The invention relates generally to an optical lens system, and more particularly to an optical lens system adapted to transmit short wavelength light for imaging purpose.
Generally, an optical lens system that uses short wavelength light as a light source is favorable for forming an image of fine patterns, since the size of the smallest spot image that can be resolved is in proportion to the wavelength. However, the optical lens system using short wavelength light is difficult to achieve a high light transmittance and may cause considerable chromatic aberrations that increase as the wavelength decreases. Therefore, it is desirable to provide a high-performance optical lens system that has an improved light transmittance and is favorable for correcting chromatic aberrations.
According to one aspect of the present disclosure, an optical lens system for imaging includes, in order from a magnified side to a minified side, a first lens group of positive refractive power and a second lens group of positive refractive power. The first lens group includes a first lens and a second lens, and the second lens group includes a third lens and a fourth lens. One of the third lens and the fourth lens includes one aspheric surface, and each of the lenses in the optical lens system is a singlet lens. During focusing, the first lens group remains stationary and the second lens group is movable in a direction of an optical axis. The optical lens satisfies a condition of TE(λ=400)>94%, where TE(λ=400) denotes an overall transmittance of all of the lenses in the optical lens system measured at a wavelength of 400 nm.
Other objectives, features and advantages of the invention will be further understood from the further technological features disclosed by the embodiments of the invention wherein there are shown and described preferred embodiments of this invention, simply by way of illustration of modes best suited to carry out the invention.
In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings which form a part hereof, and in which are shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology, such as “top,” “bottom,” “front,” “back,” etc., is used with reference to the orientation of the Figure(s) being described. The components of the invention can be positioned in a number of different orientations. As such, the directional terminology is used for purposes of illustration and is in no way limiting. On the other hand, the drawings are only schematic and the sizes of components may be exaggerated for clarity. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the invention. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless limited otherwise, the terms “connected,” “coupled,” and “mounted” and variations thereof herein are used broadly and encompass direct and indirect connections, couplings, and mountings. Similarly, the terms “facing,” “faces” and variations thereof herein are used broadly and encompass direct and indirect facing, and “adjacent to” and variations thereof herein are used broadly and encompass directly and indirectly “adjacent to”. Therefore, the description of “A” component facing “B” component herein may contain the situations that “A” component directly faces “B” component or one or more additional components are between “A” component and “B” component. Also, the description of “A” component “adjacent to” “B” component herein may contain the situations that “A” component is directly “adjacent to” “B” component or one or more additional components are between “A” component and “B” component. Accordingly, the drawings and descriptions will be regarded as illustrative in nature and not as restrictive.
An optical lens system according to an embodiment of the invention may include a first lens group 20 of positive refractive power and a second lens group 30 of positive refractive power. The second lens group 30 may include at least one aspherical lens surface for correcting different kinds of optical aberrations such as spherical aberration, coma, astigmatism, field curvature, and image distortion. Besides, the second lens group 30 may include at least one cemented lens to balance chromatic aberration. A spatial light modulator 16, for example, a digital micro-mirror device (DMD), selectively reflects illumination light to produce image light, and the image light may pass through a cover plate 18, a deflection prism 22, the second lens group 30, and the first lens group 20 in succession, and then the image light is projected onto an object (not shown).
In one embodiment, each of the lenses in the optical lens system may be made of glass. When the lens is made of glass, the distribution of the refractive power of the optical lens system may be more flexible to design, and the glass material is not sensitive to temperature variations to ensure competent resolution of the optical lens system under different ambient temperatures. Further, because the second lens group 30 may include at least one aspherical lens surface, more controllable variables are obtained, and the aberration is reduced, as well as the number of required lenses can be minified on constructing an optical lens system to reduce the total track length.
In one embodiment, the optical lens system may use short wavelength light such as blue light or ultraviolet as a light source. The optical lens system according to one embodiment may satisfy the following condition:
T(λ=400)>95%; and
TE(λ=400)>94%, where T(λ=400) denotes a transmittance of a lens material forming each of the lenses in the optical lens system, with the transmittance of the lens material being measured at a wavelength of 400 nm and a thickness of 10 mm, and TE(λ=400) denotes an overall transmittance of all of the lenses in the optical lens system measured at a wavelength of 400 nm.
Further, the optical lens system according to one embodiment may satisfy the following condition:
T(λ=350)>90%; and
TE(λ=350)>80%, where T(λ=350) denotes a transmittance of a lens material forming each of the lenses in the optical lens system, with the transmittance of the lens material being measured at a wavelength of 350 nm and a thickness of 10 mm, and TE(λ=350) denotes an overall transmittance of all of the lenses in the optical lens system measured at a wavelength of 350 nm.
In one embodiment, the optical lens system may satisfy the following condition:
C/N≥0.7, where N denotes a total number of the lenses in the optical lens system, and C denotes a number of the lenses having an Abbe number of larger than 40 in the optical lens system.
According to the above embodiments, the optical lens system is featured with good correction ability, high light transmittance and improved image quality.
A first design example of an optical lens system 10a is described in detail below with reference to
According to the optical lens system of the present disclosure, each of a magnified-side and a minified-side surface of a lens has a paraxial region and a peripheral region. The paraxial region refers to the region of the surface where light rays travel close to an optical axis and the peripheral region refers to the region of the surface where light rays travel away from the optical axis. Particularly, when a lens has a convex surface, it may indicate that the surface is convex at the paraxial region; and when the lens has a concave surface, it may indicate that the surface is concave at the paraxial region.
The detailed optical data of the first example are shown in Table 1 below.
Further, the aspheric surface satisfies the following equation:
where x denotes a displacement from the vertex of a lens in the direction of the optical axis 12, c′ denotes a reciprocal of the radius of curvature at the vertex of a lens (approaching the optical axis 12), K denotes a Conic constant, y denotes a height (distance in the direction perpendicular to the optical axis 12) of the aspheric surface, and A, B, C, D, E, F and G are aspheric coefficients. The values of aspheric coefficients and Conic constant of each lens surface are listed in Table 2.
Table 3 lists the internal transmittance of each of the lenses L1-L9 of the optical lens system 10a and the overall transmittance of all of the lenses L1-L9 at different wavelengths. As used herein, the term “internal transmittance” of a lens means a transmittance of a lens material forming such lens, and the transmittance of the lens material is measured at a thickness of 10 mm and a selected wavelength specified in the table. Table 3 clearly shows each of the lenses L1-L9 may have a light transmittance of larger than 95% at a wavelength of 380 nm or 400 nm.
A second design example of an optical lens system 10b including nine lenses L1-L9 is described in detail below with reference to
Table 6 lists the internal transmittance of each of the lenses L1-L9 of the optical lens system 10b and the overall transmittance of all of the lenses L1-L9 at different wavelengths. Table 6 clearly shows each of the lenses L1-L9 may have an internal transmittance of larger than 95% at a wavelength of 400 nm or 460 nm.
A third design example of an optical lens system 10c including nine lenses L1-L9 is described in detail below with reference to
Table 9 lists the internal transmittance of each of the lenses L1-L9 of the optical lens system 10c and the overall transmittance of all of the lenses L1-L9 at different wavelengths. Table 9 clearly shows each of the lenses L1-L9 may have an internal transmittance of larger than 95% at a wavelength of 380 nm or 400 nm.
A fourth design example of the optical lens system 10d including eight lenses L1-L8 is described in detail below with reference to
Table 12 lists the internal transmittance of each of the lenses L1-L8 of the optical lens system 10d and the overall transmittance of all of the lenses L1-L8 at different wavelengths. Table 12 clearly shows each of the lenses L1-L8 may have an internal transmittance of larger than 95% at a wavelength of 380 nm or 400 nm.
A fifth design example of the optical lens system 10e including eight lenses L1-L8 is described in detail below with reference to
Table 15 lists the internal transmittance of each of the lenses L1-L8 of the optical lens system 10e and the overall transmittance of all of the lenses L1-L8 at different wavelengths. Table 15 clearly shows each of the lenses L1-L8 may have a light transmittance of larger than 95% at a wavelength of 380 nm or 400 nm.
A sixth design example of the optical lens system 10f including eight lenses L1-L8 is described in detail below with reference to
Table 18 lists the internal transmittance of each of the lenses L1-L8 of the optical lens system 10f and the overall transmittance of all of the lenses L1-L8 at different wavelengths. Table 18 clearly shows each of the lenses L1-L8 may have an internal transmittance of larger than 95% at a wavelength of 380 nm or 400 nm.
A seventh design example of an optical lens system 10g including nine lenses L1-L9 is described in detail below with reference to
Table 21 lists the internal transmittance of each of the lenses L1-L9 of the optical lens system 10c and the overall transmittance of all of the lenses L1-L9 at different wavelengths. Table 9 clearly shows each of the lenses L1-L9 may have an internal transmittance of larger than 95% at a wavelength of 350 nm or 400 nm.
A eighth design example of an optical lens system 10h including nine lenses L1-L9 is described in detail below with reference to
Table 24 lists the internal transmittance of each of the lenses L1-L9 of the optical lens system 10c and the overall transmittance of all of the lenses L1-L9 at different wavelengths. Table 24 clearly shows each of the lenses L1-L9 may have a light transmittance of larger than 95% at a wavelength of 350 nm or 400 nm.
The simulated results are within permitted ranges specified by the standard, which indicates the optical lens system according to the above embodiments may achieve good imaging quality.
The following examples of optical lens systems 10i-10m describe another configuration where no cemented lens is provided and each of the lenses in the optical lens system may be a singlet lens. As prior developments have not taught or suggested, the inventors discover that a cemented lens, though being favorable for correcting optical aberrations, may cause defects in the transmission of short wavelength light, because the short wavelength light may damage the molecular bonding of an adhesive in the cemented lens to result in minor shift of lens pieces constituting the cemented lens. Particularly, a lower wavelength of light passing through a cemented lens, such as lower than 370 nm, may raise the possibility of damaging the molecular bonding of an adhesive in the cemented lens. Therefore, the optical lens system without the use of a cemented lens may have improved production reliability. Further, each of the optical lens systems 10i-10m may have a first lens group having negative refractive power and a second lens group having positive refractive power and includes at least one aspherical lens surface to reduce aberration. Besides, each of the optical lens systems 10i-10m may be adapted to transmit short wavelength light, such as ultraviolet at a wavelength of 350-420 nm, for imaging purpose. The optical lens system 10i-10m according to one embodiment may satisfy the following condition:
T(λ=365)>80%; and
TE(λ=365)>70%, where T(λ=365) denotes a transmittance of a lens material forming each of the lenses in the optical lens system, with the transmittance of the lens material being measured at a wavelength of 365 nm and a thickness of 10 mm, and TE(λ=365) denotes an overall transmittance of all of the lenses in the optical lens system measured at a wavelength of 365 nm. Further, at least one of the first lens group and the second lens group is moveable during focusing. Moreover, in the present and/or the other embodiment present in the specification, each of the lenses in the optical lens system may, but not essentially, be formed of a material having a transmittance larger than 80% measured at a wavelength of 365 nm and a thickness of 10 mm.
The design example of an optical lens system 10i is described in detail below with reference to
The detailed optical data of an optical lens system 10i are shown in Table 25, and the aspheric surface data are shown in Table 26 below.
Table 27 lists the internal transmittance of each of the lenses L1-L9 of the optical lens system 10i and the overall transmittance of all of the lenses L1-L9 at different wavelengths.
The detailed optical data of an optical lens system 10j illustrated in
Table 30 lists the internal transmittance of each of the lenses L1-L9 of the optical lens system 10j and the overall transmittance of all of the lenses L1-L9 at different wavelengths.
The detailed optical data of an optical lens system 10k illustrated in
Table 33 lists the internal transmittance of each of the lenses L1-L9 of the optical lens system 10k and the overall transmittance of all of the lenses L1-L9 at different wavelengths.
The detailed optical data of an optical lens system 10l illustrated in
Table 36 lists the internal transmittance of each of the lenses L1-L10 of the optical lens system 10l and the overall transmittance of all of the lenses L1-L10 at different wavelengths.
The detailed optical data of the an optical lens system 10m illustrated in
Table 36 lists the internal transmittance of each of the lenses L1-L11 of the optical lens system 10m and the overall transmittance of all of the lenses L1-L11 at different wavelengths.
Note the parameters listed in Tables 1-39 are only for exemplified purposes but do not limit the invention. It should be appreciated that variations about the design parameters or setting may be made in the embodiments by persons skilled in the art without departing from the scope of the invention. Therefore, any optical lens system of the same structure is considered to be within the scope of the present disclosure even if it uses different data. The embodiments depicted above and the appended drawings are exemplary and are not intended to limit the scope of the present disclosure.
The foregoing description of the preferred embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form or to exemplary embodiments disclosed. Accordingly, the foregoing description should be regarded as illustrative rather than restrictive. Obviously, many modifications and variations will be apparent to practitioners skilled in this art. The embodiments are chosen and described in order to best explain the principles of the invention and its best mode practical application, thereby to enable persons skilled in the art to understand the invention for various embodiments and with various modifications as are suited to the particular use or implementation contemplated. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents in which all terms are meant in their broadest reasonable sense unless otherwise indicated. Therefore, the term “the invention”, “the present invention” or the like does not necessarily limit the claim scope to a specific embodiment, and the reference to particularly preferred exemplary embodiments of the invention does not imply a limitation on the invention, and no such limitation is to be inferred. The invention is limited only by the spirit and scope of the appended claims. Moreover, these claims may refer to use “first”, “second”, etc. following with noun or element. Such terms should be understood as a nomenclature and should not be construed as giving the limitation on the number of the elements modified by such nomenclature unless specific number has been given. The abstract of the disclosure is provided to comply with the rules requiring an abstract, which will allow a searcher to quickly ascertain the subject matter of the technical disclosure of any patent issued from this disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Any advantages and benefits described may not apply to all embodiments of the invention. It should be appreciated that variations may be made in the embodiments described by persons skilled in the art without departing from the scope of the invention as defined by the following claims. Moreover, no element and component in the present disclosure is intended to be dedicated to the public regardless of whether the element or component is explicitly recited in the following claims.
This application is a continuation of U.S. patent application Ser. No. 16/821,253, filed Mar. 17, 2020, which is a continuation of U.S. patent application Ser. No. 14/981,691, filed Dec. 28, 2015, which is a continuation-in-part of U.S. patent application Ser. No. 14/750,569, filed Jun. 25, 2015, the entire disclosures of which are incorporated herein by reference.
Number | Name | Date | Kind |
---|---|---|---|
4770477 | Shafer | Sep 1988 | A |
5475537 | Kobayashi et al. | Dec 1995 | A |
5589988 | Suenaga | Dec 1996 | A |
5930032 | Maruyama et al. | Jul 1999 | A |
5999310 | Shafer et al. | Dec 1999 | A |
6115175 | Maruyama et al. | Sep 2000 | A |
6313955 | Yoneyama | Nov 2001 | B1 |
6956694 | Shafer et al. | Oct 2005 | B2 |
7057804 | Tada et al. | Jun 2006 | B2 |
7599127 | Muratani et al. | Oct 2009 | B2 |
7768719 | Jung et al. | Aug 2010 | B2 |
8279527 | Lin | Oct 2012 | B2 |
8498066 | Liu et al. | Jul 2013 | B2 |
9261670 | Lai et al. | Feb 2016 | B2 |
11448859 | Cheng | Sep 2022 | B2 |
20030155482 | Moellmann | Aug 2003 | A1 |
20060077564 | Baba | Apr 2006 | A1 |
20090296201 | Caldwell | Dec 2009 | A1 |
20130070123 | Imaoka | Mar 2013 | A1 |
20140185143 | Kubota | Jul 2014 | A1 |
20140185144 | Kubota | Jul 2014 | A1 |
20160154224 | Imai et al. | Jun 2016 | A1 |
Number | Date | Country | |
---|---|---|---|
20220382023 A1 | Dec 2022 | US |
Number | Date | Country | |
---|---|---|---|
Parent | 16821253 | Mar 2020 | US |
Child | 17883337 | US | |
Parent | 14981691 | Dec 2015 | US |
Child | 16821253 | US |
Number | Date | Country | |
---|---|---|---|
Parent | 14750569 | Jun 2015 | US |
Child | 14981691 | US |