Optical element, and projection device using the same

Abstract

To provide an optical element placed between a light source and an optical deflector for reflecting and deflecting incident light in two dimensions capable of solving the problem of reduction in projection angle and optical aberration generated by optical elements.SOLUTION: The optical element placed between a light source and an optical deflector that reflects and deflects incident light in two dimensions includes: a first region that allows light from a light source to incident and to output the an optical deflector; and a second region in which light reflected and deflected in two dimensions by the optical deflector is incident and output to the outside, and that is different from the first region. At least one of the entrance and exit sides of the first region, and the entrance and exit sides of the second region, is provided with an optical surface that has different optical effects.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to an optical element and a projection device using the same. [Background technology]

[0002] There is known a projection device that includes a light source, an optical deflector that two-dimensionally deflects incident light, and an optical element (prism) disposed between the light source and the optical deflector (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6457185 Summary of the Invention [Problem to be solved by the invention]

[0004] However, although Patent Document 1 takes into consideration measures against stray light using optical elements, it does not give sufficient consideration to the reduction in the projection angle of view and optical aberration caused by the optical elements.

[0005] The present disclosure has been made to solve these problems, and aims to provide an optical element that effectively suppresses various aberrations, makes it easier to obtain a high-quality projected image, and suppresses the reduction in the angle of view caused by the optical element, and a projection device using the same. [Means for solving the problem]

[0006] The optical element according to the present disclosure is an optical element disposed between a light source and an optical deflector that reflects incident light and deflects it two-dimensionally, and comprises a first region into which light from the light source is incident and which emits it to the optical deflector, and a second region different from the first region into which light that has been reflected by the optical deflector and deflected two-dimensionally is incident and emitted to the outside, and optical surfaces having different optical functions are provided on the entrance side and exit side of the first region and on at least one of the entrance side and exit side of the second region.

[0007] In the optical element, the optical surface may be an optical surface having a refractive power.

[0008] In the optical element, at least the second region may be provided on the exit side with an optical surface having a refractive power.

[0009] In the optical element, at least an optical surface having a refractive power may be provided on the incident side of the first region.

[0010] In the optical element, at least the optical effects of the entrance side of the first region and the exit side of the second region may be different from each other.

[0011] The optical element may be made of at least two types of materials.

[0012] A projection device according to the present disclosure includes a light source, an optical deflector that reflects and two-dimensionally deflects incident light, and the optical element described above. Effect of the Invention

[0013] The present disclosure makes it possible to provide an optical element that effectively suppresses various aberrations, makes it easier to obtain a high-quality projected image, and suppresses narrowing of the angle of view caused by the optical element, and a projection device using the same. [Brief description of the drawings]

[0014] [Figure 1]FIG. 1 is a schematic diagram of a projection device 10. [Diagram 2] FIG. 1 is a perspective view of a projection device 10. [Diagram 3] 3 is a cross-sectional view taken along line AA in FIG. 2. [Figure 4] 1 is a first modified example of the optical element 50. [Diagram 5] (a) Modification 2 of the optical element 50; (b) Modification 3 of the optical element 50. [Figure 6] (a) Modification 4 of the optical element 50 , and (b) Modification 5 of the optical element 50 . [Figure 7] 6 is a sixth modified example of the optical element 50. [Figure 8] 7 is a seventh modified example of the optical element 50. [Figure 9] 8 shows an eighth modified example of the optical element 50. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, a projection device 10 to which an optical element 50 according to an embodiment of the present disclosure is applied will be described with reference to the accompanying drawings. In each drawing, corresponding components are given the same reference numerals, and duplicated descriptions will be omitted.

[0016] FIG. 1 is a schematic diagram of a projection device 10, FIG. 2 is a perspective view of the projection device 10, and FIG. 3 is a cross-sectional view taken along line AA in FIG.

[0017] The projection device 10 is a laser scanning projector (or a picoprojector) that forms (projects) an image on a screen S by a laser beam that is two-dimensionally deflected (two-dimensionally scanned).

[0018] 1 and 2, the projection device 10 includes a light source 20, a reflecting surface 30 (omitted from FIG. 1), an optical deflector 40, an optical element 50, and a control device 60. The light source 20, the reflecting surface 30, the optical deflector 40, the optical element 50, and the control device 60 are arranged in a housing 70. The housing 70 is a rectangular parallelepiped housing, and one surface (side surface) thereof is formed with a light exit port 71 through which the laser beam Ray2 reflected and two-dimensionally deflected by the optical deflector 40 exits.

[0019] The light source 20 is a light source module that emits a single laser beam Ray1 (light ray) that is a combination (combination) of laser beams of three primary colors (RGB). The laser beam Ray1 emitted by the light source 20 is reflected by the reflecting surface 30, passes through the optical element 50, and enters the optical deflector 40 (mirror section 41).

[0020] The reflecting surface 30 is disposed on the optical path of the laser beam Ray1 emitted by the light source 20, but is not an essential component and may be present, or may be omitted if unnecessary.

[0021] 3, the optical deflector 40 is disposed on the opposite side of the optical element 50 from the light exit port 71. In this case, the optical deflector 40 is disposed so that the laser beams Ray1 and Ray2 transmitted through the optical element 50 do not overlap each other.

[0022] It is desirable that the distance L1 between the optical deflector 40 and the optical element 50 is as short as possible, and it is desirable that the optical deflector 40 is disposed in the vicinity of the optical element 50 with a space therebetween. In this way, it is possible to reduce the size of the optical element 50, and therefore the size of the projection device 10.

[0023] The optical element 50 is made of a transparent resin such as acrylic or polycarbonate, or glass. The optical element 50 is formed by bonding, for example, a trapezoidal prism including a first surface 51 and a second surface 52 that are not parallel to each other, and a transparent body 53 between the first surface 51 and the second surface 52, and a lens portion having refractive power indicated by reference numerals 51a and 51b. Since the optical path for guiding the light beam to the light deflector 40 and from the light deflector 40 to the projection surface can be realized by a single optical element 50, it is possible to reduce the size of the projection device 10. Note that the optical element 50 is not limited to a trapezoidal prism and a lens portion having refractive power, and both may be molded integrally.

[0024] Hereinafter, the portion of the optical element 50 where the laser beam from the light source 20 (laser beam Ray1 reflected by the reflecting surface 30) is incident and emitted to the optical deflector 40 will be referred to as the first region 50a, and the portion different from the first region 50a where the laser beam Ray2 reflected and two-dimensionally deflected by the optical deflector 40 is incident and emitted to the outside will be referred to as the second region 50b. The first region 50a is the optical element portion within the range surrounded by the dotted line indicated by reference symbol 50a in Fig. 3. Similarly, the second region 50b is the optical element portion within the range surrounded by the dashed line indicated by reference symbol 50b in Fig. 3.

[0025] The first surface 51 includes a first optical surface 51a and a second optical surface 51b arranged below it, but the arrangement of the first optical surface 51a and the second optical surface 51b changes depending on the position and emission direction of the light source 20, and therefore does not necessarily have to be in the vertical direction.

[0026] The first optical surface 51a is an optical surface having a refractive power on the optical element entrance side of the first region 50a, and is a surface having a positive refractive power in FIG. 3. The first optical surface 51a is provided in a region of the first surface 51 where the laser beam Ray1 reflected by the reflecting surface 30 is incident. The first optical surface 51a is provided, for example, so that the laser beam Ray1 reflected by the reflecting surface 30 and transmitted through the optical element 50 (first region 50a) is incident on the optical deflector 40 (mirror section 41) with a desired spot and optical performance. The optimal light beam is incident on the optical deflector 40 (mirror section 41), thereby improving the projected image.

[0027] On the other hand, the second optical surface 51b is an optical surface having a refractive power on the optical element emission side of the second region 50b, and is a surface having a negative refractive power in FIG. 3. The second optical surface 51b is provided below the first optical surface 51a of the first surface 51, that is, in the region where the laser beam Ray2 that is reflected and two-dimensionally deflected by the optical deflector 40 and passes through the optical element 50 (second region 50b) is emitted. The second optical surface 51b has the effect of widening the emitted light beam and enlarging the projected image. In addition, by using an aspheric surface, it is also possible to perform distortion aberration and keystone correction.

[0028] As described above, according to this embodiment, by providing different optical functions to the first region 50a of the optical element 50 through which the laser beam from the light source 20 passes and the second region 50b of the optical element 50 through which the laser beam reflected and two-dimensionally deflected by the optical deflector 40 passes, it is possible to effectively suppress various aberrations, to easily obtain a high-quality projected image, and to suppress the narrowing of the angle of view caused by the optical element 50. In addition, it is possible to ensure a good projected image and a wide angle of view.

[0029] Next, a modified example will be described.

[0030] In the above embodiment, the optical element 50 is configured using one type of material, but the present invention is not limited to this. For example, the optical element 50 may be configured using two or more types of materials to reduce chromatic aberration. For example, the optical element 50 may be configured by using different materials for the prism parts 53, 51a, and 51b, and combining them via adhesive surfaces.

[0031] FIG. 4 shows a first modified example of the optical element 50. In FIG.

[0032] As shown in FIG. 4, the first optical surface 51a and the second optical surface 51b may both be optical surfaces having positive refractive power. By providing appropriate refractive power to each of them, it is possible to correct various aberrations and shape the light beam from the light source 20.

[0033] FIG. 5( a ) shows a second modified example of the optical element 50 , and FIG. 5( b ) shows a third modified example of the optical element 50 .

[0034] As shown in Fig. 5(a), the second optical surface 51b of the second region 50b may be omitted. In this case, the first optical surface 51a on the incident side of the first region 50a may be a surface having negative refractive power as shown in Fig. 5(b).

[0035] FIG. 6( a ) shows a fourth modified example of the optical element 50 , and FIG. 6( b ) shows a fifth modified example of the optical element 50 .

[0036] 6(a), a third optical surface 52a having refractive power may be provided on the optical deflector side of the first region 50a. Also, a fourth optical surface 52b having refractive power may be provided on the optical deflector side of the second region 50b. As described above, it is sufficient that the optical surface having refractive power is provided on at least one of the entrance side and exit side of the first region 50a and the entrance side and exit side of the second region 50b.

[0037] As shown in FIG. 6(b), the third optical surface 52a of the first region 50a and the fourth optical surface 52b of the second region 50b do not necessarily have a region boundary, and if possible, may have a continuous surface like optical surfaces 52a and 52b in FIG. 6(b).

[0038] In the above embodiment and each of the above modified examples, the first optical surface 51a to the fourth optical surface 52b are described as convex lens surfaces (or concave lens surfaces), but the present invention is not limited thereto. That is, the first optical surface 51a to the fourth optical surface 52b may be any optical surface having different optical actions. For example, the first optical surface 51a to the fourth optical surface 52b may be a lens surface having a positive refractive power, a lens surface having a negative refractive power, or a diffusing surface. The first optical surface 51a to the fourth optical surface 52b may be a free curved surface, a curved surface, a microlens, or a Fresnel lens. The first optical surface 51a to the fourth optical surface 52b may be a spherical lens or an aspherical lens. The different optical actions mean optical actions different from simple refraction. For example, the different optical action means, for the first optical surface 51a and the second optical surface 51b, a different optical action from the first surface 51 which is a base surface on which the first optical surface 51a and the second optical surface 51b are provided. Similarly, for the third optical surface 52a and the fourth optical surface 52b, it means, for the third optical surface 52a and the fourth optical surface 52b, a different optical action from the second surface 52 which is a base surface on which the third optical surface 52a and the fourth optical surface 52b are provided.

[0039] Fig. 7 shows a sixth modified example of the optical element 50. Fig. 8 shows a seventh modified example of the optical element 50. Fig. 9 shows an eighth modified example of the optical element 50.

[0040] As shown in Fig. 7, the exit side optical surface 51b of the second region 50b may have a shape that is elongated in one direction (see the upper part of Fig. 7), or may have a shape that is rotationally symmetric about the optical axis (see the lower part of Fig. 7). This deformation may be appropriately selected depending on the difficulty of manufacturing the optical element, and is also effective in reducing the size.

[0041] In this case, the second optical surface 51b on the exit side of the second region 50b, which is elongated in one direction, may be arranged parallel to the optical element 50 (see the upper part of Figure 7) or may be arranged at an angle to the optical element 50 (see Figure 8).

[0042] Also, as shown in FIG. 9, the second optical surface 51b on the exit side of the second region 50b and having a shape extended in one direction may be one (see the upper part of FIG. 7 and FIG. 8), or may be multiple (see FIG. 9).

[0043] 8 and 9 may be applied not only to the exit side of the second region 50b but also to any of the entrance side, exit side, and entrance side of the second region 50b. This modification makes it easier to guide the light beam regardless of the entrance and exit directions of the light beam. In the above embodiment, the light source 20 is a light source module that emits a single laser beam Ray1 obtained by combining (combining) laser beams of three primary colors (RGB), but the present invention is not limited to this. For example, the light source 20 may be a light source module that emits a single color laser beam.

[0044] In the above embodiment, the optical element of the present disclosure and the projection device using the same are applied to a laser scanning projector (or a picoprojector), but the present disclosure is not limited thereto. For example, the optical element of the present disclosure and the projection device using the same may be applied to smart glasses, a micro projector, an interactive projector, or a lidar.

[0045] The numerical values ​​shown in the above embodiments are all examples, and it goes without saying that suitable numerical values ​​different from these can be used.

[0046] The above-described embodiments are merely examples in all respects. The present disclosure should not be construed as being limited by the description of the above-described embodiments. The present disclosure can be implemented in various other forms without departing from the spirit or main characteristics thereof. [Explanation of symbols]

[0047] 10...Projection device 20...Light source 30…Reflective surface 40...Light deflector 41…Mirror section 50a…First Area 50b…Second Region 51...Side 1 51a...first optical surface 51b…Second optical surface 52a…Third optical surface 52b...Fourth optical surface 52…Second side 53...transparent body 60...Control device 70…Housing 71...Light exit L1…distance Ray1, Ray2...Laser beam S…Screen

Claims

1. An optical element disposed between a light source and an optical deflector that reflects and two-dimensionally deflects incident light, a first region for receiving light from the light source and outputting the light to the optical deflector; a second region different from the first region into which the light reflected and two-dimensionally deflected by the optical deflector is incident and emitted to the outside; An optical element in which optical surfaces having different optical functions are provided on at least one of the entrance side and exit side of the first region and the entrance side and exit side of the second region.

2. The optical element according to claim 1 , wherein the optical surface has a refractive power.

3. The optical element according to claim 1 , further comprising an optical surface having a refractive power provided on the exit side of at least the second region.

4. The optical element according to claim 1 , further comprising an optical surface having a refractive power provided on the incident side of at least the first region.

5. The optical element according to claim 1 , wherein at least the optical effects of the incident side of the first region and the exit side of the second region are different from each other.

6. The optical element according to claim 1 , wherein the optical element is made of at least two kinds of materials.

7. A light source; an optical deflector that reflects and two-dimensionally deflects incident light; A projection device comprising the optical element according to claim 1 .

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