JP7740449B2 - projector - Google Patents

Description

The present invention relates to a projector, particularly a projector for use in a vehicle interior.

Conventionally, a vehicle lamp has been known that includes a condensing lens that condenses light emitted from a light source, a light-blocking member that partially transmits the light condensed by the condensing lens, and a projection lens that projects the light that has passed through the light-blocking member to form an illumination pattern (see Patent Document 1).

In the vehicle lamp described in Patent Document 1, the condenser lens, filter, and projection lens are housed in a housing and are fitted and fixed into the condenser lens groove, filter groove, and projection lens groove in the housing, respectively.

Japanese Patent Application Laid-Open No. 2020-205237

However, in the vehicle lamp described in Patent Document 1, the focusing lens, filter, and projection lens are each fixed in position by the housing, which means that the relative positioning accuracy of the focusing lens, filter, and projection lens is poor, and there is a risk that the projected image will be unclear. Furthermore, there is a risk that foreign matter such as dust may enter the space where the filter is installed from the outside through the gap between the focusing lens and the housing in the focusing lens groove, or the gap between the projection lens and the housing in the projection lens groove, and that the foreign matter may be reflected in the projected image.

The object of the present invention is to provide a projector that can project clear images with reduced foreign object reflection.

In order to achieve the above object, one aspect of the present invention provides the following projectors [1] to [4].

[1] A projector comprising: a light source that emits light; a pattern plate having light-transmitting portions and light-shielding portions that constitute a pattern for projection; and a lens component including a projection lens for projecting the pattern of the pattern plate; wherein at least a portion of the pattern of the pattern plate has a fine portion formed by the light-transmitting portions and the light-shielding portions, and in which a fine pattern exceeding the resolution of the projection lens is formed; and wherein the fine portion forms an area in the projected image having a brightness between a first brightness and a second brightness, wherein the first brightness is the brightness of the area formed by a portion of the light-transmitting portion when the portion of the light-shielding portion constitutes a portion of the pattern other than the fine portion, and the second brightness is the brightness of the area formed by the portion of the light-shielding portion when the portion of the light-shielding portion constitutes a portion of the pattern other than the fine portion.
[2] The projector according to [1] above, wherein the minimum width of the light-shielding portion is less than 10 μm.
[3] The projector according to [1] or [2], wherein the projected image displays a gradation by arranging areas of different brightness.
[4] The projector according to [1] or [2], wherein the projected image is a three-dimensional representation in which different surfaces of a three-dimensional object are represented by areas of different brightness.

This invention provides a projector that can project clear images with reduced foreign object reflection.

1A and 1B are perspective views of a projector according to an embodiment of the invention, viewed from different angles. Figure 2(a) is a side view of a projector according to an embodiment of the present invention as viewed from the light extraction side, and Figure 2(b) is a cross-sectional view of the projector taken along the cutting line A-A shown in Figure 2(a). FIG. 3 is an exploded perspective view of the projector according to the embodiment of the invention. 4A to 4D are perspective views showing the process of assembling the first lens component, the handle plate, and the second lens component to the housing components. FIG. 5A is a cross-sectional view of the housing component, the first lens component, and the second lens component taken along the cutting line BB shown in FIG. 4D. FIG. 6 is a vertical cross-sectional view of one form of a handle plate according to an embodiment of the present invention. Figure 7(a) is a schematic diagram showing an example of a pattern on a pattern plate in an embodiment of the present invention, and Figure 7(b) is a schematic diagram showing a projected image onto which the pattern of Figure 7(a) is projected. FIG. 8 is a vertical cross-sectional view of another embodiment of the handle plate according to the present invention. FIG. 9 is a schematic diagram for explaining the conditions under which total reflection occurs when the light-shielding portion of the handle plate is formed of a protrusion including two opposing inclined surfaces. 10(a), (b), and (c) are schematic diagrams showing the optical paths of light that enters the pattern plate when the angle _θt is 90°, 140°, and 40°, respectively.

[Embodiment]
1A and 1B are perspective views of a projector 1 according to an embodiment of the invention, viewed from different angles. Fig. 2A is a side view of the projector 1 viewed from the light extraction side, and Fig. 2B is a cross-sectional view of the projector 1 taken along the line A-A in Fig. 2A. Fig. 3 is an exploded perspective view of the projector 1.

Projector 1 is primarily used inside a vehicle and is attached, for example, to the vehicle's interior side panels, instrument panel, or doors, and projects images onto the doors, floor mats, ceiling, and decorative panels and ornaments included in the instrument panel, door trim, etc.

Projector 1 comprises a light source 11 that emits light, a pattern plate 20 that has a pattern for projection, a first lens component 21 that includes a condenser lens 211 that collects the light emitted from light source 11 and sends it to pattern plate 20, and a second lens component 22 that includes a projection lens 221 for projecting the pattern on pattern plate 20. In projector 1, first lens component 21 and second lens component 22 securely sandwich pattern plate 20 inside first lens component 21 and second lens component 22 so that it is sealed.

The light source 11 is a light-emitting element equipped with an LED chip or the like. The light source 11 is mounted on a circuit board 10, to which a connector 12 is connected for transmitting power and signals to the light source 11.

The circuit board 10 on which the light source 11 is mounted, the first lens component 21, the second lens component 22, and the handle plate 20 are housed in a housing 30 composed of components 30a, 30b, and 30c. The housing 30 has an opening 301 for extracting light from the projection lens 221 and an opening 302 for connecting an external device connector to the connector 12. The housing 30 is made of a resin such as polybutylene terephthalate (PBT) resin, polypropylene (PP) resin, or ABS resin.

Components 30a and 30b are fixed together by snap-fitting protrusions 305 on both sides of component 30b into holes 304 in component 30a. Components 30a and 30c are fixed together by snap-fitting protrusions 307 on both sides of component 30c into holes 306 in component 30a. Circuit board 10 is sandwiched and fixed between components 30a and 30c.

The first lens component 21 has a condenser lens 211, a frame 212 having a box-like shape (e.g., a rectangular parallelepiped) with one open side, and a fixing portion 215 for fixing the first lens component 21 to the second lens component 22 and the housing component 30b. The condenser lens 211 is located in a plane opposite the open surface of the frame 212. The first lens component 21 is made of a resin such as polycarbonate (PC) resin or polymethyl methacrylate (PMMA) resin.

The second lens component 22 has a projection lens 221, a frame 222 having a box-like shape (e.g., a rectangular parallelepiped) with one open side, and a fixing portion 225 for fixing the second lens component 22 to the first lens component 21 and the housing component 30b. The projection lens 221 is located in a plane opposite the open surface of the frame 222. The second lens component 22 is made of a resin such as polycarbonate resin or polymethyl methacrylate resin.

In the projector 1, the first lens component 21 and the second lens component 22 are fixed in place with the opening surfaces of the frame portions 212 and 222 facing each other, and with the end surface 213, which is the edge of the opening surface of the frame portion 212, and the end surface 223, which is the edge of the opening surface of the frame portion 222, tightly in contact around the entire periphery. This seals the space inside the first lens component 21 and the second lens component 22, including the handle plate 20. It is preferable that the end surfaces 213 and 223 be polished to improve adhesion.

When the first lens component 21 and the second lens component 22 are brought into close contact, the portions 214 that protrude inward from the four corners of the internal space of the frame 212 and the portions 224 that protrude inward from the four corners of the internal space of the frame 222 sandwich and secure the four corners of the handle plate 20 from the front and back.

Figures 4(a) to 4(d) are perspective views showing the process of assembling the first lens component 21, the handle plate 20, and the second lens component 22 to the component 30b of the housing 30.

First, as shown in Figures 4(a) and (b), the second lens component 22 is assembled to component 30b of the housing 30. With the opening of the frame portion 222 facing upward, the fixing portion 225 is fitted into component 30b of the housing 30.

Next, as shown in Figures 4(b) and (c), the handle plate 20 is fitted into the opening of the frame portion 222 of the second lens component 22. The handle plate 20 is fitted into the opening of the frame portion 222 so that it rests on the portion 224 inside the frame portion 222 of the second lens component 22.

Next, as shown in Figures 4(c) and (d), the first lens component 21 is assembled to the housing component 30b. With the opening of the frame 212 facing downward, the fixing component 215 is fitted into the housing component 30b. At this time, the protrusions 226 on the fixing component 225 of the second lens component 22 are fitted into the holes 216 on the fixing component 215 of the first lens component 21. Furthermore, when the fixing component 215 is fitted into the component 30b, the protrusions 217 on both sides of the fixing component 215 snap-fit into the holes 303 on the component 30b.

Figure 5(a) is a cross-sectional view of the housing 30 component 30b, the first lens component 21, and the second lens component 22 taken along the cutting line B-B shown in Figure 4(d).

As shown in Figure 5(a), the second lens component 22 compresses the protrusion 308 on the inner bottom surface of component 30b from above, causing elastic deformation, and is subjected to an upward repulsive force from the protrusion 308. Meanwhile, the protrusion 217 of the first lens component 21 is caught in the hole 303, preventing the first lens component 21 and the second lens component 22 from moving upward, and therefore the first lens component 21 and the second lens component 22 are fixed to component 30b.

Figure 5(b) is a cross-sectional view of the first lens component 21, the second lens component 22, and the handle plate 20 taken along the cutting line C-C shown in Figure 4(d).

As shown in Figure 5(b), the first lens component 21 and the second lens component 22 are fixed in place with the end face 213, which is the edge of the opening of the frame portion 212, and the end face 223, which is the edge of the opening of the frame portion 222, in close contact with each other, sealing the internal spaces of the first lens component 21 and the second lens component 22. Furthermore, the handle plate 20 is fixed by being sandwiched between the portions 214, which protrude inward from the four corners of the internal space of the frame portion 212, and the portions 224, which protrude inward from the four corners of the internal space of the frame portion 222.

In the projector 1, the first lens component 21, the second lens component 22, and the handle plate 20 are fixed in close contact with each other, resulting in high relative positioning accuracy between the condenser lens 211 included in the first lens component 21, the projection lens 221 included in the second lens component 22, and the handle plate 20. This prevents the projected image from becoming unclear due to relative misalignment between the condenser lens 211, the projection lens 221, and the handle plate 20.

In addition, because the internal spaces of the first lens component 21 and the second lens component 22 are sealed, it is possible to prevent foreign matter such as dust from entering the area around the handle plate 20. This makes it possible to prevent foreign matter from appearing in the projected image.

The method for fixing the first lens component 21, the second lens component 22, and the handle plate 20 in close contact with each other is not limited to the method using a snap fit with the component 30b described above; for example, the first lens component 21 and the second lens component 22 may be fixed with an adhesive.

Figure 6 is a vertical cross-sectional view of pattern plate 20a, one form of pattern plate 20. Pattern plate 20a includes a transparent substrate 201 that transmits light from light source 11, and an opaque film 202 that does not transmit light from light source 11. The opaque film 202 has a predetermined opening pattern that forms the pattern of pattern plate 20a, and has light-transmitting portions 203 that are openings and light-shielding portions 204 that are not openings.

The image projected by projector 1 is composed of high-brightness areas with a pattern corresponding to the pattern of the light-transmitting portions 203 and low-brightness areas with a pattern corresponding to the pattern of the light-shielding portions 204.

To form a fine opening pattern in the opaque film 202 and create a finer pattern on the pattern plate 20a, it is preferable to form the pattern by metal etching on the opaque film 202, which is made of a metal and deposited on the transparent substrate 201 made of glass. By depositing the metal film by vapor deposition, a very thin (approximately 100 nm) opaque film 202 can be obtained, and the pattern can be formed with high precision by etching.

In this case, the opaque film 202 is, for example, a laminated film of an opaque film 202a made of CrO and an opaque film 202b made of Cr. Furthermore, for example, the thicknesses of the opaque film 202, the opaque film 202a, and the opaque film 202b are 1.1 mm, 8 nm, and 62 nm, respectively, and the planar size of the pattern plate 20 is 8 mm x 8 mm.

When forming a pattern on an opaque film 202 made of metal deposited on a transparent substrate 201 made of glass, the minimum width of the patterned opaque film 202 (the minimum width of the light-shielding portion 204 with light-transmitting portions 203 formed on both sides) can be set to 1 μm or more and less than 10 μm, or more precisely, 1 μm or more and 5 μm or less.

Furthermore, if the pattern on the pattern plate 20a includes fine details that exceed the resolution of the projection lens 221, those fine details will not be resolved even in a focused projected image. Specifically, in the projected image, the boundaries between the high-brightness areas formed by the light-transmitting portions 203 and the low-brightness areas formed by the light-shielding portions 204 will become invisible, and the high-brightness and low-brightness areas will blend together, leaving visible an area with a brightness between those two (lower than the brightness of the resolved high-brightness areas and higher than the brightness of the resolved low-brightness areas).

In other words, by using the fine details contained in the pattern of the pattern plate 20a that are not resolved in a focused projected image, it is possible to express a brightness in the projected image that is between the brightness of the part formed by the light-transmitting part 203 and the brightness of the part formed by the light-blocking part 204.

Figure 7(a) is a schematic diagram showing an example of a pattern on pattern plate 20a, and Figure 7(b) is a schematic diagram showing a projected image of the pattern of Figure 7(a). The line-and-space pattern (second triangle from the left and top surface of the cube) and dot pattern (third triangle from the left and side surface of the cube) included in the pattern of Figure 7(a) are so fine that they exceed the resolution of the projection lens 221. In the projected image shown in Figure 7(b), the area formed by these fine patterns is visually recognized as a gray area with a brightness between the white of the area formed by light-transmitting portion 203 (first triangle from the left and front surface of the cube) and the black of the area formed by light-shielding portion 204 (base portion). In this way, a gradation effect, as shown by the difference in brightness of the three triangles in Figure 7(b), and a three-dimensional effect, as exemplified by the cube in Figure 7(b), can be achieved.

Furthermore, if a fine pattern can be formed on the opaque film 202, the pattern plate 20 can be made smaller. Since the size of the projected image is calculated by multiplying the size of the pattern on the pattern plate 20 by the magnification factor of the optical system, if the pattern plate 20 can be made smaller, the magnification factor can be increased while maintaining the size of the projected image. Therefore, by reducing the distance between the pattern plate 20 and the projection lens 221 (increasing the magnification factor), the projector 1 can be made smaller. In other words, by making the pattern plate 20 smaller, the projector 1 can be made smaller while maintaining the size of the projected image. For example, the width W1 of the projector 1 in the optical axis direction can be set to 35 mm or less, the width _W2 in the direction perpendicular to the optical axis direction can _be set to 13 mm or less, and the angle of view can be set to 20° or more.

Figure 8 is a vertical cross-sectional view of handle plate 20b, another form of handle plate 20. Handle plate 20b is made of transparent resin that transmits light from light source 11, and has, on one side, a light-transmitting portion 207 composed of a flat surface 205 and a light-shielding portion 208 composed of an inclined surface 206 that is inclined relative to the flat surface.

The light-shielding portion 208 blocks light from the light source 11 by utilizing total reflection of light at the inclined surface 206. Therefore, the inclination angle of the inclined surface 206 is set so that light incident perpendicularly on the handle plate 20b is totally reflected. As a result, light does not pass through the light-shielding portion 208 formed by the inclined surface 206. For example, if the handle plate 20b is made of polycarbonate (refractive index 1.6), total reflection occurs when the angle of incidence is 38.7° or greater, and if it is made of polymethyl methacrylate (refractive index 1.5), total reflection occurs when the angle of incidence is 41.8° or greater.

The image projected by projector 1 is composed of high-brightness areas with a pattern corresponding to the pattern of the light-transmitting portion 207 and low-brightness areas with a pattern corresponding to the pattern of the light-shielding portion 208.

The handle plate 20b is formed by micro-machining a plate-shaped resin molded product. Therefore, compared to the handle plate 20a, which requires complex processes such as metal film deposition, resist pattern formation using photolithography, and etching, the handle plate 20b can be formed more inexpensively.

The light-shielding portion 208 is provided with a protrusion formed by an inclined surface 206. The protrusion formed by the inclined surfaces 206 is, for example, a linear protrusion with a triangular cross section formed by two opposing inclined surfaces 206, or a polygonal pyramidal protrusion formed by three or more inclined surfaces 206. Note that if the height of the protrusion is limited by factors such as the transferability during molding of the handle plate 20b (for example, 30 μm or less), multiple low protrusions can be arranged in succession to ensure the area of the light-shielding portion 208.

9 is a schematic diagram for explaining the conditions for total reflection when the light-shielding portion 208 of the pattern plate 20b is composed of a protrusion including two opposing inclined surfaces 206 (for example, a linear protrusion or a quadrangular pyramidal protrusion whose cross section formed by the two opposing inclined surfaces 206) is used. Here, the angle of incidence of light that enters the pattern plate 20b perpendicularly onto the first incident inclined surface 206 (assumed to be inclined surface 206a) _{is θ1} , the angle of incidence of the light reflected by inclined surface 206a onto the next incident inclined surface (assumed to be inclined surface 206b) is _θ2 , and the angle of the cross section of the apex of the protrusion is _θt .

In order for light that enters the pattern plate 20b perpendicularly to be totally reflected by the inclined surface 206a, if the pattern plate 20b is made of polycarbonate, _θ1 must be 38.7° or more, in which case _θt will be 102.6° or less. If the pattern plate 20b is made of polymethyl methacrylate, _θ1 must be 41.8° or more, in which case _θt will be 96.4° or less.

Furthermore, in order for the light totally reflected by the inclined surface 206a to be totally reflected by the inclined surface 206b, if the pattern plate 20b is made of polycarbonate, _θ2 must be 38.7° or more, in which case _θt is 85.8° or more. Also, if the pattern plate 20b is made of polymethyl methacrylate, _θ2 must be 41.8° or more, in which case _θt is 87.9° or more.

Therefore, when the handle plate 20b is made of polycarbonate, it is preferable to set the angle _θt of the cross section of the apex of the protrusion to 85.8° or more and 102.6° or less in order to effectively block light in the light shielding portion 208. Also, when the handle plate 20b is made of polymethyl methacrylate, it is preferable to set the angle _θt of the cross section of the apex of the protrusion to 87.9° or more and 96.4° or less in order to effectively block light in the light shielding portion 208.

10(a) is a schematic diagram showing the optical path of light entering the handle plate 20b at an angle _θt of 90°. In this case, light that enters the handle plate 20b perpendicularly is incident on the inclined surface 206a at an incident angle of 45° and is totally reflected, and then is incident on the inclined surface 206b at an incident angle of 45° and is totally reflected, returning to the light source 11. Since protrusions with an angle _θt of 90° can be formed using a common tool, it can be said that the angle _θt is particularly preferably 90°.

10B is a schematic diagram showing the optical path of light entering the pattern plate 20b at an angle _θt of 140°. In this case, the light that enters the pattern plate 20b perpendicularly is incident on the inclined surface 206a at an incident angle of 20°, and part of the light is refracted by the inclined surface 206a and passes through the pattern plate 20b.

10(c) is a schematic diagram showing the optical path of light entering the pattern plate 20b at an angle _θt of 40°. In this case, the light that enters the pattern plate 20b perpendicularly is incident on the inclined surface 206a at an incident angle of 70° and is totally reflected, but then it is incident on the inclined surface 206b at an incident angle of 30°, and part of it is refracted by the inclined surface 206b and passes through the pattern plate 20b.

(Effects of the embodiment)
In the projector 1 according to the embodiment of the present invention described above, the first lens component 21, the second lens component 22, and the handle plate 20 are fixed in close contact with each other, so the relative positioning accuracy of the condenser lens 211 included in the first lens component 21, the projection lens 221 included in the second lens component 22, and the handle plate 20 is high. This makes it possible to prevent the projected image from becoming unclear due to relative positional misalignment of the condenser lens 211, the projection lens 221, and the handle plate 20. Furthermore, because the internal spaces of the first lens component 21 and the second lens component 22 are sealed, it is possible to prevent foreign matter such as dust from entering the periphery of the handle plate 20. This makes it possible to prevent foreign matter from appearing in the projected image.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and various modifications are possible without departing from the spirit of the invention. Furthermore, the components of the above embodiments can be combined in any manner without departing from the spirit of the invention.

Furthermore, the above-described embodiments do not limit the scope of the claimed invention. It should also be noted that not all of the combinations of features described in the embodiments are necessarily essential to the means for solving the problems of the invention.

REFERENCE SIGNS LIST 1 Projector 11 Light source 20 Handle plate 21 First lens component 211 Condenser lens 212 Frame 22 Second lens component 221 Projection lens 222 Frame 30 Housing

Claims (4)

a light source that emits light;
a pattern plate having a light-transmitting portion and a light-shielding portion that constitute a pattern for projection;
a lens component including a projection lens for projecting the pattern of the pattern plate;
Equipped with
a fine pattern formed on at least a part of the pattern of the pattern plate, the fine pattern being composed of the light transmitting portion and the light blocking portion, and the light transmitting portions arranged on either side of the light blocking portion being in a position that cannot be separated by the resolution of the projection lens;
the fine portion forms an area in the projected image having a brightness between a first brightness and a second brightness;
the first brightness is a brightness of a region formed by a part of the light-transmitting portion when the part of the light-transmitting portion constitutes a part other than the fine part of the pattern,
the second brightness is the brightness of a region formed by a part of the light-shielding portion when the part of the light-shielding portion constitutes a part other than the fine part of the pattern;
projector. The minimum width of the light-shielding portion is 1 μm or more and less than 10 μm.
The projector according to claim 1 . In the projected image, a gradation representation is performed by arranging areas of different brightness.
The projector according to claim 1 or 2. In the projected image, a three-dimensional representation is performed in which different surfaces of the three-dimensional object are represented by areas of different brightness.
The projector according to claim 1 or 2.