A drawing projector optical system

Abstract

The utility model discloses a kind of drawing projectors optical systems, including objective lens, reflector, front fresnel lens, LCD display screen, rear fresnel lens, light cup and LED light source installed in the shell, objective lens is below reflector, light emitted by LED light source is collected by light cup and is refracted by rear fresnel lens, and uniform projection is projected to the back of LCD display screen, the image shown on the front of LCD display screen is projected to reflector after focusing by front fresnel lens, and after the reflection of reflector and the amplification of objective lens, enlarged real image is formed on projection surface to facilitate children to copy drawing;Outlet cylinder is set in the bottom of shell, objective lens barrel is threadedly connected with outlet cylinder, focusing is carried out by adjusting the movement of objective lens barrel on optical axis L2, the purpose of focusing clearly is realized, it effectively reduces axial length, makes system structure more compact, volume can be made smaller, larger field of view can be obtained, and projection area is large.

Description

Technical Field

[0001] This utility model relates to an optical system for a painting projector. Background Technology

[0002] Currently, the optical systems of commercially available painting projectors all have optical components spaced along a single optical axis. This requires a relatively large projection distance (generally exceeding 1 meter). Because all the optical elements are arranged on a straight optical axis, the axial dimension is long, resulting in a large volume, a small field of view, and a small projection area. The specific structure can be found in patent number CN202023208682, entitled "A Projection Device Using an LCD Display." Therefore, there is a need to improve this product.

[0003] In addition, the LED light source used in the projector's optical system generally adopts an array-type lamp head structure, which is prone to stray light interference, thus affecting the image quality on the LCD screen. Summary of the Invention

[0004] The purpose of this invention is to provide an optical system for a painting projector, which solves the technical problems of existing painting projector optical systems where all optical elements are arranged on a straight optical axis, resulting in a long axial dimension, large volume, small field of view, and small projection area.

[0005] The technical solution of this utility model is implemented as follows:

[0006] An optical system for a drawing projector includes an objective lens, a reflector, a front Fresnel lens, an LCD screen, a rear Fresnel lens, a reflector cup, and an LED light source, all installed inside a housing. The reflector, front Fresnel lens, LCD screen, rear Fresnel lens, reflector cup, and LED light source are sequentially distributed along the optical axis L1 at intervals. The objective lens is located below the reflector. Light emitted from the LED light source is collected by the reflector cup and reflected to the rear Fresnel lens. The rear Fresnel lens refracts the light and projects it evenly onto the back of the LCD screen. The image displayed on the front of the LCD screen is focused by the front Fresnel lens and projected onto the reflector. After reflection by the reflector and magnification by the objective lens, a magnified real image is formed on the projection surface for children to copy and draw.

[0007] The objective lens includes objective lens one and objective lens two;

[0008] Objective lens one, objective lens two, and the projection surface are distributed at intervals along the optical axis L2, and the optical axis L2 is perpendicular to the optical axis L1;

[0009] The feature is that: objective lens one and objective lens two are installed inside an objective lens tube, an exit cylinder is provided at the bottom of the housing, the inner wall of the exit cylinder is provided with internal threads, the outer surface of the objective lens tube is provided with external threads, a limit baffle protrudes from the end of the objective lens tube, the objective lens tube is nested inside the exit cylinder, and the objective lens tube is threadedly connected to the exit cylinder, and focusing is achieved by adjusting the movement of the objective lens tube on the optical axis L2.

[0010] Preferably, the front Fresnel lens, the reflector, objective lens one, and objective lens two together constitute a projection objective lens system, which projects the image displayed on the front of the LCD screen onto the projection surface; the projection objective lens system can project an 800mm×600mm image onto the projection surface at a distance of 1000mm from the objective lens.

[0011] Preferably, the LED light source is a single LED.

[0012] Preferably, limit baffles are provided at both ends of the objective lens tube.

[0013] Preferably, objective lens one and objective lens two are structurally identical and symmetrically installed. Objective lens one and objective lens two are first installed inside the inner tube, with a spacer between objective lens one and objective lens two, and the inner tube is fitted inside the objective lens tube.

[0014] Preferably, both the front and rear Fresnel lenses are constructed with a flat surface on one side and a Fresnel surface with concentric circles of varying sizes engraved on the other side. Both the Fresnel surfaces of the front and rear Fresnel lenses face the LCD display screen.

[0015] Preferably, the materials of objective lens one and objective lens two are optical plastic materials with a refractive index in the range of 1.4n-1.6n and a dispersion coefficient in the range of 30μ-60μ.

[0016] Compared with the prior art, this utility model has the following advantages:

[0017] Effect 1: The reflector, front Fresnel lens, LCD display screen, rear Fresnel lens, reflector cup and LED light source of this utility model painting projector optical system are distributed sequentially along the optical axis L1 at intervals, and objective lens one, objective lens two and projection surface are distributed at intervals along the optical axis L2, with the optical axis L2 perpendicular to the optical axis L1; this can effectively reduce the axial length, making the system structure more compact and the volume smaller.

[0018] Effect 2: Because two optical axes L1 and L2 are set, the parameters of objective lens one and objective lens two are easy to change, gaining greater freedom, a larger field of view, and a larger projection area.

[0019] Effect 3: Objective lens one and objective lens two are installed in one objective lens tube. An exit cylinder is set at the bottom of the housing. The inner wall of the exit cylinder is provided with internal threads, and the outer surface of the objective lens tube is provided with external threads. A limit baffle protrudes from the end of the objective lens tube. The objective lens tube is nested in the exit cylinder and the objective lens tube and the exit cylinder are threaded together, resulting in higher adjustment accuracy.

[0020] Other advantages of this invention will be described in more detail in the Embodiments section. Attached Figure Description

[0021] Figure 1 This is a perspective view of the present utility model;

[0022] Figure 2 This is an exploded view of the present invention;

[0023] Figure 3 This is a cross-sectional view of the structure of this utility model;

[0024] Figure 4 This is a schematic diagram of the usage state of this utility model. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0026] Example 1:

[0027] like Figures 1 to 4 As shown, this embodiment provides an optical system for a drawing projector, including an objective lens 1, a reflector 2, a front Fresnel lens 3, an LCD display screen 4, a rear Fresnel lens 5, a reflector cup 6, and an LED light source 7, all installed inside a housing 10. The reflector 2, the front Fresnel lens 3, the LCD display screen 4, the rear Fresnel lens 5, the reflector cup 6, and the LED light source 7 are sequentially distributed along the optical axis L1 at intervals. The objective lens 1 is located below the reflector 2. The light emitted by the LED light source 7 is collected by the reflector cup 6 and reflected to the rear Fresnel lens 5. The rear Fresnel lens 5 refracts the light and projects it evenly onto the back of the LCD display screen 4. The image displayed on the front of the LCD display screen 4 is focused by the front Fresnel lens 3 and projected onto the reflector 2. After reflection by the reflector 2 and magnification by the objective lens 1, a magnified real image is formed on the projection surface for children to copy and draw. The housing 10 includes an upper shell 10a and a lower shell 10b.

[0028] The objective lens 1 includes objective lens one 11 and objective lens two 12;

[0029] Objective lens 11, objective lens 2, and projection surface are distributed at intervals along optical axis L2, and optical axis L2 is perpendicular to optical axis L1;

[0030] The feature is that: objective lens 11 and objective lens 2 12 are installed inside an objective lens tube 9, an exit cylinder 8 is provided at the bottom of the housing 10, the inner wall of the exit cylinder 8 is provided with an internal thread 81, the outer surface of the objective lens tube 9 is provided with an external thread 91, a limiting baffle 92 protrudes from the end of the objective lens tube 9, the objective lens tube 9 is nested inside the exit cylinder 8, and the objective lens tube 9 is threadedly connected to the exit cylinder 8. Focusing is achieved by adjusting the movement of the objective lens tube 9 on the optical axis L2, so as to achieve a clear focus.

[0031] The advantages of this invention are as follows: 1. In the optical system of this painting projector, the reflector 2, front Fresnel lens 3, LCD display screen 4, rear Fresnel lens 5, reflector cup 6, and LED light source 7 are sequentially distributed along the optical axis L1 at intervals. Objective lens 11, objective lens 2, and the projection surface are distributed along the optical axis L2 at intervals, with the optical axis L2 perpendicular to the optical axis L1. This effectively reduces the axial length, making the system structure more compact and allowing for a smaller size. 2. Due to the two optical axes L1 and L2, the parameters of objective lens 11 and objective lens 2 are easily modified, allowing for greater freedom of movement, a larger field of view, and a larger projection area. 3: Objective lens 11 and objective lens 2 12 are installed inside an objective lens tube 9. An exit cylinder 8 is set at the bottom of the housing 10. The inner wall of the exit cylinder 8 is provided with an internal thread 81. The outer surface of the objective lens tube 9 is provided with an external thread 91. A limit baffle 92 protrudes from the end of the objective lens tube 9. The objective lens tube 9 is nested inside the exit cylinder 8 and is threadedly connected to the exit cylinder 8, resulting in higher adjustment accuracy.

[0032] Preferably, the front Fresnel lens 3, the reflecting mirror 2, the first objective lens 11, and the second objective lens 12 together constitute a projection objective lens system, which projects the image displayed on the front of the LCD screen 4 onto the projection surface; the projection objective lens system can project an 800mm×600mm image onto the projection surface at a distance of 1000mm from the objective lens. The projection area is large.

[0033] Preferably, the LED light source 7 uses a single LED, which has a simpler structure, more uniform light projection, reduces mutual interference between light sources, and ensures the image quality of the LCD display screen 4.

[0034] Preferably, limit baffles 92 are provided at both ends of the objective lens tube 9 to limit the movement distance of the objective lens tube 9 along the optical axis L2.

[0035] Preferably, objective lens 11 and objective lens 2 12 are identical parts and are symmetrically installed. Objective lens 11 and objective lens 2 12 are first installed in the inner tube 14. A spacer 13 is provided between objective lens 11 and objective lens 2 12. The inner tube 14 is fitted inside the objective tube 9. The structure is simple and the installation is convenient.

[0036] Preferably, both the front Fresnel lens 3 and the rear Fresnel lens 5 are constructed with a flat surface on one side and a Fresnel surface with concentric circle textures of increasing size engraved on the other side. The Fresnel surfaces of the front Fresnel lens 3 and the rear Fresnel lens 5 face the LCD display screen 4, which is a reasonable layout.

[0037] Preferably, objective lens 11 and objective lens 2 12 are made of optical plastic material with a refractive index in the range of 1.4n-1.6n and a dispersion coefficient in the range of 30μ-60μ.

[0038] The above embodiments are preferred embodiments of the present utility model, but the embodiments of the present utility model are not limited thereto. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present utility model are equivalent substitutions and are included within the protection scope of the present utility model.

Claims

1. An optical system for a drawing projector, comprising an objective lens (1), a reflector (2), a front Fresnel lens (3), an LCD display screen (4), a rear Fresnel lens (5), a reflector cup (6), and an LED light source (7) installed inside a housing (10). The reflector lens (2), the front Fresnel lens (3), the LCD display screen (4), the rear Fresnel lens (5), the reflector cup (6), and the LED light source (7) are sequentially distributed along the optical axis L1 at intervals. The objective lens (1) is located below the reflector lens (2). The light emitted by the LED light source (7) is collected by the reflector cup (6) and reflected to the rear Fresnel lens (5). The rear Fresnel lens (5) refracts the light and projects it evenly onto the back of the LCD display screen (4). The image displayed on the front of the LCD display screen (4) is focused by the front Fresnel lens (3) and projected onto the reflector lens (2). After being reflected by the reflector lens (2) and magnified by the objective lens (1), a magnified real image is formed on the projection surface for children to copy and draw. The objective lens (1) includes objective lens one (11) and objective lens two (12); The objective lens one (11), objective lens two (12) and projection surface are distributed at intervals along the optical axis L2, and the optical axis L2 is perpendicular to the optical axis L1; Its features are: Objective lens 1 (11) and objective lens 2 (12) are installed inside an objective lens tube (9). An exit cylinder (8) is provided at the bottom of the housing (10). The inner wall of the exit cylinder (8) is provided with an internal thread (81). The outer surface of the objective lens tube (9) is provided with an external thread (91). A limit baffle (92) protrudes from the end of the objective lens tube (9). The objective lens tube (9) is nested inside the exit cylinder (8) and the objective lens tube (9) is threadedly connected to the exit cylinder (8). Focusing is achieved by adjusting the movement of the objective lens tube (9) on the optical axis L2.

2. The optical system for a painting projector according to claim 1, characterized in that: The front Fresnel lens (3), the reflector (2), the first objective lens (11) and the second objective lens (12) together constitute a projection objective lens system, which projects the image displayed on the front of the LCD screen (4) onto the projection surface; the projection objective lens system can project an image of 800mm×600mm on the projection surface at a distance of 1000mm from the objective lens.

3. The optical system for a painting projector according to claim 1 or 2, characterized in that: The LED light source (7) uses a single LED.

4. The optical system for a painting projector according to claim 3, characterized in that: Limiting baffles (92) are provided at both ends of the objective lens tube (9).

5. The optical system for a painting projector according to claim 3, characterized in that: Objective lens 1 (11) and objective lens 2 (12) are identical parts and are symmetrically installed. Objective lens 1 (11) and objective lens 2 (12) are first installed in the inner tube (14). A spacer (13) is provided between objective lens 1 (11) and objective lens 2 (12). The inner tube (14) is fitted inside the objective tube (9).

6. The optical system for a painting projector according to claim 5, characterized in that: Both the front Fresnel lens (3) and the rear Fresnel lens (5) are constructed with a flat surface on one side and a Fresnel surface with concentric circles engraved on the other side. The Fresnel surfaces of the front Fresnel lens (3) and the rear Fresnel lens (5) face the LCD display screen (4).

7. The optical system for a painting projector according to claim 6, characterized in that: Objective lens 1 (11) and objective lens 2 (12) are made of optical plastic material with a refractive index in the range of 1.4n-1.6n and a dispersion coefficient in the range of 30μ-60μ.

Images