JP2001264680A - Image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an image display device with which image information is observed by excellent image quality in a wide observation visual field while making a whole device small, especially, thinning an ocular optical system part in an observer's visual line direction. SOLUTION: The device is provided with a first optical element which has a reflection display means, a light incident surface, a light incident/exit surface opposing to the display means and at least one surface Ra and which is filled with the same material inside and with a second optical element which has an incident surface for making light fluxes from the display means enter, a plurality of eccentric reflection surfaces for reflecting the light fluxes from the incident surface and having power and an exit surface for emitting the light fluxes reflected from the reflection surfaces and for guiding a light to the pupil of an observer and which is filled with a same material inside. The one surface Ra of the first optical element is joined with a part of the incident surface of the second optical element and the light fluxes are reflected from a part of the joined surface and emitted from the incident/exit surface so that the display means is illuminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device, and more particularly, to an image display device, such as a reflection type liquid crystal device, which enlarges an image via an optical element having a free-form surface on which image information based on a light beam modulated light is appropriately set. The present invention relates to an image display device suitable for a head-mounted display (HMD), a glasses-type display, and the like, which are observed by viewing.

[0002]

2. Description of the Related Art Conventionally, a head-mounted type using an image display element (display element) such as a CRT or an LCD and enlarging and observing an image based on these display elements via an image observation optical system. An image display device (head-mounted display HMD) is well known.

FIG. 14 is a schematic view of a main part of an image display apparatus using a conventional coaxial concave mirror. In the figure, the light flux from the image information displayed on the display element 61 is reflected by the half mirror 62 and is incident on the concave mirror 63. The light beam reflected by the concave mirror 63 is guided to the observer E via the half mirror 62. The image information displayed on the display element 61 is
Is formed as an enlarged virtual image. This allows
The observer observes an enlarged virtual image of the image information displayed on the display element 61.

Further, for example, JP-A-7-333551, JP-A-8-50256, JP-A-8-160340, JP-A-8-17
No. 9238 proposes an image display device which uses an LCD (liquid crystal) as a display means for displaying image information and a thin prism as an observation optical system to reduce the thickness of the entire device.

FIG. 15 is a schematic view of a main part of an image display device proposed in Japanese Patent Application Laid-Open No. 7-333551. In FIG. 15, light emitted from the LCD 51 is
Are incident on the incident surface 53. Then, the light beam is folded between the total reflection surface 54 having the curvature formed on the small prism 52 and the reflection surface 55, and then the small prism 52 is emitted from the surface 54 to guide the light to the observer E. .
Thereby, a virtual image of the image information based on the display means (LCD) 51 is formed, and the observer E observes the virtual image. The reflection surface 55 of the small prism 52 is formed of an eccentric free-form surface constituted by an eccentric non-rotationally symmetric surface (a surface having a different optical power depending on the azimuth angle, a so-called free-form surface).

The type of optical system shown in FIG. 15 is characterized in that it is easier to make the entire apparatus thinner and to increase the angle of view of the observation field as compared with the conventional type using a coaxial concave mirror shown in FIG. are doing.

In an image display device such as a thin head mounted display (HMD) of the type shown in FIG. 15, it is attempted to use a reflective display device having a high aperture efficiency and advantageous for miniaturization as a display device. For example, as shown in FIG. 16, it is necessary to insert an illumination system 70 for illuminating the display element 51 between the display element 51 and the entrance surface 53 of the small prism 52.

Here, the illumination system 70 includes, for example, a light source 71, a condenser lens 72 that collects divergent light beams from the light source 71 and converts them into substantially parallel light, and a half mirror that reflects the light beams from the condenser lens 72 to illuminate the display element 51. Surface 73a
And the like. When a reflective display element is used in the image display device, it is necessary to arrange an illumination system for illuminating the reflective display element between the display element 51 and the small prism 52. Therefore, it is necessary to increase the distance between the prism 52 and the display element 51 as shown in FIG.

On the other hand, in the image display device proposed in Japanese Patent Application Laid-Open No. H11-125791, a non-telecentric image display device, a non-telecentric non-telecentric device having at least one eccentric back reflection surface without intermediate image formation is provided. In an image display device having an eyepiece optical system, a light source is disposed at a position substantially conjugate with an entrance pupil.

FIG. 17 shows a configuration specifically disclosed in the publication.

FIG. 17 is a first specific configuration diagram disclosed in Japanese Patent Application Laid-Open No. H11-125791.
2, a reflective LCD 108, a first surface 103 acting as a transmitting surface and a total reflecting surface, and a second surface 10 acting as a reflecting surface
4. The third surface 105 acting as a transmission surface is constituted by an eccentric optical system 110 filled with a medium having a refractive index larger than 1.

The light source 112 is conjugate with the exit pupil 101 by an optical system including the reflection type LCD 108 as a mirror and the decentered optical system 110 as a mirror, and the display surface of the display element and the display light incident on the decentered optical system. The light source means is arranged in a space between the surface and the space surrounding the surface and at a position outside the optical path which does not block the display light.

FIG. 18 and FIG.
FIG. 2 is a second and a third specific configuration diagram disclosed in Japanese Patent Application Laid-Open No. 1-127971, in which a light source 112, a reflective LCD 108,
An eccentric optical system 110 in which a first surface 103 acting as a transmission surface and a total reflection surface, a second surface 104 acting as a reflection surface, and a third surface 105 acting as a transmission surface are each filled with a medium having a refractive index larger than 1. Decentered optical system 1
The light source means is disposed at a position where a part of the display light can be illuminated by transmitting a portion or a direction through which a display light beam does not pass.

According to the publication, as shown in FIG. 20, a prism-shaped decentered optical element surrounded by decentered surfaces 103, 104, 105, and 106, and a decentered reflecting surface 11
No. 5 is also disclosed in which the light from the light source 112 passes through the prism-shaped decentered optical element, is reflected by the decentered reflection surface 115, and illuminates the reflective LCD 108 again through the prism-shaped decentered optical element. Have been.

[0015] Only the above-mentioned four types are disclosed in Japanese Patent Application Laid-Open No. 11-125791 in a form in which an image displayed on a reflection type LCD can be observed, including the arrangement of light sources.

[0016]

As described above, image display devices such as head-mounted displays and glasses-type displays are required to be smaller and lighter as a whole. In particular, in consideration of the weight balance, the appearance, and the like, it is desired to be thin in the visual axis direction of the observer. Further, it is an important issue to widen the observation angle of view.

In the configuration disclosed in Japanese Patent Application Laid-Open No. H11-125791, as shown in FIG.
The light from the light source 112 protrudes to the observer side, and the eye relief cannot be secured, or the angle difference between the principal rays of each angle of view to the reflective LCD becomes large, and the light is reflected by the light source 112. There is a tendency that the contrast in the screen greatly varies under the influence of the viewing angle characteristics of the LCD.

In the case of the configuration shown in FIG.
In the configuration of FIG. 19, from the right side in the figure from the vertical direction of the LCD 108, and from the left side in the figure from the vertical direction of the reflective LCD 108 in the configuration of FIG.
Since the divergent light from the light source illuminates the reflective LCD 108 through a part of the decentered optical system 110, the light rays farther from the light source have a smaller incident angle to the reflective LCD, and the viewing angle characteristics of the LCD Tend to cause contrast gradation.

In the configuration shown in FIG. 20, adjustment must be performed between the prism-shaped decentered optical element, the reflective LCD, and the decentered reflection surface, which are decentered from each other, during assembly, and the adjustment tends to be difficult. was there.

According to the present invention, when observing image information displayed on a reflective display means such as a liquid crystal display in a wide observation field, an illumination system for illuminating the display means and a light beam from the display means are guided to an observer's eyeball. By appropriately setting the configuration of an optical system for emitting light, for example, an optical unit including a prism having a refractive action, the size of the entire apparatus can be reduced, and in particular, the thickness of the eyepiece optical system in the visual axis direction of the observer can be reduced. It is an object of the present invention to provide an image display device which can observe the image information with a good image quality in a wide observation visual field while achieving the above.

Another object of the present invention is to provide an image display device in which the variation in contrast within a screen is small and an optical system which can be easily assembled and adjusted can be constituted.

[0022]

According to a first aspect of the present invention, there is provided an image display apparatus, comprising: a reflective display means; an incident surface on which a light beam is incident; A first optical element having a surface and at least one other surface, the interior of which is filled with the same material, an incident surface on which a light beam from the reflective display means is incident, and an optical path for reflecting the light beam incident from the incident surface A plurality of reflecting surfaces which are eccentric and have power with respect to the light, an emitting surface which emits light beams reflected by the plurality of reflecting surfaces and guides the light to an observer's pupil, and the inside of which is filled with the same material. An optical element, and at least a part of one surface other than the incident surface and the outgoing / incident surface of the first optical element and at least a part of the incident surface of the second optical element are joined directly or via an optical member. Luminous flux in at least a part of the joined surface Reflected by injection from said output incident surface is characterized by illuminating the display means of the reflection type.

According to a second aspect of the present invention, in the first aspect of the present invention, a light beam reflected by the reflective display means and incident on the first optical element from the outgoing / incoming surface is secondly transmitted from the joint of the joint surface. It is characterized by being guided to an optical element.

According to a third aspect of the present invention, in the second aspect of the present invention, the joint surface includes a reflection film forming portion and a non-reflection film forming portion, and the first optical element other than the light incident / incident surface and the joint surface. The light beam incident from the surface is reflected by the reflection film forming portion, exits the light entrance / exit surface, is guided to the reflection type display means, and the light beam from the reflection type display means is reflected by the reflection film non-formation portion. And guided to the second optical element.

According to a fourth aspect of the present invention, in the second aspect of the present invention, the joint surface is totally reflected by the non-joint portion of the luminous flux, exits the entrance / exit surface, is guided to the reflective display means, A light beam from a reflective display means is guided through the non-reflective film-forming portion to the second optical element.

According to a fifth aspect of the present invention, in the second aspect of the present invention, the joining surface is configured to function as a polarizing beam splitter.

According to a sixth aspect of the present invention, in the second aspect of the present invention, the joint surface is configured to function as a half mirror.

According to a seventh aspect of the present invention, in any one of the third to sixth aspects, the incident surface and the outgoing / incident surface of the first optical element have the same shape.

According to an eighth aspect of the present invention, in any one of the third to sixth aspects of the present invention, one of the plurality of power reflecting surfaces constituting the second optical element and the first optical element are provided. Is characterized in that the incident surface is a surface of the same shape.

According to a ninth aspect of the present invention, in the invention of any one of the third to sixth aspects, one of the plurality of power reflecting surfaces constituting the second optical element and the first optical element are provided. Is characterized in that the light incident and incident surfaces are surfaces having the same shape.

According to a tenth aspect of the present invention, in the invention of any one of the third to sixth aspects, an outgoing / incident surface of the first optical element and a reflecting surface having a plurality of powers of the second optical element are provided. , And the emission surface is constituted by different surfaces.

According to an eleventh aspect of the present invention, in the invention of any one of the third to sixth aspects, at least one of the plurality of power reflecting surfaces of the second optical element is a non-rotationally symmetric surface. It is characterized by:

According to a twelfth aspect of the present invention, in the invention of any one of the third to sixth aspects, at least one of the plurality of reflecting surfaces of the second optical element having a plurality of powers utilizes total reflection. It is characterized by having.

According to a thirteenth aspect of the present invention, in accordance with the eleventh or twelfth aspect, the plurality of curved reflecting surfaces of the second optical element have two surfaces, a first curved reflecting surface and a second curved reflecting surface. After the light beam reflected by the means and passed through a part of the first optical element is made incident on the incident surface of the second optical element, totally reflected by the first curved reflecting surface, and reflected by the second curved reflecting surface, It is characterized in that the light is emitted from the emission surface and guided to the observer.

According to a fourteenth aspect, in the eleventh or twelfth aspect, the plurality of curved reflecting surfaces of the second optical element are three of a first curved reflecting surface, a second curved reflecting surface, and a third curved reflecting surface.
A light beam from the display means is incident on the incident surface of the second optical element, reflected by the first curved reflecting surface, totally reflected by the second curved reflecting surface, and reflected by the third curved reflecting surface After that, the light is emitted from the emission surface and guided to the observer.

According to a fifteenth aspect of the present invention, in any one of the third to sixth aspects of the present invention, there is provided an optical system for imparting directivity to a light beam incident on the incident surface of the first optical element. It is characterized by:

According to a sixteenth aspect of the present invention, in any one of the third to sixth aspects, there is provided a polarizing means for causing a linearly polarized light beam to enter the first optical element.

According to a seventeenth aspect of the present invention, in any one of the third to sixth aspects of the present invention, an optical system for imparting directivity to a light beam incident on the incident surface of the first optical element, and a linearly polarized optical system. It is characterized by having a polarizing means for causing a light beam to enter the first optical element, wherein at least one of the optical system and the polarizing means is joined to the first optical element.

An eighteenth invention is characterized in that, in the invention of the second invention, at least one of the plurality of curved reflecting surfaces of the second optical element utilizes total reflection.

According to the nineteenth aspect of the present invention, the image display device guides the light to an incident surface S1 on which a light beam is incident and a surface S2 having a function of reflecting and transmitting the light beam from the incident surface S1.
A display element disposed opposite to the first exit surface is illuminated by using a first optical element having an exit surface S3 for emitting the light beam reflected by the light source 2, and the exit surface of the light beam from the display element is illuminated. A surface having a function of causing a light beam to enter from an incident surface S4 to which light is incident from S3 and at least partially joined to at least a part of the surface S2 directly or via an optical member, and reflecting and transmitting the light beam from the incident surface S4. Based on the display element using a reflecting surface S6 that guides the light to S5 and reflects the light beam reflected by the surface S5, and a second optical element that emits the light beam from the reflecting surface S6 from the surface S5. It is characterized in that an image is observed.

According to a twentieth aspect of the present invention, in the nineteenth aspect, each of the first and second optical elements has at least one asymmetrical aspherical surface and comprises a prism body filled with the same material. It is characterized by having.

A head-mounted display according to a twenty-first aspect of the present invention is characterized in that the image display device according to any one of the first to twentieth aspects can be mounted on the head or face of an observer.

[0043]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic view of a main part of a first embodiment of an image display device according to the present invention.

In this embodiment, only one eye when the image display device is applied to a head mounted display (HMD) that can be mounted on the observer's head is shown.

In the figure, 1 is a surface light source, 2 is a lens system, and 3 is a polarizing plate, which constitutes one element of the light source means. 1,2
And 3 may be arranged eccentrically, but it is preferable to arrange them coaxially because the light use efficiency is high.

B1 is a first optical element, and has a transmission surface S1,
It is a prism-shaped optical element having three optical surfaces, a surface S2 and a transmission surface S3, having a function of reflecting and transmitting, and the inside of which is filled with the same material. The transmitting surface S1 is an incident surface on which a light beam is incident, and the transmitting surface S3 is disposed so as to face the reflective display means, and has a function of emitting light to the reflective display means, and a function of displaying the reflective display means. It is an entrance / exit surface having the function of allowing light from the means to enter. Further, in the present embodiment, a reflective film such as a metal film or a dielectric film is formed on a part of the surface S2, the reflective film forming portion has a reflecting function, and the reflective film non-forming portion has a transmitting function. I'm making it.

Reference numeral 4 denotes a reflection type display means, which comprises a reflection type liquid crystal display (LCD).

B2 is a second optical element, which has a transmission surface S4,
A prism-shaped element having three optical surfaces, a curved surface S5 acting as a reflective surface and a transmissive surface, and a reflective curved surface S6 formed with a reflective film such as a metal film or a dielectric film, and the inside of which is filled with the same material. . The transmitting surface S4 is an incident surface on which a light beam from the reflective display means is incident, and the curved surfaces S5 and S6 are two reflecting surfaces having eccentricity and power with respect to the optical path of the light incident from the incident surface S4. Surface and curved surface S
An exit surface 5 emits a light beam and guides the light to the pupil of the observer.

The first optical element B1 and the second optical element B2 are
It is joined at a part of the surface S2 and a part of the surface S4.
Reference numeral 5 denotes a polarizing plate, which is disposed so that the polarizing axis of the polarizing plate 3 is substantially orthogonal to the polarizing plate.

Here, the surfaces S3, S5, S6 and the joint S24 between the surface S2 and the surface S4 are provided with an eyepiece optical system (observation optical system) for forming an enlarged virtual image of the image displayed on the reflective LCD 4.
IS.

In the present embodiment, the respective surfaces S3, S5, S5, S5 constituting the eyepiece optical system IS are arranged such that the eyepiece optical system IS becomes thinner in the visual axis direction of the observer's eye E (Z-axis direction in the figure). S6
Is decentered with respect to the optical path.

In particular, the reflecting surfaces S5 and S6 are eccentrically arranged. Above all, for the light beam reflected on the surface S5, when the refractive index of the material forming the second optical element B2 is n, the angle of incidence of the light ray finally guided to the pupil E of the observer on the surface S5 is It is largely eccentric so as to have an angle of arcsin (1 / n) or more, so that it is totally internally reflected. Also,
After the totally reflected light rays are reflected by the surface S6, the light is transferred to the surface S5.
The light is incident at an angle of csin (1 / n) or less, is refracted and transmitted through the surface S5, and is guided to the pupil E. Since the surface S5 serves as both a reflection surface and a transmission surface, there is an advantage in terms of cost due to a reduction in the number of surfaces, and light utilization efficiency is improved by making the reflection on the surface S5 a total reflection.

At this time, at least one of the curved surfaces S3, S5, and S6, which are components of the eyepiece optical system IS, has symmetry only in a direction (x-axis direction) perpendicular to the plane of FIG. However, it is preferable from the viewpoint of aberration correction that the asymmetrical aspherical surface having a symmetrical surface is used. In particular, the surface S6 having a strong power is preferably an asymmetrical aspherical surface from the viewpoint of aberration correction.

Further, when all of the surfaces S3, S5, and S6 are constituted by asymmetrical aspheric surfaces each having a symmetrical surface on the paper surface, aberration correction is further improved.

The optical operation of the image display device according to this embodiment will be described below with reference to FIG.

The light emitted from the surface light source 1 passes through the lens system 2 and
Only the S-polarized light component is transmitted through the polarizing plate 3 to form an S-polarized light beam. The S-polarized light beam enters the first optical element B1 from the surface S1 acting as the incident surface of the first optical element B1, is reflected by the reflection film forming portion of the surface S2 acting as the reflection surface and the transmission surface, Surface S acting as transmission surface
The illumination light flux emitted from the LCD 3 illuminates the reflective LCD 4.

Here, the luminous flux diverging from one point on the surface light source 1 is condensed, and an angle formed by the light beams constituting the light beam is reduced so as to enter the reflection type LCD 4 so as to be incident on a part of the light source means LS. The refractive power of a certain lens system 2 and the refractive power of the surface S3 of the first optical element B1 are configured. The illumination light beam illuminating the LCD 4 is a reflection type LCD based on the image information.
The light is appropriately modulated at 4.

For example, the polarization axis is set to 9
The LCD is rotated by 0 ° as P-polarized light, the S-polarized light remains in a non-display area, and the halftone is in a corresponding polarization state.
It is reflected at 4.

The reflected light flux enters the first optical element B1 again from the surface S3, and is guided to the portion of the surface S2 where the reflective film is not formed.
The light enters the second optical element B2 from a surface S24 where the surfaces S2 and S4 are joined.

Thereafter, the light is totally reflected by the curved surface S5 acting as a reflecting surface, is reflected by a curved surface S6 acting as a reflecting surface after being provided with a reflecting film, is again guided to the surface S5, and is transmitted from the surface S5 to the second optical element B2. And is guided to the polarizing plate 5. The polarizing plate 5 transmits the P-polarized light component and absorbs the S-polarized light component. As a result, a display light beam by the LCD 4 is formed.

The display light beam passing through the polarizing plate 5 is applied to the pupil E of the observer.
To reach. At this time, the observer makes the faces S3, S5, S6
The enlarged virtual image of the image based on the reflective LCD 4 is visually recognized by the refractive power of each surface of the eyepiece optical system IS including the joint S24 between the surface S2 and the surface S4.

According to this embodiment, the eyepiece optical system IS is thin in the direction of the observer's visual axis (Z-axis direction in the figure), and the light source means LS is arranged at a position where it does not protrude in the Z-axis direction. As a thin image display device. Further, with the above-described configuration, the principal ray of each angle of view to the reflective LCD 4 is reflected by the refractive power of the lens system 2 which is a part of the light source means LS and the refractive power of the surface S3 of the first optical element B1. The variation in the angle of incidence / reflection is reduced, and the difference in contrast within the screen due to the viewing angle characteristics of the reflective LCD 4 is reduced.

The first optical element B1 and the second optical element B
2 is joined, so that the optical member for positioning with the reflective LCD 4 is composed of one part, thereby facilitating the adjustment of each part.

In this embodiment, a reflection film is formed on a part of the surface S2 to provide a reflection function and provide a reflection function. However, the angle of total reflection at a non-joined portion not joined to the surface S4. , The light from the light source means LS may be incident.

With such a configuration, design restrictions are increased, but the labor for forming the reflective film can be omitted, and a cost reduction effect can be expected.

FIG. 2 is a schematic view of a main part of an image display device according to a second embodiment of the present invention. The difference between the present embodiment and the first embodiment is that the two transmission surfaces S constituting the first optical element B1 are different.
1, S3 is constituted by one curved surface, lens system 2
Is given to the curved surface S1, the lens system 2 is omitted, and the first optical element B1 and the second optical element B2 are
Are sandwiched between them, and the rest is the same as the first embodiment. In the figure, each component is denoted by the same reference numeral as in the first embodiment.

The optical operation of the image display device according to this embodiment will be described below with reference to FIG.

In the light emitted from the surface light source 1, only the S-polarized light component is transmitted through the polarizing plate 3 to form an S-polarized light beam.

The S-polarized light beam enters the first optical element B1 from a surface S1 acting as an incident surface of the first optical element B1,
The light is reflected by the reflection film forming portion of the surface S2 functioning as the reflection surface and the transmission surface, and is emitted from the surface S3 functioning as the entrance / exit surface to form an illumination light beam for illuminating the reflection type LCD 4. Here, the refractive power of the surface S1 of the first optical element B1 and the surface S1 are adjusted so that the angle between the light beams constituting the light beam diverging from one point on the surface light source 1 is reduced and the light beam enters the reflective LCD 4.
A refractive power of 3 is constituted.

The illumination light beam is reflected by the reflection type L based on the image information.
The light is appropriately modulated by the CD 4 and reflected. The display light beam based on the LCD 4 enters the first optical element B1 again from the surface S3,
The surface S2 is guided to the non-reflection film forming portion.

The polarizing plate 5 joined between the surface S2 and the surface S4 transmits only the P-polarized light component as the display light of the display light flux, and absorbs the S-polarized light component as the non-display light. , To the surface S <b> 4 joined to the polarizing plate 5. The display light flux enters the second optical element B2 from the surface S4 acting as the incident surface of the second optical element B2, and is totally reflected by the curved surface S5 acting as the reflecting surface. The light is reflected by the curved surface S6, is again guided to the surface S5, exits the second optical element B2 from the surface S5, and reaches the pupil E of the observer.

As described above, the reflection type LCD is provided to the observer.
In step 4, a virtual image of image information based on the light beam light-modulated is visually recognized. At this time, the observer magnified the image on the reflective LCD 4 due to the refractive power of each surface of the eyepiece optical system IS composed of the joints of the surfaces S3, S5, S6 and S2 with the polarizing plate 5 and the surface S4. I am looking at a virtual image.

According to the present embodiment, in addition to the effects described in the first embodiment, the transmission surface of the first optical element can be constituted by one surface, and the number of mirror surface pieces of the mold required for molding can be reduced. The manufacture of the optical element becomes easy.

Further, the power of the lens system 2 is given to the curved surface S1, and the polarizing plate 5 is joined between the first optical element B1 and the second optical element B2, so that the position can be reduced when assembling the HMD. The number of optical components to be combined is further reduced, and adjustment including the illumination system can be facilitated.

FIG. 3 is a schematic view of a main part of an image display device according to a third embodiment of the present invention. In the figure, the same elements as those in the first embodiment are denoted by the same reference numerals. Note that the difference between the present embodiment and the first embodiment is that the surface S3 of the first optical element B1 and the surface S6 of the second optical element B2 have the same surface shape, and are otherwise the same. .

Again, the surfaces S3, S5, S6 and the surface S
Part of the joint with S2 and S4 forms an eyepiece optical system IS that forms an enlarged virtual image of an image displayed on the reflective LCD 4.

In this embodiment, each of the surfaces S3, S5, S6 constituting the eyepiece optical system IS is connected to the optical path so that the eyepiece optical system IS becomes thinner in the direction of the observer's visual axis (the Z-axis direction in the figure). Is eccentric with respect to.

In particular, the reflecting surfaces S5 and S6 are eccentrically arranged. Above all, for the light beam reflected on the surface S5, when the refractive index of the material forming the second optical element B2 is n, the angle of incidence of the light ray finally guided to the pupil E of the observer on the surface S5 is The eccentricity is large so that the angle is more than arcsin (1 / n).

At this time, at least one of the curved surfaces S3, S5, and S6, which are components of the eyepiece optical system IS, has symmetry only in a direction (x-axis direction) perpendicular to the plane of FIG. However, it is preferable from the viewpoint of aberration correction that the asymmetrical aspherical surface having a symmetrical surface is used.

Further, when all of the surfaces S3, S5, and S6 are constituted by asymmetrical aspheric surfaces each having a symmetrical surface on the paper surface, aberration correction is further improved.

Hereinafter, the optical operation of the image display device according to this embodiment will be described with reference to FIG.

The light emitted from the surface light source 1 passes through the polarizing plate 3
Only the polarized light component is transmitted to form an S-polarized illumination light beam. The illumination light flux enters the first optical element B1 from a surface S1 acting as an incident surface of the first optical element B1, is reflected by a reflection film forming portion of a surface S2 acting as a reflection surface, and a surface S3 acting as an exit surface Then, an illumination light beam for illuminating the reflective LCD 4 is formed.

The illuminating light beam is reflected by a reflection type L based on image information.
The light is appropriately modulated and reflected by the CD 4. The light beam reflected by the LCD 4 enters the first optical element B1 again from the surface S3, is guided to the non-reflection film forming portion of the surface S2, and enters the second optical element B2 from the surface S4 joined to the surface S2.

Thereafter, the light is totally reflected by the curved surface S5 acting as a reflecting surface, is reflected by a curved surface S6 which is provided with a reflecting film and acts as a reflecting surface, is again guided to the surface S5, and is transmitted from the surface S5 to the second optical element B2. And is guided to the polarizing plate 5. The polarizing plate 5 transmits the P-polarized light component and absorbs the S-polarized light component to form a display light beam. The display light beam having passed through the polarizing plate 5 reaches the pupil E of the observer.

As described above, the reflection type LCD is provided to the observer.
4 is visually recognized.

In the present embodiment, the first optical element B1
Since the surface S3 and the surface S6 of the second optical element B2 have the same surface shape, there is also an advantage that the accuracy of joining the first optical element B1 and the second optical element B2 can be easily obtained.

In the above embodiment, the location where the illumination light is reflected on the surface S2 of the first optical element B1 and the reflection type LCD 4
However, as shown in each of the following embodiments, a portion where the illumination light is reflected and a portion where the reflected light beam from the reflective LCD 4 is transmitted are transmitted. The location may overlap.

FIG. 4 is a schematic view of a main part of a fourth embodiment of the image display device of the present invention. In the figure, 1 is a surface light source, 2 is a lens system, 3 is a polarizing plate, and these elements 1, 2, and 3 constitute one element of the light source means. B1 is a first optical element, which is a transmission surface S1, a half mirror surface S2, and a transmission surface S3.
Has three surfaces. 4 is a reflective liquid crystal display device (LC
D). B2 is a second optical element, and has a transmission surface S4,
Curved surface S5 acting as reflective surface and transmissive surface, reflective curved surface S
6. First optical element B1 and second optical element B2
Are joined at most of the half mirror surface S2 and most of the surface S4. Reference numeral 5 denotes a polarizing plate, which is disposed so that the polarizing axis of the polarizing plate 3 is substantially orthogonal to the polarizing plate.

Here, surfaces S3, S5, S6 and surfaces S2,
The junction of S4 constitutes an eyepiece optical system IS that forms an enlarged virtual image of the image displayed on the reflective LCD 4.

In this embodiment, each surface constituting the eyepiece optical system IS is decentered with respect to the optical path so that the eyepiece optical system IS becomes thin in the direction of the observer's visual axis (the Z-axis direction in the figure). Configuration.

In particular, the reflecting surfaces S5 and S6 are eccentrically arranged. Above all, for the light beam reflected on the surface S5, when the refractive index of the material forming the second optical element B2 is n, the angle of incidence of the light ray finally guided to the pupil E of the observer on the surface S5 is The eccentricity is large so that the angle is more than arcsin (1 / n).

At this time, at least one of the curved surfaces S3, S5 and S6, which are components of the eyepiece optical system IS, has symmetry only in a direction (x-axis direction) perpendicular to the plane of FIG. However, it is preferable from the viewpoint of aberration correction that the asymmetrical aspherical surface having a symmetrical surface is used.

Further, when all of the surfaces S3, S5, and S6 are constituted by asymmetric aspheric surfaces each having a symmetrical surface on the paper surface, aberration correction is further improved.

Hereinafter, the optical function of the image display device of this embodiment will be described with reference to FIG.

The light emitted from the surface light source 1 passes through the lens system 2 and
Only the S-polarized light component is transmitted through the polarizing plate 3 to form an S-polarized illumination light beam. The illumination light flux enters the first optical element B1 from a surface S1 acting as an incident surface of the first optical element B1, and is partially reflected and partially transmitted by a surface S2 acting as a half mirror. The light beam reflected by the surface S2 is emitted from the surface S3 acting as an exit surface and an incident surface to form an illumination light beam for illuminating the reflective LCD 4.

The illumination light beam is reflected by a reflection type L based on image information.
The light is appropriately modulated and reflected by the CD 4. The light beam reflected by the LCD 4 enters the first optical element B1 again from the surface S3, is guided to the half mirror surface S2, and is partially transmitted and partially reflected.

The display light beam enters the second optical element B2 from the surface S4 acting as the incident surface of the second optical element B2 joined to the surface S2, and is totally reflected by the curved surface S5 acting as a reflecting surface. S6 acting as a reflection surface
Are reflected again by the surface S5, and exit the second optical element B2 from the surface S5 and enter the polarizing plate 5.

The polarizing plate 5 transmits the P-polarized light component and absorbs the S-polarized light component to form a display light beam. The display light beam having passed through the polarizing plate 5 reaches the pupil E of the observer. In addition, since the polarizing plate 5 is arranged immediately before the pupil E of the observer, light traveling toward the pupil E in the S-polarized illumination light flux transmitted through the half mirror S2 is absorbed by the polarizing plate 5, and unnecessary light is generated. Is preventing.

As described above, the reflection type LCD is provided to the observer.
4 is visually recognized.

In the present embodiment, the reflection type L is formed by using the surface S2 as a half mirror to overlap the portion where the illumination light is reflected and the portion where the reflection light from the reflection type LCD is transmitted.
The angle between the display surface of the CD and the principal ray at each angle of view is made nearly perpendicular. For this reason, there is an advantage that a high-contrast image can be obtained over the entire screen even when a reflective LCD having a sharp change in viewing angle characteristics is used.

Note that, instead of using the surface S2 as a half mirror, the same operation and effect can be obtained by using a surface S4 joined to the surface S2 as a half mirror. This is the same in the embodiment described later.

Further, as shown in the fifth embodiment in FIG. 5, the surface S2 is formed as a film functioning as a polarizing beam splitter surface (PBS) so that the polarizing plate 5 functioning as an analyzer is formed.
May be omitted. In this case as well, the same configuration can be obtained even if the surface S4, which is the bonding surface, is provided with the PBS function.

In the configuration of the fourth embodiment shown in FIG. 4, the assembly adjustment can be simplified by joining all of the plurality of units.

FIG. 6 is a schematic view showing a main part of a sixth embodiment of the present invention. In FIG. 6, the lens system 2 and the polarizing plate 3, which constitute one element of the light source means LS, are joined to the first optical element B1,
Surface S2 of first optical element B1 and surface S4 of second optical element B2
The structure is the same as that of the embodiment 4 in FIG. 4 except that the polarizing plate 5 is interposed therebetween.

Hereinafter, the optical function of this embodiment will be described with reference to FIG.

The light emitted from the surface light source 1 is reduced in the degree of divergence of the luminous flux emitted from a point on the surface light source 1 by the lens system 2, and is joined between the lens system 2 and the first optical element B1. Only the S-polarized light component is transmitted through the polarizing plate 3 thus formed, and forms an S-polarized light beam.

The S-polarized light beam enters the first optical element B1 from the surface S1 acting as the incident surface of the first optical element B1,
A part is reflected and a part is transmitted by the surface S2 acting as a half mirror. The transmitted S-polarized light beam is absorbed by the polarizing plate 5, and the reflected S-polarized light beam is emitted from the surface S3 acting as an exit surface and an incident surface to form an illumination light beam for illuminating the reflective LCD 4.

The illuminating light beam is reflected by the reflection type L based on the image information.
The light is appropriately modulated by the CD 4 and reflected. The display light beam is on the surface S3.
Further, the light enters the first optical element B1 again, is guided to the surface S2 acting as a half mirror, and is partially reflected and partially transmitted. The reflected light returns to the surface light source 1, and of the transmitted display light flux, the S-polarized light component, which is non-display light, is absorbed by the polarizing plate 5 joined between the surfaces S <b> 2 and S <b> 4, and the display light Only the light beam of the P-polarized light component is transmitted and guided to the surface S4 joined to the polarizing plate 5.

The display light beam enters the second optical element B2 from the surface S4 acting as the incident surface of the second optical element B2, and is totally reflected by the curved surface S5 acting as the reflecting surface. The light is reflected by the curved surface S6 acting as, is again guided to the surface S5, exits the second optical element B2 from the surface S5, and reaches the pupil E of the observer.

As described above, the reflection type LCD is provided to the observer.
4 is visually recognized. At this time, the observer enlarges the image based on the reflective LCD 4 by the refracting power of each surface of the eyepiece optical system IS composed of the joints of the surfaces S3, S5, S6 and the surfaces S2, polarizing plates 5, S4. I am looking at a virtual image.

With this configuration, the number of optical components to be aligned at the time of assembling the HMD is further reduced, and the adjustment including the part of the light source means LS is facilitated.

Further, the reflection point of the illumination light and the reflection type LCD 4
Even in a configuration in which a portion through which a reflected light flux from the optical element is transmitted overlaps, one surface of the first optical element and one surface of the second optical element can be configured to have the same surface shape to facilitate joining accuracy. It is possible.

FIG. 7 is a schematic view of a main part of a seventh embodiment of the image display device of the present invention. In the drawing, the surface S1 of the first optical element and the surface S5 of the second optical element have the same surface shape, and the surface S2 of the first optical element B1 is a half mirror. Other symbols are the same as those in the above-described embodiment.

Hereinafter, the optical function of this embodiment will be described with reference to FIG.

Light emitted from the surface light source 1 passes through the lens system 2 and
Only the S-polarized light component is transmitted through the polarizing plate 3 to form an S-polarized illumination light beam. The illumination light flux enters the first optical element B1 from a surface S1 acting as an incident surface of the first optical element B1, and is partially reflected and partially transmitted by a surface S2 acting as a half mirror. The light beam reflected by the surface S2 is emitted from the surface S3 acting as an exit surface and an incident surface to form an illumination light beam for illuminating the reflective LCD 4.

The illumination light beam is reflected by the reflection type L based on the image information.
The light is appropriately modulated and reflected by the CD 4. The reflected light flux enters the first optical element B1 again from the surface S3, is guided to the half mirror surface S2, and is partially transmitted and partially reflected.

The display light beam enters the second optical element B2 from the surface S4 acting as the incident surface of the second optical element B2 joined to the surface S2, and is totally reflected by the curved surface S5 acting as a reflecting surface. S6 acting as a reflection surface
Are reflected again by the surface S5, and exit the second optical element B2 from the surface S5 and enter the polarizing plate 5.

The polarizing plate 5 transmits the P-polarized light component and absorbs the S-polarized light component to form a display light beam. The display light beam having passed through the polarizing plate 5 reaches the pupil E of the observer. In addition, since the polarizing plate 5 is arranged immediately before the pupil E of the observer, light traveling toward the pupil E in the S-polarized illumination light beam transmitted through the half mirror is absorbed by the polarizing plate 5 and unnecessary light is generated. I'm preventing.

As described above, the reflection type LCD is provided to the observer.
4 is visually recognized.

In the present embodiment, the first optical element B1
Since the surface S1 and the surface S5 of the second optical element B2 have the same surface shape, there is also an advantage that the accuracy of joining the first optical element B1 and the second optical element B2 can be easily obtained.

Further, it is possible to use a polarizing beam splitter (PBS) instead of a half mirror for the bonding surface.

FIG. 8 is a schematic diagram of a main part of an image display apparatus according to an eighth embodiment of the present invention. In the figure, the surface S1 of the first optical element and the surface S5 of the second optical element have the same surface shape, and the surface S2 of the first optical element B1 is a polarizing beam splitter (PBS).
It is. Other symbols are the same as those in the above-described embodiment.

Hereinafter, the optical function of the image display device according to the present embodiment will be described with reference to FIG.

The light emitted from the surface light source 1 passes through the lens system 2 and
Only the S-polarized light component is transmitted through the polarizing plate 3 to form an S-polarized illumination light beam. The light enters the first optical element B1 from a surface S1 acting as an incident surface of the first optical element B1,
To the surface S2 acting as The illumination light flux that is the S-polarized light is all reflected by the surface S2. The luminous flux of the S-polarized component reflected by the surface S2 is converted into a surface S acting as an exit surface and an entrance surface.
The illumination light flux emitted from the LCD 3 illuminates the reflective LCD 4.

The illumination light beam is reflected by the reflection type L based on the image information.
The light is appropriately modulated by the CD 4 and reflected. The reflected beam is the surface S3
Further, the light enters the first optical element B1 again, is guided to the PBS surface S2, transmits only the P-polarized light component, and reflects the S-polarized light component to form a display light flux. The display light flux enters the second optical element B2 from a surface S4 acting as an incident surface of the second optical element B2 joined to the surface S2, and is totally reflected by a curved surface S5 acting as a reflecting surface, and then is provided with a reflecting film. The light is reflected by the curved surface S6 acting as a reflecting surface, is again guided to the surface S5, and
From 5, the second optical element B2 is emitted and reaches the pupil E of the observer.

As described above, the reflection type LCD is provided to the observer.
The virtual image of the image information displayed in 4 is visually recognized.

According to the present embodiment, since the surface S2 is made of PBS, the light use efficiency is higher than that of the sixth embodiment. Further, the polarizing plate 5 acting as an analyzer becomes unnecessary.

It is also possible to omit the polarizing plate 3 acting as a polarizer.

FIG. 9 is a schematic diagram showing a main part of a ninth embodiment of the image display device of the present invention. The difference between the present embodiment and the eighth embodiment is that a part of the reflection surface S6 of the second optical element B2 is formed as a non-reflection film forming portion, and the reference numerals in FIG. Is the same as

The optical operation of the image display device according to the present embodiment will be described below with reference to FIG.

Light emitted from the surface light source 1 passes through the lens system 2 and
A surface S2 which enters the first optical element B1 from a surface S1 acting as an incident surface of the first optical element B1 and acts as a PBS.
Reflects only the S-polarized component and transmits the P-polarized component.
At this time, the transmitted P-polarized component light is
After entering the optical element, the reflection surface S6 of the second optical element B2
The angle of incidence on the surface S2 is set so that the light exits from the non-reflection film-forming portion of the, so that unnecessary light is not guided to the pupil E. The luminous flux of the S-polarized light component reflected by the surface S2 is emitted from the surface S3 acting as an exit surface and an incident surface to form an illumination luminous flux for illuminating the reflective LCD 4.

The illuminating light beam is reflected by the reflection type L based on the image information.
The light is appropriately modulated by the CD 4 and reflected. The reflected beam is the surface S3
Further, the light enters the first optical element B1 again, is guided to the PBS surface S2, transmits only the P-polarized light component, and reflects the S-polarized light component to form a display light flux. The display light flux enters the second optical element B2 from a surface S4 acting as an incident surface of the second optical element B2 joined to the surface S2, and is totally reflected by a curved surface S5 acting as a reflecting surface, and then is provided with a reflecting film. The light is reflected by the curved surface S6 acting as a reflecting surface, is again guided to the surface S5, and
From 5, the second optical element B2 is emitted and reaches the pupil E of the observer. As described above, the observer visually recognizes the virtual image of the image information displayed on the reflective LCD 4.

According to this embodiment, a polarizer for aligning the polarization of the illumination light beam is not required. Also, in the case of the half mirror configuration as in the seventh embodiment, similarly, by setting the incident angle of the illumination light on the surface S2 so that unnecessary light is not guided to the pupil E, the polarization plate 3 or the polarization plate 5 One can be unnecessary.

A function for reducing the variation in the angle of incidence between the light beams with respect to the light beam diverging from one point on the surface light source and entering the reflection type image display element, such as the lens system 2, is provided. It is also possible to provide the first optical element and the second optical element with a joint surface.

FIG. 10 is a schematic view of a main part of an image display apparatus according to a tenth embodiment of the present invention. This embodiment differs from the configuration of the seventh embodiment in FIG. 7 in that the reflecting surface S2 of the first optical element B1 and the surface S4 of the second optical element B2 joined thereto are curved surfaces, and the lens system 2 is omitted. Reference numerals and other configurations in the figure are the same as those in the sixth embodiment.

Hereinafter, the optical function of the image display device of this embodiment will be described with reference to FIG.

Light emitted from the surface light source 1 passes through the polarizing plate 3
Only the polarized light component is transmitted to form an S-polarized illumination light beam. The illumination light flux enters the first optical element B1 from a surface S1 acting as an incident surface of the first optical element B1, and is partially reflected and partially transmitted by a surface S2 acting as a half mirror. The light beam reflected by the surface S2 is emitted from the surface S3 acting as an emission surface, and forms an illumination light beam for illuminating the reflective LCD 4.

The illumination light beam is reflected by the reflection type L based on the image information.
The light is appropriately modulated and reflected by the CD 4. The reflected light flux enters the first optical element B1 again from the surface S3, is guided to the half mirror surface S2, and is partially transmitted and partially reflected. The display light flux enters the second optical element B2 from a surface S4 acting as an incident surface of the second optical element B2 joined to the surface S2, and is totally reflected by a curved surface S5 acting as a reflecting surface.
The light is reflected by the curved surface S6, which is provided with a reflective film and acts as a reflective surface, and is again guided to the surface S5.
2 is incident on the polarizing plate 5. The polarizing plate 5 transmits the P-polarized light component and absorbs the S-polarized light component to form a display light beam. The display light beam having passed through the polarizing plate 5 reaches the pupil E of the observer.

Further, since the polarizing plate 5 is disposed immediately before the pupil E of the observer, light traveling toward the pupil E in the S-polarized illumination light beam transmitted through the half mirror S2 is absorbed by the polarizing plate 5 and becomes unnecessary. Prevents the generation of light.

As described above, the reflection type LCD is provided to the observer.
4 is visually recognized.

According to the present embodiment, the first optical element and the second optical element provide the power for reducing the angle between the light beams with respect to the light flux diverging from one point on the surface light source and entering the reflection type image display element. Lens system 2
And the number of parts can be reduced.

In the above-described embodiments, the second optical element is used as the second optical element, a transmission surface S4 joined to the first optical element, a surface S5 acting as a total reflection surface and a transmission surface, and a surface S6 provided with a reflection film.
Although the three surfaces are arranged with the same material interposed therebetween, the present invention is not limited to this configuration.

FIG. 11 is a schematic view showing a main part of an image display apparatus according to Embodiment 11 of the present invention.

In the figure, 1 is a surface light source, 2 is a lens system, 3 is a polarizing plate, and each of the elements 1, 2 and 3 constitutes one element of the light source means LS. B1 is a first optical element, which has three optical surfaces of a transmission surface S1, a half mirror surface S2, and a transmission surface S3. Reference numeral 4 denotes a reflective liquid crystal display (LCD).

B2 is a second optical element, and has a transmission surface S4,
It has a curved surface S15 acting as a reflecting surface, a curved surface S16 acting as a total reflecting surface, a curved surface S17 acting as a reflecting surface, and a transmitting surface S18. The first optical element B1 and the second optical element B2 are joined at a half mirror surface S2 and a surface S4. Reference numeral 5 denotes a polarizing plate, which is disposed so that the polarizing axis of the polarizing plate 3 is substantially orthogonal to the polarizing plate.

Here, the first optical element B1 and the second optical element B2 each have a prism shape made of the same material, and the optical surfaces S1, S2, S
The surface 3 and the surfaces S4, S15, S16, S17, S18 are arranged eccentrically with respect to an optical path passing through the surface light source 1, the reflective LCD 4, and the designed pupil.

At this time, the surface S3 constituting the first optical element B1, the surfaces S15, S16 constituting the second optical element B2,
At least one surface of S17 and S18 is shown in FIG.
It is preferable from the viewpoint of aberration correction to have symmetry only in a direction (x-axis direction) perpendicular to the sheet of FIG.

Furthermore, when a plurality of surfaces from the above-mentioned surfaces are each constituted by an asymmetric aspherical surface having symmetry only in a direction perpendicular to the paper surface (x-axis direction) and having the paper surface as a symmetric surface,
This is desirable because aberration correction is further improved.

Hereinafter, the optical function of the image display device of this embodiment will be described with reference to FIG.

Light emitted from the surface light source 1 passes through the lens system 2 and
Only the S-polarized light component is transmitted through the polarizing plate 3 to form an S-polarized illumination light beam. The illumination light flux enters the first optical element B1 from a surface S1 acting as an incident surface of the first optical element B1, and is partially reflected and partially transmitted by a surface S2 acting as a half mirror. The light beam reflected by the surface S2 exits from the surface S3 acting as an exit surface, and
To form an illumination light flux for illuminating the light.

The illuminating light beam is reflected by the reflection type L based on the image information.
The light is appropriately modulated by the CD 4 and reflected. The reflected light flux enters the first optical element B1 again from the surface S3, is guided to the half mirror surface S2, and is partially transmitted and partially reflected.

The display light flux enters the second optical element B2 from the surface S4 acting as the incident surface of the second optical element B2 joined to the surface S2, and is reflected by the curved surface S15 provided with a reflective film and acting as a reflective surface. Later, the curved surface S acting as a total reflection surface
At 16, the light is reflected by a curved surface S17 which is provided with a reflection film and acts as a reflection surface, is guided to a transmission surface S18, exits the second optical element B2 from the surface S18, and enters the polarizing plate 5. The polarizing plate 5 transmits the P-polarized light component and absorbs the S-polarized light component to form a display light beam. The display light beam having passed through the polarizing plate 5 reaches the pupil E of the observer. In addition, since the polarizing plate 5 is arranged immediately before the pupil E of the observer, light traveling toward the pupil E in the S-polarized illumination light beam transmitted through the half mirror is absorbed by the polarizing plate 5 and unnecessary light is generated. I'm preventing.

As described above, the reflection type LCD is provided to the observer.
4 is visually recognized.

Each of the above embodiments is an example for explaining an example of the present invention, and the present invention is applicable to the following configurations.

The surface light source exemplified as one element of the light source means is a light emitting device having a substantially point light source such as an LED or a substantially linear light source such as a cold cathode tube and an optical system such as a lens or a concave mirror. Type that illuminates the diffusion plate of multiple LEs
A light emitting element having a substantially point light source such as D is one-dimensionally arrayed, or a side light type in which light from a light emitting element having a substantially linear light source such as a cold-cathode tube enters from the side surface of the light guide plate can be used. .

As a reflection type image display element, a reflection type LC
D has been described as an example in which a polarized illumination light beam is modulated by changing the degree of optical rotation for each pixel, but various types of reflective image display elements can be applied.

For example, an element which performs binary modulation such as a ferroelectric liquid crystal (FLC) is used as a reflection type LCD, and the frame time for displaying an image is divided into time required for gradation expression, and ON / OFF is performed. May be controlled so as to output gradation.

FLC has a better viewing angle characteristic than TN liquid crystal or the like, and a relatively high contrast can be obtained even when the reflective LCD is illuminated at a large incident angle as in the first to third embodiments.

Further, if a single polarizing plate type is used as the reflective LCD, it is not necessary to arrange polarizing plates substantially orthogonal to each other on the illumination optical path and the optical path of the reflective LCD. A configuration in which one polarizing plate is disposed immediately before is also possible, and the configuration can be simplified.

That is, it is also possible to configure as shown in FIG. FIG. 12 is a schematic view of a main part of Embodiment 12 of the present invention. In this embodiment, a single polarizing plate type reflective LCD 4a is applied to the same optical system configuration as in the first embodiment, and the light diverging from the light source 1 is weakened by the lens system 2 to reduce the degree of divergence and the surface S1 After being incident on the first optical element B1 and reflected by the reflection film forming portion on the surface S2, the surface S
The first optical element is emitted from 3 to illuminate the LCD 4a.

In the LCD 4a, the light which has been appropriately modulated enters the first optical element B1 from the surface S3, enters the second optical element B2 from the surface S4 joined to a part of the surface S2, and
After being totally reflected at 5, the light is reflected at the surface S6, is transmitted through the surface S5 this time, and is guided to the pupil E of the observer, so that an image based on the LCD 4a can be observed.

As a reflection type display element, a digital micromirror device (Digital Micromirror device) using a mirror array in which a plurality of mirrors are two-dimensionally arranged at a minute pitch.
It is also possible to use a cromirror device (DMD).

In this case, neither a polarizing plate for polarizing the illumination light beam nor a polarizing plate as an analyzer is required, and a simple configuration can be achieved. That is, it is also possible to configure as shown in FIG. FIG. 13 shows Embodiment 1 of the present invention.
3 is a schematic diagram of a main part of FIG.

In the present embodiment, the DMD 4b is applied to the same optical system configuration as in the first embodiment.
In the present embodiment, each of the micromirrors constituting the DMD is at an angle of 0 ° with respect to the DMD display surface (display is entirely white), and the dotted line indicates that each of the micromirrors constituting the DMD is tilted at a predetermined angle. In the embodiment, this is in an OFF state (entire black display).

Hereinafter, the operation will be described. The light diverging from the light source 1 is made to enter the first optical element B1 from the surface S1 with the degree of divergence weakened by the lens system 2, reflected by the reflection film forming portion of the surface S2, and then emitted from the surface S3. To illuminate the DMD 4b.

Pixels displayed in white on the DMD 4b are incident on the first optical element B1 from the surface S3 as shown by solid lines in the drawing, and are incident on the second optical element B2 from the surface S4 joined to the surface S2. The light enters, is totally reflected by the surface S5, is reflected by the surface S6, is transmitted through the surface S5, and is guided to the pupil E of the observer. In a pixel that displays black, the micromirror forming the DMD 4b is tilted so as to return to the direction in which the illumination light has entered the DMD 4b, as indicated by the dotted line in the figure, and the first optical element is shifted from the surface S3. The light enters B1, is reflected by the reflection film forming portion of the surface S2, exits from the surface S1, returns to the light source 1 through the lens system 2, and is not guided to the pupil of the observer.

The time for the white display state and the black display state of the pixel representing the halftone is appropriately adjusted according to the gradation so that light is guided to the pupil E only during the white display state. Has become.

As described above, an image based on the DMD 4b can be observed. Also in the present embodiment, the light source 1 is configured such that LEDs of three colors of RGB are sequentially turned on or fluorescent tubes of three colors of RGB, which can blink at high speed, are sequentially turned on, and corresponding images are displayed on the DMD 4b in accordance with the lighting of each color. Then, color display can be performed.

In each of the above embodiments, the light source may be omitted and external light (natural light) may be used.

Further, the image display device S of each of the above embodiments is described.
21 are provided for the left and right eyes of the observer as shown in FIG. 21, whereby a binocular head mounted display can be formed.

For example, if binocular parallax is used as an image to be displayed on the display element, an image observation system capable of stereoscopic viewing can be constructed.

It is needless to say that a monocular HMD in which only one unit is provided for either the left or right eye, not necessarily for both eyes, may be used.

As described above, according to each embodiment of the present invention, a case where a transmissive display device is used is described.
An image display device suitable for a head-mounted display capable of reducing the size of the entire device without causing a reduction in specifications such as an eye relief and an angle of view and capable of satisfactorily observing image information displayed on a reflective display device. This makes it possible to provide an image display device having an optical system configuration that is easy to assemble and adjust, with little variation in contrast within a screen.

[0174]

According to the present invention, when observing image information displayed on a reflective display means such as a liquid crystal display in a wide observation field, an illumination system for illuminating the display means and a luminous flux from the display means are observed by an observer. By appropriately setting the configuration of an optical system for guiding light to the eyeball, for example, an optical unit including a prism having a refractive action, the size of the entire apparatus can be reduced.
In particular, it is possible to achieve an image display device capable of observing the image information with a good image quality in a wide observation visual field while reducing the thickness of the eyepiece optical system portion in the visual axis direction of the observer.

In addition, according to the present invention, it is possible to achieve an image display device in which the variation in contrast within the screen is small and an optical system that can be easily assembled and adjusted can be formed.

[Brief description of the drawings]

FIG. 1 is a schematic view of a main part of an image display device according to a first embodiment of the present invention.

FIG. 2 is a schematic view of a main part of an image display device according to a second embodiment of the present invention.

FIG. 3 is a schematic diagram of a main part of a third embodiment of the image display device of the present invention.

FIG. 4 is a schematic view of a main part of an image display device according to a fourth embodiment of the present invention.

FIG. 5 is a schematic diagram of a main part of an image display device according to a fifth embodiment of the present invention.

FIG. 6 is a schematic view of a main part of an image display device according to a sixth embodiment of the present invention.

FIG. 7 is a schematic view of a main part of an image display device according to a seventh embodiment of the present invention.

FIG. 8 is a schematic diagram of a main part of an image display device according to an eighth embodiment of the present invention.

FIG. 9 is a schematic view of a main part of a ninth embodiment of an image display device according to the present invention.

FIG. 10 is a schematic diagram of a main part of an image display device according to a tenth embodiment of the present invention.

FIG. 11 is a schematic view of a main part of an image display device according to an eleventh embodiment of the present invention.

FIG. 12 is a schematic view of a main part of a twelfth embodiment of the image display device of the present invention.

FIG. 13 is a schematic diagram of a main part of an image display device according to a thirteenth embodiment of the present invention.

FIG. 14 is a schematic view of a main part of a conventional image display device.

FIG. 15 is a schematic view of a main part of a conventional image display device.

FIG. 16 is a schematic view of a main part of a conventional image display device.

FIG. 17 is a schematic view of a main part of a conventional image display device.

FIG. 18 is a schematic view of a main part of a conventional image display device.

FIG. 19 is a schematic view of a main part of a conventional image display device.

FIG. 20 is a schematic view of a main part of a conventional image display device.

FIG. 21 is an external view of a main part of a head mounted display of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Surface light source 2 ... Lens system 3 ... Polarizing plate 4 ... Reflection type liquid crystal display device (LCD) 5 ... Polarizing plate (Polarizing axis is orthogonal to polarizing plate 3) B1 ... · First optical element B2 ··· Second optical element LS · · · Light source means IS · Eyepiece optical system

Continued on the front page F term (reference) 2H088 EA10 HA18 HA20 HA21 HA22 HA24 HA28 MA02 MA13 MA16 MA20 5G435 AA01 AA18 BB12 BB16 BB17 DD04 DD09 DD10 EE22 FF03 FF05 FF07 FF08 FF12 GG02 GG03 GG08 GG09 GG28 LL00

Claims (21)

[Claims] 1. A reflection type display means, an incident surface on which a light beam is incident, an outgoing / incident surface opposed to the reflection type display means for emitting and entering a light beam, and at least one other surface, and the inside is the same. A first optical element filled with a material, an incident surface on which a light beam from the reflective display means is incident, a plurality of reflecting surfaces decentered and having power with respect to an optical path for reflecting the light beam incident from the incident surface; An exit surface for emitting a light beam reflected by the plurality of reflection surfaces and guiding the light beam to the pupil of the observer; and a second optical element whose inside is filled with the same material; and an entrance surface of the first optical element. , At least a part of one surface other than the outgoing / incident surface and at least a part of the incident surface of the second optical element are joined directly or via an optical member, and a light beam is emitted by at least a part of the joined surface. The light is reflected and emitted from the entrance / exit surface to form the reflection type table. An image display device comprising illuminating means. 2. A light beam reflected by said reflection type display means and incident on said first optical element from said outgoing / incident surface is guided to a second optical element from a joint of said joint surface. Item 1. The image display device according to Item 1. 3. The joining surface includes a reflection film forming portion and a non-reflecting film forming portion, and a light beam incident from a surface of the first optical element other than the outgoing / incident surface and the joining surface forms the reflection film. The reflected light is emitted from the entrance / exit surface to be guided to the reflective display means, and the light flux from the reflective display means is passed through the non-reflection film forming part and guided to the second optical element. 3. The image display device according to claim 2, wherein: 4. The joint surface is totally reflected by the non-joint portion of the light beam, exits the light entrance / exit surface, is guided to the reflection type display means, and reflects the light beam from the reflection type display means into the reflection type display means. The image display device according to claim 2, wherein the light is guided to the second optical element through a non-film-forming portion. 5. The image display device according to claim 2, wherein said bonding surface is configured to function as a polarizing beam splitter. 6. The image display device according to claim 2, wherein said joining surface is configured to function as a half mirror. 7. The image display device according to claim 3, wherein an incident surface and an outgoing and incident surface of said first optical element have the same shape. 8. The apparatus according to claim 1, wherein one of a plurality of power reflecting surfaces constituting said second optical element and an incident surface of said first optical element have the same shape. 3
7. The image display device according to any one of claims 1 to 6. 9. A surface of one of a plurality of reflecting surfaces having a plurality of powers constituting said second optical element, and an outgoing / incident surface of said first optical element having the same shape. Item 7. The image display device according to any one of Items 3 to 6. 10. An outgoing / incident surface of said first optical element, an incident surface,
The image display device according to claim 3, wherein the reflection surface and the emission surface having a plurality of powers of the second optical element are configured by different surfaces, respectively. 11. An image display according to claim 3, wherein at least one of the plurality of power reflecting surfaces of said second optical element is a non-rotationally symmetric surface. apparatus. 12. The image according to claim 3, wherein at least one of the plurality of reflecting surfaces of the second optical element having a plurality of powers uses total reflection. Display device. 13. The plurality of curved reflecting surfaces of the second optical element have two surfaces of a first curved reflecting surface and a second curved reflecting surface, and a part of the first optical element which is reflected by the display means and is part of the first optical element. The transmitted light flux is made incident from the incident surface of the second optical element, totally reflected by the first curved reflecting surface, reflected by the second curved reflecting surface, emitted from the exit surface, and guided to the observer. 13. The image display device according to claim 11, wherein: 14. A plurality of curved reflecting surfaces of said second optical element, wherein said plurality of curved reflecting surfaces are a first curved reflecting surface, a second curved reflecting surface, and a third curved reflecting surface.
A light beam from the display means is incident on the incident surface of the second optical element, reflected by the first curved reflecting surface, totally reflected by the second curved reflecting surface, and reflected by the third curved reflecting surface 13. The image display device according to claim 11, wherein the image display device emits light from an emission surface and guides the light to an observer. 15. An image display according to claim 3, further comprising an optical system for giving directivity to a light beam incident on the incident surface of said first optical element. apparatus. 16. An image display apparatus according to claim 3, further comprising a polarizing means for causing a linearly polarized light beam to enter said first optical element. 17. An optical system for providing directivity to a light beam incident on an incident surface of the first optical element, and a polarizing means for causing a linearly polarized light beam to enter the first optical element. The image display device according to any one of claims 3 to 6, wherein at least one of the optical system and the polarizing means and the first optical element are joined. 18. The image display apparatus according to claim 2, wherein at least one of the plurality of curved reflecting surfaces of the second optical element utilizes total reflection. 19. An incident surface S1 on which a light beam enters and a surface S having a function of reflecting and transmitting the light beam from the incident surface S1.
2 is used to illuminate a display element disposed opposite to the first exit surface, using a first optical element having an exit surface S3 for guiding the light beam reflected by the surface S2 to emit a light beam reflected by the surface S2. Out of the light beam from the light exiting surface S3, the light beam is incident on at least a portion of the surface S2 directly or through an optical member from an incident surface S4 at least partially joined via an optical member.
Surface S5 having a function of reflecting and transmitting the light beam from the surface S5, and reflecting the light beam reflected by the surface S5.
6. An image display device, wherein an image based on the display element is observed using a second optical element configured to emit a light beam from the reflection surface S6 from the surface S5. 20. The image according to claim 19, wherein each of said first and second optical elements has at least one asymmetrical aspherical surface and is formed of a prism body whose inside is filled with the same material. Display device. 21. A head-mounted display, wherein the image display device according to claim 1 is configured to be mounted on a head or a face of an observer.