Suspension type vibration system for rear projection volume display

Abstract

The invention discloses a suspension type vibration system for rear projection volume display. Comprising a vibrating table, an elastic part, a reflecting table, a pulley block, a rear projection table, a movable reflector, an imaging screen and a rack, the vibration table is fixedly installed on the rack, the reflection table is elastically connected with the vibration table through the elastic piece, the movable reflector is fixed to the reflection table, the reflection face of the movable reflector is horizontally upward, the pulley block is fixedly installed on the reflection table, a part of a steel wire rope on the pulley block is fixed to the rack, and the steel wire rope on the pulley block is fixedly connected with the rear projection table. And the imaging screen is fixedly connected to the rear projection table. The vibration table vibrates slightly along the vertical direction according to the inherent frequency of the system, the suspension system generates resonance, the reflection table vibrates greatly along the vertical direction, and the back projection table generates vibration which is two times of the amplitude of the reflection table through the moving pulley block, so that the optical path displayed by the back projection volume is kept constant, and the display precision is improved. And the equal-earth imaging is always clear on the rear projection screen.

Description

Technical Field

[0001] The present invention relates to a suspended vibration system for rear-projection volume display, and in particular to a suspended vibration system for rear-projection volume display capable of ensuring a constant optical path. Background Art

[0002] The first suspended rear projection volume display system has been disclosed, such as Figure 1 As shown. On a vibration table 1 that can generate vertical vibration, a rear projection table 5 is suspended by an elastic member 4, and an imaging screen 9 is fixed to the rear projection table 5, with the imaging surface horizontal; when the vibration table 1 is stationary, they together form a single-degree-of-freedom suspension system that vibrates in the vertical direction. The natural frequency of this single-degree-of-freedom suspension system is not less than 10Hz and can be used as the scanning frequency of the rear-projection volume display. When the vibration table 1 vibrates slightly at this natural frequency, the system resonates and the imaging table 5 vibrates sharply. The actual amplitude A after stabilization is controlled by fine-tuning the amplitude e of the vibration table. At the same time, the light emitted from the fixed projector 6 is reflected by the fixed reflector 7 and projected onto the moving imaging screen 9, forming a two-dimensional image sequence of different heights in the imaging area 10; with the help of the visual persistence effect, these two-dimensional image sequences are superimposed into a three-dimensional image for the observer.

[0003] The advantage of this system is that, through its suspension, it effectively solves the noise problem generated by the high-speed reciprocating motion of the imaging screen. However, because the optical path from projector 6 to imaging screen 9 changes rapidly, this creates two limitations: First, the shape of imaging area 10 is smaller at the bottom and larger at the top, resulting in uneven voxel size; second, the imaging depth of field, namely the height A of imaging area 10, is severely limited, as a clear image can only be obtained when imaging screen 9 is near the focal plane of projector 6.

[0004] The second type of suspended rear projection volume display system has been disclosed, such as Figure 2 As shown, a rear projection stage 5, with an imaging screen 9 (with the imaging surface horizontal), is mounted on a reflective platform 3 via a second elastic member 4. A dynamic reflector 8 is fixed to the reflective platform 3, with the reflecting surface horizontal. The reflective platform 3 is mounted on a vibration platform 1 capable of generating vertical vibration via elastic members 2. When the vibration platform 1 is stationary, the system and the system together form a two-degree-of-freedom suspension system capable of vertical vibration.

[0005] This dual-degree-of-freedom suspension system exhibits a vertical vibration natural mode with a natural frequency of no less than 10 Hz, which can be used as the scanning frequency for rear-projection volumetric displays. The rear-projection stage and the reflector stage vibrate in phase, and the rear-projection stage's amplitude, A2, is approximately twice the reflector stage's amplitude, A1; that is, A2 ≈ 2A1. When the vibration table 1 vibrates slightly at this natural frequency, the system resonates, exciting the natural mode. The actual amplitude of this mode after stabilization can be controlled by fine-tuning the amplitude, e, and frequency of the vibration table 1. Simultaneously, when light emitted from the fixed projector 6, after being reflected by the fixed mirror 7 and the moving reflector 8, reaches the moving imaging screen 9, the optical path remains essentially constant due to the vibration characteristics of the natural mode, i.e., A2 ≈ 2A1. This results in a sequence of two-dimensional images of varying heights but essentially equal size formed within the imaging area. Through the persistence of vision effect, these two-dimensional images are superimposed into a substantially clear three-dimensional image for the observer.

[0006] Compared to the first previously disclosed system, this system offers the following advantages: Regardless of the amplitude A1 of the rear projection stage or the position of the imaging screen, a clear and uniform image is always achieved. However, during implementation, it was discovered that due to the presence of spring mass and various damping factors, as well as the nonlinear effects of the suspension system itself, the actual ratio of A1 to A2 during stable operation depends on factors such as amplitude and frequency. Therefore, the requirement for a constant optical path, A2 ≈ 2A1, is difficult to achieve. Summary of the Invention

[0007] In order to further solve the problems existing in the second disclosed system in the background art, the purpose of the present invention is to provide a suspended vibration system for rear-projection volume display that ensures a constant optical path.

[0008] The technical solution adopted by the present invention to solve its technical problem is:

[0009] The present invention includes a vibration table, an elastic member, a reflection table, a pulley block, a rear projection table, a dynamic reflector, an imaging screen and a frame; the vibration table is fixedly installed on the frame, the reflection table is elastically connected to the vibration table via the elastic member, the dynamic reflector is fixed on the reflection table with the reflection surface facing upward horizontally, the pulley block is fixedly installed on the reflection table, a part of the steel wire rope on the pulley block is fixed on the frame, the steel wire rope on the pulley block is fixedly connected to the rear projection table, and the imaging screen is fixedly connected to the rear projection table.

[0010] The pulley group includes two pulleys that are arranged at an interval up and down and fixed in position to each other. The two pulleys are connected by a closed-loop steel wire rope, wherein the lower pulley is fixedly mounted on the reflection platform, one side of the steel wire rope between the two pulleys of the pulley group is fixed on the frame, and the other side of the steel wire rope between the two pulleys of the pulley group is fixedly connected to the lower end of the rear projection platform.

[0011] It includes multiple groups of pulley groups, each group of pulley groups is symmetrically arranged on both sides between the reflection platform and the rear projection platform, an anchor point is set on the outside of the steel wire rope of each pulley group and fixed to the frame, and an anchor point is set on the inside of the steel wire rope of each pulley group and fixedly connected to the lower end of the rear projection platform through an intermediate tie.

[0012] The light beam emitted by the external projector is incident on the moving reflector and is reflected by the moving reflector onto the imaging screen.

[0013] A plurality of elastic members are provided between the reflection platform and the vibration platform.

[0014] The elastic member is arranged horizontally or vertically.

[0015] By adjusting the elasticity of the elastic member, the mass of the reflection platform, the mass of the pulley block and the mass of the rear projection platform, the natural frequency of the vertical vibration of the suspended vibration system is made not less than 10 Hz.

[0016] The vibration table vibrates slightly in the vertical direction. By adjusting the frequency and amplitude of the vibration, the suspended vibration system resonates. Driven by the elastic parts and the pulley group, the rear projection table and the reflection table produce stable, in-phase and larger vibrations in the vertical direction, and the amplitude of the rear projection table is always twice that of the reflection table.

[0017] The elastic member is an elastic device such as a tension spring or a rubber band, or other elastic devices with suitable elasticity, or is composed of multiple identical elastic devices connected in parallel.

[0018] The pulley block is a pulley block, and the steel wire rope is a steel belt or a belt made of other materials.

[0019] In the present invention, when the vibration table is stationary, they together form a single-degree-of-freedom suspension system that vibrates vertically. This single-degree-of-freedom suspension system has a natural frequency of no less than 10 Hz, which can be used as the scanning frequency for rear-projection volumetric displays. Due to the kinematic characteristics of the pulley assembly, as long as the reflector table moves vertically, the rear-projection table will move in the same direction, and the amplitude of the motion will be twice that of the reflector table 3, ensuring that A2 = 2A1.

[0020] When the vibration table vibrates slightly at the natural frequency, the system resonates. The actual amplitude after stabilization can be controlled by fine-tuning the vibration table's amplitude e and frequency. Due to the kinematic characteristics of the pulley system, A2 always equals 2A1, regardless of frequency and amplitude variations. Therefore, when used for volumetric display, the optical path is kept constant, resulting in a clear, uniform image on the rear projection screen.

[0021] The beneficial effects of the present invention are:

[0022] Compared with the two previously disclosed suspended rear-projection volume display systems, the present invention introduces a pulley set to force the vibration amplitude of the rear-projection table to be twice that of the reflection table and in the same direction. It is no longer related to other factors such as spring mass, damping, system nonlinearity, amplitude, frequency, etc., thereby always satisfying the constant optical path, that is, A2=2A1.

[0023] The present invention is particularly suitable for high-definition and high-depth-of-field volume display, and has broad application prospects in fields involving three-dimensional objects, such as industrial design, scientific research, teaching demonstration, medical CT analysis, and spatial mechanism motion simulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is the first schematic diagram of the disclosed invention;

[0025] Figure 2 It is a schematic diagram of the second disclosed invention;

[0026] Figure 3 It is a schematic diagram of the present invention;

[0027] Figure 4 It is a schematic diagram of an embodiment of the present invention; Figure 5 is a schematic diagram of a second embodiment of the present invention;

[0028] In the figure: 1. vibration table, 2. elastic member, 3. reflection table, 4. second elastic member, 5. rear projection table, 6. projector, 7. fixed optical mirror, 8. dynamic reflector, 9. imaging screen, 10. imaging area, 11. pulley block, 12. inner wire rope, 13. outer wire rope, 14. frame. DETAILED DESCRIPTION

[0029] The present invention will be further described below with reference to the accompanying drawings and specific implementations.

[0030] like Figure 3 As shown, the system includes a vibration table 1, an elastic member 2, a reflecting table 3, a pulley block 11, a rear projection table 5, a dynamic reflector 8, an imaging screen 9 and a frame 14; the vibration table 1, the reflecting table 3 and the rear projection table 5 are arranged in sequence from bottom to top in the vertical direction, the vibration table 1 is fixedly mounted on the frame 14, the reflecting table 3 is elastically connected to the vibration table 1 through the elastic member 2, the dynamic reflector 8 is fixed to the reflecting table 3 with the reflecting surface horizontally facing upward, the pulley block 11 is fixedly mounted on the reflecting table 3, a small section of the steel wire rope 12 on one side of the pulley block 11 is fixed to the frame 14, a small section of the steel wire rope 13 on the other side of the pulley block 11 is fixedly connected to the rear projection table 5, and the imaging screen 9 is fixedly connected to the rear projection table 5 with the imaging surface horizontally facing upward.

[0031] Each pulley block 11 is composed of a pair of pulleys, each pair of pulleys is arranged up and down, and is closed and connected by a steel wire rope.

[0032] More specifically, each pulley assembly 11 comprises two pulleys spaced apart and fixed relative to each other. The two pulleys are connected by a closed-loop steel cable. The lower pulley is fixedly mounted on the reflector 3, and the two pulleys are fixed relative to each other by a bracket. A small section of the cable between the two pulleys in the pulley assembly 11 is fixed to the frame 14 on one side 12, while a small section of the cable on the other side 13 is fixed to the lower end of the rear projection stage 5.

[0033] In the specific implementation, two or more pulley groups 11 are set up and symmetrically arranged between the reflection platform 3 and the rear projection platform 5. An anchor point is set on one side 12 of the steel wire rope of each pulley group 11 and fixed to the frame 14. An anchor point is set on the other side of the steel wire rope of each pulley group 11 and fixed to the lower end of the rear projection platform 5.

[0034] The light beam emitted by the external projector 6 is incident on the moving reflector 8 and is reflected by the moving reflector 8 onto the imaging screen 9 .

[0035] There may be multiple elastic members 2 between the reflection platform 3 and the vibration platform 1 . The elastic members 2 may also be connected between the four corners of the reflection platform 3 and the four corners of the vibration platform 1 .

[0036] The elastic member 2 is arranged horizontally or vertically. For example, one end of the elastic member 2 is hung on the vibration table 1, and after being pulled obliquely in a substantially horizontal direction, the other end is hung on the reflection table 3.

[0037] When the vibration table 1 is stationary, it forms a single-degree-of-freedom suspension system that vibrates vertically. By adjusting the elasticity of the spring element 2, the mass of the reflection table 3, the mass of the pulley assembly 11, and the mass of the rear projection stage 5, the suspended vibration system's natural frequency in the vertical direction is maintained at no less than 10 Hz.

[0038] The natural frequency of this single-degree-of-freedom suspension system is no less than 10 Hz, which can be used as the scanning frequency for rear-projection volumetric displays. Due to the kinematic characteristics of the pulley assembly, as long as reflector 3 moves vertically, rear-projection stage 5 will move in the same direction, and the amplitude of the motion will be twice that of reflector 3, so A2 always equals 2A1.

[0039] When the vibration table 1 vibrates slightly at the natural frequency, the system resonates. The actual amplitude after stabilization can be controlled by fine-tuning the vibration table's amplitude e. Due to the kinematic characteristics of the pulley system, A2 always holds equal to 2A1, regardless of changes in frequency and amplitude. Therefore, when used for volumetric display, the optical path is kept constant, resulting in a sequence of two-dimensional images of varying heights but equal size within the imaging area.

[0040] The first embodiment of the present invention is Figure 4 shown.

[0041] Starting from the four corners of a vibration table 1 that vibrates slightly in the vertical direction, an elastic member 2 composed of eight tension springs pulls the eight corners of a reflecting platform 3 diagonally in a nearly horizontal direction. The reflecting platform 3 is a rectangular frame formed by eight optical axes fixedly connected. A dynamic reflector 8 is installed at the bottom of the reflecting platform 3, with the reflecting surface facing horizontally upward. Four pulley groups 11 are installed on the reflecting platform 3. A steel wire rope 12 on one side of each pulley group is fixedly connected to the frame 14 via an anchor point. A steel wire rope 13 on the other side of each pulley group is fixedly connected to the lower end of the rear projection platform 5 via an anchor point. The rear projection platform 5 is a box-shaped structure with an open bottom, and its upper surface is fixedly connected to the imaging screen 9 to form a horizontal imaging surface.

[0042] The second embodiment of the present invention is Figure 5 shown.

[0043] The reflecting table 3 is a rectangular frame formed by eight optical axes fixedly connected together; the elastic member 2 is composed of eight tension springs, divided into two groups of four; one group starts from the four corners above the vibration table 1 and pulls the four corners below the reflecting table 3 upward in the vertical direction; the other group starts from the four corners below the vibration table 1 and pulls the four corners above the reflecting table 3 downward in the vertical direction; the dynamic reflector 8 is installed at the bottom of the reflecting table 3, with the reflecting surface facing horizontally upward; four pulley groups 11 are installed on the reflecting table 3; a steel wire rope 12 on one side of each pulley group is fixedly connected to the frame 14 through an anchor point; a steel wire rope 13 on the other side of each pulley group is fixedly connected to the lower end of the rear projection table 5 through an anchor point. The rear projection table 5 is a box-shaped structure with an open bottom, and its upper surface is fixedly connected to the imaging screen 9 to form a horizontal imaging surface.

[0044] The above specific embodiments are used to illustrate the present invention rather than to limit the present invention. Any modifications and changes made to the present invention within the spirit of the present invention and the protection scope of the claims shall fall within the protection scope of the present invention.

[0045] The above description is only a preferred embodiment of the present invention. Therefore, any equivalent changes or modifications made according to the structure, characteristics and principles described in the scope of the patent application of the present invention are included in the scope of the patent application of the present invention.

Claims

1. A suspended vibration system for rear-projection volumetric display, characterized in that: The invention comprises a vibration table (1), an elastic member (2), a reflection table (3), a pulley block (11), a rear projection table (5), a dynamic reflector (8), an imaging screen (9) and a frame (14); the vibration table (1) is fixedly mounted on the frame (14); the reflection table (3) is elastically connected to the vibration table (1) through the elastic member (2); the dynamic reflector (8) is fixed on the reflection table (3) with the reflection surface facing upward; the pulley block (11) is fixedly mounted on the reflection table (3); a part of the steel wire rope on the pulley block (11) is fixed on the frame (14); the steel wire rope on the pulley block (11) is fixedly connected to the rear projection table (5); and the imaging screen (9) is fixedly connected to the rear projection table (5).

2. The suspended vibration system for rear-projection volumetric display according to claim 1, characterized in that: The pulley block (11) comprises two pulleys spaced apart and fixed to each other, the two pulleys being connected by a closed-loop steel wire rope, wherein the lower pulley is fixedly mounted on the reflection platform (3), one side of the steel wire rope between the two pulleys of the pulley block (11) is fixed to the frame (14), and the other side of the steel wire rope between the two pulleys of the pulley block (11) is fixedly connected to the lower end of the rear projection platform (5).

3. The suspended vibration system for rear-projection volumetric display according to claim 1, characterized in that: The invention comprises a plurality of pulley groups (11), each pulley group (11) being symmetrically arranged on both sides between the reflection platform (3) and the rear projection platform (5), an anchor point being arranged on the outer side of the steel wire rope of each pulley group (11) and fixed on the frame (14), and an anchor point being arranged on the inner side of the steel wire rope of each pulley group (11) and fixedly connected to the lower end of the rear projection platform (5) through an intermediate tie.

4. The suspended vibration system for rear-projection volumetric display according to claim 1, characterized in that: The light beam emitted by the external projector (6) is incident on the dynamic reflector (8) and is reflected by the dynamic reflector (8) onto the imaging screen (9).

5. The suspended vibration system for rear-projection volumetric display according to claim 1, characterized in that: A plurality of elastic members (2) are provided between the reflection platform (3) and the vibration platform (1).

6. The suspended vibration system for rear-projection volumetric display according to claim 1, characterized in that: The elastic member (2) is arranged horizontally or vertically.

7. The suspended vibration system for rear projection volume display according to claim 1, characterized in that: By regulating the elasticity of the elastic member (2), the mass of the reflection platform (3), the mass of the pulley block (11) and the mass of the rear projection platform (5), the natural frequency of the vertical vibration of the suspended vibration system is made not less than 10 Hz.

8. The suspended vibration system for rear-projection volumetric display according to claim 1, characterized in that: The vibration table (1) vibrates in the vertical direction, and by adjusting the frequency and amplitude of the vibration, the suspended vibration system generates resonance. Driven by the elastic member (2) and the pulley group (11), the rear projection table (5) and the reflection table (3) generate larger vibrations in the same phase in the vertical direction, and the amplitude of the rear projection table (5) is always twice that of the reflection table (3).

9. The suspended vibration system for rear-projection volumetric display according to claim 1, characterized in that: The elastic member (2) is an elastic device such as a tension spring or a rubber band, or other elastic devices with suitable elasticity, or is composed of multiple identical elastic devices connected in parallel.

10. The suspended vibration system for rear projection volume display according to claim 1, characterized in that: The pulley block (11) is a pulley block, and the steel wire rope is a steel belt or a belt made of other materials.

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