CN206638898U - An ultra-short focal projection optical device - Google Patents

Abstract

The utility model discloses an ultra-short burnt projection optical device has set gradually in throwing the direction: an illumination system, a refractive lens assembly, an aspheric reflector; the lighting system comprises a DMD chip and an equivalent prism; the refractive lens assembly includes: the first lens group can move back and forth relative to the DMD chip, and the focal power of the first lens group is positive; the second lens group can move back and forth relative to the DMD chip, and the focal power of the second lens group is positive; the third lens group can move back and forth relative to the DMD chip, and the focal power of the third lens group is negative; and the focal power of the fourth lens group is positive relative to the fourth lens group which is static relative to the DMD chip. The utility model has high resolution, realizes the projection ratio below 0.18 and does not generate virtual focus in a high temperature state; the resolution is not reduced and the distortion is not increased under different projection distances.

Description

An ultra-short focal projection optical device

【Technical field】

The utility model relates to projection technology in the photoelectric display industry, in particular to an ultra-short-focus projection optical device.

【Background technique】

In recent years, with the development of projection technology, projectors have been widely used in household, education, office and other fields. Among them, ultra-short-focus projection can project large-size images in the case of short-distance projection, and is loved by the majority of users. .

At present, there are two design methods for ultra-short-focus projection lenses on the market: 1. Refractive anti-telephoto lens structure is adopted. The lens is large in size and uses a large number of lenses. In order to correct distortion and field curvature, the resolution has to be sacrificed. Resulting in low resolution, sensitive manufacturing tolerances, and cannot be mass-produced; 2. The hybrid structure is the refractive lens assembly plus the reflective lens group. Low, field curvature and distortion increase significantly when the projection distance changes, resulting in poor resolution, and the range of projection distance is small. Although the resolution of a few lenses reaches 1080P, in order to improve the resolution, the projection ratio is sacrificed. The addition of more aspheric surfaces leads to low manufacturing yields and cannot be mass-produced; there are also a small number of lenses that use plastic aspheric surfaces in order to reduce costs. There is no ultra-short-focus lens that can overcome the above-mentioned shortcomings at the same time.

Therefore, the utility model just produces based on above deficiency.

【Content of utility model】

The technical problem to be solved by the utility model is to provide an ultra-short-focus projection optical device, which has high resolution, high brightness, no false focus at high temperature, a large range of projection distances, no reduction in resolution and no increase in distortion under different projection distances , Can be mass produced.

In order to solve the above-mentioned technical problems, the utility model adopts the following technical solutions: an ultra-short-focus projection optical device, which is characterized in that, in the projection direction, there are sequentially arranged: an illumination system, a refracting lens assembly, and an aspheric reflector; The above lighting system includes DMD chips and equivalent prisms;

The refractive lens assembly includes:

A first lens group that can move back and forth relative to the DMD chip, the refractive power of the first lens group is positive;

A second lens group that can move back and forth relative to the DMD chip, the refractive power of the second lens group is positive;

A third lens group that can move back and forth relative to the DMD chip, the refractive power of the third lens group is negative;

The fourth lens group that is stationary relative to the DMD chip has a positive refractive power.

An ultra-short-focus projection optical device as described above is characterized in that: the first lens group includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged in sequence along the projection direction , the sixth lens, the diaphragm and the seventh lens; the second lens group includes the eighth lens; the third lens group includes the ninth lens; the fourth lens group includes the tenth lens arranged in sequence along the projection direction , the eleventh lens, the twelfth lens and the thirteenth lens.

The above-mentioned ultra-short-focus projection optical device is characterized in that: the DMD chip is placed offset from the optical axis, so that the center of the DMD chip is offset from the optical axis by a distance of 0.8mm-1mm.

The ultra-short-focus projection optical device as described above is characterized in that: the optical power of the first lens group satisfies 0.03≤|φ ₂₁₀ |≤0.04; the optical power of the second lens group satisfies 0.004≤ |φ ₂₂₀ |≤0.005; the optical power of the third lens group satisfies 0.03≤|φ ₂₃₀ |≤0.035; the optical power of the fourth lens group satisfies 0.007≤|φ ₂₄₀ |≤0.008, the non The focal power of the spherical mirror satisfies 0.03≤|φ ₃₀₀ |≤0.033.

An ultra-short focal projection optical device as described above is characterized in that: the refractive power φ ₁₁ of the eleventh lens is negative, the refractive power φ ₁₀ of the tenth lens is positive, and the refractive power satisfies 0.8≤|φ ₁₁ /φ ₁₀ |≤0.9; the refractive power φ ₁₃ of the thirteenth lens is negative, the refractive power φ ₁₂ of the twelfth lens is positive, and the refractive power satisfies 0.2≤|φ ₁₃ /φ ₁₂ |≤0.3.

An ultra-short-focus projection optical device as described above is characterized in that: the sixth lens has a negative refractive power, and the refractive power φ ₆ satisfies: 0.008≤|φ ₆ |≤0.009; the sixth lens Both sides of the lens are bent towards the DMD chip; the fifth lens has a positive power, the fourth lens has a negative power, both sides of the fourth lens are bent towards an aspheric mirror, and the power satisfies 0.04≤|φ ₄ /φ ₅ |≤0.041, the refractive index satisfies 0.3≤(ND ₄ -ND ₅ )≤0.4; the refractive power of the third lens is positive, the refractive power of the second lens is negative, and the refractive power of the second lens The two sides of both are bent to the aspheric mirror, the focal power satisfies 0.014≤|φ ₂ /φ ₃ |≤0.016, and the refractive index satisfies 0.4≤(ND ₂ -ND ₃ )≤0.43.

The ultra-short-focus projection optical device as described above is characterized in that: the second lens and the third lens are bonded by optical glue, and the fourth lens and the fifth lens are bonded by optical glue .

The above-mentioned ultra-short-focus projection optical device is characterized in that: the first lens, the sixth lens, the eighth lens, the ninth lens and the aspheric mirror are glass aspheric mirrors.

An ultra-short-focus projection optical device as described above is characterized in that: the shape of the aspheric surface of the first lens, the sixth lens, the eighth lens, the ninth lens and the aspheric mirror satisfies the equation:

The parameter c in the above equation is the curvature corresponding to the radius, y is the radial coordinate and its unit is the same as the lens length unit, and k is the conic conic conic coefficient; when the k coefficient is less than -1, the surface curve of the lens is a hyperbola; When the k coefficient is equal to -1, the surface curve of the lens is a parabola; when the k coefficient is between -1 and 0, the lens surface curve is an ellipse; when the k coefficient is equal to 0, the lens surface curve is Circular, when the k coefficient is greater than 0, the surface curve of the lens is oblate; α ₁ to α ₈ represent the coefficients corresponding to each radial coordinate.

Compared with the prior art, an ultra-short-focus projection optical device of the present invention achieves the following effects:

1. The utility model has high resolution, realizes a projection ratio below 0.18, and does not lose focus under high temperature conditions.

2. The utility model realizes that the resolution does not decrease and the distortion does not increase under different projection distances.

3. The utility model greatly reduces the assembly sensitivity by rationally allocating the focal power of the device, and can be mass-produced.

【Description of drawings】

Below in conjunction with accompanying drawing, the specific embodiment of the present utility model is described in further detail, wherein:

Fig. 1 is the utility model schematic diagram;

Fig. 2 is the utility model optical path schematic diagram;

Description of drawings: 100, lighting system; 110, DMD chip; 120, equivalent prism; 200, refracting lens assembly; 210, first lens group; 220, second lens group; 230, third lens group; 240, first Four lens groups; 300, aspheric mirror; 1, the first lens; 2, the second lens; 3, the third lens; 4, the fourth lens; 5, the fifth lens; 6, the sixth lens; 7, the first lens Seventh lens; 8. Eighth lens; 9. Ninth lens; 10. Tenth lens; 11. Eleventh lens; 12. Twelfth lens; 13. Thirteenth lens; 14. Stop.

【detailed description】

Below in conjunction with accompanying drawing, the embodiment of the present utility model is described in detail.

As shown in Figures 1 and 2, an ultra-short-focus projection optical device is sequentially arranged in the projection direction: an illumination system 100, a refractive lens assembly 200, and an aspheric mirror 300; the illumination system 100 includes a DMD chip 110 , Equivalent prism 120;

The refractive lens assembly 200 includes:

The first lens group 210 that moves back and forth relative to the DMD chip 110 has a positive refractive power; the first lens group can move back and forth relative to the DMD chip to compensate for changes in back focus during lens assembly.

The second lens group 220 that can move back and forth relative to the DMD chip 110 has a positive refractive power.

The third lens group 230 that can move back and forth relative to the DMD chip 110 , the refractive power of the third lens group 230 is negative. The third lens group and the second lens group are a linkage group and move together relative to the DMD chip 110 .

Relative to the fourth lens group 240 that is stationary with respect to the DMD chip 110 , the refractive power of the fourth lens group 240 is positive.

As shown in Figures 1 and 2, in this embodiment, the first lens group 210 includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, The fifth lens 5, the sixth lens 6, the diaphragm 14 and the seventh lens 7; the second lens group 220 includes the eighth lens 8; both sides of the eighth lens 8 are bent to the aspheric mirror 300; The three lens groups 230 include the ninth lens 9 ; the fourth lens group 240 includes the tenth lens 10 , the eleventh lens 11 , the twelfth lens 12 and the thirteenth lens 13 arranged in sequence along the projection direction.

As shown in FIG. 1 , in this embodiment, the DMD chip 110 is placed offset from the optical axis, so that the center of the DMD chip 110 deviates from the optical axis by a distance of 0.8mm-1mm. The light emitted from the refracting lens assembly 200 passes through the aspheric mirror 300 without interference with the refracting lens assembly; the DMD chip is 0.65 inches, and its resolution is 1920*1080.

As shown in Figures 1 and 2, in this embodiment, the optical power of the first lens group 210 satisfies 0.03≤|φ ₂₁₀ |≤0.04; the optical power of the second lens group 220 satisfies 0.004≤ |φ ₂₂₀ |≤0.005; the optical power of the third lens group 230 satisfies 0.03≤|φ ₂₃₀ |≤0.035; the optical power of the fourth lens group 240 satisfies 0.007≤|φ ₂₄₀ |≤0.008, so The optical power of the aspheric mirror 300 satisfies 0.03≤|φ ₃₀₀ |≤0.033. When the lens group is allocated according to the above-mentioned focal power, the projection ratio below 0.18 can be realized, the high temperature does not cause virtual focus, and the sensitivity of the device assembly tolerance can be greatly reduced, and mass production can be carried out.

The refractive power of the third lens group is negative, and the refractive power of the second lens group is positive. The third lens group and the second lens group move synchronously. The refractive power of the third lens group and the second lens group meets: 6.5 ≤|φ ₂₃₀ /φ ₂₂₀ |≤6.8, the third lens group adopts glass aspheric surface, both sides are bent towards the DMD chip, the second lens group 220 is glass aspheric surface, both sides are facing away from the DMD chip, after the above conditions are met at the same time, It can compensate the variation of the conjugate distance under different projection distances to achieve a wider range of projection distances. At the same time, it can correct field curvature and distortion under different projection distances, so that the resolution under different projection distances remains unchanged.

As shown in Fig. 1 and Fig. 2, in the present embodiment, the refractive power φ 11 of the eleventh lens ₁₁ is negative, the refractive power φ ₁₀ of the tenth lens 10 is positive, and the refractive power satisfies 0.8≤|φ ₁₁ /φ ₁₀ |≤0.9; the refractive power φ ₁₃ of the thirteenth lens 13 is negative, the refractive power φ ₁₂ of the twelfth lens 12 is positive, and the refractive power satisfies 0.2≤ |φ ₁₃ /φ ₁₂ |≤0.3. The size of the aspheric mirror can be reduced, thereby making the optical device compact.

As shown in Figure 1 and Figure 2, in this embodiment, the refractive power of the sixth lens 6 is negative, and the refractive power φ ₆ satisfies: 0.008≤|φ ₆ |≤0.009; the sixth lens 6 Both sides of the lens are bent towards the DMD chip; the spherical aberration and coma aberration produced by the aperture can be corrected, and the height of the rear group of light rays can be increased to achieve a larger aperture and improve the brightness of the projected picture; the light of the fifth lens 5 The focal power is positive, and the focal power of the fourth lens 4 is negative, satisfying 0.04≤|φ ₄ /φ ₅ |≤0.041; the refractive index satisfying 0.3≤(ND ₄ -ND ₅ )≤0.4; the fourth lens 4 The two sides of both bend towards the aspheric mirror 300; the refractive power of the third lens 3 is positive, and the refractive power of the second lens 2 is negative, satisfying 0.014≤|φ ₂ /φ ₃ |≤0.016; The refractive index satisfies 0.4≤(ND ₂ −ND ₃ )≤0.43. The high-level aberration of the device can be greatly reduced, the resolution of the device can be improved, the sensitivity of the device to aberration can be reduced, and mass production can be realized. The first lens 1 adopts a glass aspheric surface to correct distortion and astigmatism produced by other lenses of the device, so that the device finally obtains high-quality imaging.

As shown in Figures 1 and 2, in this embodiment, the second lens 2 and the third lens 3 are bonded by optical glue, and the fourth lens 4 and the fifth lens 5 are bonded by optical glue. bonding.

As shown in FIG. 1 and FIG. 2 , in this embodiment, the first lens 1 , the sixth lens 6 , the eighth lens 9 , the ninth lens 10 and the aspheric mirror 300 are glass aspheric mirrors.

As shown in Figures 1 and 2, in this embodiment, the aspheric surface shapes of the first lens 1, the sixth lens 6, the eighth lens 8, the ninth lens 9 and the aspheric mirror 300 satisfy the equation:

The parameter c in the above equation is the curvature corresponding to the radius, y is the radial coordinate and its unit is the same as the lens length unit, and k is the conic conic conic coefficient; when the k coefficient is less than -1, the surface curve of the lens is a hyperbola; When the k coefficient is equal to -1, the surface curve of the lens is a parabola; when the k coefficient is between -1 and 0, the lens surface curve is an ellipse; when the k coefficient is equal to 0, the lens surface curve is Circular, when the k coefficient is greater than 0, the surface curve of the lens is oblate; α ₁ to α ₈ represent the coefficients corresponding to each radial coordinate.

The following example shows the actual design parameters of an ultra-short-focus lens with a throw ratio of 0.18 and a resolution of 1080P:

The coefficient of the aspheric mirror S1 is:

k: -1.484

a1:0

a2: -4.1775889e-008

a3: -1.7469322e-011

a4: 1.7400545e-015

a5: -1.3744689e-019

a6: 5.819994e-024

a7: -9.0128358e-029

The coefficient of the first surface S10 of the ninth lens 9 is:

k: -1.209079

a1:0

a2: 1.4598802e-005

a3: 7.3836402e-009

a4: -1.0722255e-010

a5: 2.2856103e-013

a6: -2.2696405e-016

a7: 5.7114412e-020

The coefficient of the second surface S11 of the ninth lens 9 is:

k: -0.7290704

a1:0

a2: 3.2176776e-005

a3: 1.5832509e-007

a4: 5.9875149e-011

a5: -8.0436318e-013

a6: 2.8736159e-015

a7: 4.7557297e-018

The coefficient of the first surface S12 of the eighth lens 8 is:

k:14.41962

a1:0

a2: 7.714615e-007

a3: -4.3287749e-009

a4: -3.2946437e-011

a5: -9.887032e-014

a6: -1.4271619e-015

a7: -6.8875224e-018

a8: -1.7003567e-020

The coefficient of the second surface S13 of the eighth lens 8 is:

k: -0.7130752

a1:0

a2: -1.4711743e-006

a3: 4.3075608e-009

a4: -4.7317027e-011

a5: -2.0277632e-013

a6: -1.4895262e-016

a7: 1.5629029e-018

a8: -7.1817264e-020

The coefficient of the first surface S17 of the sixth lens 6 is:

k:21.03896

a1:0

a2: -7.4996101e-005

a3: 9.4385801e-007

a4: -2.6751325e-008

a5: -4.8054944e-010

a6: 2.7932337e-011

a7: -3.046491e-013

The coefficient of the second surface S18 of the sixth lens 6 is:

k: 0.6876403

a1:0

a2: -4.9595905e-005

a3: 2.787858e-007

a4: 1.0856431e-008

a5: -1.5897707e-010

a6: -1.7977373e-011

a7: 4.0060191e-013

The coefficient of the first surface S25 of the first lens 1 is:

k: -1.789004

a1:0

a2: 8.263905e-006

a3: -1.7911823e-008

a4: 3.7017951e-011

a5: 4.6598193e-014

a6: 7.4790277e-017

a7: 6.4726266e-019

The coefficient of the second surface S26 of the first lens 1 is:

k: -0.5580475

a1:0

a2: -2.9634338e-005

a3: 2.3313592e-008

a4: -5.5797887e-011

a5: 1.3393404e-013

a6: 2.4826738e-016

a7: 6.2566959e-019

The projection range of the ultra-short-focus projection lens is 0.35m to 0.6m. When the ultra-short-focus projection lens is focused, move the first lens group to adjust the back focus. The adjustment range is ±0.1mm. After the back focus is adjusted, the first lens group is fixed. No movement, the second lens group and the third lens group are linked to focus, and the distance between each lens group varies as follows: the distance between the first lens group and the second lens group is 17.1mm to 19.28mm, and the first lens group The distance between the second lens group and the third lens group is 14.6mm-13.5mm, and the distance between the third lens group and the fourth lens group is 2.0mm-1.0mm.

Claims (9)

1. A kind of ultra-short-focus projection optical device, it is characterized in that, on projection direction, be provided with successively: illumination system (100), refraction lens assembly (200), aspherical reflector (300); Described illumination system (100 ) includes a DMD chip (110), an equivalent prism (120); The refractive lens assembly (200) includes: A first lens group (210) that can move back and forth relative to the DMD chip (110), the refractive power of the first lens group (210) is positive; A second lens group (220) capable of moving back and forth relative to the DMD chip (110), the refractive power of the second lens group (220) being positive; A third lens group (230) capable of moving back and forth relative to the DMD chip (110), the refractive power of the third lens group (230) being negative; Relative to the fourth lens group (240) which is stationary to the DMD chip (110), the refractive power of the fourth lens group (240) is positive. 2. A kind of ultra-short focus projection optical device according to claim 1, characterized in that: said first lens group (210) comprises a first lens (1), a second lens ( 2), the third lens (3), the fourth lens (4), the fifth lens (5), the sixth lens (6), the diaphragm (14) and the seventh lens (7); the second lens group (220) includes an eighth lens (8); the third lens group (230) includes a ninth lens (9); the fourth lens group (240) includes a tenth lens (10) arranged in sequence along the projection direction , the eleventh lens (11), the twelfth lens (12) and the thirteenth lens (13). 3. A kind of ultra-short-focus projection optical device according to claim 1, characterized in that: the DMD chip (110) is placed away from the optical axis, so that the center of the DMD chip (110) deviates from the optical axis by a distance 0.8mm-1mm. 4. An ultra-short-focus projection optical device according to claim 1, characterized in that: the optical power of the first lens group (210) satisfies 0.03≤|φ ₂₁₀ |≤0.04; the second lens group The optical power of the group ( ₂₂₀ ) satisfies 0.004≤|φ220|≤0.005; the optical power of the third lens group ( ₂₃₀ ) satisfies 0.03≤|φ230|≤0.035; the fourth lens group (240) The focal power of the aspheric mirror (300) satisfies 0.007≤|φ ₂₄₀ |≤0.008, and the focal power of the aspheric mirror (300) satisfies 0.03≤|φ ₃₀₀ |≤0.033. 5. A kind of ultra-short focal projection optical device according to claim 2, is characterized in that: the refractive power φ ₁₁ of described eleventh lens (11) is negative, and the light of described tenth lens (10) The focal power φ ₁₀ is positive, and the focal power satisfies 0.8≤|φ ₁₁ /φ ₁₀ |≤0.9; the focal power φ ₁₃ of the thirteenth lens (13) is negative, and the twelfth lens (12) The focal power φ ₁₂ is positive, and the focal power satisfies 0.2≤|φ ₁₃ /φ ₁₂ |≤0.3. 6. An ultra-short-focus projection optical device according to claim 2, characterized in that: the sixth lens (6) has a negative refractive power, and the optical power φ ₆ satisfies: 0.008≤|φ ₆ | ≤0.009; both sides of the sixth lens (6) are bent towards the DMD chip (110); the refractive power of the fifth lens (5) is positive, and the refractive power of the fourth lens (4) is negative, Both sides of the fourth lens (4) are bent towards the aspheric mirror (300), the focal power satisfies 0.04≤|φ ₄ /φ ₅ |≤0.041, and the refractive index satisfies 0.3≤(ND ₄ -ND ₅ )≤0.4; The refractive power of the third lens (3) is positive, and the refractive power of the second lens (2) is negative, and both sides of the second lens (2) are bent to the aspheric mirror (300), and The degree satisfies 0.014≤|φ ₂ /φ ₃ |≤0.016, and the refractive index satisfies 0.4≤(ND ₂ -ND ₃ )≤0.43. 7. A kind of ultra-short focal projection optical device according to claim 6, characterized in that: the second lens (2) and the third lens (3) are bonded by optical glue, and the fourth lens (4) bonding with the fifth lens (5) by optical glue. 8. A kind of ultra-short focal projection optical device according to claim 2, characterized in that: the first lens (1), the sixth lens (6), the eighth lens (8), the ninth lens (9 ) and the aspheric reflector (300) are glass aspheric lenses. 9. A kind of ultra-short-focus projection optical device according to claim 8, characterized in that: the first lens (1), the sixth lens (6), the eighth lens (9), the ninth lens (10 ) and the aspheric surface shape of the aspheric mirror (300) satisfy the equation: The parameter c in the above equation is the curvature corresponding to the radius, y is the radial coordinate and its unit is the same as the lens length unit, and k is the conic conic conic coefficient; when the k coefficient is less than -1, the surface curve of the lens is a hyperbola; When the k coefficient is equal to -1, the surface curve of the lens is a parabola; when the k coefficient is between -1 and 0, the lens surface curve is an ellipse; when the k coefficient is equal to 0, the lens surface curve is Circular, when the k coefficient is greater than 0, the surface curve of the lens is oblate; α ₁ to α ₈ represent the coefficients corresponding to each radial coordinate.