JPH07134264A - Display device - Google Patents

Abstract

PURPOSE:To miniaturize and simplify the entire part of a display device by constituting the device in such a manner that a relay lens system is made approximately telecentric to the display means side. CONSTITUTION:The luminous flux La based on the image information displayed on a display means 11 is condensed by a relay lens system 12 and the aerial image of the image information is formed in an intermediate imaging position 13. The luminous flux La is thereafter made incident on a condenser mirror 15 via a beam splitter 14 arranged in front of an observer. The luminous flux La is then reflected by the condenser mirror 15, is transmitted through the beam splitter 14 and is guided to an eye point 15, there by, the aerial image formed in the intermediate imaging position 13 is observed. The relay lens system 12 is made telecentric to the display means side. As a result, the good observation of the image is possible even if a spatial optical modulation element having the directivity of an exit characteristic strong in a perpendicular direction is used as the display means 11. The relay lens system is effectively made telecentric to the display means 11 side by arranging a field lens on the display means 11 side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device, and more particularly to observing image information of a display means arranged in the vicinity of an observer's eye as a magnified virtual image through a beam splitter, such as a helmet mount display or head mounted display. The present invention relates to a display device suitable for a display or the like.

[0002]

2. Description of the Related Art Conventionally, a so-called helmet mount display (hereinafter referred to as HMD) integrally formed with a helmet has been used as a display device arranged near an eye of an observer, and is a high-performance aircraft pilot. It is used as a display device for displays and simulations.

For example, Japanese Laid-Open Patent Publication No. 3-39924 proposes an HMD for displaying various flight data on a pilot in an overlapping manner with an outside scene.

In the publication, a light flux from image information displayed on a display means is condensed by a relay lens system to form an aerial image of the image information, and the aerial image is a catadioptric having a beam splitter and a coupler. The eyepiece means guides the light beam to the observer's eye, and transmits the light flux from the outside scene to the observer's eye through the coupler and the beam splitter. Thereby, the image information displayed on the display means and the image information of the outside scene are observed in the same visual field.

Also, Optical Approaches to the Helmet
Mounted Display (SPIE vol1116 1989) also discloses a display device having a similar configuration.

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the display device proposed in Japanese Patent No. 24, a CRT is used for displaying image information, which makes it difficult to downsize the entire device.

A liquid crystal display device (hereinafter referred to as L
In general, an LCD has a stronger directivity of emission angle characteristics in the vertical direction than a CRT, and a light beam with a large emission angle causes vignetting on the LCD surface. Therefore, a light beam based on some image information is used. Can no longer guide light to the observer's eyes.

Further, since the contrast decreases as the light beam based on the emission angle deviated from the vertical direction of the LCD surface, in order to observe the image information satisfactorily, the emission angle of the light beam center from the LCD in the off-axis light beam of the relay optical system. It is necessary to dispose an optical system in consideration of the NA of the light flux.

Further, in the conventional HMD, no consideration has been given to the observation with the observer wearing glasses. Conventionally, when an observer requiring diopter adjustment observes image information on the display means, it is necessary to provide the optical system with the diopter adjuster.

Further, when image information is superimposed on an outside scene for observation, it is necessary to provide a diopter adjusting means even for a light flux from the outside scene, which increases the number of optical system parts and reduces the size and simplification of the entire apparatus. There was a problem of hindering.

Therefore, it is desirable that an observer who needs spectacles can observe with the spectacles worn. However, in general, the distance (eye point length) between the optical system and the observer's pupil is short, and it is very difficult to secure an eye point length for observing while wearing glasses.

The present invention facilitates miniaturization of the entire apparatus by appropriately configuring each element such as the display means, the relay lens, and the half mirror, and enables good observation of the image information displayed on the display means. The purpose is to provide a display device that can be used.

[0013]

According to the display device of the present invention, a light flux based on image information displayed on the display means is condensed by a relay lens system to form an aerial image of the image information, and the light flux is observed by an observer. In the display device, which is incident on a condenser mirror through a beam splitter disposed in front, is reflected by the condenser mirror, is guided to the observer's eye through the beam splitter, and observes the aerial image, the relay The lens system is characterized in that it is substantially telecentric on the display means side.

Further, a light beam based on the image information displayed on the display means is condensed by a relay lens system to form an aerial image of the image information, and at least a part of the light beam is arranged in front of an observer. Reflected by, and made incident on a condenser mirror arranged in front of the beam splitter, and reflected by the condenser mirror at least a part of the luminous flux and transmitted through the beam splitter. In a display device that guides light to the eye to observe the aerial image, the relay lens system is substantially telecentric to the display means side.

In particular, the diagonal screen dimension of the display means is h,
When the lateral magnification of the relay optical system is β and the focal length of the condenser mirror is fm, 20.0 <h · β <40.0 (1) 35.0 <fm <50. It is characterized by satisfying 0 (2).

Further, the display means is a light transmission type liquid crystal display element, a light reflection type liquid crystal display element, an element whose fine mirrors are arranged in a lattice and whose angle can be controlled for each fine mirror, and the like. There is.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic view of the essential parts of a first embodiment of the present invention.
2 is a perspective view of a main part when two display devices of this embodiment are arranged near the left and right eyes of an observer, respectively. 2 to 5 are cross-sectional views of optical systems of Numerical Examples 1 to 4 described later, and FIGS.
FIG. 9 is a diagram of various aberrations of Numerical Examples 1 to 4 described later. 6 to 9, the vertical axis length of spherical aberration is the pupil height above the eye point, and the vertical axis lengths of astigmatism and distortion are each half the diagonal length on the display means 11. Shows the length of. In addition, various aberrations are aberration diagrams of the entire optical system (lens system from the cover glass to the half mirror) when the object point is the display unit 11.

In FIG. 1, 11 is a display means having a spatial modulation element such as LCD, 12 is a relay lens system for forming image information on the display means 11 on an intermediate image forming surface 13, and the display means It is telecentric on the 12th side.

Reference numeral 14 is a beam splitter such as a half mirror having a reflecting and transmitting action. A condenser mirror 15 is composed of a spherical mirror, an aspherical mirror or the like, and guides the light flux from the aerial image on the intermediate image forming surface 13 to the eyepoint 16.

In this embodiment, the light beam La based on the image information displayed on the display means 11 is condensed by the relay lens system 12 to form an aerial image of the image information at the intermediate image forming position 13. After that, the light beam La is made incident on the condensing mirror 15 via the beam splitter 14 arranged in front of the observer, and the light beam La is reflected by the condensing mirror 15 and transmitted through the beam splitter 14 to the eye point 16. The light is guided so that the aerial image formed at the intermediate image forming position 13 is observed.

Here, the observer observes the aerial image from the eyepoint 16 in the plus y direction as shown in FIGS.

Although FIG. 1 shows the case where the condensing mirror 15 is a total reflection type condensing mirror having no translucency and only the image information of the display means 11 is observed, the condensing mirror 15 has translucency. It is also possible to superimpose the image information of the outside scene using a mirror and observe both image information simultaneously in the same field of view.

In this embodiment, the relay lens system 12 is telecentric on the display means 11 side. As a result, as the display means 11, a spatial light modulator having a strong directivity of emission characteristics in the vertical direction, for example, a light transmission type liquid crystal element, a light reflection type liquid crystal element, and micromirrors are arranged in a grid pattern and an angle is set for each micromirror. Even if a controllable element or the like is used, the image information can be satisfactorily observed, and the miniaturization of the entire apparatus is facilitated.

Next, a telecentric relay lens system 1
A technical explanation of No. 2 will be given. Relay lens system 12
In order to make the display means 11 side telecentric, it is effective to dispose a field lens on the display means 11 side.

FIG. 13 is an explanatory view showing an expanded optical system when a field lens is used. In the figure, 131 is image information on the display means, and 132 is a field lens. Reference numeral 12 is a relay lens system having the field lens 132 and the lens 133, and forms image information 131 on the intermediate image forming surface 13.

Reference numeral 134 is the stop position of the relay lens system 133, and 136 is the principal ray of the off-axis light beam from the display means.

Of the off-axis light flux based on the image information 131, for example, the chief ray 136 enters the field lens 132 so as to be parallel to the optical axis, intersects the optical axis at the diaphragm position 134, and forms an image on the intermediate image forming surface 13. To do. Telecentric is set by setting this to hold in the entire off-axis range.

Next, a setting method for making the relay lens system 12 telecentric in FIG. 1 will be described.

First, when the angle of view, diopter and paraxial focal length of the converging mirror are determined by the observer, on the intermediate image plane 13 by the relay lens system 12 based on the paraxial image formation relationship of the eyepiece system. Image size and the exit angle of the off-axis ray from the aerial image to the condenser mirror 15, which is the eyepiece. That is, the exit pupil position and the exit angle of the relay lens system 12 with respect to the intermediate image plane 13 are determined.

Further, if the incident angle of the lens 133 is determined within a range in which various aberrations can be corrected with respect to this outgoing angle, the lens 13
The entrance pupil position of 3 is determined. Therefore, if the focal length of the field lens 132 is set to be the distance from the rear principal point position of the field lens 132 to the entrance pupil position of the lens 133, various aberrations are corrected well and the display means is telecentric. be able to.

Next, the technical meaning of each conditional expression will be described.
Conditional expression (1) relates to the product of the diagonal screen size of the display means 11 and the lateral magnification of the relay lens system 12, and represents the diagonal size of the aerial image formed by the relay lens system 12. If the upper limit of conditional expression (1) is exceeded, it will be difficult to obtain a long eyepoint length while maintaining a wide angle of view. Less than,
This will be described with reference to the drawings.

FIG. 10 is a schematic view of the essential parts showing the arrangement of each element when the upper limit of conditional expression (1) is exceeded. 10 in the figure
1 is an aerial image by a relay lens system (not shown), 102 is a condenser mirror, 103 is a beam splitter, and 104 is an eye point.

In the figure, the case where the respective elements are symmetrically arranged for the left and right eyes is shown. Here, the base line length d is determined according to the observer, and when the angle of view 2ω is determined, the eyepoint 1 is set in order to avoid physical interference between the symmetrically arranged elements.
The maximum distance Lmax from 04 to the spherical mirror 102 is determined. Here, the horizontal length a of the aerial image 101, FIG.
The following expression holds for the inclination θ of the surface on which the aerial image 101 is formed with respect to the optical axis of the condenser mirror 102 at 0 and the eyepoint length e.

E <Lmax−a · cos θ From this, when the conditional expression (1) is exceeded, the length a in the above expression becomes an excessive value, and an eyepoint length that allows observation while wearing glasses can be obtained. It will be difficult.

If the lower limit is exceeded, the relay lens system blocks the light beam from the condenser mirror to the eye point, which is not preferable. Hereinafter, description will be given with reference to the drawings.

FIG. 11 is a diagram showing the arrangement of the optical system when the lower limit of conditional expression (1) is exceeded. 111 is a relay lens system, 112 is an aerial image located on the image plane of the relay lens system 111, 113 is a condenser mirror, 114 is a beam splitter, and 115 is an eye point.

When the aerial image 112 is made smaller, the exit pupil position of the relay lens system 111 approaches the position of the aerial image 112.
If the relay lens system 111 is configured as a rear diaphragm, the movement of the entire relay lens system 111 can be avoided, but it cannot cope with a large movement of the exit pupil.

Therefore, when the relay lens system 111 approaches the aerial image 112 with the movement of the exit pupil and the lower limit of conditional expression (1) is exceeded, the reflected light beam from the half mirror 114 or the condenser mirror 113 is blocked and a part of the image is vignetted. Is not good because it occurs.

Conditional expression (2) relates to the focal length of the condenser mirror which is an eyepiece. If the upper limit of conditional expression (2) is exceeded, the optical path length from the aerial image on the intermediate image plane to the condenser mirror becomes long, making it difficult to downsize the entire apparatus. On the other hand, if the lower limit of conditional expression (2) is exceeded, the curvature of field generated by the condenser mirror becomes excessive and it becomes difficult to correct it by the relay lens system.

The beam splitters 103 and 114 need only have the functions of reflection and transmission, and a polarization beam splitter or the like may be used.

According to the present embodiment, by appropriately configuring each element as described above, various aberrations of the optical system can be satisfactorily corrected at a magnification of about 37 times and an angle of view of about 37 ° while reducing the size of the entire apparatus. A display device can be obtained.

Further, since the eyepoint length is set to be sufficiently long so that the observer can observe while wearing the glasses, the entire apparatus can be made compact and simple.

Next, numerical examples 1 to 4 of the present invention will be shown. In Numerical Examples 1 to 4, Ri is the object side (display means side)
The radius of curvature of the i-th optical element, D
i is the i-th lens thickness or air gap, and Ni and νi are the refractive index and Abbe number of the i-th optical element, respectively. Table 1 shows the relationship between the above-mentioned conditional expressions and various numerical values in the numerical examples.

[0044]

[Table 1] Numerical Example 1 Ri Di Ni νi ∞ 0.00 1 Display Surface 1 ∞ 1.00 1.51633 64.15 Cover Glass 2 ∞ 9.40 1 3 ∞ 3.00 1.51633 64.15 Field Length 4 -37.841 14.40 1 5 34.152 5.00 1.69680 55.53 6 1 -36.491 188 4.20 1.83481 42.72 8 56.663 1.00 1 9 -96.058 1.40 1.84666 23.78 10 9.570 9.60 1 11 911.007 1.10 1.69895 30.12 12 22.434 4.40 1.79952 42.24 13 -20.511 47.20 1 14 ∞ 30.00 1 Half mirror (reflection) 15 81.40 160.00 10.00 1.51633 64.15 Half mirror (transmissive) 17 40.00 1 18 Eye point Object height (diagonal) 17.8 mm Angle of view (2ω) 37 ° Relay system lateral magnification 1.6 Diopter -1 dpt (Numerical example 2) Ri Di Ni νi ∞ 0.00 1 Display surface 1 ∞ 1.00 1.51633 64.15 Cover glass 2 ∞ 4.00 1 3 ∞ 3.00 1.51633 64.15 Field length 4 -40.000 31.11 1 5 35.187 4.20 1.6 9680 55.53 6 -56.425 0.25 1 7 19.025 4.30 1.83481 42.72 8 -81.546 1.00 1 9 -36.376 1.40 1.80518 25.43 10 13.455 8.11 1 11 -64.926 4.40 1.80400 46.58 12 -22.318 72.49 1 13 13 ∞ 30.00 1 half mirror (reflection) 14 92 1 Spherical mirror 15 ∞ 4.00 1.51633 64.15 Half mirror (transmission) 16 40.00 1 17 Eye point Object height (diagonal) 17.8 mm Field angle (2ω) 37 ° Relay system lateral magnification 1.8 Diopter -1 dpt (Numerical example) 3) Ri Di Ni νi ∞ 0.00 1 Display surface 1 ∞ 1.00 1.51633 64.15 Cover glass 2 ∞ 4.00 1 3 ∞ 5.00 1.60311 60.70 Field length 4 -55.000 61.20 1 5 49.107 3.20 1.69680 55.53 6 -70.402 0.25 1 -204.384 1.00 1 9 -53.742 1.40 1.80518 25.43 10 14.009 11.70 1 11 -40.148 3.40 1.80400 46.58 12 -19.349 63.84 1 13 ∞ 30.00 1 Half mirror (reflection) 14 92.360 30.00 1 Spherical mirror Ra 15 ∞ 4.00 1.51633 64.15 Half mirror (transmission) 16 40.00 1 17 Eye point Height (diagonal) 35.6 mm Angle of view (2ω) 37 ° Lateral magnification of relay system 0.9 Diopter -1 dpt (Numerical example 4) Ri Di Ni νi ∞ 0.00 1 Display Surface 1 ∞ 1.00 1.51633 64.15 Cover Glass 2 ∞ 4.00 1 3 ∞ 5.00 1.60311 60.70 Field Length 4 -60.000 64.94 1 5 111.874 3.20 1.69680 55.53 6 -51.084 42.208. 1.00 1 9 -40.803 1.40 1.80518 25.43 10 16.128 7.03 1 11 -35.187 3.40 1.80400 46.58 12 -17.329 55.98 1 13 ∞ 30.00 1 half mirror (reflection) 14 81.680 30.00 1 spherical mirror 15 ∞ 4.00 1.51633 64.15 half mirror (transmission) 16 40.00 1 17 Eye point Height (diagonal) 35.6mm Angle of view (2ω) 37 ° Lateral magnification of relay system 0.8 Diopter -1dpt

[0045]

According to the present invention, by appropriately configuring each element as described above, it becomes easy to downsize the entire apparatus,
A display device capable of observing image information well can be achieved.

[Brief description of drawings]

FIG. 1 is a schematic view of an essential part of Embodiment 1 of the present invention.

FIG. 2 is a sectional view of an optical system according to Numerical Example 1 of the present invention.

FIG. 3 is a sectional view of an optical system according to Numerical Example 2 of the present invention.

FIG. 4 is a sectional view of an optical system according to Numerical Example 3 of the present invention.

FIG. 5 is a sectional view of an optical system according to Numerical Example 4 of the present invention.

FIG. 6 is a diagram showing various types of aberration in Numerical Example 1 of the present invention.

FIG. 7 is a diagram of various types of aberration in Numerical example 2 of the present invention.

FIG. 8 is a diagram showing various types of aberration in Numerical Example 3 of the present invention.

FIG. 9 is a diagram showing various types of aberration in Numerical Example 4 of the present invention.

FIG. 10 is an explanatory diagram of a part of the display device of the present invention.

FIG. 11 is an explanatory diagram of a part of the display device of the present invention.

FIG. 12 is a perspective view of a main part when the display device of the present invention is arranged near an observer's eye.

FIG. 13 is an explanatory diagram of a part of the optical system of the present invention.

[Explanation of symbols]

 11 display means 12 relay lens system 13 intermediate image plane 14 beam splitter 15 condenser mirror 16 eyepoint

Claims (6)

[Claims] 1. A light flux based on image information displayed on a display means is condensed by a relay lens system to form an aerial image of the image information, and the light flux is collected through a beam splitter arranged in front of an observer. In a display device which is incident on an optical mirror, is reflected by the converging mirror, is guided to the observer's eye through the beam splitter, and observes the aerial image, the display means is a spatial light modulator. A display device characterized in that the relay lens system is substantially telecentric on the display means side. 2. A beam splitter in which a light flux based on image information displayed on a display means is condensed by a relay lens system to form an aerial image of the image information, and at least a part of the light flux is arranged in front of an observer. Reflected by, and made incident on a condenser mirror arranged in front of the beam splitter, and reflected by the condenser mirror at least a part of the luminous flux and transmitted through the beam splitter. In a display device that guides light to the eye to observe the aerial image,
The display device is characterized in that the display means is a spatial light modulator, and the relay lens system is substantially telecentric on the display means side. 3. When the diagonal screen size of the display means is h, the lateral magnification of the relay optical system is β, and the focal length of the condenser mirror is fm, 20.0 <h · β <40.0. The display device according to claim 1, wherein 35.0 <fm <50.0 is satisfied. 4. The display device according to claim 1, wherein the display means is a light transmission type liquid crystal display element. 5. The display device according to claim 1, wherein the display means is a light reflection type liquid crystal display element. 6. The display device according to claim 1, wherein the display means is an element in which micro mirrors are arranged in a lattice and the angle of each micro mirror can be controlled.