Out-of-focus protection desktop far-vision read-write device

Abstract

The utility model discloses an out-of-focus protection desktop far-vision read-write device which comprises a plane spectroscope, a first concave reflector and a second concave reflector. Wherein the light reflected by the table top and an object placed on the table top is emitted to the plane spectroscope from the lower part and then is split; a first light ray formed by reflection of the plane spectroscope is reflected by the first concave reflector, then penetrates through the plane spectroscope and is emitted to an exit pupil position; a second light ray formed after penetrating through the plane spectroscope is reflected by the second concave reflector, is reflected by the plane spectroscope again and then is emitted to an exit pupil position; one of the first light and the second light emitted to the exit pupil position is imaged at a virtual image position not less than 3 meters in front of the exit pupil position, and the other one is imaged at a real image behind the exit pupil position to form positive defocus. According to the out-of-focus protection desktop far-vision read-write device, the coaxial optical system is used, an object placed on a desktop is amplified, projected and imaged, positive out-of-focus stimulation is provided, and myopia prevention and control are achieved.

Description

Technical Field

[0001] The utility model relates to a defocus protection desktop telescopic reading and writing device. Background Art

[0002] At present, the myopia problem among teenagers is becoming increasingly serious. The fundamental reason is that teenagers' eyes focus on a relatively close range most of the time. In order to adapt to close-range imaging, the eye axis gradually becomes longer. In order to solve this problem, various myopia prevention and control products have emerged on the market.

[0003] The zoom lens is one of the many existing myopia prevention and control devices. It mostly uses two free-form surface reflectors to fold the light path, increasing the optical path, and can display closer objects farther away, inhibiting the extension of the viewer's eye axis, achieving the purpose of myopia prevention and control. However, this method also has some problems. Due to the introduction of off-axis optics, asymmetric distortion is brought about. At the same time, it is subject to the limitations of large-aperture free-form surface reflective lens processing technology, and the accuracy of the surface shape is difficult to guarantee, resulting in a decrease in imaging clarity and an aggravation of the pupil swimming phenomenon. These problems have led to a decrease in user experience.

[0004] Moreover, existing telescopes can only provide single-focus distant viewing display, and the human eye stares at a single focal position for a long time during use. For users who already have vision problems, this can only maintain vision, and does not actively intervene in vision recovery. Summary of the invention

[0005] The technical problem to be solved by the utility model is to provide a defocus protection desktop telescopic reading and writing device.

[0006] In order to achieve the above technical objectives, the utility model adopts the following technical solutions:

[0007] A defocus protection desktop telescopic reading and writing device comprises: a plane beam splitter, a first concave reflector and a second concave reflector; wherein the light reflected by the desktop and the object placed on the desktop is directed to the plane beam splitter from below and is split at the position of the plane beam splitter; the first light formed after being reflected by the plane beam splitter is reflected by the first concave reflector, and then passes through the plane beam splitter to be directed to the exit pupil position; the second light formed after passing through the plane beam splitter is reflected by the second concave reflector, and is reflected again by the plane beam splitter to be directed to the exit pupil position; one of the first light and the second light directed to the exit pupil position forms an image at a virtual image position not less than 3 meters in front of the exit pupil position, and the other forms a real image behind the exit pupil position, forming a positive defocus optical path, and the diopter corresponding to the positive defocus optical path is controlled between +1D and +5D.

[0008] Preferably, the first concave reflecting mirror and the second concave reflecting mirror have different curvature radii, wherein the concave reflecting mirror with a smaller curvature radius is used for positive defocus imaging.

[0009] Preferably, a total reflection film is attached to the surface of the concave reflecting mirror used for normal imaging; and a total reflection film is attached to the peripheral area of ​​the concave reflecting mirror used for positive defocus imaging, thereby forming a peripheral defocus light path.

[0010] According to a preferred embodiment of the utility model, a light absorbing material is attached to the surface of the concave reflector used for positive defocus imaging in an area where a total reflection film is not provided.

[0011] According to another preferred embodiment of the utility model, the central area of ​​the concave reflector for positive defocus imaging is also attached with a total reflection film, and a replaceable baffle is arranged between the concave reflector for positive defocus imaging and the plane beam splitter, and the baffle has a predetermined pattern for completely blocking light in the central area and allowing light to pass through the peripheral area to achieve specific display content of the defocus light path.

[0012] Preferably, the central area of ​​the baffle has a pattern of regular or irregular shapes, or is composed of a plurality of regular or irregular shapes spliced ​​into a complete pattern to achieve light shielding.

[0013] Preferably, the peripheral area of ​​the baffle is completely or partially light-transmissive.

[0014] Preferably, a plurality of shielding patterns are discretely or periodically arranged in the peripheral area of ​​the baffle to achieve local light transmission, and the plurality of shielding patterns have the same or different shapes.

[0015] Preferably, the contour of the local light-transmitting area in the peripheral area of ​​the baffle forms a predetermined shape.

[0016] Preferably, the baffle is a light-transmitting plate with a flat or curved surface and no light focality, and the predetermined pattern is attached to the surface of the baffle.

[0017] Preferably, an electro-transmittance variable material is arranged between the beam splitter and the concave reflector for positive defocus imaging to achieve switching or conversion of the defocus mode.

[0018] According to another preferred embodiment of the present invention, surfaces of the first concave reflecting mirror and the second concave reflecting mirror are provided with total reflection films.

[0019] Preferably, the second concave reflector has a smaller radius of curvature and is used to reflect the second light transmitted through the plane reflector.

[0020] Preferably, the curvature radius of the first concave reflecting mirror and the second concave reflecting mirror ranges from 400 mm to 600 mm.

[0021] Preferably, the exit pupil distance is between 150 mm and 300 mm, the exit pupil aperture is not less than φ60 mm, and the field of view angle is not less than 35° and not more than 42°.

[0022] Preferably, the defocus protection desktop telescopic reading and writing device also includes a shell, which includes at least a left side panel and a right side panel, and the left side panel, the right side panel, the plane beam splitter and the lower end of the vertically arranged concave reflector constitute a light inlet for the light reflected by the desktop and the object placed on the desktop to enter.

[0023] Preferably, the housing further comprises a top cover, and the left side plate, the right side plate and the top cover form a light shield.

[0024] Preferably, a fill light is arranged at the lower part of the left side panel and / or the right side panel.

[0025] The defocus protection desktop telescopic reading and writing device provided by the utility model uses a bir db at h coaxial optical system to magnify and project distant images of objects such as books placed on the desktop, achieving an imaging effect similar to that of a telescope. This structure can obtain an almost distortion-free, high-definition picture without introducing a free-form surface, while reducing the difficulty of processing and adjustment. In addition, the defocus protection desktop telescopic reading and writing device introduces a positive defocus optical path, and when the user reads the text and other contents in the book, a positive defocus stimulation is given at the same time, further inhibiting the growth of the eye axis, and at the same time may have a certain effect on the thickening of the choroid, thereby achieving myopia prevention and control. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the overall optical path of the defocus protection desktop telescopic reading and writing device provided by the embodiment of the utility model;

[0027] Figure 2 It is a schematic diagram of the structure of a concave reflector in a positive defocus light path;

[0028] Figure 3 is a schematic diagram of a light path of an embodiment in which a replaceable baffle is provided in a peripheral defocus light path;

[0029] Figure 4a-4d is a schematic diagram of the structure of a baffle having a central area of ​​a regular shape;

[0030] Figure 5a-Figure 5e is a schematic diagram of the structure of a baffle having a central region with irregular edges;

[0031] Figure 6a-6h is a schematic diagram of the structure of a baffle whose central area is circular and whose peripheral area is partially transparent;

[0032] Figure 7aand Figure 7b is a schematic diagram of the structure of a baffle whose central area is square and whose peripheral area is partially transparent;

[0033] Figure 8 is a schematic diagram of the structure of a baffle having a drum-shaped central area and a partially light-transmissive peripheral area;

[0034] Fig. 9 It is a schematic diagram of the structure of a baffle having a predetermined shape in the peripheral light-transmitting area;

[0035] Fig.10 It is a three-dimensional structural diagram of a defocus protection desktop telescopic reading and writing device;

[0036] Fig.11 It is a schematic diagram of the exploded structure of a defocus protection desktop telescopic reading and writing device. DETAILED DESCRIPTION

[0037] The technical solution of the utility model is further described in detail below in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all of the embodiments. It should be noted that the embodiments of the utility model and the features in the embodiments can be combined with each other without conflict.

[0038] The present application aims to provide a desktop telescopic reading and writing device with defocus protection based on a coaxial optical system. Figure 1 As shown, the defocus protection desktop telescopic reading and writing device is implemented based on Birdbath (BB for short) optical path, including two BB optical paths, the two BB optical paths share a plane beam splitter 1, the light reflected by the desktop 4 (and the object placed on the desktop 4, such as a book) is emitted from the bottom to the plane beam splitter 1, and is split at the position of the plane beam splitter 1; the first light formed after reflection by the plane beam splitter 1 is reflected by the first concave reflector 2, and then passes through the plane beam splitter 1 and is emitted to the exit pupil position; the second light formed after passing through the plane beam splitter 1 is reflected by the second concave reflector 3, and is reflected again by the plane beam splitter 1 and is emitted to the exit pupil position; the first light and the second light form different optical paths respectively, the light in the two optical paths are respectively imaged in the human eye, each optical path has an independent focal plane, and the positions of the two focal planes are different.

[0039] Among them, one of the first light and the second light directed to the exit pupil position forms an image at a virtual image position not less than 3 meters in front of the human eye (i.e. in front of the exit pupil position) for normal viewing by the human eye. At this time, the light enters the human eye and forms an image on the retina of the human eye; the other forms a real image on the opposite side of the exit pupil position (i.e. behind the exit pupil position) to form a positive defocus optical path. The visual acuity corresponding to the positive defocus optical path can be controlled between +1D and +5D. The light in the positive defocus optical path forms an image in front of the retina of the human eye after entering the human eye, presenting a myopic defocus state, thereby achieving defocus stimulation and contributing to myopia prevention and control. In the above optical paths, the optical path used for normal human eye imaging can be the optical path formed by the first light or the optical path formed by the second light.

[0040] In order to make the focal plane positions of the two optical paths different, the first concave reflector 2 and the second concave reflector 3 can have the same surface parameters but different distances from the plane beam splitter 1, or the first concave reflector 2 and the second concave reflector 3 can have the same distances from the plane beam splitter 1, but the first concave reflector 2 and the second concave reflector 3 have different curvature radii. Preferably, the first concave reflector 2 and the second concave reflector 3 use different curvature radii, so that the positive defocus display of the dual light paths can be realized in a smaller device. The curvature radius of the first concave reflector 2 and the second concave reflector 3 ranges from 400mm to 600mm. Among them, of the two concave reflectors, the concave reflector with a larger curvature radius is used for normal human eye imaging, and the concave reflector with a smaller curvature radius is used for positive defocus imaging.

[0041] In one embodiment provided by the present invention, the surfaces of the first concave reflector 2 and the second concave reflector 3 are provided with a total reflection film. In other embodiments, in order to avoid mutual interference between the two optical paths as much as possible, the entire surface of the concave reflector provided in the optical path for normal imaging of the human eye is provided with a total reflection film, and the reflective film coating of the concave reflector provided in the optical path for positive defocus imaging of the human eye can be provided in a peripheral coating manner, where the total reflection film is provided only in the peripheral area of ​​the surface, and the reflective film is not provided in the central area, so that in the positive defocus optical path, only the peripheral area is reflected, and the peripheral defocus imaging effect is achieved.

[0042] For example, in Figure 2 In the illustrated embodiment, the first concave reflector 2 with a larger curvature radius is used for normal human eye imaging, and a total reflection film is attached to its entire surface; the second concave reflector 3 with a smaller curvature radius is used for positive defocus imaging, and only the peripheral area 32 is attached to the total reflection film, and the central area 31 is not provided with a total reflection film. Preferably, a light absorbing material can be attached to the central area 31 where the total reflection film is not provided.

[0043] As an alternative way to achieve a defocused light path, only the peripheral area is reflected, such as Figure 3 As shown, the surfaces of the first concave reflector 2 and the second concave reflector 3 can also be provided with a total reflection film at the same time, and a baffle 5 with a predetermined pattern is provided under the second concave reflector 3, the central area of ​​the predetermined pattern is a light-impermeable and blocked area (corresponding to the original central area 31 that is not provided with a reflection film and cannot reflect light), and the peripheral area of ​​the predetermined pattern is fully or partially light-permeable, so as to realize the specific display content of the defocused light path. Compared with the method of providing a total reflection film in different areas on the second concave reflector 3, the baffle with a predetermined pattern can achieve the same effect and is easy to replace, and the baffle 5 can be conveniently inserted and replaced through a groove or other fixing method.

[0044] The surface shape of the baffle 5 can be varied; the baffle 5 can be a light-transmitting plate of equal thickness with a flat or curved surface to avoid introducing additional optical power into the defocused light path, and a light-shielding material is arranged on its surface to form a predetermined pattern. The surface shape of the baffle can be a plane, a cylinder or a spherical surface, so that the shape of the baffle is close to the surface shape of the second concave reflector 3.

[0045] An electro-transmittance variable material is arranged between the beam splitter 1 and the second concave reflector 3 to realize the switch or change of the defocus mode. The electro-transmittance variable material can be arranged on the surface of the baffle 5 or the second concave reflector 3 to form a switch. The electro-transmittance variable material can be realized by one or more methods such as atomized film, liquid crystal, electrochromic, etc., and the frequency of the switch is set to increase the stimulation. Preferably, the baffle can be a composite liquid crystal panel to realize dynamic defocus switching and mode setting (timing switching), and the pattern can also be multi-grayscale gradient.

[0046] Different schematic baffle patterns are as follows Figure 4a-4d As shown, the black area indicates the area where the light is blocked, and the white area indicates the area where the light passes, that is, the predetermined pattern on the baffle is implemented as a central area for complete light blocking, and the peripheral area allows light to pass. It is not limited to this, and there may be other patterns, such as Figure 5a-Figure 9 shown.

[0047] Specifically, if Figure 4a to Figure 4d As shown, the central area of ​​the baffle has a regular shape, such as a circle, square, pentagon, hexagon, ellipse, or other axially symmetrical or centrally symmetrical shape; Figure 5a to Figure 5c As shown, the central area of ​​the baffle has an irregular shape, and the outline of the central area of ​​the baffle is a shape of a combination of straight lines or curves; Figure 5d and Figure 5e As shown, the central area of ​​the baffle is composed of multiple regular or irregular shapes spliced ​​into a complete pattern to achieve light shielding, for example, Figure 5d and Figure 5e They are Figure 5aThe patterns shown are different combinations of patterns formed by non-periodic tiling of units. Figure 5d and Figure 5e In the figure, the white lines in the center area are used to illustrate the stitching lines for understanding the pattern stitching, not to indicate light transmission. Figure 5e Although a hollow light-transmitting area is partially provided near the periphery of the central area, it does not hinder the full shielding effect of the central area. Figures 4a to 5e In the embodiment, the area of ​​the central region of the baffle 5 can be large or small, and the peripheral region of the baffle 5 is completely light-transmissive.

[0048] In addition, if Figures 6a to 7b As shown, the predetermined pattern on the baffle 5 is implemented as a central area completely blocking light, and a portion of the peripheral area is blocked and a portion of the peripheral area allows light to pass. The shape of the central area of ​​the baffle 5 can be as follows Figures 4a-4d The regular shapes such as circle, square, etc. shown in FIG. Figure 5a-5e The irregular shape shown; the peripheral area of ​​the baffle 5 is partially blocked to achieve local light transmission, wherein the blocking pattern can be an independent pattern, the blocking pattern can also be a plurality of blocking patterns arranged discretely or periodically, and the plurality of blocking patterns have the same or different shapes.

[0049] like Figure 6a to Figure 6h As shown in FIG. 1 , the central area of ​​the baffle is circular in shape, and the peripheral area is partially blocked. Specifically, Figures 6a to 6d As shown, the peripheral area of ​​the baffle 5 is arranged with a plurality of circular shielding patterns, and the plurality of circles are arranged in a plurality of ways such as in a row, in a cluster, in a radial shape or in a ring shape, and the number of distribution of the plurality of patterns is not limited. Figure 6e In the embodiment, the peripheral area of ​​the baffle 5 is provided with an annular shielding area, and the area outside the shielding ring in the peripheral area is light-transmissive. Figure 6f and Figure 6g As shown, a plurality of hexagonal shielding patterns are arranged in the peripheral area of ​​the baffle 5, and the plurality of hexagons are arranged in a hexagonal, rectangular, or other manner, and the number of distributions of the plurality of patterns is not limited. Figure 6h As shown, a plurality of irregular shielding patterns are arranged in the peripheral area of ​​the baffle 5, and the shapes of the plurality of patterns are different.

[0050] exist Figure 7a and Figure 7b In the embodiment shown, the central area of ​​the baffle is square in shape, and the peripheral area is partially blocked. Figure 7a As shown, a plurality of vertical stripe shielding patterns are arranged in the peripheral area of ​​the baffle, such as Figure 7b As shown, a plurality of rectangular shielding patterns are arranged in the peripheral area of ​​the baffle, the plurality of rectangular shielding patterns are arranged in rows, and the rectangular shielding patterns in different rows are arranged in a staggered manner.

[0051] Figure 8 and Fig. 9 Two special forms of baffles are given. Figure 8 In the embodiment, the central opaque area is in the shape of a drum, and a plurality of shielding patterns are arranged in the peripheral area from the inside to the outside to form an arc-shaped or annular light-transmitting pattern, wherein the width of the light-transmitting pattern increases from the center to the outside. Fig. 9 In the figure, the central area of ​​the baffle is completely opaque, and the peripheral area of ​​the baffle is also covered by the shielding material, and only a local light-transmitting area with a predetermined shape (such as the rabbit cartoon shape shown in the figure) is formed in the shielding material in the peripheral area.

[0052] The above is a schematic description of various baffle forms. It can be understood that Figures 4a to 9 The shape of the peripheral light-transmitting area shown can also be achieved by coating the surface of the second concave reflecting mirror 3, which will not be described in detail here.

[0053] Tables 1 and 2 give the surface parameters of each optical element in the two optical paths, wherein the first optical path shown in Table 1 is an optical path for normal imaging of the human eye; and the second optical path shown in Table 2 is an optical path for positive defocus imaging of the human eye.

[0054] Table 1 Surface parameters of each optical element in the first optical path

[0055]

[0056] Table 2 Surface parameters of each optical element in the second optical path

[0057] Surface marking Surface type Radius(mm) Thickness(mm) Alpha Tilt (°) Image plane Spherical unlimited 500 0 Aperture 10 Spherical unlimited 260 0 1 Spherical unlimited 200 -45 3 Spherical 730 580 -45 4 Spherical unlimited 0 0

[0058] The above-mentioned defocus protection desktop farsighted reading and writing device has an exit pupil distance between 150mm and 300mm, an exit pupil aperture of not less than φ60mm, and a field of view angle of not less than 35° and not more than 42°.

[0059] Combine the following Fig.10 and Fig.11The structure of the defocus protection desktop telescopic reading and writing device is introduced. The defocus protection desktop telescopic reading and writing device includes a bracket 11, a shell and an internal optical system. The shell includes a rear cover 12, a top cover 13, a left side plate 14 and a right side plate 15, and the rear cover 12, the top cover 13, the left side plate 14 and the right side plate 15 are connected to form a shell with a front opening and a bottom opening. The housing (specifically, the rear cover 12) is fixed to the top end of the bracket 11; the first concave reflector 2 is fixed on the rear cover 12, and the second concave reflector 3 is fixed on the top cover 13; the plane beam splitter 1 is tilted between the left side plate 14 and the right side plate 15, the top end of the plane beam splitter 1 is connected to the position between the rear cover 12 and the top cover 13, the lower end of the plane beam splitter 1 extends to the position between the lower opening and the front opening, and the left and right sides of the plane beam splitter 1 are respectively fixed to the left side plate 14 and the right side plate 15; the left side plate 14, the right side plate 15, the plane beam splitter 1 and the lower end of the vertically arranged first concave reflector 2 constitute a light inlet for the light reflected by the desktop and the objects placed on the desktop to enter; the top cover 13, the left side plate 14 and the right side plate 15 form a light shield. Due to the presence of the sunshade, the light below the light inlet is weaker. In order to ensure the intensity of the light entering the light inlet after being reflected by the desktop and the objects placed on the desktop, a fill light is provided at the bottom of at least one of the left panel 14, the right panel 15, the plane beam splitter 1 and the vertically arranged concave reflector.

[0060] Specifically, the first concave reflector 2 is fixed to the back cover 12 through a plurality of mounting blocks 21, the second concave reflector 3 is fixed to the top cover 13, an inclined mounting groove 22 is arranged on the inner walls of the left side plate 14 and the right side plate 15, and the left and right sides of the plane beam splitter 1 are installed in the above-mentioned mounting groove 22; the lower end of the plane beam splitter 1 is fixed to a horizontally arranged fixing frame 23, and the two ends of the fixing frame 23 are respectively fixed to the left side plate 14 and the right side plate 15; a baffle 24 and a handle 25 are arranged on the outer walls of the left side plate 14 and the right side plate 15, and two fill lights 26 are respectively fixed to the left side plate 14 and the right side plate 15 through mounting blocks 28; in this way, the assembly of the entire device is completed.

[0061] In summary, the defocus protection desktop telescopic reading and writing device provided by the utility model uses a bir dbath coaxial optical system to magnify and project distant images of objects such as books placed on the desktop, achieving an imaging effect similar to that of a telescope. This structure can obtain an almost distortion-free, high-definition picture without introducing a free-form surface, while reducing the difficulty of processing and adjustment. In addition, the defocus protection desktop telescopic reading and writing device also introduces a positive defocus optical path. When the user reads text and other content in a book, positive defocus stimulation is given at the same time, further inhibiting the growth of the eye axis, and at the same time may have a certain effect on the thickening of the choroid, thereby achieving myopia prevention and control.

[0062] The above is a detailed description of a defocus protection desktop telescopic reading and writing device provided by the utility model. For those skilled in the art, any obvious changes made to it without departing from the essence of the utility model will constitute an infringement of the patent right of the utility model and will bear corresponding legal responsibilities.

Claims

1. A defocus protection desktop telescopic reading and writing device, characterized in that: include: A plane beam splitter, a first concave reflecting mirror and a second concave reflecting mirror; wherein, The light reflected by the table and the object placed on the table is directed to the plane beam splitter from below and is split at the position of the plane beam splitter; The first light formed after being reflected by the plane beam splitter is reflected by the first concave reflector, and then passes through the plane beam splitter to the exit pupil position; The second light formed after passing through the plane beam splitter is reflected by the second concave reflector, and after being reflected again by the plane beam splitter, it is emitted to the exit pupil position; One of the first light ray and the second light ray directed toward the exit pupil position forms an image at a virtual image position not less than 3 meters in front of the exit pupil position, and the other forms a real image behind the exit pupil position, forming a positive defocus optical path. The diopter corresponding to the positive defocus optical path is controlled between +1D and +5D.

2. The defocus protection desktop telescopic reading and writing device according to claim 1, characterized in that: The first concave reflecting mirror and the second concave reflecting mirror have different curvature radii, wherein the concave reflecting mirror with a smaller curvature radius is used for positive defocus imaging.

3. The defocus protection desktop telescopic reading and writing device according to claim 1 or 2, characterized in that: The surface of the concave reflector used for normal imaging is coated with a total reflection film; The peripheral area of ​​the concave reflector used for positive defocus imaging is attached with a total reflection film, thereby forming a peripheral defocus light path.

4. The defocus protection desktop telescopic reading and writing device according to claim 3, characterized in that: The surface of the concave reflector used for positive defocus imaging has a light absorbing material attached to the area where the total reflection film is not provided.

5. The defocus protection desktop telescopic reading and writing device according to claim 3, characterized in that: The central area of ​​the concave reflector for positive defocused imaging is also provided with a total reflection film, and a replaceable baffle is arranged between the concave reflector for positive defocused imaging and the plane beam splitter, the baffle having a predetermined pattern to completely block light in the central area and allow light to pass through the peripheral area to achieve specific display content of the defocused light path.

6. The defocus protection desktop telescopic reading and writing device according to claim 5, characterized in that: The central area of ​​the baffle has a pattern of regular or irregular shapes, or is composed of a plurality of regular or irregular shapes spliced ​​into a complete pattern to achieve light shielding.

7. The defocus protection desktop telescopic reading and writing device according to claim 5, characterized in that: The peripheral area of ​​the baffle is completely or partially light-transmissive.

8. The defocus protection desktop telescopic reading and writing device according to claim 7, characterized in that: A plurality of shielding patterns are discretely or periodically arranged in the peripheral area of ​​the baffle to achieve local light transmission, and the plurality of shielding patterns have the same or different shapes.

9. The defocus protection desktop telescopic reading and writing device according to claim 7, characterized in that: The contour of the partial light-transmitting area of ​​the peripheral area of ​​the baffle forms a predetermined shape.

10. The defocus protection desktop telescopic reading and writing device according to claim 5, characterized in that: The baffle is a light-transmitting plate with a flat or curved surface and no light focality, and the predetermined pattern is attached to the surface of the baffle.

11. The defocus protection desktop telescopic reading and writing device according to claim 3, characterized in that: An electro-transmittance variable material is arranged between the plane beam splitter and the concave reflector for positive defocus imaging to realize the switching or conversion of the defocus mode.

12. The defocus protection desktop telescopic reading and writing device according to claim 2, characterized in that: The second concave reflector has a smaller radius of curvature and is used to reflect the second light transmitted through the plane beam splitter.

13. The defocus protection desktop telescopic reading and writing device according to claim 1 or 2, characterized in that: The surfaces of the first concave reflecting mirror and the second concave reflecting mirror are provided with total reflection films.

14. The defocus protection desktop telescopic reading and writing device according to claim 1 or 2, characterized in that: The curvature radius of the first concave reflecting mirror and the second concave reflecting mirror ranges from 400 mm to 600 mm.

15. The defocus protection desktop telescopic reading and writing device according to claim 1, characterized in that: It also includes a shell, which includes at least a left side plate and a right side plate. The left side plate, the right side plate, the plane beam splitter and the lower end of the vertically arranged concave reflector constitute a light inlet for the light reflected by the desktop and the object placed on the desktop to enter.

16. The defocus protection desktop telescopic reading and writing device according to claim 15, characterized in that: The housing further comprises a top cover, and the left side plate, the right side plate and the top cover form a light shield.

17. The defocus protection desktop telescopic reading and writing device according to claim 15 or 16, characterized in that: A fill light is arranged at the lower part of at least one of the left side plate, the right side plate, the plane beam splitter and the vertically arranged concave reflector.

Images