Image display device

Abstract

To reduce the temperature difference in an optical system while preventing an increase in temperature of a display element.SOLUTION: An image display device 10 comprises: a display element 120; an observation optical system 100 that guides light from the display element 120 toward an observer; a wiring part 125 that leads out wiring from the display element 120 in a first direction; and a first heat transfer member 210 that is provided on a surface of the display element 120 on the opposite side of the observer. The first heat transfer member 210 has a first extension part 212 that extends in the first direction, and second extension parts 213A, 213B that extend in a second direction different from the first direction.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an image display device. [Background technology]

[0002] In recent years, head-mounted displays (HMDs) have been used as image display devices that are worn on the observer's head and display images in front of the observer's eyes. HMDs are used as devices that enable users to experience virtual reality (VR) and mixed reality (MR) because they allow users to easily view images on a large screen and facilitate stereoscopic viewing.

[0003] An HMD for realizing MR has an imaging unit for capturing images of a subject corresponding to the observer's left and right eyes, a display unit for superimposing and displaying the image captured by the imaging unit on a 3DCG image created by a PC or the like, and an observation optical system for projecting the image onto the observer. The image to be projected onto the observer is displayed on a display element such as a small liquid crystal panel corresponding to each of the observer's left and right eyes, and this image is enlarged through an observation optical system corresponding to each of the observer's left and right eyes, and then projected onto the observer's left and right eyeballs.

[0004] The captured image of the subject is an image with parallax corresponding to both the left and right eyes. Furthermore, by creating a parallax image of the 3DCG image corresponding to both the left and right eyes of the observer and displaying it superimposed on the image captured by the imaging system, it is possible to present a virtual 3DCG image as if it actually exists.

[0005] Polarization optics is a well-known observation optical system that can be made smaller and lighter by folding the optical path. Polarization optics consists of two phase plates and lenses, and is beginning to be used in the field of HMDs, where smaller and lighter products are required.

[0006] Because display elements generate heat when displaying images, they are configured to transfer heat to the surrounding area via wiring, etc., to prevent the temperature of the display element itself and other components from rising above a specified level. When a polarized optical system is used in the observation optical system, a rise in lens temperature or the occurrence of temperature differences within the lens can worsen the birefringence of the lens or change the refractive index, potentially leading to a deterioration in optical performance.

[0007] Patent Document 1 discloses, as a technique relating to a heat dissipation method for an imaging device, an imaging device configured such that heat from a panel substrate is conducted to a heat dissipation section from a contact portion of a heat dissipation sheet. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-54425 Summary of the Invention [Problem to be solved by the invention]

[0009] However, although the technology disclosed in Patent Document 1 can suppress the temperature rise of the display element itself, it has the problem that it does not take into consideration reducing the temperature difference within the optical system arranged around the display element. The present invention has been made in consideration of the above-mentioned problems, and has an object to reduce the temperature difference within the optical system while suppressing the temperature rise of the display element. [Means for solving the problem]

[0010] The image display device of the present invention includes a display element, an observation optical system that guides light from the display element toward a viewer, a wiring portion that draws wiring in a first direction from the display element, and a first heat transfer member that is provided on a surface of the display element opposite to the viewer side. a holding member that holds the observation optical system; and a second heat transfer member that is provided on an outer peripheral surface of the holding member. Equipped with 、 The first heat transfer member is an overlapping portion that overlaps the display element; a first extension portion extending in the first direction; From the overlapping portiona second extension portion extending in a second direction different from the first direction; The first extension portion is attached to the wiring portion, and the second extension portion is directly or indirectly connected to the second heat transfer member. It is characterized by: [Effects of the Invention]

[0011] According to the present invention, it is possible to reduce the temperature difference within the optical system while suppressing the temperature rise of the display element. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a perspective view showing an example of a configuration of an image display device. [Figure 2] FIG. 1 is a perspective view of an image display device as seen from the observer's side. [Figure 3] FIG. 2 is a diagram showing the configuration of an observation optical system. [Figure 4] FIG. 2 is a perspective view showing an example of the configuration of the periphery of the observation optical system of the first embodiment. [Figure 5] FIG. 2 is a perspective view showing an example of the configuration of the dustproof cover of the first embodiment. [Figure 6] FIG. 2 is a perspective view showing a state in which the dustproof cover of the first embodiment is attached to a lens barrel. [Figure 7] FIG. 10 is a perspective view showing an example of the configuration of the periphery of an observation optical system according to a second embodiment. [Figure 8] FIG. 11 is a perspective view showing an example of the configuration of the periphery of an observation optical system according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. [First embodiment] FIG. 1 is a perspective view showing an image display device 10 according to the first embodiment. The image display device 10 of this embodiment is a head-mounted display (HMD) worn on the head. An observer (user) wears the image display device 10 on their head to observe an image. The image display device 10 is equipped with imaging cameras 20L and 20R and alignment cameras 21L and 21R. Note that in each drawing including FIG. 1, the state in which the image display device 10 is worn is taken as the reference, and the observer side is referred to as the rear, the opposite side of the observer side, i.e., the side of a display element 120 described later, is referred to as the front, the upper side is referred to as the top, and the lower side is referred to as the bottom.

[0014] The imaging cameras 20L and 20R are stereo cameras that acquire real images of the surroundings and display them to the observer through lenses 150 and 151, which will be described later. The alignment cameras 21L and 21R are stereo cameras that acquire the position and orientation of the image display device 10 by using feature points, such as markers and object edges, from the acquired images. The image display device 10 of this embodiment is provided with the imaging cameras 20L and 20R and the alignment cameras 21L and 21R separately. The alignment cameras 21L and 21R are monochrome cameras, but perform high-precision and highly fault-tolerant alignment by utilizing a wide angle of view, a high shutter speed, a long baseline length, and the like. However, the image display device 10 may acquire display images and alignment information using only the imaging cameras 20L and 20R. Furthermore, the alignment cameras 21L and 21R in the image display device 10 may be replaced with distance sensors that use ultrasound, infrared rays, or the like.

[0015] FIG. 2 is a perspective view of the image display device 10 of this embodiment as seen from the rear side (viewer side). The image display device 10 is equipped with observation optical systems 100L and 100R on the left and right, respectively, and an observer views images by looking through the observation optical systems 100L and 100R. The image display device 10 is equipped with hoods 11L and 11R around the observation optical systems 100L and 100R. The observer can adjust the left and right positions of the observation optical systems 100L and 100R to match the observer's interpupillary distance by operating the hoods 11L and 11R.

[0016] Figure 3 shows the configuration of the observation optical systems 100L and 100R. Figure 3 is a cross-sectional view taken along line AA in Figure 1, cut approximately horizontally, and viewed from the direction of the arrow. Reference numeral 110 denotes the observer's eyeball. For ease of explanation, the camera and other internal components are omitted from Figure 3. Furthermore, the left observation optical system 100L and the right observation optical system 100R are composed of common components, and when there is no need to distinguish between them, they will be referred to as observation optical systems 100 as appropriate.

[0017] 3, the observation optical system 100 is located between the display element 120 and the observer's eyeball 110, and is held by a lens barrel 190. The observation optical system 100 guides light from the display element 120 toward the observer. Specifically, the observation optical system 100 enlarges and projects the original image displayed on the display element 120 as a virtual image and guides it to the observer's eyeball 110. The observation optical system 100 of this embodiment is an optical system that folds the optical path by using polarized light.

[0018] The observation optical system 100 has lenses 150 and 151 arranged at the front and rear. The lenses 150 and 151 are circular when viewed from the front to back direction and are made of resin. The observation optical system 100 also has a polarizing plate 130 and a first phase plate 140 arranged between the display element 120 and the lens 150, in this order from the front (the display element 120 side), and a half mirror 160 is vapor-deposited on the surface of the lens 150 facing the lens 151. The surface on which the half mirror 160 is vapor-deposited acts as a semi-transmissive reflective surface. The observation optical system 100 also has a second phase plate 141 and a polarizing beam splitter (PBS) 170, which is a polarization separation element, arranged between the lens 151 and the eyeball 110, in this order from the front (the display element 120 side). The second phase plate 141 and the PBS 170 are planar. The first phase plate 140 and the second phase plate 141 are wave plates with a phase difference of λ / 4. The second phase plate 141 is held in contact with the lens 151. The lens barrel 190 holds the polarizing plate 130, the first phase plate 140, and the lenses 150 and 151, thereby holding the entire observation optical system 100.

[0019] Here, the polarization direction of light transmitted through the polarizing plate 130 is inclined by 45° to the slow axis of the first phase plate 140, and the polarization direction of light transmitted through the PBS 170 is inclined by 45° to the slow axis of the second phase plate 141. Furthermore, the polarization direction of light transmitted through the polarizing plate 130 is orthogonal to the polarization direction of light transmitted through the PBS 170. In this configuration, light emitted from the display element 120 passes through the polarizing plate 130 to become linearly polarized light, and passes through the first phase plate 140 to become circularly polarized light. The light passes through the half mirror 160 and the second phase plate 141 to become linearly polarized light (first linearly polarized light). Since the polarization direction of this linearly polarized light is orthogonal to the polarization direction of light transmitted through the PBS 170, the light is reflected by the PBS 170 and passes through the second phase plate 141 to become circularly polarized light. The light is reflected by the half mirror 160 and passes through the second phase plate 141 to become linearly polarized light (second linearly polarized light). However, the polarization direction of this linearly polarized light is different from the previous one and coincides with the polarization direction of light passing through the PBS 170, so it passes through the PBS 170 and is guided to the observer's eyeball 110. The observer's eyeball 110 is approximately aligned with the exit pupil of the observation optical system 100. By using polarization to fold the optical path as in this embodiment, it is possible to achieve a thin optical system with a short focal length, and to observe images with a wide angle of view.

[0020] Next, the configuration of the image display device 10 around the observation optical system 100 will be further described. 4A and 4B are perspective views showing an example of the configuration of the periphery of the observation optical system 100, with Fig. 4A being a view from the rear side (observer side) and Fig. 4B being a perspective view from the front side (display element 120 side). In Fig. 4, some components are omitted for ease of understanding.

[0021] As shown in FIG. 4, the image display device 10 includes an observation optical system 100, a display element 120, an FPC 125, a holder 180, a lens barrel 190, and a heat transfer sheet 210. The display element 120 is disposed in front of the observation optical system 100 and displays an image for the observer to observe. The rear surface of the display element 120 is a display surface, and the front surface is a non-display surface. The display element 120 generates heat when displaying. The display element 120 is, for example, an organic EL panel or a liquid crystal panel.

[0022] The FPC (Flexible Printed Circuits) 125 is a flexible substrate that is integrally formed with the display element 120 and that draws wiring from the display element 120. The FPC 125 corresponds to an example of a wiring section. The FPC 125 of this embodiment is wired so as to be drawn upward (first direction) from the display element 120, and is connected to a relay board (not shown) of the image display device 10. By wiring the FPC 125 upward in this way, part of the heat generated by the display element 120 is conducted upward via the FPC 125.

[0023] The holder 180 adheres and holds the display element 120. When the holder 180 holds the display element 120, it is configured as a single unit. The holder 180 is provided with multiple (four in this example) tabs 181 on both sides in the left-right width direction, at symmetrical positions spaced apart vertically. The tabs 181 protrude outward from the holder 180. Meanwhile, the front surface of the lens barrel 190 is provided with multiple (four in this example) tab accommodating sections 191 corresponding to the tabs 181. The holder 180 is fixed in a state in which it is held relative to the lens barrel 190 by adhering the tabs 181 to the tab accommodating sections 191 with the tabs 181 accommodated in the tab accommodating sections 191. Note that by adjusting the position of the display element 120 relative to the lens barrel 190 with an adjustment tool (not shown) before adhering the tabs 181 to the tab accommodating sections 191, the display element 120 can be positioned with high precision relative to the lens barrel 190.

[0024] The lens barrel 190 holds the holder 180 and the observation optical system 100. The lens barrel 190 corresponds to an example of a holding member. The lens barrel 190 is circular when viewed from the front-to-rear direction and is made of resin. The lens barrel 190 has a storage section 192 for storing the observation optical system 100. The storage section 192 is formed with an inner diameter slightly smaller than the outer diameter of the lens 151 of the observation optical system 100. The lenses 150 and 151 are joined to the storage section 192 with their optical axes aligned in advance. By storing the lens 151 from the rear side so that the outer peripheral surface of the lens 151 fits into the inner peripheral surface of the storage section 192, the optical axes of the lenses 150 and 151 and the center of the lens barrel 190 are aligned. The storage section 192 also has multiple (three in this case) recesses 193A, 193B, and 193C on its outer periphery. The recesses 193A, 193B, and 193C are arranged at equal positions on the outer periphery of the barrel 190, with the intervals between adjacent recesses being approximately the same. When the lenses 150 and 151 are housed in the housing portion 192, the outer periphery of the lens 151 is exposed through the recesses 193A, 193B, and 193C. With the lenses 150 and 151 housed, a UV-curable adhesive is applied to the recesses 193A, 193B, and 193C, and the adhesive is cured by UV irradiation, thereby fixing the observation optical system 100 to the barrel 190 in a state in which it is held via the lens 151. Note that the fixing method for fixing the observation optical system 100 to the barrel 190 is not limited to adhesive. For example, the outer periphery of the lens 150 and the inner periphery of the housing portion 192 may be partially interfered with, and the lens 150 may be press-fitted into the housing portion 192 to fix the observation optical system 100 to the barrel 190. The position where the outer peripheral surface of lens 150 and the inner peripheral surface of housing portion 192 interfere with each other is preferably at an even position on the outer periphery of lens barrel 190. Here, adhesion and press-fitting correspond to examples of fixing means.

[0025] Furthermore, barrel 190 has a plurality of (here, three) hooks 194A, 194B, and 194C provided on the front surface. Hooks 194A and 194B are offset upward from the center of barrel 190 and are positioned apart in the left-right width direction of barrel 190. Hooks 194A and 194B are positioned so as to sandwich FPC 125 between them. On the other hand, hook 194C is offset downward from the center of barrel 190 and is positioned approximately in the center of barrel 190 in the left-right width direction. Hook 194C is positioned below display element 120. Hooks 194A, 194B, and 194C are slidably held on an optical base (not shown) of image display device 10.

[0026] Furthermore, barrel-side graphite sheet 195 is provided on barrel 190 so as to surround the outer periphery of barrel 190. Barrel-side graphite sheet 195 corresponds to an example of a second heat transfer member. Barrel-side graphite sheet 195 is a roughly band-shaped sheet with excellent thermal conductivity. Barrel-side graphite sheet 195 has adhesive on one side and is attached to the outer periphery of barrel 190. Details of barrel-side graphite sheet 195 will be described later.

[0027] In this embodiment, the resin material from which barrel 190 is molded and the resin material from which lenses 150 and 151 are molded have approximately the same linear expansion coefficient. Therefore, even if expansion or contraction occurs due to temperature changes, lenses 150 and 151 deform in the same way as barrel 190, so that lenses 150 and 151 are less likely to be subjected to load, and deterioration of optical performance can be reduced.

[0028] The heat transfer sheet 210 is provided on the front surface (the surface opposite to the viewer) of the display element 120. The heat transfer sheet 210 corresponds to an example of a first heat transfer member. The heat transfer sheet 210 is a sheet made of, for example, copper or a copper alloy, and has excellent thermal conductivity. The heat transfer sheet 210 has adhesive on one side and is attached to the front surface of the display element 120. The heat transfer sheet 210 covers the display element 120 from the front side and is positioned so as to overlap the display element 120 from the front to the rear. The holder 180 described above holds the display element 120 with the heat transfer sheet 210 attached to its front surface.

[0029] Here, the heat transfer sheet 210 of this embodiment has an overlapping portion 211, a first extension portion 212, and a plurality of (here, two) second extension portions 213A and 213B. The overlapping portion 211, the first extension portion 212, and the second extension portions 213A and 213B are integrally formed. The overlapping portion 211 is a portion of the heat transfer sheet 210 that overlaps the display element 120 from front to back. More specifically, the overlapping portion 211 is a portion that is attached to the front surface of the display element 120.

[0030] The first extension portion 212 extends upward (first direction) from the overlapping portion 211. That is, the first extension portion 212 extends in the same direction as the direction in which the FPC 125 is drawn out from the display element 120. Furthermore, the surface of the first extension portion 212 is parallel to the surface of the overlapping portion 211. The first extension portion 212 is attached to the front surface of the FPC 125, and can transfer heat from the FPC 125 to the heat-transfer sheet 210 through the first extension portion 212. Furthermore, the upper end of the first extension portion 212 is positioned lower than the upper end of the FPC 125. In this way, the first extension portion 212 extending upward can improve the heat transfer properties in the upward direction by the heat-transfer sheet 210.

[0031] Second extension portions 213A and 213B extend from overlapping portion 211 in a direction different from the upward direction, here a downward direction (second direction). In this embodiment, the extending direction of first extension portion 212 and the extending direction of second extension portions 213A and 213B are opposite directions. Furthermore, the surfaces of second extension portions 213A and 213B are parallel to the surface of overlapping portion 211. Note that, of second extension portions 213A and 213B, the extending direction of second extension portion 213A is parallel to the extending direction of second extension portion 213B. Furthermore, the lower ends of second extension portions 213A and 213B are positioned above the lower end of barrel 190. In this way, by second extension portions 213A and 213B extending downward, heat transfer in the downward direction can be improved by heat transfer sheet 210.

[0032] In this way, the heat transfer sheet 210 has the first extension portion 212 extending in a first direction and the second extension portions 213A, 213B extending in a second direction different from the first direction, so that the first extension portion 212 and the second extension portions 213A, 213B dissipate heat from the display element 120. Therefore, it is possible to suppress a rise in temperature of the display element 120. Furthermore, it is possible to reduce the temperature difference between the temperature on the first direction side and the temperature on the second direction side within the observation optical system 100. Furthermore, because the first direction and the second direction are opposite directions, the temperature difference within the observation optical system 100 can be reduced more than when the directions are not opposite. Here, opposite directions does not necessarily mean that the first direction and the second direction are diametrically opposed, that is, they differ at an angle of approximately 180 degrees, but also includes cases where the first direction and the second direction differ at an angle of 180 degrees ±45 degrees.

[0033] The second extensions 213A and 213B are folded back at their lower ends, so that their adhesive surfaces are attached to each other. This prevents the adhesive surfaces of the second extensions 213A and 213B from being exposed. Furthermore, as described above, when adjusting the position of the display element 120, it prevents the exposed adhesive surfaces of the second extensions 213A and 213B from sticking to the lens barrel 190 or the like and interfering with the adjustment.

[0034] In addition to the above-described configuration, the image display device 10 of this embodiment also includes a dustproof cover 230. The dustproof cover 230 will now be described with reference to FIG. FIG. 5 is a perspective view showing an example of the configuration of the dust cover 230. As shown in FIG. The dustproof cover 230 is attached to the lens barrel 190 so as to cover the display element 120 from the front side, thereby protecting the periphery of the display element 120 from dust. The dustproof cover 230 corresponds to an example of a cover member. The dustproof cover 230 is provided with flange portions 231 at both positions in the left-right width direction. As shown in FIG. 4(b), a double-sided tape 196 corresponding to the flange portions 231 is provided on the front surface of the lens barrel 190. By adhering the flange portions 231 of the dustproof cover 230 to the double-sided tape 196 of the lens barrel 190, the dustproof cover 230 is attached to the lens barrel 190 in a state where it covers the display element 120 and holder 180 from the front side.

[0035] The dustproof cover 230 has a cover-side graphite sheet 240 on the front surface thereof. The cover-side graphite sheet 240 corresponds to an example of a third heat transfer member. The cover-side graphite sheet 240 is in a sheet form and has excellent thermal conductivity. The cover-side graphite sheet 240 has adhesive on one side and is attached to the front surface of the dustproof cover 230. Cover extensions 241A and 241B are provided on cover-side graphite sheet 240. Cover extensions 241A and 241B are portions that extend downward (second direction) from a portion of cover-side graphite sheet 240 that is attached to dustproof cover 230. In other words, cover extensions 241A and 241B extend in the same direction as second extensions 213A and 213B of heat-transfer sheet 210.

[0036] Fig. 6 is a perspective view showing the state in which dustproof cover 230 is attached to lens barrel 190. For ease of understanding, Fig. 6 shows cover-side graphite sheet 240 and omits dustproof cover 230. 6, cover extensions 241A and 241B of cover-side graphite sheet 240 are connected to the front surfaces of second extensions 213A and 213B of heat-transfer sheet 210, respectively. Cover extensions 241A and 241B extend further downward beyond second extensions 213A and 213B, and bend around the outer periphery of barrel 190 to reach the outer periphery of barrel 190. The portions of cover extensions 241A and 241B that reach the outer periphery of barrel 190 are connected to barrel-side graphite sheet 195 provided on the outer periphery of barrel 190. Specifically, the adhesive surfaces of cover extensions 241A and 241B are attached to the front surfaces of second extensions 213A and 213B, the front surface of barrel 190, and the outer periphery of barrel-side graphite sheet 195. Therefore, second extensions 213A and 213B of heat transfer sheet 210 and barrel-side graphite sheet 195 are indirectly connected via cover extensions 241A and 241B of cover-side graphite sheet 240.

[0037] In this manner, cover extensions 241A and 241B of cover-side graphite sheet 240 provided on dustproof cover 230 connect second extensions 213A and 213B of heat-transfer sheet 210 to barrel-side graphite sheet 195. Therefore, heat generated by display element 120 is conducted upward by heat-transfer sheet 210 (see arrow A1 in FIG. 6 ) and also downward in the opposite direction (see arrow A2 in FIG. 6 ). Next, the heat conducted to heat-transfer sheet 210 is conducted to cover extensions 241A and 241B of cover-side graphite sheet 240, which are connected to second extensions 213A and 213B of heat-transfer sheet 210. Next, the heat conducted to cover extensions 241A and 241B is conducted to barrel-side graphite sheet 195 provided on the outer peripheral surface of barrel 190 (see arrow A3 in FIG. 6 ). Therefore, the heat generated by the display element 120 is transmitted to the entire lens barrel 190 and dissipated, thereby suppressing the temperature rise of the display element 120 itself and reducing the temperature difference within the lenses 150, 151 fixed to the lens barrel 190.

[0038] [Second embodiment] Next, an image display device 30 according to a second embodiment will be described. In this embodiment, the same components as those in the first embodiment will be denoted by the same reference numerals, and the description thereof will be omitted as appropriate. 7 is a perspective view showing an example of the configuration of the periphery of the observation optical system 100 as viewed from the front side (the display element 120 side) of the image display device 30 of the second embodiment. For ease of explanation, the dust cover 230 is omitted from the illustration in FIG.

[0039] The heat transfer sheet 310 of this embodiment has an overlapping portion 211, a first extension portion 212, and second extension portions 313A and 313B. The heat transfer sheet 310 of this embodiment differs from the first embodiment in the configuration of the second extension portions 313A and 313B. Second extensions 313A, 313B extend downward from overlapping portion 211. After extending downward, second extensions 313A, 313B bend around the outer edge of barrel 190 and reach the outer surface of barrel 190. The portions of second extensions 313A, 313B that reach the outer surface of barrel 190 are connected to barrel-side graphite sheet 195 provided on the outer surface of barrel 190. Specifically, the adhesive surfaces of second extensions 313A, 313B are attached to the front of barrel 190, the outer surface of barrel-side graphite sheet 195.

[0040] In this way, second extensions 313A and 313B of heat-transfer sheet 310 are directly connected to barrel-side graphite sheet 195. Therefore, heat generated by display element 120 is conducted upward by heat-transfer sheet 210 (see arrow A1 in FIG. 7 ) and also in the opposite direction, downward (see arrow A2 in FIG. 7 ). Next, the heat conducted to heat-transfer sheet 210 is conducted to barrel-side graphite sheet 195 provided on the outer peripheral surface of barrel 190 (see arrow A3 in FIG. 7 ). Therefore, the heat generated by display element 120 is conducted to the entire barrel 190 and dissipated, thereby suppressing a temperature rise in display element 120 itself and reducing the temperature difference within lenses 150 and 151 fixed to barrel 190. Note that cover-side graphite sheet 240 provided on dustproof cover 230, which is not shown in FIG. 7, may have cover extensions 241A and 241B, or may have a configuration in which cover extensions 241A and 241B are omitted.

[0041] [Third embodiment] Next, an image display device 40 according to a third embodiment will be described. In this embodiment, the same components as those in the first embodiment will be denoted by the same reference numerals, and the description thereof will be omitted as appropriate. 8 is a perspective view showing an example of the configuration of the periphery of the observation optical system 100 as viewed from the front side (the display element 120 side) of the image display device 40 of the third embodiment. For ease of explanation, the dust cover 230 is omitted from the illustration in FIG.

[0042] Lens barrel 390 of this embodiment differs from the first embodiment in that it does not have lens-barrel-side graphite sheet 195 provided on its outer circumferential surface. Therefore, heat generated by display element 120 is conducted upward by heat transfer sheet 210 (see arrow A1 in FIG. 8 ) and also in the opposite direction, downward (see arrow A2 in FIG. 8 ). By conducting heat generated by display element 120 upward and downward in this way, it is possible to reduce the temperature difference between the vertical directions within lenses 150, 151 fixed to lens barrel 390 while suppressing a temperature rise in display element 120 itself. Note that the cover-side graphite sheet 240 provided on the dustproof cover 230, which is not shown in FIG. 8, may have the cover extensions 241A and 241B, or may have a configuration in which the cover extensions 241A and 241B are omitted.

[0043] Although the present invention has been described above in conjunction with various embodiments, the present invention is not limited to these embodiments, and modifications and the like are possible within the scope of the present invention, and the above-described embodiments may be combined as appropriate. In the above-described embodiment, the case where the extending direction of the first extension portion 212 and the extending direction of the second extension portions 213A, 213B are opposite directions has been described, but this is not limited to this case, and any different directions are acceptable.

[0044] In the above-described embodiment, the case where the extending direction of second extension portion 213A and the extending direction of second extension portion 213B are parallel has been described, but this is not the only possible case. For example, the extending direction of second extension portion 213A and the extending direction of second extension portion 213B may not be parallel, but may be different directions. That is, the extending direction of first extension portion 212, the extending direction of second extension portion 213A, and the extending direction of second extension portion 213B may be different directions.

[0045] In the above-described embodiment, the hook 194C is located below the display element 120, and therefore the second extension portion is branched into two to avoid the hook 194C. However, the number of the second extension portion is not limited to two, and may be one, or three or more. In the above-described embodiments, the image display devices 10, 20, and 30 are described as being used in a head-mounted display (HMD), but the present invention is not limited to this and may also be used in a handheld display (HHD) or other display devices. [Explanation of symbols]

[0046] 10, 20, 30: Image display device 100 (100L, 100R): Observation optical system 120: Display element 125: FPC 210: Heat transfer sheet 212: First extension portion 213A, 213B: Second extension portion

Claims

1. A display element; an observation optical system that guides light from the display element toward an observer; a wiring portion that draws out wiring from the display element in a first direction; a first heat transfer member provided on a surface of the display element opposite to the viewer side; a holding member for holding the observation optical system; a second heat transfer member provided on an outer circumferential surface of the holding member, The first heat transfer member includes: an overlapping portion that overlaps the display element; a first extension portion extending in the first direction from the overlapping portion; a second extension portion extending from the overlapping portion in a second direction different from the first direction, the first extension portion is attached to the wiring portion, The image display device, wherein the second extension portion is directly or indirectly connected to the second heat transfer member.

2. 2. The image display device according to claim 1, wherein the first direction and the second direction are opposite directions.

3. The second extension portion is 3. The image display device according to claim 1, wherein the second heat transfer member extends in the second direction and reaches the outer peripheral surface of the holding member, thereby being directly connected to the second heat transfer member.

4. The second extension portion is 3. The image display device according to claim 1, wherein the second heat transfer member is indirectly connected to the second heat transfer member via a third heat transfer member.

5. a cover member that covers the display element from the side opposite to the viewer side, the cover member is provided with the third heat transfer member on a surface opposite to the viewer side, the third heat transfer member has a cover extension portion extending in the second direction; The second extension portion is 5. The image display device according to claim 4, wherein the cover is indirectly connected to the second heat transfer member via the cover extension.

6. The first heat transfer member includes:

6. The image display device according to claim 1, further comprising a plurality of the second extension portions extending in the second direction.

7. 7. The image display device according to claim 1, wherein at least a part of the observation optical system is a lens made of resin.

8. the holding member has a housing portion that houses a circular lens of the observation optical system, The linear expansion coefficients of the lens and the holding member are substantially the same, 5. The image display device according to claim 1, wherein the lens is fixed to the holding member by fixing means at uniform positions on the periphery.

9. 9. The image display device according to claim 8, wherein the fixing means is adhesive or press-fitting.

Images