JPH0519130B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical device, in particular to an optical device suitable for use in head-up display devices and so-called night vision goggles; Overhead display and night vision devices incorporating
Regarding goggles.

Currently available night vision goggles are generally unsuitable for use in the cabins of high performance aircraft, are bulky and unwieldy, and have inadequate optical performance.

It is an object of the present invention to provide an optical device suitable for constructing night vision goggles of a type suitable for use by pilots of high performance aircraft.

Briefly, the present invention is an optical device for a helmet-mounted head-up display or night vision goggle, which forms a real image of optical data to be displayed on a predetermined image plane. An optical device comprising an optical projector for projecting an image, and an element made of a light refractive material serving as an eyepiece for viewing the image by an observer, the element being approximately oriented relative to the image plane. a parallel first external input surface, a flat external output surface, a second external input surface parallel to the output surface, and a semi-transparent surface disposed between the output surface and the second external input surface; a semi-reflective internal surface, through which an observer receives an image of a scene in front of the observer through the parallel external output surface, a second external input surface, and a real image of optical data superimposed thereon; , an optical device adapted to be viewed through the eyepiece, wherein the parallel external output surface and the second external input surface of the eyepiece are inclined with respect to the first external input surface; the semi-transparent, semi-reflective internal surface is concavely curved toward the external output surface;
Thereby, a ray of light originating from the real image of optical data and entering the element from the first input surface,
refracted at the first input surface, fully internally reflected within the eyepiece toward the internal surface, reflected at the internal surface, and finally transmitted through the external output surface for viewing by the viewer. An optical device is provided.

The light beam is completely reflected inwardly at the external output surface, and the edge portion of the external output surface has an angle smaller than the critical angle of the refractive material of the element after entering the element from the first input surface. A fully reflective coating can be applied which causes rays from the real image that are incident on the external output surface at small angles to be reflected back to the internal surface.

Preferably, said internal surface is constituted by a tailored optical coating, such as a multilayer coating or a holographic coating.

The invention also provides an optical device for night vision goggles, wherein the optical projector creates on the image plane an enhanced image of a scene in front of the observer viewed through the eyepiece. An optical device is provided, characterized in that it is equipped with an image intensifying mirror.

Preferably, the optical projector comprises an objective lens and a roof prism between the image intensifier mirror and the scene in front of the viewer. In such a configuration, the objective lens and roof prism are arranged to refract the optical axis of the rays from the objective lens so as to direct the rays to the image intensifier.

In the following example, a binocular night vision goggle for an airplane pilot incorporating the optical device of the present invention is described.

In the first embodiment shown in FIGS. 1-8, goggles 11 are secured to a helmet 13 by means of a fitting 15. In the first embodiment shown in FIGS. The goggles 11 include an optical device 17a consisting of an optical projector 19a and an eyepiece 21a in the left eye position, and a similar optical device 17b provided in the right eye position.

The optical devices 17a and 17b are mounted on a housing 20 attached to the fixture 15. The eyepieces 21a and 21Bb are separated by a predetermined distance between the eyes.

The fixture 15 is a channel-shaped member, and both side flanges 23 thereof are tapered from the front to the rear and have outwardly bent ears 25. Flange 2
3 has a shape that almost matches the contour of the outer surface of the helmet 13, and the screw 2 passed through the ear piece 25
It is fixed to the helmet by 7.

The housing 20 is a lightweight housing, and includes 3
Two main chambers 31a, 31b, and 31c are defined. Two of them, 31a and 31b, are
Each accommodates the optical elements of optical projectors 19a and 19b. Chamber 31c houses the power supply for optical projectors 19a, 19b.

Specifically, each chamber 31a, 31b accommodates an image intensifying mirror 33a, 33b and a roof prism 35a, 35b, respectively. Front wall 3 of each room
Optical projector 19 is inserted into the threaded holes 7a and 37b.
Casings 41a and 41b housing objective lenses 39a and 39b of lenses a and 19b are screwed onto the casings 41a and 41b, respectively.

Each roof prism 35a, 35b is fixed to a bracket 43a (FIG. 6). Each bracket 43a is supported by a support stand 47a, 49a or 47b, 49 provided in the corresponding chamber 31a, 31b.
It has a web portion 45a that sits on top of the web portion 45a.
The prisms 35a and 35b are attached to a rubber mounting body 50a.
(FIG. 6) from the bracket. The bracket 43a is attached to each support stand 47.
a, 49a or 47b, 49b with screws 51 (FIG. 3).

The roof prisms 35a, 35b are located in the optical path at the intersection of the optical axes of the objective lenses 39a, 39b and the optical axes of the image intensifying mirrors 33a, 33b substantially perpendicular thereto.

The third chamber 31c is located between the chambers 31a and 31b, each having an image intensifying mirror 33, as mentioned above.
It accommodates power supplies 51a and 51b for power supplies 51a and 33b. The power supplies 51a and 51b are connected to the groove-shaped fixture 15.
It can be connected to a battery pack (not shown) by a conductor 52 extending therethrough.

The eyepieces 21a and 21b are collimating eyepieces. Each eyepiece, referring to eyepiece 21a of FIG. 4, consists of a two-part body made of a light-refractive material, such as glass or plastic, fitted within a frame 53a secured to housing 20. . Two parts 55a and 5 of each eyepiece 21a
A spherical, semi-transparent, semi-reflective interface 54a is interposed between the surfaces 7a. Eyepiece first part 5
5a has an input surface 59a and an output surface 63a. The input surface 59 is the output surface 61 of the image intensifying mirror 33a.
It lies in a plane approximately parallel to a. The output surface 63a is
It has a planar shape and is inclined at an acute angle with respect to the input surface 59a.

The second portion 57a of the eyepiece 21a is the portion 55a.
The input surface 67a has a planar shape parallel to the output surface 63a of the portion 55a.

The optical axes of the mirror surfaces formed by the interfaces 54a and 54b are parallel to the optical axes of the objective lenses 39a and 39b.

The goggles 11 are movable between a use position A and a non-use position B, as shown in FIG.
This movement is accomplished by pivoting the housing 20 about the threaded axis relative to the fitting 15. The goggles are attached to the protrusion 7 of the housing 20.
It is latched in the use position and the non-use position by a locking mechanism consisting of a short shaft 71 with a ball end attached to 3 and a leaf spring 75 whose one end is fixed to the fixture 15. That is, the ball of the short shaft 71 with a ball end is connected to the leaf spring 7 in the use position of the goggles 11.
5, and in the non-use position engages with the hole 79 of the leaf spring to hold the goggles.

The operation of each optical device 17 can be easily understood by referring to FIG. (In Figure 8,
The symbols a and b are removed from the reference numbers as follows:
This is to explain it as something common to a and b. )
As can be seen in FIG. 8, the light rays from the distant scene F in front of the observer wearing goggles are inverted by the objective lens 39, and after being refracted and inverted by the roof prism 35, It is directed to the image intensifier mirror 33 to form an intensified real image of the front scene on the output surface 61 of the image intensifier mirror. The rays from this real image are then transmitted to the input surface 5 of the first portion 55 of the eyepiece 21.
9 and undergoes refraction, then is completely reflected at its output surface 63, then reflected at a spherical semi-reflective interface 54 for collimation, and finally transmitted through the output surface 63 for observation. directed towards the person. Because the input surface 67 of the second portion 57 of the eyepiece 21 and the output surface 63 of the first portion 55 are parallel, the far scene F is viewed through the eyepiece 21 without distortion.

The optical devices 17a, 17b are designed such that light rays at a wide range of angles are refracted at the input surface 59 and exit from the output surface 63 over a large portion of the area of the real image at the output surface 61.

Reflection at the output surface 63 occurs when the light is incident at an angle equal to or greater than the critical angle of the material of the eyepiece 21; fully reflective coating on one or more edges;
It is also possible to reflect light rays incident on the edge of the surface 63 at an angle less than the critical angle.

The spherical reflective surface 54 may be formed by a conventional semi-transparent, semi-reflective coating, such as a multilayer coating or a holographic coating as described in GB 2971866. It can be formed by an optically tuned coating.

As a variant of the embodiment of FIGS. 1-8, means can be provided for introducing additional optical data into the field of view of the wearer of the goggles. One such variant embodiment is shown in FIG.
In this embodiment, one of the eyepieces of the goggles 11,
For example, a compound prism 36 functioning as a beam splitter is provided in the optical path to the eyepiece 21b. Prism 36 consists of a roof prism 35b similar to that previously described and an additional prism element 35c superimposed on the roof prism. The surface of the prism element 35c at the interface with the roof prism 35b has a shape complementary to the roof surface of the roof prism.

Upstream of the compound prism 36, a relay lens system 3 is provided.
8 will be provided. Light from a display device consisting of a cathode ray tube (CRT) 42 is deflected by a light refractive element such as a mirror 40, and the relay lens system 3
8 and enters the composite prism 36. The input surface of the image intensifying mirror 33b is connected to the relay lens 3.
8, so that a real image from the CRT display device is formed on the output surface of the image intensifier mirror 33b. CRT 42 may constitute the final element of a subsystem that includes a remotely mounted infrared or low light television sensor (not shown). The signal from this remote sensor is used to control bright up during the CRT's scanning operation, thereby
Forms an image of the actual front scene on the CRT screen. Here is an example of a display device.
I mentioned CRT, but for example, light emitting diode (LED)
Other types of imaging devices such as arrays can be used.

It may also be desirable to provide composite image data within the field of view of the goggles. As can be seen in FIG. 9, a reticle 44 can be provided for this purpose in the optical path to one of the eyepieces, for example eyepiece 21b. The reticle 44 may be comprised of a graticule disposed between the output surface of the image intensifier mirror 33b and the eyepiece 21b, and an associated illumination source 48, as shown. The illustrated graticule consists of a glass disc 46 engraved with composite data, such as crosshairs or other graduations as shown, but alternatively,
Graticule is a group of optical fibers (not shown)
One end of each fiber is illuminated by, for example, a light emitting diode (LED), and the other end is illuminated by an image intensifying mirror 33b.
It may be placed between the output surface of the eyepiece 21b and the eyepiece 21b. In the latter case, when several LEDs are energized, they create a pattern of optical volatile points that constitute the composite data at the remote end of the corresponding optical fiber, which is viewed through the eyepiece. Such composite data can be either on the front scene viewed directly through the eyepiece 21b or on the front scene reflected towards the viewer by the rear eyepiece 21b intensified by the image intensifier 33b. Superimposed onto the image of the scene.

The goggles of FIG. 9 are shown mounted on a helmet in FIGS. 10 and 11. The cathode ray tube 42 and its associated HV power supply are housed within a protective cover 68 that projects laterally. On/off switches 80 are provided for the image intensifiers 33a, 33b, and a lever 8 is provided for changing the focus of the objective lenses 9a, 39b.
1a and 81b are provided. In this goggle, the interocular distance of the eyepiece is adjusted by a knurled knob 82 with an adjustment screw located in the center of the goggle.
It can be adjusted by. Power supplies 83a, 83b for the image intensifier mirrors are housed to the left of optical projector 19a and to the right of optical projector 19b, respectively.

In the embodiment described above, each eyepiece 21 consists of two pieces 55, 57 of optically refractive material with semi-transparent, semi-reflective surfaces such that the interface 54 between the pieces is Although curved in a spherically concave manner (toward the output surface 63 in the embodiment described above), one or both of the two pieces 55, 57 may have an index of refraction to enhance optical performance. It can be a composite piece consisting of two or more different segments. With this configuration, chromatic aberration can be reduced or completely avoided.

The goggles of the present invention described above have the following advantages.

(a) The large distance between the eye and the eyepiece allows the wearer to see around the eyepiece and observe the instruments in the airplane's cockpit and other parts of the real scene. You can also wear regular glasses.

(b) Since the goggles are compact, pilots can easily operate while wearing the helmet and goggles.

(c) The goggle's reflective optics superimpose the enhanced landscape to provide a complete, unbroken, ambient light image. This is ideal for reading cockpit gauges.

(d) Since these goggles are of the binocular type, the optical mechanism is simplified and a three-dimensional screen is provided.

(e) Since each image intensifier mirror only needs to cover a relatively small angle (30° in the example described above),
Improves resolution.

(f) Dual optical system increases reliability and safety.

However, the goggles of the above embodiments cannot necessarily avoid drawbacks such as optical distortion, astigmatism, and coma. Means for reducing such drawbacks were not specifically explained in the above embodiments, but of course, optical elements such as prisms and lenses to reduce the above drawbacks may be included in the optical system of the goggles. can be added. For example, such additional optical elements may be placed between the viewing position (eye) of the observer and the face 63 of the eyepiece 21, or alternatively, in close proximity to the input face of the eyepiece 21, or They may be placed in both positions or elsewhere in the optical path of the system.

The invention can be applied not only to night vision goggles, but also to other display devices. For example, the optical device of the present invention may be used as a display for an overhead display system.
can be incorporated into the unit. In that case,
The optical projector may consist of a display surface, such as the screen of a cathode ray tube, and a sub-optical system for forming an image of the display provided on the display surface onto an image plane. Advantageously, this secondary optical system includes optical elements for correcting aberrations of the main optical system of the goggles, but as in the case of the night vision goggles of the embodiment described above, the visual field of the display unit is As a quasi-correcting element, a concave reflective surface 54 can be provided at the interface within the eyepiece of the unit.

[Brief explanation of drawings]

1 is a perspective view of goggles of the present invention worn on a pilot's helmet, FIG. 2 is a front view of the helmet and goggles of FIG. 1, and FIG. 3 is a plan view of the helmet and goggles of FIG. Figure 4 is the third
Fig. 5 is a partial sectional view taken along the line - of Fig. 3; Fig. 6 is a partial sectional view taken along the line - of Fig. 3;
The figure is a cross-sectional view of elements 35a and 43a of FIG.
Figure 7 is a partial perspective view seen in the direction of the arrow in Figure 4;
FIG. 8 is an exploded perspective view of each optical element of the goggle half, FIG. 9 is a schematic exploded perspective view of a goggle according to another embodiment of the invention, and FIG. 10 is a front view of a helmet supporting the goggles of FIG. Figure 11 is the first
FIG. 2 is a side view of the helmet and goggles of FIG. In the figure, 11 is goggles, 13 is helmet, 1
5 is a fixture, 17 is an optical device, 19 is an optical projector, 21 is an eyepiece, 33 is an image intensifier, 35 is a roof prism, 39 is an objective lens, 55 and 57 are two-component elements, and 54 is an interface.

Claims (1)

[Scope of Claims] 1. An optical device for a head up display or night vision goggles attached to a helmet, which includes optical data F to be displayed.
An optical device 17 consisting of an optical projector 19 for forming a real image of on a predetermined image plane, and elements made of a light refractive material serving as eyepieces 21a and 21b for viewing the image by an observer. The element has a first external input surface 59 substantially parallel to the image plane, a flat external output surface 63, a second external input surface 67 parallel to the output surface, and the output surface. a semi-transparent, semi-reflective internal surface 54 disposed between the parallel external output surface 63 and the parallel external input surface 63; In an optical device adapted to be able to be viewed through the eyepiece through a second external input surface 67 and the inner surface 54 superimposed with a real image of optical data F, the parallel external output surface of the eyepiece 63 and 2nd
The external input surface 67 is inclined with respect to the first external input surface 59, and the semi-transparent, semi-reflective internal surface 54 is concavely curved toward the external output surface. Thereby, a ray of light originating from the real image of the optical data F and entering the element from the first input surface 59 is refracted at the first input surface and is refracted within the eyepiece 21a, 21b. completely internally reflected towards surface 54, which
4, and is finally transmitted through an external output surface 63 to be seen by an observer. 2. The light beam is completely reflected inwardly at the external output surface 63, and the edge portion of the external output surface 63 is exposed to the refractive material of the element after entering the element from the first input surface 59. 2. An optical device according to claim 1, wherein the optical device is provided with a fully reflective coating that causes rays from the real image incident on the external output surface 63 at angles smaller than a critical angle to be reflected back to the internal surface 54. . 3. The inner surface 54 is constituted by a tailored optical coating.
The optical device according to item 1 or 2. 4. An optical device for night vision goggles, wherein the optical projector 19 creates on the image plane an enhanced image of the scene in front of the observer viewed through the eyepieces 21a, 21b. 4. The optical device according to claim 1, further comprising image intensifying mirrors 33a and 33b. 5 The optical projector 19 has objective lenses 39a, 39b and a roof prism 3 between the image intensifying mirrors 33a, 33b and the scene in front of the observer.
5a and 35b, and the objective lens 39
a, 39b and roof prisms 35a, 35b,
Image intensifying mirrors 33a and 33b
5. The optical device according to claim 4, wherein the optical device is arranged so as to refract the optical axis of the light beam so as to direct the light beam. 6 comprising means for introducing additional optical data into the field of view of the observer, said means consisting of a reticle 44 arranged between said image intensifier mirror 33b and a first input surface 59 of said element; An optical device according to claim 4 or 5. 7 includes means for introducing additional optical data into the field of view of the observer, the means comprising a display device 42 providing an image of the additional optical data;
and an optical system 36, 38, which projects a real image of the additional optical data onto the input surface of the image intensifying mirror 33b.
Claims 4 to 40 consist of
The optical device according to any one of Item 6. 8. The optical device according to claim 7, wherein the optical system includes a relay lens 38 and a prism element 35c. 9. The optical device according to claim 8, wherein the prism element 35c constitutes a composite prism 36 combined with the roof-type prism according to claim 5. 10. A device according to any one of claims 1 to 9, comprising a pair of optical devices supported on a helmet 13 by a common mounting member to constitute a binocular-type night vision goggle. optical equipment.