JP2016006448A - Rear projection projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rear projection projector capable of stably detecting light reflected from a detection target on a screen surface.SOLUTION: A rear projection projector 100 includes: a projection unit 10 for projecting projection light; a collimator lens 20 for converting the projection light into parallel light; a screen 30 having a back surface 31, to which the projection light collimated by the collimator lens 20 is incident, and a front surface 32, opposite the back surface 31, from which the projection light exits; and a light detection unit 40 for detecting light reflected by a detection target on the front surface 32 of the screen. The screen 30 is formed such that an angle θbetween the front surface 32 and the back surface 31 is an acute angle.

Description

  The present invention relates to a rear projection projector, and more particularly, to a rear projection projector including a light detection unit.

  2. Description of the Related Art Conventionally, a rear projection display device including a light detection unit is known (for example, see Patent Document 1).

  In Patent Document 1, a transmission screen that transmits light incident from the light incident surface side to the light emission surface side, an infrared light source that projects infrared light onto the transmission screen, and an operation that is emitted from the infrared light source and operated. A rear projection display device is disclosed that includes infrared light detection means (light detection unit) that detects reflected infrared light reflected on the light exit surface by the means.

JP 2012-108425 A

  However, in the rear projection display device described in Patent Document 1, not only light (signal light) is reflected by the operating means on the light exit surface (front surface) of the transmissive screen, but also the light incident surface (back surface) of the transmissive screen. ) Is also considered to reflect light (noise light). In this case, since the light (noise light) reflected by the light incident surface of the transmissive screen is detected as noise, the light (signal light) reflected by the input means on the light emitting surface of the transmissive screen is stably detected. There is a problem that it may not be possible.

  The present invention has been made to solve the above-described problems, and one object of the present invention is to stably detect light reflected by a detection object on the surface of the screen. It is to provide a rear projection type projector.

  A rear projection type projector according to one aspect of the present invention includes a projection unit for projecting projection light, an optical member for converting the projection light into parallel light, and the projection light converted into parallel light by the optical member on the back surface. And a light detection unit for detecting light reflected by the detection target on the surface of the screen, and the screen has a front surface and a back surface. Are non-parallel and the angle formed between the front surface and the back surface is an acute angle.

  In the rear projection type projector according to one aspect of the present invention, as described above, the screen is formed such that the front surface and the back surface are non-parallel and the angle between the front surface and the back surface is an acute angle. Thereby, the light (signal light) reflected by the detection target on the surface of the screen and the light (noise light) reflected on the back surface of the screen can be reflected in different directions on the back surface side of the screen. And by providing an optical member to make the projection light parallel light, the reflected light is collected opposite to the parallel light, so the signal reflected in different directions on the back side of the screen Light and noise light can be converged at different positions. As a result, signal light and noise light can be separated. Therefore, the signal light can be stably detected by the light detection unit. In addition, by providing an optical member for making the projection light parallel light, the signal light can be converged to a predetermined position, so that light (signal light) is detected by the detection target at any position on the surface of the screen. Even if it is reflected, the signal light can be reliably converged to a predetermined position. Further, since the projection light is collimated by the optical member, the brightness of the entire screen can be made substantially uniform. As a result, the visibility of the user can be improved.

  In the rear projection type projector according to the above aspect, the optical member is preferably provided in the vicinity of the back surface of the screen. If comprised in this way, a projection light can be made into parallel light with an optical member in the state in which the projection light projected from the projection part had enough breadth. In addition, the light (signal light) reflected by the detection object on the surface of the screen and the light (noise light) reflected on the back surface of the screen easily reach the optical member provided near the back surface of the screen. Can be made. As a result, the reflected signal light and noise light can be easily converged to different positions by the optical member.

  In the rear projection type projector according to the above aspect, the projection unit preferably includes a front surface and a back surface with respect to a normal line of the screen surface at the incident position on the front surface. Is disposed at a position where the first incident angle is incident on the surface of the screen from the tapering direction side. If comprised in this way, the light (signal light) reflected by the detection target object on the surface of a screen can be converged on the position different from the position of a projection part. As a result, unlike the case where the signal light converges at the position of the projection unit, the light detection unit can be easily arranged at a position where the signal light converges.

  In this case, it is preferable that the projection unit is configured so that the projection light collimated by the optical member has a front surface and a back surface that are tapered with respect to the normal line of the screen surface at the incident position on the front surface. At a first incident angle at a first incident angle and a second incident angle at the second incident angle from the opposite side to the direction in which the front surface and the back surface taper with respect to the normal of the back surface of the screen at the incident position on the back surface. It is arranged at the incident position. According to this configuration, the light (signal light) reflected by the detection target on the surface of the screen can be converged on one side with respect to the projection unit, and the light (noise) reflected on the back surface of the screen. Light) can be converged to the other side with respect to the projection unit. As a result, signal light and noise light can be more reliably separated.

  In the rear projection type projector according to the above aspect, the projection unit and the light detection unit are preferably arranged on a side opposite to the direction in which the front surface and the back surface taper from the normal passing through the approximate center of the screen surface. Has been. If comprised in this way, the projection light by a projection part can be incident on the back surface of a screen from the opposite side to the direction where a front surface and a back surface taper. As a result, the noise light can be easily converged in the direction in which the front surface and the back surface taper from the normal line passing through the approximate center of the screen surface. On the other hand, since the light detection unit is arranged on the opposite side to the direction in which the front surface and the back surface taper from the normal passing through the approximate center of the surface of the screen, the light detection unit and the convergence position of the noise light can be easily set. Can be separated. Therefore, it is possible to suppress detection of noise light by the light detection unit.

  In this case, preferably, the light detection unit is arranged on the opposite side to the direction in which the front surface and the back surface taper further than the position where the projection unit is arranged. If comprised in this way, a projection part can be arrange | positioned so that noise light may be interrupted | blocked between the position where noise light converges, and a light detection part. As a result, it is possible to further suppress the detection of noise light by the light detection unit.

  In the rear projection type projector according to the above aspect, the optical member preferably includes a lens member for making the projection light parallel light. With this configuration, the projection light can be converted into parallel light with a simple configuration, and the reflected signal light and noise light are converged at different positions, as opposed to parallel light. be able to.

  In this case, the lens member preferably includes a Fresnel lens. If comprised in this way, the thickness of a lens member can be made small. As a result, an increase in the size of the projector due to the provision of the lens member can be suppressed.

  According to the present invention, as described above, it is possible to provide a rear projection type projector that can stably detect the light reflected by the detection object on the surface of the screen.

It is a schematic diagram which shows the whole structure of the projector by 1st and 2nd embodiment of this invention. It is a block diagram which shows the structure of the projection part of the projector by 1st-3rd embodiment of this invention. It is a figure for demonstrating the incident state to the screen of the projection light of the projector by 1st Embodiment of this invention. It is a figure for demonstrating the convergence position of the noise light of the projector by 1st Embodiment of this invention. It is a figure for demonstrating the convergence position of the signal beam | light of the projector by 1st Embodiment of this invention. It is a figure for demonstrating the incident state to the screen of the projection light of the projector by 2nd Embodiment of this invention. It is a figure for demonstrating the convergence position of the signal beam | light of the projector by 2nd Embodiment of this invention. It is a figure for demonstrating the lens member of the projector by 3rd Embodiment of this invention.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings.

(First embodiment)
First, the configuration of a rear projection type projector 100 (hereinafter referred to as the projector 100) according to a first embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the projector 100 according to the first embodiment of the present invention includes a projection unit 10, a collimating lens 20, a screen 30, and a light detection unit 40. The projector 100 is a touch panel type projector that allows the user to operate the image displayed on the screen 30 with the detection object 90 (for example, the user's finger shown in FIG. 1). The collimating lens 20 is an example of the “optical member” and “lens member” in the present invention.

As shown in FIG. 1, the projection unit 10 is arranged in an inclined state with respect to the screen 30 so that projection light is incident on the back surface 31 of the screen 30 at a predetermined angle (θ ₁ described later). ing. Details of the arrangement of the projection unit 10 will be described later.

  As shown in FIG. 2, the projection unit 10 includes three (blue (B), green (G), and red (R)) laser light sources 11 (11 a, 11 b, and 11 c) and two beam splitters 12. (12a and 12b), a lens 13, a laser beam scanning unit 14, an image processing unit 15, a light source control unit 16, an LD (laser diode) driver 17, a mirror control unit 18, and a mirror driver 19. Contains.

  The laser light source 11 a is configured to irradiate the laser light scanning unit 14 with blue laser light through the beam splitter 12 a and the lens 13. The laser light sources 11b and 11c are configured to irradiate the laser beam scanning unit 14 with the green laser beam and the red laser beam through the beam splitters 12b and 12a and the lens 13, respectively.

  The laser beam scanning unit 14 is configured by a MEMS (Micro Electro Mechanical System) mirror. The laser beam scanning unit 14 is configured to scan the laser beam by reflecting the laser beam emitted from the laser light source 11 with a MEMS mirror. Specifically, the laser beam scanning unit 14 is configured to scan the laser beam on the screen 30 via the collimator lens 20.

  The video processing unit 15 is configured to control the projection of the video based on a video signal input from the outside. Specifically, the video processing unit 15 controls driving of the laser beam scanning unit 14 via the mirror control unit 18 based on a video signal input from the outside, and via the light source control unit 16. It is comprised so that irradiation of the laser beam by the laser light sources 11a-11c may be controlled.

  The light source control unit 16 is configured to control the LD driver 17 based on the control by the video processing unit 15 and to control the irradiation of the laser light from the laser light sources 11a to 11c. Specifically, the light source control unit 16 is configured to perform control to irradiate the laser light sources 11a to 11c with the laser light of the color corresponding to each pixel of the projection image in accordance with the scanning timing of the laser light scanning unit 14. Has been.

  The mirror control unit 18 is configured to control the mirror driver 19 based on the control by the video processing unit 15 to control the driving of the laser beam scanning unit 14.

  As shown in FIG. 1, the collimating lens 20 is provided near the back surface 31 of the screen 30 between the projection unit 10 and the screen 30. Further, the collimating lens 20 is configured so that the projection light (shown by a solid line) from the projection unit 10 is parallel light. Specifically, the collimating lens 20 is configured to refract the projected light having a spread within the collimating lens 20 to make parallel light parallel to each other. Further, the collimating lens 20 is configured to converge light reflected by the screen 30 (noise light and signal light, which will be described later), as opposed to making projection light parallel light.

  The screen 30 is composed of a transmissive screen, and is configured such that the projection light converted into parallel light by the collimator lens 20 is incident from the back surface 31 and is emitted from the surface 32 opposite to the back surface 31. As a result, the user can visually recognize an image corresponding to the projection light displayed on the surface 32. Here, the front surface 32 is a surface directed toward the user side, and the back surface 31 is a surface directed toward the side where the projection unit 10 is provided.

Here, in the first embodiment, as shown in FIG. 3, the screen 30 has a surface 32 and a back surface 31 that are non-parallel, and an angle formed between the surface 32 and the back surface 31 (θ _{2 in} FIG. 3). It is formed to have an acute angle. Specifically, the screen 30 has a wedge shape that gradually tapers in the Y2 direction, so that the front surface 32 and the back surface 31 are non-parallel, and the angle formed by the front surface 32 and the back surface 31 (FIG. 3). Of θ ₂ ) is an acute angle.

Further, in the first embodiment, as shown in FIGS. 1 and 3, the projection unit 10 has the projection light collimated by the collimating lens 20 on the side opposite to the direction in which the front surface 32 and the back surface 31 taper. in the position at an angle of incidence theta ₁ from (Y1 direction side) to the rear surface 31 of the screen 30 and the surface 32 and the back surface 31 and the incident angle from the direction (Y2 direction side) to the surface 32 of the screen 30 tapering theta _In FIG.

That is, the projection light incident on the back surface 31 of the screen 30 has an angle (incidence angle) formed with this normal line from the Y1 direction side relative to the normal line of the back surface 31 extending from the incident position of the projection light, θ _1. Incident. Similarly, the projection light incident on the surface 32 of the screen 30 has an angle (incident angle) formed with this normal from the Y2 direction side of the normal of the surface 32 extending from the incident position of the projection light to θ _3. Is incident on.

In the first embodiment, the projection unit 10 has a surface 32 rather than a normal (center line 50) passing through the approximate center of the screen 30 so that projection light can enter the screen 30 as described above. And the rear surface 31 are arranged on the opposite side (Y1 direction side) from the tapering direction. Here, the arrangement on the opposite side (Y1 direction side) to the direction in which the front surface 32 and the back surface 31 taper from the normal line (center line 50) passing through the approximate center of the screen 30 is slightly centerline. This includes the case where the position is shifted from 50. The incident angle θ ₃ is an example of the “first incident angle” in the present invention. The incident angle θ ₁ is an example of the “second incident angle” in the present invention.

Here, the incident angles θ ₁ and θ ₃ are set to values of about 5 degrees or less (for example, θ ₁ = 4 degrees, θ ₃ = 1.3 degrees). Thereby, even if the front surface 32 and the back surface 31 of the screen 30 are formed at an acute angle, it is possible to suppress an increase in the thickness of the screen 30, and thus it is possible to suppress an increase in the size of the projector 100. is there. In addition, by setting the value of θ ₃ to be small, the projection light can be incident on the surface 32 of the screen 30 at an angle close to vertical, so that the projection light can be emitted from the surface 32 at an angle close to vertical. It is. As a result, the projection light can be emitted in the direction in which the user often views the image from the front of the screen 30, so that the visibility of the user can be improved.

Further, the screen 30 is formed with an angle θ ₂ formed by the front surface 32 and the rear surface 31 so that the projection unit 10 can enter the projection light with respect to the screen 30 as described above. Specifically, the angle θ ₂ formed by the front surface 32 and the rear surface 31 satisfies θ ₂ > sin ⁻¹ (sin θ ₁ / n) where the refractive index of air is 1 and the refractive index of the screen is n. It is formed to have an acute angle. In FIG. 3, the relationship between the collimating lens 20 and the screen 30 is exaggerated to illustrate the incident angles θ ₁ and θ ₃ . Actually, the relationship between the collimating lens 20 and the screen 30 is as shown in FIG. 4 and FIG.

  As shown in FIG. 1, the light detection unit 40 includes a photodiode, and is provided to detect light reflected by the detection target 90 (signal light, indicated by a broken line). That is, the light detection unit 40 is provided for detecting a touch operation by the user. When the light (signal light) reflected by the detection target 90 is detected by the light detection unit 40, the projector 100 is configured to perform a predetermined operation. Further, the light detection unit 40 is arranged on the opposite side (Y1 direction side) from the direction in which the front surface 32 and the back surface 31 taper further than the position where the projection unit 10 is arranged.

  Next, the projection light reflected on the front surface 32 and the rear surface 31 of the screen 30 will be described with reference to FIGS. 4 and 5. Specifically, in FIG. 4, a convergence position of light (noise light) reflected on the back surface 31 of the screen 30 will be described. In FIG. 5, the convergence position of the light (signal light) reflected on the surface 32 of the screen 30 will be described.

First, as shown in FIG. 4, projection light is projected from the projection unit 10 onto the screen 30. Then, the projection light that is scanned by the projection unit 10 while having a predetermined divergence angle is incident on the collimator lens 20 and is converted into parallel light. Then, the projection light converted into parallel light by the collimating lens 20 is incident on the back surface 31 of the screen 30 at an incident angle θ ₁ (see FIG. 3). The main projection light is refracted by the back surface 31, passes through the screen 30, and is emitted from the front surface 32.

On the other hand, a part of the projection light is reflected on the back surface 31 of the screen 30. In FIG. 4, light (noise light) reflected on the back surface 31 of the screen 30 is indicated by a one-dot chain line. Here, the projection light incident on the back surface 31 at the incident angle θ ₁ from the Y1 direction side with respect to the normal line of the back surface 31 is reflected on the back surface 31 at the reflection angle θ ₁ and on the Y2 direction side with respect to the normal line of the back surface 31. Reflected. Therefore, the light (noise light) reflected on the back surface 31 of the screen 30 is reflected in a direction in which the angle is shifted by 2θ ₁ (see FIG. 3) with respect to the projection light from the projection unit 10. Then, the light (noise light) reflected on the back surface 31 of the screen 30 is converged to the noise light convergence position 61 on the Y2 direction side of the projection unit 10 by the collimator lens 20.

At this time, the projection light (projection light indicated by the solid line in the middle of FIG. 4) incident on the collimator lens 20 from the projection unit 10 and the light reflected on the back surface 31 (the middle of FIG. 4). The angle θ ₄ formed with the noise light indicated by the alternate long and short dash line can be expressed as 2θ ₁ when the refraction by the collimating lens 20 is ignored. When the distance from the projection unit 10 to the corresponding position of the screen 30 (the intersection of the projection light indicated by the solid line and the noise light indicated by the alternate long and short dash line) is d1, the noise light convergence position 61 is d1 more than the projection unit 10. Xtan (2θ ₁ ) is the position away from the Y2 direction. Since the noise light convergence position 61 can be adjusted by adjusting the value of θ ₁ , it is preferably determined by an experiment or the like as appropriate. Here, the distance from the projection unit 10 to the corresponding position on the back surface 31 of the screen 30 is d1, but when the distance from the collimating lens 20 to the screen 30 is sufficiently short, the distance d1 is set to the projection unit. The distance from 10 to the back surface of the collimating lens 20 (the surface on the projection unit 10 side) may be approximated. If approximated in this way, the noise convergence position can be obtained more easily.

  Next, the convergence position of light (signal light) reflected on the surface 32 of the screen 30 will be described with reference to FIG.

First, as shown in FIG. 5, projection light is projected from the projection unit 10 onto the screen 30. Then, the projection light converted into parallel light by the collimator lens 20 is incident on the back surface 31 of the screen 30 at an incident angle θ ₁ . The main projection light passes through the internal screen 30 while being refracted from the back 31, than the normal of the surface 32 is incident on the surface 32 of the screen 30 at an incident angle theta ₃ from direction Y2.

Then, the projection light incident on the surface 32 of the screen 30 at the incident angle θ ₃ from the Y2 direction side is reflected on the surface 32 by the detection target 90. In FIG. 5, three detection objects 90 are shown, and light (signal light) reflected by the three detection objects 90 on the surface 32 of the screen 30 is indicated by a broken line. Here, the projected light that is incident on the surface 32 at the incident angle theta _3, at surface 32, is specularly reflected on the Y1 direction side than the normal of the surface 32 at the reflection angle theta _3. Therefore, the light (signal light) reflected by the detection target 90 on the surface 32 of the screen 30 is reflected in a direction whose angle is shifted by 2θ _{3 with} respect to the projection light from the projection unit 10. Then, as shown in FIG. 3, the signal light is further adjusted so that the angle formed by the projection light and the signal light incident on the screen 30 is sin ⁻¹ (n × sin 2θ ₃ ) on the back surface of the screen 30. Refracted. Then, the signal light emitted from the screen 30 is converged by the collimator lens 20 to the signal light convergence position 62 on the Y1 direction side of the projection unit 10.

At this time, the projection light (projection light indicated by the solid line in the middle of FIG. 5) incident on the collimator lens 20 from the projection unit 10 and light reflected by the detection object 90 on the surface 32 (of the projection light). The angle θ ₅ formed with the signal light indicated by the broken line in the middle of FIG. 5 can be expressed as sin ⁻¹ (n × sin 2θ ₃ ) when refraction by the collimating lens 20 is ignored. Therefore, when the distance from the projection unit 10 to the corresponding position on the surface 32 of the screen 30 (the intersection of the projection light indicated by the solid line and the signal light indicated by the broken line) is d2, the signal light convergence position 62 is obtained from the projection unit 10. Is also a position separated in the Y1 direction side by d2 × tan (sin ⁻¹ (n × sin 2θ ₃ )). The light detection unit 40 is disposed at the signal light convergence position 62. Since the signal light convergence position 62 can be adjusted by adjusting the value of θ ₃ , it is preferably determined by experiments or the like as appropriate. Here, the distance from the projection unit 10 to the corresponding reflection position on the surface 32 of the screen 30 is d2, but when the distance from the collimating lens 20 to the screen 30 is sufficiently short, the distance d2 is set to the distance d1. Similarly, the distance from the projection unit 10 to the back surface of the collimator lens 20 (the surface on the projection unit 10 side) may be approximated. If approximated in this way, the signal convergence position can be obtained more easily, and the light detection unit 40 can be arranged at the signal convergence position.

  In this way, the projector 100 separates the light (noise light) reflected from the back surface 31 of the screen 30 and the light (signal light) reflected from the detection target 90 on the front surface 32 of the screen 30. Can do.

  In the first embodiment, the following effects can be obtained.

  In the first embodiment, as described above, the screen 30 is formed such that the front surface 32 and the back surface 31 are non-parallel and the angle formed by the front surface 32 and the back surface 31 is an acute angle. Thereby, the light (signal light) reflected by the detection target 90 on the surface 32 of the screen 30 and the light (noise light) reflected on the back surface 31 of the screen 30 are different in the back surface 31 side. Can be reflected. Then, by providing the collimating lens 20 for making the projection light parallel light, the reflected light is collected opposite to the parallel light, and is reflected in a different direction on the back surface 31 side of the screen 30. The made signal light and noise light can be converged at different positions (noise light convergence position 61 and signal light convergence position 62). As a result, signal light and noise light can be separated. Therefore, the signal light can be stably detected by the light detection unit 40. Further, by providing the collimating lens 20 for making the projection light into parallel light, the signal light can be converged to a predetermined position (signal light convergence position 62), so at any position on the surface 32 of the screen 30. Even if light (signal light) is reflected by the detection object 90, the signal light can be reliably converged to a predetermined position. Further, since the projection light is collimated by the collimating lens 20, the brightness of the entire screen 30 can be made substantially uniform. As a result, the visibility of the user can be improved.

  In the first embodiment, the collimating lens 20 is provided in the vicinity of the back surface 31 of the screen 30 as described above. Thereby, in the state in which the projection light projected from the projection unit 10 is sufficiently widened, the collimating lens 20 can make the projection light parallel light. Further, the light (signal light) reflected by the detection target 90 on the front surface 32 of the screen 30 and the light (noise light) reflected by the rear surface 31 of the screen 30 can be easily brought near the rear surface 31 of the screen 30. The collimating lens 20 provided can be reached. As a result, the reflected signal light and noise light can be easily converged to different positions by the collimating lens 20.

Moreover, in 1st Embodiment, as mentioned above, the projection light made into the parallel light by the collimating lens 20 with respect to the normal line of the surface 32 of the screen 30 of the incident position in the surface 32, the surface 32, the back surface 31, and The projection unit 10 is disposed at a position where the light enters the surface 32 of the screen 30 at an incident angle θ ₃ from the direction in which the taper tapers (Y2 direction). Thereby, the light (signal light) reflected by the detection target 90 on the surface 32 of the screen 30 can be converged to a position different from the position of the projection unit 10. As a result, unlike the case where the signal light converges at the position of the projection unit 10, the light detection unit 40 can be easily arranged at a position where the signal light converges.

Moreover, in 1st Embodiment, as mentioned above, the projection light made into the parallel light by the collimating lens 20 with respect to the normal line of the surface 32 of the screen 30 of the incident position in the surface 32, the surface 32, the back surface 31, and And the surface 32 with respect to the normal of the back surface 31 of the screen 30 at the incident position on the back surface 31 at the incident angle θ ₃ from the taper direction side (Y2 direction side). The projection unit 10 is arranged at a position where it enters the back surface 31 of the screen 30 at an incident angle θ ₁ from the side opposite to the direction in which the back surface 31 tapers (Y1 direction side). Thereby, the light (signal light) reflected by the detection target 90 on the front surface 32 of the screen 30 can be converged to one side with respect to the projection unit 10, and the light reflected on the back surface 31 of the screen 30. (Noise light) can be converged on the other side with respect to the projection unit 10. As a result, signal light and noise light can be more reliably separated.

  In the first embodiment, as described above, the direction (Y1 direction) is opposite to the direction in which the front surface 32 and the back surface 31 taper from the normal line (center line 50) passing through the approximate center of the front surface 32 of the screen 30. The projection unit 10 and the light detection unit 40 are disposed on the side. Thereby, since the projection light by the projection unit 10 can be incident on the back surface 31 of the screen 30 from the opposite side to the direction in which the front surface 32 and the back surface 31 taper, the normal line passing through the approximate center of the front surface 32 of the screen 30. Noise light can be easily converged on the direction side (Y2 direction side) in which the front surface 32 and the back surface 31 taper from (center line 50). On the other hand, since the light detection unit 40 is disposed on the opposite side to the direction in which the front surface 32 and the rear surface 31 taper from the normal line (center line 50) passing through the approximate center of the front surface 32 of the screen 30, The detection unit 40 and the noise light convergence position (noise light convergence position 61) can be separated from each other. Therefore, it is possible to suppress detection of noise light by the light detection unit 40.

  In the first embodiment, as described above, the light detection unit 40 is arranged on the opposite side of the direction in which the front surface 32 and the back surface 31 taper from the position where the projection unit 10 is arranged. Thereby, the projection part 10 can be arrange | positioned so that noise light may be interrupted between the position where noise light converges and the light detection part 40. As a result, the detection of noise light by the light detection unit 40 can be further suppressed.

  In the first embodiment, as described above, the projector 100 is provided with the collimating lens 20 for making the projection light parallel light. Thereby, the projection light can be made parallel light with a simple configuration, and the reflected signal light and the noise light are different from each other (as opposed to the parallel light) (noise light convergence position 61 and It can be converged to the signal light convergence position 62).

(Second Embodiment)
Next, a second embodiment will be described with reference to FIG. 1, FIG. 6, and FIG. In the second embodiment, unlike the first embodiment in which the projection light is incident on the surface 32 of the screen 30 at the incident angle θ ₃ , the projection light is substantially perpendicular to the surface 132 of the screen 130 (that is, θ ₃ is An example of incidence at substantially zero) will be described. In addition, about the structure same as the said 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

A rear projection projector 200 (hereinafter referred to as projector 200) according to the second embodiment of the present invention includes a screen 130 as shown in FIGS. Then, the projection unit 10 projects the projection light that has been collimated by the collimating lens 20 with respect to the screen 130 formed at the angle θ ₂₂ on the side opposite to the direction in which the front surface 32 and the rear surface 31 taper (Y1 direction). From the side) to the back surface 31 of the screen 130 at an incident angle θ ₁ . In FIG. 6, the relationship between the collimating lens 20 and the screen 130 is exaggerated in order to illustrate the incident angle θ ₁ . Actually, the relationship between the collimating lens 20 and the screen 130 is as shown in FIG.

In the second embodiment, the screen 130 is such that the front surface 132 and the back surface 31 are non-parallel, and the angle formed by the front surface 132 and the back surface 31 satisfies θ ₂₂ = sin ⁻¹ (sin θ ₁ / n). It is formed to have an acute angle. As in the first embodiment, θ ₁ is the incident angle of the projection light with respect to the back surface 31 of the screen 130, and n is the refractive index of the screen. In this case, as shown in FIG. 6, the projection light is incident on the surface 132 of the screen 130 substantially perpendicularly.

  In the second embodiment, the light detection unit 40 is disposed at a position overlapping the projection unit 10.

  Next, with reference to FIG. 7, the convergence position of the light (signal light) reflected by the surface 132 of the screen 130 of 2nd Embodiment is demonstrated.

  First, as shown in FIG. 7, the main component of the projection light projected from the projection unit 10 onto the screen 130 passes through the inside of the screen 130 while being refracted by the back surface 31, and the surface of the screen 130. Incidently incident on 132.

  Then, the projection light incident substantially perpendicularly on the surface 132 of the screen 130 is reflected on the surface 132 by the detection target 90. In FIG. 7, the reflected light (signal light) is indicated by a broken line. Here, the projection light incident on the surface 132 substantially perpendicularly is reflected on the surface 132 so as to follow the optical path of the projection light incident on the surface 132 in the reverse direction. Therefore, the light (signal light) reflected by the detection target 90 on the surface 132 of the screen 130 is converged on the position of the projection unit 10 by the collimator lens 20. And the light detection part 40 is arrange | positioned in the position which overlaps with the position (position of the projection part 10) where this signal light converges. In FIG. 7, for easy understanding, the light (signal light) reflected on the surface 132 is shown slightly shifted in the Y2 direction side from the optical path of the projection light incident on the surface 132.

  In addition, the other structure of 2nd Embodiment is the same as that of the said 1st Embodiment.

  In the second embodiment, the following effects can be obtained.

  In the second embodiment, as described above, the screen 130 is formed so that the front surface 132 and the back surface 31 are non-parallel and the angle formed by the front surface 132 and the back surface 31 is an acute angle. As a result, similarly to the first embodiment, the light detection unit 40 can stably detect the signal light.

  In the second embodiment, as described above, the projector 200 is configured so that the projection light is incident on the surface 132 of the screen 130 substantially perpendicularly. Thereby, projection light can be emitted in the direction in which the user who often visually recognizes an image from the front of the screen 130 is present, so that the visibility of the user can be further improved.

  The remaining effects of the second embodiment are similar to those of the aforementioned first embodiment.

(Third embodiment)
Next, a third embodiment will be described with reference to FIG. In the third embodiment, unlike the first and second embodiments in which the collimating lens 20 is used to make the projection light parallel, an example in which the Fresnel lens 220 is used to make the projection light parallel. explain. In addition, about the structure same as the said 1st and 2nd embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  A rear projection type projector 300 according to the third embodiment of the present invention includes a Fresnel lens 220 for making the projection light from the projection unit 10 parallel light as shown in FIG. The Fresnel lens 220 has such a shape that the arc-shaped surface of the collimating lens 20 is divided and arranged on a plane, and is formed to have a thickness smaller than that of the collimating lens 20. The Fresnel lens 220 is an example of the “optical member” and “lens member” in the present invention.

  The Fresnel lens 220 of the third embodiment also converges the light (signal light and noise light) reflected on the back surface 31 and the front surface 32 of the screen 30 as opposed to making the projection light parallel light. It is configured as follows.

  The remaining configuration of the third embodiment is similar to that of the aforementioned first embodiment.

  In the third embodiment, the following effects can be obtained.

  In the third embodiment, as described above, the projector 300 is provided with the Fresnel lens 220. Thereby, compared with the case where a collimating lens is provided like the said 1st and 2nd embodiment, the thickness of a lens member can be made small. As a result, the projector 300 can be prevented from being enlarged due to the provision of the lens member.

  The remaining effects of the third embodiment are similar to those of the aforementioned first embodiment.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiment but by the scope of claims for patent, and further includes all modifications (modifications) within the meaning and scope equivalent to the scope of claims for patent.

For example, in the first embodiment, the angle θ ₂ formed between the front surface 32 and the rear surface 31 of the screen 30 is an acute angle that satisfies θ ₂ > sin ⁻¹ (sin θ ₁ / n), and the second embodiment described above. In the embodiment, the example in which the angle θ ₂₂ formed between the front surface 132 and the rear surface 31 of the screen 130 is an acute angle satisfying θ ₂₂ = sin ⁻¹ (sin θ ₁ / n) is shown. Not limited. In the present invention, the angle θ formed between the front surface and the back surface of the screen may be formed other than the above angle. For example, an acute angle satisfying θ <sin ⁻¹ (sin θ ₁ / n) may be formed. In this case, although the noise light convergence position and the signal light convergence position are on the same side with respect to the projection unit 10, the noise light convergence position and the signal light convergence position can be separated.

  Moreover, in the said 1st-3rd embodiment, although the example using the collimating lens 20 and the Fresnel lens 220 was shown as an optical member of this invention, this invention is not limited to this. In the present invention, an optical member other than a collimator lens or a Fresnel lens may be used as the optical member. For example, a mirror member may be used as the optical member.

  Moreover, although the collimating lens 20 (Fresnel lens 220) was provided in the back surface 31 vicinity of the screen 30 (130) in the said 1st-3rd embodiment, this invention is not limited to this. In the present invention, an optical member such as a collimator lens or a Fresnel lens may be provided at a position other than the vicinity of the back surface of the screen.

In the first and second embodiments, the projection light is incident on the back surface 31 of the screen 30 at the incident angle θ ₁ from the opposite side (Y1 direction side) to the direction in which the front surface 32 (132) and the back surface 31 taper. Although the example which has arrange | positioned the projection part 10 to the position which enters is shown, this invention is not limited to this. In the present invention, the projection unit may be disposed at a position other than the position where the projection light is incident at an incident angle θ ₁ with respect to the back surface of the screen from the side opposite to the direction in which the front surface and the back surface taper. For example, the projection unit may be arranged at a position where the projection light is incident substantially perpendicular to the back surface of the screen.

  Moreover, in the said 1st Embodiment, the example which has arrange | positioned the photon detection part 40 on the opposite side (Y1 direction side) from the direction where the surface 32 and the back surface 31 taper further from the position where the projection part 10 is arrange | positioned. However, the present invention is not limited to this. In this invention, you may arrange | position a photon detection part in the direction side in which a surface and a back surface taper rather than the position where a projection part is arrange | positioned.

  Moreover, although the example which has arrange | positioned the photon detection part 40 in the position which overlaps with the projection part 10 was shown in the said 2nd Embodiment, this invention is not limited to this. In the present invention, the light detection unit 40 may be disposed at a position other than the position overlapping the projection unit 10. For example, the light detection unit 40 may be disposed in the vicinity of the projection unit 10. In FIG. 7, only the component due to specular reflection is shown in the light (signal light) reflected by the detection target 90 on the surface 132 of the screen 130, but actually it is reflected by diffuse reflection in addition to the specular reflection. There is also light. Therefore, if the light detection unit 40 is arranged in the vicinity of the projection unit 10 shown in FIG. 7, the light reflected from the detection target 90 on the surface 132 of the screen 130 (signal light) corresponds to a component due to diffuse reflection. The signal light to be detected can be detected. Also in this case, since the noise light is separated, it is possible to detect the signal light stably by the light detection unit 40.

10 Projection unit 20 Collimating lens (optical member, lens member)
30, 130 Screen 31 Back 32, 132 Front 40 Photodetection unit 100, 200, 300 Rear projection projector 220 Fresnel lens (optical member, lens member)

Claims (8)

A projection unit for projecting projection light;
An optical member for making the projection light parallel light;
The projection light converted into parallel light by the optical member is incident from the back surface, and is emitted from the surface opposite to the back surface;
A light detection unit for detecting light reflected by the detection object on the surface of the screen,
The rear projection type projector, wherein the screen is formed such that the front surface and the back surface are non-parallel, and an angle formed between the front surface and the back surface is an acute angle.   The rear projection projector according to claim 1, wherein the optical member is provided in the vicinity of the back surface of the screen.   The projection unit is configured such that the projection light collimated by the optical member is from the direction side in which the front surface and the back surface taper with respect to the normal line of the surface of the screen at the incident position on the front surface. The rear projection type projector according to claim 1, wherein the rear projection type projector is disposed at a position incident on the surface of the screen at a first incident angle.   The projection unit is configured such that the projection light collimated by the optical member is from the direction side in which the front surface and the back surface taper with respect to the normal line of the surface of the screen at the incident position on the front surface. From the side opposite to the direction in which the front surface and the back surface taper with respect to the normal of the back surface of the screen at the incident position on the back surface at a position incident on the front surface of the screen at a first incident angle. The rear projection projector according to claim 3, wherein the rear projection projector is disposed at a position incident on the back surface of the screen at a second incident angle.   The said projection part and the said light detection part are arrange | positioned on the opposite side to the direction where the said surface and the said back surface taper rather than the normal line which passes along the approximate center of the said surface of the said screen. The rear projection type projector according to any one of the above.   6. The rear projection type projector according to claim 5, wherein the light detection unit is disposed on a side opposite to a direction in which the front surface and the back surface taper further than a position where the projection unit is disposed.   The rear projection type projector according to claim 1, wherein the optical member includes a lens member for making the projection light parallel light.   The rear projection type projector according to claim 7, wherein the lens member includes a Fresnel lens.

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