CN105717643A - A reflective virtual reality optical system - Google Patents

Abstract

The present invention discloses a reflective virtual reality optical system, comprising an aperture (100), wherein a first lens (1) fixed relative to the aperture (100) and a second lens (2) movable relative to the aperture (100) are provided on one side of the aperture (100), a reflective element (3) and a display screen (200) are provided on the side of the second lens (2) away from the aperture (100), light emitted by the display screen (200) is reflected by the reflective element (3) and enters the second lens (2) and the first lens (1) before reaching the aperture (100), the first lens (1) is a biconvex aspheric lens with positive focal length, the second lens (2) is a meniscus aspheric lens with negative focal length, and the focal length of the reflective element (3) is 0. The present invention has a simple structure, high clarity, a large field of view, a small size, and a light weight.

Description

A reflective virtual reality optical system

【Technical field】

The invention relates to an optical system, more specifically to a reflective virtual reality optical system.

【Background technique】

At present, virtual reality (Virtual Reality, referred to as VR) and augmented reality (Augmented Reality, referred to as AR) have entered a period of rapid development. These devices are installed on the observer's head, so it must be compact and lightweight to reduce the load on the observer. For VR systems, a large field of view is very important. Only with a large field of view can the observer concentrate on observing high-quality dynamic images. Because the field of view, exit pupil diameter, and focal length of the VR system are mutually restricted It is very difficult to achieve a large field of view, a large exit pupil diameter and a short focal length at the same time. For this reason, lens groups and special lens solutions are the development trend of VR systems in the future. For the increasingly demanding VR field, products with clearer images and better user experience are needed.

Therefore, the present invention arises at the historic moment.

【Content of invention】

The purpose of the present invention is to overcome the deficiencies of the prior art and provide a reflective virtual reality optical system with simple structure, high definition, large viewing angle, small volume and light weight.

The present invention is achieved through the following technical solutions:

A reflective virtual reality optical system is characterized in that it includes a diaphragm 100, and one side of the diaphragm 100 is provided with a first lens 1 that is fixed relative to it and a second lens 2 that can move back and forth relative to it, so that The side of the second lens 2 far away from the diaphragm 100 is provided with a reflective element 3 and a display screen 200, and the light emitted by the display screen 200 is reflected by the reflective element 3 and enters the second lens 2 and the first lens 1 to reach the light. Diaphragm 100, the first lens 1 is a biconvex aspherical lens with positive refractive power, the second lens 2 is a meniscus aspherical lens with negative refractive power, and the light of the reflective element 3 Focus is 0.

The reflective virtual reality optical system as described above is characterized in that: from the stop 100 to the reflective element 3, the first surface of the first lens 1 is a hyperbolic aspheric surface, and the second surface is an elliptical aspheric surface. Spherical surface; the first surface of the second lens 2 is a circular aspheric surface, and the second surface is an oblate aspherical surface.

The reflective virtual reality optical system as described above is characterized in that: the reflective element 3 is a plane mirror or a reflective prism or a reflective free-form surface.

The reflective virtual reality optical system as described above is characterized in that the reflective element 3 is coated with multi-layer reflective films.

The above reflective virtual reality optical system is characterized in that: the first lens 1 and the second lens 2 are plastic lenses.

The above reflective virtual reality optical system is characterized in that: the display screen 200 is a liquid crystal display screen.

The reflective virtual reality optical system as described above is characterized in that: the shape of the aspheric surface of the first lens 1 and the second lens 2 satisfies the following equation: In the formula, the parameter c is the curvature corresponding to the radius, y is the radial coordinate, and its unit is the same as the lens length unit, and k is the coefficient of the conic conic curve; when the k coefficient is less than -1, the surface curve of the lens is double curve, when the k coefficient is equal to -1, the surface curve of the lens is a parabola; when the k coefficient is between -1 and 0, the lens surface curve is an ellipse, when the k coefficient is equal to 0, the lens surface curve The curve is circular, and when the k coefficient is greater than 0, the surface curve of the lens is oblate; α ₁ to α ₈ respectively represent the coefficients corresponding to each radial coordinate.

Compared with prior art, the present invention has following advantage:

1. The field of view of the present invention is very large, and the field of view can reach 120°, the 3D effect is more obvious, and there is a perfect feeling of being on the scene when watching images.

2. The optical system of the present invention is applicable to all experiencers, and the diopter can be adjusted by adjusting the position of the second lens. Any user can see the whole picture clearly by adjusting the diopter.

3. The present invention distributes the magnification reasonably, and the distortion is very small. After the image plane is enlarged, the sense of reality is guaranteed, which is more in line with the requirements of virtual reality.

4. The first lens and the second lens of the present invention are all made of plastic lenses, with compact structure, small volume, light system, and the weight of the whole finished product is less than 250g, which is very comfortable for the observer to wear.

5. The diameter of the entrance pupil of the present invention is large, the brightness of the displayed image has no obvious attenuation, the definition is very high, and the picture is uniform, no matter how the eyes are turned, the whole picture can be seen clearly, and the observer's visual fatigue is not easy to be caused.

【Description of drawings】

Fig. 1 is a schematic diagram of the present invention;

Fig. 2 is an optical path diagram of the optical system of the present invention.

【detailed description】

The present invention will be further described below in conjunction with accompanying drawing:

A reflective virtual reality optical system, comprising a diaphragm 100, one side of the diaphragm 100 is provided with a first lens 1 which is fixed relative to it and a second lens 2 which can move back and forth relative to it, and the second lens 2 is The side of the lens 2 away from the diaphragm 100 is provided with a reflective element 3 and a display screen 200. The light emitted by the display screen 200 is reflected by the reflective element 3 and then enters the second lens 2 and the first lens 1 and then reaches the diaphragm 100. The first lens 1 is a biconvex aspherical lens with positive refractive power, the second lens 2 is a meniscus aspheric lens with negative refractive power, and the refractive power of the reflective element 3 is 0 . When the optical system of the present invention is in use, the light propagates in reverse, and the actual light path is the light emitted by the miniature liquid crystal display screen 200, which is first reflected by the reflective element 3 and enters the second lens 2, then enters the first lens 1 through the second lens 2, and finally After passing through the first lens 1 and reaching the diaphragm 100, the diaphragm 100 is the observer's eyes.

For the convenience of design, the eye can be regarded as an ideal lens in the design, and at the same time, it is designed according to the idea of forward propagation of light, and the diaphragm in the design system is the observer. The first lens 1 is a plastic aspheric positive lens, so that all the light passing through the aperture of 100 apertures can enter the entire optical system smoothly, realizing a large field of view, and the field of view can reach 120°, realizing obvious 3D As a result, the first lens 1 can be made of a material with a low refractive index, and has a relatively large optical power, which mainly undertakes the effects of image magnification and image telephoto projection.

The refractive power of the first lens 1 is positive and fixed relative to the diaphragm 100 ; the refractive power of the second lens 2 is negative and can move back and forth relative to the diaphragm 100 . Therefore, using the principle of human eye imaging, when myopia users use it, the picture needs to move toward the eyes, adjust the position of the second lens 2, and compensate the picture movement caused by myopia, so that the optical system can always focus on the display screen 200 . Using the principle of reversible optical path, the light emitted by the display screen 200 can also enter the human eye and focus on the retina. People with different diopters can see the picture clearly as long as the second lens 2 is adjusted to an appropriate position, realizing the optical system internal Focus and diopter adjustment are suitable for all experiencers, which improves the limitation that the products on the market can only be used for users with normal vision.

The reflective element 3 may be a flat mirror, or a reflective prism or a reflective free-form surface, and the reflective element 3 is coated with a multi-layer reflective film. According to the design concept of forward propagation of light, the light projected through the second lens 2 is completely reflected by the reflective element 3 and enters the image plane, that is, the display screen 200 . Since the focal power of the reflective element 3 is 0, it will not generate aberration itself, nor will it affect the distribution of aberrations in the entire optical system. In addition, the reflective element 3 changes the position of the image plane of the optical system and transfers it to the first lens 1 and the side of the second lens 2, which greatly reduces the length of the entire optical system, making the structure compact and light.

The first lens 1 adopts a plastic aspheric positive lens with a low refractive index and high dispersion coefficient, and the second lens 2 adopts a plastic aspheric negative lens with a high refractive index and low dispersion. The positive and negative lenses are used together, and the positive lens produces The negative spherical aberration just compensates the positive spherical aberration produced by the negative lens, and corrects the spherical aberration and sinusoidal aberration of the optical system very well. The combination of high dispersion material and low dispersion material can not only correct the axial chromatic aberration of the system, but also correct the vertical axis chromatic aberration of the system, ensuring the image sharpness and color reproduction of the system. The first lens and the second lens in the optical system are used separately, which can well correct field curvature and distortion of the optical system.

From the diaphragm 100 to the direction of the reflective element 3, the first surface of the first lens 1 is a hyperbolic aspheric surface, and the second surface is an elliptical aspheric surface; the first surface of the second lens 2 is a circle The aspheric surface and the second surface are oblate aspheric surfaces. The entire optical system adopts four-sided aspheric surface. The aspheric surface not only produces small aberrations, but also balances the aberrations of the entire optical system well, so that the center and edge of the image surface of the optical system have quite high resolution.

The aspherical surface shapes of the first lens 1 and the second lens 2 satisfy the following equation: In the formula, the parameter c is the curvature corresponding to the radius, y is the radial coordinate, and its unit is the same as the lens length unit, and k is the coefficient of the conic conic curve; when the k coefficient is less than -1, the surface curve of the lens is double curve, when the k coefficient is equal to -1, the surface curve of the lens is a parabola; when the k coefficient is between -1 and 0, the lens surface curve is an ellipse, when the k coefficient is equal to 0, the lens surface curve The curve is circular, and when the k coefficient is greater than 0, the surface curve of the lens is oblate; α ₁ to α ₈ respectively represent the coefficients corresponding to each radial coordinate.

In the present invention, the first lens 1 , the second lens 2 and the reflection element 3 are all made of common plastic materials, which can effectively control the cost and reduce the weight of the system. The wide spectrum is used in the design, and the theoretical resolution of the design is much higher than the actual required value, which ensures the image sharpness and color reproduction.

Claims (7)

1. A reflection type virtual reality optical system is characterized in that: comprise diaphragm (100), described diaphragm (100) one side is provided with the first lens (1) that its position is fixed relative to it and relative to it can front and back A moving second lens (2), the side of the second lens (2) away from the diaphragm (100) is provided with a reflective element (3) and a display screen (200), and the light emitted by the display screen (200) The light is reflected by the reflective element (3), enters the second lens (2) and the first lens (1) and reaches the diaphragm (100), and the first lens (1) is a biconvex aspheric surface with positive refractive power As for the lens, the second lens (2) is a meniscus aspherical lens with negative refractive power, and the refractive power of the reflective element (3) is 0. 2. The reflective virtual reality optical system according to claim 1, characterized in that: from the diaphragm (100) to the direction of the reflective element (3), the first surface of the first lens (1) is The hyperbolic aspheric surface, the second surface is an elliptical aspheric surface; the first surface of the second lens (2) is a circular aspherical surface, and the second surface is an oblate aspherical surface. 3. The reflective virtual reality optical system according to claim 1 or 2, characterized in that: the reflective element (3) is a plane mirror or a reflective prism or a reflective free-form surface. 4. The reflective virtual reality optical system according to claim 1 or 2, characterized in that: the reflective element (3) is coated with a multi-layer reflective film. 5. The reflective virtual reality optical system according to claim 1 or 2, characterized in that: the first lens (1) and the second lens (2) are plastic lenses. 6. The reflective virtual reality optical system according to claim 1 or 2, characterized in that: the display screen (200) is a liquid crystal display screen. 7. The reflective virtual reality optical system according to claim 1, characterized in that: the aspheric surface shapes of the first lens (1) and the second lens (2) satisfy the following equation: In the formula, the parameter c is the curvature corresponding to the radius, y is the radial coordinate, and its unit is the same as the lens length unit, and k is the coefficient of the conic conic curve; when the k coefficient is less than -1, the surface curve of the lens is double curve, when the k coefficient is equal to -1, the surface curve of the lens is a parabola; when the k coefficient is between -1 and 0, the lens surface curve is an ellipse, when the k coefficient is equal to 0, the lens surface curve The curve is circular, and when the k coefficient is greater than 0, the surface curve of the lens is oblate; α ₁ to α ₈ respectively represent the coefficients corresponding to each radial coordinate.