image information, which can form a virtual picture on the side of the front windshield of the vehicle away from the human eye after being reflected by the reflection component. Exemplarily, the image generating device also includes a lighting system and a display chip. The type of the image generating device may be, but is not limited to, a DLP type image generating device or an LCOS type image generating device.

[0057] The projection lens includes a fixed lens group 102 and a movable lens group 101. The movable lens group 101 can move along the optical axis relative to the fixed lens group 102. Figure 2 Arrow direction or Figure 7 In the direction indicated by the arrow). Exemplarily, the movable lens group 101 may be the lens group closest to the projection plane 5, or the movable lens group 101 may be the lens group farthest from the projection plane 5, or the movable lens group is located in the middle of all the lenses of the projection lens (in this case, the movable lens group is located between two fixed lens groups). Wherein, no matter where the movable lens group 101 is located in the projection lens, as long as the position of the projection plane 5 can be adjusted within the projection distance range, the display quality of the image displayed on the projection plane 5 can be compensated by the movement of the movable lens group 101, that is, by moving the position of the movable lens group 101, the quality of the image displayed on the projection plane 5 can be improved, thereby improving the quality of the virtual image projected by the HUD.

[0058] Preferably, refer to Figure 2 and Figure 7 In the projection lens, in order to facilitate the movement of the movable lens group 101 and to better improve the quality of the image displayed on the projection surface 5 by moving the movable lens group 101, the movable lens group 101 can be the lens group closest to the projection surface 5, or the movable lens group 101 can be the lens group farthest from the projection surface 5.

[0059] During the movement of the movable lens group 101 along the optical axis of the projection lens, the projection lens achieves zooming. To ensure the clarity of the image displayed on the projection surface 5, the position of the projection surface 5 is adjusted within the projection distance range so that a high-definition image can be displayed on the projection surface 5 during the focusing process of the projection lens.

[0060] Since the position of the projection surface 5 changes due to the movement of the movable lens group 101, the distance between the projection surface 5 and the reflective component in the head-up display is indirectly adjusted. When the distance between the projection surface 5 and the reflective component in the head-up display is adjusted, the transmission path of the light emitted from the projection surface 5 and the incident angle of the light emitted are changed, so that the head-up display can project virtual images with different virtual image distances. Figure 1 and Figure 6 , the setting position of the projection surface 5 moves from position A to position B, and the virtual image distance of the virtual picture projected by the head-up display gradually increases; or the setting position of the projection surface 5 moves from position B to position A, and the virtual image distance of the virtual picture projected by the head-up display gradually shortens.

[0061] Specifically, in the process of the movable lens group 101 moving along the optical axis of the projection lens, the projection surface 5 will approach or move away from the projection lens. According to the imaging law, when the projection surface 5 is close to the projection lens, that is, the projection surface 5 will also be away from the reflective component of the head-up display, the virtual image presented on the windshield will be farther away from the driver (the virtual image distance is farther); when the projection surface 5 is away from the projection lens, that is, the projection surface 5 is close to the reflective component of the head-up display, the virtual image presented on the windshield will be closer to the driver (the virtual image distance is shorter), so that the driver can adjust the distance of the virtual image presented on the windshield according to his own driving habits and driving road conditions.

[0062] Exemplarily, the movable lens group 101 can be continuously moved along the optical axis of the projection lens, and the position of the projection surface 5 (i.e., the projection surface) of the image generating device also changes continuously, so that the head-up display can project continuous virtual images, and the continuously appearing virtual images have different virtual image distances.

[0063] Therefore, in this embodiment, the projection lens in the image generating device includes a movable lens group 101, and the movable lens group 101 can move along the optical axis of the projection lens, and the projection surface 5 can adjust its setting position within the projection distance range. On the one hand, it can ensure that the projection surface 5 displays a high-definition image. On the other hand, the image generating device is applied to a head-up display, and the head-up display can project virtual images with different virtual image distances.

[0064] In a specific embodiment, the position of the movable lens group 101 in the projection lens is limited. Specifically, refer to Figure 1 and Figure 2, the movable lens group 101 is located at the light-emitting side of the fixed lens group 102. Figure 6 and Figure 7 The movable lens group 101 is located at the light incident side of the fixed lens 10 , that is, the fixed lens group 102 is located at the light emitting side of the movable lens group 101 .

[0065] In one example, refer to Figure 1 and Figure 2 In the image generating device, the movable lens group 101 and the projection surface 5 are arranged relative to each other, so that the setting of the projection surface 5 can be adjusted within the projection distance range through the flexible movement of the movable lens group 101 (the actual projection distance between the projection surface 5 and the projection lens is within the projection distance range), so that the projection surface 5 can display a picture with higher definition. The projection distance range is related to the type of the image generating device and the parameters such as the virtual image distance of the virtual picture that the head-up display needs to project. That is to say, in this embodiment, the movable lens group 101 is arranged after the fixed lens group 102, that is, the light first passes through the fixed lens group 102 and then passes through the movable lens group 101. This arrangement can be used to adjust the focus or direction of the light so that the projection surface 5 can display a clear picture within the projection distance range.

[0066] In another example, refer to Figure 6 and Figure 7 In the image generating device, the movable lens group 101 is actually arranged opposite to the equivalent prism 31 in the projection lens, that is, the movable lens group 101 is arranged before the fixed lens group 102, that is, the light first passes through the movable lens group 101, and then passes through the fixed lens group 102. This arrangement is used to pre-process the light through the movable lens group 101 before the light enters the fixed lens group, such as adjusting the angle or intensity of the light, so that the light emitted by the projection lens is projected onto the projection surface 5, and the projection surface 5 displays a clear picture within the projection distance range.

[0067] In one embodiment, referring to Figure 1 and Figure 2 as well as Figure 6 and Figure 7 The lens of the movable lens group 101 that is farthest from the fixed lens group 102 is an aspherical lens.

[0068] Specifically, in the projection lens, the lens closest to the projection surface 5 is an aspherical lens, and the lens farthest from the projection surface 5 is an aspherical lens. By optimizing the curved surface shape, the aspherical lens can focus light more effectively and reduce or eliminate aberrations, including spherical aberration, chromatic aberration, etc., thereby providing higher quality images.

[0069] In addition, when the lens of the projection lens closest to the projection surface 5 is an aspherical lens, and the lens of the projection lens farthest from the projection surface 5 is an aspherical lens, the movable lens group 101 is set on the light-emitting side or the light-incoming side of the fixed lens group 102, that is, by adjusting the setting position of the movable lens group 20 including the aspherical lens, and coordinating the adjustment of the position of the projection surface 5, the head-up display can project virtual images with different virtual image distances while ensuring that the projection surface 5 displays a high-definition image.

[0070] In one embodiment, referring to Figure 1 and Figure 2 The movable lens group 101 is located at the light-emitting side of the fixed lens group 102 , the overall optical power of the movable lens group 101 is negative, and the overall optical power of the fixed lens group 102 is positive.

[0071] In this embodiment, when the movable lens group 101 in the projection lens moves along the optical axis, the position of the projection surface 5 of the image generating device will change. By limiting the overall optical focal length of the movable lens group 101 and the overall optical focal length of the fixed lens group 102, it can be ensured that the actual projection distance between the projection lens and the projection surface 5 is within the projection distance range, and the projection surface 5 can be clearly projected.

[0072] Specifically, the optical power of the movable lens group 101 is negative as a whole, and the movable lens group 101 has the characteristic of diverging light. In a projection lens, a lens group with negative optical power is usually used to adjust the focal length or correct aberrations.

[0073] Due to the negative optical power characteristic of the movable lens group 101, when the movable lens group 101 moves along the optical axis, the divergence degree of the light passing through the movable lens group 101 is changed, thereby affecting the focal length and clarity of the projected image.

[0074] The fixed lens group 102 has a positive focal length, and the fixed lens group 102 as a whole has the characteristic of converging light. In a projection lens, a lens group with a positive focal length is usually used to focus light to a specific position, such as the projection surface 5 (ie, the projection surface).

[0075] In the projection lens, the combination of the movable lens group 101 and the fixed lens group 102 can adjust the projection distance and clarity. When the movable lens group 101 moves along the optical axis, it changes the total focal length of the projection lens and the total length of the lens group inside the lens, thereby affecting the position and size of the projected image on the projection surface. By limiting the optical focal length of the movable lens group 101 and the fixed lens group 102 and the relative position between them, it can be ensured that the projection lens can clearly project the image within the projection distance range.

[0076] In another embodiment, referring to Figure 6 and Figure 7 The fixed lens group 102 is located at the light-emitting side of the movable lens group 101 , the overall optical power of the movable lens group 101 is positive, and the overall optical power of the fixed lens group 102 is negative.

[0077] In this embodiment, the movable lens group 101 has positive focal length, and the movable lens group 101 converges light. In a projection lens, the movable lens group 101 with positive focal length is usually used for zooming, focusing adjustment or aberration correction. Since the movable lens group 101 is movable, it can be moved to adapt to different projection requirements, such as changing the projection distance, and the projection surface 5 displays a clear picture within the projection distance range.

[0078] The fixed lens group 102 has negative optical power and diverges light. In a projection lens, the fixed lens group 102 with negative optical power is usually used to further correct aberrations, adjust light distribution, or achieve a specific projection effect. Since the fixed lens group 10 is fixed, it provides stable optical performance, which helps to ensure the clarity and quality of the projected image.

[0079] In one embodiment, the projection distance between the projection surface 5 and the projection lens is in the range of 120 mm ≤ T ≤ 140 mm.

[0080] Specifically, the range of the projection distance between the projection surface 5 and the projection lens is limited, that is, within this projection distance range, the movable lens group 101 of the projection lens moves along the optical axis to ensure the clarity requirement of the image displayed on the projection surface 5 .

[0081] Exemplarily, based on the type of image generating device, the projection distance range between the projection surface 5 and the projection lens can be limited. Taking DLP as an example, the projection distance range of DLP can be limited according to the effective focal length of the projection lens, the screen size and the DLP chip size requirements, and the projection distance range between the projection surface 5 and the projection lens can be limited according to the projection distance range of DLP.

[0082] The projection distance range of 120mm to 140mm meets the product requirements of most image generating devices and can be applied to head-up displays to achieve close-range virtual image display (for example, about 4.5m) or even virtual image display at a distance of 20m (long-range virtual image display).

[0083] Further, on the basis that the projection distance T between the projection surface 5 and the projection lens satisfies the above range, the movable lens group 101 is located on the light-emitting side of the fixed lens group 102, and the distance T1 between the movable lens group 101 and two adjacent lenses in the fixed lens group 102 satisfies: 3.15 mm <T1<3.35mm。

[0084] In this embodiment, the distance T1 between two adjacent lenses in the movable lens group 101 and the fixed lens group 102 determines the imaging quality of the projection lens to a certain extent. During the movement of the movable lens group 101 along the optical axis, the distance T1 between two adjacent lenses in the movable lens group 101 and the fixed lens group 102 satisfies: 3.15mm < T1 < 3.35mm, which can ensure the clarity, contrast, and color restoration of the projection screen to a certain extent.

[0085] In addition, the two parameters, namely the projection distance T between the projection lens and the projection surface 5 and the distance T1 between two adjacent lenses in the movable lens group 101 and the fixed lens group 102, jointly affect the performance of the image generating device. The projection distance T mainly determines the size and clarity of the projection screen, while T1 has more influence on the imaging quality and stability inside the projection lens. With the combination of the two, the clarity requirement of the display screen on the projection surface 5 can be ensured.

[0086] In another embodiment, referring to Figure 6 and Figure 7 , the projection lens further includes an equivalent prism 31. The movable lens group 101 is located on the light-emitting side of the equivalent prism 31. On the basis that the projection distance T between the projection surface 5 and the projection lens satisfies the above range, the distance T2 between the lens in the movable lens group 101 that is farthest from the fixed lens group 102 and the equivalent prism satisfies: 5.5mm < T2 < 5.9mm.

[0087] In this embodiment, during the movement of the movable lens group 101 along the optical axis, the distance T2 between the lens in the movable lens group 101 that is farthest from the fixed lens group 102 and the equivalent prism 31 satisfies: 5.5mm < T2 < 5.9mm, which can ensure the clarity, contrast, and color restoration of the projection screen to a certain extent.

[0088] Under the condition of comprehensively considering the limiting conditions of T and T2, on the one hand, it ensures that the projection surface 5 displays a high-clarity picture, and on the other hand, the head-up display can project virtual pictures with different virtual image distances.

[0089] Please continue to refer to Figure 6 and Figure 7 , on the basis that the projection distance T between the projection surface 5 and the projection lens satisfies the above range, the distance T3 between two adjacent lenses in the movable lens group 101 and the fixed lens group 102 satisfies: 0.01mm < T3 < 0.2mm.

[0090] In this embodiment, during the movement of the movable lens group 101 along the optical axis, the distance T3 between the movable lens group 101 and two adjacent lenses in the fixed lens group 102 has a direct impact on the optical performance of the projection lens. Too small T3 may lead to enhanced mutual influence between lenses, increase the generation of aberrations and stray light; while too large T3 may increase the overall length of the lens, which is not conducive to compact design. Therefore, based on the projection distance T between the projection surface 5 and the projection lens, T3 is limited to this range, which, on the one hand, ensures that the projection surface 5 displays a higher definition picture, and on the other hand, the head-up display can project virtual pictures with different virtual image distances.

[0091] In one embodiment, the lens aperture of the projection lens closest to the projection surface 5 is D1, and the effective focal length of the projection lens is EFL, wherein D1 / EFL<0.95.

[0092] In this embodiment, D1 generally refers to the effective light diameter of the lens of the projection lens closest to the projection surface 5. This parameter directly affects the light collection capability and imaging quality of the projection lens. A larger aperture generally collects more light, but in some cases also increases the volume and weight of the projection lens.

[0093] The effective focal length (EFL) of the projection lens is the distance from the back focus of the projection lens to the clear imaging point on the projection surface 5 (ie, the projection plane).

[0094] Specifically, by controlling the ratio of D1 / EFL to be less than 0.95, the smaller aperture D1 relative to the longer effective focal length EFL can reduce the diameter of the front end of the lens, thereby saving space and achieving the purpose of reducing the volume of the projection lens system head.

[0095] In one embodiment, the total length of the projection lens is TTL, and the effective focal length of the projection lens is EFL, wherein TTL / EFL<4.5.

[0096] In this embodiment, TTL refers to the total length of the lens, that is, the distance from the front end of the projection lens to the imaging surface (such as the photosensitive element). It includes the space occupied by all lenses, lens barrels and other optical elements inside the lens.

[0097] By setting TTL / EFL<4.5, the overall length of the projection lens can be controlled to a certain extent to achieve the purpose of compact design. In addition, while controlling the length, TTL / EFL<4.5 also helps to optimize the performance of the projection lens. Through reasonable optical design and material selection, good imaging quality and color reproduction can be achieved in a smaller lens volume. In addition, a smaller TTL / EFL ratio can also reduce the aberration and distortion inside the lens, thereby improving the clarity and accuracy of the projected image.

[0098] In one embodiment, referring to Figure 2 and Figure 7 The projection lens further includes an adjustment mechanism 4, and the ineffective area of ​​the lens in the movable lens group 101 is arranged on the adjustment mechanism 4, and the adjustment mechanism 4 drives the movable lens group 101 to move along the optical axis of the projection lens.

[0099] In this embodiment, the ineffective area of ​​the lens in the movable lens group 101 is connected to the adjustment mechanism 4 , and the movable lens group 101 is moved along the optical axis through the adjustment mechanism 4 .

[0100] The effective area of ​​the lens refers to the part that can participate in imaging and contribute to the projection quality. The ineffective area refers to the part of the lens other than the effective area, which usually does not directly participate in imaging. Exemplarily, the ineffective area of ​​the lens in the movable lens group 101 is connected to at least a part of the adjustment mechanism 4, and the movable lens group 101 does not affect the imaging of the projection lens when it moves along the optical axis.

[0101] Exemplarily, the adjustment mechanism 4 drives the movable lens group 101 to move along the optical axis of the projection lens (i.e., the central axis of the lens through which the light passes) by mechanical transmission, electromagnetic drive, etc. This movement can change the position of the projection surface 5 (projection surface) within the projection distance range, thereby adjusting the incident angle of the light emitted from the projection surface 5 to the reflective component. According to the different incident angles of the light emitted from the projection surface 5, the head-up display can project virtual images with different virtual image distances.

[0102] In a specific embodiment, referring to Figure 2 and Figure 7 The adjusting mechanism 4 includes a main body 41, and a concave groove is formed on the side of the main body 41 facing the movable lens group 101, and a sliding groove is formed in the concave groove;

[0103] The adjustment mechanism 4 further includes a sliding portion 42, the inactive area of ​​the lens in the movable lens group 101 is connected to the sliding portion 42, the sliding portion 42 is at least partially located in the recessed groove, and the sliding portion 42 is embedded in the sliding groove to drive the movable lens group 101 to move along the optical axis of the projection lens.

[0104] In this specific embodiment, when the position of the movable lens group 101 needs to be adjusted, the adjustment mechanism 4 drives the sliding part 42 to move in the sliding groove by manual adjustment or electric drive, etc. The movement of the sliding part 42 drives the movable lens group 101 connected thereto to move along the optical axis of the projection lens.

[0105] When the movable lens group 101 moves along the optical axis driven by the sliding part 42, the projection surface 5 adjusts its setting position according to the movement of the movable lens group 101, that is, the position of the projection surface in the image generating device changes. When the position of the projection surface in the image generating device changes, that is, the distance between the projection surface and the reflective component in the head-up display is adjusted, so that the incident angle of the light emitted from the projection surface to the reflective component is adjusted. According to the different incident angles of the light emitted from the projection surface 5, the head-up display can project virtual images with different virtual image distances.

[0106] It should be noted that the structure of the adjustment mechanism includes but is not limited to the above structure, as long as the movable lens group 101 can be moved along the optical axis.

[0107] In a specific embodiment, the projection lens includes: a fifth lens 24, a fourth lens 23, a third lens 22, a second lens 21 and a first lens 20 arranged in sequence along the optical axis, the first lens 20 is arranged adjacent to the projection surface 5, and the optical focal lengths of the fifth lens 24, the fourth lens 23, the third lens 22, the second lens 21 and the first lens 20 are: positive, positive, negative, positive, negative; in this embodiment, the total number of lenses in the lens lens is 5.

[0108] Reference Figure 1 and Figure 2 , the first lens 20 is configured to be movable along the optical axis.

[0109] Reference Figure 6 and Figure 7 , the fifth lens 24 is configured to be movable along the optical axis.

[0110] That is to say, for the same set of optical architecture, by moving the position of the first lens 20 (the lens closest to the projection plane 5), or by moving the position of the fifth lens 24 (the lens farthest from the projection plane 5), combined with the adjustment of the position of the projection plane 5 within the projection distance range, on the one hand, it is ensured that the projection plane 5 displays a higher definition image, and on the other hand, the head-up display can project virtual images with different virtual image distances.

[0111] It should be noted that the movable lens group 101 may include one movable lens as defined above, or the movable lens group 101 may also include two movable lenses, or more movable lenses, and the fixed lens group 102 may include four fixed lenses as defined above, or more or less lenses are also acceptable.

[0112] In addition, depending on the type of image generating device, the display size of the projection surface 5, and the requirements for the quality of the image displayed on the projection surface 5, the projection lens may include different numbers of lenses. A smaller number of lenses will reduce manufacturing costs and also help reduce the volume and weight of the projection lens. However, the reduction in the number of lenses will sacrifice some of the imaging quality. Therefore, it is necessary to limit the total number of lenses within an appropriate number range under the premise of ensuring a certain imaging quality. For example, the number of lenses may be 4 to 7.

[0113] It should be noted that the embodiment of the present application does not specifically limit the number of lenses in the projection lens, as long as the HUD can project a clear virtual image with specific different virtual image distances by moving the position of a lens in combination with the setting position of the projection surface.

[0114] In a specific embodiment, referring to Figure 1 and Figure 2 The movable lens group 101 includes a lens movable along the optical axis, namely, the first lens 20. The optical power of the first lens 20 is negative, and the lens has a divergent effect on light. In a projection lens, a lens with negative optical power is usually used to adjust the focal length to meet different projection requirements.

[0115] Specifically, the first lens 20 moves along the optical axis to achieve zoom, focus or other optical adjustment functions of the projection lens. That is, when the first lens 20 moves along the optical axis, the projection surface 5 moves within the projection distance range to ensure the quality of the image displayed on the projection surface 5. When the projection surface 5 moves within the projection distance range, the incident angle of the light emitted by the projection surface 5 to the reflective component of the head-up display will change, so that the head-up display can project virtual images with different virtual image distances on the side of the front windshield away from the human eye.

[0116] The fixed lens group 102 includes four lenses, specifically the second lens 21, the third lens 22, the fourth lens 23 and the fifth lens 24. The transmission direction of the light is: the light emitted by the illumination system passes through the display chip, passes through the fifth lens 24, the fourth lens 23, the third lens 22, the second lens 21 and the first lens 20 in sequence, and then is projected to the projection surface 5.

[0117] The fifth lens 24 and the fourth lens 23 both have positive focal lengths, which help to enhance the convergence of light and improve the clarity and contrast of the projected image. At the same time, the fourth lens 23 and the third lens 22 can be glued together to correct the aberration generated by the fifth lens 24 to ensure the quality of the projected image.

[0118] The third lens 22 is located on the light-emitting side of the fourth lens 23, and the optical power of the third lens 22 is negative. A lens with negative optical power is used to further adjust the path and distribution of light to optimize the imaging quality and reduce aberration. Exemplarily, by reasonably designing the curvature and material of the third lens 22, optimized control of light can be achieved.

[0119] The second lens 21 is arranged adjacent to the first lens 20. The second lens 21 is located on the light-emitting side of the third lens 22, and the optical power of the second lens 21 is positive. A lens with positive optical power has a further converging effect on light, which helps to focus the light onto the projection surface 5 to form a clear image.

[0120] Exemplarily, on the basis that the projection distance T between the projection surface 5 and the projection lens satisfies 120 mm to 140 mm, the distance T1 between the first lens 20 and the second lens 21 satisfies: 3.15 mm < T1 < 3.35 mm. That is, by finely adjusting the setting position of the first lens 20, the position of the projection surface 5 changes within the projection distance range. On the basis of achieving clear projection, the head-up display can project images with different virtual image distances.

[0121] In addition, a diaphragm 34 is also provided between the second lens 21 and the third lens 22.

[0122] In addition, the projection lens further includes an equivalent prism 31, a protective glass 32, and a DMD 33.

[0123] In a specific embodiment, referring to Figure 6 and Figure 7 , the movable lens group 101 includes a lens that can move along the optical axis, that is, the fifth lens 24. The movement of the fifth lens 24 is usually used for zooming or focusing adjustment. By changing the position of the fifth lens 24, the focal length of the projection lens can be changed to adapt to different projection distances.

[0124] Exemplarily, on the basis that the projection distance T between the projection surface 5 and the projection lens satisfies 120 mm to 140 mm, the distance T3 between the fifth lens 24 and the fourth lens 23 satisfies: 0.01 mm < T3 < 0.2 mm. That is, by finely adjusting the setting position of the fifth lens 24, the position of the projection surface 5 changes within the projection distance range. On the basis of achieving clear projection, the head-up display can project images with different virtual image distances.

[0125] Alternatively, on the basis that the projection distance T between the projection surface 5 and the projection lens satisfies 120 mm to 140 mm, the distance T2 between the fifth lens 24 and the equivalent prism 31 satisfies: 5.5 mm < T2 < 5.9 mm. That is, by finely adjusting the setting position of the fifth lens 24, the position of the projection surface 5 changes within the projection distance range, and on the basis of achieving a clear projection, the head-up display can project images with different virtual image distances.

[0126] In a specific embodiment, referring to Figure 1 and Figure 2 and Figure 6 and Figure 7 the first lens 20 is an aspherical lens, and the fifth lens 24 is an aspherical lens.

[0127] Specifically, the first lens 20, as an aspherical lens disposed opposite to the projection surface 5, can reduce the aberration generated during the zooming and focusing processes, ensuring that the projection image remains clear and accurate at different focal lengths. The fifth lens 24, as the first aspherical lens through which light enters, can more effectively correct the field curvature, ensuring that the projection image remains clear and flat throughout the entire field of view. By selecting aspherical lenses for these two key positions, the imaging quality of the lens can be significantly improved, and the aberration can be reduced.

[0128] When the first lens 20 is an aspherical lens and the fifth lens 24 is an aspherical lens, by moving the position of the first lens 20 or the setting position of the fifth lens 24, on the one hand, it ensures that the projection surface 5 displays a high-definition image, and on the other hand, the head-up display can project virtual images with different virtual image distances.

[0129] In a specific embodiment, the projection lens satisfies: -1.1 < EFL / f1 < -0.95; 0.95 < EFL / f2 < 1.05; -1.25 < EFL / f3 < -1.15; 0.93 < EFL / f4 < 0.98; 0.65 < EFL / f5 < 0.75;

[0130] wherein, EFL is the effective focal length of the projection lens, f1 is the focal length of the first lens 20, f2 is the focal length of the second lens 21, f3 is the focal length of the third lens 22, f4 is the focal length of the fourth lens 23, and f5 is the focal length of the fifth lens 24.

[0131] In this embodiment, by limiting the ratio of the focal length of each lens to the effective focal length of the projection lens, the light trend of the projection lens can be made smoother, the resolution of the projection lens can be improved, and the performance stability of the projection lens can be ensured.

[0132] In addition, in another embodiment, the refractive index and Abbe number of the material of the first lens 20 satisfy the relationship: Nd1<1.65, Vd1>45; the refractive index and Abbe number of the material of the second lens 21 satisfy the relationship: Nd2<1.75, Vd2<45; the refractive index and Abbe number of the material of the third lens 22 satisfy the relationship: Nd3<1.75, Vd3<45; the refractive index and Abbe number of the material of the fourth lens 23 satisfy the relationship: Nd4>1.65, Vd4>45; the refractive index and Abbe number of the material of the fifth lens 24 satisfy the relationship: Nd5<1.65, Vd5>45. The combination of the above materials can reduce the chromatic aberration of the projection lens.

[0133] In one embodiment, the third lens 22 and the fourth lens 23 are cemented to form a cemented lens group.

[0134] In this embodiment, the cemented lens group can more effectively correct aberrations generated by a single lens, such as chromatic aberration, spherical aberration, etc., by combining lenses made of different materials.

[0135] The specific combination of the focal length ratio and the optical power (one is negative and the other is positive) of the third lens 22 and the fourth lens 23 enables them to form a more precise control of light after gluing, thereby optimizing the imaging quality.

[0136] In a specific embodiment, referring to Figure 1 and Figure 2 The projection lens of the image generating device includes, in order along the light emitting direction: DMD 33, protective glass 32, equivalent prism 31, fifth lens 24, fourth lens 23, third lens 22, aperture 34, second lens 21 and first lens 20, wherein the first lens 20 is movable along the optical axis direction. The setting position of the projection surface 5 is adjustable within the range of the variable projection area. Table 1 shows the optical parameters of the projection lens.

[0137] Table 1:

[0138]

[0139] The first lens 20 and the fifth lens 24 are aspherical lenses, wherein S1, S2 and S9, S10 are two aspherical surfaces of the first lens 20 and the fifth lens 24, and the surface shapes are described as follows:

[0140]

[0141] Among them, Z(h) is the vector height of the aspheric surface at a height of h along the optical axis and the distance from the vertex of the aspheric surface, where c = 1 / r, r represents the radius of curvature of the aspheric surface, k is the cone coefficient conic, and A, B, C, D, E, F, G, and H are the high-order coefficients of the aspheric surface.

[0142] Table 2 provides aspheric parameters of the first lens 20 and the fifth lens 24 in the projection lens in the embodiment:

[0143] Table 2:

[0144] Surface number K A B C D E F G H S1 50.24 0 -6.9E-04 2.2E-05 -7.5E-07 1.0E-08 -1.0E-10 0 0 S2 -6.15 0 3.6E-03 -2.6E-04 1.6E-05 -5.8E-07 9.3E-09 0 0 S9 -5.10 0 3.1E-05 5.6E-07 -2.2E-08 -1.5E-11 0.0E+00 0 0 S10 -2.74 0 6.4E-06 7.0E-07 -2.2E-08 -2.3E-11 0.0E+00 0 0

[0145] In this specific embodiment, the projection lens in the image generating device can clearly project in the projection distance region between 120 mm and 140 mm.

[0146] in Figure 3a to Figure 3e Shown are the MTF diagrams of the projection lens of the image generating device provided in an embodiment of the present application when the projection distances are 120mm, 125mm, 130mm, 135mm and 140mm. When the projection distances are 120mm, 125mm, 130mm, 135mm and 140mm respectively, the projection lens can achieve clear projection.

[0147] in Figure 4a to Figure 4e Shown is the field curvature / distortion diagram of the projection lens of the image generating device provided in an embodiment of the present application when the projection distance is 120mm, 125mm, 130mm, 135mm and 140mm. When the projection distance is 120mm, 125mm, 130mm, 135mm and 140mm, the image field curvature / distortion is small and the picture has a higher quality.

[0148] in Figure 5 The figure shows a curve diagram of the change in position of the first lens 20 relative to the second lens 21 when the projection distance of the projection lens of the image generating device provided in the embodiment of the present application changes by 2 mm at a time from 120 mm to 140 mm. When the position of the first lens 20 is finely adjusted along the optical axis, within the projection distance range, the image displayed on the projection surface 5 has a higher image quality.

[0149] In another specific embodiment, referring to Figure 6 and Figure 7 The projection lens of the image generating device includes, in order along the light emission direction: DMD 33, protective glass 32, equivalent prism 31, fifth lens 24, fourth lens 23, third lens 22, aperture 34, second lens 21 and first lens 20, wherein the fifth lens 24 is movable along the optical axis direction. The setting position of the projection surface 5 is adjustable within the range of the variable projection area. Table 3 shows the optical parameters of the projection lens.

[0150] Table 3:

[0151]

[0152] The first lens 20 and the fifth lens 24 are aspherical lenses, wherein S1, S2 and S9, S10 are two aspherical surfaces of the first lens 20 and the fifth lens 24, and the surface shapes are described as follows:

[0153]

[0154] Among them, Z(h) is the vector height of the aspheric surface at a height of h along the optical axis and the distance from the vertex of the aspheric surface, where c = 1 / r, r represents the radius of curvature of the aspheric surface, k is the cone coefficient conic, and A, B, C, D, E, F, G, and H are the high-order coefficients of the aspheric surface.

[0155] Table 4 provides aspheric parameters of the first lens 20 and the fifth lens 24 in the projection lens in the embodiment:

[0156] Table 4:

[0157] Surface number K A B C D E F G H S1 50.24 0 -6.9E-04 2.2E-05 -7.5E-07 1.0E-08 -1.0E-10 0 0 S2 -6.15 0 3.6E-03 -2.6E-04 1.6E-05 -5.8E-07 9.3E-09 0 0 S9 -5.10 0 3.1E-05 5.6E-07 -2.2E-08 -1.5E-11 0.0E+00 0 0 S10 -2.74 0 6.4E-06 7.0E-07 -2.2E-08 -2.3E-11 0.0E+00 0 0

[0158] In this specific embodiment, the projection lens in the image generating device can clearly project in the projection distance region between 120 mm and 140 mm.

[0159] in Figure 8a to Figure 8e Shown are the MTF diagrams of the projection lens of the image generating device provided in an embodiment of the present application when the projection distances are 120mm, 125mm, 130mm, 135mm and 140mm. When the projection distances are 120mm, 125mm, 130mm, 135mm and 140mm respectively, the projection lens can achieve clear projection.

[0160] in Figure 9a to Figure 9e Shown is the field curvature / distortion diagram of the projection lens of the image generating device provided in an embodiment of the present application when the projection distance is 120mm, 125mm, 130mm, 135mm and 140mm. When the projection distance is 120mm, 125mm, 130mm, 135mm and 140mm, the image field curvature / distortion is small and the picture has a higher quality.

[0161] in Fig.10 The figure shows a curve chart of the change in the position of the fifth lens 24 relative to the equivalent prism 31 when the projection distance of the projection lens of the image generating device provided by the embodiment of the present application changes by 2 mm at a time from 120 mm to 140 mm. When the position of the fifth lens 24 is finely adjusted along the optical axis, within the projection distance range, the picture displayed on the projection surface 5 has a higher picture quality.

[0162] The embodiment of the present application also provides a head-up display. The head-up display includes the image generating device as described above. The image generating device is applied to the head-up display, and the head-up display can project virtual images with different virtual image distances while achieving clear projection images.

[0163] The above embodiments focus on the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. Considering the simplicity of the text, they will not be repeated here.

[0164] Although some specific embodiments of the present application have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are only for illustration, not for limiting the scope of the present application. It should be understood by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. An image generating device, characterized in that: Applied to a head-up display, the image generating device comprises: a projection lens and a projection surface (5) located on the light-emitting side of the projection lens; The projection lens comprises a fixed lens group (102) and a movable lens group (101); the movable lens group (101) is movable along the optical axis of the projection lens, and the position of the projection surface (5) is adjusted according to a projection distance range, so that the head-up display projects virtual images with different virtual image distances.

2. The image generating device according to claim 1, characterized in that: The movable lens group (101) is located on the light-emitting side of the fixed lens group (102), or the movable lens group (101) is located on the light-incoming side of the fixed lens group (102).

3. The image generating device according to claim 2, characterized in that: The lens of the movable lens group (101) that is farthest from the fixed lens group (102) is an aspherical lens.

4. The image generating device according to claim 2, characterized in that: The movable lens group (101) is located on the light-emitting side of the fixed lens group (102); the overall optical power of the movable lens group (101) is negative, and the overall optical power of the fixed lens group (102) is positive.

5. The image generating device according to claim 2, characterized in that: The movable lens group (101) is located on the light incident side of the fixed lens group (102); the overall optical focal length of the movable lens group (101) is positive, and the overall optical focal length of the fixed lens group (102) is negative.

6. The image generating device according to claim 1, characterized in that: The projection distance range between the projection surface (5) and the projection lens satisfies: 120 mm ≤ T ≤ 140 mm.

7. The image generating device according to claim 6, characterized in that: The movable lens group (101) is located on the light-emitting side of the fixed lens group (102), and the distance T1 between the movable lens group (101) and two adjacent lenses in the fixed lens group (102) satisfies: 3.15 mm <T1<3.35mm。 8. The image generating device according to claim 6, characterized in that: The projection lens further comprises an equivalent prism (31), the movable lens group (101) is located at the light-emitting side of the equivalent prism (31), and the distance T2 between the lens in the movable lens group (101) farthest from the fixed lens group (102) and the equivalent prism satisfies: 5.5 mm <T2<5.9mm。 9. The image generating device according to claim 6, characterized in that: The movable lens group (101) is located on the light incident side of the fixed lens group (102), and the distance T3 between the movable lens group (101) and two adjacent lenses in the fixed lens group (102) satisfies: 0.01 mm <T3<0.2mm。 10. The image generating device according to claim 1, characterized in that: The lens aperture of the projection lens closest to the projection surface (5) is D1, and the effective focal length of the projection lens is EFL, wherein D1 / EFL<0.

95.

11. The image generating device according to claim 1, characterized in that: The total length of the projection lens is TTL, and the effective focal length of the projection lens is EFL, wherein TTL / EFL<4.

5.

12. The image generating device according to claim 1, characterized in that: The projection lens further comprises an adjustment mechanism (4), an ineffective area of ​​the lens in the movable lens group (101) is arranged on the adjustment mechanism (4), and the adjustment mechanism (4) drives the movable lens group (101) to move along the optical axis of the projection lens.

13. The image generating device according to claim 12, characterized in that: The adjustment mechanism (4) comprises a main body (41), a concave groove is formed on a side of the main body (41) facing the movable lens group (101), and a sliding groove is provided in the concave groove; The adjustment mechanism (4) further comprises a sliding portion (42), an ineffective area of ​​a lens in the movable lens group (101) is connected to the sliding portion (42), at least a portion of the sliding portion (42) is located in the recessed groove, and the sliding portion (42) is embedded in the sliding groove to drive the movable lens group (101) to move along the optical axis of the projection lens.

14. The image generating device according to any one of claims 1 to 13, characterized in that: The projection lens comprises: a fifth lens (24), a fourth lens (23), a third lens (22), a second lens (21) and a first lens (20) which are arranged in sequence along an optical axis; the first lens (20) is arranged adjacent to the projection surface (5); the optical powers of the fifth lens (24), the fourth lens (23), the third lens (22), the second lens (21) and the first lens (20) are: positive, positive, negative, positive, negative; the first lens (20) is configured to be movable along the optical axis, or the fifth lens (24) is configured to be movable along the optical axis.

15. The image generating device according to claim 14, characterized in that: The projection distance range between the first lens (20) and the projection surface (5) satisfies 120 mm ≤ T ≤ 140 mm.

16. The image generating device according to claim 14, characterized in that: The first lens (20) is an aspherical lens, and the fifth lens (24) is an aspherical lens.

17. The image generating device according to claim 15, characterized in that: When the first lens (20) is configured to be movable along the optical axis, the distance T1 between the first lens (20) and the second lens (21) satisfies: 3.15 mm <T1<3.35mm。 18. The image generating device according to claim 15, characterized in that: When the fifth lens (24) is configured to be movable along the optical axis, the distance T3 between the fifth lens (24) and the fourth lens (23) satisfies: 0.01 mm <T3<0.2mm。 19. The image generating device according to claim 15, characterized in that: The projection lens further comprises an equivalent prism (31), and when the fifth lens (24) is configured to be movable along the optical axis, a distance T2 between the fifth lens (24) and the equivalent prism (31) satisfies: 5.5 mm <T2<5.9mm。 20. The image generating device according to claim 14, characterized in that: The projection lens meets the following requirements: -1.1 <EFL / f1<-0.95;0.95<EFL / f2<1.05;-1.25<EFL / f3<-1.15;0.93<EFL / f4<0.98;0.65<EFL / f5<0.75; Wherein, EFL is the effective focal length of the projection lens, f1 is the focal length of the first lens (20), f2 is the focal length of the second lens (21), f3 is the focal length of the third lens (22), f4 is the focal length of the fourth lens (23), and f5 is the focal length of the fifth lens (24).

21. The image generating device according to claim 14, characterized in that: The third lens (22) and the fourth lens (23) are cemented together to form a cemented lens group.

22. A head-up display, characterized in that: The head-up display comprises an image generating device as claimed in any one of claims 1-21.

Images