CN211086892U

CN211086892U - Ventilation plate, ventilation grid and projection equipment

Info

Publication number: CN211086892U
Application number: CN201922137872.3U
Authority: CN
Inventors: 刘宪; 邓高飞; 余新; 李屹
Original assignee: Appotronics Corp Ltd
Current assignee: Shenzhen Appotronics Corp Ltd
Priority date: 2019-12-03
Filing date: 2019-12-03
Publication date: 2020-07-24
Anticipated expiration: 2029-12-03
Also published as: WO2021109780A1

Abstract

The application provides a ventilating board, ventilation bars and projection equipment, projection equipment is arranged in to the ventilation bars, the ventilation bars includes the framework, a plurality of first shielding piece and a plurality of second shielding piece, a plurality of ventilation holes have been seted up to the framework, every first shielding piece is connected with the framework and extends to one side of framework, every first shielding piece shelters from a ventilation hole, every second shielding piece is connected with the framework and extends to the opposite side of framework, every second shielding piece shelters from a ventilation hole. The application provides a ventilation grid and projection equipment solve the heat dissipation problem through seting up the ventilation hole in the framework to set up first shielding piece and second shielding piece in the framework, make each ventilation hole shelter from by a first shielding piece and a second shielding piece, can prevent effectively that external hard thing from directly passing inside the ventilation hole gets into projection equipment, thereby guaranteed that heat dissipation and protection level all meet the requirements.

Description

Ventilation plate, ventilation grid and projection equipment

Technical Field

The application relates to the technical field of projection, in particular to a ventilation plate, a ventilation grid and projection equipment.

Background

The projection device is usually provided with a heat dissipation hole to dissipate the internal heat to the external environment, and if the heat dissipation hole is not designed reasonably, the projection device may have good heat dissipation but a PROTECTION level (INGRESS PROTECTION RATING) that does not meet the requirement, or the projection device may have a PROTECTION level that meets the requirement but has poor heat dissipation.

SUMMERY OF THE UTILITY MODEL

The embodiment of the application provides a ventilation board, a ventilation grid and projection equipment, so as to solve the technical problem.

The embodiment of the application realizes the aim through the following technical scheme.

In a first aspect, the embodiment of the application provides a ventilation board, the ventilation board sets up in projection equipment, the ventilation board includes plate body and at least one ventilation hole structure, the plate body includes outside lateral wall of orientation and the inside wall of orientation projection equipment, the ventilation hole structure forms in the plate body, the ventilation hole structure is including forming at the lateral wall and along the outside first shielding piece that extends of lateral wall and forming at the medial wall and along the inside wall to the inside second shielding piece that extends of projection equipment, first shielding piece encloses into first ventilation runner, the second shielding piece encloses into the second ventilation runner that is linked together with first ventilation runner, first shielding piece and second shielding piece mutually support and form sight shielding structure, in order to prevent that the observer from snooping projection equipment's inside through ventilation hole structure.

In some embodiments, the first and second blinders are symmetrically disposed about the plate body.

In some embodiments, the first and second blinders are offset with respect to the plate body.

In some embodiments, the vent structure includes a side wall enclosing the vent, the first shield shields the side wall along an orthographic projection of the outer side wall in a direction toward the inner side wall, and the second shield shields the side wall along an orthographic projection of the inner side wall in a direction toward the outer side wall.

In a second aspect, the embodiment of the application provides a ventilation grid, the ventilation grid is adapted to projection equipment, the ventilation grid comprises a frame body, a plurality of first shielding pieces and a plurality of second shielding pieces, a plurality of vent holes are formed in the frame body, each first shielding piece is connected with the frame body and extends towards one side of the frame body, each first shielding piece shields one vent hole, each second shielding piece is connected with the frame body and extends towards the other side of the frame body, and each second shielding piece shields one vent hole.

In some embodiments, the first and second blinders are symmetrically disposed about the frame.

In some embodiments, the first shield includes first and second opposing edges, the first edge being connected to the frame and the second edge being spaced apart from the frame, the second shield includes third and fourth opposing edges, the third edge being connected to the frame and the fourth edge being spaced apart from the frame.

In some embodiments, the frame body comprises an outer side wall and an inner side wall which are opposite to each other, the ventilation hole penetrates through the outer side wall and forms a first opening, the ventilation hole penetrates through the inner side wall and forms a second opening, and the first opening and the second opening are opposite to each other or are staggered.

In some embodiments, an orthographic projection of the first shield obscures the first opening in a direction from the outer sidewall to the inner sidewall; the second opening is shielded by the orthographic projection of the second shielding piece along the direction of the inner side wall towards the outer side wall.

In a third aspect, an embodiment of the present application provides a projection apparatus, where the projection apparatus includes the ventilation board of any of the above embodiments or the ventilation grid of any of the above embodiments.

The application provides a ventilating board, ventilation grid and projection equipment solve the heat dissipation problem through seting up the ventilation hole in the framework to set up first shielding piece and second shielding piece in the framework, make each ventilation hole shelter from by a first shielding piece and a second shielding piece, can prevent effectively that external hard thing from directly passing inside the ventilation hole gets into projection equipment, thereby guaranteed that heat dissipation and protection level all accord with the requirement.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic structural view (view of outer side wall) of a ventilation grid provided in an embodiment of the present application.

Fig. 2 is a schematic structural view of an inner sidewall view of the ventilation grid of fig. 1.

Fig. 3 is a schematic view of the outside wall of the ventilation grid of fig. 1.

Fig. 4 is a schematic cross-sectional view of the ventilation grid of fig. 3 taken along line IV-IV.

Fig. 5 is another schematic cross-sectional view of the ventilation grid of fig. 3.

Fig. 6 is a schematic cross-sectional view of a ventilation grid according to another embodiment of the present application.

Fig. 7 is a schematic cross-sectional view of a ventilation grid according to yet another embodiment of the present application.

Fig. 8 is a schematic structural view (outer side wall view) of a ventilation board provided in an embodiment of the present application.

Fig. 9 is a schematic cross-sectional view of a ventilation board according to another embodiment of the present application.

Fig. 10 is a schematic cross-sectional view of a ventilation board according to yet another embodiment of the present application.

Fig. 11 is a schematic cross-sectional view of a ventilation board according to yet another embodiment of the present application.

Fig. 12 is a schematic structural diagram of a projection apparatus according to an embodiment of the present application.

Detailed Description

In order to make the technical solutions better understood by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. It is to be understood that the embodiments described are only a few embodiments of the present application and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application.

Referring to fig. 1 and 2, an embodiment of the present application provides a ventilation grid 100, the ventilation grid 100 is disposed in a projection apparatus, the ventilation grid 100 includes a frame 10, a plurality of first shielding members 20 and a plurality of second shielding members 30, referring to fig. 3 and 4, the frame 10 is provided with a plurality of ventilation holes 11, each first shielding member 20 is connected to the frame 10 and extends toward one side of the frame 10, each first shielding member 20 shields one ventilation hole 11, each second shielding member 30 is connected to the frame 10 and extends toward the other side of the frame 10, and each second shielding member 30 shields one ventilation hole 11.

The ventilation grill 100 may have a circular plate shape, an elliptical plate shape, a prismatic plate shape, or the like, and in the present embodiment, the ventilation grill 100 has a substantially rectangular plate shape. The ventilation grid 100 can be used as a heat dissipation structure of projection equipment such as cinema projectors, engineering projectors, micro projectors, education projectors, wall splicing projectors and laser televisions, and the ventilation grid 100 can be detachably mounted on a shell of the projection equipment so as to facilitate detection, maintenance and dust cleaning of users. In other embodiments, the ventilation grid 100 may be integrated with the housing of the projection device.

The frame 10 may have a circular plate shape, an elliptical plate shape, a prismatic plate shape, or the like, and in the present embodiment, the frame 10 has a rectangular plate shape.

The first and

second shields

20, 30 may each be sheet-like. The number of the first and

second shields

20, 30 corresponds to the number of the vent holes 11, and in the present embodiment, the number of the first shields 20 is eight, and the number of the second shields 30 is eight. The first and

second shields

20 and 30 extend from the surface of the frame 10 to both sides and protrude from the frame 10, and one first shield 20 and one second shield 30 shield the same vent hole 11. Any one of the first shielding piece 20 and the second shielding piece 30 can be located inside the projection device, and correspondingly, the other one of the first shielding piece 20 and the second shielding piece 30 is located outside the projection device, so that even if an external hard object passes through the vent hole 11 by bypassing one shielding piece, the external hard object can enter the projection device by bypassing the other shielding piece, and the difficulty of the external hard object entering the projection device is increased.

The description of the present application with respect to the first and

second shields

20 and 30 shielding the vent hole 11 does not mean that the first or second shield 30 closes the vent hole 11, but means that the path of the external hard object passing through the vent hole 11 from one side to the other side of the frame is bent due to the shielding of the first and

second shields

20 and 20, and the external hard object cannot pass through the vent hole 11 directly due to the first or

second shield

20 or 30

The second shield 30 does not close the vent hole 11 and thus does not affect the heat dissipation of the projection device.

Referring to fig. 4 and 5, the frame 10 includes an outer sidewall 12 and an inner sidewall 13 opposite to each other. The vent hole 11 penetrates the outer side wall 12 and forms a first opening 120 in the frame 10, and the vent hole 11 penetrates the inner side wall 13 and forms a second opening 130 in the frame 10. The vent hole 11 is a collection of the first opening 120 and the second opening 130. The vent holes 11 may be circular, oval, triangular, quadrangular, etc., and in the present embodiment, the vent holes 11 are rectangular. The number of the vent holes 11 is plural, for example, the number of the vent holes 11 may be four or eight or sixteen, etc., and in this embodiment, the number of the vent holes 11 is eight. The plurality of ventilation holes 11 are distributed in the frame body 10 at intervals, and the plurality of ventilation holes 11 may be irregularly arranged or regularly arranged. For example, the plurality of vent holes 11 may be arranged at equal intervals to form a column, may be arranged at equal intervals to form a row, or may be arranged at the same time to form a plurality of columns and a plurality of rows. In the present embodiment, the plurality of vent holes 11 are regularly arranged to form four rows and two columns, as shown in fig. 3. When the frame 10 is molded by a mold, the regular arrangement of the plurality of vent holes 11 is advantageous for simplifying the difficulty in designing the mold, and the difficulty in manufacturing the frame 10 can be reduced.

The present application describes with respect to the terms "row", "column", etc., the positional relationship between the structures in fig. 3 is taken as a reference.

The application provides a ventilation grid 100 solves the heat dissipation problem through seting up ventilation hole 11 at framework 10 to set up first shielding piece 20 and second shielding piece 30 in framework 10, make each ventilation hole 11 shelter from by a first shielding piece 20 and a second shielding piece 30, can prevent effectively that external hard thing from directly passing ventilation hole 11 and getting into inside the projection equipment, thereby guaranteed that heat dissipation and protection level all meet the requirements.

Referring to fig. 3, the first shielding member 20 includes a first edge 21 and a second edge 22 opposite to each other, the first edge 21 is connected to the frame 10, and the first edge 21 may be linear, curved, or zigzag, and in this embodiment, the first edge 21 is linear. The second edge 22 is spaced from the frame 10, and the shape of the second edge 22 is similar to the shape of the first edge 21. Referring to fig. 2, the second shielding member 30 includes a third edge 31 and a fourth edge 32 opposite to each other, the third edge 31 is connected to the frame 10, and the shape of the third edge 31 is the same as that of the first edge 21. The fourth edge 32 is spaced from the frame 10, and the shape of the fourth edge 32 is the same as the shape of the second edge 22.

In the embodiment, the first shielding member 20 is located outside the projection apparatus, and the second shielding member 30 is located inside the projection apparatus as an example, since the first edge 21 is connected to the frame 10, and the second edge 22 is closer to the bottom of the projection apparatus than the first edge 21, when a foreign object such as an external hard object or a falling liquid falls on the surface of the first shielding member 20 in a normal use posture of the projection apparatus, the foreign object cannot slide into the ventilation hole 11 along the first shielding member 20. Similarly, the third edge 31 is connected to the frame 10, and the fourth edge 32 is closer to the bottom of the projection device than the third edge 31, so that external hard objects can be better prevented from directly passing through the ventilation holes 11.

Referring to fig. 3, the first shielding member 20 further includes a first curved surface portion 23 and a second curved surface portion 24 opposite to each other, the first curved surface portion 23 and the second curved surface portion 24 are both connected to the frame body 10, the first curved surface portion 23 and the second curved surface portion 24 are respectively connected to the first edge 21, and the first curved surface portion 23 and the second curved surface portion 24 may be both linear. Referring to fig. 2, the second shielding member 30 further includes a third curved surface portion 33 and a fourth curved surface portion 34 opposite to each other, the third curved surface portion 33 and the fourth curved surface portion 34 are both connected to the frame body 10, and the third curved surface portion 33 and the fourth curved surface portion 34 are respectively connected to the third edge 31. The first shielding piece 20 is connected with the frame body 10 through the first edge 21, the first curved surface portion 23 and the second curved surface portion 24 respectively, and the second shielding piece 30 is connected with the frame body 10 through the third edge 31, the third curved surface portion 33 and the fourth curved surface portion 34 respectively, so that the first shielding piece 20 and the second shielding piece 30 can better surround the vent hole 11, and the difficulty of external hard objects entering the projection equipment can be increased under the condition that a good heat dissipation effect is ensured.

The first and

second shields

20, 30 are disposed symmetrically with respect to the frame body 10. For example, as shown in FIG. 4, the first opening 120 is aligned with the second opening 130, and the central axis of the vent hole 11 is perpendicular to the outer sidewall 12 and the inner sidewall 13. In other embodiments, the first and

second shutters

20 and 30 may be disposed asymmetrically with respect to the frame 10. For example, as shown in fig. 6, the first opening 120 is offset from the second opening 130, and the centers of the first opening 120 and the second opening 130 are not opposite to each other.

The orthographic projection of the first shutter 20 on the outer side wall 12 blocks the first opening 120. As shown in fig. 4 and 6, the boundary of the orthographic projection of the first shielding member 20 coincides with the edge of the orthographic projection of the first opening 120, which helps to enhance the heat dissipation effect of the ventilation grid 100 and also ensures the shielding effect of the ventilation grid 100. In other embodiments, as shown in fig. 7, the boundary of the orthographic projection of the first shield 20 exceeds the edge of the orthographic projection of the first opening 120, which helps to enhance the shielding effect of the ventilation board 100.

Similarly, the orthographic projection of the second shutter 30 on the inner side wall 13 occludes the second opening 130.

The first shielding member 20 and the second shielding member 30 of the present embodiment cooperate with each other and jointly shield the first opening 120 and the second opening 130 of the ventilation hole 11, so that when a user views the projection apparatus at any angle, parts such as optical elements, circuit boards, cables, and the like inside the projection apparatus cannot be directly seen by the user, and the shielding effect is effectively enhanced.

Referring to fig. 8 and 9, an embodiment of the present application further provides a ventilation board 100, where the ventilation board 100 is disposed in the projection apparatus, and the ventilation board 100 has a peep-proof function, so that an observer located around the projection apparatus cannot peep into the projection apparatus through the ventilation board 100, and the ventilation board 100 helps heat generated inside the projection apparatus to be dissipated to the outside of the projection apparatus, thereby improving a heat dissipation effect of the projection apparatus.

The ventilation board 100 comprises a board body 10 and at least one ventilation hole structure 40, wherein the board body 10 comprises an outer side wall 12 and an inner side wall 13, the outer side wall 12 faces the outside, and the inner side wall 13 faces the inside of the projection device.

The number of the vent structures 40 may be one or two or three, etc., and in the present embodiment, the number of the vent structures 40 is eight. The vent structure 40 is formed on the plate body 10, and the vent structure 40 includes first shielding piece 41, second shielding piece 42 and runs through the through-hole of plate body 10, first shielding piece 41 is formed at lateral wall 12 and outwards extends along lateral wall 12, second shielding piece 42 is formed at inside wall 13 and extends to projection equipment inside along lateral wall 13, first shielding piece 41 encloses into first ventilation runner 410, second shielding piece 42 encloses into second ventilation runner 420, second ventilation runner 420 is linked together with first ventilation runner 410, outside cold wind gets into projection equipment inside through first ventilation runner 410 and second ventilation runner 420 in proper order for projection equipment dispels the heat. The first shielding piece 41 and the second shielding piece 42 are matched with each other to form a sight shielding structure, so that an observer is prevented from snooping the inside of the projection device through the vent hole structure, when the observer watches the projection device at any angle, parts such as optical elements, circuit boards and cables in the projection device cannot be directly seen by the observer, and the shielding effect is effectively enhanced.

The ventilation board 100 that this application provided solves the heat dissipation problem through forming ventilation hole structure 40 at framework 10 to mutually support first shielding piece 41 and second shielding piece 42 and form sight shielding structure, can prevent effectively that external observer from snooping projection equipment's inside through ventilation hole structure, thereby guaranteed that heat dissipation and protection level all meet the requirements.

In some embodiments, the first and

second blinders

41 and 42 are symmetrically disposed about the plate body 10. For example, the first shielding member 41 and the second shielding member 42 are opposite to each other, which facilitates smooth path of the wind through the first ventilation flow channel 410 and the second ventilation flow channel 420, and simultaneously ensures shielding effect of the ventilation board 100. In other embodiments, the first shielding member 41 and the second shielding member 42 may also be disposed asymmetrically with respect to the frame 10, for example, as shown in fig. 5, the first shielding member 41 and the second shielding member 42 are disposed in a staggered manner with respect to the plate body 10, which is helpful for enhancing the shielding effect of the ventilation board 100 and improving the heat dissipation effect of the ventilation board 100.

In some embodiments, as shown in fig. 9, vent structure 40 includes a side wall 43 that encloses the vent, a first shield 41 shields side wall 43 along an orthographic projection of outer side wall 12 in a direction toward inner side wall 13, and a second shield 42 shields side wall 43 along an orthographic projection of inner side wall 13 in a direction toward outer side wall 12. As shown in fig. 9 and 10, the boundary of the orthographic projection of the first shielding member 41 and the second shielding member 42 coincides with the edge of the orthographic projection of the side wall 43, which helps to enhance the heat dissipation effect of the ventilation board 100 and also ensures the shielding effect of the ventilation board 100. In other embodiments, as shown in fig. 11, the boundary of the orthographic projection of the first and

second blinders

41 and 42 exceeds the edge of the orthographic projection of the side wall 43, which helps to enhance the blinding effect of the ventilation board 100.

Referring to fig. 12, an embodiment of the present disclosure further provides a projection device 200, where the projection device 200 may be a cinema projector, an engineering projector, a mini projector, an educational projector, a wall splicing projector, a laser television, and so on.

In some embodiments, the projection device 200 includes the ventilation grid 100 of any of the embodiments described above. The application provides a projection apparatus 200 solves the heat dissipation problem by seting up ventilation hole 11 at framework 10, and set up first shielding piece 20 and second shielding piece 30 in framework 10, make each louvre shelter from by a first shielding piece 20 and a second shielding piece 30, can prevent effectively that external hard thing from directly passing ventilation hole 11 and getting into projection apparatus 200 inside, thereby guaranteed that heat dissipation and protection level all meet the requirements.

In other embodiments, the projection apparatus 200 includes the ventilation board 100 according to any of the above embodiments, the projection apparatus 200 provided by the present application solves the problem of heat dissipation by forming the ventilation hole structure 40 in the frame 10, and the first shielding member 41 and the second shielding member 42 cooperate with each other to form a line-of-sight shielding structure, so that an external observer can be effectively prevented from peeping into the projection apparatus through the ventilation hole structure, thereby ensuring that both the heat dissipation and the protection level meet the requirements.

The projection device 200 further includes a housing 201, the ventilation grid 100 is located on a side wall of the housing 201, and the ventilation grid 100 may be integrated with the housing 201 as a whole, for example, the ventilation grid 100 and the housing 201 are molded by a mold; or the ventilation grid 100 and the shell 201 are taken as two independent parts, the shell 201 is provided with a mounting hole, the ventilation grid 100 is mounted in the mounting hole, and the ventilation grid 100 and the shell 201 can form an integral structure in a gluing mode.

In other embodiments, the ventilation grid 100 and the housing 201 are provided as two separate parts, which are detachably connected, for example, the ventilation grid 100 and the housing 201 can be connected by a screw thread, a snap fit, etc. The removable attachment of the ventilation grid 100 to the housing 201 facilitates the ability of a user to remove the ventilation grid 100 from the housing 201 for maintenance and cleaning.

The number of the ventilation grills 100 can be one or more than one, and a plurality of the ventilation grills 100 can be arranged at intervals or can be arranged closely.

In the above embodiment, the ventilation board 100 may be combined with the housing 201 instead of the ventilation grid 100 to perform the same function as the ventilation grid 100. For example, the ventilation board 100 and the housing 201 are formed as a single structure, or the ventilation board 100 and the housing 201 are detachably connected, as described in the above embodiment.

In this application, the terms "mounted," "connected," "secured," and the like are to be construed broadly unless otherwise specifically stated or limited. For example, the connection can be fixed, detachable or integrated; can be mechanically or electrically connected; they may be directly connected or indirectly connected through an intermediate member, or they may be connected through the inside of two elements, or they may be connected only through surface contact or through surface contact of an intermediate member. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

Furthermore, the terms "first," "second," and the like are used merely for distinguishing between descriptions and not intended to imply or imply a particular structure. The description of the terms "some embodiments," "other embodiments," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiments or examples is included in at least one embodiment or example of the invention. In this application, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this application can be combined and combined by those skilled in the art without contradiction.

The above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present application and are intended to be included within the scope of the present application.

Claims

1. The utility model provides a ventilation board with peep-proof function, the ventilation board sets up in projection equipment, its characterized in that, the ventilation board includes:

a plate body including an outer sidewall facing the outside and an inner sidewall facing the inside of the projection apparatus; and

at least one vent structure formed on the board body, wherein the vent structure comprises a first shielding piece formed on the outer side wall and extending outwards along the outer side wall, and a second shielding piece formed on the inner side wall and extending inwards the projection device along the inner side wall; the first shielding piece surrounds a first ventilation flow channel, the second shielding piece surrounds a second ventilation flow channel communicated with the first ventilation flow channel, and the first shielding piece and the second shielding piece are matched with each other to form a sight shielding structure so as to prevent an observer from peeping the inside of the projection equipment through the ventilation hole structure.

2. A ventilation board as claimed in claim 1, wherein the first and second blinders are symmetrically disposed about the board body.

3. A ventilation board as claimed in claim 1, wherein the first and second blinders are offset with respect to the board body.

4. A ventilation board as claimed in claim 1, wherein the ventilation hole structure includes a side wall enclosing a ventilation hole, the first shield member shields the side wall along an orthographic projection of the outer side wall in a direction of the inner side wall, and the second shield member shields the side wall along an orthographic projection of the inner side wall in a direction of the outer side wall.

5. A ventilation grid for placement in a projection device, the ventilation grid comprising:

the frame body is provided with a plurality of vent holes;

each first shielding piece is connected with the frame body and extends towards one side of the frame body, and each first shielding piece shields one vent hole; and

each second shielding piece is connected with the frame body and extends towards the other side of the frame body, and each second shielding piece shields one vent hole.

6. A ventilation grid according to claim 5, wherein the first and second screen members are symmetrically disposed about the frame.

7. A ventilation grid according to claim 5, wherein the first screen comprises first and second opposed edges, the first edge being connected to the frame and the second edge being spaced from the frame;

the second shielding piece comprises a third edge and a fourth edge which are opposite to each other, the third edge is connected with the frame body, and the fourth edge is spaced from the frame body.

8. The ventilation grid according to claim 5, wherein the frame body comprises opposing outer and inner side walls, the ventilation holes extending through the outer side wall and forming a first opening, the ventilation holes extending through the inner side wall and forming a second opening, the first opening being aligned with or offset from the second opening.

9. The ventilation grid according to claim 8, wherein an orthographic projection of the first shield obscures the first opening in a direction from the outer sidewall toward the inner sidewall;

and the orthographic projection of the second shielding piece shields the second opening along the direction from the inner side wall to the outer side wall.

10. A projection device comprising a ventilation board as claimed in any one of claims 1 to 4 or a ventilation grid as claimed in any one of claims 5 to 9.