CN207067512U - Projector and projection lens thereof - Google Patents

Abstract

A projector comprises an image light source generating device and a projection lens, wherein the image light source generating device is used for generating image light beams, the projection lens comprises a relay optical system and a projection optical system, the relay optical system is used for receiving the image light beams, the projection optical system comprises a first lens and a second lens, and a reflecting film is arranged on the surface of the first lens. Therefore, the image beam generated by the image light source generating device penetrates through the second lens, then enters the first lens, is reflected by the reflective film, leaves the first lens, penetrates through the second lens again, then exits from the projection lens and is projected to an image plane.

Description

Projector and its projection lens

technical field

The utility model relates to an optical projection device, in particular to a projector and a projection lens for reducing the formation of ghost images.

Background technique

With the advancement of video technology and the rapid development of optoelectronic technology, projection display devices such as projectors are becoming more and more popular. In addition to being used in meetings in workplaces, they can also be applied to projections in home theaters such as home entertainment. , and the projection lens used to clearly present the image on the imaging surface is one of the core components.

In order to achieve a clear projection effect in a small space, the projection lens of the projector is gradually designed in the direction of a short-focus projection lens. Many and larger lenses are used to achieve the effect of short focus and high optical power at the same time.

Known projectors and projection lenses are not only bulky and heavy, but cannot meet the requirements of miniaturization and light weight. In order to improve the above shortcomings, researchers have developed a rear-projection projector, which uses internal The reflector reflects the image beam of the projector and projects it onto the imaging surface, so as to achieve the purpose of miniaturization and weight reduction. However, when the known rear-projection projector is projecting, multiple reflections often occur between its lens groups to produce halos, light spots, etc. Due to repeated reflections, defects such as overlapping images with unstable positions and shapes, ghost images, etc. often appear on the projection screen, which not only hinders the beauty of the projection screen, but also destroys the composition of the projection screen, causing user confusion. troubled.

Therefore, how to reduce or eliminate the occurrence of defects such as ghost images to provide high-quality projection images is one of the directions of the utility model.

Utility model content

In view of this, the purpose of the present invention is to provide a projector and its projection lens which can effectively improve the problem of ghosting.

In order to achieve the above object, the utility model provides a projector, which includes: an image light source generating device, used to generate an image beam; a projection lens, used to receive the image beam and project it to an imaging surface, the The projection lens includes a relay optical system and a projection optical system; the relay optical system is located between the image light source generating device and the projection optical system, and is used to receive the image beam; the projection optical system includes a first lens and A second lens, the first lens has a first optical surface and a second optical surface opposite to each other, the first optical surface is provided with a reflective film; the second lens is located between the first lens and the relay between the optical systems, and the second lens has a third optical surface and a fourth optical surface opposite to each other, and the fourth optical surface faces the relay optical system; wherein, when the relay optical system receives the After the image beam, the image beam enters the second lens from the fourth optical surface, leaves the second lens from the third optical surface, enters the first lens from the second optical surface, and passes through the reflection After the film is reflected, it leaves the first lens from the second optical surface, enters the second lens from the third optical surface, leaves the second lens from the fourth optical surface, and projects to the imaging surface.

Wherein, the chief ray angle of the projection lens is not greater than 40 degrees.

Wherein, the diameter of the largest diameter lens in the relay optical system is not greater than the diameter of the second lens.

Wherein, the diameter of the largest-diameter lens in the relay optical system is D3, and the diameter of the second lens is D2, which satisfy the following condition: 0.3≤D3/D2≤1.0.

Wherein, the relay optical system has a third lens closest to the second lens, the diameter of the third lens is D3, and the diameter of the second lens is D2, which satisfy the following conditions: 0.3≤D3/D2≤1.0 .

Wherein, the first lens and the second lens are meniscus lenses, the second optical surface of the first lens is a concave surface, the third optical surface of the second lens is a concave surface, and the second optical surface and the second optical surface are concave. The third optical surfaces face each other.

Wherein, the second optical surface of the first lens has at least one inflection point.

In order to achieve the above purpose, the utility model also provides a projection lens for receiving an image beam and projecting it to an imaging surface, which includes: a relay optical system for receiving the image beam; a projection optical system , including a first lens and a second lens, the first lens has a first optical surface and a second optical surface opposite to each other, a reflective film is provided on the first optical surface; the second lens is located on the Between the first lens and the relay optical system, and the second lens has a third optical surface and a fourth optical surface opposite to each other, and the fourth optical surface faces the relay optical system; wherein, when After the relay optical system receives the image light beam, the image light beam enters the second lens from the fourth optical surface, leaves the second lens from the third optical surface, and enters the second lens from the second optical surface. A lens, after being reflected by the reflective film, leaving the first lens from the second optical surface, entering the second lens from the third optical surface, and leaving the second lens from the fourth optical surface, projected onto the image plane.

Wherein, the chief ray angle of the projection lens is not greater than 40 degrees.

Wherein, the diameter of the largest diameter lens in the relay optical system is not greater than the diameter of the second lens.

Wherein, the diameter of the largest-diameter lens in the relay optical system is D3, and the diameter of the second lens is D2, which satisfy the following condition: 0.3≤D3/D2≤1.0.

Wherein, the relay optical system has a third lens closest to the second lens, the diameter of the third lens is D3, and the diameter of the second lens is D2, which satisfy the following conditions: 0.3≤D3/D2≤1.0 .

Wherein, the first lens and the second lens are meniscus lenses, the second optical surface of the first lens is a concave surface, the third optical surface of the second lens is a concave surface, and the second optical surface and the second optical surface are concave. The third optical surfaces face each other.

Wherein, the second optical surface of the first lens has at least one inflection point.

The effect of the present invention is that, after the image light beam penetrates the second lens, it enters from the second optical surface of the first lens, and is reflected by the reflective film to be emitted from the second optical surface of the first lens again, and again After passing through the second lens, it is projected onto the imaging surface. Therefore, the image beam can be repeatedly passed through the projection optical system to achieve the optical design of the secondary optical effect, thereby effectively reducing the volume of the projector and the projection lens, and having high optical performance. In addition, the image light beam does not pass through the first optical surface of the first lens, but is reflected by the reflective film on the first optical surface, leaves from the second optical surface of the first lens and passes through the first optical surface again. The second lens, through the above-mentioned design, can reduce the chance of unnecessary multiple reflections of the image beam between the lenses, thereby reducing the generation of ghost images and improving the quality of projected images.

Description of drawings

FIG. 1 is a structural diagram of a projector according to an embodiment of the present invention.

FIG. 2 is a structural diagram of the projection lens of the above-mentioned embodiment.

FIG. 3 is a partially enlarged view of FIG. 2 , revealing the position of the virtual aperture.

FIG. 4 is a partially enlarged view of FIG. 2 , revealing the chief ray angle of the projection lens.

[Description of Reference Signs]

100-projector; 10-image light source generating device;

20-projection lens; 22-relay optical system;

24-projection optical system; 26-reflection film;

A-aperture; VA-virtual aperture;

D-chief ray angle; F-prism;

L1-first lens; L2-second lens;

L3-the third lens; L4～L12 lens;

S1-first optical surface; S2 second optical surface;

S3-the third optical surface; S4-the fourth optical surface;

P-image beam.

Detailed ways

In order to make the purpose, technical solutions and advantages of the utility model clearer, the utility model will be further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

In order to illustrate the utility model more clearly, an embodiment is given here and detailed description is as follows in conjunction with the accompanying drawings. As shown in FIGS. 1 and 2 , a projector 100 according to an embodiment of the present invention includes an image light source generating device 10 and a projection lens 20 .

The image light source generating device 10 is used to read image information from an image source, and has a prism F, and generates a corresponding image light beam P passing through the prism F according to the read image information. The projection lens 20 is used to receive the image beam P and project it to an imaging surface after undergoing optical processing with a predetermined effect. surface) to form a projection screen. In addition, in other practical implementations, depending on the application of different optical systems, the prism F is not limited. For example, in one embodiment, the image light source generating device 10 may not be provided with a prism, but An image light beam P is generated according to the read image information and then directly directed to the projection lens, without being limited to the above description.

The projection lens 20 includes a relay optical system 22 and a projection optical system 24 sequentially arranged from a side close to the image light source generating device 10 to a side far away from the image light source generating device 10 .

The relay optical system 22 is mainly composed of a plurality of lenses. For example, in this embodiment, the relay optical system 22 includes 10 lenses, including the third lens L3 and other lenses L4-L12, wherein the third lens L3 and lenses L5-L6, L8, L11-L12 are single-layer lenses, and lenses L4, L7, L9, and L10 are compound lenses. The compound lens can be formed by cementing two or more lenses, but not with This is the limit, and an aperture A is provided between the lens L7 and the lens L8. The relay optical system 22 is used to receive the image beam P, and transmit the image beam P according to the designed optical effect, for example, it can be designed to correct or compensate itself or the chromatic aberration introduced or such as spherical aberration, coma, Astigmatism, curvature of field, distortion and other aberrations, or light path adjustment, such as optical design for focusing, zooming, etc., but not limited thereto. In addition, in other applications, the number of lenses and the shape of the lenses of the relay optical system 22 may also be adjusted or changed according to different optical designs or characteristics.

The projection optical system 24 mainly includes a first lens L1 and a second lens L2. The first lens L1 has a first optical surface S1 and a second optical surface S2, and a reflective film 26 is disposed on the first optical surface S1. For example, in one embodiment, the first optical surface S1 can be Metal films such as silver or aluminum are plated on the top to form the reflective film 26, but not limited thereto. In other applications, reflective films of other materials can also be used. For example, dielectric films can also be used to form the reflective film 26. The reflective film is formed by, for example, using ceramic dielectric coating (Ceramic Dielectric Coating), not limited to the above-mentioned metal film. The second lens L2 is located between the first lens L1 and the relay optical system 22, and the second lens L2 has a third optical surface S3 and a fourth optical surface S4 opposite to each other. The surface S4 faces the relay optical system 22 .

In this embodiment, both the first lens L1 and the second lens L2 are meniscus lenses, the first optical surface S1 of the first lens L1 is a convex surface, the second optical surface S2 is a concave surface, and the first optical surface S2 is a concave surface. The third optical surface S3 of the second lens L2 is concave, the fourth optical surface S4 is convex, and the third optical surface S3 faces the second optical surface S2. In addition, as shown in FIG. 3 , a virtual aperture VA is formed between the first lens L1 and the second lens L2 for converging the light beam. In addition, the position of the virtual aperture VA is not perpendicular to the optical axis. Limit, can also form a predetermined inclination angle with the optical axis.

In addition, the material of the first lens L1 can be selected but not limited to plastic or glass. Preferably, in this embodiment, the first lens L1 is made of glass material, so that a higher temperature optical coating preparation method can be adopted. Instead, it is possible to form a reflective film with a large number of layers and high reflective efficiency.

In addition, the diameter of the second lens L2 is greater than or equal to the diameter of the largest lens in the relay optical system 22, that is, the diameter of the largest lens in the relay optical system 22 is not greater than the diameter of the second lens L2 diameter. For example, in this embodiment, the lens with the largest diameter in the relay optical system 22 is the third lens L3, and the third lens L3 is the lens closest to the second lens L2 in the relay optical system 22. The diameter of the third lens L3 is D3, and the diameter of the second lens L2 is D2, which satisfy the following condition: 0.3≦D3/D2≦1.0. Preferably, the ratio ( D3 / D2 ) of the diameter of the third lens L3 to the diameter of the second lens L2 is about 0.8.

In addition, as shown in FIG. 4 , the chief ray angle (CRA) of the projection lens 20 is not greater than 40 degrees. Preferably, in this embodiment, the chief ray angle D of the projection lens 20 is not greater than 26 degrees. . Therefore, through the design of the projection lens of the present utility model, the chief ray angle can be effectively reduced, and the amount of light passing through the effective optical area can be increased. In addition, the smaller lens size of the projection optical system 24 can be used. The image light beam transmitted by the relay optical system 22 is connected, which is beneficial to the miniaturization and light weight design of the lens.

Therefore, as shown in FIG. 1 and FIG. 2, when the image light source generating device 10 generates an image beam P, when the image beam P enters the projection lens 20, it first passes through the relay optical system 22, and then passes through the fourth optical beam P. Surface S4 enters the second lens L2, leaves the second lens L2 from the third optical surface S3, enters the first lens L1 from the second optical surface S2, and is reflected by the reflective film 26. Leave the first lens L1 from the second optical surface S2 of the first lens L1, enter the second lens L2 through the third optical surface S3, and leave the second lens L2 through the fourth optical surface S4 , projected to an imaging surface (not shown in the figure), for example projected to a projection screen, to form a projected picture.

Therefore, through the above-mentioned design, the image light beam P repeatedly passes through the second lens L2 and the first lens L1 to achieve a secondary optical effect. Therefore, even if the size and volume of the lens are reduced, the design of high optical performance can still be effectively achieved, and It can achieve the effect of short focus and miniaturization.

In addition, the image beam P does not pass through the first optical surface S1 of the first lens L1, but is reflected by the reflective film 26 disposed on the first optical surface S1, so as to The design of making the image beam P leave the first lens L1 again through the second optical surface S2 can reduce the loss of the quality of the image beam P and reduce the chance of unnecessary and unnecessary reflection of the image beam P, thereby reducing or eliminating Such as ghosting, glare and other defects, improve image quality.

In addition, in terms of the design of the mirror surface of the first lens L1, at least one inflection point may also be provided on the second optical surface S2 to further reduce defects such as ghost images on the projection screen. Wherein, the setting position of the inflection point can also be set at the edge of the second optical surface S2 of the first lens L1 close to the first lens L1, for example, in this embodiment, at the edge of the first lens L1 From the edge of the lens, the second optical surface S2 is provided with an inflection point about 1/3 from the center of the lens, so as to adjust the optical path of the image beam, such as adjusting the angle of the image beam to the projection screen, especially for passing through The image beam in the region between the inflection point and the edge of the lens on the second optical surface S2 is adjusted to reduce the chance of defects such as ghost images on the projection screen.

It is worth mentioning that, in other applications, the above projection optical system 24 does not exclude one or more other lenses disposed between the first lens L1 and the second lens L2, and the above description is not limited thereto. But preferably, in this embodiment, the projection optical system 24 is only provided with the first lens L1 and the second lens L2. In this way, the number of lenses of the projection optical system 24 can be reduced to reduce its cost In addition, based on the reduction of the number of lenses, the chance of unnecessary light reflection between the lenses can be reduced, especially the setting of the reflector is omitted, and the possibility of light reflection between the reflector and the lens can also be avoided, thereby Can reduce the chance of ghosting and improve image quality.

It should be mentioned again that, through the design of the projection lens of this embodiment, the image light beam P is incident on the projection optical system 24 from the lower half of the second lens L2, and then is transmitted by the upper half of the second lens L2. The portion leaves the projection optical system 24 and is projected onto the imaging surface. In this way, the optical path before being reflected by the reflective film 26 and the optical path after being reflected by the reflective film 26 will not intersect each other, and optical interference can be effectively avoided, so as to improve Projection image quality.

The above description is only a preferred feasible embodiment of the present invention. In this embodiment, the optical structure of the projector 100 and the projection lens 20 adopts the design of a telecentric system (telecentric system), but in other applications, It is not limited thereto, and in an embodiment, a non-telecentric system design may also be adopted.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the utility model in detail. It should be understood that the above descriptions are only specific embodiments of the utility model and are not intended to limit the utility model. For new models, any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present utility model shall be included within the protection scope of the present utility model.

Claims (14)

1. a kind of projecting apparatus, it includes：

One image light-source generation device, for producing an image strip；

One projection lens, for receiving the image strip and being projected to an imaging surface, the projection lens includes a relay optical system System and a projection optical system；The relay optical system be located at the image light-source generation device and the projection optical system it Between, for receiving the image strip；The projection optical system includes one first lens and one second lens, first lens With phase back to one first optical surface and one second optical surface, first optical surface is provided with a reflectance coating；This is second saturating Mirror is located between first lens and the relay optical system, and second lens have mutually back to one the 3rd optical surface with And one the 4th optical surface, the 4th optical surface face the relay optical system；

Wherein, after the relay optical system receives the image strip, the image strip from the 4th optical surface inject this second Lens, and second lens are left by the 3rd optical surface, then first lens are injected by the second optical surface, and via the reflection After film reflection, first lens are left from second optical surface, then second lens are injected by the 3rd optical surface, then by this After four optical surfaces leave second lens, the imaging surface is projected to.

2. projecting apparatus as claimed in claim 1, wherein, the chief ray angle of the projection lens is not more than 40 degree.

3. projecting apparatus as claimed in claim 1, wherein, the diameter of the lens of maximum gauge is not more than in the relay optical system The diameter of second lens.

4. projecting apparatus as claimed in claim 3, wherein, a diameter of D3 of the lens of maximum gauge in the relay optical system, A diameter of D2 of second lens, it meets following condition：0.3≤D3/D2≤1.0.

5. projecting apparatus as claimed in claim 1, wherein, the relay optical system has near the one the 3rd of second lens Lens, a diameter of D3 of the 3rd lens, a diameter of D2 of second lens, it meets following condition：0.3≤D3/D2≤ 1.0。

6. projecting apparatus as claimed in claim 1, wherein, first lens and second lens are meniscus shaped lens, and this Second optical surface of one lens is concave surface, and the 3rd optical surface of second lens is concave surface, second optical surface with this Three optical surfaces are facing.

7. projecting apparatus as claimed in claim 1, wherein, second optical surface of first lens has an at least point of inflexion.

8. a kind of projection lens, for receiving an image strip and being projected to an imaging surface, it includes：

One relay optical system, for receiving the image strip；

One projection optical system, includes one first lens and one second lens, first lens have mutually back to one the One optical surface and one second optical surface, first optical surface are provided with a reflectance coating；Second lens are located at first lens And between the relay optical system, and second lens have mutually back to one the 3rd optical surface and one the 4th optical surface, 4th optical surface faces the relay optical system；

Wherein, after the relay optical system receives the image strip, the image strip from the 4th optical surface inject this second Lens, and second lens are left by the 3rd optical surface, then first lens are injected by the second optical surface, and via the reflection After film reflection, first lens are left from second optical surface, then second lens are injected by the 3rd optical surface, then by the 4th After optical surface leaves second lens, the imaging surface is projected to.

9. projection lens as claimed in claim 8, wherein, the chief ray angle of the projection lens is not more than 40 degree.

10. projection lens as claimed in claim 8, wherein, the diameter of the lens of maximum gauge is not in the relay optical system More than the diameter of second lens.

11. projection lens as claimed in claim 10, wherein, the lens of maximum gauge is a diameter of in the relay optical system D3, a diameter of D2 of second lens, it meets following condition：0.3≤D3/D2≤1.0.

12. projection lens as claimed in claim 8, wherein, the relay optical system has near the one of second lens 3rd lens, a diameter of D3 of the 3rd lens, a diameter of D2 of second lens, it meets following condition：0.3≤D3/D2 ≤1.0。

13. projection lens as claimed in claim 8, wherein, first lens and second lens are meniscus shaped lens, should Second optical surface of first lens is concave surface, and the 3rd optical surface of second lens is concave surface, and second optical surface is with being somebody's turn to do 3rd optical surface is facing.

14. projection lens as claimed in claim 8, wherein, second optical surface of first lens has an at least contrary flexure Point.