Condenser lens and projection type display device

Abstract

A condenser lens (21) comprises a first surface (211) and a second surface (212). Light including components of the red band, the green band, and the blue band is incident on the first surface (211). The incident light including the components of the red band, green band, and blue band is emitted from the second surface (212). An aspherical convex lens section (213) is formed in the center of the second surface (212). An aspherical concave lens section (214) is formed around the convex lens section (213).

Description

Condenser lens and projection display device

[0001] The present disclosure relates to a condensing lens and a projection display device.

[0002] As described in Patent Document 1, there is a projection display device that irradiates a phosphor with blue laser light emitted from a blue laser diode and projects an image using illumination light emitted by the phosphor.

[0003] JP 2023-168801 A JP 2002-131513 A

[0004] In a projection display device such as that described in Patent Document 1, it is desirable that the red, green, and blue illumination lights emitted from a condenser lens that condenses the red, green, and blue illumination lights travel so that the illumination lights of each color exactly overlap. However, due to chromatic aberration, the red, green, and blue illumination lights may travel with a slight misalignment with each other. Even if an aspherical lens is used as the condenser lens, the red, green, and blue illumination lights may still be misaligned with each other.

[0005] It is desirable to have a condenser lens that can reduce the deviation between the light beams containing red, green, and blue components that exit and travel when the light beam contains red, green, and blue components and a projection display device using the same. It is desirable to have a condenser lens that can achieve such and other desired objectives. The configuration described in Patent Document 2 does not allow for the construction of such a condenser lens.

[0006] A first aspect of one or more embodiments provides a focusing lens comprising a first surface onto which light containing components of a red band, a green band, and a blue band is incident, and a second surface from which the incident light containing components of the red band, the green band, and the blue band is emitted, wherein an aspherical convex lens portion is formed in a central portion of the second surface, and an aspherical concave lens portion is formed around the convex lens portion.

[0007] A second aspect of one or more embodiments provides a projection display device comprising: a blue laser diode that emits blue laser light as blue illumination light containing components in the blue band; a phosphor that receives the blue illumination light, generates and reflects yellow illumination light containing the red band and the green band, or red illumination light containing the red band and green illumination light containing the green band, using a portion of the blue illumination light that has been incident, and reflects another portion of the blue illumination light that has been incident; and the above-mentioned focusing lens that is arranged between the blue laser diode and the phosphor so that the blue illumination light emitted by the blue laser diode is incident on the second surface, and the yellow illumination light, or the red illumination light and the green illumination light, and the blue illumination light reflected by the phosphor are incident on the first surface.

[0008] According to one or more embodiments, the condenser lens can reduce the deviation of the light beams containing the red, green, and blue components that exit and travel when the light beams contain the red, green, and blue components and the blue components are incident on the condenser lens. According to one or more embodiments, the projection display device can project high-quality images.

[0009] FIG. 1 is a diagram illustrating a projection display device according to one or more embodiments. FIG. 2 is a cross-sectional view illustrating a condensing lens according to one or more embodiments. FIG. 3 is an enlarged partial cross-sectional view illustrating a condensing lens according to one or more embodiments. FIG. 4A is a diagram illustrating the effect of improving chromatic aberration achieved by a condensing lens according to one or more embodiments. FIG. 4B is a diagram illustrating chromatic aberration when a condensing lens of a comparative example is used. FIG. 5 is a diagram illustrating a first configuration example of a condensing lens formed using a liquid lens according to one or more embodiments. FIG. 6 is a diagram illustrating a second configuration example of a condensing lens formed using a liquid lens according to one or more embodiments. FIG. 7 is a diagram illustrating a configuration example for controlling the lens shape of a liquid lens in a projection display device using a liquid lens as a condensing lens.

[0010] A condenser lens and a projection display device according to one or more embodiments will be described below with reference to the accompanying drawings. First, the configuration and operation of the projection display device according to one or more embodiments will be described with reference to FIG.

[0011] 1, a projection display device 100 according to one or more embodiments includes a light source 1, a phosphor 2, a polarization conversion element (PCS (Polarization Conversion System)) 3, a dichroic mirror 4, a cross dichroic mirror 5, a dichroic mirror 6, reflective polarizing plates 7R, 7G, and 7B, a color synthesis prism 8, and image display elements 10R, 10G, and 10B. The projection display device 100 also includes condenser lenses 20 and 21, a relay lens 23, condenser lenses 26 to 29, fly-eye lenses 24 and 25, a projection lens 30, and reflecting mirrors 40 to 42.

[0012] The condenser lens 21 is a condenser lens according to one or more embodiments, and is configured by an aspherical lens. The condenser lens 21 may be made of glass, or, as will be described in detail later, may be configured by a liquid lens. One or more condenser lenses may be further disposed between the phosphor 2 and the condenser lens 21. The condenser lens 21 is both a condenser lens and a collimator lens.

[0013] Light source 1 is configured, for example, with a laser array in which a plurality of blue laser diodes BL are arranged. The number of blue laser diodes BL is not limited. Light source 1 emits blue laser light as S-polarized blue illumination light. In FIG. 1 , B indicates blue illumination light or blue image light, which will be described later. Condenser lens 20 condenses the blue illumination light emitted from light source 1. Dichroic mirror 4 reflects the S-polarized blue illumination light emitted from condenser lens 20 and bends the optical path of the blue illumination light by 90 degrees. Condenser lens 21 condenses the blue illumination light and directs the condensed blue illumination light to enter phosphor 2.

[0014] The phosphor 2 has a fluorescent layer that generates yellow illumination light containing red and green band components whose intensity corresponds to the energy intensity of the incident blue illumination light, and a reflective surface. A portion of the incident blue illumination light is incident on the fluorescent layer of the phosphor 2, generating the yellow illumination light. The reflective surface of the phosphor 2 reflects the generated yellow illumination light and the other portion of the incident blue illumination light. Thus, the phosphor 2 emits blue illumination light and yellow illumination light. In FIG. 1 , Y indicates the yellow illumination light. The reflected blue illumination light is scattered within the phosphor 2 and contains P-polarized light.

[0015] The phosphor 2 may have a phosphor layer that generates red illumination light and a phosphor layer that generates green illumination light, instead of the phosphor layer that generates yellow illumination light, and may be configured to generate red illumination light and green illumination light separately. When the phosphor 2 generates red illumination light and green illumination light separately, the yellow illumination light described below will be interpreted as red illumination light and green illumination light.

[0016] The phosphor 2 is circular, and Fig. 1 shows the side of the circular phosphor 2. In order to suppress a temperature rise in the phosphor 2 and to extend the life of the phosphor 2, the phosphor 2 is configured to rotate by a rotation mechanism (not shown).

[0017] The P-polarized blue illumination light and yellow illumination light emitted from the phosphor 2 pass through the condenser lens 21 and the dichroic mirror 4 in this order, and are incident on the relay lens 23. The relay lens 23 causes the incident blue illumination light and yellow illumination light to be incident on the reflecting mirror 40. Note that if the size of the dichroic mirror 4 is limited with respect to the cross section of the optical path, the blue illumination light and yellow illumination light containing both S-polarized and P-polarized light will pass outside the dichroic mirror 4 and be incident on the relay lens 23.

[0018] The reflecting mirror 40 reflects the blue illumination light and yellow illumination light, bending the optical paths of the blue illumination light and yellow illumination light by 90 degrees, and makes them incident on the fly-eye lens 24. The fly-eye lenses 24 and 25 homogenize the illumination distribution of the incident blue illumination light and yellow illumination light. The PCS 3 aligns the incident blue illumination light and yellow illumination light to p-polarized light. The blue illumination light and yellow illumination light emitted from the PCS 3 are incident on the cross dichroic mirror 5 via the condenser lens 26. The cross dichroic mirror 5 separates the blue illumination light and the yellow illumination light.

[0019] The reflecting mirror 41 reflects the separated yellow illumination light, bending the optical path of the yellow illumination light by 90 degrees, and makes it incident on the dichroic mirror 6. The dichroic mirror 6 reflects the green band component contained in the yellow illumination light as green illumination light and transmits the red band component contained in the yellow illumination light as red illumination light, thereby separating the yellow illumination light into green illumination light and red illumination light. In Fig. 1, G represents green illumination light or green image light described later, and R represents red illumination light or red image light described later.

[0020] The red illumination light separated by the dichroic mirror 6 is incident on the reflective polarizing plate 7R via the condenser lens 27. The red illumination light passes through the reflective polarizing plate 7R and is incident on the image display element 10R. The image display element 10R optically modulates the incident red illumination light in accordance with the red component of the image data and emits s-polarized red image light. The red image light is reflected by the reflective polarizing plate 7R and is incident on the color synthesis prism 8.

[0021] The green illumination light separated by the dichroic mirror 6 is incident on the reflective polarizing plate 7G via the condenser lens 28. The green illumination light passes through the reflective polarizing plate 7G and is incident on the image display element 10G. The image display element 10G optically modulates the incident green illumination light in accordance with the green component of the image data and emits s-polarized green image light. The green image light is reflected by the reflective polarizing plate 7G and is incident on the color synthesis prism 8.

[0022] Reflecting mirror 42 reflects the blue illumination light separated by cross dichroic mirror 5, bending the optical path of the blue illumination light by 90 degrees, and directs it to reflective polarizing plate 7B via condenser lens 29. The blue illumination light passes through reflective polarizing plate 7B and enters image display element 10B. Image display element 10B optically modulates the incident blue illumination light in accordance with the blue component of the image data, and emits s-polarized blue image light. The blue image light is reflected by reflective polarizing plate 7B and enters color synthesis prism 8.

[0023] The reflective polarizing plates 7R, 7G, and 7B can be configured, for example, by a wire grid.

[0024] The color combining prism 8 reflects the blue and red image lights and transmits the green image light, combining the red, green, and blue image lights. The projection lens 30 projects the combined image light onto a screen (not shown) to display a full-color image.

[0025] The configuration of the condenser lens 21 will be described with reference to Figures 2 and 3. As shown in the cross-sectional view of Figure 2, the condenser lens 21 has a first surface 211 and a second surface 212 facing the first surface 211. The first surface 211 is an incident surface onto which the blue illumination light and yellow illumination light emitted from the phosphor 2 in Figure 1, i.e., light containing components of the red, green, and blue bands, are incident. The second surface 212 is an exit surface from which the incident blue illumination light and yellow illumination light exit, and is also an incident surface onto which the blue illumination light emitted from the light source 1 (blue laser diode BL) in Figure 1 is incident.

[0026] The condenser lens 21 has a circular shape when viewed from the first surface 211 or the second surface 212. In the example shown in FIG. 2 , the first surface 211 is flat, but the first surface 211 may be convex. An aspherical convex lens portion 213 is formed in the center of the second surface 212. An aspherical concave lens portion 214 is formed around the convex lens portion 213 on the second surface 212. The concave lens portion 214 is formed between the peripheral edge of the convex lens portion 213 and the peripheral edge 215 of the condenser lens 21. The center of the convex lens portion 213 coincides with the center of the condenser lens 21.

[0027] As shown in Figure 3, in the cross section of the collecting lens 21, the convex lens portion 213 and the concave lens portion 214 are connected to each other at the inflection point Pif. The lowest point of the concave lens portion 214 that is closest to the first surface 211 is designated as P0. When the concave lens portion 214 has the shape shown by the solid line, the lowest point P0 is located relatively close to the convex lens portion 213. When the concave lens portion 214 has the shape shown by the dashed line, the lowest point P0 is located relatively close to the peripheral edge 215. When the concave lens portion 214 has the shape shown by the dashed line, the lowest point P0 is located at a position that coincides with the peripheral edge 215.

[0028] Through verification by the inventors, it has been found that in order to improve chromatic aberration, which will be described later, it is preferable that the lowest point P0 of the concave lens portion 214 be located more inward than the peripheral edge portion 215. When the condenser lens 21 is viewed three-dimensionally, the lowest point P0 is continuous in the circumferential direction, and therefore the circular lowest point that is closest to the first surface 211 of the concave lens portion 214 is located more inward than the peripheral edge portion 215.

[0029] The effect of improving chromatic aberration achieved by the condenser lens 21 will be described using Fig. 4A and Fig. 4B, which is a comparative example. In the example shown in Fig. 4A, the first surface 211 is convex, specifically, spherical. In addition, in the example shown in Fig. 4A, condenser lenses 22a and 22b are disposed between the phosphor 2 and the condenser lens 21.

[0030] The condenser lens 22a has a concave surface at the center of the light incident surface on the side facing the phosphor 2, and a convex surface on the light exit surface. The condenser lens 22b has a concave surface at the center of the light incident surface on the side facing the condenser lens 22a, and a convex surface on the light exit surface. The concave and convex surfaces of the condenser lens 22a and the concave and convex surfaces of the condenser lens 22b are spherical.

[0031] In the comparative example of Fig. 4B, condenser lenses 61, 62a, and 62b are used instead of condenser lenses 21, 22a, and 22b in Fig. 4A, respectively. The condenser lens 61 has a flat light incident surface and an aspherical convex light exit surface. The condenser lens 62a has a shape similar to that of the condenser lens 22a. The condenser lens 62b has a flat light incident surface and a convex light exit surface. The concave and convex surfaces of the condenser lens 62a and the convex surface of the condenser lens 62b are spherical.

[0032] 4B , in the comparative example, the red light component indicated by the dashed line (R), the green light component indicated by the dashed line (G), and the blue light component indicated by the solid line, which are emitted from the condenser lens 61, travel with a slight deviation from one another due to chromatic aberration. The wavelengths of the red light component, the green light component, and the blue light component are 630 nm, 550 nm, and 430 nm, respectively. If the projection display device 100 were to include condenser lenses 61, 62a, and 62b between the light source 1 and the phosphor 2, it would be difficult to project a high-quality image.

[0033] In contrast, in a configuration including a condenser lens 21 having aspherical convex lens portions 213 and concave lens portions 214 on the second surface 212, it is possible to reduce the deviation of light of the red band component, the green band component, and the blue band component due to chromatic aberration, as shown in Fig. 4A. The condenser lens 21 shown in Fig. 4A shows a case where the lowest point P0 is located at a position that approximately coincides with the peripheral end 215. Even with a condenser lens 21 where the lowest point P0 is located at a position that approximately coincides with the peripheral end 215, it is possible to reduce the deviation of light. By positioning the lowest point P0 more inward than the peripheral end 215, it is possible to further reduce the deviation of light.

[0034] In the collecting lens 21 shown in Fig. 2, in which the first surface 211 is a flat surface, it is necessary for the incident light to be collected only by the second surface 212. In the collecting lens 21 shown in Fig. 4A, the first surface 211 is a spherical surface, so that the first surface 211 and the second surface 212 can collect the incident light.

[0035] 2 or 4A, blue illumination light incident on a position near the end of the concave lens portion 214 of the condenser lens 21 can be condensed onto the center of the phosphor 2. Therefore, a blue laser diode BL that irradiates blue illumination light at a position near the end of the concave lens portion 214 can be provided in the light source 1, thereby increasing the light intensity of the blue illumination light.

[0036] As described above, the projection display device 100 includes the blue laser diode BL and the phosphor 2. The blue laser diode BL emits blue laser light as blue illumination light containing a blue band component. The phosphor 2 receives the blue illumination light and generates and reflects yellow illumination light containing a red band and a green band, or red illumination light containing a red band and green illumination light containing a green band, using a portion of the incident blue illumination light. The phosphor 2 also reflects the other portion of the incident blue illumination light.

[0037] The projection display device 100 includes a condenser lens 21 disposed between the blue laser diode BL and the phosphor 2. The condenser lens 21 is an aspherical lens onto whose exit surface the blue illumination light emitted by the blue laser diode BL is incident, and onto whose entrance surface the yellow illumination light or the red and green illumination light reflected by the phosphor 2 and the blue illumination light reflected by the phosphor 2 are incident. The condenser lens 21 has an aspherical convex lens portion 213 formed in the center of the exit surface, and an aspherical concave lens portion 214 formed around the convex lens portion 213. This makes it possible to reduce deviations of the red, green, and blue band components of light that emerge from the exit surface and travel, due to chromatic aberration.

[0038] Next, specific configuration examples in which the condenser lens 21 is formed of a liquid lens will be described with reference to Figures 5 and 6. Figure 5 shows a liquid lens 21L1, which is a first configuration example that can be used to form the condenser lens 21, and Figure 6 shows a liquid lens 21L2, which is a second configuration example that can be used to form the condenser lens 21.

[0039] As shown in Figure 5, the liquid lens 21L1 includes a first liquid storage section 2a and a second liquid storage section 2b. The first liquid storage section 2a has a liquid sealed between a non-flexible transparent conductive plate 2a0 and an elastic transparent film 2a1. A plurality of flexible transparent electrodes 2a21, 2a22, and 2a23 are attached to the upper surface of the transparent film 2a1. The number of transparent electrodes attached to the upper surface of the transparent film 2a1 is not limited to three, and more transparent electrodes may be attached to the upper surface of the transparent film 2a1. The transparent conductive plate 2a0 and the transparent electrodes 2a21, 2a22, and 2a23 are electrodes facing each other.

[0040] By attaching a large number of transparent electrodes to the upper surface of the transparent film 2a1, the shape of the first liquid storage portion 2a can be precisely controlled. The transparent electrodes attached to the upper surface of the transparent film 2a1 are preferably divided in the radial and circumferential directions.

[0041] The first liquid storage section 2a is connected to a liquid tank 2a5 by a connecting section 2a4. An actuator 2a6 applies force to the liquid in the liquid tank 2a5. A pressure sensor 2a7 is provided within the liquid tank 2a5. DC variable voltage sources 2a31, 2a32, and 2a33 are connected between the transparent conductive plate 2a0 and transparent electrodes 2a21, 2a22, and 2a23, respectively.

[0042] When a voltage is applied between the transparent conductive plate 2a0 and the transparent electrodes 2a21, 2a22, and 2a23 by the variable voltage sources 2a31, 2a32, and 2a33, the first liquid storage section 2a functions as a capacitor and is charged with opposite positive and negative charges, and an electrostatic attraction force acts between the transparent conductive plate 2a0 and the transparent electrodes 2a21, 2a22, and 2a23.

[0043] The first liquid storage section 2a can displace the transparent film 2a1 so as to shorten the distance between the transparent conductive plate 2a0 and the transparent electrodes 2a21, 2a22, and 2a23 by strengthening the electrostatic attractive force acting between the transparent conductive plate 2a0 and the transparent electrodes 2a21, 2a22, and 2a23. The first liquid storage section 2a can displace the transparent film 2a1 so as to lengthen the distance between the transparent conductive plate 2a0 and the transparent electrodes 2a21, 2a22, and 2a23 by weakening the electrostatic attractive force acting between the transparent conductive plate 2a0 and the transparent electrodes 2a21, 2a22, and 2a23.

[0044] The displacement of transparent membrane 2a1 causes the liquid in first liquid storage portion 2a to move into liquid tank 2a5, and vice versa. Actuator 2a6 applies a force to the liquid in liquid tank 2a5, thereby maintaining the shape of first liquid storage portion 2a. Actuator 2a6 applies a force to the liquid in liquid tank 2a5 in accordance with the pressure detected by pressure sensor 2a7.

[0045] The second liquid storage section 2b has a liquid sealed between non-flexible transparent conductive plates 2a0 and 2b0, an elastic transparent film 2b1, and a non-flexible, non-conductive side wall 2d. A plurality of flexible transparent electrodes 2b21, 2b22, 2b23, and 2b24 are attached to the lower surface of the transparent film 2b1. Transparent electrodes 2b21, 2b22, 2b23, and 2b24 may be attached to the upper surface of the transparent film 2b1. The number of transparent electrodes attached to the upper surface of the transparent film 2b1 is not limited to four, and more transparent electrodes may be attached to the upper surface of the transparent film 2b1. The transparent conductive plate 2b0 and the transparent electrodes 2b21, 2b22, 2b23, and 2b24 are electrodes facing each other.

[0046] The second liquid storage section 2b is connected to a liquid tank 2b5 by a connecting section 2b4. An actuator 2b6 applies force to the liquid in the liquid tank 2b5. A pressure sensor 2b7 is provided within the liquid tank 2b5. DC variable voltage sources 2b31, 2b32, 2b33, and 2b34 are connected between the transparent conductive plate 2b0 and transparent electrodes 2b21, 2b22, 2b23, and 2b24, respectively.

[0047] When a voltage is applied between the transparent conductive plate 2b0 and the transparent electrodes 2b21, 2b22, 2b23, and 2b24 by the variable voltage sources 2b31, 2b32, 2b33, and 2b34, the second liquid storage section 2b functions as a capacitor and is charged with opposite positive and negative charges, and an electrostatic attraction force acts between the opposing transparent conductive plate 2b0 and the transparent electrodes 2b21, 2b22, 2b23, and 2b24.

[0048] The second liquid storage unit 2b can displace the transparent film 2b1 so as to shorten the distance between the transparent conductive plate 2b0 and the transparent electrodes 2b21, 2b22, 2b23, and 2b24 by strengthening the electrostatic attractive force acting between the transparent conductive plate 2b0 and the transparent electrodes 2b21, 2b22, 2b23, and 2b24. The second liquid storage unit 2b can displace the transparent film 2b1 so as to lengthen the distance between the transparent conductive plate 2b0 and the transparent electrodes 2b21, 2b22, 2b23, and 2b24 by weakening the electrostatic attractive force acting between the transparent conductive plate 2b0 and the transparent electrodes 2b21, 2b22, 2b23, and 2b24.

[0049] The displacement of transparent membrane 2b1 causes the liquid in second liquid storage portion 2b to move into liquid tank 2b5, or vice versa. Actuator 2b6 applies a force to the liquid in liquid tank 2b5, thereby maintaining the shape of second liquid storage portion 2b. Actuator 2b6 applies a force to the liquid in liquid tank 2b5 in accordance with the pressure detected by pressure sensor 2b7.

[0050] In the liquid lens 21L1 shown in Fig. 5, the lower surface of the transparent conductive plate 2b0 corresponds to the first surface 211 in the condenser lens 21 shown in Fig. 2, and the transparent films 2a1 and 2b1 correspond to the second surface 212. The transparent film 2a1 portion of the first liquid storage portion 2a functions as a first lens portion with a controllable lens shape, which is formed in the center of the second surface of the first and second surfaces facing each other. Here, the first lens portion is a convex lens portion.

[0051] The transparent film 2b1 in the second liquid storage portion 2b functions as a second lens portion formed around the center of the second surface, the lens shape of which can be controlled independently of the first lens portion. Here, the second lens portion is a concave lens portion.

[0052] As shown in Fig. 6, the liquid lens 21L2 includes a first liquid storage portion 2a, a second liquid storage portion 2b, and a third liquid storage portion 2c. In Fig. 6, parts that are substantially the same as those in Fig. 5 are designated by the same reference numerals, and their description may be omitted. The second liquid storage portion 2b contains a liquid between a non-flexible transparent conductive plate 2b0, an elastic transparent film 2b1, and a non-flexible, non-conductive side wall 2d. The third liquid storage portion 2c contains a liquid between a non-flexible transparent conductive plate 2a0 and elastic transparent films 2b1 and 2c1.

[0053] The third liquid storage unit 2c is connected to a liquid tank 2c5 by a connecting unit 2c4. An actuator 2c6 applies force to the liquid in the liquid tank 2c5. A pressure sensor 2c7 is provided in the liquid tank 2c5. The third liquid storage unit 2c may also be provided with a configuration for controlling its shape using electrostatic attraction.

[0054] According to the liquid lens 21L2 shown in FIG. 6, it is possible to control the shape of the second lens portion with higher precision than with the liquid lens 21L1 shown in FIG.

[0055] In FIG. 5 or 6, the shapes of the first and second lens portions may be controlled by a force from an actuator instead of by an electrostatic attraction force.

[0056] 7, the projection display device 100 can use the liquid lens 21L1 shown in Fig. 5 or the liquid lens 21L2 shown in Fig. 6 as the condenser lens 21. The control unit 50 may control the lens shape of the liquid lens 21L1 or 21L2 in accordance with a user input via the input unit 51.

[0057] The projection display device 100 may be able to select, for example, a mode in which an image is projected using the entire projectable range, or a mode in which a high-brightness image is projected using only the center of the projectable range. When the user selects a mode using the input unit 51, the control unit 50 controls the lens shape of the liquid lens 21L1 or 21L2 so that the lens shape corresponds to the selected mode. The control unit 50 may calculate the lens shape corresponding to the selected mode, or may select the lens shape corresponding to the selected mode from a table.

[0058] When a mode in which an image is projected using the entire projectable range is selected, the control unit 50 may control the lens shape of the liquid lens 21L1 or 21L2 so that the lens shape minimizes chromatic aberration. When a mode in which a high-brightness image is projected using only the center of the projectable range is selected, the control unit 50 may control the lens shape of the liquid lens 21L1 or 21L2 so that the amount of light at the center is maximized.

[0059] 7, the control unit 50 and the input unit 51 may be configured within the projection display device 100, or may be external devices such as a personal computer. The image to be projected onto the screen may be captured by an imaging device, and the image may be checked to see if it has the desired projection characteristics, and the result may be fed back to the control unit 50.

[0060] The present invention is not limited to one or more of the above-described embodiments, and various modifications can be made without departing from the spirit and scope of the present invention.

[0061] This application claims priority based on Japanese Patent Application No. 2024-040790 filed with the Japan Patent Office on March 15, 2024, and Japanese Patent Application No. 2024-040792 filed with the Japan Patent Office on March 15, 2024, the entire disclosures of which are incorporated herein by reference.

Claims

1. A focusing lens comprising: a first surface onto which light containing components of the red, green, and blue bands is incident; and a second surface from which the incident light containing components of the red, green, and blue bands is emitted, wherein an aspherical convex lens portion is formed in the center of the second surface, and an aspherical concave lens portion is formed around the convex lens portion.

2. The focusing lens according to claim 1, wherein the lowest point of said concave lens portion that is closest to said first surface is located inside the peripheral edge of said focusing lens.

3. A projection display device comprising: a blue laser diode that emits blue laser light as blue illumination light containing components of the blue band; a phosphor that receives the blue illumination light, generates and reflects yellow illumination light containing the red band and the green band, or red illumination light containing the red band and green illumination light containing the green band, from a portion of the incident blue illumination light, and reflects another portion of the incident blue illumination light; and a condenser lens according to claim 1 or 2 that is disposed between the blue laser diode and the phosphor so that the blue illumination light emitted by the blue laser diode is incident on the second surface, and the yellow illumination light, or the red illumination light and the green illumination light, and the blue illumination light reflected by the phosphor are incident on the first surface.

4. The focusing lens according to claim 1, which is constituted by a liquid lens comprising: a convex lens portion formed in the center of the second surface of the first surface and the second surface, the convex lens portion having a controllable lens shape; and a concave lens portion formed around the center of the second surface, the concave lens portion having a controllable lens shape independently of the convex lens portion.

5. A focusing lens formed by a liquid lens according to claim 4, wherein the convex lens portion and the concave lens portion are configured so that the lens shape is controlled by electrostatic attractive force acting between opposing electrodes.

6. The projection display device according to claim 3, comprising a condenser lens formed by the liquid lens according to claim 4 or 5.

7. A focusing lens composed of a liquid lens having: a first lens portion, the lens shape of which is controllable, formed in the center of the second surface of a first surface and a second surface opposed to each other; and a second lens portion, the lens shape of which is controllable independently of the first lens portion, formed around the center of the second surface.

Images