Near-to-eye display device

A near-to-eye display device includes a display image source (01) which includes an electronic display and is used for generating image light; an collimating device (02) which includes a microlens array including refraction microlens units having approximately the same focal length, wherein a distance between the collimating device (02) and the display image source (01) is approximately the focal length of the refraction microlens units, the collimating device (02) is used for collimating the image light emitted by the display image source (01); and a light control assembly (03) which includes light refraction microprism units having a one-to-one correspondence to the refraction microlens units each of which has a planar surface, the light control assembly is used for controlling a propagation direction of the image light. The refraction microlens units and the light refraction microprism units are arranged with a filling coefficient as close to 1 as possible.

BACKGROUND OF THE PRESENT INVENTION

Field of Invention

The present invention relates to an optical display device used in computer equipment, and more particularly to an imaging system for a near-to-eye display device.

Description of Related Arts

In recent years, head-mounted computer equipment has developed rapidly. VR (virtual reality), AR (augmented reality) and MR (mixed reality) devices emerge in endlessly. However, the optical structure of most existing VR display devices restricts the further reduction of their volume.

This situation limits the development and popularity of VR display devices.

Therefore, a lightweight, inexpensive, simple manufacturing process and large field of view optical device is needed.

SUMMARY OF THE PRESENT INVENTION

An object of the present invention is to provide an optical device which is able to resolve the above problem. Through an optical device which includes a collimating device and a light control assembly both of which have a specific structure, the VR equipment is reduced in volume and low in cost, and is easy to popularize.

Accordingly, a near-to-eye display device comprises a display image source, a collimating device and a light control assembly.

Preferably, the display image source is an OLED (organic light-emitting diode) display, an LCD (liquid crystal display) or a micro-LED display.

Preferably, when refraction microlens units of the collimating device are dynamic lenses or microlenses with electronically controlled focal length, the near-to-eye display device is able to better adapt to diopter of an observer's eyeball.

Preferably, the refraction microlens units of the collimating device are able to be instead with diffraction microlens units for collimating.

Preferably, the refraction microlens units of the collimating device have a one-to-one correspondence with pixel units of the display image source.

Preferably, the refraction microlens units of the collimating device and light refraction microprism units of the light control assembly need to be arranged with a filling coefficient as close to 1 as possible; the refraction microlens units of the collimating device have a one-to-one correspondence with the light refraction microprism units of the light control assembly; and a shape of vertical projections of the light refraction microprism units of the light control assembly on the display image source is approximately the same as that of the refraction microlens units of the collimating device on the display image source.

Preferably, a deflection angle, of the light refraction microprism units of the light control assembly to the image light which is perpendicular to a plane where the display image source is provided after being collimated by the collimating device, should increases with an increase of a distance between the light refraction microprism units and an optical axis of the light control assembly.

Preferably, under a premise of satisfying the above conditions, an arrangement of two adjacent light refraction microprism units of the light control assembly should satisfy a condition that virtual images formed by the image light outputted by the two adjacent light refraction microprism units of the light control assembly do not overlap when an observer observes.

Preferably, both the collimating device and the light control assembly are made of plastic or glass materials.

It should be understood that the foregoing general description and the subsequent detailed description are illustrative and explanatory, and are not a limitation on the protection scope of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The purposes and functions of the present invention and the methods for achieving these purposes and functions will be clarified by reference to exemplary embodiments. However, the present invention is not limited to the demonstrative embodiments disclosed below and may be realized in various forms. The essence of the specification is merely to assist those skilled in the art to comprehensively understand the specific details of the present invention.

In the conventional virtual reality display device, if the microlens array shown inFIG.1is used as the collimating lens of the image light, the virtual images formed by the image light of two adjacent refraction microlens units will inevitably overlap or mix colors, which makes it impossible for observers to observe clear virtual images.

FIG.2is a structural schematic diagram of a near-to-eye display device, in which a collimating device02is located between a display image source01and a light control assembly03, and a distance between the collimating device02and the display image source01is approximately a focal length of refraction microlens units of the collimating device02. Moreover, an optical axis of the display image source01is coincident with an optical axis of the collimating device02and an optical axis of the light control assembly03. A shape of vertical projections of light refraction microprism units of the light control assembly03on the display image source01is approximately the same as that of the refraction microlens units of the collimating device02on the display image source01.

And pixel units of the display image source01have a one-to-one correspondence with the refraction microlens units of the collimating device02and the light refraction microprism units of the light control assembly03. At the same time, the refraction microlens units of the collimating device02and the light refraction microprism units of the light control assembly03need to be arranged with a filling coefficient as close to 1 as possible.

In practical applications, due to different eye diopters of different observers, the distance between the collimating device02and the display image source01is able to be dynamically adjusted, or the focal length of the collimating device02is able to be dynamically adjusted by using a liquid crystal panel capable of realizing the function of the collimating device02.

It should be understood that the manner of one-to-one correspondence between the pixel units of the display image source01and the refraction microlens units of the collimating device02is not a necessary condition for practical applications. For example, when a static segment LCD (liquid crystal display) is used as the display image source, the static segment LCD itself does not involve the pixel concept in the general sense, so it is impossible to meet the above one-to-one corresponding condition. However, at this time, focuses of the refraction microlens units of the collimating device02on the static segment LCD are still able to be regarded as the pixel units of the display image source01.

Also, when the present invention is applied to a light field display, the collimating device02corresponds to a pixel of the display image source no longer, but a pixel island including multiple pixels.

For the aforementioned embodiment, the microlens units of the collimating device02are not only refraction microlens units inFIG.2, but diffraction microlens units with the same collimating function inFIG.3.

The collimating device02and the light control assembly03are able to be made of plastic or glass materials

FIG.4is another structural schematic diagram of the near-to-eye display device, which shows another arrangement of the light control assembly03, and at this time, the light refraction microprism units of the light control assembly02also have the function of adjusting the deflection angle of the image light.

FIGS.5and6show two situations when the light refraction microprism units of the light control assembly03have a non-planar surface. The function of this non-planar surface is to correct the aberration of the virtual image formed by the aforementioned image light, so that the observer is able to see a more accurate virtual image.

Two adjacent light refraction microprism units of the light control assembly03are capable of deflecting the image light from the display image source01that is collimated by the refraction microlens units of the collimating device02. In addition, the deflection angle of the aforementioned image light increases with the increase of the distance between the light refraction microprism units and the optical axis of the light control assembly03. Take two light refraction microprism units of the light control assembly03inFIG.7as an example, an angle between a working surface of one light refraction microprism unit which is away from the optical axis of the light control assembly03and a plane where the light control assembly03is located should be greater than an angle between a working surface of another light refraction microprism unit which is near the optical axis of the light control assembly03and the plane where the light control assembly03is located, that is, α>β is satisfied.

At the same time, the deflection angle of the light refraction microprism units of the light control assembly03to the aforementioned image light needs to satisfy a condition that the virtual images formed by the image light outputted by the two adjacent light refraction microprism units of the light control assembly03do not overlap when the observer observes.

Under the existing technical conditions, the collimating device02and the light control assembly03are able to be made of plastic or glass materials.

FIG.8shows the arrangement requirement that the light refraction microprism units of the aforementioned the light control assembly03, in which the light control assembly03has a planar surface in a stereoscopic manner, that is, γ>δ.

In order to facilitate understanding of the specific intent of the present invention,FIG.9is a stereoscopic diagram which shows that 9×9 light refraction microprism units of the light control assembly03each of which has a planar surface are arranged in a square manner, in which an optical axis of one of the 9×9 light refraction microprism units which is located at a middle of the 9×9 light refraction microprism units is an optical axis of the light control assembly03.

Referring toFIGS.10and11, the refraction microlens units of the collimating device02and the corresponding light refraction microprism units of the light control assembly03are able to be arranged in a square or regular hexagon manner in practical applications, that is, it is necessary to obtain a filling coefficient as close to 1 as possible to improve the utilization efficiency of image light. Obviously, in practical applications, the rectangular arrangement and the equilateral triangle arrangement are also feasible.

Referring toFIG.12, the optical axis of the light control assembly03is consistent with the optical axis of the observer's eyeball, and simultaneously it is necessary to ensure that the light refraction microprism units of the light control assembly03still have a one-to-one correspondence with the refraction microlens units of the collimating device02. Therefore, under the above conditions, a quantity of the light refraction microprism units of the light control assembly03should be greater than a quantity of the refraction microlens units of the collimating device02, and a dynamic adjustment amplitude of the light control assembly03should be minimized by a size of the light refraction microprism units of the light control assembly03, so that at this time, the deflection angle of the emitted image light is dynamically adjusted by the light refraction microprism units of the light control assembly03.

Referring toFIG.13, the light refraction microprism units of the light control assembly03are embodied as liquid crystal devices, so that at this time, without moving the light control assembly03, the deflection angle of the emitted image light is dynamically adjusted by the light refraction microprism units of the light control assembly03.

Referring toFIG.14, in order to simplify the components, the refraction microlens units of the collimating device02are attached to a surface of the light refraction microprism units of the light control assembly03respectively. It should be noted that, in practice, the focal length of the refraction microlens units of the collimating device02may be less than a thickness of a substrate, so for high-resolution applications, a surface of the substrate with the collimating device02and the light control assembly03after processing should face away from the observer's eyeball, so as to ensure that the distance between the collimating device02and the display image source01is approximately the focal length of the refraction microlens units of the collimating device02. And for some application scenarios with low resolution, especially when the focal length of the refraction microlens units of the collimating device02is greater than the thickness of the substrate, the surface of the substrate with the collimating device02and the light control assembly03faces away from the display image source01according to the actual situation.

FIG.15shows the combination of the near-to-eye display device provided by the present invention with an optical waveguide device. The image light outputted by the display image source01, after being collimated by the collimating device02and being adjusted in the deflection angle by the light refraction microprism units of the light control assembly03, falls into an optical waveguide substrate, and then is emitted by the optical waveguide substrate, and finally enters the human eye. This application method combines the volume advantage of the near-to-eye display device provided by the present invention with the light and thin advantage of the optical waveguide substrate, so as to realize the design of lighter AR (augmented reality) glasses.

It should be understood that the aforementioned optical waveguide device is only an illustrative example, and the present invention is also applicable to other existing optical waveguide devices.