TW201514552A - Optical filtering element capable of correcting spectrum aberration - Google Patents

Abstract

Disclosed is an optical filtering element capable of correcting spectrum aberration. It comprises a filter lens. The filter lens can change transmission beam, and eliminate optical path difference formed by incident light with different angles for correcting spectrum aberration. A dioptre lens is provided at one side of the filter lens. The dioptre lens can change transmitting direction of light, and collimate and modify light beam direction for carrying out image formation for modifying chromatic aberration caused by filter lens. Accordingly, it can be used in any optical imagery, illumination and projection system for simultaneously realizing selection of optical wavelength, control of light field intensity, pattern modulation, and modification of spectrum aberration without destruction of optical level of the original system. Uniformity and accuracy of chromaticity and lightness in optical image can be enhanced for achieving an effect of reducing measurement error effectively.

Description

Optical filter component capable of correcting spectral aberrations

The invention relates to an optical filter component capable of correcting spectral aberrations, in particular to a system which can be used in any optical imaging, illumination and projection system, and simultaneously realizes optical wavelength selection without destroying the optical level of the original system. The control of the intensity of the light field, the modulation of the field type and the correction of the spectral aberration, thereby improving the uniformity and correctness of the chromaticity and the brightness in the optical image, and achieving the effect of effectively reducing the measurement error.

According to the optical filter, it is a widely used optical component whose function is to intercept a specific optical wavelength for a broadband source.

In general, a common optical filter design is divided into a long-pass filter, a low-pass filter, a band-pass filter, etc.; the high-pass filter That is, only light of a higher wavelength is passed, and light of a low wavelength is blocked. The low-pass filter, on the other hand, only allows lower-wavelength light to pass through, but blocks high-wavelength light, and the band-pass filter is a mixture of the two, allowing only light in a specific wavelength range to pass. In addition, there are other optical filter designs, such as a band-reject filter, a neutral density filter (ND filter) or a laser line filter. Through the use of such a variety of filters, it can be effectively applied to a wide range of optical measurement technology, especially in the field of fluorescent imaging technology, and plays an important role, and the general filter, glass industry It is often made into a flat, fixed-width round or square product that makes it easy to use in a variety of optical systems.

In a generally visible infinite conjugate optical system (such as an optical complex microscope), the optical filter is placed in an optical path close to the parallel light to provide uniform and stable optical excitation and light collection, as exemplified by a common fluorescent microscope. The standard filter square is placed at the rear end of the infinitely conjugated objective lens and interposed in the area intersecting the collimated light source path, and the Exciter filter receives the white light homogenized by the light source through the convergence mirror group, and A wavelength source that excites the sample to fluoresce is filtered out. After the fluorescent sample is reflected by the dichroic mirror, after the fluorescent light is successfully excited, the scattered fluorescent light returns to the two-color lens, and the wavelength is high, and the principle is high pass and vice versa. Finally, in order to avoid the chance that the stray excitation light has incident on the sensor, a barrier filter is present to obtain a clean fluorescent message to facilitate the final fluorescence microscopic imaging. The example shows the importance and technical flexibility of the filter combination in optical applications. Since the imaging of the optical microscope is very demanding on the optical path, it is also important to see the placement of the filter. If the filter is placed in other parts, The position of non-parallel light is bound to cause serious interference with fluorescent images.

In a common finite conjugate optical system (such as an optical camera), the filter is usually placed at the front end of the camera lens. Commonly, there are colored glass, ND filter or Polarizer. The purpose is to act purely as the final filter before the sensor receives light to capture the desired optical information. In the case of fluorescence measurement, the optical path of the excitation light is usually not co-path with the camera, but the fluorescent material is illuminated laterally or backwards at the sample end, and the scattered light is excited by the fluorescence. The mode is expressed, and the camera lens directly receives the fluorescence and images it in the sensor. When the camera focuses on infinity, the optical image itself is not disturbed by the filter; however, if it is focused on a close object or when shooting a super wide-angle photo, the captured image itself will have problems, the reason The optical path length from the light source passing through the filter is inconsistent, which is not much different when photographing general life photos, but it may cause considerable errors when applied to scientific research.

There are three types of common optical filters, one is an Absorbing filter, one is an Interference filter, and the other is a Polarization filter. The absorption filter is The general glass is doped with metal ions or special compounds, and the wavelength of the passing light is partially filtered by absorption or scattering. According to Beer-Lambert-Bouguer law, the absorbing material is used. The penetration spectrum has a logarithmic intensity relationship with the thickness of the material; the thin film interference filter uses a multilayer film of 1/4 light wavelength thickness to form a filtering function by using an optical interference principle; and the polarization type filter By changing the physical properties of special materials and changing the spatial distribution of the light field, the filtering functions of these three are quite sensitive to the optical path of light traveling in the material. The absorption filter can be imagined as the thicker the light, the light The more scattered or absorbed ions are encountered between the materials, the smaller the light energy that penetrates, the wider the wavelength is cut off, and the thin film interference filter can be regarded as the incident angle of light. The change caused the optical path to be different from the thickness of the original design, so the range of the filtered spectrum of the raw material will also shift, and the polarizing filter also causes the difference in optical path because the incident angle of the light is not perpendicular to the incident. The phenomenon of depolarization is then formed, and the phenomenon of extinction spectrum distortion occurs.

Therefore, no matter what kind of optical filter, its optical properties are related to the length of the optical path that travels within the material. For a flat and fixed thickness standard filter, if a perfect uniform transmission spectrum is desired, the light source It must also be a perfectly collimated light source, or the filter can only be placed in the mid-end region of an infinitely conjugated optical system. In an infinitely conjugated optical system, the filter is placed in an optical path of approximately parallel light, So it doesn't have much impact. However, in a finite conjugate optical environment, if the light source is not collimated light, but is diverging beams or Converging Beams, it will be caused by the existence of an optical path difference. When the light passes through the filter, there are problems in the middle and the edge that the spectrum, the light intensity and the light field are different. In other words, the unevenness of the penetration spectrum will occur. If the optical axis of the filter is used as the standard, theoretically, the edges of the filter will have a vignetting angle, spectral shift and light field deformation. This phenomenon should be regarded as a spectral aberration (Spectrum Aberration).

In order to solve the various problems in the past, the inventors of this case have devoted themselves to research and development of an "optical filter element capable of correcting spectral aberrations" to effectively improve the disadvantages of the conventional use.

The main purpose of the present invention is to enable the selection of optical wavelengths, control of optical field intensity, field modulation and synchronization on any optical imaging, illumination and projection system without destroying the optical level of the original system. Correcting spectral aberrations, thereby improving the uniformity and correctness of chromaticity and brightness in optical images, and achieving the effect of effectively reducing measurement errors.

To achieve the above object, the present invention is an optical filter element capable of correcting spectral aberrations comprising: a filter lens for changing the transmitted light and eliminating the optical path difference formed when light of different angles is incident. As a correction of spectral aberrations.

In an embodiment of the invention, the filter lens has the characteristics of changing light intensity, spectral range or modulated light field distribution, and the material thereof can be at least multi-layer dielectric film, SiO ₂ doped glass material, polarization Made up of crystal or polymer material.

In an embodiment of the invention, the filter lens can be a single layer lens or a multilayer lens.

In an embodiment of the invention, the filter lens may be at least in the shape of a spherical mirror or an aspherical mirror.

In another embodiment, the optical filter component of the present invention for correcting spectral aberrations comprises: a filter lens, and a curved lens disposed on one side of the filter lens; the filter lens can change the transmitted light, and It can eliminate the optical path difference formed by different angles of light incident as a correction of spectral aberration, and the curved lens can change the transmission direction of the transmitted light, and can collimate and correct the direction of the beam for imaging. And can correct the chromatic aberration caused by the filter lens.

In an embodiment of the invention, the filter lens has the characteristics of changing light intensity, spectral range or modulated light field distribution, and the material thereof can be at least multi-layer dielectric film, SiO ₂ doped glass material, polarization Made up of crystal or polymer material.

In an embodiment of the invention, the filter lens can be a single layer lens or a multilayer lens.

In an embodiment of the invention, the filter lens may be at least in the shape of a spherical mirror or an aspherical mirror.

In an embodiment of the invention, the curved lens may be composed of at least a SiO ₂ doped glass material or a polymer neutral material.

In an embodiment of the invention, the curved lens can be a single layer lens or a multilayer lens.

In an embodiment of the invention, the curved lens may be at least in the shape of a spherical mirror or an aspherical mirror.

In one embodiment of the invention, the curved lens can be used to correct any optical chromatic aberration caused by the filter lens.

1‧‧‧ Optical filter elements for correcting spectral aberrations 11.‧‧ Filter lenses 12‧‧‧ Curved lenses 2‧‧‧Subjects 3‧‧‧Diverging beams through the filter lens 4‧‧‧ Collimated beam 5‧‧‧ camera lens 6‧‧‧Diffuse beam from the object 70‧‧‧The filament of the microscope source 71‧‧‧Light source 72‧‧‧Converging lens 73‧‧‧Small sample 74‧‧‧ Microscope Objectives 75‧‧•Microscopic eyepieces 76‧‧‧Photosensitive elements 80‧‧·Light source for projection system 81‧‧‧Digital/analog optical processor 82‧‧‧Modulated light 83‧‧‧Projection optical lens set 84 ‧‧‧Projection screen
A‧‧‧ center thickness
b‧‧‧Working distance
C‧‧‧ radius of curvature on both sides of the lens
D‧‧‧ divergence angle of divergent beam
e‧‧‧Optical path length
f‧‧‧Ideal design curve
G‧‧‧ Low cost design method
H1‧‧‧Spectral curve of light divergence angle 15 degrees
H2‧‧‧Spectral curve of light divergence angle 30 degrees
H3‧‧‧Spectral curve of light divergence angle 45 degrees
H4‧‧‧Spectral curve of light divergence angle 60 degrees
I1‧‧‧With the use of a filter lens, the red light level value curve obtained by the camera photosensitive element on the diagonal
i2‧‧‧Red light gradation curve obtained on the diagonal of the camera's photosensitive element in the case of a conventional fixed-thickness filter
J1‧‧‧With the use of a filter lens, the green light level value curve obtained by the camera photosensitive element on the diagonal
J2‧‧‧ Green light level numerical curve obtained on the diagonal of the camera photosensitive element in the case of a conventional fixed thickness filter

Fig. 1 is a schematic view showing an embodiment of a typical composition of the present invention applied to macro camera photography.
Fig. 2 is a schematic view showing the working principle of the filter lens of the present invention.
Figure 3 is a schematic view showing the radius of curvature of the filter lens in the lens of the present invention.
Figures 4-1 and 4-2 are schematic diagrams showing the theoretical results of the spectral aberration correction of the filter lens of the appropriate radius of curvature of the present invention.
Figures 5-1 and 5-4 are schematic diagrams showing actual experimental results of the present invention applied to a digital single-lens camera lens.
Figure 6 is a schematic view showing an embodiment of the optical filter element of the present invention for correcting spectral aberrations applied to a standard microscopic imaging system.
Fig. 7 is a schematic view showing an embodiment of an optical filter element for correcting spectral aberrations of the present invention applied to a projection optical system.

Please refer to FIG. 1 to FIG. 5-4 for a schematic diagram of an exemplary embodiment of the present invention applied to macro camera photography, a schematic diagram of the working principle of the filter lens of the present invention, and a display filter of the present invention. The schematic diagram of the theoretical results of the curvature of the lens on the lens, the filter lens of the appropriate radius of curvature of the present invention, and the actual experimental results of the present invention applied to the digital monocular camera lens. As shown in the figure, the optical filter component 1 for correcting spectral aberrations can be directly formed by the filter lens 11 or a filter lens 11 and a curved lens 12.

The above-mentioned filter lens 11 can change the transmitted light and can eliminate the optical path difference formed when light of different angles is incident as a correction of spectral aberration, wherein the filter lens 11 has a change in light intensity. The spectral range or the characteristics of the modulated light field distribution, and the material may be composed of at least a plurality of dielectric thin films, SiO ₂ doped glass materials, polarizing crystals or polymer materials, and the filter lens 11 may be a single layer A lens or a multilayer lens, and the filter lens 11 can be at least in the shape of a spherical mirror or an aspherical mirror.

The curved lens 12 is disposed on the side of the filter lens 11 (for example, can be disposed at the front end of the filter lens 11), can change the transmission direction of the transmitted light, and can collimate and correct the direction of the light beam for imaging. Any optical chromatic aberration caused by the filter lens 11 can be corrected, wherein the curved lens 12 can be composed of at least a SiO ₂ doped glass material or a polymer neutral material, and the curved lens 12 can be a single a layer lens or a multilayer lens, and the curved lens 12 can be at least in the shape of a spherical mirror or an aspherical mirror, and the curved lens 12 can be changed in different shapes according to optical requirements, including at least microscopic, macro, wide-angle and telescopic Imaging for other optical purposes. If so, a new optical filter element capable of correcting spectral aberrations is constructed by the above structure.

When the present invention is applied, any lens arrangement or combination can be performed by at least one piece of the filter lens 11 and the curved lens 12 according to the needs and purposes of the optical system, and the manner of use thereof is at least applied to the camera or Optical imaging systems for microscopes, spectroscopic systems for cameras or microscopes, spectral homogenization of projections, illumination systems, measurement systems for polarization optics or sample substrate shapes.

The curved lens 12 can increase the magnification of the optical imaging to provide the function of macro photography, and collimate the diverging beam 3 from the object 2 and passing through the filter lens 11, and correct any damage caused by the filter lens 11. Chromatic aberration; the filter lens 11 has the physical characteristics of optical filtering, which can select or control the wavelength range of the light beam, the intensity of the light field and the polarization, etc. by the lens material, and achieve different appropriate structures by different curved surfaces. Correction of the spectral aberration; then, the collimated beam 4 will enter the general camera lens 5, and then the photosensitive element will be imaged, and the composition of at least two lenses described above and the camera lens can be synchronously achieved. The purpose of optical imaging, filtering, modulating light and spectral aberration correction.

However, the working principle of the filter lens 11 (as shown in FIG. 2) is that the center thickness a is the thickness of the filter lens 11 on the optical axis, and the working distance b is the standard working distance of the lens. When the diverging beam 6 of the object 2 enters the filter lens 11, the interface refraction phenomenon occurs due to the difference between the material of the filter lens 11 and the ambient refractive index. If the radius of curvature c of both sides of the filter lens 11 is appropriately designed, Regardless of the divergence angle d of the divergent beam, the optical path length e of the light traveling in the filter lens 11 can be equal to the center thickness a, which means that when a divergent beam 6 enters the filter lens 11, there will be no optical path. The existence of the difference means that the optical properties of the light penetrating the filter lens 11 will be very uniform, and the conditions of different light intensity, spectral shift or light field deformation will not occur.

Further, as shown in Fig. 3, it shows an embodiment in which the radius of curvature of the filter lens 11 is on the lens design; the beam having the same divergence angle can have the same optical path length after entering the filter lens 11, the filter The radius of curvature of the lens 11 needs to be calculated very accurately. The vertical axis in the figure is the different length values of the radius of curvature of the two sides of the filter lens 11. The horizontal axis is the different angle values of the divergent beam. According to the theoretical calculation, the zero light can be perfectly satisfied. The lens of the path difference should conform to the ideal design curve f, which means that the radius of curvature of both sides of the filter lens 11 needs to be larger as the divergence angle of the divergent beam becomes larger, which means that the filter lens 11 needs to be made into an aspherical shape. In the case of cost considerations and production feasibility, it is also appropriate to select a radius of curvature of a fixed value that does not change with the divergence angle of the divergent beam, ie, a low-cost design method g, to achieve an incomplete but relative Still, the spectral aberration of the excellent aberration is corrected, and the filter lens 11 conforming to this condition has a spherical shape.

Figure 4-1 shows the transmission spectrum of a divergent beam passing through a conventional fixed-thickness filter, and Figure 4-2 shows the transmission spectrum of a divergent beam passing through the filter lens 11. The horizontal axis of the two figures is The wavelength, the vertical axis is the normalized transmitted light intensity, and the curves h1, h2, h3, and h4 represent the spectral curves of the light divergence angles of 15 degrees, 30 degrees, 45 degrees, and 60 degrees, respectively. It is known that the transmission spectrum of the conventional fixed-thickness filter will be significantly different with the difference of the light divergence angle, and the filter lens 11 will not have this problem, and the conclusion can provide theoretical evidence for this creation.

Figures 5-1 to 5-4 show one of the actual experimental results of the optical filter element 11 applied to a general monocular camera lens, and Figure 5-1 shows a conventional fixed thickness filter with a curved lens. Photographs, Fig. 5-2 are photographs taken using an optical filter element 1 that corrects spectral aberrations. The two filter materials are the same high-pass glass with a cut-off wavelength of 530 nm, through which the two images are aligned. It can be seen that the 5-1 has a more severe vignetting and edge color shift, and therefore, it can be seen that the filter lens 11 of the present invention can provide significant spectral aberration correction compared to a conventional fixed thickness filter. In order to quantify the experimental results, enough photos of the same type are sampled and their total value statistics are taken as the exact numerical comparison evidence. Figures 5-3 and 5-4 show the pair of camera photosensitive elements, respectively. The average red (R) and green (G) gradation spectra obtained on the angular line, the horizontal axis in the figure is the position of each pixel point on the diagonal line of the camera photosensitive element, and the vertical axis is the average gradation value. The blue (G) spectrum is not shown here because the high-pass filter has filtered light sources with wavelengths below 530 nm, so the value is always zero. The curve i1 and the curve j1 indicate that the red (R) and green (G) gradation values are obtained on the diagonal of the camera photosensitive member in the case where the filter lens 11 is used, and the curve i2 and the curve j2 are indicated in use. In the case of a conventional fixed-thickness filter, red (R) and green (G) gradation values are obtained on the diagonal of the camera photosensitive element. The results of this experiment show that the curves i1 and j1 are flat in the edge region relative to the curves i2 and j2, which means that the use of the filter lens 11 will result in a more consistent spectral transmittance for the digital monocular camera.

See Figure 6 for an example of an optical filter component that can correct spectral aberrations applied to a standard microscopy imaging system. As shown in the figure: when the filament 70 of the microscope source emits the light source 71, it is concentrated by the condenser lens 72 and illuminating on the minute sample 73. If there is a need for filtering before the incident of the small sample 73, the microscope source can be used. An optical filter element 1 for correcting spectral aberration is placed between the filament 70 and the condenser lens 72, or an optical filter element 1 for correcting spectral aberration is inserted between the minute sample 73 and the condenser lens 72, which still has The original function of the filter can correct problems of different light intensities, spectral shifts, light field distortion or chromatic aberration.

After the tiny sample 73 is illuminated, it can be harvested by the microscope objective 74, and the beam will then be transmitted to the microscopic eyepiece 75 for convergence, and imaged by the photosensitive element 76, if the microscope objective 74 and the microscopic eyepiece 75 are If there is no space to re-insert any optical filter element, then a correctable spectral aberration can be inserted between the minute sample 73 and the microscope objective 74, or between the microscopic eyepiece 75 and the photosensitive element 76. The optical filter element 1 performs the filtering function thereof, and can correct the problem of different light intensity, spectral shift, light field deformation or chromatic aberration, and the position of the optical filter element 1 which can correct the spectral aberration An optical path region that can be located in any non-collimated beam in the microscope, which can be interleaved with a general filter that is specifically placed in the optical path region of the collimated beam, or mixed in any manner, such as an optical polarizer that produces bias and depolarization, Fluorescent multi-wavelength filter cubes and more. To achieve any desired optical measurement in a limited optical path space, and to reduce any optical errors caused by optical path differences in the material.

Refer to Figure 7 for an example of an optical filter component that can correct spectral aberrations applied to a projection optical system. As shown in the figure: after the light source 80 of the projection system exits the beam and passes through the digital/analog optical processor 81, the modulated light 82 projects the image onto the projection screen 84 by the projection optical lens group 83, which is similar to the optical path concept of FIG. An optical filter element 1 for correcting spectral aberrations can be placed in the optical path region of any non-collimated light in the optical system so as to have the original function of the filter and can correct different light intensity, spectral shift, and light field. Problems with distortion or chromatic aberration, or adding special optical purposes such as beam expansion, doubling, and so on.

The digital/analog optical processor 81 can also be replaced by a pure object, a mask or an image, and the optical filter component 1 for correcting spectral aberrations should also be included in the digital/analog optical processor 81. a portion, or a portion of the projection optical lens set 83; in addition, the digital/analog optical processor 81 can be a transmissive or reflective component, such as an analog liquid crystal component or a digital micromirror component, as shown in FIG. The optical path architecture not only includes the digital/analog optical processor 81 as a penetrating form, but also includes an optical path architecture in which the digital/analog optical processor 81 is in a reflective form.

Therefore, it can be seen from the above description that the curved lens 12 of the present invention can be applied to a suitable area in any optical system to provide additional optical functions or to correct any optical caused by the presence of the filter lens 11. Chromatic aberration. The filter lens 11 is disposed on the curved lens 12, and its function is to replace the traditional optical filter, and the lens structure compensates the distance of the non-collimated light beam after entering the medium, thereby eliminating the existence of the optical path difference. Thus, spectral aberrations can be effectively eliminated, providing good and uniform penetration spectrum information. And corresponding to different optical systems, the number and design of the lenses can be individually adjusted to achieve optimization, and the invention should be included in systems or components such as imaging, spectroscopy, illumination, projection, polarization, substrate construction, etc. according to the needs of use. application.

In summary, the optical filter component of the present invention, which can correct spectral aberrations, can effectively improve various disadvantages of the conventional use, can be used on any optical imaging, illumination and projection system, and can be synchronized without destroying the optical level of the original system. Achieve optical wavelength selection, control of light field intensity, field modulation and correction of spectral aberrations, thereby improving the uniformity and correctness of chromaticity and brightness in optical images, thereby achieving the effect of effectively reducing measurement errors; The invention can be more progressive, more practical, and more in line with the needs of consumers. It has indeed met the requirements of the invention patent application, and has filed a patent application according to law.

However, the above is only the preferred embodiment of the present invention, and the scope of the present invention is not limited thereto; therefore, the simple equivalent changes and modifications made in accordance with the scope of the present invention and the contents of the invention are modified. All should remain within the scope of the invention patent.

1‧‧‧ Optical filter components that correct spectral aberrations

11‧‧‧ filter lens

12‧‧‧ Curved lens

2‧‧‧Photographed objects

3‧‧‧Diverging beam through the filter lens

4‧‧‧ is collimated beam

5‧‧‧ camera lens

Claims (12)

An optical filter component that corrects spectral aberrations, including:
A filter lens can change the transmitted light and eliminate the optical path difference formed by the incident of different angles of light as a correction of the spectral aberration. An optical filter element capable of correcting spectral aberration according to claim 1 of the patent application, wherein the filter lens has characteristics of changing light intensity, spectral range or modulated light field distribution, and at least the material of the filter can be electric-coated film, SiO ₂ of doped glass material, crystal or polarizing material composed of a polymer. The optical filter element of the spectral aberration correction according to claim 1 or 2, wherein the filter lens can be a single layer lens or a multilayer lens. The optical filter element for correcting spectral aberration according to the first or second aspect of the patent application, wherein the filter lens is at least in the shape of a spherical mirror or an aspherical mirror. An optical filter component that corrects spectral aberrations, including:
A filter lens that changes the transmitted light and eliminates the optical path difference formed by the incident light at different angles as a correction for spectral aberrations; and a curved lens that is attached to the lens side of the filter , can change the direction of transmission of the transmitted light, and can collimate and correct the direction of the beam for imaging, and can correct the chromatic aberration caused by the filter lens. An optical filter element capable of correcting spectral aberrations according to claim 5, wherein the filter lens has characteristics of changing light intensity, spectral range or modulated light field distribution, and at least the material of the plurality of layers can be It consists of an electro-chemical film, a SiO ₂ doped glass material, a polarizing crystal or a polymer material. The optical filter element for correcting spectral aberration according to the fifth or sixth aspect of the patent application, wherein the filter lens can be a single layer lens or a multilayer lens. The optical filter element for correcting spectral aberration according to the fifth or sixth aspect of the patent application, wherein the filter lens is at least in the shape of a spherical mirror or an aspherical mirror. The optical filter element capable of correcting spectral aberration according to claim 5, wherein the curved lens is composed of at least a SiO ₂ doped glass material or a polymer neutral material. The optical filter element for correcting spectral aberration according to the fifth or the ninth aspect of the patent application, wherein the curved lens can be a single layer lens or a multilayer lens. The optical filter element for correcting spectral aberration according to the fifth or the ninth aspect of the patent application, wherein the curved lens is at least in the shape of a spherical mirror or an aspherical mirror. An optical filter element for correcting spectral aberrations as described in claim 5 or claim 9, wherein the curved lens can be used to correct any optical chromatic aberration caused by the filter lens.