CN101135831B - Projection device - Google Patents

Abstract

The invention discloses a projection device, which comprises a light source unit, a light guide element, a first focusing element, a second focusing element, a micro-mirror element and an imaging unit. Light The source unit provides a light beam, and the light beam passes through the light guide element. The first focusing element has a first focal length f₁The light beam passes through the first focusing element from the light guide element. The second focusing element has a second focal length f₂The light beam passing from the first focusing element through the second focusing element, wherein,

. The light beam enters the imaging unit from the second focusing element through the micromirror element.

Description

projection device

technical field

The invention relates to a projection device, in particular to a projection device with small size and good projection effect.

Background technique

In the optical engine of a general projection device, the light beam will undergo multiple reflections after passing through the light guide to provide sufficient brightness and good image performance. At the same time, the image and the size of each optical element can be effectively controlled through multiple focusing, thereby reducing the overall size of the optical engine. However, in a general optical engine, the focal length of the focusing element is not planned and designed as a whole, and the distance between the optical elements is not specially set. Therefore, in the process of designing the optical engine, various design problems such as poor projection effect, insufficient brightness, and dark bands on the edge often occur. In addition, if the design is simply considered only for the projection effect, there will be problems such as the size of the optical element being too large.

Contents of the invention

该光束从该第二聚焦元件，经过该微镜元件，进入该成像单元。The present invention provides a projection device to solve the problems of the prior art, including a light source unit, a light guide element, a first focusing element, a second focusing element, a micromirror element and an imaging unit. The light source unit provides a light beam passing through the light guide element. The first focusing element includes a first focal length f1, and the light beam passes through the first focusing element from the light guiding element. The second focusing element includes a second focal length f2 through which the light beam passes from the first focusing element, wherein,

The light beam enters the imaging unit from the second focusing element through the micromirror element.

By applying the present invention, a projection device with small size, sufficient brightness and good projection effect can be quickly and conveniently designed.

Description of drawings

Fig. 1 is the projection device of the present invention;

Figure 2 is a schematic diagram of the energy transfer behavior of the present invention; and

FIG. 3 is a schematic diagram of the image transmission behavior of the present invention.

Description of main component symbols:

1～projection device

100～light source unit

110～ellipsoid lamp

111～Volume light source

112～ellipsoid lampshade

120～color wheel

130～light guide element

200～lighting unit

210～first focusing element

220～reflector

230～Second focusing element

240～micromirror element

300～imaging unit

310～the first lens group

320～second lens group

400～beam

401～The first light arc

402～second light arc

403～The third light arc

404～Pupil position

411～exit light

412～The first exit light image

413～Second exit light image

Detailed ways

Referring to FIG. 1 , it shows a projection device 1 of the present invention, including a light source unit (light source unit) 100 , an illumination unit (illumination unit) 200 and an imaging unit (image unit) 300 . The light source unit 100 includes an ellipsoid lamp 110 , a color wheel (color wheel) 120 and a light guide element (light pipe, light pipe) 130 . The lighting unit 200 includes a first focusing element (relay lens) 210 , a mirror 220 , a second focusing element 230 and a micromirror element 240 . The imaging unit 300 includes a first lens group 310 and a second lens group 320 .

The ellipsoid lamp 110 includes an integral light source 111 and an ellipsoid lampshade 112 .

The volume light source 111 is disposed at the first focus of the ellipsoid shade 112 and provides a light beam 400 . The light beam 400 enters the lighting unit 200 from the ellipsoid lamp 110 , passes through the color wheel 120 and the light guide element 130 .

After entering the lighting unit 200 , the light beam 400 passes through the first focusing element 210 , the mirror 220 , the second focusing element 230 and a micromirror element 240 , and then enters the imaging unit 300 . After the light beam 400 enters the imaging unit 300 , it passes through the first lens group 310 and a second lens group 320 to project an image on a projection plane. Wherein, the second focusing element 230 and the imaging unit 300 do not overlap at the same horizontal position.

The present invention is characterized in that the first focusing element 210 has a first focal length f ₁ , and the second focusing element 230 has a second focal length f ₂ , wherein,

In the projection device 1, there are mainly two imaging behaviors, one is the energy transfer behavior, and the other is the image transfer behavior, and when the relationship between the first focal length _f1 and the second focal length _f2 satisfies , both imaging behaviors operate most efficiently while reducing aberration problems.

The design principle of the present invention will be described below with reference to the drawings.

Referring to Fig. 1 and Fig. 2, the energy transfer behavior in the projection device 1 is first described. Fig. 2 is an equivalent schematic diagram of the light guide element 130, the first focusing element 210, the second focusing element 230 and the micromirror element 240 in Fig. 1 , used to help illustrate the energy transfer behavior in the projection device 1. Referring to FIG. The light arc 401 is located on a first side of the first focusing element 210, and the first light arc 401 to the first focusing element 210 main plane (principle plane) is a first distance d1, and the first distance d1 is greater than twice the first focal length f ₁ . Therefore, the first light arc 401 will form a real image of the second light arc 402 at a position between one time and two times the first focal length f ₁ on a second side of the first focusing element 210 . There is a second distance d2 from the second light arc 402 to the main plane of the first focusing element 210, and the second distance d2 is between one time and two times the first focal length _f1 . There is a third distance d3 from the second light arc 402 to the main plane of the second focusing element 230, and the third distance d3 is between one time and two times the second focal length _f2 . Therefore, the second light arc 402 forms a real image of the third light arc 403 at a position beyond twice the second focal length f ₂ on the third side of the second focusing element 230 . There is a fourth distance d4 from the third light arc 403 to the main plane of the second focusing element 230 , and the fourth distance d4 is greater than twice the second focal length f ₂ . Thus, the third light arc 403 falls on a pupil position 404 , that is, the aperture of the imaging unit 300 .

The actual positions of the first light arc 401 , the second light arc 402 , the third light arc 403 and the pupil position 404 are shown in FIG. 1 .

Since the third light arc 403 is imaged (focused) at the pupil position 404 instead of on the projection plane of the projection device 1 , the projection device 1 has sufficient and uniform projection brightness.

In the present invention, since the light arcs (arc) are all real images, energy can be effectively transmitted and sufficient illumination brightness can be provided for the projection device.

Referring to FIG. 3 , the image transfer behavior in the projection device 1 will be described below. The exit light 411 of the light guide element 130 is located on the first side of the first focusing element 210 and has a fifth distance d5 from the main plane of the first focusing element 210 , and the fifth distance d5 is smaller than the first focal length f ₁ . Therefore, the exit light 411 will generate an upright virtual image (the first exit light image 412 ) on the first side of the first focusing element 210 . There is a sixth distance d6 from the first exit light image 412 to the main plane of the second focusing element 230 , and the sixth distance d6 is greater than twice the second focal length f ₂ . Therefore, the first exit light image 412 forms a second exit light image 413 on the micromirror element 240 between one time and twice the second focal length f ₂ on the third side of the second focusing element 230 . There is a seventh distance d7 from the second exit light image 413 to the main plane of the second focusing element 230, and the seventh distance d7 is between one time and two times the second focal length _f2 .

Since the second exit light image 413 is located between one time and two times the second focal length _f2 , the size of the second exit light image 413 can be effectively controlled. Thus, the second exit light image 413 can be fully and evenly projected on the micromirror element 240 , avoiding the occurrence of dark bands at the edge. When the second exit light image 413 is projected on the micromirror element 240 , the micromirror element 240 reflects the second exit light image 413 and passes through the imaging unit 300 to form an image on the projection plane.

因此在投影装置1中，能量传递行为以及影像传递行为会符合以上描述。针对本发明所提供的第一焦距f₁与第二焦距f₂的关系，若

的比值过大，则投影装置1的光学元件的尺寸将会过大。若

的比值过小，则第一聚焦元件210的曲率将会过大而难以制作。In the present invention, since the relationship between the first focal length _f1 and the second focal length _f2 satisfies

Therefore, in the projection device 1 , the energy transfer behavior and the image transfer behavior will conform to the above description. For the relationship between the first focal length _f1 and the second focal length _f2 provided by the present invention, if

If the ratio of is too large, the size of the optical elements of the projection device 1 will be too large. like

If the ratio of is too small, the curvature of the first focusing element 210 will be too large and difficult to manufacture.

By applying the present invention, a projection device with small size, sufficient brightness and good projection effect can be quickly and conveniently designed.

In the above embodiment, the first focusing element 210 can be a first refracting lens (such as a convex lens) made of a spherical mirror or an aspheric mirror. The second focusing element 230 can be a concave mirror made of a spherical mirror or an aspherical mirror The second focusing element 230 can also be a second refracting lens, and is matched with a reflective element (such as a flat mirror); the light beam 400 passes through the second refracting lens from the first focusing element to the reflective element, and the light beam 400 is reflected by the reflective element to Micromirror element 240..

The range of the second focal length _f2 is between 20 mm and 50 mm.

The volume light source 111 has a diameter of about 1 to 1.3 mm.

Although the present invention has been disclosed in conjunction with the specific preferred embodiments above, it is not intended to limit the present invention. Anyone skilled in the art can still make some changes and modifications without departing from the spirit and scope of the present invention. , so the protection scope of the present invention should be defined by the appended claims as the criterion.

Claims (17)

1. A projection device, comprising: a light source unit providing a light beam; a light guide element through which the light beam passes; a first focusing element comprising a first focal length f ₁ through which the light beam passes from the light guiding element; a second focusing element, comprising a second focal length _f2 , through which the light beam passes from the first focusing element, wherein,

a micromirror element; and An imaging unit, wherein the light beam enters the imaging unit from the second focusing element through the micromirror element. 2. The projection device as claimed in claim 1, wherein the second focal length _f2 ranges from 20 mm to 50 mm. 3. The projection device according to claim 1, wherein the light source unit focuses the light beam on a first end of the light guide element and forms a first light arc, and the first light arc is located at the first focusing element There is a first distance between the first light arc and the main plane of the first focusing element, and the first distance is greater than twice the first focal length. 4. The projection device according to claim 3, wherein the first light arc forms a second light arc on a second side of the first focusing element, and the second light arc is aligned with the main There is a third distance between the planes, and the third distance is between one time and two times the second focal length. 5. The projection device according to claim 1, wherein the light beam emits an exit light from a second end of the light guide element, and a fifth end is formed between the second end and the main plane of the first focusing element. distance, the fifth distance is less than the first focal length. 6. The projection device as claimed in claim 5 , wherein the exit light forms a first exit light image on a first side of the first focusing element, and the first exit light image and the main surface of the second focusing element There is a sixth distance between the planes, and the sixth distance is greater than twice the second focal length. 7. The projection device as claimed in claim 6, wherein the micromirror element is arranged on a side away from the imaging unit of the second focusing element, and there is a gap between the micromirror element and the main plane of the second focusing element A seventh distance, the seventh distance is between one time and two times the second focal length, and the first exit light image forms a second exit light image on the micromirror element. 8. The projection device as claimed in claim 1, wherein the first focusing element is a first refracting lens. 9. The projection device as claimed in claim 8, wherein the first refracting lens is a spherical mirror. 10. The projection device as claimed in claim 8, wherein the first refracting lens is an aspheric mirror. 11. The projection device as claimed in claim 8, wherein the first refracting lens is a convex lens. 12. The projection device as claimed in claim 1, wherein the second focusing element is a concave mirror. 13. The projection device as claimed in claim 12, wherein the concave reflector is a spherical mirror. 14. The projection device as claimed in claim 12, wherein the concave mirror is an aspherical mirror. 15. The projection device as claimed in claim 1, further comprising: a reflective element corresponding to the second focusing element; Wherein, the second focusing element is a second refracting lens, the light beam passes through the second refracting lens from the first focusing element to the reflective element, and the reflective element reflects the light beam to the micromirror element. 16. The projection device as claimed in claim 1, wherein the light guiding element is a light pipe. 17. The projection device according to claim 1, wherein the light source unit comprises: an ellipsoidal shade having a first focal point; and A light source is arranged on the first focal point.

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