JPS63138223A - Optical device - Google Patents

Abstract

PURPOSE:To improve the resolution by providing at least two pieces of parallel plates having prescribed inclination and thickness, in an optical path, and rotating them at a prescribed speed, respectively. CONSTITUTION:When an explanation is made with regard to the case of two pieces of parallel plates, a coupling lens 1 couples incident infrared rays on a focal plane 3 through the parallel plates 2-1 and 2-2. The parallel plates 2-1, 2-2 are formed by Ge and allow infrared rays to transmit through, have thickness (d) and inclined at angles theta1, theta2, respectively, against an optical axis. When a rotating speed of the parallel plate 2-2 is set to four times of a rotating speed of the parallel plate 2-1, a formed image executes a scan of 4X4 at a pitch of an effective picture element interval l=35mum, and as for a detecting element in this case, 4L, namely, an interval of 140mum is enough, and a conventional picture element number can be set to four times. The foregoing explains the case of two pieces of parallel plates, and when (n) pieces of plates are provided, the number of picture elements can be increased to 4<n> times.

Description

[Detailed Description of the Invention] [Summary] In order to increase the number of scans of an infrared two-dimensional sensor and improve the resolution of the most imaged pixel, the present invention provides a plurality of parallel flat plates that rotate around the optical axis, and each The thickness of the parallel plates, the inclination with respect to the optical axis, and the rotation speed are different.

[Industrial application field]

The present invention relates to an optical device, particularly an optical device used in an infrared two-dimensional sensor.

In a two-dimensional infrared sensor that obtains a two-dimensional distribution of light and a two-dimensional image, increasing the number of pixels as a way to improve resolution significantly improves the image quality.

Therefore, in order to increase the number of pixels in order to improve image quality, this optical sensor must be made highly dense.
For this reason, fine processing is required to form pixels. Furthermore, when this optical sensor is of a hybrid type, the number of connecting members (bumps) increases and is difficult to manufacture, and furthermore, as the number of pixels increases, the amount of charge handled decreases, resulting in a decrease in performance.

Therefore, there is a need for an optical device that optically increases the number of scans.

[Conventional technology]

In order to increase the number of pixels of an infrared two-dimensional sensor, the optical device conventionally used has the structure shown in FIGS. 4 and 5. As shown in FIG. The parallel plate 20 is arranged with an inclination angle θ° to the optical axis of the imaging lens 1 and the focal plane 3, and the parallel plate 20 is configured to rotate about the optical axis.

The infrared rays transmitted through the parallel plate 20 produce a displacement ΔX determined by the environment in which the parallel plate is placed, for example, the refractive index of the atmosphere and germanium, and the thickness d of the parallel plate 20, and are directed to the focal plane 3 parallel to the optical axis. reach

When this parallel plate 20 is rotated around the optical axis, a locus with a radius of ΔX is drawn on the focal plane. The X and Y axes of the focal plane are each doubled, and the resulting number of pixels is four times 2X2 (
(See Japanese Patent Application No. 61-28222).

FIG. 5 shows a conventional vibrating optical device, in which a parallel plate 2
This is a type in which the parallel plate 20 is vibrated back and forth at an angle of θ° instead of rotating 0, and the number of pixels is four times the same as described above. However, this type is mechanically more complicated than that shown in FIG.

[Problem that the invention seeks to solve]

The resolution using conventional optical devices is four times higher, and there is a problem in that it cannot handle even higher resolutions.

The object of the present invention is to provide an optical device with higher resolution in view of the above-mentioned conventional situation.

[Means for solving problems]

In this invention, at least two parallel flat plates which are obliquely intersecting the imaging lens and the optical axis and rotate about the optical axis are provided, and each parallel plate is configured to have a different thickness, inclination angle, and rotation speed.

[Effect]

The infrared rays displaced by the first parallel plate are further displaced by the second parallel plate, making it possible to increase the number of pixels.

〔Example〕

FIG. 1 is a schematic diagram showing an embodiment of an optical device according to the present invention. That is, the imaging lens 1 images the incident infrared rays on the focal plane 3 via the parallel plates 2-1 and 2-2. The parallel plates 2-1 and 2-2 are made of germanium and transmit infrared rays. For example, the parallel plate 2-1 is formed with a thickness d and is inclined at an angle θI with respect to the optical axis.

The parallel plate 2-2 has a thickness d and is inclined at an angle θ2p14. FIG. 2 shows the displacement state when this parallel plate is tilted with respect to the optical axis. This Figure 2 shows the displacement in the atmosphere using germanium with a refractive index of 4 as a parallel plate. As shown in the figure, the inclination angle, that is, the incident angle of the parallel plate is 2
The amount of displacement changes approximately linearly up to about 0''.

For example, the inclination θ1 of the parallel plate 2-1 is 1.885°.
If the thickness d is 1ml1, the displacement Δx1 is 2
It becomes 4.7 μm. The inclination θ2 of the parallel plate 2-2 is 3.7
79.

If the thickness is 1mm, the displacement Δx2 is 49.5μ
It becomes l. This state is shown in Table 1.

Table 1 If the optical device is set in this state and the rotational speed of the parallel plate 2-2 is set to four times the rotational speed of the parallel plate 2-1, the image formation will be as follows.
The result is as shown in FIG. That is, effective pixel interval L=35
A 4×4 scan is performed with a pinch of μ..., and the detection elements at this time may be arranged at intervals of 4L, that is, 140 μm.

With the above configuration, the number of pixels can be quadrupled compared to the conventional one.

The above explanation has been made using two parallel plates, but if n pieces are provided, the number of pixels can be increased four times.

〔effect〕

As is clear from the above description, according to the present invention, the number of pixels can be increased with a simple configuration including a plurality of parallel flat plates, which is extremely effective in improving resolution.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing an embodiment of the optical device according to the present invention, Fig. 2 is a diagram showing the relationship between the inclination angle and displacement of a parallel plate, and Fig. 3 is for explaining the relationship between the pixel and the detection element of the present invention. FIG. 4 is a schematic diagram showing a conventional optical device, and FIG. 5 is a schematic diagram showing a conventional vibrating optical device. In the figure, 1 is an imaging lens, 2-1 and 2-2 are parallel plates, and 3 is a focal plane. Hands-on = 73 疋 裟 1- Cooking axis department Reigori 1st figure I rtIlle' → flat tf flat uq iiFfIH1't M stop tq mf
ir:lJ Figure 2 Figure 3 Conventional 3L ke device 9ne T Odeki Figure 4 2041 Gothic class Figure 5

Claims (1)

[Claims] In an optical device that includes an imaging lens (1) and a parallel plate (2) made of a transparent member that is oblique to the optical axis of the imaging lens and rotates about the optical axis, a predetermined inclination is provided. An optical device characterized in that at least two of the parallel flat plates (2-1 to 2-n) having a thickness of 1 are provided in an optical path, and each of the parallel plates rotates at a predetermined speed.