Electrical circuit module and projection display device

Abstract

To prevent dust from entering the interior of a case housing a circuit board within an electrical circuit module.SOLUTION: An electrical circuit module comprises a circuit board unit 2 and a case 3 for housing the circuit board unit. The case comprises a case body 31 having an opening in a predetermined direction and a housing space S for accommodating the circuit board unit, a cover body covering the opening 31A of the case body, and a side member 33 attached to the inner surface of the case body. The case body comprises a flat-viewed polygonal base plate section and a plurality of side plate sections 36 that extend from each edge of the base plate section toward one side in the thickness direction of the base plate section by being folded from each edge of the base plate section, thereby forming an opening of the case body. The side member is arranged to overlap at least the inner surfaces of adjacent side plate sections, thereby covering the gap G1 between the adjacent side plate sections.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an electric circuit module and a projection display device. [Background technology]

[0002] Patent Document 1 discloses an electric circuit module (control circuit module) in which a circuit board unit (control circuit board) having various electric components mounted on a circuit board is sealed in insulating resin. In the electric circuit module of Patent Document 1, the insulating resin protects the circuit board unit from dust, corrosive gases, etc. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-121861 Summary of the Invention [Problem to be solved by the invention]

[0004] In some electric circuit modules, the circuit board unit is housed in a case without being sealed with resin. However, simply housing the circuit board unit in the case without any special measures may allow dust to get inside through gaps in the case.

[0005] This invention has been made in consideration of the above-mentioned circumstances, and aims to provide an electrical circuit module that can prevent dust from entering the inside of a case that houses a circuit board unit, and a projection display device that includes the same. [Means for solving the problem]

[0006] One aspect of the present invention is an electric circuit module including a circuit board unit and a case that houses the circuit board unit. The case includes a case body that opens in a predetermined direction and has an accommodation space for accommodating the circuit board unit, a lid that covers the opening of the case body, and side members attached to the inner surface of the case body. The case body has a bottom plate portion that is polygonal in plan view, and a plurality of side plate portions that are bent about each edge of the bottom plate portion to extend from each edge of the bottom plate portion to one side in the thickness direction of the bottom plate portion and form an opening in the case body. The side plate members are arranged to overlap the inner surfaces of at least adjacent side plate portions, thereby covering the gap between adjacent side plate portions.

[0007] Another aspect of the present invention is a projection display device including the electric circuit module. [Effects of the Invention]

[0008] According to the present invention, in an electric circuit module, it is possible to prevent dust from entering the inside of a case that houses a circuit board. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view showing the appearance of an electric circuit module according to an embodiment of the present invention; [Figure 2] FIG. 2 is a cross-sectional view of the electric circuit module of FIG. [Figure 3] 2 is a perspective view showing a state in which a cover is removed from the electric circuit module of FIG. 1. FIG. [Figure 4] FIG. 4 is a plan view of the structure of FIG. 3 as seen from above. [Figure 5] FIG. 3 is an exploded perspective view of a case that constitutes the electric circuit module of FIGS. 1 and 2. [Figure 6] FIG. 4 is an enlarged perspective view of an area VI in FIG. 3. [Figure 7] FIG. 7 is an enlarged plan view of region VII in FIG. 4. [Figure 8]3 is a perspective view illustrating a manner in which the cover is attached to the case body by screws in the electric circuit module of FIG. 1 and FIG. 2. FIG. [Figure 9] FIG. 9 is a perspective view illustrating the manner in which the lid is attached, following FIG. 8. [Figure 10] FIG. 10 is a perspective view illustrating the manner in which the lid is attached, following FIG. 9. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described with reference to Figures 1 to 10. In the following description, expressions indicating relative or absolute arrangements, such as "parallel," "orthogonal," and "center," not only strictly indicate such arrangements, but also indicate a state in which there is a relative displacement with a tolerance or an angle or distance to the extent that the same function is obtained.

[0011] In the drawings of this embodiment, the direction indicated by the symbol Z corresponds to the height direction or thickness direction of the electric circuit module described below. In the following description, this will sometimes be referred to as the Z direction. The side toward which the Z direction arrow points (+Z side) will sometimes be referred to as the "upper side." The side opposite to the side toward which the Z direction arrow points (-Z side) will sometimes be referred to as the "lower side." Note that the terms "upper side" and "lower side" are simply names used to describe the relative positional relationships of the various parts, and the actual positional relationships may be other than those indicated by these names.

[0012] The direction indicated by the symbol X is a linear direction perpendicular to the Z direction, and corresponds to the width direction (or lateral direction) of the electric circuit module. In the following explanation, this will be referred to as the X direction. The side toward which the X direction arrow points (+X side) will be referred to as "one side of the X direction," and the side opposite to the side toward which the X direction arrow points (-X side) will be referred to as "the other side of the X direction."

[0013] The direction indicated by the symbol Y is a linear direction perpendicular to the Z and X directions, and corresponds to the depth direction (or vertical direction) of the electric circuit module. In the following explanation, this will be referred to as the Y direction. The side toward which the Y direction arrow points (+Y side) will be referred to as "one side of the Y direction," and the side opposite to the side toward which the Y direction arrow points (-Y side) will be referred to as "the other side of the Y direction."

[0014] As shown in FIGS. 1 and 2, the electric circuit module 1 according to this embodiment includes a circuit board unit 2 and a case 3 that houses the circuit board unit 2.

[0015] As shown in Figures 2 to 4, the circuit board unit 2 includes a circuit board 21, an external connection terminal 22 mounted on the circuit board 21, and a plurality of electrical components 23 mounted on the circuit board 21 to form the electrical circuit of the circuit board unit 2. The circuit board 21 may have any shape in plan view. In this embodiment, the circuit board 21 is formed in a rectangular shape in plan view with its short sides in the X direction and its long sides in the Y direction.

[0016] The external connection terminals 22 are terminals for electrically connecting the electrical circuit of the circuit board unit 2 to other components or units. Cables extending to other components or units are connected to the external connection terminals 22. The external connection terminals 22 may be, for example, input terminals for inputting power or signals to the circuit board unit 2, or output terminals for outputting power or signals from the circuit board unit 2 to other components or units.

[0017] In this embodiment, the external connection terminal 22 is mounted on a first surface 21a of the circuit board 21 facing upward. A plurality of external connection terminals 22 are mounted on the circuit board 21. The plurality of external connection terminals 22 include a first connection terminal 22A arranged at a first end of the circuit board 21, which is rectangular in plan view and located on one side in the X direction (+X side), and two second connection terminals 22B arranged at a second end of the circuit board 21 located on the opposite side in the X direction from the first end (-X side). In the illustrated example, there is one first connection terminal 22A and two second connection terminals 22B. The two second connection terminals 22B are arranged at an interval in the Y direction.

[0018] 2, the electric components 23 include first electric components 23A mounted on the first surface 21a of the circuit board 21 and second electric components 23B mounted on the second surface 21b facing downward of the circuit board 21. Some of the first electric components 23A and second electric components 23B are heat-generating components 24 that generate heat when energized.

[0019] As shown in FIGS. 1, 2, and 5, the case 3 has a case body 31, a cover 32, and side members 33.

[0020] 2 and 5, the case body 31 is formed in a box shape that opens upward (+Z direction; a predetermined direction). The case body 31 has an accommodation space S in which the circuit board unit 2 is accommodated. The case body 31 is made of a bendable plate material. The plate material that makes up the case body 31 may be conductive, such as a metal, or electrically insulating, such as a general resin.

[0021] The case body 31 has a bottom plate portion 35 and a plurality of side plate portions 36 . The bottom plate portion 35 is formed in a plate shape with the Z direction as the thickness direction. The bottom plate portion 35 may be formed in at least a polygonal shape in a plan view. The bottom plate portion 35 of this embodiment is formed in a rectangular shape in a plan view that corresponds to the shape of the circuit board 21 in a plan view. Furthermore, the size of the bottom plate portion 35 in a plan view corresponds to the size of the circuit board 21.

[0022] 5, a plurality of support bosses 351 that support the circuit board 21 are provided on the upper surface of the bottom plate portion 35 (the bottom surface of the case body 31) facing upward. The plurality of support bosses 351 support the circuit board 21 from below so that the circuit board 21 is positioned above the bottom plate portion 35 at intervals. The plurality of support bosses 351 also have female threads 352, and the circuit board 21 can be fixed to the upper ends of the plurality of support bosses 351 by screwing. In this embodiment, the support bosses 351 are arranged at the four corners of the bottom plate portion 35 that is rectangular in plan view, but the present invention is not limited to this.

[0023] The side plates 36 are bent relative to the sides of the bottom plate 35, and extend upward (in the +Z direction; one side in the thickness direction) from the sides of the bottom plate 35 to form the opening 31A of the case body 31. As a result, a gap G1 is formed between adjacent side plates 36. In this embodiment, the bottom plate portion 35 is formed in a rectangular shape in a plan view, and therefore the number of side plate portions 36 is four. The four side plate portions 36 include two first side plate portions 36A and two second side plate portions 36B. The two first side plate portions 36A are positioned at an interval in the X direction and each extend in the Y direction. The two second side plate portions 36B are positioned at an interval in the Y direction and each extend in the X direction.

[0024] Each of the two second side plate portions 36B has a bent piece 361 and a through hole 362. The bent piece 361 is formed by bending a portion of the second side plate 36B surrounded by the cutting line 363 toward the outside of the case body 31 with respect to the other portions of the second side plate 36B. In the illustrated example, the cutting line 363 formed on the second side plate 36B is formed in a U-shape that is convex upward. The portion of the second side plate 36B surrounded by the cutting line 363 is then bent downward (toward the -Z side) with respect to the other portions of the second side plate 36B, thereby forming the bent piece 361.

[0025] Two of these bent pieces 361 are formed side by side in the X direction on each second side plate portion 36B. In this embodiment, the four bent pieces 361 function as plate material portions for fixing the case 3 to another component. For example, by placing these bent pieces 361 on another component and then passing screws through the bent pieces 361, the case 3 can be fixed to the other component by screwing. The number and positions of the bent pieces 361 are not limited to those shown in the figure. The bent pieces 361 may be formed on the first side plate portion 36A, for example. The through holes 362 are formed by penetrating the second side plate portion 36B in its thickness direction in association with the formation of the above-described bent pieces 361. The number and positions of the through holes 362 correspond to the number and positions of the bent pieces 361.

[0026] 2 and 5, the lid 32 covers the opening 31A of the case body 31. The lid 32 of this embodiment has a top wall portion 37 and a peripheral wall portion . The top wall portion 37 is formed in a flat plate shape with its thickness direction in the Z direction, and covers the opening 31A of the case body 31. When covering the opening 31A of the case body 31, the top wall portion 37 comes into contact with the upper ends of the above-mentioned multiple side plate portions 36. The shape and size of the top wall portion 37 in a plan view may correspond to the shape and size of the case body 31 (bottom plate portion 35) in a plan view. The top wall portion 37 of this embodiment is formed in a rectangular shape in a plan view with a size corresponding to the bottom plate portion 35 of the case body 31.

[0027] 2, the peripheral wall portion 38 extends from the peripheral edge of the top wall portion 37 to the lower side (-Z side; one side in the thickness direction) of the top wall portion 37. The peripheral wall portion 38 overlaps the outer surfaces of all of the side plate portions 36 when the top wall portion 37 covers the opening 31A of the case body 31. In the illustrated example, the length of the peripheral wall portion 38 in the Z direction is smaller than the length of the side plate portions 36 in the Z direction, but it may be equal to the length of the side plate portions 36 in the Z direction, for example.

[0028] As shown in Figure 5, the lid 32 of this embodiment is made of a bendable plate material. Therefore, the peripheral wall 38 is bent relative to each side of the top wall 37, thereby comprising a plurality of side wall portions 38A, 38B extending downward from each side of the top wall 37. Therefore, a gap G2 (see Figure 5 in particular) is formed between adjacent side wall portions 38A, 38B. When the lid 32 covers the opening 31A of the case body 31, the gap G2 in the lid 32 overlaps with the gap G1 between adjacent side plate portions 36 of the case body 31 described above.

[0029] The plate material that forms the lid 32 may be conductive, such as a metal, or may be electrically insulating, such as a general resin.

[0030] The lid 32 is fixed to the case body 31 by screws while covering the opening 31A of the case body 31. This allows the top wall 37 of the lid 32 to be pressed against the upper ends of the side plate portions 36 of the case body 31, thereby suppressing or preventing gaps from being formed between the top wall portion 37 and the upper ends of the side plate portions 36. The lid 32 may be directly screwed to the bottom plate portion 35 of the case body 31, for example.

[0031] 8 to 10, in this embodiment, the cover 32 is screwed to the bottom plate portion 35 via a plurality of threaded spacers 39. This point will be described below. Each threaded spacer 39 is mainly sandwiched between the circuit board 21 housed in the case body 31 and the top wall 37 of the lid 32. A male screw 391 is provided at the lower end of each threaded spacer 39 located on the circuit board 21 side (-Z side). Meanwhile, a female screw 392 is provided at the upper end of each threaded spacer 39 located on the lid 32 side (+Z side).

[0032] 8 and 9, the male threads 391 of each threaded spacer 39 are threaded into the female threads 352 of the support bosses 351 provided on the bottom plate portion 35. As a result, the circuit board 21 is fixed to the upper ends of the plurality of support bosses 351 by screwing. 9 and 10, with the lid 32 positioned so as to cover the opening 31A of the case body 31, the mounting screws 40 are passed through the top wall portion 37 of the lid 32 and screwed into the female threads 392 of each threaded spacer 39, thereby screwing the lid 32 to the threaded spacers 39. In this way, the lid 32 is screwed to the bottom plate portion 35 of the case body 31 via the threaded spacers 39.

[0033] 3 to 7, the side surface member 33 is attached to the inner surface of the case body 31. The side surface member 33 is disposed so as to overlap the inner surfaces of adjacent side plate portions 36 of the case body 31, thereby covering the gap G1 between the adjacent side plate portions 36. The side surface member 33 also covers the through-hole 362 of the second side plate portion 36B.

[0034] The side surface member 33 has a first plate portion 331 , a second plate portion 332 and a third plate portion 333 . The first plate portion 331 and the second plate portion 332 are arranged overlapping the inner surfaces of two adjacent side plates 36. Specifically, the first plate portion 331 is arranged overlapping the inner surface of the first side plate portion 36A, and the second plate portion 332 is arranged overlapping the inner surface of the second side plate portion 36B adjacent to the first side plate portion 36A. When the first and second plate portions 331, 332 are arranged overlapping the inner surfaces of the two adjacent side plates 36, the connection portion between the first plate portion 331 and the second plate portion 332 covers the gap G1 between the two adjacent side plates 36. In addition, the second plate portion 332 covers the through hole 362 of the second side plate portion 36B. In the illustrated example, the length of the second plate portion 332 in the Y direction is longer than the length of the first plate portion 331 in the X direction so that the second plate portion 332 covers the through hole 362 of the second side plate portion 36B. The first plate portion 331 and the second plate portion 332 are fixed to the inner surfaces of the first side plate portion 36A and the second side plate portion 36B by screws, respectively.

[0035] The third plate portion 333 is disposed so as to overlap the inner surface of the bottom plate portion 35. In the illustrated example, the third plate portion 333 is formed so as to be continuous with the lower end of the second plate portion 332, which is longer than the first plate portion 331. Note that the third plate portion 333 may also be formed so as to be continuous with the lower end of the first plate portion 331, for example. The third plate portion 333 is fixed to the inner surface of the bottom plate portion 35 by screwing.

[0036] In this embodiment, one side surface member 33 is provided for each gap G1 between adjacent side plate portions 36. Therefore, the case 3 of this embodiment includes four side surface members 33 corresponding to the four gaps G1, respectively. Note that one side surface member 33 may be provided for each of a plurality of gaps G1, for example. In other words, the number of side surface members 33 may be less than the number of gaps G1.

[0037] 1 and 2, the case 3 of this embodiment further has a terminal opening 34 that exposes the external connection terminals 22 of the circuit board unit 2 to the outside of the case 3. The terminal opening 34 is formed across the case body 31 and the lid 32. As shown in FIGS. 2 and 5, the terminal opening 34 is composed of a first notch 341 formed in the first side plate portion 36A of the case body 31 and a second notch 342 formed across the peripheral wall portion 38 (side plate portion 36) and the top wall portion 37 of the lid 32. Note that the terminal opening 34 may be formed in only one of the case body 31 and the lid 32, for example.

[0038] 1 and 2, the number and positions of the terminal openings 34 correspond to the number and positions of the external connection terminals 22 provided on the circuit board unit 2. That is, the number of terminal openings 34 in this embodiment is three. The terminal openings 34 include a first terminal opening 34A that is disposed at a first end of the circuit board 21 in the X direction and corresponds to the first connection terminal 22A of the circuit board unit 2, and two second terminal openings 34B that are disposed at a second end of the circuit board 21 in the X direction and respectively correspond to the two second connection terminals 22B of the circuit board unit 2.

[0039] 1 to 4, the electric circuit module 1 of this embodiment further includes a partitioning member 5. The partitioning member 5 partitions the housing space S of the case 3 into a first region S1 in which the external connection terminals 22 are arranged and a second region S2 excluding the first region S1 (see FIG. 2). Only the first region S1 actively communicates with the space outside the case 3 through the terminal openings 34.

[0040] The partitioning member 5 of this embodiment has elasticity similar to that of rubber or sponge. The partitioning member 5 is pressed against the circuit board 21 and the area around the edge of the terminal opening 34 on the inner surface of the case 3. This makes it possible to suppress or prevent gaps from forming between the partitioning member 5 and the circuit board 21 or the inner surface of the case 3. In other words, it is possible to suppress or prevent the first region S1 and the second region S2 from being connected to each other.

[0041] The above-mentioned partitioning member 5 includes a first partitioning member 5A that surrounds the first connection terminal 22A and a second partitioning member 5B that surrounds the two second connection terminals 22B. In the illustrated example, the same second partitioning member 5B surrounds the two second connection terminals 22B individually, but, for example, the same second partitioning member 5B may surround both second connection terminals 22B together. Also, for example, two second partitioning members 5B may surround each of the two second connection terminals 22B.

[0042] As shown in FIG. 2 , the electric circuit module 1 of this embodiment further includes a heat dissipation member 6. The heat dissipation member 6 is interposed between the inner surface of the case 3 and the heat-generating components 24 mounted on the circuit board 21, and transfers heat from the heat-generating components 24 to the case 3. The heat dissipation member 6 of this embodiment includes a first heat dissipation member 6A interposed between the circuit board unit 2 and the bottom plate 35 of the case body 31, and a second heat dissipation member 6B interposed between the circuit board unit 2 and the top wall 37 of the lid 32. The first heat dissipation member 6A transfers heat from the circuit board unit 2 to the bottom plate 35 of the case body 31. The second heat dissipation member 6B transfers heat from the circuit board unit 2 to the top wall 37 of the lid 32.

[0043] 2, the first heat dissipation member 6A contacts the heat-generating component 24 mounted on the second surface 21b of the circuit board 21. This allows the heat from the heat-generating component 24 to be efficiently conducted to the case body 31. The second heat dissipation member 6B contacts the heat-generating component 24 mounted on the first surface 21a of the circuit board 21. This allows the heat from the first electric component 23A to be efficiently conducted to the lid 32.

[0044] As described above, in the electric circuit module 1 of this embodiment, by covering the opening 31A of the case body 31 with the lid 32, it is possible to prevent dust from entering the inside of the case 3 through the opening 31A of the case body 31. Furthermore, by covering the gap G1 between the adjacent side plate portions 36 with the side surface members 33 arranged to overlap the inner surfaces of the adjacent side plate portions 36, it is possible to prevent dust from entering the inside of the case 3 through the gap G1. Therefore, it is possible to prevent dust from entering the inside of the case 3 that houses the circuit board unit 2.

[0045] Furthermore, in the electric circuit module 1 of this embodiment, the first and second plate portions 331, 332 of the side surface member 33 are respectively disposed to overlap the inner surfaces of the two adjacent side plate portions 36 of the case body 31 and are fixed by screws. Furthermore, the third plate portion 333 of the side surface member 33 is disposed to overlap the inner surface (top surface) of the bottom plate portion 35 of the case body 31 and is fixed by screws. Therefore, the side surface member 33 can prevent the bent portion between the side plate portions 36 and the bottom plate portion 35 of the case body 31 from opening (the case body 31 trying to return to a flat plate). Furthermore, gaps are prevented from being formed between the side surface member 33 and the inner surfaces of the two side plate portions 36 and the bottom plate portion 35 of the case body 31, and dust can be prevented from entering the inside of the case 3 through these gaps.

[0046] Furthermore, in the electric circuit module 1 of this embodiment, the side surface member 33 covers the through hole 362 that penetrates the second side plate portion 36B in its thickness direction as a result of the formation of the bent piece 361. This prevents dust from entering the inside of the case 3 through the through hole 362 of the second side plate portion 36B. Furthermore, compared to when the through hole 362 of the side plate portion 36B is covered with a separate member, the number of components of the case 3 can be reduced.

[0047] Furthermore, in the electric circuit module 1 of this embodiment, the storage space S of the case 3 is divided by the dividing member 5 into a first region S1 in which the external connection terminals 22 are arranged and a second region S2 excluding the first region S1. The dividing member 5 is pressed against the circuit board 21 and the region on the inner surface of the case 3 surrounding the edge of the terminal opening 34. This makes it possible to suppress or prevent dust from entering the interior of the case 3 (particularly the second region S2) through the terminal opening 34 of the case 3. Furthermore, because the partitioning member 5 has elasticity, even if an external force such as an impact acts on the case 3 from the outside, the external force can be absorbed by the partitioning member 5. This prevents the external force from acting on the circuit board unit 2 including the circuit board 21, thereby protecting the circuit board unit 2.

[0048] Furthermore, in the electric circuit module 1 of this embodiment, when the top wall 37 of the lid 32 covers the opening 31A of the case body 31, the peripheral wall 38 of the lid 32 overlaps the outer surfaces of the multiple side plate portions 36. This effectively prevents dust from entering the case 3 through gaps between the case body 31 and the lid 32 (particularly gaps between the top ends of the side plate portions 36 and the top wall 37) when the lid 32 covers the opening 31A of the case body 31.

[0049] Furthermore, in the electric circuit module 1 of this embodiment, the heat dissipation member 6 is interposed between the inner surface of the case 3 and the heat-generating components 24 of the circuit board unit 2. This allows the heat generated in the heat-generating components 24 to be efficiently dissipated to the case 3.

[0050] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and can be modified as appropriate within the scope of the invention.

[0051] In the present invention, the lid 32 may be configured by, for example, only the top wall portion 37, that is, may be formed in a flat plate shape.

[0052] In the present invention, the side member 33 does not have to include, for example, the third plate portion 333 .

[0053] The electric circuit module of the present invention may be provided in any device, for example, a projection display device that projects image light (image) onto a display surface such as a screen.

[0054] The electric circuit module (particularly the circuit board unit) of the present invention may be one having an electric circuit with any function, and may be, for example, a driver module that supplies power to various power-consuming components to drive those components. [Explanation of symbols]

[0055] 1 Electrical Circuit Module 2 Circuit board unit 3 cases 5 Compartment members 6 Heat dissipation material 21 Circuit Board 22 External connection terminal 24 Heat-generating components 31 Case body 31A Opening of case body 31 32 Lid 33 Side member 34 Terminal opening 35 Bottom plate part 36 Side plate part 37 Ceiling wall 38 Peripheral wall section 331 First plate part 332 Second plate part 333 Third plate part 361 Folded piece 362 Through hole 363 cutting line G1 Gap S Storage space S1 First area S2 second area

Claims

1. a circuit board unit and a case that houses the circuit board unit; the case includes a case body that opens in a predetermined direction and has an accommodation space for accommodating the circuit board unit, a lid that covers the opening of the case body, and a side member that is attached to the inner surface of the case body; the case body has a bottom plate portion having a polygonal shape in a plan view, and a plurality of side plate portions that are bent about each side of the bottom plate portion to extend from each side of the bottom plate portion to one side in a thickness direction of the bottom plate portion and form an opening of the case body, The side surface member is disposed so as to overlap at least the inner surfaces of the adjacent side plate portions, thereby covering the gap between the adjacent side plate portions.

2. the side surface member has a first plate portion and a second plate portion respectively disposed on the inner surfaces of the two adjacent side plate portions, and a third plate portion disposed on the inner surface of the bottom plate portion, the first plate portion and the second plate portion are fixed to the inner surfaces of the two adjacent side plate portions by screws, The electric circuit module according to claim 1 , wherein the third plate portion is fixed to the inner surface of the bottom plate portion by screws.

3. At least one of the side plate portions has a folded piece formed by folding a portion of the side plate portion surrounded by a cutting line toward the outside of the case body relative to other portions of the side plate portion, and a through hole penetrating the side plate portion in its thickness direction in association with the formation of the folded piece, The electric circuit module according to claim 1 or 2, wherein the side surface member covers the through hole of the side plate portion.

4. the circuit board unit includes a circuit board and an external connection terminal mounted on the circuit board; the case has a terminal opening for exposing the external connection terminal to the outside, a partition member that partitions the housing space of the case into a first area in which the external connection terminals are arranged and a second area of ​​the housing space excluding the first area, 3. The electric circuit module according to claim 1, wherein the partition member has elasticity and is pressed against the circuit board and the area of ​​the inner surface of the case surrounding the edge of the terminal opening.

5. the lid body has a top wall portion that covers the opening of the case body, and a peripheral wall portion that extends from a peripheral edge of the top wall portion to one side in a thickness direction of the top wall portion, 3. The electric circuit module according to claim 1, wherein the peripheral wall overlaps outer surfaces of the side plate portions when the top wall covers the opening of the case body.

6. the circuit board unit includes a circuit board and a heat-generating component mounted on the circuit board; 3. The electric circuit module according to claim 1, further comprising a heat dissipation member interposed between the inner surface of the case and the heat generating component to transfer heat from the heat generating component to the case.

7. A projection display device comprising the electric circuit module according to claim 1 or 2.

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