CN102928980B - The binary optical system of respirator Helmet Mounted Display - Google Patents

Abstract

The invention discloses a kind of binary optical system of respirator Helmet Mounted Display, it is characterized in that: adopt a toroidal reflectors and relay system composition, catoptron has toroid, and light sends from miniature display screen, successively through relay system, catoptron, finally carry out human eye pupil place.The invention has the advantages that: system bulk is little, lightweight, because the inclination angle of the mechanical axis of catoptron and the chief ray of zero visual field is zero, and reflecting surface plating Narrowband Spectral High-Reflectivity Filter Multilayers, binary channels display can be realized, show owing to adopting binary channels mode, the stop of whole Helmet Mounted Display to the visual field is minimum, and when watching, human eye can not need deflection angle, improves comfortableness.<!--1-->

Description

The binary optical system of respirator Helmet Mounted Display

Technical field

The present invention relates to optical system, specifically a kind of optical system of Helmet Mounted Display.

Background technology

Helmet Mounted Display (HeadMountedDisplay) is called for short HMD and is divided into half throwing type and full throwing type, the image that small two-dimension display produces can amplify via optical system by it, collimated image is shown to infinite distance or place enough far away, becomes the effect screen of outside several meters tens of meters.Because head-wearing display device is arranged on the head of observer, therefore it must compact and lightweight, to alleviate the load of observer.Along with observing the increase of visual field, range of observation also can increase, and observer could the dynamic image of more absorbed observation high-quality.For head-mounted display system, Large visual angle is also considerable.The visual field of optical system, exit pupil diameter are the relation of restriction mutually between focal length three, reach Large visual angle, large exit pupil diameter and short focus quite difficult simultaneously.

Nineteen sixty-eight in the world first Helmet Mounted Display be truly military helmet display, namely U.S. ARPA Information Processing Technology Office director IvanSutherland develop " sword of Damocles " Helmet Mounted Display.Originally be mainly opportunity of combat and battlebus driver outfit; and now; no matter be fighter plane, the helmet worn of helicopter or individual soldier is not singly protective device; several functions condenses upon in the helmet by the science and technology of develop rapidly; becoming the competent assistant helping the equipment such as user operating aircraft, aiming, acquisition cartographic information, is the important tie between user and its weapon, base.In addition, the status of civilian Helmet Mounted Display in virtual technology application system is also very important.Because display system is mounted on the helmet, therefore to weight and volume requirement very high, in addition if individual soldier uses, then stricter requirement is proposed to reliability.Although GB and national military standard do not have definite requirement to the emergent pupil distance of optical system; but the 3.2.3.4 of " GJB_1323-1991_ optical observation instrument general specification " points out: according to purposes determination distance of exit pupil or the clear eye distance of product; protection operating personnel eyes are not wounded, and also can observe when putting on respirator.

Helmet Mounted Display (HMD) is as portable display, and it can make staff be liberated.On-the-spot at the core biochemistry (NBC) of danger, soldier or engineering staff will carry professional equipment, maintenance tool, weapon usually, or will bear the wounded, or need climbing etc., and the frequent and external world carries out video communication again, the now liberation of both hands has very large meaning.In addition, the environment at NBC scene is more severe, complicated, and usually also along with dense smoke, thick fog, the sight line of staff is hindered, and brings difficulty to maintenance job and search-and-rescue work.If be equipped with thermal imaging system, the first-class imaging device of night vision camera to HMD, greatly can improve the work efficiency of staff, reduce its hazard level.

Be published in " IFAWC2006, MobileResearchCenter, TZIUniversityBremen.Germany " article " HeadMountedDisplayforFireFighters " (display that fireman wears) on (Bremen, Germany university Olds moves research centre IFAWC2006), for the HMD system designed for fireman, also relates to the HMD system of NBC operator, this HMD throws formula entirely, and it only has single channel, can not watch external information simultaneously.And it is in order to reduce block vision, a lot, human eye needs when watching to rotate very wide-angle for the zero visual field chief ray of HMD and human eye straight ahead gaze direction deflection angle, and long-time viewing meeting is very tired.

Summary of the invention

The technical problem to be solved in the present invention is exactly the deficiency for present technology, and provide a kind of optical system of the Helmet Mounted Display based on respirator, it has binary channels, effectively can possess best man-machine efficacy by aberration correction raising picture element.

The present invention solves the problems of the technologies described above by the following technical solutions: the binary optical system of respirator Helmet Mounted Display of the present invention adopts a toroidal reflectors and relay system composition, catoptron has toroid, to the centre wavelength of miniature display screen, there is high reflectivity, the beam energy of other wavelength, to be transmitted as master, can reach twin-channel object like this.Because the free space of respirator is smaller, the catoptron of other designs is placed in position on the lower side, human eye straight ahead gaze direction, and catoptron of the present invention is placed in position on the lower side, human eye straight ahead gaze direction, and relay system and miniature display screen are placed in the side of the number of people.

Preferably, described catoptron is coated with Narrowband Spectral High-Reflectivity Filter Multilayers, to miniature display screen centre wavelength there is high reflectivity, the beam energy of other wavelength is to be transmitted as master.The light reflectance of described Narrowband Spectral High-Reflectivity Filter Multilayers to 494-544nm wave band is greater than 70%, and the transmitance of other visible light wave range is greater than 90%.

Preferred, the inclination angle of the mechanical axis of described catoptron and the chief ray of zero visual field is zero, to reach the object of optical axis of turning back.

Preferably, the miniature display screen in the present invention uses OLED miniature display screen, and emergent light is Single wavelength.

Preferably, described relay system is made up of four lens, at least two panels mechanical axis tilts and bias mutually, optimum, the mechanical axis of four lens tilts and bias mutually, with the off-axis aberration of compensatory reflex mirror, miniature display screen also needs to carry out Sloped rotating relative to optical axis, the mechanical axis of namely described miniature display screen and the angle of optical axis non-vanishing.

Have a slice to be gummed mirror in four lens of above-mentioned relay system, the object of gummed mirror is correct certain aberration.

Comprise successively in above-mentioned relay system: negative lens, the first positive lens, gummed mirror, and second positive lens, light enters negative lens after miniature display screen sends, and enter catoptron from the second positive lens, second positive lens is plane near the one side of catoptron, convenient encapsulation, negative lens, the first positive lens and gummed mirror are all that plane is as the plane of incidence.

Preferably, above-mentioned gummed mirror is made up of two kinds of different materials.

Light sends from miniature display screen, successively through relay system, catoptron, finally carries out human eye pupil place.The light sent out from miniature display screen, after relay system, forms an intermediary image, and this intermediary image has certain off-axis aberration because the bias of relay system tilts; Light enters catoptron, and the off-axis aberration that relay system produces and the off-axis aberration that produces of catoptron compensate mutually, becomes flat shape light, be intersected in human eye pupil place after the light of each visual field is collimated by catoptron.

When image planes are positioned at infinite distance, the angular resolution of Helmet Mounted Display is:

$\mathrm{\&theta;}=\min [\frac{2\mathrm{tg}\frac{\mathrm{\&omega;}}{2}}{m},\frac{2\mathrm{tg}\frac{v}{2}}{n}]$

In formula: ω, v are respectively vertical and the full filed angle of horizontal direction; M, n are the pixel count in the horizontal and vertical direction on the effective display surface of image source (square 4: 3) respectively.If the pixel count selecting image source horizontal and vertical direction is 800 × 600, pel spacing is 2.4 μm.Calculating angular resolution corresponding to system by above formula is 0.77mrad, close to the minimum resolution 0.5mrad of human eye.If the effective focal length of helmet display optical system is designed to 36.3mm, the spatial frequency of optical system that now angular resolution matches should reach 30lp/mm.

Then Optical System Design input is as shown in table 1:

Table 1 optical design inputs

Effective focal length	About 36.3mm
		Field angle	25°
Emergent pupil distance	40mm
		Exit pupil diameter	8mm
Wavelength	494 ~ 544nm, peak value 525mm
		Resolution	During 30 lp/ mm, each visual field is all greater than 0.3
Luminance non-uniformity	≤20%
		Distortion	≤5%

The invention has the advantages that:

1. owing to adopting toroidal catoptron, the bore of relay system can reduce greatly, and therefore system of the present invention has little, the lightweight advantage of volume.

2. the inclination angle due to the mechanical axis of catoptron and the chief ray of zero visual field is non-vanishing, and reflection plating Narrowband Spectral High-Reflectivity Filter Multilayers, binary channels display can be realized.

3., owing to adopting binary channels mode to show, the stop of whole Helmet Mounted Display to the visual field is minimum.

4., owing to adopting binary channels mode to show, during viewing, human eye can deflect too many angle, improves comfortableness.

Accompanying drawing explanation

Fig. 1 is optical system X-Y scheme of the present invention.

Fig. 2 is the MTF figure of optical system of the present invention.

Embodiment

The Helmet Mounted Display of existing respirator only has single channel, can not watch external information simultaneously.And it is in order to reduce block vision, a lot, human eye needs when watching to rotate very wide-angle for the zero visual field chief ray of HMD and human eye straight ahead gaze direction deflection angle, and long-time viewing meeting is very tired.

Fig. 1 is optical system X-Y scheme of the present invention, and light sends from OLED miniature display screen 41, successively through relay system 30, catoptron 20, finally carries out human eye pupil place.From the light of OLED miniature display screen 41 after relay system 30, form an intermediary image, this intermediary image has certain off-axis aberration because the bias of relay system 30 tilts; Light enters catoptron 20, and the off-axis aberration that relay system 30 produces and the off-axis aberration that produces of catoptron 20 compensate mutually, becomes flat shape light, be intersected in human eye pupil 10 place after the light of each visual field is collimated by catoptron 20.Comprise in relay system 30: eyeglass 31 is positive lens, and its one side near catoptron 20 is plane, convenient encapsulation; Eyeglass 32 is gummed mirror, is made up of two kinds of different materials; Eyeglass 33 is positive lens; Eyeglass 34 is negative lens, and its one side near OLED miniature display screen is plane, convenient encapsulation.

Be applied to the Small-scale Flat display of Helmet Mounted Display at present, include electroluminescent display (OLED) and liquid crystal display (LCD).Owing to needing backlight when liquid crystal display shows, and also need when subzero works to increase temperature control circuit, cause power consumption for displays and volume to increase, therefore the present embodiment selects OLED to be display screen, and its detail parameters is as table 2:

Table 2OLED shields parameter

Effective display area	12.8mm×9.6mm
		Resolution	852×600
Display brightness	1500cd/m 2
		Contrast	Be not less than 300:1
Gray shade scale	256
		Working temperature	-40℃～+65℃
Half spectral width	50nm(494nm-544nm)

Optics detail parameters is as shown in table 3:

Table 3 Optic structure parameter

Fig. 2 is the MTF figure of optical system of the present invention, and the MTF as seen from Figure 2 in each visual field all reaches more than 0.3 when 30lp/mm, meets design requirement.

The catoptron of optical system of the present invention is placed in position on the lower side, human eye straight ahead gaze direction, and relay system and miniature display screen are placed in the side of the number of people.

The foregoing is only the preferred embodiment of the invention; not in order to limit the invention; the any amendment done within all spirit in the invention and principle, equivalently to replace and improvement etc., within the protection domain that all should be included in the invention.

Claims (8)

1. the binary optical system of a respirator Helmet Mounted Display, it is characterized in that: adopt a toroidal reflectors and relay system composition, catoptron has toroid, and light sends from miniature display screen, successively through relay system, catoptron, finally carry out human eye pupil place;

Described catoptron is coated with Narrowband Spectral High-Reflectivity Filter Multilayers, to miniature display screen centre wavelength there is high reflectivity, the beam energy of other wavelength is to be transmitted as master;

The design input of described optical system is as follows:

Effective focal length: 36.3mm; Field angle: 25 °; Emergent pupil distance: 40mm; Exit pupil diameter: 8mm; Wavelength: 494 ~ 544nm; Resolution: during 30lp/mm, each visual field is all greater than 0.3; Luminance non-uniformity :≤20%; Distortion :≤5%.

2. the binary optical system of respirator Helmet Mounted Display as claimed in claim 1, is characterized in that: the inclination angle of the mechanical axis of described catoptron and the chief ray of zero visual field is zero.

3. the binary optical system of respirator Helmet Mounted Display as claimed in claim 1, is characterized in that: described miniature display screen uses OLED miniature display screen, and emergent light is Single wavelength.

4. the binary optical system of respirator Helmet Mounted Display as claimed in claim 1, is characterized in that: described relay system is made up of four lens, and at least two panels mechanical axis tilts and bias mutually.

5. the binary optical system of respirator Helmet Mounted Display as claimed in claim 4, is characterized in that: the mechanical axis of described four lens tilts and bias mutually, the mechanical axis of described miniature display screen and the angle of optical axis non-vanishing.

6. the binary optical system of the respirator Helmet Mounted Display as described in claim 4 or 5, is characterized in that: have a slice to be gummed mirror in four lens of described relay system.

7. the binary optical system of respirator Helmet Mounted Display as claimed in claim 6, it is characterized in that: comprise successively in described relay system: negative lens, the first positive lens, gummed mirror, and second positive lens, light enters negative lens after miniature display screen sends, and enter catoptron from the second positive lens, second positive lens is plane near the one side of catoptron, and negative lens, the first positive lens and gummed mirror are all that plane is as the plane of incidence.

8. the binary optical system of respirator Helmet Mounted Display as claimed in claim 6, is characterized in that: described gummed mirror is made up of two kinds of different materials.