JP2013148609A - Retina projection display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a retina projection display device that supports full-color display with a simple configuration, and prevents distortion of a display image and the occurrence of color unevenness and color shift even in full-color display.SOLUTION: A retina projection display device 100 includes a laser source 1 that emits image information beams, a collimator 2 that converts the image information beams emitted from the laser source 1 into a parallel beam flux, an MEMS mirror 3 that two-dimensionally scans the image information beams of the parallel beam flux from the collimator 2, and a plate-like reflective plane-symmetric imaging element 4 to which the two-dimensionally scanned image information beams from the MEMS mirror 3 enter. Image display beams emitted from the reflective plane-symmetric imaging element 4 are focused at the center of a pupil before being projected to a retina.

Description

  The present invention relates to a retinal projection display apparatus that visually recognizes an image using Maxwell's vision, and more particularly to a retinal projection display apparatus that uses a reflective surface-symmetric image forming element that forms an image of light at a plane-symmetric position.

  2. Description of the Related Art Conventionally, a head-mounted display that projects light for visually recognizing an image on a user's retina using Maxwell's vision is known. Maxwell's vision is a method in which light corresponding to an image is once converged at the center of the pupil and then projected onto the retina. According to this method, an image can be observed without being affected by the lens's adjustment function. it can.

  For example, Patent Document 1 discloses a retinal display device using a hologram. This retinal display device performs two-dimensional scanning with image information light emitted from a laser diode, and irradiates the hologram with image information light that has been two-dimensionally scanned, so that the two-dimensional image information light diffracted by the hologram becomes the pupil of the eye It focuses on and is focused on the retina.

Japanese Patent No. 3632392

  However, when a hologram is used for a head mounted display, there is a problem that a very precise processing accuracy is required for production. In addition, when trying to support full-color display, an error of about several nanometers occurs between the hologram design wavelength and the laser wavelength for emitting image information, and the display image is distorted, or color misregistration or color unevenness occurs. There is a problem that occurs.

  The present invention has been made in view of the above circumstances, and as an example of the problem, it is possible to support full color display with a simple configuration, and even in full color display, there is no distortion of the displayed image and color unevenness and color misregistration. An object of the present invention is to provide a retinal projection display device that does not occur.

  In order to achieve the above object, an invention according to claim 1 is directed to an emission unit that emits image information light, a parallel light generation unit that uses image information light emitted from the emission unit as a parallel light beam, and the parallel light. A scanning unit that two-dimensionally scans the image information light of the parallel light flux from the generation unit; and a plate-like optical element on which the two-dimensionally scanned image information light from the scanning unit is incident, and is emitted from the optical element The image display light is converged on the center of the pupil and then projected onto the retina, whereby a retina projection display device for visually recognizing the image, wherein the optical element includes the first light reflecting surface and the first light in the plate thickness direction. A second light reflecting surface orthogonal to the one light reflecting surface, and a plurality of unit optical elements composed of the first light reflecting surface and the second light reflecting surface, and disposed on one side of the plate surface The light incident from the scanning means The image is reflected at the first light reflecting surface and the second reflecting surface in the unit optical element once each, and is imaged at the center of the pupil that is plane-symmetric with the position of the image information light incident on the scanning means. The information light is converged.

1 is a schematic configuration diagram of a retinal projection display device according to an embodiment of the present invention. It is a schematic block diagram of the laser light source used for the retinal projection display apparatus which concerns on embodiment of this invention. It is an external view of an example of a reflective surface-symmetric imaging element used in the retinal projection display device according to the embodiment of the present invention. It is an external view of the rectangular parallelepiped material which comprises the reflection type plane-symmetric image formation element shown in FIG. It is a figure which shows the combination of two mirror sheets which form the reflection type plane-symmetric image formation element shown in FIG. It is the schematic of the optical system of the spatial image display apparatus using the reflection type plane-symmetric image formation element shown in FIG. It is a schematic diagram which shows a mode that light reflects twice in the reflection type plane-symmetric image formation element shown in FIG. It is an external view of an example of the reflection type plane-symmetric image formation element used for the retinal projection display apparatus which concerns on other embodiment of this invention. It is an external view which shows the mirror surface element of the reflection type plane-symmetric image formation element shown in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of a retinal projection display apparatus 100 according to an embodiment of the present invention. The retinal projection display device 100 is a glasses-type head-mounted display (HMD), and is a device that recognizes an image by projecting image information light onto a user's retina using Maxwell's view. The retinal projection display apparatus 100 mainly includes a laser light source 1, a collimator 2, a micro electro mechanical system (MEMS) mirror 3, and a reflective plane-symmetric imaging element 4. Although FIG. 1 shows a configuration corresponding to one lens 6 of the two spectacle lenses, the same configuration is actually applied to the other lens.

  The laser light source 1 has a laser diode (LD) and emits laser light based on control of an LD driving device (not shown). The laser light source 1 corresponds to full color, and specifically, as shown in FIG. 2, a red laser output unit 11 that outputs a red (R) laser and a green laser output unit 12 that outputs a green (G) laser. And a blue laser output unit 13 that outputs a blue (B) laser, and outputs laser light of each color (each wavelength region). For example, the laser light source 1 performs intensity modulation on each color laser beam according to the image, and emits the laser beam after intensity modulation.

  In addition, the laser light source 1 includes a total reflection mirror 14 and partial transmission mirrors 15 and 16 in order to synthesize the three colors of laser beams output from the laser output units 11, 12, and 13. Specifically, the total reflection mirror 14 reflects the laser light from the red laser output unit 11, and the partial transmission mirror 15 transmits the laser light reflected by the total reflection mirror 14 and is coaxial with the transmitted light. The partially transmissive mirror 16 reflects the laser beam output from the green laser output unit 12 and transmits the laser beam from the partially transmissive mirror 15 and from the blue laser output unit 13 so as to be coaxial with the transmitted beam. The output laser beam is reflected. That is, the laser beams of the three colors output from the laser output units 11, 12, and 13 are combined on the same axis.

  The collimator 2 converts the laser light emitted from the laser light source 1 into parallel light.

  The MEMS mirror 3 is a scanning mechanism that scans laser light incident from the collimator 2 in a two-dimensional direction (up, down, left, and right shown in FIG. 1). That is, the parallel laser light becomes two-dimensional image information by scanning with the MEMS mirror 3 and enters the reflection-type plane-symmetric imaging element 4. Here, the MEMS mirror 3 is a small movable mirror. When two single-movable movable mirrors are used for two-dimensional scanning of laser light, a single movable mirror is movable in two directions. There is a case in which one laser beam is used to perform two-dimensional scanning with laser light, but any configuration may be used.

  The laser light source 1, the collimator 2 and the MEMS mirror 3 described above are disposed in the spectacle frame 7.

  The reflection-type plane-symmetric imaging element 4 is an optical element formed in a plane plate shape, and an object image that is a projection object placed on one side of the element is plane-symmetrical on the opposite side of the element. Form an image at the position. In the present embodiment, as an example, the present applicant employs an optical element disclosed in International Publication No. WO2009 / 136578 pamphlet (hereinafter referred to as Document 1).

  3 to 5 are diagrams showing the configuration of the reflective surface-symmetric imaging element 4. 3 is an external view of the reflective plane-symmetric imaging element 4, FIG. 5 is an external view of a rectangular parallelepiped material 40 constituting the reflective plane-symmetric imaging element 4, and FIG. It is an external view which shows the combination of the two mirror sheets 41 and 42. FIG.

  As shown in FIGS. 3 and 5, the reflection-type plane-symmetric imaging element 4 includes two mirror sheets 41 and 42 each formed by closely contacting a large number of rod-shaped rectangular parallelepiped materials 40 in parallel.

  As shown in FIG. 4, the rectangular parallelepiped material 40 is a long member, which is a plastic represented by transparent acrylic whose one side of a rectangular cross section in the direction perpendicular to the longitudinal direction, that is, the short direction, is around several hundred μm. It consists of a glass rod. The length varies depending on the size of the projected image, but is about several tens of millimeters. Note that three of the four surfaces extending in the longitudinal direction are surfaces used for light transmission or reflection, and thus are in a smooth state. About several hundreds of rectangular parallelepiped members 40 are used in each of the mirror sheets 41 and 42.

  As shown in FIG. 4, a light reflecting film 43 is formed on one surface of the rectangular parallelepiped material 40 extending in the longitudinal direction, thereby forming the light reflecting surface 43. The light reflecting film 43 is formed by vapor deposition or sputtering of aluminum or silver.

  For such a plurality of rectangular parallelepiped members 40, the mirror sheet 41 is brought into close contact with the opposing surface 44 opposite to the surface on which the light reflecting surface 43 of one rectangular parallelepiped member 40 is formed and the light reflecting surface 43 of another rectangular parallelepiped member 40. , 42 are formed. As shown in FIG. 5, the mirror sheets 41 and 42 are bonded together in a state in which one of the rectangular parallelepiped materials 40 is rotated by 90 degrees so that the parallel directions of the rectangular parallelepiped materials 40 intersect with each other. 4 is formed. A portion where each rectangular parallelepiped material 40 of the mirror sheet 41 and each rectangular parallelepiped material 40 of the mirror sheet 42 intersect constitutes a micro mirror unit (unit optical element), and the light reflecting surface 43 of the mirror sheet 41 of each micro mirror unit is the first. The light reflecting surface 43 of the mirror sheet 42 becomes the second light reflecting surface.

  In the spatial image display device using such a reflective plane-symmetric imaging element 4, as shown in FIG. 6, an object (display unit) 10 is disposed on one surface side of the reflective plane-symmetric imaging element 4, Light from the object 10 is incident on the reflective surface-symmetric imaging element 4 at an angle. The observer's eye E is positioned on the other surface side of the reflective surface-symmetric imaging element 4, and the real image 30, that is, the spatial image 30, is located at a spatial position that is plane-symmetric with the object 10 with respect to the reflective surface-symmetric imaging element 4. Is formed. Note that the lower end A and the upper end A ′, which are both ends of the reflective plane-symmetric imaging element 4 in FIG. 6, correspond to the opposing angles A and A ′ of the reflective plane-symmetric imaging element 4 in FIG. 3.

  In the present embodiment, when the angle α formed by the observer's line-of-sight direction and the normal direction of the plate surface of the reflective surface-symmetric imaging element 4 is 45 degrees, the reflective surface is shown so that the spatial image 30 looks brightest. The reflection type surface symmetric imaging element 4 is formed by adjusting the height D of the light reflecting surface 43 of the symmetric imaging element 4 and the interval W between the adjacent light reflecting surfaces 43. Of course, the angle α is not limited to the above-mentioned value, and is arbitrary in the range of 0 ° <α <90 °, but preferably 20 ° ≦ α ≦ 60 °.

  More specifically, as shown in FIG. 7, the light from the object 10 is reflected on the light reflecting surface 43 (second light reflecting surface) of the mirror sheet 42 in the direction of the arrow Y1, and the reflected light is reflected in the direction of the arrow Y2. Since the light is reflected on the light reflecting surface 43 (first light reflecting surface) of the mirror sheet 41 and the reflected light travels toward the observer in the direction of the arrow Y3, each light reflecting surface 43 of the reflective surface-symmetric imaging element 4 is reflected. Each of them is reflected once, that is, twice to create a mirror image.

  In the present embodiment, such a reflection-type plane-symmetric imaging element 4 is disposed in the spectacle lens 6. At this time, the reflection-type plane-symmetric imaging element 4 is disposed so as to be inclined in the line-of-sight direction in consideration of the upward writing emission angle of light in which the spatial image 30 appears bright. As a result, the laser light two-dimensionally scanned by the MEMS mirror 3 is collected in the vicinity of the center of the pupil 81 of the user's eyeball 8, which is in a plane-symmetrical position with the MEMS mirror 3, through the reflective plane-symmetric imaging element 4. Since the light is emitted and the laser light is projected onto the retina 82, the user can visually recognize the two-dimensionally scanned image information light as a two-dimensional image.

  As described above, according to the present embodiment, the reflection-type plane-symmetric imaging element 4 is used to collect the two-dimensionally scanned image information light at the center of the pupil and then form a two-dimensional image on the retina. Therefore, unlike the retinal projection display device using a hologram, precise processing accuracy is not required in its manufacture. Further, according to the present embodiment, since the reflection-type plane-symmetric imaging element 4 is used instead of the hologram, it is possible to support full-color display only by superimposing a plurality of laser beams having different wavelengths on the same axis, No graphic distortion, color shift, color unevenness, or the like occurs in the displayed full color image. As a result, it is possible to manufacture a retinal projection display device that supports full color display with a simple configuration.

  Furthermore, in the present embodiment, the retinal projection display device 10 having a see-through function can be provided by adjusting the thickness D (height of the light reflecting surface 43) of the reflective plane-symmetric imaging element 4. . That is, the user can visually recognize the image information light output as the laser light by Maxwell's view and can visually recognize the appearance of the outside world by Newton's view.

ここで、ｎは、ミラーシート４１及び４２を構成する直方体材４０（反射型面対称結像素子４）の光学屈折率、Ｄ（ｎ）は、直方体材４０の光学屈折率がｎのときのミラーシート４１及び４２のそれぞれの厚み（光反射面４３の高さ）、Ｗは、ミラーシート４１及び４２に形成された光反射面４３の間隔、αは、反射型面対称結像素子４の板面の法線に対する観察方向の角度（図６参照）、Ｘは、反射型面対称結像素子４内における光線の上記法線に対する角度である。 In the document 1, the present applicant discloses the optimum height D of the light reflecting surface 43 (the height of the light reflecting surface 43 at which the spatial image 30 looks brightest). According to Document 1,

Here, n is the optical refractive index of the rectangular parallelepiped material 40 (reflection-type plane-symmetric imaging element 4) constituting the mirror sheets 41 and 42, and D (n) is when the optical refractive index of the rectangular parallelepiped material 40 is n. The thickness of each of the mirror sheets 41 and 42 (the height of the light reflecting surface 43), W is the distance between the light reflecting surfaces 43 formed on the mirror sheets 41 and 42, and α is the reflection type plane-symmetric imaging element 4. An angle in the observation direction with respect to the normal line of the plate surface (see FIG. 6), and X is an angle with respect to the normal line of the light beam in the reflective plane-symmetric imaging element 4.

  Since the value of D (n) that satisfies the above-described equation is a value when the spatial image 30 looks brightest, that is, a value when the appearance of the outside world cannot be visually recognized, the see-through function is provided to the reflective plane-symmetric imaging element 4. In order to provide this, a value smaller than the value of D (n) may be set. Preferably, the thickness is set to about 1/5 to 4/5 times the above D (n). That is, the thickness of the reflective surface-symmetric imaging element 4 is reduced from the value when the spatial image 30 looks brightest, so that each of the light reflecting surfaces 43 of the mirror sheets 41 and 42 is reflected once, that is, twice. The light to be transmitted decreases, the brightness of the spatial image 30 becomes darker, and the light transmitted from the outside world increases, so that the see-through function is realized.

  Specifically, in the case of the present embodiment, the rectangular parallelepiped material 40 is made of a plastic or glass rod, and thus the refractive index n of the rectangular parallelepiped material 40 is about 1.5. Therefore, as an example, when α = 45 degrees, the thickness D (n = 1.5) of the reflection-type plane-symmetric imaging element 4 when the see-through function is provided is obtained from the equations (1) and (2): It is about 0.5W ≦ D (n = 1.5) ≦ 1.3W.

  As described above, in the present embodiment, the retinal projection display device 100 incorporating the reflective plane-symmetric imaging element 4 having a suitable thickness D can be created according to the purpose of use. The reflection type plane symmetric imaging element 4 may be a detachable retinal projection display device 100, and the reflection type plane symmetric imaging element 4 may be appropriately switched and incorporated in the retinal projection display device 100 according to the purpose of use. May be.

  In the present embodiment, the retinal projection display device 100 has been described as a glasses-type head-mounted display, but may be a hat-type head-mounted display (helmet-mounted display). In this case, even a person who uses glasses for correcting vision can wear the head mounted display while wearing the glasses.

  Further, the configuration of the reflection-type plane-symmetric imaging element is not limited to the configuration in which the two mirror sheets are formed by using the rectangular parallelepiped material that is the longitudinal member shown in FIGS. As long as the optical element forms an image as a real image in a plane-symmetrical position with respect to the optical element, any configuration may be used.

  For example, the configuration of a reflective surface-symmetric imaging element disclosed in Japanese Patent Application Laid-Open No. 2008-158114 may be used. FIG. 8 is an external perspective view of such a reflective surface-symmetric imaging element 5. More specifically, the reflection-type plane-symmetric imaging element 5 includes a plurality of holes 52 penetrating a predetermined base 51 in the thickness direction, and includes two mirror surface elements 54 a and 54 b orthogonal to the inner wall of each hole 52. The unit optical element 53 is formed, and when light is transmitted from one surface direction of the base 51 to the other surface direction through the hole, the light is reflected once by the two mirror surface elements 54a and 54b. You may do it. Further, as shown in FIG. 9, a large number of transparent cylindrical bodies 55 projecting in the thickness direction of a predetermined base 51 are formed on the grid, and two orthogonal wall surfaces of the inner wall surfaces of each cylindrical body 55 are formed. The reflective surface-symmetric imaging element 5A may be a mirror surface element 54a or 54b.

  Here, in the case of the retinal projection display device 200 incorporating the reflection type plane-symmetric imaging element 5 or 5A shown in FIGS. 8 and 9, since the medium through which light travels is the atmosphere, the refractive index n of the medium is about 1.0. Therefore, as an example, when α = 45 degrees, the thickness D (n = 1.0) of the reflective surface-symmetric imaging element 5 or 5A when the see-through function is provided is expressed by the equations (1) and (2). Thus, 0.3 W ≦ D (n = 1.0) ≦ 0.7 W.

  The retinal projection display devices 100 and 200 described in the above embodiments are image display devices using Maxwell's view. However, an image display device using Maxwell's view is suitable for realizing the see-through function. It is. In this case, the image projected by Maxwell's view can be visually recognized, and the outside landscape can be visually recognized by Newton's view. On the other hand, an image display device using Newton's vision is also conceivable, but in this case, since the user visually recognizes both the projected image and the outside scene using the refraction of the crystalline lens, the projected image and the outside world are viewed. You can only focus on one of the landscapes. That is, it is impossible to clearly visually recognize both the projected image and the outside landscape at the same time.

  According to the embodiment described above, the emission means (for example, the laser light source 1) that emits image information light and the parallel light generation means (for example, the image information light emitted from the emission means as a parallel light flux) A collimator 2), a scanning means (for example, a MEMS mirror 3) for two-dimensionally scanning the image information light of the parallel light flux from the parallel light generating means, and the two-dimensionally scanned image information light from the scanning means are incident. A plate-like optical element (for example, reflective plane-symmetric imaging elements 4, 5, and 5A), and the image display light emitted from the optical element is converged on the center of the pupil and then projected onto the retina. The retinal projection display apparatus (for example, the retinal projection display apparatuses 100 and 200) for visually recognizing an image, wherein the optical element has a first light reflection surface (for example, a light reflection surface 43 of the mirror sheet 41) in the thickness direction. ,mirror Element 54a) and a second light reflecting surface (eg, light reflecting surface 43 of mirror sheet 42, mirror surface element 54b) orthogonal to the first light reflecting surface, and the first light reflecting surface and the second light reflecting surface. A plurality of unit optical elements configured are provided, and light incident from the scanning unit arranged on one side of the plate surface is converted into the first light reflection surface and the second reflection surface in the predetermined unit optical element. The image information light is reflected once on the surface, and converges on the center of the pupil that is plane-symmetrical with the position of the image information light incident on the scanning means.

  According to such a configuration, a two-dimensional image is formed on the retina after condensing the two-dimensionally scanned image information light at the center of the pupil using the reflection-type plane-symmetric imaging element. As in the case of a retinal projection display device using the, a precise processing accuracy is not required in its manufacture.

  The emitting means includes a plurality of laser light emitting means (for example, a red laser output unit 11, a green laser output unit 12, and a blue laser output unit 13) for emitting laser beams having a plurality of different wavelengths, Combining means (for example, total reflection mirror 14 and partial transmission mirrors 15 and 16) for combining the respective laser lights emitted from the laser light emission means.

  In this case, full-color display can be handled only by superimposing a plurality of laser beams having different wavelengths on the same axis, and graphic distortion, color misregistration, color unevenness and the like do not occur in the displayed full-color image.

と表わされるＤ（ｎ）の値よりも小さくなるように前記第１光反射面の高さ及び前記第２光反射面の高さを設定し、シースルー機能を備えるようにしてもよい。 Further, the optical refractive index in the optical element is n, and the height of the first light reflecting surface and the height of the second light reflecting surface when the optical refractive index is n are adjacent to D (n), respectively. The interval between the first light reflecting surfaces and the interval between the adjacent second light reflecting surfaces are W, the angle of the observation direction with respect to the normal of the plate surface of the optical element is α, and the light rays in the optical element are If the angle is X with respect to the normal,

The height of the first light reflecting surface and the height of the second light reflecting surface may be set so as to be smaller than the value of D (n) expressed as follows to provide a see-through function.

  In this case, the see-through function can be realized by making the thickness of the optical element thinner than the thickness of the optical element when it looks brightest.

  The optical element may be detachable.

  In this case, for example, the reflection-type surface-symmetric imaging element having a see-through function or the reflection-type plane-symmetric imaging element having no see-through function can be replaced according to the purpose of use.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made to the embodiments of the present invention without departing from the gist of the present invention. Such modifications and changes can be made, and those accompanying such modifications and changes are also included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Laser light source 2 Collimator 3 MEMS mirror 4,5,5A Reflection type plane-symmetric image formation element 6 Lens 7 Glasses frame 10 Object (display part)
30 Real image (spatial image)
40 rectangular parallelepiped material 41, 42 mirror sheet 43 light reflecting surface (light reflecting film)
53 Unit optical element 54a, 54b Mirror surface element 100, 200 Retina projection display device

Claims (4)

Emitting means for emitting image information light;
Parallel light generating means for converting image information light emitted from the emitting means into parallel light fluxes;
Scanning means for two-dimensionally scanning image information light of a parallel light flux from the parallel light generating means;
A plate-like optical element on which two-dimensionally scanned image information light from the scanning means is incident;
With
A retinal projection display device for visually recognizing an image by causing the image display light emitted from the optical element to converge on the center of the pupil and then projecting it onto the retina.
The optical element is
A first light reflecting surface and a second light reflecting surface orthogonal to the first light reflecting surface are provided in a plate thickness direction, and a plurality of unit optical elements each including the first light reflecting surface and the second light reflecting surface are provided. The light incident from the scanning means arranged on one side of the plate surface is reflected once each on the first light reflecting surface and the second reflecting surface in the predetermined unit optical element, A retinal projection display device characterized in that image information light is converged to the center of the pupil, which is a plane symmetric with respect to the position of image information light incident on the scanning means. The emitting means includes
A plurality of laser beam emitting means for emitting laser beams having a plurality of different wavelengths;
Combining means for combining the laser beams emitted from the plurality of laser beam emitting means;
The retinal projection display apparatus according to claim 1, further comprising: The optical refractive index in the optical element is n, and the height of the first light reflecting surface and the height of the second light reflecting surface when the optical refractive index is n are D (n), respectively, The interval between the light reflecting surfaces and the interval between the adjacent second light reflecting surfaces are W, the angle of the observation direction with respect to the normal of the plate surface of the optical element is α, and the normal of the light ray in the optical element When the angle X with respect to

The height of the first light reflecting surface and the height of the second light reflecting surface are set so as to be smaller than the value of D (n) expressed as follows, and a see-through function is provided. 3. A retinal projection display device according to 1 or 2.   The retinal projection display device according to any one of claims 1 to 3, wherein the optical element is detachable.

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