KR100304621B1 - Image illumination device for head mounted display - Google Patents

Abstract

PURPOSE: An image illumination device for head mounted display is provided to form compactly a head mounted display by changing a structure and an optical alignment of an optical unit. CONSTITUTION: A light source(30) is used for generating and irradiating light. A polarizer(43) is used for transmitting a part of the light radiated from the light source(30). A polarization beam splitter(45) is arranged on a light path in order to change a polarizing direction of incident ray by transmitting or reflecting the incident ray according to polarization components. A spherical reflective mirror(49) is used for reflecting the incident ray from the polarizer and the polarization beam splitter(45). A 1/4 wavelength plate(47) is arranged on the light path between the polarization beam splitter(45) and the spherical reflective mirror(49) in order to change a polarizing direction of the incident ray. A reflective display device(50) for generating an image from the incident ray and reflecting the incident ray.

Description

Display lighting device for head mounting

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image lighting apparatus for a head mounted display, and more particularly, to a head mounted display image illuminated having a structure in which the head mounted display can be compacted and a uniform image can be obtained by changing the configuration and optical arrangement of the optical unit. Relates to a device.

In general, a head mounted display (hereinafter referred to as an HMD) generates an image using a display element such as a liquid crystal display (LCD), and uses the mirror to generate a large screen. This is a device that enlarges the image and uses it while it is attached to the head during viewing.

1 is a schematic diagram showing an optical arrangement of a conventional HMD. As shown, the conventional HMD includes a backlight light source 11, image generating means 15 for selectively transmitting the light irradiated from the backlight light source 11 to generate an image, a spherical reflector 19, The light transmitted through the image generating means 15 is reflected toward the spherical reflector 19, and the light reflected by the spherical reflector 19 includes a half mirror 17 for transmitting the light toward the viewer's eyes.

The HMD configured as described above is enclosed and installed in the housing 20 of the structure to be mounted on the head, and the light reflected from the spherical reflector 19 and transmitted through the half mirror 17 passes through the window 22. Head into the eye 24.

The backlight light source 11 is composed of a lamp 12 which is a light emitting body such as a fluorescent lamp, and a mirror 13 installed on one surface of the lamp 12 so that light irradiated from the lamp 12 travels in one direction. The image generating means 15 is composed of pixels of a two-dimensional array structure, and is a transmissive liquid crystal display device 16 driven independently for each pixel unit, and a pair of polarizers installed before and after the liquid crystal display device 16. It consists of (17a) (17b). The conventional HMD configured as described above has a pair of optical systems having the configuration as shown in FIG. 1 to be used for the left eye and the right eye, respectively.

As described above, only a transmissive liquid crystal display device can be used as the image generating means, and the optical path cannot be miniaturized because the optical path between the spherical reflector and the light source must be secured.

In addition, since the light irradiated from the light source and incident on the image generating means is not included, there is a fear that an uneven image is formed on the spherical reflector.

Accordingly, an object of the present invention is to provide an HMD image lighting apparatus having a structure that can provide a uniform image by irradiating uniform light to the image generating means.

1 is a schematic diagram showing an optical arrangement of a conventional HMD.

Figure 2 is a schematic diagram showing the optical arrangement of the HMD image lighting apparatus according to an embodiment of the present invention.

Figure 3 is a view showing the optical arrangement of the focusing lens, polarizing beam splitter and spherical reflector constituting the HMD image lighting apparatus according to an embodiment of the present invention.

4 is a schematic view showing an optical arrangement of the HMD image lighting apparatus according to another embodiment of the present invention.

FIG. 5 is a schematic perspective view showing an embodiment of a scrambler employed in the HMD image lighting apparatus shown in FIG. 4. FIG.

FIG. 6 is a schematic perspective view showing another embodiment of a scrambler employed in the HMD image lighting apparatus shown in FIG. 4. FIG.

<Explanation of symbols for main parts of the drawings>

30.Light source 41.Focus lens

43 Polarizer 45 Polarizing Beam Splitter

47 ... 1/4 wavelength plate 49 ... Spherical reflector

50 ... reflective display element 60 ... scrambler

61 ... Glass Road 63 ... Body

65 ... Reflective

In order to achieve the above object, the HMD image lighting apparatus according to the present invention,

A light source for generating and irradiating light; A polarizer which transmits light of one polarization component and blocks light of another polarization component among the light incident from the light source; A polarizing beam splitter disposed obliquely on the optical path and transmitting / reflecting the incident light according to the polarization component to change its path; A spherical reflector arranged to reflect light incident from the light source and incident through the polarizer and the polarizing beam splitter; A quarter wave plate disposed on an optical path between the polarizing beam splitter and the spherical reflecting mirror to change a polarization direction of incident light; And a reflective display device that reflects from the spherical reflector and generates and reflects an image from the light incident through the quarter wave plate and the polarizing beam splitter. The image passing through the splitter is characterized in that the image is formed in the magnification optical system of the HMD.

Hereinafter, an HMD image lighting apparatus according to exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a schematic view showing an optical arrangement of the HMD image lighting apparatus according to an embodiment of the present invention.

As shown, the HMD image lighting apparatus according to an embodiment of the present invention is a light source 30, a polarizer 43 for transmitting light of one polarization component of the light incident from the light source 30, and incident light The optical path between the polarizing beam splitter 45, the spherical reflector 49, and the polarizing beam splitter 45 and the spherical reflecting mirror 49 to selectively transmit / reflect It is configured to include a quarter wave plate 47 and a reflective display element 50, which is disposed on and changes the polarization direction of incident light. Therefore, the image reflected by the reflective display device 50 and passing through the polarization beam splitter 45 is incident to the magnification optical system of the HMD and is a point where an image (image) is formed when viewed through the left and right eyes of the user. Conclude where it is perceived.

The light source 30 emits three colors of red (R), blue (B), and green (G) to be suitable for implementing white light or color images. For this purpose, the light source 30 is preferably a chip type light emitting diode (LED). Since this chip type light emitting diode itself is widely known, its detailed description is omitted.

In addition, the light source 30 may be composed of a lamp (not shown) made of xenon and halogen, and a reflector (not shown) covering a part surface of the lamp to emit light emitted from the lamp in one direction.

The polarizer 43 is disposed on an optical path between the light source 30 and the polarization beam splitter 45. The polarizer 43 transmits light of one polarization component among the light incident from the light source 30. Light is blocked to direct the light of the linearly polarized light component toward the polarization beam splitter 45.

The polarizing beam splitter 45 is disposed obliquely on an optical path between the light source 30, the spherical reflector 49, and the reflective display device 50, and selectively transmits or reflects incident light according to the polarization component, and then proceeds. Convert the path.

That is, light of one linearly polarized light transmitted through the polarizer 43 is reflected by the polarization beam splitter 45 and then directed to the spherical reflector 49, and reflected again by the spherical reflector 49. The light is reincident to the polarization beam splitter 45. Here, the quarter-wave plate 47 is disposed between the polarizing beam splitter 45 and the spherical reflector 49, and the linearly polarized light incident from the polarizing beam splitter 45 is circularly polarized light. In this case, the circularly polarized light incident on the spherical reflector 49 is converted into another linearly polarized light. For example, when the light reflected from the polarization beam splitter 45 and directed to the spherical reflector 49 is light of S polarization, the light is transmitted through the quarter-wave plate 47 twice to the polarization beam splitter 45. The light incident again becomes P-polarized light.

Therefore, the light re-incident to the polarization beam splitter 45 passes through the polarization beam splitter 45 and is incident on the reflective display device 50.

The spherical reflector 49 has its optical position and curvature determined to suit the focal position of the light incident on the reflective display element 50 and the size of the entire illumination optical system.

The reflective display device 50 is preferably a reflective liquid crystal display device having a two-dimensional array of pixels driven independently, for example, a ferroelectric LCD (FLCD) having excellent response speed characteristics. In addition, a deformable mirror device may be employed as the reflective display device 50.

FIG. 2 illustrates an optical arrangement in which light transmitted through the polarizer 43 and incident on the polarizing beam splitter 45 is reflected by the polarizing beam splitter 45, but this is merely illustrative. By changing the polarization characteristics of the riser or the polarization beam splitter, the light transmitted through the polarizer and transmitted through the polarization beam splitter may be used as the effective light. In this case, the optical arrangement of the spherical reflector and the reflective display element is also changed.

In addition, the HMD image lighting apparatus according to an embodiment of the present invention, so that the light between the polarizing beam splitter 45 and the spherical reflector 49 is disposed so as not to interfere with the light source 30, and A focusing lens 41 may be further provided on the optical path between the polarizers 43.

3 is a view showing an example of the optical arrangement of the focusing lens 41, the polarizing beam splitter 45 and the spherical reflector 49 constituting the HMD image lighting apparatus according to an embodiment of the present invention. An optical path from the object OBJ to the image plane IMG via the focusing lens 41, the polarizing beam splitter 45, and the spherical reflector 49 and the optical data of the focusing lens 41 and the spherical reflector 49. Is shown in Table 1.

Bending Radius [mm] Thickness or thickness [mm] Refractive index Dispersion OBJ ∞ 3.4000 STOP ∞ 4.0000 1.620408 60.3438 S2 -8.5000 6.0000 S3 ∞ -14.0000 S4 27.000 22.0000 IMG ∞ 0.0000

Here, the OBJ corresponds to the emission surface of the light source 30 or the emission surface of the scrambler (60 of FIG. 4) of another embodiment described later. The focusing lens 41 is a flat convex lens, and its incident surface corresponds to the STOP. S3 shows the polarization beam splitter 45, and is arranged to be inclined at 45 degrees with respect to the optical path of the incident light. The spherical reflector 49 focuses incident light with a curvature of 27.000 mm so as to be formed on the upper surface IMG.

4 is a schematic view showing an optical arrangement of an HMD image lighting apparatus according to another embodiment of the present invention.

As shown, the light source 30, the scrambler 60, the focusing lens 41, the polarizer 43, the polarizing beam splitter 45, the spherical reflector 49, the quarter wave plate 47, It is configured to include a reflective display device (50). Here, the same reference numerals as those in FIG. 2 denote the same members having the same or similar functions, and thus detailed description thereof will be omitted.

In the present embodiment, the scrambler that diffuses the light incident from the light source 30 side to uniform light incident on the reflective display device 50, and also reduces the loss of light emitted from the light source 30. 60 is provided on the optical path between the light source 30 and the focusing lens 41.

As shown in FIG. 5, the scrambler is preferably a hollow glass rod 61. The glass rod 61 has its exit surface 61b with the light incident on the incident surface 61a being diffusely reflected inside the glass rod 61 due to the difference in refractive index between the glass rod 61 and the surrounding air. By directing to the light, incident light is mixed at different positions and at different angles of the incident surface 61a to be uniform light.

The glass rod 61 may reduce the loss of light by changing the shape so that the light directed to the reflective display device 50 is proportional to the shape of the reflective display device 50. To this end, the height and width of the cross section of the glass rod 61 are proportional to the size of the reflective display device 50.

Another embodiment of the scrambler is a hollow rectangular columnar body 63 having open sides on both sides facing the light source 30 and the polarizing beam splitter 45, as shown in FIG. It may be configured to include a reflector 65 formed by coating and / or attachment to. In this case, the light incident inside the reflector 65 is reflected by the reflector 65 and is mixed toward each other toward the polarization beam splitter 45.

4, the operation of the HMD image lighting apparatus according to another embodiment of the present invention will be described.

The light generated and irradiated by the light source 30 becomes uniform light having a shape proportional to the shape of the reflective display device 50 while passing through the scrambler 60. The uniform light is incident on the polarizer 43 while focused while passing through the focusing lens 41. The polarizer 43 transmits light of one linearly polarized component of the incident light and blocks light of the other linearly polarized component. Light of one linearly polarized light component transmitted through the polarizer 43 is reflected by the polarization beam splitter 45, and is delayed by 90 ° while being transmitted through the quarter-wave plate 47 to become circularly polarized light. Is incident on the spherical reflector 49. The focused light reflected by the spherical reflector 49 passes through the quarter-wave plate 47 again and is phase-delayed by 90 ° to become light of another linearly polarized light component. This light passes through the polarization beam splitter 45 and is incident on the reflective display device 50. The reflective display device 50 is selectively driven for each pixel to selectively change the polarization component of incident light in each pixel unit. Here, the light whose polarization component is changed is reflected by the polarization beam splitter 45 and is incident to the magnification optical system (not shown) of the HMD.

As described above, the HMD image lighting apparatus according to the present invention is compacted by changing the configuration and optical arrangement of the optical unit, and has the advantage that a uniform image can be obtained by employing a scrambler.

Claims (5)

A light source for generating and irradiating light; A polarizer which transmits light of one polarization component and blocks light of another polarization component among the light incident from the light source; A polarizing beam splitter disposed obliquely on the optical path and transmitting / reflecting the incident light according to the polarization component to change its path; A spherical reflector arranged to reflect light incident from the light source and incident through the polarizer and the polarizing beam splitter; A quarter wave plate disposed on an optical path between the polarizing beam splitter and the spherical reflecting mirror to change a polarization direction of incident light; And a reflection type display element which is reflected from the spherical reflector and generates an image from the light incident through the quarter wave plate and the polarizing beam splitter and reflects the same. And an image reflected by the reflective display element and passed through the polarizing beam splitter is formed in the magnification optical system of the HMD. The HMD image lighting apparatus according to claim 1, further comprising a scrambler disposed on an optical path between the light source and the polarizing beam splitter to diffusely reflect the light emitted from the light source so as to be uniform light. The scrambler of claim 2, wherein And a rectangular columnar glass rod that changes its shape so that light directed toward the reflective display element is proportional to the shape of the reflective display element. The scrambler of claim 2, wherein A hollow rectangular pillar-shaped body having openings on both sides facing the light source and the polarizing beam splitter; And a reflector formed by coating and / or attachment inside the body. The HMD image illumination apparatus according to any one of claims 1 to 4, further comprising a focusing lens disposed on an optical path between the light source and the polarizing beam splitter so as to focus incident light. .