JP7552184B2 - Projection equipment - Google Patents

Description

The present invention relates to a projection device.

Conventionally, projection devices have been used that focus light emitted from a light source on a micromirror display element called a DMD (digital micromirror device) or a display element such as a liquid crystal panel, and display a color image on a screen. For example, Patent Document 1 discloses a projection device that homogenizes light emitted from a light source using a microlens array and irradiates the light on a display element that is a DMD, forming image light on the display element.

JP 2014-119702 A

Light guided from the light source side is irradiated onto the image forming surface of the display element, but light irradiated outside the effective area where image light is formed is wasted light. In the projection device of Patent Document 1, the direction of the optical axis of the light from the light source side is changed and the light is guided to the display element. However, depending on the direction of the optical axis change, the light may be guided while rotating around the optical axis, and if the amount of light irradiated outside the effective area increases, the efficiency of use of the light source light decreases.

The present invention aims to provide a projection device that efficiently forms image light.

The projection device of the present invention comprises a microlens array that homogenizes a light beam emitted from a light source, a light-guiding optical system that rotates the light beam emitted from the microlens array around an optical axis and guides it, and a display element that is irradiated with the light beam guided by the light-guiding optical system to form image light, and is characterized in that the microlens array is rotated and positioned so that the irradiation area of the light beam on the display element approximately coincides with the effective area of the display element.

The present invention provides a projection device that efficiently forms image light.

FIG. 2 is a diagram showing functional blocks of a projection device according to an embodiment of the present invention. FIG. 2 is a schematic plan view showing an internal structure of a projection device according to an embodiment of the present invention. 1 is a schematic plan view of a fluorescent wheel according to an embodiment of the present invention; FIG. 2 is a diagram showing a microlens array according to an embodiment of the present invention as viewed from the light exit surface side. 3 is a diagram showing the optical paths of light emitted from each microlens of the microlens array according to the embodiment of the present invention. FIG. 2 is a schematic plan view of a light-guiding optical system according to an embodiment of the present invention, with some lenses omitted, as viewed from the positive Z-axis direction. FIG. 2 is a schematic front view of the light-guiding optical system according to the embodiment of the present invention, with some lenses omitted, as viewed from the Y-axis positive direction. FIG. 1A and 1B are schematic diagrams showing the distribution of light intensity of light irradiated onto the incident surface side of a microlens array according to an embodiment of the present invention, in which (a) shows red wavelength band light irradiated onto a rotated microlens array, and (b) shows red wavelength band light irradiated onto a non-rotated microlens array. 5A and 5B are schematic diagrams showing the distribution of light intensity of light irradiated onto the incident surface side of a microlens array according to an embodiment of the present invention, in which (a) shows light in the green wavelength band and (b) shows light in the blue wavelength band. 1A and 1B are schematic diagrams showing the inclination of a light beam in a light-guiding optical system according to an embodiment of the present invention, in which (a) shows the light beam between a microlens array and a second reflecting mirror, (b) shows the light beam between the second reflecting mirror and a display element, and (c) shows the light beam at the image forming surface of the display element.

The following describes an embodiment of the present invention with reference to the drawings. FIG. 1 is a diagram showing functional circuit blocks of the projection device control unit of the projection device 10. The projection device control unit is composed of a CPU including an image conversion unit 23 and a control unit 38, a front-end unit including an input/output interface 22, a display encoder 24, and a formatter unit including a display drive unit 26. Image signals of various standards input from the input/output connector unit 21 are converted by the image conversion unit 23 via the input/output interface 22 and system bus (SB) to unify them into image signals of a predetermined format suitable for display, and then output to the display encoder 24.

The display encoder 24 expands and stores the input image signal in the video RAM 25, generates a video signal from the contents of the video RAM 25, and outputs it to the display driver 26.

The display driver 26 drives the display element 51, which is a spatial light modulator (SOM), at an appropriate frame rate in response to the image signal output from the display encoder 24.

The projection device 10 irradiates the light beam emitted from the light source device 60 onto the display element 51 via the light source optical system 140, forming an optical image with the light reflected from the display element 51, and projects and displays the image on a projection target such as a screen (not shown) via the projection optical system 220 (see also FIG. 2). The movable lens group 235 of the projection optical system 220 can be driven by the lens motor 45 for zoom adjustment and focus adjustment.

The image compression/expansion unit 31 compresses the luminance and color difference signals of the image signal using processes such as ADCT and Huffman coding, and performs recording processing by writing the data sequentially to a memory card 32, which is a removable recording medium.

Furthermore, the image compression/expansion unit 31 reads out image data recorded on the memory card 32 in the playback mode, and expands each piece of image data constituting a series of moving images on a frame-by-frame basis. The image compression/expansion unit 31 outputs the image data to the display encoder 24 via the image conversion unit 23, and performs processing to enable the display of moving images, etc., based on the image data stored in the memory card 32.

The control unit 38 is responsible for controlling the operation of each circuit within the projection device 10, and is composed of a CPU, a ROM that stores fixedly operating programs such as various settings, and a RAM used as a work memory.

Operation signals from the key/indicator section 37, which is composed of main keys and indicators provided on the top panel of the housing, are sent directly to the control section 38. Key operation signals from the remote controller are received by the Ir receiving section 35, and the code signals demodulated by the Ir processing section 36 are output to the control section 38.

The control unit 38 is connected to the audio processing unit 47 via a system bus (SB). This audio processing unit 47 is equipped with a sound source circuit such as a PCM sound source, and in the projection mode and playback mode, converts audio data into analog form and drives the speaker 48 to output audible audible sound.

The control unit 38 also controls the light source control circuit 41, which functions as a light source control unit. The light source control circuit 41 can control the operation of the light source device 60, which includes the excitation light irradiation device 70, the red light source device 120, and the fluorescent wheel device 100, which will be described later, so that light in a specific wavelength band required for image generation is emitted from the light source device 60.

Furthermore, the control unit 38 causes the cooling fan drive control circuit 43 to detect temperature using multiple temperature sensors provided in the light source device 60, etc., and controls the rotation speed of the cooling fan based on the results of this temperature detection. The control unit 38 also controls the cooling fan drive control circuit 43 to continue rotating the cooling fan using a timer or the like even after the power to the projection device 10 body is turned off, or to turn off the power to the projection device 10 body depending on the results of temperature detection by the temperature sensors.

Next, the internal structure of this projection device 10 will be described. Figure 2 is a schematic plan view showing the internal structure of the projection device 10. Here, the housing of the projection device 10 is formed in a roughly box shape, and includes a front panel 12, a rear panel 13, a right panel 14, and a left panel 15. In the following description, left and right in the projection device 10 refer to the left and right directions relative to the projection direction, and front and rear refer to the screen side direction of the projection device 10 and the front and rear directions relative to the traveling direction of the light beam.

The projection device 10 has a light source device 60 located approximately in the center of the housing. Between the light source device 60 and the left panel 15, a light guide optical system 180 and a projection optical system 220 are arranged.

The light source device 60 includes an excitation light irradiation device 70 that is a light source of blue wavelength band light and also an excitation light source, a red light source device 120 that is a light source of red wavelength band light, and a green light source device 80 that is a light source of green wavelength band light. The green light source device 80 is composed of the excitation light irradiation device 70 and a fluorescent wheel device 100. The light source device 60 also includes a light source optical system 140 that guides blue wavelength band light, green wavelength band light, and red wavelength band light. The light source optical system 140 includes a blue light path side focusing lens 146, a first focusing lens 147, a second focusing lens 148, and a third focusing lens 149 as multiple lenses. The light source optical system 140 also has a first dichroic mirror 141, a second dichroic mirror 144, a blue light path side reflecting mirror 143, and a first reflecting mirror 145. The light source optical system 140 focuses the light beams emitted from the light source devices of each color (excitation light irradiation device 70, green light source device 80, and red light source device 120) onto the entrance surface 901 of the microlens array 90.

The excitation light irradiation device 70 is disposed in the approximate center of the housing of the projection device 10 in the left-right direction, near the rear panel 13. The excitation light irradiation device 70 has a light source group of blue laser diodes 71, a reflection mirror group 75, an excitation light path side focusing lens 77, a diffusion plate 78, etc. The light source group is formed by a plurality of blue laser diodes 71, which are semiconductor light emitting elements arranged so that their optical axes are parallel to the rear panel 13. The blue laser diodes 71 constituting the light source group are arranged in a matrix of two rows and four columns. The excitation light irradiation device 70 is connected to a heat sink 79 via a heat pipe and is cooled.

The group of reflecting mirrors 75 has multiple reflecting mirrors arranged in a stepped pattern, and reduces the effective diameter of the light beam emitted from the blue laser diodes 71 in one direction before emitting the light. The group of reflecting mirrors 75 converts the optical axis of the light emitted from each blue laser diode 71 by approximately 90 degrees toward the front panel 12.

The red light source device 120 has a red light emitting diode 121 arranged so that its optical axis is parallel to the blue laser diode 71, and a second condensing lens group 125 that condenses the light emitted from the red light emitting diode 121. The red light emitting diode 121 is a semiconductor light emitting element that emits red wavelength band light. The red light source device 120 is arranged so that the optical axis of the red wavelength band light emitted from the red light source device 120 intersects with the optical axis of the blue wavelength band light emitted from the excitation light irradiation device 70 and the optical axis of the green wavelength band light emitted from the fluorescent wheel 101. The red light source device 120 is connected to a heat sink 126 via a heat pipe and is cooled.

The fluorescent wheel device 100 constituting the green light source device 80 is disposed on the optical path of the blue wavelength band light emitted from the excitation light irradiation device 70 and in the vicinity of the front panel 12. The fluorescent wheel device 100 includes a fluorescent wheel 101 disposed parallel to the front panel 12 (in other words, perpendicular to the optical axis of the emitted light from the excitation light irradiation device 70), a motor 110 that rotates and drives the fluorescent wheel 101, and a drive control device (not shown) that drives and controls the motor 110. The fluorescent wheel device 100 also includes a first condenser lens group 111 that condenses the ray bundle of the excitation light emitted from the excitation light irradiation device 70 onto the fluorescent wheel 101 and condenses the ray bundle of the green wavelength band light emitted from the fluorescent wheel 101 toward the rear panel 13, and a lens member 142 that condenses the light that has passed through the fluorescent wheel 101 and reflects it toward the blue light path side condenser lens 146. The drive control device is controlled by the light source control circuit 41 described above.

The fluorescent wheel 101 shown in FIG. 3 is formed in a disk or annular shape, and the opening 112 side is connected to the shaft of the motor 110 to be rotatable. The fluorescent wheel 101 has a fluorescent light-emitting region 310 and a transmission region 320 arranged in parallel in the circumferential direction as a plurality of light source segments. The base material 102 of the fluorescent wheel 101 can be formed of a metal base material such as copper or aluminum. The surface 102a of the base material 102 on the excitation light irradiation device 70 side is mirror-processed by silver deposition or the like. The fluorescent light-emitting region 310 has a green phosphor layer formed on the mirror-processed surface 102a. The fluorescent light-emitting region 310 receives blue wavelength band light emitted from the excitation light irradiation device 70 as excitation light, and emits fluorescent light (green wavelength band light) in the green wavelength band in all directions. The green wavelength band light is emitted from the fluorescent wheel device 100 and enters the first condenser lens group 111 on the first dichroic mirror 141 side.

The transmission region 320 of the fluorescent wheel 101 can be formed by fitting a transparent substrate having translucency into a cutout portion formed in the substrate 102 of the fluorescent wheel 101. The transparent substrate is made of a transparent material such as glass or resin. The transparent substrate may also have a diffusion layer on the surface on the side where the blue wavelength band light is irradiated or on the opposite side. The diffusion layer can be provided, for example, by forming fine irregularities on the surface of the transparent substrate by sandblasting or the like. The blue wavelength band light from the excitation light irradiation device 70 incident on the transmission region 320 has a condensed diameter narrowed by the excitation light path side condenser lens 77 and the first condenser lens group 111, is transmitted or diffused through the transmission region 320, and is emitted to the lens member 142 side. The blue wavelength band light is condensed in the transmission region 320 (or in front of or behind the transmission region 320) and the light beam is inverted around the optical axis. The transmission area 320 of the fluorescent wheel 101 becomes the optical reference plane A3 (optical reference point) of the light beam that enters the microlens array 90 described below (see also FIG. 2).

The fluorescent wheel 101 is driven to rotate, and when the fluorescent light emitting region 310 of the fluorescent wheel 101 is located in the irradiation region S of the blue wavelength band light shown in FIG. 3, the green wavelength band light excited by the blue wavelength band light is emitted toward the first focusing lens group 111. On the other hand, when the transmission region 320 of the fluorescent wheel 101 is located in the irradiation region S of the blue wavelength band light, the blue wavelength band light is transmitted through the fluorescent wheel 101 and guided to the lens member 142.

Returning to FIG. 2, the first dichroic mirror 141 is disposed at a position where the blue wavelength band light emitted from the excitation light irradiation device 70, the green wavelength band light emitted from the fluorescent wheel 101, and the red wavelength band light emitted from the red light source device 120 intersect. The first dichroic mirror 141 transmits the blue wavelength band light and the red wavelength band light, and reflects the green wavelength band light. Therefore, the optical axis of the green wavelength band light emitted from the fluorescent wheel 101 is converted by 90 degrees toward the second focusing lens 148.

The lens member 142 is arranged on the optical axis of the blue wavelength band light transmitted or diffused through the fluorescent wheel 101, and reflects the blue wavelength band light to convert the optical axis by 90 degrees to the blue light path side focusing lens 146. The blue light path side focusing lens 146 is a biconvex lens and is arranged on the left panel 15 side of the lens member 142. The blue light path side reflecting mirror 143 is arranged on the left panel 15 side of this blue light path side focusing lens 146. The first focusing lens 147, which is flat-convex (single convex) with the exit side convex, is arranged on the rear panel 13 side of the blue light path side reflecting mirror 143. The blue light path side reflecting mirror 143 converts the blue wavelength band light focused by the blue light path side focusing lens 146 by 90 degrees to the rear panel 13 side and makes it incident on the first focusing lens 147.

A second condenser lens 148 that is plano-convex (single-convex) with a convex surface on the incident side is disposed on the left panel 15 side of the first dichroic mirror 141. Furthermore, a second dichroic mirror 144 is disposed on the left panel 15 side of the second condenser lens 148, on the rear panel 13 side of the first condenser lens 147. The second dichroic mirror 144 reflects red wavelength band light and green wavelength band light to convert the optical axis by 90 degrees toward the rear panel 13 side, and transmits blue wavelength band light.

The optical axis of the red wavelength band light transmitted through the first dichroic mirror 141 and the optical axis of the green wavelength band light reflected by the first dichroic mirror 141 so as to coincide with the optical axis of the red wavelength band light are incident on the second focusing lens 148. The red wavelength band light and green wavelength band light transmitted through the second focusing lens 148 are then reflected by the second dichroic mirror 144 and incident on the third focusing lens 149. On the other hand, the blue wavelength band light focused by the first focusing lens 147 is transmitted through the second dichroic mirror 144 and incident on the third focusing lens 149.

The third focusing lens 149 is a convex lens (positive meniscus lens) having a convex surface on the incident side and a concave surface on the exit side. The third focusing lens 149 focuses the red wavelength band light, green wavelength band light, and blue wavelength band light incident from the second dichroic mirror 144 side and emits them to the first reflecting mirror 145 side. The light beam emitted from the third focusing lens 149 is guided to the microlens array 90 side by the first reflecting mirror 145, with its optical axis being converted. Note that, if the light beam at the position on the optical reference planes A1 to A3 (optical reference points) is considered to be the object side, the microlens array 90 is positioned at a position where the light guided by the light source optical system 140 is approximately imaged (i.e., the position where the images F1 to F3 of the light beam beam on the optical reference planes A1 to A3 are formed). The shapes of the images F1 to F3 of the light beams irradiated onto the incident surface 901 of the microlens array 90 are illustrated in Figures 8(a), 9(a), and 9(b) described below.

The light guide optical system 180 has a concave lens 181, a convex lens 182, a second reflecting mirror 183, and a condenser lens 184. The condenser lens 184 emits image light emitted from the display element 51 arranged on the rear panel 13 side of the condenser lens 184 toward the projection optical system 220, and is therefore also considered to be part of the projection optical system 220. The concave lens 181 is arranged between the microlens array 90 and the convex lens 182 (in other words, the optical path between the microlens array 90 and the display element 51). The convex lens 182 is also arranged between the concave lens 181 and the second reflecting mirror 183 (in other words, the optical path between the microlens array 90 and the display element 51).

The light emitted from the microlens array 90 enters a biconcave concave lens 181, where the light beam is expanded, and then enters a convex lens 182. The convex lens 182 is formed to be biconvex, with the convex surface on the exit side having a greater curvature than the convex surface on the entrance side. The convex lens 182 collects the light emitted from the concave lens 181 and emits it toward the second reflecting mirror 183. The light reflected by the second reflecting mirror 183 is irradiated at a predetermined angle to the display element 51 via the condenser lens 184. The display element 51, which is a DMD, is cooled by a heat sink 190 provided on the rear panel 13 side.

Here, the configuration of the microlens array 90 will be described. FIG. 4 is a front view of the microlens array 90 as viewed from the exit surface 902 side. The microlens array 90 is formed in a rectangular plate shape (square plate shape in this embodiment). As shown in the enlarged view of part Q, the microlens array 90 has a plurality of microlenses 91 that are rectangular when viewed from the front. Each microlens 91 is formed as a biconvex lens having convex surfaces on the entrance surface 901 side and the exit surface 902 side. The microlenses 91 are arranged in a matrix shape, with approximately 50 microlenses arranged in the long direction of the microlens 91 and approximately 80 microlenses arranged in the short direction of the microlens 91. The upper side 92 and lower side 93 of the microlens array 90 are formed so as to be parallel to the long side 91a of the microlens 91. In addition, the left side 94 and right side 95 are formed so as to be parallel to the short side 91b of the microlens 91.

The microlens array 90 is held by a lens holder 180a fixed to an optical case (details not shown) in the projection device 10 shown in FIG. 2. The microlens array 90 is arranged so that the entrance surface 901 and the exit surface 902 perpendicular to the optical axis P are inclined with respect to the XY plane. The upper surface 92 and the lower surface 93 (or the long side 91a) are also arranged so as to be inclined with respect to the XY plane. In this embodiment, the microlens array 90 is arranged so that the long side 91a of the microlens 91 is rotated by an angle θ1 around the optical axis P with respect to the XY plane. A bundle of light rays guided from the light source optical system 140 is incident on the entrance surface 901 of the microlens array 90. On the incident surface 901, as described later in FIG. 8(a), FIG. 9(a), and FIG. 9(b), images F1 to F3 (specifically, image F4 which is a schematic representation of the shape and inclination of each of images F1 to F3) on optical reference surfaces A1 to A3 are irradiated at an angle of θ2 around the optical axis P with respect to the microlens array 90. The light beam irradiated as image F1 on the incident surface 901 is diffused for each partial region corresponding to each microlens 91, and is guided to overlap with the display element 51.

Figure 5 is a schematic diagram showing the optical path of the light-guiding optical system 180, omitting the second reflecting mirror 183 and the condenser lens 184. The microlens array 90 and the concave lens 181 are arranged in contact with each other (see also Figure 2). The microlens array 90 homogenizes the light (blue wavelength band light, green wavelength band light, red wavelength band light) incident on the incident surface 901 and irradiates it onto the image forming surface 511 of the display element 51.

For example, light L1 (including optical axis light L11 and marginal light L12 and marginal light L13 of microlens 91A) incident on and emitted from microlens 91A on the center side of optical axis P is incident on concave lens 181. Concave lens 181 diffuses (widens the light beam) the incident light L1 and emits it toward convex lens 182. Light L2 (including optical axis light L21 and marginal light L22 and marginal light L23 of microlens 91B) incident on and emitted from another microlens 91B away from optical axis P also enters concave lens 181. Concave lens 181 diffuses (widens the light beam) the incident outer diameter side light L2 and emits it toward convex lens 182.

The convex lens 182 is disposed at a predetermined distance from the concave lens 181. The light beam emitted from the concave lens 181 is incident on the convex lens 182 with the collected diameter expanded to a certain extent. The convex lens 182 collects the incident light L1 in a direction in which the collected diameter of the light beam is reduced (collects the light so that the expansion angle with the optical axis P becomes smaller), and emits it to the display element 51 side. The convex lens 182 also collects the light L2 passing through the outer diameter side with respect to the optical axis P, and emits it to the display element 51 side in the same way as the light L1 passing through the optical axis P side. Therefore, the light L1 and light L2 incident on the display element 51 are guided to the display element 51 in a state where they are close to parallel light.

By using the microlens array 90, even if light with a biased luminance distribution enters the incident surface 901 side, the light is superimposed for each partial area corresponding to each microlens 91, so that uniform light can be irradiated onto the image forming surface 511 of the display element 51.

In addition, since the convex lens 182 in this embodiment is biconvex, it has a short focal length and can irradiate the light beam onto the effective area S1 of the display element 51 (see also FIG. 10(c)) over a relatively short distance. Therefore, the optical path length from the convex lens 182 to the display element 51 can be shortened, and the light source device 60 and the projection device 10 can be made smaller.

Next, the rotation of the light beam guided by the first reflecting mirror 145 and the light guide optical system 180 will be described mainly with reference to Figures 6 to 10. Note that in Figures 6 and 7, the concave lens 181, the convex lens 182, and the condenser lens 184 are omitted. Also, in Figures 6 to 10, the expansion and contraction of the condensed diameter of the light beam by the microlens array 90, the concave lens 181, the convex lens 182, and the condenser lens 184 is not taken into consideration, and mainly the light (red wavelength band light Lr, green wavelength band light Lg, and blue wavelength band light Lb) incident on the microlens array 90 and the amount of rotation of the light beam L emitted from the microlens array 90 around the optical axis P are described. Note that the light beam L is shown as a parallel light having a rectangular light cross-sectional shape emitted from the emission surface 902, and is shown diagrammatically by the optical paths of the four corner light beams P1 to P4. In addition, the cross-sectional shape of this light beam L is a rectangle similar to the microlens 91 when viewed from the exit surface 902 side in FIG. 4, and is inclined around the optical axis P at the same angle θ1 as the microlens 91 (or the microlens array 90).

First, in the optical path on the light source optical system 140 side, the light beam of the red wavelength band light Lr, the green wavelength band light Lg, or the blue wavelength band light Lb guided from the light source (red light source device 120, green light source device 80, or excitation light irradiation device 70) side is guided along the negative Y-axis direction by an optical axis approximately parallel to the light source side light guiding surface (plane parallel to the XY plane) and is irradiated to the first reflection mirror 145. The first reflection mirror 145 reflects the light beam so as to convert the optical axis in an inclined direction (negative X-axis direction, positive Y-axis direction, and negative Z-axis direction) with respect to the light source side light guiding surface. The microlens array 90 and the second reflection mirror 183 are arranged on the optical axis of the light beam reflected by the first reflection mirror 145. The microlens array 90 is arranged so that the entrance surface 901 and the exit surface 902 are perpendicular to the optical axis P and are inclined obliquely with respect to the XY plane, the YZ plane, and the ZX plane.

8(a), 9(a) and 9(b) are schematic diagrams of the microlens array 90 irradiated with the red wavelength band light Lr, the green wavelength band light Lg and the blue wavelength band light Lb, respectively, viewed from the incident surface 901 side. Also, FIG. 8(b) illustrates, as a comparative example, a state in which the microlens array 90 irradiated with the red wavelength band light Lr is arranged without rotating around the optical axis P (i.e., a position when the edge lines (or long sides 91a) of the upper side surface 92 and the lower side surface 93 are arranged parallel to the XY plane). On the incident surface 901, images F1 to F3 of the red wavelength band light Lr, the green wavelength band light Lg and the blue wavelength band light Lb are formed on the optical reference planes A1 to A3. Note that the image F4 shown by the dashed line shows the approximate shape and inclination of the light cross-sectional shape of the red wavelength band light Lr, the green wavelength band light Lg and the blue wavelength band light Lb.

First, FIG. 8(a) shows the irradiation area of the red wavelength band light Lr on the incident surface 901 by the contour lines of light intensity, and further shows the distribution of light intensity at the A-A cross section position and the B-B cross section position of this irradiation area. In the case of the optical path of the red wavelength band light Lr, as shown in FIG. 2, the optical reference plane A1 is the light emitting surface (light emitting point) of the red light emitting diode 121. The red light emitting diode 121 emits the red wavelength band light Lr from its approximately rectangular light emitting surface. Therefore, the red wavelength band light Lr is irradiated on the incident surface 901 in an approximately rectangular area with a relatively uniform distribution of light intensity. In addition, the red wavelength band light Lr is further rotated and tilted by an angle θ2 in the clockwise direction around the optical axis P with respect to the microlens array 90 (microlens 91). That is, the rotation angle (angle θ1 + angle θ2) of the red wavelength band light Lr around the optical axis P is greater than the angle θ1 with respect to the light source side light guide surface (surface parallel to the XY plane) of the microlens array 90. The Z2 axis is parallel to the right side surface 95 (the left side surface in FIG. 8B) of the microlens array 90 and is an axis perpendicular to the optical axis P.

The microlens array 90A shown in FIG. 8(b) shows the position when the microlens array 90 is arranged without being rotated around the optical axis P. The Z1 axis is parallel to the right side surface 95 of the microlens array 90A and is perpendicular to the optical axis P.

When light is incident on the microlens array 90, the orientation of the rectangular microlens array 90 and the rectangular image F4 may not match, resulting in a lightless region 903 on the incident surface 901 where no light is irradiated. In the example shown in FIG. 8B where the microlens array 90 is not tilted (i.e., not rotated around the optical axis P) with respect to the optical light guide surface (a surface parallel to the XY plane), the microlens array 90A and the schematic image F4 of the red wavelength band light Lr are rotated and shifted relative to each other by a rotation angle of angle θ1 + angle θ2 as described above. In this embodiment, as shown in FIG. 8A, the microlens array 90 is rotated by an angle θ1 in the same direction around the optical axis P (clockwise direction as viewed from the incident surface 901) in accordance with the rotation direction of the irradiation region (image F4) of the red wavelength band light Lr (similar to the green wavelength band light Lg and blue wavelength band light Lb).

Therefore, the deviation of the rotation angle between the microlens array 90 and the image F4 of the red wavelength band light Lr is reduced by the angle θ1. In this way, by rotating the microlens array 90 in a direction in which the microlens array 90 and the image F4 of the red wavelength band light Lr are aligned, the area of the no-light region 903 can be reduced. By reducing the area of the no-light region 903, the area (light region) in which the image F4 is located on the incident surface 901 also becomes larger, so that the red wavelength band light Lr incident on the incident surface 901 can be irradiated to more microlenses 91. Therefore, the red wavelength band light Lr incident on the microlens array 90 can be divided into more partial regions and superimposed on the display element 51, and the distribution of the light intensity of the red wavelength band light Lr can be made more uniform. In other words, by reducing the ratio of the no-light region 903, the microlens array 90 can be made smaller while still having the function of uniforming the light beam.

In the case of the optical path of the green wavelength band light Lg, the optical reference plane A2 is the light emitting surface (light emitting point) of the fluorescent light emitting region 310 on the fluorescent wheel 101 (see FIG. 2). The green wavelength band light Lg shown in FIG. 9(a) is an image F2 formed by approximately imaging the fluorescence emitted in all directions from the fluorescent light emitting region 310, which is the optical reference plane A2. Therefore, the green wavelength band light Lg is irradiated on the incident surface 901 in an approximately circular shape in which the distribution of light intensity radially weakens from the optical axis P side. The outline of the irradiation area of the green wavelength band light Lg is formed in an approximately rectangular shape, as shown by the dashed line image F4, and this image F4 is inclined at an angle θ2 in the clockwise direction around the optical axis P with respect to the microlens array 90 (microlens 91) at approximately the same angle as the red wavelength band light Lr.

In the case of the optical path of the blue wavelength band light Lb, the optical reference plane A3 is the exit surface or the light collection surface (exit point) of the transmission area 320 on the fluorescent wheel 101 (see FIG. 2). The blue wavelength band light Lb shown in FIG. 9(b) is emitted from a plurality of blue laser diodes 71 arranged in a matrix (2 rows and 4 columns in this embodiment), so that it is approximately imaged as an image F3 with a strong light intensity distributed in a matrix on the entrance surface 901, which is the image formation surface. The entire irradiation area of the blue wavelength band light Lb is formed in a roughly rectangular shape as shown by the dashed line image F4, and is tilted at an angle θ2 in the clockwise direction around the optical axis P with respect to the microlens array 90 (microlens 91) at approximately the same angle as the red wavelength band light Lr.

In this way, the light beam guided along the light source side light guiding surface (a surface parallel to the XY plane) enters the incident surface 901 with the cross-sectional shape of the light rotated so as to be inclined with respect to the light source side light guiding surface, but the microlens array 90 is also rotated in the same direction around the optical axis P (clockwise as viewed from the incident surface 901) for the green wavelength band light Lg and the blue wavelength band light Lb so that the area of the lightless region 903 is reduced in accordance with the rotation direction of the green wavelength band light Lg and the blue wavelength band light Lb.

Next, the rotation of the light beam L guided in the light-guiding optical system 180 will be described. In Figures 6 and 7, the second reflection mirror 183 reflects the light beam L, which is the outgoing light guided from the microlens array 90 side, so as to convert the optical axis P in an inclined direction (positive direction of the X-axis, negative direction of the Y-axis, and positive direction of the Z-axis) relative to the light source side light-guiding surface (surface parallel to the XY plane). The light beam L reflected by the second reflection mirror 183 is irradiated onto the display element 51 having an image forming surface 511 arranged parallel to the ZX plane.

The light beam L guided between the microlens array 90 and the second reflecting mirror 183 is guided in a state rotated around the optical axis P with respect to the XY plane, as shown in the cross-sectional shape of part C1 in FIG. 10(a) (i.e., the long dimension direction of the rectangular cross-sectional shape of the light beam L is inclined at an angle θ1 with the XY plane).

The cross-sectional shape of the light beam L reflected by the second reflecting mirror 183 to the display element 51 is inverted line-symmetrically with respect to the optical axis P, and is further rotated around the optical axis P before being guided. The light beam guided between the display element 51 and the second reflecting mirror 183 is guided in a state where it is not rotated around the optical axis P with respect to the XY plane (i.e., the line connecting the angular light P1 and the angular light P2 (or the line connecting the angular light P3 and the angular light P4) of the light beam L is parallel to the XY plane), as shown in the cross-sectional shape of part C2 in FIG. 10(b). The Z3 axis in the cross section of part C2 is an axis perpendicular to the optical axis P in the cross section of part C2, with the angular light P3 and the angular light P2 direction being positive, and is shown for reference.

Figure 10 (c) shows the light beam L irradiated to the image forming surface 511 of the display element 51. The light beam L irradiated to the display element 51 is irradiated to a rectangular effective area S1 on the image forming surface 511. The light irradiation area S2 is approximately rectangular and is positioned so as to include the effective area S1. The long dimensions of the irradiation area S2 and the effective area 1 are approximately aligned. The light irradiated to the effective area S1 is reflected by the multiple micromirrors of the display element 51 to form image light according to the image data, and is reflected to the projection optical system 220 side (see Figure 2). Note that the irradiation light of the irradiation area S2 that is not included in the effective area S1 becomes waste light.

In addition, in Figures 6 and 7, the light beam L emitted from the second reflection mirror 183 side to the display element 51 is irradiated from a diagonally downward inclined direction toward the image forming surface 511. Therefore, if the light cross-sectional shape at the cross section of part C2 is rectangular, the shape of the irradiation area S2 becomes slightly parallelogram or rhombus. However, this is negligible in this embodiment, and is illustrated as a rectangle in Figure 10 (c).

As described above, in front of and behind the second reflecting mirror 183, the light-guiding optical system 180 can rotate the light emitted from the microlens array 90 side by an angle θ1 around the optical axis P and guide it to the display element 51 side. In other words, the microlens array 90 is rotated around the optical axis P according to the amount of rotation of the light beam in the light-guiding optical system 180 so that the direction of the irradiation area S2 of the light emitted from the light source (light source device 60) side irradiated to the display element 51 coincides with the direction of the effective area S1 of the display element 51. Due to the rotation of the microlens array 90, the inclination angle of the microlens 91 is also arranged so as to approximately coincide with the inclination angle due to the rotation of the light beam in the light-guiding optical system 180.

The light cross-sectional shape at the cross section of part C2 may be rotated (e.g., counterclockwise) around the optical axis P. In this case, the microlens array 90 can be rotated around the optical axis P so that the orientation of the irradiation area S2 of the light emitted from the light source (light source device 60) that is irradiated onto the display element 51 coincides with the orientation of the effective area S1 of the display element 51.

In Figs. 6 to 10, the rotation of the light beam is explained in a schematic manner, but in actuality, the light beams emitted from each microlens 91 as shown in Fig. 5 are rotated by an amount of rotation according to the inclination direction (tilt angle) of the reflection of the second reflecting mirror 183 as shown in Figs. 6 and 7 while the collected light diameter is adjusted by the concave lens 181, the convex lens 182, and the condenser lens 184, and are irradiated so as to overlap on the image forming surface 511 of the display element 51. As a result, uniform, approximately rectangular light is irradiated onto the image forming surface 511 so that the orientations of the irradiation area S2 and the effective area S1 are aligned.

By configuring the projection device 10 as described above, when the fluorescent wheel 101 is rotated synchronously and light is emitted from the excitation light irradiation device 70 and the red light source device 120 at appropriate timing, light in each of the green, blue, and red wavelength bands is incident on the microlens array 90 via the light source optical system 140 and is incident on the display element 51 via the light guide optical system 180. Therefore, the display element 51 displays the light of each color in a time-division manner according to the data, thereby projecting a color image on the screen.

Although the configuration of this embodiment has been described above using FIG. 1 to FIG. 10, other configurations described below may also be applied. For example, in this embodiment, a substantially square plate-shaped microlens array 90 is shown, but the amount of rotation around the optical axis P of the light incident on the incident surface 901 from the light source (red light source device 120, green light source device 80, excitation light irradiation device 70) side can be various inclination angles depending on the configuration of the optical path to the microlens array 90. Therefore, the microlens array 90 may be configured so that the upper side 92 and lower side 93 of the microlens array 90 and the long side 91a of the microlens 91 are non-parallel to each other by cutting out a part of the member in the non-light region 903 portion. Alternatively, the left side 94 and right side 95 may be configured so that the short side 91b is non-parallel to each other.

In addition, in Figs. 8(a), 9(a) and 9(b), an example is shown in which the images F1 to F3 (image F4) of the light beam irradiated onto the incident surface 901 rotate in a clockwise direction as viewed from the incident surface 901 side, but the images F1 to F3 (image F4) irradiated onto the incident surface 901 may be irradiated onto the incident surface 901 in a state where they are rotated in a counterclockwise direction as viewed from the incident surface 901. In this case, the microlens array 90 can be arranged rotated in a direction opposite (e.g., clockwise) to the rotation direction (e.g., counterclockwise) of the images F1 to F3 (image F4) irradiated onto the incident surface 901.

Depending on the size of the light beam and the optical path length, the light guide optical system 180 may be configured to omit the concave lens 181 or the convex lens 182 between the microlens array 90 and the display element 51. For example, when the distance between the microlens array 90 and the display element 51 is relatively short, the light emitted from the concave lens 181 can be irradiated directly (or only through the condenser lens 184 or the second reflecting mirror 183). The concave lens 181 may be configured to be provided between the convex lens 182 and the display element 51, rather than between the microlens array 90 and the convex lens 182. Furthermore, the convex lens 182 may be configured to be provided between the second reflecting mirror 183 and the condenser lens 184, rather than between the concave lens 181 and the second reflecting mirror 183.

In addition, the microlens 91 is not limited to being biconvex, but may be a plano-convex lens with the entrance surface 901 or the exit surface 902 flat.

In the present embodiment, the microlens 91 is formed in a rectangular shape, but the shape of the microlens 91 can be changed according to the shape of the effective area S1 of the display element 51. For example, if the shape of the effective area S1 is square, the shape of the microlens 91 can also be square. Since the light irradiated to the display element 51 is irradiated from an oblique direction with respect to the image forming surface 511, the cross-sectional shape of the light in the light-guiding optical system 180 and the shape of the irradiation area S2 may not be similar to each other. Therefore, the shape of the microlens 91 as viewed from the front may be different from that of the effective area S1, with the aspect ratio or interior angle changed, so that the shape of the irradiation area S2 becomes closer to the shape of the effective area S1. For example, if the shape of the effective area S1 is rectangular (square or rectangular), the microlens 91 can be a parallelogram or a rhombus.

In addition, in this embodiment, an example in which light is made uniform by being incident on the microlens array 90 in a DLP (Digital Light Processing) type projection device 10 has been shown, but the configuration shown in this embodiment can also be applied to a so-called LCD (Liquid Crystal Display) type. For example, the microlens array 90 may be arranged in the optical path between the light source and the liquid crystal filter (liquid crystal panel) that is the display element arranged in three places, and the blue, green, and red lights made uniform by the microlens array 90 may be made to enter the display element. Note that optical elements such as a concave lens 181 and a convex lens 182 may be arranged between the microlens array 90 and the liquid crystal filter as necessary, and multiple condenser lenses may also be arranged between the light source and the microlens array 90.

In this embodiment, the display device includes a microlens array 90 that homogenizes the light beam emitted from the light source, a light guide optical system 180 that guides the light beam emitted from the microlens array 90, and a display element 51 that is irradiated with the light beam guided by the light guide optical system 180 to form image light. The microlens array 90 is rotated and positioned so that the irradiation area S2 of the light beam on the display element 51 and the effective area S1 of the display element 51 approximately coincide with each other.

By aligning the irradiation area S2 with the effective area S1, it is possible to reduce the amount of wasted light that is not used to form image light on the image forming surface 511, so that the projection device 10 can efficiently form image light using the light emitted from the light source.

In addition, the projection device 10, in which the projection area S2 and the effective area S1 are formed in a rectangular shape and the microlens array 90 is arranged so that the long dimension directions of the projection area S2 and the effective area S1 are approximately aligned, aligns the orientations of the projection area S2 and the effective area S1 to reduce wasted light, and the display element 51 can efficiently form image light in a rectangular area.

In addition, the projection device 10, in which the light-guiding optical system 180 guides the light beam emitted from the microlens array 90 by rotating it around the optical axis P, can make the irradiation area S2 on the display element 51 approximately coincident with the effective area S1 by rotating the microlens array 90 around the optical axis P in accordance with the rotation of the light beam L in the light-guiding optical system 180.

In addition, the projection device 10 arranges the microlens array 90 so that each microlens 91 of the microlens array 90 is formed in a rectangular shape when viewed from the front, and the inclination angle of the microlens 91 due to the rotation of the microlens array 90 is approximately equal to the inclination angle due to the rotation of the light beam in the light-guiding optical system 180, and can superimpose the rectangular light emitted by each microlens 91 on the display element 51 side, thereby irradiating the effective area S1 with uniform light.

Also, a configuration has been described in which the microlens array 90 is arranged to rotate around the optical axis in the same direction as the rotation direction of the light beam incident from the light source. This makes it possible to reduce the area of the light-free region 903 on the incident surface 901.

The projection device 10 also includes a light source optical system 140 including a first reflecting mirror (145) that reflects the light from the light source (120, 80, 70) guided parallel to the light source side light guide surface to the microlens array 90 in an inclined direction with respect to the light source side light guide surface, and the microlens array 90 is formed in a rectangular shape. Also, the light beam having a rectangular light cross section guided from the light source rotates so as to be inclined with respect to the light source side light guide surface and enters the microlens array 90. This allows the light emitted from the light source to be widely irradiated onto the entrance surface 901 of the microlens array 90, and the amount of light divided by the microlens 91 can be increased, so that the light that is superimposed and irradiated by the display element 51 can be made more uniform. In addition, when the area irradiated with light is the same in the microlens array 90, the area of the lightless area 903 can be reduced, so that the microlens array 90 can be made smaller.

The light-guiding optical system 180 also has a second reflecting mirror 183 that reflects the light beam emitted from the microlens array 90 in an oblique direction relative to the optical axis of the microlens array 90 and the light source side light-guiding surface, and guides the light to the display element 51. This improves the degree of freedom in the layout of the optical members that guide light to the display element 51. In addition, since light can be irradiated to the display element 51 from an oblique direction, the image light reflected in the front direction of the display element 51 can be emitted toward the projection optical system 220 without being obstructed.

The above-described embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are included in the scope of the invention and its equivalents as set forth in the claims.

The invention described in the first claim of this application is set forth below.
[1] A microlens array that homogenizes a light beam emitted from a light source;
a light guiding optical system that guides the light beam emitted from the microlens array;
a display element that is irradiated with the light beam guided by the light guide optical system and forms an image light;
Equipped with
the microlens array is rotated and disposed so that an irradiation area of the light beam on the display element and an effective area of the display element substantially coincide with each other.
13. A projection device comprising:
[2] The illumination area and the effective area are formed in a rectangular shape,
The microlens array is arranged so that the long dimension directions of the irradiation area and the effective area are substantially aligned with each other.
2. The projection device according to claim 1 .
[3] The projection device according to [1] or [2], wherein the light-guiding optical system guides the light beam emitted from the microlens array by rotating it about an optical axis.
[4] Each microlens of the microlens array is formed in a rectangular shape when viewed from the front,
the microlens array is disposed such that an inclination angle of the microlenses caused by rotation of the microlens array is substantially equal to an inclination angle of the light beam caused by rotation in the light guiding optical system;
4. The projection device according to claim 3.
[5] The projection device according to [3] or [4], characterized in that the microlens array is arranged rotated around the optical axis in the same direction as the rotation direction of the light beam incident from the light source side.
[6] A first reflecting mirror that reflects the light beam from the light source guided along a light-source-side light-guiding surface in a direction inclined with respect to the light-source-side light-guiding surface and guides the light beam to the microlens array,
The microlens array is formed in a rectangular shape,
The light beam having a rectangular cross-sectional shape guided from the light source rotates so as to be inclined with respect to the light source side light guiding surface and enters the microlens array.
6. The projection device according to any one of the above [3] to [5],
[7] The projection device described in [6], characterized in that the light-guiding optical system has a second reflection mirror that reflects the light beam emitted from the microlens array in a direction inclined with respect to the optical axis of the microlens array and the light source side light-guiding surface, and guides the light to the display element.

REFERENCE SIGNS LIST 10 Projection device 12 Front panel 13 Rear panel 14 Right panel 15 Left panel 21 Input/output connector section 22 Input/output interface 23 Image conversion section 24 Display encoder 25 Video RAM
26 Display drive unit 31 Image compression/expansion unit 32 Memory card 35 Ir receiving unit 36 Ir processing unit 37 Key/indicator unit 38 Control unit 41 Light source control circuit 45 Lens motor 47 Audio processing unit 48 Speaker 51 Display element 60 Light source device 70 Excitation light irradiation device 71 Blue laser diode 75 Reflection mirror group 77 Excitation light path side condenser lens 78 Diffuser plate 79 Heat sink 80 Green light source device 90 Microlens array 90A Microlens array 91 Microlens 91A Microlens 91B Microlens 91a Long side 91b Short side 92 Upper side 93 Lower side 94 Left side 95 Right side 100 Fluorescent wheel device 101 Fluorescent wheel 102 Base material 102a Surface 110 Motor 111 First condenser lens group 112 Opening 120 Red light source device 121 Red light emitting diode 125 Second condensing lens group 126 Heat sink 140 Light source optical system 141 First dichroic mirror 142 Lens member 143 Blue light path side reflecting mirror 144 Second dichroic mirror 145 First reflecting mirror 146 Blue light path side condensing lens 147 First condensing lens 148 Second condensing lens 149 Third condensing lens 180 Light guide optical system 180a Lens holder 181 Concave lens 182 Convex lens 183 Second reflecting mirror 184 Condenser lens 190 Heat sink 220 Projection optical system 235 Movable lens group 310 Fluorescent light emission region 320 Transmitting region 511 Image forming surface 901 Incident surface 902 Exit surface 903 Light-free regions A1 to A3 Optical reference planes F1 to F4 Image L Light beam bundle L1, L2 Light L11, L21 Optical axis light L12, L13 Marginal light L22, L23 Marginal light Lb Blue wavelength band light Lg Green wavelength band light Lr Red wavelength band light P Optical axis P1 to P4 Corner light S Irradiation area S1 Effective area S2 Irradiation area θ1, θ2 Angle

Claims (6)

a microlens array for homogenizing a light beam emitted from a light source;
a light guiding optical system that rotates the light beam emitted from the microlens array around an optical axis and guides the light beam;
a display element that is irradiated with the light beam guided by the light guide optical system and forms an image light;
Equipped with
the microlens array is rotated and disposed so that an irradiation area of the light beam on the display element and an effective area of the display element substantially coincide with each other.
13. A projection device comprising: The illumination area and the effective area are formed in a rectangular shape,
The microlens array is arranged so that the long dimension directions of the irradiation area and the effective area are substantially aligned with each other.
2. The projection device according to claim 1. Each microlens of the microlens array is formed in a rectangular shape when viewed from the front,
the microlens array is arranged such that an inclination angle of the microlenses caused by rotation of the microlens array is substantially equal to an inclination angle of the light beam caused by rotation in the light guiding optical system;
2. The projection device according to claim 1 . 4. The projection device according to claim 3, wherein the microlens array is arranged rotated about an optical axis in the same direction as a rotation direction of the light beam incident from the light source side. a first reflecting mirror that reflects the light beam from the light source guided along a light-source-side light-guiding surface in a direction inclined with respect to the light-source-side light-guiding surface and guides the light beam to the microlens array;
The microlens array is formed in a rectangular shape,
the light beam having a rectangular cross-sectional shape guided from the light source rotates so as to be inclined with respect to the light source side light guiding surface and enters the microlens array;
5. The projection device according to claim 1 , wherein the projection device is a projection lens . 6. The projection device according to claim 5, wherein the light-guiding optical system includes a second reflection mirror that reflects the light beam emitted from the microlens array in an inclined direction with respect to the optical axis of the microlens array and the light source side light-guiding surface, and guides the light to the display element .

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