WO2021217406A1

WO2021217406A1 - Optical diffusion sheet, light source apparatus, and distance measurement apparatus

Info

Publication number: WO2021217406A1
Application number: PCT/CN2020/087431
Authority: WO
Inventors: 兰洋; 沈健; 姚国峰
Original assignee: 深圳市汇顶科技股份有限公司
Priority date: 2020-04-28
Filing date: 2020-04-28
Publication date: 2021-11-04

Abstract

An optical diffusion sheet (10), a light source apparatus (20), and a distance measurement apparatus (30). The optical diffusion sheet (10) comprises a light homogenizing sheet (101) and one or more prisms (102); each of the one or more prisms (102) has at least one inclined surface which obliquely intersects a reference surface of the light homogenizing sheet (101) having an inclination angle not equal to 90 degrees; the reference surface is parallel to a plane having the minimum sum of distances from points on a light exit surface/a light incident surface of the light homogenizing sheet (101); the one or more prisms (102) are attached to the light exit surface/the light incident surface of the light homogenizing sheet (101); and the distribution density of the prisms (102) in the central region of the light homogenizing sheet (101) is greater than the distribution density of the prisms (102) in the marginal region of the light homogenizing sheet (101). Since each prism (102) on the optical diffusion sheet (10) has at least one inclined surface, light beams emitted by a light source (201) can be refracted toward a direction deviating from the center of the light beam, so that the light beams in the central region are reduced, and the light beams in the marginal region are increased; and when an image sensor (301) receives the light beams reflected back from an object to be measured, the light beams received by the image sensor (301) are evenly distributed while an optical signal in the marginal region is weakened.

Description

Optical diffuser, light source device and distance measuring device

Technical field

The embodiments of the present application relate to the field of optical technology, and in particular, to an optical diffuser, a light source device, and a distance measuring device.

Background technique

Image sensors are widely used in image acquisition, image recognition and other fields. Taking image acquisition as an example, the light emitted by the light source irradiates the object to be measured, is reflected by the object to be measured, is received by the image sensor, and forms an image. However, the edge of the image sensor is weaker than the light beam received at the center position. For example, the edge position of the image sensor has a deflection angle relative to the light beam received at the center position, and the front-illuminated image sensor has the problem of blocking light by the metal layer. This leads to weaker light beams in the edge area than in the center area; another example, because of the deflection angle, the law of cosine fourth power will also make the light signal received by the edge area weaker than the light signal received by the center area, which leads to the image sensor The generated image has uneven brightness distribution and poor image quality.

Summary of the invention

In view of this, one of the technical problems solved by the embodiments of the present application is to provide an optical diffuser, a light source device, and a distance measuring device to overcome the above-mentioned defects in the prior art.

In the first aspect, an embodiment of the present application provides an optical diffusion sheet, including: a light homogenizing sheet and one or more prisms;

Each prism of one or more prisms has at least one inclined plane that obliquely intersects with the reference plane of the homogenizing sheet and the inclination angle of the inclined plane is not equal to 90 degrees. The reference plane is parallel to the point on the light-emitting surface/light-incident surface of the homogenizing sheet The plane with the smallest sum of distances; one or more prisms are attached to the light incident surface and/or light output surface of the homogenizing sheet, and the prisms in the central area of the homogenizing sheet have a higher distribution density than the prisms in the edge area of the homogenizing sheet.

Optionally, in an embodiment of the present application, the inclination angle of each prism slope of the plurality of prisms is the same.

Optionally, in an embodiment of the present application, among the plurality of prisms, the oblique inclination angle of the prism in the central area of the homogenizing sheet is greater than the oblique inclination of the prism in the edge area of the homogenizing sheet.

Optionally, in an embodiment of the present application, the plurality of prisms are ring prisms with different inner diameters, and are sequentially nested and distributed on the light exit surface/light entrance surface of the homogenizing sheet to form a multi-ring structure, and the shape of the ring structure It is circular or polygonal.

Optionally, in an embodiment of the present application, a plurality of prisms are distributed in a manner of a plurality of prism groups, and the plurality of prisms included in each prism group are distributed on the light entrance surface/light exit surface of the homogenizing sheet to form a ring structure , A plurality of prism groups form a multi-ring structure with different inner diameters and sequentially nested and distributed, and the shape of the ring structure is a circle or a polygon.

Optionally, in an embodiment of the present application, each prism includes two inclined planes that intersect the reference plane, and the inclination angles of the inclined planes of the two inclined planes are the same.

Optionally, in an embodiment of the present application, each prism includes two inclined planes intersecting the reference plane, and the inclination angles of the inclined planes of the two inclined planes are different.

Optionally, in an embodiment of the present application, the prism is a triangular pyramid or a quadrangular pyramid.

Optionally, in an embodiment of the present application, the prism is a triangular prism with the side as the bottom surface and the light-emitting surface and/or the light-incident surface of the light homogenizing sheet are attached to each other.

Optionally, in an embodiment of the present application, the light-emitting surface of the light homogenizing sheet is a flat surface, and a plurality of prisms are distributed on the light-emitting surface; or the light-incident surface of the light homogenizing sheet is a flat surface, and a plurality of prisms are distributed on the light-incident surface. noodle.

Optionally, in an embodiment of the present application, the cross section of the bottom of the prism is larger than the cross section of the top of the prism, and the bottom of the prism is attached to the light exit surface/light entrance surface of the light homogenizing sheet.

Optionally, in an embodiment of the present application, the homogenizing sheet includes a substrate and at least one particle;

At least one particle is arranged inside the substrate, and the refractive index of the at least one particle is smaller than the refractive index of the substrate.

Optionally, in an embodiment of the present application, a plurality of prisms are attached to the light-emitting surface or the light-incident surface of the light homogenizing sheet through optical adhesive.

In a third aspect, an embodiment of the present application provides an optical diffusion sheet, including: a light homogenizing sheet and one or more prisms;

Each prism of one or more prisms has at least one inclined plane that obliquely intersects with the reference plane of the homogenizing sheet and the inclination angle of the inclined plane is not equal to 90 degrees. The reference plane is parallel to the point on the light-emitting surface/light-incident surface of the homogenizing sheet The plane with the smallest sum of distances; one or more prisms are attached to the light incident surface and/or light output surface of the homogenizing sheet, and the oblique angle of the prism in the central area of the homogenizing sheet is greater than the oblique angle of the prism in the edge area of the homogenizing sheet .

Optionally, in an embodiment of the present application, a plurality of prisms are uniformly distributed on the light-emitting surface/light-incident surface of the light homogenizing sheet.

Optionally, in an embodiment of the present application, among the plurality of prisms, the distribution density of the prisms in the central area of the homogenizing sheet is greater than the prisms in the edge area of the homogenizing sheet.

In a third aspect, an embodiment of the present application provides a light source device, including: a light source, a base, and an optical diffuser;

The optical diffusion sheet is the optical diffusion sheet described in the first aspect or any embodiment of the first aspect of the application, or the optical diffusion sheet is the optical diffusion sheet described in the second aspect or any embodiment of the second aspect of the application Optical diffuser.

The base forms a groove for accommodating the light source and the optical diffusion sheet; the light source is arranged at the bottom of the groove of the base; the optical diffusion sheet faces the light source and is arranged at the opening of the groove of the base.

Optionally, in an embodiment of the present application, the light source device further includes a driving circuit and a driving chip; the driving circuit is electrically connected to the light source, and the driving chip is electrically connected to the driving circuit.

Optionally, in an embodiment of the present application, the light source device further includes a photoelectric sensor; the photoelectric sensor is arranged in the groove of the base, and the photoelectric sensor is electrically connected to the driving chip.

Optionally, in an embodiment of the present application, the light source device further includes a glass cover plate; the glass cover plate is arranged on a side of the optical diffusion sheet away from the light source.

In a fourth aspect, an embodiment of the present application provides a distance measuring device, including an image sensor and the light source device described in the third aspect of the present application, wherein the light source device is used to emit detection light to the measurement target, and the image sensor is used to measure the distance from the measurement target. The reflected detection light determines the distance information of the measurement target.

In the optical diffuser, light source device, and distance measuring device provided by the embodiments of the present application, since a plurality of prisms are arranged on the optical diffuser, the prisms have at least one inclined plane that obliquely intersects with the reference plane of the homogenizing film and whose inclination angle is not equal to 90 degrees, The light beam emitted by the light source can be refracted in the direction away from the center of the light beam. Moreover, the prisms in the center area of the homogenizing sheet have a higher distribution density than the prisms in the edge area of the homogenizing sheet, so that the central area has more beam deflection and the edge area has less beam deflection. The light beam in the center area is reduced and the light beam in the edge area is increased. When the image sensor receives the light beam reflected from the object to be measured, the light signal in the edge area is weakened to make the light beam received by the image sensor evenly distributed.

Description of the drawings

Hereinafter, some specific embodiments of the embodiments of the present application will be described in detail in an exemplary but not restrictive manner with reference to the accompanying drawings. The same reference numerals in the drawings indicate the same or similar components or parts. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the attached picture:

FIG. 1 is a schematic diagram of the structure of an optical diffusion sheet provided in Embodiment 1 of the application;

Figure 1a is a schematic diagram of a reference plane provided by various embodiments of this application;

2 is a schematic diagram of the optical path of a light homogenizing sheet provided in Embodiment 1 of the application;

3a is a schematic diagram of an optical path of a prism structure on the surface of an optical diffusion sheet provided in Embodiment 1 of this application;

FIG. 3b is a schematic diagram of the optical path of another prism structure on the surface of the optical diffuser provided in the first embodiment of the application; FIG.

4 is a schematic cross-sectional view of the first optical diffuser provided in Embodiment 1 of the application;

5 is a schematic cross-sectional view of a second optical diffuser sheet provided in Example 1 of this application;

6 is a schematic cross-sectional view of a third optical diffuser provided in Embodiment 1 of the application;

FIG. 7a is a top view of the first optical diffusion sheet provided in Embodiment 1 of the application; FIG.

FIG. 7b is a top view of the second type of optical diffusion sheet provided in Embodiment 1 of the application; FIG.

FIG. 8a is a top view of a third optical diffusion sheet provided in Embodiment 1 of the application; FIG.

FIG. 8b is a top view of a fourth optical diffuser provided in Embodiment 1 of the application; FIG.

FIG. 9a is a top view of a fifth optical diffuser provided by Embodiment 1 of the application; FIG.

FIG. 9b is a three-dimensional enlarged schematic diagram of one of the prisms on the optical diffusion sheet shown in FIG. 9a;

FIG. 9c is a top view of the sixth optical diffuser provided in Embodiment 1 of the application; FIG.

9d is a three-dimensional enlarged schematic diagram of one of the prisms on the optical diffusion sheet shown in FIG. 9c;

10a is a schematic cross-sectional view of a fourth optical diffuser provided in Example 1 of the application;

10b is a schematic cross-sectional view of a fifth optical diffuser sheet provided in Example 1 of this application;

10c is a schematic cross-sectional view of a sixth optical diffuser provided in Embodiment 1 of the application;

FIG. 10d is a schematic cross-sectional view of a seventh optical diffuser provided in Embodiment 1 of the application; FIG.

FIG. 11 is a schematic cross-sectional view of an optical diffusion sheet provided in the second embodiment of the application; FIG.

12 is a schematic cross-sectional view of another optical diffuser provided in the second embodiment of the application;

FIG. 13 is a cross-sectional view of a light source device according to Embodiment 3 of the application;

14 is a cross-sectional view of another light source device provided in Embodiment 3 of the application;

FIG. 15 is a structural block diagram of a distance measuring device provided in the fourth embodiment of this application.

Detailed ways

The implementation of any technical solution of the embodiments of the present application does not necessarily need to achieve all the above advantages at the same time.

In order to enable those skilled in the art to better understand the technical solutions in the embodiments of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the description The embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art should fall within the protection scope of the embodiments of the present application.

The specific implementation of the embodiments of the present application will be further described below in conjunction with the drawings of the embodiments of the present application.

Example one,

The embodiment of the present application provides an optical diffusion sheet. FIG. 1 is a schematic structural diagram of an optical diffusion sheet provided in Embodiment 1 of the application; as shown in FIG. 1, the optical diffusion sheet 10 includes: a uniform light sheet 101 and one or Multiple prisms 102;

Each prism 102 of the one or more prisms 102 has at least one inclined plane that obliquely intersects with the reference plane of the homogenizing sheet 101 and the inclination angle of the inclined plane is not equal to 90 degrees. The plane with the smallest sum of point distances on the surface; one or more prisms 102 are attached to the light incident surface and/or light output surface of the homogenizing sheet 101, and the prism 102 in the central area of the homogenizing sheet 101 is larger than the edge area of the homogenizing sheet The prism 102 has a large distribution density.

Based on the optical diffuser shown in FIG. 1, the reference surface is exemplified. The plane with the smallest sum of the point distances on the light exit surface/light entrance surface of the homogenizing sheet 101 is defined as the reference surface, which is parallel to the reference surface. The plane is the reference plane, or the reference plane is the datum plane. If the light-emitting surface of the light homogenizing sheet 101 is a flat surface, the light-emitting surface can be used as a reference surface/reference surface; if the light-incident surface of the light homogenizing sheet 101 is a flat surface, the light-incident surface can be used as a reference surface/reference surface. If the light emitting surface of the light homogenizing sheet 101 is not flat, as shown in FIG. 1a, FIG. 1a is a schematic diagram of the reference surface provided by each embodiment of the application. In Figure 1a, the light-emitting surface is not flat. If the sum of the distances between a point on the light-emitting surface and a plane is the smallest, the plane is used as the reference plane, and the sum of the distances between at least one point on the light-emitting surface and the plane can be calculated. The more uniform a point is on the light-emitting surface and the more the number, the more accurate the reference plane is determined. In the same way, by selecting at least one point on the light incident surface, the plane with the smallest sum of the distance from the at least one point can be determined as the reference plane; you can also select at least one point on the light emitting surface and the light incident surface, The plane with the smallest sum of the distances of the at least one point is determined as the reference plane. Of course, this is only an exemplary description, and this application does not limit this.

Optionally, the closer the area to the center of the light homogenizing sheet 101 is, the greater the distribution density of the prisms 102 is. The distribution density of the prisms presents a gradual change. For example, taking the light-emitting surface of the light homogenizing sheet 101 as an example, the light-emitting surface of the light homogenizing sheet 101 is divided into at least one annular area with different inner diameters and the same center. In the annular area, the distribution density of the prisms 102 is greater. Of course, this is only an exemplary description, which does not mean that the application is limited to this.

It should be noted that, as shown in FIG. 2, FIG. 2 is a schematic diagram of the optical path of a homogenizing sheet provided in the first embodiment of the application. The homogenizing sheet 101 is used to scatter, reflect, refract, etc., the light beam entering the light beam. , So that the light beam emitted from the light homogenizing sheet 101 is uniformly distributed. For example, the light beam emitted from the light source into the light homogenizing sheet 101 will emit a uniform light beam after passing through the light homogenizing sheet 101. In FIG. 2, in order to better reflect the uniform light effect, a parallel beam is taken as an example for illustration, which does not mean that the application is limited to this, and point light sources are also applicable to this application. The structures that can achieve uniform distribution of the emitted light beams all belong to the light homogenizing sheet 101 mentioned in the present application. Here, two types of light homogenizing sheets 101 are listed to describe their effects.

Optionally, in an embodiment of the present application, for the first type of light homogenizing sheet 101, one of the light emitting surface and the light incident surface of the light homogenizing sheet 101 is flat, and the other surface is not flat, for example, uniform The light-emitting surface of the light sheet 101 is a flat surface, and the multiple prisms 102 are distributed on the light-emitting surface; or the light-incident surface of the light homogenizing sheet 101 is a flat surface, and the multiple prisms 102 are distributed on the light-incident surface. The uneven surface may be provided with a pattern or a frosted surface, and a plurality of prisms 102 are distributed on the flat surface of the light homogenizing sheet 101. It should be noted that the reference surface may be a flat surface of the light-emitting surface and the light-incident surface of the light homogenizing sheet 101. Of course, both the light-emitting surface and the light-incident surface of the light homogenizing sheet 101 may be flat surfaces; or, both the light-emitting surface and the light-incident surface of the light homogenizing sheet 101 may be uneven surfaces.

When the light beam passes through the uneven surface of the light homogenizing sheet 101, the distribution of the light beam entering the light homogenizing sheet 101 is uniform due to scattering, reflection and/or refraction.

Optionally, in another embodiment of the present application, the homogenizing sheet 101 includes a substrate 1011 and at least one particle 1012; the at least one particle 1012 is disposed inside the substrate 1011. Further optionally, the refractive index of the at least one particle 1012 may be less than the refractive index of the substrate 1011. Of the light-emitting surface and the light-incident surface of the substrate 1011, one surface is flat and the other surface is not flat. For example, the light-emitting surface of the substrate 1011 is a flat surface, and a plurality of prisms 102 are distributed on the light-emitting surface of the substrate 1011; or The light incident surface of 1011 is a flat surface. A plurality of prisms 102 are distributed on the light incident surface of the substrate 1011. The uneven surface may be patterned or a frosted surface. The plurality of prisms 102 are distributed on the flat surface of the substrate 1011. It should be noted that the reference surface may be a flat surface of the light-emitting surface and the light-incident surface of the substrate 1011. Of course, both the light-emitting surface and the light-incident surface of the substrate 1011 may be flat surfaces; or, both the light-emitting surface and the light-incident surface of the substrate 1011 may be uneven surfaces.

FIG. 2 takes the second type of light homogenizing sheet 101 as an example, but it does not mean that the application is limited to this. Taking the example shown in FIG. 2 as an example, the light beam emitted by the point light source is reflected and/or refracted by at least one particle 1012 in the homogenizing sheet 101, so that the emitted light beam is uniformly distributed. Exemplarily, the refractive index of at least one particle 1012 may be 1.2, and the refractive index of the substrate 1011 may be 1.5. Of course, this is only an exemplary description and does not mean that the application is limited to this.

The multiple prisms 102 can cause the light beams that enter the prism 102 to be refracted by the oblique surface of the prism 102 and then diffuse outward. In this application, the axis perpendicular to the reference plane and passing through the center of the light homogenizing sheet 101 is taken as the central axis. In this application, outward diffusion refers to the light beam spreading away from the central axis.

It should be noted that the refractive index of the prism 102 is greater than the refractive index of air. For example, the refractive index of the prism 102 may be 1.2, and the refractive index of air may be 1.

Optionally, in an embodiment of the present application, the cross section of the bottom of the prism 102 is larger than the cross section of the top of the prism 102, and the bottom of the prism 102 is attached to the light exit surface/light entrance surface of the light homogenizing sheet 101. Optionally, a plurality of prisms 102 may be fixed on the light homogenizing sheet 101, or the prism 102 and the light homogenizing sheet 101 may be integrally formed. The materials of the light homogenizing sheet 101 and the prism 102 may be the same or different, which is not limited in this application. .

The inclined surface of the prism 102 may be facing the central axis or facing away from the central axis. In this application, facing the central axis means that the vertical line of the inclined surface extends toward the air side close to the central axis, and the opposite to the central axis refers to the vertical line of the inclined surface. Extend to the air side away from the central axis. For example, when the prism 102 is located on the light emitting surface of the light homogenizing sheet 101, extending to the air side means extending upward, and the light emitting surface can be used as the upper surface of the light homogenizing sheet 101. When the prism 102 is located on the light entering surface of the light homogenizing sheet 101, The extension of the air side is the extension downward, and the light incident surface can be used as the lower surface of the light homogenizing sheet 101. Here, two orientations of the prism 102 are taken as an example to describe the optical path of the prism 102.

As shown in Figs. 3a and 3b, Figs. 3a and 3b are schematic diagrams of the optical path of the prism structure on the surface of the optical diffuser provided in the first embodiment of the present application. In Figure 3a, the inclined surface of the prism 102 faces the central axis. Because the refractive index of the prism 102 is greater than that of air, the light beam is deflected away from the normal of the inclined surface; The direction of the line is deflected, but it will also be close to the central axis. After crossing the convergent point with the central axis, the beam moves towards the far central axis. Therefore, regardless of whether the slope of the prism 102 faces the central axis or not, the prism 102 can make the light beam away from the central area and spread toward the edge area, so that the light beam in the central area decreases and the light beam in the edge area increases. The greater the distribution density of the prism, the greater the deflection of the light beam in the central area and the less the deflection of the light beam in the edge area, which makes the light beam in the central area less than the light beam in the edge area. The light signal in the center area is weak, and the light signal in the edge area is strong. Under the influence of the cosine fourth power law and other reasons, the light signal in the edge area of the beam will be reduced, so that the two phases are superimposed, so that the image sensor finally receives a uniform distribution The light beam improves the imaging quality of the image sensor.

It should be noted that because the refractive index of the prism 102 is greater than the refractive index of air, total reflection will be formed at a specific angle. To avoid total reflection, the tilt angle of the prism 102 can be set. Optionally, in the present application In one embodiment, the inclination angle of the oblique surface of the prism 102 is greater than 0° and less than a predetermined angle. The oblique surface inclination angle of the prism 102 is the angle formed by the oblique surface of the prism 102 and the reference surface, and the predetermined angle is less than 90°. For example, if the refractive index of the prism 102 is 1.2 and the refractive index of air is 1, total reflection occurs when the tilt angle of the prism 102 is 56.4°. The tilt angle of the prism 102 can be set to (0,56.4), of course This is only an exemplary description, and does not mean that the application is limited to this.

Based on the description of the orientation of the inclined surface of the prism 102 and the light path in FIGS. 3a and 3b, here are two specific implementations to illustrate the distribution of the multiple prisms 102. Of course, the prism 102 may include one inclined plane or multiple inclined planes. Optionally, in an embodiment of the present application, each prism 102 includes two inclined planes intersecting the reference plane, and the angles of the inclined planes of the two inclined planes are the same; In another embodiment, each prism 102 includes two inclined surfaces that intersect the reference plane, and the inclination angles of the inclined surfaces of the two inclined surfaces are different. This application does not restrict this.

Optionally, in an embodiment of the present application, when the prism 102 includes at least two inclined surfaces, the inclination angles of the inclined surfaces of the at least two inclined surfaces are the same. Optionally, in another embodiment of the present application, when the prism 102 includes at least two inclined surfaces, the inclination angles of the inclined surfaces of the at least two inclined surfaces are different. In the same prism 102, the slopes of the slopes have the same or different slope angles, which can reduce the beam in the central area and increase the beam in the edge area. If the slopes of the slopes have the same slope, the direction of beam deflection is consistent, so that the beam distribution conforms to the prism 102. The law of distribution, if the inclination angles of the slopes are different, the beam in the central area can be further reduced, and the beam in the edge area can be increased. Of course, this is only an exemplary description, which does not mean that the application is limited to this.

Optionally, in an embodiment of the present application, the inclination angle of the oblique surface of each prism 102 of the plurality of prisms 102 is the same, and the oblique surface inclination angle of the prism 102 is the angle formed by the oblique surface of the prism 102 and the reference plane.

Exemplarily, in FIG. 1, the prism 102 includes an inclined surface, and the inclined surface of the inclined surfaces of the prism 102 has the same inclination angle as an example for illustration. Correspondingly, in an optional implementation manner, as shown in FIG. 4, FIG. 4 is a schematic cross-sectional view of the first optical diffusion sheet provided in Embodiment 1 of the application, and FIG. 4 takes each prism 102 including two inclined surfaces as For example, the inclination angles of the two inclined surfaces included in each prism 102 are the same; the distribution density of the prisms 102 in the central area of the homogenizing sheet 101 is greater than that of the prisms 102 in the edge area of the homogenizing sheet 101.

The distribution of the prisms 102 in the central area is tighter than the distribution of the prisms 102 in the edge area, so that more light beams are deflected in the edge direction, and therefore, the light beams in the central area can be reduced.

Optionally, in an embodiment of the present application, among the plurality of prisms 102, the oblique inclination angle of the prism in the central area of the homogenizing sheet 101 is greater than the oblique inclination of the prism in the edge area of the homogenizing sheet 101. Further, the closer the area to the center of the homogenization sheet, the greater the slope angle of the prism 102, and the closer the area to the edge of the homogenization sheet, the smaller the slope angle of the prism 102. The slope angle of the prism 102 is the slope of the prism 102 and the reference plane. The angle formed. For example, as shown in FIG. 5, FIG. 5 is based on the optical diffuser shown in FIG. The prism 102 in the central area of the light sheet has the characteristic that the slope angle is larger. In the example shown in FIG. In the area closer to the center, the slope of the prism 102 has a larger inclination angle. Because the central area prism 102 has a high distribution density, the number of beams deflected in the central area is large, and because the inclined plane of the central area prism 102 has a large inclination angle, the light beam in the central area is deflected at a larger angle, which further reduces the central area. beam. Based on the optical diffuser shown in FIG. 5, FIG. 6 further shows the case where the prism 102 includes two inclined planes. In FIG. 6, each prism 102 includes two inclined planes. Larger, the closer to the central area, the greater the distribution density of the prism 102. Of course, this is only an exemplary description, which does not mean that the application is limited to this.

Based on the description of the orientation of the inclined surface of the prism 102 and the light path in FIGS. 3a and 3b, here, the distribution of the prism 102 on the surface of the homogenizing sheet 101 is described from a top-view perspective. It should be noted that in a top-view perspective , Focusing on the shape of the prism distribution, which can be combined with the inclination angle and distribution density of the prism in the cross-sectional view, which is not limited in this application.

Optionally, in an embodiment of the present application, the multiple prisms 102 are distributed in a manner of multiple prism 102 groups, and the multiple prisms 102 included in each prism 102 group are located on the light incident surface/light output surface of the light homogenizing sheet 101. The surface distribution forms a ring structure, and a plurality of prisms 102 groups form a multi-ring structure with different inner diameters and sequentially nested and distributed, and the shape of the ring structure is a circle or a polygon.

For example, as shown in FIG. 7a, the light-emitting surface and the light-incident surface of the light homogenizing sheet 101 are circular, and the ring structure formed by a plurality of prisms 102 may be a ring with the center of the light-emitting surface of the light homogenizing sheet 101 as the center (of course, here is Taking the light exit surface as an example, if the prisms 102 are distributed on the light entrance surface of the light homogenizing sheet 101, the ring structure is a ring centered on the light entrance surface of the light homogenizing sheet 101); for another example, as shown in FIG. 7b, the light homogenizing sheet 101 The light-emitting surface and the light-incident surface of are square, and the ring structure formed by the plurality of prisms 102 may be a square with the center of the light-emitting surface of the light homogenizing sheet 101 as the center. Of course, this is only an exemplary description, which does not mean that the application is limited to this. In Figures 7a and 7b, only one ring structure is shown. The prism 102 can be distributed to form multiple rings nested together. As shown in Figures 8a and 8b, two rings are nested The distribution status together, of course, is only an exemplary description here, and does not mean that the application is limited to this.

Combining the distribution of the prisms 102 shown in Figs. 7a and 7b, when each prism 102 includes multiple inclined surfaces, the distribution effect will be different.

Optionally, in an embodiment of the present application, the shape of the prism 102 is a triangular pyramid or a quadrangular pyramid; Or, the shape of the prism 102 is a circular prism whose side surface is attached to the light homogenizing sheet 101.

For example, FIG. 8a is a top view of an optical diffusion sheet provided in Embodiment 1 of the present application. In FIG. 8a, the shape of each prism 102 is a triangular pyramid. For another example, FIG. 8b is a top view of an optical diffusion sheet provided in Embodiment 1 of the present application. In FIG. 8b, the shape of each prism 102 is a quadrangular pyramid.

As another example, as shown in FIGS. 9a and 9b, FIG. 9a is a top view of an optical diffuser sheet provided in Example 1 of this application, FIG. 9b is a three-dimensional view of a prism provided in Example 1 of this application, and FIG. 9b is a diagram The three-dimensional schematic diagram of a ring structure in 9a, the shape of each prism 102 is a triangular prism, and the side surface of each prism is attached to the light homogenizing sheet 101.

Optionally, in another embodiment of the present application, the plurality of prisms 102 are ring-shaped prisms 102 with different inner diameters, and are sequentially nested and distributed on the light exit surface/light entrance surface of the homogenizing sheet to form a multi-ring structure. The shape of the structure is circular or polygonal. As shown in Figure 9c and Figure 9d, Figure 9c is a top view of an optical diffusion sheet provided in Example 1 of this application, Figure 9d is a perspective view of an annular prism provided in Example 1 of this application, and Figure 9d is in Figure 9c A schematic diagram of the three-dimensional structure of a ring prism, it can also be said that the prisms 102 in a ring structure are connected together to form a ring prism.

Of course, the above is only an exemplary description, and does not mean that the application is limited to this.

A plurality of prisms 102 may be distributed above the light homogenizing sheet 101 (above the light exit surface); or, a plurality of prisms 102 may be distributed below the light homogenizing sheet 101 (below the light incident surface); or, a plurality of prisms 102 may be Distributed above and below the homogenizing sheet 101. The plurality of prisms 102 may be fixed on the light-emitting surface and/or the light-incident surface of the light homogenizing sheet 101, or a gap of a predetermined distance is left between the plurality of prisms 102 and the light homogenizing sheet 101.

As shown in Figures 10a-10d, in Figure 10a, the light-emitting surface of the light homogenizing sheet 101 is flat, but the light-incident surface is uneven, and a plurality of prisms 102 are distributed on the light-emitting surface of the light homogenizing sheet 101; in Figure 10b, the light homogenizing sheet 101 emits light The light-emitting surface and the light-incident surface are flat, and a plurality of prisms 102 are distributed on the light-emitting surface and the light-incident surface of the light homogenizing sheet 101; in FIG. On the light emitting surface of the light homogenizing sheet 101, a gap of a preset distance is left between the prism 102 and the light emitting surface of the light homogenizing sheet 101; in FIG. 102 is distributed above the light-emitting surface and below the light-incident surface of the homogenizing sheet 101. Optionally, a plurality of prisms 102 are attached to the light-emitting surface or light-incident surface of the light homogenizing sheet 101 by optical adhesive.

Of course, FIGS. 10a to 10d only exemplarily illustrate the distance relationship between the light homogenizing sheet 101 and the prism 102, and it does not mean that the application is limited to this.

In the optical diffuser provided by the embodiment of the present application, since a plurality of prisms are arranged on the optical diffuser, the prisms have at least one inclined plane that obliquely intersects with the reference plane of the homogenizing film and whose inclination angle is not equal to 90 degrees, which can direct the light beam emitted by the light source to Refraction away from the center of the light beam, and the distribution density of the prisms in the center area of the homogenizing sheet is higher than that of the prisms in the edge area of the homogenizing sheet, which makes the central area more deflection of the light beam and less light deflection in the edge area, which reduces the light beam in the central area. The edge area light beam is added. When the image sensor receives the light beam reflected back from the object to be measured, the light signal in the edge area is weakened to make the light beam received by the image sensor evenly distributed.

Embodiment two

In combination with the optical diffuser described in the first embodiment, the second embodiment of the present application provides a light source device, as shown in FIG. 11, which is a cross-sectional view of an optical diffuser provided by the second embodiment of the application. The diffuser sheet has the same composition structure as the optical diffuser sheet 10 described in the first embodiment. The difference is that the distribution of the prisms 102 is different. Therefore, the same components are indicated by the same reference numerals. The various implementations described in the first embodiment The method and explanation are also applicable to the second embodiment. As shown in FIG. 11, the optical diffusion sheet 10 includes: a light homogenizing sheet 101 and one or more prisms 102;

Each prism 102 of the one or more prisms 102 has at least one inclined plane that obliquely intersects with the reference plane of the homogenizing sheet 101 and the inclination angle of the inclined plane is not equal to 90 degrees. The plane with the smallest sum of point distances on the surface; one or more prisms 102 are attached to the light incident surface and/or light output surface of the homogenizing sheet 101, and the inclination angle of the prism 102 in the central area of the homogenizing sheet 101 is greater than that of the uniform light The inclination angle of the prism 102 in the edge area of the sheet 101.

Optionally, in an embodiment of the present application, a plurality of prisms 102 are evenly distributed on the light-emitting surface/light-incident surface of the light homogenizing sheet 101. As shown in FIG. 11, in order to better represent the change of the tilt angle, the distribution of the prisms is uniformly distributed. Of course, FIG. 11 is only an exemplary illustration, and does not mean that the application is limited to this. As shown in FIG. 12, FIG. 12 is based on FIG. 11 and shows a case where the prism 102 includes two inclined surfaces. In FIG. 12, the inclined angles of the two inclined surfaces of each prism 102 are the same, and the prisms 102 are evenly distributed. Of course, this is only an exemplary description. The distribution of the prisms 102 in the embodiment is also applicable to the second embodiment, which will not be repeated here.

Optionally, in another embodiment of the present application, among the plurality of prisms 102, the distribution density of the prisms 102 in the central area of the light homogenizing sheet 101 is greater than that of the prisms 102 in the edge area of the light homogenizing sheet 101. Further optionally, among the plurality of prisms 102, the closer the area to the center of the light homogenizing sheet 101, the greater the slope angle of the prism 102, and the closer the area to the edge of the light homogenizing sheet 101, the smaller the slope angle of the prism 102 is. The cross-sectional view can be referred to as shown in FIG. 5, which will not be repeated here.

In the optical diffuser provided by the embodiments of the present application, since a plurality of prisms are arranged on the optical diffuser, the prisms have at least one inclined surface, which can refract the light beam emitted by the light source in a direction deviating from the center of the light beam. The greater the tilt angle of the prism, the greater the deflection angle of the beam in the central area, greatly reduces the beam in the central area and increases the beam in the edge area. When the image sensor receives the beam reflected from the object to be measured, the light signal in the edge area is weakened. Bottom makes the light beam received by the image sensor evenly distributed.

Embodiment three

Based on the optical diffuser described in the first embodiment, an embodiment of the present application provides a light source device, as shown in FIG. 13, which is a cross-sectional view of a light source device provided by an embodiment of the application, and the light source device 20 includes ：Light source 201, base 202 and optical diffuser 10;

The optical diffuser 10 is the optical diffuser described in any embodiment of the application; the base 202 forms a groove for accommodating the light source 201 and the optical diffuser; the light source 201 is arranged at the bottom of the groove of the base 202; the optical diffuser The sheet faces the light source 201 and is arranged at the opening of the groove of the base 202.

It should be noted that the light source 201 in this application may be a visible light source 201 or an invisible light source 201. For example, the light source 201 may be an infrared light source 201. For another example, the light source 201 may be a vertical cavity surface emitting laser (Vertical Cavity Surface Emitting Laser). Surface-Emitting Laser, VCSEL). Of course, this is only an exemplary description. The base 202 may be an opaque material, and the optical diffusion sheet may be fixed on the side wall of the base 202. It should be noted that the base is only a simplified term. Specifically, it can be a ceramic base, a metal bracket, a composite package frame formed by a combination of a metal substrate and plastic or other materials, and various structures for installing or encapsulating the light source.

Optionally, in an embodiment of the present application, as shown in FIG. 14, the light source device 20 further includes a driving circuit 203 and a driving chip 204; the driving circuit 203 is electrically connected to the light source 201, and the driving chip 204 is electrically connected to the driving circuit 203 .

It should be noted that the driving chip 204 is used to transmit signals through the driving circuit 203 to control the power supply. For example, the driving chip 204 outputs a control signal to the control circuit, and the control circuit transmits the control signal to the light source 201 to realize the light intensity control of the light source 201. Of course, this is only an exemplary description.

Optionally, in an embodiment of the present application, as shown in FIG. 14, the light source device 20 further includes a photoelectric sensor 205; the photoelectric sensor 205 is disposed in the groove of the base 202, and the photoelectric sensor 205 and the driving chip 204 Electric connection.

The photo sensor 205 is used to convert the detected light signal into an electrical signal and output the electrical signal. For example, the photo sensor 205 may be a photo diode (PD). The photoelectric sensor 205 can detect the light signal emitted by the light source, convert the light signal into an electrical signal and transmit it to the drive chip 204, and the drive chip 204 judges whether the light signal intensity of the light source 201 meets the system requirements according to the electrical signal transmitted by the photoelectric sensor 205 or Whether it is necessary to control and adjust, of course, this is only an exemplary description, which does not mean that the application is limited to this.

Optionally, in an embodiment of the present application, as shown in FIG. 14, the light source device 20 further includes a glass cover plate 206; the glass cover plate 206 is arranged on the side of the optical diffusion sheet away from the light source 201.

In the light source device provided by the embodiment of the present application, since a plurality of prisms are arranged on the internal optical diffusion sheet, the prisms have at least one inclined plane that obliquely intersects with the reference plane of the homogenizing sheet and the inclination angle of the inclined plane is not equal to 90 degrees. Refraction in the direction away from the center of the beam, and the prisms in the center area of the homogenizing sheet have a higher distribution density than the prisms in the edge area of the homogenizing sheet, which makes the central area more deflection of the beam and less beam deflection in the edge area, reducing the central area of the beam. , The edge area light beam is added. When the image sensor receives the light beam reflected back from the object to be measured, the light signal in the edge area is weakened to make the light beam received by the image sensor evenly distributed.

Embodiment four

Based on the light source device described in the third embodiment, an embodiment of the present application provides a distance measuring device. As shown in FIG. 15, the distance measuring device 30 includes an image sensor 301 and the light source device 20 described in any embodiment of the present application. , Where the light source device 20 is used to emit detection light to the measurement target, and the image sensor 301 is used to determine the distance information of the measurement target according to the detection light reflected from the measurement target.

In the distance measuring device provided by the embodiments of the present application, since a plurality of prisms are arranged on the optical diffusion sheet inside, the prisms have at least one inclined plane that obliquely intersects with the reference plane of the homogenizing sheet and the inclination angle of the inclined plane is not equal to 90 degrees, which can emit light from the light source. The beam is refracted in a direction away from the center of the beam, and the prisms in the center area of the homogenizing sheet have a higher distribution density than the prisms in the edge area of the homogenizing sheet, which makes the central area more deflection of the beam, and the edge area less deflection, reducing the central area. The light beam increases the edge area light beam. When the image sensor receives the light beam reflected back from the object to be measured, the light signal in the edge area is weakened to make the light beam received by the image sensor evenly distributed.

The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the difference from other embodiments. In particular, as for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and for related parts, please refer to the part of the description of the method embodiment.

The above descriptions are only examples of the present application, and are not used to limit the present application. For those skilled in the art, this application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included in the scope of the claims of this application.

Claims

An optical diffusion sheet, characterized in that it comprises: a light homogenizing sheet and one or more prisms;

Each prism of the one or more prisms has at least one inclined plane that obliquely intersects with the reference plane of the homogenizing sheet and the inclination angle of the inclined plane is not equal to 90 degrees, and the reference plane is parallel to the light output of the homogenizing sheet The plane with the smallest sum of point distances on the surface/light incident surface;

The one prism or the plurality of prisms are attached to the light incident surface and/or the light output surface of the light homogenizing sheet, and the prisms in the central area of the light homogenizing sheet have a higher distribution density than the prisms in the edge area of the light homogenizing sheet Big.
The optical diffuser according to claim 1, wherein:

The inclination angle of each of the prisms of the plurality of prisms is the same.
The optical diffuser according to claim 1, wherein:

In the plurality of prisms, the slope angle of the prism in the central area of the light homogenizing sheet is greater than the slope angle of the prism in the edge area of the light homogenizing sheet.
The optical diffuser according to any one of claims 1 to 3, wherein:

The plurality of prisms are ring prisms with different inner diameters, and are sequentially nested and distributed on the light exit surface/light entrance surface of the homogenizing sheet to form a multi-ring structure, and the shape of the ring structure is a circle or a polygon.
The optical diffusion sheet according to any one of claims 1 to 3, wherein the plurality of prisms are distributed in a manner of a plurality of prism groups, and the plurality of prisms included in each prism group are arranged on the light homogenizing sheet The light-incident surface/light-exit surface distribution forms a ring structure, the plurality of prism groups form a multi-ring structure with different inner diameters and sequentially nested and distributed, and the shape of the ring structure is a circle or a polygon.
The optical diffuser according to any one of claims 1 to 5, wherein:

Each of the prisms includes two inclined planes intersecting with the reference plane, and the inclination angles of the inclined planes of the two inclined planes are the same.
The optical diffuser according to any one of claims 1 to 5, wherein:

Each of the prisms includes two inclined planes intersecting the reference plane, and the inclination angles of the inclined planes of the two inclined planes are different.
The optical diffusion sheet according to any one of claims 1-8, wherein the shape of the prism is a triangular pyramid or a quadrangular pyramid.
The optical diffusion sheet according to any one of claims 1-8, wherein the prism is a triangular prism whose side surface is attached to the light-emitting surface and/or the light-incident surface of the light homogenizing sheet.
The optical diffuser according to any one of claims 1-10, wherein the light emitting surface of the light homogenizing sheet is a flat surface, and the plurality of prisms are distributed on the light emitting surface; or the light homogenizing sheet The light incident surface is a flat surface, and the multiple prisms are distributed on the light incident surface.
The optical diffuser according to any one of claims 1-11, wherein:

The cross section of the bottom of the prism is larger than the cross section of the top of the prism, and the bottom of the prism is attached to the light exit surface/light entrance surface of the light homogenizing sheet.
The optical diffusion sheet according to any one of claims 1-12, wherein the homogenizing sheet comprises a substrate and at least one particle;

The at least one particle is disposed inside the substrate, and the refractive index of the at least one particle is less than the refractive index of the substrate.
The optical diffuser according to any one of claims 1-13, wherein:

The plurality of prisms are bonded to the light-emitting surface or the light-incident surface of the light homogenizing sheet through optical adhesive.
An optical diffusion sheet, characterized in that it comprises: a light homogenizing sheet and one or more prisms;

Each prism of the one or more prisms has at least one inclined plane that obliquely intersects with the reference plane of the homogenizing sheet and the inclination angle of the inclined plane is not equal to 90 degrees, and the reference plane is parallel to the light output of the homogenizing sheet The plane with the smallest sum of point distances on the surface/light incident surface;

The one prism or the plurality of prisms are attached to the light incident surface and/or the light output surface of the light homogenizing sheet, and the inclination angle of the prism in the central area of the light homogenizing sheet is larger than that of the edge area of the light homogenizing sheet The tilt angle of the prism.
The optical diffuser according to claim 1, wherein:

The plurality of prisms are evenly distributed on the light-emitting surface/light-incident surface of the light homogenizing sheet.
The optical diffuser according to claim 1, wherein:

Among the plurality of prisms, the prisms in the central area of the light homogenizing sheet have a higher distribution density than the prisms in the edge area of the light homogenizing sheet.
A light source device, characterized by comprising: a light source, a base and an optical diffuser;

The optical diffuser is the optical diffuser according to any one of claims 1-13, or the optical diffuser is the optical diffuser according to any one of claims 14-16;

The base forms a groove for accommodating the light source and the optical diffuser; the light source is arranged at the bottom of the groove; the optical diffuser faces the light source and is arranged in the groove Of the opening.
The device according to claim 17, wherein the light source device further comprises a driving circuit and a driving chip;

The driving circuit is electrically connected with the light source, and the driving chip is electrically connected with the driving circuit.
The device according to claim 18, wherein the light source device further comprises a photoelectric sensor;

The photoelectric sensor is arranged in the groove of the base, and the photoelectric sensor is electrically connected with the driving chip.
The device according to any one of claims 17-19, wherein the light source device further comprises a glass cover plate;

The glass cover plate is arranged on a side of the optical diffusion sheet away from the light source.
A distance measuring device, characterized by comprising an image sensor and the light source device according to any one of claims 17-20, wherein the light source device is used to emit detection light to the measurement target, and the image sensor is used to The detection light reflected from the measurement target determines the distance information of the measurement target.