JP2008134132A - Total reflection absorption spectrum measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a total reflection absorption spectrum measuring device equipped with a means capable of switching an ATR observation mode to/from a visual observation mode accurately with a simple mechanism. <P>SOLUTION: This total reflection absorption spectrum measuring device equipped with a reflection object optical system comprising a concave main mirror 2 and a convex sub-mirror 3, and an ATR prism 4 having a total reflection face on a converging point of the optical system, has a constitution wherein a holder 7 for holding the ATR prism 4 is mounted on a rotating shaft 6, and the rotating shaft 6 is formed so as to be rotated around a horizontal line on the sample surface S placed on the under surface of the ATR prism 4, and the ATR prism 4 can be inverted and moved from a sample measuring position to a retracting position on the upside by rotating the rotating shaft 6. The device has a structure wherein a light transmission means (for example, a hole) 11 for allowing passage of measuring light when the ATR prism 4 is on the retracting position is formed on the holder. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a total reflection absorption spectrum measuring apparatus widely used for organic substances such as polymer materials, qualitative analysis and fixed analysis of various substances, and in particular, an optical system for measuring an infrared spectrum of a sample, The present invention relates to a total reflection absorption spectrum measuring apparatus for an infrared microscope provided with an optical system for observing a sample with visible light.

  In the total reflection absorption spectrum measurement method (ATR), a transparent body having a higher refractive index than that of the sample is brought into contact with the sample surface, and measurement light is emitted from the high refractive index transparent body side at an incident angle at which total reflection occurs at the interface with the sample. When measuring infrared light with a method of measuring the absorption characteristics of the sample by detecting the absorption attenuation due to the sample of the light that has been incident and totally reflected, the infrared configured by the reflective optical system is used. An apparatus using a reflection microscope system is used.

  FIG. 5 shows the structure of an objective mirror of a conventional infrared reflection microscope system. The objective mirror is composed of a concave primary mirror 12 having a hole in the center and a convex secondary mirror 13 coaxial with the concave primary mirror 12, and monochromatic measuring light (or interferometer) emitted from a spectrometer (or interferometer) (not shown). (Or all-wavelength light modulated by the interferometer) is incident on the objective optical system below the right half of the optical axis in FIG. 5, and the light is reflected by the convex secondary mirror 13 and the concave primary mirror 12 to be objective. The light is condensed at a condensing point P of the mirror optical system. A hemispherical ATR prism 14 centered at point P is disposed at the condensing point P, and the sample is brought into contact with the lower surface of the ATR prism 14. In this way, the measurement light focused on the point P is not bent by the ATR prism 14, but is collected directly on the point P, is totally reflected by the sample surface, and goes up the left half of the optical axis of the objective optical system. Is done.

Since the total reflection absorption spectrum measurement method (ATR) uses total reflection, if the prism is at the focal position, all the light is reflected from the bottom surface of the ATR prism, and the sample at the focal position cannot be visually observed. . Therefore, it is necessary to move the prism to another place and to pass the measurement light through the condensing point instead of visible observation or measurement without using the prism. Therefore, conventionally, as shown in FIGS. 6, 7, and 8, the ATR prism 14 and the hole 17 for passing the measurement light are provided in the turntable 15 or the slide plate 16 that rotates around the shaft 18, The turntable 15 or the slide plate 16 is switched by rotating or sliding on the sample on the same horizontal plane. This switching method using a turntable is also disclosed in FIG.
JP 2001-133400 A

  Since the rotation method by the turntable and the slide method by the slide plate are horizontally moved on the same plane horizontal to the sample, the ATR prism is always placed at the same height as the focal position. The fact that the ATR prism does not move in the vertical direction along the optical axis, that is, the focus direction, is advantageous for the position reproducibility when the ATR prism is moved to the use position, but the sample or the sample is not intended by the user. There is a risk of accidentally touching other things such as a mounting table, applying an undesired pressure to the ATR prism and the sample, and destroying them in the worst case. If the ATR prism is left exposed when not in use, the ATR prism may be damaged, so measures such as attaching a protective cover to the prism or removing it completely when not in use may be taken. It is very troublesome in operation.

  Therefore, in view of solving the above problems, the present invention provides a total reflection absorption spectrum measuring apparatus provided with means capable of accurately switching between an ATR observation mode and a visible observation mode with a simple mechanism. For the purpose.

  In order to solve the above problems, the present invention provides a total reflection absorption spectrum measurement comprising a reflective objective optical system comprising a concave primary mirror and a convex secondary mirror, and an ATR prism having a total reflection surface at the condensing point of the optical system. In the apparatus, a holder for holding the ATR prism is attached to a rotation shaft, and the rotation shaft is formed to rotate around a horizontal line on a sample surface placed on the lower surface of the ATR prism, and rotates the rotation shaft. Accordingly, the ATR prism can be reversed and moved from the sample measurement position to the upper retracted position. When the ATR prism is in the retracted position, the light transmitting means (for example, a hole) that allows the measurement light to pass therethrough is the holder. It was set as the structure formed in.

Here, it is preferable to form a hole as the light transmitting means, but other methods (for example, attaching a light transmitting member) may be used as long as the measuring light can be transmitted.
The hole for passing measurement light formed in the holder is preferably made as large as possible as long as the strength of the holder allows. For example, two large holes should be formed symmetrically. The hole can also be formed of a light transmissive material such as transparent glass.

  According to the present invention, when performing a visual observation or measurement without using the ATR prism, the ATR prism can be easily switched between the sample measurement position and the retracted position by a simple operation by rotating the rotation shaft. When the ATR prism is moved to the retracted position, the ATR prism can be held in an inverted state, which is the back of the reflecting objective mirror, so that it is possible to reduce damage to the ATR prism inadvertently by the user. In addition, when returning the ATR prism to the use position, the ATR prism moves with respect to the sample from above with a circular trajectory. Can do. In addition, since the movement of the ATR prism is performed by the rotation of the rotating shaft, the focal position is always determined when the ATR prism is returned to the use position, so that a good reproducibility of the ATR prism position can be obtained. There is an excellent effect of being able to.

(Means and effects for solving other problems)
In the above invention, the ATR prism is preferably mounted at a position eccentric with respect to the rotation axis of the rotation axis.
Thus, the ATR prism can be formed with a simple structure so as to be able to reversely move from the sample measurement position to the upper retracted position.

In the above invention, it is preferable to provide a positioning mechanism for temporarily holding the ATR prism at a sample measurement position and a retracted position.
As a result, the ATR prism can be accurately held at the sample measurement position and the retracted position set in advance.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments described below, and it goes without saying that various aspects are included without departing from the spirit of the present invention.

  1 is a cross-sectional view of a reflection objective mirror of a total reflection absorption spectrum measuring apparatus according to an embodiment of the present invention, FIG. 2 is an enlarged cross-sectional view of an ATR prism portion, and FIG. 3 is an inversion of the ATR prism to a retracted position. FIG. 4 is an enlarged perspective view of the ATR prism portion when reversed and moved to the retracted position, and FIG. 5 is provided with a conventional turntable type switching means. 6 is a cross-sectional view of the reflecting objective, FIG. 6 is a plan view showing the conventional turntable type switching means in FIG. 5, and FIG. 7 is a plan view similar to FIG. 8 is a plan view showing a conventional sliding type switching means.

  In the figure, reference numeral 1 denotes a reflection objective mirror of the total reflection absorption spectrum measuring apparatus according to the present invention. The objective mirror includes a concave primary mirror 2 having a hole in the center, and a convex secondary axis coaxial with the concave primary mirror 2. It is composed of a mirror 3 and a hemispherical ATR prism 4. The concave primary mirror 2, the convex secondary mirror 3 and the ATR prism 4 are arranged on the same optical axis as the measurement light 5 emitted from a spectroscope or interferometer (not shown), and the center of curvature of the ATR prism 4 is mainly concave. It arrange | positions so that it may be located in the condensing point P of the mirror 2. FIG. The sample S is placed on the sample stage 19 in contact with the lower surface of the ATR prism 4.

  The ATR prism 4 is held by a holder 7 fixed to the rotating shaft 6. The rotating shaft 6 is held by a frame 8 of the reflecting objective 1 so that it can rotate around a horizontal line on the sample surface, and a knob 9 for manually rotating is provided at one end exposed to the outside. It has been. The central portion of the holder 7 is formed eccentrically with respect to the rotational axis of the rotary shaft 6, and the ATR prism 4 is attached to the eccentric portion. Thus, the rotary shaft 6 can be rotated 180 ° from the sample measurement position in FIGS. 1 and 2 to the retracted position in FIG. 3 by operating the knob 9. Further, a positioning mechanism 10 is provided so that the ATR prism can be temporarily held in a stable posture at the sample measurement position and the retracted position, respectively. The positioning mechanism 10 may be of any type as long as it can maintain the posture, but in this embodiment, the concave portions 10a and 10a provided at symmetrical positions on the peripheral surface of the rotary shaft 6 and the concave portions The latch 10b is selectively elastically fitted.

  Further, when the ATR prism 4 is in the retracted position of FIG. 3, a hole 11 that allows the measurement light to pass therethrough is formed in the holder 7. The hole 11 is preferably made as large as possible as the holder strength permits. For example, as shown in FIG. 4, it is preferable to form two large holes symmetrically. The hole 11 can also be formed of a light transmissive material such as transparent glass.

When performing ATR measurement with this total reflection absorption spectrum measuring apparatus, the knob 9 is operated to place the ATR prism 4 at the measurement position shown in FIGS. In a state where the sample S is placed in contact with the lower surface of the ATR prism 4, measurement light is emitted from a spectroscope or interferometer (not shown). For example, the right half of the optical axis in FIG. 1 is incident on the lower objective mirror optical system, and the light is reflected by the convex secondary mirror 3 and the concave primary mirror 2 and is collected at the focal point P of the objective optical system. The The measurement light focused on the point P is not bent by the ATR prism 4 but is collected at the point P as it is, is totally reflected by the sample surface, and goes up the left half of the optical axis of the objective optical system and is detected.
When visual observation is performed, the knob 9 is operated to rotate the rotary shaft 6 by 180 ° from the sample measurement position shown in FIGS. 1 and 2 to the retracted position shown in FIG. At this position, the measurement light is incident on the condensing point from the hole 11, so that the function as a reflection objective mirror is not impaired.

  The present invention is not limited to the embodiment described above, and can be implemented with appropriate modifications within the scope of the constituent features of the present invention and exhibiting the effects described above. For example, switching between the ATR measurement mode and the visible observation mode can be performed by an electric button operation instead of a manual operation by a knob.

  The total reflection absorption spectrum measuring apparatus of the present invention is applied as a measuring apparatus used for qualitative analysis and fixed analysis of various substances including organic substances such as polymer materials.

Sectional drawing of the reflective objective mirror of the total reflection absorption spectrum measuring device which is one Embodiment of this invention. The expanded sectional view of the ATR prism part of the said reflective objective mirror. FIG. 3 is a cross-sectional view similar to FIG. 2 showing a state where the ATR prism is reversed and moved to the retracted position. FIG. 4 is an enlarged perspective view of an ATR prism portion when it is reversed and moved to a retracted position. Sectional drawing of the reflective objective mirror provided with the conventional turntable type switching means. The top view which shows the conventional turntable type switching means in FIG. The top view similar to FIG. 6 which shows the state at the time of visible observation. The top view which shows the slide-type conventional switching means.

Explanation of symbols

1: Reflective objective mirror 2: Concave primary mirror 3: Convex secondary mirror 4: ATR prism 5: Measuring light 6: Rotating shaft 7: Holder 10: Positioning mechanism 11: Light transmitting means (hole)

Claims (3)

  In a total reflection absorption spectrum measuring apparatus comprising a reflection objective optical system composed of a concave primary mirror and a convex secondary mirror and an ATR prism having a total reflection surface at a condensing point of the optical system, a holder for holding the ATR prism is rotated. The rotating shaft is formed to rotate around a horizontal line on the sample surface placed on the lower surface of the ATR prism. By rotating the rotating shaft, the ATR prism is moved upward from the sample measurement position. The total reflection absorption spectrum measuring apparatus is configured such that the light transmitting means is formed on the holder so as to allow the measurement light to pass when the ATR prism is in the retracted position.   The total reflection absorption spectrum measuring apparatus according to claim 1, wherein the ATR prism is attached at a position eccentric to a rotation axis of a rotation axis.   The total reflection absorption spectrum measuring apparatus according to claim 1, further comprising a positioning mechanism that temporarily holds the ATR prism at a sample measurement position and a retracted position.

Images