JPH11326817A - Scanning type video observing optical system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a scanning type video observing optical system having a constitution permitting to obtain a sufficient pupil diameter and a viewing angle, and permitting high speed scanning by breaking off a contradictory relationship between a required amplitude and a size in the scanning means. SOLUTION: This scanning type video observing system is provided with a 1st scanning means for scanning with a luminous flux in the 1st direction, a 2nd scanning means for scanning with the luminous flux in the 2nd direction, an observing optical system 6 enabling the luminous flux scanned by the 1st and 2nd scanning means to be guided into pupils 7 of an observer and to be observed, and the 1st scanning means 3 and the pupils 7 are about conjugate with each other in the 1st cross-section parallel to the 1st direction and the optical axis, the 2nd scanning means 4 and the pupils 7 are about conjugate with each other in the 2nd cross-section parallel to the 2nd direction and the optical axis, and wherein it is provided with at least either a 1st luminous flux diffusing member for diffusing the luminous flux in the 1st direction which is almost aligned or almost conjugate with an image plane in the 1st cross-section, or a 2nd luminous flux diffusing member for diffusing the luminous flux in the 2nd direction which is almost aligned or almost conjugate with the image plane in the 2nd cross-section.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for scanning a light beam emitted from a light source, which is used in, for example, a head-up display or a head-mounted display, to guide the light beam to an observer's pupil, and to utilize an afterimage phenomenon of the observer. The present invention relates to a scanning image observation optical system that provides an image to an observer.

[0002]

2. Description of the Related Art FIG. 12 shows a configuration diagram of a conventional general scanning type image observation optical system. The light beam emitted from the light source 1 is modulated in light intensity by the modulator 2 and is incident on the first scanning mirror 3. The first scanning mirror 3 has a rotating shaft 3a.
, And is rotatably vibrated at a predetermined amplitude and frequency. Due to this rotational vibration, the incident light flux is reflected and simultaneously scanned in the first scanning direction.

The light beam scanned by the first scanning mirror 3 enters the second scanning mirror 4. The second scanning mirror 4 has a rotation axis 4a perpendicular to the rotation axis 3a of the first scanning mirror 3, and vibrates at a predetermined amplitude and frequency. Due to the rotational vibration, the incident light beam is reflected and simultaneously scanned in the second scanning direction. In this optical system, the first scanning direction and the second scanning direction are perpendicular to each other.

Light beams scanned by the first and second scanning mirrors 3 and 4 are reflected by the semi-transmissive surface 5 and enter the eyepiece 6. One surface of the eyepiece 6 is a reflection surface 6a, and turns the light flux back to the semi-transmission surface 5 again. The folded light beam passes through the semi-transmissive surface 5 and is provided to the pupil 7 of the observer.
Then, the image is observed by the observer due to the afterimage phenomenon.

According to such an image observation optical system, since a two-dimensional display element such as a liquid crystal display element is not used, a high-definition image can be provided regardless of the number of pixels of the display element.

[0006]

In the above-described image observation optical system, the viewing angle at which an image can be observed and the exit pupil diameter which leads to the viewer's visibility are closely related to the amplitude and size of the scanning member. Have a relationship. Scanning member 26
This will be described with reference to FIGS. 13 and 14. FIG. 13, FIG.
Numeral 4 is a cross-sectional view in which the optical axis of the image observation optical system is represented by a straight line, and each component is arranged on the straight line for convenience sake, and a member for reflecting a light beam (an eyepiece having a scanning mirror and a reflecting surface). Is also shown so that the light beam is transmitted.
Hereinafter, such a diagram is referred to as a paraxial arrangement diagram in this specification.

FIGS. 13 and 14 are cross-sectional views taken on a plane parallel to the scanning direction of the scanning member 26. The components include the modulator 2, the scanning member 26, the eyepiece 6, and the scanning member 26. FIG. 2 is a simplified diagram illustrating only a light collecting optical system 27 for collecting light. The scanning member 26 is arranged at a position conjugate to the pupil 7 in order to make the configuration as small as possible.

First, the relationship between the viewing angle and the required amplitude of the scanning member 26 will be described with reference to FIGS. The viewing angle is the maximum inclination of the light beam with respect to the pupil. FIG.
In (a), the viewing angle is denoted by a ₀ , and the required amplitude of the scanning member 26 corresponding to the viewing angle a ₀ is denoted by a ′ ₀ . If the viewing angle and a ₁ is a ₀ <a _1, a ₀ <a _'1' a true for ₁ 'scan angle a as can be seen FIG. 13 (b).
That is, as the viewing angle increases, the scanning member 2
The required amplitude of 6 also increases.

Next, the relationship between the exit pupil diameter and the size of the scanning member 26 will be described with reference to FIGS. FIG.
(A), the exit pupil diameter shown in d _0, indicates the length of the cross-sectional direction of the scanning member 26 necessary for obtaining a light beam of the exit pupil diameter d ₀ at d _'0. If the exit pupil diameter and d ₁ is d ₀ <d _{1, 0} 'd also _1' sectional direction of the length d of the scanning member 26 as can be seen FIG. 14 (b) <d _'1 and Become. That is, as the diameter of the exit pupil increases, the size of the scanning member 26 also increases.

The amplitude and the size of the scanning member 26 are also closely related. This relationship will be described with reference to FIG. FIG. 15 is a simplified paraxial arrangement diagram of a conventional image observation optical system, similar to FIGS. 13 and 14. FIG. 15 (a)
Is that the scanning member 26 is conjugate to the pupil 7 and the imaging magnification is equal, that is, the distance from the pupil 7 to the eyepiece 6 is L,
If the distance from the eyepiece 6 to the eyepiece 6 is L ', L / L' = 1
It is a figure showing the case where it becomes. In this case, the required amplitude a 'and the required length d' in the cross-sectional direction of the scanning member 26 are the same as the viewing angle a and the exit pupil diameter d, respectively.

FIG. 15B is a diagram showing a case where the scanning member 26 is conjugate to the pupil 7 and the image forming magnification is equal to or less than one, that is, L / L '<1. In this case, as can be seen from the drawing, the required amplitude a ′ of the scanning member 26 is smaller than the viewing angle a, but the required length d ′ of the scanning member 26 in the cross-sectional direction.
Is larger than the exit pupil diameter d. Although not shown, when the imaging magnification is equal to or greater than 1 ×, the required size of the scanning member 26 is reduced, but the required amplitude is increased. That is, the required amplitude and size of the scanning member 26 are completely opposite.

As described above, when the viewing angle is increased and the pupil diameter is increased, both the required amplitude and size of the scanning member increase, making it difficult to perform high-speed scanning. Further, in a conventional optical system having a configuration having a certain viewing angle and a pupil diameter, the required amplitude and the size of the scanning member 26 have a contradictory relationship as described above. Is impossible.

In view of the above problems, the present invention has a configuration in which a sufficient pupil diameter and viewing angle can be obtained, and high-speed scanning can be performed by cutting off the reciprocal relationship between required amplitude and size in the scanning means. An object of the present invention is to provide a scanning image observation optical system.

[0014]

In order to achieve the above object, the invention according to claim 1 comprises a light source for generating a light beam;
Intensity modulation means for modulating the intensity of the light beam, first scanning means for scanning the light beam in a first direction with respect to the optical axis, and a second direction different from the first direction with respect to the light axis with respect to the optical axis A scanning type image observation optical system comprising: a second scanning unit for scanning the image at a right angle; and an observation optical system for guiding a light beam scanned by the first and second scanning units to a pupil of an observer to enable observation. The first scanning means is disposed at a position substantially conjugate with the pupil position of the observer in a first section parallel to the optical axis and the first direction, and the second scanning means is connected to the optical axis and the second direction. The optical system is arranged at a position substantially conjugate with the pupil position of the observer in a second section parallel to the direction, and an image for the observer to observe is formed on the first section by the observation optical system. Position is the first image plane,
Assuming that an optical position formed on the second cross section is a second image plane, it is disposed near the first image plane or at a position substantially conjugate with the first image plane in the first cross section. A first light beam one-dimensional diffusing member for diffusing the light beam in a first direction, and a first light beam one-dimensional diffusing member disposed near the second image surface or at a position substantially conjugate with the second image surface in the second cross section; A configuration is provided that includes at least one of a second light flux one-dimensional diffusion member that diffuses light in the second direction.

The arrangement position of the scanning member (scanning means) can be made smaller as it is closer to a position conjugate with the pupil.
This will be described with reference to FIG. FIG.
Is a paraxial layout of a simple optical system including a pupil 7, an eyepiece 6, an image plane 15, and a scanning member 26. In the pupil 7, it is assumed that a light beam having a certain pupil diameter d is given through the eyepiece 6. When the scanning member 26 that scans the light beam is disposed at a position P1 conjugate with the pupil 7, the scanning member 26 can have the smallest configuration. As the position deviates from the conjugate position P1, the width of the light beam to be scanned becomes wider, and a large configuration is required. For example, at a position P2 shifted from the conjugate position P1,
It is necessary to dispose a scanning member 26 larger than the conjugate position P1.

In the above arrangement, the first scanning means is provided at a position substantially conjugate with the pupil position of the observer on the first section, and the second scanning means is provided on the observer at the second section. Is located at a position substantially conjugate with the pupil position of.
That is, the first scanning unit can be configured to be the shortest in terms of the length of the side on the first cross section. The second scanning means may be configured to be the shortest in terms of the length of the side on the second cross section. FIG. 17 shows an example of a scanning member that performs scanning by rotational vibration.

The scanning member 26 scans by rotating and vibrating in the direction of arrow 28 about the axis 26a as a rotation center axis, and reflecting while deflecting a light beam on the scanning surface 26b. At this time, the moment of the rotational vibration becomes smaller as the scanning surface 26b becomes smaller, and high-speed vibration becomes possible. However, b ₁
The effect of the length of gives the moment much larger than the b _2, b _1, even if b ₂ is without both short moment of rotational vibration alone b ₁ is short enough small.

When the scanning member 26 is the first scanning means, b ₁ is the length on the first section. In the case of the second scanning means, it is the length on the second section. That is, the first scanning means can be configured to be short with respect to the length on the first cross section, and the second scanning means can be configured to be short with respect to the length on the second cross section. With such a configuration, the moment of the rotational vibration of each scanning unit can be extremely reduced.

Further, the above structure is arranged near the first image plane or near the position substantially conjugate to the first image plane in the first cross section, and the first structure for diffusing the light beam in the first direction. A light beam one-dimensional diffusing member, and a second light beam 1 disposed near the second image surface or near a position substantially conjugate to the second image surface in the second cross section and diffusing the light beam in the second direction. This is a configuration including at least one of the dimensional diffusion members.

With such a configuration, the pupil diameter can be increased without increasing the size of the scanning means. This principle will be described with reference to FIG. FIGS. 18 (a) and 18 (b)
FIG. 2 is a simple paraxial arrangement diagram showing only an image plane 15, an eyepiece 6, and a pupil 7; The pupil diameter d increases as the divergence angle c of the light beam on the image plane 15 increases. As can be seen from FIG. 18B, if c ′> c, then d ′> d.

As described above, by disposing the diffusing member in the vicinity of the image plane or in the vicinity of the position substantially conjugate with the image plane, it is possible to diffuse the light beam into a light beam having a large divergence angle and to enlarge the pupil diameter. it can.

According to a second aspect of the present invention, in the scanning image observation optical system according to the first aspect, the inclination of the first one-dimensional diffusing member with respect to the optical axis of the diffusing surface is substantially equal to that of the first image plane. The second one-dimensional diffusing member is arranged so that the inclination of the diffusing surface with respect to the optical axis substantially coincides with the second image plane. Since the one-dimensional light beam diffusion member optically coincides with the image plane on which an image to be observed by the observer is formed, the inclination of the observed image is suppressed by adopting such a configuration.

According to a third aspect of the present invention, there is provided a scanning image observation optical system according to the first or second aspect, wherein
The one-dimensional diffusion member is a diffractive element. As described above, by using diffraction for one-dimensional diffusion, the diffusion direction, the diffusion angle, and the like can be accurately controlled.

[0024] The invention described in claim 4 is the first to third aspects of the present invention.
The scanning image observation optical system according to any of the above,
The one-dimensional diffusing member is formed and provided on the second scanning means. According to a fifth aspect of the present invention, in the scanning type image observation optical system according to any one of the first to fourth aspects, a second one-dimensional diffusing member is formed and provided on the first scanning means. Configuration.

As described above, the number of components can be reduced by forming the diffusion member and the scanning means by one member.

According to a sixth aspect of the present invention, there is provided the image observation optical system according to the fourth or fifth aspect, wherein one of the first and second scanning means is provided on the optically rearward scanning means. When a diffusing member is formed, the light beam enters the scanning unit at a vertical angle.

The scanning means provided with the diffusion member optically coincides with the image plane. When the scanning unit is disposed optically rearward, it is necessary that the light beam be incident at a perpendicular angle in order to suppress the inclination of the image plane.

[0028]

Embodiments of the present invention will be described below with reference to the drawings. The same components as those in the drawings used in the conventional technology are denoted by the same reference numerals. <First Embodiment> FIG. 1 shows a paraxial layout of a scanning image observation optical system according to a first embodiment. Reference numerals 3 and 4 denote a first scanning member (first scanning means) and a second scanning member (second scanning means) for scanning the light beam by rotational vibration, respectively. The first scanning member 3 scans the light beam in a first direction perpendicular to the optical axis. The second scanning member 4 scans the light beam in a second direction perpendicular to the optical axis and the first direction.

FIG. 1A is a sectional view on a plane (first section) parallel to the first direction including the optical axis. FIG.
(B) is a sectional view on a plane (second section) parallel to the second direction including the optical axis.

The light beam emitted from the light source 1 is intensity-modulated by a modulator (intensity modulation means) 2 and the first scanning member 3
Incident on. The light beam is scanned in the first direction by the first scanning member 3 and is incident on the second light beam one-dimensional diffusion member 13.

The second light flux one-dimensional diffusion member 13 diffuses the light flux only in the second direction. The first direction does not affect the light beam. The light flux incident on the second light flux one-dimensional one-dimensional diffusion member 13 is diffused only in the second direction at a predetermined angle. The light beam diffused here enters the second scanning member 4. The light beam incident on the second scanning member 4 is scanned in the second direction, and is incident on the cylinder lens 14.

The cylinder lens 14 is an anamorphic optical system having a refractive power only in the second direction, and has a second light flux one-dimensional diffusing member 13 in a second section.
Has a function of making the image plane 15 of the eyepiece 6 conjugate with the image plane 15. Therefore, the light beam diffused only in the second direction by the second light beam one-dimensional diffusion member 13 is applied to the image plane 1 of the eyepiece 6.
5 is collected.

The luminous flux is supplied to a first luminous flux one-dimensional diffusing member 12 disposed at the position of the image plane 15 via a cylinder lens 14. The first light beam one-dimensional diffusing member 12 diffuses the light beam only in the first direction, and does not affect the light beam in the second direction. The light beam incident on the first light beam one-dimensional diffusion member 12 is diffused only in the first direction at a predetermined angle. The light beam formed on the image plane 15 enters the pupil 7 of the observer through the eyepiece 6 and is observed.

In the above configuration, the first scanning member 3 and the pupil 7 are conjugated in the first cross section so that the scanning members 3 and 4 are small, and the second scanning member 4 and the pupil 7 are connected in the second cross section. Each is arranged so as to be conjugate. That is, each of the scanning members 3 and 4 is configured so that the length of the side in the direction that greatly affects the moment of the rotational vibration can be reduced. In addition, since the pupil diameter is enlarged using the light flux one-dimensional diffusion member 12 or 13 in each of the first direction and the second direction, the pupil diameter is increased by increasing the size of the scanning members 3 and 4. That need not be achieved,
The conflicting relationship between the size and the amplitude of the scanning member as described above is cut off.

In this embodiment, the imaging magnification of the first and second scanning members 3 and 4 with respect to the pupil is equal to or less than the same magnification (see FIG. 1), and the required amplitude is reduced as compared with the viewing angle. ,
In addition, since the reciprocal relationship between the size of the scanning member and the amplitude is broken, the sizes of the scanning members 3 and 4 are configured to be small.

Here, the scanning required for each of the scanning members 3 and 4 when a specific image is displayed will be briefly described with reference to FIG. It is assumed that a high-definition image is displayed. The aspect ratio of a high-definition video is 16: 9, the number of frames that must be displayed in one second is 60 frames, and the required number of horizontal scanning lines is about 1,000.

The horizontal scanning frequency is obtained by multiplying the number of horizontal scanning lines × the number of horizontal scanning lines.
It is 60 kHz because it is given by the number of frames, and the vertical scanning frequency is 60 Hz because the number of frames is sufficient. As described above, the required scanning frequency is higher in the horizontal direction than in the vertical direction, and the required scanning angle is larger in the horizontal direction, so that scanning in the horizontal direction requires overwhelmingly high-speed scanning. I do. Generally, horizontal scanning is called main scanning and vertical scanning is called sub-scanning.

In the present embodiment, since the second scanning member 4 is disposed optically behind the first scanning member 3, the second scanning member 4 needs to have a size covering the scanning angle of the first scanning member 3. It is necessary to make the configuration larger than that of the first scanning member 3. Therefore, by using the first scanning member 3 that can be configured to be small in the main scanning, a configuration is provided in which the effects of the present invention are more exhibited.

<Second Embodiment> FIG. 3 shows a paraxial layout of a scanning image observation optical system according to a second embodiment. FIG.
FIGS. 1 (a) and 1 (b) show FIGS. 1 (a) and 1 (b) of the first embodiment.
FIG. Only different points from the first embodiment will be described. In the present embodiment, the first scanning member 3,
Second light beam one-dimensional diffusing member 1 on second scanning member 4
3. The first light flux one-dimensional diffusion member 12 is formed.
Reference numeral 17 denotes an anamorphic lens having different optical refractive powers in the first direction and the second direction.

Reference numeral 14 denotes a cylinder lens having a refractive power only in a first direction, and reference numeral 16 denotes a cylinder lens having a refractive power only in a second direction. The second scanning member 4 (the first luminous flux one-dimensional diffusion member 1) is formed by the anamorphic lens 17 and the cylinder lenses 14 and 16.
2) The image plane 15 in the first cross section and the first scanning member 3 (the second light flux one-dimensional diffusion member 13) are substantially conjugate with the image plane 15 in the second cross section. The luminous flux diffused at a predetermined angle by the one-dimensional diffusion members 12 and 13 forms an image on an image plane 15.

According to the configuration of this embodiment, the same effect as that of the first embodiment can be obtained by the configuration in which the one-dimensional light diffusion member is formed on the scanning member.

<Third Embodiment> FIG. 4 shows a paraxial arrangement of a scanning image observation optical system according to a third embodiment. FIG.
FIGS. 1 (a) and 1 (b) show FIGS. 1 (a) and 1 (b) of the first embodiment.
FIG. Only different points from the first embodiment will be described. In this embodiment, the observation optical system includes two anamorphic lenses 11a and 11b having different refractive powers in the first direction and the second direction.

The optical position where an image to be observed by an observer is formed on the first section by the observation optical system is defined as a first image plane, and the optical position formed on the second section is defined as a second position. , The first image plane and the second image plane do not coincide with each other due to the anamorphic observation optical system. The respective positions are indicated by 15a and 15b on the drawing. In the first and second embodiments, since the two image planes coincide with each other, the first and second image planes are not distinguished. Reference numeral 18 denotes a condenser lens.

In this embodiment, the first image plane 15a
And the conjugate plane with the pupil 7 in the second cross section is matched, so that the first light beam one-dimensional diffusing member is placed on the second scanning member 4 disposed at the conjugate position with the pupil 7 in the second cross section. 12 can be arranged. First light flux one-dimensional member 12
In the second scanning member 4 integrally formed, the diffusion of the light beam in the first direction and the scanning in the second direction are performed.

Further, by disposing the first scanning member 3 arranged at a conjugate position with the pupil 7 on the first section, at a position conjugate with the second image plane on the second section, Second light beam one-dimensional diffusing member 1 on first scanning member 3
3 can be arranged integrally. In the first scanning member 3 in which the second light flux one-dimensional diffusion member 13 is integrally formed,
Diffusion of the light beam in the second direction and scanning in the first direction are performed. With such an arrangement, the first,
The same effects as those of the second embodiment can be obtained, the number of parts can be reduced as compared with the configurations of the first and second embodiments, and the conjugate relationship is simplified, so that the overall length is compact. It is possible to take a configuration.

In the configuration of the second and third embodiments,
Since the second scanning member 4 is arranged at a position which is coincident with or conjugated with the image plane in the first section, the size of the second scanning member 4 is large. However, as described above, the sub-scan does not require a very high-speed scan, so that
There is no problem if the scanning member 4 is used for sub-scanning.

FIG. 5 shows a specific configuration example of the scanning image observation optical system according to the third embodiment shown in FIG. FIG. 5 is a configuration diagram in the second section. The scanning members 3 and 4 are constituted by reflection mirrors supported on a rotating shaft. The light beam scanned by the first scanning member 3 is divided into two reflection mirrors 19.
After being reflected by a and 19b, the light enters the condenser lens 18. 21 is a translucent surface 20;
This is a prism in which the anamorphic lens 11b is configured to face the second scanning member 4. 22 is
This is a prism having a semi-transmissive surface 22a.

Anamorphic lens (eyepiece) 1
In 1a, one surface 11a 'is a back reflection surface. In the present configuration example, the eyepiece lens 11a is arranged on the reflection side of the semi-transmission surface 22a. However, the eyepiece lens 11a is arranged on the transmission side (below the drawing) of the semi-transmission surface 22a and reflected by the eyepiece lens 11a. It is also possible to adopt a configuration in which the emitted light beam is reflected by the semi-transmissive surface 22a and guided to the pupil 7. In this case, the semi-transmissive surface 22a is configured to function as a combiner that superimposes a light beam from the outside (front of the pupil, right side of the drawing) and a light beam for image display, so that the display is overlapped with the outside, for example, a landscape. It becomes a see-through type observation optical system that can be observed.

Next, how the light beam is diffused by the light beam one-dimensional diffusing members 12 and 13 will be described with reference to FIG. FIG.
FIG. 6 is a perspective view schematically showing a state of a part of a light beam near the second scanning member 4 in the configuration example shown in FIG. The second scanning member 4 scans the incident light beam in the second direction by rotating and vibrating about the rotation axis 4a in the direction of arrow 24. The fan-shaped luminous flux 23 diffused in the second direction by the second luminous flux one-dimensional diffusing member 13 integrally disposed on the first scanning member 3 is incident on the semi-transmissive surface 20 and is reflected as the second luminous flux.
Vertically incident on the scanning member 4.

A first light beam one-dimensional diffusing member 12 is integrally arranged on the second scanning member 4.
Here, the light beam 23 diffused only in the second direction incident on the light beam is diffused in the first direction. The light beam emitted from the second scanning member 4 is a light beam diffused in both the first and second directions.

FIG. 7 shows an example of the configuration of the light flux one-dimensional diffusing members 12 and 13. This configuration example is an example using a diffraction grating in which groups having a maximum height of about 0.35 μm and a pitch of about 30 μm are arranged. FIG. 7 is a partially enlarged view of the diffraction grating. FIG. 8 schematically shows a light beam diffusion state obtained when a light beam is incident on this diffraction grating. The size of the circle in the figure indicates the light intensity ratio, and the line type of the circle indicates the wavelength of the light. In the drawing, the diffusion state of green (G), blue (B), and red (R) is shown as a representative wavelength. The line types of the circles of G, R, and B are solid lines, respectively.
A dotted line and a dashed line are used. The lengths and directions of A and B in FIG. 8 correspond to the lengths and directions of A and B in FIG.

As can be seen from the figure, it can be seen that the light beam is diffused only in one-dimensional direction, and furthermore, it is diffused almost uniformly at each wavelength. As described above, when the light beam is diffused using the diffraction grating, a desired diffusion can be obtained with high accuracy.

The scanning image observation optical systems according to the first to third embodiments for carrying out the present invention have been described above, but the scanning image observation optical system according to the present invention is not limited to these configurations. In the above description, two light flux one-dimensional diffusing members for diffusing the light flux in the first direction and the second direction are arranged, but there is no problem even if only one of them is arranged.
The pupil diameter can be enlarged only in a desired direction by selecting the diffusion member to be arranged.

Hereinafter, when a scanning image observation optical system having a configuration different from those of the first to third embodiments is constructed,
Two important points when specifically configuring the optical system according to the third embodiment will be described.

One is that the scanning member and the diffusion member whose scanning direction and diffusion direction coincide with each other cannot be integrally arranged.
As shown in FIG. 9, the first light beam one-dimensional diffusing member 12
And the first scanning member (reflection surface) 3 are integrated, the direction in which the light beam is diffused is the same as the direction in which the light beam is scanned, so that the light beam deflected by scanning and the diffused light beam overlap.

For example, when the scanning member 3 is in the state of 3a, the reflected light of the incident light 8 is 8a. At this time, it is assumed that the reflected light beam 8a is diffused, for example, in the range of 9a by the first light beam one-dimensional diffusion member 12 diffusing the light beam at a predetermined angle. On the other hand, when the scanning member 3 is in the state of 3b, the reflected light beam of the incident light beam 8 becomes 8b, and the reflected light beam 8
b is diffused into the range of 9b.

Since the scanning direction and the diffusion direction are the same,
As can be seen from the drawing, an overlapping range 9ab where the diffusion ranges 9a and 9b overlap occurs. Since the light flux in the overlapping range 9ab becomes a ghost and is observed by the observer, such an integrated arrangement is impossible. Similarly, the second scanning member 4 and the second light flux one-dimensional diffusion member 13 whose scanning direction and diffusion direction are the same cannot be integrally arranged.

Another important point is that, when the light beam one-dimensionally diffusing member arranged optically rearward is arranged integrally with the scanning member, the light beam is configured to be vertically incident on this member. There is a need. The second embodiment will be described as an example. In the case of the second embodiment, the first light beam one-dimensional diffusion member 12 optically arranged rearward is integrated with the second scanning member 4. It is assumed that the second scanning member 4 is configured by a reflection mirror that rotates and vibrates about the rotation axis 4a.

The first one-dimensional light diffusing member 12 disposed optically behind has already been one-dimensionally diffused by the second one-dimensional light diffusing member 13 at the optical front thereof. The light flux enters while changing the inclination.
When this light beam is made incident on the second scanning member 4, the light beam always hits the scanning surface off the rotation axis 4 a of the second scanning member 4 due to the spread of the light beam or the inclination of the light beam.

As shown in FIG. 10, when the light beam is made incident on the second scanning means 4 at an angle other than perpendicular, the optical distance between the image plane 15 and the rotation axis 4a of the scanning member 4 is perpendicular to the optical axis. A shift occurs, and eventually the image plane 15 and the image forming plane 15 'shift. Due to this shift, the observation image is observed obliquely in the direction of the optical axis, causing a problem.

In order to prevent this, it is necessary for the light beam to enter the second scanning means 4 vertically. FIG.
As shown in (2), when the light beam is incident perpendicularly by providing the transmission surface 25, the optical distance between the diffusion surface of the diffusion member 12 and the image surface 15 becomes equivalent at any point on the diffusion surface, and the imaging surface 1
5 ′ and the image plane 15 can be matched.

[0062]

According to the scanning type image observation optical system of the present invention, both of the two scanning members can be made small. Further, since the enlargement of the pupil diameter is achieved by using the diffusion member, the conflicting relationship between the required amplitude and the size of the scanning member can be broken. Therefore, even if the required amplitude is reduced, it is not necessary to increase the size of the scanning member.

According to such a configuration, high-speed scanning, that is, display of a high-definition image can be performed with a small scanning member. Further, since the required amplitude can be reduced, the range in which the viewing angle can be expanded is widened. Furthermore, since the pupil diameter can be enlarged without increasing the size of the scanning member, the range in which the pupil diameter can be enlarged is widened.

[Brief description of the drawings]

FIG. 1 is a paraxial arrangement diagram in a first section (a) and a second section (b) of a scanning image observation optical system according to a first embodiment.

FIG. 2 is an explanatory diagram in the case of displaying a high-definition video.

FIG. 3 is a paraxial layout diagram of a first cross section (a) and a second cross section (b) of the scanning image observation optical system according to the second embodiment.

FIG. 4 is a paraxial layout diagram of a first cross section (a) and a second cross section (b) of the scanning image observation optical system according to the third embodiment.

FIG. 5 is a diagram illustrating a specific configuration example of a scanning image observation optical system according to a third embodiment.

FIG. 6 is a diagram schematically showing a state of a light beam near a second scanning member on which a light beam one-dimensional diffusing member is integrally arranged.

FIG. 7 is a diagram showing a configuration example of a light flux one-dimensional diffusion member.

FIG. 8 is a view schematically showing a light beam diffusion state obtained by the light beam one-dimensional diffusion member shown in FIG. 7;

FIG. 9 is a diagram showing a state of a light beam when a scanning member and a diffusion member whose scanning direction and diffusion direction are the same are arranged integrally.

FIG. 10 shows a second example in which a light flux one-dimensional diffusion member is integrally arranged.
FIG. 4 is an explanatory diagram showing a shift between an image plane and an image forming plane when a light beam is incident on the scanning member at an angle other than perpendicular.

FIG. 11 shows a second example in which the one-dimensional light diffusing member is integrally arranged.
FIG. 4 is an explanatory diagram showing the coincidence of the image plane and the image forming plane when a light beam enters the scanning member at a vertical angle.

FIG. 12 is a configuration diagram of a conventional general scanning type image observation optical system.

FIG. 13 is a view for explaining the relationship between the viewing angle and the required amplitude of the scanning member.

FIG. 14 is a view for explaining the relationship between the exit pupil diameter and the size of the scanning member.

FIG. 15 is a diagram for explaining the relationship between the amplitude and the size of the scanning member.

FIG. 16 is a view for explaining the relationship between the arrangement position and the size of the scanning member.

FIG. 17 is a diagram illustrating an example of a scanning member.

FIG. 18 is a view for explaining the relationship between the divergence angle of the light beam on the image plane and the size of the pupil diameter.

[Explanation of symbols]

 Reference Signs List 1 light source 2 modulator 3 first scanning member 4 second scanning member 6 eyepiece 7 pupil 12 first light flux one-dimensional diffusion member 13 second light flux one-dimensional diffusion member 14 field lens 15 image plane 15a first Image plane 15b Second image plane

Claims (6)

[Claims] A light source for generating a light beam; intensity modulation means for modulating the intensity of the light beam; first scanning means for scanning the light beam in a first direction with respect to the optical axis; First
A second scanning unit that scans in a second direction different from the first direction, and an observation optical system that guides a light beam scanned by the first and second scanning units to an observer's pupil to enable observation. In the scanning type image observation optical system, the first scanning means is disposed at a position substantially conjugate with the pupil position of the observer on a first section parallel to the optical axis and the first direction. The scanning means is disposed at a position substantially conjugate with the pupil position of the observer in a second cross section parallel to the optical axis and the second direction, and an image for the observer to observe by the observation optical system is provided. The optical position formed on the first section is defined as a first image plane,
If the optical position formed in the cross section of is a second image plane, it is disposed in the vicinity of the first image plane or in a position substantially conjugate with the first image plane in the first cross section. A first light flux one-dimensional diffusing member for diffusing in a first direction with respect to the optical axis;
A second light beam one-dimensional diffusion that is disposed near the second image surface or at a position substantially conjugate to the second image surface in the second cross section and that diffuses the light beam in the second direction with respect to the optical axis; A scanning image observation optical system comprising at least one of members. 2. The first one-dimensional diffusion member is disposed such that the inclination of the diffusion surface with respect to the optical axis substantially coincides with the first image plane. 2. The scanning type image observation optical system according to claim 1, wherein an inclination of the optical axis with respect to the optical axis is arranged to substantially coincide with the second image plane. 3. The scanning image observation optical system according to claim 1, wherein the first and second one-dimensional diffusion members are diffraction elements. 4. The scanning image observation optical system according to claim 1, wherein the first one-dimensional diffusing member is provided on the second scanning means. 5. The scanning image observation optical system according to claim 1, wherein a second one-dimensional diffusing member is formed and provided on the first scanning means. 6. When a diffusing member is formed on one of the first and second scanning means which is optically disposed rearward, the light beam enters the scanning means at a vertical angle. The image observation optical system according to claim 4 or 5, wherein: