JP3935158B2 - Display device - Google Patents

Description

  The present invention relates to a display device, and more particularly, to a display device capable of expressing an optical stimulus corresponding to a visual blur causing a natural depth to be felt.

  Attempts have been made to give a high sense of realism to human visual functions by various methods. Various functions have been raised for human vision, but attention has been paid to functions such as a wide field of view and stereoscopic vision as visual functions required for creating a highly realistic display.

  In order to stimulate a wide viewing angle of a human, such as a wide viewing angle display, there is naturally a method of giving image information in an area comparable to the visual field.

  As a technique for stimulating the sense of depth of human vision, called stereoscopic viewing, there is a technique of independently inputting images with parallax between the left and right eyes. Specifically, as a stereoscopic viewing method that is widely used at present, a high-definition method that changes image information that passes through the filter by placing color filters such as red or blue in front of the left and right eyes, respectively. A method of providing lenticular lenses on the display and giving different image information to both eyes, and a liquid crystal shutter that shutters in time division in front of the eyes, changing the image information to be given to both eyes in a time division manner, etc. There is a technique.

  By the way, in the world observed by humans, it is well known that the observation with the two eyes is performed most precisely in a state where the convergence function is used, and the region where the hand can be reached from the front. In the far region, the effect of congestion cannot be expected. In other words, a short-distance area that a human is trying to gaze at can effectively use functions such as convergence by binocular vision. The function is not usefully utilized. On the other hand, forcing the binocular vision when taking a “viewing” action is not only unnecessary in view of the brain processing, but also causes unnecessary fatigue. That is, it is meaningful that a binocular vision function that is useless to use a visual function for “viewing” is not stimulated, and that a wide viewing angle display is given a characteristic that is more friendly to human visual functions.

  In general, an image that is not perceived by human beings is expressed in a state expressed as “blur”. Bokeh is a state in which the focal position of the imaging optical system is reproduced on the film surface in a photographic image or the like, and optically aberrations in the depth of focus direction remain on the imaging surface. Points to the state.

  Even in the human eyeball optical system, the refractive power of the lens in the eyeball is equivalent to the 17 mm lens in a 35 mm film camera and is considered to have a considerable depth of focus. It is thought that the image is blurred on the retina surface.

  The blurring of the image on the image plane (retinal plane) has a great influence on human vision, and is considered to include a state of gazing and a state of not gazing, and distance information.

  This method of reproducing the blurred state of the image is not only superior in high-realistic display, but also reduces the amount of information corresponding to the image of the part not being watched. It is thought that it has a great influence on the fatigue reduction of the system and the cranial nervous system that performs visual processing.

  However, existing display devices and display methods have a structure that is impossible to express such visual blur. For example, in various flat panel displays (FPDs) that are being replaced by CRTs in recent years, the blur expression on the panel surface as shown in FIG. 1A is merely a pseudo expression as shown in FIG. 1B. This is the diffusion of the contoured portion, which is an expression close to a random array of dots. In this representation, when the pixels are enlarged, as shown in FIGS. 1B and 1C, the luminance of the pixels of each RGB color is merely non-uniform, which represents true optical blur. Do not mean.

  This blur will be described below from the viewpoint of the optical system.

  When a light beam from the point light source is incident on the lens system, the light beam is condensed on the point on the image plane of the lens system, and a point image is reproduced. On the surface deviated from the image formation surface, the image is not formed as a point but is formed in a disordered state. When there is no aberration in the incident light beam, it is projected on the image plane as a circle larger than the point. If there is an aberration, it is projected in a form that follows the aberration.

  In this example, it is expressed as a point light source, but it can be considered that an actual visual field forms an image according to this. However, as described above, an image of a panel display basically has only a pixel structure, and such natural blur cannot be expressed.

  As described above, current display devices are structurally impossible to express visual blur and have a problem that natural blur cannot be displayed.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a display device capable of displaying natural blur by blurring the image on the retinal surface.

According to this invention,
A light projection plane has a second focal point should be determined at the first focal point and the observer on the eye, have a second direction perpendicular to the first direction and the first direction and projects a display image,
A light source unit that generates light rays;
A waveguide structure for guiding a light beam from the light source unit, which has flexibility and has a movable waveguide that is vibrated in the first direction. A waveguide structure from which rays deflected in one direction are emitted;
A condenser lens system for condensing the emitted light beam toward the first focus ;
Wherein arranged at the focal point of the light beam that matches the first focal point, and a deflection unit for deflecting the light beam along the second direction to form the display image on the light projection surface, and said condensing disposed between the point and the light projection plane, an electro-optical element that causes an optical blur refractive index in accordance with the blurring of the display image is changed,
A light emission control circuit for driving the light source unit according to an image signal and generating a modulated light beam from the light source unit;
A display device is provided.

Moreover, according to this invention,
In a method of displaying an image on a light projection surface having a first focus and a second focus to be defined on the observer's eyeball, the first direction and a second direction perpendicular to the first direction.
Drive the light source unit according to the image signal to be displayed to generate a modulated light beam from the light source unit,
One end of the movable waveguide having flexibility leads to light from the light source unit, the movable waveguide is vibrated to emit a light beam deflected in the first direction from the free end of its other end,
In a state where the emitted light beam is condensed toward the condensing point coincident with the first focal point, the light beam at the condensing point is deflected along the second direction,
An optical blur is provided by changing an optical path length with respect to a light beam for displaying a blur region included in the display image between the light projection surface and the condensing point ,
There is provided a display method characterized in that the image is displayed on the light projection surface by the light beams deflected in the first and second directions, and the image is projected onto the eyeball of the observer .

    According to the present invention, it is possible to provide a display device capable of displaying a natural depth feeling and displaying an image corresponding to a visually blurred image.

  Prior to the description of the embodiments of the present invention, first, the inventors will focus on the focus of the present invention.

  The inventor has proposed in Japanese Patent Application No. 2003-193907, which has already been filed, a display device capable of wide-field observation while being small in size. This display device realizes wide-field display with a small device by forming an optical scanning image on the retina surface as described below as an embodiment. In such a display device, when the light beam emitted from the light source unit is projected while collecting the focal point of the two-dimensional image on the pupil of the observer while maintaining the condensed state, Since the image formation on the retinal surface has a long depth of focus, it is possible to maintain the image formation state on the retinal surface regardless of the adjustment state of the eyeball. Such a state is known as Maxwell's view, but the necessary elements here need to maintain a condensing state sufficient to handle all the light beams constituting the two-dimensional image as parallel light beams.

  Even if such a condensing state cannot be obtained, if an image of the emission source that gives the primary light scanning of the light beam is formed on the retinal surface together with the adjustment of the eyeball, the light source of the emission source It is possible to form an image as a collection of minute light spots that maintain the shape of In other words, when the display device system according to the present invention is used, image display can be considered as a collection of point light sources, and natural blurring is expressed by changing the imaging state of the point light sources. It is possible.

  A display device according to an embodiment of the present invention based on such a viewpoint will be described below with reference to the drawings.

  FIG. 2 is a plan view schematically showing a planar arrangement relationship in the display device according to the embodiment of the present invention. The display device shown in FIG. 2 includes a two-dimensional light scanning device 10, which includes a primary light scanning unit 11, a condensing lens system 12, a secondary light scanning unit 13, and secondary light. The motor 14 for driving which operates the scanning unit 11 is comprised.

  A two-dimensional scanning light beam L is emitted from the two-dimensional optical scanning device 10 toward the projection surface 15. Accordingly, the projection surface 15 is scanned with the two-dimensional scanning light beam L, and an optical scanning image 40 is formed on the projection surface 15 by the two-dimensional scanning light beam L from the two-dimensional optical device 10. Here, the optical scanning image 40 is, for example, about 50 degrees left and right (100 degrees in total), 35 degrees above and 50 degrees below (85 degrees in total) (guide visual field) It is formed in the range defined above the value.

  The condensing lens system 12 is composed of a first lens and a second lens, respectively. The first lens arranged on the optical scanning unit 11 side is a light emission source that can be regarded as a single light source in the primary light scanning unit 11. The first lens has a focal length at which the rear focal point is located, and the first lens converts the scanning light beam from the emission source of the optical scanning unit 11 into a parallel light beam. The parallel light beams emitted from the first lens are condensed toward the secondary light scanning unit 13 by the second lens of the condensing lens system 12 and are respectively tilted by the driving motor 14. The projection unit 15 is scanned by the scanning unit 13. That is, the secondary light scanning unit 13 deflects the light beam from the second lens of the condenser lens system 12 and scans the projection surface 15 with the deflected light beam. The secondary light scanning unit 13 includes a polygon of about 5 mm square that is operated in synchronization with the vibration period in the primary direction (horizontal direction) of the cantilever structure 31 provided in the optical scanning device 10 shown in FIG. It consists of deflection elements such as mirrors, galvanometer mirrors, and acousto-optic elements. The secondary light scanning unit 13 is actuated by a motor 14 controlled by the control unit 17 and its optical path is tilted.

  In the optical scanning device 10 shown in FIG. 2, a cantilever structure 31 to be described in detail later is vibrated, and a light beam is subjected to primary scanning (corresponding to horizontal scanning), and is synchronized with the vibration of the cantilever structure 31. The light path is incident on the secondary light scanning unit 13 that is tilted. The light beam reflected by the secondary light scanning unit 13 is subjected to secondary scanning (corresponding to vertical scanning) as the optical path is tilted. Therefore, the light beam emitted through the secondary light scanning unit 13 is converted into a light beam deflected two-dimensionally (corresponding to horizontal and vertical scanning). For example, when the secondary light scanning unit 13 is tilted at 1800 rpm by the motor 14, two-dimensional scanning at a frame rate equivalent to 60 Hz is possible.

  In use, the optical scanning device 10 shown in FIG. 2 is mounted on the side surface of the observer's head, and the reflective projection surface 15 formed on the concave reflection surface on which the projection image 40 is formed is It is arranged on the line of sight. Accordingly, the light beam L from the optical scanning device 10 is directed to the reflective projection surface 15 disposed in front of the observer's eyes, and is reflected by the reflective projection surface 15 and collected toward the eyeball 55 of the observer. . Therefore, the observer can observe the projection image 40 with the light beam incident from the reflective projection surface 15. According to the display device shown in FIG. 2, an observer can observe an image display with a wide viewing angle by the optical scanning device 10 and the reflective projection surface 15 attached to the observer.

  When the image (two-dimensional light beam) is projected onto the retina surface of the eyeball 55 as shown in FIG. 2, the reflective projection surface 15 can be realized by an optical system having a diffraction or reflection function in front of the eyes of the observer. . The projection image formed on the reflective projection surface 15 is directed toward the observer's eyeball 55, and the reflected image or diffraction image thereof is projected onto the observer's retina surface, thereby giving image information to the observer. The apparatus for realizing the reflective projection surface 15 is designed, for example, in the shape of glasses, so that the observer can hardly feel uncomfortable wearing the apparatus. The reflective projection surface 15 is formed on a three-dimensional ellipsoid having two focal points using, for example, aluminum vapor-deposited plastic, and one of the focal points coincides with a condensing point of a light beam generated in the secondary light scanning unit 13. The other focus is determined so as to be matched with the pupil opening of the eyeball 55. By setting the focal point in this way, all the two-dimensional light beams formed by the optical scanning device 10 can be imaged on the retina of the eyeball 55. In addition, when aluminum vapor deposition plastic is used, external light from the viewing direction cannot be taken in, but by using a holographic lens or the like on the reflective projection surface 15, a display device that can be seen through can be obtained.

  As shown in FIG. 2, an electro-optical element 18 is disposed in the optical path between the secondary light scanning unit 13 and the projection surface 15. The electro-optic element 18 changes its refractive index from the initial refractive index n0 to a certain refractive index nx by applying a high electric field by a drive signal from the control unit 17. When the refractive index of the electro-optical element 18 in the resting state is the initial refractive index n0, the two-dimensional image projected on the projection surface 14 via the electro-optical element 18 is transmitted by the projection surface 15. The image is formed on the retina surface of the observer's eye 55. However, in a driving state in which a voltage is applied to the electro-optical element 18, the refractive index is changed to a refractive index nx, and the light beam L emitted to the projection surface 14 via the electro-optical element 18 is incident on the retina surface. An image is not formed and a good image formation state is destroyed. Therefore, when the electro-optic element 18 is driven in synchronization with the emission of a light beam forming a two-dimensional image under the control of the control unit 17, an imaging state and a non-imaging state with respect to the projection surface 15 as a display surface. Can be variably generated. That is, when projecting an image with little blur on the projection surface, the electro-optical element 18 is maintained in a resting state, and the observer's eye 55 and the light spot of the secondary light scanning unit 13 are maintained in an imaging relationship. As a result, a clear image is incident on the retina surface of the observer's eye 55. On the other hand, when projecting an image with much blur on the projection surface, the electro-optic element 18 is switched to the driving state, the optical path length is changed, and the light spot of the observer's eyes 55 and the secondary light scanning unit 13 is changed. As a result, the blurred image is projected onto the retina surface of the observer's eye 55. The blurred image is different from the pseudo blur generated in the pixel arrangement of the display element or the like, and is blurred in the optical system that transmits the optical image. Therefore, the blurred image is perceived by the observer as a natural blur, and there is no sense of incongruity. Be recognized.

  The structure of the primary light scanning unit 11 incorporated in the light scanning device 10 shown in FIG. 2 will be described with reference to FIGS.

As shown in FIGS. 3 and 4, the primary light scanning unit 11 includes an SOI substrate structure 21 that constitutes a light source element unit. As shown in FIG. 5, in the SOI substrate structure 21, an optical element is formed on a silicon (Si) substrate 21-1 using a microfabrication technique used in a semiconductor process. That is, as shown in FIG. 5, a silicon oxide (SiO ₂ ) layer 21-2 is formed in a partial region on the silicon substrate 21-1, and a silicon active layer 21-3 is formed on the silicon oxide layer 21-2. Thus, the SOI substrate structure 21 is formed. On the silicon active layer 21-3, a light source element 36 composed of a semiconductor laser, a light emitting diode or the like is formed, and an optical waveguide structure 35 for guiding the light beam from the light source element 36, and a light beam from the light source element 36 is an optical waveguide structure. Condensing part structures 39-1 and 39-2 for condensing light 35 are formed. In the optical waveguide structure 35, an optical waveguide material is applied on the SOI substrate 21-1, and the applied optical waveguide material is exposed by a resist technique, and then is cut into an optical waveguide by RIE processing, so that the silicon oxide layer 21-2 is formed. By etching as a sacrificial layer, the movable part is formed by releasing the beam structure from the silicon substrate 21-1.

  As an example, a polymethacrylate resin is basically used as a constituent material of the optical waveguide structure 35. However, other typical optical waveguide materials include polycarbonate resins, polystyrene resins, polyolefins, and various metals. There are oxides, metal nitrides, and the like. In this example, the thickness of the optical waveguide structure 35 is about 10 μm, and the exit end of the optical waveguide has a cross-sectional shape of 10 μm square. From such a molding process, the optical waveguide structure 35 is reduced in a cone shape toward the base portion 35B of the needle-shaped waveguide portion 35A, and the needle-shaped waveguide portion 35A extends from the tip of the cone-shaped upper portion 35A. It is. Similarly, the silicon active layer 51-3 extends in a needle shape with a gap between the silicon active layer 51-3 and the silicon substrate 51-1 so as to support the needle-shaped waveguide portion 35A, and the silicon oxide layer 51 together with the needle-shaped waveguide 35A. -2 is formed in a cantilever structure 31 fixed to -2. This cantilever structure 31 is composed of a flexible needle-shaped waveguide 35A having one end fixed, its tip is defined as a free end, and its free end is defined as a light beam exit end. Yes. As an example, the cantilever beam structure 31 has a beam width of about 10 μm and a length of about 1300 μm.

  In the structure shown in FIG. 5, the light beam generated from the light source element 36 is condensed on the optical waveguide structure 35 by the condensing unit structures 39-1 and 39-2, and the condensed light beam is the optical waveguide structure. It is propagated through the inside 35, is intensively introduced into the base 35B of the needle-like portion 35A, and is ejected from the tip 35C to the outside. Therefore, the base portion 35B of the needle-shaped portion 35A of the optical waveguide structure 35 corresponds to the light spot of the light source element 36 in the display device shown in FIGS. As will be described later, the rear focal point of the lens of the condenser lens system 12 is aligned with the base portion 35B of the needle-shaped portion 35A of the optical waveguide structure 35.

  The cantilever structure 31 supporting the needle-like portion 35A for deflecting the needle-like portion 35A of the optical waveguide structure 35 is connected to a deflection mechanism 38. In other words, in the deflection mechanism 38, the cantilever beam structure 31 is connected to the bellows spring structure 34, and both ends of the bellows spring structure 34 are connected to the comb drive mechanism 32. The bellows spring structure 34 is supported by the stabilization spring structure 33, and supports the cantilever structure 31 so that it can be finely displaced in the extending direction stably. The comb-shaped drive mechanism 32 and the stabilization spring structure 33 are fixed to the frame 60 of the primary light scanning unit 11, and a voltage is applied to the comb-shaped mechanism 32 from the control unit 17 via wiring. . In the comb-shaped mechanism 32, an electrostatic driving force is generated from the capacitance generated between the comb teeth according to the applied voltage, and the bellows spring structure 34 has this electrostatic driving force generated in the comb-shaped mechanism 32. Is transmitted to the cantilever 11. Further, since the bellows spring structure 34 has a bellows structure, the small amplitude of the comb-tooth mechanism 32 is amplified, and the cantilever structure 31 is unevenly distributed in a relatively large arc shape in the horizontal direction indicated by an arrow HD in FIG. Can be converted into amplitude fluctuations. One side of the stabilizing spring structure 31 is connected to the frame 60 of the optical scanning unit 11, and the operation is stabilized so that the interdigitated comb teeth of the interdigital mechanism 32 move perpendicularly to each other. The vibration speed (scanning speed) of the cantilever structure 31 is determined by the resonance frequency depending on the physical constants of the constituent members such as the bellows spring structure 34, the stabilization spring structure 31, and the comb-shaped mechanism 32 that constitute the deflection mechanism 38. It is done.

  When the deflection mechanism 38 operates, the needle-shaped portion 35A of the optical waveguide structure 35 together with the cantilever structure 31 is oscillated in an arc shape in the horizontal direction. Light rays are deflected in the horizontal direction. Accordingly, the primary light scanning unit 11 emits a light beam that spreads in a fan-shaped manner in the horizontal direction. A color display device is realized by preparing primary light scanning units 11 and 21 having light sources that individually generate red (R), green (G), and blue (B) rays as the light source elements 36, respectively. I can do it.

  As shown in FIGS. 6A and 6B, in the one-dimensional optical scanning device 10, a correction lens 16 is provided in front of the primary optical scanning unit 11. As the needle-like portion 35A of the optical waveguide structure 35 is changed by the deflection mechanism 38, the tip 35C of the needle-like portion 35A is finely moved. In order to correct the variation of the emission point, the correction lens 16 is provided with a plano-convex lens, for example. The correction lens 16 acts as a kind of fθ lens, gives aberration according to the position of the emission point that fluctuates periodically, and the light spot does not move to the base portion 35B of the needle-like portion 35A of the optical waveguide structure 35. The light beam emitted from the emission point is corrected. By providing the correction lens 16, an immovable light spot is positioned on the base portion 35 </ b> B of the needle-like portion 35 </ b> A of the optical waveguide structure 35, and the rear focal point of the first condenser lens of the condenser lens system 12 is guided. It can be located at a stationary light spot located on the base portion 35B of the needle-like portion 35A of the waveguide structure 35.

  In the display device shown in FIG. 2, a normal video signal is input to the control unit 17 as shown in FIG. 7. In the control unit 17, a video signal is input for each frame image, the frame image is temporarily stored in the frame memory 66, and the video signal is input to the image analysis unit 60 to analyze the image.

  In the image analysis unit 60, the luminance distribution of the input frame image is analyzed, and it is determined whether the frame image is a blurred image or a sharp frame image with a clear outline. That is, whether the image signal for each horizontal scanning line constituting the frame image is differentiated and whether the differential value in the differentiated signal exceeds a predetermined threshold Th1, Th2 or not is a sharp area in each line. Alternatively, it is determined whether the area is blurred.

  The blurred region of the image in one frame is displayed with the luminance diffused, and the luminance is gradually changed when attention is paid to each line in the one frame. On the other hand, the sharp region of the image in one frame corresponds to a region where the brightness of the image is remarkably changed because the outline of the image is clear and the brightness is clear. When attention is paid to each line in one frame, an area between pixels in which the luminance corresponding to the contour of the image changes remarkably corresponds to a sharp area. Therefore, it is possible to extract a blurred area and a sharp area from each frame image by differentiating the luminance signal (which is also a modulation signal).

  Specifically, a luminance signal (also a modulation signal) for each horizontal line is differentiated to obtain a differential signal for each line as shown in FIG. This differential signal is fluctuated with a change in luminance, but in a region where blur occurs, the fluctuation level of the differential signal is relatively small as shown at time points t0 to t1, and when reaching a sharp region, As shown at time t1, the differential signal greatly exceeds the threshold value Th2, which is greatly fluctuated. Further, when the region from the sharp region to the blurred region is reached, the differential signal is greatly fluctuated and similarly exceeds the threshold Th2 as shown at time t2. Accordingly, the region at the time point t1 to t2 that exceeds a certain threshold Th2 is determined as a sharp image region. Similarly, in the graph of FIG. 8, since the differential signal fluctuates beyond a certain threshold Th1 from time t3, it is determined that a sharp image area has occurred from time t3.

  In the image analysis unit 60, a map of a sharp region and a blurred region in one frame is stored in the memory unit 62 in accordance with the variation of the differential signal. In this map, a sharp area and a blurred area are designated as a pixel address like a sharp pixel and a blurred pixel for each pixel. Preferably, the range of the sharp image area is enlarged on the map in consideration of the response of the electro-optical element 18. That is, in the example shown in FIG. 8, not only the time points t1 to t2 but also a pixel including a time point (t1-Δ) before the time point t1 when the sharp image region starts is registered in the map as a sharp image region. Is preferred.

  From the frame memory 66, the image signal for each line is supplied to the image processing unit 68, and the image processing unit 68 extracts the modulation signal and the horizontal and vertical scanning signals from the image signal. The modulation signal is supplied to the light emission control circuit 70, and a light source drive signal corresponding to the modulation signal is generated and supplied to the light source element 36 of the primary light scanning unit 11. In addition, a horizontal scanning signal and a vertical scanning signal are supplied to the drive signal generating unit 72, and a driving signal for operating the comb-shaped mechanism 32 is generated from the driving signal generating unit 72 according to the horizontal scanning signal, and according to the vertical scanning signal. Similarly, a drive signal for operating the motor 14 is generated from the drive signal generator 72. Therefore, a light beam modulated from the light source element 36 is generated according to the modulation signal, and the primary light scanning unit 11 and the secondary light scanning unit 13 are connected to the units 11 and 13 according to the horizontal and vertical scanning motion signals. The light beam incident on the beam will be deflected. In the operation of the primary light scanning unit 11, the comb-shaped mechanism 32 is operated by a drive signal corresponding to the horizontal scanning signal, the cantilever structure 31 is resonantly oscillated, and the light beam is deflected in the horizontal direction. In the operation of the secondary light scanning unit 13, the driving motor 14 operates according to the vertical scanning motion signal, and the deflecting element of the secondary light scanning unit 13 tilts the optical path to deflect the light beam in the vertical direction. Further, a light beam deflected in the horizontal direction is emitted from the primary light scanning unit 11, and this light beam is deflected in the vertical direction by the secondary light scanning unit 13 and the light beam L is directed to the projection surface 15. Accordingly, a projection image 40 is formed on the projection surface 15 by the two-dimensional optical device 10.

  When the frame image is output from the frame memory 66 in the control unit 17 shown in FIG. 7, an on / off signal corresponding to the map is given from the memory unit 62 to the element driving unit 64 in synchronization with this output. That is, an on / off signal is output according to the corresponding pixel in accordance with the pixel signal for each line from the frame memory 66. Here, an off signal is generated for a pixel signal corresponding to a pixel in a sharp image region, and an on signal is generated for a pixel signal corresponding to a pixel in a blurred image region. Accordingly, a drive signal is given in response to the ON signal from the element driving unit 64 that drives the electro-optical element 18, and the electro-optical element 18 is driven. Further, in response to the off signal, the element driving unit 64 stops the voltage application to the electro-optical element 18 and puts the electro-optical element 18 into a resting state. Since the on / off signal is generated corresponding to the pixel, when a pixel having a continuous blur region is displayed, the refractive index of the electro-optical element 18 is increased to nx, and the optical path length of the optical system is increased. As a result, the light flux passing through the electro-optic element 18 is optically blurred. Further, when a pixel having a continuous sharp region is displayed, the refractive index of the electro-optical element 18 is maintained at n0, and the light beam passing through the electro-optical element 18 passes through the electro-optical element 18. This contributes to the rendering of the original sharp image.

  As described above, when a blurred area is included in the image to be displayed, the refractive index of the electro-optic element 18 is changed from a predetermined value when the blurred area is displayed, and optical blur is given to the light flux. If the sharp image region is included in the image to be displayed, the refractive index of the electro-optic element 18 is returned to the original value when displaying the sharp image region. A sharp image of the relationship is displayed. Therefore, an image including natural optical blur is displayed on the displayed image, and a display without a sense of incongruity is possible.

  A display device according to another embodiment of the present invention will be described with reference to FIG. Since the element shown in FIG. 9 has a structure similar to the structure shown in FIG. 5, detailed description thereof will be omitted by attaching the same reference numerals.

  In a display device according to another embodiment of the present invention, instead of arranging an electro-optical element in the optical path between the two-dimensional optical scanning device 10 and the projection surface 15 as shown in FIG. As shown, the electro-optic element 15 may be incorporated in the element portion in the one-dimensional optical scanning unit 11. That is, the electro-optical element 15 is disposed between the light source element unit 36 and the light condensing unit structure 39-1, and the light beam emitted from the light source element unit 36 is directly optically blurred according to the blur in the image. It may be given to the luminous flux.

  The electro-optic element 15 has a small change in refractive power, and therefore, as shown in FIG. 2, an element that is equal to or larger than the scanning device body is used, and the electro-optic element 15 is externally attached to the scanning device body. I prefer that. However, when a material having a large change in refractive power is obtained with material research and development in the future, and a large element configuration is not required, a small electro-optic element as shown in FIG. It may be arranged adjacent to 36. It is also noted that the structure in which the electro-optic element is incorporated in the element structure as shown in FIG. 9 can be applied even in the case where it is not necessary to give such a large optical blur. It is obvious that this electro-optical element can obtain the same effect as that obtained by the above-described configuration by being driven in synchronization with the light emission signal.

  Further, in the above embodiment, a refractor (electro-optical element) whose refractive index is electrically changed is used as an element for changing the optical path length, but instead of this refractor, a small lens structure or a prism structure is used. The optical path length may be changed mechanically by driving the lens structure or the prism structure so as to be finely displaced by MEMS. The same effects as those of the above-described embodiment can be achieved by such an optical system and fine movement mechanical device.

(A), (b) and (c) are explanatory diagrams for explaining blur in a general display device, (a) is an explanatory diagram of an image given a certain blur, (b) is FIG. 1A is an enlarged plan view, and FIG. 1C is an enlarged plan view of FIG. 1B. 1 is a plan view schematically showing a display device according to an embodiment of the present invention. It is a top view which shows roughly the structure of the optical scanning unit integrated in the optical scanning apparatus shown by FIG. It is a top view which expands and shows a part of optical scanning unit shown by FIG. It is sectional drawing which expands and shows schematically the element part shown by FIG.3 and FIG.4. (A) And (b) is the top view and side view which show schematically the specific example of the optical scanning device shown by FIG. It is a block diagram which shows the control part shown by FIG. FIG. 8 is a waveform diagram schematically showing a signal processed by the image analysis unit shown in FIG. 7. It is sectional drawing which expands and shows schematically the element part in the display apparatus which concerns on other embodiment of this invention.

Explanation of symbols

  10. . . Two-dimensional optical scanning device; 11. . . Primary light scanning unit, 12. . . 12. condenser lens system; . . Secondary light scanning unit; 14. . . Drive motor, 16. . . Correction lens, 17. . . Control unit, L. . . Two-dimensional scanning light beam, 36. . . Light source element 51. . . Substrate structure, 40. . . Optical scanning image, 31. . . Cantilever structure, 33. . . Stabilized spring structure, 34. . . Bellow spring structure, 35. . . Optical waveguide structure, 38. . . Power mechanism

Claims (6)

A light projection surface having a first focus and a second focus to be defined on the eyeball of the observer, having a first direction and a second direction orthogonal to the first direction, and projecting a display image;
A light source unit that generates light rays;
A waveguide structure for guiding a light beam from the light source unit, which has flexibility and has a movable waveguide that is vibrated in the first direction. A waveguide structure from which rays deflected in one direction are emitted;
A condenser lens system for condensing the emitted light beam toward the first focus;
A deflecting unit disposed at a condensing point of the light beam that coincides with the first focal point, and deflecting the light beam so as to follow the second direction to form the display image on the light projection surface; An electro-optic element that is disposed between a point and the light projection surface, and whose refractive index is changed according to the blur of the display image to cause optical blur,
A light emission control circuit for driving the light source unit according to an image signal and generating a modulated light beam from the light source unit;
A display device comprising:   The display device according to claim 1, further comprising: a driving mechanism configured to move the movable waveguide unit along the first direction to deflect the light beam.     The waveguide structure includes a condensing unit that condenses the light from the light source unit at a base of the movable waveguide, and the condensing lens has a rear focal point disposed at the base of the waveguide structure. The display device according to claim 1. An analysis unit that analyzes an image area corresponding to blur from the input image signal;
A drive unit that synchronizes the electro-optic element with the image signal and drives the electro-optic element according to an output signal from the analysis unit;
The display device according to claim 1, comprising:     The display device according to claim 1, wherein the electro-optic element is incorporated in the waveguide structure. In a method of displaying an image on a light projection surface having a first focus and a second focus to be defined on the observer's eyeball, the first direction and a second direction perpendicular to the first direction.
Drive the light source unit according to the image signal to be displayed to generate a modulated light beam from the light source unit,
A light beam from the light source unit is guided to one end of a flexible movable waveguide, and the movable waveguide is vibrated to emit a light beam deflected in the first direction from the free end of the other end,
In a state where the emitted light beam is condensed toward the condensing point coincident with the first focal point, the light beam at the condensing point is deflected along the second direction,
An optical blur is provided by changing an optical path length with respect to a light beam for displaying a blur region included in the display image between the light projection surface and the condensing point,
A display method, wherein the image is displayed on the light projection surface by light beams deflected in the first and second directions, and the image is projected onto the eyeball of the observer.

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