JP2007286317A - Mount type display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain the deterioration of image quality in a mount type display device. <P>SOLUTION: The mount type display device is equipped with: an image display means equipped with an image display element; a transparent substrate having a first surface and a second surface nearly parallel with each other and propagating luminous flux from the image display means; and a combiner element formed on the transparent substrate and superposing environmental light on the luminous flux from the image display means. The transparent substrate has a light shielding part equipped with a light shielding surface nearly perpendicular to the longitudinal direction of the transparent substrate. It is also good to totally reflect luminous flux from the image display means at least once on at least either the first surface or the second surface and then propagate it through the transparent substrate. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a wearable display device having image display means.

In recent years, a wearable display device using a small image display element has been considered (for example, see Patent Document 1). In such a wearable display device, a thin transparent substrate is used, and external light and a display image by the image display element are superimposed and guided to the observer's pupil.
JP 2005-84522 A

However, if the transparent substrate is made smaller and thinner in a situation where the light beam is propagated using total reflection, unnecessary reflected light may be generated. This unnecessary reflected light becomes ghost, glare, and the like, leading to deterioration in image quality of the image observed by the observer.
An object of the present invention is to suppress deterioration of image quality in a wearable display device.

  A wearable display device according to the present invention includes an image display means including an image display element, a transparent substrate having first and second surfaces that are substantially parallel to each other, and that transmits a light beam from the image display means, A combiner element that is formed in the transparent substrate and superimposes external light and the light beam from the image display means, and the transparent substrate has a light shielding portion having a light shielding surface substantially perpendicular to the longitudinal direction of the transparent substrate. It is characterized by having.

Preferably, the transparent substrate may propagate the light flux from the image display means by being totally reflected at least once at least one of the first surface and the second surface.
Preferably, the light-shielding portion has a center with respect to a first position where a chief ray of a light beam from a center of the image display element is totally reflected on the first surface or the second surface. You may arrange | position in the 2nd position facing the said 1st position on the other surface.

Preferably, the light shielding portion includes the first position and has a rectangular shape in a cross section substantially perpendicular to the longitudinal direction of the transparent substrate, and the area thereof is not more than half of the area of the transparent substrate in the cross section. It may be.
Preferably, the light-shielding portion includes the first position, and a curve having a radius of curvature different in accordance with a distance from the first position in a cross section substantially perpendicular to the longitudinal direction of the transparent substrate, It may have a shape sandwiched between straight lines corresponding to the other surface, and the area thereof may be half or less of the area of the transparent substrate in the cross section.

Preferably, the light-shielding surface of the light-shielding part may absorb the dominant wavelength of the light beam from the image display means.
Preferably, the light shielding surface of the light shielding part may reflect a dominant wavelength of a light beam from the image display means.

  ADVANTAGE OF THE INVENTION According to this invention, the fall of an image quality can be suppressed in a wearable display apparatus.

<First Embodiment>
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is an external view of the wearable display device 1 of the present embodiment. As shown in FIG. 1, the wearable display device 1 of the present embodiment includes a transparent substrate 12 for image display embedded in a lens portion of a frame 11 having a structure similar to that of a spectacle frame, and an image display unit 13 in the frame 11. It is fixed.

When the wearable display device 1 is mounted on the user's head by the frame 11, the transparent substrate 12 is disposed in front of the observation eye E, and the image display unit 13 is disposed at a position that does not obstruct the view of the observation eye E. Is done.
FIG. 2 is a schematic cross section of an optical system portion of the wearable display device 1. As shown in FIG. 2, the optical system portion includes an illumination optical system 14, an image display element 15, a collimator lens 16, a transparent substrate 12, and the like. Among these, the illumination optical system 14, the image display element 15, and the collimator lens 16 are housed in the image display unit 13. The optical member (here, the transparent substrate 12) that is disposed in front of the observation eye E and superimposes the display light flux from the image display element 15 and the external light flux from the outside is a so-called “image combiner”.

The illumination optical system 14 is, for example, an optical system that combines an LED and a diffusion plate. The image display element 15 is, for example, a transmissive LCD or an organic EL display. The transparent substrate 12 is made of an optical material that is transparent to visible light, such as glass or plastic, and is a parallel flat plate in which the user-side surface 121 and the non-user-side (outside side) surface 122 are parallel.
Inside the transparent substrate 12, a first reflecting surface 123 on which aluminum or the like is deposited, a second reflecting surface 124 having a hologram element, and light shielding portions 125a to 125c are formed. Among these, the 1st reflective surface 123 is formed in the vicinity of the position which opposes the image display part 13, and the attitude | position is an attitude | position inclined only by the predetermined angle with respect to the surface 121 and the surface 122 of the transparent substrate 12. FIG. The second reflecting surface 124 is formed in the vicinity of the position facing the observation eye E, and the posture thereof is a posture inclined by a predetermined angle with respect to the surface 121 and the surface 122 of the transparent substrate 12. Details of the light shielding portions 125a to 125c will be described later.

  In the above-described wearable display device 1, the image display element 15 is illuminated from behind by the illumination optical system 14, and spatially modulates the incident light to generate a light beam for image display (display light beam). The display light beam becomes a parallel light beam in the collimator lens 16 and is guided from the surface 121 of the transparent substrate 12 into the transparent substrate 12. In FIG. 2, only the chief ray of the light beam from the center of the image display element 15 is shown.

  The display light beam incident on the transparent substrate 12 is reflected by the first reflecting surface 123 at an angle smaller than 45 °, and then incident on the surface 121 of the transparent substrate 12 at an angle larger than the critical angle and totally reflected. Thereafter, the display light beam is incident on the surface 122 of the transparent substrate 12 at the same angle as the incident angle with respect to the surface 121 described above, and is totally reflected. Then, when the display light beam repeats internal reflection on the surface 121 and the surface 122 of the transparent substrate 12 and propagates in the direction of the observation eye E, it enters the second reflection surface 124 and receives a reflection action. The reflected display light beam passes through the surface 121 and exits from the transparent substrate 12 and enters an external predetermined region EP.

When the pupil of the observation eye E is arranged at any location in the predetermined area EP, the user can observe the enlarged virtual image of the image display element 15 at infinity on the outside side. That is, the predetermined area EP functions as an exit pupil.
In addition, at least a part of the external light flux that enters the transparent substrate 12 from the outside world passes through the transparent substrate 12 and the second reflecting surface 124 and enters the exit pupil EP. Therefore, the user can observe the scenery of the outside world together with the enlarged virtual image.

  As the image display element 15, an image display element such as a reflective LCD or a self-luminous element may be used. Moreover, although the example using the collimator lens 16 was shown, instead of the collimator lens 16, one or a plurality of optical surfaces having the same function as the collimator lens 16 are displayed from the image display element 15 to the first reflection surface 123. You may provide in any location of the optical path of a light beam.

  1 and 2 show an example in which the image display element 15 is disposed in the vicinity of the transparent substrate 12. However, the image display element 15 is disposed in an appropriate position away from the transparent substrate 12, and is disposed in the vicinity of the transparent substrate 12 by a relay optical system. The light may be guided up to. Further, an aerial image may be formed at the same position using a scanning optical system. 1 and 2 show an example in which the image display unit 13 is disposed on the user side of the transparent substrate 12, but it may be disposed on the outside of the transparent substrate 12 or in the vicinity of the side of the frame 11. You may arrange in. In any case, the inclination direction of the first reflecting surface 123 may be adjusted as appropriate. 1 and 2 show an example in which the image display unit 13 is arranged in the vicinity of the user's temporal region. However, if the user's field of view is not disturbed, for example, the user's view above the observation eye E It may be arranged near the forehead.

  Next, the light shielding portions 125a to 125c, which are features of the present invention, will be described. As illustrated in FIG. 2, the light shielding portions 125 a to 125 c have light shielding surfaces that are substantially perpendicular to the longitudinal direction of the transparent substrate 12. The light shielding portions 125 a to 125 c are centered at a position where the principal ray of the light beam from the center of the image display element 15 is totally reflected on one of the surface 121 and the surface 122 of the transparent substrate 12. It arrange | positions in the position which opposes on the other surface of the transparent substrate 22. FIG. In the present embodiment, the light shielding portion 125 a is disposed at a position facing the position Pa on the other surface 121 of the transparent substrate 22 with respect to the position Pa where the principal ray described above is totally reflected on the surface 122. In addition, the light shielding portion 125 b is disposed on the other surface 122 of the transparent substrate 22 at a position facing the position Pb with respect to the position Pb where the principal ray is totally reflected on the surface 121. Further, the light shielding portion 125c is disposed on the other surface 121 of the transparent substrate 22 at a position facing the position Pc with respect to the position Pc at which the principal ray is totally reflected on the surface 122.

  FIG. 3B shows a view of the transparent substrate 12 cut in S1 of FIG. 3A and viewed from the direction of the arrow a. In FIG. 3B, the shaded portion is a portion where the shape of the light shielding portion 125a is projected. As shown by the shaded portion in FIG. 3B, the light shielding portion 125a has a rectangular shape in the cross section taken along S1 in FIG. 3A. Further, the area of the light shielding portion 125a on this surface (the area of the shaded portion) is less than or equal to half the cross-sectional area of the entire transparent substrate 12. In addition, the cross section by S1 of FIG. 3A is a cross section containing the position Pa and substantially perpendicular to the longitudinal direction of the transparent substrate 12. FIG. The light shielding part 125b and the light shielding part 125c have the same shape in the same cross section.

  A multilayer film that reflects the dominant wavelength of the light beam from the image display element 15 is formed on the light shielding surfaces of the light shielding portions 125a to 125c. The formation of the light shielding portions 125a to 125c is realized by forming a groove from the outside of the transparent substrate 12 and forming the above-described multilayer film in the groove. Alternatively, the transparent substrate 12 may be cut once to form a light shielding surface inside, and then bonded together.

Unnecessary reflected light generated in the transparent substrate 12 can be reflected and removed by the light shielding portions 125a to 125c formed in this way. Accordingly, it is possible to prevent unnecessary reflected light from becoming ghost, glare, and the like and degrading the image quality of the image observed by the observer.
As described above, according to the first embodiment, the image display means including the image display element and the first surface and the second surface that are substantially parallel to each other, and transparent that propagates the light flux from the image display means. A substrate and a combiner element that is formed in the transparent substrate and superimposes external light and the light beam from the image display means, and the transparent substrate has a light shielding portion having a light shielding surface substantially perpendicular to the longitudinal direction of the transparent substrate. Have. Therefore, unnecessary reflected light can be removed, so that deterioration in image quality can be suppressed in the wearable display device. In addition, an effect of reducing eye fatigue felt by an observer can be expected due to ghosts and glare caused by unnecessary reflected light.

Further, according to the first embodiment, the transparent substrate propagates the light flux from the image display means by totally reflecting the first surface and the second surface. In a small wearable display device, the light flux from the image display means can be efficiently propagated and guided to the observation eye.
Further, according to the first embodiment, the light shielding portion has a center at the first position where the chief ray of the light beam from the center of the image display element is totally reflected on the first surface or the second surface. , Arranged on a second position opposite to the first position on the other surface. Therefore, it is possible to prevent the main light flux from being erroneously removed while efficiently removing unnecessary reflected light.

Further, according to the first embodiment, the light shielding portion includes the first position, has a rectangular shape in a cross section substantially perpendicular to the longitudinal direction of the transparent substrate, and the area thereof is the area of the transparent substrate in the cross section described above. Less than half. Therefore, it is possible to prevent the main light flux from being erroneously removed while efficiently removing unnecessary reflected light.
According to the first embodiment, the light shielding surface of the light shielding unit reflects the dominant wavelength of the light beam from the image display means. Therefore, unnecessary reflected light can be reliably removed and unnecessary reflected light can be prevented from entering the observer's eyes.

  In the first embodiment, an example in which a multilayer film that reflects the dominant wavelength of the light beam from the image display element 15 is formed on the light shielding surfaces of the light shielding portions 125a to 125c is shown. A multilayer film that absorbs the dominant wavelength of the luminous flux from the light source may be formed. Moreover, it is good also as a structure which fills the groove | channel of the light-shielding parts 125a-125c formed in the transparent substrate 12 with the substance from which the refractive index differs from the transparent substrate 12, and removes unnecessary reflected light by the difference in both refractive indexes. Alternatively, the light shielding surfaces of the light shielding portions 125a to 125c may be colored to absorb the main wavelength of the light beam from the image display element 15 and remove the reflected light. In addition, when coloring, it is good also as a structure which can control the presence or absence of intensity | strength and intensity | strength by electricity supply, and it is good also as a structure which can control the presence or absence of coloring using an inorganic substance or an organic light control substance.

In the first embodiment, as shown in FIGS. 1 and 2, the light shielding portions 125 a to 125 c are provided with light shielding surfaces configured by planes. However, as illustrated in FIG. 3C, curved surfaces (for example, You may provide the light-shielding surface comprised from a U-shaped groove | channel.
Second Embodiment
The second embodiment of the present invention will be described below with reference to the drawings.

In the second embodiment, a wearable display device having substantially the same appearance as the wearable display device 1 of the first embodiment will be described as an example. Below, illustration of the mounting | wearing type display apparatus of 2nd Embodiment is abbreviate | omitted, and it demonstrates using the code | symbol similar to 1st Embodiment.
FIG. 4 is a schematic cross-sectional view of the optical system portion of the wearable display device 1. As shown in FIG. 4, the optical system portion includes an illumination optical system 24, an image display element 25, a collimator lens 26, a transparent substrate 22, and the like. Among these, the illumination optical system 24 and the image display element 25 are housed in the same image display unit 13 as in the first embodiment. The optical member (here, the transparent substrate 22) that is disposed in front of the observation eye E and superimposes the display light beam from the image display element 25 and the external light beam from the outside is a so-called “image combiner”.

  Since the illumination optical system 24, the image display element 25, and the collimator lens 26 are the same as the illumination optical system 14, the image display element 15, and the collimator lens 16 of the first embodiment, description thereof is omitted. The transparent substrate 22 is made of an optical material that is transparent to visible light, such as glass or plastic, and is a parallel plate in which the user-side surface 221 and the non-user-side (outside) side surface 222 are parallel.

Inside the transparent substrate 22, a polarizing beam splitter 223, a quarter-wave plate 224, a concave reflecting surface 225, and a light shielding portion 226 are formed. Among these, the polarization beam splitter 223 is formed in the vicinity of the position facing the observation eye E, and its posture is inclined by a predetermined angle with respect to the surfaces 221 and 222 of the transparent substrate 22. Details of the light shielding unit 226 will be described later.
In the wearable display device 1 described above, the image display element 25 is illuminated from behind by the illumination optical system 24 and spatially modulates incident light to generate a light beam for image display (display light beam). The display light beam becomes a parallel light beam in the collimator lens 26 and is guided into the transparent substrate 22. In FIG. 4, only the chief ray of the light beam from the center of the image display element 25 is shown.

  The display light beam incident on the transparent substrate 22 is incident on the surface 221 of the transparent substrate 22 at an angle larger than the critical angle, and is totally reflected at the first position Pd. Thereafter, the display light beam passes through the polarization beam splitter 223, passes through the quarter-wave plate 224, and is reflected by the reflection surface 225. Further, since the polarization plane of the display light beam is rotated by 90 degrees by the action of the quarter wavelength plate 224, it is reflected by the polarization beam splitter 223, then exits from the surface 221 and enters a predetermined region EP outside the transparent substrate 22. To do.

When the pupil of the observation eye E is arranged at any location in the predetermined area EP, the user can observe an enlarged virtual image of the image display element 25 at infinity on the outside side. That is, the predetermined area EP functions as an exit pupil.
In addition, at least a part of the external light flux that enters the transparent substrate 22 from the outside world passes through the transparent substrate 22 and enters the exit pupil EP. Therefore, the user can observe the scenery of the outside world together with the enlarged virtual image.

  As the image display element 25, an image display element such as a reflective LCD or a self-luminous element may be used. Further, although an example using the collimator lens 26 has been shown, instead of the collimator lens 26, one or a plurality of optical surfaces having the same function as the collimator lens 26 are used for the display light flux from the image display element 25 to the transparent substrate 22. You may provide in any location of an optical path.

FIG. 4 shows an example in which the image display element 25 is arranged in the vicinity of the transparent substrate 22. However, the image display element 25 is arranged in an appropriate place away from the transparent substrate 22 and guided to the vicinity of the transparent substrate 22 by the relay optical system. You may do it. Further, an aerial image may be formed at the same position using a scanning optical system.
Next, the light shielding part 226 that is a feature of the present invention will be described. As shown in FIG. 4, the light shielding part 226 has a light shielding surface substantially perpendicular to the longitudinal direction of the transparent substrate 22. The light shielding portion 226 is centered on the other surface of the transparent substrate 22 with respect to the first position Pd where the principal ray of the light beam from the center of the image display element 25 is totally reflected on the surface 221 of the transparent substrate 22. It arrange | positions in the position which opposes on 222.

  FIG. 5A shows a view of the transparent substrate 22 cut in S2 of FIG. 4 and viewed from the direction of the arrow b. In FIG. 5A, the shaded portion is a portion where the shape of the light shielding portion 226 is projected. As shown by the shaded portion in FIG. 5A, the light shielding portion 226 is sandwiched between a curve L1 having a different radius of curvature depending on the distance from the position Pd and a straight line L2 corresponding to the surface 222 in the cross section by S2 in FIG. Have a different shape. Further, the area of the light shielding part 226 on this surface (the area of the shaded part) is less than or equal to half of the cross-sectional area of the entire transparent substrate 22. In addition, the cross section by S2 of FIG. 4 is a cross section which includes the position Pd and is substantially perpendicular to the longitudinal direction of the transparent substrate 22.

  In addition, a multilayer film that absorbs the dominant wavelength of the light beam from the image display element 15 is formed on the light shielding surface of the light shielding unit 226. The formation of the light shielding portion 226 is realized by forming a groove from the outside of the transparent substrate 22 and forming the above-described multilayer film in the groove. Alternatively, the transparent substrate 22 may be cut once to form a light shielding surface inside, and then bonded together.

The light-shielding portion 226 formed in this way can absorb and prevent unnecessary reflected light generated in the transparent substrate 22 (antireflection). Accordingly, it is possible to prevent unnecessary reflected light from becoming ghost, glare, and the like and degrading the image quality of the image observed by the observer.
As described above, according to the second embodiment, the same effect as that of the first embodiment can be obtained.

  Further, according to the second embodiment, the light-shielding portion includes a first position, a curve having a radius of curvature that varies depending on the distance from the first position, in a cross section substantially perpendicular to the longitudinal direction of the transparent substrate. It has a shape sandwiched between a straight line corresponding to the other surface of the transparent substrate, and its area is not more than half of the area of the transparent substrate in the cross section described above. Therefore, it is possible to prevent the main light flux from being erroneously removed while efficiently removing unnecessary reflected light.

According to the second embodiment, the light shielding surface of the light shielding part absorbs the main wavelength of the light beam from the image display means. Therefore, unnecessary reflected light can be reliably removed and unnecessary reflected light can be prevented from entering the observer's eyes.
In the second embodiment, an example in which a multilayer film that absorbs the main wavelength of the light beam from the image display element 25 is formed on the light shielding surface of the light shielding unit 226 is described. A multilayer film that reflects the dominant wavelength of the light beam may be formed. Moreover, it is good also as a structure which fills the groove | channel of the light-shielding part 226 formed in the transparent substrate 22 with the substance from which the refractive index differs from the transparent substrate 22, and removes unnecessary reflected light by the difference in both refractive indexes. Alternatively, the light shielding surface of the light shielding unit 226 may be colored to absorb the main wavelength of the light beam from the image display element 25 and remove the reflected light. In addition, when coloring, it is good also as a structure which can control the presence or absence of intensity | strength and intensity | strength by electricity supply, and it is good also as a structure which can control the presence or absence of coloring using an inorganic substance or an organic light control substance.

In the second embodiment, as shown in FIG. 4, the example in which the light shielding unit 226 includes a light shielding surface including a flat surface is illustrated. However, as illustrated in FIG. 5B, the light shielding unit 226 includes a light shielding surface including a curved surface. May be. Moreover, as shown to FIG. 5C, you may arrange | position with inclination. The same applies to the light shielding portions 125a to 125c of the first embodiment.
In each of the above embodiments, the case where the light flux from the image display element propagates by being totally reflected on the surfaces (121, 122, 221, 222) of the transparent substrate and is guided in the direction of the observation eye E is taken as an example. As described above, the present invention can be similarly applied to the case where the light is guided in the direction of the observation eye E without reflection, and unnecessary reflected light can be removed. Further, the number of total reflections is not limited to the example of this embodiment. Moreover, when it has a some light shielding part, the shape of each light shielding part, a light shielding substance, etc. may be the same, and may differ.

  In each of the above-described embodiments, the description has been given using a glasses-type display as an example of the wearable display device, but the configuration of the wearable display device is not limited to this configuration example.

1 is an external view of a wearable display device 1 of a first embodiment. It is a schematic cross section of the optical system part of the mounting | wearing type display apparatus 1 of 1st Embodiment. It is a figure explaining the light shielding parts 125a-125c. It is a schematic cross section of the optical system part of the mounting | wearing type display apparatus 1 of 2nd Embodiment. It is a figure explaining the light shielding part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Wearable display apparatus, 11 ... Frame, 12.22 ... Transparent substrate, 13 ... Image display part, 15.25 ... Image display element, 125a-c.226 ... Shading part

Claims (7)

Image display means comprising an image display element;
A transparent substrate having a first surface and a second surface that are substantially parallel and propagating a light beam from the image display means;
A combiner element that is formed in the transparent substrate and superimposes external light and light flux from the image display means;
The said transparent substrate has a light-shielding part provided with the light-shielding surface substantially perpendicular | vertical to the longitudinal direction of the said transparent substrate. The mounting type display apparatus characterized by the above-mentioned. The wearable display device according to claim 1,
The mountable display device, wherein the transparent substrate propagates the light flux from the image display means by being totally reflected at least once in at least one of the first surface and the second surface. The wearable display device according to claim 2,
The light-shielding portion has a center on the other surface with respect to a first position where a principal ray of a light beam from the center of the image display element is totally reflected on the first surface or the second surface. The wearable display device is disposed at a second position opposite to the first position. The wearable display device according to claim 3,
The light-shielding portion includes the first position and has a rectangular shape in a cross section substantially perpendicular to the longitudinal direction of the transparent substrate, and the area thereof is not more than half of the area of the transparent substrate in the cross section. Wearable display device. The wearable display device according to claim 3,
The light-shielding portion includes the first position, and corresponds to a curve having a radius of curvature that varies depending on a distance from the first position and the other surface in a cross section substantially perpendicular to the longitudinal direction of the transparent substrate. The wearable display device is characterized in that it has a shape sandwiched between straight lines, and its area is half or less of the area of the transparent substrate in the cross section. The wearable display device according to any one of claims 1 to 5,
The light-shielding surface of the light-shielding part absorbs a dominant wavelength of a light beam from the image display means. The wearable display device according to any one of claims 1 to 5,
The light-shielding surface of the light-shielding part reflects a dominant wavelength of a light beam from the image display means.

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