Technique and apparatus for spectrophotometry using broadband filters

Abstract

A spectrophotometer is provided, which comprises a receiving part diffusing an incident light, a first broadband filter group, and a detector detecting the light having passed through the first broadband filter group, in order to easily select and detect a plurality of lights having specific wavelengths, wherein the first broadband filter group comprises a first broadband filter arranged to have a first angle with respect to an incident direction of light to enable the incident light to pass through a first wavelength band, a second broadband filter arranged to have a second angle, which is different from the first angle, with respect to an incident direction of light to enable the light having passed through the first broadband filter to pass through a second wavelength band, and a first path compensation means for adjusting a path of the light having passed through the second broadband filter to be identical to a path of the light having passed through the first broadband filter, wherein the first broadband filter, the second broadband filter and the first path compensation means are arranged in series with respect to the incident direction of light. Accordingly, it is possible to increase the efficiency of the outputted light compared to the incident light, and to detect a plurality of lights having the desired specific wavelengths at the same time.

Claims

1. A spectrophotometer for analyzing a light having a specific wavelength band from an incident light, the spectrophotometer comprising: a receiving part diffusing an incident light from one side at the other side, wherein the receiving part is configured of a rod or a concave lens, which can diffuse an incident light; a first broadband filter group; a second broadband filter group; and a detector detecting the light having passed through the first broadband filter group, wherein the first broadband filter group comprises a first broadband filter arranged to have a first angle with respect to an incident direction of light to enable the incident light to pass through a first wavelength band; a second broadband filter arranged to have a second angle, which is different from the first angle, with respect to an incident direction of light to enable the light having passed through the first broadband filter to pass through a second wavelength band; and a first path compensation means for adjusting a path of the light having passed through the second broadband filter to be identical to a path of the light having passed through the first broadband filter, wherein the first broadband filter, the second broadband filter and the first path compensation means are arranged in series with respect to the incident direction of light, wherein the second broadband filter group comprises a third broadband filter arranged to have a third angle with respect to an incident direction of light to enable the incident light to pass through a third wavelength band; a fourth broadband filter arranged to have a fourth angle, which is different from the third angle, with respect to an incident direction of light to enable the light having passed through the third broadband filter to pass through a fourth wavelength band; and a second path compensation means for adjusting a path of the light having passed through the third broadband filter to be identical to a path of the light having passed through the fourth broadband filter, wherein the third broadband filter, the fourth broadband filter and the second path compensation means are arranged in series with respect to the incident direction of light, and wherein the first broadband filter group and the second broadband filter group are arranged, when viewed from a side, in a straight line in a direction perpendicular to the incident direction of light.

2. The spectrophotometer of claim 1, further comprising N broadband filter groups which are arranged, when viewed from a side, in a straight line with the first broadband filter group and the second broadband filter group in a direction perpendicular to the incident direction of light, wherein 1N28.

3. The spectrophotometer of claim 2, wherein the detector is an image sensor.

4. The spectrophotometer of claim 1, wherein the receiving part comprises a first receiving part and a second receiving part; a light is incident to the first broadband filter group from the first receiving part; and a light is incident to the second broadband filter group from the second receiving part.

5. The spectrophotometer of claim 1, further comprising at least one or more lens between the first broadband filter group and the detector for preventing interference, the at least one or more lens comprising at least one of: a cylindrical lens; a convex lens; or any combination thereof.

6. The spectrophotometer of claim 1, wherein the detector is an image sensor.

7. The spectrophotometer of claim 1, further comprising at least one or more lens between the first broadband filter group and the detector for preventing interference, the at least one or more lens comprising at least one of: a cylindrical lens; a convex lens; or any combination thereof.

8. The spectrophotometer of claim 1, wherein the detector is an image sensor.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 represents the conventional monochromator having a diffraction grid.

(2) FIGS. 2 (a) to (d) represent exemplary results of the permeated wavelength band according to the rotational angle of the broadband filter.

(3) FIG. 3a represents the spectrophotometer according to an embodiment of the present invention.

(4) FIG. 3b represents the changes in the size and the shape of the light source in the spectrophotometer according to FIG. 3a.

(5) FIG. 4 illustrates the fundamentals of the compensation unit included in the spectrophotometer of the present invention.

(6) FIG. 5a represents the spectrophotometer according to an embodiment of the present invention.

(7) FIG. 5b represents the changes in the size and the shape of the light source in the spectrophotometer according to FIG. 5a.

(8) FIG. 6a illustrates the process of the selection of a specific wavelength according to an embodiment of the present invention.

(9) FIG. 6b illustrates the fundamentals of using two broadband filters to select a specific wavelength according to an embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

(10) Regarding the embodiments of the present invention in this text, particular structural and functional explanations are merely examples for the purposes of explaining the embodiments of the present invention, and the embodiments of the present invention can be carried out in various forms and shall not be construed as being limited to the embodiments described in this text.

(11) The present invention can have various modifications and forms, and thus specific embodiments are described in this text in detail with examples in drawings. However, this is not purported to limit the present invention to a specific disclosed form, but it shall be understood to include all modifications, equivalents and substitutes within the idea and the technological scope of the present invention.

(12) The terminology used in the present invention is used for the purposes of explaining the specific embodiment only, and it is not intended to limit the present invention. Singular expressions shall include the plural expressions unless expressly meant otherwise in context. In the present invention, it shall be understood that the terms such as comprise/include or have etc., are intended to designate the presence of the feature, number, step, movement, component, part or their combination, and not excluding the presence or possibility of addition of one or more of other features or numbers, steps, movements, components, parts or their combinations beforehand.

(13) Unless defined otherwise, including the technical or scientific terms, all terms used here mean the same as generally understood by a skilled person in the art to which the present invention pertains. The terms that are used generally as defined in a dictionary, shall be construed as the meaning consistent with the meaning in the context of the related technology, and unless the present invention expressly defines otherwise, they shall not be construed as having ideal or excessively typical meaning.

(14) In this text, the preferable embodiment of the present invention will be explained in more detail with reference to the attached drawings. For the identical components on the drawings, identical reference numerals shall be used, and any overlapping description of the identical component shall be omitted.

(15) FIGS. 2 (a) to (d) represent exemplary results of the passed wavelength range according to the rotational angle of the broadband filter of FIG. 2. Specifically, FIG. 2(a) illustrates the case in which the light is passed with the angle of the broadband filter with respect to the incident direction of the light arranged in 90, and the exemplary result of the passed light is illustrated in FIG. 2(b). Referring to FIG. 2(b), where the light is passed with respect to the angle of the broadband filter with respect to the incident direction of the light arranged in 90, it can be seen that only the light with the central wavelength of 628 nm and a bandwidth of certain width is passed. Moreover, FIG. 2(c) is a case in which the light is passed with the angle of the broadband filter with respect to the incident direction of the light arranged in 30, and as shown in FIG. 2(d), it can be seen that only the light with the central wavelength of 562 nm and a bandwidth of certain width is passed. As such, the broadband filter used in the present invention can be a bandwidth passing filter having a different central wavelength according to the angle of the broadband filter with respect to the incident direction of the light. Moreover, a bandwidth passing filter having a different central wavelength and bandwidth according to the angle with respect to the incident direction of the light can also be used.

(16) FIG. 3a represents the spectrophotometer according to an embodiment of the present invention. The spectrophotometer according to this embodiment comprises a receiving part (300) that distributes the incident light. The incident light from the light source is diffused as it passes through the receiving part (300), and the diffused light is incidentally irradiated to the first broadband filter group that will be described later. As the receiving part (300) of the spectrophotometer of the present invention, for example, optical fiber, a rod, a concave lens, etc. can be used. In addition to them, a material that can diffuse the incident light can also be used as the receiving part. The light that passed through the receiving part is diffused and is incidentally irradiated to the broadband filter group. Accordingly, the spectrophotometer of the present invention does not need a separate rotating device for changing the rotational angle of the broadband filter, etc.

(17) The spectrophotometer according to this embodiment comprises a first broadband filter group consisting of a first broadband filter (310) that has a first angle (.sub.1) with respect to the incident direction of the light, a second broadband filter (320) that has a second angle (.sub.2) with respect to the incident direction of the light, and a compensation unit (330). Also, the spectrophotometer according to this embodiment comprises a detector (350) that detects the light that passed through the first broadband filter group. The incident light L passes through the first broadband filter (310) and becomes the light L1 having only a wavelength of a predetermined bandwidth according to the first angle (.sub.1). The light L1 passes through the second broadband filter (320) having the second angle (.sub.2) with respect to the incident direction of the light, and becomes the light L2 having only the common wavelength band among the bands that passed through the first broadband filter and the second broadband filter as its wavelength.

(18) Meanwhile, FIG. 4 illustrates the fundamentals of the compensation unit included in the spectrophotometer of the present invention. When the light passes through the broadband filters, the route of the light varies depending on the thickness, number, incident angle, etc. of the filter. For example, L1 and L2 that passed through the first broadband filter and the second broadband filter have a difference in route compared to the incident light L as illustrated in FIG. 4. As such, if the route of the light varies every time the thickness, number, angle, etc. of the broadband filter vary, it can be a significant restriction on using various combinations of the broadband filters for selecting various scopes of wavelength. Thus, the spectrophotometer of the present invention comprises the compensation unit (330), and thus adjusts the route of the light so that the change in the route of the light incurred by passing through the first broadband filter and the second broadband filter is identical to that in the route of the light before passing through the broadband filters. Thus, the light L3 which passed through the compensation unit (330) has only the wavelength band that passed through both the first broadband filter and the second broadband filter, and at the same time, has the same light route as the incident light L which did not pass through the broadband filters.

(19) As an embodiment, at least one or more lens can be arranged between the compensation unit (330) and the detector (350) for preventing interference. In the spectrophotometer of FIG. 3a which comprises a broadband filter group, a convex lens (340) can be used. FIG. 3b represents the changes in the size and the shape of the light source in each of its progressing stages. The light (L3) that is irradiated after passing through the compensation unit (330) converges while being refracted as it passes through the convex lens (340). By arranging a detector (350) in the location where the refracted light (L4) converges, light can be detected more easily.

(20) FIG. 5a represents the spectrophotometer according to another embodiment of the present invention. The spectrophotometer according to this embodiment further comprises, in addition to the spectrophotometer of FIG. 3a, a second broadband filter group consisting of a third broadband filter (412) that has a third angle (.sub.3) with respect to the incident direction of the light, a fourth broadband filter (422) that has a fourth angle (.sub.4) with respect to the incident direction of the light, and a second compensation unit (432). The first and the second broadband filter groups are arranged, when viewed from a side, in a straight line in a direction perpendicular to the incident direction of light.

(21) As an embodiment, at least one or more lens can be arranged between the compensation unit (431, 432) and the detector (460) for preventing interference. In the spectrophotometer of FIG. 5a which comprises two broadband filter groups, a cylindrical lens (440) and a convex lens (450) can be used. FIG. 5b represents the changes in the size and the shape of the light source in each of its progressing stages. Each light (L3) that is irradiated after passing through the compensation unit (431, 432) becomes an oval shape as it passes through the cylindrical lens (440), and converges after passing through the convex lens (450). By arranging a detector (460) in the location where the light (LA) that passed through the convex lens (450) converges, light can be detected more easily.

(22) Also, the spectrophotometer of the present invention can further comprise N (1N28) broadband filter groups that are arranged, when viewed from a side, in a straight line in a direction perpendicular to the incident direction of light, in addition to the first broadband filter group and the second broadband filter group. By arranging a plurality of broadband filter groups having different angles with respect to the incident direction of light, separated lights in the number of the broadband filter groups which have different wavelengths from one another can be detected at the same time.

(23) As an embodiment, the spectrophotometer of the present invention can comprise a plurality of optical fibers that distribute the light source. For example, the spectrophotometer illustrated in FIG. 5a can comprise a first optical fiber that makes the light incident to the first broadband filter group, and a second optical fiber that makes the light incident to the second broadband filter group. The number of the optical fibers is not limited to this, but the optical fibers can be included by the number of the broadband filter groups to distribute the light source.

(24) In the spectrophotometer of the present invention, different types of detectors can be used. For example, detectors such as an image sensor, a PMT (photomultiplier tube), a CCD (Charge Coupled Device) array detector, a CMOS detector, a photodiode array detector, etc. can be used, and are not limited to them.

(25) FIG. 6a illustrates the process of the selection of a specific wavelength according to an embodiment of the present invention. The light L with a wavelength of broad bandwidth is provided with the monochromator. The first broadband filter works as the first bandwidth passing filter having the central wavelength .sub.c1 and the bandwidth d.sub.1 when it is arranged to have the angle .sub.1 with respect to the incident direction of the light. The light L1 is the result of the Light L passing through the first broadband filter with the angle .sub.1, and it has the central wavelength .sub.c1 and the bandwidth d.sub.1. The second broadband filter works as the second bandwidth passing filter having the central wavelength .sub.c2 and the bandwidth d.sub.2 when it is arranged to have the angle .sub.2 with respect to the incident direction of the light. Only the part of the wavelength of the light L1 corresponding to the second bandwidth passing filter passes and becomes the light L2. In this regard, FIG. 6b illustrates the fundamentals of selecting a specific wavelength by letting the light pass through the broadband filter with the central wavelength .sub.c1 and the bandwidth d.sub.1, and the broadband filter with the central wavelength .sub.c2 and the bandwidth d.sub.2. By such fundamentals, the light L2 ultimately has the central wavelength .sub.c and the bandwidth d, and here, each of .sub.c and d is derived by the following equation 1 and equation 2.
.sub.c=(.sub.c1+.sub.c2)|d.sub.1d.sub.2|[Equation 1]
d=(d.sub.1+d.sub.2)|.sub.c1.sub.c2|[Equation 2]

(26) The spectrophotometer of the present invention, by the fundamentals as above, can freely select the desired wavelength by adjusting the angles of the broadband filters with respect to the incident direction of the light and varying the central wavelength and the bandwidth of the wavelength bandwidth being passed. Also, by using a plurality of broadband filter groups, it can detect light of a plurality of wavelengths at the same time.

(27) As above, the present invention is described with reference to a preferred embodiment, but a skilled person in the art would understand that the present invention may be modified and changed variously within the scope not exceeding the idea and the field of the present invention described in the below claims.