JP2003029197A - Scanning image observation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a scanning image observation device, which enables an observer to observe a bright image by an eyepiece optical system without using a two-dimensional display panel. SOLUTION: A light beam 11, emitted from a light source 3, is converted into a converged light beam by a converging optical system (collimating optical system) 4 and is made incident on a scanning optical system arranged in the vicinity of its focus. The light beam 11 reflected and deflected by the scanning optical system is made incident on a collimator lens 6 as a diffused light beam and is converted into a beam of approximately parallel rays, and is made incident on a microlens array 7, to form an image of the light source in the vicinity of its focus. When the light beam 11 scans in the scanning optical system 5, the position of an image point, formed in the microlens array 7, is scanned to form an aerial image panel 8 in the vicinity of the focus of the microlens array. The scanning optical system 5 perform two-dimensional scanning, and the aerial image paned 18 is formed in two-dimensional shape. An observer 10 will observe the image on a two-dimensionally formed aerial image panel 8 as an aerial image by an eyepiece optical system 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image observation apparatus, and in particular, a two-dimensional image is formed on the image plane of an eyepiece optical system.
The present invention relates to a scanning image observing apparatus for an observer to observe the aerial image.

[0002]

2. Description of the Related Art Conventionally, a head-mounted display device (Head Mou
A lot of nted displays (HMDs) have been proposed.

An outline of a conventional HMD optical system will be described with reference to FIG. The illumination optical system 111 illuminates the two-dimensional image display element 112. The image display element 112 is composed of a liquid crystal panel or the like, and modulates transmitted light to form a two-dimensional image. The two-dimensional image display element 112 includes the eyepiece optical system 1
It is placed in the vicinity of the focal plane of 14 and its image is observed by the eyepiece optical system 114. Observer 1
15 observes this two-dimensional image via the eyepiece optical system 114. As a conventional example, FIG. 11 shows a case where a transmission type two-dimensional image display element is used, but a reflection type two-dimensional image display element may be used in some cases.

Further, as an optical system of an HMD for forming an image without utilizing a two-dimensional image display element, US Pat.
The optical system described in Japanese Patent No. 701,132 is disclosed. FIG. 12 is a diagram showing an outline of the optical system of this conventional technique, in which the light beam from the light source 121 becomes a condensed beam by the condensing optical system 122, and the condensing optical system 122.
Is incident on the scanning optical system 123 near the focal point of. The light beam from the scanning optical system 123 enters the observer's eye 125 through the eyepiece optical system 124 and forms an image of the light source on the retina.
When the scanning optical system 123 scans the light beam, the light source image scans the retina, and the observer can observe the two-dimensional image.

[0005]

However, in the image observing system for observing an image by the conventional two-dimensional image display device, a two-dimensional display panel such as an LCD for displaying the image is required. Along with this, a two-dimensional image display element typified by an LCD is extremely expensive, and when the manufacturing cost reduction of the entire device is taken into consideration, there is a problem that the two-dimensional image display element becomes a bottleneck and it is difficult to reduce the price. It was

Further, when the two-dimensional image display element is a transmissive element, the transmissive two-dimensional image display element generally has a low transmittance, so that there is a problem that the light amount loss until reaching the observer is large. was there. Further, in the case of the method of directly forming an image of the light beam on the retina of the observer, although there is no need for a two-dimensional image display element, there is a problem that a new special optical system adapted to the scanning system used is required. .

Therefore, the present invention provides an image observation apparatus for observing a two-dimensional image formed on the image plane of an eyepiece optical system,
An object of the present invention is to provide a scanning image observation apparatus capable of observing a bright image, which can utilize a conventional HMD eyepiece optical system without using a two-dimensional display panel such as an LCD.

[0008]

In order to solve the above problems, the present invention provides a light source for emitting a light beam in an image observation apparatus for observing a two-dimensional image as an aerial image through an eyepiece optical system. A condensing optical system that condenses the emitted light beam, a scanning optical system that scans the condensed light beam, and a condensing light beam that is scanned to form an image of a light source. A lens array, and an eyepiece optical system for observing a two-dimensional image formed by sequentially forming the scanned light beam in the vicinity of the focal point of each lens of the lens array as an aerial image. .

With the above arrangement, a bright and clear image can be observed without using a two-dimensional display panel having a low transmittance such as an LCD panel.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

First, a first embodiment will be described with reference to FIG. 1A and 1B are schematic configuration diagrams of an optical system of the scanning image observation apparatus of the present invention. In FIG. 1A, a light beam 11 emitted from a light source 3 is a light beam condensed by a condensing optical system (collimating optical system) 4, and a scanning optical system 5 arranged near the focal point thereof. Incident. Light beam 11 reflected and deflected by the scanning optical system 5
Enters the collimator lens 6 as a diffused light beam. The light beam 11 becomes a substantially parallel beam by the collimator lens 6. This light beam 11 becomes a substantially parallel beam
Is a microlens array (hereinafter, M lens array) 7
Incident on. The light beam 11 is generated by the M lens array 7.
An image of the light source is formed near the focal point of the M lens array 7.

When the scanning optical system 5 scans the light beam 11 from the state of FIG. 1A, the position of the image point by the M lens array 7 is also scanned as shown in FIG. The aerial image panel 8 is formed near the focal point. The scanning optical system 5 performs two-dimensional scanning, and the aerial image panel 8 is also two-dimensionally formed. Only one cross section is shown in FIGS. 1A and 1B. The resolution of the aerial image panel 8 formed is
It depends on the number of lenses of the M lens array 7. Observer 10
Observes the formed image of the two-dimensional aerial image panel 8 by the eyepiece optical system 9 as an aerial image.

In FIGS. 1 (a) and 1 (b), the light from the light source 3 is emitted with its intensity changed by the control circuit 2 in response to the video signal 1. As the light source 3, an LED, a laser diode (LD) or the like can be used. Further, as a means for changing the intensity, a method of modulating the intensity of the light source, a method of controlling the modulation by time division by turning the light source on and off, and the like are used.

In FIGS. 1A and 1B, the control circuit 2
The light source 3 and the scanning optical system 5 are electrically connected to each other. The scanning optical system 5 is controlled by the control circuit 2 in response to the video signal 1 to deflect and scan the incident light beam 11.

Next, with reference to FIG. 2, the outline of the two-dimensional image formation in this embodiment will be briefly described. Although the optical path is actually folded back by the scanning optical system, in FIG. 2, the optical path is not folded back for the sake of simplicity. Further, the same reference numerals are given to those having the same functions as those in FIG. 1, and the description thereof will be omitted.

The light emitted from the light source 3 is condensed by the condensing optical system 4 and guided to the scanning optical system 5 as a condensed light beam. The light beam becomes a spot in the vicinity of the scanning optical system 5 and is reflected and deflected by the scanning optical system 5 in a two-dimensional direction. The light beam deflected by the scanning optical system 5 enters the collimator lens 6 and becomes a substantially parallel beam and enters the M lens array 7. The light beam incident on the M lens array 7 forms an image of the light source 3 on the image plane, and an image point train is formed on the image plane as the scanning optical system 5 scans. A two-dimensional aerial image panel 8 is formed on the image plane by modulating the intensity of the light beam in synchronization with the movement of this image point sequence. The resolution of the aerial image panel 8 matches the number of M lens arrays 7 forming the aerial image panel 8.

FIG. 3 shows an example of the scanning optical system. The scanning optical system is composed of a minute flat mirror 31 made of single crystal silicon, and the surface of the mirror has a reflectance enhanced by vapor deposition of aluminum or silver. Further, the minute flat mirror 31 is held by two torsion bars 32 and 33, which correspond to the horizontal and vertical scanning directions, respectively.
Torsional vibration. The micro flat mirror 31 is resonantly driven by an electrostatic force between an electrode (not shown) installed together with the mirror. In order to obtain a particularly flicker-free image, the scanning frequency in the vertical direction is set to 30 Hz or higher. The scanning frequency in the horizontal direction depends on the resolution of the display image and the scanning frequency in the vertical direction.

Next, with reference to FIGS. 4 and 5, the outline of the formation of the aerial image panel will be described. In addition, the same reference numerals are given to those having the same functions as those in FIG. 1, and the description thereof will be omitted. The light beam deflected by the scanning optical system 5 and collimated by the collimator lens 6 forms an image on the image plane 8 of the M lens array 7. The formed light beam has an image point sequence 5 as shown in FIG.
1 to form the aerial image panel 8 on the image plane. This eliminates the need for a two-dimensional display panel such as the LCD panel used in the conventional HMD.

Further, since the transmission type image display element is not used as the two-dimensional image display element, the light amount loss from the light source is smaller than that in the case where the transmission type two-dimensional image display element having a low transmittance is used.

Next, an example of the eyepiece optical system 9 will be described with reference to FIG. The eyepiece optical system 9 is composed of a prism, and the incident light beam is refracted by the prism surface 9a,
It is totally reflected at b. The totally reflected light is reflected by the free-form surface 9c which is a reflecting surface coated with aluminum or the like, is refracted by the prism surface 9b, and is guided toward the observer. As the eyepiece optical system 9, the optical system used in the conventional HMD can be used as it is. The optical system that can be used as the eyepiece optical system is not limited to the free-form surface prism.

In the example of FIG. 1, by appropriately selecting the focal length of the collimating lens 6, the size of the aerial image panel to be formed can be changed. Further, by changing the number of lenses of the M lens array 7, the resolution of the aerial image panel 8 formed can be changed. Conventionally, when the resolution or size is changed by using a two-dimensional display panel, it is necessary to change the two-dimensional display panel itself, but it is possible to easily cope with it by only changing the optical system.

Next, a second embodiment will be described with reference to FIG. FIG. 7 shows a schematic configuration of the second embodiment, which is different from the first embodiment only in the light source portion and the scanning optical system portion. Therefore, here, only the light source portion and the scanning optical system portion will be described. In the present embodiment, the light source 72 uses red (R), green (G), and blue (B) three-color light sources. An LED or LD is used as the light source. Modulation control corresponding to the video signal is performed on the light source of each color of RGB.

Next, the structure of the light source 72 will be described with reference to FIG. The light source 72 is a light source 72a, 72 corresponding to RGB.
b, 72c and a color combining system 81. The light beams 11a, 11b, and 11c emitted from the three-color light sources 72a, 72b, and 72c are combined by the color combining system 81, and are incident on the condensing optical system as the light beam 11. A dichroic mirror or the like can be considered as the color synthesis system.

FIG. 9 shows an example of the scanning optical system used in the second embodiment. Although illustrated as one mirror in FIG. 7, the scanning optical system 71 is actually composed of two mirrors of a horizontal scanning system 71a and a vertical scanning system 71b. The horizontal scanning system 71a is a single crystal silicon fine plane mirror, and aluminum or silver is vapor-deposited on the surface thereof. The mirror is held by a torsion bar and resonantly driven by an electrostatic force between the mirror and an electrode installed together with the mirror. The vertical scanning system 71b is, for example, a reflection scanning system such as a galvanometer mirror, and is installed such that its axial direction is orthogonal to the horizontal scanning system 71a. The above horizontal scanning system 71a and vertical scanning system 71
A scanning optical system 71 is configured by the two mirrors b. Further, the vertical scanning system 71b is driven at a frequency of 30 Hz or higher to provide a flicker-free image. The scanning frequency of the horizontal scanning system 71a depends on the scanning frequency of the vertical scanning system 71b and the image resolution.

In the example of FIG. 7, the size of the aerial image panel to be formed can be changed by properly selecting the focal length of the collimating lens 6. Further, by changing the number of lenses of the M lens array 7, the resolution of the aerial image panel to be formed can be changed.
From these, it becomes possible to deal with the change of the size and resolution of the image only by changing the optical system.

Next, a third embodiment will be described with reference to FIG. FIG. 10 shows an example of a viewfinder utilizing the present invention, which includes an eyepiece optical system 101 and a distance changing device 1.
Except for 02, it is the same as in the first and second embodiments.
Therefore, except for the eyepiece optical system 101 and the distance changing device 102, those having the same functions as those in FIG. 1 and FIG. In FIG. 10A, the eyepiece optical system 101 is not the prism as shown in FIG. 10
Observes the image on the aerial image panel 8.

Further, as shown in FIG. 10B, the collimator lens 6 and the M lens array 7 are connected to each other by a distance changing device 10
Since the size of the aerial image panel to be formed can be changed by simultaneously using 2 to move, the observation image can be easily enlarged or reduced without changing the eyepiece optical system. In this case, the resolution of the observed aerial image panel does not change.

Further, in the first to third embodiments, the collimator lens 6 and the M lens array 7 can be integrated.

[0029]

As described above, the present invention is provided with an optical system using a light beam scanning system and an M lens array,
Since a two-dimensional display panel having a low transmittance such as a CD panel is not used, a bright and clear image can be observed.

Further, since an expensive two-dimensional display panel such as an LCD panel is not required, the cost of the device can be reduced.

Furthermore, since the size of the aerial image panel to be formed can be changed by changing the distance between the scanning optical system and the M lens array, the observation image can be easily enlarged or reduced. Become.

Further, the eyepiece optical system can be shared with the one used in the conventional HMD.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of an optical system according to the first embodiment.

FIG. 3 is an explanatory diagram of a scanning optical system according to the first embodiment.

FIG. 4 is an optical path diagram of an optical system in forming an aerial image panel.

FIG. 5 is a locus diagram of image points when an aerial image panel is formed.

FIG. 6 is a sectional view of an eyepiece optical system according to the first embodiment.

FIG. 7 is a schematic configuration diagram of a second embodiment of the present invention.

FIG. 8 is an explanatory diagram of a light source according to the second embodiment.

FIG. 9 is an explanatory diagram of a scanning optical system according to a second embodiment.

FIG. 10 is a schematic configuration diagram of a third embodiment of the present invention.

FIG. 11 is a schematic configuration diagram of a conventional HMD.

FIG. 12 is a schematic configuration diagram of a conventional HMD.

[Explanation of symbols]

1 video signal 2 control circuit 3 light sources 4 Collimating optical system 5 Scanning optical system 6 Collimating lens 7 M lens array 8 aerial image panel 9 Eyepiece optical system 9a Prism refracting surface 9b Plane (total reflection surface) 9c Free curved surface reflective surface 10 Observer 11 light beams 11a light beam R 11b light beam G 11c light beam B 31 micro plane mirror 32 torsion bar x 33 torsion bar y 51 image points 71 Scanning optical system 71a Horizontal scanning system 71b Vertical scanning system 72 Light source 81 color composition system 101 Eyepiece optical system 102 Distance changing device 111 Illumination optical system 112 LCD panel 113 diffuser 114 Eyepiece optical system 115 Observer 121 light source 122 Collimating lens 123 Scanning optical system 124 Intermediate image plane 125 eyepiece optical system 126 Observer

Claims (6)

[Claims] 1. An image observation apparatus for observing a two-dimensional image as an aerial image through an eyepiece optical system, a light source for emitting a light beam, and a condensing optical system for condensing the emitted light beam. A scanning optical system for scanning the condensed light beam, a lens array for condensing the scanned light beam to form an image of a light source, and the scanned light beam for each of the lens arrays. An eyepiece optical system for observing, as an aerial image, a two-dimensional image formed by sequentially forming an image near a focal point of a lens, a scanning image observation apparatus. 2. The scanning image observation apparatus according to claim 1, wherein the scanning optical system is composed of at least one vibrating mirror having two orthogonal rotation axes. 3. The scanning optical system is a minute plane mirror in which a horizontal scanning system for forming a two-dimensional image is resonantly driven,
2. The scanning image observation apparatus according to claim 1, wherein the vertical scanning system is composed of a galvano mirror. 4. The scanning optical system is arranged in the vicinity of the focal point of the condensing optical system, and has a collimating lens between the scanning optical system and the lens array. Scanning image observation device. 5. The scanning image observation according to claim 1, further comprising a modulation unit that expresses a gradation of a two-dimensional image by modulating the intensity of the light source in accordance with a video signal. apparatus. 6. A distance changing device for changing the size of a two-dimensional image formed by changing the distance between the scanning optical system and the lens array. Scanning image observation device.