Projection lens system, projection apparatus, sensing module and electronic device
A projection lens system having a magnification side and a reduction side, which projects light from a conjugation surface on the reduction side onto a conjugation surface on the magnification side. The projection lens system includes a focus tunable component and a lens assembly, wherein the lens assembly includes a plurality of lens elements, and at least one surface of at least one of the lens elements includes at least one inflection point.
1. A projection lens system, having a magnification side and a reduction side, which projects a light from a conjugation surface on the reduction side onto a conjugation surface on the magnification side, the projection lens system comprising:
a focus tunable component; and
a lens assembly, comprising a plurality of lens elements, and at least one surface of at least one of the lens elements comprising at least one inflection point;
wherein a focal length of the projection lens system is f, a focal length of the focus tunable component is ft, and the following condition is satisfied:
0<|Δ( f /ft)|<0.15.
2. The projection lens system of claim 1 , wherein the focus tunable component is disposed on a magnification side of the lens assembly.
3. The projection lens system of claim 1 , wherein the focal length of the projection lens system is f, the focal length of the focus tunable component is ft, and the following condition is satisfied:
0<|Δ( f /ft)|<0.05.
4. The projection lens system of claim 1 , wherein a focal length of the lens assembly is fa, the focal length of the focus tunable component is ft, and the following condition is satisfied:
| fa /ft|<0.10.
5. The projection lens system of claim 1 , wherein a focal length of the focus tunable component at a temperature of 50° C. is ft50, the focal length of the projection lens system is f, and the following condition is satisfied:
|ft50/(100 ×f )|<15.0.
6. The projection lens system of claim 1 , wherein an axial distance between the focus tunable component and one of the lens elements closest to the magnification side in the lens assembly is Dtm, a central thickness of the focus tunable component is CTt, and the following condition is satisfied:
0.01< Dtm/CTt< 1.0.
7. The projection lens system of claim 1 , wherein the focal length of the projection lens system is f, a projection distance on the magnification side of the projection lens system is OBJ, and the following condition is satisfied:
0.01<10× f/OBJ< 0.25.
8. The projection lens system of claim 1 , wherein the focal length of the projection lens system is f, a curvature radius of a magnification-side surface of one of the lens elements closest to the magnification side in the lens assembly is Rm, and the following condition is satisfied:
f/Rm< 3.0.
9. The projection lens system of claim 1 , wherein a wavelength of the light incident into the projection lens system is A, and the following condition is satisfied:
750 nm<λ<1500 nm.
10. The projection lens system of claim 1 , wherein the focus tunable component is a liquid lens set or a liquid crystal lens set.
11. The projection lens system of claim 1 , wherein a maximum value of refractive indices of materials of the focus tunable component and the lens elements of the lens assembly is Nmax, and the following condition is satisfied:
N max<1.70.
12. The projection lens system of claim 1 , wherein the lens assembly comprises three lens groups, in order from the magnification side to the reduction side, having positive refractive power, negative refractive power and positive refractive power respectively, and at least three of the lens elements of the lens assembly have Abbe numbers smaller than 30.0.
13. The projection lens system of claim 1 , wherein an axial distance between a reduction-side surface of one of the lens elements closest to the reduction side in the lens assembly and the conjugation surface on the reduction side is BL, the focal length of the projection lens system is f, and the following condition is satisfied:
0.01< BL/f< 0.30.
14. The projection lens system of claim 1 , wherein an effective radius of a reduction-side surface of one of the lens elements closest to the reduction side in the lens assembly is SDr, an effective radius of a magnification-side surface of one of the lens elements closest to the magnification side in the lens assembly is SDm, and the following condition is satisfied:
0.10< SDr/SDm< 1.20.
15. The projection lens system of claim 1 , wherein a maximum value of effective radii of all surfaces of the lens elements in the lens assembly is SDmax, and the following condition is satisfied:
0.1 mm< SD max<0.98 mm.
16. The projection lens system of claim 1 , wherein a vertical distance between a position of an inflection point on a magnification-side surface of one of the lens elements closest to the reduction side in the lens assembly and an optical axis is Yp1, a vertical distance between a position of an inflection point on a reduction-side surface of the lens element closest to the reduction side in the lens assembly and the optical axis is Yp2, the focal length of the projection lens system is f, and the following condition is satisfied:
0.01< Yp 1/ f< 1.0; or
0.01< Yp 2/ f< 1.0.
17. The projection lens system of claim 1 , further comprising:
an aperture stop, wherein a diameter of the aperture stop is DS, an axial distance between a magnification-side surface of one of the lens elements closest to the magnification side in the lens assembly and the conjugation surface on the reduction side is TL, and the following condition is satisfied:
TL/DS< 4.0.
18. The projection lens system of claim 1 , wherein an f-number of the projection lens system is Fno, a half of a maximum field of view of the projection lens system is HFOV, and the following conditions are satisfied:
1.50< F no<3.0; and
|tan( HFOV )|<0.30.
19. The projection lens system of claim 1 , wherein an optical distortion of an effective radius position on the conjugation surface on the reduction side of the projection lens system is DIST, and the following condition is satisfied:
| DIST|< 1%.
20. The projection lens system of claim 1 , wherein at least half of a total number of the lens elements in the lens assembly are made of plastic materials, and both of a reduction-side surface and a magnification-side surface of each of the lens elements made of the plastic materials are aspheric.
21. The projection lens system of claim 20 , wherein a temperature coefficient of refractive index of each of the lens elements made of the plastic materials in the lens assembly is dn/dt, and the following condition is satisfied:
−150×10^−6(1/° C.)< dn/dt← 50×10^−6(1/° C.).
22. The projection lens system of claim 1 , wherein at least three of the lens elements of the lens assembly have Abbe numbers smaller than 23.0.
23. The projection lens system of claim 1 , wherein a curvature radius of a reduction-side surface of one of the lens elements closest to the reduction side in the lens assembly is Rr, a curvature radius of a magnification-side surface of one of the lens elements closest to the magnification side in the lens assembly is Rm, and the following condition is satisfied:
−1.0<( Rr+Rm )/( Rr−Rm )<1.0.
24. The projection lens system of claim 1 , wherein a total number of the lens elements in the lens assembly is N, and the following condition is satisfied:
2≤ N≤ 7.
25. The projection lens system of claim 1 , wherein a sum of central thicknesses of the lens elements in the lens assembly is ΣCTa, and the following condition is satisfied:
Σ CTa< 4.0 mm.
26. A projection apparatus, comprising:
the projection lens system of claim 1 ; and
at least one light source disposed on the reduction side of the projection lens system.
27. The projection apparatus of claim 26 , wherein the light source is a vertical-cavity surface-emitting laser, which is disposed on the conjugation surface on the reduction side of the projection lens system.
28. The projection apparatus of claim 26 , wherein a maximum effective diameter of the light source is DL, and the following condition is satisfied:
0.1 mm<DL<1.50 mm.
29. A sensing module, comprising:
a projection apparatus, comprising:
the projection lens system of claim 1 ; and
at least one light source; and
an image sensing apparatus, comprising:
an imaging lens system; and
an image sensor disposed on an image surface of the imaging lens system;
wherein the imaging lens system is for receiving an information on the conjugation surface on the magnification side of the projection lens system, and for imaging the information on the image sensor.
30. The sensing module of claim 29 , wherein the projection lens system further comprises a diffractive optical element, which is disposed on a magnification side of the lens assembly.
31. The sensing module of claim 29 , wherein the light source is a vertical-cavity surface-emitting laser, which is disposed on the conjugation surface on the reduction side of the projection lens system.
32. The sensing module of claim 29 , wherein a sum of central thicknesses of the lens elements in the lens assembly is ΣCTa, and the following condition is satisfied:
1.0 mm<Σ CTa< 3.0 mm.
33. An electronic device, comprising:
the sensing module of claim 29 .